Coating composition excellent in abrasion resistance

Abstract

The present invention is a coating composition containing (A) a fluorine-containing copolymer and (B) a polycarbonate diol.

Claims

1. A coating composition comprising (A) a fluorine-containing copolymer and (B) a polycarbonate diol, wherein (A) is a fluorine-containing copolymer comprising a fluoroolefin in an amount of 15 to 85 mol % in all the monomer units and one or more organic silicon compounds selected from compounds represented by toe following general formulas (1) and (2) in an amount of 0.001 to 30 mol % in all the monomer units, ##STR00003## wherein R.sup.1 represents an alkyl group with 1 to 6 carbons, —(CH.sub.2).sub.r—OOC(CH.sub.3)C═CH.sub.2 or —CH═CH.sub.2, R.sup.2 represents —(CH.sub.2).sub.r—OOC(CH.sub.3)C═CH.sub.2 or —CH═CH.sub.2, n represents a number of 1 to 420, and r represents a number of 1 to 6.

2. The coating composition according to claim 1, wherein (A) is a curable fluorine-containing copolymer, and the composition comprises a curing agent for the curable fluorine-containing copolymer.

3. The coating composition according to claim 2, wherein (A) is a curable fluorine-containing copolymer having a hydroxyl group, and the curing agent for the curable fluorine-containing copolymer is a polyvalent isocyanate compound.

4. The coating composition according to claim 2, wherein the composition comprises the curing agent in an amount of 1 to 300 parts by mass relative to 100 parts by mass of (A).

5. The coating composition according to claim 1, wherein the composition comprises (A) in an amount of 1 to 90 mass %.

6. The coating composition according to claim 1, wherein the composition comprises (B) in an amount of 0.1 to 50 mass %.

7. The coating composition according to claim 1, wherein the composition comprises (B) in an amount of 1 to 300 parts by mass relative to 100 parts by mass of (A).

8. The coating composition according to claim 1, wherein (B) is a polycarbonate diol represented by the following formula (1b), ##STR00004## wherein R.sup.1b is a divalent hydrocarbon group with 2 to 20 carbons, and n is a number of 1 to 1000.

9. The coating composition according to claim 1, wherein the composition further comprises (C) a solvent.

10. The coating composition according to claim 9, wherein (C) is an organic solvent.

11. The coating composition according to claim 9, wherein the composition comprises (C) in an amount of 1 to 99 mass %.

12. A coated article comprising a substrate and a cured film of the coating composition according to claim 1 formed on the substrate.

13. The coated article according to claim 12, wherein the cured film has a film thickness of 0.1 to 100 μm.

14. The coated article according to claim 12, wherein the cured film has a 60° gloss value of 10 or less.

15. The coated article according to claim 12, wherein the substrate is formed to include a material selected from polyurethane, vinyl chloride, polyester, polyolefin, glass and metal.

16. The coated article according to claim 12, wherein the substrate is in the form of a film or a sheet.

17. A method for forming a cured film comprising, applying the coating composition according to claim 1 to a substrate to form a coating film, and curing the coating film to form a cured film.

18. The method for forming a cured film according to claim 17, wherein the cured film has a film thickness of 0.1 to 100 μm.

19. The method for forming a cured film according to claim 17, wherein the cured film has a 60° gloss value of 10 or less.

20. The method for forming a cured film according to claim 17, wherein the substrate is formed to include a material selected from polyurethane, vinyl chloride, polyester, polyolefin, glass and metal.

21. The method for forming a cured film according to claim 18, wherein the substrate is in the form of a film or a sheet.

22. The method for forming a cured film according to claim 17, wherein the curing is made by heating the coating film to 30 to 250° C.

Description

EXAMPLES

Synthesis Example 1

(1) A curable fluorine-containing copolymer was prepared in the following manner.

(2) In an autoclave (pressure resistance 10 MPa) 1 L in inner volume with a stainless stirrer after deaeration, 96 g of vinylidene fluoride (hereinafter abbreviated as VDF), 84 g of tetrafluoroethylene (hereinafter abbreviated as TFE), 14.9 g of ethyl vinyl ether (hereinafter abbreviated as EVE), 52.2 g of hydroxybutyl vinyl ether (hereinafter abbreviated as HBVE), 10.5 g of methacryl-modified silicone oil A (number average molecular weight about 3500) represented by the following structural formula, 400 ml of butyl acetate and 1.3 g of t-butyl peroxy pivalate were placed, and the inner temperature was raised to 60° C. while they were stirred.

(3) Methacryl-Modified Silicone Oil A:
CH.sub.2═C(CH.sub.3)—COO—C.sub.3H.sub.6—Si(CH.sub.3).sub.2—[O—Si(CH.sub.3).sub.2].sub.44—OSi(CH.sub.3).sub.3

(4) Thereafter, the reaction was continued while they were stirred, and 20 hours later, stirring was stopped and the reaction was finished. The resultant copolymer was isolated by drying under reduced pressure. The yield of the copolymer was 242 g and the reaction percentage of the monomers was 94%. The resultant copolymer had a hydroxyl value of 104 mgKOH/g resin measured by acetylation with acetic anhydride, a fluorine content of 47 mass % by combustion method, and a number average molecular weight of 1.9×10.sup.4 measured by GPC (gel permeation chromatography). This copolymer was dissolved in butyl acetate to form a butyl acetate solution with a concentration of 20 mass % (varnish), which was used to prepare coating compositions.

Example 1

(5) (1) Coating Composition

(6) Coating compositions containing the curable fluorine-containing copolymer, a polycarbonate diol, a solvent, a curing agent and the like in the compositions shown in the tables were prepared. Here, the components used for the coating compositions were as follows.

(7) [Component (A)] Curable fluorine-containing copolymer: curable fluorine-containing copolymer obtained in the aforementioned synthesis example 1

(8) [Curing Agent for Component (A)] Curing agent: adduct-modified product of isophorone diisocyanate (product name: TAKENATE D-140N (Mitsui Chemicals, Inc.), solids content: 75%, NCO content rate: 10.5 mass %)

(9) [Component (B)] Polycarbonate diol B1: a copolymer with a number average molecular weight of 2000 g/mol, a solids content of 100%, an OH value of 51 to 61 mgKOH/g resin and a melting point of in which the diol components are 1,3-propanediol and 1,4-butanediol, product name: DURANOL G3452 (Asahi Kasei Corporation) Polycarbonate diol B2: a copolymer with a number average molecular weight of 2000 g/mol, a solids content of 100%, an OH value of 46 to 56 mgKOH/g resin and a melting point of 5 to 15° C., in which the diol components are 1,4-butanediol and 1,6-hexanediol, product name: DURANOL G4672 (Asahi Kasei Corporation) Polycarbonate diol B3: a copolymer with a number average molecular weight of 2000 g/mol, a solids content of 100%, an OH value of 51 to 61 mgKOH/g resin and a melting point of −5° C., in which the diol components are 1,5-pentanediol and 1,6-hexanediol, product name: DURANOL T5652 (Asahi Kasei Corporation)

(10) [Component (C)] Solvent: butyl acetate

(11) [Other Components] Resin microparticle X1: organic modified polymer microparticles, average particle size: 5 μm, specific gravity: 1.25, melting point: 175° C. Resin microparticle X2: acrylic resin microparticles, average particle size: 3 μm, density (25° C.): 1.1 g/ml, refractive index: 1.49, thermal decomposition temperature: 300° C. (under nitrogen) Resin microparticle X3: fluorine resin microparticles, average particle size: 3 μm, specific gravity: 2.1 to 2.2, melting point: 310 to 320° C. Surface adjusting agent: polyester-modified silicone-based surface adjusting agent, solids content: 25%, density (20° C.) 0.92 g/ml, OH value: 35 mgKOH/g resin Silicone oil: single-end carbinol-modified product, specific gravity (25° C.): 0.97, refractive index (25° C.): 1.406, average molecular weight: 4600 g/mol, OH value: 12 mgKOH/g resin

(12) The coating compositions were prepared according to the following manner.

(13) To 100 parts by mass of the varnish made of component (A) (hydroxyl value of 104 mgKOH/g resin) in an amount of 30 mass % and component (C) as the balance, a polycarbonate diol of component (B), other components in parts by mass shown in Table 1 and further component (C) in an amount of 1131.2 parts by mass were added, and they were shaken in a paint shaker for 30 minutes. The curing agent was added thereto in an amount of 57.7 parts by mass to make each coating composition. The curing agent was added in such an amount as made NCO/OH between the hydroxyl groups (OH) of components (A) and (B) and the isocyanate group (NCO) of the curing agent 1.1 (mass ratio). The coating compositions were of the compositions shown in the tables. Note that mass % in the tables is mass % expressed in terms of an active ingredient.

(14) (2) Preparation of Coated Article

(15) Each coating composition was applied to a substrate by a bar coater (manufactured by Dai-ichi Rika, K.K., No. 16) such that the dry film thickness was 5 μm. Here, as the substrate, a commercially available wet urethane synthetic leather substrate was used. The substrate coated with the coating composition was treated by heating at 120° C. for 1 minute, and then, at 100° C. for 24 hours. Thus, a coated article (polyurethane synthetic leather subjected to matte and contamination-resistant treatment) was obtained.

(16) (3) Evaluation

(17) The following evaluations were conducted on the coated articles. The results are shown in Table 1.

(18) (3-1) 60° Gloss Value

(19) The 60° gloss value of the coating film surfaces was measured by micro-TRI-gloss (BYK Additives & Instruments) with a level of n=3.

(20) (3-2) Anti-Soiling Properties

(21) On the surface of each coated article immediately after preparation, an arbitrary figure was drawn with an oil-based ballpoint pen or an oil-based felt tipped pen, and a state after the figure was wiped off with dry tissue paper was visually observed. Here, as the oil-based ballpoint pen, ZEBRA JIM-KNOCK black ink (ZEBRA CO., LTD.) was used. Further, as the oil-based felt tipped pen, Magic Ink black ink (Teranishi Chemical Industry Co., Ltd.) was used. The removability was judged by the following criteria and evaluated as anti-soiling properties in five levels.

(22) Judgement Criteria for Removability of Black Pigment of Ink

(23) 5: the black pigment has completely been removed, and no trace of coloring matter can be seen

(24) 4: the black pigment has completely been removed, but slight traces of coloring matter can be seen

(25) 3: the black pigment has completely been removed, but traces of coloring matter can be seen

(26) 2: residual black pigment can be seen, and traces of coloring matter can also be seen

(27) 1: the black pigment has not been removed at all

(28) (3-3) Abrasion Resistance

(29) On TriboGear TYPE: 14FW Surface Property Tester (SHINTO Scientific Co., Ltd.), the surface of each coated article was abraded with canvas No. 6 under the conditions of a load of 1500 g, a rate of 6000 m/min and a moving distance of 100 mm, and the abrasion resistance thereof was evaluated on the basis of the number of round trips until the substrate was exposed. In the measurement, the abrasion treatment was performed until 3000 round trips were made, and the case where the substrate was not exposed then was taken as “more than 3000.”

(30) TABLE-US-00001 TABLE 1 Example Comparative example 1 2 3 4 5 1 2 3 4 Coating (A) Curable fluorine- 6.84 6.84 3.16 5.06 6.81 9.21 composition containing copolymer (mass %) (B) Polycarbonate diol B1 2.93 11.41 Polycarbonate diol B2 2.93 11.40 Polycarbonate diol B3 7.38 5.06 2.92 11.25 Curing agent 6.97 6.98 5.94 6.50 7.02 7.73 4.79 4.80 5.00 (C) Solvent 83.26 83.25 83.52 83.38 83.25 83.06 83.80 83.80 83.75 60° gloss value 15.3 14.0 8.1 12.1 14.0 16.2 18.7 21.7 19.1 Anti-soiling properties 5 5 4 5 5 5 2 2 2 against oil-based ballpoint pen Anti-soiling properties 4 4 4 4 4 5 2 2 2 against permanent marker Abrasion resistance 1500 1800 1400 1300 2300 1000 500 1000 1000 (number of times)

(31) TABLE-US-00002 TABLE 2 Example Comparative example 6 7 8 9 10 11 12 13 14 5 6 7 8 Coating (A) Fluorine- 2.01 3.26 4.44 2.01 3.26 4.44 2.00 3.24 4.43 7.78 compo- containing sition copolymer (mass %) (B) Polycarbonate 4.69 3.26 1.90 7.07 diol B1 Polycarbonate 4.69 3.26 1.90 7.07 diol B2 Polycarbonate 4.66 3.24 1.90 7.01 diol B3 Resin microparticle 0.67 0.65 0.64 0.67 0.65 0.64 0.67 0.65 0.63 2.33 0.71 0.71 0.70 X1 Resin microparticle 2.01 1.96 1.90 2.01 1.96 1.90 2.00 1.95 1.90 2.12 2.12 2.10 X2 Resin microparticle 0.67 0.65 0.64 0.67 0.65 0.64 0.67 0.65 0.63 0.71 0.71 0.70 X3 Surface adjusting 0.27 0.26 0.25 0.27 0.26 0.25 0.26 0.26 0.25 0.28 0.28 0.28 agent Silicone oil 2.01 1.96 1.90 2.01 1.96 1.90 2.00 1.95 1.90 2.12 2.12 2.10 Curing agent 3.87 4.31 4.73 3.87 4.31 4.73 3.96 4.37 4.76 6.52 2.97 2.98 3.12 (C) Solvent 83.80 83.69 83.60 83.80 83.69 83.60 83.78 83.69 83.60 83.37 84.02 84.01 83.99 60° gloss value 3.5 2.9 3.4 3.3 2.9 3.3 3.3 3.0 3.5 3.3 2.2 2.2 2.4 Anti-soiling properties 4 3 4 4 3 4 4 3 4 4 1 1 1 against oil-based ballpoint pen Anti-soiling properties 3 3 4 3 3 4 3 3 3 5 1 1 1 against permanent marker Abrasion resistance More 2500 2500 More 3000 More 2500 2500 3000 500 500 500 3000 (number of times) than than than 3000 3000 3000