JP2003002926A - Antifoaming agent for water paint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive imparting a defoaming property to water paint and an excellent finished appearance by adding to the aqueous paint, suppressing coating defects such as repelling and crater forming due to foams, and contributing to the improvement of the appearance. SOLUTION: The additive is a polymer obtained by introducing trimethylsilyl group in an amount of >=2 wt.%, preferably >=5 wt.% into a copolymer which is conventionally used as an antifoaming agent for an aqueous paint, and has a number-average molecular weight of 1,000-100,000. When added in a small amount, the additive exhibits the excellent defoaming property in the water paint by suppressing the occurrence of coating defects such as reppelling and crater forming, and resultingly it can give excellent finishing to the paint.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel defoaming agent for water-based paint, which is added to the water-based paint in a small amount to impart defoaming properties to bubbles generated during the production of the water-based paint or during coating. It is related to agents.

[0002]

2. Description of the Related Art In recent years, attempts have been made to use water-based paints instead of solvent-based paints in order to save resources and prevent environmental pollution. For example, its use is being considered for intermediate coatings for automobiles, base coatings, and top coatings. Along with this, there has been a demand for higher-performance antifoaming agents for water-based paints. For this purpose, conventionally, isoparaffinic compounds such as mineral oil, organic polymers such as vinyl polymers and polyether polymers, and modified silicone oils dispersed in a surfactant have been mainly used. .

[0003]

However, according to the conventional techniques, in the fields requiring high appearance such as automobile applications which have been studied in recent years, sufficient defoaming property and coating such as armpits generated at the time of baking are applied. It is difficult to say that improvement of defects can be obtained, and when many additives are added in order to obtain a good appearance, coating defects such as cissing are caused, and adverse effects such as separation of the additive itself from the paint are often observed.

Therefore, an object of the present invention is to provide an antifoaming agent which can be used in applications requiring a high appearance, which has not been obtained by conventional defoaming agents for water-based paints.

[0005]

Means for Solving the Problems As a result of various studies, the present inventors have found that when the antifoaming agent for water-based paints described in (1) to (4) below was added to water-based paints, good results not hitherto obtained. It was discovered that defoaming properties are imparted and that coating defects such as cracks that occur during baking can be prevented. (1) Reactive monomer (A) having a trimethylsilyl group represented by the structural formula —Si (CH ₃ ) ₃ in the molecular structure and / or tris represented by the structural formula —Si [OSi (CH ₃ ) ₃ ] ₃ A reactive monomer (B) having a trimethylsilyl group in the molecular structure in the form of a (trimethylsiloxy) silyl group and a general formula H ₂ C═CH—O—R ₁ [wherein R ₁ has ₁ to 10 carbon atoms]. Represents 12 alkyl groups. ] The vinyl ether monomer (C) represented by

[0006]

[Chemical 4]

[In the formula, R ₂ and R ₃ each represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ] Acrylamide (D) and / or general formula

[0008]

[Chemical 5]

[Wherein R ₄ is a hydrogen atom or a methyl group, and R _{5 is}
Represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, m represents an integer of 1 to 100, and n represents an integer of 2 to 4, respectively. ] (Meth) acrylic ester (E) and / or general formula

[0010]

[Chemical 6]

