JPH0718215A - Fluorinated coating composition - Google Patents

Abstract

PURPOSE:To obtain the composition improved in solvent resistance and blocking resistance by mixing a vinylidene fluoride resin, a silylated and/or isocyanato- containing methacrylate copolymer, and a curing catalyst. CONSTITUTION:100 pts.wt. resin component consisting of 30-90 pts.wt. vinylidene fluoride resin (A) (e.g. a vinylidene fluoridetetrafluoroethylene/ hexafluoropropylene terpolymer) and 10-70 pts.wt. polymer (B) obtained by copolymerizing a monomer mixture containing 0.001-15wt.% isocyanato- containing monomer (e.g. isocyanatoethyl methacrylate), 0-10wt.% monomer containing a hydrolyzable silyl group (e.g. vinyltrimethoxysilane) and 70-9wt.% methacrylic ester is mixed with 0.01-20 pts.wt. curing catalyst (C) (e.g. dibutyltin diacetate). To produce the composition, component A and component B are mixed by heating, and component C is then added to the mixture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinylidene fluoride-based paint which is cured at a low temperature and has excellent solvent resistance. More specifically, the present invention provides a coating composition in which the cross-linking site after the cross-linking reaction has excellent compatibility with the vinylidene fluoride resin and is sufficiently cured even at low temperatures to improve the blocking resistance.

[0002]

2. Description of the Related Art Vinylidene fluoride-based paints are known as conventional dry paints. The paint has physical properties excellent in weather resistance and stain removability of the coating film, but has a drawback of poor solvent resistance. In the case of cross-linking the paint, a method of introducing an OH group into an acrylic resin and cross-linking it with urethane cross-linking and melamine cross-linking can be considered. In these cross-linking methods, the cross-linking site after the cross-linking reaction is vinylidene fluoride-based. Since the compatibility with the resin is poor, there is a drawback that the coating film becomes cloudy as the crosslinking reaction proceeds. To compensate for these drawbacks, a hydrolyzable silyl group can be crosslinked as a functional group, and if a silyl group is used as a crosslinking group, the compatibility is excellent and the transparency of the coating film is maintained. However, although this cross-linking system is excellent in weather resistance and stain resistance as a coating that is dried at room temperature, it has a problem in that it has insufficient curability and poor blocking resistance in factory line coating applications.

[0003]

DISCLOSURE OF THE INVENTION As a result of intensive studies, we have found that when cross-linked with an urea group using an isocyanate group, the compatibility is excellent, and the reaction rate is sufficiently fast, so that it is also excellent in blocking resistance. I found a thing.

[0004]

The present invention comprises (A) 30 to 90 parts by weight of vinylidene fluoride resin, and (B) 0.001 to 15% by weight of a monomer containing an isocyanate group.
Resin component 100 consisting of 10 to 70 parts by weight of a polymer obtained by copolymerizing 0 to 10% by weight of a monomer containing a hydrolyzable silyl group and a monomer containing 70 to 99% by weight of a methacrylic acid ester. The present invention provides a fluorine coating composition comprising 0.01 to 20 parts by weight of a curing catalyst (C) with respect to parts by weight.

The vinylidene fluoride resin (A) used in the present invention is, for example, a homopolymer of vinylidene fluoride or vinylidene fluoride and vinyl fluoride, trifluoroethylene, tetrafluoroethylene, bromotrifluoroethylene, chlorotrifluoro. A copolymer obtained by copolymerizing ethylene, pentafluoropropylene, hexafluoropropylene, and at least one fluoroolefin monomer selected from the group consisting of perfluoroalkyl, trifluoroalkyl and trifluorovinyl ether. is there. Particularly preferably, it is a terpolymer of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene, and the amount of vinylidene fluoride used is preferably 10 to 99% by weight in terms of monomer ratio.
More preferably, it is 60 to 90% by weight, tetrafluoroethylene is 50 to 20% by weight, and hexafluoropropylene is 20 to 1% by weight.

The component (B) of the present invention comprises 0.001 to 15% by weight of a monomer containing an isocyanate group, 0 to 10% by weight of a monomer containing a hydrolyzable silyl group, and 70 to 99% by weight of a methacrylic acid ester. It is obtained by copolymerizing a monomer containing 10%. Examples of the monomer containing an isocyanate group that can be used in the present invention include isocyanate ethyl acrylate, isocyanate ethyl methacrylate, isocyanate propyl acrylate, isocyanate propyl methacrylate, and derivatives thereof, m-isopropenyl-α, α-dimethylbenzenediisocyanate. However, isocyanatoethylmethacrylate is preferred.

The hydrolyzable silyl group of the monomer containing the hydrolyzable silyl group used in the present invention has the general formula (X represents a hydrolyzable group or element, R ₁ represents hydrogen or an alkyl group having 1 to 10 carbon atoms, an aryl group or an aralkyl group, and n is an integer of 1 to 3).
Hydrolyzable groups include halogen elements, alkoxy groups, acyloxy groups, ketoximate groups, amide groups, acid amide groups, aminooxy groups, mercapto groups, alkenyloxy groups, but they are easy to handle as paints, reaction speed, and odor. It is preferable to use an alkoxyl group because it does not generate a corrosive substance. The number of carbon atoms of the alkoxyl group is 1 to 1.
The number is preferably 0, more preferably 1 to 5, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, a buxy group, and a pentoxy group. It is preferable to use these, because practically, the adhesiveness to an inorganic material or the like can be quickly obtained.

Examples of the monomer containing a hydrolyzable silyl group which can be used in the present invention include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane,
Vinylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) silane, allyltrimethoxysilane,
Trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, methyldimethoxysilylethyl vinyl ether, triethoxysilylpropyl vinyl ether, methyldimethoxysilylpropyl vinyl ether, γ- (meth) acroyloxypropyltrimethoxysilane, γ- (meth) acroyl Examples thereof include oxypropyltriethoxysilane, γ- (meth) acroyloxypropylmethyldimethoxysilane, and the like. Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and the like.

In the present invention, the proportion of the monomer containing isocyanate is 0.001 to 15% by weight, preferably 0.1 to 10% by weight, based on the total monomers, and the proportion is 0.001. If it is less than 15% by weight, the crosslinking of the resulting coating composition when cured will be insufficient and boiling resistance and solvent resistance will be poor. If it exceeds 15% by weight, the stability of the coating composition will be poor. . The proportion of the monomer containing a hydrolyzable silyl group is 0 to 10% by weight, preferably 0.1 to 8% by weight, based on the total monomers, and the proportion is 10% by weight.
When it exceeds, storage stability and pigment dispersibility are significantly impaired. The proportion of methacrylic acid ester used is usually 70 to 99% by weight, preferably 75 to 99% by weight, and particularly preferably 80 to 99% by weight, based on the total monomers. (B) of the present invention
The number average molecular weight of the component copolymer is usually 1,000.
100,000, preferably 4,000 to 20,000
It is 0.

In the present invention, in addition to the above, a monomer which is copolymerized with the methacrylic acid ester is a total monomer.
9% by weight or less can be copolymerized, and examples thereof include acrylic acid esters such as methyl acrylate, butyl acrylate and 2-ethylhexyl acrylate, carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid and fumaric acid, and maleic anhydride. Anhydrides such as acids, epoxy compounds such as glycidyl acrylate, amino compounds such as diethylaminoethyl acrylate, diethylaminoethyl methacrylate, aminoethyl vinyl ether, acrylamide, methacrylamide, itaconic acid diazide,
Amide compounds such as α-butyl acrylamide, crotonamide, fumaric acid diazide, maleic acid diazide, N-butoxymethyl acrylamide, N-butoxyethyl acrylamide, acrylonitrile, iminol methacrylate, styrene, α-methylstyrene, vinyl chloride, vinyl acetate , Vinyl propionate and the like.

The curing catalyst (C) used in the present invention is not particularly limited as long as it accelerates the crosslinking reaction of isocyanate. Specifically, basic compounds such as butylamine, dibutylamine, hexylamine, t-butylamine, ethylenediamine, isophoronediamine, imidazole, lithium hydroxide, potassium hydroxide, sodium methylate, tetraisopropyl titanate, tetrabutyl titanate, octyl. Tin acid, lead octylate, cobalt octylate, zinc octylate, calcium octylate, lead naphthenate, cobalt naphthenate, dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, dibutyltin malate, monooctyltin trismercapto, etc. Metal-containing compounds, p-toluenesulfonic acid, trichloroacetic acid, phosphoric acid, monoalkylphosphoric acid, dialkylphosphoric acid, phosphoric acid ester of β-hydroxyethyl acrylate, monoalkylphosphorous acid, dialkyl Mention may be made of an acidic compound such as alkyl phosphite. As a curing catalyst,
One of the above curing catalysts or a combination of two or more thereof may be used. When a hydrolyzable silyl group is used in combination with the methacrylate polymer, a curing catalyst having a catalytic action on both the isocyanate and the hydrolyzable silyl group is preferable, for example, dibutyltin diacetate, dibutyltin dioctate, It is preferable to use a tin compound such as dibutyltin dilaurate, dibutyltin malate or monooctyltin trismercapto.

