New waterbased UV curing PUD s for industrial wood finishing Laurie Morris Scientist Technical Service Alberdingk Boley, Inc.
Why use UV Curable Coatings? Benefits Little-no solvent emissions Excellent performance Smooth finish Rapid production Less floor space Extended open time during use (recyclable) Low cost per finished sq/ft Challenges High initial equipment costs Difficult to cure thick coatings Complex geometries can be difficult Some components are skin/eye irritant
Why Waterborne UV? Benefits Low viscosity w/o reactive diluents Zero VOC capable Low build appearance Water clean up High hardness & flexibility Little/no shrinkage - use of high MW resins Excellent adhesion Resoluble / reclaim overspray Easier equipment retrofit Gloss & viscosity control Challenges Some grain raising Drying ovens required Humidity dependence Finish defects (incomplete dry)
Radical Polymerization Ultraviolet (UV) curing is a photochemical process where intense UV light is used to cure coating Photopolymerization is achieved through a free radical mechanism A photoinitiator is the catalyst for the free radical mechanism UV light splits the photoinitiator into free radicals The radicals react with the double-bonds of the UVdispersion This produces more free radicals and the reaction process continues until terminated
Polymerization Reaction UV Light Photoinitiation IN R* initiator radicals Start R* + M R-M* radical resin intermediate Growth R-M* + M R-M-M* Termination R-M* + *M-R R-M-M-R
Alberdingk LUX 250 VP Solvent free aliphatic UV curable polyester polyurethane dispersion Excellent flexibility Very fast water release Excellent chemical and stain resistance Excellent scratch resistance Excellent boiling water resistance as measured by NEMA test 6
ALBERDINGK LUX 250 VP High blocking resistance Low wood grain raising Very good wood warmth Good wetting of pigments and matting agents Dual curing possible Easy to recycle 7
ALBERDINGK LUX 250 VP Physical Properties Solids (%) 39-41 ph 6.5 8.0 Viscosity (cps) 10-500 MFFT( o C) approx. 0 Koenig Hardness prior to UV cure (sec) 20 Koenig Hardness after UV cure (sec) 160 8
ALBERDINGK LUX 250 VP Applications include: - Clear and pigmented KCMA coatings - Clear and pigmented Furniture coatings - Cure on site parquet coatings - Clear plastic coatings (ABS, PC, PVC, PET) - General metal coatings 9
Starting Point Formulation Transparent, Matt Topcoat Raw Material Amount Type Supplier ALBERDINGK LUX 250 94.60 UV resin Alberdingk Boley, Inc. BYK 028 0.40 Defoamer BYK Chemie BYK 346 0.30 Surfactant BYK Chemie Ultralube D 816 1.50 Wax Keim Additec Acematt TS-100 2.00 Matting Agent Evonik Irgacure 500 1.00 Photoinitiator BASF DSX 1514 0.20 Rheology Modifier Cognis Curing Conditions: Pre-drying: 5 10 minutes @ 50 o C, convection dryer Feed: 15 20 feet/minute UV Curing: 1 Hg lamp, 80W/cm 10
Chemical Resistances: Test Chemicals Test Duration Test Results (0 5 5 = Best) Ethanol (48%) 1 hour 5 NH 4 OH (10%) 1 minute 5 Water 16 hours 5 Coffee (4%) 16 hours 5 Tea (1%) 16 hours 5 Red Wine 5 hours 5 Coke 16 hours 5 11
Starting Point Formulation White Topcoat Raw Material Amount Type Supplier ALBERDINGK LUX 250 61.2 UV resin Alberdingk Boley, Inc. Foamex 822 0.60 Defoamer Evonik BYK 094 0.20 Defoamer BYK Chemie BYK 346 0.30 Surfactant BYK Chemie Pigment paste 24.5 18% TiO2 Glycol Ether DPM 2.90 Solvent Water 7.80 Water Irgacure 500 1.00 Photoinitiator BASF Irgacure 819 DW 1.20 Photoinitiator BASF DSX 1514 0.30 Rheology Modifier Cognis Curing Conditions: Pre-drying: 5 10 minutes @ 50 o C, convection dryer Feed: 15 20 feet/minute UV Curing: 1 Ga-doped lamp, 120W/cm 1 Ga-doped + Hg-doped lamp, each 120 W/cm For additional crosslinking we suggest to add 10%of the following blend of polyisocyanates on total formulation weight: Bahydur XP 2487/1 in MPA (80/20). Pot life after addition = approximately 6 hours 12
Test Chemicals Test Duration Test Results UV cure only (0-5 5 = best) Test Results Dual Cure (0-5 5 = best) Ethanol 48% 1 hour 5 5 NH 4 OH (10%) 1 minute 5 5 Water 16 hours 5 5 Coffee (4%) 16 hours 4 5 Tea (1%) 16 hours 5 5 Red wine 5 hours 4 5 Coke 16 hours 5 5 13
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Chemical resistance (clear) 5 4 3 2 rating LUX 250 LUX 399 competitor 1 1 0 28 16 h Water 1 h Ethanol (48%) 5 h Ethanol (48%) 1 h NH3 (10%) 16 h Coffee test agent
Conclusion ALBERDINGK LUX 250 offers: - fast flash off - almost like ALBERDINGK LUX 399 - very high chemical resistance - superior mechanical resistances - excellent wood warming ( Anfeuerung ) - very easy matting without sedimentation - highly ph stable 29
Thank you for your attention!! want to know more?? visit us in booth 2841 30