UV CURING BASICSBroadband & LED Technology and Applications by Heraeus Noblelight
HOUSEKEEPING
Webinar duration: presentation: 30-40 min with additional 20 min for Q&A
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Online Session: UV Curing Basics / Broadband & LED Technology and Applications
AGENDA
Introduction to Heraeus and Heraeus NoblelightPrinciples of UV curing: chemistry, process, UV lamp systemsBenefits of UV LEDs: explore customer cases Q&A session
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
AGENDA
Introduction to Heraeus and Heraeus NoblelightPrinciples of UV curing: chemistry, process, UV lamp systemsBenefits of UV LEDs: explore customer cases Q&A session
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
HERAEUS – A GLOBALLY SUCCESSFUL PORTFOLIO COMPANY
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
EMPLOYEES2
14,900
R&D EXPENDITURES17%
Listed in FORTUNE GLOBAL 500
TOTAL REVENUE
20.3 bn €
1 based on revenues excl. Precious Metals 2 incl. contract employees
25%
17%America
REVENUE EXCL. PRECIOUS METALS2018 BY REGION
EMPLOYEES2018 BY REGION
19%
15%
Rest ofEurope
11%
39%Germany
2%
1%
Africa /Australia
43%
28%Asia
More thanSITESin COUNTRIES40
100
GLOBAL BUSINESS UNITS
Market-oriented distributionin 11
TOP 10 FAMILY-OWNED COMPANIES
in Germany
6/22/20206
› 10+ years of experience in UV LED mechanical & electrical engineering, optical & thermal simulations, photon management and production.
› Manufactured in Germany in fully automated state-of-the-art production lines. In-house qualification of chips delivers better and more consistent quality. Tests include electrical and thermal connections on the chips.
› Value Chain control with own production of patented primary optics, of silver paste and gold wire. Full traceability of assembled material, inline process parameters, final inspection measurement data
› Independent measurement laboratory accredited as a test laboratory and local Application Competence Centers (ACCs) for in-house trials with the support of experienced chemists.
HERAEUS UV LED
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/20207
AGENDA
Introduction to Heraeus and Heraeus NoblelightPrinciples of UV curing: chemistry, process, UV lamp systemsBenefits of UV LEDs: explore customer cases Q&A session
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
› UV curing is based on a photochemical reaction› Fast, immediate process due to UV irradiation› No outgassing and no loss of coating thickness› Solvent-free› Free radical polymerization process is typical (shown)
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
SUBSTRATE
POLYMERCOATINGLAYER
SOLID
OLIGOMER, MONOMER, PHOTOINITIATOR
SUBSTRATE
UV LIGHT
COATINGLAYER
LIQUID
Polymer chains are built up and crosslinked into a 3-dimensional network using a photoinitiated polymerization process.Within a split second, the cross-linked system is dry and abrasion-proof and can immediately be processed in the next production step.
6/22/20209
UV CURING PROCESS
APPLICATION AND INDUSTRIES FOR UV CURING
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
AUTOMOTIVE INDUSTRY
COATING OF SURFACES
PRINTING INDUSTRY (DIGITAL, FLEXO,
SCREEN PRINTING)
METAL DECORATING& BOTTOM RIM
COATING
ELECTRONICS COATINGS & ASSEMBLY
GLASS DECORATING FIBER OPTICS
ADHESIVE AND PAINT CURING
6/22/202010
FACTORS THAT INFLUENCE THE UV PROCESS
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
› Spectral distribution› Irradiance and energy› Energy distribution› IR-radiation
UV lamp system
› Chemical components› Spectral absorption› Spectral reaction› Optical thickness
Formulation
› Dispensing method› Layer thickness› Process speed› Substrate
Product
6/22/202011
COMPONENTS OF A UV CURABLE FORMULATION
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Photoinitiator
Additives
Monomers
Oligomers
Molecules that absorb UV light and initiate polymerisation process
Pigments, flow control agents, matting agents, fillers etc
Molecules crosslink with each other &with oligomers.Viscosity reduction. Contribute to coating performance characteristics
High molecular weight molecules with reactive sites. Key coating performance characteristics.
6/22/202012
PHOTOINITIATORS
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202013
Initiation reaction
Polymerization process
M M●●
OO
MM
MO
● ●
Initiation
Propagation
Photoinitiator
ORー
O●
R●
Initiation species generation
photons
Hg lamp UV LED lampPhotochemical process
PHOTOINITIATORS
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202014
Surface cure Through cure and adhesion
Absorbance of 4 different photo initiators
KEY FEATURES OF A UV LAMP SYSTEM
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Irradiance, W/cm2
Profile of radiant power arriving at a surface, in a specific waveband Usually peak irradiance is reported
Energy, J/cm2
Spectral output
6/22/202015
Distance or time
Area under curve is proportional to total energy
Irradiance Profile(Not a function of speed)
Peak
1 2 3 4 5 6 7 8 9 10 11
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
PEAK IRRADIANCE & TOTAL ENERGY
6/22/202016
0,0
0,5
1,0
1,5
2,0
2,5
3,0
50 75 100 125 150 175
Irrad
ianc
e [W
/cm
²]
Distance from lamp [mm]
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
IRRADIANCE & DISTANCE TO THE SURFACE
6/22/202017
Semray® UV4000 UV LED lampMicrowave powered UV lamp, 240W/cm H bulb
KEY FEATURES OF A UV LAMP SYSTEM
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Irradiance, W/cm2
Profile of radiant power arriving at a surface, in a specific waveband Usually peak irradiance is reported
Energy, J/cm2
Total energy arriving at a surface in a given timeTime integral of the irradiance profileInverse of speed
Spectral output
6/22/202018
Distance or time
Area under curve is proportional to total energy
Irradiance Profile(Not a function of speed)
Peak
1 2 3 4 5 6 7 8 9 10 11
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
PEAK IRRADIANCE & TOTAL ENERGY
6/22/202019
KEY FEATURES OF A UV LAMP SYSTEM
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Irradiance, W/cm2
Profile of radiant power arriving at a surface, in a specific waveband Usually peak irradiance is reported
Energy, J/cm2
Total energy arriving at a surface in a given timeTime integral of the irradiance profileInverse of speed
Spectral outputRelative radiant output versus wavelength (nm)
6/22/202020
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Spectra of different microwave-powered bulbs
6/22/202021
UV SPECTRAL OUTPUT
SPECTRAL OUTPUT
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202022
Semray® UV4000 series output wavelength
PENETRATION OF MATERIAL BY UV RADIATION
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
UV Coating
Substrate
1- 60µm
200 – 280 nmHigh energy UV lightfor top surface curing
315 – 380 nmUV closest to the visible spectrum
to cure deep layers, e.g. highly pigmented lacquers and thick varnish layers
280 – 315 nmLonger wavelength for
deeper penetration
UVC UVB UVA Optical thickness of a curable film determines to what extent irradiance will affect depth of cure and adhesion.
Spectral absorbance of coatings will affect which wavelengths will more effectively penetrate and how the irradiance level will achieve depth of cure.
Absorption spectrum of the photoinitiator will determine the wavelength responsivity.
6/22/202023
› Oxygen is present on the surface & dissolved in the bulk of the formulation
› Reduces the efficiency of photoinitiators› Formation of peroxy radicals reduces
polymerization process› Variation in double bond conversion through
the depth of coating
OXYGEN INHIBITION - CHALLENGE FOR SURFACE CURE WITH UV LED
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202024
Challenge – lack of short wavelength output › Absorbed in top layers of coatings› Overcome problems caused by oxygen inhibition
› Tacky surface
Challenge – lack of short wavelength output › Optimise formulation› Cure in inert atmosphere › Combine with other UV lamps, e.g. med. pressure Hg › Ensure high UV irradiance reaches the coating
surface› Higher power UV LED lamp
› Increase concentration of initiating & propagating radicals
UV LED CHALLENGES – WORKING DISTANCE
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202025
Working distance› As distance increases, intensity of UV decreases› Reduces cure speed of the coating› Some applications may not be possible:
› Intensity/energy reaching coating is too low› Physically need lamps to be further away
› Optimise micro-optics within the UV LED lamp› Ensure minimum stray light
› Micro-optics reduce exit angle from 120° to 60°› 30% higher UV energy reaches the substrate › Possibility to cure coatings at larger or variable
working distances
PHOTOPOLYMERISATION WITH UV BROAD BAND LAMP & UV LED LAMP
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202026
Similarities› Principle of UV curing› Photopolymerization process› Used for both free radical & cationic curing› Components UV formulation› UV curing system design considerations› Process & application development process
Differences› Reduced heat delivered to coating during curing› No ozone generation› Lack of short wavelength UV impacts surface cure› Restricted photoinitiator choice matching narrow
band LED emission
AGENDA
Introduction to Heraeus and Heraeus NoblelightPrinciples of UV curing: chemistry, process, UV lamp systemsBenefits of UV LEDs: explore customer cases Q&A session
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
DIFFERENT SOLUTIONS FOR DIFFERENT APPLICATIONS
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202028
› Irradiance values & Power class› Optical concepts› Different cooling concepts› Complete UV LED systems
Medium Power Class
High End Class
High Power Class
UV5000 Series
UV7000 Series
UV4000 Series
60+
40-60
20-40Pinning Class
UV2000 Series<20
CASE STUDY – NANO IMPRINT
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Request› UV irradiance adjustment for
different line speeds / coating compositions
› Homogeneity and flexibility for different substrate widths
› High power at 365 nm› Oxygen inhibition
Development› Joint trials at Heraeus ACC
(lab and demo center)› Process validation tests› Machine integration meetings
Solution› UV4000 BP-16 with Semray
UV4003 365 nm [primary optics]› Interface control integration for
automatic or manual control of irradiation width and UV irradiance
› High power for 365 nm with 13 W/cm2 at the emission window
› Press the coating on the roll to exclude oxygen
6/22/202029
CASE STUDY – BOTTLE PRINTING
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Request › Replace outdated mercury system› Print speed:
83 ft/min / 25 m/min› Curing distance:
3 inches / 76 mm› Maintain production speed of
30 to 60 bottles per min.
Development› Trials at Heraeus lab and OEM
demo center› Customer validation tests› Machine integration meetings
Solution› Flexible LED installation at
demo center› Exchange of wavelength in
seconds› Flexibility of integration› 75% Energy savings
6/22/202030
ENERGY SAVINGS ESTIMATIONS
Online Session: UV Curing Basics / Broadband & LED Technology and Applications6/22/202031
$-
$10.000
$20.000
$30.000
$40.000
$50.000
$60.000
$70.000
$80.000
0 0,2 0,4 0,6 0,8 1 1,2
USD
Time (years)
Electrical Cost Comparison (kWh)
Hg lamp LED
CASE STUDY – CABLE MARKING
Online Session: UV Curing Basics / Broadband & LED Technology and Applications
Request › Develop a powerful air-cooled small
format LED system for curing at marking speeds
› Print speed: 650 ft/min - 200 m/min › Curing distance: 1 inch – 25 mm› Support both side curing
Development› Trials at OEM due to project
confidentiality› First initial tests done with Heraeus
LED Altair› Semray 4003 introduced six months
later› Customer validation tests
Solution› Compact LED design › Power modulation adjustable to
line speeds› Cost effective reflective solution› Semray micro optics allow focus
on small footprint
6/22/202032
AGENDA
Introduction to Heraeus and Heraeus NoblelightPrinciples of UV curing: chemistry, process, UV lamp systemsBenefits of UV LEDs: explore customer casesQ&A
Online Session: UV Curing Basics / Broadband & LED Technology and Applications