The ratio of the above components (A) to (C) in the present invention is 30 to 90 parts by weight, preferably 50.
To 80 parts by weight, 10 to 70 parts by weight of the component (B), preferably 0.01 to 20 parts by weight of the component (C), preferably 0.1 to 100 parts by weight of the resin component consisting of 20 to 50 parts by weight. ~ 15 parts by weight. Here, the ratio of the component (A) is 30 in the total 100 parts by weight of the component (A) + the component (B).
If it is less than 100 parts by weight, the weather resistance is poor, and if it exceeds 90 parts by weight, crosslinking and curing cannot be obtained. Further, the component (C) is the component (A) +
When the amount is less than 0.01 parts by weight based on 100 parts by weight of the total of the component (B), the catalytic effect is weak, and when it exceeds 20 parts by weight, the coating film becomes cloudy, which is not preferable.

The fluorine coating composition of the present invention is usually used as a varnish dissolved in a solvent. The amount of the solvent in the present invention is preferably 5 to 95% by weight, more preferably 50 to 20% by weight, and particularly preferably 30 to 40% by weight based on the varnish. The solvent that can be used in the present invention is an aliphatic or alicyclic ketone-based, ester-based, or ether-based organic solvent. Among these, it is preferable to include an organic solvent having a boiling point of 100 ° C. or more in order to form a smooth coating film. For example, as the ketone-based compound, methyl n-probe ketone, diethyl ketone, methyl isobutyl ketone, methyl n -Butyl ketone, ethyl n-butyl ketone, methyl n-amyl ketone, diisobutyl ketone, methyl n-hexyl ketone, methyl oxide, cyclohexanone, diacetone alcohol, methylphenol ketone, isophorone; as the ester system, n-propyl acetate, acetic acid n- Butyl, isobutyl acetate,
2-methoxyethyl acetate, amyl acetate, dimethyl adipate, dimethyl glutarate, dimethyl succinate; as ether type, methyl cellosolve, 2-methoxy-2-propanol cellosolve, 1-ethoxy-
Examples include propylene glycol monomethyl ether acetate such as 2-propanol butyro cellosolve and 1,4-dioxane.

In the present invention, it is preferable to use the dehydrating agent (D) because the storage stability is improved. The dehydrating agent (D) used in the present invention is an ester type dehydrating agent having a high hydrolysis rate, Specifically, trimethyl orthoformate,
Trialkyl orthoformates such as triethyl orthoformate, tripropyl orthoformate, and tributyl orthoformate,
Trialkyl orthoacetates such as trimethyl orthoacetate, triethyl orthoacetate, tripropyl orthoacetate and tributyl orthoacetate, and tetramethyl orthosilicate,
Tetraethyl orthosilicate, tetrapropyl orthosilicate,
Tetraalkyl orthosilicates such as tetrabutyl orthosilicate are used. Further, after partially hydrolyzing tetraalkyl orthosilicate, an oligomer of orthosilica tetraalkyl dehydrated and condensed, or an alkoxide of silicon element such as methyltrimethoxysilane, ethyltrimethoxysilane, methyltriethoxysilane, and ethyltriethoxysilane,
Also, partially hydrolyzed components and dehydrated condensates thereof can be used. The addition amount of the dehydrating agent in the present invention is
It is usually 0.1 to 15 parts by weight based on 100 parts by weight of the total of the components (A) and (B). In the present invention, the mixing order of the components (A), (B) and (C) is not limited, but it is preferable to add the component (C) after mixing the components (A) and (B). Further, when the component (D) is added, it is preferable to add it before the pigment dispersion and after the pigment dispersion. The coating composition of the present invention can be widely used for buildings, bridges, structures such as tanks, aluminium, precoat such as zinc steel plate, postcoat applications, kiln-solidifying siding boards, roof tile line coating applications, etc. it can.

