JPH03220272A - Organic solvent-based fluororesin coating composition - Google Patents

Abstract

PURPOSE:To prepare a one-component coating compsn. which is curable at room temp. and improved in weatherability, durability based on coating film strength, stain resistance of coating film, chemical stability, surface flatness, etc., by dissolving a specific fluororesin and a specific acrylic resin in a solvent. CONSTITUTION:40-70wt.% vinylidene fluoride, 20-50wt.% tetrafluoroethylene, and 1-30wt.% hexafluoropropylene are copolymerized to give a fluororesin having a number-average mol.wt. (Mn) of 40000-150000, a ratio the wt.-average mol.wt. (Mw) to the Mn of 5 or lower, and an m.p. of 70-150 deg.C. Independently, 90wt.% or higher methyl methacrylate, if necessary with another alkyl (meth) acrylate, is polymerized to give an acrylic resin having an Mn of 2000-50000, a ratio of Mw/Mn of 1.1-4, an acid value of 0.1-64mgKOH/g, and an isotactic bond content of 10% or lower. 50-90wt.% fluororesin and 50-10wt.% acrylic resin are dissolved in an org. solvent boiling at 100 deg.C or higher.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coating composition, and more specifically, the present invention relates to a coating composition, and in particular, it has excellent weather resistance, durability derived from coating film strength, stain resistance, chemical stability, and surface smoothness. The present invention relates to an organic solvent-based fluorine-containing paint composition that forms a coating film that has extremely excellent properties such as, and also has excellent adhesion to a substrate.

[Prior Art] Polyvinylidene fluoride is used as a coating material because of its excellent properties such as weather resistance, stain resistance, and corrosion resistance.

Widely used as lining material and molding material.

However, conventional polyvinylidene fluoride paints
Generally, it is dispersed in a high boiling point solvent, and in the coating process, it is necessary to bake the coating under heating at 200° C. or higher. Therefore, such paints cannot be used for room-temperature painting at construction sites, etc., and require line painting, which limits the scope of their use. Furthermore, heating at 200° C. or higher during coating has a large effect on the coating substrate, and for example, there are problems such as deformation of substrates such as aluminum building materials.

Therefore, a method of dissolving a soluble vinylidene fluoride-based polymer in a solvent to form a solution composition and applying this is considered, but the mechanical strength of the coating film is inferior when using vinylidene fluoride-based polymer alone. Therefore, coating compositions containing acrylic polymers are generally known.

For example, in Japanese Patent Publication No. 62-14574, acrylic polymers mainly composed of fluororubber such as vinylidene fluoride/hexafluoropropylene or copolymers of vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene and methyl methacrylate are disclosed. A coating composition is disclosed in which the compound is dissolved in a lower ketone.

However, compositions made of a combination of these fluororubbers and acrylic polymers do not have sufficient solubility in solvents and sufficient compatibility between the polymers, resulting in poor weather resistance and durability. It is enough.

On the other hand, as a composition using a fluororesin, one in which a binary copolymer of vinylidene fluoride and tetrafluoroethylene and an acrylic polymer are similarly dissolved in ketones is known. As in the case of the composition, it did not have sufficient solubility in the solvent and sufficient compatibility between the polymers, resulting in insufficient weather resistance and durability. Therefore, these conventional compositions have not been able to be practically used as top coating compositions that can be dried at room temperature.

[Problems to be Solved by the Invention] The present inventors have conducted extensive studies on the molecular weight and molecular weight distribution of vinylidene fluoride polymers (fluororesins) and acrylic polymers, and have found that We have found a coating composition that has good compatibility and solubility in solvents, and has a sufficiently homogeneous coating composition after drying.

The purpose of the present invention is to develop durability derived from weather resistance and coating strength without impairing the inherent properties of fluororesins.

An organic solvent that can form a coating film with outstanding properties such as stain resistance, chemical stability, and surface smoothness, as well as excellent adhesion to the substrate, and can be corrugated and dry at room temperature. An object of the present invention is to provide a composition for a fluorine-containing paint.

[Means for Solving the Problems] The present invention uses vinylidene fluoride 40-40 as a monomer component.
70% by weight, tetrafluoroethylene 20-50% by weight
and 1 to 30% by weight of hexafluoropropylene, number average molecular weight Mn is 40,000 to 150,000, and weight average molecular weight M
Fluororesin 50-90 having a ratio Mw/Mn of w to number average molecular weight Mn of 5 or less and a melting point of 70-150°C
% by weight, contains 90% by weight or more of methyl methacrylate as a monomer component, Mn is 2,000 to 50,000, M w /M
The present invention relates to an organic solvent-based fluorine-containing paint composition containing 50 to 10% by weight of an acrylic resin in which n is 1.1 to 4 in a solution state.

The present invention will be explained in detail below.

In the present invention, the proportion of the fluororesin to the whole resin is 50 to 90% by weight, preferably 55 to 70% by weight, and the proportion of the acrylic resin to the whole resin is 50 to 10% by weight, preferably 45 to 30% by weight. be.

If the proportion of fluororesin is less than 50% by weight, the weather resistance and stain resistance of the coating film will be impaired, and if it is greater than 90% by weight, there will be a decrease in the adhesion and strength of the coating film, which is preferable. do not have.

Further, in the present invention, the proportion of vinylidene fluoride as a monomer component of the fluororesin is 40 to 70% by weight, preferably 45 to 60% by weight.

When the proportion of vinylidene fluoride is more than 70% by weight, the solubility in organic solvents decreases, while when it is less than 40% by weight, the compatibility with the acrylic resin decreases, resulting in In either case, the coating film composition becomes non-uniform and weather resistance and stain resistance are impaired, which is not preferable.

The proportion of tetrafluoroethylene based on the monomer components is 20 to 50% by weight, preferably 30 to 50% by weight. When this proportion is 30 to 50% by weight, the stain resistance of the coating film is improved. If the proportion of tetrafluoroethylene exceeds 50% by weight, the compatibility with the acrylic resin will decrease, and if it is less than 20% by weight, the weather resistance and stain resistance of the coating film will decrease, so either case is not preferred.

Further, the proportion of hexafluoropropylene to the monomer components is 1 to 30% by weight, preferably 5 to 20% by weight.
It is. If the proportion of hexafluoropropylene is less than 1% by weight, the flexibility of the coating film will be impaired, while if it is greater than 30% by weight, the coating film will be too soft due to rubbery properties, resulting in poor durability and stain resistance. Not only is it inferior in gender, but
Compatibility with the acrylic resin is also insufficient, resulting in decreased durability, which is unfavorable for coating compositions in either case. In particular, when hexafluoropropylene exceeds 40% by weight, the polymerization rate during polymerization of the fluororesin becomes extremely slow, making it industrially impractical.

In the present invention, the fluororesin has a melting point (Tm) of 70 to 150'C as measured by differential thermal analysis. If the Tm of the fluororesin is lower than 70"C, the compatibility with the acrylic resin is poor;
If the temperature is higher than 0.degree. C., the solubility in solvents and the compatibility with the acrylic resin will decrease, making it impossible to obtain sufficient weather resistance.

The number average molecular weight Mn of the fluororesin is 40,000 to 150,000 in terms of styrene by gel permencon chromatography method.
Preferably it is 40,000 to 90,000.

When Mn is less than 40,000, the strength, weather resistance,
Stain resistance is significantly reduced, and conversely, if the molecular weight is greater than 150,000, the compatibility with acrylic resin and solubility in solvents decreases, and as a result, it becomes difficult to obtain sufficient weather resistance and stain resistance. unfavorable to Furthermore, commercially available fluororubbers generally have an Mn of 200,000 or more, so they are not suitable for use as coating compositions.

Ratio M between weight average molecular weight fi M w and number average molecular weight Mn
w/Mn is 5 or less, more preferably in the range of 1.5 to 3.

When the value of M w / M n is greater than 5, the proportion of high molecular weight components in the polymer increases, resulting in a significant increase in the viscosity of the paint, a decrease in compatibility between resins, and an increase in the amount of low molecular weight components. This results in a decrease in the weather resistance of the coating film, making it undesirable as a coating composition.

In the present invention, the number average molecular weight Mn of the acrylic resin is
2,000 to 50,000, preferably 3,000 to 20,000, more preferably 3,000 to 15,000. By using an acrylic resin with a molecular weight of 3,000 to 15,000, the stain resistance and hardness of the coating film are improved. Furthermore, if Mn is less than 3,000, weather resistance is impaired, and if Mn is greater than 50,000, compatibility and solubility are reduced, which is not preferable.

The ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn in the acrylic resin is 1.1 to 4, preferably 2 to 3. M w / M (If the value of 1 is smaller than 1.1, the adhesion of the coating will be poor, and if M w / M n is larger than 4, the low molecular weight components will be relatively large. This is not preferable because weather resistance is impaired.

These acrylic resins are particularly suitable for glass transition temperature T
Methyl methacrylate-based polymers having g of 80° C. or higher are preferable in terms of compatibility and film strength, and can improve the weather resistance and durability of the coating composition.

In the present invention, the seven polymers used in the acrylic resin include methyl, ethyl, propyl, butyl, isobutyl, n-hexyl, acrylic acid or methacrylic acid,
Esters such as 2-ethylhexyl, lauryl or stearyl may be mentioned. Among these, methyl methacrylate is an essential component and needs to be used in a proportion of 90% by weight or more as a monomer component of the acrylic resin. If the proportion of methyl methacrylate is less than 90% by weight, the coating film will have insufficient weather resistance, mutual compatibility with resins, and chemical resistance.

In addition, other alkyl (meth)acrylate monomers include methyl acrylate, ethyl alkrylate,
Butyl acrylate, methyl methacrylate, butyl methacrylate, isobutyl methacrylate, etc. can be preferably used.

Furthermore, acrylic acid,
Preferably, acid monomers such as methacrylic acid, fumaric acid, itaconic acid are added.

The acrylic resin preferably has an acid value of 0.1 to 64 mg KOH/g, more preferably 2 to 25 mg KOH/g in terms of potassium hydroxide.

By setting the acid value within this range, the hardness of the coating film can be increased. The acid value of the acrylic resin can be set to a predetermined value by adjusting the addition ratio of acid monomers such as acrylic acid, metharylic acid, fumaric acid, and itaconic acid.

Further, in the acrylic resin, the isotactic steric bond component is preferably 10% by weight or less, more preferably 7% by weight or less.

If the isotactic steric bond component is in this range,
It has excellent compatibility with fluororesins and improves coating performance such as weather resistance and film-forming properties.

The stereoregularity of acrylic resin is determined from the literature “FA, B
Ovey, J. Blymer Sci, 4417
3 (1960) J., three α-
It can be determined from the signal area of the methyl group.

In the present invention, suitable organic solvents for dissolving the above-mentioned fluororesin and acrylic resin are aliphatic or alicyclic ketone type or ester type.

It is an ether-based organic solvent. Among these, the boiling point is 1
Containing an organic solvent at 00°C or higher is preferable in order to form a smooth coating film. For example, as a ketone type, methyl n-
Propyl ketone, diethyl ketone, methyl isobutyl ketone, methyl n-butyl ketone, ethyl n-butyl ketone, methyl n-amyl ketone, diisobutyl ketone, methyl n-hexyl ketone, mesityl oxide, cyclohexanone, diacetone alcohol, methylphenol ketone, isophorone; ester As systems, n-propyl acetate, n-butyl acetate, isobutyl acetate, 2-methoxyethyl acetate, amyl acetate, dimethyl adipate, dimethyl glutarate, dimethyl succinate; as ether systems, methyl cellosolve, 2-methoxy-
Examples include 2-propatol cellosolve, 1-ethoxy-2-propatol butyl cellosolve, 1,4-dioxane, propylene glycol methyl ether, propylene glycol methyl ether acetate.

[Examples] Next, Examples and Comparative Examples of the present invention will be shown to explain the present invention in further detail.

Example 1 Volume 5 with stirrer and external temperature regulating jacket
1 of deionized and deoxygenated water in 1 autoclave
kg, ammonium persulfate 2.4 g.

4.0 g of ammonium perfluorooctanoate and 0.8 g of sodium acid sulfite were charged, and 0.2 g of sodium hydroxide was further added.

After replacing the inside of the autoclave with nitrogen gas three times, 170 g of vinylidene fluoride (VdF), 80 g of tetrafluoroethylene (TFE), and 9 og of hexafluoropropylene (f(FP)) were charged, and the mixture was heated at 60°C for 7 hours with stirring. Polymerization was carried out over a period of time.

This reaction product was coagulated, the polymer was filtered, washed with water, and then with n-hexane, and further dried in a vacuum dryer to obtain 160 g of a white powdery fluororesin.

As a result of measurement by FNMH, the composition ratio (weight %) of this fluororesin was found to be VdF/TFE/HFP of 61/24/1.
It was 5. In addition, the number average molecular weight (M
n) is 50,000 in terms of polystyrene by gel permeation chromatography, and the weight average molecular weight (
The ratio (M w ) to the number average molecular weight (M n )
/Mn) was 1.9.

The melting point (Tm) of the obtained fluororesin was 90° C. as measured by differential thermal analysis using a DuPont Instruments Series 99 thermal analyzer according to STM 0341g. This is shown in Table 1.

Next, 198 g of methyl methacrylate (MMA), 10 g of 1 methyl methacrylate (EMA), 40 g of a 5% aqueous polymethacrylic acid solution, and 400 Fr of deionized and deoxidized water were placed in a 30 flask equipped with a thermometer and a condenser. Furthermore, NN'-azoisobutyronitrile 2
．． Added 5g.

This was heated in a water bath under a nitrogen stream until it boiled, and when the content reached 93°C, the polymerization operation was stopped, followed by filtration and washing with water.

This was dried in a vacuum dryer to obtain a white granular acrylic copolymer. Composition ratio (weight%) of this acrylic resin
has an MMA/EMA of 9515, a number average molecular weight (M n ) of 15.001 in terms of polystyrene determined by gel permeation chromatography, and a weight average molecular weight of 1 (
Mn> and number average molecular weight (M w ) ratio M w / M
n was 2.1.

Next, 70 g of the obtained fluororesin and 30 g of acrylic resin were added.
was dissolved in 185 g of a mixed organic solvent consisting of 50% by weight of cyclohexanone, 25% by weight of methyl isobutyl ketone and 25% by weight of n-butyl acetate at 65°C to obtain a solution composition.

To this solution composition, TiQ2 (manufactured by Ishihara Sangyo ■ [Tie Bake R-830J) was added as a pigment in an amount of 20% by volume based on the solid content, and the mixture was stirred with a ball mill.

Dispersion was performed to prepare a coating composition.

This coating composition was applied onto a steel plate using a doctor blade having a gap of 150 μm, dried at room temperature, and then cured for one week to obtain a coating film.

The following physical property tests were conducted on the obtained coating film.

(a) Adhesion Measured according to JIS K5400 using a cross-cut tape peeling method. The degree of adhesion is determined by the number of peeled coating pieces, with complete adhesion being 100/100, and completely peeling being 0/100.

(b) Durability: 60″ from the inside of the vinyl pipe to the painted surface from a height of 2m
A nut (M-6) was continuously dropped at an angle of , and the weight of the nut at the end where the base material was exposed was evaluated. Judgment was made using the following indicators.

5th grade 40kg or more (Good) 4th grade 30-39kg 3rd grade 26-29kg 2nd grade 21-25kg 1st grade 20kg or less (Poor)
The gloss retention rate (%) after 00 hours was measured using a gloss needle (rGM 28DJ, manufactured by Murakami Color Technology Research Co., Ltd.). The higher the gloss retention rate, the better.

Table 1 shows the results of physical property tests on these coatings.

Example 2 Fluororesin (VdF/
TFE/HFP-60/23/17゜M n = 80
．． 000. Mw/Mn-2,5,) 80 g
and an acrylic resin consisting only of methyl methacrylate (M n -18,000, M
w/Mn=2.5) 20 g was dissolved in an organic solvent in the same manner as in Example 1 to obtain a solution composition.

A coating film was formed from this composition in the same manner as in Example 1, and its physical properties were tested. The results are shown in Table 1.

Example 3 Fluororesin (VdF/
TFE/HFP-65/23/12°M n -80,
000, Mw/M n -2,4) 60 g and acrylic resin (MMA/EA-9515, Mn-13,00
0,Mn/Mw-2,0) 40 g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition.

A coating film was formed from this composition in the same manner as in Example 1, and its physical properties were tested. The results are shown in Table 1.

Example 4 60 g of the same fluororesin as in Example 1 and 40 g of the same acrylic resin as in Example 2 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and its physical properties were tested. The results are shown in Table 1.

Example 5 Fluororesin (VdF/
TFE/HFP-51/34/15゜Mn-55,00
0, Mw/Mn-1,9) 70 g, and acrylic resin (M MA / E MA = 95 / 5,
Mn-9,000, Mn/Mw=2.1)30
g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition.

A coating film was formed from this composition in the same manner as in Example 1, and its physical properties were tested. The physical property tests include (a) adhesion and (b) durability as described above.

In addition to (c) weather resistance, the following (d) stain resistance was also tested. The results are shown in Table 2.

(d) A paste-like mixture of stain-resistant carbon powder and glycerin in a weight ratio of 1:2 was uniformly applied to the surface of the coating film and left for 24 hours. Thereafter, this coating film was washed with water, and the degree of removal of dirt was visually observed and evaluated on the following three scales.

○: Dirt was completely removed.

Δ: Some stains remained.

×: Considerable dirt remained.

Example 6 Fluororesin (VdF/
TFE/HFP-42/48/10°Mn =80,0
00. Mw/Mn-2,5) 80 g and Example 1
An acrylic resin consisting only of methyl methacrylate (M n -11i, 000. M w /
20 g of Mn-2,5) was dissolved in an organic solvent in the same manner as in Example 1 to obtain a solution composition.

A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted.

The results are shown in Table 2.

Example 7 Fluororesin (VdF) obtained by the same method as Example 1
/TFE/HFP-67/31/2゜Mn -60,0
00, Mw/Mn -2,4) 60 g, and acrylic resin (M MA / EA = 95 / 5,
M n -13,000, M n / Mw = 2
．． 0) 40 g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition.

A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted.

The results are shown in Table 2.

Example 8 60 g of the same fluororesin as in Example 5 and 40 g of the same acrylic resin as in Example 6 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d)
I did it. The results are shown in Table 2.

Example 9 Fluororesin (VdF/
TFE/HFP-50/41/9゜Mn-90,000
, Mw/Mn = 1.7) and 40 g of the same acrylic resin as in Example 6 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition.

A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted.

The results are shown in Table 2.

Comparative Example 1 Fluororubber (VdF/TF
E/HFP-35/36/29. Mn-70,000,
Mw/Mn -2,8) 60 g and 40 g of the acrylic resin used in Example 5 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. About this composition,
A coating film was formed in the same manner as in Example 1, and the physical property test (a)
~(d) was performed. The results are shown in Table 2.

Comparative Example 2 Fluororesin (VdF/
T F E / H F P = 75 / 13 /
12, Mn -50,000, Mw/Mn
= 2.7) and 40 g of the acrylic resin used in Example 5 were dissolved in the same organic solvent as in Example 1,
A solution composition was obtained. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted. The results are shown in Table 2.

Comparative Example 3 Fluororubber (VdF/
T F E / H F P = 43 / 22 /
35, Mn-45,000, Mw/Mn-2
, 8) 60 g and the acrylic resin 4 used in Example 5
0g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted.

The results are shown in Table 2.

Comparative Example 4 Fluororesin (VdF/
T F E / H F P = 65 / 35 /
O, Mn-70,000Mw/Mn-3,1)
60 g and 40 g of the acrylic resin used in Example 5 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted. The results are shown in Table 2.

Comparative Example 5 Fluororesin (VdF/
T F E / H F P = 47 / 34 /
19, Mn-20,000, Mw/Mn-1,
5) 60 g and 40 g of the acrylic resin used in Example 5
g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted. The results are shown in Table 2.

Comparative Example 6 Fluororesin (VdF/
TFE/HF P-49/34/17
, Mn -200,000, Mw/Mn -Ll
) 60 g and 40 g of the acrylic resin used in Example 5
g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted. The results are shown in Table 2.

Comparative Example 7 Fluororesin (VdF/TF
E/RFP=47/34/ 19. Mn -90,0
00, Mw/Mn = 5.5), 40 g of the acrylic resin used in Example 5, and 40 g of the acrylic resin used in Example 5 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted. The results are shown in Table 2.

Comparative Example 8 70 g of the fluororesin obtained in Example 5 and 30 g of an acrylic resin (Mn-2,000, Mw/Mn-1,8), which is a polymer of methyl methacrylate alone and has a small molecular weight, were used in the same manner as in Example 1. It was dissolved in an organic solvent to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d) were conducted. The results are shown in Table 2.

Comparative Example 9 70 g of the fluororesin obtained in Example 5 and an acrylic resin that is a polymer of methyl methacrylate alone and has a large molecular weight (M n = 70.000. M w / M n
-2,7) and 30 g were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (
d) was performed. The results are shown in Table 2.

Comparative Example 10 70 g of fluororesin obtained in Example 5 and acrylic resin of methyl methacrylate alone (M n -17,000°M
w/M n -1,08) 30 g was dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (L) to (d) were conducted. The results are shown in Table 2.

Comparative Example 11 40 g of the fluororesin obtained in Example 5 and 60 g of the acrylic resin obtained in Example 6 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. Example 1 for this composition
A coating film was formed in the same manner as above, and the physical property tests (a) to (d)
) was carried out. The results are shown in Table 2.

Comparative Example 12 95 g of the fluororesin obtained in Example 5 and 5 g of the acrylic resin obtained in Example 6 were dissolved in the same organic solvent as in Example 1 to obtain a solution composition. A coating film was formed from this composition in the same manner as in Example 1, and the physical property tests (a) to (d)
I did it. The results are shown in Table 2.

As is clear from Tables 1 and 2, in the examples of the present invention, extremely good results were obtained in all of adhesion, durability, weather resistance, and stain resistance. On the other hand, in the comparative example, one of the properties was inferior, and a coating film with well-balanced properties could not be obtained.

That is, Comparative Example 1 is an example of a fluororubber that contains too little vinylidene fluoride and has a too low melting point, and has good stain resistance but extremely poor weather resistance.

Comparative Example 2 contains too much vinylidene fluoride and too little tetrafluoroethylene, resulting in poor durability, weather resistance, and stain resistance.

Comparative Example 3 is an example in which an excessive amount of hexafluoropropylene is used, and the weather resistance and stain resistance are extremely poor.

Comparative Example 4 is an example in which hexafluoropropylene is not used, and the durability and weather resistance are poor.

Comparative Example 5 is an example in which the Mn of the fluororesin is too low, and the durability, weather resistance, and stain resistance are poor.

Comparative Example 6 is an example in which the Mn content of the fluororesin is excessively high, and the weather resistance and stain resistance are extremely poor.

Comparative Example 7 is an example in which the M W / M n of the fluororesin is excessive, and the weather resistance is poor.

Comparative Example 8 is an example in which the Mn of the acrylic resin is too low, and the weather resistance and stain resistance are extremely poor.

Comparative Example 9 is an example in which the Mn content of the acrylic resin is excessive, and the durability and stain resistance are poor.

Comparative Example 10 is an example in which the M w / M n of the acrylic resin is too small, and the adhesion and weather resistance are extremely poor.

Comparative Example 11 is an example in which the proportion of fluororesin is too low, and the weather resistance and stain resistance are extremely poor.

Comparative Example 12 is an example in which the proportion of fluororesin is excessive, and although the stain resistance is good, the adhesion and durability are significantly inferior.

Examples 10 to 14 60 g of fluororesin and 40 g of acrylic resin having the composition ratio shown in Table 3 obtained by the same method as Example 1 were dissolved in the same organic solvent as in Example 1 to form a solution composition. Obtained. To this solution composition, 2 g of Bic Chemi Japan ■ "Disper Vic 161J" was added as a dispersant and stirred, and then T i 02 was added as a pigment at a volume fraction of 20% based on the solid content, and the mixture was stirred and dispersed. , a coating composition was prepared.

A coating film was formed from this composition in the same manner as in Example 1, and its physical properties were tested. This physical property is as described above (a
) Adhesion, (b) Durability, (C) Weather Resistance, and (e) Hardness below were measured.

The results are shown in Table 3.

(e) Hardness According to JIS K 54006.14 lead box scratch test,
The hardness of the coating film was measured.

As is clear from Table 3, if the acid value of the acrylic resin is too low, the hardness of the coating film will be low, and other physical properties will generally be slightly lowered.

Examples 15 to 17 First, the dried and purified solvents and monomers shown in Table 4 were placed in a polymerization container, and the polymerization temperature was set as shown in Table 4 under a nitrogen atmosphere, and then a catalyst was added and polymerization was carried out.
Three types of acrylic resins were obtained.

These are referred to as acrylic resins A1 to A3.

When the stereoregularity of these acrylic resins A1 to A3 was determined by the method described above, the results shown in Table 4 were obtained.

60 g of the same fluororesin as in Example 10 and 40 g of each of the above acrylic resins were dissolved in 185 g of the same solvent as in Example 10. The obtained solution was applied to a glass plate and dried to form a film with a thickness of about 100 μm, and the degree of whitening was observed with the naked eye to determine the compatibility between the fluororesin and the acrylic resin. In the evaluation, the film was not whitened, was transparent, and had good compatibility, and the film was rated ○, and the film was slightly whitened, and the compatibility was slightly poor, was rated Δ.

In addition, BIC Chemi Japan ■ is added to this solution as a dispersant.
A coating composition was obtained by adding Ig and TiO2 in a volume fraction of 20% by volume and stirring and dispersing the composition.A coating film was formed from this composition in the same manner as in Example 1. The physical property tests (a) to (C) and (e) were conducted.The results are shown in Table 5.

As is clear from Tables 4 and 5, it can be seen that the higher the isotactic steric bond component of the acrylic resin, the lower the compatibility with the fluororesin.

[Effects of the Invention] According to the present invention, weather resistance, durability derived from coating film strength,
Stain resistance, chemical stability 1. Capable of forming a coating film with excellent surface smoothness and adhesion to substrates, etc., and capable of drying at room temperature, making it suitable for use as a top coat for buildings, etc. It is possible to provide a fluorine-containing paint composition that can.

Claims (3)

[Claims] (1) Vinylidene fluoride 40 to 70 as a monomer component
% by weight, 20-50% by weight of tetrafluoroethylene and 1-30% by weight of hexafluoropropylene, the number average molecular weight Mn is 40,000-150,000, and the ratio Mw/Mn of the weight average molecular weight Mw and the number average molecular weight Mn is 5 or less, melting point is 7
50 to 90% by weight of fluororesin with a temperature of 0 to 150°C and 90% by weight of methyl methacrylate as a monomer component
Including above, Mn is 2,000 to 50,000, Mw/Mn is 1.1 to 4
An organic solvent-based fluorine-containing coating composition comprising 50 to 10% by weight of an acrylic resin in a solution state. (2) The acid value of the acrylic resin is 0.1 to 64 mgKOH
The organic solvent-based fluorine-containing coating composition according to claim (1), which is (3) The organic solvent-based fluorine-containing paint composition according to claim (1), wherein the isotactic steric bond component of the acrylic resin is 10% by weight or less.