(Wherein R ₆ represents a hydrogen atom or a methyl group) and a (meth) acrylic acid (F) represented by a copolymer obtained by copolymerization with the copolymer. , 2% by weight or more, preferably 5% by weight or more, of a trimethylsilyl group derived from (A) and / or (B), and 2% by weight or more, preferably 5% by weight or more, of a copolymerized unit derived from (C) And / or (D) and / or (E)
And / or (F) -containing copolymerized units in an amount of 5% by weight or more, preferably 10% by weight or more, and having a number average molecular weight of 1,000 to 100,000, preferably 2,000 to 20,000. Defoamer for water-based paints. (2) A polyfunctional monomer capable of introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group, and the vinyl ether monomer (C) according to claim 1.
And acrylamide (D) and / or (meth) acrylic acid ester (E) and / or (meth) according to claim 1.
It comprises a copolymer obtained by reacting a copolymer of acrylic acid (F) with a compound having a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group, and the copolymer has a trimethylsilyl group of 2 % Or more, preferably 5% by weight or more, and 2% by weight or more, preferably 5% by weight or more, of a copolymer unit derived from (C),
And containing 5% by weight or more, preferably 10% by weight or more, of copolymerized units derived from (D) and / or (E) and / or (F), and a number average of 1000 to 100000, preferably 2000 to 20000. An antifoaming agent for water-based paints, which has a molecular weight. (3) The monomer (A) and / or (B) according to claim 1, the vinyl ether monomer (C) according to claim 1, and the acrylamide (D) and / or (meth) according to claim 1. It comprises a copolymer obtained by copolymerizing an acrylic ester (E) and / or (meth) acrylic acid (F) with a monomer (G) copolymerizable therewith, and the copolymer is , Trimethylsilyl group 2
More than 5% by weight, preferably more than 5% by weight, and
Containing 2% by weight or more, preferably 5% by weight or more, of the copolymerized units derived from (C), and 5% by weight of the copolymerized units derived from (D) and / or (E) and / or (F). The above content is preferably 10% by weight or more, and the copolymerization unit derived from (G) is contained in a range not exceeding 50% by weight, and 1000 to 100000, preferably 200.
An antifoaming agent for water-based paints, which has a number average molecular weight of 0 to 20,000. (4) A polyfunctional monomer capable of introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group, and the vinyl ether monomer (C) according to claim 1.
And acrylamide (D) and / or (meth) acrylic acid ester (E) and / or (meth) according to claim 1.
From a copolymer obtained by reacting a copolymer of acrylic acid (F) and a monomer (G) copolymerizable therewith with a compound having a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group The copolymer contains 2% by weight or more, preferably 5% by weight or more of trimethylsilyl groups, and 2% by weight or more, preferably 5% by weight or more of copolymerized units derived from (C), and ,
Containing 5% by weight or more, preferably 10% by weight or more, of the copolymerized units derived from (D) and / or (E) and / or (F), and 50 units of the copolymerized units derived from the monomer (G).
It is contained in the range of not more than wt% and 1000 to 1
A defoaming agent for water-based paints, which has a number average molecular weight of preferably 2,000 to 20,000.

The above defoaming agent for water-based paints of the present invention needs to have a trimethylsilyl group content of 2% by weight or more, and if it is less than this, a sufficient effect as an antifoaming agent for water-based paints is obtained. unacceptable.

The reason why the vinyl ether monomer represented by the general formula (C) is copolymerized is to obtain an effect of obtaining a good defoaming property, and a monomer having a structure other than this does not give a sufficient defoaming property. Can not.

The acrylamides of the general formula (D) and / or the polyalkylene glycol ester of the general formula (E) and / or the (meth) acrylic acid of the general formula (F) are copolymerized to obtain the desired polymer. This is to impart hydrophilicity to the resin so that it can be uniformly dispersed in the water-based paint. When each of the monomers of the general formulas (D) and (E) and (F) is used, their proportions are arbitrary, so that the amount of trimethylsilyl groups in the copolymer is 2% by weight or more. Blended such that the content of the copolymerized units derived from the monomer (C) is 2% by weight or more, and the copolymer derived from each of the monomers (D) and (E) and (F). It may be used so that the total content of the polymerized units is 5% by weight or more.

A polyfunctional monomer capable of introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group, a monomer (C), a monomer (D) and / or (E) and / or (F) are preliminarily used. After polymerization, it is also possible to introduce a silane compound containing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group by an addition reaction or a condensation reaction. Also in this case, the proportion of the trimethylsilyl group introduced into the polymer is 2% by weight or more, the copolymerized units derived from the monomer (C) are contained in 2% by weight or more, and the monomer (D) and / or If the copolymerized units derived from (E) and / or (F) are contained in an amount of 5% by weight or more, the effect of similarly imparting good defoaming property is recognized.

The proportion of trimethylsilyl groups in the synthesized polymer is 2% by weight or more, the copolymerized units derived from the monomer (C) are contained in 2% by weight or more, and the monomers (D) and / Or (E) and / or (F)
If the copolymerized unit derived from is contained in an amount of 5% by weight or more,
The copolymer obtained by copolymerizing the other reactive monomer (G) within the range where the proportion of the copolymerized units in the polymer does not exceed 50% by weight similarly imparts good defoaming property. The effect is recognized.

Polyfunctional monomer capable of introducing trimethylsilyl group, monomer (C), monomer (D) and / or (E) and / or (F) and other reactive monomer (G)
If the acrylic silicon polymer obtained by previously copolymerizing and with a silane compound containing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group by an addition reaction or a condensation reaction also satisfies the following conditions, The effect of imparting a good defoaming property is recognized. That is, the proportion of the trimethylsilyl group introduced into the polymer containing the polyfunctional monomer is 2% by weight or more, and
Containing 2% by weight or more of copolymerized units derived from the monomer (C), and 5% by weight or more of copolymerized units derived from the monomer (D) and / or (E) and / or (F). If so, even if the other reactive monomer (G) is copolymerized within the range where the proportion of the copolymerized units in the polymer does not exceed 50% by weight, the same effect of imparting good defoaming property can be obtained. Is recognized.

The number average molecular weight of the synthesized copolymer is 100.
When it is less than 0, the copolymer compounded in the coating composition does not have sufficient ability to exert the defoaming effect in the coating composition, so that sufficient defoaming property cannot be obtained. Further, when the number average molecular weight of the synthesized copolymer is larger than 100,000, the copolymer cannot be uniformly dispersed in the water-based paint and the possibility of coating defects such as cissing increases.

Examples of the reactive monomer having a trimethylsilyl group (A) and the reactive monomer having a trimethylsilyl group in the form of a tris (trimethylsiloxy) silyl group (B) include 3-methacryloxypropyltrimethylsilane and 3 -Methacryloxypropyl tris (trimethylsiloxy) silane, vinyl tris (trimethylsiloxy) silane and the like can be mentioned.

Examples of silane compounds having a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group include trimethylchlorosilane, hexamethyldisilazane, tris (trimethylsiloxy) hydrosilane, and 3
-Aminopropyltris (trimethylsiloxy) silane, 3-mercaptopropyltris (trimethylsiloxy) silane and the like can be mentioned.

The carbon number of R _{1 represented by} the general formula (C) is 1
Examples of vinyl ethers Nos. 12 to 12 include ethyl vinyl ether, normal propyl vinyl ether, isopropyl vinyl ether, normal butyl vinyl ether, isobutyl vinyl ether, tertiary butyl vinyl ether, normal octyl vinyl ether, 2-ethylhexyl vinyl ether, and methyl vinyl ether.

Examples of the acrylamides represented by the general formula (D) include acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N-isopropyl acrylamide, N-normal butyl acrylamide,
Examples include N-tert-butyl acrylamide, N-ethylhexyl acrylamide, N, N-dimethyl acrylamide, N, N-diethyl acrylamide, diacetone acrylamide, and the like.

As the (meth) acrylic acid ester represented by the general formula (E), for example, (meth) acrylic acid 2-
Methoxyethyl ester, (meth) acrylic acid 2-ethoxyethyl ester, (meth) acrylic acid 2-butoxyethyl ester, (meth) acrylic acid 2-octoxyethyl ester, (meth) acrylic acid 2-lauroxyethyl ester, (Meth) acrylic acid 2-stearoxyethyl ester, (meth) acrylic acid 3-methoxybutyl ester, (meth) acrylic acid 4-methoxybutyl ester, (meth) acrylic acid ethylcarbitol ester,
(Meth) acrylic acid methoxy polyethylene glycol (ethylene glycol polymerization number 2 to 100) ester, (meth) acrylic acid methoxy polypropylene glycol (propylene glycol polymerization number 2 to 100) ester, (meth) acrylic acid methoxy poly ester (Ethylene-propylene) glycol (Ethylene glycol-
Propylene glycol having a polymerization number of 2 to 100) ester, (meth) acrylic acid methoxypoly (ethylene-tetramethylene) glycol (ethylene glycol-tetramethylene glycol having a polymerization number of 2 to 100) ester, (meth) acrylic acid butoxypoly (Ethylene-propylene) glycol (ethylene glycol-propylene glycol having a polymerization number of 2 to 100) ester,
Octoxy poly (ethylene-propylene) glycol (meth) acrylate (ethylene glycol-propylene glycol having a polymerization number of 2 to 100) ester, lamethoxy (meth) acrylate polyethylene glycol (ethylene glycol having a polymerization number of 2 to 100) Esters and the like can be mentioned.

Examples of polyfunctional monomers capable of introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group are, for example, (meth) acrylic acid,
(Meth) acrylic acid 2-hydroxyethyl ester,
(Meth) acrylic acid glycidyl ester, (meth) acrylic acid 2-isocyanate ethyl ester, general formula (E) wherein R ₅ is a hydrogen atom, allyl glycidyl ether, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, etc. Can be mentioned.

The monomer (G) is not limited, and examples thereof include (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid normal propyl ester, (meth) acrylic acid isopropyl ester, and the like. (Meth) acrylic acid normal butyl ester, (meth) acrylic acid isobutyl ester, (meth) acrylic acid tertiary butyl ester, (meth)
Acrylic acid normal octyl ester, (meth) acrylic acid 2-ethylhexyl ester, (meth) acrylic acid isononyl ester, (meth) acrylic acid lauryl ester, (meth) acrylic acid tridecyl ester, (meth) acrylic acid myristyl ester, (Meth) acrylic acid hexadecyl ester, (meth) acrylic acid stearyl ester, (meth) acrylic acid behenyl ester,
(Meth) acrylic acid cyclohexyl ester, (meth)
(Meth) acrylic acid esters such as acrylic acid isobornyl ester and (meth) acrylic acid nonylphenoxy polyethylene glycol ester; vinyl ethers other than the above such as hexadecyl vinyl ether, octadecyl vinyl ether; styrene, α-methylstyrene, chlorostyrene , Vinyltoluene and other aromatic hydrocarbon vinyl compounds; vinyl acetate, vinyl propionate, diallyl phthalate and other vinyl esters and allyl compounds;
Other vinyl compounds such as vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, and fluoroolefin maleimide may be mentioned.

As the method for synthesizing the copolymer used in the present invention, there are an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method and the like, and as an initiator for carrying out the polymerization, it is generally used. An azo polymerization initiator or a peroxide is used.

As a method for introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group into a polymer, a reaction containing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group after a polymerization reaction is performed. There is a method of adding or condensing the silane.

Since the present invention relates to the function of the copolymer, it is not limited by the method of synthesizing the copolymer.

The paint suitable for the defoaming agent for water-based paint obtained in the present invention is a paint which is required to have a high appearance. For example, it imparts sufficient defoaming properties at the time of coating water-based base coatings for automobiles, water-based intermediate coatings for automobiles, water-based primer coatings for automobiles, water-based coatings for high-end furniture, and at the same time prevents the occurrence of coating defects such as armpits.

The antifoaming agent for water-based paint according to the present invention may be added to the paint at any time, and may be added in the process of kneading the pigment or after the paint is manufactured.

The addition amount of the antifoaming agent for water-based paint according to the present invention varies depending on the kind of resin of the paint and the compounding composition of the pigment, but is usually 0.01 in terms of solid content relative to the paint vehicle.
To 5% by weight, preferably 0.05 to 2% by weight.

If the amount added is less than 0.01% by weight, sufficient defoaming properties cannot be imparted. Further, if it is added in an amount of more than 5% by weight, there is a large possibility that various adverse effects will occur during recoating, which is not preferable.

[0033]

The antifoaming agent for water-based paints of the present invention is a novel copolymer and is capable of providing unprecedented good defoaming properties.

[0034]

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

"Parts" and "%" in the following mean "parts by weight" and "% by weight", respectively.

Production Example 1 Propylpropylene glycol (hereinafter abbreviated as PFG) was placed in a 1000 ml reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen gas inlet.
After charging 150 parts and raising the temperature to 110 ° C. while introducing nitrogen gas, the dropping solution (a-1) shown below was dropped at a constant rate in 2 hours with a dropping funnel.

Dropping solution (a-1) Tertiary butyl vinyl ether 120 parts N-isopropylacrylamide 120 parts Acrylic acid 60 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 100 parts PFG 100 parts t-butylperoxy-2- 5 parts of ethyl hexanoate 1 hour after the completion of the dropwise addition of the solution (a-1), 2 parts of t-butylperoxy-2-ethylhexanoate was added, and the mixture was further reacted for 2 hours while maintaining 110 ° C. . After the reaction was completed, the reaction solution was adjusted to a concentration of 50% with PFG to obtain an additive [A-1]. The polystyrene-converted number average molecular weight of the synthesized copolymer by gel permeation chromatography was 15,000.

Production Example 2 Additives [A] were prepared in the same manner as in Example 1 except that the following dropping solution (a-2) was used in place of the dropping solution (a-1) of Production Example 1. -2] was obtained.

Dropping solution (a-2) isobutyl vinyl ether 150 parts N, N-dimethylacrylamide 225 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 125 parts PFG 150 parts t-butylperoxy-2-ethylhexanoate The polystyrene-converted number average molecular weight by gel permeation chromatography of 10 parts of the synthesized copolymer was 9000.
Met.

Production Example 3 Additive [A] was prepared in the same manner as in Example 1 except that the following dropping solution (a-3) was used in place of the dropping solution (a-1) of Production Example 1. -3] was obtained.

Dropping solution (a-3) Tertiary butyl vinyl ether 100 parts Acrylic acid 2-methoxyethyl ester 100 parts 3-Methacryloxypropyltris (trimethylsiloxy) silane 100 parts Acrylic acid 2-ethylhexyl ester 100 parts PFG 50 parts t -Butylperoxy-2-ethylhexanoate 10 parts The vinylsilicone-based copolymer synthesized had a number average molecular weight in terms of polystyrene of 5000 by gel permeation chromatography.

Production Example 4 The same as Example 1 except that the following dropping solution (a-4) was used in place of the dropping solution (a-1) of Production Example 1 and the reaction temperature was changed to 80 ° C. The additive [A-4] was obtained by the method of.

Dropping solution (a-4) isobutyl vinyl ether 150 parts N, N-dimethylacrylamide 150 parts acrylic acid 100 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 100 parts PFG 50 parts 2,2'-azobis (4 -Methoxy-2,4-dimethylvaleronitrile) 2 parts The number average molecular weight in terms of polystyrene by gel permeation chromatography of the synthesized copolymer is 2000
It was 0.

Manufacturing Example 5 Additives [A] were prepared in the same manner as in Example 1 except that the following dropping solution (a-5) was used instead of the dropping solution (a-1) of Manufacturing Example 1. -5] was obtained.

Dropping solution (a-5) Tertiary butyl vinyl ether 60 parts Acrylic acid lauropolyethylene glycol ester (ethylene glycol addition mole number 10) 60 parts Acrylic acid 60 parts 3-methacryloxypropyltrimethylsilane 120 parts PFG 150 parts t -Butylperoxy-2-ethylhexanoate 25 parts The polystyrene-converted number average molecular weight by gel permeation chromatography of the synthesized copolymer was 2000.
Met.

Production Example 6 Additives [A] were prepared in the same manner as in Example 1 except that the following dropping solution (a-6) was used in place of the dropping solution (a-1) of Production Example 1. -6] was obtained.

Dropping solution (a-6) Tertiary butyl vinyl ether 240 parts N, N-dimethylacrylamide 240 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 20 parts PFG 50 parts t-butylperoxy-2-ethylhexa The number average molecular weight in terms of polystyrene by gel permeation chromatograph of the copolymer synthesized with 25 parts of Noate was 8,000.
Met.

Production Example 7 After reacting in the same manner as in Example 1 except that the following dropping solution (a-7a) was used in place of the dropping solution (a-1) of Production Example 1, ( a-7b) and then the additive [A-
7] was obtained.

Dropping solution (a-7a) Tertiary butyl vinyl ether 150 parts N, N-dimethylacrylamide 150 parts Acrylic acid 50 parts Methacrylic acid 2-isocyanate ethyl ester 50 parts PFG 50 parts t-Butylperoxy-2-ethylhexa Noate 10 parts dropping solution (a-7b) 3-aminopropyltris (trimethylsiloxy) silane 150 parts 1 hour after completion of dropping solution (a-7a), t-butylperoxy-2-ethylhexanoate 3 Parts were added, and the reaction was continued for 2 hours while maintaining 110 ° C. After completion of the reaction, the mixture was cooled to room temperature and the dropping solution (a-7b) was added dropwise over 1 hour. After standing for 24 hours, the nonvolatile content was adjusted to 50% with PFG to obtain an additive [A-7].

The polystyrene-converted number average molecular weight of the synthesized copolymer by gel permeation chromatography was 10,000.

Production Example 8 After reacting in the same manner as in Example 1 except that the following dropping solution (a-8a) was used instead of the dropping solution (a-1) of Production Example 1, ( a-8b) and then the additive [A-
8] was obtained.

Dropping solution (a-8a) Tertiary butyl vinyl ether 150 parts N-tert-butyl acrylamide 50 parts Methacrylic acid 2-isocyanate ethyl ester 50 parts Acrylic acid 50 parts Acrylic acid isobornyl ester 100 parts PFG 50 parts t-butyl Peroxy-2-ethylhexanoate 12.5 parts dropping solution (a-8b) 3-aminopropyltris (trimethylsiloxy) silane 150 parts 1 hour after the end of dropping solution (a-8a), t-butylper Oxy-2-ethylhexanoate (3 parts) was added, and the mixture was further reacted for 2 hours while maintaining 110 ° C. After completion of the reaction, the mixture was cooled to room temperature and the dropping solution (a-8b) was added dropwise over 1 hour. After standing for 24 hours, the non-volatile content was adjusted to 50% with PFG to obtain an additive [A-8].

The polystyrene-converted number average molecular weight of the synthesized copolymer by gel permeation chromatography was 9000.

Production Comparative Example 1 Additives [N] were prepared in the same manner as in Example 1 except that the following dropping solution (n-1) was used in place of the dropping solution (a-1) of Production Example 1. -1] was obtained.

Dropping Solution (n-1) Isobutyl Acrylate 200 parts Acrylic Acid 50 parts 3-Methacryloxypropyltris (trimethylsiloxy) silane 100 parts PFG 150 parts t-Butylperoxy-2-ethylhexanoate 7. The polystyrene-converted number average molecular weight by gel permeation chromatography of 5 parts of the synthesized copolymer was 6000.
Met.

Production Comparative Example 2 Additives [N] were prepared in the same manner as in Example 1 except that the following dropping solution (n-2) was used in place of the dropping solution (a-1) of Production Example 1. -2] was obtained.

Dropping solution (n-2) Methacrylic acid methoxypolyethylene glycol ester (ethylene glycol polymerization number 23) 200 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 100 parts PFG 100 parts t-butylperoxy- 2-Ethylhexanoate 6 parts The polystyrene-converted number average molecular weight by gel permeation chromatography of the synthesized copolymer is 1100.
It was 0.

Production Comparative Example 3 Additives [N] were prepared in the same manner as in Example 1 except that the following dropping solution (n-3) was used in place of the dropping solution (a-1) of Production Example 1. -3] was obtained.

Dropping solution (n-3) Tertiary butyl vinyl ether 200 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 200 parts Acrylic acid ethyl ester 100 parts PFG 100 parts t-butylperoxy-2-ethylhexanoate The polystyrene-converted number average molecular weight by gel permeation chromatography of 10 parts of the synthesized copolymer was 8000.
Met.

Production Comparative Example 4 Additives [N] were prepared in the same manner as in Example 1 except that the following dropping solution (n-4) was used in place of the dropping solution (a-1) of Production Example 1. -4] was obtained.

Dropping solution (n-4) Tertiary butyl vinyl ether 240 parts N, N-dimethylacrylamide 250 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 10 parts PFG 150 parts t-butylperoxy-2-ethylhexa The number average molecular weight in terms of polystyrene by gel permeation chromatograph of the copolymer of 5 parts of Noeight was 1000.
It was 0.

Production Comparative Example 5 Same as Example 1 except that the following dropping solution (n-5) was used in place of the dropping solution (a-1) of Production Example 1 and the reaction temperature was changed to 80 ° C. The additive [N-5] was obtained by the method described in 1.

Dropping solution (n-5) isobutyl vinyl ether 150 parts N, N-dimethylacrylamide 150 parts acrylic acid 100 parts 3-methacryloxypropyltris (trimethylsiloxy) silane 100 parts 2,2'-azobis (4-methoxy-) 2,4-dimethylvaleronitrile) 0.5 part The polystyrene-converted number average molecular weight of the synthesized copolymer by gel permeation chromatography is 1100.
It was 00.

Production Comparative Example 6 Additives [N] were prepared in the same manner as in Example 1 except that the following dropping solution (n-6) was used in place of the dropping solution (a-1) of Production Example 1. -6] was obtained.

Dropping Solution (n-6) Tertiary Butyl Vinyl Ether 50 Parts N-Tertiary Butyl Acrylamide 50 Parts Acrylic Acid 50 Parts 3-Methacryloxypropyltris (trimethylsiloxy) silane 50 Parts PFG 350 Parts t-Butyl Peroxy- 40 parts of 2-ethylhexanoate The polystyrene-converted number average molecular weight of the copolymer synthesized by gel permeation chromatography was 800.

Production Comparative Example 7 AQ-500 was used as a commercially available polymer-based defoaming agent.
(Kusumoto Kasei Co., Ltd.) was used. This is an additive [N
-7].

Production Comparative Example 8 AQ-5 was used as a commercially available silicone antifoaming agent.
56 (manufactured by Kusumoto Kasei Co., Ltd.) was used. This was used as an additive [N-8].

[0068]

[Table 1]

[0069]

[Table 2]

Paint Test Example 1 (Defoaming Test on Aqueous Base Paint) The defoaming test was performed on the aqueous base paint compositions having the formulations shown in Tables 3 and 4. (Preparation of Metallic Base Paint) Acrylic melamine-based water-based metallic base paints were prepared by mixing uniformly in the order of formulation A to formulation C in Table 3 with a lab disper. The resulting paint was treated with dimethylethanolamine to P
After adjusting the H to be 7.8, the viscosity was diluted with distilled water so that the viscosity was 30 seconds (20 ° C.) with Ford cup # 4. (Test for defoaming property in cans) First for adjusted water-based base paint
The amount of active ingredient in the paints in Tables and 2 is 0.2
% To add 4000% with a lab disper
The mixture was stirred at m for 3 minutes and foamed.

One minute after the completion of stirring, the specific gravity of the aqueous base coating material containing bubbles was measured using a 100 ml specific gravity cup (manufactured by Taiyu Kikai Co., Ltd.). It can be said that the greater the specific gravity, the higher the effect of breaking up the bubbles that have been caught. (Preparation of Intermediate Coating Plate) The viscosity of the intermediate coating composition shown in Table 5 was adjusted to 18 seconds with a Ford cup # 4 using a diluting solvent, and then a tin plate (0.3 mm × 200 mm) was used.
mm × 300 mm) with air spray coating and 140 ° C for 20
Bake in the oven for a minute. Three coated sheets were prepared for each test sample.

(Test of defoaming property at the time of coating) The prepared metallic base paint was left for 24 hours and then coated on two intermediate coating plates by air spray so that the film thickness after drying would be 15 μm. After drying for 10 minutes in an oven at 80 ° C, one coated plate was baked for 20 minutes in an oven at 140 ° C. After cooling the other coated plate to room temperature, apply the top clear paint shown in Table 4 by air spray to a dry film thickness of 40μ, set for 10 minutes, and then in an oven at 140 ° C. Bake for 20 minutes.

On the third intermediate coating plate, a metallic base coating was applied by gradient spraying with an air spray so that the film thickness after drying was from 15 μ to 75 μ. 1 in an oven at 80 ° C
After drying for 0 minutes, it was cooled to room temperature, and then the top clear paint of Table 4 was applied by air spray to a dry film thickness of 40 μm. After setting for 10 minutes, it was baked in an oven at 140 ° C. for 20 minutes.

(Evaluation of defoaming property at the time of coating) The defoaming property was evaluated by defoaming property of the water-based base coating itself and generation of armpits after applying the top clear coat and wet cissing caused by the entrapped foam. Occurrence of each occurrence is visually "best"
The evaluation was made in 5 grades from (5) to "worst" (1). The results are shown in Table 6.

[0075]

[Table 3]

[0076]

[Table 4]

[0077]

[Table 5]

[0078]

[Table 6]

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 290/06 C08F 290/06 // C09D 5/00 C09D 5/00 Z 7/12 7/12 201 / 00 201/00 F-term (reference) 4J027 AC02 AC03 AC04 AC06 BA06 BA07 BA10 BA14 CB04 CD08 4J038 CG001 CJ241 CL002 DA161 DL082 GA02 GA08 KA07 MA08 MA14 NA23 PB07 4J100 AE02S AE03S AE04R09BA01P15BA01P15AQR15A08AQR15A08QR15A08QAQR15A08QAQR15A08QAQR15A08QAQR15A08QAQR8AQAQR8AQAQR8APRQAM08RAL08QAL08R08AM07RAL08QAL08R08AM07RAL08QAL08R08AM07RAL08QAL08R08AM08RAL08QAL08AR08AM08RAL08QAL08R08AM07RAL08QAL08R08AM07RAL08QAL02 JA15

Claims (4)

[Claims] 1. A reactive monomer (A) having a trimethylsilyl group represented by the structural formula —Si (CH ₃ ) ₃ in the molecular structure and / or a structural formula —Si [OSi (CH ₃ ) ₃ ] ₃ And a reactive monomer (B) having a trimethylsilyl group in the molecular structure in the form of a tris (trimethylsiloxy) silyl group, and a general formula H ₂ C═CH—O—R ₁ [wherein R ₁ is the number of carbon atoms. It represents an alkyl group of 1 to 12. ] And a vinyl ether monomer (C) represented by the general formula: [In the formula, R ₂ and R ₃ each represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. ] And / or the general formula: [In the formula, R ₄ represents a hydrogen atom or a methyl group, R ₅ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, m represents an integer of 1 to 100, and n represents an integer of 2 to 4, respectively. ] (Meth) acrylic acid ester (E) and / or the general formula [Wherein, R ₆ represents a hydrogen atom or a methyl group] and a (meth) acrylic acid (F) represented by a copolymer obtained by copolymerizing the copolymer,
It contains 2% by weight or more of a trimethylsilyl group derived from (A) and / or (B), and 2% by weight or more of a copolymerized unit derived from (C), and (D) and / or ( An antifoaming agent for water-based paints, which comprises 5% by weight or more of copolymerized units derived from E) and / or (F) and has a number average molecular weight of 1,000 to 100,000. 2. A polyfunctional monomer capable of introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group, the vinyl ether monomer (C) according to claim 1, and the acrylamide (D) according to claim 1. ) And / or (meth) acrylic acid ester (E) and / or (meth) acrylic acid (F), and a compound having a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group The copolymer thus obtained, which contains 2% by weight or more of trimethylsilyl groups and 2% by weight or more of copolymerized units derived from (C), and (D) and Containing 5% by weight or more of copolymerized units derived from / or (E) and / or (F),
An antifoaming agent for water-based paints, which has a number average molecular weight of 1,000 to 100,000. 3. The monomer (A) according to claim 1 and / or
Or (B), the vinyl ether monomer (C) according to claim 1, and the acrylamide (D) and / or (meth) acrylic acid ester (E) and / or (meth) acrylic acid (according to claim 1). F) and a monomer (G) copolymerizable therewith, which is a copolymer obtained by copolymerizing the monomer (G) with a trimethylsilyl group of 2
At least 2% by weight, and at least 2% by weight of copolymerized units derived from (C), and (D) and / or (E)
And / or 5% by weight or more of the copolymerized units derived from (F), and 50% by weight or less of the copolymerized units derived from (G), and 1000 to 100000 An antifoaming agent for water-based paints having a number average molecular weight of 1. 4. A polyfunctional monomer capable of introducing a trimethylsilyl group and / or a tris (trimethylsiloxy) silyl group, the vinyl ether monomer (C) according to claim 1, and the acrylamide (D) according to claim 1. ) And / or (meth) acrylic acid ester (E) and / or (meth) acrylic acid (F), and a copolymerizable monomer (G) with these, a trimethylsilyl group and / or tris It is composed of a copolymer obtained by reacting a compound having a (trimethylsiloxy) silyl group, and the copolymer contains 2% by weight or more of a trimethylsilyl group and contains 2 (C) -derived copolymerized units. A copolymer containing 5% by weight or more of copolymerized units derived from (D) and / or (E) and / or (F) and containing monomer (G). An antifoaming agent for water-based paints, which contains a polymerized unit in a range not exceeding 50% by weight and has a number average molecular weight of 1,000 to 100,000.