JP2012097127A - Self-recovering coating composition and coating film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-recovering coating composition and a coating film using the same having high gloss and high transparency, not generating cracks or peeling of the coating film even after long-term use, and excellent in scratch resistance such that the scratches are not likely to remain even when being scratched.SOLUTION: The self-recovering coating composition contains (A) a lactone-modified acrylic resin and (B) polycarbonate diol. The self-recovering coating film contains the self-recovering coating composition and a polyisocyanate compound.

Description

  The present invention relates to a self-restoring coating composition and a coating film using the same.

  In recent years, surfaces such as mobile devices such as mobile phones and personal computers, automobile bodies, exterior parts, and the like are required to have high design properties and are often given high gloss and high smoothness. However, a mobile device has a problem that when it is carried, it comes into contact with other articles, causing scratches on the surface and impairing the design. Also in automobiles, scratches may occur during car washing. In particular, a surface imparted with high gloss and high smoothness is prone to scratches, and countermeasures are required.

  Therefore, for the purpose of protecting the surface, measures are taken to form a coating film using a paint having scratch resistance. For example, a hard coat coating composition containing an active energy ray-curable acrylic resin, a volatile organic acid, and alumina fine particles has been proposed (see, for example, Patent Document 1). Moreover, the method of forming the transparent cured resin layer which consists of hardened | cured material of curable resin composition containing acrylic polyol resin and a polyisocyanate compound is proposed (for example, refer patent document 2).

JP 2001-139888 A JP 2004-223893 A

  As in Patent Document 1 or Patent Document 2, the method of improving the scratch resistance by increasing the surface hardness of the coating film has a limit in improving the surface hardness of the coating film, and the scratch resistance is sufficient. I can't say that. Further, while increasing the surface hardness, the coating film tends to become brittle, and once the scratch is made, there is a problem that the scratch cannot be eliminated. Furthermore, when used for a long time, there was a problem that the coating film was cracked or peeled off.

  The object of the present invention is a self-restoring coating composition having high gloss, high transparency, no cracking or peeling of the coating film even when used for a long period of time, and excellent scratch resistance, which does not leave scratches. And a coating film using the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have focused on the relationship between the surface hardness of the coating film and the restoration property of the coating film and made the coating film hard and scratched the coating film. Instead of avoiding scratches, the coating film is given flexibility, and even if scratched, the coating film flexibility gives the scratch resistance by self-restoration that disappears and restores the original state. As a result, the present invention has been completed. In the present specification, it is defined as “self-restoring” that the coating film is flexible and returns to its original state even if the coating film is damaged. That is, the self-restoring coating composition according to the present invention is characterized by containing (A) a lactone-modified acrylic resin and (B) a polycarbonate diol.

  The self-restoring coating composition according to the present invention preferably further contains (D) an acrylic resin. The drying property of the paint can be improved.

  The self-restoring coating composition according to the present invention further comprises (D) an acrylic resin, and (A) a lactone-modified acrylic with respect to the total dry mass (A + B) of (A) a lactone-modified acrylic resin and (B) a polycarbonate diol. The resin dry mass ratio (A / (A + B)) is preferably 27/100 or more and less than 60/100. The drying property of the paint can be improved. In addition, the self-restorability can be further improved.

  The self-restoring coating composition according to the present invention preferably further contains (C) nano silica. The touch feeling of the coating film to be formed can be improved.

  The self-restoring coating film according to the present invention contains the self-restoring coating composition according to the present invention and a polyisocyanate compound.

  The present invention provides a self-restoring coating composition having high gloss, high transparency, no cracking or peeling of the coating film even when used for a long period of time, and excellent scratch resistance in which scratches do not remain. The coating film using can be provided.

  Next, the present invention will be described in detail with reference to embodiments, but the present invention is not construed as being limited to these descriptions. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

  The self-restoring coating composition according to this embodiment contains (A) a lactone-modified acrylic resin and (B) a polycarbonate diol.

  (A) A lactone-modified acrylic resin is an acrylic resin modified with a lactone and contains a hydroxyl group in the molecule. (A) The lactone-modified acrylic resin has a role of imparting basic performance such as a role of imparting self-restoring property and a physical strength of the coating film. (A) The lactone-modified acrylic resin can be usually obtained by copolymerizing a lactone-modified acrylic monomer obtained by adding a lactone to a hydroxyl group-containing acrylic monomer and another monomer that can be polymerized with the lactone-modified acrylic monomer.

  The hydroxyl group-containing acrylic monomer is, for example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate.

  Lactones include, for example, β-methyl-δ-valerolactone, γ-valerolactone, δ-valerolactone, δ-caprolactone, γ-caprolactone, ε-caprolactone, β-propiolactone, γ-butyrolactone, and γ-nonano. Ic lactone, δ-dodecanolactone. Furthermore, a functional group such as an alkyl group, an alkoxy group, a cycloalkyl group, a phenyl group, or a benzyl group can be further bonded to the ring carbon atom of the lactone.

  A method for adding a lactone to a hydroxyl group-containing acrylic monomer is not particularly limited, and a known method can be adopted. A known method is, for example, a method in which ε-caprolactone is reacted with a hydroxyl group-containing acrylic monomer in the presence of a catalyst.

  Other monomers polymerizable with the lactone-modified acrylic monomer include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) Acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, (meth) acrylate esters such as 2-ethylexyl (meth) acrylate, carboxyl group-containing monomers such as (meth) acrylic acid, styrene, α- Styrene derivatives such as methylstyrene, vinyltoluene, paramethylstyrene, chlorostyrene, vinyl esters such as vinyl acetate and vinyl propionate, vinyl halide monomers such as vinyl chloride and vinylidene chloride, acrylamide, diacetone Acrylamide, N- methylol acrylamide, acrylonitrile, methacrylamide, a nitrogen-containing vinyl monomers such as methacrylonitrile. Any of these may be used alone or in appropriate combination of two or more. This embodiment is not limited to the type of monomer and polymerization method.