[0015]

EXAMPLES Next, examples and comparative examples of the present invention will be shown.
The present invention will be described in more detail. Example 1 Vinylidene fluoride resin (A) (vinylidene fluoride 53
Wt%, copolymer of 38 wt% tetrafluoroethylene and 9 wt% hexafluoroethylene) 60 parts, 2.7 wt% of isocyanate ethyl acrylate, 85.5 wt% of methyl methacrylate, 1 butyl acrylate.
A methacrylate-based polymer (B) obtained by copolymerizing a monomer mixture of 1.8% by weight in toluene (concentration 40
%, Mn 10,000), and 0.86 parts of methyl orthoacetate as a dehydrating agent (D) were added to a mixed solvent consisting of 41 parts of butyl acetate, 6.8 parts of methyl isobutyl ketone and 58 parts of propylene glycol methyl ether acetate, The mixture was heated and stirred at 80 ° C. for 1 hour and dissolved to obtain a solution composition. Titanium oxide (“Taipei 7R-830” manufactured by Ishihara Sangyo Co., Ltd.) was used as a pigment in the obtained solution composition 5
7 parts were added and dispersed by a ball mill to obtain a white coating composition. To the above mixture, 2.0 parts of monooctyltin trismercapto was added and mixed as a curing catalyst (C), and this was coated on an aluminum plate so that the film thickness after drying was 30 μm, and predried for 20 minutes. After making it 100 ℃, 2
It was baked and dried for 0 minutes. For the coating film after baking,
The following evaluation was performed.

1) Boiling resistance test It was immersed in boiling water for 2 hours and visually evaluated for any abnormalities in the coating film. No abnormality; ○ White turbidity of coating film; × 2) Solvent resistance test Toluene was included in a paper towel and the coating film surface was 100%.
Rubbed twice. The coating film on the rubbing portion was visually evaluated for any abnormality. No abnormality; ○ Decrease in gloss of the coating film; × 3) Work gloves pressure resistance test (blocking resistance) Immediately after heating and drying at 100 ° C for 20 minutes, the sample plate was transferred to a hot air dryer set at 80 ° C, and the sample plate When the temperature of the clip-type surface thermometer attached to the surface reached 80 ° C., the work gloves were pressed against the sample plate with a pressure of about 1 kgf / cm ² , and it was visually evaluated whether or not a mark was left on the sample plate surface. No abnormality; ○ Traces remain; × 4) Adhesion test 10 squares of 1 mm square on the sample plate with a cutter knife
0 pieces were made, a cellophane tape was pressure-bonded on the piece, and then peeled off, and the number of 100 pieces left was evaluated. 5) Accelerated weather resistance test Accelerated weather resistance test was conducted according to JIS K5400 9.8.1 Sunshine Bon Arc lamp system, and exposure was 2,000.
The gloss retention at 0 hours was calculated. Gloss retention rate 80% or more; ○ less than 80%; × 6) Storage stability test The above coating composition was placed in a glass bottle with a lid and stored at 25 ° C, and the viscosity increase rate after 3 months was determined. Thickening rate less than 50%; ◯ 50% or more; × The results are shown in Table 1. 1) Boil resistance test, 2) Solvent resistance test, 3) Work pressure bonding test, 5) Accelerated weathering test, and 6) Storage stability test were good, but 4) Adhesion with aluminum plate It was a little inferior.

Example 2 Of the solution-like composition of Example 1, the composition of the methacrylate polymer (B) was 83.4% by weight of methyl methacrylate, 11.6% by weight of butyl acrylate and 2.7% by weight of isocyanate ethyl acrylate. %, Γ-methacryloxypropyltrimethoxysilane was changed to 2.3% by weight, and a coating composition was prepared in the same manner as in Example 1, added with a curing catalyst, baked and dried, and evaluated. 1) Boil resistance test,
The 2) solvent resistance test, 3) work gloves pressure bonding test, 4) adhesion test, 5) accelerated weathering test, and 6) storage stability test were all good.

Example 3 A coating composition was prepared in the same manner as in Example 1 and monooctyltin trislaurate (2.0) was used as a curing catalyst (C).
Part was added, and thereafter the same evaluation as in Example 1 was performed. 1) Boiling resistance test, 2) Solvent resistance test, 3) Work pressure bonding test, 5)
The accelerated weather resistance test and 6) storage stability test were excellent, but they were slightly inferior to 4) adhesion test.

Comparative Example 1 Of the solution-form composition of Example 1, the composition of the methacrylate copolymer (B) was 83.8% by weight of methyl methacrylate and 11.5% by weight of butyl acrylate without using isocyanate ethyl acrylate. %, Γ-methacryloxypropyltrimethoxysilane was changed to 4.7% by weight, and a coating composition was prepared in the same manner as in Example 1 using the same methacrylate-based copolymer as in Example 1 to prepare a curing catalyst. Was added, baked and dried, and evaluated. 1) Boil resistance test,
Excellent in 4) adhesion test, 5) accelerated weathering test, and 6) storage stability test, but inferior to 2) solvent resistance test and 3) workman pressure bonding test.

Comparative Example 2 The coating composition of Example 1 was evaluated by baking and drying without adding a curing catalyst. Although 1) boiling resistance test, 5) accelerated weathering test, and 6) storage stability test are good, they are inferior to 2) solvent resistance test, 3) workman pressure bonding test, and 4) adhesion test.

Comparative Example 3 [0021] Of the solution composition of Example 1, except that the composition of the methacrylate copolymer (B) was changed to 87.5% by weight of methyl methacrylate and 12.5% by weight of butyl acrylate. A coating composition was prepared in the same manner as in Example 1, a curing catalyst was added, and the composition was baked and dried and evaluated. 5) Accelerated weather resistance test and 6) Storage stability test were good, but 1) Boil resistance test, 2) Solvent resistance test, 3) Work pressure bonding test, and 4) Adhesion test were bad Met.

Comparative Example 4 As a vinylidene fluoride resin (A), "KYNAR A
DS ", 28 parts, and 180 parts of the methacrylate copolymer (B) (40% toluene solution) having the same composition as in Example 1.
Parts, 1.5 parts of methyl orthoacetate as a dehydrating agent (D), 27 parts of methyl isobutyl ketone, propylene glycol,
It was added to a mixed solvent consisting of 51 parts of methyl ether acetate, and heated and stirred at 80 ° C. for 1 hour to be dissolved to obtain a solution composition. A coating composition was prepared in the same manner as in Example 1, and 3.6 parts of monooctyltin trismercapto was added as a curing catalyst (C), baked and dried, and evaluated. 1)
Excellent in boiling resistance test, 2) solvent resistance test, 3) work gloves pressure bonding test, and 6) storage stability test, but poor in 4) adhesion test and 5) accelerated weathering test .

Comparative Example 5 As a vinylidene fluoride resin (A), "KYNAR A
DS ", 93 parts, and the methacrylate copolymer (B) (40% toluene solution) having the same composition as in Example 1 17.
5 parts, 0.14 parts of methyl orthoacetate as a dehydrating agent (D), 40.6 parts of butyl acetate, and 7 parts of methyl isobutyl ketone.
It was added to a mixed solvent consisting of 6.4 parts and 58 parts of propylene glycol, and heated and stirred at 80 ° C. for 1 hour to be dissolved to obtain a solution composition. A coating composition was prepared in the same manner as in Example 1, 0.35 part of monooctyltin trismercapto was added as a curing catalyst (C), and the mixture was baked and evaluated. 5) Accelerated weathering resistance test and 6) Storage stability test were good, but 1) Boil resistance test, 2) Solvent resistance test, 3) Work pressure bonding test, and 4) Adhesion test were bad Met.

Comparative Example 6 Of the solution composition of Example 1, the composition of the methacrylate copolymer (B) was 75.5% by weight of methyl methacrylate, 7.0% by weight of butyl acrylate, 17.5% by weight of isocyanate ethyl acrylate. Except changed to%
A coating composition was prepared in the same manner as in Example 1, a curing catalyst was added, and the composition was baked and dried for evaluation. 1) Boiling resistance test, 2) Solvent resistance test, 3) Work gloves pressure bonding test, and 5) Accelerated weathering test were good, but 4) Adhesion test, and 6)
The storage stability test was poor even with the addition of a dehydrating agent.

Comparative Example 7 Of the solution composition of Example 1, the composition of the methacrylate copolymer (B) was 75.5% by weight of methyl methacrylate, 7.0% by weight of butyl acrylate, and 2.5% by weight of isocyanate ethyl acrylate. % And γ-methacryloxypropyltrimethoxysilane were changed to 15.3% by weight, the same evaluation as in Example 1 was carried out, but the dispersibility of the pigment was poor.

[0026]

[Table 1]

[0027]

EFFECT OF THE INVENTION The fluorine coating composition of the present invention is excellent in boiling resistance, solvent resistance, weather resistance and storage stability, and has sufficient curability, so that it is excellent in blocking resistance. In particular, the conventional fluorine coating composition has insufficient curability and poor blocking resistance, so that it was a problem in factory line coating, but the problem was solved.

Claims (1)

[Claims] 1. A vinylidene fluoride resin (A) 30 to 9
0 parts by weight, and (B) 0.001 to 15% by weight of a monomer containing an isocyanate group, 0 to 10% by weight of a monomer containing a hydrolyzable silyl group, and methacrylic acid ester 7
0.01 to 20 parts by weight of a curing catalyst (C) is contained with respect to 100 parts by weight of a resin component consisting of 10 to 70 parts by weight of a polymer obtained by copolymerizing a monomer containing 0 to 99% by weight. A fluorine coating composition comprising: