JPH03212459A - Fluorine-containing resin composition for coating compound - Google Patents

Abstract

PURPOSE:To obtain the title composition having improved pigment dispersibility, soluble in organic solvents, comprising fluoroolefin, carboxylic acid vinyl ester, hydroxyl group-containing allyl ether and a specific carboxyl group-containing monomer in a specific ratio. CONSTITUTION:The objective composition comprising (A) 25-75mol%, preferably 40-60mol% fluoroolefin (preferably chlorotrifluoroethylene or tetrafluoroethylene), (B) 5-70mol%, preferably 20-50mol% carboxylic acid vinyl ester (e.g. vinyl acetate), (C) 3-40mol%, preferably 5-30mol% hydroxyl group-containing allyl ether [preferably monomer shown by formula I or formula II ((m) is 1-5; (n) is 1-10)] and (D) 0.1-20mol%, preferably 0.3-10mol% carboxyl group-containing monomer shown by formula III (l) is 1-10) prepared by modifying vinyl acetate with caprolactone as essential components.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a fluorine-containing resin composition for paints, and more specifically to a fluorine-containing resin composition that is soluble in organic solvents and has significantly improved pigment dispersibility. Regarding resin.

(Conventional technology) Conventional paints using fluorine-containing polymers have excellent weather resistance, heat resistance, chemical resistance, etc., and are used in the chemical industry, architecture, food,
It is widely used in fields such as machinery.

Particularly in recent years, solvent-soluble fluororesin paints with improved workability have been in the spotlight.

These paints have increased solubility in organic solvents, allowing them to be dissolved in common paint solvents, and can be cured at room temperature instead of the conventional paints that had to be baked at high temperatures. Like hydrocarbon-based solvent-based paints, it can be applied on-site, and its weather and chemical resistance make it a long-term, maintenance-free paint that is increasingly used in architecture, civil engineering, and machinery and metals.

(Problems to be Solved by the Invention) In order to make a fluororesin soluble in an organic solvent, it is usually necessary to disrupt the crystallinity of the fluororesin by a method such as copolymerization and to internally plasticize it.

Furthermore, in order to use this as a paint, there are issues such as how to maintain the inherent rigidity of the resin, the molecular weight of the resin to adjust the viscosity of the paint, and the need to maintain chemical resistance and repaint. In order to make this possible, it is necessary to introduce a functional group into the resin and cure it, and in this case there are problems such as how to select the type and amount of the functional group and cost issues.

Furthermore, when applying organic solvent-soluble fluorine resins to paints, the dispersibility of pigments becomes an important issue. In other words, if the dispersibility of the pigment is poor, color unevenness will occur during application, color separation will occur during storage, and the performance as a paint will deteriorate. In this way, in the case of fluororesin paints, the fluorine atoms they contain are inert, so they have poor wettability to pigments and are considered difficult to disperse.

Therefore, efforts are being made to improve pigment dispersibility by introducing polar groups such as carboxyl groups into polymer compounds.
It has also been partially implemented industrially. In addition, attempts have been made to introduce carboxyl groups into fluorine-containing polymers. For example, in JP-A-58-136605, after synthesizing a fluorine-containing polymer containing hydroxyl groups, some of the hydroxyl groups are modified and carboxyl groups are introduced. A method has been proposed.

However, in this case, there are problems in that it is a two-step reaction in which the copolymer is synthesized and then modified, and that the reaction temperature is high because it is a reaction for polymers, which tends to cause coloration.

Therefore, the present inventors proposed a method for introducing a carboxyl group into a copolymer in one step by making the carboxyl group-containing monomer exist as a comonomer during polymerization (Japanese patent application No. 6
3-118353).

Examples of the carboxyl group-containing monomer in this case include acrylic acid, vinyl acetic acid, alkyloxyacetic acid, and the like, as those that hardly inhibit the copolymerization reaction.

The present inventors synthesized a fluorine-containing copolymer resin using the above-mentioned carboxyl group-containing monomer, and as a result of intensively examining its dispersibility with respect to various pigments, by introducing a carboxyl group into the polymer chain, Although the pigment dispersibility was significantly improved, it was found that it was still insufficient for certain pigments.

As a result of further investigation into the types of carboxyl group-containing monomers, we found that by using a long-chain monomer made by modifying vinyl acetic acid with ε-caprolactone, it increased its affinity with pigments and further improved pigment dispersibility. They discovered that the invention could be further improved and completed the present invention.

(Means for Solving the Problems) That is, the present invention has as essential components a monomer obtained by modifying a fluoroolefin, a carboxylic acid vinyl ester, a hydroxyl group-containing allyl ether, and a vinyl acetic acid with ε-caprolactone. By polymerizing a monomer mixture to which alkyl vinyl ether has been added in the presence of a radical initiator, the coating material has excellent physical properties such as weather resistance and chemical resistance, is economically advantageous, and has excellent pigment dispersibility. It has been discovered that a fluorine-containing resin can be produced.

Examples of the fluoroolefins used in the present invention include trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinyl fluoride, and hynylidene fluoride. Ethylene and tetrafluoroethylene are preferred.

Examples of carboxylic acid vinyl ester include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl incaproate, vinyl bivalate, vinyl caprylate, vinyl capricate, vinyl stearate, Beopa 9 (Showa Shell Oil), Beoba 1
Examples include fatty acid vinyl esters such as 0 (manufactured by Showa Shell Sekiyu) and aromatic carboxylic acid vinyl esters such as vinyl benzoate and vinyl pt-butylbenzoate. It is also possible to use two or more of these vinyl esters in combination.

As the hydroxy group-containing allyl ether, the general formula CH
2=CHCH2-0(CH'2CH2-0)l, lH(
Ethylene glycol monoallyl ether (m is an integer of 1 to 5) or ethylene glycol monoallyl ether modified with ε-caprolactone, monomer represented by the general formula (%) (n is an integer of 1 to 10) The use of modified products improves the yield and the strength and elongation of the coating film.

In addition, as a carboxyl group-containing monomer obtained by modifying vinyl acetic acid with ε-caprolactone, one represented by the general formula % (manufactured by Daicel Chemical) (manufactured by Daicel Chemical) is preferable from the viewpoint of pigment dispersibility. It is something.

In addition, as the alkyl vinyl ether added as necessary, methyl vinyl ether, ethyl vinyl ether, n
-butyl vinyl ether, isobutyl vinyl ether,
Examples include 2-ethylhexyl vinyl ether and isooctyl vinyl ether, but ethyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether are preferred in consideration of economical efficiency and ease of handling.

Next, as a typical composition of the copolymer resin in the present invention, the content of fluoroolefin, carboxylic acid vinyl ester, hydroxyl group-containing allyl ether, ε-caprolactone-modified monomer of vinyl acetic acid, and alkyl vinyl ether is 25 to 75%. mol%, 5-70 mol%, 3-4
0 mol%, 0.1-20 mol% and 0-50 mol%, preferably 40-60 mol% and 20-5 mol%, respectively.
The ranges are 0 mol%, 5-30 mol/L/%, 0.3-10 mol% and 0-40 mol%.

The content of fluoroolefin can be changed arbitrarily depending on the amount of each monomer when charging, but if it is too high, the solubility of the fluoro-containing paint resin in organic solvents will decrease, and the amount of fluoro-olefin will be reduced during production. There is a problem with the yield of resin for base paint, and conversely, if it is small, it is unfavorable from the viewpoint of physical properties such as weather resistance and chemical resistance.

In addition, a resin for fluorine-containing paints with too high a carboxylic acid vinyl ester content is undesirable from physical properties such as weather resistance and chemical resistance, and too low a content is undesirable from a manufacturing standpoint, such as a decrease in molecular weight and a decrease in yield. do not have. If the content of the caprolactone-modified product of hydroxyl group-containing allyl ether or ethylene glycol monoallyl ether is too high, the molecular weight will decrease and problems will also arise in terms of production. On the other hand, if the content is too low, the curing reaction with the curing agent becomes difficult to occur, resulting in a decrease in physical properties such as chemical resistance and weather resistance, and it becomes difficult to recoat.

In addition, if the proportion of the carboxyl group-containing monomer modified with caprolactone, which is a feature of the present invention, is too high, the water resistance and solubility of the resin for fluorine-containing paints, as well as the reaction yield, will deteriorate; if it is too low, the pigment dispersibility will deteriorate. Deteriorate. Furthermore, if the proportion of alkyl vinyl ether is too high, it will be disadvantageous from an economic point of view.

The resin for fluorine-containing paints of the present invention may be cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbon solvents such as benzene and toluene, ester solvents such as ethyl acetate and butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, It can be dissolved in ketone solvents such as cyclohexanone, amide solvents such as dimethylformamide and dimethylacetamide, and halogen-containing solutions M such as 1.1.1-trichloroethane and trichlorethylene.

The caprolactone-modified monomer of the fluoroolefin, carboxylic acid vinyl ester, hydroxyl group-containing allyl ether or ethylene glycol monoallyl ether of the present invention, or the monomer obtained by adding a modified carboxyl group-containing monomer and alkyl vinyl ether to the above three components The resin for fluorine-containing paints obtained by copolymerizing a mixture of fluorine and fluorine can be produced by any method such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk polymerization in the presence of a conventional radical initiator.

The polymerization temperature in producing resin for fluorine-containing paints varies depending on the type of polymerization initiator, but is between -30 and 130°C, preferably between 0 and 100°C.

The radical initiator is an oil-soluble radical initiator such as diisopropyl peroxydicarbonate, di-normal propyl peroxydicarbonate, tertiary butyl peroxybivalate, di-2-ethylhexyl peroxydicarbonate, benzoyl peroxide, lauroyl peroxide. , propionyl peroxide, trichloroacetyl peroxide, perfluorobutyryl peroxide, perfluorooctanoyl peroxide, and other peroxides, azobisisobutyronitrile, azobis-2
, 4-dimethylvaleronitrile, and organic boron compounds such as triethylboron-oxygen or peroxide.

The purity of the comonomer may be less than 98% by gas chromatography as long as it does not contain impurities that do not interfere with normal radical polymerization.

The fluorine-containing paint resin thus obtained has active hydrogen in its molecule, and therefore can be cured with a compound having a functional group that reacts with active hydrogen. That is, by adding polyvalent isocyanates to a solution in which a fluorine-containing paint resin is dissolved in the above-mentioned solvent and scattering the solvent, the reaction proceeds at room temperature. By treating at a temperature higher than the temperature at which the valent incyanate dissociates, the curing reaction progresses, and a cured coating film is obtained. It can also react with melamine, urea resin, polybasic acids or their anhydrides at high temperatures to form a cured coating film.Furthermore, the solution of this fluorine-containing paint resin contains pigments, ultraviolet absorbers, and dispersion stabilizers. It is also possible to add agents, etc., and good dispersibility is exhibited in either case.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 123.9 g of vinyl acetate (VAc) was placed in a stainless steel autoclave with a content of 1.41 g and equipped with a magnetic stirrer.

Ethylene glycol monoallyl ether (EGM A
E) 37.9 g, ε-caprolactone modified monomer of vinyl acetic acid (VAA) (n=1) 8.0 g, Perloyl NPP (NOF brand name) 2.5 g, butyl acetate (Bu Ac) ) and 0.6 g of calcium carbonate were charged, and the inside of the autoclave was degassed by replacing with nitrogen gas three times. Then chlorotrifluoroethylene (C
After introducing 263.8 g of TFE) into the autoclave, the temperature was gradually raised. After polymerization at 40°C for 24 hours,
Unreacted CTFE was removed and the autoclave was opened.

The polymerization solution was then taken out, washed with water to remove impurities, and dried to obtain 338 g (yield: 78%) of a copolymer resin. The molecular weight (Mn) of the obtained resin was 17.100 (number average molecular weight in terms of polystyrene), and the OH value was 52 KOH/
g (acetylation method using acetic anhydride), acid value 6■KOH
/g (JISK5400).

Examples 2 to 5 and Comparative Examples 1 to 2 Polymerization was carried out in the same manner as in Example 1 using the copolymerization charge composition shown in Table 1 (however, the amount of Baroyl NPP charged was 0.5 wt%/monomer). , yield, molecular weight, OH value, acid value, etc. were measured. The results are shown in Table 1.

The fluorine-containing resins for paints obtained in Examples 1 to 5 and Comparative Examples 1 to 2 were dissolved in a mixed solvent of butyl acetate and toluene, and the resin solid content concentration was adjusted to 50-t%.

Next, inorganic and organic pigments shown in Table 2 were added to these resin liquids (faces) and dispersed in a ball mill to prepare colored paints. The amount of each pigment was 25 parts by weight for the inorganic pigment, 6 parts by weight for the organic pigment, and 3 parts by weight for the carbon blank, based on 100 parts by weight of the face.

Next, the pigment dispersibility of the colored paint was determined by (1) the pigment sedimentation rate of the solution in which the pigment was dispersed, (2) a rubbing test using a mixed color paint, and (3) the color difference between spray and flow coating. A total of 15 points were evaluated for each item in 5 stages, and the results are shown in Table 2, with scores of 10 or higher being ○, 10 or lower, and 5 or lower being ×.

Table 2 (Effects of the Invention) The copolymer of the present invention has excellent adhesion and weather resistance as a paint, and is highly dispersible with pigments, especially organic pigments.

Procedural amendment

Claims (1)

[Scope of Claims] 1) 25 to 75 mol% of fluoroolefins, 5 to 70 mol% of carboxylic acid vinyl esters, 3 to 40 mol% of hydroxyl group-containing allyl ethers, and vinyl acetic acid modified with caprolactone, general formula ▲ mathematical formula, Chemical formulas, tables, etc. are available ▼ A fluorine-containing resin composition for paints containing 0.1 to 20 mol% of a carboxy group-containing monomer represented by (l is an integer of 1 to 10) as an essential component. 2) The fluororesin composition for paint according to claim 1, wherein the fluoroolefin is chlorotrifluoroethylene or tetrafluoroethylene. 3) The hydroxyl group-containing allyl ether has the general formula CH
_2=CHCH_2-O(CH_2CH_2O)_mH
(m is an integer from 1 to 5) or a caprolactone-modified monomer represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (n is an integer from 1 to 10) The fluorine-containing resin composition for paint according to claim 1.