JP2801504B2 - Curable resin composition, coating composition and coating film forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable resin composition which can be suitably used as a top coating for automobiles and a coating for coil coating, and a coating composition containing this resin as a main component.

[0002]

2. Description of the Related Art It is common to use a combination of a hydroxyl group-containing polymer and a melamine resin curing agent as a binder used as a top coating for automobiles. However, a cured coating film obtained by using such a melamine resin as a curing agent tends to be easily etched by an acid. Therefore, it has been desired to improve the acid resistance.

[0003] On the other hand, in recent years, there has been a demand for a high solid paint which emits a small amount of solvent into the atmosphere in order to reduce adverse effects on the environment.

[0004] It is considered that the coating film obtained by using a melamine resin as a curing agent tends to be easily etched by an acid, due to a triazine nucleus in the melamine resin. Therefore, it is considered that it is difficult to significantly improve acid resistance as long as a melamine resin is used as a curing agent.

In order to solve this drawback, the present inventors have proposed a novel coating composition which does not use a melamine resin in JP-A-2-45577 and JP-A-3-287650. A similar coating composition is described in U.S. Pat.
No. 3399109 (Zimmerman)
And 3,528,935 (Marion et al.). Such a coating composition has good acid resistance because it has an ester bond formed by reacting an acid group and an epoxy group as a crosslinking point, and also has sufficient weather resistance as a top coat for automobiles. However, since the curing system has a high functional group concentration and a high viscosity, it is difficult to obtain a high solid type high solid paint, and a reduction in the amount of solvent is desired from the viewpoint of environmental regulations.

JP-A-2-64181 discloses a coating resin composition containing a polysiloxane having a hydroxyl group and a crosslinking agent which reacts with the hydroxyl group.
JP-A 1-138228 discloses a method for producing a polysiloxane having a hydroxyl group. However, the paint disclosed in this application has a problem that it is inferior in acid resistance and abrasion resistance as an automotive topcoat.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a coating film having excellent resistance to acid rain and excellent scratch resistance. It is to provide a solid content curable resin composition and a coating composition.

[0008]

The present invention relates to (a) (i) a hydroxyl-containing silicone polymer, preferably a compound represented by the formula:

[0009]

Embedded image

Wherein R ¹ is a methyl, phenyl or phenylethyl group, and R ² and R ³ are independently methyl, phenyl, phenylethyl, 3-hydroxypropyl or 3- (hydroxyethoxy) propyl a group, R ⁴ is methyl, 3-hydroxypropyl or 3- (hydroxyethoxy) propyl group, R ⁵ is methyl, phenyl, phenylethyl or isobutyl group, l is an integer of from 1 to 20, m is an integer of 2 to 4, and n is an integer of 0 to 2. ] In one molecule of at least one selected from the group consisting of compounds having a structure represented by the following formula:
A hydroxyl-containing silicone polymer having one hydroxyl group,
(ii) an acid anhydride group-containing compound, obtained by subjecting the hydroxyl group and the acid anhydride group to a half-esterification reaction in an amount of 1 / 1.0 to 1 / 0.2, having a hydroxyl group and a carboxyl group (B) (i) (1) an acid anhydride group-containing ethylenically unsaturated monomer 15
To 40% by weight and (2) 60 to 85% by weight of another copolymerizable ethylenically unsaturated monomer to obtain (ii) a polymer having 1 to 12 carbon atoms. Having a carboxyl group and a carboxylate group, which are obtained by reacting a hydroxyl group-containing compound containing atoms with an acid anhydride group and a hydroxyl group in a molar ratio of 1 / 1.5 to 1/1 in a molar ratio. 20-60% by weight of polymer; and (c) (i)

[0011]

Embedded image

[Wherein, R is a hydrogen atom or a methyl group, m is an integer of 2 to 8, n is an integer of 3 to 7,
q is an integer of 0-4. 5 to 40% by weight of a hydroxyalkyl (meth) acrylate having a structure represented by the formula: (ii)
A hydroxyl group obtained by copolymerizing 10 to 60% by weight of an epoxy group-containing ethylenically unsaturated monomer and optionally (iii) 0 to 85% by weight of another copolymerizable ethylenically unsaturated monomer; The present invention provides a curable resin composition containing 30 to 60% by weight of a polymer containing an epoxy group, thereby achieving the above object.

A silicone polymer having a hydroxyl group and a carboxyl group, which is one component of the curable resin composition of the present invention.
(a) is obtained by subjecting a hydroxyl group-containing silicone polymer (a) (i) and an acid anhydride group-containing compound (a) (ii) to a half-esterification reaction.

The method for producing the hydroxyl group-containing silicone polymer (a) (i) which can be used in the present invention is described in the 1990 Symposium on Organosilicon Materials Chemistry, pp. 29-30. Some of these are commercially available, for example, Shin-Etsu Silicone KR-2001 and Nippon Unicar NVC shown in the following formula
-Silicone series.

[0015]

Embedded image

The hydroxyl-containing silicone polymer (a) (i)
Preferably has an average of 3 to 12 hydroxyl groups in one molecule. If the average number of hydroxyl groups contained in one molecule of the hydroxyl group-containing silicone polymer (a) (i) is less than 3, the curability becomes insufficient, and if it exceeds 12, the viscosity increases and the nonvolatile content decreases.

