JP3108516B2 - Thermosetting topcoat composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting composition, and more specifically, for example, to a building exterior, an automobile, an industrial machine,
The present invention relates to a thermosetting topcoat composition suitable for use as a topcoat for steel furniture, home appliances, and plastics members.

[0002]

2. Description of the Related Art
As thermosetting paints, alkyd melamine resin paints, acrylic melamine resin paints, epoxy melamine resin paints and the like are known. Since these paints use volatile melamine as a crosslinking agent for the polyol, odor caused by by-products generated has been regarded as a problem.

Further, the above-mentioned conventional paints using melamine as a cross-linking agent are not yet sufficient in terms of water repellency (contact angle of water) retention and weather resistance. From the viewpoint of resource saving and energy saving, there has been a demand for the development of a high-performance paint excellent in maintenance-free water repellency retention and weather resistance from the viewpoint of resource saving and energy saving.

[0004] In order to solve these problems, a polyol and a melamine are crosslinked in a completely different manner from the conventional crosslinking method using a polyol and a melamine to give a cured coating film having excellent weather resistance, chemical resistance, solvent resistance and the like. A paint comprising a mixture of a hydrolyzable silyl group-containing polymer has been proposed (see Japanese Patent Application Laid-Open No. 1-11952).

However, there is a problem that the coating material comprising this mixture generally has a poor balance between the physical properties of water repellency retention and recoat adhesion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a topcoat paint which can provide a cured coating film having a good balance of physical properties of water repellency retention and recoat adhesion. The purpose of the present invention is to provide a thermosetting topcoat composition suitable for use as

[0007]

Thermosetting top coating composition according to the present invention for achieving the above objects resolving means for the] includes acrylic resin (A) having a hydroxyl group, alkoxysilyl represented by the following general formula of 9 Group-containing acrylic copolymer (B) and powder
An organopolysiloxane (C) having a reactive functional group at the end and / or the side chain, and an acrylic resin having the hydroxyl group
Fat (A) and the alkoxysilyl group-containing acrylic copolymer
0.18 based on 100 parts by weight of the total solid content of the combined (B)
And 50 parts by weight, singly or in mixture of two or more silane compounds represented by the following general formula of 10 was obtained by partial hydrolysis, the organopolysiloxane (C) and the
A partially condensed condensate (D) having a hydrolyzable methoxysilyl group and having a number average molecular weight of 250 to 2,500, and / or an alcohol (E) having a boiling point of 120 ° C. or more. And consisting of

[0008]

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[However, in the chemical formula 9 , R ¹ has 1 to 10 carbon atoms.
R ² is a hydrogen atom or a group having 1 to 1 carbon atoms
1 selected from the group consisting of an alkyl group having 0, an aryl group having 1 to 10 carbon atoms, and an aralkyl group having 1 to 10 carbon atoms.
A is 0, 1 or 2; ]

[0010]

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[0011] [However, in reduction 10, R ¹ is 1 to 3 carbon atoms
0 alkyl group, an aryl group having 1 to 30 carbon atoms, an aralkyl group having 1 to 30 carbon atoms or of 11, of 12, of
A monovalent group represented by the following formula ( 13) , (14) , (15) or (16) , and n is an integer of 0 to 3. ]

[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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The acrylic resin (A) having a hydroxyl group in the present invention is used to cause the cured product immediately after baking to exhibit various physical properties such as hardness and solvent resistance. Since the main chain is substantially composed of an acrylic copolymer, the cured product is excellent in weather resistance, chemical resistance, water resistance and the like.

The acrylic resin (A) having a hydroxyl group can be obtained, for example, by mixing a hydroxyl-containing vinyl polymerizable compound with acrylic acid,
It is obtained by copolymerizing methacrylic acid or a derivative thereof.

The hydroxyl group-containing vinyl polymerizable compound in this case includes, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate (hereinafter, acrylate and methacrylate are collectively referred to as “(meth) acrylate”), Propyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, Alonix 5700, 4-hydroxystyrene manufactured by Toa Gosei Chemical Industry Co., Ltd., HE-10 manufactured by Nippon Shokubai Chemical Industry Co., Ltd. , HE-20, HP-
10 and HP-20 (all of which are acrylate oligomers having a hydroxyl group at the terminal), Blemmer-PP series (polypropylene glycol methacrylate), Blemmer-PE series (polyethylene glycol monomethacrylate), Blemmer-PE
P series (polyethylene glycol polypropylene glycol methacrylate), Bremma-AP-400
(Polypropylene glycol monoacrylate), Blemmer-AE-350 (polyethylene glycol monoacrylate), Blemmer-NKH-5050 (polypropylene glycol polytrimethylene monoacrylate) and Blemmer-GLM (glycerol monomethacrylate), a hydroxyl-containing vinyl compound and ε -Caprolactone-modified hydroxyalkylvinyl-based monomers obtained by reaction with caprolactone. Among them, ε-caprolactone-modified hydroxyalkylvinyl-based monomers are preferable because they can impart more excellent impact resistance and flexibility to the coating film.

