JPH10158574A - Fluororesin composition for paints - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive fluororesin composition for baking paint having a high luster of coating film, high durability, manifesting long term processing characteristics of bending by containing a specific fluorine based graft resin, and vinylidene fluoride based polymer. SOLUTION: The object composition having a wide variety of use, is obtained by containing (A) 100 pts. of the fluorine containing graft resin obtained by graft polymerizing 100 pts.wt. of a fluorine containing copolymer consisting of 20-70mol% of fluoro olefin based structural unit and 30-80mol% of carboxylic acid vinyl ester or vinyl ether compound and 1-300 pts. of a monomer mixture mainly consisting of (meth)acrylate, and (B) 10-500 pts. of the vinylidene fluoride based polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororesin composition for paints, and more particularly to a fluororesin composition for paints containing a fluorine-based graft resin and a polyvinylidene fluoride-based resin.

[0002]

2. Description of the Related Art Conventionally, fluororesin coatings utilizing the excellent weather resistance of a fluorocopolymer have been industrialized. At the center of this is the baking of a mixed resin of polyvinylidene fluoride and acrylic resin, forming a large market for coil coating applications. Further, a solvent-soluble fluorine-based copolymer having a cured site is synthesized (for example, JP-A-57-34107, JP-A-61-57609).
No. 1), and many applications have been made as weather-resistant paints in the fields of construction, automobiles, and the chemical industry. These fluorine-based copolymers are obtained by using chlorotrifluoroethylene, tetrafluoroethylene or vinylidene fluoride as a fluorine-based monomer and using a hydrocarbon-based monomer such as vinyl carboxylate or vinyl ether as a copolymerization component. The solubility in the solvent is increased.

However, since the polyvinylidene fluoride-based baked coating film has low gloss, it is not used for applications requiring high gloss, and a coating film made of a solvent-soluble fluororesin paint having a cured portion has a high gloss. However, its use was limited because of its high bending workability and high resin price. Even if polyvinylidene fluoride is blended with the conventionally known solvent-soluble fluororesin, the compatibility with each other is low and the bending workability is lowered. It is known that when an acrylic resin is blended with polyvinylidene fluoride, the glossiness of the coating film increases as the amount of the acrylic resin increases, but the weather resistance sharply decreases.

On the other hand, a fluorine-based graft resin obtained by graft-polymerizing various monomers to a fluorine resin (for example, Japanese Patent Application Laid-Open No. -41315, 61-24771
No. 7, Publication No. 62-295914).

[0005]

In view of the above, it has been desired to provide an inexpensive baking paint having a coating film having high gloss, high weather resistance, and long-term bending workability.

[0006]

Means for Solving the Problems The inventors of the present invention aimed at increasing the gloss of a coating film obtained from a baking-type paint composed of a vinylidene fluoride resin and an acrylic resin, with the aim of increasing the gloss of the coating film. The use of a high resin was examined, but it was found that a resin capable of obtaining a coating film having high gloss had poor weather resistance and reduced long-term bending workability. Therefore, when a method of blending a fluororesin having excellent weather resistance and high gloss with vinylidene fluoride resin was examined, the structural units based on a fluoroolefin and the structural units based on a monomer having an ethylenically unsaturated bond were mainly used. That the fluorine-based graft resin obtained by graft-polymerizing a (meth) acrylic acid ester onto the main chain has a high compatibility with vinylidene fluoride resin, and this is converted to vinylidene fluoride resin or vinylidene fluoride resin and acrylic resin. And found that the coating film formed from the obtained paint had high gloss, high weather resistance, and long-term bending workability, and reached the present invention.

That is, the present invention provides a fluorocopolymer [A] comprising a structural unit based on a fluoroolefin.
100 parts by weight of a fluorinated graft resin [B] obtained by performing graft polymerization in the presence of a monomer composition mainly composed of acrylonitrile and a (meth) acrylate, and a vinylidene fluoride polymer [C] 10 A fluororesin composition for coatings comprising from 500 to 500 parts by weight;
This is a fluororesin composition for paints, which contains an acrylate polymer.