The compound containing an acid anhydride group which can be used in the present invention
(a) and (ii) are not particularly limited as long as they are compounds that provide carboxy functionality by reacting with hydroxyl groups under ordinary reaction conditions such as room temperature to 120 ° C. and normal pressure. here,
It is preferable to use an acid anhydride group-containing compound having a cyclic (unsaturated or saturated) group having 8 to 12 carbon atoms.
This is because the compatibility of the resin is better when such a compound is used. Specific examples of preferred acid anhydride group-containing compound (a) (ii) include hexahydrophthalic anhydride, phthalic anhydride,
Examples include 4-methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride, and trimellitic anhydride.

The half esterification reaction between the hydroxyl group-containing silicone polymer (a) (i) and the acid anhydride group-containing compound (a) (ii) is carried out according to a conventional method, for example, at room temperature to 120 ° C. for 30 minutes. ~ 8 hours. If the reaction is carried out for a long time under a violent condition such as exceeding 120 ° C., a polyesterification reaction occurs to produce a high molecular weight silicone polyester. Such a silicone polyester is not preferable for use in the present invention because it has a small number of functional groups and has a high viscosity. The reaction ratio is 1 / 1.0 between the hydroxyl group and the acid anhydride group.
It is preferable to carry out the reaction in an amount of a ratio of 1/1 / 0.2. If this ratio exceeds 1 / 0.2, the water resistance becomes poor, and if it is less than 1 / 1.0, an excess of acid anhydride remains in the system, which is not preferable because side reactions occur when used in paints.

The thus obtained silicone polymer having a hydroxyl group and a carboxyl group is 500 to 6000,
In particular, it is preferable to have a number average molecular weight Mn in the range of 1,000 to 4,500. When the number average molecular weight exceeds 6000, the viscosity increases and the non-volatile content decreases, and when the number average molecular weight is less than 500, the curability becomes insufficient. The silicone polymer having a hydroxyl group and a carboxyl group preferably has an acid value in the range of 20 to 180, particularly 35 to 150, and a hydroxyl value in the range of 2 to 120, particularly 10 to 80. In particular, when the acid value is less than 20, the curability becomes insufficient, and when the acid value is more than 180, the nonvolatile content decreases. In addition,
The molecular weight of the polymer used in the present invention is determined by the GPC method.

Polymer having a carboxyl group and a carboxylic ester group used in the curable resin composition of the present invention
(b) is a half ester group-containing polymer obtained by reacting an acid anhydride group-containing polymer (b) (i) with a hydroxyl group-containing compound (b) (ii).

The acid anhydride group-containing polymer (b) (i) is used in an amount of 15 to 40% by weight, preferably 15 to 30% by weight, of the ethylenically unsaturated monomer (b) (i) (1) having an acid anhydride group. It is obtained by copolymerizing another copolymerizable ethylenically unsaturated monomer (b) (i) (2) with 60 to 85% by weight, preferably 70 to 85% by weight. Acid anhydride group-containing ethylenically unsaturated monomer (b) (i)
If the amount of (1) is less than 15% by weight, the curability will be insufficient, and if it exceeds 40% by weight, the resulting coating film will be too hard and brittle, and the weather resistance will be insufficient.

Acid anhydride group-containing ethylenically unsaturated monomer
Specific examples of (b) (i) (1) include itaconic anhydride, maleic anhydride and citraconic anhydride. The other copolymerizable ethylenically unsaturated monomer (b) (i) (2) is not particularly limited as long as it does not adversely affect the acid anhydride group,
It is preferably a monomer having one ethylenically unsaturated bond and having 3 to 15 carbon atoms, particularly 2 to 12 carbon atoms.

A mixture of two or more ethylenically unsaturated monomers to form another copolymerizable ethylenically unsaturated monomer (b)
(i) It is also possible to use as (2). This is because it is effective for improving the compatibility between the resins. Specific examples of such a monomer that can be suitably used include, as ethylenically unsaturated monomers, styrene, α-methylstyrene, (meth)
Acrylic esters (e.g., (meth) methyl acrylate, (meth) ethyl acrylate, (meth) propyl acrylate, (meth) acrylic acid-n, i, and t-butyl, (meth)
2-ethylhexyl acrylate and lauryl (meth) acrylate, cyclohexyl (meth) acrylate), VeoVa-9 and VeoVa-10 manufactured by Shell Inc., and the like. Monomers having a carboxyl group such as acrylic acid and methacrylic acid may also be used. When styrene is used as another copolymerizable monomer, it is particularly preferred to use it in an amount of 5 to 40% by weight.

The copolymerization is carried out by a known method such as solution polymerization such as radical polymerization.
The reaction can be carried out at 100 to 150 ° C. for a polymerization time of 3 to 8 hours.
As the initiator, an azo-based or peroxide-based initiator is suitably used. Other additives such as chain transfer agents may also be used. The number average molecular weight of the obtained polymer is 1500 to 80
00, particularly preferably 2000 to 5000. When the number average molecular weight exceeds 8000, the polymer viscosity becomes high, so that it becomes difficult to prepare a coating composition having a high solid content. Number average molecular weight is 15
If it is less than 00, the curability of the curable resin composition becomes insufficient. The resulting polymer has an average of at least 2 per molecule.
And preferably 2 to 15 acid anhydride groups. When the number of the acid anhydride groups contained in one molecule is less than 2, the curability of the curable resin composition becomes insufficient. If it exceeds 15, it becomes too hard and brittle, and the weather resistance is insufficient.

Next, the obtained polymer is prepared by mixing an acid anhydride group and a hydroxyl group in a molar ratio of 1 / 1.5 to 1/1, preferably 1/1.
The polymer (b) having a carboxyl group and a carboxylate group is prepared by reacting with the hydroxyl group-containing compound (b) (ii) in an amount of 5 to 1/1/3. If it exceeds 1 / 1.5, there will be too much excess alcohol, which will cause cracking during curing. If it is less than 1/1, unreacted anhydride groups will remain.
Poor storage stability.

The hydroxyl group-containing compound (b) (i
i) is a low molecular weight compound having 1 to 12, preferably 1 to 8 carbon atoms. This is because the alcohol volatilizes during heating and is good for regenerating the acid anhydride group. Hydroxyl-containing compounds that can be suitably used include methanol, ethanol,
Examples include n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, methyl cellosolve, ethyl cellosolve, dimethylaminoethanol, diethylaminoethanol, acetol, allyl alcohol, and propargyl alcohol. Particularly preferred are acetol, allyl alcohol, propargyl alcohol and methanol.

The polymer (c) having a hydroxyl group and an epoxy group used in the resin composition of the present invention preferably has an average of 2 to 10, more preferably 3 to 8, epoxy groups in one molecule.
And preferably 2 to 12, more preferably 4 to 10 hydroxyl groups on average. Also, the epoxy equivalent is preferably 100 to 800, more preferably 200 to 600, and the hydroxy equivalent is preferably 200 to 1200, more preferably 400 to 600.
1000. If the epoxy equivalent is larger than the above upper limit, the curability of the curable resin composition will be insufficient. On the other hand, if it is smaller than the lower limit, the film becomes too hard and the coating film becomes brittle. If the hydroxy equivalent is less than 200, the water resistance of the cured coating film is not sufficient, and if it exceeds 1200, the curability is not sufficient, which is not preferable.

Such a polymer (c) has the formula

[0029]

Embedded image

[Wherein, R is a hydrogen atom or a methyl group, m is an integer of 2 to 8, n is an integer of 3 to 7,
q is an integer of 0-4. 5 to 40% by weight, preferably 15 to 30% by weight, an epoxy group-containing ethylenically unsaturated monomer (c) (ii) 10 to 60% by weight having a structure represented by the following formula: %, Preferably 15 to 50% by weight, and optionally other copolymerizable ethylenically unsaturated monomers (c) (iii) 0 to 85% by weight, preferably 10 to 50% by weight.
60% by weight. If the hydroxyalkyl (meth) acrylate is less than 5% by weight, the curability is insufficient, and if it is more than 40% by weight, the compatibility is insufficient, so that the reaction does not proceed sufficiently. If the amount of the epoxy group-containing ethylenically unsaturated monomer is less than 10% by weight, the curability will be insufficient, and if it is more than 60% by weight, it will be too hard and insufficient weather resistance.

Polymer having a hydroxyl group and an epoxy group
The hydroxyalkyl chain of the hydroxyalkyl (meth) acrylate (c) (i) that can be used to prepare (c) is too hard, because the flexibility near the cross-linking point is lost if it is too short, and it is too hard if it is too long. Intermolecular weight becomes too large. Therefore, it preferably has 4 to 20 carbon atoms, and more preferably 4 to 10 carbon atoms. Specifically, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and their reaction products with ε-caprolactone, and ε-caprolactone of 2-hydroxyethyl (meth) acrylate Compounds such as the reactants of Such compounds are commercially available, for example, 4-hydroxybutyl acrylate of `` 4HBA '' manufactured by Mitsubishi Chemical Corporation, `` Placcel FM1 '' manufactured by Daicel Chemical Industries, Ltd., `` Placcel FA1 '' and the like. Can be And "4HBM
A ", 4-hydroxybutyl methacrylate and the like.
Alternatively, such compounds can be prepared by esterifying (meth) acrylic acid with a large excess of diols (eg, 1,4 butanediol, 1,6 hexanediol).

Examples of the monomers (c) and (ii) include glycidyl (meth) acrylate and 3,4-epoxycyclohexanylmethyl (meth) acrylate. As other monomers (c) (iii), `` other copolymerizable ethylenically unsaturated monomers (b) (i) (2) to prepare the acid anhydride group-containing polymer (b) (i) "Include the above-mentioned monomers.

The copolymerization is carried out by a known method such as solution polymerization such as radical polymerization.
The reaction can be carried out at 100 to 150 ° C. for a polymerization time of 3 to 8 hours.
As the initiator, peroxide-based and azo-based initiators are suitably used. Further, the radical polymerization initiator is preferably used in an amount of 3 to 15% by weight based on all monomers. A chain transfer agent or the like may be added to the monomer composition as other additives. The resulting polymer has a molecular weight
It is preferably from 500 to 8000, particularly preferably from 1500 to 5000.

The thus obtained silicone polymer having a hydroxyl group and a carboxyl group (a), a polymer having a carboxyl group and a carboxylic ester group (b),
The curable resin composition of the present invention can be obtained by blending a polymer (c) containing a hydroxyl group and an epoxy group.

The compounding ratio is such that the molar ratio between the carboxyl groups contained in the polymers (a) and (b) and the epoxy groups contained in the polymer (c) is 1 / 1.2 to 1 / 0.6, preferably 1 / 1.0. ~ 1
/0.8, and the carboxyl group or carboxylic ester group contained in the polymer (b) and the polymer (a) and
It is preferable to carry out the reaction in an amount such that the molar ratio with the hydroxyl group contained in (c) is 1 / 1.5 to 1 / 0.3, particularly 1 / 1.2 to 1 / 0.5.

When the ratio of the carboxyl group contained in the polymers (a) and (b) to the epoxy group contained in the polymer (c) exceeds 1 / 0.6, the curability of the obtained resin composition decreases, If it is less than 1 / 1.2, the coating film turns yellow. Polymer (b)
When the molar ratio of the carboxyl group or carboxylic acid ester group contained in the polymer to the hydroxyl group contained in the polymers (a) and (c) exceeds 1 / 0.3, the curability of the obtained resin composition decreases, If the ratio is less than 1.5, the hydroxyl group becomes excessive, so that the water resistance decreases.

Such a blending amount can be calculated from the hydroxyl value, acid value and epoxy equivalent of each polymer by a calculation method well known to those skilled in the art. The curable resin composition of the present invention generally comprises (a) 5 to 50, preferably 8 to 40% by weight of a silicone polymer having a hydroxyl group and a carboxyl group, and (b) a polymer having a carboxyl group and a carboxylic ester group. 20-60, preferably 30-50% by weight, and (c) a polymer 30-6 containing hydroxyl and epoxy groups
It is obtained by blending in an amount of 0, preferably 30 to 50% by weight. When the amount of the polymer (a) is more than 50% by weight, the coating film becomes too soft and the acid resistance is reduced. When the amount is less than 5%, the scuff resistance is deteriorated. If the amount of the polymer (b) is less than 20% by weight, the acid resistance decreases, and if it is more than 60% by weight, the coating film becomes too hard. The amount of the polymer (c) is adjusted so as to be compatible with the total amount of the acid groups contained in the system. Therefore, if the amount is less than the amount corresponding to the acid groups, the curability is reduced, and if the amount is too large, yellowing resistance is deteriorated.

The curing mechanism of the curable resin composition of the present invention thus obtained is as follows.
The carboxyl group and the carboxylic acid ester group in the reaction react with each other to generate an acid anhydride group in the polymer (b), and a free hydroxyl group-containing low molecular weight compound is generated. The generated hydroxyl group-containing low molecular weight compound is removed from the system by evaporation.
The acid anhydride group formed in the polymer (b) reacts with the hydroxyl group contained in the polymer (a) and the polymer (c) to form a cross-linking point and form an acid group again. The acid group and the carboxyl group contained in the polymer (a) react with the epoxy group contained in the polymer (c) to form a crosslinking point. As described above, the curing progresses as the three types of polymers react with each other.

With such a structure, it is possible to provide a high crosslinking density by reacting the three kinds of polymers with each other. In addition, the Si-O-Si bond of the polymer (a) component has a high degree of freedom in rotational motion and has a low free energy of rotation, thereby providing a low-viscosity resin composition. It is presumed that the rate increases and performance such as scratch resistance is exhibited.

In addition to the above-mentioned polymers (a), (b) and (c), the curable resin composition of the present invention is usually used in the esterification reaction between an acid such as a quaternary ammonium salt and epoxy. It may include the curing catalyst used. Specific examples of other catalysts that can be used in the curable resin composition of the present invention include benzyltriethylammonium chloride or bromide, tetrabutylammonium chloride or bromide, salicylate or glycolate, and paratoluenesulfonate. These catalysts may be used as a mixture. The compounding amount of this catalyst is 0.
1-2.0% by weight is preferred. Further, as described in JP-A Nos. 2-151651 and 2-279713, a tin-based compound may be used in combination therewith. Tin catalysts include
For example, dimethyltin bis (methylmalate), dimethyltinbis (ethylmalate), dimethyltinbis (butylmalate), dibutyltinbis (butylmalate) and the like can be mentioned. The weight ratio between the curing catalyst and the tin compound is 1/4 to 1 /
0.2 is preferred.

In order to increase the crosslinking density and improve the water resistance, a melamine / formaldehyde resin and / or a blocked isocyanate may be added to the resin composition of the present invention. In order to improve the weather resistance of the coating film, an ultraviolet absorber, a hindered amine light stabilizer, an antioxidant and the like may be added. Further, crosslinked resin particles as a rheology control agent or a surface conditioner for adjusting the appearance may be added. Furthermore, solvents such as alcohol solvents (eg, methanol, ethanol, propanol, and butanol), hydrocarbon solvents, and ester solvents may be used as diluents for viscosity adjustment and the like.

The resin used in the present invention has an acid group as a functional group. Accordingly, an aqueous resin composition using water as a medium can be obtained by neutralizing with an amine.

The curable resin composition of the present invention is suitably used as a clear coating composition. In this case, a color pigment-containing aqueous paint or a color pigment-containing organic solvent-type paint is preferably used as the base paint. At the time of coating, a two-coat, one-bake curing method in which both coating films are cured after applying a clear coating material containing the curable resin composition of the present invention on the base coating surface without curing the base coating material is preferably used. Can be

However, when an aqueous paint is used,
In order to obtain a good-finished coating film, it is preferable to heat the base coat at 60 to 100 ° C. for 2 to 10 minutes before applying the clear paint. As the base paint, those specifically described in US Pat. Nos. 5,151,125 and 5,183,504 can be used. In particular, U.S. Pat.
The water-based coating composition described in No. 4 is most suitable in terms of finish, appearance and performance.

The method for producing the curable resin composition of the present invention is not particularly limited, and any method known to those skilled in the art can be used. For example, in the case of using an enamel coating, a compound such as a pigment may be kneaded and dispersed using a kneader or a roll.

The coating composition of the present invention can be applied by spray coating, brush coating, dip coating, roll coating, flow coating, or the like. The substrate may be primed or semi-coated, if desired. Known undercoating and intermediate coatings can be used.

The coating composition of the present invention can be advantageously used on any substrate, such as wood, metal, glass, cloth, plastic, foam and the like, especially on plastic and metal surfaces such as steel, aluminum and alloys thereof.

In general, the thickness will vary depending on the desired application. In many cases, 0.5 to 3 mils is useful.

After coating on the substrate, the coating is cured. Curing is performed at 100 to 180 ° C, preferably 120 to 160 ° C, to obtain a cured coating film having a high degree of crosslinking. Although the curing time varies depending on the curing temperature and the like, curing at 120 ° C. to 160 ° C. for 10 to 30 minutes is appropriate.

[0050]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Unless otherwise specified, the amounts are given in parts by weight.

[0051]

Preparation Examples 1 to 10 Preparation examples 1 to 10 explain the preparation of a silicone polymer having a hydroxyl group and a carboxyl group used in the curable resin composition of the present invention.

Preparation Example 1 140 parts of butyl acetate were placed in a 2 liter reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a dropping funnel.

[0053]

Embedded image

KR-2001 manufactured by Shin-Etsu Silicone Co., Ltd.
Of 1088 parts and 370 parts of hexahydrophthalic anhydride were charged, the temperature was raised to 125 to 130 ° C., and the mixture was reacted for 2 hours. After confirming the disappearance of the absorption of the acid anhydride group by IR analysis, 206 parts of butyl acetate was added to obtain a colorless and transparent varnish. The obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter referred to as polymer AI) had a nonvolatile content of 80% and an acid value of 95 mgKOH / g solid.

Preparation Examples 2 to 4 A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the formulations shown in Table I below were used. Table I shows the nonvolatile content and the acid value of each of the obtained silicone polymers having a hydroxyl group and a carboxyl group (hereinafter, referred to as polymers A-II to A-IV, respectively).

Preparation Example 5 Formula

[0057]

Embedded image

Wherein Me is a methyl group, Ph is a phenyl group, iBu is an isobutyl group, and A is 3-
(Hydroxyethoxy) propyl group. A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the silicone polymer having the structure shown in Table I was used and the composition shown in Table I below was used. Table I shows the nonvolatile content and the acid value of the obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter, referred to as polymer AV).

Preparation Example 6 Formula

[0060]

Embedded image

[Wherein, Me, Ph, iBu and A are as defined above. Using a silicone polymer with the structure shown in
A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the formulations shown in Table I below were used. Table I shows the nonvolatile content and the acid value of the obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter, referred to as polymer A-VI).
Shown in

Preparation Example 7 Formula

[0063]

Embedded image

[Wherein, Me, Ph, iBu and A are as defined above. Using a silicone polymer having the structure shown in
A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the formulations shown in Table I below were used. The nonvolatile content and the acid value of the obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter, referred to as polymer A-VII) are shown.
Shown in I.

Preparation Example 8 Formula

[0066]

Embedded image

[Wherein, Me, Ph, iBu and A are as defined above. Using a silicone polymer with the structure shown in
A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the formulations shown in Table I below were used. Table I shows the nonvolatile content and the acid value of the obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter, referred to as polymer A-VIII).

Preparation Example 9 Formula

[0069]

Embedded image

[Wherein, Me, Ph, iBu and A are as defined above. Using a silicone polymer with the structure shown in
A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the formulations shown in Table I below were used. Table I shows the nonvolatile content and the acid value of the obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter referred to as polymer A-IX).
Shown in

Preparation Example 10 Formula

[0072]

Embedded image

[Wherein, Me, Ph, iBu and A are as defined above. Using a silicone polymer with the structure shown in
A colorless and transparent varnish was obtained in the same manner as in Preparation Example 1 except that the formulations shown in Table I below were used. Table I shows the nonvolatile content and acid value of the obtained silicone polymer having a hydroxyl group and a carboxyl group (hereinafter, referred to as polymer AX).
Shown in

[0074]

[Table 1]

[0075]

Preparation Examples 11 to 14 Preparation examples 11 to 14 describe the preparation of a polymer having a carboxyl group and a carboxylic acid ester group used in the curable resin composition of the present invention.

Preparation Example 11 Preparation of acid anhydride group-containing polymer which is a precursor of a polymer having a carboxyl group and a carboxylic acid ester group 2 liters equipped with a thermometer, a stirrer, a cooling tube, a nitrogen inlet tube and a dropping funnel The reaction vessel was charged with 250 parts of xylene, and 500 parts of Solvesso-100 (manufactured by Esso), heated to 130 ° C., heated to 130 ° C., 215 parts of styrene, 225 parts of butyl acrylate, 115 parts of isobutyl methacrylate, and 160 parts of itaconic anhydride. , 250 parts of propylene glycol monomethyl ether acetate and t-butyl peroxy-2-ethylhexanoate 100
Parts of the monomer and the initiator solution were added dropwise over 3 hours, kept at 130 ° C. for 30 minutes, 15 parts of xylene and 15 parts of t-butylperoxy-2-ethylhexanoate were added dropwise over 30 minutes, and 1 part of Stirring was continued for an hour, and 900 parts of the solvent were removed under reduced pressure to obtain an acid anhydride group-containing acrylic polymer having a nonvolatile content of 77% and a number average molecular weight of 2,300.

Preparation Example 12 Preparation of polymer containing acid anhydride group which is a precursor of a polymer having a carboxyl group and a carboxylic acid ester group 215 parts of styrene, 85 parts of 2-ethylhexyl acrylate, 200 parts of isobutyl methacrylate and 200 parts of maleic anhydride An acid anhydride group-containing acrylic polymer having a nonvolatile content of 78% and a number average molecular weight of 2,000 was obtained in the same manner as in Preparation Example 11 except that a monomer composed of 215 parts of an acid was used.

Preparation Example 13 Preparation of Polymer Having Carboxyl Group and Carboxylic Ester Group The acid anhydride group-containing acrylic polymer 38 obtained in Preparation Example 11
45.0 parts of methanol was added to 5 parts and reacted at 65 ° C. for 24 hours to obtain a polymer having a carboxyl group and a carboxylic ester group (hereinafter, referred to as polymer BI). It was confirmed by IR that the absorption of the acid anhydride group (1785 cm ^-1 ) disappeared.

Preparation Example 14 Preparation of Polymer Having Carboxyl Group and Carboxylic Acid Ester Group The acrylic anhydride-containing acrylic polymer 38 obtained in Preparation Example 12
By adding 25.0 parts of methanol to 5 parts and reacting at 65 ° C. for 24 hours, a polymer having a carboxyl group and a carboxylic acid ester group (hereinafter, referred to as polymer B-II) was obtained. It was confirmed by IR that the absorption of the acid anhydride group (1785 cm ^-1 ) disappeared.

[0080]

Preparation Examples 15 and 16 Preparation Examples 15 and 16 describe the preparation of a polymer having a hydroxyl group and an epoxy group used in the curable resin composition of the present invention.

Preparation Example 15 A 2-liter reaction vessel equipped with a thermometer, stirrer, cooling tube, nitrogen inlet tube and dropping funnel was charged with 500 parts of butyl acetate, and the temperature was raised to 125 ° C.

In a dropping funnel, 50 parts of styrene, 400 parts of glycidyl methacrylate, 350 parts of 4-hydroxybutyl acrylate
, A monomer consisting of 200 parts of 2-ethylhexyl acrylate and 150 parts of t-butylperoxy-2-ethylhexanoate, and an initiator solution were added dropwise over 3 hours. After maintaining at 125 ° C. for 30 minutes after completion of the dropwise addition, a solution comprising 10 parts of t-butylperoxy 2-ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes. After completion of the dropwise addition, the reaction was further continued at 125 ° C. for 2 hours. The nonvolatile content was 62%, the number average molecular weight was 2500, the hydroxy equivalent was 436 (g solid) and the epoxy equivalent was 375 (g
A polymer having a hydroxyl group and an epoxy group (lid) was obtained (hereinafter referred to as polymer CI).

Preparation Example 16 250 parts of xylene and 500 parts of butyl acetate were charged into a 2 liter reaction vessel equipped with a thermometer, a stirrer, a cooling tube, a nitrogen inlet tube and a dropping funnel, and the temperature was raised to 125 ° C.

In a dropping funnel, 220 parts of styrene, 320 parts of glycidyl methacrylate, 4-hydroxybutyl acrylate 220
, A monomer consisting of 240 parts of 2-ethylhexyl methacrylate and 150 parts of t-butylperoxy-2-ethylhexanoate, and an initiator solution were added dropwise over 3 hours. After maintaining at 125 ° C. for 30 minutes after completion of the dropping, t-butylperoxy 2-
A solution consisting of 10 parts of ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes. 125 ° C for another 2 hours after dropping
The reaction is continued at 61%, nonvolatile content 61%, number average molecular weight 2500,
Hydroxy equivalent 683 (g solid) and epoxy equivalent 464 (g
A polymer having a hydroxyl group and an epoxy group (solid) (hereinafter, referred to as polymer C-II) was obtained.

[0085]

Examples 1 to 14 In Examples 1 to 14, paints containing the curable resin composition of the present invention obtained using the polymers prepared in Preparation Examples 1 to 16 will be described.

Example 1 First, a resin composition was prepared according to the formulation shown in the following table.

Ingredients Compounding (parts by weight) Polymer AI (Preparation Example 1) 100 Polymer BI (Preparation Example 13) 270 Polymer CI (Preparation Example 15) 295 Tinuvin-900 7 Sanol LS-292 4 Tetrabutylammonium bromide 3

Then, the obtained resin composition was mixed with a solvent consisting of ethoxyethyl propionate / xylene = 1/1 to prepare No.
4 Ford cup was diluted to a viscosity of 30 seconds / 20 ° C. Nippon Paint Co., Ltd.'s Super Rack M-
After applying 90 metallic bases, the above clear was applied by wet-on-wet and baked at 140 ° C. for 30 minutes. The paint and the coating film were evaluated by the following evaluation methods. The results are shown in Table III.

The non-volatile content of the paint was unified to No. 4 Ford cup (30 seconds / 20 ° C.) and measured.

Alkali Resistance After the obtained cured coating film was brought into contact with 0.2 ml of 0.1N NaOH aqueous solution at 50 ° C. for 2 hours, the coating film surface was visually evaluated.
When no change was observed, it was regarded as "no abnormality".

Acid Resistance The cured film thus obtained was brought into contact with 0.2 ml of a 10% aqueous solution of H ₂ SO ₄ at 50 ° C. for 2 hours, and the surface of the film was visually evaluated.
When no change was observed, it was regarded as "no abnormality".

2 × 2 cm flannel cloth coated with 1 g of a 50% aqueous dispersion of a scratch-resistant cleanser (commercially available as a new homing cleanser from Kao Corporation; 87% abrasive, 5% surfactant, and others) Was attached to a Gakushin-type dyed material friction fastness tester (manufactured by Daiei Kagaku Seiki Co., Ltd.). Then, the obtained cured coating film was loaded with a load of 500 g for 10
It rubbed back and forth. The percentage of 20 G before and after friction measured by using a gloss meter manufactured by Suga Test Instruments Co., Ltd. is indicated by%. The correspondence with the visual evaluation is shown below.

> 90: no change 80-90: faint but not noticeable 70-80: slightly visible 70>: clearly visible

X rubbing Xylene was immersed in octave-folded gauze, pressed against the coated surface, and reciprocated 10 times to observe the change in the coating film.

[0095] Except for using an formulations shown in Table II of Examples 2 to 11 below in the same manner as in Example 1, a clear coating compositions of Examples 2 to 11 were prepared and evaluated paint and film properties. Table III shows the evaluation results.

Examples 12 to 14 Examples 1 to 3 described in column 9, line 16 to column 10, line 6 of US Pat. No. 5,183,504 were prepared as base coating compositions. The phosphoric acid-treated steel sheet was middle-coated in the same manner as in Example 1 of the present invention, and then the above-mentioned base paint was spray-coated. 60
After preheating at 5 ° C. for 5 minutes, the clear paint of Example 1 was applied and cured at 140 ° C. for 30 minutes, and the same evaluation as in Example 1 was performed. The results are shown in Table III.

[0097] Except for using an formulations shown in Table II Comparative Example 1 and 2 below in the same manner as in Example 1, to prepare a clear coating material of Comparative Example 1 and 2,
Paint and coating performance were evaluated. Table III shows the evaluation results.

[0098]

[Table 2]

[0099]

[Table 3]

[0100]

[Table 4]

As shown by the results in Table III, Examples 1 to 11
Clear paint has a higher non-volatile content than the comparative example and provides a coating film having excellent acid resistance and scratch resistance.

[0102]

According to the present invention, there is provided a high solid content curable resin composition which provides a coating film having excellent weather resistance, especially resistance to acid rain, and excellent scratch resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08G 59/20 C08G 59/20 59/68 59/68 C09D 133/02 C09D 133/02 183/04 183/04 // B05D 7 / 14 B05D 7/14 L (72) Inventor Kazuhiko Takeoka 19-17 Ikedanakamachi, Neyagawa City, Osaka Japan Paint Co., Ltd. (72) Inventor Yoshitaka Okude 19-17 Ikedanakamachi, Neyagawa City, Osaka Japan Paint Stock In-company (72) Inventor Takeo Kurauchi 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (56) References JP-A-55-5977 (JP, A) JP-A-1-138228 (JP, A) JP-A-2-45577 (JP, A) JP-A-2-64181 (JP, A) JP-A-3-172318 (JP, A) JP-A-3-287650 (JP, A) JP-A-4- 136022 (JP, A) JP-A-4-325513 JP, A) (58) investigated the field (Int.Cl. ^6, DB name) C09D 163/00 - 163/10 C09D 183/04 - 183/06 C09D 133/02 C08G 59/20 C08G 59/68 B05D 1 / 36 B05D 7/24 B05D 7/14

Claims (7)

(57) [Claims] (1) Formula (a) (i) Wherein R ¹ is a methyl, phenyl or phenylethyl group, and R ² and R ³ are independently methyl, phenyl,
Phenylethyl, 3-hydroxypropyl or 3- (hydroxyethoxy) propyl, R ⁴ is methyl, 3-hydroxypropyl or 3- (hydroxyethoxy) propyl, and R ⁵ is methyl, phenyl, phenylethyl or An isobutyl group, l is an integer of 1 to 20, m
Is an integer of 2 to 4, and n is an integer of 0 to 2. A hydroxyl group-containing silicone polymer having an average of 3 to 12 hydroxyl groups in one molecule, which is at least one selected from the group consisting of compounds having the structure represented by the formula: and (ii) an acid anhydride group-containing compound. , The hydroxyl group and the acid anhydride group are 1 / 1.0 to 1 / 0.2
(B) (i) (1) an acid anhydride group-containing ethylenically unsaturated monomer obtained by performing a half-esterification reaction at an amount of: Fifteen
To 40% by weight and (2) 60 to 85% by weight of another copolymerizable ethylenically unsaturated monomer to obtain (ii) a polymer having 1 to 12 carbon atoms. Having a carboxyl group and a carboxylate group, which are obtained by reacting a hydroxyl group-containing compound containing atoms with an acid anhydride group and a hydroxyl group in a molar ratio of 1 / 1.5 to 1/1 in a molar ratio. 20 to 60% by weight of polymer; and (c) (i) formula Wherein R is a hydrogen atom or a methyl group, and m is 2-8
N is an integer of 3 to 7, and q is an integer of 0 to 4. 5 to 40% by weight of a hydroxyalkyl (meth) acrylate having a structure represented by the formula: (ii) 10 to 60% by weight of an epoxy group-containing ethylenically unsaturated monomer, and (iii) optionally other copolymerizable ethylene. Curable resin composition comprising 30 to 60% by weight of a polymer containing a hydroxyl group and an epoxy group, which is obtained by copolymerizing 0 to 85% by weight of an unsaturated monomer. 2. The curable resin composition according to claim 1, further comprising a quaternary ammonium salt catalyst. 3. The curable resin composition according to claim 1, which contains an organotin compound. 4. A coating composition comprising the curable resin composition according to claim 1, 2 or 3 as a binder component. (A) a step of forming an undercoat and, if necessary, an intermediate coat on the substrate; (B) a step of applying a water-based or solvent-based base paint on the formed coat; (C) Without curing the applied base paint, the (a) (i) formula Wherein R ¹ is a methyl, phenyl or phenylethyl group, and R ² and R ³ are independently methyl, phenyl,
Phenylethyl, 3-hydroxypropyl or 3- (hydroxyethoxy) propyl, R ⁴ is methyl, 3-hydroxypropyl or 3- (hydroxyethoxy) propyl, and R ⁵ is methyl, phenyl, phenylethyl or An isobutyl group, l is an integer of 1 to 20, m
Is an integer of 2 to 4, and n is an integer of 0 to 2. A hydroxyl group-containing silicone polymer having an average of 3 to 12 hydroxyl groups in one molecule, which is at least one selected from the group consisting of compounds having the structure represented by the formula: and (ii) an acid anhydride group-containing compound. , The hydroxyl group and the acid anhydride group are 1 / 1.0 to 1 / 0.2
(B) (i) (1) an acid anhydride group-containing ethylenically unsaturated monomer obtained by performing a half-esterification reaction at a ratio of: An acid anhydride group-containing polymer obtained by copolymerizing 15 to 40% by weight of (2) 60 to 85% by weight of another copolymerizable ethylenically unsaturated monomer is used as (ii) 1 to 12 A hydroxyl group-containing compound containing a carbon atom, and an acid anhydride group and a hydroxyl group are present in a molar ratio of 1 / 1.5 to 1/1.
A polymer having a carboxyl group and a carboxylic acid ester group, which is obtained by reacting in an amount of
20-60% by weight; and formula (c) (i) Wherein R is a hydrogen atom or a methyl group, and m is 2-8
N is an integer of 3 to 7, and q is an integer of 0 to 4. 5 to 40% by weight of a hydroxyalkyl (meth) acrylate having a structure represented by the formula: (ii) 10 to 60% by weight of an epoxy group-containing ethylenically unsaturated monomer, and (iii) optionally other copolymerizable ethylene. Paint containing 30 to 60% by weight of a polymer containing a hydroxyl group and an epoxy group, obtained by copolymerizing 0 to 85% by weight of an unsaturated monomer, as a binder component A coating film forming method, comprising: applying the composition; and (D) curing the applied base paint and clear paint by heating. 6. The method according to claim 5, wherein the curable resin composition contains a quaternary ammonium salt catalyst. 7. The method according to claim 5, wherein the curable resin composition contains an organotin compound.