High pressure laminate panel and method for the production thereof

Abstract

The invention relates to a high pressure laminate panel having a surface layer on at least one panel surface, which has as the outermost layer a polymer coating with a polyurethane(meth)acrylate polymer, and which is characterized by excellent scratch resistance and resistance to weathering. Furthermore, a method for the production of polyurethane(meth)acrylate-coated high pressure laminate panels is provided.

Claims

1. Method for the production of a high pressure laminate panel having a core layer and a polymer-coated surface layer on at least one panel surface, wherein the surface layer has as the outermost layer a polymer coating with a polyurethane(meth)acrylate polymer and wherein the method comprises the following steps: a) applying a coating system as a coating on a surface material for a high pressure laminate panel, wherein the coating system comprises a resin component, a hardener component, and optional additives, wherein the resin component is present as a mixture of components A to D, in which component A is a polymerizable (meth)acrylate compound having at least 2 groups with a (meth)acrylic double bond and no hydroxy groups per molecule, component B is a polymerizable (meth)acrylate compound having both one or more groups with a (meth)acrylic double bond as well as at least 2 hydroxy groups per molecule, component C is a polyurethane prepolymer having at least 2 hydroxy groups and no isocyanate groups per molecule, component D is a resin with an aminoplast structure having at least 2 hydroxy groups per molecule; and wherein the hardener component is an at least difunctional isocyanate; and b) drying the surface material coated in step a) at an elevated temperature at which a reaction takes place between the hydroxy groups in the resin component and the isocyanate groups of the hardener component so that a polyurethane polymer is formed in the coating which comprises groups with a (meth)acrylic double bond; c) providing a laminate stack comprising a material for the formation of a core layer of a high pressure laminate panel, said material comprising one or more layers of a carrier material impregnated with a curable synthetic resin, and comprising the coated surface material obtained in step b) as a surface layer so that at least on one side of the laminate stack the surface material obtained in step b) forms the outermost layer, and the dried coating is present on at least one surface of the laminate stack; d) pressing the laminate stack at increased pressure and at a temperature above the drying temperature of step b) so that a polymerization of the (meth)acrylic double bonds in the dried coating takes place and a high pressure laminate panel with a core layer and a surface layer on at least one panel surface is formed which as the outermost layer has a polymer coating with a polyurethane(meth)acrylate polymer.

2. Method according to claim 1, wherein the compound of component A does not comprise any other reactive groups in addition to the groups with a (meth)acrylic double bond.

3. Method according to claim 1, wherein the (meth)acrylate compound of component A comprises a compound of the following formula (A1):
[H.sub.2CCHC(O)O-].sub.mR.sup.1OC(O)NHR.sup.2NHC(O)OR.sup.3[OC(O)CHCH.sub.2].sub.n(A1); wherein R.sup.1 and R.sup.3 are independently selected from an aliphatic hydrocarbon group, an aliphatic polyether group, and an aliphatic polyester group, R.sup.2 is an aliphatic or cycloaliphatic hydrocarbon group, n=2-9, and m=2-9.

4. Method according to claim 1 wherein the (meth)acrylate compound of component A comprises a compound of the following formula (A2):
[H.sub.2CCHC(O)O-].sub.oR.sup.4(A2) wherein R.sup.4 is an aliphatic hydrocarbon group, and o=2-6.

5. Method according to claim 1, wherein the (meth)acrylate compound of component B comprises a compound of the following formula (B1):
[H.sub.2CCHC(O)O-].sub.pR.sup.5OC(O)NHR.sup.6NHC(O)OR.sup.7(OH).sub.2(B1) wherein R.sup.5 is selected from an aliphatic hydrocarbon group, an aliphatic polyether group, and an aliphatic polyester group, R.sup.6 and R.sup.7 are independently an aliphatic or cycloaliphatic hydrocarbon group, and p=2-9.

6. Method according to claim 1, wherein the polyurethane prepolymer of component C does not comprise any other reactive groups in addition to the hydroxy groups.

7. Method according to claim 1, wherein the polyurethane prepolymer of component C comprises a compound of the formula (C1) and/or (C2): ##STR00013## wherein R.sup.8, independently at every occurrence, is selected from an aliphatic hydrocarbon group which can be substituted with one or more hydroxyl groups, an aliphatic polyether group, and an aliphatic polyester group, R.sup.9, independently at every occurrence, is selected from an aliphatic or cycloaliphatic hydrocarbon group, and q is 2-9; ##STR00014## wherein R.sup.8 and R.sup.8a, independently at every occurrence, are selected from an aliphatic hydrocarbon group, which can be substituted with one or more OH groups, an aliphatic polyether group, and an aliphatic polyester group, R.sup.9, independently at every occurrence, is an aliphatic or cycloaliphatic hydrocarbon group, and q is 2-9.

