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6 Name: R. Gary Freelin Title: Group Leader, Radiation Curing Company: Evonik Industries Company Profile: EVONIK Industries AG Annual turn over: 13,4 billion Headquarter(s): Essen, Germany Key Operation(s): Evonik -the creative industrial group from Germany -is one of the world's leading specialty chemicals companies. Number of employees: (2012) Application markets: UV curable silicones for filmic or paper release liner as used in labels, linerless labels, tapes

7 Humidity effects on Label laminates AWA Global Release Liner Industry Conference Denver, March 2015

8 1. TEGO RC Silicones 2. Label laminate and siliconizing on printing presses 3. Requirements to the silicone coating: Stable, low release 4. Release testing and humidity effect 5. Market needs and conclusions

9 1. TEGO RC Silicones 2. Label laminate and siliconizing on printing presses 3. Requirements to the silicone coating: Stable, low release 4. Release testing and humidity effect 5. Market needs and conclusions

10 TEGO RC Silicones When thermal silicones have to give up - TEGO RC Silicones will provide a solution for you! Use of heat-sensitive films PE, PP, PET, PVC Absolute paper lay flat coated craft paper like CCK, PEK Cost reduction down gauging films and papers Environmentally friendly production low energy consuming, no solvents Page 5

11 TEGO RC Silicones Labelstock standard label products, clear-on-clear labels, thermal labels, linerless labels Personal Hygiene diaper tapes, sanitary napkins Building & Insulation membranes, foams, floor covering, sound deadening, bitumen Tapes Others industry, electronics, security, insulation, carpet, envelopes, office thermal transfer printing, over laminating, protective films, process liners, ceramic capacitor Page 6

12 TEGO RC Silicones Free Radical Polymerisation Initiation h ν PI P + I P + C=C P-C-C PI = Photoinitiator Propagation P-C-C + C=C P-C-C-C-C Termination e. g. P-C-C + C-C-P P-C-C-C-C-P Page 7

13 TEGO RC Silicones Established standard today: Standard medium pressure mercury lamps aka arc lamps Compact construction, easy retrofitting Approx. 1.3 m in web direction, less floor space Inerting to less than 50 ppm Well suited for in-line siliconizing Widely used on printing presses Page 8

14 1. TEGO RC Silicones 2. Label laminate and siliconizing on printing presses 3. Requirements to the silicone coating: Stable, low release 4. Release testing and humidity effect 5. Market needs and conclusions

15 Label laminate and siliconizing on printing presses Established siliconizing standards today: 1. Release liner siliconizing at high speed on wide web lines. 2. Tandem coating of silicone and adhesive on medium wide dedicated coating lines. 3. All in one presses, typically 50cm wide: in-line siliconizing hotmelt coating multi color label printing dye cutting, matrix removal and slitting to label size Page 10

16 Label laminate and siliconizing on printing presses Quality requirements of a label laminate: Label Pressure Sensitive Adhesive Substrate Silicone Page 11

17 Label laminate and siliconizing on printing presses Quality requirements of a label laminate: The crucial stages On printing press: Matrix removal dye cutting requires low release without initial spike On label dispenser: No flyers right level of release No release increase over label shelf life Easy label lifting on dispensing edge In final label application: No silicone transfer to the adhesive Page 12

18 1. TEGO RC Silicones 2. Label laminate and siliconizing on printing presses 3. Requirements to the silicone coating: Stable, low release 4. Release testing and humidity effect 5. Market needs and conclusions

19 Requirements to the silicone coating Quality requirements of a label laminate: The silicone layer must provide 1. Low release level, controlled release 2. No initial spike 3. Stable release over label life time Page 14

20 Requirements to the silicone coating Quality requirements of a label laminate: TEGO RC Silicones provide low and stable release over time provided that 1. the degree of cure is right (low O 2 level during UV curing) 2. good coverage of silicone (coater head setting and silicone coat weight) Release 40 C [cn/in] HM PSA trial - 40 C aging Silicone good cured 1 Standard for comparionson 2 Polymer with no diblock 3 SBS Polymer, Tackifier with 1/4 C9 and 3/4 C5 5 Polymer hydrogenated SEBS 6 Tackifier 100% hydrogenated C9 7 Polymer & Tackifier hydrogenated 8 Tackifier contains Rosin Ester 9 Tackifier with 1/4 C9 and 3/4 C5 10 Naphtenic oil Ageing Time 40 C [days] Page 15

21 Requirements to the silicone coating Quality requirements of a label laminate: Good coverage of silicone Test ink e. g. 0.1 % Methylene blue in water One minute contact time with silicone coated surface Cobb tester to hold ink on substrate Only for paper substrates, not for film or polycoated papers Page 16