  The (A) lactone-modified acrylic resin preferably has an ether bond in the molecule. The lactone-modified acrylic resin having an ether bond in the molecule can be obtained by copolymerizing the lactone-modified acrylic monomer and a monomer that can be polymerized with the lactone-modified acrylic monomer and has an ether bond in the molecule. Monomers having an ether bond in the molecule are, for example, 2-methoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxy polyethylene glycol (Meth) acrylate, methoxypolypropylene glycol (meth) acrylate, and tetrahydrofurfuryl (meth) acrylate. Any of these may be used alone or in appropriate combination of two or more. This embodiment is not limited to the type of monomer and polymerization method. Further, as the (A) lactone-modified acrylic resin, a commercially available product such as a registered trademark Planet TC Clear CF-100 manufactured by Origin Electric Co., Ltd. can be used.

  (A) The number average molecular weight of the lactone-modified acrylic resin is preferably 6000 to 25000. More preferably, it is 8000-15000. If it is less than 6000, the strength of the coating film may be insufficient. When it exceeds 25000, the viscosity of the coating becomes too high, and a uniform coating may not be obtained. Or the smoothness of a coating film may be inferior.

  (A) It is preferable that the glass transition point of a lactone modified acrylic resin is 0-25 degreeC. More preferably, it is 10-17 degreeC. If it is less than 0 degreeC, a coating film may become too soft and a self-restoration property may be inferior. Moreover, the heat resistance of a coating film may be inferior. When it exceeds 25 degreeC, a coating film may become hard too much and a self-restoration property may be inferior.

  (A) The hydroxyl value of the lactone-modified acrylic resin is preferably 90 to 110 mgKOH / g. More preferably, it is 95-105 mgKOH / g. If it is less than 90 mgKOH / g, the coating film becomes too hard and the self-restoring property may be inferior. Moreover, there are cases where the crosslinking reaction point is insufficient and the water resistance and chemical resistance of the coating film are poor. When it exceeds 110 mgKOH / g, the coating film becomes too soft and the self-restoring property may be inferior. Moreover, the curing shrinkage by a crosslinking reaction is large, and adhesiveness with a base material may be inferior.

  The self-restoring coating composition preferably contains (A) a lactone-modified acrylic resin in a dry mass of 25 to 85% by mass. More preferably, it is 33-72 mass%. Most preferably, it is 50-60 mass%. If it is less than 25 mass%, the physical strength of the coating film may be insufficient. Moreover, drying property may be inferior. If it exceeds 85% by mass, the coating film becomes too hard and the self-restoring property and scratch resistance may be inferior.

  (B) Polycarbonate diol is a compound having a plurality of polycarbonate bonds (—OCOO—) and two hydroxyl groups. It is preferable that both ends are hydroxyl groups. (B) Polycarbonate diol is mix | blended for the purpose of providing self-restoration property, adhesiveness with a base material, glossiness of a coating film, and smoothness. (B) The method of obtaining polycarbonate diol is not specifically limited, It can obtain by a well-known method. A known method is, for example, a transesterification reaction between a diol and a carbonate ester.

  Examples of the diol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl- 1,5-pentanediol and 1,6-hexanediol. Carbonic acid esters are, for example, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, and diaryl carbonates such as diphenyl carbonate. Any of these may be used alone or in appropriate combination of two or more. Moreover, as (B) polycarbonate diol, commercial items, such as a brand name Duranol T-5650J by Asahi Kasei Chemicals, can be used.

  (B) The number average molecular weight of the polycarbonate diol is preferably 800 to 2,000. More preferably, it is 800-1600. If it is less than 800, a coating film may become too soft and a self-restoration property may be inferior. When 2000 is exceeded, compatibility may fall and the smoothness of a coating film may be inferior. Moreover, the gloss of a coating film may be inferior.

  (B) The hydroxyl value of the polycarbonate diol is preferably 100 to 170 mgKOH / g. More preferably, it is 130-150 mgKOH / g. If it is less than 100 mgKOH / g, the gloss may be inferior. Moreover, there are cases where the crosslinking reaction point is insufficient and the water resistance and chemical resistance of the coating film are poor. When it exceeds 170 mgKOH / g, the coating film becomes too soft and the self-restoring property may be inferior. Moreover, the curing shrinkage by a crosslinking reaction is large, and the adhesiveness to a base material may be inferior.

  The self-restoring coating composition preferably contains (B) polycarbonate diol in a dry mass of 15 to 75% by mass. More preferably, it is 28-59 mass%. Most preferably, it is 40-50 mass%. If it is less than 15% by mass, the self-restorability and scratch resistance may be inferior. If it exceeds 75% by mass, the coating film strength may be insufficient.

  In the self-restoring coating composition according to this embodiment, the total dry mass of (A) the lactone-modified acrylic resin and (B) the polycarbonate diol is preferably 60% by mass or more. More preferably, it is 70 mass% or more. Especially preferably, it is 80 mass% or more. If it is less than 65% by mass, the self-restoring property and the scratch resistance may be inferior. Moreover, the physical strength of the coating film may be insufficient.

  The ratio of the content of (A) lactone-modified acrylic resin to the total content of (A) lactone-modified acrylic resin and (B) polycarbonate diol (A / (A + B)) is 85/100 or less in terms of dry mass. Is preferred. More preferably, it is less than 60/100. When it exceeds 85/100, the coating film becomes too hard and the self-restoring property may be inferior.

  In the self-restoring coating composition according to this embodiment, it is preferable to further contain (D) an acrylic resin. (D) The acrylic resin has a role of improving the drying property of the paint. (D) Acrylic resin is a polymer of a hydroxyl group-containing acrylic monomer exemplified in (A) Lactone-modified acrylic resin, or a copolymer of monomers exemplified as other hydroxyl group-containing acrylic monomers and other monomers polymerizable with lactone-modified acrylic monomers. It is a coalescence.

  When the ratio of (A) lactone-modified acrylic resin and (B) polycarbonate diol is a predetermined ratio, the present inventors further blended (D) acrylic resin, thereby improving the drying property and self-restoring. It has been found that there is a new effect of improving the performance. The self-restoring coating composition according to this embodiment further comprises (D) an acrylic resin, and (A) lactone modification with respect to the total dry mass (A + B) of (A) lactone-modified acrylic resin and (B) polycarbonate diol. It is preferable that the ratio (A / (A + B)) of the dry mass of the acrylic resin is 27/100 or more and less than 60/100. More preferably, it is 27.8 / 100 or more and 50/100 or less. Particularly preferably, it is 34.5 / 100 or more and 42/100 or less.

  (D) It is preferable that the number average molecular weights of an acrylic resin are 4000-100000. More preferably, it is 6000-50000. If it is less than 4000, the effect which improves a drying property may be inferior. If it exceeds 100,000, the paint may become cloudy and the transparency may be inferior. In addition, the viscosity of the paint may become too high to obtain a uniform paint.

  (D) It is preferable that the glass transition point of an acrylic resin is 40-60 degreeC. More preferably, it is 50-55 degreeC. If it is less than 40 degreeC, the effect which improves drying property may be inferior. Moreover, the effect which improves self-restoration property may be inferior. When it exceeds 60 ° C., the coating film becomes too hard and the self-restoring property may be inferior.

  (D) It is preferable that the hydroxyl value of an acrylic resin is 60-80 mgKOH / g. More preferably, it is 65-75 mgKOH / g. If it is less than 60 mgKOH / g, a coating film may become hard and self-restoration property may be inferior. If it exceeds 80 mgKOH / g, the drying property may be inferior due to the unreacted hydroxyl group. Moreover, water resistance and chemical resistance may be inferior.

  (D) In order to obtain the effect of improving the drying property by blending the acrylic resin, (D) the acrylic resin is added to the dry total mass of 100 parts by mass of (A) the lactone-modified acrylic resin and (B) the polycarbonate diol. On the other hand, it is preferable to contain 5-15 mass parts by dry mass. More preferably, it is 6-9 mass parts. If it is less than 5 parts by mass, the effect of improving the drying property may be inferior. If it exceeds 15 parts by mass, the scratch resistance may be inferior. Particularly preferably, the ratio (A / (A + B)) of the dry mass of (A) lactone-modified acrylic resin to the total dry mass (A + B) of (A) lactone-modified acrylic resin and (B) polycarbonate diol is 27/100 or more. It is less than 60/100, and (D) acrylic resin is contained in an amount of 5 to 13 parts by mass in dry mass with respect to 100 parts by mass of dry mass of (A) lactone-modified acrylic resin and (B) polycarbonate diol. More preferably, it contains 5.5-9 mass parts. Thereby, in addition to the effect of improving the drying property, the effect of improving the self-restoring property can be further obtained.

  The self-restoring coating composition according to this embodiment preferably further contains (C) nanosilica. (C) Nano silica has a role of improving the touch of the coating film to be formed. Here, the state where the tactile sensation is good refers to a smooth state without receiving a feeling of resistance such as stickiness (tackiness) or roughness when the coating film is touched with a finger. On the other hand, the state where the tactile sensation is bad refers to a state where there is a feeling of resistance such as stickiness or roughness when the coating film is touched with a finger.

  (C) The nanosilica is preferably fine particles having a core-shell structure composed of an inorganic silicon dioxide-based core and a polyacrylate shell composed of a reactive hydroxyl group. Nano silica can be used as a dispersion dispersed in a dispersion medium. The dispersion has a sharp particle size distribution and exists as primary particles in which fine particles are individually dispersed without agglomeration.

  (C) It is preferable that the average particle diameter of nano silica is 1-100 nm. More preferably, it is 2 to 40 nm. If it is less than 2 nm, transparency may be inferior due to aggregation. When it exceeds 100 nm, the surface of the coating film may be uneven, and the tactile sensation may be deteriorated. As (C) nanosilica, a commercial product such as a trade name Tivida AS-1010 manufactured by Merck & Co., Inc. can be used.

  The self-restoring coating composition may contain (C) nanosilica in an amount of 0.5 parts by mass or more by dry mass relative to 100 parts by mass of dry mass of (A) lactone-modified acrylic resin and (B) polycarbonate diol. preferable. More preferably, it is 1.0 part by mass or more. If the amount is less than 0.5 parts by mass, the effect of enhancing the touch may be inferior. Moreover, it is preferable that the upper limit of content of (C) nano silica shall be 2.0 mass parts. More preferably, it is 1.5 parts by mass. If it exceeds 2.0 parts by mass, it becomes excessive and uneconomical.

  The self-restoring coating film according to the present embodiment contains the self-restoring coating composition according to the present embodiment and a polyisocyanate compound. The polyisocyanate compound acts as a crosslinking agent. A polyisocyanate compound is a compound having two or more isocyanate groups in one molecule. Any of these may be used alone or in appropriate combination of two or more.

  Examples of the polyisocyanate compound include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates. Aliphatic polyisocyanates include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene. Diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate.

  Examples of alicyclic polyisocyanates include 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, and 1,4-cyclohexane. Diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate) (hydrogenated MDI), 1,4-bis (isocyanatemethyl) cyclohexane.

  Aromatic polyisocyanates include, for example, 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6- Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 "-Triphenylmethane triisocyanate.

  Examples of the araliphatic polyisocyanate include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate and 1,3-tetramethylxylylene diisocyanate.

  In this embodiment, it is preferable to use an aliphatic polyisocyanate or an alicyclic polyisocyanate as the polyisocyanate compound from the viewpoint of non-yellowing. More preferably, it is a trimer of an aliphatic polyisocyanate or an alicyclic polyisocyanate, and is a biuret type or isocyanurate type polyisocyanate. Particularly preferred is HDI isocyanurate. A commercial item can be used as an isocyanate compound. Commercially available products are, for example, product name Duranate TPA-100 manufactured by Asahi Kasei Chemicals, which is an isocyanurate type polyisocyanate, product name Duranate TLA-100 manufactured by Asahi Kasei Chemicals, manufactured by Asahi Kasei Chemicals, Inc., which is a biuret type polyisocyanate. There is a trade name Duranate 24A-100.

  The content of the polyisocyanate compound is such that the molar equivalent of the isocyanate group (—NCO) to the molar equivalent 1 of the hydroxyl group (—OH) contained in the self-restoring coating composition is more than 0.9 and less than 1.5. preferable. More preferably, it is 1.0 or more and 1.2 or less. When the molar equivalent of the isocyanate group is 0.9 or less with respect to the molar equivalent of 1 of the hydroxyl group, the coating film strength may be inferior. Moreover, drying property may be inferior. When the molar equivalent of the isocyanate group is 1.5 or more with respect to the molar equivalent of 1 of the hydroxyl group, the restoring property may be inferior. Here, the molar equivalent of the hydroxyl group contained in the self-restoring coating composition is the total molar equivalent of the hydroxyl group of (A) the lactone-modified acrylic resin and (B) the polycarbonate diol. Alternatively, when (D) an acrylic resin is contained, the molar equivalent of the hydroxyl group contained in the self-restoring paint is the sum of the hydroxyl groups of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin. Molar equivalent.

  The paint for forming the self-restoring coating film according to this embodiment (hereinafter referred to as “self-restoring paint”) is a two-component curing type having the self-restoring coating composition according to this embodiment as a main agent and a polyisocyanate compound as a curing agent. It is a paint. The self-restoring coating film according to the present embodiment is prepared by blending the main agent and the curing agent, and applying a self-restoring paint prepared to a solid content concentration suitable for coating with an organic solvent on a base material and then drying. Can be formed.

  Examples of the organic solvent include diethyl ketone (3-pentanone), methyl propyl ketone (2-pentanone), methyl isobutyl ketone (4-methyl-2-pentanone), 2-hexanone, 5-methyl-2-hexanone, 2- Ketones such as heptanone, 3-heptanone, 4-heptanone, cyclopentanone, cyclohexanone, ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, 3-methoxybutyl acetate, methyl propionate, propionate These are esters such as ethyl acid, diethyl carbonate, γ-butyrolactone, isophorone and butyl isobutyrate, hydrocarbons such as heptane, hexane and cyclohexane, and aromatic hydrocarbons such as toluene and xylene. Furthermore, an aqueous medium may be used to further reduce the environmental load. An aqueous medium is a mixture of water and a hydrophilic organic solvent. Examples of hydrophilic organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, Alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethers such as tetrahydrofuran and 1,4-dioxane, ketones such as acetone and methyl ethyl ketone, methyl acetate, acetic acid -Esters such as n-propyl, isopropyl acetate, methyl propionate, ethyl propionate, and dimethyl carbonate. In this embodiment, it is not restricted to the kind of liquid solvent, Arbitrary 1 type can be used individually or in combination of 2 or more types as appropriate.

  Although a base material is not specifically limited, For example, polyacetal (POM), polyamide (PA), polycarbonate (PC), polyphenylene ether (PPE), polybutylene terephthalate (PBT), acrylonitrile butadiene styrene copolymer (ABS), poly They are methyl methacrylate (PMMA) and polypropylene (PP). In addition, a base coat serving as a coloring layer can be provided on the base material, and the self-restoring coating film according to the present embodiment can be provided on the base coat. By providing a self-restoring coating film on the base coat, the unevenness of the base coat can be filled and high gloss and high smoothness can be imparted.

  The method for applying the self-restoring paint is not particularly limited, and is a known method such as a brush coating method, a roller coating method, a spraying method using a spray gun, a roll coater method, or a dipping method. The drying method is not particularly limited, and for example, natural drying or forced drying with hot air.

  The thickness of the self-restoring coating film is preferably 10 to 40 μm. More preferably, it is 15-20 micrometers. If it is less than 10 micrometers, smoothness may be inferior. If it is 40 μm or more, it is uneconomical.

The Martens hardness of the self-restoring coating film is preferably ¹ to 30 N / mm ² . More preferably, it is 3 to 10 N / mm ² . Martens hardness is the hardness of the coating film obtained from the quotient of the test load when the indenter is pressed into the surface of the coating film and the surface area of the dent generated by the pressing, and is an index of the hardness of the object surface. If it is less than 1 N / mm ² , the surface of the coating film may be too soft and inferior in self-restoring properties. If it exceeds 30 N / mm ² , the surface of the coating film may be too hard and may be inferior in self-restoring properties.

  Restorability is deformed by receiving a load, but when the load is removed, it returns to its original state, and it is deformed by receiving a load with an instantaneous resilience that is not apparently deformed (not damaged), Although deformation (scratches) remains even after the load is removed, there is “self-restoring” as used in the present specification, where the deformation is restored within a predetermined time. However, conventionally, in the evaluation of the resilience of a self-restoring coating film or plastic substrate, the judgment of “restoring” is often the subjective judgment of each individual, and the evaluation method has been established. Absent. Therefore, the present inventors have established a method for evaluating the restorability. As a method for evaluating the resilience, first, the plastic deformation work Wp is roughly used as an index for evaluating the instantaneous resilience, and then the restoration rate is used as an index for evaluating the self-restorability. It is a method to evaluate. By this method, the restoration property of the coating film can be objectively evaluated regardless of the restoration speed. The restoration rate can be obtained by Equation 1.

(Equation 1) Restoration rate [%] = (d1-d2) / (d1-d0) × 100
In Equation 1, d1 [μm] is the depth immediately after the end of the load reduction, and d2 [μm] is the depth 60 seconds after the end of the load reduction. d0 [μm] is the starting point depth.

  In Formula 1, the depth d1 immediately after the end of load reduction is determined by using a Martens hardness tester to push a square pyramidal diamond indenter into the surface of the coating film so that the maximum load is 10 mN over 20 seconds. After holding the load for 5 seconds, the load is reduced and the indenter is separated from the surface of the coating over 60 seconds. When the surface of the coating is separated from the indenter, the load reduction is completed. Is the depth of the indentation. The depth d2 60 seconds after the end of the load reduction is the depth of the dent 60 seconds after the end of the load reduction. The starting point depth d0 is the height of the coating film surface before applying a load.

  It shows that the smaller the value of the plastic deformation work Wp, the higher the instantaneous restoration property and the less the influence from the outside. On the contrary, the larger the value of the plastic deformation work Wp is, the lower the instantaneous restoration property is, and it is easy to be influenced from the outside. In addition, the larger the value of the restoration rate, the greater the force with which a scratch once attached is restored over time, indicating that the self-restoring property is higher. On the other hand, the smaller the value of the restoration rate, the harder the damage once attached is, or it does not return to its original state over time, indicating that the self-restoring property is low.

  The restoration rate of the self-restoring coating film according to this embodiment is preferably 30% or more. More preferably, it is 50% or more.

  The haze value of the self-restoring coating film according to this embodiment is preferably 15% or less. More preferably, it is 8% or less. If the haze value exceeds 15%, the transparency may be inferior. Further, according to JIS K 7204: 1999 “Plastics—Abrasion Test Method Using Wear Wheels”, a haze value (H2) after a wear test in which a wear wheel is rotated 1000 times at a load of 9.8 N and a rotation speed of 60 rpm, and a haze value before the wear test The difference from (H1) (ΔH = H2−H1) is preferably less than 20%. More preferably, it is less than 10%, and particularly preferably less than 6%.

