JP2023036202A - Coating composition - Google Patents

Abstract

To provide a coating composition that can give a smooth comfortable feel.SOLUTION: A coating composition contains a methacrylic resin having a hydroxy group, a polyisocyanate compound, and particles with an average particle size of 1.0 μm or more and 100.0 μm or less. The methacrylic resin has a polysiloxane skeleton.SELECTED DRAWING: None

Description

The present invention relates to coating compositions.

In recent years, plastic products that are often touched by human hands, such as automotive interior parts such as instrument panels and center consoles, electrical and electronic equipment related parts such as computer housings, lifestyle related parts, and furniture and building material related parts. There is an increasing demand for non-sticky and smooth touch.

Patent Document 1 discloses a composition for forming a natural leather topcoat film containing a polyurethane resin or polyurethane acrylic resin, silica fine particles or polyurethane resin fine particles, an aqueous polyaliphatic isocyanate cross-linking agent, and a silicone-based tactile agent. .
In Patent Document 2, a coated metal plate coated with a coating layer having a glass transition temperature and a number average molecular weight within a predetermined range and having a topcoat layer containing a silicone-acrylic resin compound graft-polymerized with a polysiloxane chain and an isocyanate is provided. disclosed.

JP 2013-040259 A JP 2014-131838 A

In Patent Document 1, when a highly hydrophobic silicone-based tactile agent is added, it is unevenly incorporated into the coating film due to poor compatibility with polyurethane resins and polyacrylic resins, and sufficient smoothness cannot be obtained. In addition, the silicone-based tactile agent may be eluted (bleed) onto the surface of the coating film, adversely affecting the tactile feel.
In addition, in Patent Document 2, since the content of the silicone/acrylic resin in the topcoat layer component is small, the content of the graft-polymerized polysiloxane chain is also small, and a sufficient smooth feeling when touched with a finger is obtained. It is feared that it will not be obtained.

The present invention has been made in view of such circumstances. SUMMARY OF THE INVENTION An object of the present invention is to provide a coating composition that can provide a smooth and comfortable feel.

The inventors of the present invention have extensively studied a coating composition for solving the above problems from various viewpoints. As a result, the present inventors have found that the above problems can be solved by introducing a polysiloxane compound into a (meth)acrylic resin and containing particles in a predetermined range in a coating composition.

According to the invention,
a (meth)acrylic resin having a hydroxy group;
a polyisocyanate compound;
and particles having an average particle diameter of 1.0 μm or more and 100.0 μm or less,
A coating composition is provided in which the (meth)acrylic resin has a polysiloxane skeleton.

ADVANTAGE OF THE INVENTION According to this invention, the coating composition which can acquire the smooth touch when a finger touches a coating film is provided.

Hereinafter, embodiments of the present invention will be described in detail.

In this specification, the notation "X to Y" in the description of numerical ranges means X or more and Y or less, unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less".

In the description of a group (atomic group) in the present specification, a description without indicating whether it is substituted or unsubstituted includes both those having no substituent and those having a substituent. For example, the term “alkyl group” includes not only alkyl groups without substituents (unsubstituted alkyl groups) but also alkyl groups with substituents (substituted alkyl groups).
The notation "(meth)acryl" used herein represents a concept that includes both acryl and methacryl. The same applies to similar notations such as "(meth)acrylate".

<Paint composition>
The coating composition of this embodiment is
a (meth)acrylic resin having a hydroxy group;
a polyisocyanate compound;
Particles with an average particle size of 1.0 μm or more and 100.0 μm or less,
including.
The (meth)acrylic resin has a polysiloxane skeleton.

With the coating composition of the present embodiment, a coating composition capable of providing a smooth feel can be obtained. Although the details of this mechanism are not clear, it can be explained as follows. As a reminder, the following description does not limit the scope of the invention.

The coating composition used in this embodiment contains particles of a predetermined size in a curing system of a (meth)acrylic resin having a hydroxyl group and a polysiloxane skeleton and a polyisocyanate compound.
An example of the coating composition is an acrylic urethane coating that has a high degree of freedom in design and is excellent in workability and coating properties. Further, as an example of imparting a smooth feel to a coating film, there is a method of adding a compound having a polysiloxane skeleton (hereinafter referred to as "polysiloxane compound") to the coating material. In general, the higher the content of polysiloxane compounds in the coating film, the easier it is to obtain a smoother touch. Due to the poor compatibility of the agent with the polyisocyanate compound, unreacted substances of the polysiloxane compound tend to remain, and the unreacted substances are eluted on the surface of the coating film, resulting in a slimy feeling on the coating film and poor tactile sensation. end up
In this embodiment, the polysiloxane compound was added during the synthesis of the (meth)acrylic resin and introduced in such a manner as to be chemically bonded to the (meth)acrylic resin. By doing so, the compatibility with hydroxy group-containing (meth)acrylic resins, etc. is greatly improved compared to when the polysiloxane compound is added alone (without chemical bonding), and elution due to unreacted substances can be suppressed, and a coating film with a suitable touch can be obtained.
In addition, by keeping the particle size within an appropriate range, some of the particles protrude appropriately on the surface of the coating film, reducing the contact area when touched with a finger, and providing a smooth and comfortable touch. It is considered possible.

((meth)acrylic resin)
The coating composition in this embodiment contains a (meth)acrylic resin.
A (meth)acrylic resin means a resin (polymer) containing a structural unit derived from a monomer of (meth)acrylic acid and/or (meth)acrylic acid ester. That is, the (meth)acrylic resin may partially contain structural units derived from non-(meth)acrylic monomers. However, from the viewpoint of sufficiently obtaining the effect derived from the (meth)acrylic structure, the (meth)acrylic resin is preferably 50% by mass or more of the total structural units (more preferably, 80% by mass of the total structural units above) is a structural unit derived from a monomer of (meth)acrylic acid and/or (meth)acrylic acid ester.

From another point of view, the (meth)acrylic resin may have at least one partial structure selected from the group consisting of polycaprolactone, polycaprolactam, polycarbonate, polyester and polyether. Since these chemical structures are moderately flexible and elastic, they can increase the flexibility and elasticity of the coating film.
These partial structures are preferably present in the side chains of the (meth)acrylic resin.

Also, the (meth)acrylic resin preferably does not contain a fluoroalkyl group. Although the detailed mechanism is not clear, this makes it possible to more effectively impart a smooth feel to the coating film. In addition, the compatibility between the (meth)acrylic resin and other components in the coating composition, such as the polyisocyanate compound, can be improved. Furthermore, the dispersibility of the particles in the coating composition can be improved. Therefore, it is considered that a smooth touch can be imparted to the coating film.
From the same point of view, the (meth)acrylic resin preferably does not contain fluorine.

The (meth)acrylic resin in the present embodiment preferably comprises one or more (meth)acrylic monomers selected from the group consisting of the following (i) to (iv) as structural units, and (v) and polysiloxane compounds.
As the (meth)acrylic monomer, those represented by the general formula CH ₂ =CR-COO-R' are preferred. Here, R is a hydrogen atom or a methyl group, and R' is a hydrogen atom or a monovalent organic group. The monovalent organic group for R' is preferably an alkyl group, a monocyclic or polycyclic cycloalkyl group, an aryl group, or an aralkyl group, and these groups may further have a substituent.
Two or more kinds of (meth)acrylic monomers may be selected from those corresponding to (i), for example.

(i) in the general formula CH ₂ =CR-COO-R', R' is a monovalent organic group, and the organic group is an alkyl group, a monocyclic or polycyclic cycloalkyl group, an aryl group, or an aralkyl group; A monomer that is a radical.
Specific examples thereof include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-stearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate and the like.
Among these, those in which R′ is an alkyl group with a small number of carbon atoms have a high glass transition temperature (° C.), and those in which R′ is an alkyl group with a large number of carbon atoms have a glass transition temperature (° C.). lower. Depending on the desired glass transition temperature (° C.) of the (meth)acrylic resin, monomers of alkyl groups having different carbon numbers for R′ can be used in combination.

When the (meth)acrylic resin contains a structural unit derived from this monomer, its content is preferably 0.5 to 80% by mass, relative to 100% by mass of the total structural units of the (meth)acrylic resin, and more It is preferably 0.7 to 70% by mass, more preferably 1 to 60% by mass.

(ii) a monomer having the general formula CH ₂ =CR-COO-R' in which the monovalent organic group of R' is substituted with a polar group such as a hydroxy group;
Specific examples thereof include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate and the like.
When the (meth)acrylic resin contains a structural unit derived from this monomer, the content thereof is preferably 1 to 40% by mass, more preferably 100% by mass of the total structural units of the (meth)acrylic resin. 5 to 30% by mass.

(iii) A monomer having the general formula CH ₂ =CR-COO-R', wherein R' contains at least one partial structure selected from the group consisting of polycaprolactone, polycaprolactam, polycarbonate, polyester and polyether.
Specific examples thereof include Daicel Corporation's product name "PLAXEL F" series, methoxypolyethylene glycol mono(meth)acrylate having 3 to 20 moles of ethylene oxide addition, polypropylene glycol mono(meth)acrylate, 2-(2-ethoxy ethoxy)ethyl acrylate, and the like.
A resin containing a structural unit derived from the above monomer (iii) is considered particularly preferable from the viewpoint of improving the flexibility of the coating film.
When the (meth)acrylic resin contains a structural unit derived from this monomer, the content thereof is preferably 1 to 60% by mass with respect to 100% by mass of the total structural units of the (meth)acrylic resin, and more It is preferably 5 to 50% by mass.

(iv) A monomer represented by the general formula CH ₂ =CR-COO-R', wherein R' is a hydrogen atom.
A specific example of this is (meth)acrylic acid.
When the (meth)acrylic resin contains a structural unit derived from this monomer, the content thereof is preferably 0.1 to 10% by mass with respect to 100% by mass of the total structural units of the (meth)acrylic resin. , more preferably 0.5 to 5% by mass.

(v) is a polysiloxane compound.
By using (v) when synthesizing the (meth)acrylic resin of the present embodiment, a polysiloxane skeleton can be introduced into the (meth)acrylic resin.
The details of the polysiloxane compound will be described later together with the method of introducing it when synthesizing the (meth)acrylic resin.

The (meth)acrylic resin in the coating composition of this embodiment has a hydroxy group. A hydroxyl group of the (meth)acrylic resin reacts with an isocyanate group of the polyisocyanate compound described later to form a crosslinked structure.

As a method for quantifying hydroxyl groups contained in (meth)acrylic resins, it is known to use a hydroxyl value. More specifically, the (meth)acrylic resin preferably has a hydroxyl value of 20 mgKOH/g or more, more preferably 30 to 150 mgKOH/g, and further preferably 50 to 120 mgKOH/g. Preferably, 50 to 115 mg KOH/g is even more preferred.
By setting it as this numerical range, the polyisocyanate compound and (meth)acrylic resin mentioned later react appropriately, and a crosslinked structure is controlled appropriately. Therefore, the glass transition temperature of the coating film can be increased while maintaining the flexibility and elasticity of the coating film.
The hydroxyl value is the number of mg of potassium hydroxide required to neutralize the acetic acid bound to the hydroxyl group when 1 g of the sample is acetylated. Specifically, JIS K 0070 "Test method for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products", "7.1 Neutralization titration method" specified Measure and calculate according to the method.

The (meth)acrylic resin in the coating composition of this embodiment has a polysiloxane skeleton.
As a method of introducing the above-described (v) polysiloxane compound during the synthesis of the (meth)acrylic resin, the following four methods can be mentioned.
(1) A method of radically polymerizing a polysiloxane compound having a radically polymerizable group with the (meth)acrylic monomers described in (i) to (iv) above.
A (meth)acryloyl group is mentioned as a radically polymerizable group.
Commercially available polysiloxane compounds having a radically polymerizable group include, for example, Silaplane FM-0711, FM-0721 and FM-0725 manufactured by JNC Co., Ltd., X-22-174BX and KF-2012 manufactured by Shin-Etsu Silicone Co., Ltd. is mentioned.
(2) A method of introducing a polysiloxane compound having a reactive functional group by reacting it with a reactive group previously introduced into a (meth)acrylic resin.
A hydroxyl group, an epoxy group, a carboxy group, an amino group, etc. are mentioned as a reactive functional group.
Examples of commercially available polysiloxane compounds having a reactive functional group include Silaplane (trade name) series such as Silaplane FM-0421 and FM-4421 manufactured by JNC Co., Ltd., and X-22-173DX manufactured by Shin-Etsu Silicone Co., Ltd. and resin-modified modified silicone oils such as X-22-170DX.
(3) A method of introducing a block copolymer by polymerizing the above-mentioned (meth)acrylic monomer using a polymeric azo polymerization initiator having a polysiloxane skeleton.
Commercially available polymeric azo polymerization initiators include, for example, polydimethylsiloxane unit-containing polymeric azo polymerization initiator VPS-1001N (trade name) manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.
(4) A method of introducing a block copolymer by using a polysiloxane compound having a mercapto group as a chain transfer agent when polymerizing the above-described (meth)acrylic monomer.
Examples of commercially available polysiloxane compounds having a mercapto group include X-22-167B manufactured by Shin-Etsu Silicone Co., Ltd., and the like.
By using the above-mentioned methods (1) to (4), the polysiloxane skeleton can be introduced into the central portion or end of the main skeleton of the (meth)acrylic resin, or into the side chains.

As the above-mentioned (v) polysiloxane compound, it is preferable to use a polydimethylsiloxane compound from the viewpoint of imparting a smooth feel to the coating film more effectively.

The number average molecular weight (Mn) of the structural unit having a polysiloxane skeleton in the (meth)acrylic resin is preferably 500 or more, more preferably 700 or more, still more preferably 1000 or more, preferably 20000, for example, in terms of catalog values. or less, more preferably 15,000 or less, and even more preferably 10,000 or less.
By making the range of the number average molecular weight (Mn) equal to or higher than the above lower limit, it is possible to impart a smooth feeling to the coating film. In addition, it is believed that by setting the number average molecular weight (Mn) to the above upper limit or less, the polysiloxane compound is easily incorporated into the (meth)acrylic resin, and the generation of unreacted substances can be suppressed. By setting the number average molecular weight (Mn) to the above upper limit or less, the compatibility between the polysiloxane compound and the (meth)acrylic resin is improved, and the polysiloxane compound is present as an unreacted substance, thereby preventing the occurrence of slimy feeling. considered to be suppressed.

The content of the structural unit having a polysiloxane skeleton in the (meth)acrylic resin in the present embodiment is preferably 0.1% by mass or more, more preferably 0, based on 100% by mass of the total solid content of the coating composition. .3% by mass or more, preferably 20% by mass or less, and more preferably 15% by mass or less. By setting the content of the structural unit having a polysiloxane skeleton in the (meth)acrylic resin within the above range, it is possible to introduce an amount of polysiloxane skeleton that can impart a sufficiently smooth feeling to the coating film. , the tactile sensation of the coating film can be improved.

The weight average molecular weight (Mw) of the (meth)acrylic resin is preferably from 5,000 to 50,000, more preferably from 7,000 to 40,000, even more preferably from 10,000 to 30,000, and preferably from 15,000 to 25,000. Especially preferred.
By making it more than this lower limit, the adhesiveness of a coating film to the board|substrate can be made favorable. Further, by making the content equal to or less than this upper limit, generation of air bubbles in the coating film is suppressed, and a good coating film can be obtained.
The weight-average molecular weight (Mw) of the (meth)acrylic resin can be adjusted by conditions such as polymerization reaction time, reaction temperature, and amount of polymerization initiator used.
The number average molecular weight Mn and the weight average molecular weight Mw can be measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

The (meth)acrylic resin preferably has a glass transition temperature (°C) of 1 to 80°C, more preferably 1 to 75°C. By setting it within the above range, it becomes easier to adjust the glass transition temperature of the coating composition (excluding particles), as will be described later. Further, by setting the amount within the above range, the compatibility between the (meth)acrylic resin and the isocyanate curing agent, etc., can be improved, and the handleability during synthesis of the coating composition can be improved.
The glass transition temperature (° C.) of the (meth)acrylic resin can be calculated from the compounding ratio of the monomers used using the following Fox formula.
1/Tg=( _W1 / _Tg1 )+( _W2 / _Tg2 )+( _W3 / _Tg3 )+...+( _Wn / _Tgn )
_[ Wherein, Tg is _the glass transition temperature ₍ K) of _the resin, W ₁ , W ₂ , W ₃ . _n indicates the glass transition temperature (K) of a homopolymer composed of monomers corresponding to the mass fraction of each monomer. ]

In this specification, the glass transition temperature of the (meth) acrylic resin (not the glass transition temperature of the coating composition for measuring the glass transition temperature excluding particles from the coating composition described later, but the glass transition of the (meth) acrylic resin alone temperature) means the glass transition temperature determined based on the above formula.
For monomers with unknown glass transition temperatures such as special monomers and polyfunctional monomers, the glass transition temperatures are determined using only monomers with known glass transition temperatures.

The content of the (meth) acrylic resin is preferably 1% by mass or more, preferably 2% by mass or more, and preferably 80% by mass or less with respect to 100% by mass of the total solid content of the coating composition. Yes, more preferably 75% by mass or less. In particular, when the coating composition does not contain a polyol described later, the content of the (meth)acrylic resin is 60% by mass or more and 80% by mass or less with respect to 100% by mass of the total solid content of the coating composition. Preferably. This amount is appropriately determined from the handleability, coatability, etc. of the paint.

