JP2017066284A - Resin composition for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for a coating having excellent storage stability, capable of providing a coating which can be cured without being affected by an ambient humidity condition, and has high substrate followability since curing shrinkage hardly occurs, and further can form a coating film having excellent weather resistance.SOLUTION: There is provided a resin composition for a coating containing a reaction product of following (A) and (B), (A) an organopolysiloxane compound having 2 or more amino groups in a molecule, but not containing -Si-OH group nor -Si-O-C- group and having amine equivalent of 300 to 6,000 g/eq, (B) a resin having an organic functional group capable of reacting to the amino group and a hydroxyl group in a molecule and having weight average molecular weight of 3,000 to 100,000 and hydroxyl group value of 10 to 200 mgKOH/g, where the reaction product has a hydroxyl group in a molecule and the reaction product forms a coating film by a reaction to an isocyanate compound.SELECTED DRAWING: None

Description

  The present invention relates to a coating resin composition.

As a system for forming a coating film by curing a two-component curable coating, there is generally a urethane curing system using an acrylic polyol resin and an isocyanate compound. The two-component urethane curing system can form a coating film excellent in substrate adhesion and flexibility at low cost.
As another curing system, there is a silicone curing system using an acrylic silicone resin obtained by introducing a silanol group or a group that generates a silanol group by hydrolysis into an acrylic resin (Patent Document 1). In the silicone curing system, the coating film is cured by a condensation reaction of the introduced silanol groups (including those produced by hydrolysis).
In addition, as an example in which a urethane curing system and a silicone curing system are used in combination, as an acrylic polyol resin used in a urethane curing system, a group that generates a silanol group by hydrolysis is introduced into the resin and coexisted with a hydroxyl group. Technology exists (Patent Document 2).

Japanese Patent No. 3218948 Patent No. 5116914

In the urethane curing system, since the main crosslink formed between the acrylic polyol resin and the isocyanate compound is a urethane bond, the weather resistance of the coating film is poor.
In the silicone curing system described in Patent Document 1, since a coating film is cured using a silanol group having low stability, it is necessary to add a stabilizer in order to ensure the storage stability of the paint. Silicone curing systems are easily affected by ambient humidity conditions, and when cured at room temperature without heat curing, curing alone is extremely slow, so a curing accelerator (organometallic catalyst, acid or base) is used as a paint. It is necessary to blend in. Furthermore, in the silicone curing system, alcohol and water, which are by-products, are generated by the condensation reaction, and the crosslinking points due to the condensation reaction are likely to increase. And may cause defects such as cracking and peeling of the coating film.
Even in the combined system described in Patent Document 2, since the coating film is cured using an alkoxysilyl group or a silanol group generated by hydrolysis of the alkoxysilyl group, the same problem as in the silicone curing system described above exists. Further, although not limited to a specific theory, a reaction intermediate having a silylurethane (—Si—O—C (═O) —NH—) bond is generated by a reaction between a silanol group and an isocyanate, It becomes a factor which delays coating film hardening. Since this silylurethane bond is weak against water, alcohol and the like, there is a concern that the physical properties of the coating film may be adversely affected, such as a decrease in hardness and chemical resistance of the obtained coating film.

  As a result of intensive studies on the above-mentioned problems, the present inventor has found that an organosiloxane compound having no amino group and further having a predetermined amine equivalent does not have -Si-OH and -Si-OC- groups. A reaction product of a resin having an organic functional group capable of reacting with a group and a hydroxyl group in the molecule, a weight average molecular weight of 3000 to 100,000, and a hydroxyl value of 10 to 200 mgKOH / g, and isocyanate The resin composition for coating by reaction with a compound is (1) excellent in storage stability, and further, when used as a coating, (2) can be cured without being affected by ambient humidity conditions, and (3) It has been found that since there is no by-product formation during curing, curing shrinkage of the coating film is difficult to occur, the substrate follow-up property of the coating film becomes high, and (4) a coating film having further excellent weather resistance can be formed. . The present invention has been made based on this finding.

That is, the present invention relates to the following 1 to 6.
1. A resin composition for paint,
The coating resin composition includes a reaction product of the following (A) and (B):
(A) An organopolysiloxane compound having two or more amino groups in the molecule but not containing -Si-OH group and -Si-OC- group, and having an amine equivalent of 300 to 6000 g / eq. An organopolysiloxane compound,
(B) a resin having an organic functional group capable of reacting with an amino group and a hydroxyl group in the molecule, a weight average molecular weight of 3000 to 100,000, and a hydroxyl value of 10 to 200 mgKOH / g;
The reaction product has a hydroxyl group in the molecule;
The reaction product forms a coating film by reaction with an isocyanate compound;
Resin composition for paint.

2. 2. The resin composition for coatings according to 1 above, wherein the siloxane bond in the organopolysiloxane compound (A) contains one or more three-way branched structures (T structures).

3. 3. The paint resin composition according to 1 or 2 above, wherein the organic functional group of (B) is an epoxy group.

4). 4. The resin composition for coatings according to any one of 1 to 3, wherein the reaction product of (A) and (B) further has an amino group in the molecule.

5. The coating material containing the resin composition for coating materials as described in any one of said 1-4.

6). 6. An article coated with the paint described in 5 above.

  As shown in Examples described later, the coating resin composition of the present invention is (1) excellent in storage stability, and (2) providing a curable coating without being affected by ambient humidity conditions. (3) It is possible to provide a coating material that is difficult to cause curing shrinkage and has a high substrate followability, and (4) a coating material that can form a coating film having excellent weather resistance.

Hereinafter, the present invention will be described in more detail.
The coating resin composition of the present invention contains a reaction product of (A) an organopolysiloxane compound and (B) a resin.

Component (A): Organopolysiloxane compound (A) is an organopolysiloxane compound that satisfies the following conditions (1) to (3).
(1) It has two or more amino groups in the molecule.
(2) Does not contain -Si-OH group and -Si-O-C- group.
(3) The amine equivalent is 300 to 6000 g / eq.

The organopolysiloxane compound refers to a compound including a main chain composed of a siloxane bond (—Si—O—) and an organic substituent bonded to the main chain.
Although there is no restriction | limiting in particular in the length of a principal chain, From a viewpoint of easy reactivity with (B) component and stability, Preferably it is 500-12000 in a number average molecular weight, More preferably, it is 800-5000. The number average molecular weight in the present invention is a value determined by a method of using polystyrene as a standard substance in gel permeation chromatography and determining the molecular weight of the sample by relative comparison between the polystyrene and the sample. Also called average molecular weight. The number average molecular weight can be measured according to a method known in the art. The above explanation of the number average molecular weight is also applied to the number average molecular weight of the resin of the component (B) described later.
As the organic substituent bonded to the silicon atom of the main chain, generally, an alkyl group such as a methyl group or an ethyl group (for example, a methyl group or an ethyl group), an aryl group (for example, a phenyl group), an alkoxy group Examples include a group (for example, methoxy group and ethoxy group), a carboxyalkyl group, an alkyl glycidyl ether group, an aminoalkyl group (for example, aminopropyl group, aminoethyl group, etc.) and the like.

  The organopolysiloxane compound has two or more amino groups in its molecule. The amino group may be an amino group directly bonded to the main chain, or may be an amino group portion of the above-described aminoalkyl group. The number of amino groups is 2-20, preferably 2-14, more preferably 2-8. When the number of amino groups is 2 to 20, the reactivity with the component (B) is improved, and a coating resin composition having excellent storage stability can be obtained. Furthermore, when the resin composition for paint is applied to a paint, a paint having excellent storage stability can be obtained.

The organopolysiloxane compound does not contain -Si-OH group in the molecule.
Furthermore, the organopolysiloxane compound does not contain a —Si—O—C— group.

In the organopolysiloxane compound, the siloxane bond may have a straight chain structure (two-way branched structure: D structure) in which two oxygen atoms are bonded to silicon atoms, and the three oxygen atoms are silicon. Although it may have a structure bonded to atoms (3-way branched structure: T structure), it preferably has a 3-way branched structure. When it has a three-way branched structure, it is possible to obtain a coating film with more excellent durability. The number of three-way branched structures in the organopolysiloxane compound is preferably 2 to 40, and more preferably 2 to 20.
Further, the organopolysiloxane compound may have both a two-way branched structure (D structure) and a three-way branched structure (T structure).

The amine equivalent of the organopolysiloxane compound is 300 to 6000 g / eq, preferably 300 to 4000 g / eq, more preferably 300 to 2500 g / eq. When the amine equivalent is 300 to 6000 g / eq, the reactivity with the component (B) is improved, and a coating resin composition having excellent storage stability can be obtained.
Amine equivalents can be calculated according to methods known in the art. For example, it is possible to determine the total number of amines present in the organopolysiloxane compound by determining the number of mg of hydrochloric acid required to neutralize the amino group in 1 g of the organopolysiloxane compound, and to calculate the amine equivalent from this value. it can.

  The amino group of the organopolysiloxane compound may be an amino group portion of an aminoalkyl group as an organic group bonded to the main chain. In this case, a secondary or primary amino group bonded to the polysiloxane main chain via a carbon atom is preferable, and a primary amino group is more preferable. When the amino group has this structure, the reactivity with the organic functional group of the component (B) that reacts with the amino group is increased, and as a result, a coating film excellent in curability, chemical resistance and weather resistance can be obtained. .

The organopolysiloxane compound used as the component (A) can be easily obtained on the market, but can be prepared by a known method.
For example, it can be prepared by a hydrosilylation reaction between N- (3-aminopropyl) methacrylamide and methyl hydrogen silicone oil or a Michael addition reaction between ethylenediamine and silsesquioxane having a vinyl group.
Specific examples of the organopolysiloxane compound include trade names: KF-8010 (manufactured by Shin-Etsu Chemical Co., Ltd., both end amino-modified polydimethylsiloxane type silicone oil), DC3055 (manufactured by Dow Corning Corp., amino group-containing silicone resin). ), KF-8012 (manufactured by Shin-Etsu Chemical Co., Ltd., both terminal amino-modified polydimethylsiloxane type silicone oil), Wacker FLUID NH 40 D (manufactured by Wacker Chemie AG, both terminal amino-modified silicone oil), and the like.

  As the component (A), one type of compound may be used alone, or two or more types may be used in combination.

(B) component: Resin (B) component is resin which satisfy | fills the following conditions (1)-(2).
(1) It has an organic functional group capable of reacting with an amino group and a hydroxyl group in the molecule.
(2) The weight average molecular weight is 3000 to 100,000.

The “organic functional group capable of reacting with an amino group” refers to an organic functional group capable of reacting with the amino group of the organopolysiloxane compound (component (A)).
Specific examples include an epoxy group, a carboxyl group, and an ethylenically unsaturated double bond group (for example, a methacryloyl group). An epoxy group and a carboxyl group are preferable, and an epoxy group is more preferable.

The amount of the “organic functional group capable of reacting with an amino group” contained in the resin is not particularly limited.
When the resin contains an epoxy group as an organic functional group, the number of epoxy groups per molecule of the resin is preferably 1 to 3. When the number of epoxy groups is 1 or more, a coating film excellent in storage stability and weather resistance can be obtained. Moreover, the gelation by rapid reaction with (A) component can be suppressed as the number of epoxy groups is 3 or less. The number of epoxy groups contained in the resin can be calculated by dividing the number average molecular weight of the resin by the epoxy equivalent. The epoxy equivalent can be calculated according to a method known in the art.

  When the resin contains a carboxyl group as an organic functional group, the number of carboxyl groups per molecule of the resin is preferably 1 to 3. When the number of carboxyl groups is 1 or more, a coating film excellent in storage stability and weather resistance can be obtained. Moreover, the gelation by rapid reaction with (A) component can be suppressed as the number of carboxyl groups is 3 or less. The number of carboxyl groups contained in the resin can be calculated by dividing the number average molecular weight of the resin by the carboxyl group equivalent. The carboxyl group equivalent can be calculated according to a method known in the art.

  If the resin is modified with an organic molecule containing an ethylenically unsaturated double bond group for modification of the resin in addition to the “base monomer” described later used for the production of the resin main chain, the modified resin The number of ethylenically unsaturated double bond groups derived from the organic molecule per molecule is preferably 1 to 3. When the number of ethylenically unsaturated double bond groups is 1 or more, a coating film excellent in storage stability and weather resistance can be obtained. Moreover, the gelatinization by rapid reaction with (A) component can be suppressed as the number of ethylenically unsaturated double bond groups is 3 or less. The number of ethylenically unsaturated double bond groups contained in the resin can be calculated by dividing the number average molecular weight of the resin by the ethylenically unsaturated double bond equivalent. The ethylenically unsaturated double bond equivalent can be calculated according to a method known in the art.

The resin has a hydroxyl group in addition to the aforementioned organic functional group.
The amount of the “hydroxyl group” in the resin is 10 to 200 mgKOH / g, preferably 25 to 100 mgKOH / g, more preferably 25 to 90 mgKOH / g. When the hydroxyl value is 10 to 200 mg KOH / g, the coating film can be cured more easily by reacting with a curing agent of a coating, for example, an isocyanate compound that reacts with a hydroxyl group, and the curability, weather resistance, water resistance and water resistance are improved. A coating film superior in chemical properties can be obtained. The hydroxyl value can be measured according to a method known in the art.

  The weight average molecular weight of the resin is 3,000 to 100,000, preferably 5,000 to 100,000, and more preferably 10,000 to 100,000. The weight average molecular weight in the present invention is a value determined by a method of determining the molecular weight of a sample by relative comparison between polystyrene and a sample using polystyrene as a standard substance in gel permeation chromatography. Also called average molecular weight. The weight average molecular weight can be measured according to a method known in the art.

About the kind of resin, resin which satisfy | fills said (1)-(2) conditions can be especially used without a restriction | limiting.
The resin may be a polymer prepared from one type of monomer, or may be a copolymer prepared from two or more types of monomers.
The resin can be produced using a production method known in the art. For example, in the case of an acrylic resin, a “base monomer” constituting the main chain of the resin and a “reactive organic functional group-containing monomer” that introduces an organic functional group capable of reacting with an amino group into the main chain, Resin can be manufactured by copolymerizing using a polymerization initiator in presence.

When using a resin having a main chain of a copolymer of acrylic acid ester and styrene, as a base monomer, styrene, methacrylic acid ester (for example, methyl methacrylate or 2-ethylhexyl methacrylate), acrylic acid ester ( Examples thereof include 2-ethylhexyl acrylate and butyl acrylate).
As the base monomer, one type of monomer may be used alone, or two or more types may be used in combination.

When a resin having a main chain of a copolymer of acrylic acid ester and styrene is used, the reactive organic functional group-containing monomer includes acrylic acid, 2-hydroxyethyl methacrylate, glycidyl methacrylate, methacrylic acid, methacrylic acid 2 -Isocyanatoethyl and the like.
As the reactive organic functional group-containing monomer, one type of monomer may be used alone, or two or more types may be used in combination.

Specific examples of the component (B) include an acrylic resin having an epoxy group and a hydroxyl group, and an epoxy resin having a secondary hydroxyl group that has been extended by ring-opening polymerization between low-molecular epoxy resins. From the viewpoint of curability and weather resistance, an acrylic resin is preferred.
In addition, specific examples of the component (B) include an organic functional group (for example, an epoxy group) capable of reacting with an amino group together with a base monomer and a reactive organic functional group-containing monomer in the production of a hydroxyl group-containing acrylic resin. And / or an organic functional group-modified alkyd acrylic resin obtained by adding and reacting an alkyd resin having a carboxyl group),
An organic functional group-modified fluororesin having a vinylidene group and a hydroxyl group obtained by reacting some hydroxyl groups of a hydroxyl group-containing fluororesin with 2-isocyanatoethyl methacrylate is exemplified.

  The resin of component (B) may be a solution or a dispersion. Among these, a solution form is preferable from the point of compatibility with the component (A).

The resin solution can be manufactured using a manufacturing method known in the technical field.
As the solvent in the resin solution, those generally used for the resin to be used can be used without particular limitation. For example, the solvent is a solvent used during resin production. When the resin is a copolymer of acrylic acid ester and styrene, the solvent includes petroleum solvents (for example, mineral spirits and aromatic hydrocarbon solvents), and ketone solvents (for example, acetone and methyl ethyl ketone). Etc.
The resin solution may contain a dehydrating agent, an antifoaming agent, an ultraviolet absorber, a light stabilizer, a viscosity modifier, a surface preparation agent, a low contamination agent, a catalyst, a polymerization inhibitor, and the like as optional components.

The resin dispersion can be produced using a production method known in the art.
As the solvent for the resin dispersion, the same solvent as the solvent for the resin solution described above can be used.
The resin dispersion may contain, as optional components, a dehydrating agent, an antifoaming agent, an ultraviolet absorber, a light stabilizer, a viscosity modifier, a surface preparation agent, a low contamination agent, a catalyst, a polymerization inhibitor, and the like.

Reaction product of component (A) and component (B) The reaction product is obtained by reacting the component (A) and the component (B).
The reaction conditions are not particularly limited as long as the “amino group” of the component (A) and the “organic functional group capable of reacting with the amino group” of the component (B) can be reacted. Addition or heating of a catalyst (for example, an acid such as sulfuric acid or phosphoric acid, a base such as a tertiary amine, or an organic metal catalyst) suitable for the reaction with “an organic functional group capable of reacting with an amino group” (for example, 60 to 150 ° C. is preferable because the reaction product can be obtained with higher yield.

The reaction product has a hydroxyl group in the molecule. The reaction product preferably has an amino group in addition to a hydroxyl group in the molecule.
Although the present invention is not limited to a specific theory, when forming a coating film, the hydroxyl group and amino group of the reaction product react with the isocyanate group of the isocyanate compound to form a urethane bond and a urea bond, respectively. This urethane bond and urea bond are considered to impart excellent curability, substrate adhesion (substrate followability), flexibility, chemical resistance, and the like to the coating film. Moreover, in the coating film formed by curing the urethane bond and urea bond, an organopolysiloxane compound (component (A)) having a siloxane bond having excellent weather resistance exists as a partially arranged block compound. Thus, weather resistance can be imparted to the coating film.
The amount of the “hydroxyl group” in the reaction product is not particularly limited, but the hydroxyl value of the solid content of the reaction product is preferably 10 to 200 mgKOH / g, more preferably 25 to 100 mgKOH / g. When the hydroxyl value is 10 to 200 mgKOH / g, a more excellent coating film can be obtained. The hydroxyl value can be measured according to a method known in the art.

The reaction product reacts with an isocyanate compound (paint curing agent) to form a coating film.
The isocyanate compound is used for curing the reaction product to form a coating film.
Specific examples of the isocyanate compound include bifunctional or higher functional isocyanate compounds (for example, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc.), burette type compounds, isocyanurate type compounds, adduct type compounds of the isocyanate compounds. And polyisocyanate compounds. The isocyanate compound to be used is not particularly limited, but from the viewpoint of improving the weather resistance of the coating film, it has an aliphatic chain type or alicyclic structure, and is a bifunctional or higher isocyanate compound, its burette type compound, isocyanurate type Compounds, adduct type compounds and polyisocyanate compounds are preferred.

  In addition, the active hydrogen value (NH value) of the solid content of the reaction product (an index of the amount of the reaction active component in the amino group of the reaction product) is preferably 5 to 20. When the active hydrogen value is 5 to 20, it becomes easier to control the correlation between the curability of the coating film and the pot life of the coating film. The active hydrogen value can be calculated according to a method known in the art.

Resin Composition The resin composition for coatings of the present invention contains the above-mentioned (A) reaction product of an organopolysiloxane compound and (B) resin as an essential component.

The coating resin composition may be the reaction liquid (reaction liquid containing the reaction product) itself obtained when producing the reaction product of the above-mentioned component (A) and component (B), What added the solvent, the additive, etc. further to the reaction liquid may be used.
As the solvent to be added, those used as paint solvents can be used without particular limitation. Specific examples of the solvent include petroleum solvents (for example, mineral spirit), ketone solvents (for example, methyl ethyl ketone), and the like.
As additives to be added in addition to the solvent, those used in paints can be used without particular limitation. Specific examples of the additive include a dehydrating agent, an antifoaming agent, an ultraviolet absorber, a light stabilizer, a viscosity modifier, a surface preparation agent, a low contamination agent, a catalyst and a polymerization inhibitor.

  The content of the reaction product (solid content) in the coating resin composition is not particularly limited, but is preferably 10 to 100 mass%, more preferably 30 to 100 mass%, based on the total mass of the coating resin composition. More preferably, it is 50-100 mass%. The weather resistance of a cured coating film can be improved more as it is 10-100 mass%.

Method for Using Paint Resin Composition The paint resin composition of the present invention is used in paints. For example, a paint can be produced by mixing a resin composition for paint, a pigment and various additives, and dispersing the pigment in the resin composition. Moreover, the coating film excellent in weather resistance can be formed by mixing this coating material and a coating-curing agent, and apply | coating to a to-be-coated article.

As a pigment, what is used for the coating material can be especially used without a restriction | limiting. Specific examples of the pigment include coloring pigments and extender pigments.
One kind of pigment may be used alone, or two or more kinds of pigments may be used in combination.

The paint curing agent is an isocyanate compound that can form a coating film by reacting with the reaction product of the aforementioned component (A) and component (B).
Specific examples of the isocyanate compound include bifunctional or higher functional isocyanate compounds (for example, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, etc.), burette type compounds, isocyanurate type compounds, adduct type compounds of the isocyanate compounds. And polyisocyanate compounds. The isocyanate compound to be used is not particularly limited, but from the viewpoint of improving the weather resistance of the coating film, it has an aliphatic chain type or alicyclic structure, and is a bifunctional or higher isocyanate compound, its burette type compound, isocyanurate type Compounds, adduct type compounds and polyisocyanate compounds are preferred.
Isocyanate compounds are readily available on the market or can be prepared by known methods.
As the coating curing agent, one type of isocyanate compound may be used alone, or two or more types may be used in combination.

  The content of the resin composition for paint in the paint is not particularly limited. For example, the content is preferably 10 to 100% by weight, more preferably 30 to 100% by weight, and still more preferably 50 to 100% by weight with respect to the total weight of the paint. It is.

  In addition, a viscosity modifier, a dehydrating agent, an antifoaming agent, an ultraviolet absorber, a light stabilizer, a surface preparation agent, a low-contamination agent, a catalyst, and the like can be appropriately added to the paint as additives.

The paint produced from the resin composition for paint according to the present invention can be used in the same coating method as a general paint.
Although there is no restriction | limiting in particular in the kind of articles coated with the coating material manufactured from the resin composition for coatings of this invention, It uses suitably for top coat coatings, such as a steel plate, the exterior of a general building, a concrete structure, and a steel structure be able to.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

1. Preparation of Resin Composition for Paint A paint resin composition was prepared according to the following preparation example. In addition, resin composition for coating resin composition and organopolysiloxane compound as a precursor thereof, resin solid content of acrylic resin solution and acrylic resin dispersion, acid value, carboxyl group equivalent, hydroxyl value, epoxy equivalent, amine equivalent, active hydrogen ( (NH) value, ethylenically unsaturated double bond group equivalent, number average molecular weight and weight average molecular weight were measured and calculated by the following methods.

<Resin solids>
1.0 g of resin solution, resin dispersion or resin composition was precisely weighed in an aluminum cup and dried in a 150 ° C. oven for 30 minutes. After drying, the mass of the residue was precisely weighed, and the ratio of the mass of the residue to the original mass was determined as the resin solid content (mass%).

<Acid value>
In accordance with the method described in JIS K 5601-2-1, the number of mg of potassium hydroxide required to neutralize the free acid in 1 g of the resin was quantified to determine the acid value of the resin solid content.

<Carboxyl group equivalent>
Using the acid value calculated above, the carboxyl equivalent of the resin solid content was calculated.

<Hydroxyl value>
After free acetylation in 1 g of the resin was completely acetylated with acetic anhydride, the number of mg of potassium hydroxide required to neutralize it was quantified to determine the hydroxyl value of the solid content of the resin.

<Epoxy equivalent>
The epoxy equivalent was calculated according to the indicator titration method described in JIS K 7236.

<Amine equivalent>
The amine equivalent of the resin sample was calculated from the amount of raw materials used for sample preparation.

<Active hydrogen value (NH value)>
After calculating the active hydrogen equivalent using the amine equivalent value calculated above, the active hydrogen value (NH value) per hydrogen of the amine contained in the resin sample was calculated.

<Equivalent ethylenically unsaturated double bond group>
After synthesizing the acrylic resin, the ethylenically unsaturated double bond equivalent was calculated from the charged amount of the raw material having an ethylenically unsaturated double bond used for modification of the resin.

<Number average molecular weight (polystyrene equivalent number average molecular weight)>
The number average molecular weight (Mn) was measured by GPC (manufactured by Tosoh Corp .; HLC-8220 GPC) equipped with RI using a TSKgel column (Tosoh Corp.). As GPC conditions, tetrahydrofuran was used as a developing solvent, and measurement was performed at a flow rate of 0.35 ml / min and a temperature of 40 ° C. TSK standard polystyrene (manufactured by Tosoh Corporation) was used as a standard substance.

<Weight average molecular weight (polystyrene equivalent weight average molecular weight)>
The weight average molecular weight (Mw) was measured by GPC (manufactured by Tosoh Corporation; HLC-8220 GPC) equipped with RI using a TSKgel column (manufactured by Tosoh Corporation). As GPC conditions, tetrahydrofuran was used as a developing solvent, and measurement was performed at a flow rate of 0.35 ml / min and a temperature of 40 ° C. TSK standard polystyrene (manufactured by Tosoh Corporation) was used as a standard substance.

1-1. Component (A): Obtaining or Preparing Organopolysiloxane Compound The following organopolysiloxane compound was obtained or prepared.

1-1-1. KF-8010
KF-8010 (manufactured by Shin-Etsu Chemical Co., Ltd., both terminal amino-modified polydimethylsiloxane type silicone oil) has two amino groups in the molecule, but has Si-OH group and -Si-O-C- group. It is an organopolysiloxane compound not contained.
The amine equivalent of KF-8010 was 430 g / eq.
The number average molecular weight of the main chain of KF-8010 was 860. The organic substituents bonded to the main chain were an aminoalkyl group and a methyl group.
KF-8010 was a compound having only a two-way branched structure (D structure).

1-1-2. DC3055
DC3055 (manufactured by Dow Corning Corp., an amino group-containing silicone resin) has 5 (estimated) amino groups in the molecule, but does not contain Si—OH groups and —Si—O—C— groups. It is a siloxane compound.
The amine equivalent of DC3055 was 520 g / eq.
The number average molecular weight of the main chain of DC3055 was 1300. The organic substituents bonded to the main chain were aminoalkyl group, methyl group and phenyl group.
DC3055 was a compound having a two-way branched structure (D structure) and a trigonal branched structure (T structure) of 2 to 20 inclusive.

1-1-3. MCR-A11
MCR-A11 (manufactured by Gelest Inc., one-terminal amino-modified polydimethylsiloxane type silicone oil) has one amino group in the molecule, but does not contain -Si-OH group and -Si-O-C- group. It is an organopolysiloxane compound.
The amine equivalent of MCR-A11 was 350 g / eq.
Moreover, the number average molecular weight of MCR-A11 was 350. The organic substituents bonded to the main chain were aminopropyl group, methyl group and butyl group.
MCR-A11 was a compound having only a two-way branched structure (D structure).

1-1-4. KF-54
KF-54 (manufactured by Shin-Etsu Chemical Co., Ltd., polyphenylmethylsiloxane type silicone oil) does not have an amino group in the molecule, and does not contain an —Si—OH group or an —Si—O—C— group. It is a polysiloxane compound.
The amine equivalent of KF-54 was 0 g / eq.
Further, the number average molecular weight of KF-54 could not be measured. The organic substituents bonded to the main chain were a methyl group and a phenyl group.
KF-54 was a compound having only a two-way branched structure (D structure).

1-1-5. PAM-E
PAM-E (manufactured by Shin-Etsu Chemical Co., Ltd., both terminal amino-modified polydimethylsiloxane type silicone oil) has two amino groups in the molecule, but has a —Si—OH group and a —Si—O—C— group. It is an organopolysiloxane compound that does not contain.
The amine equivalent of PAM-E was 130 g / eq.
The number average molecular weight of PAM-E was 260. The organic substituents bonded to the main chain were an aminoalkyl group and a methyl group.
PAM-E was a compound having only a two-way branched structure (D structure).

1-1-6. DMS-A31
DMS-A31 (manufactured by Gelest Inc., both terminal amino-modified polydimethylsiloxane type silicone oil) has two amino groups in the molecule, but does not contain —Si—OH group and —Si—O—C— group. It is an organopolysiloxane compound.
The amine equivalent of DMS-A331 was 12500 g / eq.
Moreover, the number average molecular weight of DMS-A31 was 25000. The organic substituents bonded to the main chain were aminopropyl group and methyl group.
DMS-A31 was a compound having only a two-way branched structure (D structure).

1-1-7. KF-8012
KF-8012 (manufactured by Shin-Etsu Chemical Co., Ltd., both terminal amino-modified polydimethylsiloxane type silicone oil) has two amino groups in the molecule, but has a —Si—OH group and a —Si—O—C— group. It is an organopolysiloxane compound that does not contain.
The amine equivalent of KF-8012 was 2200 g / eq.
The number average molecular weight of KF-8012 was 4400. The organic substituents bonded to the main chain were an aminoalkyl group and a methyl group.
KF-8012 was a compound having only a two-way branched structure (D structure).

1-1-8. Siloxane compound A
(First step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, etc., 40.00 parts by mass of Solvesso 100 (produced by TonenGeneral Sekiyu KK, aromatic hydrocarbon solvent), Z6018 (produced by Dow Corning Corp., silanol oligomer) ) 50.00 parts by mass were added, and this was heated and stirred at 60 ° C. to dissolve Z6018.

(Second step)
The temperature was raised to 100 ° C., and 10.00 parts by mass of 3-aminopropyltrimethoxysilane was added dropwise with stirring to obtain siloxane compound A. In addition, the resin solid content of the siloxane compound A was 60.0 mass%. Moreover, the active hydrogen value (NH value) of solid content was 104 mgKOH / g.
Since the siloxane compound A has —Si—OH group and —Si—O—C— group (—Si—OCH ₃ ) in the molecule, it does not correspond to the organopolysiloxane compound of the component (A) of the present invention. It was.

1-1-9. Siloxane compound B
A siloxane compound B was prepared in the same manner as the siloxane compound A, except that the compounds shown in Table 1 below and the amounts used were changed. The resin solid content and active hydrogen equivalent of siloxane compound B are shown in Table 1.
Since the siloxane compound B has —Si—OH group and —Si—O—C— group (—Si—OCH ₃ ) in the molecule, it does not correspond to the organopolysiloxane compound of the component (A) of the present invention. It was.

なお、表１中、各成分の使用量は、質量部で示される。

In Table 1, the amount of each component used is shown in parts by mass.

1-2. (B) Component: Preparation of acrylic resin solution According to the following preparation examples, acrylic resin solutions (acrylic resin solutions A to U) and an acrylic resin dispersion were prepared.

1-2-1. Acrylic resin solution A
(First step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, etc., 7.10 parts by mass of Solvesso 100 (manufactured by TonenGeneral Sekiyu KK, aromatic hydrocarbon solvent) and 17.00 parts by mass of mineral spirits were added. After heating and stirring this and reaching 100 ° C., styrene 6.00 parts by mass, methyl methacrylate 21.48 parts by mass, 2-ethylhexyl methacrylate 8.30 parts by mass, 2-ethylhexyl acrylate 11 90 parts by weight, 2-hydroxyethyl methacrylate 5.10 parts by weight, 1.32 parts by weight methacrylic acid and 0.60 parts by weight tertiary butyl peroxy-2-ethylhexanoate Was added dropwise over 3 hours while stirring with heating to obtain a first mixture.

(Second step)
After completion of dropping, while maintaining 100 ° C., 0.60 part by mass of tertiary butyl peroxy-2-ethylhexanoate and 0.60 part by mass of mineral spirit, Solvesso in the first mixture obtained in the first step A mixture obtained by previously mixing 100.20 parts by mass of 100 was dropped over 1 hour to obtain a second mixture. Further, stirring was continued at 100 ° C. for 2.5 hours, and then the second mixture was cooled. 18.80 parts by mass of Solvesso 100 was added to the second mixture and stirred to obtain an acrylic resin solution A.
The acrylic resin solution A was a resin solution having a carboxyl group as a “organic functional group capable of reacting with an amino group” and a hydroxyl group in the molecule.
The resin solid content of the acrylic resin solution A was 55.2% by mass.
The acrylic resin solution A has a solid hydroxyl value of 39.9 mgKOH / g, an acid value of 15.6 mgKOH / g, a carboxyl group equivalent of 3594 g / eq, a polystyrene equivalent number average molecular weight of 8100, and polystyrene equivalent. The weight average molecular weight was 39800.
Therefore, the acrylic resin solution A corresponds to the component (B) of the present invention.

1-2-2. Resin solutions BT
Resin solutions B to T were prepared in the same manner as the acrylic resin solution A, except that the compounds shown in Table 2 and the amounts used were changed. Resin solid content of resin solution, hydroxyl value, acid value, carboxyl group equivalent, epoxy equivalent, polystyrene equivalent number average molecular weight, polystyrene equivalent weight average molecular weight, organic functional group capable of reacting with amino group, resin molecule Table 2 shows the number of organic functional groups that can react with the amino groups therein.
The acrylic resin solutions J to P, S, and T were resin solutions having a carboxyl group and a hydroxyl group in the molecule as “an organic functional group capable of reacting with an amino group”.
The acrylic resin solutions B to I were resin solutions having an epoxy group as a “organic functional group capable of reacting with an amino group” and a hydroxyl group in the molecule.
The acrylic resin solution Q is a resin solution that has a hydroxyl group but does not have an “organic functional group capable of reacting with an amino group”, and did not correspond to the component (B) of the present invention.
The acrylic resin solution R is a resin solution having an epoxy group as an “organic functional group capable of reacting with an amino group” but not having a hydroxyl group, and does not correspond to the component (B) of the present invention. It was.
The acrylic resin solution S had a polystyrene-reduced weight average molecular weight of 2900 in the resin solid content, and did not correspond to the component (B) of the present invention.
The acrylic resin solution T had a hydroxyl value of 3.9 mgKOH / g of the resin solid content and did not correspond to the component (B) of the present invention.
The acrylic resin solutions B to P corresponded to the component (B) of the present invention.

  In addition, in the table | surface, the usage-amount of each component is shown by a mass part.

1-2-3. Acrylic resin solution U
(First step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, etc., 7.10 parts by mass of Solvesso 100 (produced by TonenGeneral Sekiyu KK, aromatic hydrocarbon solvent) and 17.00 parts by mass of mineral spirits were added. This was heated and stirred, and after reaching 100 ° C., 5.65 parts by mass of styrene, 19.83 parts by mass of methyl methacrylate, 7.85 parts by mass of 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate 11 29 parts by mass, 7.10 parts by mass of 2-hydroxylethyl methacrylate and 0.60 part by mass of tertiary butyl peroxy-2-ethylhexanoate were added dropwise over 3 hours. The mixture was heated and stirred to obtain a first mixture.

(Second step)
After completion of dropping, while maintaining 100 ° C., 0.60 parts by mass of tertiary butyl peroxy-2-ethylhexanoate, 0.60 parts by mass of mineral spirits and Solvesso in the first mixture obtained in the first step A mixture obtained by previously mixing 100.20 parts by mass of 100 was dropped over 1 hour to obtain a second mixture. Furthermore, after continuing stirring at 100 degreeC for 2.5 hours, 18.80 mass parts of Solvesso 100 was added and stirred to the 2nd mixture, and the 3rd mixture was obtained.

(Third step)
After completion of dilution, 2.38 parts of 2-isocyanatoethyl methacrylate were added and reacted at 100 ° C. for 2 hours. After confirming disappearance of the isocyanate group derived from 2-isocyanatoethyl methacrylate by IR (infrared absorption) spectrum measurement, the mixture was cooled to obtain an acrylic resin solution U.
The acrylic resin solution U was a resin solution having an ethylenically unsaturated double bond group (methacryloyl group) as a “organic functional group capable of reacting with an amino group” and a hydroxyl group in the molecule.
The resin solid content of the acrylic resin solution U was 55.2% by mass.
The hydroxyl value of the solid content of the acrylic resin solution U was 39.9 mgKOH / g, the ethylenically unsaturated double bond equivalent was 3596 g / eq, the number average molecular weight in terms of polystyrene was 8550, and the weight average molecular weight in terms of polystyrene was 40300. . Resin solid content of resin solution, hydroxyl value of resin solid content, ethylenically unsaturated double bond equivalent, polystyrene-equivalent number average molecular weight, polystyrene-equivalent weight average molecular weight, organic functional group capable of reacting with amino group, and resin 1 Table 3 shows the number of organic functional groups that can react with amino groups in the molecule.
Therefore, the acrylic resin solution U corresponds to the component (B) of the present invention.

  In Table 3, the amount of each component used is shown in parts by mass.

1-2-4. Acrylic resin dispersion (first step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, etc., 3.83 parts by mass of Solvesso 100 (manufactured by TonenGeneral Sekiyu KK, aromatic hydrocarbon solvent) and 9.18 parts by mass of mineral spirits were added. This was heated and stirred, and after reaching 100 ° C., to 2.27 parts by mass of styrene, 9.03 parts by mass of tertiary butyl methacrylate, 3.17 parts by mass of 2-ethylhexyl methacrylate, and 2-ethyl acrylate. A mixture obtained by mixing 5.01 parts by mass of xylyl and 0.22 parts by mass of tertiary butyl peroxy-2-ethylhexanoate in advance was added dropwise over 3 hours and stirred for 3 hours to obtain a first mixture. .

(Second step)
After completion of dropping, 0.22 parts by mass of tertiary butyl peroxy-2-ethylhexanoate and 0.22 parts by mass of mineral spirits were previously added to the first mixture obtained in the first step while maintaining 100 ° C. The mixture obtained by mixing was added dropwise over 1 hour, and further stirring was continued at 100 ° C. for 2.5 hours. Then, 10.45 parts by mass of Solvesso 100 was added and stirred to obtain a second mixture.

(Third step)
While maintaining 100 ° C., 6.40 parts by mass of styrene, 9.26 parts by mass of methyl methacrylate, 12.02 parts by mass of ethyl acrylate, 2-hydroxylethyl methacrylate, in the second mixture obtained in the second step. 5.00 parts by mass, 1.32 parts by mass of methacrylic acid and 0.65 parts by mass of tertiary butyl peroxy-2-ethylhexanoate were added dropwise over 4 hours while stirring with heating. A third mixture was obtained.

(4th process)
After completion of dropping, while maintaining the temperature at 100 ° C., 0.65 parts by mass of tertiary butyl peroxy-2-ethylhexanoate and 0.65 parts by mass of mineral spirits, Solvesso in the third mixture obtained in the third step 100.30 parts by mass of a mixture obtained in advance was added dropwise over 1.5 hours, and further stirred at 100 ° C. for 2.5 hours, then 11.75 parts by mass of Solvesso 100 and mineral spirits 7. 40 parts by mass was added and stirred to obtain an acrylic resin dispersion.
The acrylic resin dispersion was a dispersion of a resin having a carboxyl group as a “organic functional group capable of reacting with an amino group” and a hydroxyl group in the molecule.
The resin solid content of the acrylic resin dispersion was 55.0% by mass.
The hydroxyl value of the solid content in the acrylic resin dispersion is 39.2 mgKOH / g, the acid value is 15.7 mgKOH / g, the carboxyl group equivalent is 3584 g / eq, the number average molecular weight in terms of polystyrene is 8700, the weight in terms of polystyrene The average molecular weight was 121300. The resin solid content of the resin dispersion, the hydroxyl value of the resin solid, the acid value, the carboxyl group equivalent, the polystyrene-equivalent number average molecular weight, the polystyrene-equivalent weight average molecular weight, the organic functional group capable of reacting with an amino group, Table 4 shows the number of organic functional groups that can react with amino groups.
The acrylic resin dispersion had a polystyrene-reduced weight average molecular weight of 121300 in the resin solid content, and did not correspond to the component (B) of the present invention.

  In Table 4, the amount of each component used is shown in parts by mass.

1-3. Preparation example of resin solution (resin solution 1-26), which is a reaction product (resin composition for paint) of component (A) and component (B) According to the preparation example shown below, resin solutions 1-26 are synthesized. did.

1-3-1. Resin solution 1
(First step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a water separator, etc., 94.10 parts by mass of acrylic resin solution A and KF-8010 (manufactured by Shin-Etsu Chemical Co., Ltd., both end amino-modified polydimethylsiloxane) Type silicone oil) 3.10 parts by mass were added, and the mixture was heated and stirred at reflux temperature to confirm a predetermined amount of dehydration to obtain a first mixture.

(Second step)
Into the first mixture obtained in the first step, 2.80 parts by mass of mineral spirits were added and stirred and cooled to obtain a resin solution 1. In addition, the resin solid content of the resin solution 1 was 55.0 mass%, and the solid content hydroxyl value of the resin solution 1 was 37.6 mgKOH / g.

1-3-2. Resin solution 2, 12-19, 22, 23, 26
Resin solutions were prepared in the same manner as in the resin solution 1 except that the compounds shown in Table 5 and the amounts used were changed. In addition, the organic functional group of the component (B) used in the reaction, the resin solid content of the resin solution, the hydroxyl value, acid value, active hydrogen value (NH value) in the resin solid content, and the corresponding resin composition for paint Table 5 shows (described later).

1-3-3. Resin solution 3
(First step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, etc., 92.98 parts by mass of an acrylic resin solution U and 3.71 parts by mass of DC3055 (manufactured by Dow Corning Corp., amino group-containing silicone resin) were added. The mixture was heated and stirred at 0 ° C. for 6 hours to obtain a first mixture.

(Second step)
Into the first mixture obtained in the first step, 3.31 parts by mass of mineral spirit was added and stirred and cooled to obtain a resin solution 3. In addition, the resin solid content of the resin solution 3 was 55.0 mass%, and the solid content hydroxyl value of the resin solution 3 was 37.3 mgKOH / g.

1-3-4. Resin solution 4
(First step)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and the like, 92.98 parts by mass of acrylic resin solution B and 3.71 parts by mass of DC3055 (manufactured by Dow Corning Corp., amino group-containing silicone resin) were added. The mixture was heated and stirred at 0 ° C. for 2 hours to obtain a first mixture.

(Second step)
Into the first mixture obtained in the first step, 3.31 parts by mass of mineral spirit was added and stirred and cooled to obtain a resin solution 4. In addition, the resin solid content of the resin solution 4 was 55.0 mass%, and the solid content hydroxyl value of the resin solution 4 was 40.8 mgKOH / g.

1-3-5. Resin solutions 5-11, 21
Resin solutions were prepared in the same manner as in the resin solution 4 except that the compounds shown in Table 5 and the amounts used were changed. In addition, the organic functional group of the component (B) used for the reaction, the resin solid content of the resin solution, the hydroxyl value in the resin solid content, the active hydrogen value (NH value), and the corresponding resin composition for coating (described later) Is shown in Table 5.

1-3-6. Resin solution 20
In a container equipped with a stirrer, 94.10 parts by mass of acrylic resin solution Q and 3.10 parts by mass of KF-8010 (manufactured by Shin-Etsu Chemical Co., Ltd., both terminal amino-modified polydimethylsiloxane type silicone oil) are added, and minerals are added. Spirit 2.80 mass parts was added and stirred, and the resin solution 20 was obtained. The resin solid content of the resin solution 20 is 55.0% by mass, the solid content hydroxyl value of the resin solution 20 is 38.4 mgKOH / g, and the solid content active hydrogen value (NH value) is 14.7 mgKOH / g. there were.

1-3-7. Resin solution 24
In a container equipped with a stirrer, 55.00 parts by mass of KF-8012 (manufactured by Shin-Etsu Chemical Co., Ltd., both end amino-modified polydimethylsiloxane type silicone oil) was added, and 45.00 parts by mass of mineral spirits were added and stirred. As a result, a resin solution 24 was obtained. The resin solid content of the resin solution 24 was 55.0% by mass, and the solid content active hydrogen value (NH value) of the resin solution 24 was 51.0 mgKOH / g.

1-3-8. Resin solution 25
100.00 parts by mass of the acrylic resin solution M was used as it was, and called the resin solution 25. In addition, the resin solid content of the resin solution 25 was 55.2 mass%, and the solid content hydroxyl value of the resin solution 25 was 39.9 mgKOH / g.

  In Table 5, the amount of each component used is shown in parts by mass.

2. Preparation of coating composition (Example 1)
Resin solution 1 54.48 parts by mass, colored pigment JR-806 (manufactured by Teika Co., Ltd., titanium oxide) 27.20 parts by mass, extender pigment BARIACE B-30 (manufactured by Sakai Chemical Industry Co., Ltd., precipitated barium sulfate) 9.80 parts by mass and viscosity modifier Disparon D6820-20M (Made by Kajimoto Kasei Co., Ltd., amide-based viscosity modifier mineral spirit / benzyl alcohol mixed solution, solid content 20% by mass) mixed with 4.42 parts by mass After that, dispersion processing was performed for 2 hours with a sand grinder to prepare a main agent. And just before coating, with respect to the main component of 95.90 parts by mass, paint curing agent Duranate TSA-100 (manufactured by Asahi Kasei Chemicals Corporation, weak solvent soluble hexamethylene diisocyanate polyisocyanate (isocyanurate type of hexamethylene diisocyanate) Compound)) 4.10 parts by mass were added and mixed to obtain a coating composition of Example 1.

(Examples 2-13, Comparative Examples 1-13)
Coating compositions of Examples 2 to 13 and Comparative Examples 1 to 13 were prepared in the same manner as in the production procedure of Example 1 except that the types and blending amounts of various components were changed as shown in Table 6.

  In Table 6, the amount of each component used is shown in parts by mass.

3. Coating plate production A coating composition (Examples 1 to 13 and Comparative Examples 1 to 13) shown in Table 6 is applied to a sandblasted steel plate having a thickness of 3.2 mm and a size of 70 × 150 mm so that the dry film thickness becomes 80 μm. After spray coating, the coating composition was dried at room temperature (20 ° C.) for 1 week to prepare coated plates of Examples 1 to 13 and Comparative Examples 1 to 13. About the produced coating board, the coating-film performance was evaluated by the test shown below. Table 7 shows the evaluation results.

<Evaluation of paint workability>
The coating workability at the time of creating the painted plate was visually judged according to the following criteria.

(Criteria)
○: Spray atomization is good and there is no abnormality on the coating surface.
X: Spray atomization is insufficient, and the number of sprays for obtaining a predetermined film thickness increases. Abnormalities such as repellency are observed on the surface of the coating film.

  The coating compositions of Examples 1 to 13 showed good coating workability (Table 7). Therefore, the resin composition for paint of the present invention can provide a paint excellent in painting workability.

<Low temperature storage stability test>
Only the paint main component of Table 6 containing no curing agent prepared in Examples 1 to 13 and Comparative Examples 1 to 13 was sealed in a metal can having a capacity of 300 mL and an inner diameter of 70 to 80 mm and sealed at 5 ° C. After storage for 1 month, the low temperature storage stability test was evaluated based on the following criteria.

(Criteria)
◯: Significant differences in the state in the container after storage, the appearance of the coating film when subjected to coating, and the coating workability are not recognized as compared with those before storage.
X: Significant differences are seen in the state in the container after storage, the appearance of the coating film when subjected to coating, and the coating workability compared to before storage.

<High temperature storage stability test>
Only the paint main ingredient component of Table 6 which does not contain the curing agent prepared in Examples 1 to 13 and Comparative Examples 1 to 13 was sealed in a metal can having a capacity of 300 mL and an inner diameter of 70 to 80 mm. After storage for 1 month, the low temperature storage stability test was evaluated based on the following criteria.

(Criteria)
○: No significant difference is observed in the state in the container after storage, the appearance of the coating film when it is used for coating, and the coating workability compared to before storage.
X: Significant differences are seen in the state in the container after storage, the appearance of the coating film when subjected to coating, and the coating workability compared to before storage.

  The paint main component (paint resin composition) used in the paint compositions of Examples 1 to 13 showed good storage stability at both low and high temperatures (Table 7). Therefore, the resin composition for paints of the present invention is excellent in storage stability.

<Accelerated weather resistance test>
An accelerated weather resistance test was conducted for 4000 hours using a xenon arc lamp type tester in accordance with JIS K 5600-7-7. The glossiness of the coating film after the test was compared with the initial coating film for which the accelerated weather resistance test was not performed, and the determination was made based on the following criteria using visual inspection and a gloss meter.

(Criteria)
◎ +: No change in coating film appearance, gloss retention of 95% or more ◎: No change in coating film appearance, gloss retention of 90% or more and less than 95% ○: slight change in coating film appearance, gloss retention 80% or more and less than 90% ×: The change in the appearance of the coating film is significant, and the gloss retention is less than 80%

  The coating films formed from the coating compositions of Examples 1 to 13 showed excellent weather resistance. (Table 7). Therefore, the resin composition for paints of the present invention can provide a paint capable of forming a coating film excellent in weather resistance.

  In the following paint evaluation tests, painted plates were prepared for each test and evaluated.

<Surface drying test>
The coating composition is air-sprayed onto a sandblasted steel sheet having a thickness of 3.2 mm and a size of 70 × 150 mm so that the dry film thickness is 80 μm, and the ambient temperature (20 ° C.) is 10% humidity and 90% humidity. After drying, the time until the obtained coating film reached the dry-to-touch state specified in JIS K 5500 “Paint term” was measured, and the surface drying property was evaluated based on the following criteria.

(Criteria)
○: Time to dry to touch within 90 minutes ×: Time to dry to touch exceeds 90 minutes

  The coating compositions of Examples 1 to 13 exhibited good surface drying properties (curability) at both low humidity and high humidity (Table 7). Therefore, the resin composition for coatings of the present invention can provide a curable coating without being affected by ambient humidity conditions.

<Appearance evaluation of coating film>
The coating composition was applied to a sandblasted steel plate having a thickness of 3.2 mm and a size of 70 × 150 mm with a brush so that the wet film thickness was 300 μm, and the obtained coating film was dried at room temperature (20 ° C.) for 1 week. After that, the appearance of the coating film was evaluated based on the following criteria.

(Criteria)
○: Abnormalities such as gloss, cracks, and peeling are not observed on the appearance of the coating film.
X: Abnormalities such as glossing, cracking and peeling are recognized in the appearance of the coating film.

  The coating films formed from the coating compositions of Examples 1 to 13 exhibited an excellent appearance with no abnormalities such as glossiness, cracking and peeling (Table 7). Therefore, the resin composition for paints of the present invention can provide a paint that is difficult to cure and shrink and has high substrate followability.

<Weight drop resistance test>
The coating composition is air spray-coated on a hot-dip galvanized steel sheet having a thickness of 0.6 mm and a size of 200 × 100 mm so that the dry film thickness becomes 80 μm, and the obtained coating film is at room temperature (20 ° C.) for one week. After drying, among the methods specified in JIS K 5600-5-3, when using a 500 g weight in the 3.3 “DuPont” test and dropping from a height of 30 cm, based on the following criteria: The weight drop resistance was evaluated.

(Criteria)
○: No cracking or peeling of the coating film due to impact deformation of the test piece.
X: The crack of the coating film by the impact deformation of a test piece and peeling are recognized.

  The coating films formed from the coating compositions of Examples 1 to 13 were excellent in impact resistance (Table 7). Therefore, the resin composition for paints of the present invention can provide a paint having excellent coating film strength.

  The present invention can be used in the field of paints.

Claims (6)

A resin composition for paint,
The coating resin composition includes a reaction product of the following (A) and (B):
(A) An organopolysiloxane compound having two or more amino groups in the molecule but not containing -Si-OH group and -Si-OC- group, and having an amine equivalent of 300 to 6000 g / eq. An organopolysiloxane compound,
(B) a resin having an organic functional group capable of reacting with an amino group and a hydroxyl group in the molecule, a weight average molecular weight of 3000 to 100,000, and a hydroxyl value of 10 to 200 mgKOH / g;
The reaction product has a hydroxyl group in the molecule;
The reaction product forms a coating film by reaction with an isocyanate compound;
Resin composition for paint.   The resin composition for coatings according to claim 1, wherein the siloxane bond in the organopolysiloxane compound (A) includes one or more three-way branched structures (T structures).   3. The coating resin composition according to claim 1 or 2, wherein the organic functional group (B) is an epoxy group.   The reaction product of (A) and (B) further has an amino group in the molecule, and the resin composition for paints according to any one of claims 1 to 3.   The coating material containing the resin composition for coating materials of any one of Claims 1-4.   An article coated with the paint according to claim 5.