WO2018008271A1

WO2018008271A1 - Coating material and coating film

Info

Publication number: WO2018008271A1
Application number: PCT/JP2017/019177
Authority: WO
Inventors: 隆磯貝
Original assignee: 藤倉化成株式会社
Priority date: 2016-07-05
Filing date: 2017-05-23
Publication date: 2018-01-11
Also published as: TWI638868B; TW201811932A; JP2018002927A

Abstract

The coating material of the present invention comprises an acrylic copolymer having alkoxysilyl groups, a dimethylpolysiloxane having hydroxy groups at both terminals, and a metal catalyst, the contents of the dimethylpolysiloxane and the metal catalyst being 0.5 parts by mass or more and 1.0 parts by mass or more, respectively, per 100 parts by mass of the acrylic copolymer. The coating film of the present invention is obtained by heating the coating material at 60-250ºC for 30 seconds to 60 minutes.

Description

Paints and coatings

The present invention relates to a paint and a coating film.
This application claims priority based on Japanese Patent Application No. 2016-133448 filed in Japan on July 5, 2016, the contents of which are incorporated herein by reference.

In various types of base materials, the surface of the base material is often painted for the purpose of protecting the surface or imparting design properties. In addition, in order to prevent dirt from adhering to the coating film formed on the surface of the substrate, a coating that can impart water repellency to the coating (hereinafter also referred to as “water-repellent coating”) has been proposed.
As such a paint, a paint mainly composed of a silicone resin skeleton or a fluorine-based resin is generally used. For example, Patent Document 1 discloses an organopolysiloxane having two or more silanol groups in one molecule, an organosilane having two or more hydrolyzable groups in one molecule, or a partially hydrolyzed condensate thereof, and metal curing. An antifouling paint composition containing a catalyst, an oxide of copper or zinc, and an alcohol is disclosed.

Japanese Unexamined Patent Publication No. 2016-20430

In order to form a water-repellent coating film on the substrate surface, a water-repellent coating is applied to the substrate surface and then heat-treated at a high temperature (eg, about 130 ° C.). By performing the heat treatment at a high temperature, the water-repellent paint on the substrate surface is cured to form a coating film, and the coating film exhibits water repellency. Thus, heat treatment at a high temperature is required to make the coating film exhibit water repellency.

However, for example, when the base material is made of a thermoplastic resin, it is difficult to heat-treat at a high temperature because the base material is easily deformed when heat-treated at a high temperature. On the other hand, when the heat treatment is performed at a temperature at which the base material is not deformed, the treatment temperature is too low and sufficient water repellency is hardly exhibited. Therefore, the conventional water-repellent paint is not suitable for a thermoplastic resin base material.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paint capable of forming a coating film excellent in water repellency even when heat-treated at a low temperature, and a coating film excellent in water repellency.

The present invention has the following aspects.
[1] An acrylic copolymer having an alkoxysilyl group, a dimethylpolysiloxane having hydroxy groups at both ends, and a metal catalyst, and the dimethylpolysiloxane with respect to 100 parts by mass of the acrylic copolymer. The coating material whose content of a siloxane is 0.5 mass part or more and whose content of the said metal catalyst is 1.0 mass part or more.
[2] A coating film obtained by heat-treating the paint according to [1] at 60 to 250 ° C. for 30 seconds to 60 minutes.

According to the coating material of the present invention, a coating film having excellent water repellency can be formed even by heat treatment at a low temperature.
Moreover, the coating film of this invention is excellent in water repellency.

Hereinafter, the present invention will be described in detail.
In the present invention, the “acrylic copolymer” is a copolymer having a structural unit (monomer unit) based on an acrylic monomer. An acrylic monomer refers to a monomer having a (meth) acryloyl group. “(Meth) acryloyl group” is a general term for an acryloyl group and a methacryloyl group.
The “alkoxysilyl group” is a group in which 1 to 3 alkoxy groups are directly bonded to a silicon atom.
“(Meth) acrylic acid” is a general term for acrylic acid and methacrylic acid.
In the following description, “low temperature” refers to a temperature at which the base material is not easily deformed when the paint of the present invention is applied to a base material made of, for example, a thermoplastic resin and heat-treated.
“Normal temperature” is a temperature defined by JIS Z 8703, that is, 5 to 35 ° C.

