JP7689446B2 - Thermosetting coating composition, coating film and laminate using same - Google Patents

Description

The present invention relates to a thermosetting coating composition, a coating film and a laminate using the same.

Patent Document 1 discloses a two-liquid polyurethane coating composition, which relates to an invention that aims to provide a coating film with a matte effect, a smooth feel, a moist feel, and high designability. This two-liquid polyurethane coating composition contains a base agent containing a polycarbonate-based polyol having an average molecular weight of 1000 to 2000, a curing agent containing polyisocyanate, silica, a surface conditioner, and a catalyst. It is disclosed that the silica filler in this coating composition is a powdery granular material that imparts a smooth feel to the touch and has an average particle size of 50 μm or less. The content of the silica filler is 0.5 to 15 wt % based on the solid content of the coating composition. It is also disclosed that the surface conditioner in this coating composition is intended to impart a moist, high tactile feel to the coating film. A specific example of the surface conditioner is polyether silicone. It is disclosed that the content of the surface conditioner is 0.5 to 2.0 wt % based on the solid content of the coating composition.

Patent Document 2 discloses a coating composition, which is an invention aimed at improving the resistance to sunscreens while maintaining a good tactile feel of a coating film formed by the coating composition. The coating composition contains a base resin selected from the group consisting of acrylic resins, polyester resins, polyether resins, and polycarbonate resins, which have a solubility parameter of less than 20 MPa ^1/2 , a number average molecular weight of 500 to 20,000, and a hydroxyl value of 50 to 200 mgKOH/g, and a polyisocyanate resin, which has a solubility parameter of less than 20 MPa ^1/2 and has two or more isocyanate groups at its terminals, in a weight ratio of 65 parts by weight:35 parts by weight to 88 parts by weight:12 parts by weight (the sum of the two is 100 parts by weight). It is disclosed that the coating composition may contain additional components such as a tactile agent and a matting agent. An example of the tactile agent is a urethane resin powder. An example of the matting agent is silica fine particles.

JP 2015-218289 A JP 2014-65796 A

Coating compositions such as the coating film compositions and paint compositions described in Patent Documents 1 and 2 could not form a coating film that had both abrasion resistance, chemical resistance, and a good feel. In particular, they could not fully achieve the good feel of nubuck, which has excellent smoothness and moistness. Furthermore, they could not maintain this good feel for a long period of time.

The general technical problems of coating compositions, coating films, and laminates including coating films include the following. In conventional coating compositions that mainly use inorganic particles such as silica particles to provide a tactile sensation, the physical properties of the coating film obtained from these, such as abrasion resistance, are good. However, this coating film may become hard and not develop a moist feeling, resulting in a dry feel. A matte coating film formed by a coating composition using low Tg polyurethane resin beads has a moist feeling, but the coating film surface may become uneven and may lack smoothness. In addition, sufficient abrasion resistance may not be achieved. In order to enhance the smoothness and moist feeling, a thick film thickness of, for example, 20 μm or more is required, which may increase costs and reduce manufacturability. Since the surface orientation in the coating film changes depending on the additives to be mixed, if the solubility in the binder resin is not specified, a sufficient tactile sensation may not be obtained. In addition, if the film does not have a reactive group, changes over time may occur and the desired tactile sensation may not be sustained. Lacquer paints and mildly reactive paints, which dry quickly, are less resistant to abrasion and chemicals.

Thus, in the past, it was not sufficient to obtain the smooth, moist, and pleasant tactile feel of nubuck in addition to the physical properties and functions of typical coating films, such as drying, abrasion resistance, solvent resistance, and chemical resistance. Therefore, it is desired to provide a coating composition, coating film, and laminate that can achieve the smooth, moist, and pleasant tactile feel of nubuck in addition to the physical properties and functions of typical coating films, such as drying, abrasion resistance, solvent resistance, and chemical resistance.

The present invention was made in consideration of the above circumstances, and its purpose is to provide a thermosetting coating composition, coating film, and laminate that can achieve a nubuck-like, smooth, moist feel over a long period of time in addition to the general physical properties of coating films, such as abrasion resistance and chemical resistance.

The thermosetting coating composition according to the present invention is a thermosetting coating composition comprising a hydroxy group-containing resin (A), silica particles (B), a polyisocyanate (C) and a hydroxy group-containing surface conditioner (D),
The hydroxyl group-containing surface conditioner (D) contains at least one selected from the group consisting of a silicone skeleton and a fluororesin skeleton,
When the SP values of the hydroxyl group-containing resin (A), the polyisocyanate (C) and the hydroxyl group-containing surface conditioner (D) are SP(A), SP(C) and SP(D), respectively, the following formulas (1) and (2):
1.0≦SP(A)-SP(D)≦2.5 (1)
1.0≦SP(C)-SP(D)≦2.5 (2)
Fulfilling
The silica particles (B) have a volume-based 50% particle size R of 0.1 μm or more and 5 μm or less. The SP value will be described later.

The thermosetting coating composition according to the present invention further comprises:
The silica particles (B) may be hydrophilic silica particles.

The thermosetting coating composition according to the present invention further comprises:
The mass of the hydroxy group-containing surface conditioner (D) may be 0.5% or more and 5.0% or less of the total solid content mass of the hydroxy group-containing resin (A) and the polyisocyanate (C).

The thermosetting coating composition according to the present invention further comprises:
The hydroxy group-containing resin (A) may have an OH value of 10 mgKOH/g or more and 200 mgKOH/g or less.

The coating film according to the present invention is
The above-mentioned thermosetting coating composition is used.

The coating film according to the present invention is
A ratio (R/T) of the 50% particle diameter R of the silica particles (B) to a thickness T of the coating film may be 0.02 or more and 0.5 or less.

The laminate according to the present invention is
A polymer resin substrate;
and the above coating disposed on the polymeric resin substrate.

It is possible to provide a thermosetting coating composition, coating film and laminate that can achieve a nubuck-like, pleasant feel with excellent smoothness and moistness.