8. Method according to claim 1, wherein the resin with an aminoplast structure of component D is a resin with a urea-formaldehyde resin structure.

9. Method according to claim 1, wherein in the resin component, component A is present in an amount of 40.0 to 80.0 wt. %, component B is present in an amount of 19.0 to 55.0 wt. %, component C is present in an amount of 0.5 to 5 wt. %, and component D is present in an amount of 0.5 to 7 wt. %, based on the total weight of the resin component as 100 wt. %.

10. Method according to claim 1, wherein drying is carried out at a temperature of 130 C. or less.

11. Method according to claim 1, wherein the temperature for the polymerization of the (meth)acrylic double bonds is above 130 C.

12. Method according to claim 1, wherein step d) is carried out in a hot press equipped with a structuring surface which imparts a surface structure to the high pressure laminate panel.

13. Method for the production of a polymer-coated surface material for a high pressure laminate panel comprising the steps: applying a coating system as a coating on a surface material for a high pressure laminate panel, wherein the coating system comprises a resin component, a hardener component, and optional additives, wherein the resin component is present as a mixture of components A to D, in which component A is a polymerizable (meth)acrylate compound having at least 2 groups with a (meth)acrylic double bond and no hydroxy groups per molecule, component B is a polymerizable (meth)acrylate compound having one or more groups with a (meth)acrylic double bond as well as at least 2 hydroxy groups per molecule, component C is a polyurethane prepolymer having at least 2 hydroxy groups and no isocyanate groups per molecule, component D is a resin with an aminoplast structure having at least 2 hydroxy groups per molecule; and wherein the hardener component is an at least difunctional isocyanate; and drying the surface material coated in step a) at an elevated temperature at which a reaction takes place between the hydroxy groups in the resin component and the isocyanate groups of the hardener component so that a polyurethane polymer is formed in the coating which comprises groups with a (meth)acrylic double bond, and, in addition, after drying optionally polymerizing the (meth)acrylic double bonds in the dried coating at a temperature above the drying temperature so that a polyurethane(meth)acrylate polymer is formed in the coating.

Description

EXAMPLES

Example 1

(1) For preparing a coating system, 100 parts by weight of a mixture of the following components in n-butyl acetate and a total solids content of 70%: 32 parts by weight
[H.sub.2CCHC(O)O-].sub.mR.sup.1OC(O)NHR.sup.2NHC(O)OR.sup.3[OC(O)CHCH.sub.2].sub.n(A1) wherein R.sup.1(CH.sub.2).sub.3CCH.sub.2 R.sup.2=3,3,5,5-tetramethylcyclohexanediyl R.sup.3CH.sub.2C(CH.sub.2-).sub.3 and n=3 and m=3;

(2) 32.6 parts by weight
[H.sub.2CCHC(O)O-].sub.oR.sup.4(A2) wherein R.sup.4C(CH.sub.2-).sub.4 and o=4;

(3) 30.1 parts by weight
[H.sub.2CCHC(O)O-].sub.pR.sup.5OC(O)NHR.sup.6NHC(O)OR.sup.7(OH).sub.2(B1) wherein R.sup.5(CH.sub.2).sub.3CCH.sub.2 R.sup.6=3,3,5,5-tetramethylcyclohexanediyl R.sup.7CH.sub.2C(CH.sub.2).sub.2CH.sub.3 and p=3;

(4) 1.9 parts by weight

(5) ##STR00005## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.9=3,3,5,5-tetramethylcyclohexanediyl and q=3; and

(6) ##STR00006## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.8aCH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2)(CH.sub.2) R.sup.9=3,3,5,5-tetramethylcyclohexanediyl and q=3; and

(7) 3.4 parts by weight

(8) D: cured urea-formaldehyde resin with a molecular weight Mn of >1,000 g/mol]

(9) are mixed in a reaction vessel with 28 parts by weight of a hardener component in the form of a trimerized hexamethylene diisocyanate with an isocyanate equivalent weight of 195, and 0.1 parts by weight of tert. butyl perbenzoate were added as radical former. The half-life period of tert. butyl perbenzoate at 140 C. is about 10 minutes. Common additives for coating systems can also be added to this coating system, such as flow agents, anti-foaming agents, light stabilizers, and degassing agents. The pot life of the coating system is 1-1.5 hours.

(10) The coating system is applied in a coating machine to a paper web impregnated with curable resins as the surface material for a high pressure laminate panel by means of application rollers. The coating system is applied at a thickness of 80+/3 g/m.sup.2. Subsequently, a partial crosslinking reaction takes place between the isocyanate group of the hardener component and the free hydroxyl groups of the resin component in the dryer of a coating machine at a temperature of 125 C. so that a resin component with (meth)acrylic double bonds is formed. The throughput rate in the dryer is selected such that the coated carrier material is present as a dry-to-handle film which can be stored for an unlimited period of time.

(11) For the production of high pressure laminate panels with a polyurethane acrylate surface, the coated surface material is stacked as follows with the other components of the laminate stack: coated surface material (decorated layer)/core layer consisting of about 12 paper webs impregnated with phenolic resin/coated surface material (decorated layer). The polymer coating of the surface material is present as the outermost layer on both sides of the laminate stack.

(12) This laminate stack is pressed for 20 minutes with a pressure of 80 bar and at a temperature of 140 C. At these reaction temperatures, the additional crosslinking reaction of the reactive (meth)acrylic double bonds takes place due to the radical formers present in the coating system, and a cured polyurethane acrylate is formed. At the same time, the impregnating resins used in the decorative and core layers are cured. After 20 minutes, the laminate stack is cooled under pressure and removed from the press. The surface properties of the thus obtained high pressure laminate panel are shown in the table below.

Example 2

(13) For preparing a coating system, 100 parts by weight of a mixture of the following components in n-butyl acetate and a total solids content of 76%:

(14) 26 parts by weight
[H.sub.2CCHC(O)O-].sub.mR.sup.1OC(O)NHR.sup.2NHC(O)OR.sup.3[OC(O)CHCH.sub.2].sub.n(A1) wherein R.sup.1(CH.sub.2).sub.3CCH.sub.2 R.sup.2=3,3,5,5-tetramethylcyclohexanediyl R.sup.3CH.sub.2C(CH.sub.2).sub.2CH.sub.2CH.sub.3 and n=2 and m=3;

(15) 30.5 parts by weight
[H.sub.2CCHC(O)O-].sub.oR.sup.4(A2) wherein R.sup.4C(CH.sub.2-).sub.4 and o=4;

(16) 40.5 parts by weight
[H.sub.2CCHC(O)O-].sub.pR.sup.5OC(O)NHR.sup.6NHC(O)OR.sup.7(OH).sub.2(B1) wherein R.sup.5(CH.sub.2).sub.3CCH.sub.2 R.sup.6=3,3,5,5-tetramethylcyclohexanediyl R.sup.7CH.sub.2C(CH.sub.2).sub.2CH.sub.3 and p=3;

(17) 1.5 parts by weight

(18) ##STR00007## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.9=3,3,5,5-tetramethylcyclohexanediyl and q=3; and

(19) ##STR00008## wherein R.sup.5=CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.8aCH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2)(CH.sub.2) R.sup.9=3,3,5,5-tetramethylcyclohexanediyl and q=3; and

(20) 1.5 parts by weight

(21) D: cured urea-formaldehyde resin with a molecular weight Mn of >1,000 g/mol]

(22) are mixed in a reaction vessel with 28 parts by weight of a hardener component in the form of a trimerized hexamethylene diisocyanate with an isocyanate equivalent weight of 195, and 0.1 parts by weight of tert. butyl perbenzoate were added as radical former. The half-life period of tert. butyl perbenzoate at 140 C. is about 10 minutes. Common additives for coating systems can also be added to this coating system, such as flow agents, anti-foaming agents, light stabilizers, and degassing agents. The pot life of the coating system is 1-1.5 hours.

(23) Subsequently, the coating system is applied to a surface material as described in Example 1, and a high pressure laminate panel is produced. The surface properties of the thus obtained high pressure laminate panel are shown in the table below.

Example 3

(24) For preparing a coating system, 100 parts by weight of a mixture of the following components in n-butyl acetate and a total solids content of 82%:

(25) 35 parts by weight
[H.sub.2CCHC(O)O-].sub.mR.sup.1OC(O)NHR.sup.2NHC(O)OR.sup.3[OC(O)CHCH.sub.2].sub.n(A1); wherein R.sup.1(CH.sub.2).sub.3CCH.sub.2 R2CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 R.sup.3CH.sub.2C(CH.sub.2-).sub.3 and n=3 and m=3;

(26) 25.8 parts by weight
[H.sub.2CCHC(O)O-].sub.oR.sup.4(A2) wherein R.sup.4C(CH.sub.2-).sub.4 and o=4;

(27) 34 parts by weight
[H.sub.2CCHC(O)O-].sub.pR.sup.5OC(O)NHR.sup.6NHC(O)OR.sup.7(OH).sub.2(B1) wherein R.sup.5(CH.sub.2).sub.3CCH.sub.2 R.sup.6=CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 R.sup.7CH.sub.2C(CH.sub.2).sub.2CH.sub.3 and p=3;

(28) 0.8 parts by weight

(29) ##STR00009## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.9=CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 and q=3, and

(30) ##STR00010## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.9=CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 R.sup.8aCH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2)(CH.sub.2) and q=3;

(31) 4.4 parts by weight

(32) D: cured urea-formaldehyde resin with a molecular weight Mn of >1,000 g/mol]

(33) are mixed in a reaction vessel with 28 parts by weight of a hardener component in the form of a trimerized hexamethylene diisocyanate with an isocyanate equivalent weight of 195, and 0.1 parts by weight of tert. butyl perbenzoate were added as radical former. The half-life period of tert. butyl perbenzoate at 140 C. is about 10 minutes. Common additives for coating systems can also be added to this coating system, such as flow agents, anti-foaming agents, light stabilizers, and degassing agents. The pot life of the coating system is 1-1.5 hours.

(34) Subsequently, the coating system is applied to a surface material as described in Example 1, and a high pressure laminate panel is produced. The surface properties of the thus obtained high pressure laminate panel are shown in the table below.

Example 4

(35) For preparing a coating system, 100 parts by weight of a mixture of the following components in n-butyl acetate and a total solids content of 75%:

(36) 29.4 parts by weight
[H.sub.2CCHC(O)O-].sub.mR.sup.1OC(O)NHR.sup.2NHC(O)OR.sup.3[OC(O)CHCH.sub.2].sub.n(A1); wherein R.sup.1(CH.sub.2).sub.3CCH.sub.2 R2CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 R.sup.3CH.sub.2C(CH.sub.2).sub.2CH.sub.2CH.sub.3 and n=2 and m=3;

(37) 31.5 parts by weight
[H.sub.2CCHC(O)O-].sub.oR.sup.4(A2) wherein R.sup.4C(CH.sub.2-).sub.4 and o=4;

(38) 33 parts by weight
[H.sub.2CCHC(O)O].sub.pR.sup.5OC(O)NHR.sup.6NHC(O)OR.sup.7(OH).sub.2(B1) wherein R5=(CH.sub.2).sub.3CCH.sub.2 R.sup.6=CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 R.sup.7CH.sub.2C(CH.sub.2).sub.2CH.sub.3 and p=3;

(39) 2.0 parts by weight

(40) ##STR00011## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.9=CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 and q=3; and

(41) ##STR00012## wherein R.sup.8CH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2OH)(CH.sub.2) R.sup.9=CH.sub.2C(CH.sub.3)(CH.sub.3)CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2 R.sup.8aCH.sub.2C(CH.sub.2CH.sub.3)(CH.sub.2)(CH.sub.2) and q=3;

(42) 4.1 parts by weight

(43) D: cured urea-formaldehyde resin with a molecular weight Mn of >1,000 g/mol]

(44) are mixed in a reaction vessel with 28 parts by weight of a hardener component in the form of a trimerized hexamethylene diisocyanate with an isocyanate equivalent weight of 195, and 0.1 parts by weight of tert. butyl perbenzoate were added as radical former. The half-life period of tert. butyl perbenzoate at 140 C. is about 10 minutes. Common additives for coating systems can also be added to this coating system, such as flow agents, anti-foaming agents, light stabilizers, and degassing agents. The pot life of the coating system is 1-1.5 hours.

(45) Subsequently, the coating system is applied to a surface material as described in Example 1, and a high pressure laminate panel is produced. The surface properties of the thus obtained high pressure laminate panel are shown in the table below.

(46) TABLE-US-00001 Example 1 Example 2 Example 3 Example 4 Weathering after 3,500 h: after 3,500 h: after 3,500 h: after 3,500 h: according to grey scale 5 grey scale 4 grey scale 4 grey scale 4-5 EN 438-2.29: 2005 appearance 5 appearance 5 appearance 5 appearance 5 Scratch resistance 7N 6N 6N 7N according to EN 438-2.25: 2005 Change in degree of 2.0 units or 1.6 units or 2.5 units or 2.1 units or gloss at 85 after 15% of the 11% of the 18% of the 16% of the weathering starting value starting value starting value starting value according to EN 438-2.29: 2005 measured after 3,500 h according to EN ISO 2813 Chemical resistance Level 5 Level 5 Level 5 Level 5 according to EN 438-2.26: 2005 Nitrogen content 11% 5% 14% 13% from NCON groups based on the total N content according to EN ISO 10993-18: 2009