Laminate

Abstract

The present invention provides a laminate excellent in abrasion resistance, high in hardness, and excellent in adhesion between a substrate and a primer layer and adhesion between an intermediate layer and a top coat layer. The laminate includes: a substrate; a primer layer disposed on the substrate, the primer layer containing inorganic particles (a1) having an average particle size of 3 μm or greater and a heat-resistant resin (a2), but not containing a fluororesin; an intermediate layer disposed on the primer layer and containing a fluororesin (b1) and a heat-resistant resin (b2); and a top coat layer disposed on the intermediate layer and containing a fluororesin (c1).

Claims

1. A laminate comprising: a substrate; a primer layer disposed on the substrate, the primer layer containing inorganic particles (a1) having an average particle size of 3 μm or greater and a heat-resistant resin (a2), but not containing a fluororesin; an intermediate layer disposed on the primer layer and containing a fluororesin (b1) and a heat-resistant resin (b2); and a top coat layer disposed on the intermediate layer and containing a fluororesin (c1), wherein the top coat layer contains inorganic particles (c2), wherein the inorganic particles (c2) have an average particle size of 14 μm or greater, wherein the inorganic particles (a1) and (c2) have a Knoop hardness of 1200 or higher, and are zirconia, aluminum nitride, beryllia, zirconium nitride, zirconium boride, titanium nitride, tantalum carbide, tungsten carbide, aluminum oxide, zirconium carbide, titanium carbide, silicon carbide, aluminum boride, or titanium boride, wherein the top coat layer has a thickness of 10 to 40 μm, wherein the amount of the heat-resistant resin (b2) is 10 to 40 mass % based on the whole mass of the intermediate layer, and wherein the intermediate layer is free from inorganic particles (a1) and the inorganic particles (c2).

2. The laminate according to claim 1, wherein the heat-resistant resin (a2) is at least one selected from the group consisting of polyamide-imides, polyimides, and polyethersulfones.

3. The laminate according to claim 1, wherein the fluororesin (c1) contains polytetrafluoroethylene.

4. The laminate according to claim 1, wherein the primer layer is obtained by applying a water paint containing the inorganic particles (a1) and the heat-resistant resin (a2) to the substrate.

5. The laminate according to claim 1, wherein the primer layer has a thickness of 10 to 30 μm.

6. The laminate according to claim 1, wherein the intermediate layer is free from inorganic particles.

7. The laminate according to claim 1, wherein the fluororesin (b1) contains polytetrafluoroethylene.

8. The laminate according to claim 1, wherein the heat-resistant resin (b2) is at least one selected from the group consisting of polyamide-imides, polyimides, and polyethersulfones.

9. The laminate according to claim 1, wherein the primer layer has a maximum height roughness (Rz) of 10 μm or higher.

Description

EXAMPLES

(1) The present invention will be specifically described below referring to, but not limited to, examples and comparative examples. The terms “%” and “part(s)” respectively mean mass % and part(s) by mass.

Production Example 1: Preparation of Polyethersulfone Resin Aqueous Dispersion

(2) First, 60 parts of polyethersulfone resin (PES) having a number average molecular weight of about 24000 and 60 parts of deionized water were stirred in a ceramic ball mill until the PES particles were completely pulverized. Next, 180 parts of N-methyl-2-pyrrolidone (hereinafter, referred to as NMP) was added thereto and the solid was pulverized. Thereby, a PES aqueous dispersion having a PES concentration of about 20% was obtained. The PES particles in the PES aqueous dispersion had an average particle size of 2 μm.

Production Example 2: Preparation of Polyamide-Imide Resin Aqueous Dispersion

(3) Polyamide-imide resin (PAI) varnish (solids content: 29%, including 71% NMP) was put into water and the solid matter was pulverized in a ball mill. Thereby, a PAI aqueous dispersion was obtained. The resulting PAI aqueous dispersion had a solids content of 20%, and the PAI in the PAI aqueous dispersion had an average particle size of 2 μm.

Production Example 3

(4) First, 49.53 parts of the PES aqueous dispersion (20%) obtained in Production Example 1, 33.02 parts of the PAI aqueous dispersion (20%) obtained in Production Example 2, 15.09 parts of silicon carbide (Knoop hardness: 2500) having an average particle size of 12 μm, and 0.2% (based on the sum of the solids contents of the PES, PAI, and silicon carbide) of a polyether nonionic surfactant (polyoxyethylene tridecyl ether), serving as a dispersion stabilizer, were added to 1.72 parts of a carbon black mill base (solids content: 20%). Thereby, a primer composition P1 was obtained.

