JPH03217408A - Fluorine-containing polymer - Google Patents

Abstract

PURPOSE:To provide the subject polymer having a specific number-average mol.wt., soluble in organic solvents, thermally curable and giving coating films having excellent lusters and hardness by polymerizing a fluoroolefin with a specific unsaturated group-containing phthalate ester in a specified ratio. CONSTITUTION:The objective polymer having a number-average mol.wt. of 1000-200000, preferably 2000-100000, and having an unsaturated group-remaining rate of 10-50% is prepared by polymerizing monomers giving 10-60mol%, preferably 35-55mol%, of fluoroolefin units (preferably tetrafluoroethylene units) and 5-90mol%, preferably 30-70mol%, of an unsaturated group-containing phthalate eater units of the formula (R is H, methyl; X is fluorine, chlorine, etc.; n is 0-3; m is 0-4) as essential structural units in the presence of a polymerization initiator, ionizing radiation, etc.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a novel fluoropolymer.

More specifically, the present invention relates to a fluoropolymer that is soluble in organic solvents, thermocurable, and has excellent gloss and hardness.

[Prior Art] Fluorine-containing polymers have been widely used in many fields due to their excellent heat resistance, mechanical properties, chemical resistance, and weather resistance. One of its uses is in the coating field. For example, coating materials using tetrafluoroethylene polymers and vinylidene fluoride polymers are known, and these materials have excellent lubricity, non-stick properties, weather resistance, and chemical resistance, so they are used in the chemical industry. , used in fields such as food, architecture, and machinery.

However, the fluorine-containing polymer is insoluble in solvents or soluble only in a limited number of special solvents, so it is usually used as a powder, which inevitably limits its range of use. In recent years, attempts have been made to develop solvent-based coating materials that are soluble in organic solvents.

In order to solubilize a fluoropolymer in an organic solvent, it is necessary to disrupt the crystallinity of the fluoropolymer and internally plasticize it by introducing an appropriate copolymer component. As examples, various polymers have been disclosed so far (Japanese Unexamined Patent Publications Nos. 81-275311 and 61-57).
No. 809, No. 82-174213, No. 83-
182312). However, these polymers have the drawback that only coating films with inferior initial gloss and hardness can be obtained compared to conventional coating materials mainly composed of acrylic resins.

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of conventional fluorine-containing polymers that are soluble in organic solvents. This was done with the aim of providing an excellent fluoropolymer.

[Means for Solving the Problems] As a result of intensive research to develop a fluoropolymer having the above-mentioned preferable properties, the present inventors discovered a specific structure containing a fluoroolefin unit and two unsaturated groups. The inventors have discovered that the object can be achieved by using a fluorine-containing polymer containing units having the following as essential constituent units, each contained in a predetermined proportion, and based on this knowledge, the present invention has been completed.

That is, the present invention provides (A) fluoroolefin unit 1
0 to 60 mol%, (B) general formula (X). [In the formula, R is hydrogen or a methyl group; Unit 5 ~
The present invention provides a fluorine-containing polymer which contains 90 mol% as an essential structural unit and has a number average molecular weight (Mn) of 1000 to 200,000 as measured by gel permeation chromatography. be.

The present invention will be explained in detail below.

In the polymer of the present invention, the fluoroolefin forming the unit (A) is an olefin having at least one fluorine atom in the molecule, and preferably all hydrogen atoms of the olefin are fluorine atoms and other halogen atoms. Examples include perhaloolefins in which atoms are substituted.

Further, from the viewpoint of polymerizability and properties of the resulting polymer, fluoroolefins having 2 or 3 carbon atoms, particularly barhaloolefins, are preferred.

Specific examples of such fluoroolefins include CFH
=CH2, CF2 =CH2, CF2 set CFH%CF2
=CF2, fluoroethylene compounds such as CF2-CFC1, fluorobropene compounds such as CF-2-CFCF3, and fluoroolefin compounds having 4 or more carbon atoms such as CF2-CFCF2CF. Fluoroethylene compounds and fluorobropene compounds are preferred, especially tetrafluoroethylene (
CF2-CF2), chlorotrifluoroethylene (CF
2-CFC I) and hexafluoropropene (C
F2-CFCF3) is preferred. These fluoroolefins may be used alone or in combination of two or more.

In the polymer of the present invention, the content of units formed from the fluoroolefin needs to be in the range of 10 to 60 mol%, preferably 35 to 55 mol%.

If the content is less than 10 mol %, the properties of the fluoropolymer, such as weather resistance, will be insufficient, and if it exceeds 60 mol %, the solubility in organic solvents and gloss will decrease.

In the polymer of the present invention, the monomer forming the unit (B) is represented by the following general formula.

(X). In the formula, R is hydrogen or a methyl group, X is fluorine, chlorine, bromine, or a hydrocarbon group having 1 to 4 carbon atoms, and n is 0 to 4.
3. m is an integer from O to 4. When two or more hydrogen atoms bonded to the benzene nucleus are substituted, the substituents may be the same or different. Examples of the hydrocarbon group having 1 to 4 carbon atoms include methyl group, ethyl group, probyl group,
Examples include butyl group, isoprobyl group, and isobutyl group.

Such monomers are phthalic acid esters containing two unsaturated groups, and there are 〇 monomers, m monomers, and p monomers.

When such a monomer is used as a copolymerization component, it generally undergoes gelation as the polymerization progresses and becomes insoluble in organic solvents, so various considerations must be taken during polymerization. From this point of view, the monomers described above are preferably monolithic, and n is an integer of 0 to 3. Preferred specific examples of such monomers include vinyl esters such as divinyl phthalate and divinyl isophthalate, allyl esters such as diallyl phthalate and diallyl isophthalate, diisobropenyl phthalate, and diisopropenyl isophthalate. Among them, diallyl phthalate is particularly preferred from the viewpoint of polymerization controllability and economical efficiency. These monomers may be used alone or in combination of two or more.

In the polymer of the present invention, the content of the (B) units is 5
It is necessary that the amount is in the range of 90 mol% to 90 mol%, preferably 30 to 70 mol%. If this content is less than 5 mol%,
Gloss and rigidity are poor, and if it exceeds 90 mol%, weather resistance is significantly reduced.

The polymer of the present invention has the above-mentioned specific amounts of (A) and (B) units as essential constituent units, thereby improving its solubility in solvents, being thermocurable, and particularly improving gloss and hardness. Although it can form an excellent coating film, in addition to these units, depending on the purpose of use, etc.
It may also contain other copolymerizable monomer units in an amount not exceeding 40 mol%.

Examples of the copolymerizable monomer include olefins such as ethylene, propylene, and isobutylene, vinyl chloride,
Haloolefins such as vinylidene chloride, vinyl acetate,
Carboxylic acid vinyl esters such as vinyl n-monobutyrate, carboxylic acid isobrobenyl esters such as isobropenyl acetate and isopropenyl propionate, ethyl vinyl ether, probyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, tert-butyl vinyl ether, benzyl vinyl ether , chain alkyl vinyl ethers such as hexyl vinyl ether, isohexyl vinyl ether, octyl vinyl ether, 4-methyl-1-pentyl vinyl ether, cycloalkyl vinyl ethers such as cyclopentyl vinyl ether, cyclohexyl vinyl ether, phenyl vinyl ether, o-, m-, p- Aryl vinyl ethers such as tolyl vinyl ether, aralkyl vinyl ethers such as benzyl vinyl ethers and phenethyl vinyl ether, aromatic vinyl compounds such as styrene and vinyltoluene, and hydrolyzable silyl groups such as vinyltrimethoxysilane and allyltriethoxysilane. Silane compounds with unsaturated bonds, di- or monoesters and acid anhydrides of unsaturated bond-containing polybasic acids such as fumaric acid and maleic acid, acrylics such as hydroxyethyl acrylate, hydroxyethyl methacrylate, methyl methacrylate, and glycidyl methacrylate. Acids and methacrylic acid esters, acrylamides such as acrylamide and N-methylolacrylamide, allyl ethers such as allyl glycidyl ether and ethyl allyl ether, carboxylic acid allyl esters such as allyl acetate and allyl blobionate, allyl alcohol, etc. Can be mentioned. Among these, carboxylic acid vinyl esters and vinyl ethers are particularly preferred because they have good reactivity with fluoroolefins.

One type of these copolymerizable monomers may be used, or two types of these copolymerizable monomers may be used.
You may use combinations of more than one species.

The molecular weight of the fluoropolymer of the present invention is determined by the number average determined by gel permeation chromatograph (GPC) method using tetrahydrofuran as a solvent and monodisperse polystyrene of known molecular weight as a standard substance. Molecular weight (
It is necessary that M n ) be in the range of 1000 to 200,000, preferably 2000 to 100,000. If the number average molecular weight (Mn) deviates from the above range, the object of the present invention cannot be fully achieved.

The fluoropolymer of the present invention is characterized by the presence of unsaturated groups in the polymer. The unsaturated group is derived from the (B) unit, and it is preferable in the present invention that the residual rate of the unsaturated group in the (B) unit in the fluoropolymer is in the range of 10 to 50%. .

If the unsaturated group residual rate is less than 10%, branched structures and three-dimensional crosslinked structures increase in the polymer, resulting in a decrease in the solubility of the polymer in solvents and a decrease in the number of cured sites during thermosetting. This results in a decrease in physical properties. On the other hand, in the case of a linear polymer without any crosslinking, it is 50%. Therefore, in a range exceeding 50%, it means that impurities having unsaturated groups other than the polymer, such as unreacted monomers, are present, causing a decrease in physical properties. The residual rate of unsaturated groups in the polymer can be determined by measuring the infrared absorption spectra of the polymer and monomer (B), and determining the peak of the carbon-carbon double bond (1650 cm-') and the peak of the benzene nucleus ( l
fi00cm-') can be calculated using the following equation.

Unsaturated group residual rate (%) = I(a/b)/(c/d
) l X 100a: 165 according to IR measurement of the polymer
Absorbance at 0cII+-' b = Absorbance at 1800 cm ' as determined by IR measurement of the polymer C: Absorbance d at 1650 cm-' as determined by IR measurement of the (B) unit monomer of the polymer: (B) of the polymer 1 by IR measurement of unit monomer
Absorbance at 800 cm-' The fluoropolymer of the present invention having such a composition and molecular weight is soluble in organic solvents, heat curable, and has excellent gloss and hardness.

The fluoropolymer of the present invention can be produced by copolymerizing a monomer mixture at a predetermined ratio in the presence or absence of a solvent using a polymerization initiator, ionizing radiation, etc. as a polymerization initiation source. I can do it.

As the polymerization initiator, water-soluble or oil-soluble ones are appropriately used depending on the type of polymerization and the type of solvent used as desired.

Water-soluble polymerization initiators include, for example, persulfates such as potassium persulfate, hydrogen peroxide, or redox initiators consisting of combinations of these with reducing agents such as sodium bisulfite and sodium thiosulfate. Inorganic initiators coexisting with small amounts of iron, ferrous salts, silver nitrate, etc., dibasic acid peroxides such as disuccinic acid peroxide, diglutaric acid peroxide, monosuccinic acid peroxide,
Examples include organic initiators such as azobisisobutyramidine dibasic acid salt. In addition, examples of the ura-soluble initiator include peroxy ester type peroxides such as t-butyl peroxyisobutyrate and t-butyl peroxy acetate, dialkyl peroxydicarbonates such as diisopropyl peroxydicarbonate, Examples include penzoyl peroxide and azobisisobutyronitrile.

The amount of these polymerization initiators to be used is appropriately selected depending on the type thereof, copolymerization reaction conditions, etc., but is 0.005 to 5% by weight, preferably 0.005 to 5% by weight, based on the total amount of monomers normally used.
It is selected in the range of 0.05 to 0.5%. There are no particular restrictions on the polymerization method; for example, bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization, etc. can be used; From the point of view of ease, emulsion polymerization in an aqueous medium, alcohols such as t-butanol, esters, fluorine atom 1
Preferably used are a solution polymerization method using a saturated halogenated hydrocarbon having 1 or more halogenated hydrocarbons as a solvent, a bulk polymerization method that does not require separation from a solvent, and the like.

When copolymerizing in an aqueous medium, a suspending agent or emulsifier is usually used as a dispersion stabilizer, and a basic buffer is added to adjust the pH value of the reaction solution during polymerization to 4, preferably 6 or higher. It is desirable to do so.

Further, addition of a basic substance is also effective in the case of solution polymerization method and bulk polymerization method. Furthermore, there are no particular limitations on the polymerization format, and any of the batch, semi-continuous, and continuous methods can be used.

The reaction temperature in the copolymerization reaction is usually -30 to +15
Within the range of 0°C, it is appropriately selected depending on the polymerization initiation source and the type of polymerization medium. For example, when copolymerization is carried out in an aqueous medium, the temperature is usually 0 to 100°C, preferably 10 to 90°C. To be elected. The reaction pressure is not particularly limited, but is usually selected within the range of 1 to 100 kg/ctl, preferably 2 to 50 kg/cd. Furthermore, the copolymerization reaction can be carried out by adding a suitable chain transfer agent.

The fluorine-containing polymer of the present invention contains an unsaturated group as a curing site, and is heat-cured using a curing agent used for the heat-curing of ordinary unsaturated polymers, such as an organic peroxide. be able to.

Various solvents can be used to prepare the fluoropolymer into a solution-type coating material. Examples of the solvent include aromatic hydrocarbons such as toluene and xylene, alcohols such as n-butanol, ketones such as methyl isobutyl ketone, glycol ethers such as ethyl cellosolve, and various commercially available thinners. It will be done. Solutions obtained by dissolving the fluorine-containing polymer in these solvents are either slightly yellow, colorless and transparent, or colorless and transparent.

The solution-type coating material is prepared by mixing the fluoropolymer and a solvent using a mixer commonly used for preparing paints, such as a ball mill, paint shaker, sand mill, jet mill, three-roll mill, kneader, etc. This can be done by homogeneously mixing. At this time, pigments, dispersion stabilizers, viscosity modifiers, leveling agents, antigelation agents, ultraviolet absorbers, etc. may be added as desired.

Furthermore, the fluoropolymer can also be used as a molding material. In this case, it can be handled in the same manner as the polymer commonly known as diallyl phthalate brevolimer. Furthermore, the fluoropolymer can be used as a crosslinking agent for various polymers by utilizing the unsaturated groups at the curing site.

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

Example 1 After degassing, 113 g of diallyl phthalate (hereinafter referred to as DAP) and methyl isobutyl ketone (hereinafter referred to as MIB) were placed in a stainless steel autoclave with an internal volume of 1 liter and equipped with a stirrer.
500 ml of chlorotrifluoroethylene (hereinafter abbreviated as CTFE) 268 g and 5 g of t-butyl peroxy pinolate (NOF ■ product [Verbutyl PVJ) were charged, and the internal temperature was raised to 60°C. Thereafter, the reaction was continued while stirring, and after 8 hours, the stirring was stopped and unreacted monomers were purged to terminate the reaction. The autoclave was opened and the reaction solution was taken out. After concentration, it was reprecipitated with methanol and washed to obtain a polymer. The yield of the obtained polymer was 72 g. When the composition of this polymer was analyzed using elemental analysis and IR analysis, CTF
E/DAP-39/61 (molar ratio). Also,
The number average molecular weight of this polymer was 7,300, and the residual rate of unsaturated groups was 43%. This polymer log is M I
BK was dissolved in 10.4 g, and 0.4 g of Perhexa 25BJ (manufactured by NOF ■) was added as a hardening agent and mixed. This solution was applied to a white tile plate and a glass plate using an ablator. After that, it was dried at room temperature for 30 minutes, and then heated for 10 minutes at 180° C. After heating, a robust and transparent coating film was obtained on the cooled board, which did not corrode even when wiped with MIBK with a thickness of about 100 μm. It was done.

The surface gloss of this coating film according to JIS K5400 is 98% at 60° specular reflection, and it is ISO-
The Konig hardness according to 1522 was 140.

Examples 2 and 3 Polymers were produced in the same manner as in Example 1 using the types and amounts of monomers shown in Table 1.

The yield, molecular weight, composition ratio, unsaturated group residual rate, and surface gloss formed in the same manner as in Example 1 of the obtained polymer, k'
6nlg hardness is shown in Table 1.

Table 1 Comparative Examples 1 to 4 Polymers were produced in the same manner as in Example 1 using the types and amounts of monomers shown in Table 2.

Table 2 shows the yield, molecular weight and composition ratio of the obtained polymer.

The obtained polymer log was dissolved in MIBKlOg, and "Duranate TPAj (manufactured by Asahi Kasei Corporation)" was added as a curing agent so that the hydroxyl groups and isocyanate groups of the polymer were equivalent, and degreased with acetone. It was applied to the treated white tile and glass plates using an applicator, dried at room temperature for 30 minutes, and then baked and cured at 120°C for 1 hour.The surface gloss and k6nlg hardness of the coating film thus obtained were Shown in the table.

Table 11I2 (Charcoal: II: Carboxylic acid vinyl ester having several 8 fll of alkyl groups (trade name: Veover 9, manufactured by Shell Chemical Co., Ltd.) [Effects of the invention] As explained above, the fluorine-containing polymer of the present invention and,
It has good solubility in organic solvents, is heat curable, and can form coatings with excellent gloss and hardness.

[Brief explanation of drawings]

The attached drawing is an IR absorption spectrum diagram of the polymer obtained in Example 1.

Claims (1)

[Scope of Claims] (A) 10 to 60 mol% of fluoroolefin units, (B
) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [R in the formula is hydrogen or methyl group, X is fluorine, chlorine,
bromine or a hydrocarbon group having 1 to 4 carbon atoms, n is an integer of 0 to 3, m is an integer of 0 to 4) units 5 to 9
A fluoropolymer containing 0 mol% as an essential structural unit and having a number average molecular weight (@M@n) of 1000 to 200,000 as measured by gel permeation chromatography.