JPH037784A - Aqueous dispersion of fluorine-based polymer and fluorine-based polymer-containing aqueous dispersion - Google Patents

Abstract

PURPOSE:To obtain the title dispersion having excellent storage stability and film-forming properties, making a coating film having excellent adhesivity to substrates, by subjecting a monomer mixture comprising a (meth)acrylic acid ester, etc., to emulsion polymerization in the presence of particles of fluorinated vinylidene-based polymer. CONSTITUTION:The aimed dispersion prepared by subjecting (B) 5-95 pts.wt. monomer mixture comprising (i) an acrylic acid (1-18C) alkyl ester and/or methacrylic acid (1-18C) alkyl ester and optionally (ii) an ethylene-based unsaturated compound copolymerizable with the component (i) to emulsion polymerization in the presence of (A) 100 pts.wt. fluorinated vinylidene-based polymer in an aqueous medium and having 0.05-3mum average particle diameter.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an aqueous fluoropolymer dispersion and an aqueous fluoropolymer-containing dispersion, and more specifically, it has excellent storage stability and film-forming properties, and Contains an aqueous dispersion of a fluoropolymer and a fluoropolymer and a water-soluble resin and/or a water-dispersible resin, forming a film with excellent properties such as adhesion, chemical resistance, and mechanical strength. Concerning aqueous dispersions.

In addition to paints, these aqueous dispersions can be used as fiber treatment agents, paper processing materials, floor coating materials, carpet parakink materials, and the like.

(Prior Art) Fluororesins have excellent chemical resistance and solvent resistance, as well as good heat resistance, weather resistance, gas impermeability, radiation resistance, and electrical insulation properties. For this reason, fluororesin
Lining materials, corrosion resistance, impregnated materials for porous materials (e.g. asbestos sheets, glass sheets, felt sheets, paper, etc.), backing materials, coating materials, acid resistance, alkaline earth metals are required to have electrical insulation properties. It is widely considered to be used as a material when sprayed on the surface of a material, as a paint when baked, as a laminate film material, a non-tackifying material for fibers, a water repellent material, a coating material for floors, etc.

However, fluororesins have poor processability, for example, poor film-forming properties,
Baking at high temperatures requires processing, which tends to cause coating defects such as pinholes, and also has the disadvantage of poor adhesion to substrates, transparency, and mechanical strength such as tensile strength. For this reason, the reality is that fluororesins are used only for limited purposes and are not widely used.

In order to improve the above-mentioned drawbacks of fluororesins, a method for producing a powdery composition in which methyl acrylate and isobutylene are copolymerized in the presence of vinylidene fluoride polymer obtained by suspension polymerization (Japanese Patent Publication No. 54-15077) Public bulletin),
Fluorine-containing aqueous dispersion in which a water-soluble resin is blended with a fluorine-containing random copolymer (Japanese Unexamined Patent Publication No. 157159/1983),
100 to 500 parts by weight of an ethylenically unsaturated carboxylic acid ester and/or a monomer copolymerizable therewith to 100 parts by weight of a fine particle dispersion obtained by finely dispersing a fluoropolymer using a surfactant. A method for producing a fluoropolymer composite by emulsion polymerization (Japanese Unexamined Patent Publication No. 63-31
No. 2836) and the like have been proposed.

(Problems to be Solved by the Invention) According to the research conducted by the present inventors, it has been found that the above-mentioned conventional methods have not been able to sufficiently improve the drawbacks of fluororesin, and there are still problems remaining for practical application. did.

In the case of the powder composition described in JP-A-54-15077, the particle size of the obtained polymer is usually as large as 50 to 200 μm, so the coating film formed using this powder composition has poor weather resistance. Poor properties, chemical resistance, etc. Japanese Patent Publication No. 59-157
The fluorine-containing aqueous dispersion described in Publication No. 159 has low storage stability, and the coating formed using this dispersion does not have sufficient properties such as durability. Also, JP-A-63-312
The composite obtained by the method described in Publication No. 836 has poor weather resistance, which is a characteristic of fluororesins, because the amount of ethylenically unsaturated carboxylic acid ester and/or monomer copolymerizable therewith is too large relative to the seed particles. , chemical resistance etc. will be lost.

Therefore, the present invention improves the above drawbacks while retaining the excellent properties inherent to fluororesin, and has excellent storage stability and film forming properties, as well as properties such as adhesion to substrates, chemical resistance, and mechanical strength. The object of the present invention is to provide an aqueous fluoropolymer dispersion that forms a film with excellent properties.

(Means for Solving the Problems) The present inventors have developed a method that can be obtained by emulsion polymerizing a monomer mixture having a specific composition in an aqueous medium using vinylidene fluoride polymer particles as seed particles, and The inventors have found that the above object can be achieved by using an aqueous fluoropolymer dispersion in which the combined particles have a particle size within a specific range, and have completed the present invention based on this knowledge.

That is, the present invention provides vinylidene fluoride polymer particles 1
In the presence of 00 parts by weight, the alkyl group has 1 to 18 carbon atoms.
acrylic acid alkyl ester and/or methacrylic acid alkyl ester having an alkyl group of several months to 18 carbon atoms, and optionally an ethylenically unsaturated compound copolymerizable with these. Concerning a combined aqueous dispersion.

Furthermore, the present invention provides the above fluoropolymer aqueous dispersion 95
-30 parts by weight (solid content), and 5 to 70 parts by weight (solid content) of an aqueous dispersion of a water-soluble resin and/or water-dispersible resin. .

The present invention will be explained in detail below.

Vinylidene fluoride polymers used as seed particles in the present invention include vinylidene fluoride homopolymers, vinylidene fluoride and trifluorochloroethylene, hexafluoropropylene, tetrafluoroethylene, which can be copolymerized with vinylidene fluoride, Fluorine-containing ethylenically unsaturated compounds such as vinyl fluoride, hexafluoroisobutylene, perfluoroacrylic acid, cyclohexyl vinyl ether,
Examples include copolymers with fluorine-free ethylenically unsaturated compounds such as hydroxyethyl vinyl ether and fluorine-free diene compounds such as butadiene, isoprene, and chlorobrene.

Among these, vinylidene fluoride homopolymer, vinylidene fluoride/ethylene tetrafluoride copolymer, vinylidene fluoride/ethylene tetrafluoride/propylene hexafluoride copolymer, etc. are preferably used.

Although the above vinylidene fluoride polymer can be obtained by various methods, in the present invention, a vinyl+/dene fluoride polymer obtained by emulsion polymerization is particularly preferably used. Therefore, in the present invention, vinylidene fluoride homopolymer, vinylidene fluoride/ethylene tetrafluoride copolymer, vinylidene fluoride/ethylene tetrafluoride/propylene hexafluoride copolymer, etc. obtained by emulsion polymerization are used. It is particularly preferably used.

The vinylidene fluoride polymer may be added in any state as long as it is dispersed as particles in the aqueous medium.
As mentioned above, in the present invention, vinylidene fluoride polymers obtained by emulsion polymerization are preferred, and in this case, since they are produced as an aqueous dispersion, it is convenient to use them as they are as an aqueous dispersion. Such an aqueous dispersion of a vinylidene fluoride polymer can be prepared by, for example, adding raw material monomers to an aqueous medium in the presence of an emulsifier, a polymerization initiator, a pH adjuster, etc., as described below, by a normal emulsion polymerization method. It can be produced by emulsion polymerization.

The particle size of the vinylidene fluoride polymer particles varies depending on the particle size of the polymer particles in the target fluoropolymer aqueous dispersion, but is usually in the range of 0.04 to 2.9 μm. It is preferable to have one.

The vinylidene fluoride polymer particles used as seed particles in the present invention are preferably those obtained by emulsion polymerization. For example, when vinylidene fluoride polymer particles obtained by suspension polymerization are used as seed particles, the resulting polymer The particle diameter becomes as large as 50 to 200 μm, making it impossible to achieve the object of the present invention.

The alkyl group of the monomer to be emulsion polymerized in the presence of the vinylidene fluoride polymer particles has 1 to 18 carbon atoms.
Examples of acrylic acid alkyl esters include methyl acrylate, ethyl acrylate, propyl acrylate,
Examples include 1Wn-butyl acrylate, isobutyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate. Acrylic acid alkyl esters in which the alkyl group has 1 to 8 carbon atoms, particularly acrylic acid alkyl esters in which the alkyl group has 1 to 5 carbon atoms, are preferably used.

Examples of methacrylic acid alkyl esters in which the alkyl group has 1 to 18 carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n-methacrylate.
-butyl, isobutyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate,
Examples include 2-ethylhexyl methacrylate and lauryl methacrylate. The number of carbon atoms in the alkyl group is 1
-8 methacrylic acid alkyl esters, particularly methacrylic acid alkyl esters in which the alkyl group has from several months to 5 carbon atoms, are preferably used.

Examples of ethylenically unsaturated compounds copolymerizable with the above acrylic acid alkyl esters and methacrylic acid alkyl esters include (a) functional vinyl compounds and (b) vinyl compounds other than the functional vinyl compounds mentioned in (a) above. be able to.

Examples of the functional vinyl compound (a) include acrylic acid, methacrylic acid, fumaric acid, crotonic acid, and itaconic acid.
, β-unsaturated carboxylic acids, vinyl compounds such as vinyl acetate, acrylamide, methacrylamide, N-methylacrylamide), N-methylmethacrylamide, methylolacrylamide, N-methylolmethacrylamide, N-alkylacrylamide, N-alkyl methacrylamide, N, N-dialkyl acrylamide, N
, amide compounds such as N-dialkylmethacrylamide, acrylic acid esters such as 2-hydroxyethyl acrylate, N-dialkylaminoethyl acrylate, glycidyl acrylate, and fluoroalkyl acrylate, dialkylaminoethyl methacrylate, and fluoromethacrylate. Examples include alkyl, methacrylic acid esters such as 12-hydroxyethyl methacrylate, glycidyl methacrylate, and ethylene glycol dimethacrylate, and vinyl ether compounds such as allyl glycidyl ether. Among these, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, N-methylolacrylamide,
N-methylol methacrylamide, 2-hydroxyethyl acrylate, methacryl #2-hydroxyethyl, allyl glycidyl ether, and the like are preferably used.

Vinyl compounds (b) include conjugated dienes such as 1,3-butadiene and isoprene, aromatic vinyl compounds such as styrene, α-methylstyrene, and halogenated styrene;
Examples include divinyl compounds such as divinylbenzene, and vinyl cyanides such as acrylonitrile and methacrylonitrile.

Among these, 1,3-butadiene, styrene, acrylonitrile and the like are preferably used.

Among these ethylenically unsaturated compounds, the functional 11-vinyl compound (a) accounts for less than 50% by weight of the monomer mixture, and the vinyl compound (b) accounts for 30% by weight of the monomer mixture. It is preferable to use the proportion less than

In addition, as for the above-mentioned acrylic acid alkyl ester, methacrylic acid alkyl ester and the ethylenically unsaturated compound used as necessary, monomers such as those exemplified above are used alone or as a mixture of two or more types. be able to.

When an acrylic acid alkyl ester and a methacrylic acid alkyl ester are used together, the ratio of the two is not particularly limited and can be appropriately determined depending on the properties of the intended fluoropolymer. Further, the proportion of the acrylic acid alkyl ester in the monomer mixture is preferably less than 80% by weight, particularly preferably less than 60% by weight. If it exceeds 80% by weight, chemical resistance, weather resistance, mechanical strength, etc. will deteriorate, which is not preferable.

The aqueous fluoropolymer dispersion of the present invention is prepared by mixing 5 to 95 parts by weight, preferably 20 to 9 parts by weight, of the monomer mixture 2 in the presence of 100 parts by weight of the vinylidene fluoride polymer particles.
Obtained by emulsion polymerization of 0 parts by weight in an aqueous medium.

If the amount of the monomer mixture used is less than 5 parts by weight, processability (film formability) and adhesion to the substrate will be poor, while if it exceeds 95 parts by weight, the weather resistance and chemical resistance of the hnylidene fluoride polymer itself will be degraded. Characteristics such as gender are lost, making it undesirable.

Although it is not clear what kind of product is obtained in the above emulsion polymerization, the monomer is mainly absorbed or adsorbed into the vinylidene fluoride polymer particles and polymerizes while swelling the particles. it is conceivable that.

The emulsion polymerization described above can be performed under normal emulsion polymerization conditions. For example, emulsifiers, polymerization initiators, pl in an aqueous medium
-1 A regulator, a solvent, etc. are added, and the reaction is carried out at a temperature of about 30 to 100°C for about 1 to 30 hours.

As the emulsifier, anionic, nonionic, or anionic-nonionic combinations are used, and in some cases, amphoteric surfactants and cationic surfactants can also be used. Examples of the anionic emulsifier include higher alcohol sulfuric acid ester sodium salt, alkylbenzene sulfonic acid sodium salt, succinic acid sialkyl ester sulfonic acid sodium salt, and alkyldiphenyl ether disulfonic acid sodium salt.

Among these, dodecylbenzene sulfonic acid sodium salt, lauryl sulfate sodium salt, polyoxyethylene alkyl (or alkylphenyl) ether sulfate, and the like are preferably used. Examples of nonionic emulsifiers include polyoxyethylene alkyl ether,
Examples include polyoxyethylene alkyl allyl ether. - Polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, etc. are used for boat fishing. As an amphoteric emulsifier,
Lauryl betaine and the like are suitable.

As the cationic surfactant, alkylpyridinium chloride, alkylammonium chloride, etc. can be used. Furthermore, copolymerizable with the above monomer,
So-called reactive emulsifiers, such as sodium styrene sulfonate, sodium allylalkylsulfonate, etc., may also be used as emulsifiers.

The amount of emulsifier used is usually 0.05 to 100 parts by weight of the vinylidene fluoride polymer particles and monomer mixture.
The amount is about 5 parts by weight.

As the polymerization initiator, for example, water-soluble persulfates, hydrogen peroxide, etc. can be used, and depending on the case, they can be used in combination with a reducing agent.

Examples of the reducing agent include sodium pyrobisulfite, sodium hydrogensulfite, sodium thiosulfate, L-ascorbic acid and its salts, and sodium formaldehyde sulfoxylate. In addition, oil-soluble polymerization initiators such as 2゜2'-azobisisobutyronitrile, 2,2'-azobis-(4-methoxy-2,4
-dimethylvaleronitrile), 2,2'-azobis-2
, 4-dimethylvaleronitrile, l.

1'-Azobis-cyclohexane-1-carbonitrile, benzoyl peroxide, dibutyl peroxide, cumene hydroperoxide, etc. can be used as monomers or dissolved in a solvent. Preferred oil-soluble polymerization initiators include cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, azobisisobutyronitrile, benzoyl peroxide, t-butyl hydroperoxide, 3,5.5 −
) Limethylhexanol peroxide, t-butylperoxy(2-ethylhexanoate), and the like. The amount of polymerization initiator used is 10% of the monomer mixture.
It is 0.1 to 3 parts by weight per 0 parts by weight.

Examples of chain transfer agents include halogenated hydrocarbons (e.g., carbon tetrachloride, chloroform, bromoform, etc.), mercaptans (e.g., n-dodecylmercaptan, t-dodecylmercaptan, n-octylmercaptan, etc.)
, xanthogens (eg, dimethylxanthogen disulfide, diisopropyl xanthogen disulfide, etc.), terpenes (eg, dipentene, terpinolene, etc.), and the like. The amount of chain transfer agent used is approximately 0 to 10 parts by weight = 15 parts by weight per 100 parts by weight of the monomer mixture.

Examples of the chelating agent include glycine, alanine, and ethylenediaminetetraacetic acid, and examples of the pH adjuster include sodium carbonate, potassium carbonate, and sodium hydrogen carbonate. The amount of chelating agent and pH adjuster used was 100% of the monomer mixture, respectively.
0 to 0.1 parts by weight and 0 to 3 parts by weight per part by weight.

As a solvent, small amounts of methyl ethyl ketone, acetone, trichlorotrifluoroethane, methyl isobutyl ketone, dimethyl sulfoxide, toluene, dibutyl phthalate, and methyl can be used within a range that does not impair workability, disaster prevention safety, environmental safety, and manufacturing safety. Pyrrolidone, ethyl acetate, etc. may also be used. The amount of the solvent used is about 0 to 20 parts by weight per 100 parts by weight of the monomer mixture.

Emulsion polymerization using the vinylidene fluoride polymer as seed particles can be carried out using known methods, such as charging the entire amount of the monomer into the reaction system in the presence of the vinylidene fluoride polymer particles, or After charging a portion and reacting in step 6-, the remaining monomer is charged continuously or in parts, the entire monomer is continuously charged, and the vinylidene fluoride polymer is added while the monomers are reacting. This can be carried out by dividing or continuously adding particles.

The average particle diameter of the fluoropolymer particles in the fluoropolymer aqueous dispersion of the present invention is usually about 0.05 to 3 μm, preferably about 0.05 to 1 μm, more preferably 0.1 to 1 μm. It is about 1 μm. Average particle size is 0.05μm
If it is less than this, the viscosity of the aqueous dispersion will increase, making it impossible to obtain an aqueous dispersion with a high solids content, and if the mechanical shearing conditions are severe, coagulation will occur, which is undesirable. On the other hand, 3
If it exceeds μm, the storage stability of the aqueous dispersion will be poor, which is not preferable.

The average particle diameter of the fluoropolymer particles can be adjusted by appropriately selecting the size of the vinylidene fluoride polymer particles.

In addition, the particle diameter of the fluoropolymer in the present invention was measured using a nano-sizer (manufactured by Coulter Co., Ltd.).

The fluoropolymer-containing aqueous dispersion of the present invention contains a water-soluble resin and/or 5 to 70 parts by weight (solid content) of an aqueous dispersion of water-dispersible resin, preferably 10 to 50 parts by weight (solid content) (
total amount of 100 parts by weight).

If the proportion of the aqueous fluoropolymer dispersion exceeds 95 parts by weight (solid content), the durability and other properties of the coating will decrease;
If the amount is less than 0 parts by weight (solid content), chemical resistance etc. will decrease.

As the above-mentioned water-soluble resin, any resin that is generally known as water-soluble can be used. Typical water-soluble resins include N-methylolmelamine resin, alkylated N-methylolmelamine resin, and water-soluble acrylic resin. Examples include resin, urethane resin, epoxy resin, polyester resin, water-based nylon resin, alkyd resin, urea resin, maleated polybutadiene, maleated oil, and the like. Among these, N-methylolmelamine resin, alkylated N-methylolmelamine resin, and water-soluble acrylic resin are preferably used.

The above-mentioned water-dispersible resin is generally one that can form an emulsion, and specific examples include (meth)acrylic emulsion, vinyl acetate emulsion, ethylene-vinyl acetate emulsion, and urethane emulsion. Among these, (meth)acrylic emulsions are preferably used. In addition, when using an emulsion, the amount to be used is determined so that the solid content falls within the above range.

When using the above water-soluble resin and water-dispersible resin together, the ratio of both (water-soluble resin/water-dispersible resin) is 20/80 to
It is preferable to adjust it to a range of 80/20 (parts by weight).

When preparing the fluoropolymer-containing aqueous dispersion of the present invention,
If the water-soluble resin is added as is to the aqueous fluoropolymer dispersion and stirred by an appropriate means, for example, using a stirrer, an aqueous dispersion in which the water-soluble resin is uniformly dissolved can be obtained. It is also possible to dissolve the resin in water in advance and add it as an aqueous solution.

The water-dispersible resin is generally added as an emulsion, but as in the case of water-soluble resins, a uniform aqueous dispersion can be obtained by stirring, for example, using a stirrer.

The fluoropolymer-containing aqueous dispersion can be used as it is, but if necessary, additives such as pigments, pigment dispersants, fillers, and anti-aging agents can be added thereto.

Both fluoropolymer aqueous dispersions and fluoropolymer-containing aqueous dispersions have excellent film-forming properties, weather resistance, transparency,
Because it forms a film with excellent chemical resistance, adhesion to substrates, and mechanical strength, it is suitable for baking or air-drying paints, as well as cationic electrodeposition paints, fiber treatment agents, paper processing agents, floor coating agents,
Carpet backing agents, packing agents, non-adhesive processing agents,
It can also be used as a sealing agent, laminating agent, water- and oil-repellent treatment agent, etc. For example, a fluoropolymer aqueous dispersion is applied to an object to be coated, and the temperature is 100 to 200℃.
If baked for about 0 minutes, a film with excellent durability, chemical resistance, and weather resistance can be obtained. In particular, fluoropolymer-containing dispersions are
Since it has excellent storage stability, it is extremely advantageous in terms of storage and transportation.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that both "parts" and "%" are based on weight.

Example 1 (Production of aqueous fluoropolymer dispersion) A stainless steel autoclave equipped with a stirrer, a thermometer, and a monomer addition pump was equipped with a heater and a nitrogen gas introduction device, and 100 parts of water and fluoride were added to the autoclave. Vinylidene polymer aqueous dispersion (vinylidene fluoride/tetrafluoroethylene/propylene hexafluoride copolymer, average particle size 0.25 μm)
, trade name KYNAR 9301 (manufactured by Pennwalt Co., Ltd.) (uncoagulated latex) 100 parts (solid content) and 0.3 parts of sodium persulfate were charged, and the gas phase was reduced to 1.
The atmosphere was replaced with nitrogen gas for 5 minutes, and the temperature was raised to 75°C.

Next, in a separate container, add 15 parts of acrylic un-butyl, 23 parts of methyl methacrylate, 2 parts of methacrylic acid, 50 parts of water, and 0 parts of sodium alkylbenzenesulfonate as an emulsifier.
．． An emulsified mixture of 2 parts was continuously added to the autoclave over 3 hours. After addition is complete, add 85 to 9
After aging at 5°C for 2 hours, the mixture was cooled, adjusted to pH 118 with aqueous ammonia, and filtered through a 200-mesh wire gauze to obtain an aqueous dispersion of a fluoropolymer.

The average particle size of the polymer particles in the resulting aqueous dispersion was 0.2
It was 7 μm.

The average particle diameter of the polymer particles was measured using a Nano-Sizer manufactured by Coulter.

The minimum film forming temperature (MFT) of the aqueous dispersion was measured using a thermal gradient tester (Rigaku Kogyo Co., Ltd.).

The film-forming property is excellent because of the low MFT.

Further, the aqueous dispersion was poured into a container with a glass frame measuring 15 cm x 10 cm and having a depth of 0.2 cm so that the film thickness after drying was 0.06 cm, and was dried at 50° C. for 24 hours. The obtained dry film is placed in a container 2.
3- It was punched out using a No. 2 boat shape, and the tensile strength, elongation at cutting, and 100% modulus were measured according to JIS-6301. As a result, the tensile strength was 70 kg/cm2, the elongation at cutting was 350%, and the 100% modulus was 45 kg/cm2.
There was.

Transparency was evaluated by visually observing the film as described below.

○: Transparent Δ: Slightly opaque X: Cloudy The film was visually inspected for the presence or absence of cracks.

The results are shown in Table 1.

Comparative Example 1 The same test as in Example 1 was conducted using the same vinylidene fluoride polymer aqueous dispersion as used in Example 1.

The results are shown in Table 1.

It can be seen from the results in Table 1 that the vinylidene fluoride polymer aqueous dispersion is inferior to the fluoropolymer aqueous dispersion of the present invention.

Comparative Example 2 An aqueous dispersion was obtained in the same manner as in Example 1, except that the vinylidene fluoride polymer aqueous dispersion was not used. This aqueous dispersion was adjusted to pH 8 with aqueous ammonia, and then filtered through a 200-mesh wire mesh. The average particle size of the polymer particles was 27 μm.

40 parts of the above aqueous dispersion (solid content) and 100 parts of the same vinylidene fluoride polymer aqueous dispersion as used in Example 1 (
The same tests as in Example 1 were conducted on the resulting aqueous dispersion.

The results are shown in Table 1.

From the results in Table 1, it can be seen that good results cannot be obtained by simply mixing an aqueous polymer dispersion prepared without using seed particles and an aqueous vinylidene fluoride polymer dispersion.

Comparative Example 3 The same procedure as in Example 1 was carried out except that an aqueous dispersion of tetrafluoroethylene homopolymer (average particle size 0.25 μm) was used instead of the vinylidene fluoride polymer aqueous dispersion. An aqueous fluoropolymer dispersion (average particle size of polymer: 0.27 μm) was prepared and tested in the same manner as in Example 1.

The results are shown in Table 1.

From the results in Table 1, it can be seen that even if a fluorine-containing polymer other than vinylidene fluoride-based polymer is used, the object of the present invention cannot be achieved due to poor transparency.

(Margin below) Unable to film continuously.

Examples 2 to 8 Fluoropolymer aqueous dispersions were prepared in the same manner as in Example 1 except that the type and amount of monomers were changed as shown in Table 2. Tested in the same manner.

The results are shown in Table 3.

The polymer particle diameters of each fluoropolymer aqueous dispersion are shown in Table 2. (Left below) -30 Example 9 100 parts (solid content) of the aqueous fluoropolymer dispersion obtained in Example 1 was added with titanium oxide (trade name, Tybake R930, 6 Hara Sangyo Co., Ltd.) as a filler. ), 50 parts of polycarboxylic acid sodium salt (trade name, 5N-D) as a dispersant.
I 5PER5ANT5044, manufactured by San Nopco) 2 parts, 1 part ethylene glycol as antifreeze agent, preservative (
Product name, 5N-215, manufactured by San Nopco Co., Ltd.) 0.05 part, antifoaming agent (product name, FOAMAS TER-AP,
After adding 0.5 parts of San Nobuco Co., Ltd.) and 2 parts of 2-amino-2-methyl-1-propatool and adjusting the solids content to 60% with water, hydroxyethylcellulose (manufactured by San Nobuco) was added as a thickener. A-5000 (manufactured by Fuji Chemical Co., Ltd.) was used to adjust the viscosity of the paint to 4000 cps.

After thorough mixing using a disper stirrer, the mixture was transferred to a vacuum defoaming machine for defoaming.

An iron plate (JIS-G3141.5pc CD plate, 0.8
The film was coated onto a surface (70 x 150 mm) using an airless spray gun so that the coating film after drying was 200 μm. The coated iron plate was dried at 150° C. for 15 minutes.

The above coated iron plate was subjected to the following tests.

(b) Gloss retention rate (%) with respect to the initial gloss value after 1000 hours in a weather resistant fade meter (manufactured by Suga Test Instruments Co., Ltd.)
The weather resistance was evaluated based on the following criteria.

Gloss retention rate 0: 100-80 △: 79-40 ×: 39 or less (b) Cross-cut the adhesive coating surface (2 mm squares 10 x 10 pieces)
After that, the adhesive tape was subjected to a peel test using Chiban Co., Ltd.). Adhesion was evaluated according to the following criteria.

Remaining number on cut surface 0: 100-80 △: 79-40 ℃, 24 hours).

(d) Volatile oil resistance No. 2 volatile oil was used in accordance with J Is-5400. N was tested.

(e) Acid resistance J Is-5400 using 1% sulfuric acid solution 1. N
(20±1°C, 8 hours).

The results are shown in Table 4.

The aqueous dispersion obtained in Example 7.8 (A) was evaluated in the same manner as above, and the results are shown in Table 4.

Comparative Examples 4 to 6 In Example 9, the fluoropolymer aqueous dispersion of Comparative Example 1 (Comparative Example 4) was used instead of the fluoropolymer aqueous dispersion;
A mixture of the aqueous dispersion of Comparative Example 2 (Comparative Example 5) and an aqueous dispersion of tetratonized ethylene homopolymer of Comparative Example 3 (
A paint was prepared in the same manner as in Example 9, except that Comparative Example 6) was not used, and it was tested in the same manner as in Example 9.

The results are shown in Table 4.

From the results in Table 4, it is understood that none of the paints listed in "2" can achieve the object of the present invention.

Examples 10 to 11 In Example 9, instead of the vinylidene fluoride polymer aqueous dispersion, latex of vinylidene fluoride homopolymer (trade name, KYNAR 500 (manufactured by Pennwalt Co., Ltd.) before coagulation was used) ) (Example 10) and vinylidene fluoride/tetrafluoroethylene copolymer (trade name, latex before coagulation of KYNAR 7201 (manufactured by Pennwalt Co., Ltd.)) (Example 11). A paint was prepared in the same manner as in Example 9, and tested in the same manner as in Example 9. Note that the average particle diameter of the polymers was 0.27 μm in all cases.

The results are shown in Table 4. (Left below) 33- 34- Comparative Examples 7 to 10 Aqueous dispersions were prepared in the same manner as in Example 1, except that the type and amount of monomers were changed as shown in Table 5. Thereafter, a paint was prepared in the same manner as in Example 9, and its performance was evaluated.

The results are shown in Table 6.

From the results in Table 6, if the total amount of monomers is less than 5 parts by weight per 100 parts by weight of the vinylidene fluoride polymer particles, the adhesion will be poor, while if it exceeds 95 parts by weight, the weather resistance and chemical resistance will be poor. That is understood.

(Leaving space below) Table 6 Example 12 (Production of aqueous fluoropolymer dispersion) In the same autoclave as used in Example 1, add 170 parts of water and add the same aqueous vinylidene fluoride polymer dispersion as used in Example 1. 100 parts of liquid (solid content) and 0.3 parts of sodium persulfate were charged, the gas phase was replaced with nitrogen gas for 15 minutes, and the temperature was raised to 75°C.

Next, in a separate container, 43 parts of n-butyl acrylate, 47 parts of methyl methacrylate, 5 parts of methacrylic acid, 50 parts of water, and 0.7 parts of sodium alkylbenzenesulfonate as an emulsifier were emulsified and mixed, and the mixture was placed in the autoclave. The introduction was carried out continuously over a period of 5 hours.

After the introduction, the mixture was further aged at 85 to 95°C for 2 hours,
After cooling and adjusting to pl-18 with ammonia water,
The mixture was filtered through a 00 mesh wire mesh to obtain an aqueous fluoropolymer dispersion.

The average particle size of the polymer particles in this aqueous dispersion was measured using the same device as used in Example 1, and was found to be 0.29μ.
It was m.

(Preparation of fluoropolymer-containing aqueous dispersion) - Opening - To 80 parts (solid content) of the above fluoropolymer aqueous dispersion, N-methylolmelamine (trade name, M-3, Sumitomo 3M Ltd.) was added. A fluoropolymer-containing aqueous dispersion was obtained.

The storage stability of this fluoropolymer-containing aqueous dispersion was evaluated by the following method.

The results are shown in Table 8.

The aqueous dispersion containing the pentafluoropolymer was allowed to stand at room temperature, and sedimentation or separation of the dispersion was visually determined.

O: No abnormality for 2 months △: No abnormality for 1 month ×: Sedimentation and separation of the dispersion occurred within 1 month Next, the characteristics of the film obtained using the above fluoropolymer-containing aqueous dispersion were evaluated. In order to do this, first, a paint was prepared using this fluoropolymer-containing aqueous dispersion.

(Preparation of paint) 100 parts of the above fluoropolymer-containing aqueous dispersion (solid content)
After adding the same filler, powder, antifreeze, antifoaming agent and 2-amino-2-methyl-1-propanol as used in Example 1 in the same amounts as in Example 1, Water was added to adjust the solids content to 50%. The same thickener used in Example was then added to adjust the paint viscosity to 2000 cps. The mixture was thoroughly mixed using a disper stirrer, and then transferred to a vacuum defoaming machine for defoaming.

The resulting paint was degreased with xylene and an alkaline detergent and applied to the same iron plate used in Example 1 using an air spray gun so that the coating thickness after drying was 100 μm. The coated iron plate was dried at 150° C. for 15 minutes.

The following tests were conducted on the obtained painted iron plate.

The results are shown in Table 8.

Nuts (M-6) are passed through a vinyl pipe from a height of 2 meters.
) was dropped onto the coating film at an angle of 60 degrees, the weight of the nut when the iron plate was exposed was determined, and the durability was evaluated according to the following criteria.

Q: 39kg or more △: 8 on 11-29 x: 10kg or less Measured according to JIS-5400.6-14.

Resistance to 1" zL bleaching was measured according to JIS-5400 (using a 5% aqueous sodium carbonate solution, temperature 40±2°C for 16 hours).

It was measured according to 5400 on Ku1do Dodo J Is- (using No. 2 volatile oil).

Comparative Example 11 The same vinylidene fluoride polymer aqueous dispersion used as seed particles in Example 12 and N-methylolmelamine were mixed in the same manner as in Example 12 to prepare a fluoropolymer aqueous dispersion. did.

Example] In the same manner as in 2, the storage stability of the above fluoropolymer-containing aqueous dispersion was investigated, and a paint was prepared using it.
The properties of the resulting coating film were evaluated.

2 The results are shown in Table 8.

From the results in Table 8, it is clear that when the vinylidene fluoride polymer aqueous dispersion as seed particles is used as it is instead of the fluoropolymer-containing aqueous dispersion obtained by seed polymerization, the resulting fluoropolymer It can be seen that the aqueous dispersion contained therein has poor storage stability and the durability of the coating film is also low.

Example 13 In Example 12, a self-crosslinking acrylic emulsion (trade name, AE-8) was used instead of N-methylolmelamine.
Example 1 except that 15, manufactured by Japan Synthetic Rubber Co., Ltd.) was used.
A fluoropolymer-containing aqueous dispersion and paint were prepared in the same manner as in Example 12, and the storage stability and coating film were evaluated.
I did it in the same way.

The results are shown in Table 8.

Examples 14 to 16 The same procedure was carried out as in Example 12, except that the type and amount of monomer used, and the amount of vinylidene fluoride polymer aqueous dispersion used as seed particles were changed as shown in Table 7. An aqueous fluoropolymer-containing dispersion and a paint were prepared in the same manner as in Example 12, and the storage stability and coating film were evaluated.

The results are shown in Table 8.

Comparative Examples 12 to 13 Fluoropolymer aqueous dispersions and paints were prepared in the same manner as in Example 12, except that the amount of N-methylolmelamine was changed as shown in Table 7, and storage stability was achieved. The properties and coating film were evaluated.

The results are shown in Table 8.

From the results in Table 8, it can be seen that when the amount of N-methylolmelamine added is outside the range specified in the present invention, the durability and hardness of the coating film are poor, and the alkali resistance of the coating film is also poor.

Comparative Examples 14-15 Example 12 except that the type and amount of monomer used and the amount of vinylidene fluoride polymer aqueous dispersion used as sheet particles were changed as shown in Table 7. A fluoropolymer-containing aqueous dispersion and paint were prepared in the same manner as above, and the storage stability and coating film were evaluated.

The results are shown in Table 8.

From the results in Table 7, it can be seen that when the amount of vinylidene fluoride polymer particles used is outside the range specified in the present invention, the durability of the coating film is poor, and the volatile oil resistance and alkali resistance of the coating film are also poor.

Comparative Examples 16 to 17 In Example 12, tetrafluoroethylene polymer particles (trade name, AD-1, manufactured by Asahi Glass Co., Ltd.) (Comparative Example 1) were used instead of vinylidene fluoride polymer particles as seed particles.
6), or tetrafluoroethylene/hexafluoropropylene copolymer particles (trade name, ND-1, manufactured by Daikin Corporation) (
A fluoropolymer-containing aqueous dispersion and paint were prepared in the same manner as in Example 12, except that Comparative Example 17) was used, and the storage stability and coating film were evaluated.

The results are shown in Table 8.

From the results in Table 8, it can be seen that when fluoropolymer particles other than vinylidene fluoride polymer particles are used as seed particles, the volatile oil resistance and alkali resistance are inferior.

(Left below) Comparative Example 18 600g of water in a stainless steel autoclave with an internal volume of 12,
2 g of di-n-propyl peroxycarbonate and 0.68 g of methylcellulose were charged, and after evacuation, 200 g of vinylidene fluoride was introduced from a vinylidene fluoride monomer cylinder through a conduit. Next, autoclave at 25℃
When placed in a constant temperature water bath and stirred at a speed of 350 rpm, 20
The internal pressure decreased from 40 kg/cm2 to 18 kg/cm2 over time. Thereafter, unreacted monomers were distilled off under reduced pressure, and the gas phase was replaced with nitrogen gas. At this time, the solid content of the contents was 18%, and it was calculated that 130 g of polyvinylidene fluoride was obtained.

Sodium persulfate 0.39g with internal temperature of 85-95℃
Add n-butyl acrylate and mix in a separate container 19.
58, 29.9 g of methyl methacrylate and 2.6 g of methacrylic acid (per 100 parts of polyvinylidene fluoride,
15 parts, 23 parts and 2 parts, respectively) were added continuously over a period of 3 hours. 8 more after addition
After aging at 5 to 95°C for 2 hours, it was cooled and adjusted to pl-18 with aqueous ammonia.

When looking at the resulting dispersion using an optical microscope, the average particle size was approximately 50.
It was μm.

This aqueous dispersion was evaluated in the same manner as in Examples 1 and 9, and the results are shown below.

Film-forming cracks: Many (unable to form a continuous film) Transparency △ Minimum film-forming temperature: 120°C Physical properties: Tensile strength: 15 kg/cm2 Elongation when cut
100% 100% Modulus 7 kg/cm2 Paint film performance Weather resistance △ Adhesion × Alkali resistance Slightly blistered Volatile oil resistance Slightly blistered Acid resistance Slightly blistered Based on the above results, seeded with polyvinylidene fluoride particles obtained by suspension polymerization It can be seen that when the particles are used, the aqueous fluoropolymer dispersion of the present invention cannot be obtained.

(Effects of the Invention) The aqueous fluoropolymer dispersion of the present invention has excellent film formability, transparency, and adhesion to substrates without impairing the excellent heat resistance and weather resistance inherent to fluoropolymer. properties have been significantly improved.

As described above, the fluoropolymer-containing aqueous dispersion of the present invention has excellent film-forming properties and forms a film with excellent transparency, weather resistance, adhesion to substrates, chemical resistance, mechanical strength, etc. Therefore, in addition to various paints, it can be used as a fiber treatment material, paper processing material, floor coating material, etc.

Claims (2)

[Claims] (1) In the presence of 100 parts by weight of vinylidene fluoride polymer particles, an acrylic acid alkyl ester whose alkyl group has 1 to 18 carbon atoms and/or an alkyl group whose carbon number is 1
-18 methacrylic acid alkyl esters, and optionally 5 to 95 parts by weight of a monomer mixture containing an ethylenically unsaturated compound copolymerizable with these monomers, obtained by emulsion polymerization in an aqueous medium. , and the average particle diameter of the polymer is 0
．． An aqueous fluoropolymer dispersion having a particle diameter of 05 to 3 μm. (2) Fluoropolymer aqueous dispersion 95~ of claim (1)
30 parts by weight (solid content), and 5 to 70 parts by weight (solid content) of an aqueous dispersion of water-soluble resin and/or water-dispersible resin.
A fluoropolymer-containing aqueous dispersion characterized by comprising: