JPH04372612A - Production of hydroxylated fluoroolefin copolymer - Google Patents

Abstract

PURPOSE:To produce a hydroxyloted fluoroolefin copolymer in good reproducibility without causing gelation during polymerization or without remarkably increasing the dispersity. CONSTITUTION:A process for producing a hydroxylated fluoroolefin copolymer by using a floroolefin and a hydroxyated vinyl monomer as essential monomer components, wherein the monomer mixture is radical-polymerized in the presence of an amine and an alkali metal carbonate and/or an alkaline earth metal carbonate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hydroxyl group-containing fluoroolefin copolymer.

0002

BACKGROUND OF THE INVENTION Conventionally, fluorine-containing copolymers have been widely used in many fields because of their excellent heat resistance, mechanical properties, chemical resistance, weather resistance, etc. One of its uses is as a coating film-forming component for paints, and examples of fluorine-containing copolymers that are soluble in organic solvents and have hydroxyl groups that are particularly useful for paints include JP-A-57-34107. No., JP-A-61-275311, JP-A-61-57609, JP-A-62-17421
Copolymers of fluoroolefins and hydroxyl group-containing vinyl monomers that can be copolymerized with the fluoroolefins are known, as disclosed in No. 3 and JP-A-63-182312.

However, when producing such a hydroxyl group-containing fluoroolefin copolymer in an organic solvent, it is necessary to increase the amount of the hydroxyl group-containing vinyl monomer, increase the polymerized nonvolatile content, or increase the molecular weight of the copolymer. If you try to make the copolymer higher, it may gel during polymerization or the dispersion ratio (ratio of weight average molecular weight to number average molecular weight) of the resulting copolymer may become significantly large, making it difficult to produce the desired copolymer with good reproducibility. The problem is that it cannot be done. As a method to solve this problem, for example, Japanese Patent Application Laid-Open No. 62-29281
As seen in Publication No. 3, etc., a method for producing a hydroxyl group-containing fluoroolefin copolymer in the presence of amines has been proposed, but it is difficult to reproducibly produce the desired copolymer using a method using such amines alone. In order to produce a good product, it is necessary to use a large amount of amines, which may result in significant discoloration during polymerization, decrease in physical properties such as adhesion to substrates, etc. It has a major drawback in that it also causes significant coloring.

0004

SUMMARY OF THE INVENTION The present invention is directed to a method for producing a hydroxyl group-containing fluoroolefin copolymer that solves the problems of the prior art, that is, gelling during polymerization,
The purpose of this invention is to provide a method for producing a desired hydroxyl group-containing fluoroolefin copolymer with good reproducibility without significantly increasing the dispersion ratio.

[0005]

[Means for Solving the Problems] As a result of intensive research in view of the above points, the present inventors have found that the above problems can be solved by using amines and carbonates of alkali metals and/or alkaline earth metals in combination. The inventors have discovered that the problem can be solved, and have completed the present invention. That is, in the present invention, when producing a fluoroolefin copolymer containing a hydroxyl group in an organic solvent using a fluoroolefin and a vinyl monomer containing a hydroxyl group as essential monomer components, the monomer mixture is mixed with an amine. , and a method for producing a fluoroolefin copolymer containing a hydroxyl group, which is characterized by carrying out radical polymerization in the presence of an alkali metal and/or alkaline earth metal carbonate.

The present invention will be explained in detail below. Typical examples of amines used in the present invention include vinyl monomers, which were discovered by the present inventors to introduce groups with antioxidant ability into the side chains of fluorine-containing copolymers. That is, these include 4-(meth)acryloyloxy-2,
2,6,6-tetramethylpiperidine, 4-(meth)
Acryloyloxy-1,2,2,6,6,-pentamethylpiperidine, 4-allyloxy-2,2,6,6,
-tetramethylpiperidine, 4-allyloxy-1,2
,2,6,6,-pentamethylpiperidine, vinyl-9
-2,2,6,6-tetra-substituted piperidinyl group such as -aza-3-ethyl-8,8,9,10,10-pentamethyl-1,5-dioxaspiro[5,5]-3-undecylmethyl ether Containing vinyl monomers can be mentioned. Furthermore, diethylamine, dipropylamine, N-methylbenzylamine, N,N-dimethylbenzylamine, dimethylcyclohexylamine, dimethylethanolamine, triethanolamine, triethylamine, tributylamine, pyrrolidine, piperidine, 1-methylpiperidine, 2 , 2,6,6-tetramethylpiperidine, 4-
Examples include hydroxy-2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, and the like.

Among these, the vinyl monomer containing a 2,2,6,6-tetra-substituted piperidinyl group not only acts as a stabilizer during polymerization, but also acts as a stabilizer in the side chain of the fluorine-containing copolymer after polymerization. It is most preferred because it is introduced as an antioxidant and storage stabilizer. These amines may be used alone or in combination of two or more.

The amount of the above-mentioned amines to be used is 0.0001 to 0.02 equivalent, preferably 0.001 equivalent, per 1000 g of the total amount of monomers to be copolymerized, in terms of basic nitrogen atoms contained in the amines. It is desirable that the amount is 0.01 equivalent. If the amount is less than 0.0001 equivalent, gelation may occur during polymerization, or the resulting copolymer may have a large dispersion ratio. On the other hand, if the amount exceeds 0.02 equivalent, coloration during polymerization becomes significant, and when formed into a coating film, various physical properties such as adhesion to a substrate deteriorate, and coloration over time is also extremely undesirable.

[0009] Examples of carbonates of alkali metals or alkaline earth metals used in the present invention include sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium carbonate, magnesium carbonate, barium carbonate, etc. Of these, sodium carbonate and potassium carbonate are most effective and suitable as stabilizers during polymerization when used in combination with the amines.

These alkali metal or alkaline earth metal carbonates may be used alone or in combination of two or more. The amount of alkali metal and/or alkaline earth metal carbonate used in the present invention is usually 0.1 to 10 parts by weight per 100 parts by weight of the monomer mixture.
Parts by weight, preferably from 0.5 to 5 parts by weight.

[0011] When producing a hydroxyl group-containing fluoroolefin copolymer in an organic solvent, gelation may occur during polymerization, or the dispersion ratio (ratio of weight average molecular weight to number average molecular weight) of the resulting copolymer may become significantly large. (e.g. 5 or more),
The cause of the inability to produce the desired copolymer with good reproducibility has not yet been fully elucidated. However, the present inventors discovered that an acid component is generated from the fluoroolefin during radical polymerization, and this acid component acts as a catalyst to promote the etherification reaction (crosslinking reaction) between hydroxyl groups, which may eventually lead to gelation. I'm guessing it's closed. In this case, amines alone can be used as a polymerization stabilizer (
When used as a neutralizing agent for the acid produced, amines are required in excess of the acid components produced, so the amount of amines used is inevitably large, which causes deterioration of various properties of the coating film. becomes. However, when amines and carbonates of alkali metals and/or alkaline earth metals are used together as polymerization stabilizers in an organic solvent, the carbonates of alkali metals and/or alkaline earth metals in the solid phase are mixed in the organic phase. The use of a small amount of amines not only acts effectively as a polymerization stabilizer, but also acts on the amines that have undergone a neutralization reaction with the acid component to regenerate unneutralized amines. It can be assumed that Japanese salt does not precipitate in the system.

[0012] Next, the fluoroolefin component used in the present invention has the general formula (a).

0013
]

[Chemical formula 1]

The following is used. Specific examples of such vinyl monomers include, for example,

[0015]

[Case 2]

Fluoroethylene series such as [0016]

[0017]

[Chemical formula 3]

Fluoropropene series such as;

[0019]

[C4]

Among these, (a'
)formula

[0021]

[C5]

Fluoroethylene compounds and fluoropropene compounds represented by the following are preferred, and tetrafluoroethylene (CF2=CF2), chlorotrifluoroethylene (CF2=CFCl) and hexafluoropropene (CF2=CFCF3) are particularly preferred. These fluoroolefins may be used alone or in combination of two or more.

The hydroxyl group-containing vinyl monomer used in the present invention has the general formula (b).

[0024]

[C6]

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

In the method for producing a hydroxyl group-containing fluoroolefin copolymer according to the present invention, in addition to the above-mentioned essential monomer components, other vinyl monomers that can be copolymerized with these essential monomer components are used. can be used as needed. Examples of such other vinyl monomers include olefins such as ethylene, propylene, and isobutylene;
Haloolefins such as vinyl chloride and vinylidene chloride, vinyl acetate, vinyl n-butyrate, vinyl benzoate, pt-
Vinyl carboxylate esters such as vinyl butyl benzoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl versatate, vinyl laurate, isopropenyl carboxylate esters such as isopropenyl acetate and isopropenyl propionate, ethyl vinyl ether , propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether,
Chain alkyl vinyl ethers such as neopentyl vinyl ether, 2-ethylhexyl vinyl ether, and octyl vinyl ether; fluorovinyl ethers such as pentafluoroethyl vinyl ether and 2-perfluorooctyl ethyl vinyl ether; cycloalkyl vinyl ethers such as cyclopentyl vinyl ether and cyclohexyl vinyl ether; phenyl Aryl vinyl ethers such as vinyl ether, aralkyl vinyl ethers such as benzyl vinyl ether and phenethyl vinyl ether, aromatic vinyl compounds such as styrene and vinyltoluene, allyl formate, allyl acetate, allyl butyrate, allyl benzoate, allyl cyclohexanecarboxylate, allyl cyclohexylpropionate Allyl esters such as allyl ethyl ether, allyl phenyl ether, butyl (meth)acrylate, methyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, perfluoromethyl (
meth)acrylate, perfluoropropyl(meth)acrylate, perfluoropropyromethyl(meth)acrylate, perfluoromethylmethyl(meth)acrylate, 2-perfluorooctylethyl(meth)acrylate, perfluoroisononylmethyl(meth)acrylate Acrylic acid or methacrylic acid esters such as acrylates, acrylamides such as acrylamide, N-methylol acrylamide, etc., as shown in Japanese Patent Application No. 1-237122, in which a cyclic hydrocarbon group is introduced via a urethane bond. Examples include vinyl monomers such as these, and endocyclic vinyl ethers shown in Japanese Patent Application No. 101695/1999.

Among these, vinyl monomers having a cyclic hydrocarbon group introduced through a urethane bond as shown in Japanese Patent Application No. 1-237122, and Japanese Patent Application No. 2-1016
The fluoroolefin copolymer using an endocyclic vinyl ether as disclosed in Japanese Patent No. 95 is suitable because it has excellent compatibility with a curing agent, hardness, and gloss. These vinyl monomers may be used alone or in combination of two or more.

[0028] When producing a hydroxyl group-containing fluoroolefin copolymer by the method of the present invention, the ratio of each monomer component used is 10 to 80% of the fluoroolefin from the viewpoint of yield and weather resistance of the copolymer. mol%, hydroxyl group-containing vinyl monomer 2 to 50 mol%, other copolymerizable vinyl monomers 0 to 60 mol%, preferably fluoroolefin 20 to 60 mol%, hydroxyl group-containing vinyl monomer 5 to 30 mol%
mol%, other copolymerizable vinyl monomers 5-50 mol%
managed by

In carrying out the method for producing a hydroxyl group-containing fluoroolefin copolymer of the present invention, the polymerization is carried out in the presence of an organic solvent using a predetermined proportion of vinyl monomers, including a fluoroolefin and a hydroxyl group-containing vinyl monomer as essential components. the mixture,
Copolymerization can be carried out in the presence of amines and carbonates of alkali metals and/or alkaline earth metals, using a polymerization initiator, ionizing radiation, or the like as a polymerization initiation source.

As the polymerization initiator, oil-soluble ones are preferably employed, such as azobisisobutyronitrile, 2
, 2'-azobis-(2,4-dimethylvaleronitrile) and other azo compounds, t-butylperoxypivalate,
Peroxy ester type peroxides such as t-butylperoxyisobutyrate, diacyl peroxide type peroxides such as octanoyl peroxide and lauroyl peroxide, and dialkyl peroxydicarbonate type peroxides such as diisopropyl peroxydicarbonate. Examples include dialkyl peroxide type peroxides such as oxides and benzoyl peroxide.

The amount of these polymerization initiators to be used is appropriately selected depending on the type thereof, copolymerization reaction conditions, etc., but is preferably 0.005 to 5% by weight, based on the total amount of monomers normally used. It is selected in a range of 0.05 to 0.5% by weight. Regarding the polymerization method, from the viewpoints of not requiring separation from the polymerization medium when making a paint, and stability of the polymerization reaction operation, etc.
It is important to use a solution polymerization method using an organic solvent such as a lower alkyl-substituted benzene such as xylene or toluene, an ester such as butyl acetate, or a ketone such as methyl isobutyl ketone.

[0032] There is no particular restriction on the polymerization type, and any of the batch type, semi-continuous type, and continuous type can be used. The reaction temperature in the copolymerization reaction is usually -30 to
+150°C, appropriately selected depending on the polymerization initiation source and polymerization medium, usually 0 to 100°C, preferably 10°C.
The temperature is selected within the range of ~90°C. Further, the reaction pressure is not particularly limited, but is selected within the range of normal pressure to 100 kg/cm2. Furthermore, the copolymerization reaction can be carried out by adding a suitable chain transfer agent.

The copolymer thus obtained is as it is,
Or curing agents, pigments, fillers, etc. that can react with hydroxyl groups,
It can be used in various applications such as paints, sealants, and films by adding curing catalysts and the like.

[0034]

[Example] Hereinafter, it will be explained in more detail with examples.
The present invention is not limited in any way by these examples. (2) Molecular weight of various resins: Determined from polystyrene standard calibration curve using gel permeation chromatography.

(Equipment used) Equipment: Shimadzu L
C-3A column: Tosoh Corporation TSKgel G-5000 HXLTSKgel
G-4000 HXLTSKgel G-20
00 HXL detector: Shimadzu RID-6A Data processing: Shimadzu C-R4A Carrier: Tetrahydrofuran ■Hydroxyl value: Measured according to JIS K-0070. (2) Color number (APHA color): Measured according to ASTM D1209.

[0036]

[Example 1] 7.7 g of potassium carbonate was charged into a stainless steel autoclave having an internal volume of 1 liter and equipped with a stirrer, and the inside of the autoclave was purged with nitrogen gas three times. Then, 4-methacryloyloxy-1,2,2,6,6
, -0.48 g of pentamethylpiperidine, 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- as an initiator. Butyl peroxypivalate 1.7
g was charged, and polymerization was carried out at 67°C for 8 hours. Potassium carbonate is removed by filtration from the copolymer solution produced, and APHA
A copolymer solution with a color rating of 10 and a nonvolatile content of 50.6% was obtained.

The number average molecular weight of the obtained copolymer was 10,
600, the dispersion ratio (ratio of weight average molecular weight to number average molecular weight) was 3.6, the fluorine content was 22.2%, and the hydroxyl value was 52 mgKOH/g.

[0038]

[Example 2] 7.7 g of sodium carbonate was charged into a stainless steel autoclave having an internal volume of 1 liter and equipped with a stirrer, and the inside of the autoclave was purged with nitrogen gas three times. Then, 0.15 g of N,N-dimethylbenzylamine,
23 g of 4-hydroxybutyl vinyl ether, 2,3-
21 g of dihydrofuran, 50 g of isobutyl vinyl ether
g, 117 g of chlorotrifluoroethylene, 211 g of butyl acetate, and 1.7 g of t-butyl peroxypivalate as an initiator were charged, and polymerization was carried out at 67° C. for 8 hours. Sodium carbonate was removed by filtration from the copolymer solution produced, and the APHA color rating was 50 and nonvolatile content was 49.8.
% copolymer solution was obtained.

The number average molecular weight of the obtained copolymer was 9.7.
00, the dispersion ratio (ratio of weight average molecular weight to number average molecular weight) was 2.8, the fluorine content was 27.2%, and the hydroxyl value was 53 mgKOH/g.

[0040]

[Example 3] N,N-dimethylbenzylamine 0.15
The reaction was carried out in the same manner as in Example 2 except that 0.15 g of 2,2,6,6-tetramethylpiperidine was used instead of g, and the APHA color rating was 20 and the nonvolatile content was 49.6.
% copolymer solution was obtained. The number average molecular weight of the obtained copolymer was 9,900, the dispersion ratio (ratio of weight average molecular weight to number average molecular weight) was 2.8, and the fluorine content was 27.2%.
, and the hydroxyl value was 53 mgKOH/g.

[0041]

[Comparative Example 1] A reaction was carried out in the same manner as in Example 1 except that 7.7 g of potassium carbonate was not used, and a jelly-like gelled product was produced.

[0042]

[Comparative example 2] 4-methacryloyloxy-1,2,2,
The reaction was carried out in the same manner as in Example 1 except that 0.48 g of 6,6,-pentamethylpiperidine was not used. The number average molecular weight of the obtained copolymer was 13,900, and the dispersion ratio (weight average The ratio of molecular weight to number average molecular weight) is 6.3
and the hydroxyl value is 37mgKOH/g, which is the set value (
53mgKOH/g).

[0043]

[Comparative Example 3] A reaction was carried out in the same manner as in Example 2 except that 7.7 g of potassium carbonate was not used, and a jelly-like gelled product was produced.

[0044]

[Comparative Example 4] N without using 7.7g of potassium carbonate,
When the reaction was carried out in the same manner as in Example 2 except that the amount of N-dimethylbenzylamine used was increased from 0.15 g to 1.5 g, the resulting copolymer solution was significantly colored (AP
HA color score of 300 or higher).

[0045]

[Comparative Example 5] 2, without using 7.7g of potassium carbonate
The amount of 2,6,6-tetramethylpiperidine used was 0.1
When the reaction was carried out in the same manner as in Example 3 except that the amount was increased from 5 g to 1.5 g, the resulting copolymer solution contained 2, 2, 6
, 6-tetramethylpiperidine and an acid, resulting in significant turbidity.

[0046]

[Reference example] Using the hydroxyl group-containing fluoroolefin copolymer solution obtained in Example 1 as the main ingredient, "Duranate TPA" (manufactured by Asahi Kasei Industries, Ltd.) as a curing agent was used as a NCO/OH
After blending so that the ratio was 1/1, xylene was used as a thinner and the time was adjusted to 15 seconds using Ford Cup #4, and painting was performed. The obtained coating film was baked at 120°C for 1 hour, and J
Based on IS K-5400 Angle of incidence: 60
When the coating gloss was determined at 100 °C, a cured coating film with a gloss of 85% and a good appearance was obtained. This coating film was exposed to a sunshine weather meter for 3,000 hours, but showed good weather resistance with almost no decrease in gloss.

[0047]

Effects of the Invention As is clear from the above results, the monomer mixture containing the fluoroolefin and the hydroxyl group-containing vinyl monomer according to the present invention as essential components can be used with amines and alkali metals and/or alkaline earths. The method of producing a fluoroolefin copolymer containing a hydroxyl group by radical polymerization in an organic solvent in the presence of a metal carbonate is a method that prevents gelation during polymerization and dispersion ratio (weight average molecular weight and In addition to effectively suppressing the increase in the ratio (to the number average molecular weight), the paint based on the hydroxyl group-containing fluoroolefin copolymer obtained by the production method of the present invention has excellent weather resistance. Provides a coating film.

Therefore, the method of the present invention provides an excellent hydroxyl group-containing fluoroolefin copolymer that can be used in various applications such as paints, sealants, and films.

Claims (1)

[Claims] Claim 1: When producing a fluoroolefin copolymer containing a hydroxyl group in an organic solvent using a fluoroolefin and a vinyl monomer containing a hydroxyl group as essential monomer components, the monomer mixture is mixed with an amine. and radical polymerization in the presence of an alkali metal and/or alkaline earth metal carbonate.