Multifunctional UV/EB Curable Oligomers for Optical Coatings

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Reynold Mitchell
6 years ago
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1 Multifunctional UV/EB Curable Oligomers for Optical Coatings Jacobs Du, Aneta Bogdanova PCI Labs Innovative Coatings Through Research

2 UV/EB Curable Oligomers Introduction Need for novel UV/EB curable oligomers Multi-heterofunctional oligomers can fill a gap Oligomer synthesis and derivation Use of derived oligomers in anti-fog formulation

3 Curable Oligomers for Coating Design Advantages New polymers through varied curing Final polymer formed by the completion of curing process Same formulation may lead to different properties, depending on curing history/steps Molecular design through MW, backbone properties, cross linking density of formula to derive required adhesion, Tg, Tm, stress-strain, scratch resistance, chemical resistance, transparency and color, and shrinkage of coating

4 UV Curable Oligomers for Coating Process and Economics Fast cure (in seconds) means higher productivity Monomers and oligomers have lower viscosities that allow low VOC applications Allows usage on heat-sensitive substrates Dual cure (UV/EB light, heat, moisture)

5 UV/EB Curable Oligomer for Optical Coatings Optical clear coatings allow better UV penetration for complete cure Current oligomers did not meet requirements for multi-dimensional performance, thus heterofunctional oligomers are required Uses in anti-glare, anti-static, anti-microbial, antifog, anti-newton ring, self matting, soft touch, high and low refractive index coatings, among others

6 Derivation of Multi-heterofunctional Oligomers Usage of hyperbranched or dendrimeric material for obtaining multiheterofunctional oligomers. reactive groups, heterofunctional groups

7 Reaction Routes Under Study Route A: Conversion of dendrimeric reactive (acid) material to oligomers by reaction with heterofunctional reactants (epoxy-fg) Route B: Conversion of dendrimeric reactive (hydroxyl) material to oligomers by reaction with heterofunctional reactants (isocyanate-fg) Route C: In-depth conversion of commercialized oligomers Route D: Reaction of end-capped reactants with hyperbranched raw materials

8 Reaction Route A Reaction of acid groups on dendrimer with epoxy functional chains + Epoxy-FGA Epoxy-FGB Epoxy-FGC Heterofunctional groups

9 Reaction Route B Reaction of hydroxyl dendrimer with isocyanated functional chains + OCN-FGA OCN-FGB OCN-FGC Heterofunctional groups

10 Reaction Route C In-depth conversion of commercialized oligomers Bisphenol A Epoxy Acrylate + OCN-FGA OCN-PEO-FGB OCN-FGC Heterofunctional groups

11 Oligomers for the Study Oligomer Polyol Isocyanate End-cap App. Route A Route B O-A1 Polyester Dendrimer - Maleic acid GMA, Bisphenol A Epoxy Acrylate Epoxy-PEO-Acrylate O-B1 Branched PPO TDI DiPenta AF O-B2 Polyester Dendrimer, PEO IPDI, HMDI HEMA, Aliphaticacrylate O-B3 Polyester, PEO IPDI HEMA AF AF AF Route C O-C1 Polyester polyol Polymeric Isocyanates PETA O-C2 Polyester Dendrimer IPDI HEMA GA GA O-C3 Polybutadiene polyol IPDI DiPenta ST AF: anti-fog, GA: glass adhesion, ST: soft touch

Reaction Control and Monitoring 99.7 100.1 95 90 90 85 80 80 75 %T 70 %T 70 65 60 60 55 50 50 45 41.4 4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 650.0 cm-1 42.7 4000.

12 Reaction Control and Monitoring %T 70 %T cm cm-1 FTIR of a reaction mixture that includes polyester polyol, diisocyanates, and hydroxyfunctionalacrylates at two different stages. The peak at 2200 cm -1 on the left chart indicated unreacted isocyanate at an early stage of reaction, and the lack thereof on the right chart indicated the completion of urethane reaction

13 Reaction Control and Monitoring GPC of a reaction product that included polyester polyol, diisocyanates, hydroxyfunctionalacrylates. Multiple peaks reflects the presence of molecules of different molecular weight

14 Product Performance and Properties Excellent Abrasion, Chemical Resistance, and Scratch and Wear Resistance Variable Hardness-Elastomeric to Brittle Variable Gloss: 0 (High Diffusion) to 100 (Optical Clear) Better Stability Thermal, UV, and Environmental