22 Requirements to the silicone coating Quality requirements of a label laminate: Good coverage of silicone Bad setting of coater head Good setting of coater head Page 17

23 1. TEGO RC Silicones 2. Label laminate and siliconizing on printing presses 3. Requirements to the silicone coating: Stable, low release 4. Release testing and humidity effect 5. Market needs and conclusions

24 Release testing and humidity effect Release measurement is always a combination of silicone adhesive separation and energy dissipation. Silicone adhesive separation Energy for new surface creation Silicone adhesive attractive forces (interface chemistry) Often confused as sole source of release force Mechanical energy dissipation Bulk mechanical response of the non-rigid components Influenced by the test set up and label construction Major contribution especially in easy release Page 19

25 Release testing and humidity effect Mechanical energy dissipation influenced by test set up and label materials. Set up Test humidity Label materials Peel in web direction or across Liner peel or face peel Controlled 50% rh Ambient 20-80% rh Paper or filmic Thick or thin material FINAT FTM1 TLMI Tester Tensile tester 300 mm/min peel 300 in/min peel All speeds 180 peel, free or fixed 180 peel, free or fixed 90 peel possible All angles, very suitable for free 90 peel Page 20

26 Release testing and humidity effect Silicone adhesive separation forces given by adhesive and silicone. Test set up can influence separation force too: Test temperature Contact time Pressure load Controlled 23 C Ambient C 1 minute hours 1 month to 6 month None 70 g/cm² Laminating machine some examples next Page 21

27 Release testing and humidity effect Adhesives develop more tack at higher temperatures Keep test temperature constant Page 22

28 Release testing and humidity effect Different label materials generate different release levels Careful comparing differed label constructions Same release liner and adhesive with different face stock materials. Page 23

29 Release testing and humidity effect Different peel speed can deliver different release Careful comparing FINAT and TLMI values Page 24

30 Release testing and humidity effect Paper has different stiffness in web and across web direction Always test in web direction Page 25

31 Release testing and humidity effect So many influencing effects on release, and now on top the Humidity effect Page 26

32 Release testing and humidity effect Humidity effect 2011/ 2012 Evonik received a lot of customer inquires about unstable release in higher temperature and humid areas. Same inquiry went to many adhesive suppliers. Label material in local warehouses doubled or tripled in release. More difficulties in matrix removal and label dispensing reported. Customers and industry partners suspected bad quality adhesives or silicones? adhesive silicone interaction? Page 27

33 Release testing and humidity effect How to test? Release test in controlled high humidity developed by ETI. Proposal: Laminate storage for 48hrs at 40º C and 75% rh. Humidity effect More controlled procedure with climate chamber used by Evonik. Page 28

34 Release testing and humidity effect Humidity effect Effect is marginally due to higher temperature. Effect is mainly due to high humidity of e.g % rh. Effect is reversible, good release again if storage in normal humidity. Page 29

35 Release testing and humidity effect Humidity effect Effect is due to a change in paper stiffness Humid 75% rh (48h storage/ 40 C) Dry 25% rh (48h storage / 40 C) Release force = 30 cn/in Release force = 14 cn/in Release increase due to higher mechanical energy dissipation No change of adhesive and silicone interaction Page 30

36 Release testing and humidity effect Papers change their properties in humid condition No such effect with filmic materials Page 31

37 Release testing and humidity effect Different papers react differently on humidity Try keep storage and test humidity constant Same release liner and adhesive with different face stock materials. Page 32

38 Release testing and humidity effect Try keep storage and test humidity constant Possible at all? In hot countries with high humidity it may be possible to control conditions in a test room but not during transport and in warehouse. Page 33

39 1. TEGO RC Silicones 2. Label laminate and siliconizing on printing presses 3. Requirements to the silicone coating: Stable, low release 4. Release testing and humidity effect 5. Market needs and conclusions

40 Market needs and conclusions TEGO RC TEGO RC 922 provides a lower release and better anchorage at the same time. Note: Release values are depending on test method FINAT/ TLMI Page 35

41 Market needs and conclusions Pilot Line for UV Siliconizing in Hopewell / USA Offset gravure coater Inerted ELTOSCH UV unit with 2 x160 W/cm UV lamps Web width 61 cm Substrate on 3 inch or 6 inch core Line speed m/min. Page 36

42 Market needs and conclusions Pilot Line for UV Siliconizing in Hopewell / USA come and see us for coating trials and discussions. Thank you for your attention Page 37

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