Production Example 4

(5) A primer composition P2 was prepared in the same manner as in Production Example 3 except that silicon carbide (Knoop hardness: 2500) having an average particle size of 10 μm was used instead of the silicon carbide having an average particle size of 12 μm.

Production Example 5

(6) A primer composition P3 was prepared in the same manner as in Production Example 3 except that silicon carbide (Knoop hardness: 2500) having an average particle size of 8 μm was used instead of the silicon carbide having an average particle size of 12 μm.

Production Example 6

(7) A primer composition P4 was prepared in the same manner as in Production Example 3 except that alumina (Knoop hardness: 2025) having an average particle size of 0.4 μm was used instead of the silicon carbide having an average particle size of 12 μm.

Production Example 7

(8) A primer composition P5 was prepared in the same manner as in Production Example 3 except that no silicon carbide was used.

Production Example 8

(9) First, 45.00 parts of a tetrafluoroethylene homopolymer (TFE homopolymer) aqueous dispersion (average particle size: 0.3 μm; solids content: 62%; containing, as a dispersant, a polyether nonionic surfactant (polyoxyethylene tridecyl ether) in an amount of 6% based on the TFE homopolymer), 8.69 parts of a TFE/hexafluoropropylene copolymer (FEP) aqueous dispersion (average particle size 0.17 μm; solids content: 63%; containing, as a dispersant, a polyether nonionic surfactant (polyoxyethylene tridecyl ether) in an amount of 6% based on the TFE homopolymer), 21.03 parts of the PES aqueous dispersion (20%) obtained in Production Example 1, and 7.13 parts of the PAI aqueous dispersion (20%) obtained in Production Example 2 were added to 4.19 parts of a carbon black mill base (solids content: 20%). Then, methyl cellulose in an amount of 4.4% (based on the solids content of the TFE homopolymer) was added as a thickening agent, and 4.6% (based on the sum of the solids content of the TFE homopolymer and the solids content of the FEP) of a nonionic surfactant (polyoxyethylene nonyl phenyl ether) was added as a dispersion stabilizer. Thereby, an aqueous dispersion (intermediate composition M1) having a solids content of 39.8% was obtained.

Production Example 9

(10) An intermediate composition M2 was prepared in the same manner as in Production Example 8 except that 5.29 parts of silicon carbide (Knoop hardness: 2500) having an average particle size of 15 μm was further added.

Production Example 10

(11) An intermediate composition M3 was prepared in the same manner as in Production Example 8 except that 5.29 parts of silicon carbide (Knoop hardness: 2500) having an average particle size of 21 μm was further added.

Production Example 11

(12) First, 65.65 parts of a tetrafluoroethylene homopolymer (TFE homopolymer) aqueous dispersion (average particle size: 0.3 μm; solids content: 62%; containing, as a dispersant, 6% (based on the TFE homopolymer) of a polyether nonionic surfactant (polyoxyethylene tridecyl ether)), 12.22 parts of a depolymerizable acrylic resin emulsion (butyl acrylate resin, average particle size: 0.3 μm; solids content: 40%), 1.04 parts of a polyoxyethylene tridecyl ether aqueous solution (20%), 0.84 parts of a sodium lauryl sulfate aqueous solution (25%), 0.78 parts of a thickening agent (50% ammonium oleate aqueous solution), 3.36 parts of glycerin, 2.22 parts of diethylene glycol monoethyl ether, 0.45 parts of Surfynol 104A, 1.35 parts of an antifoam (hydrocarbon solvent), 1.03 parts of carbon black mill base (20%), 0.88 parts of titanium-coated mica, and 6.77 parts of water were mixed. Thereby, a top-coat composition T1 was obtained.

Production Example 12

(13) A top-coat composition T2 was prepared in the same manner as in Production Example 11 except that 2.20 parts of silicon carbide (Knoop hardness: 2500) having an average particle size of 21 μm was further added.

Production Example 13

(14) A top-coat composition T3 was prepared in the same manner as in Production Example 11 except that 2.20 parts of silicon carbide (Knoop hardness: 2500) having an average particle size of 8 μm was further added.

Production Example 14

(15) A top-coat composition T4 was prepared in the same manner as in Production Example 11 except that 4.00 parts of glass flakes having an average particle size of 32 μm were further added.

Examples 1 to 6

(16) A surface of an aluminum plate (A-1050P) was degreased with acetone, and then roughened by sand-blasting so as to have a surface roughness Ra of 2.0 to 3.0 μm determined in conformity with JIS B0601-2001. Dusts on the surface were removed by air blowing. The primer composition P1 or P2 was spray-applied using a gravity-feed spray gun at a spraying pressure of 0.2 MPa so as to have a dry thickness of 10 to 12 μm. Then, the primer composition P1, P2, or P3 was again applied so as to have a dry thickness of 10 to 13 μm.

(17) The resulting applied film on the aluminum plate was dried at 100° C. to 150° C. for 15 minutes, and then cooled down to room temperature. Next, the maximum height roughness (Rz) was determined using a surface texture and contour measuring instrument (Surfcom 470A, Tokyo Seimitsu Co., Ltd.) in conformity with JIS B0601-2001.

(18) Next, the intermediate composition M1 was applied so as to have a thickness of 18 to 21 μm. The applied film was dried at 100° C. to 150° C. for 15 minutes, and then cooled down to room temperature.

(19) Next, one of the top-coat compositions T1 to T4 was applied so as to have a thickness of 18 to 22 μm. The applied film was dried at 100° C. to 150° C. for 15 minutes and sintered at 380° C. for 20 minutes. Thereby, a laminate of the applied films having a whole thickness of 60 to 63 μm was obtained. Table 1 shows the structures of the respective laminates in the examples.

Comparative Examples 1 to 3

(20) A surface of an aluminum plate (A-1050P) was degreased with acetone, and then roughened by sand-blasting so as to have a surface roughness Ra of 2.0 to 3.0 μm determined in conformity with JIS B0601-2001. Dusts on the surface were removed by air blowing. The primer composition P4 or P5 was spray-applied using a gravity-feed spray gun at a spraying pressure of 0.2 MPa so as to have a dry thickness of 14 to 20 μm.

(21) The resulting applied film on the aluminum plate was dried at 100° C. to 150° C. for 15 minutes, and then cooled down to room temperature. Next, the maximum height roughness (Rz) was determined using a surface texture and contour measuring instrument (Surfcom 470A, Tokyo Seimitsu Co., Ltd.) in conformity with JIS B0601-2001.

(22) Next, the intermediate composition M1, M2, or M3 was applied so as to have a thickness of 17 to 20 μm. The applied film was dried at 100° C. to 150° C. for 15 minutes, and then cooled down to room temperature.

(23) Next, the top-coat composition T1 or T2 was applied so as to have a thickness of 17 to 19 μm. The applied film was dried at 100° C. to 150° C. for 15 minutes and sintered at 380° C. for 20 minutes. Thereby, a laminate of the applied films having a whole thickness of 49 to 59 μm was obtained. Table 2 shows the structures of the respective laminates in the comparative examples.

(24) (Measurement of Thickness)

(25) In the applications of the compositions to form the respective applied films of the laminate, the respective compositions were simultaneously applied to a dummy aluminum plate (A-1050P). The thicknesses of the respective applied films formed on the dummy aluminum plate were measured, and the resulting values were treated as the thicknesses of the respective layers. Table 1 and Table 2 show the results.

(26) (Abrasion Resistance)

(27) A pad for industrial use (trade name: Scotch-Brite 7447C, 3M Co., containing alumina having a particle size of 320) was cut into a size of 3 cm square. A 1-cc portion of a 5% neutral detergent was dropped thereon, and the pad was reciprocated on the laminate at a load of 4.5 kg. For every 1000 reciprocating motions, the pad was replaced. The abrasion resistance was evaluated by the number of reciprocating motions until the substrate was exposed. Table 1 and Table 2 show the results.

(28) (Measurement of Hardness of Applied Film)

(29) The hardness measurement was performed using a pencil hardness tester equipped with a 200° C. hot stage. The hardness at which the top coat layer and the intermediate layer were separated was defined as a top coat/intermediate interface separation hardness, and the hardness at which the applied films were broken and the substrate was thus exposed was defined as a substrate separation hardness. Table 1 and Table 2 show the results. The signs 9H, 8H, 7H, 3H, 3B, 2B, 4B, and 6B in the tables mean the hardnesses of the pencils.