Hereinafter, the present invention will be described in detail. In the structural unit based on the fluoroolefin of the fluorine-based copolymer [A] according to the present invention, at least one of the hydrogen atoms of ethylene is substituted with a fluorine atom, and the other one to three hydrogen atoms are optionally halogen (fluorine). , Chlorine, bromine), fluoromethyl groups, difluoromethyl groups, trifluoromethyl groups, and other substituted fluoroolefins, such as chlorotrifluoroethylene, tetrafluoroethylene, vinylidene fluoride, fluoride Examples thereof include vinyl, trifluoroethylene, hexafluoropropene, and hexafluoroisobutene, and chlorotrifluoroethylene is particularly preferable. These may be used in combination of two or more. The copolymerization ratio of the fluoroolefin in the fluorine-based copolymer [A] is not necessarily limited, but is not preferably 20 mol% or more, preferably 40 mol%, of the total amount of the monomers, since a decrease in weather resistance is not preferred.
Mol% or more, preferably 70 mol% or less, more preferably 60 mol% or less, in order to maintain solvent solubility.

The structural unit constituting the fluorine-based copolymer [A] according to the present invention is introduced mainly for the purpose of solubilizing the fluorine resin in a solvent, and the comonomer used for this purpose is carboxylic acid. Vinyl esters, vinyl ether compounds, olefins, allyl ether compounds and the like are preferably employed, and vinyl carboxylate is particularly preferred in order to maintain compatibility with the graft portion of the fluorine-based graft resin. As the carboxylic acid vinyl ester, specifically, a vinyl ester of an alicyclic or aromatic carboxylic acid which may have a branched chain of a fatty acid or a substituent having 2 to 22 carbon atoms, for example, acetic acid vinyl,
Vinyl propionate, vinyl butyrate, vinyl pivalate,
Examples include vinyl caproate, vinyl caprylate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, versatic vinyl 9-acid, versatic vinyl 10-acid, and vinyl benzoate. As the vinyl ether compound, for example, methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether,
Cyclohexyl vinyl ether and the like can be mentioned. Further, examples of the allyl ether include ethyl allyl ether, butyl allyl ether, benzyl allyl ether, allyl glycidyl ether, cyclohexyl allyl ether, and the like. The comonomer introduced for the purpose of solubilizing the solvent, such as vinyl carboxylate, vinyl ether compound, olefin, or allyl ether compound, accounts for 20 to 70 mol%, preferably 30 to 70 mol% of the total monomer amount. 60 mol%, more preferably 35 to 55
Mol%.

A monomer having a hydroxy group, a carboxyl group, an epoxy group or an amino group can be copolymerized for the purpose of introducing a crosslinking site or a graft polymerization initiation site into the fluorine-based copolymer [A]. Examples of the hydroxy group-containing monomer copolymerized in the fluorine-based copolymer [A] include allyl alcohol, ethylene glycol monoallyl ether, propylene glycol monoallyl ether,
Hydroxyalkyl allyl ethers having 2 to 8 carbon atoms such as hydroxybutyl allyl ether, alkylene glycol monoallyls having 4 to 40 carbon atoms such as diethylene glycol monoallyl ether and polyethylene glycol monoallyl ether. Ethers, hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, hydroxyalkyl vinyl ethers such as hydroxyhexyl vinyl ether, polyethylene glycol monovinyl ethers such as diethylene glycol monovinyl ether, crotonic acid-modified compounds such as hydroxyethyl crotonic acid And the like. These hydroxy group-containing monomers are not necessarily essential in the monomer composition for producing the fluorocopolymer [A], but are preferably 30 mol% or less of the total amount of monomers, More preferably, it is at most mol%. A coating film made of a fluorine-based graft resin prepared from the fluorine-based copolymer [A] produced in an amount exceeding 30 mol% is not preferred because water resistance and weather resistance are lowered.

A carboxyl group-containing monomer can be included in the monomer composition for the purpose of introducing a carboxy group into the fluorine-based copolymer [A]. Twelve unsaturated aliphatic carboxylic acids, for example, unsaturated carboxylic acids such as vinyl acetic acid, undecylenic acid, crotonic acid, acrylic acid and methacrylic acid. These carboxyl group-containing monomers are preferably at most 10 mol%, more preferably at most 5 mol%, based on the total amount of the monomers for producing the fluorocopolymer [A]. A coating film composed of a fluorine-based graft resin prepared from the fluorine-based copolymer [A] produced in an amount exceeding 10 mol% is not preferred because water resistance and weather resistance are lowered.

Further, a monomer containing an epoxy group or an amino group can be included in the monomer composition for the purpose of introducing an epoxy group or an amino group into the fluorine-based copolymer [A]. Examples thereof include allyl glycidyl ether, vinyl glycidyl ether, glycidyl (meth) acrylate and allylamine. These monomers are preferably at most 10 mol%, more preferably at most 5 mol%, of the total amount of monomers for producing the fluorocopolymer [A]. 10
A coating film composed of a fluorine-based graft resin prepared from the fluorine-based copolymer [A] manufactured in excess of mol% is not preferred because water resistance and weather resistance are lowered.

Further, a monomer having a peroxy group can be copolymerized for the purpose of introducing a graft polymerization initiation site into the fluorine-based copolymer [A]. A monomer having a peroxy group is copolymerized in the fluorine-based copolymer [A], and the peroxy group is used as a radical polymerization starting point,
It is graft-polymerized with a monomer such as (meth) acrylate. Here, examples of the monomer having a peroxy group include various unsaturated peroxyesters and peroxycarbonates, and specifically,
t-butyl peroxy methacrylate, di (t-butyl peroxy) fumarate, t-butyl peroxycrotonate, t-butyl peroxyallyl carbonate, t
Hexyl peroxyallyl carbonate, 1,1,
3,3-tetramethylbutyl peroxyallyl carbonate, t-butyl peroxymethallyl carbonate,
Examples thereof include 1,1,3,3-tetramethylbutyl peroxymethallyl carbonate, p-menthaneperoxyallyl carbonate, and p-menthaneperoxymethallyl carbonate. The copolymerization ratio in the monomer composition of these monomers having a peroxy group is not particularly limited,
It is 0.01 to 15 mol%, and it is preferable to use it in the range of 0.1 to 5 mol%. When the amount is less than 0.01 mol%, the amount of the graft starting point is insufficient, so that not only the graft reactivity is low, but also the molecular weight of the obtained graft resin becomes too high, so that the solubility may be poor. On the other hand, if it exceeds 15 mol%, the amount of the graft starting point is too large, and the weather resistance of the coating film made of the fluorine-based graft resin prepared from the obtained fluorine-based copolymer [A] becomes low, which is not preferable.

In order to directly introduce a graft polymerization initiation site into the fluorine-based copolymer [A], a monomer having two kinds of polymerizable groups, for example, allyl methacrylate can be copolymerized. . In this case, a polymerizable double bond can be introduced into the fluorine-based copolymer [A] by a one-stage polymerization operation, and can be immediately used for graft polymerization described later.

Further, an alkoxysilyl group can be introduced into the fluorine-based copolymer [A]. Specifically, vinyltrialkoxysilanes such as vinyltrimethoxysilane and vinyltriethoxysilane, and vinylmono (or divinylsilane) can be used. ) Monomers such as alkoxysilanes can be used for this purpose. These alkoxysilyl group-containing monomers are 10% of the monomer composition for producing the fluorocopolymer [A].
It is preferably at most 5 mol%, more preferably at most 5 mol%. A coating film composed of a fluorine-based graft resin prepared from the fluorine-based copolymer [A] produced in an amount exceeding 10 mol% is not preferred because water resistance and weather resistance are lowered.

The fluorine-based copolymer [A] according to the present invention
Is produced by copolymerizing a monomer mixture having an appropriately prepared composition. In the case where no peroxy group is contained, a fluorine-based copolymer [A] is further added to improve the graft ratio. It is preferable to introduce a polymerizable double bond by modification. The polymerization method is not particularly limited, and a known polymerization method can be employed, and examples thereof include solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. Solution polymerization in which the resin is obtained is particularly suitable. Examples of the solvent at this time include water and alcohol compounds, n-hexane, saturated hydrocarbons such as n-heptane, toluene,
Aromatic hydrocarbons such as xylene and ethylbenzene,
Fluorine such as 1,1-dichloro-1-fluoroethane, 3,3-dichloro-1,1,1,2,2-pentafluoropropane, ketone such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, Esters such as butyl acetate, and petroleum solvents such as mineral spirits, mineral terpene solvents, and isoparaffin solvents can be used. These may be used in combination of two or more.

Examples of the radical initiator usable here include diisopropyl peroxydicarbonate,
Di-n-propylperoxydicarbonate, di-2-
Dicarbonates such as ethylhexylperoxydicarbonate, or diacyl peroxides such as n-heptafluorobutylic peroxide, lauroylperoxypivalate, t-butyloxy neodecanoate, di-t-butyl peroxide, t Specific examples include alkyl peroxides such as -butylcumyl peroxide, and peroxyesters such as t-butylperoxypivalate and t-butylperoxyneodecanoate. When a monomer having a peroxy group is copolymerized in the fluorine-based copolymer [A], it is necessary to select a radical initiator that decomposes at a lower temperature than the peroxy group.

In order to modify the fluorine-based copolymer [A] to introduce a polymerizable double bond, the fluorine-based copolymer [A] must be prepared in advance.
The reaction is carried out by reacting the functional group introduced into the polymer with a functional group of a functional monomer having a polymerizable double bond. The polymerizable double bond is located in the side chain, and the number of double bonds in the molecule is preferably 15% or less of the number of structural units based on all monomers.

The type of the functional monomer differs depending on the functional group previously introduced into the fluorine-based copolymer [A]. For example, when the fluorine-based copolymer [A] has a hydroxy group, Is used. For example, isocyanate methacrylate and isocyanate ethyl methacrylate are preferable, and an unsaturated group-containing monoisocyanate compound prepared from a readily available diisocyanate compound and an unsaturated alcohol can also be used. In this case, the purpose is achieved by forming a urethane bond between the hydroxy group and the isocyanate group. Similarly, when having an epoxy group,
Using a monomer having a carboxyl group as described above such as (meth) acrylic acid, an ester bond can be formed to introduce a polymerizable double bond. When the compound has a carboxyl group, a polymerizable double bond can be introduced by forming an ester bond with a functional monomer having an epoxy group, for example, allyl glycidyl ether or glycidyl methacrylate. These denaturing reactions can be carried out simply by dissolving the fluorine-based copolymer [A] and the functional monomer in an appropriately selected solvent and heating. Further, the reaction can be promoted by heating in the presence of a catalyst such as an acid or an amine compound.

The monomer composition mainly comprising (meth) acrylic acid ester used for the polymerization of the fluorine-based graft resin [B] according to the present invention is used for producing an acrylic resin for paint. Acrylic acid esters are preferable, but an alkyl group having 1 to 22 carbon atoms which may have a branch, a cycloalkyl group which may have a substituent, or an aromatic group and a (meth) acrylic group composed of a (meth) acryloyl group Acid ester, specifically exemplified by:
Methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl acrylate, tridecyl acrylate, Lauryl acrylate, benzyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, ethylhexyl methacrylate, methacrylic acid
Examples include n-octyl, isooctyl methacrylate, nonyl methacrylate, tridecyl methacrylate, lauryl methacrylate, benzyl methacrylate, and isobornyl methacrylate. Further, an amino group-containing (meth) acrylate having an amino group in the molecule may be used. For example, aminoethyl (meth) acrylate, N-methylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate Acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-methylethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate , N, N-
Diethylaminopropyl (meth) acrylate, N, N
-Diethylaminohexyl (meth) acrylate and the like can be used. Further, the (meth) acrylate may be a hydroxy group-containing (meth) acrylate, and may have a branched alkyl group having 1 to 22 carbon atoms, may have a hydroxy group, and may have another substituent. A cycloalkyl group or an aromatic group and a (meth) acryloyl group.
Hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, or (meth) acrylic acid esters of polyhydric alcohols, for example, polyethylene glycol mono (meth) acrylate; Examples thereof include polypropylene glycol mono (meth) acrylate, poly (ethylene glycol-propylene glycol) mono (meth) acrylate, polytetramethylene glycol mono (meth) acrylate, and glycerol mono (meth) acrylate. Furthermore, it is also possible to use (meth) acrylates for others.

In the monomer composition mainly comprising (meth) acrylate used for the polymerization of the fluorine-based graft resin [B] according to the present invention, other copolymerizable monomers may be used in combination. Examples thereof include acrylonitrile, styrene as an aromatic vinyl compound, and ethylene, propylene, and butene as olefins.
Further, as other copolymerizable monomers, fluoroolefins, carboxylic acid vinyl esters, vinyl ether compounds, and hydroxy group-containing allyl ether compounds exemplified as monomers used in the polymerization of the fluorine-based copolymer [A] And vinyl ether compounds.

In the production of the fluorine-based graft resin [B] according to the present invention, the fluorine-based copolymer [A] 10
Grafting reaction is carried out in the presence of 0 part by weight and 1 to 300 parts by weight, preferably 10 to 200 parts by weight of a monomer composition mainly composed of (meth) acrylic acid ester. If the amount is less than 1 part by weight, the compatibility with the vinylidene fluoride polymer [C] is low, so that the gloss of the coating film does not increase and the fluorine-based graft resin [B] also contributes to improvement in bending workability. Is difficult to obtain, and if it exceeds 300 parts by weight, the fluorine content is decreased, and the weather resistance of the coating film made of the prepared fluorine-based graft resin [B] is undesirably reduced.

The reaction form of the graft reaction according to the present invention is not particularly limited, but the reaction is carried out in the presence of a fluorine-based copolymer [A] dissolved in a solvent and a monomer mainly composed of (meth) acrylate. Solution polymerization is preferred. In the polymerization method, when the fluorine-based copolymer [A] has a peroxy group, graft polymerization is performed with a peroxy group as a starting point without adding a polymerization initiator separately. It is only necessary to adopt a method according to the polymerization of the fluorine-based copolymer [A] by adding an agent. As generally seen in the case of graft polymerization, the fluorine-based graft resin [B] according to the present invention involves a polymer comprising a monomer mainly containing a (meth) acrylic ester, and a fluorine-based copolymer. The amount of the peroxy group or the amount of the polymerizable double bond, the type of the monomer, the composition, the type and the amount of the initiator contained in [A], and other polymerization conditions vary, but such a polymer is removed. It can be used for preparing the fluororesin composition for paints of the present invention without any.

The molecular weight of the fluorine-based graft resin [B] according to the present invention is preferably from 1,000 to 200,000 (number average molecular weight; in terms of styrene), and from 5,000 to 1
00,000 is more preferred. If it is less than 1,000, the weather resistance and flexibility of the coating film prepared from the fluorine-based graft resin [B] decrease, and if it exceeds 200,000, the solubility decreases and the graft polymerization becomes difficult. Not preferred.

The vinylidene fluoride-based polymer according to the present invention is a polymer mainly composed of structural units based on vinylidene fluoride, and is used for baking paint, although the structure, molecular weight and physical properties associated therewith vary depending on the polymerization conditions. Homopolymers or copolymers are preferred. As a homopolymer of polyvinylidene fluoride, Audimont's Hyler 500
0, Elf Atochem Kainer 500, etc., but not limited to these products. Also, vinyl fluoride,
Trifluoroethylene, chlorotrifluoroethylene,
Tetrafluoroethylene, hexafluoropropylene,
A vinylidene fluoride-based polymer obtained by copolymerizing one or more kinds of fluorine-containing compounds selected from hexafluoroisobutene, hexafluoroacetone and the like with vinylidene fluoride can also be used.

The fluororesin composition for paints of the present invention contains about 10 to 500 parts by weight of vinylidene fluoride polymer [C] per 100 parts by weight of fluorine graft resin [B], preferably 50 to 50 parts by weight. About 200 parts by weight are blended. If the amount of the vinylidene fluoride polymer is less than 10 parts by weight, the high weather resistance and chemical resistance of the polyvinylidene fluoride cannot be sufficiently exhibited. If the amount exceeds 500 parts by weight, the fluorine-based graft resin [B] is blended. This is not preferable because no improvement in the gloss of the coating film is observed.

In the present invention, in addition to the fluorine-based graft resin [B] and the vinylidene fluoride-based polymer [C], a (meth) acrylate-based polymer may be further blended. As the (meth) acrylate-based polymer, a resin obtained by polymerizing a monomer composition mainly containing (meth) acrylate used in the polymerization of the fluorine-based graft resin [B] by a known method. Can be used. The composition is not particularly limited, but the content of methyl methacrylate is preferably at least 40 mol% from the viewpoint of compatibility. In addition, since resins having similar compositions are commercially available as acrylic resins for coatings, these can be appropriately selected and used. The blending amount of the (meth) acrylate polymer is preferably 200 parts by weight or less, more preferably 150 parts by weight or less, based on 100 parts by weight of the fluorine-based graft resin [B]. If it exceeds 200 parts by weight, the weather resistance of the prepared coating film is undesirably reduced.

The fluororesin composition for a paint of the present invention is used together with a solvent. As the solvent, those used as a latent solvent for polyvinylidene fluoride are employed. Such include, for example, methyl isobutyl ketone,
Butyl acetate, cyclohexanone, diacetone alcohol, diisobutyl ketone, butyrolactone, etraethyl urea, isophorone, triethyl phosphate,
Carbitol acetate, propylene carbonate, dimethyl phthalate and the like. Along with this, a solvent for polyvinylidene fluoride, for example, acetone,
It can be used as a mixed solvent together with tetrahydrofuran, methyl ethyl ketone, dimethylformamide, dimethylacetamide, tetramethylurea, trimethylphosphate and the like, and non-solvents such as pentane, methanol, hexane, benzene, isopropyl alcohol, ethanol, xylene and decane.

The fluororesin composition for a coating material of the present invention can be made into a coating material in the same manner as a normal resin, and a pigment or a dye can be appropriately added. At that time, an ultraviolet absorber, a light stabilizer, Rust inhibitors, dispersants, anti-dripping agents, fungicides, leveling agents and the like can also be added.

Further, when forming a paint, other resins, for example, a fluorine-based polyol, another fluorine-containing resin having an alkoxysilane, acrylic silicone, an acrylic-based polyol,
Polyvinyl esters, silicone compounds, polyalkylene glycols, alkyd resins and the like can also be added as appropriate.

Hereinafter, the present invention will be described in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the examples, “parts” means “parts by weight” unless otherwise noted.

[0032]

【Example】

[Synthesis Example 1] 212 g of vinyl acetate (2 parts of all monomers used to polymerize the fluorine-based copolymer [A]) in a 3.4-liter SUS autoclave equipped with an electromagnetic stirrer.
8 mol%, hereinafter the same. ), Versatic Vinyl 9 Acid 2
43 g (15 mol%), ethylene glycol monoallyl ether 32 g (3.5 mol%), t-butyl peroxyallyl carbonate 10 g (1 mol%), undecylenic acid 8 g (0.5 mol%), t-butyl peroxy 5 g of pivalate and 10 g of celite were charged, and the mixture was degassed and replaced three times with nitrogen gas. After degassing, 533 g (52 mol%) of chlorotrifluoroethylene and 385 g of xylene were charged, and polymerization was carried out at 55 ° C. for 18 hours. After the polymerization, the mixture was filtered to obtain 910 g of a fluorine-based copolymer [A] as a resin solid content.
Xylene solution was obtained.

Next, in a SUS autoclave having an internal capacity of 2.0 liters equipped with an electromagnetic stirrer, with respect to a solid content of 300 g of the xylene solution of the fluorocopolymer [A], 220 g of methyl methacrylate, 70 g of cyclohexyl methacrylate, 10 g of ethyl methacrylate,
t-Dodecylmercaptan (0.01 g) and xylene (total weight: 600 g) were charged, and graft polymerization was performed at 100 ° C. for 8 hours. After the polymerization, the content was taken out and filtered, and the concentration was adjusted to obtain a varnish of a transparent fluorine-based graft resin [B] having a solid content of 50%. The hydroxy value of the obtained fluorine-based graft resin was 15 mgKOH / g, the acid value was 2.0 mgKOH / g, and the molecular weight was 19,000 in terms of styrene equivalent number average molecular weight.

[Synthesis Example 2] Content with electromagnetic stirrer
Vinyl acetate 21 in a 4 liter SUS autoclave
2 g (28 mol%), 316 g of versatic vinyl 9 acid
(19.5 mol%), 20 g (2 mol%) of t-butyl peroxyallyl carbonate, 8 g of undecylenic acid
(0.5 mol%), t-butyl peroxypivalate 5
g, Celite 10g, and degassed and replaced with nitrogen gas.
After degassing repeatedly, chlorotrifluoroethylene 5
33 g (52 mol%) and 385 g of xylene were charged.
Polymerization was carried out at 5 ° C. for 18 hours. After the polymerization, the mixture was filtered to obtain 925 g of a xylene solution of a fluorine-based copolymer [A] as a resin solid content.

In a 2.0-liter SUS autoclave equipped with a magnetic stirrer, 220 g of methyl methacrylate and 70 g of cyclohexyl methacrylate were added to a solid content of 180 g of the xylene solution of the fluorocopolymer [A].
g, 10 g of butyl methacrylate, 0.01 g of t-dodecyl mercaptan, and xylene in a total weight of 480 g, and graft polymerization was carried out at 100 ° C. for 8 hours.
After the polymerization, the content was taken out and filtered, and the concentration was adjusted to obtain a varnish of a transparent fluorine-based graft resin [B] having a solid content of 50%. The acid value was 1.6 mg KOH / g, and the molecular weight was 22,000 in terms of styrene. Hydroxy groups are not substantially contained in the obtained resin except as a carboxyl group.

[Synthesis Example 3] Content with electromagnetic stirrer
In a 4 liter SUS autoclave, 177 g (28 mol%) of ethyl vinyl ether, 206 g (19.5 mol%) of cyclohexyl vinyl ether, 20 g (2 mol%) of t-butylperoxyallyl carbonate, 8 g (0.5 mol%) of undecylenic acid , 5 g of t-butyl peroxypivalate and 10 g of celite, and after degassing by repeating degassing and replacement with nitrogen gas three times, 510 g (50 mol%) of chlorotrifluoroethylene and 420 g of xylene
And polymerized at 55 ° C. for 18 hours. After the polymerization, the mixture was filtered to obtain 915 g of a xylene solution of a fluorine-based copolymer [A] as a resin solid content.

In a 2.0-liter autoclave made of SUS with an electromagnetic stirrer, 220 g of methyl methacrylate and 70 g of cyclohexyl methacrylate were added to a solid content of 300 g of the xylene solution of the fluorocopolymer [A].
g, hydroxyethyl methacrylate 10 g, t-dodecyl mercaptan 0.01 g, xylene total weight 600
g, and graft polymerization was performed at 100 ° C. for 8 hours. After the polymerization, the content was taken out and filtered, and the concentration was adjusted to obtain a varnish of a transparent fluorine-based graft resin [B] having a solid content of 50%. The hydroxy value in the obtained resin was 10.0 mgKOH / g, and the acid value was 1.7 mgKOH / g.
g, the molecular weight is 16,000 as a number average molecular weight in terms of styrene.
It was 0.

[Synthesis Example 4] Contents with electromagnetic stirrer
Vinyl acetate 21 in a 4 liter SUS autoclave
2 g (28 mol%), 243 g of versatic vinyl 9 acid
(15 mol%), ethylene glycol monoallyl ether 34 g (4.5 mol%), undecylenic acid 8 g (0.
5 mol%), 5 g of t-butyl peroxypivalate, and 10 g of celite, and after degassing and repeating degassing and replacement with nitrogen gas three times, 533 g of chlorotrifluoroethylene
(52 mol%) and 385 g of xylene were charged and polymerized at 55 ° C. for 18 hours. After the polymerization, the mixture was filtered to obtain 910 g of a xylene solution of a fluorine-based copolymer [A] as a resin solid content.

Next, 300 g of the solid content of the xylene solution of the fluorocopolymer [A] was placed in a 2.0-liter SUS autoclave equipped with a magnetic stirrer, and xylene was added to reduce the xylene content to 300 g. Then, 14 g of isocyanate ethyl methacrylate was charged, and after degassing, the temperature was raised to 80 ° C. and the mixture was stirred for 7 hours to introduce a polymerizable double bond into the fluorine-based copolymer [A].

Further, 220 g of methyl methacrylate, 70 g of cyclohexyl methacrylate, 10 g of hydroxyethyl methacrylate, 0.1 g of t-dodecylmercaptan.
1 g and 300 g of xylene were injected, and graft polymerization was performed at 100 ° C. for 8 hours. After the polymerization, the content was taken out and filtered, and the concentration was adjusted to obtain a varnish of a transparent fluorine-based graft resin [B] having a solid content of 50%. The hydroxy value of the obtained fluorine-based graft resin was 7 mgKOH / g, the acid value was 1.0 mgKOH / g, and the molecular weight was 18,000 as a number average molecular weight in terms of styrene.

Example 1 120 parts of Audimont's Hylar 5000 as vinylidene fluoride, 120 parts of Rohm and Haas, based on 100 parts of resin solid content of fluorinated graft resin [B] varnish obtained in Synthesis Example 1 Methacrylate-based copolymer paraloid B44 40
, 90 parts of xylene and 290 parts of isophorone were added and mill-dispersed to obtain a white enamel.

Then, the thickness is 0.8 mm with a bar coater.
And baked at 270 ° C. for 2 minutes to obtain a white coating having a thickness of about 40 μm. The gloss of the obtained coating film was measured as 60-degree specular gloss. The accelerated weather resistance data was measured as a gloss retention by performing a sunshine weatherometer test for 5000 hours. Further, a bending test was performed after a heating test of 80 ° C. for 7 days was performed on the coating film. In the bending test, an aluminum plate having the same thickness (0.8 mm) was sandwiched inward in accordance with JIS-G3312, and the entire aluminum substrate was bent with the coating film on the outside.
A method for evaluating the resistance was used. As the evaluation, when the number of inner aluminum plates was reduced, the minimum number of aluminum plates that did not cause cracks in the coating film at the bent portion was displayed. For example, when three sheets were placed inside and bent, no crack was found, and when two sheets were cracked, 3T was used. Table 1 shows the results.

[0043]

[Table 1]

[Examples 2 to 5] The varnish of the fluorine-based graft resin [B] obtained in Synthesis Examples 2 to 4 was treated in the same manner as in Example 1 as a vinylidene fluoride-based polymer such as Hyler 5000, Methacrylate copolymer B4
4. Table 1 shows titanium oxide CR90, xylene and isophorone.
And dispersed in a mill to obtain a white paint enamel.

Next, a white coat having a thickness of about 40 μm was obtained by coating the aluminum plate with a bar coater and baking it at 270 ° C. for 2 minutes in the same manner as in Example 1. Gloss measurement, accelerated weather resistance test, and bending test were performed on the obtained coating film in the same manner as in Example 1. The results are summarized in Table 1.

[Comparative Example 1] Hylar 5000, methacrylate copolymer B44, titanium oxide CR90, xylene, and isophorone were added in the proportions shown in Table 1 without adding a fluorine-based graft resin, followed by mill dispersion. Thus, a white paint enamel was obtained.