The method for producing the (meth)acrylic resin is not particularly limited, and known methods can be applied as appropriate. For example, it is preferably produced by a polymerization reaction, and more preferably produced by a radical polymerization. Moreover, the polymerization may be any known method such as solution polymerization, suspension polymerization, and emulsion polymerization. Of these, solution polymerization is preferred from the viewpoint of precise control of polymerization.

A known polymerization initiator can be used as the polymerization initiator for radical polymerization. For example, 1,1-azobis-1-cyclohexanecarbonitrile, azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2-methylpropionitrile), and Azo initiators such as 2,2-azobis(2,4-dimethylvaleronitrile), benzoyl peroxide, t-butyl peroxyoctanoate, diisobutyl peroxide, di(2-ethylhexyl) peroxypivalate, deca Peroxide initiators such as noyl peroxide, t-butyl peroxy-2-ethylhexanoate, and t-butyl peroxybenzoate, hydrogen peroxide and iron(II) salts, persulfates and sodium bisulfite and redox initiators in which an oxidizing agent and a reducing agent are combined. These can be used individually by 1 type or in combination of 2 or more types.
The amount of the polymerization initiator to be blended is not particularly limited, but is preferably 0.001 to 10 parts by mass when the total mixture of monomers to be polymerized is 100 parts by mass.

Further, in the polymerization reaction, known chain transfer agents, polymerization inhibitors, molecular weight modifiers and the like may be used as appropriate. Furthermore, the polymerization reaction may be carried out in one step or in two or more steps. Although the temperature of the polymerization reaction is not particularly limited, it is appropriately adjusted in consideration of the 10-hour half-life temperature of the polymerization initiator. It is typically in the range of 50°C to 200°C, preferably 80°C to 150°C.

(polyol)
The coating composition of this embodiment preferably contains a polyol, that is, a compound having two or more hydroxy groups in one molecule. A polyol can react with a polyisocyanate compound described later. Then, the coating film can be cured.
The number of hydroxy groups per molecule of the polyol is usually 2 or more, preferably 2-6, more preferably 2-4.
The (meth)acrylic resin described above contains a hydroxy group and is generally classified as a polyol, but the polyol in the present embodiment excludes the (meth)acrylic resin described above.

The polyol preferably contains at least one polyol selected from the group consisting of polycaprolactone polyols, polycarbonate polyols, polyester polyols and polyether polyols. These chemical structures are moderately flexible and elastic. Therefore, the flexibility and elasticity of the coating film can be further enhanced. Therefore, it is desirable in terms of absorption of external force.

Polycaprolactone polyol can be used without any particular limitation as long as it is a compound having an open ring structure of caprolactone and two or more hydroxy groups in one molecule. Specifically, the following general formula (P-1) and polyols represented by any one of (P-3).

In general formula (P-1),
R represents a divalent organic group. Examples of divalent organic groups include straight-chain alkylene groups such as —CH ₂ — and —C ₂ H ₄ —, branched alkylene groups such as —CH ₂ —C(CH ₃ ) ₂ —CH ₂ —, and —C and ether-containing groups such as ₂ H ₄ -OC ₂ H ₄ -.
Each X is independently a linear or branched alkylene group. The alkylene group preferably has 3 to 7 carbon atoms, more preferably 4 to 6 carbon atoms.
m and n each independently represent an integer of 1 or more. Each of m and n is preferably an integer of 2-20. Also, the sum of m and n is preferably 4-35.

In general formula (P-2),
R represents a trivalent organic group. The trivalent organic group includes, for example, a structure obtained by removing three hydrogen atoms from a linear or branched alkane.
Each X is independently a linear or branched alkylene group. The alkylene group preferably has 3 to 7 carbon atoms, more preferably 4 to 6 carbon atoms.
l, m and n each independently represent an integer of 1 or more. l, m and n are each preferably an integer of 2-20. Also, the sum of l, m and n is preferably 3-40.

In general formula (P-3),
R represents a tetravalent organic group. The tetravalent organic group includes, for example, a structure obtained by removing four hydrogen atoms from a linear or branched alkane.
Each X is independently a linear or branched alkylene group. The alkylene group preferably has 3 to 7 carbon atoms, more preferably 4 to 6 carbon atoms.
k, l, m and n each independently represent an integer of 1 or more. Each of k, l, m and n is preferably an integer of 2-20. Also, the sum of k, l, m and n is preferably 4-50.

Commercially available products of polycaprolactone polyol include, for example, Daicel Co., Ltd.'s product names such as PLAXEL 200 series, PLAXEL 300 series, PLAXEL 400 series, and the like.

Any polycarbonate polyol can be used without particular limitation as long as it is a compound having a carbonate group represented by —O—(C═O)—O— and two or more hydroxy groups in one molecule.
Polycarbonate polyol can be obtained by reacting one or more polyol raw materials (polyhydric alcohol) with carbonic acid ester or phosgene.
Polyol raw materials are not particularly limited, and examples thereof include aliphatic polyols, polyols having an alicyclic structure, and aromatic polyols. In the present embodiment, an aliphatic polyol having no alicyclic structure is preferred from the viewpoint of the flexibility of the coating film.
Carbonic acid esters include, for example, aliphatic carbonic acid esters such as dimethyl carbonate and diethyl carbonate, aromatic carbonic acid esters such as diphenyl carbonate, and cyclic carbonic acid esters such as ethylene carbonate. Of these, aliphatic carbonates are preferred, and dimethyl carbonate is particularly preferred, because of their availability and ease of production.
Commercially available polycarbonate polyols include, for example, Duranol (trade name) series manufactured by Asahi Kasei Corporation.
Among polycarbonate polyols, it is particularly preferable to include polycarbonate diol. As a result, when the coating film is touched with a finger, a soft touch can be obtained. Further, by lowering the Martens hardness of the coating film to be described later and increasing the flexibility and elasticity of the coating film, the occurrence of cracks during film formation can be suppressed.

Any compound having an ester group (--COO-- or --OCO--) and two or more hydroxy groups in one molecule can be used as the polyester polyol without any particular limitation.
A polyester polyol can be obtained by reacting one or more polyol raw materials (polyhydric alcohol) with an ester-forming compound such as a polycarboxylic acid or its ester, anhydride, or halide.
The polyol raw material is not particularly limited, and the same polyol raw material as the raw material for the above-described polycarbonate polyol can be used.
Ester-forming compounds such as polycarboxylic acids or their esters, anhydrides, and halides are not particularly limited, and polycarboxylic acids such as aliphatic dicarboxylic acid compounds, aromatic dicarboxylic acid compounds, alicyclic dicarboxylic acid compounds, tricarboxylic acid compounds, etc. Carboxylic acids, acid anhydrides of these polycarboxylic acids, halides, lower ester compounds and the like can be mentioned.

Any compound having an ether bond (--O--) and two or more hydroxy groups in one molecule can be used as the polyether polyol without any particular limitation.
Specific compounds include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, random copolymers and block copolymers of ethylene oxide and propylene oxide, and ethylene oxide and butylene oxide.

In this embodiment, the polyol may be a compound corresponding to a plurality of polycaprolactone polyols, polycarbonate polyols, polyester polyols, and polyether polyols. For example, the polyol may be a polyether polyester polyol or the like having an ether bond and an ester bond.

The molecular weight of the polyol is preferably 300 to 3,000, more preferably 500 to 2,000, for example, in terms of catalog values. By adjusting the molecular weight to an appropriate level, the flexibility and elasticity of the coating film can be improved.
The hydroxyl value of the polyol is preferably 50-300 mgKOH/g, more preferably 100-250 mgKOH/g. By adjusting the amount of hydroxyl groups to an appropriate level, it is expected that the crosslinked structure due to the reaction with the polyisocyanate compound described below will be controlled, and the flexibility, elasticity, etc. of the coating film will be further enhanced.

The content of the polyol in the coating composition is usually 10 to 80% by mass, preferably 15 to 75% by mass, more preferably 20 to 70% by mass, relative to 100% by mass of the total solid content of the coating composition. % by mass. The amount of the polyol is usually 10 to 2500 parts by mass, preferably 20 to 2300 parts by mass, more preferably 30 to 2200 parts by mass based on 100 parts by mass of the (meth)acrylic resin. By setting it to this numerical range, the performance derived from the polyol can be sufficiently obtained, and the balance with other components can be achieved.

