New waterbased UV curing PUD‘s for industrial wood finishing

Laurie MorrisScientist – Technical ServiceAlberdingk Boley, Inc.

Why use UV Curable Coatings?

Benefits• Little-no solvent emissions• Excellent performance• Smooth finish

Challenges• High initial equipment

costs• Difficult to cure thick • Smooth finish

• Rapid production• Less floor space • Extended open time

during use (recyclable)• Low cost per finished sq/ft

• 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

Challenges• Some grain raising• Drying ovens required• Humidity dependence• Finish defects (incomplete dry)• 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

• 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 • 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 UV-

dispersion• This produces more free radicals and the reaction

process continues until terminated

Polymerization Reaction

Photoinitiation IN R* initiator radicals

Start R* + M R-M*

UV Light

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• Very fast water release• Excellent chemical and

stain resistance• Excellent scratch

resistance• Excellent boiling water

resistance as measured by NEMA test

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ALBERDINGK® LUX 250 VP

• High blocking resistance• Low wood grain raising• Very good wood warmth• Very good wood warmth• Good wetting of pigments

and matting agents• Dual curing possible• Easy to recycle

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ALBERDINGK® LUX 250 VP

Physical Properties

Solids (%) 39 - 41pH 6.5 – 8.0

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pH 6.5 – 8.0Viscosity (cps) 10 - 500MFFT(oC) approx. 0Koenig Hardness prior to UV cure (sec) 20Koenig Hardness after UV cure (sec) 160

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

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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

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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 @ 50o C, convection dryer Feed: 15 – 20 feet/minute UV Curing: 1 Hg lamp, 80W/cm

Chemical Resistances:

Test Chemicals Test Duration Test Results

(0 – 5 5 = Best) Ethanol (48%) 1 hour 5

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Ethanol (48%) 1 hour 5

NH4OH (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

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

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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 @ 50o 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

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

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Ethanol 48% 1 hour 5 5

NH4OH (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

Flash off time

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Flash off time

15

Flash off time

16

Flash off time

17

Flash off time

18

Flash off time

19

Flash off time

20

Flash off time

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Flash off time

22

Flash off time

23

Flash off time

24

Flash off time

25

Flash off time

26

Flash off time

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Chemical resistance (clear)

3

4

5

ratin

gLUX 250LUX 399

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0

1

2

ratin

g

1 h Etha

nol (4

8%)

5 h Etha

nol (4

8%)

1 h N

H3 (10

%)

16 h

Coffee

16 h

Water

test agent

LUX 399competitor 1

Conclusion

• ALBERDINGK® LUX 250 offers:- fast flash off - almost like ALBERDINGK® LUX 399- very high chemical resistance- superior mechanical resistances

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- superior mechanical resistances- excellent wood warming ( Anfeuerung )- very easy matting without sedimentation- highly pH stable

Thank you for your attention !!

want to know more ??

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want to know more ??visit us in booth 2841