Reactive mixture for coating molded objects by means of reaction injection molding and coated molded object

Patent metadata

Field	Value
Publication number	US-9410043-B2
Application number	US-201213546051-A
Country	US
Kind code	B2
Filing date	Jul 11, 2012
Priority date	Jun 19, 2007
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A reactive mixture for coating mouldings by means of reaction injection moulding, containing at least 40% by weight of (meth)acrylates having at least two double bonds. The reactive mixture contains at least one photoinitiator and at least one thermal initiator. The present invention furthermore describes a coated moulding including a moulding which is obtainable by injection moulding processes and includes at least one polymer selected from polymethyl methacrylate, polymethylmethacrylimide, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer and polymethyl methacrylate copolymers, and a coating which is obtainable by polymerization of (meth)acrylates having at least two double bonds. The coating has an adhesive strength rating of not more than 1 according to the cross hatch test and a decrease in gloss at 20° after a scratch resistance test according to ASTM 1044 (12/05) (applied weight 500 g, number of cycles=100) of not more than 10%.

First claim

The invention claimed is:

1. A process for the production of coated mouldings, the process comprising injecting a moulding material into an injection mould and cooling to produce a moulding, wherein the injection mould is changed so that a space forms between a surface of the moulding which is to be coated and an inner surface of the injection mould, the resulting space is filled by injection moulding with a reactive mixture comprising at least 40% by weight of (meth)acrylates having at least two double bonds, at least one photoinitiator and at least one thermal initiator, and the reactive mixture is first thermally cured and, after the thermal curing, cured by irradiation.

2. The process according to claim 1 , wherein the moulding material comprises at least one polymer selected from the group consisting of polymethyl methacrylate, polymethylmethacrylimide, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer and polymethyl methacrylate copolymers.

3. The process according to claim 2 , wherein the moulding material comprises at least 50% by weight of polymethyl methacrylate, polymethyl methacrylimide and/or polymethyl methacrylate copolymers.

4. The process according to claim 1 , wherein the thickness of the coating is in the range of 5 μm to 75 μm.

5. The process according to claim 1 , wherein the moulding material is injected into the injection mould at a temperature in the range of 220 to 330° C.

6. The process according to claim 1 , wherein the moulding material is cooled to a temperature in the range of 70 to 150° C. before the reactive mixture is injected into the space.

7. The process according to claim 1 , wherein the reactive mixture is thermally cured at a temperature in the range of 80 to 130° C. in the injection mould.

8. The process according to claim 1 , wherein the thermally cured reactive mixture is cured by irradiation at a temperature in the range of 10 to 40° C.

9. The process according to claim 8 , wherein the thermally cured reactive mixture is cured using UV radiation.

10. The process according to claim 1 , wherein the reactive mixture comprises at least 60% by weight of (meth)acrylates having at least two double bonds.

11. The process according to claim 1 , wherein the reactive mixture comprises at least one (meth)acrylate having three or more double bonds.

12. The process according to claim 11 , wherein the proportion of (meth)acrylates having three or more double bonds is at least 25% by weight, based on the weight of the reactive mixture.

13. The process according to claim 12 , wherein the proportion of (meth)acrylates having three or more double bonds is at least 50% by weight, based on the weight of the reactive mixture.

14. The process according to claim 1 , wherein the reactive mixture comprises not more than 75% by weight of monomers having two or less double bonds.

15. The process according to claim 1 , wherein the reactive mixture has a dynamic viscosity in the range of 1 to 200 mPa·s at 25° C.

16. The process according to claim 1 , wherein the reactive mixture comprises 0.01% by weight to 3% by weight of photoinitiator, based on the weight of the reactive mixture.

17. The process according to claim 1 , wherein the reactive mixture comprises 0.03% by weight to 5% by weight of thermal initiator, based on the weight of the reactive mixture.

18. The process according to claim 1 , wherein the weight ratio of photo initiator to thermal initiator is in the range of 20:1 to 1:5.

19. The process according to claim 1 , wherein the reactive mixture comprises 1,6-hexanediol diacrylate, trimethylolpropane triacrylate and/or pentaerythrityl tetraacrylate.

20. The process according to claim 19 , wherein the reactive mixture comprises trimethylolpropane triacrylate and 1,6-hexanediol diacrylate, the weight ratio of trimethylolpropane triacrylate to 1,6-hexanediol diacrylate being in the range of 5:1 to 1:5.

21. The process according to claim 19 , wherein the reactive mixture comprises trimethylolpropane triacrylate and pentaerythrityl tetraacrylate, the weight ratio of trimethylolpropane triacrylate to pentaerythrityl tetraacrylate being in the range of 5:1 to 1:5.

22. The process according to claim 19 , wherein the reactive mixture comprises pentaerythrityl tetraacrylate and 1,6-hexanediol diacrylate, the weight ratio of pentaerythrityl tetraacrylate to 1,6-hexanediol diacrylate being in the range of 5:1 to 1:5.

23. The process according to claim 1 , wherein the reactive mixture comprises a lubricant.

24. The process according to claim 1 , wherein the reactive mixture comprises colorants, metallic pigments, UV stabilizers, fillers or nanomaterials.

25. The process according to claim 1 , wherein the reactive mixture comprises at least 90% by weight of (meth)acrylates having at least two double bonds.

Assignees

• Schultes Klaus
• Goldacker Thorsten
• Koralewski Klaus
• Höβ Werner
• Seyoum Ghirmay
• Gross Elevtherios
• Felger Erwin
• Evonik Roehm Gmbh

Inventors

• Schultes Klaus
• Goldacker Thorsten
• Koralewski Klaus
• Höβ Werner
• Seyoum Ghirmay
• Gross Elevtherios
• Felger Erwin

Classifications

• Y10T428/31721

  Of polyimide · CPC title

• B29C45/0001

  characterised by the choice of material · CPC title

• C09D4/00 Primary

  Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond {; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16} · CPC title

• Y10T428/31928

  Ester, halide or nitrile of addition polymer · CPC title

• B29C45/1679

  applying surface layers onto injection-moulded substrates inside the mould cavity, e.g. in-mould coating [IMC] (applying suface layers after ejection B29C45/0053) · CPC title