"paint"
The paint of the present invention comprises an acrylic copolymer having an alkoxysilyl group (hereinafter also referred to as “(A) component”) and a dimethylpolysiloxane having a hydroxy group at both ends (hereinafter referred to as “(B) component”). And a metal catalyst (hereinafter also referred to as “component (C)”).

<(A) component>
The component (A) is an acrylic copolymer having an alkoxysilyl group.
The component (A) can be obtained by copolymerizing an acrylic monomer and a monomer having an alkoxysilyl group. That is, the component (A) is a reaction product of a monomer mixture containing an acrylic monomer and a monomer having an alkoxysilyl group, and is a unit derived from an acrylic monomer (acrylic monomer) Body unit) and a unit derived from a monomer having an alkoxysilyl group (a monomer unit having an alkoxysilyl group).

The acrylic monomer mainly plays a role of imparting good coating workability to the paint and adhesion performance to an object such as a base material.
Examples of acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, and n-butyl (meth) acrylate. (Meth) acrylic acid i-butyl, (meth) acrylic acid pentyl, (meth) acrylic acid hexyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid heptyl, (meth) acrylic acid octyl ( (Meth) acrylic acid alkyl ester; (meth) acrylic acid 2-methoxyethyl, (meth) acrylic acid 2-ethoxyethyl, (meth) acrylic acid 2- (n-propoxy) ethyl, (meth) acrylic acid 2- (n -Butoxy) ethyl, 3-methacrylpropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, (meth) acrylic acid -(N-propoxy) propyl, (meth) acrylic acid alkoxyalkyl esters such as 2- (n-butoxy) propyl (meth) acrylate; cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, ( Hydroxy group-containing (meth) acrylic acid ester such as (meth) acrylic acid ester such as isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate; Examples include (meth) acrylic acid. Any one of these acrylic monomers may be used alone, or two or more of them may be used in combination.

The monomer having an alkoxysilyl group serves as a silane coupling agent, and makes the component (A) a crosslinked structure, and causes the (A) component of the crosslinked structure to react with the component (B) described later. Specifically, the alkoxysilyl group in component (A) reacts with the hydroxy group in component (B).
The monomer having an alkoxysilyl group is preferably a monomer having a group represented by the following general formula (1).

In formula (1), ^{R 1} is an alkyl group having 1 to 4 carbon atoms, ^{R 2} is a hydrogen atom or an alkyl group having a carbon number of 1 ~ 10, m is an integer of 1-3.

R ¹ is an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group.
R ² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, more preferably methyl group.
m is an integer of 1 to 3, and an integer of 2 or 3 is preferable.

The monomer having a group represented by the general formula (1) is not particularly limited as long as it is copolymerizable with an acrylic monomer, but for example, a group represented by the general formula (1) In addition, monomers having a reactive functional group such as (meth) acryloyl group, vinyl group, epoxy group, aminopropyl group, mercapto group (thiol group) can be mentioned. Specifically, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane , Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (n-propoxy) silane, vinyltriisopropoxysilane, vinyltributoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxy Propylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-aminopropyltrimeth Xysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldiethoxysilane, N-2- ( Aminoethyl) -3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxy Examples thereof include silane, 3-mercaptopropyltrimethoxysilane, and allyltriethoxysilane. Moreover, said monomer may use any 1 type of these individually, and may use 2 or more types together.

In addition to the above, what is generally called a silane coupling agent can also be used as the monomer having an alkoxysilyl group.

The content of the acrylic monomer unit in the component (A) is preferably 5 to 95% by mass, more preferably 20 to 90% by mass with respect to the total mass of all the structural units constituting the component (A). 35 to 85% by mass is more preferable.
The content of the monomer unit having an alkoxysilyl group in the component (A) is preferably 5 to 95% by mass with respect to the total mass of all the structural units constituting the component (A), and 10 to 80% by mass. Is more preferable, and 15 to 65% by mass is even more preferable.
If the content of the acrylic monomer unit is 5% by mass or more and the content of the monomer unit having an alkoxysilyl group is 95% by mass or less, the oil repellency is excellent in addition to the water repellency. A coating film is obtained. In addition, since the component (A) is easily compatible with the component (B) described later, the coating film can be prevented from becoming cloudy.
If the content of the acrylic monomer unit is 95% by mass or less and the content of the monomer unit having an alkoxysilyl group is 5% by mass or more, the oil repellency is excellent in addition to the water repellency. A coating film is obtained. In particular, when the content of the acrylic monomer unit is 90% by mass or less and the content of the monomer unit having an alkoxysilyl group is 10% by mass or more, the oil repellency and oil repellency of the coating film are further improved. improves.

As long as the component (A) is within the range not impairing the effects of the present invention, an acrylic monomer and a monomer having an alkoxysilyl group were copolymerized with another monomer as necessary. It may be a thing.
The other monomer is not particularly limited as long as it is copolymerizable with an acrylic monomer and a monomer having an alkoxysilyl group. For example, maleic acid, phthalic acid, itaconic acid, vinyl acetate, styrene, etc. Is mentioned.
The content of units derived from other monomers (other monomer units) is preferably 20% by mass or less, and preferably 10% by mass or less, based on the total mass of all the structural units constituting the component (A). Is more preferable, and 5 mass% or less is still more preferable.

The weight average molecular weight of the component (A) is preferably 5000 to 150,000, more preferably 8000 to 100,000, and still more preferably 10,000 to 50,000. If the mass average molecular weight of (A) component is 5000 or more, an unreacted monomer will not remain easily. On the other hand, if the mass average molecular weight of the component (A) is 150,000 or less, stringing during coating can be suppressed. Moreover, the smoothness of the coating film obtained can be maintained favorably.
The weight average molecular weight of the component (A) is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

The content of silicon in the component (A) (hereinafter also referred to as “Si ratio”) is preferably 1 to 10% by mass, more preferably 1.5 to 9% by mass with respect to the total mass of the component (A). preferable. When the Si ratio is 1% by mass or more, the reaction between the component (A) and the component (B) sufficiently proceeds, the water repellency of the coating film is further increased, and the strength of the coating film is also increased. In addition, the coating film easily exhibits oil repellency. On the other hand, if the Si ratio is 10% by mass or less, the component (A) is easily compatible with the later-described component (B), so that the coating film can be prevented from becoming cloudy.
(A) Content of Si in a component is a value measured using a thermogravimetry apparatus.

<(B) component>
Component (B) is dimethylpolysiloxane having hydroxy groups at both ends. That is, the component (B) is a dimethyl silicone oil having silanol groups at both ends.
The weight average molecular weight of the component (B) is preferably 20000 or less, more preferably 15000 or less, and even more preferably 10,000 or less. If the mass average molecular weight of (B) component is 20000 or less, water repellency will be easy to express. Moreover, since compatibility improves, it can suppress that a coating film becomes cloudy. In particular, when the mass average molecular weight of the component (B) is 15000 or less, a coating film having excellent oil repellency can be obtained. The lower limit of the weight average molecular weight of the component (B) is not particularly limited.
The weight average molecular weight of the component (B) is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

(B) Content of a component is 0.5 mass part or more with respect to 100 mass parts of (A) component, 0.6 mass part or more is preferable and 1 mass part or more is more preferable. If content of (B) component is 0.5 mass part or more, the coating film excellent in water repellency will be obtained.
(B) 100 mass parts or less are preferable with respect to 100 mass parts of (A) component, as for content of a component, 50 mass parts or less are more preferable, 30 mass parts or less are more preferable, and 10 mass parts or less are especially preferable. If content of (B) component is 100 mass parts or less with respect to 100 mass parts of (A) component, since compatibility with (A) component can be maintained favorable, it can suppress that a coating film becomes cloudy. . In particular, when the content of the component (B) is 10 parts by mass or less with respect to 100 parts by mass of the component (A), a coating film having excellent oil repellency can be obtained.

<(C) component>
Component (C) is a metal catalyst.
The component (C) mainly serves to promote the reaction between the alkoxysilyl group of the component (A) and the hydroxy group of the component (B).
Examples of the component (C) include metal alkoxides, metal chelates, and organic tin compounds.

Examples of the metal alkoxide include a compound represented by the following general formula (2).
M (OR ³ ) _n (2)

In formula (2), M is a metal element, R ³ is an alkyl group having 1 to 4 carbon atoms, and n is the oxidation number of the metal element.
Examples of the metal element (M) of the metal alkoxide include titanium, aluminum, zinc, zirconium, tin, and vanadium. Among these, titanium or aluminum is preferable because it is difficult to be colored and has excellent stability as a catalyst and reactivity when formed into a paint.
R ³ is an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 2 to 4 carbon atoms, and more preferably a propyl group or a butyl group.
When n is 2 or more, (OR ³ ) may be the same as or different from each other, but are preferably the same as each other.

Specific examples of the metal alkoxide include titanium tributoxide, titanium tributoxide dimer, and aluminum trisecondary butoxide. Any one of these metal alkoxides may be used alone, or two or more of them may be used in combination.

Examples of the metal chelate compound include aluminum chelates such as aluminum ethyl acetoacetate / diisopropylate, aluminum alkyl acetoacetate / diisopropylate, aluminum bisethylacetoacetate / monoacetylacetonate, acetoalkoxyaluminum diisopropylate; Isopropoxybis (acetylacetonate), titanium tetraacetylacetonate, titanium di-2-ethylhexoxybis (2-ethyl-3-hydroxyhexoxide), titanium diisopropoxybis (ethylacetoacetate), di- Examples thereof include titanate chelates such as i-propoxy bis (acetylacetonato) titanium and propanedioxytitanium bis (ethylacetoacetate). Any one of these metal chelate compounds may be used alone, or two or more of them may be used in combination.

Examples of the organic tin compound include dibutyltin dilaurate and dibutyltin dioctylate. Any one of these organic tin compounds may be used alone, or two or more thereof may be used in combination.

(C) Content of a component is 1.0 mass part or more with respect to 100 mass parts of (A) component, 1.5 mass parts or more are preferable and 2 mass parts or more are more preferable. If content of (C) component is 1.0 mass part or more with respect to 100 mass parts of (A) component, since a coating film fully hardens | cures, the outstanding water repellency can be expressed.
(C) Although it does not restrict | limit in particular about the upper limit of content of a component, 30 mass parts or less are preferable with respect to 100 mass parts of (A) component, 20 mass parts or less are more preferable, 10 mass parts or less are more preferable, 5 parts by mass or less is particularly preferable. In particular, if the content of the component (C) is 5 parts by mass or less with respect to 100 parts by mass of the component (A), the stability of the paint is increased, so that the usable time until the paint can be used after it is manufactured A paint with a long (pot life) can be obtained.

<Other ingredients>
The paint of the present invention may contain, for example, an additive or a solvent in addition to the above components, as long as the effects of the present invention are not impaired.
Examples of additives include pigments, fillers, plasticizers, surface conditioners, dispersants, coating surface preparation agents, surfactants, light stabilizers, antioxidants, thickeners, thixotropic agents, and antistatic agents. , Ultraviolet absorbers, and brighteners.
Examples of the solvent include water and organic solvents. Examples of the organic solvent include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; and ester solvents such as ethyl acetate and butyl acetate. .

<Manufacturing method>
The coating material of this invention is obtained by mixing (A) component, (B) component, and (C) component, and another component as needed.

<Effect>
Since the coating material of the present invention described above contains the above-described component (A), component (B), and (C), a coating film having excellent water repellency can be formed. The reason for this is considered as follows.
When the coating material of the present invention is applied to an object (substrate surface) and cured, the alkoxysilyl group in the component (A) and the hydroxy group in the component (B) are catalyzed by the component (C). To react. As a result, it is considered that the main chain of (B) is oriented in an inverted U shape on the surface of the coating film, so that the coating film exhibits water repellency.

Further, as described above, in the case of a conventional water-repellent paint, it is necessary to heat-treat at a high temperature (for example, about 130 ° C.) after being applied to an object, so that it is not suitable for a thermoplastic resin base material. It was.
However, if it is the coating material of this invention, water-repellent property will be expressed by the reaction of the alkoxy silyl group in (A) component, and the hydroxyl group in (B) component. The reaction between the alkoxysilyl group and the hydroxy group proceeds sufficiently even at a relatively low temperature in the presence of the component (C). Therefore, even when the paint of the present invention is heat-treated at a low temperature, a coating film having excellent water repellency can be formed. The reaction between the alkoxysilyl group and the hydroxy group proceeds even at room temperature in the presence of the component (C). Therefore, a coating film having excellent water repellency can be obtained even when the paint of the present invention is left at room temperature. Can be formed.
Therefore, even if the object is a base material that easily deforms when heated at a high temperature, for example, a base material made of a thermoplastic resin, the surface of the base material can be made water repellent by using the paint of the present invention. A coating film can be formed.

In particular, if the content of the component (B) in the coating is 10 parts by mass or less with respect to 100 parts by mass of the component (A), or if the mass average molecular weight of the component (B) is 15000 or less, the oil repellency In addition, an excellent coating film can be formed.

[Coating]
The coating film of the present invention is obtained, for example, by applying the above-described coating material of the present invention to the substrate surface and curing it.

Examples of the substrate include a plastic substrate, a metal substrate, and a glass substrate.
Examples of the plastic base material include polyester (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), polyolefin (eg, polyethylene, polypropylene, etc.), polyphenylene sulfide, polyamide (polyetherimide, polyimide amide, etc.), polycarbonate, acrylonitrile- Thermoplastic resins such as butadiene-styrene copolymer resin (ABS), acrylic resin, acrylonitrile-styrene copolymer resin, acrylic-styrene copolymer resin, polyvinyl chloride resin; phenol resin, epoxy resin, melamine resin, urethane resin, etc. And thermosetting resin. Among these, examples of the heat-resistant thermoplastic resin include polybutylene terephthalate, polyphenylene sulfide, polyamide (polyetherimide, polyimideamide, etc.), and polycarbonate.
Examples of the material for the metal substrate include aluminum, iron, nickel, chromium, titanium, copper, silver, zinc, tin, indium, magnesium, oxides thereof, and alloys thereof.

The shape of the substrate is not particularly limited, and may be either a film shape or a three-dimensional shape.
Moreover, from the viewpoint of improving the adhesion with the coating film, the substrate surface on which the coating film is formed may be subjected to pretreatment such as corona discharge treatment or plasma treatment.

The method for applying the coating material to the substrate is not particularly limited, and a known method can be adopted. For example, a spray coating method, a brush coating method, a roller coating method, a curtain coating method, a flow coating method, a dip coating method, etc. Is mentioned.

The curing temperature (heat treatment temperature) of the paint is determined according to the material of the substrate, but is usually from room temperature to 250 ° C. From the viewpoint of accelerating curing, it is preferable to heat-treat at 60 to 250 ° C. after applying the paint on the surface of the substrate (heat treatment step). Thus, since the fluidity | liquidity of a coating film reduces by a short time by hardening, it can suppress that a damage | wound, a foreign material, etc. adhere to a coating film. In particular, when the heat treatment temperature is 60 ° C. or higher, the reaction between the alkoxysilyl group in the component (A) and the hydroxy group in the component (B) proceeds sufficiently in a short time, and a coating film excellent in water repellency. can get. The higher the heat treatment temperature, the shorter the heat treatment time. In addition, by setting the heat treatment temperature to 60 ° C. or higher, the reaction between the alkoxysilyl group in the component (A) and the hydroxy group in the component (B) easily proceeds, and the water repellency of the coating film tends to increase. However, even if the heat treatment temperature exceeds 250 ° C., the ease of progress of the reaction reaches its peak. Further, if the heat treatment temperature is too high, the substrate may be deformed. If heat processing temperature is 250 degrees C or less, the alkoxysilyl group in (A) component and the hydroxy group in (B) component react in a short time, suppressing a deformation | transformation of a base material. The heat treatment temperature is preferably 200 ° C. or lower, more preferably 180 ° C. or lower, and further preferably 150 ° C. or lower.

When the substrate is made of a thermoplastic resin, the heat treatment temperature is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, and further preferably 80 ° C. or higher. About an upper limit, below the temperature which a base material cannot deform | transform easily (namely, below melting | fusing point of a thermoplastic resin) is preferable.
When the base material is made of a heat-resistant thermoplastic resin, thermosetting resin, metal, or glass, the heat treatment temperature is preferably 80 ° C or higher, more preferably 100 ° C or higher, and further preferably 120 ° C or higher. About an upper limit, 250 degrees C or less is preferable, 200 degrees C or less is more preferable, and 180 degrees C or less is further more preferable.

The heat treatment time is preferably 30 seconds to 60 minutes. When the heat treatment time is 30 seconds or longer, the reaction between the alkoxysilyl group in the component (A) and the hydroxy group in the component (B) sufficiently proceeds, and a coating film excellent in water repellency can be obtained. The longer the heat treatment time is, the more the reaction between the alkoxysilyl group in the component (A) and the hydroxy group in the component (B) proceeds, but the progress of the reaction reaches a peak even after 60 minutes. The heat treatment time is more preferably 15 to 60 minutes.

In addition, when heat processing temperature is low temperature (specifically 60 degreeC or more and less than 130 degreeC), after the heat processing process, it is preferable to leave (curing) the formed coating film at normal temperature for 3 days or more ( Neglect process). As described above, the higher the heat treatment temperature of the heat treatment step, the higher the water repellency of the coating film. However, even when the heat treatment is performed at a low temperature, by performing the leaving step after the heat treatment step, Water repellency is further improved. In addition, when the coating film exhibits oil repellency, the oil repellency tends to be improved.
Moreover, when hardening at normal temperature, after apply | coating a coating material to a base-material surface, it is preferable to leave (curing) for 7 days or more at normal temperature.

The film thickness of the coating film is preferably from 0.1 to 100 μm, more preferably from 1 to 50 μm.

Since the coating film of the present invention described above is obtained from the above-described coating film of the present invention, it is excellent in water repellency.
The reaction between the alkoxysilyl group in component (A) and the hydroxy group in component (B) described above varies depending on, for example, the heat treatment temperature and heat treatment time of the heat treatment step. It is difficult to specify the structure of the film. That is, in the present invention, there is a circumstance (impossible / impractical circumstance) that it is impossible or not practical to directly specify the coating film by its structure or characteristics.

Furthermore, the coating material of the present invention contains an acrylic copolymer having an alkoxysilyl group, dimethylpolysiloxane having a hydroxy group at both ends, and a metal catalyst, and is based on 100 parts by mass of the acrylic copolymer. In view of improving both water repellency and oil repellency, the content of the dimethylpolysiloxane is 0.5 parts by mass or more and 10 parts by mass or less, and the content of the metal catalyst is 2 parts by mass or more. To preferred.
The coating film of the present invention is obtained by heat-treating the coating material having the above composition at 60 to 250 ° C. for 30 seconds to 60 minutes, and then leaving it at 25 ° C. for 3 days or more, preferably 7 days. It is preferable from the viewpoint of improving both water repellency and oil repellency.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

“Production of acrylic copolymer (A)”
<Production of acrylic copolymer (A-1)>
In a three-necked reaction vessel, 75 parts by mass of methyl methacrylate, 25 parts by mass of n-butyl acrylate, 100 parts by mass of toluene, and 2 parts by mass of 2,2′-azobisisobutyronitrile were charged. Next, after the air in the reaction vessel was replaced with nitrogen gas, the temperature in the reaction vessel was raised to 75 ° C. while stirring in a nitrogen atmosphere, and the reaction was performed for 10 hours.
After the reaction, the reaction solution in the reaction vessel was diluted with toluene until the solid content became 30% by mass to obtain a solution of an acrylic copolymer (A-1).
With respect to the mass average molecular weight of the obtained acrylic copolymer (A-1), a value in terms of standard polystyrene was measured by gel permeation chromatography (GPC) and found to be 30000. Further, when the Si ratio of the acrylic copolymer (A-1) was measured as follows, it was 0% by mass. These results are shown in Table 1 below.

After drying the solution of the acrylic copolymer (A-1) to remove toluene, a sample of about 0.2 g was taken from the dried acrylic copolymer (A-1), and a thermogravimetric measurement device ( Set to "Q500 type" manufactured by TA Instruments Japan Co., Ltd.). First, measurement was started from room temperature, and the temperature was raised to 1000 ° C. at a rate of 5 ° C./min. Then, the remaining amount after the temperature rise was measured, and the silicon content (Si ratio) in the acrylic copolymer (A-1) was determined.

<Production of acrylic copolymers (A-2) to (A-6)>
The acrylic copolymers (A-2) to (A-6) were prepared in the same manner as the acrylic copolymer (A-1) except that the composition of the monomer mixture was changed as shown in Table 1 below. A solution was obtained.
The mass average molecular weight and Si ratio of the obtained acrylic copolymers (A-2) to (A-6) were measured in the same manner as the acrylic copolymer (A-1). The results are shown in Table 1 below.

Abbreviations in Table 1 are as follows.
MMA: methyl methacrylate, BA: n-butyl acrylate, KBE-503: 3-methacryloxypropyltriethoxysilane (group represented by formula (1) (R ¹ = ethyl group, m = 3), Monomer having a methacryloyl group) (Shin-Etsu Chemical Co., Ltd., "KBE-503")
KBM-503: 3-methacryloxypropyltrimethoxysilane (monomer having a group represented by the formula (1) (R ¹ = methyl group, m = 3) and a methacryloyl group) (Shin-Etsu Chemical Co., Ltd.) Made by company, "KBM-503")
AIBN: 2,2′-azobisisobutyronitrile

"Example 1"
<Manufacture of paints>
As component (A), 100 parts by mass of a solution of acrylic copolymer (A-3) in terms of solid content, and as component (B), dimethyl silicone oil having silanol groups at both ends (momentive performance material) "XC96-723", mass average molecular weight 700) 0.6 parts by mass, 2 parts by mass of dibutyltin dilaurate as component (C), and aromatic hydrocarbon (Yamaichi as organic solvent) 1500 parts by mass of “YS-100” manufactured by Chemical Industry Co., Ltd. was mixed to prepare a paint.
About the obtained coating material, water repellency and oil repellency were evaluated as follows. The results are shown in Table 2 below.

<Evaluation of water repellency 1>
The paint was spray-coated on the surface of the degreased glass plate so as to be ² g / m ^2, and then heat-treated at 130 ° C. for 30 minutes to form a coating film on the glass plate. Immediately thereafter, 2 μL of water was dropped onto the surface of the coating film, and the contact angle of water was measured using a contact angle measuring device (contact angle type CA-DT manufactured by Kyowa Interface Science Co., Ltd.). Evaluated.
A (Excellent): The receding contact angle is 120 ° or more.
○ (excellent): the receding contact angle is 90 ° or more and less than 120 °.
Δ (good): The receding contact angle is 60 ° or more and less than 90 °.
X (Inferior): The receding contact angle is less than 60 °.
XX (defect): Water spreads wet.

<Evaluation of water repellency 2>
A paint was spray-coated on the surface of the degreased glass plate so as to be ² g / m ^2, and then heat-treated at 80 ° C. for 30 minutes to form a coating film on the glass plate. Immediately thereafter, 2 μL of water was dropped on the surface of the coating film, and the contact angle of water was measured using a contact angle measuring device (contact angle type CA-DT manufactured by Kyowa Interface Science Co., Ltd.). The evaluation criteria in this case are the same as in the case of water repellency evaluation 1.

<Evaluation of water repellency 3>
A paint was spray-coated on the surface of the degreased glass plate so as to be ² g / m ^2, and then heat-treated at 80 ° C. for 30 minutes to form a coating film on the glass plate. Then, it was left to stand at room temperature (25 ° C.) for 7 days. After standing, 2 μL of water was dropped on the surface of the coating film, and the contact angle of water was measured using a contact angle measuring device (contact angle type CA-DT manufactured by Kyowa Interface Science Co., Ltd.). The evaluation criteria in this case are the same as in the case of water repellency evaluation 1.

<Evaluation of oil repellency 1>
The paint was spray-coated on the surface of the degreased glass plate so as to be ² g / m ^2, and then heat-treated at 130 ° C. for 30 minutes to form a coating film on the glass plate. Immediately thereafter, 2 μL of toluene was dropped on the surface of the coating film, and the contact angle of toluene was measured using a contact angle measuring device (contact angle type CA-DT manufactured by Kyowa Interface Science Co., Ltd.). Evaluated.
○ (excellent): Toluene receding contact angle is 60 ° or more.
Δ (good): The toluene receding contact angle is less than 60 °.
X (Inferior): Toluene spreads wet.

<Evaluation of oil repellency 2>
A paint was spray-coated on the surface of the degreased glass plate so as to be ² g / m ^2, and then heat-treated at 80 ° C. for 30 minutes to form a coating film on the glass plate. Immediately thereafter, 2 μL of toluene was dropped onto the surface of the coating film, and the contact angle of toluene was measured using a contact angle measuring device (contact angle type CA-DT manufactured by Kyowa Interface Science Co., Ltd.). The evaluation criteria at this time are the same as in the case of the oil repellency evaluation 1.

<Evaluation 3 of oil repellency>
A paint was spray-coated on the surface of the degreased glass plate so as to be ² g / m ^2, and then heat-treated at 80 ° C. for 30 minutes to form a coating film on the glass plate. Then, it was left to stand at room temperature (25 ° C.) for 7 days. After standing, 2 μL of toluene was dropped on the surface of the coating film, and the contact angle of toluene was measured using a contact angle measuring device (contact angle type CA-DT manufactured by Kyowa Interface Science Co., Ltd.). The evaluation criteria at this time are the same as in the case of the oil repellency evaluation 1.

“Examples 2 to 22, Comparative Examples 1 to 5”
A coating material was prepared in the same manner as in Example 1 except that the types and blending amounts of the components (A), (B) and (C) were changed as shown in Tables 2 to 5 below. Oiliness was evaluated. The results are shown in Tables 2 to 5 below.

In Tables 2 to 5, the blending amount of component (A) is a solid content conversion amount. Abbreviations in Tables 2 to 5 are as follows.
DMS-S12: Dimethyl silicone oil having silanol groups at both ends (Gelest, Incorporated, “DMS-S12”, weight average molecular weight 550)
XC96-723: Dimethylsilicone oil having silanol groups at both ends (manufactured by Momentive Performance Materials Japan GK, “XC96-723”, mass average molecular weight 700)
DMS-S15: Dimethyl silicone oil having silanol groups at both ends (Gelest, Incorporated, “DMS-S15”, weight average molecular weight 2750)
YF3800: Dimethyl silicone oil having silanol groups at both ends (Momentive Performance Materials Japan GK, “YF3800”, weight average molecular weight 6000)
PMX-0930: Dimethyl silicone oil having silanol groups at both ends (manufactured by Toray Dow Corning Co., Ltd., “PMX-0930”, weight average molecular weight 12500)
XF3905: Dimethyl silicone oil having silanol groups at both ends (Momentive Performance Materials Japan GK, “XF3905”, weight average molecular weight 20000)
KF96-100cs: Dimethylpolysiloxane (dimethylsilicone oil having no silanol groups at both ends) (“KF96-100cs”, mass average molecular weight 6000, manufactured by Shin-Etsu Chemical Co., Ltd.)
-DBTDL: Dibutyltin dilaurate-TA-23: Titanium tributoxy dimer (Matsumoto Fine Chemical Co., Ltd., "Orgatrix TA-23")
A-1001: Aluminum trisecondary butoxide (Matsumoto Fine Chemical Co., Ltd., “A-1001”)
YS-100: aromatic hydrocarbon solvent (manufactured by Yamaichi Chemical Co., Ltd., “YS-100”, boiling point 163 to 175 ° C.)

As is clear from Tables 2 to 4, the coating film formed from the paint of each example was excellent in water repellency. Particularly, with respect to 100 parts by mass of component (A), the content of component (B) is 10 parts by mass or less, the content of component (C) is 2 parts by mass or more, and the mass of component (B) The coating films formed from the paints of Examples 1 to 11, 13, 15, 16, and 18 to 22 having an average molecular weight of 12,500 or less were generally excellent in oil repellency.
Further, both the water repellency and the oil repellency tend to be improved in the coating film after the heat treatment at 80 ° C. for 30 minutes and then left at 25 ° C. for 7 days than the coating film immediately after the heat treatment at 80 ° C. for 30 minutes. It was shown that
The paints of Examples 1 to 18, 21, and 22 had a longer pot life than the paints of Examples 19 and 20.

On the other hand, as is clear from Table 5, the coating material of Comparative Example 1 in which the content of the component (B) is 0.4 parts by mass with respect to 100 parts by mass of the component (A), and the comparison not including the component (B) The coating film formed from the paint of Example 3 was inferior in water repellency and oil repellency.
The coating film formed from the paint of Comparative Example 2 using dimethylpolysiloxane having no hydroxy group at both ends was inferior in water repellency and oil repellency.
The coating film formed from the coating material of Comparative Example 4 using an acrylic copolymer having no alkoxyl group was inferior in water repellency and oil repellency.
The coating film formed from the coating material of Comparative Example 5 having a catalyst content of 0.4 parts by mass with respect to 100 parts by mass of the component (A) was inferior in water repellency and oil repellency.

The coating material of the present invention can form a coating film with excellent water repellency even when heat-treated at a low temperature, and since the coating film of the present invention has excellent water repellency, it can protect the surface of a substrate and impart design properties. It is very suitable for the intended use.

Claims

Containing an acrylic copolymer having an alkoxysilyl group, dimethylpolysiloxane having hydroxy groups at both ends, and a metal catalyst,
The coating material whose content of the said dimethylpolysiloxane is 0.5 mass part or more with respect to 100 mass parts of said acrylic copolymers, and whose content of the said metal catalyst is 1.0 mass part or more.
A coating film obtained by heat-treating the paint according to claim 1 at 60 to 250 ° C. for 30 seconds to 60 minutes.