JPH0411617A - Fluorinated copolymer and its production - Google Patents

Abstract

PURPOSE:To obtain a fluorinated copolymer improved in weathering resistance, chemical resistance and adhesion to metal by copolymerizing fluoroethylene with a specified fatty acid vinyl ester or isopropenyl ester, allyl glycidyl ether and a hydroxyalkyl allyl ether. CONSTITUTION:25-75mol% fluoroolefin is copolymerized with 10-70mol% fatty acid vinyl ester or isopropenyl ester of formula I (wherein R1 is H or CH3; R2 is CnH2n+1; and n is 1-12), 10-70mol% allyl glycidyl ether of formula II, 3-70mol% hydroxyalkyl allyl ether of formula III (wherein R3 is CnH2n+1; and n is 0-5) and 0-20mol% another copolymerizable comonomer (e.g. ethyl acrylate) at -30 to 100 deg.C in the presence of an oil-soluble radical initiator in a solvent containing 0.05-5wt.% basic buffering agent (e.g. Na2CO3) and having a pH of 4-11 to obtain a fluorinated copolymer of an intrinsic viscosity (in tetrahydrofuran at 30 deg.C) of 0.03-2.0dl/g.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a curable fluorine-containing copolymer, and more specifically, fluoroolefin, fatty acid vinyl ester or fatty acid impropenyl ester, allyl glycidyl ether, and hydroxy copolymer. The present invention relates to a curable fluorine-containing copolymer containing an alkyl allyl ether as an essential component and a method for producing the same.

(Prior Art) Fluorine-containing polymers have traditionally been used as resins with excellent heat resistance, mechanical properties, chemical resistance, weather resistance, and the like. Attempts to use fluorine-containing polymers as paints have been made in the past, starting with tetrafluoroethylene polymers and chlorotrifluoroethylene polymers, and more recently, vinylidene fluoride copolymers and other synthetic fluoropolymers have been attempted. Modified fluororesin paints made by adding additives to resin paints are commercially available, and are mainly used in the chemical industry, food, architecture, machinery fields, etc. as coating materials that take advantage of their lubricity, non-stick properties, weather resistance, and chemical resistance.

However, since most of these paints are in the form of powder dispersed in water or special organic solvents, or in the form of powder itself, it is possible to form a uniform film only by heating it above the melting point of the resin. . Therefore, construction can only be carried out by highly specialized engineers and manufacturers, and it is a technique that requires a high degree of skill.

On the other hand, solvent-soluble fluororesin paints have been attracting attention in recent years. These increase solubility in organic solvents,
It is a hardening type paint that can be dissolved in ordinary paint solvents, and is gaining popularity as a long-term maintenance-free paint that takes advantage of its weather resistance and chemical resistance for construction, civil engineering, and machinery and metal applications.

(Problems to be Solved by the Invention) In order to make a fluororesin usable as an organic solvent, the crystallinity of the fluororesin is usually disturbed by a manufacturing method such as a copolymer.
Needs to be internally plasticized.

Furthermore, in order to use this as a paint, there are problems 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 recoat. 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 the problem of price.

Various methods have been proposed in attempts to solve the above-mentioned problems and apply fluororesins to solvent-based paints, including JP-A-5734107 and JP-A-57-34108.

(Means for Solving the Problems) The present inventors have discovered that a copolymer of chlorotrifluoroethylene and fatty acid vinyl ester exhibits high transparency over a wide wavelength range, high tensile strength, and excellent impact resistance. British Patent No. 888.104 or -
H, TOMAS et al. (J, Polymer 5cien
CE, 11(5), 455 (1953)), it has long attracted attention as a raw material for fluorine-containing paints. However, although a copolymer of chlorotrifluoroethylene and fatty acid vinyl ester alone produces a transparent, glossy, and hard coating film, it has the disadvantage that it cannot be overcoated. Therefore, we conducted extensive research on copolymerization with a monomer that has a functional group that can cause a curing reaction within a range that does not impair the physical properties mentioned above. Proposed a method to obtain a possible copolymer (Japanese Unexamined Patent Publication No. 61-5
7609) However, after that, the adhesion with the substrate,
In particular, as a result of intensive studies on improving adhesion to glass, it was revealed that copolymers containing epoxy groups as functional groups can further improve adhesion to glass and provide good cured coatings (particularly 1986-250016).

The present invention uses allylglycidyl ether, which is said to be difficult to undergo radical copolymerization, to fluoroolefin, fatty acid vinyl ester or fatty acid impropenyl ester, and hydroxyalkyl allyl ether.
It has been discovered that a functional group can be introduced by copolymerizing with a polyester, leading to the present invention.

The copolymer of the present invention comprises a fluoroolefin and (R,=H
or CHl, R+=CnHzn++ n=1~
an integer of 12) or aliphatic isopropenyl ester and 2CH2=CH-C
H2-0-CH, ~C) Allylglycidyl ether represented by l-CH2 and the formula CHz=CH-CHz-0-R:+
It is a fluorine-containing copolymer made by containing hydroxyalkyl allyl ether represented by -OH as an essential component and blending it with other comonomers, such as fluoroolefin, fatty acid vinyl ester or fatty acid isopropenyl ester,
The content of units based on allyl glycidyl ether, hydroxyalkyl allyl ether and other polymerizable comonomers is 25 to 75 mol%, 10 to 70 mol%, and 3 to 70 mol%, respectively, in the resulting copolymer composition; A curable fluorine-containing copolymer containing 3 to 40 mol% and 0 to 20 mol%, and having an intrinsic viscosity of 0.03 to 2.0 dl/g as measured at 30°C in tetrahydrofuran. It is a combination. Preferably, the content of units based on fluoroolefins, fatty acid vinyl esters or fatty acid isoflobenyl esters, allyl glycidyl ethers, hydroxyalkyl allyl ethers and other polymerizable comonomers is 40 to 60 mol%, 20 to 50 mol. %
, 5 to 30 mol %, 5 to 30 mol %, and 0 to 15 mol %.

The fluoroolefin content can be changed arbitrarily depending on the amount of monomer used in the preparation, but if the copolymer is too high, the solubility in organic solvents will decrease, and there will be problems with the copolymer yield during production. come out.

On the other hand, if the amount is small, it is unfavorable from the viewpoint of physical properties such as weather resistance and chemical resistance. In addition, a copolymer with too high a content of fatty acid vinyl ester or fatty acid isopropenyl ester is unfavorable from the viewpoint of physical properties such as weather resistance and chemical resistance, and a copolymer with too low content of fatty acid vinyl ester or fatty acid isopropenyl ester is unfavorable from the viewpoint of production as well, as it leads to a decrease in molecular weight. Too high a content of allyl glycidyl ether and hydroxyalkyl allyl ether leads to a decrease in molecular weight and also causes problems in terms of production. On the other hand, if the content is too low, the curing reaction becomes difficult to occur, resulting in a decrease in physical properties such as chemical resistance and weather resistance, making it difficult to recoat.

A feature of the compounds of the present invention is that they contain epoxy groups and hydroxyl groups based on hydroxyalkyl allyl ethers. By containing the hydroxyl group, the effect of accelerating curing is significantly improved and the adhesion to the base is improved.

Further, by adjusting the content of hydroxyl groups at this time, it is possible to control the curing speed.

The compound in the present invention can be mixed with another resin having a hydroxyl group, an amino group, or an isocyanate group, and then cured by heating. Here, examples of resins containing hydroxyl groups, amino groups, and isocyanate groups include melamine resins and polyisocyanates, but normally fluorine-containing copolymers are not necessarily made of these melamine resins, polyisocyanates, etc. (hereinafter referred to as curing agents). It is also known that they are not compatible with each other. In the compound of the present invention, the polarity of the compound of the present invention can be adjusted by adjusting the amount of hydroxyl groups, that is, the content of hydroxyalkyl allyl ether, and the compatibility can be improved. In other words, it is possible to produce a compound that has good compatibility with a more polar curing agent by increasing the hydroxyl group content, and with a less polar curing agent by decreasing the hydroxyl group content. .

In order to eliminate the drawbacks of methyl methacrylate copolymers, which are commonly used as coating resins, attempts have been made to mix the methyl methacrylate copolymers with fluororesins. These resins have poor compatibility and cannot be mixed sufficiently. Therefore, various methods have been studied to improve the compatibility, for example,
-605, it has been proposed to improve the compatibility by copolymerizing it with a special fluorine-containing monomer. The copolymer of the present invention can improve its compatibility with a methyl methacrylate copolymer and the like by adjusting the amount of hydroxyl groups, that is, the content of hydroxyalkyl allyl ether. In addition, as a methyl methacrylate copolymer with a high content of hydroxyl groups, the copolymer of the present invention with a large amount of hydroxyl groups is produced to improve compatibility, and as a methyl methacrylate copolymer with a low content of hydroxyl groups, The copolymer of the present invention having a small amount of hydroxyl groups can be produced to adjust the compatibility.

Furthermore, the solubility of the copolymer of the present invention in various organic solvents necessary for making it into a paint can be controlled by adjusting the amount of hydroxyl groups, that is, the content of hydroxyalkyl allyl ether.

The copolymer of the present invention is prepared at 30°C by tetrahydrofuran (TI(
F) has an intrinsic viscosity measured in the range of 0.03 to 2. OdJ/
g, more preferably 0.05 to 0.5 d
1! /g is essential. If the intrinsic viscosity is too low, it will cause a decrease in the physical properties of the coating film and worsen workability, while if it is too high, it will cause a decrease in solubility in the solvent.

In particular, if the intrinsic viscosity is too high, the finish of the coating will be poor and high coating film gloss cannot be obtained, which is not preferred as a coating resin.

In order to keep the intrinsic viscosity of the copolymer within the above range, the copolymerization reaction is carried out in the presence of a chain transfer agent. For example, JP-A-57-34108 proposes a copolymer containing fluoroolefins, cyclohexyl vinyl ether, and glycidyl vinyl ether as essential components, but these components have high polymerization reaction activity, resulting in a high degree of polymerization. The limiting viscosity exceeds the above range. Therefore, in the present invention, the problem is solved by carrying out the copolymerization reaction in the presence of a chain transfer agent such as trichlorofluoroethane or carbon tetrachloride in order to lower the intrinsic viscosity. However, if these chain transfer agents coexist, the chain transfer agents may remain in the product, which may impair the performance of the product.

Particularly in the solution polymerization method in which a copolymerization reaction is carried out in an organic solution, the polymerization solution is used as it is as a product such as a paint, so the contamination of these impurities is undesirable. - On the other hand, since glycidyl allyl ether, which is an essential component of the copolymer of the present invention, has a moderately high chain transfer ability, even if the polymerization reaction is carried out without the coexistence of other chain transfer agents, the above-mentioned A copolymer having a preferable intrinsic viscosity range can be easily obtained.

Examples of the fluoroolefins in the present invention include trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinyl fluoride, and vinylidene fluoride. Fluoroethylene is preferred.

Examples of fatty acid vinyl esters include vinyl acetate, vinyl lactate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl isocaproate, vinyl bivarisocate, vinyl caprylate, vinyl caprylate, vinyl caproic acid, Beover 9, Beover 10 (Shell Chemical Co., Ltd.) -!!, etc., but those in which the alkyl group has 1 to 12 carbon atoms are preferred.Fatty acid isopropenyl esters include isopropenyl acetate, isopropenyl propionate, etc. is preferred.

In addition, examples of the hydroxyalkyl allyl ether include allyl alcohol, ethylene glycol monoallyl ether, diethylene glycol monoallyl ether,
Examples include hydroxybutyl allyl ether, hydroxypropyl allyl ether, hydroxybutyl allyl ether, and hydroxyhexyl allyl ether.

In addition to the essential components of the fluoroolefins, fatty acid vinyl esters or fatty acid isopropenyl esters, allyl glycidyl ethers, and hydroxyalkyl allyl ethers of the present invention, other polymerizable comonomers include ethyl acrylate, methyl methacrylate, glycidyl methacrylate, etc. Examples include esters of acrylic acid or methacrylic acid, acrylamides such as acrylamide and N-methylolacrylamide, vinyl ethers such as ethyl vinyl ether and butyl vinyl ether, and carboxylic acids such as vinyl acetic acid and allyl acetic acid.

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

The copolymer of the present invention can be prepared in the presence of a conventional radical initiator.
It can be obtained by copolymerizing the monomers by methods such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk polymerization, but as mentioned above, it is not possible to provide the polymerization product as it is as a product such as a paint. Solution polymerization is an industrially superior production method.

The appropriate polymerization temperature for producing the copolymer is -30 to 100°C, preferably 0 to 70°C. Examples of the radical initiator include oil-soluble radical initiators such as diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, tertiary butyl peroxybivalate, di-2-ethylhexyl peroxydicarbonate, and benzoyl peroxydicarbonate. Peroxides such as oxide, lauroyl peroxide, perfluorooctanoyl peroxide, azoisobutyronitrile, azobis-2,4
-Ab compounds such as dimethylvaleronitrile, or organic boron compounds such as triethylboron-oxygen or peroxide.

The solvent is not particularly limited, but a conventional organic hydrocarbon compound, a fluorine-based organic compound, or a combination thereof can be used.

In the copolymerization reaction of the present invention, the pH value of the liquid during polymerization is 4 to IL.
Preferably, it needs to be in the range of 5 to 10. p
If the H value is lower or higher than this range, the glycidyl groups and hydroxyl groups may react and the product copolymer may gel.

In order to solve this problem, it is necessary to add a basic buffer to the polymerization solution. As the basic buffer, for example, sodium carbonate, potassium carbonate, magnesium carbonate, sodium borate, silica, celite, etc. can be used. The amount added can be determined as appropriate so that the pH value of the polymerization solution falls within the above range, but it is usually added in an amount of 0.05 to 5% by weight based on the total amount of monomers charged. be done.

The copolymer compound of the present invention contains an epoxy ring and a hydroxyl group as curing sites, and can be cured by adding amines, carboxylic acids, phenols, alcohols, etc. Furthermore, heating will further increase the curing rate.

In addition, pigments, ultraviolet absorbers, antioxidants, dispersion stabilizers, etc. may be added to the solution of this copolymer, and all of them exhibit good dispersibility.

In addition, the copolymer of the present invention includes cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbons such as benzene, toluene, and xylene, esters such as ethyl acetate and butyl acetate, ketones such as acetone and methyl ethyl ketone,
Nitrogen-containing solvents such as dimethylformamide and pyridine, 1.
1.1 Can be dissolved in halogen-containing solvents such as trichloroethane and trichloroethylene. Furthermore, the solutions obtained by dissolving them in these solvents are colorless and transparent in all cases.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 In a stainless steel autoclave with an internal volume of 0.51 and equipped with a magnetic stirrer, 51.6 g of vinyl acetate (VAc), 17.1 g of allyl glycidiether (AGE), and ethylene glycol monoallyl ether (EGMAE) 15.
3g.

Butyl acetate (BuAc) 150g, sodium carbonate 2
．． 0g, lauroyl peroxide (LPO) 1. og
The inside of the autoclave was replaced with nitrogen gas three times.

Then, the inside was degassed and chlorotrifluoroethylene (C
115.6 g of TFE) was introduced and the temperature was gradually raised. 60
After polymerization was carried out at ℃ for 24 hours, unreacted CTFE was removed and the autoclave was opened, and the solid content concentration was 58.
A 0 wt % copolymer solution was obtained. p of this copolymer solution
The H value was 6.0.

When this copolymer solution was reprecipitated with n-hexane, 154.5 g of a transparent solid copolymer shown in Table 1 was obtained. The intrinsic viscosity of this copolymer measured in THF at 30°C is 0.
23 dl/g, and the epoxy equivalent measured by direct titration of epoxy groups is 1386 g/eqiv,
The OH value measured by hydroxyl group titration method is 35.3 ■KOH/
It was g. In addition, the infrared absorption spectrum has 3530
cm-'-OH13050cm-'C-H11760cI11' of the methylene group of the terminal epoxy ring C=0
absorption was observed in each case. Furthermore, as a result of thermal analysis by DSC-TG, no melting point was observed, and the weight loss by TG started at 250°C or higher.

Example 2 Vinyl butyrate (VBu) in a similar manner to Example Nl 73.
0g, AGE 1B, 2g, EGMAE 16.3
g, CTFE 121.1g, xy 1y (XL)
140 g of potassium carbonate, 1.0 g of potassium carbonate, and 5,0 g of LPO were charged and reacted to obtain a copolymer solution with a solid content of 58%.

The pH value of this copolymer solution was 6.0. When this copolymer solution was reprecipitated with n-hexane, 168.2 g of a transparent solid copolymer shown in Table 1 was obtained. The intrinsic viscosity of this copolymer measured in THF at 30°C is 0.07 dl.
/g, epoxy equivalent is 1260g/aqiv, 01
One side was 32.3 rngKOH/g. In addition, in the infrared absorption spectrum, 3530 am publication, 3050 cm
Unique absorption similar to that in Example 1 was observed in each of the citrus fruits 1760aa-' and 1760aa-'.

Example 3 VBu 36.5g, 8GE 1 in the same manner as Example 1
8.2g, EGMAE 16.3g, CTFE 12
1.1g, BuAc 200g1 Beopa 10 (manufactured by Shell Chemical) mO) 63.4g, sodium carbonate 1.
5g and LPO2, Og were charged and reacted, solid content 55
% copolymer solution was obtained. The pH value of this copolymer solution was 565. When this copolymer solution was reprecipitated with n-hexane, a transparent solid copolymer 176 shown in Table 1 was obtained.
．． 1g was obtained. The intrinsic viscosity of this copolymer measured in THF at 30°C is 0.10 df/g, and the epoxy equivalent is 103
7g/eqiv, and the OH value was 28■KO)I/g. Also, in the infrared absorption spectrum, 3530C111
-', 3050CIl+-', and 1760ae-' had the same unique absorption as in Example 1, respectively.

(Hereinafter, blank space) - Table 1 Comparative Example 1 A reaction was carried out in the same manner as in Example 1, except that the amount of sodium carbonate was changed to 0.3 g, and all other amounts were kept the same. When the autoclave was opened after 24 hours, the contents gelled and the desired copolymer was not obtained. The pH value of the gelled product solution was 2.0.

Example 4 25 g of the copolymer obtained in Example 1 was mixed with 25 g of BuAc.
Hexamethylene diamine (HMDA) is added to a solution dissolved in
) and 1.9 g of BuAc solution was applied onto an aluminum plate and cured by heating at 140° C. for 30 minutes. As a result, a transparent coating film with good adhesion was obtained. Table 2 shows the physical properties of the resulting coating film.

Examples 5 to 7 100 parts of a 50% by weight xylene solution of each copolymer obtained in Examples 1 to 3 and Kneepan 205E-60 (Mitsui Toatsu ■
melamine resin) and 25 parts of melamine resin.
After adjusting the concentration by adding 00 (manufactured by Esso Kagaku ■, solvent), it was painted on an aluminum plate by a spray method and heated at 140°C for 30 minutes.
It was cured by heating for 0 minutes. As a result, a transparent coating film with good adhesion was obtained. Table 2 shows the physical properties of the resulting coating film.

(Hereafter, gong ω.

However, the ○ mark in the table indicates a state in which no change in surface shape was observed by visual inspection.

However, the mark ○ in the table indicates a state in which no change in surface shape was observed by visual inspection.

Example 8 The same liquid mixture as in Example 5 was applied onto a glass plate and cured by heating at 140° C. for 30 minutes, and then the coating was peeled off to obtain a colorless and transparent film with a thickness of 40 μm. Figure 1 shows the transmittance of this film to ultraviolet and visible light.

(Effects of the Invention) The fluorine-containing copolymer of the present invention contains CF bonds in its molecular chain, so it has excellent weather resistance and chemical resistance, and also contains ester groups, so it can be used for iron, aluminum, etc. It has excellent adhesion to surfaces, and since it contains an epoxy group and a hydroxyl group as curing sites, it can be cured by reacting with a compound having a functional group that reacts with an epoxy group or a hydroxyl group. Moreover, the resulting coating film is transparent, hard, and glossy, so it can be used not only as a baking paint for iron, aluminum, etc., but also for coating concrete, wood, etc.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the ultraviolet and visible light transmittance of the film.

Claims (6)

[Claims] (1) Fluoroethylene and formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R_1=H or CH_3, R_2=CnH_2n+
Fatty acid vinyl ester or fatty acid isopropenyl ester represented by _1n=an integer of 1 to 12), formula ▲ mathematical formula,
There are chemical formulas, tables, etc. ▼ Allyl glycidyl ether shown by and the formula CH_2=CH-CH_2-O
-R_3-OH(R_3=CnH_2n+_1n=0~
A copolymer containing as an essential component a hydroxyalkyl allyl ether (an integer of 5), which contains fluoroolefins, fatty acid vinyl esters or fatty acid isopropenyl esters, allyl glycidyl ethers, hydroxyalkyl allyl ethers, and other polymerizable copolymers. The content of monomer-based units is 25, respectively, in the resulting copolymer composition.
~75 mol%, 10-70 mol%, 3-70 mol%, 3
~40 mol%, and 0~20 mol%, and the intrinsic viscosity measured at 30°C in tetrahydrofuran is 0.03~
A curable fluorine-containing copolymer with a yield of 2.0 dl/g. (2) The fluorine-containing copolymer according to claim 1, wherein the fluoroolefin is chlorotrifluoroethylene. (3) The content of units based on fluoroolefins and fatty acid vinyl esters or fatty acid isopropenyl esters, allyl glycidyl ethers, hydroxyalkyl allyl ethers and other polymerizable comonomers is 25 to 25, respectively, in the resulting copolymer composition. A method for producing a fluorine-containing copolymer, characterized in that it is charged to a concentration of 75 mol%, 10 to 70 mol%, 3 to 40 mol%, and 0 to 20 mol%, and reacted at a reaction temperature of -30 to 100°C. . (4) Claim 3 characterized in that the polymerization is carried out in an organic solvent.
A method for producing the fluorine-containing copolymer described above. (5) The method for producing a fluorine-containing copolymer according to claim 3, wherein the pH value of the reaction solution during polymerization is in the range of 4 to 11. (6) The method for producing a fluorine-containing copolymer according to claim 3, characterized in that the pH value of the reaction solution during polymerization is adjusted by adding a basic buffer.