JPH051256A - Fluorinated coating composition, and production of hydroxylated fluoroolefin copolymer - Google Patents

Abstract

PURPOSE:To provide a fluorinated coating compsn. which is excellent in storage stability, does not gel nor exhibit a remarkable increase in dispersion ratio, and can be produced with a high reproducibility. CONSTITUTION:A fluorinated coating compsn. which is prepd. by compounding a hydroxylated fluoroolefin copolymer as the major component with an ammonium carboxylate and/or an alkali metal carboxylate; and a process for producing a fluorinated coating resin by radical-polymerizing a monomer mixture consisting essentially of a fluoroolefin and a hydroxylated vinyl monomer in the presence of an ammonium carboxylate and/or an alkali metal carboxylate, both free from a polymerizable double bond.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine coating composition and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, fluorine-containing copolymers are widely used in many fields because they are extremely excellent in heat resistance, mechanical properties, chemical resistance, weather resistance and the like. One of its uses is as a coating film-forming component of paints, and as a fluorine-containing copolymer having a hydroxyl group and soluble in an organic solvent, which is particularly useful for paints, for example, JP-A-57-34107 can be used. No. 61-275311
JP-A-61-157609 and JP-A-62-1742.
No. 13, JP-A No. 63-182312, and the like, copolymers of a fluoroolefin and a hydroxyl group-containing vinyl monomer copolymerizable therewith are known.

However, these hydroxyl group-containing fluoroolefin copolymers have a problem of poor storage stability, such as high molecular weight or gelation over time.
As a method for solving this problem, for example, Japanese Patent Publication No. 63-
Although a method of adding a specific tertiary amine has been proposed, as is seen in Japanese Patent No. 2305, etc., this method not only causes significant coloring of the resin but also causes significant coloring over time when formed into a coating film. It has drawbacks.

Furthermore, when producing such a fluoroolefin copolymer containing a hydroxyl group, the amount of the hydroxyl group-containing vinyl monomer used is increased, the non-volatile content of the polymer is increased, and the like.
Alternatively, if the molecular weight of the copolymer is increased, gelation may occur during the polymerization, or the dispersion ratio (ratio of the weight average molecular weight and the number average molecular weight) of the produced copolymer may be significantly increased. There is also a problem that it is not possible to manufacture the coalescence with good reproducibility. As a method for solving this problem, a method for producing a hydroxyl group-containing fluoroolefin copolymer in the presence of amines has been proposed as disclosed in, for example, JP-A-62-292813, and such amines have been proposed. Polymerization in the presence has the major drawback that the coloration during polymerization is significant.

[0005]

DISCLOSURE OF THE INVENTION The present invention has solved the above-mentioned problems of the prior art, does not cause gelation during polymerization,
Further, the present invention has been made for the purpose of providing a composition for a fluorine-based coating material containing a fluoroolefin copolymer having a hydroxyl group as a main component which is not colored, and a method for producing the same.

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of the above points, the present inventors can solve the above problems by using an ammonium salt of carboxylic acid or an alkali metal salt of carboxylic acid. After finding things, the present invention was completed. That is, the present invention comprises: (1) A fluoroolefin copolymer containing a hydroxyl group as a main component, and further an ammonium salt of carboxylic acid and /
Alternatively, a fluorine-containing coating composition prepared by blending an alkali metal salt of a carboxylic acid, and (2) a monomer mixture containing a fluoroolefin and a vinyl monomer having a hydroxyl group as essential monomer components are polymerizable double. A fluoroolefin copolymer having a hydroxyl group, which is characterized by radical polymerization in the presence of an ammonium salt of a carboxylic acid having no bond and / or an alkali metal salt of a carboxylic acid having no polymerizable double bond. It is a manufacturing method.

The present invention will be described in detail below. The ammonium salt of a carboxylic acid used in the present invention refers to amino acids and compounds containing one or more groups represented by the formula (a) in the molecule, and as an alkali metal salt of a carboxylic acid, A compound having one or more groups represented by the formula (b) in the molecule.

[0008]

[Chemical 1]

Typical examples of the ammonium salt of the carboxylic acid include acetic acid, lactic acid, propionic acid, capric acid, pivalic acid, 2-ethylhexanoic acid, lauric acid, stearic acid, oxalic acid, succinic acid, and adipine. Acids, carboxylic acids such as glycolic acid and diethylamine, dipropylamine, N-methylethanolamine, diethanolamine, dimethylcyclohexylamine, dimethylethanolamine, triethanolamine, triethylamine, tributylamine, pyrrolidine, piperidine, 1-methylpiperidine, 2, 2, 6,
6-tetramethylpiperidine, 4-hydroxy-2,
2,6,6-Tetramethylpiperidine, and further salts with amines such as tetramethylammonium ion, methyltriethylammonium ion, tetraethylammonium ion, such as glycine, alanine, β-alanine, valine, leucine, isoleucine, serine, Examples thereof include amino acids such as cystine, lysine, phenylalanine, and anthranilic acid.

Representative examples of the alkali metal salts of carboxylic acids include the alkali metal salts of carboxylic acids mentioned above. Among these, salts of carboxylic acids and tertiary amines, and quaternary ammonium salts of carboxylic acids are preferable because they are excellent in compatibility with the fluororesin and are less colored. These may be used alone or in combination of two or more.

A method for producing a fluorine-containing coating composition comprising a fluoroolefin copolymer having a hydroxyl group as a main component and further containing an ammonium salt of a carboxylic acid and / or an alkali metal salt of a carboxylic acid is as follows: The methods (a) and (b) shown in (2) are mentioned. (A) A predetermined amount of an ammonium salt of a carboxylic acid and / or an alkali metal salt of a carboxylic acid is added to a composition for a fluorine-based coating material containing a fluoroolefin copolymer having a hydroxyl group as a main component.

(B) A monomer mixture containing a fluoroolefin and a hydroxyl group-containing vinyl monomer as essential monomer components,
Radical polymerize. During this polymerization, a predetermined amount of an ammonium salt of a carboxylic acid having no polymerizable double bond and / or an alkali metal salt of a carboxylic acid having no polymerizable double bond is present so as not to react with these monomer mixtures. . As the method for producing the resin for fluorine-based coating material of the present invention, the methods (a) and (b) can be arbitrarily selected,
The method (b) is also effective and suitable for preventing gelation during polymerization, and is preferable. However, when the method (b) is applied, it is essential to use the above-mentioned ammonium salt of carboxylic acid and alkali metal salt of carboxylic acid that do not have a double bond.

The amount of the ammonium salt of carboxylic acid and / or the alkali metal salt of carboxylic acid described above is 0. 001 to 10% by weight,
It is preferably 0.005 to 5% by weight. If it is less than 0.001% by weight, gelation occurs during polymerization, and the obtained hydroxyl group-containing fluoroolefin copolymer becomes high in molecular weight with time, which is not preferable. Also, 1
If it exceeds 0% by weight, various physical properties of the coating film may be deteriorated, which is not preferable.

The raw material for the fluoroolefin unit of the hydroxyl-containing fluoroolefin copolymer in the present invention is represented by the formula (c)

[0015]

[Chemical 2]

What is represented by is used. Specific examples of such a vinyl monomer include, for example,

[0017]

[Chemical 3]

Fluoroethylene such as;

[0019]

[Chemical 4]

A fluoropropene system such as;

[0021]

[Chemical 5]

Fluoro-olefin compounds having 4 or more carbon atoms such as
(C ') expression

[0023]

[Chemical 6]

The fluoroethylene compounds and fluoropropene compounds are preferable represented by, in particular tetrafluoroethylene (CF ₂ = CF _2), chlorotrifluoroethylene (CF ₂ = CFCl) and hexafluoropropene (CF ₂ = CFCF ₃₎ is It has good polymerizability and is suitable. These fluoroolefins may be used alone or in combination of two or more.

Further, as the raw material of the hydroxyl group-containing unit,
Formula (d)

[0026]

[Chemical 7]

What is represented by is used. Specific examples of such a hydroxyl group-containing vinyl monomer include, for example, 2-
Hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and 4-hydroxycyclohexyl vinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyallyl vinyl ether and 4-hydroxybutyl allyl ether, 2-hydroxyethyl (meth) acrylate Representative examples are hydroxyl group-containing (meth) acrylates such as 4-hydroxypropyl (meth) acrylate, 2-hydroxyethyl crotonate, hydroxyl group-containing crotonic acid esters such as 4-hydroxypropyl crotonate, and allyl alcohol. However, among these, hydroxyalkyl vinyl ethers are preferable because of their good reactivity with fluoroolefins. These hydroxyl group-containing vinyl monomers may be used alone or in combination of two or more.

The hydroxyl-containing fluoroolefin copolymer according to the present invention requires, in addition to the above-mentioned essential monomer components, other vinyl monomers which can be copolymerized with these essential monomer components. Can be copolymerized accordingly. Examples of such other vinyl monomers include olefins such as ethylene, propylene and isobutylene, haloolefins such as vinyl chloride and vinylidene chloride, vinyl acetate, n-
Vinyl butyrate, vinyl benzoate, pt-butyl vinyl benzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, vinyl laurate, and other carboxylic acid vinyl esters, isopropenyl acetate, isopropenyl propionate. Carboxylic acid isopropenyl esters such as, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, neopentyl vinyl ether, 2-ethylhexyl vinyl ether, octyl vinyl ether and other chain alkyl vinyl ethers, pentafluoroethyl vinyl ether, Fluorovinyl ethers such as 2-perfluorooctylethyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether Cycloalkyl vinyl ethers such as ether, aryl ether, and phenyl vinyl ether, benzyl vinyl ether, pheneticillin aralkyl ether and chilled ether, styrene,
Aromatic vinyl compounds such as vinyltoluene Allyl formate, allyl acetate, allyl butyrate, allyl benzoate, allyl ester such as allyl cyclohexanecarboxylate, allyl cyclohexylpropionate, allyl ethers such as allyl ethyl ether, allyl phenyl ether, butyl (Meth) acrylate, methyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxy-4- (2-methacryloxyethoxy) benzophenone, perfluoromethyl (meth) acrylate, perfluoropropyl ( (Meth) acrylate, perfluoropropyromethyl (meth) acrylate, perfluoromethylmethyl (meth)
Examples thereof include acrylic acid and methacrylic acid esters such as acrylate, 2-perfluorooctylethyl (meth) acrylate, and perfluoroisononylmethyl (meth) acrylate, and acrylamides such as acrylamide and N-methylolacrylamide.

Further, a vinyl monomer having a cyclic hydrocarbon group introduced through a urethane bond, which is disclosed in Japanese Patent Application No. 1-237122, and Japanese Patent Application No. 2-101695. Examples include cyclic vinyl ethers,
When these are used, the resulting fluorine-containing resin is excellent in gloss, hardness, weather resistance and the like, which is preferable. These vinyl monomers may be used alone or in combination of two or more.

In the hydroxyl group-containing fluoroolefin copolymer of the present invention, the ratio of each of the above-mentioned monomer components used from the viewpoint of the yield and weather resistance of the copolymer is fluoroolefin 1
0-80 mol%, hydroxyl group-containing vinyl monomer 2-50 mol%, other copolymerizable vinyl monomer 0-60 mol%, preferably fluoroolefin 20-60 mol%, hydroxyl group-containing vinyl monomer It is controlled to 5 to 30 mol% and other copolymerizable vinyl monomer to 5 to 50 mol%.

The polymerization of the hydroxyl group-containing fluoroolefin copolymer of the present invention is preferably carried out in the presence or absence of a solvent by using a predetermined proportion of a vinyl monomer mixture essentially containing the fluoroolefin and the hydroxyl group-containing vinyl monomer. Is polymerizable 2
Copolymerize in the presence of an ammonium salt of a carboxylic acid having no heavy bond and / or an alkali metal salt of a carboxylic acid having no polymerizable double bond, using a polymerization initiator or ionizing radiation as a polymerization initiation source. It can be done by

As the polymerization initiator, a water-soluble one or an oil-soluble one is appropriately used depending on the type of polymerization or desired. Examples of the oil-soluble initiator include azo compounds such as azobisisobutyronitrile and 2,2′-azobis- (2,4-dimethylvaleronitrile), t-butylperoxypivalate, t-butylperoxyiso. Peroxy ester type peroxides such as butyrate, octanoyl peroxide, diacyl peroxide type peroxides such as lauroyl peroxide, dialkyl peroxydicarbonate type peroxides such as diisopropyl peroxydicarbonate, benzoyl peroxide And the like, such as dialkyl peroxide type peroxides.

The water-soluble polymerization initiator is, for example, a persulfate such as potassium persulfate, hydrogen peroxide, or a redox initiator composed of a combination of these with a reducing agent such as sodium bisulfite and sodium thiosulfate. ,
Inorganic initiators such as those in which a small amount of iron, ferrous salt, silver nitrate, etc. coexist, dibasic acid peroxides such as disuccinic acid peroxide, diglutaric acid peroxide, and monosuccinic acid peroxide, azobi Examples include organic initiators such as perisobutylamidine dibasic acid salt. The amount of these polymerization initiators to be used is appropriately selected depending on the type, the copolymerization reaction conditions, etc., but 0.005 to 5% by weight, preferably 0.05 to the total amount of the monomers usually used.
To 0.5% by weight.

The polymerization method is not particularly limited, and for example, bulk polymerization method, suspension polymerization method, emulsion polymerization method, solution polymerization method and the like can be used, but from the viewpoint of stability of the polymerization reaction operation, etc. Solvents such as lower alkyl-substituted benzenes such as xylene and toluene, esters such as butyl acetate, ketones such as methyl isobutyl ketone, alcohols such as t-butanol, and saturated halogenated hydrocarbons having one or more fluorine atoms are used as a solvent. The solution polymerization method, the emulsion polymerization method in an aqueous medium, the bulk polymerization method that does not require separation from the solvent, and the like are preferably used.

Further, the polymerization system is not particularly limited, and any of batch system, semi-continuous system and continuous system can be used. The reaction temperature in the copolymerization reaction is usually -30.
Within the range of to + 150 ° C, it is appropriately selected depending on the type of the polymerization initiation source and the polymerization medium, and is usually 0 to 100 ° C, preferably 1
It is selected in the range of 0 to 90 ° C. The reaction pressure is not particularly limited, but is selected from the range of normal pressure to 100 kg / cm ² . Further, the copolymerization reaction can be carried out by adding an appropriate chain transfer agent.

The hydroxyl group-containing fluoroolefin copolymer of the present invention has a molecular weight of tetrahydrofuran as a solvent and monodisperse polystyrene of known molecular weight as a standard substance.
The number average molecular weight (Mn) measured by gel permeation chromatography (GPC) method is 500 to 20.
50,000, preferably 2,000 to 100,000, and the glass transition temperature (Tg) is usually -50 to 1.
It is 20 ° C, preferably -10 to 100 ° C.

In the composition of the present invention, the above-mentioned hydroxyl group-containing fluoroolefin copolymer, ammonium salt of carboxylic acid and / or alkali metal salt of carboxylic acid are preferably dissolved or dispersed in an organic solvent. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, alcohols such as n-butanol, esters such as n-butyl acetate, ketones such as methyl isobutyl ketone, glycol ethers such as ethyl cellosolve, Furthermore, various commercially available thinners and the like can be mentioned.

The fluorine-based coating composition of the present invention may be used as it is or as a curing agent capable of reacting with a hydroxyl group, a pigment, a filler, a curing catalyst, a dispersion stabilizer, a viscosity modifier, a leveling agent, an anti-gelling agent, An ultraviolet absorber, other additives for paints, etc. can be blended and used for various purposes such as paints, sealing agents and films.

[0039]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to the embodiments. Molecular weights of various resins: Determined from a polystyrene standard calibration curve using gel permeation chromatography.

Equipment used Equipment: Shimadzu LC-3
A column: Tosoh Corp. TSKgel G-5000 HXL TSKgel G-4000 HXL TSKgel G-2000 HXL Detector: Shimadzu RID-6A Data processing: Shimadzu C-R4A Carrier: Tetrahydrofuran hydroxyl value; JIS K-0070 Measured. Number of colors (APHA color); measured according to ASTM D1209.

[0041]

Example 1 The inside of a stainless steel autoclave equipped with a stirrer having an internal volume of 1 liter was replaced with nitrogen gas three times.
Then, 23 g of 4-hydroxybutyl vinyl ether,
80 g of isobutyl vinyl ether, 117 g of chlorotrifluoroethylene, 220 g of xylene, 0.7 g of triethylamine salt of acetic acid and 1.7 g of t-butylperoxypivalate as an initiator were charged, and polymerization was carried out at 67 ° C. for 8 hours. The produced copolymer solution has a nonvolatile content (N
V) 49.3%, number average molecular weight is 10,200,
The hydroxyl value was 51 mgKOH / g, and the APHA color score was 60.

The obtained copolymer solution was placed in a glass bottle, sealed, and kept at 50 ° C. to trace the change in viscosity.
The initial viscosity remained after months.

[0043]

Example 2 An autoclave with an internal volume of 1 liter and made of a stainless steel and equipped with a stirrer was charged with 7.7 g of potassium carbonate, and the inside of the autoclave was replaced with nitrogen gas three times. Then, 23 g of 4-hydroxybutyl vinyl ether, 80 g of isobutyl vinyl ether, 117 g of chlorotrifluoroethylene, 220 g of xylene, and 1.7 g of t-butylperoxypivalate as an initiator were charged, and 6
Polymerization was performed at 7 ° C. for 8 hours. Potassium carbonate was removed by filtration from the produced copolymer solution, and the nonvolatile content (NV) of 50.
1%, number average molecular weight 11,200, hydroxyl value 51 mgK
A hydroxyl group-containing fluoroolefin copolymer solution having an OH / g and APHA color rating of 20 was obtained. 0.3 g of acetic acid triethylamine salt was added to 100 g of the obtained copolymer solution.
Stir well after adding to a glass bottle and stir well.
When the viscosity change was traced while keeping the temperature at 0 ° C, the initial viscosity remained the same even after 1 month.

[0044]

Example 3 The inside of an autoclave with an internal volume of 1 liter and made of a stainless steel and equipped with a stirrer was replaced with nitrogen gas three times.
Then, 23 g of 4-hydroxybutyl vinyl ether,
21,3-Dihydrofuran 21 g, isobutyl vinyl ether 50 g, chlorotrifluoroethylene 117 g, butyl acetate 211 g, succinic acid-bis (2,2,6,6-
2.1 g of tetramethylpiperidine) salt and 1.7 g of t-butylperoxypivalate as an initiator were charged, and 6
Polymerization was performed at 7 ° C. for 8 hours. The resulting copolymer solution had a nonvolatile content (NV) of 49.8% and a number average molecular weight of 9,
200, hydroxyl value is 53 mgKOH / g, APH
The A color score was 20.

The obtained copolymer solution was placed in a glass bottle, sealed, and then kept at 50 ° C. to trace the change in viscosity.
The initial viscosity remained after months.

[0046]

[Example 4] 7.7 g of potassium carbonate was charged into an autoclave made of stainless steel and having an internal volume of 1 liter, and the inside of the autoclave was replaced with nitrogen gas three times. Then, 28 g of 4-hydroxybutyl vinyl ether, 63 g of a reaction product of cyclohexyl isocyanate and 4-hydroxybutyl vinyl ether, 50 g of isobutyl vinyl ether, 117 g of chlorotrifluoroethylene, 258 g of xylene, and t-butyl peroxypivalate as an initiator 1. 7 g was charged and polymerization was performed at 67 ° C. for 8 hours. Potassium carbonate was removed from the resulting copolymer solution by filtration to obtain a non-volatile content (NV) of 50.1%, a number average molecular weight of 12,200, a hydroxyl value of 51 mgKOH / g, and HAZE.
A hydroxyl group-containing fluoroolefin copolymer solution of N color 30 was obtained.

To 100 g of the obtained copolymer solution, 0.5 g of tetraethylammonium salt of 2-ethylhexanoic acid was added, and the mixture was sufficiently stirred, placed in a glass bottle and sealed, and then at 50 ° C.
When the viscosity change was traced by keeping the value at 1, the initial viscosity remained the same even after 1 month.

[0048]

Comparative Example 1 When a reaction was carried out in the same manner as in Example 1 except that 0.7 g of a triethylamine salt of acetic acid was not used, a jelly-like gel product was formed.

[0049]

Comparative Example 2 The copolymer solution obtained in Example 2 was placed in a glass bottle and sealed without adding an acetic acid-triethylamine salt, and then the temperature was kept at 50 ° C. and the change in viscosity was traced. did.

[0050]

Comparative Example 3 The reaction was carried out in the same manner as in Example 1 except that 0.4 g of triethylamine was used instead of 0.7 g of acetic acid-triethylamine salt, and the resulting copolymer solution was markedly colored (APHA color The score is 300).

[0051]

[Reference Example 1] The hydroxyl group-containing fluoroolefin copolymer solution obtained in Example 1 was used as the main agent, and "Duranate TPA" (manufactured by Asahi Kasei Kogyo Co., Ltd.) was used as a curing agent in NCO / O.
After blending so that H = 1/1, xylene was used as a thinner and Ford cup # 4 was adjusted to 15 seconds for coating. Bake the obtained coating film at 120 ° C. for 1 hour,
Incidence (light receiving) angle based on JIS K-5400; 6
When the gloss of the coating film was measured at 0 °, a cured coating film having a good appearance with a gloss of 85% was obtained. When this coating film was exposed to a sunshine weather meter for 3000 hours, there was almost no deterioration in gloss and good weather resistance was exhibited.

[0052]

As is clear from the above results, the fluoroolefin copolymer containing a hydroxyl group according to the present invention is contained as a main component, and further an ammonium salt of carboxylic acid and / or an alkali metal salt of carboxylic acid is contained. The fluorine-based coating composition obtained from the above shows good storage stability. Also,
A fluoroolefin having a hydroxyl group is obtained by radical polymerization of a monomer mixture containing a fluoroolefin and a vinyl monomer having a hydroxyl group as essential components in the presence of an ammonium salt of a carboxylic acid and / or an alkali metal salt of a carboxylic acid. The method for producing a polymer effectively suppresses gelation during polymerization and a significantly large dispersion ratio (ratio between weight average molecular weight and number average molecular weight) of the produced copolymer.

Therefore, according to the method of the present invention, there is provided a hydroxyl group-containing fluoroolefin copolymer having excellent weather resistance which can be used in various applications such as paints, sealing agents and films.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09D 129/10 PFP 6904-4J

Claims (2)

[Claims] 1. A fluorine-based coating composition comprising a fluoroolefin copolymer having a hydroxyl group as a main component and further containing an ammonium salt of a carboxylic acid and / or an alkali metal salt of a carboxylic acid. 2. An ammonium salt of a carboxylic acid which does not have a polymerizable double bond, and / or a monomer mixture containing a fluoroolefin and a vinyl monomer having a hydroxyl group as essential monomer components.
Alternatively, a method for producing a fluoroolefin copolymer having a hydroxyl group, characterized by radically polymerizing in the presence of an alkali metal salt of a carboxylic acid having no polymerizable double bond.