transcript
International Nonwovens Journal Home PageVolume 8 No. 2 Fall,
1999
Air Filters For Ventilating Systems — Laboratory and
In Situ Testing
Table of Contents
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Guest Editorial Director's Corner Emerging Technology Rsearcher's
Toolbox Standards Development Forum Patent Review
Association Focus; TAPPI The Nonwoven Web Pira Worldwide Abstracts
Association News Nonwovens Calendar
PAPERS Air Filters For Ventilating Systems - Laboratory and In Situ
Testing Original Paper by Jan Gustavsson, Camfi
Evaluation of the Filtration Performance of Biocide Loaded Filter
Media Original Paper by Wayne T. Davis, B. Alan Phillips, Maureen
Dever, Thomas Montie and Kimberly Kelly-Wintenberg, The University
of Tennessee; and Sarah Macnaughton, Microbial Insights, Inc
Characterization of Melt Blown Web Properties Using Air Flow
Technique Original Paper by Peter Ping-yi Tsai, TANDEC, The
University of Tennessee
Foamed Latex Bonding of Spunlace Fabrics To Improve Physical
Properties Original Paper by A. Shahani, Bell Atlantic; D.A.
Shiffler and S.K. Batra, Nonwovens Cooperative Research Center,
North Carolina State University
Fiberglass Surface And Its Electrokinetic Properties Original Paper
by Daojie Dong, Owens Corning
Applications Of On-Line Monitoring of Dynamic Forces Experienced By
Needles During Formation Of Needled Fabrics Original Paper by
Abdelfattah M. Seyam, Nonwovens Cooperative Research Center, North
Carolina State University
Development of Thermal Insulation For Textile Wet Processing
Machinery Using Needlepunched Nonwoven Fabrics Original Paper by
Randeep S. Grewal, Flynt Fabrics; and Dr. Pamela Banks-Lee, North
Carolina State University
Comparison Of Trends In Latex Emulsions For Nonwovens and Textiles:
China and the United States Original Paper by Pamela Wiaczek, Kline
& Company
Fiber Renaissance For The Next Millennium Author's Perspective by
Arun Pal Aneja, DuPont
Publisher Ted Wirtz President INDA, Association of the Nonwoven
Fabrics Industry
International Nonwovens Journal Home Page
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Teruo Yoshimura Secretary General ANIC, Asia Nonwoven Fabrics
Industry Conference
Editors Rob Johnson 609-256-1040 rjnonwoven@aol.com
D.K. Smith 602-924-0813 nonwoven@aol.com
D.K. Parikh TAPPI
Teruo Yoshimura ANIC
Production Editor Michael Jacobsen Jacor Publications, Inc.
201-612-6601 mjacobsen@inda.org
Cover Photo provided by AQF Technologies, Charlotte N.C.
The International Nonwovens Journal is published by INDA,
Association of the Nonwoven Fabrics Industry, P.O. Box 1288, Cary,
NC 27512; www.inda.org. Copyright 1999 INDA, Association of the
Nonwoven Fabrics Industry. No part of
this publication may be reproduced or transmitted in any form or by
any means, electronic or mechanical, including photocopying and
recording, or by any information storage or retrieval system,
except as may be expressly permitted in
writing by the copyright owner. The magazine is sent free-of-charge
to all members of INDA and TAPPI, P.O. Box 105113, Atlanta, GA
30348; 404-209-727; Fax 404-446-6947; and ANNA (Asia Nonwoven
Fabrics Industry Conference),
Soto kanda 6-Chome Bldg. 3Fl, 2-9, Chiyoda-ku, Tokyo, 101, Japan.
The International Nonwovens Journal can not be reprinted without
permission from INDA. INDA¨ is a registered trademark of INDA,
Association of the Nonwoven
Fabrics Industry
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To the Future By Behnam Pourdeyhimi Ph.D., CText ATI, FTI;
Professor, and Co-Director, Nonwovens Cooperative Research Center,
North Carolina State University, College of Textiles
I had the opportunity to attend both INDEX '99 and ITMA '99 earlier
this year. At both, I listened to
messages about continued growth of the nonwovens industry, and
future prospects for the industry in the global economy. At these
meetings, I met with companies involved in various segments of the
industry, including raw material suppliers, roll goods producers,
converters and fabricators of the end use products, and machinery
manufacturers.
What was perhaps the most interesting aspect of my visits was the
fact that most of the processes and products on display did not
exist two or three decades ago; those that did are now referred to
as "aging" technologies. This is not surprising given the new
developments exhibited at INDEX and ITMA, although even the "aging"
processes have also been improved significantly over the same time
period. I came back from these meeting with the feeling that
nonwovens will continue to play a significant role in the
polymer-fiber-textile enterprise for many years to come.
EDITORIAL ADVISORY BOARD Chuck Allen INDA Roy Broughton Auburn
University Robin Dent Albany International Ed Engle Fibervisions
Tushar Ghosh North Carolina State Bhuvenesh Goswami
Clemson University
Fiberglass Frank Harris HDK Industries Albert Hoyle Hoyle
Associates
In the near future ANNA/ANIC will be providing members to the
Editorial Advisory Board from their geographic region.
It has been estimated that this industry contributes more than $30
billion to the U.S. economy, and will continue to grow at a rate of
at least 5-6% annually. This is indeed great news for the
industry!
As a professor and educator, however, I have to wonder about the
availability of the trained human capital required to help sustain
this industry. Presently, the nonwovens industry primarily
undertakes in-house training of individuals with degrees in
engineering or science. This has undoubtedly contributed to the
innovations in the field; however, I am not certain if this can
continue to be a viable option given the
Editor's Corner
Marshall Hutten
Hollingsworth & Vose
Nemours Joginder Malik Nelson Industries Alan Meierhoefer
Dexter Nonwovens
Michele Mlynar
Georgia Tech
Univ. of Oklahoma
Univ. of Tennessee
In the near future ANNA/ANIC will be providing members to the
Editorial Advisory Board from their geographic region.
complexities of the materials, processes and products available
today.
Gaining, and indeed maintaining, leadership in this emerging field
requires substantial investment in human capital as well as
inventing fundamentally new mechanisms for achieving "versatile"
processing; i.e., processing of large volume and specialized
materials with a substantially common production domain AND
environmental compatibility.
In order to maintain the present level of innovation, it is
necessary to develop a more structured model for training our
future nonwoven specialists. In academic institutions, our efforts
in this regard should be focused on training these "new" personnel
with sufficient breadth and depth in the variety of disciplines
that impact the nonwovens industry. This multidisciplinary
education will well prepare them for a role with the new, versatile
and sustainable technologies that will require a fundamental,
adaptable knowledge of process synthesis, integration and
subsequent transfer to industrial production. It is clear that
industry and academia need to engage in open debate on the
important matter of to how to prepare for the future.
Ed. Note: Dr. Pourdeyhimi has recently joined the faculty at NCSU
as Co-Director of the NCRC. Dr. Pourdeyhimi was most recently on
the faculty at Georgia Tech and authored an article in the SPRING,
1999 issue of INJ.
— INJ
Return to International Nonwovens Journal Home Page & Table of
Contents
Editor's Corner
THE DIRECTOR’S CORNER A few years ago there was considerable
concern about the possibility of electromagnetic radiation fields
causing human cancers. The primary concern focused on high power
transmission cables that frequently traverse residential areas.
Many people were concerned that living under or around high powered
transmission lines was injurious to health, particularly the health
of children.
As a result, there was considerable government-sponsored research
to determine the reality of this concern and to quantify the risks
involved. One particular study provided considerable fuel for this
controversy and resulted in numerous expensive actions taken as a
precautionary measure.
The study was produced by a scientist named Richard Liburdy; in it,
he stated that he had proved a link between high voltage lines and
cellular changes in the body that could lead to cancer. This
resulted in an acceleration of research devoted to the topic,
despite the fact that many other studies, particularly those
emanating from Europe indicating that no relationship
existed.
NON-COMPLIANCE CORRELATION EPA Act Non-Compliance Events CAA —
Clean Air Act 0% CERCLA — Comprehensive Environmental Response,
Compensation and Liability Act (Superfund)
9%
CWA — Clean Water Act 29% EPCRA — Emergency Planning and Community
Right-to-Know Act
7%
RCRA — Resource Conservation & Recovery Act 23% TSCA — Toxic
Substances Control Act 12%
Shortly after the study received wide circulation, a whistleblower
told the Federal Government, which had funded this particular
research, that Liburdy had manipulated his data. The Office of
Research Integrity, a bureau within the U.S. Department of Health
and Human Services that monitors many federally funded research
projects investigated. Further examination revealed that Liburdy
had discarded data in preparing a graph for his publication which
did not fall on the line purporting to support the hypothesis. In
fact, further examination revealed that Liburdy had used only 7% of
the data generated during his studies. As a result, Liburdy
requested of the scientific journals that had published his work
that three key
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paragraphs be rescinded. Despite this action Liburdy claimed that
he had done nothing wrong. However, he did leave the Department of
Energy’s Lawrence Berkeley National Laboratory, where he was
employed, and he has lost a portion of the $3.3 million grant from
The National Institutes of Health, Department of Energy and
Department of Defense.
During and since these investigations, other studies have been
published, all of which confirm the fact that there is no link
between the electromagnetic radiation field and living organisms.
Unfortunately, Mr. Liburdy’s deception kept the unfortunate myth
alive for a period of time and fostered many actions of "prudent
avoidance;" the latter term has been concocted to mean that if
there is even a hint of health problem, play it safe and avoid
exposure. As a recent article in the Wall Street Journal points out
(Wall Street Journal, July 27, 1999) prudent avoidance "constitutes
a rejection of science and a triumph of fear over reason" and, as
physicist David Hafemeister of California Polytechnics State
University notes, "prudent avoidance is a delight for plaintiff
lawyers since it is essentially a conclusion that the danger is
probable."
In this case prudent avoidance resulted in massive expenditures in
many different areas and conditions.
Unfortunately, researchers seeking additional government funds know
that research results which promote the concept that a growing
problem exists can help assure a continuation of grants. This has
resulted in what some critics have called "regulatory science."
Unfortunately, the Liburdy episode has not done much to discourage
this viewpoint. Although the falsification of data by Mr. Liburdy
was exposed in 1995 he remained on the job until this past May. His
"punishment" for his unscientific behavior consisted of an
agreement that he would not apply for more Federal grants for a
period of three years.
Science in the Courtroom In recent years there has been
considerable concern about the impact of science in litigation and
in the courtroom environment. Unfortunately, many examples exist
where testimony offered in court cases have been labeled as
"science," but has failed to meet the standards normally expected
of a scientific discipline. In some cases, the deviation from
scientific principles has been appalling.
As Supreme Court Justice Stephen Breyer wrote in an opinion last
year: "Society is becoming more dependent for its well being on
scientifically complex technology, so, to an increasing degree,
this technology underlies legal issues of importance to all of us."
Because of this increasing importance of science in the courtroom,
attention has been focused on ways to insure that only the highest
standards are employed in such contributions.
The Supreme Court of the U.S. has made it very clear that the
judges themselves are responsible for the accuracy and reliability
of scientific evidence presented in their courtrooms. There have
been several recent cases adjudicated by The Supreme Court that has
stressed the absolute necessity to keep junk science out of
technical testimony.
While there can be widespread agreement on the objective, the means
to accomplishing this goal can be difficult delineate.
Some judges have enlisted the use of independent experts. The judge
in the silicone breast implant case, for example, appointed a
four-member panel of independent experts to help him sort through
the science.
An encouraging approach to develop a system that insures the
highest scientific standards in the
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courtroom has been made by the American Association for the
Advancement of Science (AAAS). This organization has been working
with a group from the American Bar Association to study the problem
of scientific evidence in the courtroom. Representatives from these
two groups have been meeting for the past few years as the National
Conference of Lawyers and Scientists. In the past few months, the
AAAS has started a five-year demonstration project in which
independent scientists with the appropriate expertise can be
identified for judges to consider as scientific resources in
determining the truth in litigation.
Although the mechanism has not been completed, the project is
making progress, including establishing and experimenting with the
process by which experts are selected. Several subsidiary bodies
chosen by AAAS staff and the advisory committee will attempt to
develop procedures for both identifying and recruiting such
experts.
Another committee within the national conference is attempting to
develop guidelines to screen experts for potential conflicts of
interest. The use of anonymity in describing potential experts will
likely be helpful in the selection process.
Other groups within the conference are working on the methods to
make expert lists available and to alert the judges of the
appropriate procedures in utilizing such services. Another activity
is directed toward educating the scientists as to the intricacies
of the legal process.
While the initial efforts are being focused on Federal courts, it
likely the project can be extended to State courts if the procedure
proves successful. This is most desirable, as the State courts are
the venue of most tort litigation and especially the most
outrageous tort litigation.
Hopefully these efforts can prove successful and the "legal
lottery" can be eliminated along with the presence of junk science
in the courtroom.
The Value of People It has often been said that a company’s most
valuable single asset is the people they have. The same can be said
of the academic environment; quality of the researchers controls
the quality of the research.
Finding, hiring and keeping good people is a never-ending task for
the research administrator, whether in industry, academe, or
elsewhere.
One of the tools in identifying the best candidates for the job is
embodied in a variety of pre-employment assessments. These are
generally tests that usually consist of questions relating to the
skills, behaviors and attitudes that are necessary for a particular
job and a particular environment. These tests can take many
different forms. The idea behind the test is to identify those
applicants with the best chance of becoming productive scientists
and contributors to the industrial or academic research
effort.
The desirability of picking the right employee is also coupled with
the importance of retaining the employee. The average length of
employment of an individual at any professional job in the United
States has been declining in recent years and is estimated to be
somewhere between two and four years by some human resources
specialists.
Along with the need to retain good researchers is the growing
recognition that everyone needs balance in their lives. There must
be meaning and satisfactions in their work, but this needs to be
balanced with their personal, family and private aspirations. A
recent review of this situation by one human resources
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specialist, Roger E. Herman, gives five reasons why people leave
employment and what to do about the situations. His list of five
reasons for departure include the following:
"It doesn't feel right around here."
"They wouldn't miss me if I were gone."
"I don’t get the support I need to get the job done."
"There’s a new opportunity for growth somewhere else."
"I’m not being adequately compensated."
Herman stresses the essential point that each individual needs to
feel valued in his/her situation. It is important to clearly
exhibit to the employee how their effort fits in with the overall
activity and how it contributes to the success of an organization.
It has been found that compensation is not the motivator it once
was. However, it is still important to have a competitive benefits
package.
Of equal importance are the subtle "perks" that say "I am valued."
There is a need for public recognition, and the research director
that is innovative in selecting the method of such recognition is
making a wise investment.
Incidentally, a book entitled "1001 Ways To Reward Employees"
(Workman Publishing Co. Inc; New York, NY) has been selling very
well. Its author, Bob Nelson (Nelson Motivation, Inc.; P.O. Box
500872, San Diego, CA 92150; 619-673-0690; Fax: 619-673-9031;
www.nelson-motivation.com) has written several books on management
and business skills, and is a very popular speaker.
Protecting The Environment and Your Staff Environmental protection,
along with employee safety and health, are research director's
concerns that seldom actually benefit the bottom line. These
responsibilities are viewed by many in the same way that a lot of
plant managers view filtration: "Filtering our product doesn’t add
any value, it simply adds cost." However, this attitude relates to
an old adage that says: "Do it right the first time and you won’t
have to do it the second time."
It is true that the industrial or academic or research director
spends more time, effort and research resources on these two
factors than the research director of a couple generations ago.
Every old timer can relate stories of how a critical plant run was
made late at night with a "jury rig setup, taking more than a few
risks." However, those times are gone and will never return.
Today’s reality is that the research administrator has
responsibility for occupational health and safety of the group,
along with an environmentally sound operation.
In terms of industrial plant sites, considerable pressure has been
applied by the Environmental Defense Fund (EDF) and the Federal
Government’s EPA (Environmental Protection Agency). A few months
ago, these two organizations jointly launched an internet web site
designed to pinpoint environmental problems. No plant manager, or
research director for that matter, would like their operation's
mistakes, hazards, accidents and just unfortunate incidents
broadcast to the entire world. However, this web site lists plant
and location emission problems by their Zip Code, making it
relatively easy for anyone to check into the performance of their
neighbor. It is a little bit like having the contents of your
closet exposed, skeletons and all.
While many industrial concerns initially expressed dismay at the
thought of such exposure, the result has been surprisingly
different. This site has not been a pandora's box of problems and a
source of major
Directors Corner
Rather interestingly, some trade associations for the chemical,
petroleum and other manufacturing industries have adopted the
information site technique to inform and educate their neighbors as
to their problems and their remedial efforts.
As an example, the Chemical Manufacturers Association (CMA) is
launching a web site called "Chemical Guide." This will be an
information site to the plant, the community, the employees and the
surrounding neighbors. The CMA has developed templates that member
companies can use to report information ranging from environment,
health, and safety statistics to financial information, and even
job postings. As a CMA spokesman has indicated, "It’s not an
attempt to change the public’s perception of the industry; it’s
meant to personalize our facilities."
In a similar vane, many organizations have "gone public" with
respect to injury and illness reports. An example is a new web site
that provides online versions of environmental, health and safety
reports; it is being offered by 111 companies in the U.S.
(www.ehsreports.com). This type of internet site was rather
strongly tilted to environmental reports when initiated; now, many
companies are trying to strike a better balance in providing health
and safety information.
Laboratory tours, plant visits and similar activities where
appropriate, can go a long ways to building positive relationships
with neighbors, employee families and other interested parties.
Such activities can also help to boost the esteem of employees and
staff members. In a time of electronic information, it is often
more prudent to exploit than to resist.
Employee Safety Initiatives In line with the research director’s
concern with employee safety, a frequently asked question is: "What
legal rights do employees have to take actions to see that their
employer complies with OSHA Standards?"
This is an interesting and rather important question for research
directors, plant managers and administrators in general. A rather
definitive answer to this question was recently provided by Daryl
Brown of J.J. Keller & Associates (dbrown2@jjkeller.com). Mr.
Brown indicated that The Occupational Safety and Health Act of 1970
created by OSHA within the Department of Labor was inaugurated to
encouraged employers and employees to reduce workplace hazards and
to implement safety and health programs. This law gives employees
many rights and responsibilities, including the rights to do the
following:
• Review copies of appropriate standards, rules, regulations and
requirements that the employer should have available at the
workplace.
• Request information from the employer on safety and health
hazards in the workplace, precautions that have been taken and
procedures that should be followed if the employee is involved in
an accident or is exposed to toxic or hazardous materials.
• Have access to the employee’s exposure to harmful materials, and
medical records that are relevant to the situation.
• Request the OSHA area director to conduct an inspection if they
believe that hazardous conditions or
Directors Corner
• Have an authorized employee representative accompany the OSHA
compliance officer during any inspection tour.
• The right to respond to questions from the OSHA compliance
office, particularly if there is no authorized employee
representative accompanying the compliance officer doing the
inspection tour.
• The right to observe any monitoring or measuring of hazardous
materials and to examine the resulting records.
• Have an authorized representative or the employee themselves
review the OSHA 200 Log at a reasonable time and in a reasonable
manner.
• Object to the abatement period set by OSHA for correcting any
violation in a citation issued to the employer; this is done by
writing to the OSHA area director within 15 working days from the
date the employer receives the citation.
• The right to be notified by the employer if the employer applies
for a variance from a OSHA standard; also, the right to testify at
the variance hearing and to appeal the final decision.
• The employee has the right to have their name withheld from their
employer upon their request to OSHA, if a written and signed
complaint is filed.
• The right to file a discrimination complaint if the employee is
punished for exercising any of the above rights or for refusing to
work when faced with an imminent danger of death or serious injury
and there is insufficient time for OSHA to inspect the
situation.
While this listing of the employee rights is rather lengthy, a
consideration of each item rather clearly establishes the
appropriateness of each of these rights.
Violations of Environmental Laws Anyone who has been involved in a
laboratory or plant inspection by EPA (Environmental Protection
Agency) inspectors knows how stressful this situation can be. In
many cases, honest efforts have been made to do an effective job
and to abide by EPA Regulations. The sheer volume and complexity of
such regulations, however, often leaves the whole operation on a
rather "chancy" basis.
In a rather unusual exercise, the EPA and the Chemical
Manufacturers Association (CMA) recently collaborated on an effort
to determine why companies fail to comply with environmental
regulations. The CMA was very willing to participate, as explained
by their legal counsel, because "historically the EPA had been
addressing only the symptoms of violations, and here was the
opportunity to find out what the causes are."
The three-year project was carried out as "Root Cause Analysis
Pilot Project." EPA prepared the survey and sent it to 50 member
companies who had encountered problems with violations between 1990
and 1995. These violations were non-criminal, but represented a
breach of the regulations, nevertheless.
The report on the results of the survey
(http://www.epa.gov/oeca/ccsmd/rootcause.html) detail six primary
root causes for facility violations. These causes were as
follows:
1. Facility unaware of the applicability of specific
regulation.
Directors Corner
2. Human error in judgment or responsibility. 3. Failure to follow
EPA procedures. 4. Faulty equipment design or installation. 5.
Problems with compliance by contractors. 6. Various communication
difficulties.
From this study, it was determined that certain kinds of compliance
problems are most regularly associated with particular laws.
Specifically, it was found that the laws relating to two federal
acts have more than one- half the violations involved, primarily
because the laws were confusing and ambiguous. These two items were
EPCRA (Emergency Planning and Community Right-to-Know Act) and RCRA
(Resource Conservation & Recovery Act). On the other hand, the
problems with the Clean Air Act (CAA) did not involve
misunderstandings or permit violations. The violations that did
occur regarding the CAA all involved operational and
procedure-related problems, such as equipment failure and
similar.
The report results are summarized in the chart at the top of this
page.
Again, under the Clean Water Act, most of the problems with faulty
water discharges had their basis in the equipment installation or
design.
Also, it developed that companies which have environmental audit
programs and corporate policies, goals and targets for regulatory
compliance were the best performers as to compliance. These
companies also reported that when violations were found, their
emergency management systems were usually changed to avoid
recurrence of the problems.
From this study, a number of recommendations for both EPA and
industry were provided. For EPA, it was suggested that the agency
articulate its regulations more clearly and provide immediate
compliance assistance and "plain-English" guides for every new
rule. Also, it was suggested that EPA could work more closely with
state and environmental agencies to insure that regulations are
interpreted consistently.
On the part of industry, it was suggested that more effort should
be devoted to the development of comprehensive environmental
management systems and the promotion of a increased level of
awareness of such systems amongst all employees. Accurate,
standardized operating procedures and improved employee training
were also recommended.
—INJ
Return to International Nonwovens Journal Home Page & Table of
Contents
Directors Corner
INJ DEPARTMENTS
EMERGING TECHNOLOGY WATCH Sunlight Barrier Fabrics Because of
publicity, there is a heightened awareness of the dangers of skin
cancer due to exposure to the sun's rays. The risk is not
insignificant, as more than a million cases of skin cancer are
diagnosed in the United States each year, according to the American
Academy of Dermatology. About 45,000 of these cases will be the
deadly strain of skin cancer called melanoma, where the cancerous
growth penetrates the skin layers into the underlying tissue.
Melanoma kills over 7,000 people a year in the U.S.
Responding to this hazard, there has been considerable interest in
the use of clothing to protect against the deleterious effects of
the sun's rays. Clothing, of course, does not eliminate the need
for sun block creams and lotions on exposed areas of skin. However,
for most of the body surface, adequate clothing can provide a very
effective sun block.
The problem is that in the summertime adequate clothing may be
discarded in preference for very light, open fabrics that are more
cool, comfortable and stylish. As a result, there has been
considerable interest in recent years in developing fabrics
specifically designed to block the sun and yet provide comfort and
aesthetics that are normally associated with summertime
clothing.
If a fabric is heavy enough, it can effectively block the sun's
rays. However, there has been considerable effort to develop fabric
finishes for lightweight fabrics that can still provide adequate
protection and yet be lightweight, open, breathable and
stylish.
This has resulted in a rather sudden growth in fabrics and clothing
exhibiting good blockage of sunlight and thereby give strong
protection against the problems associated with sunlight and human
skin.
Unfortunately, no standardized techniques have been developed in
the United States for measuring how well a fabric blocks sunlight.
Australia does have a standard method that applies to new, dry
materials. There are efforts underway in the United States to
establish a voluntary standard.
In the meantime, companies that promote special fabrics as a
solution to the problem are utilizing a variety of methods to
measure the effectiveness. Clothing that is wet or that has been
washed repeatedly
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can have a very different ability for blocking the harmful effects
of the sun.
Some apparel companies have focused on this market niche and offer
a variety of clothing claimed to provide considerable protection.
Such apparel generally is quite expensive, however, and the
consumer is left to gauge whether the additional expense is worth
the claimed protection.
At least one company in Israel has developed a finish technology
which it claims provides the perfect solution to UV protection. As
can be expected, the major focus of this effort has been on
fashionable apparel fabrics, but there are indications that this
technology will be extended to nonwoven structures as well.
The process developed by Golden Guard Technologies Limited
apparently involves the formation of a strong, flexible, breathable
and translucent polyurethane finish that incorporates UV absorbers
and attenuators. It is claimed that fabrics that transmit nearly
50% of the UV light before treatment, show a transmission of only
2-4% after treatment. The claims also indicate the finish results
in a minimal impact on the moisture-vapor transmission rate and on
the fabric hand and drape. This protection is unaffected by
moisture, perspiration and machine washing, and is durable to
abrasion, along with wear and tear, according to the developers
(Golden Guard Technologies Ltd, 21 Havaad Haleumi Street, P.O. Box
16120, Jerusalem 91160, Israel; 972-2-675-1123; Fax:
972-2-675-1195;. www.sunprecautions.com and
www.sunprotection.com.
Reactive Protective Clothing The category of "protective clothing"
covers a broad range of hazards. As discussed in the item above,
even sunlight can be a focus, and an appropriate one, for
protective clothing. Anyone who has dealt with a baby diaper knows
that it is also a form of protective clothing.
More specialized hazards are being considered, however, and some
innovative research is being devoted to such hazards.
A recent development shows a rather dramatic approach to a specific
situation, that of clothing worn by agricultural workers,
specifically those workers exposed to a significant amount of
pesticides. In many such cases the pesticide can pass through the
clothing to the skin of the worker and there constituted a
significant hazard.
The solution worked out by researchers at the University of
California-Davis involved clothing treated with chemicals to
detoxify such pesticides. These investigators treated cotton fabric
used to make shirts with a cyclic hydantoin compound, which grafted
onto the cellulose backbone of the cotton fiber. The fabric is then
treated with a bleaching process similar to that normally used in
washing clothing.
This process, using sodium hypochlorite solution, converts the
hydantoin moiety into a halamine group. Interaction of the halamine
group on the surface of the shirt fabric with carbamate-type
insecticides results in the carbamate breaking down into small,
harmless fragments. In the process, the halamine is converted back
into the hydantoin. Washing the clothing, with a bleach treatment,
then regenerates the halamine, ready to provide the
protection.
Thus, the garment is able to go through a cycle: (1) providing
protection, (2) washing and bleaching, (3) regeneration of active
site, ready to again provide the protection.
Emerging Technology
R - N - H ...............> R - N - Cl <...............
Detoxification
This concept of a reactive fabric undoubtedly has many other
potential applications. In a sense, fabrics with some types of
flame retardant treatment or fabrics with an antibacterial finish
function as reactive fabrics in the appropriate environment.
Innovative thinking should yield other functional groups and
situations where the utility of a nonwoven fabric can be enhanced
by its ability to undergo selective reaction in a pre-determined
environment.
Environmental Technology Forecast As indicated by the item above,
nonwoven products have played a very prominent role in
environmental protection and remediation. This has involved
meltblown technology, needlepunch technology, spunbond technology
and others.
With innovation and ingenuity on the part of nonwoven
technologists, nonwovens can play an increasingly vital role in
dealing with our environment.
To that end, it is well to look at the future of environmental
technology, seeking opportunities for contributions from the
industry's technology. Consequently, the 10 top environmental
technological breakthroughs anticipated in the next decade are
worthy of study and consideration.
These breakthroughs have been predicted by researchers at the U.S.
Department of Energy's Pacific Northwest National Laboratory. While
forecasts of the future are always difficult, and the prediction of
breakthrough events is especially difficult, the list is worthy of
study. Their 10 top breakthroughs are as follows:
Agrogenetics ... This involves genetic engineering and plant
manipulation, which is expected to reduce agricultural impacts on
the environment. Growing crops will require fewer amounts of
pesticides due to greater pest resistance and some crops will be
engineered to require less fertilizer and water while yielding
higher yields. This is an area where agrotextiles will have an
impact.
Smart Water Treatment ... Improvement in the water treatment at
sewage plants, municipal water supply systems will likely result in
automatic adjustments to unplug themselves. Sponge-like grains of
sand will attract and hold nitrates and heavy metals to protect
drinking water. Such smart membranes and filters can have a
powerful impact on environmental protection in the future.
Renewable Energy Storage ... By means of improved power storage
systems, the use of electricity generated by solar and wind power
will show an increase. Renewable energy sources will help slow
increases in greenhouse gases by replacing carbon-based fuels. The
improvement in electric storage batteries will also increase the
utility of such items in transportation and other uses.
Microtechnology ... It is suggested that room air will be heated
and cooled more efficiently by tiny channels of micro-heat pumps,
thus saving considerable energy. Microchemical plants will produce
industrial chemicals as needed, eliminating storage and
transportation safety issues.
Emerging Technology
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Paperless Society ... The use of wireless communications,
innovative displays and individualized web publications will help
reduce the reliance on paper for many activities. Advanced display
systems may imitate paper in flexibility and portability. The
researchers suggest that one approach will involve projecting
images directly on the retina of the eye. This capability, coupled
with a cellular phone, could provide faxes and customized news
anywhere. For paper products that continue to be used,
biodegradable inks will be more common.
Molecular Design ... The use of molecular design for catalysts can
make chemical reactions and processes so precise that little or no
wastes are produced. It suggests that sensors designed at the
molecular level will monitor material and chemical manufacturing
processes more precisely. This will help to halt or correct
processes that are sensitive to temperature changes and other
parameters. This breakthrough may expand uses of nonwovens, but may
also have an impact on the production of nonwoven products.
Bioprocessing ... This concept utilizes microorganisms and plants
that will "grow" environmentally friendly chemicals and biological
products. Included among these materials may be drugs, proteins and
enzymes for many uses. Producing chemical feedstocks, fuels and
pharmaceuticals in this manner will be cost effective and better
for the environment. The researchers suggest that microorganisms
retrieve from extremely hot, cold or forbidding environments
(extremozymes, such as are recovered at hot holes in the ocean
floor) may expand the range of temperatures and conditions used in
manufacturing biotechnical products. This may create opportunities
for new, environmentally friendly bioprocesses while saving time
and energy.
Real-time Environmental Sensors ... By the use of
yet-to-be-developed sensors, supermarkets could detect the presence
of bacteria and other dangerous pathogens in food. Workplace air
quality could be monitored to prevent "sick building syndrome."
Other benefits that may result from monitoring in the environment
include control of airplane and other transportation environments,
preventing infections in hospitals and in municipal water supplies
and in guarding against pathogens potentially used in biological
terrorism.
Enviro-manufacturing and Recycling ... Greatly enhanced
recyclability of a whole range of products may change the
complexion of entire environmental protection in the future.
Increased use of biodegradable material in such things as plastics,
paper, cars and computers will have an impact. Dry cleaning with
liquid carbon dioxide will minimize or eliminate this source of
environmental pollution. Recycling will become "second nature" to
all of the citizens of the world, and recyclates will be a major
resource for future civilizations.
Lightweight Cars ... As the weight of automobiles is reduced by the
use of advanced materials, the family sedan will get at least 80
miles per gallon of gas, generate less pollution and use more
recycled materials. Lighter weight cars will be built with less
steel and more lightweight aluminum, magnesium, titanium and
composites. Advanced metal forming techniques will provide
precisely the strength needed at every point. The 150 pounds of
glass used in today's cars will be cut by a third or more by the
use of a composite sandwich of glass and plastic. Today's 100-pound
air conditioners will weigh half as much, particularly as glass is
specially coated to reflect or absorb heat radiation.
While some of these concepts may sound far fetched, many of them
already have a running start in parent technology. Further details
on the environmental technology forecast coming from the U.S.
Department of Energy can be obtained: Greg Koller at Pacific
Northwest National Laboratory;
Emerging Technology
greg.koller@p&l.gov; 509-372-4864;
http://www.pml.bill/news/back/envirbg.htm.
Return to International Nonwovens Journal Home Page & Table of
Contents
Emerging Technology
INJ DEPARTMENTS
RESEARCHERS TOOLBOX
Good ideas are always welcomed by the effective researcher. Good
ideas can help get a difficult job done easily. Sometimes the right
method or tool can get results that would be difficult to do any
other way. Occasionally, the right idea provides a result that
simply could not be accomplished otherwise. Hence, a new trick to
put into the collection of tricks is always a worthwhile addition.
If you have such an item to share, please let us know so we can
include it in a future offering.
Here's hoping that one of the current collection will prove
useful.
Temperature Indicators In dealing with thermal processes it is
sometimes vital to know the maximum temperature reached by a fabric
or system. It would be very convenient to be able to insert
something that would register the maximum temperature, or would
give a signal if a certain temperature is achieved.
A quick, inexpensive and easy solution to this need can often be
obtained with the use of temperature monitor product. These can be
paper or film label products having a window or small panel that
changes color upon being exposed to a set temperature. Often a
label or tape product will carry a series of four-to-eight spots
that correspond to a specific temperature. When the product is
exposed to that temperature, the spot changes from a light color to
black or some such dark color, so there can be no doubt that the
temperature was experienced.
Self-adhesive temperature monitoring labels can be attached to a
web undergoing thermal treatment, giving a positive indication that
a certain temperature was achieved within the web. Such monitoring
labels can have spots indicating a temperature of 100F between each
rating. Other styles have temperature differentials of 250 or 500 F
between spots. The spots or indicator panels can have a variety of
shapes and configurations, including circles, micro-dots, buttons,
bars, and forms of bull's eye, clock and thermometer
configurations.
In general, the temperature range of 1000 to 5000 F is available,
and an accuracy of 1% is guaranteed. Such temperature monitoring
systems can also be provided in a pencil or stick version, which
allows a mark to be made on a surface which then changes as that
specific temperature is achieved. Also, the products are provided
in paint form so that a cover or machine housing can be converted
into a temperature-indicating probe.
The monitoring tape product is often used with fusing ovens or
fusing presses, to confirm the fact that a temperature adequate for
a fabric bonding step has been achieved. This can be done by
placing the indicator on a belt traversing the oven, or between
layers of fabrics or sheets. This has been particularly useful
in
Researchers Toolbox
applications involving the bonding of nonwoven fusible interlinings
and interfacings to outer face fabrics.
A well-established source for such products is Tempil, Inc. (2901
Hamilton Boulevard, South Plainfield, NJ 07080; 800-757-8301; Fax:
908-757-9273). Their products can also be reviewed at
http://www.tempil.com.
Supercritical Fluids in Fibers Research Considerable interest has
been shown in the use of supercritical fluids (SCF) in a wide
variety of experimental and research applications. Where such
detailed interests exist, applications almost invariably
follow.
The use of SCF methods in analytical laboratories has grown
substantial over the past few years. This has been applied
especially to extraction and chromatographic methods, where the
elimination of toxic or difficult solvents has been a boon, along
with the accompanying greatly reduced extraction times.
A very interesting application of SCF technology in the fibers
sector has recently come out of research work done at the Georgia
Institute of Technology. This has focused on the dyeing of fibers,
textiles and polymers and likely presages further search for
suitable applications in the fibers and polymer sectors.
One of the most popular solvents for using SCF technology is carbon
dioxide. This solvent is especially attractive as it is
nonflammable, nontoxic and low cost. It is easily separated from
other solvents and substrates, and when so released, it is
non-polluting. This solvent is particularly useful with polymeric
materials, as it behaves as a plasticizer and can swell many
polymers. Because of this attribute, its low viscosity and its high
solute diffusivity, it can penetrate many polymers with ease. This
character also allows the solvent to carry many materials into
polymeric substrates, fostering mass transfer processes.
SCF carbon dioxide is easily absorbed by many polymers. In some
cases, the solvent can plasticize glassy polymers at relatively low
temperatures; with rubbery polymers above their glass transition
temperatures, the polymer volume can be substantially increased.
These properties can aid in extraction of materials from the
polymers, or conversely can aid in the transport of materials as
additives or impregnants, depending upon specific conditions
employed.
Carbon dioxide is a gas at normal conditions of temperature and
pressure. However, if the temperature is sufficiently lowered, the
gas can be converted into a solid (dry ice). If the pressure is
increased sufficiently, the gaseous carbon dioxide is converted
into a solid or a liquid, dependent upon the temperature. At one
condition of temperature and pressure, all three phases of the gas
(solid, liquid and gas, the triple point) can exist in equilibrium;
for carbon dioxide, the triple point is 310 C and 74 bar. pressure.
Above this point, the material can generally be maintained in the
liquid state, the preferred state for SCF work. By judicious
selection of the pressure and temperature, diffusion rates can be
controlled for extraction work or for impregnation processes.
The work at Georgia Tech focused on the use of SCF carbon dioxide
for the dyeing of fibers, textiles and polymers. Hence, the
capability of the system for impregnation was particularly studied.
These efforts confirmed the basic capabilities of the system, as
reported by others. The research was extended by studying both
phases of the dyeing process, the solubilization of the dyestuff
molecule and the diffusion into the polymer matrix.
Rather surprisingly, the Georgia Tech researchers found that the
dyestuff could have low solubility in the solvent and still be
effective in dyeing. They concluded this result was due to the fact
that SCF dyeing can be effective because of the high partition
coefficient, the dyestuff molecule preferring the polymer
environment to that of the solvent. This property made for high
dyeing efficiency and minimized dyestuff loses in the disposed
liquor and vessel walls.
As might be expected, the treatment did result in the extraction of
some oligomers and surface agents from
Researchers Toolbox
polyester fibers, for example. Other researchers have shown that
such treatment can also affect fiber morphology, but no more so
than the effects of heat and tension.
Despite the fact that special equipment is required to obtain the
temperatures and pressures needed, the interesting results of this
work, and the inherent simplicity and cleanliness of the process,
suggest utility of SCF technology in other fiber research and
applications.
For more information, see: Drews, M. J. and Jordan, C., Text. Chem.
and Color. 30, 13-20 (1998). The work at Georgia Institute of
Technology is summarized at: Kazarian, S. G., Noel, H.B., and
Eckert, C.A., Chemtech, 36-41 (July 1999).
Microthermal Analysis Thermal methods of chemical and physical
analysis are well-established techniques for characterizing and
quantifying the morphology and composition of polymers and fibers.
Differential scanning calorimetry (DSC), thermogravimetric analysis
(TGA), thermomechanical analysis (TMA) and dynamic mechanical
analysis (DMA) are all useful resources on the palette of the fiber
and polymer scientist.
By adding the option of temperature modulation superimposed on the
conventional linear heating or cooling program, further information
and resolution is possible in many of these cases.
Even with such extensions of the basic techniques, however, these
methods give only an averaged or a sample-averaged view of the
condition within a polymer matrix. In order to measure the thermal
properties of a small domain with the polymer, it is generally
necessary to go to a microscopic scale. With some restrictions,
secondary ion mass spectroscopy (SIMS) or X-ray photoelectron
spectrometry (XPS) can provide some focused information, but these
techniques have limitations and complexities.
The efforts to bring together the capabilities of both thermal
methods with microscopic techniques have resulted in the
commercialization of an instrument called the Micro-Thermal
Analyzer™, specifically, the TA 2900. The instrument combines the
capabilities of thermal methods and micro visualization. It is
achieved by combining an atomic force microscope (AFM) with a
thermal probe.
The TA 2900 is capable of providing four images or views of the
surface of a sample:
Topography1.
After these images have been acquired, any specific location on the
sample can be further analyzed by what the instrument producer
calls "Micro-Thermomechanical Analysis" and "Micro-Modulated
Differential Thermal Analysis." The manufacturer claims these
"micro" techniques are comparable with the usual "macro"
counterparts.
By means of this micro-thermal methodology, polymer blends can
yield useful information. If the blends are immiscible, a two-phase
domain structure results; the thermal properties of each individual
domain can then be determined. If a single phase results,
indicating miscibility, this becomes apparent from the thermal
properties of this main phase.
Similar chemical and physical information can be obtained with this
equipment and technology on multi-layered films, indicating the
thermal composition and compatibility of the various layers. The
thermal nature, leading to precise characterization, of defect
areas have also be explored by this technology.
Researchers Toolbox
While the equipment is rather expensive, some consulting physical
testing laboratories are acquiring the equipment and offering
customized analyses.
Source of the equipment: TA Instruments Ltd., Europe House, Bilton
Center, Cleeve Road, Leatherhead, KT 227UQ, Surrey, UK;
44+1372/360-363; Fax: 44+1372/360-135; tlever@taeurope.co.uk.
Wetting of Nonwoven Fabrics The wetting of a nonwoven fabric by
water and other liquids is of critical importance in many nonwoven
applications. The most obvious situation, and one which has been
studied extensively, is the wetting of nonwoven topsheet of a
diaper by urine voided by the wearer. A rapid wetout and passage of
the liquid through the nonwoven is critical to the performance of
baby diapers and similar absorbent sanitary products.
Standard test methods have been developed and carefully studied to
measure the property of fabric wetting in this setting. Nonwoven
diaper facing typically requires a wet-out or strike-through time
of only a few seconds to be acceptable by most converters.
The wetting performance of a fabric can be determined quite simply:
Place a drop of water from an eyedropper or similar device to give
a relatively constant size drop; carefully observe the drop and
determine the time required for the drop to be absorbed into the
fabric. Once wetting of the liquid occurs, absorbency into the
fabric generally occurs very rapidly. If the droplet stays on the
surface as an intact sphere for a considerable period of time, the
fabric has poor or no wetting performance.
Water (pure or otherwise) can be replaced by saline solution (0.9
weight percent sodium chloride solution), physiological saline
solution (sodium chloride plus other minor constituents), synthetic
urine, synthetic menstrual fluid, synthetic blood or a variety of
other liquids. The time of wetting can be controlled by a variety
of methods, and can also be automated. The time of wetting can
usually be determined fairly easily, as the droplet tends to show a
somewhat different visual appearance and to spread slightly
immediately shortly before disappearing into the interior of the
fabric.
For those who want a more precise or quantitative method,
variations have been used with some success. For a pure scientific
method, the traditional contact angle of the Lucas Washburn
equation is often attempted. However, upon study it is soon
realized that the scientific contact angle is dependent upon having
a smooth, pure, uniform surface where the interface of liquid,
solid and gas can be assessed. Looking at the surface of a nonwoven
fabric clearly shows that these requirements are not met.
Much work has been done on single fiber wetting to substitute for
the shortcomings of a fabric surface characteristics. This can
yield considerable useful information, but it often departs
substantially from the environment encountered by the drop of
liquid on a nonwoven fabric surface.
One approach to measuring the contact angle of nonwoven fabrics was
offered by Cusick and Hopkins (Cusick, G.E. and Hopkins, Teresa,
INDA Journal of Nonwoven Research, 1, No. 1, pp. 32-34, 1989). This
method involves an apparatus which holds the test fabric and can be
rotated until the meniscus formed by the liquid and the fabric
"disappears," or the liquid at the fabric surface is level.
Clearly, a controlled technique is needed that approximates the
control, precision and preciseness and versatility of the contact
angle method, while allowing adaptability to the radically
different character of a fabric surface.
A useful adaptation and amalgamation of these desires is afforded
by a method described in a U.S. patent that was granted a few years
ago. The method was originally devised to assess the ability and
suitability of a nonwoven filter fabric surface to quickly wet out
and pass whole blood, such as involved in a blood bank collection
operation. With suitable filtration, depletion of the leucocytes
(white blood cells) in the blood can be
Researchers Toolbox
achieved. These are the cells which have surrounded bacteria,
viruses and other blood debris; their removal from the collected
blood can greatly improve the quality of the blood, and rid it of
the normal risk for a transfusion patient.
To be practical, an infusion set-up for injecting the blood into a
patient must work correctly every time; a blood filter unit that
slows or halts the flow of blood from the collection/storage bag
into the patient cannot be tolerated. The pressure driving the
blood flow is modest; only that coming from a height of several
inches.
As a consequence of a need for a quick, definitive laboratory test,
the inventors of this patent fashioned a modified test method that
mimics the utility of the contact angle method, applied to the
needs and surface of a nonwoven filter medium. Their method is
called the "Critical Wetting Surface Tension (CWST)."
The method involves a series of test solutions having a range of
surface tensions. A set of test solutions is prepared so that each
solution has a surface tension of about 3.0 units different than
the other solutions. The set of test solutions is prepared so that
it covers the range from pure water (73 dynes/cm) to that of a
fluorocarbon liquid (25 to 30 dynes/cm range).
The test is carried out by placing 10 standard-sized drops of a
test liquid on the surface of the nonwoven fabric. A timer is
started at that time, providing for a 10-minute time interval. The
test drops are observed for letting and absorption into the fabric
at the end of that time interval. If at least nine of the 10 drops
are absorbed within the 10-minute test period, it is concluded that
the test solution wets the fabric. If less than nine of the ten
drops are absorbed within the 10-minute time period, it is
concluded that the liquid does not wet the fabric. Tests are run
with the solutions from the set of standard surface tension samples
until two test solutions with surface tensions separated by no more
than 3.0 dynes/cm are identified, the one test solution wetting the
fabric (giving at least nine out of 10 drops that wet the fabric),
and the other test solution not wetting the fabric (gives less than
nine out of 10 drops that wet the fabric). The fabric wetting
performance, CWST, is then calculated as the average surface
tension of the two identified test solutions.
While the CWST is not exactly identical with the surface character
measured by the critical angle test method, it is a very good
empirical substitute, and can nicely characterize a nonwoven fabric
surface. Such characterization can be very useful for many
situations. There appears to be a relationship with the CWST of a
nonwoven fabric and the specific surface energy of the pure polymer
making up the fibers of a pure fabric (non-blended fibers). Also,
the CWST correlates well with the specific surface energies of the
pure polymer making up fibers in a blended fiber fabric. The
presence of fiber finish and other surface treatments, additives
and modifications that affect the fiber surface can be detected.
The importance of surface tensions of the participating liquids of
the application can also be delineated.
By using 10 drops of the test fluid, a good average is obtained,
even taking into account the non-uniformities of a typical fabric
surface. The use of test solutions with relatively small
differences in surface tension, and the averaging of data points
also helps to even out any abnormalities and departures from strict
test methodology.
The end result is a versatile, empirical test method that can be
very useful in a variety of applications.
Source: "Device and method for depletion of the leukocyte content
of blood and blood components." U.S. Patent No. 4,925,572 (May 15,
1990). Inventor: David B. Pall. Assignee: Pall Corporation.
Kilobytes versus Kibibytes A previous issue of INJ (Vol. 7, No. 2;
Spring, 1995) featured a table in the Researcher's Tool Box that
outlined the prefixes to be used for increasing and decreasing
orders of magnitude. Thus, for an increase of 10, 100 or 1,000
times, a simple prefix can be attached to the basic unit to
indicate this increase. Similarly, another set of prefixes can be
utilized to indicate decreasing orders of magnitude. By combining
the prefixes with
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scientific units, as specified in the SI System, a considerably
simplified and consistent notation system results. This system is
outlined in the table below.
1024 yotta (Y), from Greek of Latin octo (eight) 1021 zetta (Z),
from Latin septem (seven) 1018 exa (F), from Greek hex (six) 1015
peta (P), from Greek pente (five) 1012 tera (T), from Greek teras
(monster) 109 giga (G), from Greek gigas (giant) 106 mega (M), from
Greek megas (large) 103 kilo (k), from Greek chilioi (thousand) 102
hecto (h), from Greek hekaton (hundred) 101 deka or deca (da), from
Greek deka (ten) 10-1 deki (d), from Latin decimus (tenth) 10-2
centi (c), from Latin centum (hundred) 10-5 milli (m), from Latin
Mille (thousand) 10-6 micro (m), from Latin micro or Greek mikros
(small) 10-9 nano (n), from Latin nanus or Greek nanos (dwarf)
10-12 pico (p), from Spanish pico (a bit) or Italian piccolo
(small) 10-15 femto (f), from Danish-Norwegian femten (fifteen)
10-18 atto (a), from Danish-Norwegian atten (eighteen 10-21 zepto
(z), from Latin zeptem (seven) 10-24 yocco (y), from Greek or Latin
octo (eight)
With the advent of the computer and its accompanying "computerese,"
these prefixes have been adopted in a similar manner. Thus,
everyone knows that a megabyte is one million bytes. And that a
gigabyte is a thousand million bytes or one billion bytes. The use
of this prefix system is so pervasive that the abbreviation system
has been further abbreviated; thus, everybody knows and can respond
appropriately when told that a computer has 10 "gig" of
memory.
Unfortunately, this system of prefixes applied to the computer
situation is not strictly correct. Whereas, the normal scientific
system or metric is based on 10 digits, called a decimal system, in
computer work a binary system based on a two-digit code is
employed. Therefore, a "kilo" in the binary computer system is
actually 1,024 instead of 1,000 (2 to the 10th power).
Consequently, the use of the normal metric system prefix is
actually incorrect when applied to the computer binary
system.
Thus lacking in exactness, two major organizations have adopted new
numerical prefixes for numbers in the computer binary system. The
International Electro-Technical Commission (IEC) is responsible for
international standards for electronic technologies. With
considerable imput from the National Institute of Standards and
Technology (NIST) in the United States, a new system has been
adopted for the binary system. Now, to represent exponentially
increasing binary multiples, the IEC has designated kibi (Ki), mebi
(MI), gibi (Gi), tebi (Ti), pebi (Pi) and exbi (Ei). Thus a
kibibyte is 2 to the 10th power or 1,024 bytes; a mebibyte is 2 to
the 20th power, or 1,048,576 bytes; and so forth.
Researchers Toolbox
INJ DEPARTMENTS
STANDARDS DEVELOPMENT FORUM By Chuck Allen, INDA Technical
Director
Test Method Harmonization The buzzword in the area of standardized
test methods is harmonization (making test methods the same in
different parts of the world). As discussed in the last issue of
the INJ, there are any number of standards setting organizations
worldwide. Each organization has its own process for evaluating and
adopting test methods.
One can imagine the technical and political difficulties that could
be associated with identical test methods being adopted by two or
more of the organizations. Having to use different test methods on
the same product, depending on where the product is being sold
geographically, presents difficulties and is costly. Laboratories
may need to purchase and maintain different pieces of equipment or
instruments for testing the same properties of fabrics or products.
To be able to generate reliable and reproducible results, lab
personnel must become familiar and experienced in conducting the
applicable test methods from more than one standard setting
source.
Almost all the standard setting organizations recognize there is
demand for test method harmonization and are investigating ways of
cooperating with each other to reach this difficult goal.
Harmonization In Nonwovens: INDA and EDANA have made test method
harmonization a high priority. INDA publishes its own Standard Test
Method (STM) manual, which contains over 50 test methods for
nonwoven fabrics. Test methods from the STM manual are then moved
through the ASTM process, where the goal is to have them all
eventually approved as ASTM methods, and in the ASTM format. All
the currently adopted ASTM Nonwovens test methods, except for the
geotextile methods, originated as INDA Standard Test Methods.
Likewise, EDANA publishes a test method manual, EDANA Recommen-ded
Test Methods (ERT), containing over 40 methods for testing nonwoven
fabrics. EDANA works through CEN (European Committee for
Standardization) and ISO (International Organization for Standards)
to have their methods recognized as national and international
standards.
The STM and ERT manuals contain many methods that measure the same
properties, but the methods have differences. Due to recent
correlation activities by the two organizations, there are now five
methods that have been harmonized and are identical as contained in
the INDA STM and the EDANA ERT manuals.