(30) TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Configuration Primer Type of primer composition P1 P1 P1 P2 P2 P1 of laminate layer 1 Film thickness (μm) 12 10 12 12 12 10 Composition PES Vol % 42.9 42.9 42.9 42.9 42.9 42.9 PAI Vol % 28.0 28.0 28.0 28.0 28.0 28.0 Silicon carbide Vol % 27.9 27.9 27.9 27.9 27.9 27.9 Carbon black Vol % 1.1 1.1 1.1 1.1 1.1 1.1 Primer Type of primer composition P2 P2 P2 P3 P3 layer 2 Film thickness (μm) 12 12 13 12 11 Composition PES Vol % 42.9 42.9 42.9 42.9 42.9 PAI Vol % 28.0 28.0 28.0 28.0 28.0 Silicon carbide Vol % 27.9 27.9 27.9 27.9 27.9 Carbon black Vol % 1.1 1.1 1.1 1.1 1.1 Maximum Rz (μm) 15 16 17 17 15 16 height roughness Intermediate Type of Intermediate composition M1 M1 M1 M1 M1 M1 layer Film thickness (μm) 19 21 20 20 19 18 Composition TFE Mass % 61.4 61.4 61.4 61.4 61.4 61.4 homopolymer FEP Mass % 12.0 12.0 12.0 12.0 12.0 12.0 PES Mass % 18.3 18.3 18.3 18.3 18.3 18.3 PAI Mass % 6.1 6.1 6.1 6.1 6.1 6.1 Carbon black Mass % 2.2 2.2 2.2 2.2 2.2 2.2 Top coat Type of top-coat composition T1 T2 T3 T2 T4 T2 layer Film thickness (μm) 20 19 18 19 18 22 Composition TFE Mass % 97.4 92.5 92.5 92.5 88.9 92.5 homopolymer Carbon black Mass % 0.5 0.5 0.5 0.5 0.5 0.5 Titanium- Mass % 2.1 2.0 2.0 2.0 1.9 2.0 coated mica Silicon carbide Mass % 0 5.0 5.0 5.0 0 5.0 Glass flakes Mass % 0 0 0 0 8.7 0 Whole thickness (μm) 63 62 63 63 60 60 Physical Abrasion resistance 5,000 12,000 5,000 10,000 3,000 7,000 properties of (number of reciprocating motions) film Top coat/intermediate interface separation hardness 3B 28 28 28 2B 2B (200° C.) Substrate separation hardness (200° C.) 9H 9H 9H 8H 9H 7H or higher or higher or higher or higher

(31) TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Example 1 Example 2 Example 3 Configuration Primer Type of primer composition P4 P4 P5 of laminate layer 1 Film thickness (μm) 14 15 20 Composition PES Vol % 15.5 15.5 59.6 PAI Vol % 17.9 17.9 38.9 Alumina Vol % 66.1 66.1 0 Carbon black Vol % 0.5 0.5 1.6 Maximum Rz (μm) 8 9 0.8 height roughness Intermediate Type of intermediate composition M2 M3 M1 layer Film thickness (μm) 17 18 20 Composition TFE Mass % 41.3 41.3 61.4 homopolymer FEP Mass % 20.4 20.4 12.0 PES Mass % 15.7 15.7 18.3 PAI Mass % 5.3 5.3 6.1 Silicon carbide Mass % 14.7 14.7 0 Carbon black Mass % 2.5 2.5 2.2 Top coat Type of top-coat composition T1 T1 T2 layer Film thickness (μm) 18 17 19 Composition TFE Mass % 97.4 97.4 92.5 homopolymer Carbon black Mass % 0.5 0.5 0.5 Titanium- Mass % 2.1 2.1 2.0 coated mica Silicon carbide Mass % 0 0 5.0 Whole thickness (μm) 49 50 59 Physical Abrasion resistance 10,000 12,500 5,000 properties of (number of reciprocating motions) film Top coat/intermediate interface separation hardness 4B 4B 6B (200° C.) or lower Substrate separation hardness (200° C.) 3H 3H 9H or higher

(32) Table 1 and Table 2 prove that the laminates of the applied films obtained in Examples 1 to 6 show good film performance; specifically, the abrasion resistance and the hardness are well balanced.