JPS6213419A - Production of alpha, beta-unsaturated dicarboxylic acid anhydride polymer - Google Patents

Abstract

PURPOSE:To obtain the title polymer stably in good yields and efficiency by preventing the deposition of polymer on the wall and the like areas of a polymerization kettle, by radicalpolymerizing an alpha, beta-unsaturated dicarboxylic acid anhydride in the presence of a specified dispersant and a poor solvent. CONSTITUTION:100pts.wt. monomer (mixture) comprising an alpha, beta-unsaturated dicarboxylic acid anhydride (e.g., maleic anhydride) and, optionally, 0-30mol% other copolymerizable monomers such as linear or cyclic monoolefins is (co) polymerized in a state of suspension at 70-200 deg.C for 2-12hr by using 1-30pts. wt. radical initiator such as an organic peroxide in the presence of 0.5-10pts.wt. dispersant comprising an ethylene/vinyl ester copolymer, etc., of a vinyl ester content >=5wt% and a MI >=5g/10min and a poor solvent (e.g., pentane).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a t,β-unsaturated dicarboxylic acid anhydride polymer, and more specifically, the present invention relates to a method for producing a t,β-unsaturated dicarboxylic acid anhydride polymer. This invention relates to a method for polymerizing saturated unsaturated dinorphonic anhydride.

(Prior Art) Polymers of α,β-unsaturated dicarboxylic acid anhydrides (hereinafter sometimes referred to as polydicarboxylic acids) represented by maleic anhydride can be used as a polymer itself or in the form of alkali metal salts, ammonium salts, and esters. It is known to be used in the fields of epoxy curing agents, ink and adhesive additives, dye and pigment dispersants, detergent builders, textile treatment agents, water treatment agents, etc. in the form of chemical compounds.

It is known that such polydicarboxylic acids are generally obtained by dissolving α, β-, β-dicarboxylic acid anhydride in an inert organic solvent and polymerizing it using a radical polymerization catalyst. For example, according to Japanese Patent Publication No. 55-20475, maleic anhydride is polymerized using toluene as a solvent and benzoyl peroxide as an initiator for at least 3 hours at 70 to 120"C. Polymaleic anhydride is obtained in high yield.

However, in such conventional methods, the product precipitates from the bath liquid as a black colored tar-like substance, as is clear from Example 7. Therefore, the purification method is complicated, and the troublesome operation of heating and dissolving the tar-like material in a small amount of methyl ethyl ketone, precipitating the polymer with a large amount of toluene, and then separating the product is carried out.

In addition to complicating the purification process, there are other problems caused by the tarry nature of the product, such as the large amount of energy required for stirring, clogging of the equipment, and polymer buildup on the walls of the vessel. There were problems such as the occurrence of adhesion and the mixing of unreacted maleic anhydride into the product, resulting in a decrease in conversion rate.

(Problems to be Solved by the Invention) Therefore, the present inventors have attempted to solve these drawbacks of the prior art (
As a result of intensive research, it was discovered that by using a specific dispersant, polydicarbonate H'x could be produced not as a tar-like substance (but as a streaky powder), and based on this knowledge, the present invention was completed. .

(Another means to solve the problem) According to the present invention, in the presence of an ethylene-vinyl ester copolymer and a poor solvent,
Provided is a method for producing an α,β-unsaturated dicarboxylic anhydride polymer, which comprises radically polymerizing a saturated dicarboxylic anhydride.

The α,β-unsaturated dicarboxylic acid anhydride used as a monomer in the present invention may be any one commonly used in this technical field, and specific examples thereof include maleic anhydride, itaconic anhydride, Examples include those having 4 to 10 carbon atoms, such as acids and citraconic anhydride. Among these, maleic anhydride is prized for its reactivity, quality, and economy.

These monomers may be used in combination with two or more polymers if necessary (and other comonomers that can be copolymerized may be used in combination within a range that does not essentially change the performance of the product). You can also do it.

Specific examples of comonomers that can be used in combination include ethylene,
Propylene, Isobutyne, Butene-1, Butene-2, Pentene-1, Pentene-2,2-Meterbutene-1,2
- Chain monoolefins such as methylbutene-2, hexene-1,2,2,4-trimethylpentene-1,2,2,4-trimethylpentene-2, decene-1, etc.
Examples include monoolefins such as cyclopentene, cyclohexene, and cyclooctene, and aromatic monoolefins such as styrene, α-methylstyrene, and vinyltoluene. is used at a molar value of 20 or less.

The polymerization of the present invention is carried out in a poor solvent in the presence of a specific dispersant, namely an ethylene-vinyl ester copolymer.

The dispersant used has a vinyl ester content of 5 f[
% or more, preferably 10 to 50% by weight, and melt index (M engineering, ASTM D-1238) Z>' 5.5
' / IQ min or more, preferably 10-100
The vinyl ester, which is the monomer component of this ethylene-vinyl ester copolymer, is vinyl acetate, 10
It is a vinyl ester of a carboxylic acid having an alkyl group having 1 to 4 carbon atoms, such as vinyl pionate, vinyl butyrate, and vinyl pionate, among which vinyl acetate is also prized.

The amount of the dispersant used is usually 0.5 to 10 parts by weight, preferably 1.0 to 53 parts by weight per 100 parts by weight of the monomer component.
ft part, and if the amount used is small, the effect of suppressing the production of oily substances is small (on the contrary, if the amount used is large, it is economically disadvantageous).

Furthermore, in the present invention, a poor solvent, that is, a solvent that does not dissolve the produced polymer, is used as the polymerization solvent. Specific examples of such poor solvents include linear, branched or cyclic aliphatic hydrocarbons such as butane, pentane, hexane, hegetane, octane, decane, ligroin, cyclohexane, etc., benzene, toluene, xylene, Examples include aromatic hydrocarbons such as chlorobenzene.

In the present invention, polymerization is carried out according to a conventional method in the presence of the above-mentioned poor solvent and dispersant.

Catalysts used in the reaction include cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, benzoyl peroxide, diinferroyl peroxydicarbonate, t-butyl peroxybivalate, etc. Radical initiators such as organic peroxides, azobis compounds such as α, α′-azobisisobutyronitrile, α, α′-azo α-ethylbutyronitrile, redox catalysts, etc. If so, there are no particular restrictions. The amount of such a catalyst used is usually 1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of monomer components. Polymerization is usually carried out at 70 to 200°C, preferably 90 to 150°C.
It is applied in suspension at 0.degree. C. for 2 to 12 hours.

(Effects of the Invention) Thus, according to the present invention, the problems associated with the production of oily substances as described above can also be solved. In other words, it is possible to operate stably for a long period of time without having to thoroughly clean the polymerization reactor, and it is possible to obtain polymers with high yield and efficiency. It is possible to transfer, separate, wash, and
Purification etc. become easier, and the manufacturing process can be simplified.

(Example) The present invention will be described in more detail with reference to Examples below. In addition, parts and weights in the examples are based on weight unless otherwise specified, and the types of ethylene-vinyl ester copolymers used in the examples are as shown in Table 1.

Table 1 Book 1 Ethylene-vinyl acetate copolymer umbrella 2 manufactured by Mitsui Polychemical Co., Ltd. Ethylene-vinyl acetate copolymer manufactured by Sumitomo Chemical Co., Ltd. Example 1 196 parts of maleic anhydride was placed in a 31 autoclave equipped with a stirrer, After sealing the can and then purging the system with gold and nitrogen, adding 1000 parts of leupentane under reduced pressure, raising the temperature to 130°C, and adding the ethylene-vinyl acetate copolymer shown in Table 1 as a dispersant at the same temperature. 4.5 parts of (I) to (V) and 25 parts of di-t-butyl oxide were added over 1 hour. Thereafter, polymerization was carried out by heating and stirring at the same temperature for 6 hours. After the polymerization reaction was completed, the produced polymer was extracted from a valve at the bottom of the polymerization vessel, and its conversion rate was measured.

In addition, the situation inside the polymerization system and the occurrence of clogging of the bottom valve f: were observed. The results are shown in Table 2.9 Table 2 The conversion rate was measured using a high performance liquid chromatograph.
Conversion rate of maleic anhydride measured and calculated by measuring unreacted maleic anhydride After that,
55 parts of Pentene-1 and 120 parts of Lupentane under reduced pressure
After adding 1,300 parts of toluene ft, the temperature was raised to 150°C, and at the same temperature, 9 parts of ethylene-vinyl acetate co-monomer (Irl) shown in Table 1 and di-t were added as a dispersant.
-50 parts of butyl peroxide were added over 1 hour. Thereafter, the mixture was heated and stirred at the same temperature for 6 hours to effect polymerization.

As a result, the conversion rate was 75%, and the product was a yellow powder slurry. Further, there was no clogging of the bottom pulp, and no oily substance was observed after the slurry was extracted.

Claims (1)

[Claims] 1. Production of α,β-unsaturated dicarboxylic acid anhydride polymer, which is characterized by radical polymerization of α,β-unsaturated dicarboxylic acid anhydride in the presence of an ethylene-vinyl ester copolymer and a poor solvent. Law.