Work has begun on the next series of five STM and ERT methods
scheduled for harmonization. INDA, through the Nonwovens
Cooperative Research Center (NCRC) at North Carolina State
University, has put together a harmonization document, which is in
its final editing stages; this document lists the differences
between INDA STM methods and related EDANA, ASTM, TAPPI, ISO and
AATCC methods. This document will soon be available through
INDA.
Global Harmonization: INDA and EDANA are not the only ones involved
in test method harmonization. In late 1998, ASTM and ISO had a
meeting to discuss how they could work together more productively.
As an outcome, ASTM submitted a pilot program for ISO consideration
involving ASTM standards used in the global market where there are
no ISO counterpart standards. ASTM would be the developer and
maintainer of the standards and would actively seek input from ISO
member bodies. The resulting standards would carry an ASTM/ISO
designation.
The proposal has met with approval by the ISO leadership task force
and has been presented to the ISO council for final approval. At
the time of this writing, the outcome is not known, but the vote
was expected to take place at the ISO meeting in
Standard Development Forum
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TANDEC Schedules Conference The ninth annual TANDEC Conference will
be held November 10-12, 1999 at UT Conference Center, The
University of Tennessee, Knoxville, Tennessee, USA and focus on
several exciting areas of the nonwovens industry and
technology:
Marketing Analysis of Nonwovens
Nonwoven Composites and New Applications
New Technology Development and Opportunities
Fundamental Studies in Nonwovens
Attendees will receive concise and practical information on new
nonwoven products and markets, and gain a firm understanding of the
latest technological advances in meltblowing, spunbonding and
related processes.
TANDEC Conferences feature a broad cross section of speakers, who
combine the best aspects of industry, academia and the consulting
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and management will benefit by attending this conference. For
additional conference information please meet us in cyberspace at:
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July. It is important to note that this new system would be on an
individual test method basis. Any communication and cooperation
between ASTM and ISO must be considered a step in the right
direction toward harmonization.
In Europe, CEN is standardizing methods of its member countries,
which include Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the
Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the
United Kingdom. The national standard organizations of the member
countries are bound to implement CEN approved European Standards,
either by publication of an identical text or by endorsement, and
conflicting national standards will be withdrawn within a given
time period. This will result in harmonizing test methods used
within all the CEN countries.
As can be seen, test method harmonization activities are taking
place around the world and are to be applauded. Having global
harmonization of test methods is a noble goal that will take lots
of work and even then may not be accomplished in all areas. When
asked, "Is achieving a single standard practical?" Sergio Mazza,
president of ANSI replied, "Sometimes yes, sometimes no. To try to
answer this question out of the context of a specific application
is completely pointless. In every sector, and sometimes in every
instance within a given sector, you're going to get a different
answer. I do believe you can make a general statement of principle
that you would rather have fewer than more standards, that you want
to minimize duplication, that you want to minimize conflict, but in
many circumstances you can't eliminate duplication and conflict.
You're dealing with different technical infrastructures, or
different regulatory infrastructures, in each sector, and in
different parts of the world. The challenges are demanding and the
goals are worthwhile. Globalization is not a fad. It is here to
stay and there is a need and desire for global test method
harmonization. "
FORMALDEHYDE TEST METHOD EVALUATION FOR NONWOVEN PRODUCTS
Industry Collection Developmement Specific Interference Range
Instrument Ease Time (ppm) AATCC Textile Water Nash Yes Yes 10-3500
Spectrom. Easy Many/day Japanese Japan Water Nash Yes Yes 10-3500
Spectrom. Easy Many/day HPLC ASTM N/A HPLC Yes No >0.05 HPLC
Med. Many/day Tube Furnace UF/Glass Air/Temp. DNPH/HPLC Yes No
>0.05 HPLC Med. 10-15/day Chamber Wood Air/Temp. ? (Yes) (No)
HPLC Med. Limited Humidity Head/Space Chemical Air/Temp GC/MS Yes
No >25 GC/MS Med. 8-10/day GC/MS Hard
Formaldehyde Measurements Considerable effort has been focused on
formaldehyde, formaldehyde content, formaldehyde analysis and
related problems over the past several years. Many concrete and
expensive steps have been taken by the Nonwovens industry to ensure
compliance with a vast array of regulations.
One of the most positive and helpful activities in this regard has
been the TAPPI Binders and Additives Committee work directed
Standard Development Forum
ASSOCIATION FORUM
Oil Spill Cleanup Standards Like many complex activities,
techniques for handling oil spills have been spur-of-the-moment and
highly empirical. The experience of the last 10 years has provided
some useful guidelines in dealing with these calamities, but the
technology and procedures are far from being well established. To
assist in moving toward a more rational approach to remediating the
oil spills and related incidents, the American Society for Testing
Materials (ASTM) has initiated an effort to develop oil spill
cleanup standards. To that end, ASTM is requesting assistance in
developing new standards for shoreline oil spill cleanup and
restoration.
Members of oil spill cleanup cooperatives, response teams, oil
spill removal organizations, oil companies and others are invited
to provide input for develop of these guidelines. This project is
under the chairmanship of Dr. Dick Lessard, who is Oil Spill
Technology Coordinator for Exxon Research and Engineering.
Additional standards are also being prepared for subcommittee
review, including the selection of the appropriate shoreline
cleaning techniques and the classification of shoreline types,
along with definition and delineation of cleanup materials.
Comments in regards to these and other shoreline cleanup standards
are also invited.
In view of the fact that meltblown oil sorbants constitute one of
the major resources for this activity, a significant contribution
from this segment of the nonwovens industry is expected. For
further information or to participate in the preparation of these
standards, the ASTM contact is Robyn Zelmo, 610-832-9717; Fax:
610-832-9666; rzelmo@astm.org.
Cellulose Aging Study An interesting research project has been
initiated by The American Society for Testing and Materials (ASTM).
This will involve a century-long study of the effects of natural
aging on printing and writing papers. A total of 15 experimental
paper types will be stored in volume form by 10 North America
universities and government agencies. Normal storage conditions as
encountered in a typical library stack will be involved. Samples
will be withdrawn from the specimens at various time intervals to
follow the changes with time. A century may seem like a long time
to wait for results, but it was decided that accelerated aging
studies need to be cross-checked
toward the formaldehyde problem. This committee has carried out an
aggressive program focused on developing useful facts and
technology, while dispelling myths and bias. Status reports of this
effort were provided in 1995 and the results of a Round Robin
testing exercise were provided in 1996.
This committee recently completed a major phase of their work and
has provided a definitive status report on the extensive effort
expended. This report was circulated as a separate paper at the
recent TAPPI Technical Conference (March, 1999), although it was
not presented verbally. This summary report was prepared by the
three leaders of the Sub-committee efforts: Michele Mlynar (Rohm
and Haas Company); Tom McNeal (Borden, Inc.) and S.J. Wolfersberger
(Owens Corning Fiberglas). However, because of the seminal nature
of the report, wider circulation is certainly justified.
What follows is an abstract of this report, prepared to provide
insight into the essentials and conclusions of the report.
The objective of the "Formaldehyde Testing Task Force" was to
review available methods for the measurement of formaldehyde for
nonwovens, and to agree on industry measurement standard. The
committee identified three areas for formaldehyde measurements
related to the nonwoven manufacturing process:
Binders: water-based emulsions, phenol-formaldehyde resins,
melamine-formaldehyde resins, and urea-formaldehyde resins.
Stack Emissions: ducts, ventilation systems, venting stacks and
other process sources.
Nonwoven Products: formaldehyde content, evolution from disposable,
durable and industrial nonwoven products.
Each area was assigned to a committee which reviewed different test
methods used by various segment of the industry. These various test
methods were evaluated by establishing test criteria and comparing
the different methods against these criteria. This report
summarizes the formaldehyde test methods evaluated for these three
different industry segments.
The committee found that a single method cannot be recommended for
each industry segment, but that several methods can often be
considered for each segment. This report can be summarized as
follows:
Binders: For water-based emulsions, the ASTM Method (#PS-94-4/#D
5910-96) and the AC Method (#AC-7) were examined. The ASTM method
has been approved by ASTM and other groups, performs very well, and
can be recommended without further evaluation. It is somewhat more
complex and more expensive. The AC Method is limited to low pH
emulsions. The ASTM Method is preferred.
Phenol-Formaldehyde resins were evaluated by three methods (ISO
#9397; #IR-038-05; #M2221.2), all of which use the same analysis
mechanism. The methods differ by endpoint pH determination method,
inclusion of calibration or blank procedures, and certification.
All three methods are more or less equivalent in their results. The
ISO (International Standards Organization) Method has industry
certification and is the basic recommendation..
Melamine-Formaldehyde resins were only analyzed by the Method
Standard Development Forum
with actual experience. However, the researchers who are initiating
the project will not be waiting around for the results
(#ADCH-0188). This method was selected as the resin has a high pH
and requires initial neutralization, which is provided for in the
method. This method is very similar to the urea-formaldehyde
method, after the neutralization step. It is considered to be quite
comparable to the UF methods. It provides satisfactory
results.
Urea-Formaldehyde resins were subjected to four test methods
(#ADCH-0184; #M2221.1; #ACDH-0185; A.P.#32), all of which were
based on the same chemistry. Because of the possibility of unwanted
hydrolysis of the resin, the methods are rather sensitive to
operator technique. All four variations are considered valid and
are quite comparable.
Recommendations for using the methods studied are provided.
Suggestions on calibrating the analysis, potential sources of error
and variation, an indication of precision, etc. are offered for
some of the methods.
Stack Emissions: In this category, five test methods were reviewed,
but no recommendations were made, as no Round Robin tests have been
conducted so far.
The analytical methods considered included the following:
Chromotrophic Acid: Samples are collected in impingers, usually
with aqueous 1% sodium bisulfite as the impinger collection
solution. Normally, an EPA Method 5 train is used with a heated
filter and probe ahead of the impinger sampling train. Impinger
samples are analyzed by the chromotropic acid method, forming a
purple color proportional to formaldehyde concentration, which is
measured in a spectrophotometer at a wavelength of 580 nm.
Dinitrophenylhydrazine Method: Samples are collected in impingers,
usually using saturated 2,4,DNPH (dinitrophenylhydrazine) in
aqueous 2 NHCl as the impinger collection solution. Normally, an
EPA Method 5 train is used with a heated filter and probe ahead of
the impinger sampling train. Impinger samples are extracted with
methylene chloride, and the extracts are analyzed by liquid
chromatography. The chromatographic separation is usually optimized
so that a variety of aldehydes and ketones can be determined in a
single analysis.
Pararosaniline: Samples are collected in impingers, using
high-purity water as the impinger collection solution. Normally, an
EPA Method 5 train is used (without a filter) and probe ahead of
the impinger sampling train. Impinger samples are analyzed by the
pararosaniline method, forming a purple color proportional to
formaldehyde concentration, which is measured in a
spectrophotometer at a wavelength of 570 nm.
Fourier-Transform Infrared Spectro-scopy: Measurements are made
directly on the stack gas, by passing an infrared beam across the
stack (in-situ), or by extracting a portion of the gas into a cell.
High-resolution infrared spectra are obtained, and interfering
spectral features (from compounds such as water, carbon dioxide,
etc.) are subtracted from the spectra. The amount of formaldehyde
can then be calculated by comparison to a stored reference spectrum
of a formaldehyde standard.
Acetylacetone: Samples are collected in impingers, using
high-purity water or 10% methanol in water as the impinger
collection solution. Normally, an EPA Method 5 train is used with
heated filter and probe ahead of the impinger sampling train.
Impinger samples are analyzed by the acetylacetone method, forming
a yellow color proportional to formaldehyde concentration, which is
measured at a wavelength of 412 nm.
It is suggested that Round Robin testing is appropriate in this
sector, along with a further study of Head Space/Gas
Chromotography/Mass Spectography Detection (GC/MS) Method.
Nonwoven Products: In this industry sector, a total of 10 test
methods were submitted and reviewed, including the following:
AATCC Sealed Jar Test #112-1993: This method is used for nonwovens
and other textiles employed in the industry. It measures the free
formaldehyde plus some of the bound formaldehyde in a fabric.
Tube Furnace Method: This method is specific for urea-formaldehyde
and glass mat products. With HPLC development properly carried out,
it is very specific for formaldehyde.
Japanese Ministry Ordinance Article #4, Legislation #112, 1973:
This method measures the free formaldehyde in a sample, but under
some conditions can generate analyte from bound formaldehyde. The
method is required for any imports into Japan. It is also growing
in use as a standard method for the baby wipe industry.
Chamber Test: This method is used by the wool industry to measure
the formaldehyde emission from wool dust particles. It is a dynamic
test that could be adapted for nonwovens, but required further
development work.
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Head Space/GC/MS: Further work is required to assess the value of
this method in comparison to other methods.
LC Pre-Derivatization (High Pressure Liquid Chromatography,
HPLC/Nash): This method uses high pressure liquid chromatography to
separate the free formaldehyde from the other components, followed
by post column derivatization with Nash reagent and visible
absorbence detection. It is a method under development, so is not
appropriate at this time for a standard.
MITI JIS-L1041-1960: This method is the forerunner of the present
Japanese Law 112-1993 and has been replaced by the more recent
method. It is not recommended.
KCN Method: This method was not recommended and is not being
further studied.
Shirley Institute Test: This test was developed many years ago; it
is not recommended and will not receive further work.
The first six method were subjected to further evaluation and rated
for characteristics and appropriateness, as summarized above.
It is hoped that individuals who have a definite interest in this
report and topic will pursue the matter further. For those who
would like to learn more about this project, or make comments on
the report and the committee's activities, or to study the material
further, a copy of the report can be obtained from Michele Mlynar,
Specialty Polymers Group Leader, Fiber and Textile Polymers, Rohm
and Haas, Research Laboratories, 727 Norristown Road, P.O. Box 904,
Spring House, PA 19477; 215-641-7107; Fax: 215-619-1622;
michele_f_mlynar@rohmhaas.com
Your comments and suggestions regarding this department and the
area of standards development are welcome, please respond to Chuck
Allen, callen@inda.org; INDA, P.O. Box 1288, Cary, N.C. 27513;
919-233-1210, ext. 114, Fax 919-233-1282.
The editors wish to express their appreciation to Mr. Allen for
agreeing to develop and edit this column.
—INJ
Return to International Nonwovens Journal Home Page & Table of
Contents
Standard Development Forum
INJ DEPARTMENTS
PATENT REVIEW Spunbond Fabrics from Nylon and Polyethylene
Continuous filament nylon spunbond fabrics are a special category
within the spunbond nonwoven classification. The fabrics are
produced by a process in which molten nylon-66 resin is extruded
into continuous filaments, the filaments are attenuated and drawn
pneumatically, and then deposited onto a collection surface to form
a continuous filament web. These filaments are bonded together to
produce a strong, coherent fabric.
Filament bonding in the case of nylon can be accomplished either
thermally or chemically. Thermal bonding is accomplished by passing
the web of filaments through the nip of a pair of heated calender
rolls; one of the rolls carries a pattern of elevated points
providing discontinuous bond sites resulting from the heat and
pressure of the calender points.
Chemical or autogenic bonding can also be employed; in this
operation, the web of filaments is transported to a chemical
bonding station or a "gas house," which exposes the filaments to a
mixture of hydrogen chloride gas and water vapor. The water vapor
enhances the penetration of the hydrogen chloride gas into the
filaments; the mixture causes the filaments to become tacky and
thus amenable to autogenic bonding. Upon leaving the bonding
station, the web passes between rolls which compact and bond the
softened filaments in the web. Adequate bonding is necessary to
minimize fabric fuzzing (that is, the presence of unbonded
filaments) and to impart good strength properties to the fabric.
Autogenic bonding has been especially used in forming spunbond
nylon- 66 industrial fabrics.
Whether bonded by the intermittent thermobond process or autogenic
bonding agents, these nonwoven fabrics tend to be somewhat stiff
and boardy, as produced. This arises from the fact that even with
point bonded fabrics, it is frequently difficult or even impossible
to strictly limit bonding to the desired points. Filaments that are
not compressed by the embossed points are still subject to the heat
of the calender and tend to form weak, secondary or "tack" bonds of
the filaments outside the desired bond areas. In a similar manner
in autogenic bonding, secondary or tack bonds can form between
filaments where the area of contact is very limited, giving weak
bonds.
In both processes, these weak, secondary bonds promote fabric
stiffness, but contribute little to fabric strength and integrity.
Consequently, it has been found beneficial to subject such nonwoven
fabrics to a
Patent Review
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softening process. This is generally done by subjecting the fabric
to mechanical stress. Such treatments are believed to effect
softening primarily by breaking the weak, secondary tack bonds,
which can be broken without breaking the primary point bonds or
those bonds intentionally created to foster strength.
The mechanical stress methods for softening may include the process
of washing the fabric, drawing the fabric under tension over
sharply angled surface such as a knife blade, stretching the
fabric, twisting, crumpling or subjecting the fabric to various
combinations of such treatments. The fabrics can also be softened
by impinging the fabric with high pressure fluid jets. While these
mechanical stress methods are relatively effective, they create
many problems, especially in view of a desire to maintain a direct,
continuous process.
This patent describes a process for obtaining a soft, yet strong
nylon spunbond fabric without the problems associated with the
mechanical stress softening steps. This involves the addition of a
small amount of polyethylene polymer to the nylon feedstock prior
to extrusion. The addition of the polyethylene to the nylon resin
enhances specific properties such as softness. The use of
polyethylene also lowers the cost of production and eases further
downstream processing, such as bonding to other fabrics or to
itself.
The improved nylon spunbond fabric is obtained by adding a small
amount of polyethyl