APPAREL VIEWS / DECEMBER 201164

Dyeable polypropylene fibre is a revolutionary new

fibre for the apparel market created by

FibreVisions, one of the world’s largest producers of

polyolefin staple fibres. CoolVisions™ is the industry’s

premier disperse-dyeable polypropylene fibre, created

to address the needs of the manufacturer and the

desires of the consumer.

Dyeable polypropylene fibres offer a vast array of inherent

benefits and properties of traditional polypropylene

fibres: Lightweight and comfortable, with moisture

management, durability, thermal insulation and stain

resistance. Unlike traditional polypropylene fibre, this

new fibre is dyeable with disperse dyes, and its unique

design results in a soft hand.

Conventional polypropylene fibre

In contrast to other fibres, conventional polypropylene

fibres cannot be dyed. Instead, the colour has to be

imparted at the fibre extrusion step through mass

colouration or solution dyeing. The process involves

adding a relatively thermally stable pigment colour

during the melt spinning of the fibre. The pigments

used are not usually miscible with polypropylene.

Thus, the pigments are present as discrete particles

in the fibre, and the colour imparted becomes

permanent in the fibre.

While this has the benefit of very good colourfastness,

there are two significant disadvantages. The first is

that introducing new colours involves a relatively

complex colour-matching step. The second is the

absence of greige goods to be dyed. This means

that relatively large lots of fibre are made for every

new colour, and the time required going from a

Application of contemporary fibres in apparels

new colour concept to the final fabric or garment

can be long.

Ideally, it should have a dyeing profile similar to or

compatible with large-volume fibres such as

polyester, nylon or cotton, so that it is compatible

with the dyeing and related processes that are already

well-established. Furthermore, it should not change

the essential benefits of polypropylene fibres

presented in Table 1 especially its low density and its

low surface energy. There have been several attempts

to make dyeable polypropylene fibres, but they have

not been successful because the resulting product

did not meet these criteria.

Technology of dyeable

polypropylene fibre

FiberVisions has developed a revolutionary new

polypropylene fibre, dyeable polypropylene fibre, which

meets the needs of facile dyeing and polypropylene

fibre characteristics by incorporating an additive within

the polypropylene fibre. The fibre can be dyed using

conventional disperse dyes in a manner similar to

that used for polyester fibres.

As discussed, dyeable polypropylene fibres contain

an additive that acts as a dye receptor. The additive

is present in the fibres as small domains into which

the disperse dyes dissolve during the dyeing process.

At dyeing temperatures greater than the boiling point

of water, the disperse dyes diffuse readily through the

polypropylene fibre into the encapsulated domains of

the additive. Under actual garment use conditions -

which include much lower temperatures - the diffusion

of the disperse dyes back out of the fibre is greatly

diminished, resulting in good colourfastness. As with

polyester fibres, high-energy disperse dyes should be

used to obtain optimum colourfastness.

The approach of encapsulating the additive within

the polypropylene fibre has many benefits. The surface

of the fibre is essentially unchanged, resulting in

excellent aqueous stain resistance and low water

absorption. The polypropylene fibre also serves to

protect the dyes from chemicals such as chlorine,

resulting in excellent bleach fastness.

Since the ability to dye the polypropylene fibre is imparted

by the incorporation of an additive, the level of the additive

affects the depth of shade. This has a couple of benefits;

the additive level can be controlled quite well, resulting

in reduced shade sensitivity to processing conditions. In

addition, the level can be intentionally changed to produce

fibres that dye to different depths, thereby offering an

additional styling tool.

Dyeable polypropylene fibre

characteristics

Currently, dyeable polypropylene fibres are available

in form of staple fibre for ring spinning. The yarn

spinning, knitting and weaving procedures for

dyeable polypropylene can be done in a similar

manner to current pigmented polypropylene

products. The dyeing procedure mirrors the same

steps used for disperse dyeing polyester. Lower

temperatures can be used for dyeing and are required

for the finishing process. Dyeable polypropylene

fibres can easily be blended with wool, cotton,

cellulosic or man-made fibres.

Dyeable polypropylene fibre

Polypropylene fibres possess a number of attractive properties when compared to other fibres used in apparel.

Despite of desirable properties, polypropylene fibres traditionally have suffered from a major drawback that has

limited its usage in textile apparel applications and the main reason behind this was dyeing. Polypropylene can now

easily be dyed with disperse dyes in aqueous media in a standard industry process

APPAREL VIEWS / DECEMBER 2011 65

Comparison of polypropylene fibre

with other fibres

Lightweight and comfortable

Polypropylene fibres are among the lightest in weight

of all available commercial fibres. The increased

number of polypropylene fibres per kilogram of fabric

offers added value as compared to many other fibres,

resulting in improved coverage for the same weight

range or equal coverage in lighter-weight fabrics for

comfortable garments. In addition, dyeable

polypropylene fibres are inherently softer than

traditional polypropylene fibres, resulting in greater

comfort. This combination of attributes makes

garments made from these new fibres inherently easy

care, easy wear.

Thermal insulation

Dyeable polypropylene fibres provide better insulation

than most other fibres. Insulation power is the ability

to insulate against heat conduction through the fibre,

relative to the insulation power of air. In cold weather,

the greater the insulation power, the greater warmth

wearer will feel in the fabrics.

2

1.6

1.2

0.8

0.4

0

Density (g/cm 3)

Polypro

pylen

e

Polyes

ter

Polyam

ideAcry

lic

Cotton

Wool

Silk

Moisture management

Dyeable polypropylene fibres out perform all other

dyeable fibres in low-moisture-absorption tests. In

addition, garments made from polypropylene tend to

have a high moisture-vapour-transmission providing

the industry ’s fastest drying garments. This is

important in comfort, especially when one wants the

skin to stay cool and dry. The mechanical properties

of polypropylene fibres are not affected when the fabric

is wet an inherent advantage compared to fibres like

rayon, which can lose strength substantially.

As with traditional polypropylene, dyeable

polypropylene offers excellent chemical resistance

and aqueous stain resistance. Bleach and other

household cleaning chemicals do not affect the fibres,

which also are not attacked by microbial organisms

such as mold, mildew and bacteria.

Polypropylene Polyester Polyamide Acrylic Cotton Wool Silk

Stain resistance

Advantages of dyeable

polypropylene fibre

The fibres feature a wide array of inherent benefits

and properties including:

• Light weight and comfort

• Cottony softness

• Easy care, easy wears

• Moisture management

• Durability

• Breathability

• Thermal insulation

• Stain resistance

Brands using dyeable polypropylene

fibre for their products

Today global brands such as Terramar and The North

Face are using dyeable polypropylene fibres in their

products. The North Face flannel Tekware shirts for

men and women were introduced at outdoor retailer

winter market last year itself. The North Face garments

are blends of dyeable polypropylene fibres and cotton.

15

Polypropylene

10

5

0Polyester Polyamide Acrylic Cotton Wool Silk

Moisture Regain percentagePolypropylene Polyester Polyamide Acrylic Cotton Wool Silk

FairFair

Good

Excellent

Good GoodGood

Chlorine bleachresistance

Polypropylene Polyester Polyamide Acrylic Cotton Wool Silk

0.2

0.15

0.1

0.05

0

Insulation power(Air = 1)

Polypropylene Polyester Polyamide Acrylic Cotton Wool Silk

FairFairFairFair

Good

Excellent Excellent Durability

Chlorine bleach resistance

Bleach and other household cleaning chemicals do

not affect dyeable polypropylene fibres.

Caring for dyeable polypropylene

fibre

Dyeable polypropylene fibre dries very quickly. The

garment made with dyeable polypropylene can be

machine wash in cold water. These fabrics need to

lay flat to dry or tumble dry on low permanent press

cycle. Cool iron can be used, if needed. Dry cleaning is

not required for the garment made by dyeable

polypropylene fibre.

Environmental benefits of dyeable

polypropylene fibre

Polypropylene is enjoying a revival in the apparel market

with today’s increased interest in “green” products

and the advent of dyeability. Polypropylene has a strong

sustainability platform. To begin, polypropylene has the

best carbon footprint in the category of synthetics. As

compared to all other the major synthetic fibres,

polyolefins are the only ones which begin as a co-

product, meaning lower greenhouse gas emissions and

lower energy use than other fibre resins. The fibre

manufacturing process of polypropylene has a low

impact on the environment as there is no toxic waste,

low emissions, and no fluorocarbons, or halogens. The

environmental impact is also seen at the consumer

level, with reduced energy use for drying of garments

and high potential for recycling.

Conclusion

Fashion designers and textile manufacturers are facing

increasing demands for style, sophistication and above

all, performance. They are trying delivering everything

from the simplest everyday garments to the most

glamorous fashions, and they also have an ambition to

create more value-added products through innovation

and stronger branding. The challenge now is to go

beyond the basics and respond quickly to market needs.

Invention of dyeable polypropylene fibre provides

brilliant colour shades to meet fast-moving market

trends by providing new styling options for apparel.

Dyeable polypropylene fibre is well-suited for any

lifestyle as it is easy care, easy wear. Further, dyeable

polypropylene fibres also offers immense production

possibilities where manufacturers benefit from

increasing their operational effectiveness, reducing

the inventory of coloured yarns, streamlining the

production process and obvious better margins.

Retailers are also getting benefited because of product

differentiation, speed to market and most importantly

consumer satisfaction

Durable

Dyeable polypropylene fibres have excellent

toughness and abrasion resistance resulting in

durable products that wear longer than most

other fibres.

Stain resistance

Stain resistance is one of the superior advantages of

dyeable polypropylene fibres. Polypropylene fibre is

inherently resistant to water-based stains.

By Vasant R Kothari, Assistant Professor, NIFT, Bangalore

(Author can be contacted @ www.vasantkothari.com)

Perspiration escapesas water vaporthrough microscopicpores. These poresare too small for waterdroplets to penetrate.