UV curable coating composition
View Patent ↗The invention provides an isocyanate free UV curable hot melt composition which may be hardened upon exposure to UV radiation to provide a protective coating. The coating is particularly useful in wood-working and furniture applications.
1. An isocyanate free, radiation curable hot melt coating composition comprising a solvent-free radiation curable polymer component; an oligomer component; a photoinitiator and optionally a monomer component, wherein
the polymer component comprises poly(meth)acrylate segments and polyurethane segments, has a Mn>2000 g per mole and has at least one functional group polymerisable under UV radiation,
the oligomeric component has Mn from 500 to 5000 g per mole and contains at least two functional groups polymerisable under UV radiation,
the monomer component has Mn from 100 to 1000 g per mole and contains at least one functional group polymerisable under UV radiation, and
the coating composition is solid at room temperature and has a melt viscosity greater than about 3700 cP at the coating composition application temperature.
2. The isocyanate free coating composition of claim 1 further comprising the monomer component.
3. The isocyanate free coating composition of claim 1 comprising a solvent-free radiation curable hot melt composition comprising the polymer component, the oligomer component, the monomer component and the photoinitiator.
4. The isocyanate free coating composition of claim 1 where the polymer component has a Mn of from 5,000 to 100,000 g per mole.
5. An isocyanate free coating composition comprising a solvent-free radiation curable hot melt composition consisting essentially of 60%-95% of a polymer component, 5-40% of an oligomeric component and 0.1-10% of a photoinitiator, wherein
the polymer component comprises poly(meth)acrylate segments and polyurethane segments, has a Mn>2000 g per mole and has at least one functional group polymerisable under UV radiation and
the oligomeric component has Mn from 500 to 5000 g per mole and contains at least two functional groups polymerisable under UV radiation.
6. The isocyanate free coating composition of claim 1 comprising 30%-90% of the polymer component, 5-40% of the oligomeric component, 5-40% of the monomer component and 0.1-10% of the photoinitiator.
7. The isocyanate free coating composition of claim 1 wherein the polymer component is the reaction product of poly(meth)acrylate polymer containing acid or hydroxyl functional groups.
8. The isocyanate free coating composition of claim 1 further comprising a filler.
9. The isocyanate free coating composition of claim 1 where the melt viscosity is below 20,000 cP at the coating composition application temperature.
10. A method of coating a substrate comprising:
providing the coating composition of claim 1 at room temperature in solid form;
melting the coating composition; and
applying the melted coating composition of claim 1 to a substrate, wherein the temperature of said isocyanate free coating composition is below 120° C. at the time of application to said substrate.
11. The method of claim 10 wherein the temperature of the isocyanate free coating composition is from about 70 to about 110° C. at the time of application to said substrate.
12. A substrate comprising a layer of the solvent-free radiation curable composition of claim 1 .
13. The substrate of claim 12 further comprising a layer of a radiation curable lacquer.
14. A coated substrate comprising a layer of the solvent-free radiation curable composition of claim 1 which has been cured by exposure to UV radiation.
15. An article of manufacture, at least a portion of which comprises the coated substrate of claim 14 .
16. The method of claim 10 further comprising allowing the melted coating composition to cool and solidify and exposing the coating composition to radiation to cure the coating composition.
17. A hot melt, isocyanate free, solvent-free coating composition comprising a solvent-free, radiation curable polymer component, an oligomeric component, a monomer component, and a photoinitiator, wherein
the polymer component comprises poly(meth)acrylate segments and polyurethane segments, has a Mn>2000 g per mole and has at least one functional group polymerisable under UV radiation,
the oligomeric component has Mn from 500 to 5000 g per mole and contains at least two functional groups polymerisable under UV radiation,
the monomer component has Mn from 100 to 1000 g per mole and contains at least one functional group polymerisable under UV radiation, and
the coating composition has a melting point of about 70° C. to about 110° C. and the melt viscosity of the coating composition is greater than about 3700 cP at the coating composition application temperature.
18. The hot melt, isocyanate free, solvent-free coating composition of claim 17 wherein the radiation curable polymer component does not contain allophanate groups.