15 Anti-Fog Application Anti-fog treatment prevents droplet formation of moisture by effectively spreading water molecules on a surface

16 Anti-Fog Application Traditional AF coating only has short term AF efficacy Regeneration of hydrophilic surface was sought to make long lasting AF surface Polyethylene glycol was implemented in oligomers as one of pro-hydrophilic segments Balanced hydrophilicity and hydrophobicity

17 Anti-Fog Samples and Tests Benchmark AF formulation was prepared using O-A1 and O-B3 oligomers Dip coating, flash off 3 min at 40 C, UV cure at 20 ft/min, mj/cm 2 Adhesion, hardness, abrasion and scratch resistance, fog resistance, fogging after freezing, cleaning ability, and chemical resistance were tested

18 Surface Tension Induced by Unbalanced Forces of Liquid Molecules on a AF Surface

19 Water Spread Rate as a Measure of Surface Tension

20 Fog Test of Samples Against Control Fog test at 25 C Beaker test at 60 C Coating ID Breath test Rainbow Fogging AF-1 PC No fog 0-5 sec No fog > 30 min Uncoated PC Fog immediately Fog immediately

21 Fog Test after Freezing Test 1 Place sample at -15 C for 45 minutes, observe for fogging at RT for 90 sec or longer. Freeze for another 15 min. Beaker test (60 C) immediately for 90 sec or longer by placing the sample over beaker AF-1-PC Fog Start Fog End Non-uniform Uniform Film RT No fog Beaker No fog n/a n/a Test 2 Contact angle was 7 under freezing for day 1, 15 and 30, indicating long term AF stability on freezing

22 Cleaning Durability Test of AF Coating Coating ID Before Test Cycle 1-11 AF-1 PC No fog 1-30 sec. No fog 1-30 sec. Samples were sprayed with Windex then wiped clean with a dry scratch free rag. Anti-fog properties were tested by doing the beaker test at 60 C after each cycle.

23 Adhesion and Scratch Resistance ASTM 3359 Peel Adhesion Test: 100% Adhesion after boiling: 100% Scratch Resistance: Rotary Steel wool test (0000 steel wool grade): 2 psi

24 Abrasion Resistance (Taber) AF-1-PC after 100 cycles after 500 cycles Haze gain (%) 9.7% 31.5% *ASTM D CS10F, 500g load

25 High Temperature Resistance Before Treatment After Treatment Gain YI E (%) % Haze (%) % Luminous transmission (%) % Adhesion (%) Pass Pass No change Anti-fog No fog No fog No change *100 C, 24 hrs

26 Chemical Resistance of AF Coating Uncoated Coated Distilled White Vinegar 2 minutes 10 minutes Acetone 2 minutes 2 minutes Ethanol < 30 minutes < 30 minutes 28% Ammonia Hydroxide 2 minutes 8 minutes 10% Sodium Hydroxide < 30 minutes 4 minutes 10% Sulfuric Acid < 30 minutes 18 minutes Butyl Acetate 2 minutes 4 minutes MEK 4 minutes 2 minutes MIBK 4 minutes 8 minutes MIAK 2 minutes 2 minutes

27 Comparison of AF-1-PC against a Sample from Commercial Source AF-1 - PC Commercial sample Haze Yellow Index Transmittance % Adhesion, % Thickness, mil Scratch Resistance, psi 2 to 3 1 to 2 Pencil Hardness HB B Breathing Test Anti-fog Anti-fog Boiling Test, % adh. 100 failed Fogging test, min w/o fogging

28 Applications of Oligomers Dual Cure Anti-fog Coatings with Glass Adhesion, e.g. combination of O-C1 and O-C2 Soft -touch Coatings, e.g. O-C3 Hard Coating Inks

29 Conclusion UV/EB curable hetero-functional oligomers have been developed based on highly branched and dendrimeric raw materials. Raw materials with different hydrophilicity, elasticity, and formulation compatibility were investigated. Application for anti-fog, glass adhesion, and soft touch have been investigated. Anti-fog samples with prolonged anti-fog performance was observed under normal conditions. Robust anti-fog performance under freezing and high temperature exposure was achieved. AF samples effectively improved anti-fog performances versus commercial alternatives obtained.

UV/EB Thermoset Polymers Intended for. Thermoforming Applications

UV/EB Thermoset Polymers Intended for Introduction Thermoforming Applications Robert Kensicki The process of thermoforming is not a new concept as it has been used for many years with the process being