In the present embodiment, the glass transition temperature (° C.) of the coating composition for measuring the glass transition temperature excluding particles from the coating composition is preferably −30° C. or higher, more preferably −25° C. or higher, It is also preferably 90° C. or lower, more preferably 85° C. or lower.
When the glass transition temperature is within the above range, it is possible to suppress the feeling that the finger is caught when touched with a finger (tight feeling) due to the coating film being too soft, and the coating film being too hard. , the occurrence of cracks during film formation and practical use can be suppressed.
In addition, the coating composition for measuring the glass transition temperature obtained by removing the particles from the coating composition is the material constituting the coating composition other than the particles, that is, the (meth) acrylic resin, the polyisocyanate compound, and the polyol. refers to polyols and silicone additives when included.

The glass transition temperature (°C) of the coating composition for glass transition temperature measurement obtained by removing the particles from the coating composition is obtained by the following method.
First, the coating composition for measuring the glass transition temperature was applied to a polypropylene substrate by air spray, and the coated substrate was heated at 80°C for 60 minutes. A coating film having a film thickness of 50 μm is obtained by allowing to stand still for a week. The coating film is peeled off from the substrate and cut into pieces having a width of 5 mm and a length of 50 mm to obtain test pieces. Using the test piece, under the conditions of 23 ° C. and 50% relative humidity, the maximum value tan δmax of the loss tangent when dynamic viscoelasticity is measured at a frequency of 1.0 Hz and a temperature in the range of -50 to 180 ° C. is taken as the glass transition. Temperature (°C).

(Polyisocyanate compound)
The coating composition of this embodiment contains a polyisocyanate compound.
The polyisocyanate compound can react with the hydroxyl group of the (meth)acrylic resin to form a crosslinked structure. Also, when the coating composition contains the aforementioned polyol, it can react with the hydroxy groups of the polyol.

The polyisocyanate compound is preferably polyfunctional, that is, a compound having two or more isocyanate groups (including an isocyanate group protected by a leaving group) in one molecule. The number of functional groups of the polyisocyanate compound is more preferably 2 to 6 per molecule, more preferably 2 to 4 per molecule.

Monofunctional isocyanate compounds include aliphatic isocyanates such as methyl isocyanate, butyl isocyanate, hexyl isocyanate and octyl isocyanate, cycloaliphatic isocyanates such as cyclohexyl isocyanate and 4-methylcyclohexyl isocyanate, and phenyl isocyanate, benzyl isocyanate and naphthyl isocyanate. aromatic isocyanates such as

Polyfunctional isocyanate compounds include aliphatic diisocyanates such as lysine isocyanate, hexamethylene diisocyanate and trimethylhexane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4-(or 2,6)-diisocyanate, 4, Cycloaliphatic diisocyanates such as 4′-methylenebis(cyclohexyl isocyanate) and 1,3-(isocyanatomethyl)cyclohexane, and tri- or higher functional isocyanates such as lysine triisocyanate. Isocyanurate and biuret-type adducts, which are polymers of isocyanate compounds, and polyhydric alcohols or low-molecular-weight polyester resins added with isocyanate compounds can also be used as polyisocyanate compounds.

Biuret type, isocyanurate type, adduct type and the like are known as polyisocyanate compounds. In the present embodiment, any of them can be used, but among them, it is preferable to use an isocyanurate-type polyisocyanate compound, that is, a polyfunctional isocyanate having a cyclic skeleton of isocyanuric acid.

The polyisocyanate compound may be a so-called blocked isocyanate. In other words, some or all of the isocyanate groups of the polyisocyanate compound may be in the form of blocked isocyanate groups blocked by protective groups. For example, an isocyanate group is blocked by an active hydrogen compound such as an alcohol, phenol, lactam, oxime, or active methylene compound to form a blocked isocyanate group. In particular, when the coating composition of the present embodiment is a one-liquid system, a polyisocyanate compound having a blocked isocyanate group is preferable from the viewpoint of storage stability (stability over time).

As a commercial product of the polyisocyanate compound, for example, the Duranate (trade name) series manufactured by Asahi Kasei Corporation can be used.

The content of the polyisocyanate compound in the coating composition is usually 10 to 80% by mass, preferably 15 to 75% by mass, based on 100% by mass of the total solid content of the coating composition. The amount of the polyisocyanate compound is usually 10-1500 parts by mass, preferably 15-1400 parts by mass, per 100 parts by mass of the (meth)acrylic resin.
By setting the content of the polyisocyanate compound to the above lower limit or more, the cross-linking between the (meth)acrylic resin and the polyisocyanate compound can be made dense, and a strong coating film can be obtained, and solvent resistance and chemical resistance can be improved. can be improved. In addition, by setting the content of the polyisocyanate compound to the above upper limit or less, it is possible to prevent unreacted isocyanate groups from reacting with moisture in the air after forming a coating film and preventing a suitable coating film from being formed. .

From another point of view, it is preferable to adjust the molar ratio between the hydroxyl group of the (meth)acrylic resin or polyol and the isocyanate group (including the blocked isocyanate group) of the polyisocyanate compound to an appropriate value. This molar ratio is also called the "equivalence ratio". Specifically, the molar ratio (NCO/OH) of the isocyanate group of the polyisocyanate compound to the hydroxyl group of the (meth)acrylic resin or polyol is preferably 0.5 to 1.5, and preferably 0.5 to 0.5. It is more preferably 8 to 1.2. By setting the molar ratio within the above range, suitable physical properties of the coating film can be obtained.

The coating composition of this embodiment may be photosensitive or non-photosensitive, but is preferably non-photosensitive. Moreover, it is more preferably thermosetting. The non-photosensitivity of the coating composition improves the weather resistance of the coating film.

(particle)
The coating composition of this embodiment contains particles.
The lower limit of the average particle diameter of the particles is 1.0 μm or more, preferably 1.5 μm or more. By setting the average particle size of the particles to the above lower limit or more, some of the particles are likely to appear on the coating film surface, so the contact area when a human finger touches the coating film becomes smaller and a smooth touch can be obtained. It is considered possible.
Also, the upper limit of the average particle diameter of the particles is 100.0 μm or less, preferably 50 μm or less, more preferably 30 μm or less, and still more preferably 15 μm or less. If the average particle size is too large, the unevenness of the surface of the coating film becomes large, resulting in a rough feel. be able to.

The average particle size of the particles in this embodiment is measured by the following Coulter Counter method.
The average particle size of particles can be measured using a precision particle size distribution analyzer (for example, "Coulter Counter Multisizer 3" manufactured by Beckman Coulter) and its dedicated software.
An electrolyte solution dedicated to the precision particle size distribution measuring device is put into a beaker dedicated to the precision particle size distribution measuring device and stirred. Remove dirt and air bubbles in the aperture tube of the precision particle size distribution analyzer in advance. Methanol and measurement particles are added to another beaker and dispersed using an ultrasonic cleaner to obtain a measurement sample. The obtained measurement sample is dropped little by little using a pipette into the exclusive beaker of the precision particle size distribution measuring apparatus described above. The measurement density is adjusted to a density at which about 10,000 particles are counted in 10 seconds, and the measurement is continued until the number of measured particles reaches 50,000. Measurement is performed using an appropriate aperture diameter according to the volume average particle diameter of the particles to be measured. The obtained measurement data is analyzed using dedicated software attached to the apparatus, and the volume average particle size is calculated.

The shape of the particles is not particularly limited, but a spherical shape is preferable in consideration of the uniformity of the coating film.

Particles are preferably silica particles, acrylic particles, urethane particles, or crosslinked polyacrylic acid particles. This makes it possible to impart a smooth feeling when the coating film is touched with a finger.
Moreover, the particles preferably do not contain fluororesin particles. Although the detailed mechanism is unknown, this reduces the coefficient of static friction (μS) when formed into a coating film, making it possible to more effectively impart a smooth feel to the coating film.
Only one type of particles may be used, or a plurality of types may be used in combination. The combined use of a plurality of types includes not only the combined use of different materials, but also the combined use of the same materials having different average particle sizes.

The content of particles in the coating composition (the total amount when multiple types of particles are included) is usually 1 to 50% by mass, preferably 3, based on 100% by mass of the total solid content of the coating composition. 40% by mass, more preferably 5 to 40% by mass, still more preferably 8 to 40% by mass, still more preferably 11 to 40% by mass. The amount of the particles is usually 5-2500 parts by weight, preferably 10-2200 parts by weight, per 100 parts by weight of the (meth)acrylic resin.
This numerical range allows the particles to protrude appropriately on the surface of the coating film, imparting a smooth feel to the coating film, and preventing the particles from coming off due to external force.

(Other ingredients)
The coating composition of this embodiment may further contain other components as needed. For example, it may contain a curing accelerator (curing catalyst, etc.), an ultraviolet absorber, a light stabilizer, a dispersant, an antioxidant, and the like.

(solvent)
The coating composition of the present embodiment is typically used by dissolving or dispersing each component in a solvent.
The solvent is an organic solvent as one aspect. Examples of organic solvents include aromatic hydrocarbon solvents such as toluene and xylene; alcohol solvents such as methanol, ethanol, isopropyl alcohol, n-butanol and isobutanol; and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. and ester solvents such as ethyl acetate, propyl acetate, butyl acetate and isobutyl acetate.

The amount of the solvent used is not particularly limited, but it can be used in such an amount that the solid content (non-volatile component) concentration is, for example, 5 to 90% by mass, preferably 10 to 85% by mass.

(Ratio of each component, etc.)
The coating composition of the present embodiment can be expected to provide a smooth tactile sensation when the coating film is touched with a finger by appropriately adjusting the amount ratio of each component.
In particular, in the present embodiment, adjusting the molar ratio of the hydroxy group and the isocyanate group in the coating composition to the range of 0.5 to 1.5 will improve the physical properties of the finally obtained coating film (flexibility, etc. ) is important to improve

(Characteristics of paint composition)
The properties of the coating composition of this embodiment will be described in detail below.

In the present embodiment, the upper limit of the Martens hardness of the coating film is preferably 200 N/mm ² or less, more preferably 170 N/mm ² or less, still more preferably 140 N/mm ² or less. The lower limit of the Martens hardness of the coating film is 1 N/mm ² or more.
When the Martens hardness is equal to or less than the above upper limit value, that is, when the coating film is not too hard, it is possible to suppress cracks in the coating film during film formation or practical use when the film thickness is large. When the Martens hardness is at least the above lower limit value, that is, the coating film is not too soft, it is possible to suppress the stiff feeling when the coating film is touched with a finger, and to impart a smooth touch.

The Martens hardness in this embodiment is measured after forming a coating film.
The coating film is formed by applying the coating composition onto an acrylonitrile/butadiene/styrene copolymer synthetic resin substrate with an air spray, heating the coated substrate at 80°C for 60 minutes, and then heating it at 25°C and relative humidity. A coating film having a film thickness of 20 μm is obtained by allowing to stand for 4 weeks under 50% conditions.
Using the coating film obtained as described above, use a microhardness tester under conditions of 23 ° C. and 50% relative humidity, and apply a Vickers indenter with a load of 4 mN to the coating film for 20 seconds. The Martens hardness is measured by pushing it over. The Martens hardness is calculated by the following formula, where Fmax is the maximum test force and Hmax is the indentation depth by Fmax.
Martens hardness (N/mm ² )=Fmax/(26.43×(Hmax) ² )

In the present embodiment, the upper limit of the coefficient of static friction (μS) of the coating film is preferably 1.4 or less, more preferably 1.2 or less when the Martens hardness is 30 N/mm ² or less. The upper limit of the coefficient of static friction (μS) of the coating film is preferably 1.0 or less, more preferably 0.8 or less when the Martens hardness is greater than 30 N/mm ² .
The coefficient of static friction of the coating film is considered to represent how the coating feels when the finger touches the coating and starts to move it. When the coefficient of static friction is equal to or less than the above upper limit value, a favorable tactile sensation with less stiffness when the coating film is touched with a finger can be obtained.

In the present embodiment, the upper limit of the average dynamic friction coefficient (μK) of the coating film is preferably 0.4 or less, more preferably 0.35 or less when the Martens hardness is 30 N/mm ² or less. . In addition, the upper limit of the average dynamic friction coefficient (μK) of the coating film is preferably 0.4 or less, more preferably 0.3 or less, and still more preferably when the Martens hardness is greater than 30 N/mm ² is 0.25 or less.
The average coefficient of dynamic friction of a coating film is considered to represent how a finger feels while reciprocating the coating film after starting to touch and move the coating film. When the average dynamic friction coefficient of the coating film is equal to or less than the above upper limit, a smooth tactile sensation can be obtained after touching the coating film with a finger and starting to move.

In the present embodiment, when the static friction coefficient of the coating film is μS and the average dynamic friction coefficient is μK, the upper limit of the sum of μS and μK is preferably 1.8 when the Martens hardness is 30 N/mm ² or less. or less, more preferably 1.5 or less. The upper limit of the sum of μS and μK is preferably 1.4 or less, more preferably 1.2 or less, and still more preferably 1.0 or less when the Martens hardness is greater than 30 N/mm ² is.
The sum of μS and μK is a comprehensive evaluation of a good tactile sensation without a stiff feeling when the finger touches the coating film, and a smooth tactile sensation while moving the finger on the coating film after starting to move it. It is useful as an index to
When the sum of μS and μK is equal to or less than the above upper limit, the feeling of slipping when touching the coating film with a finger and the feeling of sliding the finger are combined, and the feeling of tightness is less. A smooth tactile sensation can be felt comprehensively.

A static friction coefficient and an average dynamic friction coefficient are measured by the following methods.
Measurement is performed using the same coating film as that used for measuring the Martens hardness described above. Under the conditions of 23 ° C. and a relative humidity of 50%, the above coating is attached to a static/dynamic friction coefficient measuring machine (TL201Tt, manufactured by Trinity Lab Co., Ltd.), and the tactile contact attached to the measuring machine (hardness equivalent to a fingertip contact) is brought into contact with the coating film under the condition of a contact area of 1.5 cm ² , and the tactile contact is moved 30 mm at a speed of 30 mm / s while applying a load of 10 g, static friction The modulus (μS) and average dynamic coefficient of friction (μK) are measured. The static friction coefficient (μS) is the maximum value of the friction coefficient measured in the range of 0 mm or more and less than 10 mm of the tactile contact, and the measured value of the friction coefficient measured in the range of 10 mm or more and 25 mm or less of the tactile contact. Let the average value of the average dynamic friction coefficient (μK).

In the present embodiment, the arithmetic mean roughness (Ra) of the coating film is preferably 0.1 μm or more, more preferably 0.3 μm or more. Also, the arithmetic mean roughness (Ra) of the coating film is preferably 10.0 μm or less, more preferably 5.0 μm or less, and still more preferably 3.0 μm or less.
When it is at least the above lower limit, part of the particles appear on the surface of the coating film, so that the contact area is reduced when touched with a finger, and a smooth touch can be obtained. In addition, when the content is equal to or less than the above upper limit, it is possible to suppress rough touch when the coating film is touched with a finger.
In addition, the arithmetic mean roughness (Ra) is obtained by using the same coating film as the coating film used for measuring the Martens hardness described above, and using a surface roughness measuring machine by a method in accordance with JIS B0633: 2001. A stylus of 2 μm is used, and the measurement is performed under conditions of a moving speed of 0.5 mm/s, 23° C., and a relative humidity of 50%.

In this embodiment, the 85° gloss value of the coating film is preferably 3 or more, more preferably 5 or more. The 85° gloss value of the coating film is preferably 90 or less, more preferably 80 or less.
The 85° gloss value decreases as the unevenness of the coating surface increases, while the 85° gloss value increases as the coating surface becomes flat. By setting the 85° gloss value to be equal to or higher than the above lower limit, the surface of the coating film becomes flat, the contact area of the finger becomes large, and it is possible to suppress the feeling of tightness. By setting the 85° gloss value to be equal to or less than the above upper limit value, it is possible to prevent the uneven shape from becoming large and giving a rough feel to the touch.
The 85° gloss value is measured using the same coating film as the coating film used for measuring the Martens hardness described above under the conditions of 23 ° C. and 50% relative humidity by a method based on JIS Z8741: 1997. .

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can be adopted. Moreover, the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

Embodiments of the present invention will be described in detail based on examples and comparative examples. In addition, the present invention is not limited to the examples.

<Synthesis Example 1>
A flask equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet tube was charged with 80 parts by mass of methyl isobutyl ketone and heated to 115°C.
Separately, 36 parts by mass of methyl methacrylate (MMA), 18 parts by mass of butyl acrylate (BA), 10 parts by mass of 2-hydroxyethyl methacrylate (HEMA), and 30 parts by mass of polycaprolactone-modified hydroxyethyl acrylate (PLAXEL FA5 manufactured by Daicel Corporation) Part by mass, methacrylic acid (MAA) 1 part by mass, one-end methacrylate-modified polydimethylsiloxane (manufactured by JNC Co., Ltd., Silaplane FM-0721) 5 parts by mass, methyl isobutyl ketone 10 parts by mass, and 1,1'-azobis- A mixed solution (monomer solution) of 2 parts by mass of cyclohexane-1-carbonitrile (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., V-40) was prepared. This monomer solution was added dropwise to the flask over 2 hours, maintained at a temperature of 115° C., reacted for 3 hours while stirring, stopped heating and cooled to room temperature, and the resin solution containing (meth)acrylic resin ( solid content: 50% by mass). The obtained (meth)acrylic resin had a number average molecular weight (Mn) of 5,800 and a weight average molecular weight (Mw) of 20,000.

The hydroxyl value and weight average molecular weight (Mw) of the (meth)acrylic resin obtained in Synthesis Example 1 and the glass transition temperature (° C.) calculated from the compounding ratio of the monomers used based on the aforementioned Fox formula. was as shown in Table 1 below.

<Synthesis Examples 2 to 6>
Monomers were prepared according to the compounding ratio (numbers are parts by mass) shown in Table 1 below, and a resin solution containing various (meth)acrylic resins (solid content: 50 mass) was prepared in the same manner as in Synthesis Example 1. %) was obtained. The hydroxyl value, weight average molecular weight (Mw) and glass transition temperature (calculated value) of each resin were as shown in Table 1 below.

In Table 1, Plaxel FA5, Silaplane FM-0711, Silaplane FM-0721, and Silaplane FM-0725 are the following monomers. As for other monomers, commercially available products were appropriately used.
Praxel FA5: manufactured by Daicel Corporation, polycaprolactone-modified hydroxyethyl acrylate (caprolactone 5 mol adduct, molecular weight 689, hydroxyl value 74-84 mgKOH/g)
Silaplane FM-0711: manufactured by JNC Corporation, one end methacrylate-modified polydimethylsiloxane (number average molecular weight (Mn): 1000)
Silaplane FM-0721: manufactured by JNC Corporation, one end methacrylate-modified polydimethylsiloxane (number average molecular weight (Mn): 5000)
Silaplane FM-0725: manufactured by JNC Corporation, one end methacrylate-modified polydimethylsiloxane (number average molecular weight (Mn): 10000)

Here, the hydroxyl value, number average molecular weight (Mn), weight average molecular weight (Mw) and glass transition temperature of each (meth)acrylic resin obtained were obtained by the following methods.

<Hydroxyl value>
JIS K 0070 "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products", measured according to the method specified in "7.1 Neutralization titration method" and calculated.
Incidentally, when calculating the hydroxyl value, the value of the acid value is also required. The acid value was also measured and calculated according to the method specified in "3.1 Neutralization titration method" of the same JIS standard.

<Number average molecular weight, weight average molecular weight>
It was measured and calculated by gel permeation chromatography (GPC). The apparatus, conditions, etc. used are as follows.
Equipment used: HLC8220GPC (manufactured by Tosoh Corporation)
Columns used: TSKgel SuperHZM-M, TSKgel GMHXL-H, TSKgel G2500HXL, TSKgel G5000HXL (manufactured by Tosoh Corporation)
Column temperature: 40°C
Standard material: TSKgel standard polystyrene A1000, A2500, A5000, F1, F2, F4, F10 (manufactured by Tosoh Corporation)
Detector: RI (differential refraction) detector Eluent: Tetrahydrofuran Flow rate: 1 ml/min

<Glass transition temperature of (meth)acrylic resin>
The glass transition temperature of the (meth)acrylic resin was calculated based on the following Fox formula according to the compounding ratio of the monomers used.
1/Tg=( _W1 / _Tg1 )+( _W2 / _Tg2 )+( _W3 / _Tg3 )+...+( _Wn / _Tgn )
[Wherein, _Tg is _{the glass transition temperature (K) of the (meth)acrylic resin to be obtained, W 1 , W 2 , W 3 . 3} . . . Tg _n indicates the glass transition temperature (K) of a homopolymer composed of monomers corresponding to the mass fraction of each monomer. ]
The glass transition temperatures of Silaplane FM-0711, Silaplane FM-0721, and Silaplane FM-0725 shown in Table 1 were not considered because the glass transition temperatures were unknown. Glass transition temperatures were determined using only the monomers.

<Examples 1 to 17, Comparative Examples 1 to 15>
Synthesis Examples 1 to 6 obtained above and other materials (polyol, polyisocyanate compound, silicone additive, particles) shown in Tables 2 to 4 were mixed in amounts (unit: parts by mass) shown in each table. . Then, the solid content concentration was adjusted with butyl acetate to prepare a coating composition having a solid content of 30% by mass.
In each table, the amount of (meth)acrylic resin represents the amount of the resin (solid content) contained in the resin solution, not the amount of the resin solution (solid content: 50% by mass). In addition, in each table, the amounts of materials (polyols, polyisocyanate compounds, silicone additives, particles) other than (meth)acrylic resins also indicate the amount of solid content in each material.

Among the compounds in each table, information about the compounds other than the (meth)acrylic resin is as follows.

(polyol)
Polycaprolactone diol: Plaxel 208 manufactured by Daicel Corporation (molecular weight 830, hydroxyl value 130 to 140 mgKOH/g)
Polycaprolactone triol: Plaxel 308 manufactured by Daicel Corporation (molecular weight 850, hydroxyl value 190 to 200 mgKOH/g)
Polycaprolactone tetraol: Plaxel 410D manufactured by Daicel Corporation (molecular weight 1000, hydroxyl value 216-232 mgKOH/g)
Carbonate diol: Duranol T5652 manufactured by Asahi Kasei Corporation (molecular weight 2000, hydroxyl value 51-61 mgKOH/g)

(Hardening agent: polyisocyanate compound)
Duranate TPA-100: Asahi Kasei Corporation, isocyanurate type of hexamethylene diisocyanate (isocyanate group content: 23% by mass, solid content: 100% by mass)

(silicone additive)
BYK-370: manufactured by BYK-Chemie Japan Co., Ltd., hydroxyl group-containing polyether-modified polydimethylsiloxane solution (solid content 20% by mass)

(particle)
MEK-ST-40: manufactured by Nissan Chemical Co., Ltd., methyl ethyl ketone dispersion solution of nanosilica particles (40% by mass of silica particles), average particle size: 12 nm
Nip Seal E-1011: manufactured by Tosoh Silica Co., Ltd., silica particles, average particle size: 1.5 μm
Silysia 435: manufactured by Fuji Silysia Chemical Co., Ltd., silica particles, average particle size: 2.5 μm
Artpearl GR-800: manufactured by Negami Industrial Co., Ltd., acrylic particles, average particle size: 6 μm
Artpearl GR-400: manufactured by Negami Industrial Co., Ltd., acrylic particles, average particle size: 15 μm
Artpearl GR-200: manufactured by Negami Industrial Co., Ltd., acrylic particles, average particle size: 32 μm
Artpearl JB-800T: manufactured by Negami Industrial Co., Ltd., urethane particles, average particle size: 6 μm
Artpearl C-400: manufactured by Negami Kogyo Co., Ltd., urethane particles, average particle size: 15 μm
Artpearl C-100: manufactured by Negami Industrial Co., Ltd., urethane particles, average particle size: 50 μm
Techpolymer ACP-8C: Sekisui Plastics Co., Ltd., crosslinked polyacrylic acid particles, average particle size: 8 μm
Techpolymer ARX-30: Sekisui Plastics Co., Ltd., crosslinked polyacrylic acid particles, average particle size: 30 μm

<Average particle size (measured by the Coulter counter method)>
The average particle size of particles was measured by the following method using the following equipment, conditions, and the like.
(Equipment, conditions, etc. used for average particle size measurement)
- Measuring device: Precision particle size distribution measuring device (manufactured by Beckman Coulter, "Coulter Counter Multisizer 3")
・ Dedicated software attached to the device: "Beckman Coulter Multisizer 3 Version 3.51" manufactured by Beckman Coulter
・Electrolytic aqueous solution: "ISOTON II" manufactured by Beckman Coulter
- Aperture size: The following two types were used depending on the average particle size of the particles to be measured.
(When the average particle size is 1.5 μm, 2.5 μm) 20 μm
(When the average particle size is 6.0 μm, 8.0 μm, 15 μm, 30 μm, 32 μm, 50 μm) 100 μm
(Average particle size measurement method)
1. About 200 mL of the electrolytic aqueous solution was placed in a 250 mL round-bottom glass beaker exclusively for the precision particle size distribution measuring device, set on a sample stand, and stirred with a stirrer rod. Then, dirt and air bubbles inside the aperture tube were removed in advance by the "flush aperture tube" function of the dedicated software attached to the apparatus.
19 g of methanol and 1 g of the particles to be measured were added to a 2.50 mL beaker and dispersed at 28 kHz for 2 minutes using an ultrasonic cleaner (VS-100III manufactured by AS ONE) to obtain a sample to be measured.
3.1. 2. using a pipette into a round-bottomed beaker of 2. The measurement sample prepared in 1) was dropped little by little, and the measurement concentration was adjusted to a concentration at which approximately 10000 samples were counted in 10 seconds. The measurement was continued until the number of measured particles reached 50,000. The measured concentration was appropriately adjusted according to the volume average particle size of the particles to be measured. For example, when the volume average particle size is 1.5 μm, it is about 1%, and when the volume average particle size is 8.0 μm, it is about 4%. In addition, the above aperture diameter was used for the measurement according to the volume average particle diameter of the particles.
4.3. The measurement data obtained in , was analyzed using the dedicated software attached to the device, and the volume average particle size was calculated (by taking the average value of the particle size distribution based on the volume of the measured particle size, the volume average particle size diameter can be calculated).

<Average particle size (measured with a transmission electron microscope)>
Regarding the average particle size of MEK-ST-40, the particles were fine and below the lower measurement limit of the method described in <Average particle size (measured by Coulter counter method)>, so it was measured by the following method. .
First, a sample obtained by diluting particles with methanol to a concentration of 0.1% by mass was subjected to dispersion treatment for 1 minute using an ultrasonic disperser to obtain a dispersion liquid. The obtained dispersion liquid was dropped onto the sample stage of the microscope used for the measurement, and the methanol was dried under normal temperature and normal pressure. After drying, the particles were subjected to a sputtering process to coat the particle surfaces with gold of about 10 nm, which was used as a sample for observation.
Using a transmission electron microscope, particles of the obtained sample were observed and images were taken at an accelerating voltage of 200 kV and an appropriate magnification. The equivalent circle diameters of 500 particles judged to be primary particles (particles that are not agglomerated) were measured from the photographed image, and the average value was taken as the number average particle diameter.

<Preparation of coating film for evaluation>
Using each coating composition prepared in Examples and Comparative Examples, coating films for evaluation were formed as follows. First, each coating composition is applied to an ABS (acrylonitrile, butadiene, styrene copolymer synthetic resin) substrate (manufactured by TP Giken Co., Ltd., compliant with JIS K6873) with an air spray, and then the coated substrate is set to 80 ° C. Heated in a safe oven for 60 minutes. After heating, the substrate was allowed to stand in an atmosphere of 25° C. and a relative humidity of 50% for 4 weeks to obtain a substrate having a 20 μm-thick film for evaluation. Using the coating film for evaluation thus obtained, the following various physical property tests (other than <the glass transition temperature of the coating composition for measuring the glass transition temperature in which particles are removed from the coating composition> described later) were performed. The results of various physical property tests are shown in Tables 2 to 4 below.

<Martens hardness>
Using the evaluation coating film (with substrate) obtained in <Preparation of coating film for evaluation>, the Martens hardness was measured by the following method in an atmosphere of 23 ° C. and 50% relative humidity. . Specifically, a Vickers indenter (square Measurements were made by indenting a weighted diamond indenter for 20 seconds. Note that the measurement was performed with care so that the indentation depth of the indenter was less than 20 μm (so that the indenter did not reach the substrate).
Martens hardness was calculated by the following formula.
Martens hardness (N/mm ² )=Fmax/(26.43×(Hmax) ² )
Fmax: Maximum test force Hmax: Indentation depth at Fmax

<Friction coefficient>
The static friction coefficient (μS) and average dynamic friction coefficient (μK) were measured using the evaluation coating film (with substrate) obtained in <Preparation of coating film for evaluation>.
Specifically, in an atmosphere of 23 ° C. and 50% relative humidity, the evaluation coating film (with substrate) is set in a static/dynamic friction measuring device (TL201Tt, manufactured by Trinity Lab Co., Ltd.), and the attached film is attached to the measuring device. A tactile contact (contact having hardness equivalent to a fingertip: contact area 1.5 cm ² ) is brought into contact with the evaluation coating film, and the contact is moved 30 mm at a speed of 30 mm / s while applying a load of 10 g. Thus, static friction coefficient (μS) and average dynamic friction coefficient (μK) were measured.
The maximum value measured in the range of the moving distance of the tactile contact from 0 to less than 10 mm is the coefficient of static friction (μS) (the largest resistance observed immediately after sliding), and the moving distance of the tactile contact is 10 to 25 mm. The average dynamic friction coefficient (μK) (the resistance in the stable region after the start of sliding) was obtained by calculating the average value of the measured values in the range of .
From the values of the static friction coefficient (μS) and the average dynamic friction coefficient (μK) obtained, the sum of the static friction coefficient and the average dynamic friction coefficient (μS+μK) was calculated.

<Arithmetic mean roughness (Ra)>
Using the evaluation coating film (with substrate) obtained in <Preparation of coating film for evaluation>, JIS B0633: 2001 (geometric characteristics specification of product (GPS) - surface texture: contour curve method - evaluation of surface texture method and procedure), 23 ° C., in an atmosphere of 50% relative humidity, using a surface roughness measuring machine (manufactured by Kosaka Laboratory Co., Ltd., SE300) to measure the arithmetic mean roughness (Ra). rice field. A stylus with a tip radius of 2 μm was used, and the measurement was performed at a moving speed of 0.5 mm/s.

<85° gloss value>
Using the evaluation coating film (with substrate) obtained in <Preparation of coating film for evaluation>, in an atmosphere of 23 ° C. and 50% relative humidity, a gloss meter ( BYK Gardner, micro-gloss) was used to measure the 85° gloss value.

<Glass transition temperature of coating composition for glass transition temperature measurement excluding particles from coating composition>
The constituent materials excluding the particles of the various coating compositions shown in Tables 2 to 4 below, that is, the (meth)acrylic resins, polyols, polyisocyanate compounds, and silicone additives obtained in Synthesis Examples 1 to 6 were used. were used to prepare coating compositions for measuring the glass transition temperature in the same manner as described in <Examples 1 to 17, Comparative Examples 1 to 15>. Using the obtained coating composition for measuring glass transition temperature, a coating film for measuring glass transition temperature was formed as follows.
First, each coating composition for measuring the glass transition temperature was applied to a polypropylene substrate (manufactured by TP Giken Co., Ltd., compliant with JISK6921) by air spray, and then the coated substrate was placed in a safe oven set at 80 ° C. Heated for 60 minutes. After heating, the substrate was allowed to stand in an atmosphere of 25° C. and a relative humidity of 50% for 4 weeks to obtain a substrate with a coating film having a thickness of 50 μm.
The coating film was peeled off from the substrate, and further cut into strips of 5 mm in width and 50 mm in length, which were used as test pieces for measurement. Using this test piece, dynamic viscoelasticity measurement was performed under the following conditions in an atmosphere of 23° C. and 50% relative humidity. The maximum value tan δmax of the loss tangent obtained from this measurement was taken as the glass transition temperature (° C.) of the coating composition for glass transition temperature measurement in which the particles were removed from the coating composition. The results are shown in Tables 2-4 below.
Device: dynamic viscoelasticity measuring device RSA3 (manufactured by TA Instruments)
Measurement mode: Non-resonant forced vibration method Heating rate: 5.0°C/min
Measurement interval: 12/min
Frequency: 1.0Hz
Temperature range: -50 to 180°C

<Tactile evaluation>
Using the evaluation coating film (with substrate) obtained in <Preparation of coating film for evaluation>, 20 monitors (10 adult men and 10 adult women) were tested in an atmosphere of 23 ° C. and 50% relative humidity. Below, the coating film was touched with a finger and scored based on the following evaluation criteria (relative evaluation), and the average value was used as the evaluation score. The results are shown in Tables 2-4 below.
(Evaluation criteria)
[Hardness of coating film]
1: Feels hard 2: Feels rather hard 3: Neither can be said 4: Feels rather soft 5: Feels soft
[Strong feeling]
1: There is a tight feeling.
2: If anything, there is a tight feeling.
3: Neither can be said.
4: If anything, there is no stiff feeling.
5: No stiff feeling.
[Smooth touch]
1: Not smooth.
2: Rather not smooth.
3: Neither can be said.
4: Rather smooth.
5: Smooth.
[Touch]
1: Poor touch feeling.
2: If anything, the touch feeling is bad.
3: Neither can be said.
4: Fairly comfortable to touch.
5: Comfortable to touch.

<Paint film appearance evaluation (slimy feeling)>
Using the evaluation coating film (with substrate) obtained in <Preparation of coating film for evaluation>, 20 monitors (10 adult men and 10 adult women) were tested in an atmosphere of 23 ° C. and 50% relative humidity. Below, the appearance of the coating film was visually and tactilely evaluated, and evaluated based on the following evaluation criteria. The results are shown in Tables 2-4 below.
(Evaluation criteria)
○: There is no slimy feeling in the coating film appearance ×: There is a slimy feeling in the coating film appearance

Consideration of Examples 1 to 6 and Comparative Examples 1 to 5 In Table 2, a (meth)acrylic resin having a polysiloxane skeleton and a coating composition containing particles having an average particle diameter of 1.0 μm or more and 100.0 μm or less are μS + μK was good, and a smooth touch was obtained when the coating film was touched (Examples 1 to 6). In addition, it was found that the smaller the average particle diameter of the particles, the smoother the touch feeling when touching the coating film, and the better the touch (Examples 1, 2, 5 and 6).
On the other hand, the coating compositions that did not contain a (meth)acrylic resin having a polysiloxane skeleton did not have a favorable μS + μK value, and were inferior in smooth touch to those of Examples 1 to 6 (Comparative Examples 1, 2, 5 ). Among them, in Comparative Example 2, a slimy feeling occurred and a suitable coating film could not be obtained (In addition, in Example 1 and Comparative Example 2, the content of the structural unit having a polysiloxane skeleton contained in the coating composition was are identical). In addition, even in the coating composition containing no particles or having an average particle size of less than 1.0 μm, the μS + μK value was not good, and the smooth touch was inferior to that of Examples 1 to 6 (comparative Examples 3, 4).

Consideration of Examples 7 to 14 and Comparative Examples 6 to 10 In Table 3, a (meth)acrylic resin having a polysiloxane skeleton and a coating composition containing particles having an average particle diameter of 1.0 μm or more and 100.0 μm or less are μS + μK was good, and a smooth touch was obtained when the coating film was touched (Examples 7 to 14).
On the other hand, the coating composition containing no (meth)acrylic resin having a polysiloxane skeleton did not have a good value of µS + µK, and was inferior in smooth touch to Examples 7 to 14 (Comparative Examples 6, 7, 10 ). Among them, in Comparative Example 7, a slimy feeling occurred and a suitable coating film could not be obtained (In addition, in Example 7 and Comparative Example 7, the content of the structural unit having a polysiloxane skeleton contained in the coating composition was are identical). In addition, even in the coating composition containing no particles or having an average particle size of less than 1.0 μm, the μS + μK value was not good, and the smooth touch was inferior to that of Examples 7 to 14 (comparative Examples 8, 9).

Consideration of Examples 15 to 17 and Comparative Examples 11 to 15 In Table 4, a (meth)acrylic resin having a polysiloxane skeleton and a coating composition containing particles having an average particle size of 1.0 μm or more and 100.0 μm or less are μS + μK was good, and a smooth touch was obtained when the coating film was touched (Examples 15 to 17).
On the other hand, the coating composition that does not contain a (meth)acrylic resin having a polysiloxane skeleton did not have a good μS+μK value, and was inferior to Examples 15 to 17 in smooth touch (Comparative Examples 11, 12 and 15 ). Among them, in Comparative Example 12, a slimy feeling occurred and a suitable coating film could not be obtained (In addition, in Example 15 and Comparative Example 12, the content of the structural unit having a polysiloxane skeleton contained in the coating composition was are identical). In addition, even in the coating composition containing no particles or having an average particle size of less than 1.0 μm, the μS + μK value was not good, and the smooth touch was inferior to that of Examples 15 to 17 (comparative Examples 13 and 14).

Claims (12)

a (meth)acrylic resin having a hydroxy group;
a polyisocyanate compound;
and particles having an average particle diameter of 1.0 μm or more and 100.0 μm or less,
The (meth)acrylic resin is a coating composition having a polysiloxane skeleton. A coating composition according to claim 1,
A coating composition having a Martens hardness of 1 N/mm ² or more and 200 N/mm ^{2 or} less, measured under [Martens hardness measurement conditions] below, of a coating film formed under the conditions described in [Coating film formation conditions] below. .
[Coating film formation conditions]
The coating composition is applied onto an acrylonitrile/butadiene/styrene copolymer synthetic resin substrate by air spray, the coated substrate is heated at 80°C for 60 minutes, and after heating, it is heated at 25°C under conditions of 50% relative humidity. A coating film having a film thickness of 20 μm is obtained by allowing to stand for 4 weeks.
[Martens hardness measurement conditions]
Using the coating film formed under the above [coating film forming conditions], a load of 4 mN was applied to the coating film using a microhardness tester under conditions of 23 ° C. and a relative humidity of 50%. Martens hardness is measured by indenting a Vickers indenter for 20 seconds. The Martens hardness is calculated by the following formula, where Fmax is the maximum test force and Hmax is the indentation depth by Fmax.
Martens hardness (N/mm ² )=Fmax/(26.43×(Hmax) ² ) A coating composition according to claim 2,
When the static friction coefficient measured under the conditions described in the following [Friction coefficient measurement conditions] of the coating film formed under the conditions described in [Coating film formation conditions] is μS, and the average dynamic friction coefficient is μK, the Martens hardness a value of μS+μK of 1.8 or less when the Martens hardness is 30 N/mm ² or less, and a value of μS+μK of 1.4 or less when the Martens hardness is greater than 30 N/mm ² .
[Friction coefficient measurement conditions]
Using the coating film formed in the [coating film forming conditions], the coating film is applied to a static/dynamic friction coefficient measuring machine (TL201Tt, manufactured by Trinity Lab Co., Ltd.) under conditions of 23 ° C. and a relative humidity of 50%. Attached, the tactile contact attached to the measuring machine is brought into contact with the coating film at a contact area of 1.5 cm ² , and the tactile contact is applied at a speed of 30 mm / s while applying a load of 10 g. Static friction coefficient (μS) and average dynamic friction coefficient (μK) are measured by moving 30 mm. The static friction coefficient (μS) is the maximum value of the friction coefficient measured in the range of 0 mm or more and less than 10 mm of the tactile contact, and the measured value of the friction coefficient measured in the range of 10 mm or more and 25 mm or less of the tactile contact. Let the average value of the average dynamic friction coefficient (μK). The coating composition according to any one of claims 1 to 3,
The glass transition temperature (° C.) of the coating composition for measuring the glass transition temperature, which is obtained by removing the particles from the coating composition, measured under the conditions described in [Conditions for measuring the glass transition temperature] below is −30° C. or more and 90° C. A coating composition that is:
[Glass transition temperature measurement conditions]
The coating composition for measuring the glass transition temperature was applied to a polypropylene substrate by air spray, and the coated substrate was heated at 80°C for 60 minutes. A coating film having a film thickness of 50 μm is obtained by placing. The coating film is peeled off from the substrate and cut into pieces having a width of 5 mm and a length of 50 mm to obtain test pieces. Using the test piece, under the conditions of 23 ° C. and 50% relative humidity, the maximum value tan δmax of the loss tangent when dynamic viscoelasticity is measured at a frequency of 1.0 Hz and a temperature in the range of -50 to 180 ° C. is measured. Transition temperature (°C). The coating composition according to any one of claims 1 to 4,
The arithmetic average roughness (Ra) of the coating film formed under the conditions described in [Coating film formation conditions] below, measured by [Method for measuring arithmetic average roughness], is 0.1 μm or more and 10.0 μm or less. paint composition.
[Coating film formation conditions]
The coating composition is applied onto an acrylonitrile/butadiene/styrene copolymer synthetic resin substrate by air spray, the coated substrate is heated at 80°C for 60 minutes, and after heating, it is heated at 25°C under conditions of 50% relative humidity. A coating film having a film thickness of 20 μm is obtained by allowing to stand for 4 weeks.
[Arithmetic mean roughness measurement method]
Using the coating film formed under the above [coating film forming conditions], a stylus with a radius of 2 μm was used with a surface roughness tester in accordance with JIS B0633:2001, and the moving speed was 0.00. Arithmetic mean roughness (Ra) is measured under conditions of 5 mm/s, 23° C., and relative humidity of 50%. The coating composition according to any one of claims 1 to 5,
The 85 ° gloss value of the coating film formed under the conditions described in [Coating film formation conditions] below, measured by a method in accordance with JIS Z8741: 1997 under the conditions of 23 ° C. and a relative humidity of 50% is 3 or more and 90 A coating composition that is:
[Coating film formation conditions]
The coating composition is applied onto an acrylonitrile/butadiene/styrene copolymer synthetic resin substrate by air spray, the coated substrate is heated at 80°C for 60 minutes, and after heating, it is heated at 25°C under conditions of 50% relative humidity. A coating film having a film thickness of 20 μm is obtained by allowing to stand for 4 weeks. The coating composition according to any one of claims 1 to 6,
The coating composition, wherein the content of the (meth)acrylic resin is 1% by mass or more and 80% by mass or less with respect to 100% by mass of the total solid content of the coating composition. The coating composition according to any one of claims 1 to 7,
The coating composition, wherein the content of the structural unit having the polysiloxane skeleton is 0.1% by mass or more and 20% by mass or less with respect to 100% by mass of the total solid content of the coating composition. The coating composition according to any one of claims 1 to 8,
A coating composition further comprising a polyol. A coating composition according to claim 9,
A coating composition, wherein the polyol comprises a carbonate diol. The coating composition according to any one of claims 1 to 10,
A coating composition, wherein the particles are one or more selected from silica particles, acrylic particles, urethane particles, and crosslinked polyacrylic acid particles. The coating composition according to any one of claims 1 to 11,
A coating composition, wherein the structural unit having a polysiloxane skeleton in the (meth)acrylic resin has a number average molecular weight (Mn) of 500 or more and 20,000 or less.