JPH02206641A - Non-aqueous dispersion of fluorine-containing polymer and production thereof - Google Patents

Abstract

PURPOSE:To obtain non-aqueous dispersion of fluorine-containing polymer useful as weather-resistant coating material giving smooth and transparent coating film by polymerizing (meth)acrylate having fluoroalkyl group in organic solvent and in the presence of specific dispersing stabilizer. CONSTITUTION:(C) A monomer mixture containing >=5wt.% (meth)acrylate having fluoroalkyl group (preferably perfluoromethyl methacrylate, etc.) is polymerized in (A) an organic solvent (preferably aliphatic hydrocarbon-based solvent) and in the presence of (B) dispersing stabilizer composed of fluorine- containing polymer having an unit derived from fluoroolefin (e.g. copolymer of chlorotrifluoroethylene, cyclohexyl vinylether and hydroxybutyl vinylether) using radical polymerization initiator to afford the aimed dispersion in which a polymer solely insoluble or unable to be stably dispersed in organic solvent is dispersed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a non-aqueous fluoropolymer dispersion and a method for producing the same.

[Prior Art] Conventionally, copolymers made by copolymerizing fluoroolefins, cyclohexyl vinyl ether, and various other monomers are soluble in organic solvents at room temperature, and when used as paints, they are transparent and have high gloss. Moreover, it is known to provide a coating film with the excellent properties of fluororesin, such as high weather resistance, water/oil repellency, stain resistance, and non-adhesion (Japanese Patent Publication No. 55-1989).
No. 44083) Its use is increasing in fields such as architecture.

On the other hand, a method has been described in which a stable non-aqueous dispersion type paint is produced by polymerizing a radically polymerizable unsaturated monomer using the above-mentioned fluororesin as a dispersion stabilizer and an aliphatic hydrocarbon as a solvent ( Japanese Patent Publication No. 62-25103).

Compared to solvent-based paints, such non-aqueous dispersion type paints are desirable from the viewpoint of air pollution because they are mainly less toxic than solvent-based paints and can use photochemically inert aliphatic hydrocarbons as dispersion media. It is expected to be a new form of paint because of its excellent paintability.

However, regarding the fluorine-containing non-aqueous dispersion type paint, there is no mention of transparency (in fact, such a composition can only provide an opaque coating film).

Furthermore, the above-mentioned dispersion-type paints tend to float during coating film formation, resulting in poor appearance such as yuzu skin, and various additives such as leveling agents must be added.

[Problems to be Solved by the Invention] Conventional non-aqueous dispersion paints containing fluororesin have the above-mentioned structure, so they have poor transparency of the paint film, and furthermore, they float on the paint film and cause yuzu skin, etc. There was a problem that it was easy to occur.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes dispersing a polymer that is insoluble or cannot be stably dispersed in an organic solvent alone. Due to the presence of a stabilizer, a non-aqueous dispersion in which the polymer is dispersed,
Fluorine-containing polymer (A) having units based on acrylate or methacrylate having a fluoroalkyl group
and the dispersion stabilizer is a fluorine-containing polymer (B) having units based on a fluoroolefin. Polymer (B
) in the presence of a dispersion stabilizer consisting of a monomer mixture containing an acrylate or methacrylate having a fluoroalkyl group, in which the polymer obtained by polymerizing the monomer mixture is insoluble or stable alone in the organic solvent. The present invention provides a method for producing a non-aqueous fluoropolymer dispersion, which is characterized by polymerizing a monomer mixture having a composition that forms a polymer that cannot be dispersed in the fluoropolymer.

In the present invention, the organic solvent can be freely selected from those commonly used as solvents for solution-type paints and those used as solvents for non-aqueous dispersion-type paints. Among these, aliphatic hydrocarbon solvents that have low toxicity and are photochemically inactive are preferred. Examples of aliphatic hydrocarbon solvents include hexane, heptane, octane, cyclohexane, cyclohebutane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, mineral spirits, and aliphatic naphtha. These organic solvents may be used alone or in combination of two or more. Also, aromatic hydrocarbons such as benzene, toluene, xylene, etc.; alcohol-based, ether-based, ester-based and ketone-based solvents such as isopropyl alcohol, n-butyl alcohol, l-butyl alcohol, te
rt-butyl alcohol, octyl alcohol, cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, methyl isobutyl ketone, diisobutyl ketone, ethyl acyl ketone, methyl hexyl ketone,
Ethyl butyl ketone, ethyl acetate, isobutyl acetate, acyl acetate, 2-ethylhexyl acetate, and the like may be mixed and used to adjust solubility.

The dispersion stabilizer in the present invention is a fluoropolymer (B) having units based on fluoroolefins. As the fluorine-containing polymer (B), a polymer that can be dissolved or stably dispersed alone in the organic solvent is used. When selecting or synthesizing the fluoropolymer (B),
Whether such a polymer can be dissolved or stably dispersed in an organic solvent by itself is determined by its solubility coefficient (hereinafter referred to as SP).
This value can be used as a guideline. Here, the SP values are R, F, Fedors, Polym, Eng.

Sci., 14 [21147 (1974)]. SP of fluoropolymer
(hereinafter referred to as ΔSP value)
is about 1.8 or less, usually the fluoropolymer can be dissolved or stably dispersed in the organic solvent alone. Further, when the ΔSP value is larger than S, the fluoropolymer is usually insoluble or cannot be stably dispersed in an organic solvent alone. However, in some cases, the relationship between the ΔSP value and solubility may collapse.

Further, it is preferable that the fluoropolymer (B) has coating film-forming properties by itself from the viewpoint of the physical properties of the coating film using the fluoropolymer non-aqueous dispersion of the present invention. Specifically, the intrinsic viscosity (hereinafter referred to as [η]) measured at 30°C in tetrahydrofuran is 0. O1~4.0dj2/g
Preferably, the molecular weight is within a certain range. Further, the fluoropolymer (B) having a fluorine content of 10% by weight or more based on units based on fluoroolefins is preferable because it exhibits good weather resistance even when used as a weather-resistant paint base. In addition, when the fluoropolymer (B) is a polymer having a functional group that can react with the fluoropolymer (B) or with a curing agent, a cured product having a three-dimensional network structure can be obtained by the reaction. Further, it is preferable that the fluorine-containing polymer has a group that can react with the monomer forming the fluorine-containing polymer (A), specifically a double bond, etc. This is preferable from the viewpoint of long-term stability of the non-aqueous dispersion because it enables graft bonding with the polymer (B).

More specifically, a copolymer of a fluoroolefin and a monomer copolymerizable with the same may be mentioned. Here, examples of the fluoroolefins include fluoroolefins having about 2 to 4 carbon atoms, such as tetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, hexafluoropropylene, and pentafluoropropylene. Among them, tetrafluoroethylene,
Bare olefins such as chlorotrifluoroethylene and hexafluoropropylene are preferred; copolymerizable monomers include vinyl ethers, vinyl esters, allyl ethers, allyl esters, olefins,
Examples include heroolefins, acryloyl compounds, methacryloyl compounds, unsaturated carboxylic acids and esters thereof.

Further, such monomers may include unsaturated monomers having reactive groups such as hydroxyalkyl vinyl ether, hydroxyalkyl vinyl ether, glycidyl vinyl ether, glycidyl allyl ether, and hydrolyzable silyl group-containing vinyl compounds. . The monomer can be appropriately selected for purposes such as adjusting solubility depending on the type of organic solvent. In addition, when the produced non-aqueous fluoropolymer dispersion is used as a paint base, vinyl ether, vinyl ester, allyl ether, or allyl ester may be added as a copolymer component in terms of gloss, pigment dispersibility, coating film properties, etc. It is preferable to include it as In particular, linear chains having about 1 to 15 carbon atoms, such as ethyl vinyl ether, inbutyl vinyl ether, n-butyl vinyl ether, cyclohexyl vinyl ether, vinyl acetate, n-butyric acid vinyl ester, n-butyl allyl ether, valeric acid allyl ester, etc. , vinyl ether, vinyl ester, allyl ether, and allyl ester having a branched or alicyclic alkyl group are preferably employed. In addition, if the fluorine-containing copolymer based on the above monomer has insufficient solubility in the organic solvent used, copolymerization of macromonomers that provide side chains to improve solubility, graft polymerization, etc. It is preferable to measure the improvement in solubility in organic solvents. For example, when an aliphatic hydrocarbon in which the fluorine-containing copolymer is difficult to dissolve is used as an organic solvent, it is preferable to graft, block, or macromonomize the following acrylic copolymer or polyester and copolymerize it.

The acrylic copolymer is preferably composed of the following weight components.

■ Vinyl compounds: styrene, vinyltoluene, a-
Vinyl compounds such as methylstyrene, vinyl acetate, acrylonitrile, and methacrylonitrile; (cyclo)alkyl (meth)acrylate: methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, Butyl acrylate, i-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2
- alkyl or cycloalkyl esters of acrylic or methacrylic acid having 1 to 24 carbon atoms, such as ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, etc.; Hydroxy (meth)acrylate: Hydroxyalkyl ester of acrylic acid or methacrylic acid having 1 to 24 carbon atoms, such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc.; ■ α , β-ethylenically unsaturated carboxylic acids such as nialic acid, methacrylic acid, itaconic acid, crotonic acid, etc.;
The β-ethylenically unsaturated carboxylic acid niacryl copolymer can be obtained by copolymerizing monomers selected from the above (1) to (2), but the monomer shown in (2) is always copolymerized. In addition, at that time, 5 to 40%, preferably 10 to 2%, of a hydroxyl group-containing monomer such as the monomer (1) above is added.
5%, and 0.5% α,β-unsaturated carboxylic acid such as ■
It is necessary to contain ~5%, preferably 1-4%.

Furthermore, the most suitable example of the polyester that can be used in the present invention is poly(12-hydroxystearic acid), which is described in Tadahiro Miba's "Chemistry of Synthetic Resins", p. 251 (1968), Gihodo. It is obtained by heating and dehydrating 12-hydroxystearic acid, and the reaction formula is expressed as shown in the following formula (I).

This dehydration condensation reaction can be carried out using known catalysts such as phosphoric acid, p-
In the presence of toluenesulfonic acid, tetra-n-nibutyl titanate, tetraisopropyl titanate, etc., or in the presence of methanesulfonic acid, etc. as described on page 14 of Australian Patent No. 493,015, or As described in Japanese Publication No. 54-34009, it is preferably carried out by removing the produced water from the system while heating at 120 to 200°C, preferably 140 to 190°C, in the absence of a catalyst. Alternatively, the dehydration and esterification reaction can be carried out by passing an inert gas such as nitrogen through the reaction system, or by conducting the dehydration esterification reaction with aromatic hydrocarbons, which form an azeotrope with water.
For example, it is advantageous to carry out the reaction in the presence of toluene or xylene, and remove the produced water azeotropically from the reaction system. The degree of progress of the esterification reaction due to intermolecular dehydration can be determined by measuring the amount of distilled water and the acid value of the reactant, and the polyester used in the present invention has an acid value of 20.
A value between 120 and 120 is practically suitable.

12-hydroxystearic acid, which is usually commercially available, is produced by hydrolysis of hydrogenated castor oil.
Although it contains small amounts of valmitic acid and stearic acid as impurities, the presence of these does not pose a particular problem as a raw material for producing the dispersant of the present invention.

The fluoropolymer (A) in the present invention is a fluoropolymer having units based on acrylate or methacrylate having a fluoroalkyl group. Such a fluoropolymer (A) is a polymer that cannot be dissolved or stably dispersed in an organic solvent by itself.

Examples of the acrylate or methacrylate having a fluoroalkyl group include compounds represented by the following formula.

CHx: CCOO-+CH* +? lRf In the above formula, R
is hydrogen or a methyl group, n is an integer of 1 to 11, R
f is a linear, branched or alicyclic fluoroalkyl group having about 1 to 21 carbon atoms. Particularly preferred is one in which the fluoroalkyl group is a barfluoroalkyl group. In addition, in the above formula, n is an integer of 1 to 4, and Rf is the number of carbon atoms l.
A linear, branched, or alicyclic perfluoroalkyl group of ~1O is preferred from the viewpoint of ease of availability, polymerizability, and handleability. Examples of the acrylate or methacrylate having such a fluoroalkyl group include perfluoromethylmethyl acrylate,
Perfluoromethyl methyl methacrylate, perfluoropropyl methyl acrylate, perfluoropropyl methyl methacrylate, perfluorooctyl undecyl acrylate, perfluorooctyl undecyl methacrylate, perfluoropropyl propyl acrylate, perfluoropropyl propyl methacrylate, 2
-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, 2-perfluoroisononylethyl methacrylate, perfluoroisononylmethyl acrylate, perfluoroisononylmethyl methacrylate, etc. Among these, perfluoromethylmethyl acrylate, perfluoroisononylmethyl methacrylate, 2-perfluorooctylethyl acrylate and 2-perfluorooctylethyl methacrylate are particularly preferred.

In addition, the fluoropolymer (A) may contain other acrylates, methacrylates,
It may have a unit copolymerized with a vinyl aromatic compound, α, β-ethylenically unsaturated acid, or the like. acrylate,
Examples of methacrylates include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, and propyl methacrylate. , isopropyl methacrylate, butyl methacrylate,
C of acrylic acid or methacrylic acid such as hexyl methacrylate, octyl methacrylate, lauryl methacrylate, etc.
+-+a alkyl ester/glycidyl acrylate,
Glycidyl meccrylate; 02- of acrylic acid or methacrylic acid such as allyl acrylate and allyl methacrylate. Alkenyl ester; 02-8 hydroxyalkyl ester of acrylic acid or methacrylic acid such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate; Cs of acrylic acid or methacrylic acid such as allyloxyethyl acrylate, allyloxymethacrylate -+s alkenyloxyalkyl ester.

Examples of vinyl aromatic compounds include styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene vinylpyridine, and the like.

Furthermore, examples of the α,β-ethylenically unsaturated acid include acrylic acid, methacrylic acid, and itaconic acid. In addition to these, it may also contain polymerized units of acrylonitrile, methacrylaterile, methyl isopropenyl ketone, vinyl acetate, vinyl ester, vinyl propionate, vinyl bivalate, and the like.

Furthermore, when the fluoropolymer (A) contains units based on acrylate or methacrylate having a fluoroalkyl group in a proportion of 5% by weight or more, it is possible to completely suppress the lifting of the coating film and the occurrence of yuzu skin. , a coating film with extremely excellent smoothness can be obtained. In addition, since it contains units based on acrylate or methacrylate having such a fluoroalkyl group, the difference in refractive index with the fluoropolymer (B), which is a dispersion stabilizer, is small, resulting in a coating with excellent transparency. membrane can be obtained. Furthermore, there is no particular upper limit to the amount of units based on acrylate or methacrylate having a fluoroalkyl group, but even if too large a quantity is included, there will be no improvement in the effect of preventing the occurrence of flaky skin or yuzu skin, and rather it will be expensive. There may be adverse effects such as. Usually, an amount of about 60% by weight or less is employed. Further, from the viewpoint of paintability and physical properties of the coating film, it is preferable that the composition contains 40% by weight or more of units based on acrylate or methacrylate-1 having a fluoroalkyl group and other acrylates or methacrylates.

The non-aqueous dispersion of the present invention can be produced by the following method.

A monomer mixture containing an acrylate or methacrylate having a fluoroalkyl group in an organic solvent in the presence of a dispersion stabilizer consisting of a fluorine-containing polymer (B) having units based on fluoroolefins, the monomer mixture comprising: This method involves polymerizing a monomer mixture having a composition that results in a polymer that is insoluble or cannot be stably dispersed in the organic solvent alone.

Here, the monomer mixture may contain, in addition to the acrylate or methacrylate having a fluoroalkyl group, the compounds exemplified in the explanation of the fluoropolymer (A) above, and the composition of the monomer mixture It is preferable to select the value appropriately in consideration of the type of organic solvent used, desired physical properties, etc., and can be used as a guideline by referring to the above-mentioned concept of the ΔSP value.

In order to maintain dispersion stability for an extremely long period of time, it is preferable that the fluorine-containing polymer (B) and the fluorine-containing polymer (A), which are dispersion stabilizers, are graft-bonded. In order to achieve this, there is a method in which a functional group capable of graft bonding is introduced into the fluoropolymer (B) in advance. As a method for introducing a functional group capable of graft bonding, if the fluorine-containing polymer (B) has a hydroxyl group, an unsaturated group may be introduced by reacting incyanate alkyl acrylate or an unsaturated carboxylic acid. There is a method.

Moreover, the polymerization of the above-mentioned monomer mixture is performed using a radical polymerization initiator. Usable radical polymerization initiators include, for example, 2,2-azoisobutyronitrile, 2
, 2'-Azobis(2,4-dimethylvaleronitrile and other azo-based initiators; benzoyl peroxide, lauryl peroxide, tart-butyl peroctoate and other peroxide-based initiators; these polymerization initiators is generally per 100 parts by weight of the monomer mixture subjected to polymerization.
It can be used in a range of 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

Polymerization can be carried out by a method known per se, and the reaction temperature during polymerization can generally be within the range of 60 to 160°C, and the reaction can usually be completed in 1 to 15 hours. .

Furthermore, in the present invention, in the combination of the dispersion stabilizer made of the fluoropolymer (B) and the fluoropolymer (A), by setting the difference in refractive index within the range of 0 to 0.05, A coating film with very good transparency can be obtained.

Further, the amount of the dispersion stabilizer resin used can vary widely depending on the type of resin, etc., but in general, the amount of the dispersion stabilizer resin used is 30% based on the total amount of the monomer to be polymerized and the dispersion stabilizer.
A range of from 5 to 45% by weight is advantageous.

Furthermore, the total concentration of the monomer and dispersion stabilizer in the organic solvent is generally 30 to 70% by weight, preferably 30 to 70% by weight.
Desirably, it is 60% by weight.

The non-aqueous dispersion provided by the present invention can be used as it is, but if necessary, colorants, plasticizers, curing agents, etc. can be added thereto. Further, if necessary, an ultraviolet absorber or a light stabilizer may be added. Although the surface layer of the clear coating film in the present invention is mainly composed of a fluorine-containing polymer with good weather resistance, ultraviolet rays in sunlight can pass through such a transparent coating film and deteriorate the base coat coating film. . Therefore, by incorporating an ultraviolet absorber or a light stabilizer, the weather resistance of the entire coating film can be improved.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In Examples and Comparative Examples, parts and % are both parts by weight and % by weight. Further, the particle size was measured by a light scattering method using laser light.

[Examples] Example 1 Synthesis of dispersion A Lolotrifluoroethylene, cyclohexyl vinyl ether and hydroxybutyl vinyl ether were each mixed in 48.
4.42.0.9.6% by weight, sp value 10.1. 50 parts of a dispersion stabilizer made of a copolymer having an intrinsic viscosity of 0.20 and a refractive index no' of 1.47 as measured at 30°C in tetrahydrofuran were added to 40 parts of xylene and 80 parts of heptane in a 500 cc four-way flask equipped with a stirrer. The following monomers and polymerization initiator were added dropwise over a period of 3 hours. After the addition, the mixture was aged for 1 hour and 30 minutes, and then 20 parts of n-butyl acetate was added dropwise and slowly cooled to room temperature.

Methyl methacrylate 28 parts 2-perfluorooctylethyl methacrylate 12 parts Acrylonitrile 22 parts 2-hydroxyethyl methacrylate 12 parts Tert-butylperoxy 2-ethylhexanoate 1.2 parts The obtained liquid has a non-volatile content of 50% and a polymer. It was a milky white stable dispersion with a particle size of 0.3 μm.

Furthermore, polymers based on the above monomers were insoluble and could not be stably dispersed in the above solvents in the absence of a dispersion stabilizer. No precipitation or coarse particles were observed even after being left at room temperature for 3 months.

Example 2 Synthesis of dispersion B Lolotrifluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether and hydroxybutyl vinyl ether were each mixed at 54.5°, 17.7.16°, and 9.10°.
．． Dispersion stabilizer 50 made of a copolymer containing 9% by weight, having an sp value of 9.8, an intrinsic viscosity measured at 30° C. in tetrahydrofuran of 0.20, and a refractive index n20 of 1.46. The solution was dissolved in 25 parts of xylene and 70 parts of butane in a 500 cc four-bottle flask equipped with a stirrer, heated to reflux, and the following monomers and polymerization initiator were added dropwise over 3 hours. After the dropwise addition, the mixture was aged for 1 hour and 30 minutes. After this, 25 parts of n-butyl acetate was added dropwise, and the mixture was slowly cooled to room temperature.

Methyl methacrylate 17 parts 2-perfluorooctylethyl methacrylate 20 parts Acrylonitrile 20 parts 2-hydroxyethyl methacrylate 810 parts Tertiary-butyl peroxy 2-ethylhexanoate 1.0 parts The resulting liquid contains non-volatile components It was a milky white stable dispersion with a polymer particle size of 51% and a polymer particle size of 0.4 μm.

Furthermore, polymers based on the above monomers were insoluble and could not be stably dispersed in the above solvents in the absence of a dispersion stabilizer. No precipitation or coarse particles were observed even after being left at room temperature for 3 months.

Example 3 Introduction of double bond into dispersion stabilizer 100 parts of the dispersion stabilizer used in Example 2 was mixed with 10 parts of xylene.
Add 0.8 parts of succinic anhydride and 0.03 parts of triethylamine, and heat to 50°C.
Stir for 8 hours. To this solution was added 0.6 parts of glycidyl methacrylate and 0.6 parts of 4-tert-butylpyrocatechol. O1 part diethylaminoethanol
0.07 part was added and refluxed for 5 hours to introduce a copolymerizable double bond into the dispersion stabilizer molecular chain.

Synthesis of dispersion C Xylene solution of the dispersion stabilizer introduced with the above double bond 10
0 part was concentrated to a solid content concentration of 60%, 60 parts of heptane was added, and the mixture was heated to reflux in a 500 cc four-tube flask equipped with a stirrer, and the monomer and polymerization initiator used in Example 2 were added dropwise over 3 hours. After aging for 1 hour and 30 minutes, acetic acid n
-25 parts of butyl was added dropwise and slowly cooled to room temperature.

The obtained liquid had a non-volatile content of 51% and a polymer particle size of 0°4.
It was a milky white stable dispersion of .mu.m.

Even after being left at room temperature for 3 months, no sedimentation or generation of coarse particles was observed.

Example 4 Synthesis of dispersion Contains tetrafluoroethylene, chlorotrifluoroethylene, ethyl vinyl ether, and hydroxybutyl vinyl ether in proportions of 26.4, 30.8, 30.5° and 12.3% by weight, respectively, and SP value 9.7, intrinsic viscosity measured at 30°C in tetrahydrofuran is 0.20, and refractive index is 1.
50 parts of the copolymer No. 42 was dissolved in 25 parts of xylene and 60 parts of heptane in a 500 cc four-tube flask equipped with a stirrer, heated to reflux, and the following monomers and polymerization initiator were added dropwise over 3 hours. After aging for 30 minutes, acetic acid n-
20 parts of butyl was added dropwise and slowly cooled to room temperature.

2-perfluorooctylethyl methacrylate 25 parts Acrylonitrile 17 parts 2-hydroxyethyl methacrylate 8 parts Tertiary-butyl peroxy 2-ethylhexanoate 0.7 parts The obtained liquid had a non-volatile content of 48% and a particle size of the polymer particles. It was a milky white stable dispersion with a diameter of 0.4 μm.

Furthermore, polymers based on the above monomers were insoluble and could not be stably dispersed in the above solvents in the absence of a dispersion stabilizer. No precipitation or coarse particles were observed even after being left at room temperature for 3 months.

Comparative Example 1 Synthetic dispersion stabilizer for dispersion E (manufactured by Asahi Glass Co., Ltd. "Lumiflon LF200J weight average molecular weight approx. 502mm, fluorine atom content 28%) 108 parts hebutane 102 parts acetic acid n-
8 parts of butyl was charged into a flask and heated to reflux, the following monomers and polymerization initiator were added dropwise over 3 hours, and after further aging for 2 hours, 2 parts of n-butyl acetate was added.
Added 6 copies.

Styrene 15 parts Methyl methacrylate 40 parts Acrylonitrile 30 parts 2-hydroxyethyl methacrylate 15 parts Tert-butyl peroxy 2-ethylhexanoate 1.5 parts The obtained liquid had a non-volatile content of 49% and a polymer particle size of 0. 52μm
It was a stable dispersion. Furthermore, polymers based on the above monomers were insoluble and could not be stably dispersed in the above solvents in the absence of a dispersion stabilizer. No precipitation or coarse particles were observed even after being left at room temperature for 3 months.

Polyisocyanate (manufactured by Nippon Polyurethane Co., Ltd.,
Coronate EH) is blended ([OH]/[NCO]=l/
1 molar ratio) to prepare a clear coating film, which was dried at room temperature for 7 days. However, 0.03 phr of dibutyltin silaurylate as a curing catalyst and 10 phr of an ultraviolet absorber (Biosorb 130 manufactured by Kyodo Yakuhin Co., Ltd.) were added.

Table 1 below shows the results of various experiments conducted on the above clear coating film.

[Effects of the Invention] The non-aqueous dispersion of the fluoropolymer of the present invention is extremely useful as a weather-resistant paint or a raw material for a weather-resistant paint, and does not cause problems such as lifting or yuzu skin when forming a paint film (and has a smooth, smooth surface). It is possible to obtain a coating film with excellent transparency.Also, since the coating film is transparent, a coating film with excellent image clarity can be obtained even when pigments are added.

Claims (1)

[Scope of Claims] 1. A non-aqueous dispersion in which a polymer that is insoluble or cannot be stably dispersed in an organic solvent alone is dispersed due to the presence of a dispersion stabilizer, which comprises: The polymer is
Fluorine-containing polymer (A) having units based on acrylate or methacrylate having a fluoroalkyl group
A non-aqueous dispersion of a fluoropolymer, wherein the dispersion stabilizer is a fluoropolymer (B) having units based on a fluoroolefin. 2. A monomer mixture containing an acrylate or methacrylate having a fluoroalkyl group in an organic solvent in the presence of a dispersion stabilizer consisting of a fluoropolymer (B) having units based on a fluoroolefin, A non-aqueous dispersion of a fluoropolymer, characterized in that the polymer obtained by polymerizing the monomer mixture is a monomer mixture having a composition that is insoluble or cannot be stably dispersed in the organic solvent alone. manufacturing method.