JP3295946B2 - Method for forming a coating film with excellent flexibility - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for forming a coating film having excellent flexibility using a fluorine-containing copolymer.
More specifically, a fluorine-containing copolymer obtained by copolymerizing a monomer having at least two ethylenically unsaturated double bonds (hereinafter abbreviated as a polymerizable unsaturated group) in a molecule is used. The present invention relates to a method for forming a coating film having improved flexibility, comprising the steps of:

[0002]

2. Description of the Related Art Fluorine-containing copolymers have excellent weather resistance and, due to their characteristics, are mainly used as topcoats for various substrates and undercoat films.

[0003] Among these various uses, there are many cases where a high degree of flexibility is required for a top coat film. Generally, as one method of increasing the flexibility of the coating film,
Although it is known to increase the molecular weight of the resin to be used, in the case of a fluorine-containing copolymer, there is a problem that it is difficult to sufficiently increase the molecular weight even according to an ordinary production method.

[0004]

SUMMARY OF THE INVENTION However, the present inventors have eagerly started research in order to solve the above-mentioned problems.

[0005] Accordingly, an object of the present invention is to provide a method for forming a coating film having excellent flexibility by using a fluorine-containing copolymer having a high molecular weight. The present inventors have conducted intensive studies in order to solve such a problem, and as a result, using a monomer having at least two polymerizable unsaturated groups in the molecule as one of copolymers, Using a fluorine-containing copolymer having a high molecular weight obtained by copolymerizing a vinyl monomer and other copolymerizable monomers, it has been found that a coating film having excellent flexibility can be formed, The present invention has been completed.

[0006]

That is, the present invention relates to a method for preparing a fluorinated vinyl monomer (a) and a monomer having at least two ethylenically unsaturated double bonds in a molecule in an organic solvent. (B) overcoating a paint containing a fluorine-containing copolymer obtained by copolymerizing the monomer (a) and another monomer (c) copolymerizable with the monomer (b) An object of the present invention is to provide a method for forming a coating film having excellent flexibility, which is used as a paint.

Hereinafter, the configuration of the present invention will be described in detail. First, as the fluorine-containing vinyl monomer (a) used in the present invention, vinyl fluoride, vinylidene fluoride,
Trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene, hexafluoropropylene, trifluoromethyl trifluorovinyl ether, pentafluoroethyl trifluorovinyl ether or heptafluoro Perfluoroalkyl perfluorovinyl ethers such as propyl trifluorovinyl ether are particularly representative, and especially, tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene or hexafluoroethylene. The use of fluoropropylene is preferred.

[0008] These fluorine-containing vinyl monomers (a)
It goes without saying that they may be used alone or in combination of two or more. The ratio of the fluorine-containing vinyl monomer (a) used is 15 to 15 with respect to the total amount of the monomer (a) and the copolymerizable monomer (c) as described later. It should be controlled to be 70% by weight, preferably 30-60% by weight.

When the proportion of the monomer (a) is less than 15% by weight, it is difficult to obtain a material having sufficient weather resistance. In either case, the solvent solubility of the resulting fluorinated copolymer decreases, which is not preferable.

Next, another monomer capable of copolymerizing with the fluorine-containing vinyl monomer (a) and the monomer (b) having at least two polymerizable unsaturated groups in the molecule as described below. As the isomer (c), that is, the copolymerizable monomer (c), of course, any copolymerizable monomer may be used as long as it has copolymerizability with these monomers (a) and (b). However, if only those representatives are exemplified,

First, among these, particularly typical examples of the hydroxyl group-containing vinyl monomer (d) include 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether,
Hydroxyalkyl vinyl ethers such as 4-hydroxybutyl vinyl ether, 3-hydroxybutyl vinyl ether, 2-hydroxy-2-methylpropyl vinyl ether, 5-hydroxypentyl vinyl ether and 6-hydroxyhexyl vinyl ether;

In addition, methyl vinyl ether, ethyl ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether,
Alkyl vinyl ethers or substituted alkyl vinyl ethers such as 2-ethylhexyl vinyl ether, chloromethyl vinyl ether, chloroethyl vinyl ether, benzyl vinyl ether or phenylethyl vinyl ether;

Cycloalkyl vinyl ethers such as cyclopentyl vinyl ether, cyclohexyl vinyl ether or methylcyclohexyl vinyl ether; vinyl acetate, vinyl propionate, vinyl isobutyrate, vinyl caproate, vinyl caprylate, vinyl caprate,
Vinyl laurate, such as aliphatic carboxylic acid vinyl such branched aliphatic carboxylic acids or vinyl stearate branched aliphatic carboxylic acid vinyl, branched aliphatic carboxylic acids vinyl C _10, C ₁₁ of C _9;

Vinyl esters of carboxylic acid having a cyclic structure, such as vinyl cyclohexylcarboxylate, vinyl methylcyclohexylcarboxylate, vinylbenzoate or vinyl p-tert-butylbenzoate; α-vinyl esters such as ethylene, propylene or butene-1; Olefins;
Various halogenated olefins other than fluoroolefins, such as vinyl chloride or vinylidene chloride; aromatic vinyl compounds such as styrene, α-methylstyrene or vinyltoluene;

There are methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate or cyclohexyl methacrylate; and acrylates such as methyl acrylate, ethyl acrylate butyl acrylate or cyclohexyl acrylate.

In addition to the copolymerizable monomers described above, if necessary, a monomer containing a silyl group, a monomer containing an epoxy group, and a monomer containing an amino group may be used. Such monomers or monomers containing an acid group can also be used.

Particularly representative examples of such monomers include vinyltrimethoxysilane, vinyltripropoxysilane, vinylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) silane, allyltrimethoxysilane, trimethoxysilyl. Ethyl vinyl ether, triethoxyethylsilylvinylether, methyldimethoxysilylethylvinylether, trimethoxysilylpropylvinylether, triethoxysilylpropylvinylether, methyldiethoxysilylpropylvinylether, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meta) ) A hydrolyzable silyl group such as acryloyloxypropyltriethoxysilane or γ- (meth) acryloyloxypropylmethyldimethoxysilane Yutan amount of body like;

Glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate or (meth)
Epoxy group-containing monomers such as allyl glycidyl ether; N-dimethylaminoethyl (meth) acrylamide, N-diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide or N-diethylaminopropyl (meth) acrylamide Amino-containing unsaturated monomers containing an amino group such as

Dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate or diethylaminoethyl (meth) acrylate; tert-butylaminoethyl (meth) acrylate, tert-butylaminopropyl (meth) acrylate, aziridini Amino group-containing monomers such as ethyl (meth) acrylate, pyrrolidinylethyl (meth) acrylate or piperidinylethyl (meth) acrylate;

Or (meth) acrylic acid, crotonic acid,
Examples include carboxyl group-containing monomers such as itaconic acid, maleic acid or fumaric acid. Among these copolymerizable monomers, at least one selected from the group consisting of carboxylic acid vinyl esters, (substituted) alkyl vinyl ethers, cycloalkyl vinyl ethers and hydroxyalkyl vinyl ethers from the viewpoint of increasing the polymerization yield. It is particularly desirable to use one compound.

The monomer (b) having at least two polymerizable unsaturated groups in the molecule, that is, the polyfunctional monomer (b) used in the present invention is particularly representative. By way of example only, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene,
1,8-diene-2,2,7,7-tetramethylnonane, 1,8-dodecane or 1,9-diene-3,7
- di (tert- butyl) -4-hydroxy - decane, such as, C ₄ -C ₂₀ comprising diolefins;

1,4-butanediol divinyl ether, 1,6-hexanediol diallyl ether,
7-decanediol divinyl ether, 1,6-diol-3-ethoxy-4- (3-hydroxypropoxy)
Hexane divinyl ether, 1,9-diol-4,4
(Substituted) alkyl diol dialkenyl ethers, such as dibutyldecane vinyl allyl ether or diethylene glycol divinyl ether;

Divinyl adipate, divinyl sebacate, diallyl sebacate, 1-
(Substituted) alkyldicarboxylic acid dialkenyl esters such as ethylvinyl adipate vinyl allyl ester, 2-ethoxyadipate divinyl ester, 2-cyclohexyladipate diallyl ester or 2- (4-hydroxybenzyl) sebacate divinyl ester; divinyl Benzene, divinyltoluene or 4- (2-
Dialkenyl arenes, such as vinylethyl) styrene;

Aromatic diol dialkenyl ethers such as 3,5-dihydroxy-ethylbenzenedivinyl ester or 3,5-di (3-hydroxypropyl) benzenedivinyl ether; divinyl phthalate, diallyl isophthalate or 5-ethyl Aromatic dicarboxylic acid dialkenyl esters such as isophthalic acid divinyl ester; vinyl alcohol vinyl ether, vinyl alcohol allyl ether, 2-hydroxyethyl (meth) acrylate vinyl ether,
Alkenyl ethers of hydroxyl group-containing vinyl monomers such as hydroxyethyl (meth) acrylate allyl ether, 2-hydroxypropyl (meth) acrylate allyl ether or 3-hydroxypropyl (meth) acrylate vinyl ether; vinyl (meth) acrylate , Allyl (meth) acrylate, allyl maleate,
In addition to alkenyl esters of carboxyl group-containing vinyl monomers such as monovinyl itaconate or divinyl itaconate,

1,8-diene-4-allyl-nonane, glycerin divinyl ether, 1,9-diene-3- (4
-Vinylbutyl) -6-phenylethoxy-decane, glycerin trivinyl ether, glycerin diallyl ether, glycerin triallyl ether, glycerin vinyl allyl ether, trimellitic acid divinyl ester,
Trivinyl trimellitate, diallyl trimellitate or triallyl trimellitate are also included.

Among these various monomers (b), the use of alkyl diol divinyl ethers and alkyl dicarboxylic acid divinyl esters is particularly desirable from the viewpoint of copolymerizability.

These monomers (b) may be used alone or in combination of two or more. The amount of the monomer (b) used is such that the fluorinated vinyl monomer (a) listed above, the polyfunctional monomer (b) and the copolymerizable monomer are used. The total amount of the three essential monomers consisting of the monomer (c) is 1,
000 g, the polymerizable unsaturated group in the monomer (b) is 0.004 to 2 with respect to 1,000 g.
In such a ratio as to be equivalent, more preferably 0.02-
It is desirable that the ratio be 0.4 equivalent.

If the amount of the monomer (b) is less than 0.004 equivalent, it is difficult to obtain a fluorine-containing copolymer having a sufficiently high molecular weight, while if it is more than 2 equivalents. In any case, a problem such as gelation is caused at the time of polymerization, which is not preferable in any case.

As a method for carrying out copolymerization using the above-mentioned respective monomer components, a known method such as bulk polymerization, solution (pressure) polymerization, suspension polymerization or emulsion polymerization in the presence of a radical polymerization initiator is used. Although the polymerization method can be applied, the solution polymerization method is the simplest.

The radical polymerization initiator used in this case includes acetyl peroxide, benzoyl peroxide, lauroyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, di-tert. Peroxides such as -butyl peroxide, dicumyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy octoate, tert-butyl peroxy acetate or tert-butyl peroxy pivalate;

Azobisisobutyronitrile, dimethyl-
An azo compound such as 2,2 ′ azobis (2-methylpropionate) or azobisisovaleronitrile is particularly typical.

The organic solvent used in the polymerization includes toluene, xylene, cyclohexane, n-
Hydrocarbons such as hexane, octane or mineral spirit; esters such as methyl acetate, ethyl acetate, butyl acetate or ethylene glycol monoethyl ether acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone or cyclohexanone;

Amide systems such as dimethylformamide, dimethylacetamide or N-methylpyrrolidone; or methanol, ethanol, n-propanol, is
An alcoholic solvent such as o-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol or ethylene glycol monoalkyl ether, or a mixture thereof is particularly typical.

Of the thus obtained fluorine-containing copolymers according to the method of the present invention, those having a hydroxyl group can of course be formed into a film by using a curing agent by a conventionally known method. .

As the curing agent, any of conventionally known curing agents can of course be used, but if only typical ones are exemplified, tolylene diisocyanate, Diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4- (or -2,6-) diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate) or 1,3- Diisocyanates such as di (isocyanatomethyl) cyclohexane; triisocyanates such as 4-isocyanatomethyloctamethylene diisocyanate; Polyisocyanate resins obtained by reacting a polyhydroxy compound such as lene glycol, propylene glycol, neopentyl glycol, trimethylolpropane or a hydroxyl group-containing polyester; burettes obtained by reacting diisocyanates with water as described above and water Polyisocyanate resins having a bond; or polyisocyanate resins having an isocyanurate ring obtained by cyclopolymerization of various diisocyanates as described above;

Methyl etherified methylol melamine, n-
Amino resins such as butyl etherified methylol melamine or n-butyl etherified benzoguanamine;

Further, various isocyanates or polyisocyanate resins as described above are blocked isocyanates obtained by blocking with an active hydrogen compound such as alcohol, phenol, methyl ethyl ketoxime or ε-caprolactam. Polyalkoxy metal alkoxides such as tetrabutoxyethane, tributoxyaluminum or tetrabutoxyzirconium; polyvalent metal alkoxides as described above are reacted with various chelating agents such as acetylacetone or ethyl acetoacetate. Obtained polyvalent metal chelate compounds; or polycarboxylic anhydrides such as trimellitic anhydride or pyromellitic anhydride.

When such a curing agent is blended, the amount of the curing agent is 1 to 100 parts by weight based on 100 parts by weight of the solid content of the fluorine-containing copolymer solution.
A range within the range of parts by weight is appropriate.

If the amount of the curing agent is small, it is difficult to obtain a sufficiently cured coating film. On the other hand, if the amount is too large, the obtained coating film tends to be brittle. .

The fluorine-containing copolymer obtained as described above is most effective as it is as a clear coating film, but it can be used in a form to which a coloring agent is added if necessary.

Further, if necessary, various resins, solvents and the like, flow control agents, color separation inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, and the like; It is, of course, possible to add various known and commonly used additives.

If only typical representative examples of such colorants are given, dyes, organic pigments, indefinite pigments, metal pigments and the like can be mentioned.

Examples of resins include acrylic resins, fluorine-containing vinyl resins, cellulose resins such as nitrocellulose or cellulose acetate butyrate, vinyl chloride / vinyl acetate copolymer resins, petroleum resins, ketone resins, and oil-free resins. Alkyd resin, alkyd resin, epoxy resin and the like can be mentioned.

The resin obtained by the method of the present invention is PC
M can be used for forming a colored coating film or clear coating film, or for general building materials, building exteriors,
It can also be used as various coating agents for slate, tile, metal, plastic, automobile repair or automobile topcoat.

As the coating method, a conventionally used method such as air spray, airless spray, electrostatic spray, shower coating, dip coating, brush printing or roll coating can be used as it is.

As the curing conditions, curing agents such as those described above are appropriately selected, from room temperature drying and forced drying, to low-temperature baking at 100 to 150 ° C. for 20 to 30 minutes, and 200 to 230 ° C. 30 to 20
A wide variety of conditions can be adopted up to a high-temperature short-time baking of 0 seconds.

[0047]

Next, the present invention will be described more specifically with reference to examples, comparative examples, applied examples, and comparative applied examples. In the following, "%" means "% by weight" unless otherwise specified.

Examples 1 to 4 1 fully substituted with nitrogen
In a 1 liter stainless steel autoclave, a monomer other than the fluorine-containing vinyl monomer as shown in Table 1, a solvent, and a ratio of 2% based on the total amount of monomers as a polymerization initiator Of tert-butyl peroxypivalate and 0.5% of tert-butyl peroxy-2-ethylhexanoate.

Next, in Examples 1 to 3, bis (1,2,2,6,6-pentamethyl) was added as an anti-gelling agent at the time of polymerization to a ratio of 1% based on the total amount of the monomers. -4-piperidinyl) sebacate was also charged.

Thereafter, the liquefied and collected fluorinated vinyl monomer was injected under pressure, kept at 60 ° C. for 15 hours while stirring to carry out a polymerization reaction, and a solution of the desired fluorinated copolymer (A) -1) to (A-4) were obtained.

Comparative Examples 1-4 The same procedure as in Examples 1-4 except that the use of the monomer (b) was omitted, a control fluorine-containing copolymer solution (A'-
1) to (A′-4) were obtained.

[0052]

[Table 1]

[0053]

[Table 2]

Table 1 shows the obtained fluorinated copolymer solutions (A-1) to (A-4) and (A'-1) to (A ').
The weight average molecular weight for -4) is also shown.
As is clear from this table, at least 2
It is known that by copolymerizing the monomer (b) having two polymerizable unsaturated groups, the molecular weight is significantly increased.

Application Examples 1 to 3 and Comparative Application Examples 1 to
3 Fluorine-containing copolymer solutions (A-1), (A-2), (A-4),
(A'-1), (A'-2) and (A'-4) are first converted to (A-1), (A-2), (A'-1) and (A'-2). Is mixed with a curing agent and applied in the form of a resin composition, while (A-4) and (A'-4) are applied as they are, and each is applied in the form of about 25%.
A coating film having a thickness of micron (μm) was formed.

Next, these various coated plates were subjected to a bending test to compare and examine the flexibility of each coating film. The results are summarized in Table 2.

[0057]

[Table 3]

As can be seen from this table, a fluorine-containing copolymer solution having an increased weight-average molecular weight obtained by copolymerizing a monomer (b) having at least two polymerizable unsaturated groups in one molecule. (A-1), (A-2) and (A-4)
In any case, it is clearly recognized that the use of the monomer (b) is particularly excellent in flexibility as compared with the case where the monomer (b) is completely absent.

[0059]

The fluorinated copolymer obtained by the method of the present invention has a high molecular weight and can be used as it is or, if necessary, in a form mixed with a curing agent. By coating on a material or an undercoat film, it is possible to form a tough and flexible film excellent in flexibility that can respond to physical changes such as bending. In addition, the internal base material and the undercoat film can be protected from light deterioration for a very long time.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI C09D 135/02 C09D 135/02 (56) References JP-A-4-270748 (JP, A) JP-A-3-33148 (JP (A) JP-A-2-300180 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 127/12-127/20 C08F 214/18-214/28 C08F 216/12 -216/20 C08F 222/26-222/28 C09D 129/10 C09D 135/02

Claims (6)

(57) [Claims] 1. A fluorine-containing vinyl monomer in an organic solvent.
(A), a monomer (b) having at least two ethylenically unsaturated double bonds in a molecule, the monomer (a) and the monomer (a).
Overcoat with a coating containing a fluorocopolymer obtained by copolymerizing monomer (b) with another copolymerizable monomer (c)
Excellent flexible coating characterized by being used as a coating
Method of forming a film . 2. A fluorine-containing copolymer is a 15 to 70% by weight of the fluorine-containing vinyl monomer (a), and 30 to 85 wt% of other copolymerizable monomer (c), the Monomer (a), simple substance
For 1000 g of a mixture of the compound (b) and the monomer (c)
And at least 0.004 to 2 equivalents of the molecule
Monomer (b) having two ethylenically unsaturated double bonds
The compound according to claim 1, which is obtained by copolymerizing
A method for forming a coating film . 3. The method according to claim 1, wherein the fluorine-containing vinyl monomer (a) is
The method for forming a coating film according to claim 1 or 2, wherein the method is at least one compound selected from the group consisting of hexafluoropropylene, chlorotrifluoroethylene, tetrafluoroethylene, and vinylidene fluoride. 4. The method according to claim 1, wherein the monomer (b) having at least two ethylenically unsaturated double bonds in the molecule is an alkyl diol divinyl ether or an alkyl dicarboxylic acid divinyl ester . Any one
A method for forming a coating film . 5. The other copolymerizable monomers mentioned above is method of forming a coating film according to any one of claims 1-4 a hydroxyl group-containing vinyl monomer. 6. The method according to claim 5, wherein the proportion of the hydroxyl group-containing vinyl monomer is 2 to 100% by weight based on the other copolymerizable monomer (c).