Next, the aluminum plate was coated with a bar coater and baked at 270 ° C. for 2 minutes to give a film thickness of about 40.
A micron white coating was obtained. Gloss measurement, accelerated weather resistance test, and bending test were performed on the obtained coating film in the same manner as in Example 1. Table 1 shows the results.

[Comparative Example 2] 100 parts of the fluorine-based copolymer [A] produced in Synthesis Example 1 was added to Hylar 5000,
Methacrylate copolymer B44, titanium oxide C
R90, xylene and isophorone were added in the proportions shown in Table 1 and dispersed in a mill to obtain a white paint enamel.

Next, the aluminum plate was coated with a bar coater and baked at 270 ° C. for 2 minutes to give a film thickness of about 40.
A micron white coating was obtained. Gloss measurement, accelerated weather resistance test, and bending test were performed on the obtained coating film in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 3 100 parts of the fluorocopolymer [A] produced in Synthesis Example 3 was added to Hylar 5000,
Methacrylate copolymer B44, titanium oxide C
R90, xylene and isophorone were added in the proportions shown in Table 1 and dispersed in a mill to obtain a white paint enamel.

Next, the aluminum coating was applied on an aluminum plate with a bar coater and baked at 270 ° C. for 2 minutes.
A micron white coating was obtained. Gloss measurement, accelerated weather resistance test, and bending test were performed on the obtained coating film in the same manner as in Example 1. Table 1 shows the results.

[0052]

As is apparent from the results of the respective examples, the coating film prepared by applying the coating material prepared from the fluororesin composition for a coating material of the present invention to a base material is, as is clear from the results of each of the examples, a conventional polyvinylidene fluoride and acrylic resin. Since it has a remarkably high gloss as compared with a coating film obtained from a baking coating made of a resin and can maintain bending workability for a long time, the fluororesin composition for coating has a remarkable effect of having a wide range of applications. Play.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kentaro Tsutsumi 2805 Imafukunakadai, Kawagoe-shi, Saitama Central Chemical Glass Co., Ltd.

Claims (10)

[Claims] 1. A polymer obtained by performing a graft polymerization in the presence of a monomer composition mainly comprising a fluorine-based copolymer [A] containing a structural unit based on a fluoroolefin and a (meth) acrylate ester. A fluororesin composition for paints, comprising 100 parts by weight of a fluorine-based graft resin [B] and 10 to 500 parts by weight of a vinylidene fluoride-based polymer [C]. 2. Graft polymerization in the presence of 100 parts by weight of a fluorine-based copolymer [A] and 1 to 300 parts by weight of a monomer composition mainly composed of a (meth) acrylate ester, wherein the fluorine-based graft resin [B] is 100 parts by weight. The fluororesin composition for paints according to claim 1, which is a fluorine-based graft resin [B] obtained by performing the following. 3. A fluorine-containing copolymer [A] comprising 20 to 70 mol% of a structural unit based on a fluoroolefin and 30 to 80 mol% of a structural unit based on a vinyl carboxylate or vinyl ether compound. Item 1
3. The fluororesin composition for a coating according to any one of the above items. 4. The fluorine-based copolymer [A] further contains 30 mol% or less of a structural unit based on a monomer having a hydroxy group or a carboxyl group.
3. The fluororesin composition for paints described in any one of 3. 5. The fluorine-based copolymer [A] has a structural unit based on a monomer having a peroxy group in an amount of 0.01 to 15 or more.
The fluororesin composition for paints according to any one of claims 1 to 4, wherein the composition contains mol%. 6. The fluorine-based copolymer [A] further has a polymerizable double bond in a side chain, and the number of polymerizable double bonds in the molecule is 15% of the number of structural units based on all monomers. % Or less, the fluororesin composition for paints according to claim 1. 7. The fluorine-based copolymer [A], wherein the polymerizable double bond is bonded to the main chain through at least one of a urethane bond and an ester bond. Fluororesin composition for paints. 8. The method according to claim 1, wherein the fluorine-based graft resin [B] has a hydroxy group or a carboxyl group in a portion or a graft portion based on the fluorine-based copolymer [A]. Fluororesin composition for paints. 9. The fluororesin composition for paints according to claim 1, further comprising 200 parts by weight or less of a (meth) acrylate polymer. 10. The fluororesin composition for paints according to claim 1, further comprising at least a solvent in an amount capable of forming a uniform composition when the fluororesin composition for paints is baked. A fluororesin composition for paints, characterized by that: