JPH11171933A - Fluorine-containing copolymer and curing composition containing the copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject copolymer having excellent compatibility with acrylic resin, storage stability, etc., by including a specific fluoroolefin, a specific ester and a specific vinyl ether and adjusting the number-average molecular weight to a specific level. SOLUTION: The objective copolymer is produced by including (A) 40-90 mol.% of a fluoroolefin of the formula I (X is F or H; Y is H, Cl, F or CF3 ) (e.g. vinylidene fluoride), (B) 1-30 mol.% of a cyclohexyl acrylate of the formula II (R<1> is H or methyl) (e.g. cyclohexyl methacrylate), (C) 1-30 mol.% of an OH-containing vinyl ether of the formula III (R<2> is a 2-5C alkylene or cyclohexyl) (e.g. hydroxybutyl vinyl ether) and (D) 0-20 mol.% of other copolymerizable monomer (e.g. ethyl vinyl ether) and adjusting the number- average molecular weight to 1,000-50,000. A curing composition is produced by including the copolymer in combination with an acrylic copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing copolymer having a functional group and a curing composition comprising the copolymer and an acrylic copolymer. More specifically, it contains a copolymer comprising a fluoroolefin, a cyclohexyl group-containing acrylate ester, and a hydroxyl group-containing vinyl ether (hereinafter, referred to as a fluorine-containing copolymer of the present invention) and an acrylic copolymer having a functional group. It relates to a curing composition.

[0002]

2. Description of the Related Art Conventionally, a fluorine-containing resin copolymer obtained by polymerizing a fluoroolefin, a hydroxyalkyl vinyl ether or an alkyl vinyl ether has been used as one of the components of a room temperature-curable fluororesin paint which does not require high-temperature baking. (See Japanese Patent Publication No. 60-21686). However, since this copolymer contains vinyl ethers in a total of 40% mol or more in monomer units, the content of fluorine is small and a problem occurs in the stain resistance of the coating film. In addition, when used as a fluororesin paint because of its low fluorine content, the expected properties of the fluororesin paint can be obtained unless a large amount of the fluorine-containing copolymer is blended with respect to the weight ratio of the acrylic resin. There is a problem that can not be done.

[0003]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to obtain a fluorine-containing copolymer having good compatibility with an acrylic copolymer having a functional group. When used as a component of a room temperature-curable fluororesin paint because of its excellent stability and high fluorine content, a room temperature-curable fluorine-containing copolymer that gives excellent coating properties with a small amount of addition was found, and the present invention was developed. It was completed.

[0004]

That is, the present invention provides:
(A) General formula

Embedded image (Wherein X is F or H, and Y is H, Cl, F, CF ₃ ) 40 to 90 mol% of a fluoroolefin represented by the following formula:

Embedded image (Wherein R ¹ is hydrogen or a methyl group) 1 to 30 mol% of acrylic acid cyclohexyl ester, and (C) a general formula:

Embedded image (Wherein, R ² represents an alkylene group having 2 to 5 carbon atoms or a cyclohexyl group) A fluorine copolymer containing 1 to 30 mol% of a hydroxyl group-containing vinyl ether represented by the following formula: It is intended to provide a curing composition containing a polymer.

In the copolymer of the present invention, (A) the fluoroolefin forming the polymerized unit is an olefin having at least two fluorine atoms in the molecule, for example, vinylidene fluoride, tetrafluoroethylene, chlorotrifluoro. Preferred are ethylene, hexafluoropropene, and the like. These fluoroolefins may be used alone or in combination of two or more.

In the copolymer of the present invention, (B) the monomer forming the polymerized unit is represented by the general formula (ii).
Preferable specific examples of such a monomer include, for example, cyclohexyl acrylate, cyclohexyl methacrylate and the like, and cyclohexyl methacrylate is particularly preferable.

In the copolymer of the present invention, specific examples of (C) the hydroxy-containing unsaturated ether forming a polymerized unit include hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, ethylene glycol monoallyl. Examples thereof include ether and cyclohexyl vinyl ether, with hydroxybutyl vinyl ether, hydroxyethyl vinyl ether and cyclohexyl vinyl ether being particularly preferred. Each of these hydroxy-containing unsaturated ethers may be used alone,
Two or more kinds may be used in combination.

The copolymer of the present invention contains the above specific amounts of the polymerized units (A), (B) and (C) as essential components, and has excellent storage stability, is hard, and is resistant to contamination. A coating film having excellent chemical resistance, weather resistance, heat resistance, etc. can be formed. However, in addition to these units, other copolymers may be formed in an amount not exceeding 20 mol% depending on the purpose of use. It can also contain possible monomer units.

Examples of the copolymerizable monomer include alkyl vinyl ethers such as ethyl vinyl ether, butyl vinyl ether and cyclohexyl vinyl ether, olefins such as ethylene and propylene, halo olefins such as vinyl chloride and vinylidene chloride, and vinyl acetate. And carboxylic acid vinyl esters such as n-vinyl butyrate and vinyl versatate.

The copolymer of the present invention contains 40 to 90 mol% of a polymer unit (A) based on a fluoroolefin, 1 to 30 mol% of a polymer unit (B) based on cyclohexyl acrylate or cyclohexyl methacrylate, 1 to 30 polymerized units (C) having a hydroxyl group
Mol%, and other copolymerizable monomers in a proportion of 0 to 20 mol%.

When the proportion of the polymerized unit (A) is less than 40 mol%, when used as a paint base, sufficient stain resistance, chemical resistance and weather resistance cannot be obtained, which is not preferable. On the other hand, if it is more than 90 mol%, the solubility in various solvents is lowered, and it becomes difficult to use it as a paint base.

If the proportion of the polymerized unit (B) is lower than the above, the storage stability of the resin solution is lowered, and the solvent resistance and chemical resistance of the cured coating film are lowered. Is not preferred because the polymerization rate during the polymerization decreases.

If the proportion of the polymerized unit (C) is lower than the above, the curing reaction becomes difficult to occur, and the solvent resistance and chemical resistance of the cured coating film decrease, which is not preferable. Difficult and undesirable.

The copolymer of the present invention can be produced by copolymerizing a predetermined ratio of a monomer mixture using a polymerization initiator in the presence or absence of a solvent. As the polymerization initiator, a water-soluble one or an oil-soluble one is appropriately used depending on the type of polymerization and the kind of solvent used as desired.

As the water-soluble polymerization initiator, for example, a redox reducing agent comprising a persulfate such as potassium persulfate, hydrogen peroxide, or a combination thereof with a reducing agent such as sodium hydrogen sulfite or sodium thiosulfate; , Inorganic initiators in which a small amount of iron, ferrous salt, silver nitrate, and the like coexist, and organic initiators such as dibasic acid salts such as succinic peroxide, diglutaric peroxide, and monosuccinic peroxide. Are used.

Examples of the oil-soluble initiator include peroxyester peroxides such as t-butylperoxyisobutyrate and t-butylperoxyacetate, diisopropylperoxydicarbonate, and dinormal propylperoxydioxide. Dialkyl peroxydicarbonate such as carbonate, benzoyl peroxide, azobisisobutyronitrile and the like are used.

The amount of these polymerization initiators used is appropriately selected according to the type thereof, copolymerization reaction conditions, etc., but is 0.005 to 5% by weight, preferably 0.1 to 5% by weight, based on the total amount of the monomers. ~ 1%.

The polymerization method is not particularly limited. For example, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method and the like can be used, but ketones such as methyl ethyl ketone and esters such as ethyl acetate can be used. , Saturated halogenated hydrocarbons having one or more fluorine atoms as a solvent, a solution polymerization method, an emulsion polymerization method in an aqueous medium, and the like are preferably used.

When the copolymerization is carried out in an aqueous medium, a suspending agent or an emulsifier is usually used as a dispersion stabilizer, and a basic buffer is added so that the pH value of the reaction solution during the polymerization is preferably 4 or more. Is desirably 6 or more.

The reaction temperature in the copolymerization reaction is usually-
It is appropriately selected depending on the type of the polymerization initiator and the polymerization medium within a range of 30 ° C to 150 ° C. For example, when copolymerization is performed in an aqueous medium, it is usually 0 to 100 ° C, preferably 10 to 9 ° C.
It is selected in the range of 0 ° C. The reaction pressure is not particularly limited, but is usually selected in the range of 1 to 100 kg / cm ² , preferably 1 to 60 kg / cm ² . Further, the copolymerization reaction can be carried out by adding an appropriate chain transfer agent.

The copolymer of the present invention can be blended with other resins and used as a room temperature curable fluororesin paint. As the resin to be blended, for example, one kind of a (meth) acrylic resin, a (meth) acrylic resin containing styrene, a polyester resin, an alkyd resin, various fluororesins other than the above-mentioned fluorocopolymer of the present invention or Two or more types can be blended, but not limited to these. Of these blendable resins,
Particularly, an acrylic resin is preferable. 5 to 95 parts, preferably 10 to 75 parts, of the copolymer of the present invention in 100 parts by weight of the coating material.
It is good to mix parts.

Examples of the acrylic resin include those conventionally used for paints, and have a curable functional group such as a hydroxyl group, a carboxyl group, an epoxy group, or an amino group at the side chain and / or the terminal of the main chain ( (Meth) acrylate copolymers are preferred. For example, copolymers containing hydroxyethyl (meth) acrylate, 2-hydroxyethyl vinyl ether, (meth) acrylic acid, glycidyl (meth) acrylate, 2-aminoethylprop (meth) acrylate, and the like can be given. Acrydic A-814 and Acridic A as commercially available acrylic copolymers
-810-45 (manufactured by Dainippon Ink and Chemicals, Inc.), Tesloid 4211-46, Tesloid 4212-46
(Manufactured by Hitachi Chemical Co., Ltd.), Dianal LR-6
20, Diamond SS-792 (Mitsubishi Rayon Co., Ltd.)
Manufactured by Hitachi Chemical Co., Ltd.), Hitaloid 3046C, and Hitaloid 3018 (manufactured by Hitachi Chemical Co., Ltd.).

The number average molecular weight of the acrylic resin is from 1,000 to 15,000, preferably 5,000, as measured by GPC.
If it is larger than this, solubility in a solvent tends to decrease, and if it is smaller, a problem tends to occur in weather resistance. The copolymer of the present invention contains a hydroxyl group as a curing site, and is heated by using a melamine curing agent, a urea resin curing agent, a multi-base curing agent, etc., which are used in ordinary thermosetting acrylic paints. Can be cured.

The melamine curing agent includes, for example, butylated melamine, methylated melamine, epoxy-modified melamine, and the like, and those having various degrees of modification are appropriately used according to the application, and the degree of self-condensation can also be appropriately selected. . Examples of the urea resin curing agent include a methylated urea resin and a butylated urea resin. Examples of the polybasic acid curing agent include long-chain aliphatic dicarboxylic acids, aromatic polycarboxylic acids, and acid anhydrides thereof. Things.

Further, blocked polyvalent isocyanates can also be suitably used as a curing agent. When using a melamine curing agent or a urea resin curing agent, curing can be promoted by adding an acidic catalyst.

Furthermore, the copolymer of the present invention can be cured at room temperature using polyvalent isocyanates. Preferred examples of the polyvalent isocyanates include non-yellowing diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate, and adducts thereof, and polyvalent isocyanates having isocyanurates. Among these, polyvalent isocyanates having isocyanurates are preferable. Isocyanates are particularly effective.

When normal temperature curing is performed using isocyanurates, the curing can be promoted by adding a known catalyst such as dibutyltin dilaurate.
When preparing a cold-curable fluororesin paint using the copolymer of the present invention, various solvents can be used, xylene, aromatic hydrocarbons such as toluene, alcohols such as n-butanol, butyl acetate. And esters such as ethyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, glycol ethers such as ethyl cellosolve, various commercially available thinners, and the like. Ethyl acetate, methyl ethyl ketone, toluene, xylene, n- Butanol and the like are particularly preferred, and the content of the fluorine-containing copolymer component in the paint is 5 to 80% by weight, preferably 10 to 80% by weight.
It is preferable to adjust the amount to be 60% by weight.

Mixing of the copolymer of the present invention with a solvent can be carried out using various equipments used for ordinary coating, such as a ball mill, a paint shaker, a sand mill, a three-roll mill, and a kneader. At this time, a pigment, a dispersion stabilizer, a viscosity modifier, a leveling agent, an ultraviolet absorber and the like can be added.

When a heat-curable fluororesin paint is prepared using the copolymer of the present invention, melamine, a urea resin, a polybasic acid or an anhydride thereof, a block polyvalent isocyanate and the like are simultaneously mixed during the above mixing. Then, it is used as a one-pack type fluororesin paint.

On the other hand, when a cold-curable fluororesin paint using non-block polyvalent isocyanates is used, the curing agent component is separately prepared to form a two-pack type fluororesin paint. In this case, the pot life of about 1 to 10 hours is adjusted by adjusting the type and amount of the isocyanate and the catalyst, the copolymer concentration, and the content of the unit based on hydroxylalkyl vinyl ether in the copolymer. And a fluororesin paint which cures at room temperature in several hours to several days to give a coating film having good physical properties.

[0031]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0032]

Example 1 (Production of copolymer) An autoclave with a stainless steel stirrer having an inner volume of 1 L (withstand pressure of 100 kg / cm)
² ) After deaeration, vinylidene fluoride (hereinafter VDF)
11.5.3 g, tetrafluoroethylene (hereinafter abbreviated as TFE) 84.4 g, cyclohexyl methacrylate (hereinafter abbreviated as CHMA) 25.3 g, 4-hydroxybutyl vinyl ether (hereinafter abbreviated as HBVB) 24.
5 g, 400 ml of ethyl acetate, and t-butyl peroxypivalate ("Perbutyl P" manufactured by NOF Corporation)
V ") 1.25 g, and the inner temperature was raised to 60 ° C while stirring. After 20 hours, the stirring was stopped, and the unreacted monomer was discharged to stop the reaction. The autoclave was opened and the reaction solution was taken out. The obtained copolymer was isolated by drying under reduced pressure. The polymer yield was 235 g and the monomer conversion was 94%. The hydroxyl value of the obtained copolymer measured by acetylation with acetic anhydride was 50 mg KOH.
/ G, fluorine content by combustion method is 50 wt%, GP
The number average molecular weight measured in C was 3.5 × 10 ⁴ .

This copolymer was dissolved in ethyl acetate and dissolved in ethyl acetate.
% Ethyl acetate solution. The storage stability and compatibility of the 50% ethyl acetate solution, the transparency of the cured coating film of the copolymer, and the characteristics of the coating film were examined by the following methods. Table 1 shows the results.

[Storage stability] The above 50% ethyl acetate solution was placed in a glass bottle, sealed and kept at 50 ° C., and the viscosity of the solution was examined over time. As a result, no increase in viscosity was observed even after 30 days. Was left.

[Compatibility] Coronate HX (commercial isocyanate: Nippon Polyurethane Industry Co., Ltd.) was added to the above 50% ethyl acetate solution so that the ratio of hydroxyl group / NCO (molar ratio) became 1, and the mixture was applied to a JIS G-3141 steel plate. Applied with an applicator and naturally dried at room temperature for 1 week.
Is visually observed for transparency. A: Colorless and transparent B: Slightly cloudy C: Cloudy A copolymer was similarly produced using the monomers shown in Table 1, and their properties were examined. Table 1 shows the results.

[Adhesion] JIS-K5400 6.1
5 (Goban cellotape test).

[Pencil hardness] JIS-K5400
14 (pencil scratch test).

[Alkali Resistance] The appearance of the coating film after a 24-hour spot test with a 5% aqueous NaOH solution was visually observed. ◎: No abnormality ○: Almost no change △: Slightly affected ×: Involved

[Acid Resistance] 24 with 5% HCl aqueous solution
Visual observation of the appearance of the coating film after the time spot test. ◎: No abnormality ○: Almost no change △: Slightly affected ×: Involved

[Magic removal resistance] The surface of the coating film was painted with oil-based magic (black / red / magic ink), left at room temperature for 72 hours, and ethanol was used as a wiping solvent, and the wiping surface was visually observed. Observation. ◎: No trace at all ○: Very slight trace △: Pretty trace ×: Complete trace

[Solvent resistance] Acetone was dropped on the coating film, and coated with a watch glass for 24 hours, and the coating film surface was visually observed. ◎: No abnormality ○: Almost no change △: Slightly affected ×: Involved

[0042]

Example 2 (Preparation of Cured Composition) To 10 g of the 50% ethyl acetate solution obtained in Example 1, 1 g of Cymel 350 (commercially available melamine: manufactured by Mitsui Cytec Co., Ltd.) was added to prepare a cured composition. . This composition was prepared according to JIS G-3141.
It was applied on a steel plate by an applicator and heat-treated at 140 ° C. for 1 hour to obtain a coating film having a thickness of 10 μm. The characteristics were examined in the same manner as in Example 1, and the results are shown in Table 1.

[0043]

[Comparative Example 1] After degassing in a stainless steel autoclave having an internal volume of 1 L and having a stirrer, 31.4 g of VDF and TF
E19.8 g, CHMA 164.8 g, HBVE34.
1 g, ethyl acetate 400 ml, and t-butyl peroxypivalate [Nippon Yushi Co., Ltd. product "Perbutyl P
V "], and the internal temperature was raised to 60 ° C while stirring. After 15 hours, stirring was stopped, and unreacted monomers were released to stop the reaction. The autoclave was opened and the reaction solution was taken out. The resulting copolymer was isolated by liquid drying. The copolymer yield was 183 g and the monomer conversion was 73%. The hydroxyl value of the obtained polymer measured by the acetylation method using acetic anhydride was 90 mg KO.
H / g, fluorine content by combustion method is 14 wt%, G
The number average molecular weight measured by PC was 3 × 10 ⁴ .

The polymer was dissolved in ethyl acetate and dissolved in ethyl acetate.
% Ethyl acetate solution. The storage stability and compatibility of the 50% ethyl acetate solution, the transparency of the cured coating film of the copolymer, and the characteristics of the coating film were examined in the same manner as in Example 1. Table 1 shows the results
Shown in Copolymers were similarly produced using the monomers shown in Table 1, and their properties were examined. Table 1 shows the results.

[0045]

Example 3 Using the monomers shown in Table 2, a fluorine-containing copolymer was obtained in the same manner as in Example 1. The obtained copolymer and acrylic resin were mixed at the ratio (in terms of solid content) shown in Table 2,
A 50% ethyl acetate solution was obtained. In Table 2, the storage stability of the mixture, compatibility with the acrylic resin, transparency of the cured coating film of the mixture, and characteristics of the coating film were examined by the following methods. Table 2 shows the results.

[Storage Stability] The above 50% mixed ethyl acetate solution was put in a glass bottle, sealed and kept at 50 ° C., and the change in solution viscosity was examined over time. After 30 days, no increase in viscosity was observed. Was left.

[Compatibility] Coronate HX [commercial isocyanate: Nippon Polyurethane Industry Co., Ltd.] was added to the above 50% mixed solution so that the hydroxyl group / NCO (molar ratio) became 1, and an applicator was applied on a JIS G-3141 steel plate. And dried naturally at room temperature for one week, and the transparency of the 10 μm-thick coating film is visually observed. A: Colorless and transparent B: Slightly cloudy C: Cloudy The film properties were examined in the same manner as in Example 1. Table 2 shows the results
Shown in

[0048]

Example 4 (Preparation of cured composition) Example 3 Obtained 5
To 10 g of a 0% mixed ethyl acetate solution, 1 g of Cymel 350 (commercially available melamine: manufactured by Mitsui Cytec Co., Ltd.) was added to prepare a cured composition. This composition was prepared according to JIS G-3141.
It was applied on a steel plate by an applicator and heat-treated at 140 ° C. for 1 hour to obtain a coating film having a thickness of 10 μm. The characteristics were examined in the same manner as in Example 3, and the results are shown in Table 2.

[0049]

Comparative Example 2 After degassing in a 1 L stainless steel autoclave with a stirrer, 144.4 g of chlorotrifluoroethylene (hereinafter abbreviated as CTFE), 62.5 g of ethyl vinyl ether (hereinafter abbreviated as EVE), HBVE
43.1 g, 400 ml of ethyl acetate, and 1.25 g of t-butyl peroxypivalate [“Perbutyl PV” manufactured by NOF Corporation] were added, and the internal temperature was increased to 60 ° C. while stirring.
The temperature rose. After 20 hours, the stirring was stopped, and the unreacted monomer was discharged to stop the reaction. The autoclave was opened and the reaction solution was taken out. The resulting copolymer was isolated by liquid drying. The copolymer yield was 228 g and the monomer conversion was 92%. The hydroxyl value of the obtained copolymer measured by acetylation with acetic anhydride was 91 mgK.
OH / g, fluorine content by combustion method is 26 wt%,
The number average molecular weight measured by GPC was 3.5 × 10 ³ .

The obtained copolymer and a commercially available acrylic resin [Acridic A-814: manufactured by Dainippon Ink and Chemicals, Inc.] were mixed at the ratio shown in Table 2 to obtain a 50% ethyl acetate solution. The coating film properties were examined in the same manner as in Example 4. Table 2 shows the results.

[Table 1]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 216: 14)

Claims (3)

[Claims] (A) General formula (1) (Wherein X is F or H, and Y is H, Cl, F, CF ₃ ) 40 to 90 mol% of a fluoroolefin represented by the general formula (B): (Wherein R ¹ is hydrogen or a methyl group) 1 to 30 mol% of acrylic acid cyclohexyl ester; and (C) a general formula: (Wherein R ² represents an alkylene group having 2 to 5 carbon atoms or a cyclohexyl group) 1 to 30 mol% of a hydroxyl group-containing vinyl ether represented by the following formula: A number average molecular weight of 100 mol.
0 to 50,000 fluorinated copolymer. 2. The fluorinated copolymer according to claim 1, wherein the fluoroolefin is at least one of vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene and hexafluoropropylene. 3. A curing composition comprising the fluorinated copolymer according to claim 1 and an acrylic copolymer.