JPS62169810A - Production of fluorine-containing copolymer - Google Patents

Abstract

PURPOSE:To obtain the titled copolymer which can give a film excellent in hardness and weathering resistance, by copolymerizing a specified amount of a fluoroolefin with a specified amount of a vinyl ester of an aliphatic carboxylic acid and a specified amount of a hydroxylalkyl vinyl ether in an organic medium. CONSTITUTION:100mol of a monomer mixture of 20-50mol of a fluoroolefin (a) (e.g., chlorotrifluoroethylene), 1-20mol of 6-18C aliphtatic carboxylic acid vinyl ester (b) (e.g., vinyl versatate) and 1-20mol of a 2-6C hydroxyalkyl group-containing hydroxyalkyl vinyl ether is copolymerized at 0-150 deg.C and a pressure of 0-50kg/cm<2> G in an organic medium (B) in an amount to provide 100mol of the total of this medium and at least 45mol of component A in the presence of 0.01-5pts.wt., per 100pts.wt. component B, organic or inorganic weak basic substance and 0.1-3pts.wt. per 100pts.wt. component A, radical initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a fluorine-containing copolymer used in a room-temperature curing fluororesin coating.

[Conventional technology]

In recent years, fluorine-containing copolymers that can be cured at room temperature have begun to be used as fluororesin paints. Fluorine-containing copolymers that are actually often used in cold-curing fluororesin paints are alternating copolymers of fluoroolefins and various vinyl ether compounds (Japanese Patent Application Laid-open Nos. 49-13229, 57-34107, and Kaisho 59-189108
(see Japanese Patent Publication No. 2003-110013), and is produced by solution polymerization in an organic medium.

When aliphatic carboxylic acid vinyl esters, which are cheaper than vinyl ethers, are copolymerized with fluoroolefins in place of some vinyl ethers, the polymerizability of the fluoroolefins is improved (
Therefore, the amount of fluoroolefin contained in the copolymer is smaller than when only vinyl ether is copolymerized.

(contains), a small amount of fluoroolefins contained in a copolymer means that there is a large loss of fluoroolefins; The hardness and weather resistance of the coating film, which is mainly composed of

[Purpose of the invention]

The present inventors conducted extensive studies on the production method of fluoroolefins/aliphatic carboxylic acid vinyl esters/vinyl ether copolymers, and found that monomers such as fluoroolefins, aliphatic carboxylic acid vinyl esters, and vinyl ethers present in the polymerization system The present invention was achieved based on the new finding that the amount of fluoroolefins contained in the copolymer changes depending on the total concentration of the polymers.

An object of the present invention is to provide a method for obtaining a fluorine-containing copolymer having a high fluoroolefin content.

[Structure of the invention]

The gist of the present invention is to copolymerize fluoroolefins, aliphatic carboxylic acid vinyl esters, and hydroxyalkyl vinyl ethers in an organic medium. A method for producing a fluorine-containing copolymer, characterized in that 45 moles or more are used per 100 moles of ester, hydroxyalkyl vinyl ether, and organic medium in total.

The amount of fluoroolefins, aliphatic carboxylic acid vinyl esters and hydroxyalkyl vinyl ethers used is
If the molar ratio of the fluoroolefin, aliphatic carboxylic acid vinyl ester, hydroxyalkyl vinyl ether, and hydroxyalkyl vinyl ether is less than 45 mol per 100 mol of the total of the fluoroolefin, aliphatic carboxylic acid vinyl ester, and hydroxyalkyl vinyl ether, the molar ratio of the fluoroolefin, aliphatic carboxylic acid vinyl ester, and hydroxyalkyl vinyl ether is 45 mol or more. Even if the case is the same as in the above case, the amount of fluoroolefin contained in the produced copolymer is smaller than in the case of 45 moles or more. If the amount of fluoroolefins contained in the copolymer is small, sufficient physical and chemical properties cannot be obtained as a coating material.The preferred amount of fluoroolefins contained in the copolymer is 50 to 80 mol%. .

As the fluoroolefins, known fluorine-containing monomers such as chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropene, fluoroalkyl vinyl ether, vinyl fluoride, vinylidene fluoride, and trifluoroethylene can be used. The amount of fluoroolefin used is usually 20 to 50 mol per 100 mol of total monomers.
mol, preferably 25 to 40 mol.

The aliphatic carboxylic acid vinyl ester usually has 6 carbon atoms.
-18, such as vinyl versatate, vinyl laurate, vinyl stearate, etc. The amount of aliphatic carboxylic acid vinyl ester used is usually 100% of the total monomer.
The amount is 1 to 20 mol, preferably 3 to 18 mol.

The hydroxyalkyl group of the hydroxyalkyl vinyl ether usually has 2 to 6 carbon atoms.

The hydroxyl group is usually attached at the ω position, but may be at other positions. The amount of hydroxyalkyl vinyl ether used is usually 1 to 2 per 100 moles of total monomers.
0 mol, preferably 3 to 18 mol.

As the organic body, those generally used in preparing fluoropolymers can be used. Examples of organic media include esters, aromatics, ketones, glymes, alcohols, amides, and sulfoxides. The organic medium may be a mixture.

When carrying out the present invention, the fluoride anion may be desorbed from the produced copolymer, and this may act as a catalyst to cyclize the hydroxyalkyl vinyl ether. An organic or inorganic weakly basic substance, such as a tertiary amine, carbonate, etc., is added to the solution. The amount of the weakly basic substance used is usually 0.01 to 5 parts by weight, preferably 0.1-1 parts by weight per 100 parts of the organic medium.
Parts by weight.

The polymerization of the present invention is carried out using a radical initiator. Examples of radical initiators include azo compounds such as abisisobutyronitrile and azobisvaleronitrile, and peroxides such as isobutyryl peroxide, octanoyl peroxide, and di-isopropyl peroxide. The radical initiator is usually used in an amount of 0.1 to 0.1 to the total monomer.
Use 3 parts by weight.

The polymerization temperature for the polymerization of the present invention is 0 to 150°C, preferably 5 to 95°C, and the polymerization pressure is 0 to 50 kg/cm''G, preferably 0 to 15 kg/cm2G.

The fluorine-containing copolymer obtained by the production method of the present invention can be used as a lacquer-type paint as it is, but it can be used by adding a curing agent having two or more groups that can react with the hydroxyl groups contained in the copolymer. can do. Examples of curing agents include hexamethylene di-isocyanate trimer, tolylene di-isocyanate, and isophorone-di-isocyanate.
Isocyanates such as di-isocyanate and block isocyanate, melamines such as methylol melamine and butyrol melamine, urea resin, hexamethylene di-
There are acid halides such as carbonyl chloride. The curing agent is usually used in an amount of 0.5 to 2 equivalents per equivalent of hydroxyl group.

When the fluorine-containing copolymer obtained by the production method of the present invention is used as a coating material, in addition to the above-mentioned curing agent, a curing accelerator, a pigment, a viscosity modifier, a leveling agent, an anti-gelling agent, an anti-scalding agent, and ultraviolet rays. Absorbents, solvents, etc. can be added.

〔Example〕

Example 1 Looom equipped with a stirrer! ! 197.2 g of butyl acetate, 84.5 g of ethyl acetate, 28.1 g of toluene, and 5 m of dimethylbenzylamine Q in an autoclave.
174.2 g of vinyl versatate (Shell Petrochemical Type Veover 10, hereinafter referred to as VA) and hydroxybutyl vinyl ether (hereinafter referred to as I (B V E
That's what it means. ), and after sealing, purging with nitrogen gas, 220 g of chlorotrifluoroethylene (hereinafter referred to as CTFE) was charged.

After heating the autoclave to 65° C., 2.5 g of abbisisobutyronitrile was added to initiate polymerization.

The temperature was maintained for 18 hours with stirring. The autoclave pressure was initially 5.9 kg/cm"G, but gradually decreased to 4.3 kg/cm"G.

After cooling, the remaining monomer was released. Solid concentration is 52
．． 650 g of a 7% by weight fluorine-containing copolymer solution was obtained.

A portion of the obtained solution was poured into isopropanol to solidify the fluorine-containing copolymer. It was then washed with isopropanol and after drying, elemental analysis and 'H-N
MR analysis was performed. As a result, the fluorine-containing copolymer,
C T F E 52. ．． 8 mol % of VA, 32.2 mol % of VA, 14.9 mol 9 of HB VE, and it was found that CTFE was contained in 67.2% of the charged amount.

Elemental separation: 48.9% carbon, 13.2% chlorine and 20.9% fluorine.

'H2N M RJJ'i-: δ (ppm); 0.
7 to 2.0 (side chain methyl group and methine group),
3.4-4.1 ((Methylene group of the same rule).

Example 2 A fluorine-containing copolymer solution was prepared in the same manner as in Example 1 except that CTFEI in Example 1 was changed to 146.8 g. 615 g of a fluorine-containing copolymer solution having a solid content concentration of 50.3% by weight was obtained.

A portion of the obtained solution was taken and a fluorine-containing copolymer was obtained in the same manner as in Example 1, and elemental analysis and '
H-NMR analysis was performed. As a result, the fluorine-containing copolymer was found to be composed of 45.4 mol% CTFE, 41.1 mol% VA, and 13.5 mol% HBVE;
It was found that FE contained 74.3% of the charged amount.

And lack of claim: carbon 53.3%, chlorine 10.8% and fluorine 17.1%.

``Land-side pressure milk raw Kaji: δ (91m); 0.7 to 2.0 (methyl group and methine group in side chain), 3.4 to 4.1 (methylene group in side chain).

Comparative Example In the same autoclave as in Example 1, the same amounts of butyl acetate, ethyl acetate, toluene and dimethylhensylamine as in Example 1 and v A , 125 g and 118 VB
Charge 29.3 g, seal, purge with nitrogen gas, and
55 g of TFEI was charged.

After heating the autoclave to 65° C., 2.5 g of azobisisobutyronitrile was added to initiate polymerization.

Pj while stirring? It was kept at ms degree for 18 hours.

After cooling, the remaining monomer was released. Solid concentration is 42
．． 543 g of a 9% by weight fluorine-containing copolymer solution was obtained.

A portion of the obtained solution was taken and a fluorine-containing copolymer was obtained in the same manner as in Example 1, and elemental analysis and '
H-NMR analysis was performed. As a result, the fluorine-containing copolymer consisted of 45.2 mol% CTFE, 40.3 mol% VA, and 14.5 mol% HB VE, and CTFE was contained in 53.0% of the charged amount. I understand.

Original chestnut ash: 53.3% carbon, 10.9% chlorine and 17.1% fluorine.

” 1 tithe value: δ (ppm); 0.7 to 2.0 (
side chain methyl group and methine group), 3.4 to 4.1 (
side chain methylene group).

Reference Example and Comparative Reference Example Butyl acetate was added to the fluorine-containing copolymer solution prepared in Example 1 and Comparative Example, and diluted to 45 parts. 35 g of rutile titanium oxide and 8 g of xylene were added to 100 g of the diluted solution and mixed for 1 hour using a paint shaker.

dibutyltin laurate 2 rrt in each mixture
g of hexamethylene-diisocyanate trimer (Coronate EH manufactured by Nippon Polyurethane Co., Ltd.) was added to the mixture prepared from the fluorine-containing copolymer solution of Example 1.
．． 6 g of the same hexamethylene di-isocyanate trimer as above was added to a mixture prepared from the fluorine-containing copolymer solution of the comparative example. Additional xylene was added to each mixture to bring the viscosity of the mixture to approximately 300 centivoids.

Each of the prepared mixtures was applied to an aluminum plate (BT-712 treatment manufactured by Nippon Test Panel Co., Ltd.) with a brush,
It was left to stand at 25°C for 24 hours and at 80°C for 8 hours to cure. The average thickness of the coating film after curing was 30 μm. A pencil hardness test (
JIS K 5400) and weather resistance tests were conducted. In addition,
For the weather resistance test, a Ducycle tester (manufactured by Suga Test Instruments Co., Ltd., light source: Sunshine Carbon, panel temperature: 63°C, cycle: 60 minutes/60 minutes [lights on/off])
) and 60°-60m before and after 360 hours exposure treatment.
The specular glossiness (JIS Z8741) was measured and the gloss retention rate was investigated. The results are shown in the table.

Table [Effects of the Invention] According to the production method of the present invention, fluoroolefins,
By using aliphatic carboxylic acid vinyl ester and hydroxyalkyl vinyl ether in a certain amount or more with respect to the total amount of fluoroolefins, aliphatic carboxylic acid vinyl esters, hydroxyalkyl vinyl ethers, and the existing medium, a fluorine-containing copolymer containing a large amount of fluoroolefins can be produced. Coalescence can be obtained, and there is little loss of fluoroolefins.

When the charging ratio of fluoroolefins is increased, the amount of fluoroolefins contained in the fluorine-containing copolymer increases, but this method results in a large loss of fluoroolefins.

that's all

Claims (1)

[Claims] 1. When copolymerizing fluoroolefins, aliphatic carboxylic acid vinyl esters, and hydroxyalkyl vinyl ethers in an organic medium, fluoroolefins, aliphatic carboxylic acid vinyl esters, and hydroxyalkyl vinyl ethers are copolymerized with fluoroolefins, aliphatic carboxylic acid vinyl esters, and hydroxyalkyl vinyl ethers. A method for producing a fluorine-containing copolymer, characterized in that 45 moles or more are used per 100 moles of vinyl ether and organic medium in total.