  Next, although an example of the present invention is given and explained, the present invention is not limited to these examples. Unless otherwise specified, the number of added parts is a value in terms of solid content.

Example 1
(A) Lactone modified acrylic resin (registered trademark Planet TC Clear CF-100, manufactured by Origin Electric Co., Ltd.) 84.4 parts by mass and (B) polycarbonate diol (trade name Duranol T-5650J, manufactured by Asahi Kasei Chemicals Co., Ltd.) 15.6 masses Self-restoring coating composition containing 2 parts by weight and a polyisocyanate compound (trade name Duranate TPA-100, manufactured by Asahi Kasei Chemicals) 27.4 parts by weight with ethyl acetate to a solid content concentration of 39.9% Was prepared. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin and (B) polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1. The self-restoring paint was applied to the surface of the base material (material: ABS, thickness 1 mm) using a spray gun so that the thickness of the coating film after drying was 15 μm. The obtained coated surface was left to stand for 30 minutes in a drying oven at 80 ° C. and dried to form a self-restoring coating film.

(Example 2)
In Example 1, the blending amount of (A) the lactone-modified acrylic resin was changed to 71.3 parts by mass, the blending amount of (B) the polycarbonate diol was changed to 28.7 parts by mass, and the blending amount of the polyisocyanate compound was 26. A self-restoring coating film was formed in the same manner as in Example 1 except that the amount was changed to 3 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin and (B) polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 3)
In Example 1, the blending amount of (A) the lactone-modified acrylic resin was changed to 60.0 parts by mass, the blending amount of (B) the polycarbonate diol was changed to 40.0 parts by mass, and the blending amount of the polyisocyanate compound was 25. A self-restoring coating film was formed in the same manner as in Example 1 except that the amount was changed to 3 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin and (B) polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1.

Example 4
In Example 1, the blending amount of (A) lactone-modified acrylic resin was changed to 50.4 parts by mass, the blending amount of (B) polycarbonate diol was changed to 49.6 parts by mass, and the blending amount of the polyisocyanate compound was 24. A self-restoring coating film was formed in the same manner as in Example 1 except that the amount was changed to 5 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin and (B) polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 5)
In Example 1, the blending amount of (A) lactone-modified acrylic resin was changed to 41.9 parts by mass, the blending amount of (B) polycarbonate diol was changed to 58.1 parts by mass, and the blending amount of the polyisocyanate compound was 23. A self-restoring coating film was formed in the same manner as in Example 1 except that the amount was changed to 8 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin and (B) polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 6)
In Example 1, the blending amount of (A) the lactone-modified acrylic resin was changed to 34.5 parts by mass, the blending amount of (B) the polycarbonate diol was changed to 65.5 parts by mass, and the blending amount of the polyisocyanate compound was 23. A self-restoring coating film was formed in the same manner as in Example 1 except that the amount was changed to 2 parts by mass. The molar equivalent ratio of (A) the hydroxyl group of the lactone-modified acrylic resin and (B) the hydroxyl group of the polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 7)
In Example 1, the blending amount of (A) lactone-modified acrylic resin was changed to 27.8 parts by mass, the blending amount of (B) polycarbonate diol was changed to 72.2 parts by mass, and the blending amount of the polyisocyanate compound was 22 A self-restoring coating film was formed in the same manner as in Example 1 except that the amount was changed to 5 parts by mass. The molar equivalent ratio of (A) the hydroxyl group of the lactone-modified acrylic resin and (B) the hydroxyl group of the polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 8)
In Example 1, (A) lactone-modified acrylic resin (trade name Planet TC Clear CF-100, manufactured by Origin Electric Co., Ltd.) 36.0 parts by mass, (B) polycarbonate diol (trade name, Duranol T-5650J, manufactured by Asahi Kasei Chemicals Corporation) ) 64.0 parts by mass and (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.), 8.9 parts by mass, a self-restoring coating composition, and a polyisocyanate compound (trade name: Duranate TPA- 100, manufactured by Asahi Kasei Chemicals Co., Ltd.) A self-restoring coating film was formed in the same manner as in Example 1 except that 24.9 parts by mass were diluted with ethyl acetate to prepare a self-restoring coating material having a solid content concentration of 53.2%. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

Example 9
In Example 3, 7.5 parts by mass of (D) acrylic resin (trade name Dainar LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further added to the self-restoring coating composition, and the compounding amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 3 except that the amount was changed to 26.7 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 10)
In Example 4, 6.9 parts by mass of (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further added to the self-restoring coating composition, and the compounding amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 4 except that the amount was changed to 25.8 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 11)
In Example 5, 6.5 parts by mass of (D) acrylic resin (trade name: Dainar LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further added to the self-restoring coating composition, and the compounding amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 5 except that the amount was changed to 25.0 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 12)
In Example 6, 6.1 parts by mass of (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further added to the self-restoring coating composition, and the compounding amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 6 except that the amount was changed to 24.3 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 13)
In Example 7, 5.8 parts by mass of (D) acrylic resin (trade name: Dainar LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further blended with the self-restoring coating composition, and the blending amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 7 except that the amount was changed to 23.6 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 14)
In Example 3, 14.7 parts by mass of (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further blended with the self-restoring coating composition, and the blending amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 3 except that the amount was changed to 28.0 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 15)
In Example 4, 13.6 parts by mass of (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further blended with the self-restoring coating composition, and the blending amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 4 except that the content was changed to 27.1 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 16)
In Example 5, 12.8 parts by mass of (D) acrylic resin (trade name: Dainar LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further blended with the self-restoring coating composition, and the blending amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 5 except that the amount was changed to 26.1 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 17)
In Example 6, 12.0 parts by mass of (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further added to the self-restoring coating composition, and the compounding amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 6 except that the amount was changed to 25.4 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 18)
In Example 7, 11.3 parts by mass of (D) acrylic resin (trade name: Dianal LR-1711, manufactured by Mitsubishi Rayon Co., Ltd.) is further added to the self-restoring coating composition, and the compounding amount of the polyisocyanate compound is A self-restoring coating film was formed in the same manner as in Example 7 except that the amount was changed to 24.6 parts by mass. The molar equivalent ratio of the hydroxyl group of (A) lactone-modified acrylic resin, (B) polycarbonate diol and (D) acrylic resin to the isocyanate group of the polyisocyanate compound was 1: 1.

(Example 19)
In Example 8, a self-restoring coating film was formed in the same manner as in Example 8 except that 0.5 part by mass of (C) nanosilica (trade name Tibida AS-1010, manufactured by Merck & Co., Inc.) was further added to the self-restoring paint. did. (C) The average particle diameter of nano silica was 9 nm.

(Example 20)
In Example 19, a self-restoring coating film was formed in the same manner as in Example 19 except that the amount of (C) nanosilica was changed to 1.0 part by mass.

(Example 21)
In Example 19, a self-restoring coating film was formed in the same manner as in Example 19 except that the amount of (C) nanosilica was changed to 1.5 parts by mass.

(Example 22)
In Example 19, a self-restoring coating film was formed in the same manner as in Example 19 except that the amount of (C) nanosilica was changed to 2.0 parts by mass.

(Comparative Example 1)
(A) 100 parts by mass of a lactone-modified acrylic resin (trade name Planet TC Clear CF-100, manufactured by Origin Electric Co., Ltd.) and 72 parts by mass of a polyisocyanate compound (trade name: Duranate TPA-100, manufactured by Asahi Kasei Chemicals) with ethyl acetate A paint having a solid content of 37.2% was prepared by dilution. Here, the molar equivalent ratio of (A) the hydroxyl group of the lactone-modified acrylic resin and the isocyanate group of the polyisocyanate compound was 1: 1. This paint was applied to the surface of the base material (material: ABS, thickness 1 mm) using a spray gun so that the thickness of the coating film after drying was 20 μm. The obtained coated surface was left to stand for 30 minutes in an oven at 80 ° C. and dried to form a coating film.

(Comparative Example 2)
(B) 100 parts by mass of a polycarbonate diol (trade name Duranol T-5650J, manufactured by Asahi Kasei Chemicals) and 32.4 parts by mass of a polyisocyanate compound (trade name Duranate TPA-100, manufactured by Asahi Kasei Chemicals) were diluted with ethyl acetate. Thus, a paint having a solid content concentration of 69.1% was prepared. Here, the molar equivalent ratio of the hydroxyl group of (B) polycarbonate diol to the isocyanate group of the polyisocyanate compound was 1: 1. This paint was applied to the surface of the base material (material: ABS, thickness 1 mm) using a spray gun so that the thickness of the coating film after drying was 20 μm. The obtained coated surface was allowed to stand for 30 minutes in a drying oven at 80 ° C. and dried, but a coating film could not be formed.

(Reference Example 1)
In Example 19, in place of 0.5 parts by mass of (C) nanosilica in self-restoring paint, 0.6 parts by mass of alumina particles (trade name NANOBYK (registered trademark) -3601, manufactured by Big Chemie Japan) was blended. Formed a self-restoring coating film in the same manner as in Example 19. The average particle diameter of the alumina particles was 40 nm.

(Reference Example 2)
In Example 19, (C) Nanosilica 0.5 parts by mass was replaced with 0.9 parts by mass of alumina particles (trade name NANOBYK (registered trademark) -3601, manufactured by Big Chemie Japan) in place of 0.5 parts by mass of nanosilica. Formed a self-restoring coating film in the same manner as in Example 19. The average particle diameter of the alumina particles was 40 nm.

(Reference Example 3)
In Example 19, in place of 0.5 parts by mass of (C) nanosilica in self-recovering paint, 0.5 parts by mass of silica particles (trade name NANOBYK (registered trademark) -3650, manufactured by Big Chemie Japan) was blended. Formed a self-restoring coating film in the same manner as in Example 19. The average particle diameter of the silica particles was 20 to 25 nm.

(Reference Example 4)
In Example 19, in place of 0.5 part by mass of (C) nanosilica in self-recovering paint, 0.75 part by mass of silica particles (trade name NANOBYK (registered trademark) -3650, manufactured by Big Chemie Japan) was blended. Formed a self-restoring coating film in the same manner as in Example 19. The average particle diameter of the silica particles was 20 to 25 nm.

(Reference Example 5)
In Example 19, the self-restoring paint (C) was replaced with 0.5 parts by mass of nanosilica, except that 0.8 parts by mass of zinc oxide (trade name NANOBYK (registered trademark) -3821, manufactured by Big Chemie Japan) was blended. Formed a self-restoring coating film in the same manner as in Example 19. The average particle diameter of zinc oxide was 20 nm.

(Reference Example 6)
In Example 19, in place of 0.5 parts by mass of (C) nanosilica in the self-restoring paint, except that 1.2 parts by mass of zinc oxide (trade name NANOBYK (registered trademark) -3821, manufactured by Big Chemie Japan) was blended Formed a self-restoring coating film in the same manner as in Example 19. The average particle diameter of zinc oxide was 20 nm.

(Reference Example 7)
In Example 19, Example 19 except that 0.5 part by mass of silicate (trade name JC-21, manufactured by Mizusawa Chemical Co., Ltd.) was blended in the self-restoring paint in place of 0.5 part by mass of (C) nanosilica. A self-restoring coating film was formed in the same manner as above. The average particle size of the silicate was 2.0 nm.

(Reference Example 8)
In Example 19, in place of 0.5 parts by mass of (C) nano silica in the self-restoring paint, 0.5 parts by mass of polyethylene resin (trade name Microflat CE-502, manufactured by Koyo Chemical Co., Ltd.) was blended. A self-restoring coating film was formed in the same manner as in Example 19. The average particle size of polyethylene was 10 nm.

  Table 1 shows the compositions of the obtained self-restoring coating films of Examples and Reference Examples and the coating films of Comparative Examples. Moreover, the following method evaluated the self-restoration coating film of the obtained Example, and the coating film of a comparative example. The evaluation results are shown in Tables 2 to 4.

(Surface hardness of coating film-Martens hardness)
The surface hardness of the coating film was evaluated as Martens hardness. Martens hardness was measured using a Martens hardness meter (model FISCHERSCORPE H100C, manufactured by Fisher Instruments). The Martens hardness values are shown in Table 2.

(Instantaneous Restoration Evaluation-Plastic Deformation Work Wp)
The instantaneous restoration property of the coating film was evaluated by the plastic deformation work Wp. The plastic deformation work Wp was measured using a Martens hardness measuring instrument (model FISCHERSCORPE H100C, manufactured by Fisher Instruments). Table 2 shows values of the plastic deformation work Wp.

(Self-restoration evaluation-Restoration rate)
The self-restoring property of the coating film was evaluated by the restoration rate. Using a Martens hardness tester (model FISCHERSCORPE H100C, manufactured by Fischer Instruments), apply a pyramid diamond indenter to the surface of the coating so that the maximum load is 10 mN over 20 seconds. After being pushed in and held for 5 seconds with the same load, the restoration rate when the load was reduced and the indenter was separated from the surface of the coating film over 60 seconds was determined from Equation 1. Table 2 shows the values of the restoration rate.

(Abrasion resistance evaluation)
One of the base materials on which the self-restoring coating film of the example to be evaluated or the coating film of the comparative example was formed and the base material on which the coating film in the control section was formed side by side, and the surface of both coating films was brass. 50 reciprocations with a brush. After standing for 60 seconds, the surface states of both coatings were compared. As a control group, a two-component acrylic urethane paint (product surface: Econet NS, manufactured by Origin Electric Co., Ltd.) is used on the surface of the base material (material: ABS, thickness 5 mm) with a spray gun, A coating film was used that was formed so as to have a thickness of 20 μm, and the obtained coated surface was left to stand in a drying furnace at 80 ° C. for 30 minutes to dry. The evaluation criteria are as follows. The evaluation results are shown in Table 2.
A: Less scratches than the control group (practical level).
○: Equivalent to the control group (practical level).
(Triangle | delta): Although there are some scratches rather than a control section, it can be used practically (practical use lower limit level).
X: There are much more scratches than the control group, which is a problem in practical use (not practical).

(Glossiness evaluation)
The glossiness of the coating film was evaluated by the glossiness. The glossiness was measured using a gloss meter (model micro-TRI-gloss, manufactured by BYK). The evaluation results are shown in Table 3. Glossiness means that the greater the value, the higher the gloss.

(Transparency evaluation-haze value)
The transparency of the coating film was evaluated using the haze value (H1). The haze value (H1) was measured using a haze meter (model NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.). A case where H1 was 15% or less was regarded as a practical level, and a case where H1 exceeded 15% was regarded as unsuitable for practical use. The evaluation results are shown in Table 3.

(Abrasion resistance evaluation)
Measure the haze value before and after the Taber abrasion test in accordance with JIS K 7204: 1999 “Plastics—Abrasion test method with wear wheel”, and the difference between the haze value before the test (H1) and the haze value after the test (H2) (ΔH ) Was calculated and scratch resistance was evaluated. In the Taber abrasion test, a wear wheel was rotated 1000 times on the coating film at a load of 9.8 N and a rotation number of 60 rpm using a Taber abrasion tester (model 60 RPM, Taber type, manufactured by Toyo Seiki Co., Ltd.). A case where ΔH was 20% or less was regarded as a practical level, and a case where ΔH exceeded 20% was regarded as unsuitable for practical use. The evaluation results are shown in Table 3.

(Dryness evaluation)
After coating the coating material on the substrate, the time required from putting in the drying oven under the above conditions (atmosphere temperature 80 ° C.) to drying by touch was evaluated as drying property. In addition, finger touch drying means a state in which the fingertip is not soiled by lightly touching the center of the coating film with the fingertip (JIS K5600-1-1: 1999). The evaluation criteria are as follows. The evaluation results are shown in Table 3.
A: Time until stickiness disappears is 20 minutes or less (practical level).
◯: Time until stickiness disappears exceeds 20 minutes and is 60 minutes or less (practical level).
X: Stickiness remains even after 60 minutes (unsuitable for practical use).

(Tactile evaluation)
About the coating film of Example 19-Example 22, the effect which raises the tactile sense by having mix | blended (C) nano silica was confirmed. In the evaluation method, the surface of the coating film was touched with a fingertip, and the touch was compared with Example 8. Moreover, the same evaluation was performed about the reference examples 1-8. The evaluation criteria are as follows. The evaluation results are shown in Table 3.
A: There is no stickiness or roughness as compared with Example 8, and it is smooth (practical level).
○: Equivalent to Example 8 (practical level).
X: More sticky or rough than in Example 8, and there is a feeling of resistance (unsuitable for practical use).

(Pencil hardness test)
A test was conducted in accordance with JIS K-5600-5-4: 1999 “Scratch hardness: pencil method”, and the hardness was evaluated based on the hardness of the hardest pencil with no scars. The evaluation results are shown in Table 4.

(Adhesion evaluation)
According to JIS K5600-5-6: 1999 “Cross Cut Method”, 100 1 mm × 1 mm grid-like cuts were made, and a peel test was performed using an adhesive tape. Evaluation criteria were also evaluated according to the same standard. The evaluation results are shown in Table 4.
○: 0 (practical level)
×: 1 to 5 (unsuitable for practical use)

(Moisture resistance evaluation)
In accordance with JIS K5600-5-6: 1999 “Cross cut method”, 100 1 mm × 1 mm grid-like cuts are put on the surface of the coating film, and the constant temperature and constant temperature is 50 ° C. and the atmospheric humidity is 95% RH. After leaving in a wet tank for 240 hours, a peel test with an adhesive tape was performed. Evaluation criteria were also evaluated according to the same standard. The evaluation results are shown in Table 4.
○: 0 (practical level)
×: 1 to 5 (unsuitable for practical use)

(Water resistance evaluation)
The base material on which the coating film was formed was immersed in warm water at 40 ° C. for 120 hours, then taken out from the warm water, wiped off with warm water on the surface, and the state of the coating film was visually confirmed. The evaluation criteria are as follows. The evaluation results are shown in Table 4.
○: No change (practical level).
Δ: Swelling was observed in the coating film (unsuitable for practical use).
X: The coating film was peeled off (unsuitable for practical use).

(Heat resistance evaluation)
In accordance with JIS K5600-5-6: 1999 “Cross cut method”, 100 grid-like cuts of 1 mm × 1 mm are put on the surface of the coating film, and a constant temperature bath with an atmospheric temperature of 80 ° C. and an atmospheric humidity of 50% RH. After leaving still for 72 hours, a peel test with an adhesive tape was performed. Evaluation criteria were also evaluated according to the same standard. The evaluation results are shown in Table 4.
○: 0 (practical level)
×: 1 to 5 (unsuitable for practical use)

(Acid resistance evaluation)
The base material on which the coating film was formed was immersed in 0.1 N sulfuric acid at 25 ° C. for 24 hours, and then taken out. The sulfuric acid on the surface was wiped off, and the state of the coating film was visually confirmed. The evaluation criteria are as follows. The evaluation results are shown in Table 4.
○: No change (practical level).
Δ: Swelling was observed in the coating film (unsuitable for practical use).
X: The coating film was peeled off (unsuitable for practical use).

(Alkali resistance evaluation)
The substrate on which the coating film was formed was immersed in a 0.1N sodium hydroxide aqueous solution at 55 ° C. for 24 hours, then taken out, wiped off the surface sodium hydroxide aqueous solution, and the state of the coating film was visually confirmed. The evaluation criteria are as follows. The evaluation results are shown in Table 4.
○: No change (practical level).
Δ: Swelling was observed in the coating film (unsuitable for practical use).
X: The coating film was peeled off (unsuitable for practical use).

(Evaluation of alcohol resistance)
Alcohol resistance was evaluated using a flat abrasion tester (manufactured by Toyo Seiki Co., Ltd.). The evaluation condition was to soak absorbent cotton in 99.5% ethanol and visually check the state of the coating film after 20 reciprocating rubs at 9.8 N on the coating film. The evaluation criteria are as follows. The evaluation results are shown in Table 4.
A: No change (practical level).
○: Slightly changed (practical lower limit level).
(Triangle | delta): The coating film of the area of less than 50% peeled, and the base material was visible (practical use improper).
X: The coating film with an area of 50% or more peeled off, and the substrate was visible (unsuitable for practical use).

(Evaluation of weather resistance)
Using a sunshine weather meter tester (model S80B, manufactured by Suga Test Instruments Co., Ltd.), the surface of the coating film was irradiated for 200 hours at 78.5 W / m ² using SWOM as a light source. confirmed. The evaluation criteria are as follows. The evaluation results are shown in Table 4.
○: No cracking or peeling and discoloration (practical level).
X: Cracking or peeling of the coating film was observed (unsuitable for practical use).

  The self-restoring coating films of Examples 1 to 22 were all highly transparent and excellent in gloss and drying properties. Furthermore, the restoration rate was high, and even if scratches were made, the scratches were easy to return. Further, it was confirmed that the coating film was not cracked or peeled off even when used for a long time.

  Examples 8 to 18 are examples for confirming the effect of drying property and the effect of improving self-restoration by blending (D) acrylic resin. Examples 8 to 18 were all excellent in drying properties. For example, Example 9 is an example in which (D) an acrylic resin was further blended on the basis of Example 3, and Example 9 was superior to Example 3 in drying property. In Example 8, the surface hardness of the coating film was large and the self-restoring property was excellent. About Example 10- Example 13, restoration rate rises rather than Example 4-7 which is a corresponding example, and the effect of the self-restoration improvement by having mix | blended (D) acrylic resin can be confirmed. It was. For example, Example 11 is an example in which (D) an acrylic resin is further blended on the basis of Example 5, but the restoration rate of Example 5 is 29.7%, while that of Example 11 is The restoration rate was 65.3%, confirming a significant improvement in self-restoration. On the other hand, in Examples 14 to 18, since the blending amount of (D) acrylic resin was large, the effect of improving self-restoration was smaller than that of Example 8 and Examples 10 to 13.

  Examples 19 to 22 are examples for confirming the effect of improving the tactile sensation of the coating film by blending (C) nanosilica, and all are based on Example 8 and further include (C) nanosilica. It is blended. In all of Examples 19 to 22, the tactile sensation was improved as compared with Example 8. Moreover, irrespective of the compounding amount of (C) nanosilica, there was no adverse effect on the surface hardness and the restoration rate of the coating film due to the blending of (C) nanosilica, and both retained high self-restorability.

  Since Comparative Example 1 contained only (A) a lactone-modified acrylic resin and no (B) polycarbonate diol, the amount of increase in haze value after the Taber abrasion test (ΔH) was large, and the coating film was scratched. It was. Since the comparative example 2 contained only (B) polycarbonate diol and did not contain (A) lactone modification | denaturation acrylic resin, the physical strength of the coating film was not obtained and it did not become a coating film.

  Reference Examples 1 to 8 are reference examples in which other particles were blended in place of (C) nano silica. In Reference Example 1 and Reference Example 2 in which alumina was blended as other particles, the amount of increase in the haze value (ΔH) after the Taber abrasion test was large and scratched. In Reference Example 3 and Reference Example 4 in which silica was blended as the other particles, the average particle size was large, so that the texture was felt and the tactile sensation was inferior. Further, in Reference Example 4, the haze value increase (ΔH) after the Taber abrasion test was large and scratched. In Reference Example 5 and Reference Example 6 in which zinc oxide was blended as other particles, the transparency was poor before the Taber abrasion test, and the increase in the haze value (ΔH) after the Taber abrasion test was large and scratched. . In Reference Example 7 in which silicate was blended as other particles, the increase in haze value (ΔH) after the Taber abrasion test was large and scratched. In Reference Example 8 in which polyethylene was blended as other particles, the transparency was poor before the Taber abrasion test, and the increase in haze value (ΔH) after the Taber abrasion test was large and scratched.

  The self-restoring coating film plastic material according to the present invention provides high gloss, high transparency, does not cause cracking or peeling of the coating film even when used for a long time, and forms a coating film that does not easily leave scratches. It is suitable as a coating composition for protecting the surfaces of mobile devices such as mobile phones and personal computers, automobile bodies, and exterior parts.

Claims (5)

  A self-recovering coating composition comprising (A) a lactone-modified acrylic resin and (B) a polycarbonate diol.   The self-restoring coating composition according to claim 1, further comprising (D) an acrylic resin. Furthermore, (D) containing an acrylic resin,
The ratio (A / (A + B)) of the dry mass of (A) lactone-modified acrylic resin to the total dry mass (A + B) of (A) lactone-modified acrylic resin and (B) polycarbonate diol is 27/100 or more and 60/100. The self-restoring coating composition according to claim 1, wherein   Furthermore, (C) nano silica is contained, The self-restoring coating composition as described in any one of Claims 1-3 characterized by the above-mentioned.   A self-restoring coating film comprising the self-restoring coating composition according to any one of claims 1 to 4 and a polyisocyanate compound.