A typical example of the ε-caprolactone-modified hydroxyalkylvinyl monomer is a vinyl monomer represented by the following general formula (17).

[0022]

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Wherein R is a hydrogen atom or a methyl group;
n is an integer of 1 or more. Commercially available vinyl monomers represented by Chemical Formula 17 include Daicel's Placel
l FA-1 (R = H, n = 1), Placel
FA-4 (R = H, n = 4), Placel FM
-1 (R = CH ₃ , n = 1), the same Placel FM
-4 (R = CH ₃ , n = 4), TONE manufactured by UCC
M-100 (R = H, n = 2) and TONE M-
201 (R = CH ₃ , n = 1). One of these hydroxyl-containing vinyl polymerizable compounds may be used alone, or two or more of them may be used in combination as needed.

The derivative of acrylic acid or methacrylic acid copolymerizable with the hydroxyl group-containing vinyl polymerizable compound is not particularly limited, and specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, and n-butyl ( Meth) acrylate, isobutyl (meth) acrylate,
2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (Meth) acrylonitrile, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth)
Acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth)
Acrylamide, N, N-dimethyl (meth) acrylamide, N-methylacrylamide, acryloylmorpholine, N-methylol (meth) acrylamide, AS-6, AN, a macromonomer manufactured by Toa Gosei Chemical Industry Co., Ltd.
-6, AA-6, AB-6, AK-5, hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyalkyl esters of (meth) acrylic acid and phosphoric acid or phosphoric acid esters And a (meth) acrylate containing a urethane bond or a siloxane bond, which is a phosphoric ester group-containing vinyl compound which is a condensation product of the above.

The acrylic resin (A) having a hydroxyl group is 5
Within a range not exceeding 0% by weight (hereinafter abbreviated as "%"), the main chain may contain a portion formed by a urethane bond or a siloxane bond, and may be derived from a monomer other than the (meth) acrylic acid derivative. May be included.

The above-mentioned monomers are not limited, and specific examples thereof include aromatic hydrocarbon-based vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and vinyltoluene; maleic acid, fumaric acid, Unsaturated carboxylic acids such as itaconic acid, salts thereof (alkali metal salts, ammonium salts, amine salts, etc.), their acid anhydrides (maleic anhydride, etc.) Unsaturated carboxylic esters such as diesters and half esters with branched alcohols; vinyl esters and allyl compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl compounds containing amino groups such as vinyl pyridine and aminoethyl vinyl ether; Acid diamide, crotonamide, maleic diamide, Mar diamide, N- vinyl pyrrolidone amide group-containing vinyl compound such as pyrrolidone; methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide,
Other vinyl compounds such as N-vinylimidazole and vinylsulfonic acid are exemplified.

As a method for synthesizing the acrylic resin (A) having a hydroxyl group, a peroxide radical initiator such as t-butyl peroxyacetate or an azo radical initiator such as azobisisobutyronitrile is used. The legal method is preferred in that the synthesis is easy.

In the solution polymerization method, n-
Dodecyl mercaptan, t-dodecyl mercaptan, n
The molecular weight may be adjusted using a chain transfer agent such as -butyl mercaptan. The solvent used for the solution polymerization is not particularly limited as long as it is a solvent that is non-reactive with the raw material monomers and the like.

Further, an acrylic resin having a hydroxyl group (A)
May be a non-aqueous dispersion type in which polymer particles insoluble in a non-polar organic solvent such as heptane and pentane are dispersed.

The molecular weight of the acrylic resin (A) having a hydroxyl group is not particularly limited, but the physical properties of the cured coating film such as durability formed from the curable composition according to the present invention (hereinafter referred to as “coating film physical properties”). ), The number average molecular weight is 1,50
0-40,000 is preferable, and 3,000-2
More preferably, it is 5,000. Further, the acrylic resin (A) having a hydroxyl group must have a sufficient number of crosslinkable hydroxyl groups, and a resin having a hydroxyl value of 10 to 300 mgKOH / g in terms of strength and durability. It is more preferably 30 to 150 mgKOH / g. Acrylic resin having hydroxyl group (A)
May be used alone or, if necessary, in combination of two or more.

The alkoxysilyl group-containing acrylic copolymer (B) in the present invention has at least one, preferably two or more, alkoxysilyl groups represented by the following general formula (18) in one molecule. If the average number of alkoxysilyl groups in one molecule is less than 1, the solvent resistance of the resulting coating film will be poor.

[0032]

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However, in the chemical formula 18, R ¹ has 1 to 1 carbon atoms.
0, preferably 1 to 4 alkyl groups, R ² is a hydrogen atom,
Or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an aryl group having 1 to 10 carbon atoms, and an aralkyl group having 1 to 10 carbon atoms, a Is 0, 1 or 2.

An alkoxysilyl group represented by the following formula:
The alkoxysilyl group-containing acrylic copolymer (B) may be contained at the terminal of the main chain, may be contained in the side chain, or may be contained in both the terminal and the side chain of the main chain. Good.

[0035] When the number of carbon atoms of R ¹ exceeds 10, reduces the hydrolysis of alkoxysilyl group, group R ¹ is other than alkyl group, such as phenyl group, even a benzyl group, hydrolysis resistance Decrease.

Specific examples of R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,
Isobutyl groups. Specific examples of the alkyl group for R ² include the same alkyl groups as those described in the description of R ¹ , specific examples of the aryl group include a phenyl group, and specific examples of the aralkyl group Is a benzyl group.

Specific examples of the alkoxysilyl group represented by Chemical Formula 18 include an alkoxysilyl group contained in an alkoxysilyl group-containing monomer described below.

Since the alkoxysilyl group-containing acrylic copolymer (B) has a main chain substantially composed of an acrylic copolymer, the cured product obtained is excellent in weather resistance, chemical resistance, water resistance and the like. Becomes Further, since the alkoxysilyl group is directly bonded to the carbon atom, the cured product has excellent water resistance, alkali resistance, acid resistance and the like.

The number average molecular weight of the alkoxysilyl group-containing acrylic copolymer (B) is from 1,000 to more in view of the physical properties of the coating film obtained from the thermosetting top coating composition according to the present invention.
The range of 30,000 is preferable, and 3,000-25.0.
A range of 00 is more preferred.

The alkoxysilyl group-containing acrylic copolymer (B) can be obtained by, for example, copolymerizing acrylic acid, methacrylic acid, a derivative thereof, etc. with an alkoxysilyl group-containing monomer.

The derivative of acrylic acid or methacrylic acid is not particularly limited, and specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth).
Acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile, glycidyl (Meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-
Butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N-methylol (meth) acrylamide, Toa Gosei Alonix M-5700 manufactured by Chemical Industry Co., Ltd., AS-6, AN-, a macromonomer manufactured by Toa Gosei Chemical Industry Co., Ltd.
6, AA-6, AB-6, AK-5, Daicel P
lacel FA-1, Placel FA-4,
Placel FM-1, Placel FM-
4. Phosphate ester group-containing vinyl, which is a condensation product of hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyalkyl esters of (meth) acrylic acid and phosphoric acid or phosphoric acid esters. And a (meth) acrylate containing a urethane bond or a siloxane bond.

The alkoxysilyl group-containing monomer is not particularly limited, except that it has a polymerizable double bond, and specific examples thereof include compounds represented by the following chemical formulas (19) to (30). Other examples include (meth) acrylates having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond.

[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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The proportion of the portion formed by the alkoxysilyl group-containing monomer in the alkoxysilyl group-containing acrylic copolymer (B) is preferably in the range of 5 to 90% from the viewpoint of the curability of the composition and the physical properties of the coating film. And the range of 11 to 70% is more preferable.

The alkoxysilyl group-containing acrylic copolymer (B) may contain a portion formed by a urethane bond or a siloxane bond in the main chain within a range not exceeding 50%. It may contain a portion derived from a monomer other than the acid derivative.

The monomers other than the above (meth) acrylic acid derivatives are not particularly limited, and specific examples thereof include aromatic monomers such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene. Hydrocarbon-based vinyl compounds; unsaturated carboxylic acids such as maleic acid, fumaric acid and itaconic acid, salts thereof (alkali metal salts, ammonium salts, amine salts, etc.), acid anhydrides thereof (maleic anhydride, etc.), or Unsaturated carboxylic acid esters such as diesters and half esters thereof with linear or branched alcohols having 1 to 20 carbon atoms; vinyl esters such as vinyl acetate, vinyl propionate and diallyl phthalate; allyl compounds; vinyl pyridine, amino Amino group-containing vinyl compounds such as ethyl vinyl ether Itaconic acid diamide, crotonamide, diamide of maleic acid, fumaric acid diamide, amide group-containing vinyl compounds such as N- vinyl pyrrolidone; 2-
Hydroxyethyl vinyl ether, methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene,
Other vinyl compounds such as isoprene, fluoroolefin maleimide, N-vinylimidazole, vinylsulfonic acid and the like can be mentioned.

The alkoxysilyl group-containing acrylic copolymer (B) can be produced by a method disclosed in, for example, JP-A-54-36395, JP-A-57-36109, and JP-A-58-157810. You can,
From the viewpoint of easiness of synthesis, etc., it is most preferable to produce the compound by a solution polymerization method using an azo radical initiator such as azobisisobutyronitrile.

At the time of this solution polymerization, n-
Dodecyl mercaptan, t-dodecyl mercaptan, n
-Butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane,
The molecular weight can be adjusted by using a chain transfer agent such as a compound represented by the following formula (31). Further, by using a chain transfer agent having an alkoxysilyl group in the molecule, for example, γ-mercaptopropyltrimethoxysilane, and by continuously replenishing the amount consumed during the progress of the reaction, in addition to controlling the molecular weight, This is preferable because an alkoxysilyl group can be introduced into the terminal of the silyl group-containing acrylic copolymer.

[0060]

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Examples of the polymerization solvent in the case of the above solution polymerization method include hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), and ethers (ethylene glycol monoethyl). Ether, ethylene glycol mono-n-
Any solvent that is non-reactive with the raw material monomer, such as butyl ether, ethylene glycol monoethyl ether acetate), ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, methyl isobutyl ketone, acetone, etc.) can be used without particular limitation. .
The alkoxysilyl group-containing acrylic copolymer (B) in the present invention may be used singly or may be used depending on the application.
More than one species may be used in combination.

The mixing ratio of the acrylic resin (A) having a hydroxyl group and the acrylic copolymer (B) having an alkoxysilyl group in the present invention is not particularly limited.
The (A) / (B) component ratio is preferably in the range of 9/1 to 1/9 by weight, more preferably in the range of 8/2 to 2/8.
If the component ratio (A) / (B) exceeds 9/1, the water resistance of the coating film obtained from the composition of the present invention tends to decrease, and
If it is less than / 9, the effect of blending the acrylic resin (A) having a hydroxyl group tends to be insufficient.

The organopolysiloxane (C) in the present invention imparts water repellency to the coating film, maintains water cissing (for example, water cissing after a weather resistance test), and
A component used to prevent the attachment of contaminants such as dust and the like. It has a reactive functional group at the terminal and / or side chain and has a hydroxyl group-containing resin (A) and an alkoxysilyl group-containing polymer (B). ) Can be used without any particular limitation as long as they are compatible with ()).

The organopolysiloxane (C) has a linear,
It may have any of a branched, reticulated or cyclic structure, and the organo group (organic group) includes a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a methyl group, an ethyl group, a propyl group, and a butyl group. Group, hexyl group, allyl group,
And a phenyl group. Among them, organo groups such as methyl group, vinyl group and phenyl group, which are industrially manufactured and are inexpensive, are practically advantageous. As the reactive functional group, a silanol group, an alkoxysilyl group,
Examples include an alcoholic hydroxyl group, a glycidyl group, an amino group, a mercapto group, a carboxyl group, an amide group, a vinyl group, and a (meth) acryloxy group. Among them, a silanol group, an alkoxysilyl group, and an alcoholic hydroxyl group represented by the following formula (32) are preferable. The number of reactive functional groups is preferably one or more in one molecule of the organopolysiloxane (C).

[0065]

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The molecular weight of the organopolysiloxane (C) can be appropriately selected within a range compatible with the acrylic resin (A) having a hydroxyl group and the acrylic copolymer having an alkoxysilyl group, but as the molecular weight increases, the molecular weight increases. Since the compatibility is reduced, the silicon atom is
Those containing 00 are preferable, those having 2 to 100 are more preferable, and those having 3 to 50 are particularly preferable.

The following are specific examples of the organopolysiloxane (C). That is, those having an alkoxysilyl group as a reactive functional group are represented by the following formulas 33, 34, 35 or 36, and those having a silanol group as a reactive functional group are , 38, 39 or 40 having other reactive functional groups include:
Of 41, of 42, those represented by the formula 43 or of 44, are respectively illustrated.

[0068]

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In the formula, R is a phenyl group and has 1 to 1 carbon atoms.
4, a monovalent group selected from the group consisting of an alkyl group and a hydroxyl group, l, m, and n are each an integer of 1 to 5. ]

[0070]

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[In the formula, n is an integer of 2 to 20]

[0072]

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In the formula, m and n are each an integer of 1 to 10. ]

[0074]

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Wherein R is an alkyl group having 1 to 5 carbon atoms, and n is an integer of 2 to 10. ]

[0076]

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[0077]

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[0078]

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[0079]

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[Wherein Me is a methyl group, P
h is a phenyl group, R is a phenyl group, an alkyl group having 1 to 4 carbon atoms or a hydroxyl group, and m and n are integers of 1 to 50. ]

[0081]

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[0082]

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[0083]

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[0084]

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In the formulas (41) to (44), X is an organic functional group selected from the following formulas (45) to (54), R is a methyl group, a phenyl group or a C ₆ H ₅ CH ₂ CH ₂ — group, n and m is 1
Is an integer of ５０50. ]

[0086]

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[0087]

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[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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Wherein R and R ^′ are alkyl groups having 1 to 5 carbon atoms. ]

[0097]

[0098]

[0099]

[0100]

[0101]

The above organopolysiloxane (C) comprises 1
A single species may be used, or two or more species may be used as needed. The compounding amount of the organopolysiloxane (C)
The total solid content of the acrylic resin (A) having a hydroxyl group and the acrylic copolymer (B) having an alkoxysilyl group is 100.
0.1 parts by weight (hereinafter abbreviated as “parts”)
8 to 50 parts . If the amount is too small, it is difficult to sufficiently exhibit water repellency and the like. If the amount is too large, problems occur in compatibility, repelling , and the like.

The partially hydrolyzed condensate (D) in the present invention
Specific examples of methyl silicate, methyltrimethoxysilane, ethyltrimethoxysilane, butyltrimethoxysilane, octyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltri Methoxysilane, γ-acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane,
γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-propyltrimethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dibutyldimethoxysilane, diphenyldimethoxysilane, vinylmethyldimethoxysilane, γ-methacryloxypropylmethyldimethoxy Examples thereof include partially hydrolyzed condensates of silane compounds such as silane, trimethylmethoxysilane, triethylmethoxysilane, and triphenylmethoxysilane, which have an average molecular weight of 250 to 2,500.

The partially hydrolyzed condensate (D) is prepared by adding a required amount of water to one or a mixture of two or more of the above silane compounds, and further adding a small amount of hydrochloric acid, sulfuric acid or the like as a condensation catalyst if necessary. At a temperature of normal temperature to 100 ° C. while removing the produced methanol to promote the condensation.

Commercially available products obtained by partially hydrolyzing and condensing methyl silicate and having a methoxysilyl group include methyl silicate 47, methyl silicate 51, methyl silicate 55, methyl silicate 55 and methyl silicate 55 of Nippon Corkate Co., Ltd. Silicate 58, methyl silicate 6
And a partially hydrolyzed condensate having a methoxysilyl group obtained by partially hydrolyzing and condensing methyltrimethoxysilane, dimethyldimethoxysilane, and the like. , AFP
-2, AFP-6, KR213, KR217, KR92
18; TRS165, TR335 of Toshiba Silicone Co., Ltd.
7; Y-1567, FZ-3701 of Nippon Unicar Co., Ltd.
FZ-3704 and the like.

The amount of the above-mentioned partially hydrolyzed condensate (D) is 1% of the total solid content of the hydroxyl-containing acrylic resin (A) and the alkoxysilyl group-containing acrylic copolymer (B).
The amount is usually 0.01 to 100 parts, preferably 0.5 to 20 parts with respect to 00 parts.

Specific examples of the alcohol (E) having a boiling point of 120 ° C. or higher in the present invention include n-amyl alcohol, isoamyl alcohol, 3-methoxybutyl alcohol, n-hexyl alcohol, 2-methylpentanol, and secondary hexyl. Alcohol, 2-ethylbutyl alcohol, secondary heptyl alcohol, heptanol, n-octyl alcohol, 2-ethylhexyl alcohol, secondary octyl alcohol, nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, n-dodecanol , Secondary undecyl alcohol, trimethyl nonyl alcohol, secondary tetradecyl alcohol, phenol, cyclohexanol, methyl cyclohexanol,
Examples include 3,3,5-trimethylcyclohexanol, benzyl alcohol, and diacetone alcohol.

If the boiling point of the alcohol (E) is lower than 120 ° C., the alcohol volatilizes during spray coating or during setting before heat curing, so that a sufficient effect cannot be obtained. Alcohol (E) has a high boiling point and remains in the coating film until the end of curing. It is thought that this changes the surface properties of the final coating film and improves the balance between hardness and impact resistance and the adhesion between layers in two coats and two bake.

The mixing amount of the alcohol (E) is in the range of 3 to 100 parts with respect to 100 parts of the total resin solid content of the acrylic resin (A) having a hydroxyl group and the acrylic copolymer (B) having an alkoxysilyl group. Preferably, the range of 5 to 70 parts is more preferable. If the blending amount of the alcohol (E) is less than 3 parts, the impact resistance and interlayer adhesion become insufficient, and if it exceeds 100 parts, the viscosity is lowered and the workability is lowered, which is not preferable.

Alcohol (E) is an acrylic resin (A)
And alkoxysilyl group-containing acrylic copolymer (B)
May be blended with one or both of the above at any time before, during, or after the polymerization, and a blend of an acrylic resin having a hydroxyl group (A) and an alkoxysilyl group-containing acrylic copolymer (B) When alcohol (E) is used as a polymerization solvent for acrylic resin (A) and alkoxysilyl group-containing acrylic copolymer (B), compatibility between alcohol and resin is sufficient, and the effect is stable. I do.

In order to shorten the curing time, a curing catalyst may be added to the thermosetting top coating composition of the present invention.
Specific examples of the curing catalyst in that case include dibutyltin laurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, a polymer of dioctyltin maleate, and an organic tin compound such as tin octylate; phosphoric acid, monomethyl Phosphate or phosphate such as phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide , Glycidyl methacrylate, glycidol, acrylic glycidyl ether, γ-glycidoxypropyltrimethoxysilane, γ- Glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, a compound represented by the following formula, and epoxy compounds such as Cardura E manufactured by Yuka Shell Epoxy, Epicoat 828, Epicoat 1001, and phosphorus Addition reaction product with an acid and / or monoacid phosphate; organic titanate compound; organic aluminum compound such as aluminum tris (ethylacetoacetate) and aluminum tris (acetylacetonate); tetrabutyl zirconate, tetrakis (acetylacetonate) ) Organic zirconium compounds such as zirconium, tetraisobutyl zirconate, butoxytris (acetylacetonate) zirconium; maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, Click acid, phthalic acid, trimellitic acid, pyromellitic acid, acid anhydrides thereof, acidic compounds such as p-toluenesulfonic acid; hexylamine, di-2-ethylhexylamine, N, N-
Amines such as dimethyldodecylamine and dodecylamine; mixtures or reactants of these amines with acidic phosphate esters; and alkaline compounds such as sodium hydroxide and potassium hydroxide.

[0112]

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Among the curing catalysts exemplified above, organotin compounds, acidic phosphates, mixtures or reactants of acidic phosphates and amines, saturated or unsaturated polycarboxylic acids or acid anhydrides, Silicon compound,
An organic titanate compound, an organic aluminum compound, an organic zirconium compound or a mixture of two or more thereof is preferred because of its high activity. The curing catalyst in the present invention is 1
A single species may be used, or two or more species may be used as needed.

Although the amount of the curing catalyst is not particularly limited, it is usually 0.1 parts by weight based on 100 parts of the total resin solid content of the hydroxyl group-containing acrylic resin (A) and the alkoxysilyl group-containing acrylic copolymer (B). The range is preferably from 20 to 20 parts, more preferably from 0.1 to 10 parts. If the amount of the curing catalyst is less than 0.1 part, the curability tends to decrease, and if it exceeds 20 parts, the appearance of the coating film tends to deteriorate, which is not preferable.

The thermosetting composition according to the present invention is usually used after blending a solvent. The solvent in this case can be blended without particular limitation as long as it is a non-reactive solvent. Specific examples include aliphatic hydrocarbons and halogenated hydrocarbons used in general paints and coating agents. Hydrogens, alkyl alcohols, ketones, esters,
Examples include ethers, alcohol esters, ketone alcohols, ether alcohols, ketone ethers, ketone esters, ester ethers, and the like. Among them, alkyl alcohols are preferred in that the storage stability of the composition is improved.

The alkyl alcohols are preferably those having an alkyl group having 1 to 10 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, s-butyl alcohol. alcohol,
Examples include t-butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol, and ethylene glycol monoether. In the present invention, one kind of the solvent may be used alone, or two or more kinds may be used in combination as needed.

The amount of the alcohol as a solvent is not particularly limited, but may be 10 parts with respect to 100 parts of the total resin solid content of the acrylic resin (A) having a hydroxyl group and the acrylic copolymer (B) having an alkoxysilyl group. Or less, more preferably 50 parts or less. In general, the amount of the solvent varies depending on the molecular weight of the acrylic resin (A) having a hydroxyl group and the acrylic copolymer (B) containing an alkoxysilyl group and the composition of both, and may vary depending on the solid concentration and viscosity required for practical use. Adjusted accordingly. The alcohol (E) having a boiling point of 120 ° C. or higher also functions as a solvent, but the amount of the alcohol having a boiling point of 120 ° C. or higher is limited to the range described above. preferable.

In order to ensure storage stability that does not cause a problem with repeated use over a long period of time, it is preferable to add a dehydrating agent to the thermosetting composition according to the present invention. Specific examples of the dehydrating agent in that case include, for example, methyl orthoformate, ethyl orthoformate, methyl orthoacetate,
Examples include hydrolyzable ester compounds such as ethyl orthoacetate, methyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, methylsilicate, and ethylsilicate.

The dehydrating agent may be added before the polymerization of the alkoxysilyl group-containing acrylic copolymer (B), may be added after the polymerization, or may be added during the polymerization.

The amount of the dehydrating agent added is not particularly limited, but the total amount of the resin solids of the acrylic resin (A) having a hydroxyl group and the acrylic copolymer (B) having an alkoxysilyl group (B) is 10%.
Usually, 100 parts or less is preferable, and 50 parts or less is more preferable with respect to 0 parts.

By using the above-mentioned alkyl alcohol and a dehydrating agent together, the storage stability can be remarkably improved.

The thermosetting topcoat composition according to the present invention comprises:
Depending on the application, additives such as diluents, pigments such as extender pigments, ultraviolet absorbers, light stabilizers, anti-settling agents, leveling agents;
Cellulose such as nitrocellulose and cellulose acetate butyrate; resins such as epoxy resin, melamine resin, vinyl chloride resin, chlorinated polypropylene, chlorinated rubber and polyvinyl butyral; and fillers may be added.

After the thermosetting topcoat composition of the present invention is applied to an object by various coating methods, for example, dipping, spraying, brushing and the like, the temperature is usually 30 ° C. or higher, preferably 55 to 55 ° C. By curing at 350 ° C., a cured coating film having excellent adhesion, durability and the like can be formed on the surface of the object to be coated.

[0124]

EXAMPLES 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, and the present invention may be practiced by appropriately changing the gist of the invention. Is possible.

Synthesis Example 1 Synthesis of Acrylic Resin (A-1) Having Hydroxyl Group 31.3 butyl acetate was placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel.
And 9.5 parts of xylene, the temperature was raised to 110 ° C. while introducing nitrogen gas through a nitrogen gas inlet tube, and then a mixture having the following composition was dropped at a constant rate over 5 hours from a dropping funnel. did. 18.0 parts of styrene 28.3 parts methyl methacrylate 7.4 parts 32.5 parts of acrylic acid n- butyl xylene Placcel FM-1 31.8 parts of 2,2 ^'- azobisisobutyronitrile 1.8 parts of mixture after completion of the dropwise addition, 2,2 ^'- 0.2 parts of azobisisobutyronitrile was added dropwise over 1 hour 3.8 parts of toluene. Next, the reaction was allowed to proceed at 110 ° C. for 2 hours and cooled.
Xylene was added to the resin solution to adjust the solid content concentration to 60% to obtain an acrylic resin (A-1) having a hydroxyl group. The hydroxyl value (mgKOH / g soli) of this acrylic resin
d) was 72, and the number average molecular weight was 10,000. The above-mentioned Placel FM-1 is a reaction product of 2-hydroxyethyl methacrylate: ε-caprolactone 1: 1 manufactured by Daicel Corporation.

[0126]

[0127]

[ Synthesis Example 2 ] Synthesis of alkoxysilyl group-containing acrylic copolymer (B-1) Into the same reaction vessel as in Synthesis Example 1, 45.9 parts of xylene was charged, and 110 ° C was introduced while introducing nitrogen gas. After the temperature was raised to C, a mixture having the following composition was dropped at a constant speed from the dropping funnel over 5 hours. Styrene 12.8 parts Methyl methacrylate 50.1 parts Stearyl methacrylate 6.9 parts γ-methacryloxypropyltrimethoxysilane 30.2 parts Xylene 13.5 parts 2,2′-azobisisobutyronitrile 4.5 After completion of dropping of the mixture, 0.5 part of 2,2'-azobisisobutyronitrile and 5 parts of toluene were dropped at a constant speed over 1 hour. Then, after aging at 110 ° C for 2 hours, it was cooled,
Xylene was added to the resin solution to adjust the solid concentration to 60%, and the alkoxysilyl group-containing acrylic copolymer (B-
1) was obtained. The number average molecular weight of this alkoxysilyl group-containing acrylic copolymer (B-1) was 6,000.

[ Synthesis Example 3 ] Synthesis of alkoxysilyl group-containing acrylic copolymer (B-2) In a reaction vessel similar to that of Synthesis Example 1, 30.0 parts of 2-ethylhexyl alcohol and 15.9 parts of xylene were charged. After the temperature was raised to 110 ° C. while introducing nitrogen gas, a mixture having the following composition was dropped at a constant speed from the dropping funnel over 5 hours. Styrene 12.8 parts Methyl methacrylate 50.1 parts Stearyl methacrylate 6.9 parts γ-methacryloxypropyltrimethoxysilane 30.2 parts Xylene 13.5 parts 2,2′-azobisisobutyronitrile 4.5 After completion of dropping of the mixture, 0.5 part of 2,2'-azobisisobutyronitrile and 5 parts of toluene were dropped at a constant speed over 1 hour. Then, after aging at 110 ° C for 2 hours, it was cooled,
Xylene was added to the resin solution to adjust the solid concentration to 60%, and the alkoxysilyl group-containing acrylic copolymer (B-
2) was obtained. The number average molecular weight of this alkoxysilyl group-containing acrylic copolymer (B-2) was 6,300.

[0130]

Table 1 shows the raw material compositions used in Synthesis Examples 1 to 3 .

[0132]

[Table 1]

Examples 1-4 and Comparative Examples 1-2 Each component shown in Table 2 or Table 3 was mixed to prepare a topcoat clear coating. A coated steel sheet coated with an epoxy amide-based cationic electrodeposition primer and an intermediate coating surfacer was used as a test piece on a mild steel sheet subjected to degreasing and phosphate conversion treatment, and a commercially available acrylic melamine resin paint (silver metallic base) was applied thereon. Thereafter, tinuvin 900 (a benzotriazole-based ultraviolet absorber manufactured by Ciba-Geigy) and tinuvin 292 (a hindered amine-based light stabilizer manufactured by Ciba-Geigy) were added to each of the above top coat clear paints by a wet-on-wet method. Add 1 part each to 100 parts, dilute with xylene to a sprayable viscosity, and add 3 parts at 140 ° C.
Bake for 0 minutes. At this time, the dry film thickness of the base coat was about 15 μm, and the dry film thickness of the top coat clear paint was about 30 μm. Tables 2 and 3 show the results of evaluating the properties of each of the obtained coated articles by the following methods. Table 3 also shows, as a comparative example 3 , the characteristics of a coated product obtained by coating only a commercially available acrylic melamine paint for comparison.

(Contact Angle) Using a FACE contact angle meter CA-P type (manufactured by Kyowa Interface Science Co., Ltd.), the contact angle of each coated article with water after the initial and weather resistance tests was measured.
The weather resistance test was carried out using a Ubcon manufactured by Atlas Co., Ltd., with an ultraviolet irradiation time of 8 hours and a water coagulation (dark) of 4 hours as one cycle, for a total of 1,400 hours of acceleration test.

(Recoat adhesion) After applying an acrylic melamine resin paint (silver metallic base) to each of the above-mentioned painted products, a wet-on-wet method was used.
The above top coat clear paint was applied and baked at 140 ° C. for 30 minutes. After baking, the JIS
The test was performed by a grid test method based on K5400. 2
5/25 was evaluated as 10 points, and 0/25 was evaluated as 0 point.

[0136]

[Table 2]

[0137]

[Table 3]

From Tables 2 and 3, it can be seen that the thermosetting topcoat composition of the present invention has a small reduction in the contact angle even after the weather resistance test and is excellent in recoat adhesion.
Also, the ratio of Example 1 shown in Table 2 to Comparative Example 1 shown in Table 3
From the comparison, it was found that component (D) was added to the coating composition.
Balance between recoating and water repellency
It can be seen that is improved.

[0139]

According to the present invention, the thermosetting top coating composition according to the present invention has excellent unique effects such as excellent balance of physical properties such as water repellency retention and recoat adhesion.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisao Furukawa 4-5-7 Chikushigaoka, Kita-ku, Kobe City, Hyogo Prefecture (56) References JP-A-3-47871 (JP, A) JP-A-3-47854 (JP) JP-A-2-289642 (JP, A) JP-A-5-140477 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 133/04 C09D 133/14 C09D 183/04

Claims (4)

(57) [Claims] An acrylic resin having a hydroxyl group (A), an alkoxysilyl group-containing acrylic copolymer represented by the following general formula (B), and a terminal and / or side chain reactive
The water organopolysiloxane (C) having a functional group
Acrylic resin (A) having an acid group and the alkoxy resin
Total amount of solid content of the acrylic group-containing acrylic copolymer (B) 100
The organopoly obtained by partially hydrolyzing 0.18 to 50 parts by weight to one part by weight of a single silane compound represented by the following general formula 2 or a mixture of two or more thereof.
A condensate different from siloxane (C), having a hydrolyzable methoxysilyl group, and having a number average molecular weight of 250 to
A partially hydrolyzed condensate (D) of 2,500 and / or an alcohol (E) having a boiling point of 120 ° C. or higher. Embedded image Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms, an aryl group having 1 to 10 carbon atoms, and 1 to 1 carbon atoms.
A is a monovalent hydrocarbon group selected from the group consisting of 0 aralkyl groups, and a is 0, 1 or 2. [Chemical formula 2] Wherein R ¹ represents an alkyl group having 1 to 30 carbon atoms, an aryl group having 1 to 30 carbon atoms, an aralkyl group having 1 to 30 carbon atoms, or a compound represented by the following formulas: , Chemical 7
Or, a monovalent group represented by Chemical formula 8, and n is an integer of 0 to 3. [Chemical formula 3] Embedded image Embedded image Embedded image Embedded image Embedded image 2. The acrylic resin having a hydroxyl group (A)
The thermosetting topcoat composition according to claim 1, wherein the hydroxyl value is 10 to 300 mgKOH / g and the number average molecular weight is 1,500 to 40,000. 3. An alkoxysilyl group-containing acrylic copolymer (B) containing from 5 to 90% by weight of an alkoxysilyl group-containing monomer unit having a polymerizable double bond and an alkoxysilyl group in the molecule. The thermosetting topcoat composition according to claim 1, which is: 4. The partially hydrolyzed condensate (D) is methyl
A condensate obtained by partially hydrolyzing trimethoxysilane.
The thermosetting topcoat composition according to claim 1.