FIG. 2 is an explanatory diagram of a coating film and a laminate structure including the coating film according to the present embodiment. FIG. 2 is an explanatory diagram of the structure of a coating film with respect to the tactile feel of the coating film. 1 is an enlarged photograph (2000 times) of the coating surface of Example 7. 1 is an enlarged photograph (400x) of the coating surface of Example 7. 1 is an enlarged photograph (2000 times) of the coating surface of Comparative Example 1. 1 is an enlarged photograph (2000 times) of the coating surface of Comparative Example 5.

The thermosetting coating composition, coating film, and laminate according to an embodiment of the present invention will be described with reference to the drawings.

(Summary)
1 shows a laminate 100 according to this embodiment. The laminate 100 includes a polymer resin substrate 9 and a coating film 1 according to this embodiment disposed on the polymer resin substrate 9. The coating film 1 is formed, for example, by applying a thermosetting coating composition according to this embodiment (hereinafter, referred to as a coating agent) to the polymer resin substrate 9 and then thermally curing the composition. The coating film 1 provides a nubuck-like pleasant feel that is excellent in smoothness and moistness.

The coating film 1 may be used, for example, in the interior of a vehicle. In this case, the polymer resin substrate 9 may be a wall or frame of the interior of the vehicle, a console, a dashboard, a door trim, etc. Examples of the types of substrate resin that the polymer resin substrate 9 may contain include polyvinyl chloride, polyolefin elastomer, polyurethane, PET, etc.

The coating agent contains a hydroxyl group-containing resin (A), silica particles (B), a polyisocyanate (C) and a hydroxyl group-containing surface conditioner (D).

The hydroxyl group-containing surface conditioner (D) (hereinafter sometimes referred to as surface conditioner D) contains one or more selected from the group consisting of a silicone skeleton and a fluororesin skeleton.

When the SP values of the hydroxyl group-containing resin (A), the polyisocyanate (C) and the hydroxyl group-containing surface conditioner (D) are SP(A), SP(C) and SP(D), respectively, the following formulas (1) and (2):
1.0≦SP(A)-SP(D)≦2.5 (1)
1.0≦SP(C)-SP(D)≦2.5 (2)
Meet the following.

The 50% volumetric particle size R of the silica particles (B) is 0.1 μm or more and 5 μm or less. The 50% volumetric particle size R is the median size of the volumetric particle size distribution measured by a laser diffraction scattering method using a Microtrack particle size distribution measuring device (MT3300, manufactured by Nikkiso Co., Ltd.).

(Detailed explanation)
As shown in Fig. 1, the coating film 1 comprises a binder resin 2 containing a reaction product of a hydroxyl group-containing resin (A) and a polyisocyanate (C), silica particles B dispersed in the binder resin 2, and a surface conditioner D disposed on the surface of the coating film 1. As described above, the coating film 1 is formed by applying a coating agent containing a hydroxyl group-containing resin (A), silica particles (B), polyisocyanate (C), and a hydroxyl group-containing surface conditioner (D) to a substrate (in this embodiment, as an example, a polymer resin substrate 9) and then thermally curing the coating agent. The coating agent will be described later.

The coating film 1 has the following structure, thereby realizing the desired good tactile feel. That is, the surface conditioner D spreads over the entire surface of the coating film 1 (the surface opposite to the surface facing the polymer resin substrate 9) and is arranged so as to cover the binder resin 2. The silica particles B are segregated near the surface of the coating film 1 and dispersed in the coating film 1. Some of the silica particles B are exposed and protrude from the surface of the coating film 1 with a part of the particle embedded in the binder resin 2. In addition, the silica particles B and the surface conditioner D are uniformly dispersed on the surface of the coating film 1 due to the formulation of the coating agent described later. In the coating film 1, the structure in which the binder resin 2, the silica particles B, and the surface conditioner D are positioned in such a way (hereinafter simply referred to as the structure of the coating film 1) realizes a nubuck-like good tactile feel with excellent smoothness and moistness.

The good tactile sensation will now be described in more detail. As shown in FIG. 2, when a person's skin H (e.g., a finger) touches the coating film 1 in a pressing manner, the skin H comes into contact with the protruding silica particles B. When the skin H is pressed against the silica particles B, they sink due to the elasticity of the binder resin 2. The sinking of the silica particles B creates a moist sensation.

When skin H touches the surface of coating film 1 in a tracing manner, the fine, continuous protrusions of silica particles B continuously and weakly stimulate skin H, giving a feeling of smoothness. After contacting silica particles B, skin H also comes into contact with surface conditioner D. At this time, the low surface tension generated by surface conditioner D ensures that moisture and oil on the skin are not taken away by coating film 1 and are retained. This gives a feeling of moisturization.

In this way, the silica particles B and surface conditioner D are uniformly dispersed on the surface of the coating film 1, providing a sufficient feeling of both smoothness and moisture, and achieving an excellent nubuck-like feel.

As shown in FIG. 1, in coating film 1, the ratio (R/T) of the 50% particle diameter R of silica particles B to the film thickness T of coating film 1 is preferably 0.02 or more and 0.5 or less. More preferably, it is 0.05 or more and 0.3 or less. This provides an appropriate smooth feel. The preferred range of film thickness T is 7 μm or more and 50 μm or less. More preferably, it is 10 μm or more and 25 μm or less. Details of the 50% particle diameter R of silica particles B will be described later.

The structure of the coating film 1 described above is realized by the formulation of the coating agent described above. In addition to the hydroxyl group-containing resin (A), silica particles (B), polyisocyanate (C) and hydroxyl group-containing surface conditioner (D), the coating agent may contain components generally formulated as coating agents, i.e., catalysts, pigments, fillers other than silica particles (B) (e.g., resin particles such as acrylic resin particles, urethane resin particles, phenolic resin particles and epoxy resin particles), antibacterial agents, antiviral agents, additives for imparting other functionality, and solvents. Examples of antibacterial or antiviral agents include particles of silver supported on titanium oxide, particles of silver supported on silica or alumina, particles of double metal (silver, zinc and copper) ions supported on glass, copper iodide particles, titanium oxide particles, zinc oxide particles, quaternary ammonium salts and copper ion-supported acrylic resins.

Commercially available antibacterial or antiviral agents may be used. Commercially available titanium oxide particles carrying silver include, for example, ATOMY BALL-(S) manufactured by JGC Catalysts and Chemicals. Silica-alumina particles carrying silver include, for example, ATOMY BALL-(UA), ELCOM NU-1023SIV, and ELCOM NU-1024SIV, also manufactured by JGC Catalysts and Chemicals. Silica particles carrying silver include, for example, IONPURE ZAF HS manufactured by Ishizuka Glass. Co., Ltd. Co., Ltd. Copper iodide particles include, for example, Cufitec BE4-ANA01, AA1-ANA01, BB2-ANA01, and BD3-ANA01 manufactured by NBC Meshtec.

The hydroxyl group-containing resin (A) reacts with the polyisocyanate (C) to become a binder resin that forms the coating film 1.

A wide variety of known polyols can be used as the hydroxyl group-containing resin (A). As the hydroxyl group-containing resin (A), a polyether polyol, a polyester polyol, a polycarbonate polyol, a diol, a copolymer thereof, a polyol, or a mixture thereof can be suitably used. As the hydroxyl group-containing resin (A), a polycarbonate diol obtained by converting glycol into a carbonate ester is preferred. The number average molecular weight of the hydroxyl group-containing resin (A) is preferably 1000 or more and 2000 or less. The hydroxyl group-containing resin (A) may be modified by a resin such as silicone modification, fluorine modification, fatty acid modification, or urethane modification.

The OH value of the hydroxyl group-containing resin (A) is preferably 10 mgKOH/g or more and 200 mgKOH/g or less. The OH value of the hydroxyl group-containing resin (A) is more preferably 50 mgKOH/g or more and 110 mgKOH/g or less. The magnitude of the OH value of the hydroxyl group-containing resin (A) is related to the ease of the crosslinking reaction with the polyisocyanate (C) described later. In other words, it affects the mechanical strength and tactile feel of the coating film 1. By having the OH value of the hydroxyl group-containing resin (A) be 10 mgKOH/g or more, a sufficient number of crosslinks can be formed with the polyisocyanate (C), thereby ensuring abrasion resistance as mechanical strength. By having the OH value be 200 mgKOH/g or less, the formation of an excessive number of crosslinks can be prevented, and the mechanical strength is not too high, and a soft tactile feel that feels smooth, etc. can be achieved. Here, the OH value is calculated by acetylating the hydroxyl group-containing resin (A) with acetic anhydride, quantifying the free acetic acid with potassium hydroxide, and expressing it as the amount of potassium hydroxide (mg) equivalent to the hydroxyl groups contained in 1 g of the hydroxyl group-containing resin (A).

The SP value (SP(A)) of the hydroxyl group-containing resin (A) is preferably 9.5 or more and 12.5 or less. The SP value of the hydroxyl group-containing resin (A) is more preferably 10 or more and 11 or less. When the SP value of the hydroxyl group-containing resin (A) is within a predetermined range, the difference in SP value with the surface conditioner (D) becomes a preferable value, making it easier to realize a structure in which the silica particles B and the surface conditioner D are uniformly dispersed on the surface of the coating film 1, and making it easier to obtain a moist feel.

The glass transition temperature (Tg) of the hydroxyl group-containing resin (A) is preferably less than 25°C. The glass transition temperature of the hydroxyl group-containing resin (A) is more preferably less than 0°C. When the glass transition temperature of the hydroxyl group-containing resin (A) is within the specified range, a moist feel is easily obtained.

Polyisocyanate (C) is a compound having two or more isocyanate groups in one molecule, and is a so-called polyisocyanate resin. Polyisocyanate (C) is a curing agent for thermally curing (crosslinking) hydroxyl group-containing resin (A). Note that the binder resin 2 in the coating film 1 of this embodiment is a hydroxyl group-containing resin (A) thermally cured by polyisocyanate (C).

The number of isocyanate groups in polyisocyanate (C) is preferably in the range of 3 to 5. The number of isocyanate groups contained in polyisocyanate (C) is important for the formation of a three-dimensional crosslinked structure in coating film 1. In other words, by using polyisocyanate (C) having 3 or more isocyanate groups, the crosslinking density becomes sufficient and the performance such as scratch resistance becomes good. By using polyisocyanate (C) having 5 or less isocyanate groups, the coating film has a moderate hardness and a good feel.

The polyisocyanate (C) is preferably a blocked isocyanate in which the isocyanate group is protected with a blocking agent such as an oxime-based, alcohol-based, cellosolve-based, pyrazole-based, or active methylene-based blocking agent. This ensures the storage stability of the coating agent before use in painting (forming the coating film 1), while allowing the blocking agent to be dissociated by heat treatment (heating) after application of the coating agent, thereby allowing thermal curing to proceed. From the viewpoint of the heat resistance of the substrate film, the blocking agent is preferably active methylene. In addition, a catalyst may be used as necessary to promote thermal curing by the polyisocyanate (C). As a catalyst for promoting thermal curing, an amine-based catalyst, a tin-based catalyst, or the like may be used.

Specific examples of polyisocyanate (C) are listed below. The polyisocyanate (C) may be used alone or in combination of two or more of the following: For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, Examples of the diisocyanates include aromatic diisocyanates such as polyphenylene polymethylene polyisocyanate and crude tolylene diisocyanate, aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate, and lysine diisocyanate, organic diisocyanates such as isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and alicyclic diisocyanates such as tetramethyl xylene diisocyanate, and biuret modified products, uretdione modified products, carbodiimide modified products, isocyanurate modified products, uretonimine modified products, and mixed modified products thereof of the organic polyisocyanates. In particular, active methylene block isocyanurate modified hexamethylene isocyanate is preferred from the viewpoints of touch, pot life, curability, and low yellowing.

By forming a coating film using such polyisocyanate (C), urethane bonds, and in some cases ester bonds, amide bonds, and urea bonds are formed with the above-mentioned hydroxyl group-containing resin (A), thereby achieving sufficient mechanical strength. In addition, by combining it with silica particles (R) described below, a good smooth feel can be achieved.

The SP value (SP(C)) of polyisocyanate (C) is preferably 9.5 or more and 12.5 or less. The SP value of polyisocyanate (C) is more preferably 10 or more and 11 or less. When the SP value of polyisocyanate (C) is within a predetermined range, the difference in SP value with surface conditioner D becomes a preferable value, making it easier to realize a structure in which silica particles B and surface conditioner D are uniformly dispersed on the surface of coating film 1, and making it easier to obtain a smooth and moist feel.

The silica particles (B) are an additive and filler that give the coating film 1 a matte design and a nubuck-like feel.

The average particle diameter of the silica particles (B), for example, the 50% particle diameter R on a volume basis (hereinafter sometimes simply referred to as particle diameter R), is 0.1 μm or more and 5 μm or less, as described above. The particle diameter R is preferably 1.0 μm or more and 4.5 μm or less, and more preferably 1.5 μm or more and 3.0 μm or less. By setting the particle diameter R in this manner, it is possible to impart a moderate matte feel and smooth feel, and to realize a comfortable nubuck-like feel in the coating film 1.

The silica particles (B) are preferably hydrophilic silica particles. In other words, the silica particles are preferably not subjected to a hydrophobic surface treatment. In more detail, "hydrophilic" means that the surface is the surface of the silica particle itself or the surface of another inorganic substance, and it is sufficient that the surface has not been treated with a treatment agent such as a silane coupling agent or an organic titanate to make it lipophilic (hydrophobic).

In the coating agent according to this embodiment, the pigment volume concentration (PVC) of the silica particles (B) is preferably 4.6% to 13.7%. The pigment volume concentration (PVC) is a value calculated from the volume (L) of the silica particles (B) and the total solid volume (M) of the hydroxyl group-containing resin (A) and polyisocyanate (C) according to the formula: L/(L+M)×100.

Silica particles B may be particles synthesized by either a dry method or a wet method. In this embodiment, wet silica particles (B) are preferred. This is because silica particles (B) synthesized by a wet method have more surface silanol groups than particles synthesized by a dry method, and therefore exhibit hydrophilicity suitable for this embodiment.

Examples of dry methods include the combustion method and the arc method.

The wet method may be either a sol-gel method or a precipitation method, but in this embodiment, silica particles (B) synthesized by a wet method are particularly suitable.

An example of silica particles (B) produced by the sol-gel method is colloidal silica, which is obtained by replacing the water in silica hydrogel with a solvent that has a boiling point of 70°C or less and is miscible with water (e.g., methanol, acetone, methyl formate, methyl acetate), and then removing the solvent by heating.

An example of silica particles (B) produced by the precipitation method is precipitated silica (silica particles obtained by agglomeration by dropping sodium ions such as sodium chloride or sodium sulfate into an aqueous solution of sodium silicate).

In addition, examples of silica particles (B) produced by the dry method include fumed silica (colloidal silica consisting of silica soot produced by burning silicon tetrachloride).

Surface conditioner D (hydroxy group-containing surface conditioner (D)) is an additive that imparts a suitable gloss to the surface of coating film 1, and also imparts a moist feel to the surface, abrasion resistance, and chemical resistance.

In the coating agent according to this embodiment, the mass of the surface conditioner D is preferably formulated to be 0.5% to 5.0% (0.5 phr to 5.0 phr) of the total solid mass of the hydroxyl group-containing resin (A) and the polyisocyanate (C). Hereinafter, the ratio of the mass of the surface conditioner D to the total solid mass of the hydroxyl group-containing resin (A) and the polyisocyanate (C) may be simply referred to as the weight ratio (D). By setting the weight ratio (D) at such a level, a moist feel can be achieved in the coating film 1. The weight ratio (D) is preferably 1.0% to 4.0%. This allows a more comfortable moist feel (for example, a moist feel that is compatible with a smooth feel) to be achieved.

Surface conditioner D contains at least one selected from the group consisting of polymer compounds having hydroxyl groups and a silicone skeleton (hereinafter simply referred to as silicone-based additives) and polymer compounds having hydroxyl groups and a fluororesin skeleton (hereinafter referred to as fluorine-based additives).

Surface conditioner D may be a silicone-based additive or a fluorine-based additive, or both may be added and mixed at the same time.

As the silicone-based additive, one having a polysiloxane structure is preferably used. As the hydroxyl group-containing polysiloxane-based surface conditioner, one containing a polysiloxane polyether copolymer, an alkyl-modified polysiloxane, etc. in its structure can be used.

The silicone additive should have an OH value based on the non-volatile content of 10 mgKOH/g or more and 80 mgKOH/g or less. The silicone additive has a hydroxyl group (OH group) and can form a urethane bond with the polyisocyanate (C), and in some cases an ester bond, an amide bond, or a urea bond. This allows the silicone additive to be fixed to the surface of the coating film 1, and the coating film 1 can maintain its good tactile feel, such as its smooth feel, for a long period of time.

As the hydroxyl group-containing fluorine-based additive, a monomer containing a polyfluoroalkyl group or a monomer containing a polyfluoroether group, or a homopolymer or copolymer of both of these, can be suitably used, and preferably a nonionic additive is used.

The OH value of fluorine-based additives is the same as that of silicone-based additives.

The SP value of surface conditioner D (SP(D)) is preferably 8 or more and 10 or less. The SP value of surface conditioner D is more preferably 8.5 or more and 9.5 or less. When the SP value of surface conditioner D is within a predetermined range, the difference in SP value between the hydroxy group-containing resin (A) and the polyisocyanate (C) becomes a preferable value, which makes it easier to realize a structure in which the silica particles B and the surface conditioner D are uniformly dispersed on the surface of the coating film 1, and makes it easier to obtain a moist feel.

As described above, SP(A), SP(C) and SP(D) satisfy the above formulas (1) and (2). SP(A), SP(C) and SP(D) more preferably satisfy the following formulas (3) and (4):
1.6≦SP(A)-SP(D)≦2.3 (3)
1.6≦SP(C)-SP(D)≦2.3 (4)
It is preferable that the following is satisfied.

When SP(A), SP(C) and SP(D) satisfy formulas (1) and (2), the structure of the coating film 1 described above is properly realized. This allows a nubuck-like texture with excellent smoothness and moistness to be achieved. When SP(A), SP(C) and SP(D) further satisfy formulas (3) and (4), the nubuck-like texture with excellent smoothness and moistness is further improved.

The SP value (solubility parameter) and the method for measuring the SP value in this embodiment will be described. The SP value is a physical property value defined as the square root of the cohesive energy density. The SP value is a parameter of the affinity of a substance, and two components with a small difference in SP value are a guide to determine characteristics such as ease of mixing and affinity.

The SP value can be calculated by the following method. 0.5 g of the sample to be measured for the SP value is weighed into a 100 mL Erlenmeyer flask, and 10 mL of acetone is added to dissolve the resin. Next, hexane is added dropwise while stirring with a magnetic stirrer. The amount of hexane added (vh) at the point where the solution becomes cloudy (cloudy point) is calculated as the hexane is added. Next, the amount of deionized water added (vd) at the cloudy point is calculated when deionized water is used instead of hexane. From vh and vd, the SP value can be calculated using the formula given in the reference: SUH, CLARKE, J. P. S. A-1, 5, 1671-1681 (1967).

The method of applying the coating agent according to this embodiment is not particularly limited and may be any method commonly used by those skilled in the art. Examples of application methods include dip coating, air knife coating, curtain coating, roller coating, spray coating, bar coating (e.g., wire bar coating), die coating, inkjet coating, gravure coating, and extrusion coating (U.S. Patent No. 2,681,294).

Below, we will explain examples of the coating agent of this embodiment, as well as the coating film and laminate formed using this coating agent.

In the examples described below, resins 1 to 3 produced in Production Examples 1 to 3 below were used.

(Production Example 1)
382g of 1,5-pentanediol, 433g of 1,6-hexanediol, and 650g of ethylene carbonate were charged into a 2L separable flask equipped with a stirrer, a thermometer, and a vacuum jacketed Oldershaw flask with a reflux head on top, and after stirring and dissolving at 70°C, 0.015g of lead acetate trihydrate was added as a catalyst. The flask was heated in an oil bath set at 175°C, and the reaction was carried out for 12 hours at an internal temperature of 140°C, a vacuum degree of 1.0kPa to 1.5kPa, and a part of the distillate was removed from the reflux head at a reflux ratio of 4. The Oldershaw was then replaced with a simple distillation apparatus, the oil bath setting was raised to 185°C, and the reaction was carried out for another 2.5 hours at an internal temperature of 160°C to 165°C while removing the diol produced. This reaction produced a viscous liquid reactant at room temperature. The OH value of the reaction product obtained was 110 mgKOH/g (number average molecular weight 1000), and the solid content (non-volatile content) was 100%. The SP value of the reaction product obtained was 10.6. The reaction product obtained in this Production Example 1 is hereinafter referred to as Resin 1.

(Production Example 2)
In Production Example 1, the synthesis was carried out in the same manner, except that the Oldershaw was replaced with a simple distillation apparatus, the oil bath was set to 185°C, the internal temperature of the flask was 160°C to 165°C, and the time for removing the diol produced was 4 hours. This reaction produced a viscous liquid reactant at room temperature. The OH value of the reactant obtained was 56 mgKOH/g (number average molecular weight 2000), and the solid content (non-volatile content) was 100%. The SP value of the reactant obtained was 10.1. The reactant obtained in Production Example 2 is hereinafter referred to as Resin 2.

(Production Example 3)
In Production Example 1, the Oldershaw was replaced with a simple distillation apparatus, and the oil bath was set to 185°C, and the time for removing the diol produced was set to 1.5 hours at an internal temperature of 160°C to 165°C. The reaction yielded a viscous liquid reactant at room temperature. The OH value of the reactant obtained was 225 mgKOH/g (number average molecular weight 500), and the solid content (non-volatile content) was 100%. The SP value of the reactant obtained was 11.0. The reactant obtained in Production Example 3 is hereinafter referred to as Resin 3.

The coating agent, coating film, and laminate (hereinafter referred to as the coating film, etc.) of Example 1 were prepared as follows.

100.0 g of resin 1 was weighed as the hydroxyl group-containing resin (A), 127.3 g of butyl acetate as the solvent, 24.3 g of silica particles (B) with a particle size R of 1.5 μm and not subjected to hydrophobic surface treatment (Nipsil E-220A, manufactured by Tosoh Corporation), and 3.0 g of polydimethylsiloxane (TEGO PROTECT 5000N, manufactured by Evonik Japan Co., Ltd.), a silicone additive with an SP value of 8.6 and an OH value of 48 mgKOH/g, as the surface conditioner D, and mixed and stirred with a disperser. Then, 63.7 g of ethyl acetate was added as the solvent and further stirred to obtain a base liquid with a solid content of 40%.

Separate from the base liquid, 45.3 g of HDI polyisocyanate (Sumidur N3300, manufactured by Sumika Covestro Urethane Co., Ltd.) with 100% solids (non-volatile content) was weighed as polyisocyanate (C), and 211.9 g of ethyl acetate was weighed as a solvent, and these were mixed to obtain a hardener liquid. Furthermore, the base liquid and hardener liquid were stirred using a disper to obtain a coating agent with a solids content of 30%. The weight ratio (D) of this coating agent was 2.04%.

Using a bar coater #32, the mixture was coated (painted) onto a PET film (Lumirror U40, manufactured by Toray Industries, Inc.) as a polymer resin substrate, and then dried and thermally cured at 120°C for 5 minutes. This resulted in a film with a coating as a laminate. The thickness of this coating was 10 μm. The ratio (R/T) of the particle diameter R of the silica particles B to the thickness T of the coating 1 was 0.15.

In Example 2, a coating film and the like were obtained in the same manner as in Example 1, except that silica particles (B) with a particle diameter R of 3.0 μm and without hydrophobic surface treatment (Nipsil E-200A, manufactured by Tosoh Corporation) were used. The weight ratio (D) in this coating agent was 2.04%. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the film thickness T of coating film 1 was 0.30.

In Example 3, the formulation amount of silica particles (B) was changed to 36.5 g, and the amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%, but other than that, a coating film and the like were obtained in the same manner as in Example 1. The weight ratio (D) in this coating agent was 2.04%. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the film thickness T of coating film 1 was 0.15.

In Example 4, the formulation amount of silica particles (B) was changed to 12.2 g, and the amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%, but other than that, a coating film and the like were obtained in the same manner as in Example 1. The weight ratio (D) in this coating agent was 2.04%. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Example 5, the formulation amount of surface conditioner D was changed to 5.9 g, and the amount of solvent was adjusted so that the solids concentration of the coating agent was 30%. In this coating agent, the weight ratio (D) was 4.09%. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Example 6, the coating film was obtained in the same manner as in Example 1, except that the amount of surface conditioner D was changed to 1.5 g and the amount of solvent was adjusted so that the solids concentration of the coating agent was 30%. The weight ratio (D) of this coating agent was 1.02%. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Example 7, 152.0 g of HDI-based blocked polyisocyanate (MF-K60B, manufactured by Asahi Kasei Corporation) with a solid content (non-volatile content) of 60% was used as polyisocyanate (C), the formulation amount of surface conditioner D was changed to 3.9 g, the blended amount of silica was changed to 32.0 g, and the amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%. Except for this, a coating film was obtained in the same manner as in Example 1. The weight ratio (D) in this coating agent was 2.04%. The ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Example 8, 152.0 g of HDI-based blocked polyisocyanate with a solid content (non-volatile content) of 60% was used as polyisocyanate (C), the formulation amount of silica particles (B) was changed to 32.0 g, and further, surface conditioner D was changed to 3.9 g of a fluorine additive containing an OH group with an SP value of 9.6 (Megafac F-556, manufactured by DIC Corporation), and the amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%. A coating film was obtained in the same manner as in Example 1. The weight ratio (D) in this coating agent was 2.04%. The ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Example 9, resin 2 was used as the hydroxyl group-containing resin (A), the amount of polyisocyanate (C) was changed to 23.1 g, the amount of silica particles (B) was changed to 20.6 g, and the amount of surface conditioner D was changed to 2.5 g. The amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%. Except for this, a coating film was obtained in the same manner as in Example 1. The weight ratio (D) in this coating agent was 2.04%. The ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Example 10, resin 3 was used as the hydroxyl group-containing resin (A), the amount of polyisocyanate (C) was changed to 92.7 g, the amount of silica particles (B) was changed to 32.3 g, and the amount of surface conditioner D was changed to 3.9 g. A coating film was obtained in the same manner as in Example 1, except that the amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%. The weight ratio (D) in this coating agent was 2.04%. The ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

For comparison with the above examples, comparative coatings were created as follows:

In Comparative Example 1, the coating film was obtained in the same manner as in Example 1, except that silica particles (B) were not used and the amount of solvent was adjusted so that the solids concentration of the coating agent was 30%. The weight ratio (D) in this coating agent was 2.04%.

In Comparative Example 2, the coating film was obtained in the same manner as in Example 1, except that the surface conditioner D was not used and the amount of solvent was adjusted so that the solids concentration of the coating agent was 30%. The weight ratio (D) of this coating agent was zero%. In addition, the ratio (R/T) of the particle diameter R of the silica particles B to the film thickness T of the coating film 1 was 0.15.

In Comparative Example 3, instead of silica particles (B), 60.8 g (24.3 g in terms of solids) of a methanol dispersion of silica particles (MA-ST-L, manufactured by Nissan Chemical, solids concentration 40%) with a particle diameter R of 45 nm and not subjected to hydrophobic surface treatment was used as a filler, and a coating film etc. was obtained in the same manner as in Example 1, except that the amount of solvent was adjusted so that the solids concentration of the coating agent was 30%. The weight ratio (D) of this coating agent was 2.04%. The ratio (R/T) of the particle diameter R of the silica particles to the thickness T of the coating film 1 was 0.0045.

In Comparative Example 4, a coating film was obtained in the same manner as in Example 1, except that silica particles (B) were replaced with silica particles (ACEMATT HK400, manufactured by Evonik Japan Co., Ltd.) having a particle diameter R of 6 μm and not subjected to hydrophobic surface treatment as a filler. The weight ratio (D) of this coating agent was 2.04%. The ratio (R/T) of the particle diameter R of the silica particles to the thickness T of the coating film 1 was 0.60.

In Comparative Example 5, a coating film was obtained in the same manner as in Example 1, except that 13.3 g of urethane particles (Art Pearl C-1000T, manufactured by Negami Chemical Industries, Ltd.) having a particle size R of 3 μm were used as the filler instead of the silica particles (B). The weight ratio (D) in this coating agent was 2.04%. In addition, the ratio of the average particle size of the urethane particles to the thickness T of the coating film 1 was 0.30.

In Comparative Example 6, a coating film was obtained in the same manner as in Example 1, except that 3.0 g of a hydrophobic fluorine additive (Megafac F-552, manufactured by DIC Corporation) containing no OH groups and having an SP value of 9.2 was used as the surface conditioner instead of surface conditioner D. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Comparative Example 7, a coating film was obtained in the same manner as in Example 1, except that 3.0 g of a fluorine additive (Megafac F-563, manufactured by DIC Corporation) containing an OH group and an SP value of 10.7 was used as the surface conditioner instead of surface conditioner D. The weight ratio (D) of this coating agent was 2.04%. In addition, the ratio (R/T) of the particle diameter R of silica particles B to the film thickness T of coating film 1 was 0.15.

In Comparative Example 8, a coating film was obtained in the same manner as in Example 1, except that 3.0 g of a hydrophilic silicone additive (TEGO Glide 440, manufactured by Evonik Japan Co., Ltd.) containing no OH groups and having an SP value of 14.2 was used as the surface conditioner instead of surface conditioner D. The ratio (R/T) of the particle diameter R of silica particles B to the thickness T of coating film 1 was 0.15.

In Comparative Example 9, an attempt was made to obtain a coating film, etc., in the same manner as in Example 1, except that 3.0 g of a low-compatible group-modified fluorine additive (DSX-E, manufactured by Daikin Industries, Ltd.) with an SP value of less than 8 and no OH group was used as the surface conditioner instead of Surface Conditioner D. However, the coating agent aggregated, and a proper coating film could not be obtained.

In addition, in Comparative Examples 6, 8, and 9, the ratio of the mass of the surface conditioner not containing an OH group to the total solid mass of the hydroxyl group-containing resin (A) and the polyisocyanate (C) (for convenience of explanation, this is shown in the column for weight ratio (D) in Table 1 described later) is 2.04%.

In Comparative Example 10, instead of the hydroxyl group-containing resin (A) and polyisocyanate (C), 363.3 g of a urethane resin (MAU-2600, manufactured by Dainichiseika Chemicals Co., Ltd.) with a solid content (non-volatile content) of 40%, a weight average molecular weight of 45,000, and substantially no hydroxyl group was used as the binder resin, and the amount of solvent was adjusted so that the solid content concentration of the coating agent was 30%. A coating film and the like were obtained in the same manner as in Example 1. The ratio of the mass of the surface conditioner (D) to the solid content mass of the binder resin component (shown in the column of weight ratio (D) for convenience of explanation in Table 1 described later) is 2.04%. In addition, the ratio (R/T) of the particle diameter R of the silica particles B to the thickness T of the coating film 1 is 0.15.

The formulations and physical properties of the coating agents of the above examples and comparative examples are shown in Table 1. The amount of solvent is omitted. The difference values of "SP(A)-SP(D)" and "SP(C)-SP(D)" are also shown. In the formulations of Comparative Examples 2, 6, 8, and 9, the surface conditioner D is not used, so these difference values cannot be calculated. In the formulation of Comparative Example 10, the hydroxyl group-containing resin (A) and polyisocyanate (C) are not used, so these difference values cannot be calculated. In Comparative Example 6, the SP value of the hydrophobic fluorine additive that does not contain a hydroxyl group is used instead of the SP value of the surface conditioner D (SP(D)), and the value corresponding to the difference value is calculated and listed in Table 1. In Comparative Example 8, the SP value of the hydrophilic silicone additive is used instead of the SP value of the surface conditioner D (SP(D)), and the value corresponding to the difference value is calculated and listed in Table 1. In addition, in the formulation of Comparative Example 9, the SP value of the low-compatible group-modified fluorine additive could not be properly measured, so the value corresponding to the difference value is omitted.

The coating films of the above examples and comparative examples were subjected to the following tactile evaluation based on the indices of smoothness and moistness (hereinafter simply referred to as tactile evaluation), abrasion resistance evaluation, and chemical resistance evaluation. In the following evaluations, both the smoothness and moistness are tactile sensations that constitute a nubuck-like feel.

(Tactile evaluation)
The smoothness and moistness were evaluated by a sensory test (touch) when the evaluator stroked the coating surface with the pad of his/her finger or the palm of his/her hand. There were 10 evaluators. The touch was evaluated by each evaluator on a 5-point scale from 5 points to 1 point, starting from the best. The average score of all the evaluators was then calculated. Based on this average score, the average score was rated on a 4-point scale: A for more than 4 and 5 or less, B for more than 3 and 4 or less, C for more than 2 and 3 or less, and D for 1 to 2 or less. The evaluation results are also shown in Table 1. The relationship between the score of the smoothness and the impression of the touch is shown in Table 2, and the relationship between the score of the moistness and the impression of the touch is shown in Table 3.

The tactile test was conducted before and after the chemical resistance evaluation described below. In Table 1, the smoothness and moistness based on the tactile test conducted before the chemical resistance evaluation are noted as "initial." Furthermore, the smoothness and moistness based on the tactile test conducted after the chemical resistance evaluation are noted as "after the chemical resistance test."

(Wear resistance evaluation)
A test piece measuring 250 mm in length and 30 mm in width was cut out from the coated film and fixed to the test stand of a rubbing tester (RT-200, manufactured by Daiei Kagaku Seiki Seisakusho). Then, Kanakin No. 3 was attached twice to the friction element, and a wear test was performed under the conditions of a surface pressure of 100 g/ ^cm2 , a speed of 10 cm/second, and 500 reciprocating strokes. Then, according to the degree of appearance change (visual observation) after the friction test, it was rated on a four-level scale from A to D, in order of best to worst. The relationship between the appearance score and the visual impression is shown in Table 4.

(Chemical resistance evaluation)
The chemical resistance tests were carried out in the following three types of tests 1 to 3, and the evaluations of the Examples and Comparative Examples were classified based on the average score of each test.

(Test 1)
A car seat cleaner (a moist, long-lasting leather cleaner, manufactured by Soft99 Corporation) was applied to gauze, and the coating surface of the film with the coating was wiped off under the conditions of a surface pressure of 100 g/ ^cm2 , a speed of 10 cm/sec, and 10 reciprocating strokes. The appearance change (visual observation) after the wiping test was then rated on a 5-point scale from best to worst, ranging from 5 points to 1 point. The relationship between the appearance score and the visual impression is shown in Table 5.

(Test 2)
A 70% by weight aqueous solution of ethanol (a liquid formulation for a disinfectant spray) was applied to gauze, and the coating surface of the film with the coating was wiped off under the conditions of a surface pressure of 100 g/ ^cm2 , a speed of 10 cm/sec, and 10 reciprocating strokes. The appearance change (visual observation) after the wipe-off test was evaluated on a 5-point scale from best to worst, ranging from 5 points to 1 point. The relationship between the appearance score and the visual impression is the same as in Table 5.

(Test 3)
Petroleum benzine was applied to gauze, and the coating surface of the coated film was wiped off under the conditions of a surface pressure of 100 g/ ^cm2 , a speed of 10 cm/sec, and 10 reciprocating strokes. The appearance change (visual observation) after the wiping test was evaluated on a 5-point scale from 5 points for best to 1 point for worst. The relationship between the appearance score and the visual impression is the same as in Table 5.

Based on the average values of tests 1 to 3 above, the average was rated on a four-point scale: A for over 4 and under 5, B for over 3 and under 4, C for over 2 and under 3, and D for over 1 and under 2.

The results of each of the above evaluations are shown in Table 1 above. Note that for the coating film of Comparative Example 9, the results of the tactile evaluation, abrasion resistance evaluation, and chemical resistance evaluation are omitted because the coating agent aggregated and could not properly form a coating film. In the following, the tactile evaluation, abrasion resistance evaluation, and chemical resistance evaluation for the coating film of Comparative Example 9 are treated as D ratings. Because the evaluation results of Comparative Example 9 were clearly poor, a discussion of the evaluation results of Comparative Example 9 is omitted below.

As shown in Table 1, the evaluation values of the tactile evaluation, abrasion resistance evaluation, and chemical resistance evaluation of each example (hereinafter, these may be collectively referred to simply as evaluation values) do not include a D rating. In contrast, the evaluation values of all comparative examples include a D rating. In this way, the coatings etc. of this embodiment (examples) show generally better evaluation results than the coatings of the comparative examples.

In particular, the evaluation results of Example 8 show that surface conditioner D is not limited to silicone-based materials, and that even fluorine-based materials can achieve a good feel as long as they have OH groups and satisfy the SP value regulations.

The evaluation results of Comparative Examples 1 to 9 show that unless the coating agent contains the silica particles (B) and surface conditioner D according to this embodiment, it is not possible to achieve both a smooth feel and a moist feel.

The evaluation results of Comparative Example 10 show that if the coating agent does not contain the hydroxyl group-containing resin (A), it will not have chemical resistance and will not be able to maintain a good tactile feel for a long period of time.

Figures 3 and 4 show optical microscope photographs of the coating surface of Example 7. Figure 5 shows an optical microscope photograph of the coating surface of Comparative Example 1. Comparison of the coating surfaces of both shows that when silica particles (B) are not formulated in the coating agent, unevenness occurs on the coating surface. In other words, when silica particles (B) are not formulated in the coating agent, the dispersion state of surface conditioner D on the coating surface deteriorates. This tendency can also be understood from the tendency that the moist feeling caused by surface conditioner D decreases slightly when the amount of silica particles (B) is reduced in a relative comparison between Examples 1 and 3 and Example 4.

In particular, the evaluation results of Comparative Examples 3 and 4 show that even when the filler is silica particles, unless the particle size R of the silica particles is 0.1 μm or more and 5 μm or less, it is not possible to achieve both a smooth feel and a moist feel, even if abrasion resistance is obtained.

The evaluation results of Comparative Example 5 also show that even if particles other than silica particles (B) are formulated as a filler and the particle diameter R of the particles formulated as the filler is 0.1 μm or more and 5 μm or less, it is not possible to achieve both a smooth feel and a moist feel. Figure 6 shows an optical microscope photograph of the coating surface of Comparative Example 5. From Figure 6, it can be seen that, as in the case of Comparative Example 1 shown in Figure 5, unevenness occurs on the coating surface, and therefore the dispersion state of surface conditioner D on the coating surface has deteriorated.

According to the evaluation results of Comparative Examples 6 and 8, when the coating agent does not contain surface conditioner D, i.e., when the additive added as a surface conditioner does not contain a hydroxyl group, the tactile sensation after the chemical resistance test is significantly reduced even if the initial tactile sensation evaluation is relatively good. This is because the additive added as a surface conditioner cannot form a bond with the polyisocyanate (C). In other words, in the chemical resistance test, the additive added as a surface conditioner is not fixed to the coating surface and easily falls off. In Comparative Example 10, since no hydroxyl group-containing resin (A) is used and no polyisocyanate (C) is formulated, it is considered that even if surface conditioner D is formulated, surface conditioner D is not fixed to the coating surface and easily falls off.

In addition, the evaluation results of Comparative Example 7 show that when the composition of the coating agent does not satisfy the predetermined relationship regarding the SP value, the moist feeling may be insufficient compared to the coating film of the Examples. This is thought to be because it becomes difficult to properly realize the structure of the coating film 1 as in the Examples.

In addition, the evaluation results of Comparative Example 8 show that when the coating agent does not contain surface modifier D, even if the coating agent or coating film contains silica particles (B), the abrasion resistance may be significantly reduced compared to the coating film of the Examples. This is thought to be because, when the coating agent contains silica particles (B) and surface modifier D, as in the Examples, a structure is realized in which the silica particles (B) are properly dispersed and unevenly distributed on the coating film surface, improving the abrasion resistance.

In this way, it is possible to provide a thermosetting coating composition, coating film, and laminate that can achieve a nubuck-like, pleasant feel with excellent smoothness and moistness.

The configurations disclosed in the above embodiment (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided no contradictions arise. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments. Appropriate modifications can be made without departing from the scope of the present invention.

The present invention can be applied to thermosetting coating compositions, coating films and laminates using the same.

1 Coating film 2 Binder resin 100 Laminate B Silica particles D Surface conditioner

Claims (7)

A thermosetting coating composition comprising a hydroxyl group-containing resin (A), silica particles (B), a polyisocyanate (C) and a hydroxyl group-containing surface conditioner (D),
The hydroxy group-containing surface conditioner (D) contains one or more skeletons selected from the group consisting of a silicone skeleton and a fluororesin skeleton,
When the SP values of the hydroxyl group-containing resin (A), the polyisocyanate (C) and the hydroxyl group-containing surface conditioner (D) are SP(A), SP(C) and SP(D), respectively, the following formulas (1) and (2):
1.0≦SP(A)-SP(D)≦2.5 (1)
1.0≦SP(C)-SP(D)≦2.5 (2)
Fulfilling
The heat-curable coating composition, wherein the silica particles (B) have a volume-based 50% particle size R of 0.1 μm or more and 5 μm or less. The thermosetting coating composition according to claim 1, wherein the silica particles (B) are hydrophilic silica particles. The thermosetting coating composition according to claim 1 or 2, wherein the mass of the hydroxyl group-containing surface conditioner (D) is 0.5% or more and 5.0% or less of the total solid mass of the hydroxyl group-containing resin (A) and the polyisocyanate (C). The thermosetting coating composition according to any one of claims 1 to 3, wherein the OH value of the hydroxyl group-containing resin (A) is 10 mg KOH/g or more and 200 mg KOH/g or less. A coating film using the thermosetting coating composition according to any one of claims 1 to 4. The coating film according to claim 5, wherein the ratio (R/T) of the 50% particle diameter R of the silica particles (B) to the thickness T of the coating film is 0.02 or more and 0.5 or less. A polymer resin substrate;
A laminate comprising the coating film according to claim 5 or 6 disposed on the polymeric resin substrate.

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