JP2000026508A - Production of alkkylvinyl ether-maleic anhydride copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing an alkylvinyl ether- maleic anhydride copolymer useful for raw materials for adhesives and the like in high purity without allowing the polymer to coagulate or stick to the reactor by precipitably polymerizing a specific alkylviny; ether with maleic anhydride in a specific solvent. SOLUTION: The method is conducted by polymerizing (A) an alkyl vinyl either (e.g. ethyl vinyl ether) of the formula: CH2=CH-OR (R is 2-4C alkyl) with (B) maleic anhydride by using pref. >2 mol. of component a based on 1 mol. of component B input for polymerization, in a mixed solvent containing (C) an aliphtatic ketone e.g. diisobutyl ketone and having the weight ratio of C to A of (80 to 20) to (40 to 60) after polymerized, at generally 30 to 100 deg.C under the atmospheric pressure or raised pressures, thus obtaining the resultant polymer having a weight average molecular weight pref of to 200,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an alkyl vinyl ether-maleic anhydride copolymer.

[0002] Alkyl vinyl ether-maleic anhydride copolymers are useful substances as raw materials for pressure-sensitive adhesives, adhesives and paints.

[0003]

BACKGROUND OF THE INVENTION It is known that alkyl vinyl ethers are polymerized with maleic anhydride in the presence of a radical initiator to give an alkyl vinyl ether-maleic anhydride copolymer.

The method for producing the alkyl vinyl ether-maleic anhydride copolymer includes, for example, (i) a solution polymerization method using methyl acetate, ethyl acetate, acetone and methyl ethyl ketone as a solvent, and (ii) benzene, toluene, xylene and the like. Aromatic hydrocarbons; aliphatic hydrocarbons such as hexane, heptane, and octane; halogenated aliphatic hydrocarbons such as dichloroethane, trichloroethane, and carbon tetrachloride; and precipitation polymerization using methyl isopropyl acetate propionate as a solvent. Are known.

[0005] However, the method (i) has a problem that the viscosity is extremely increased at a high polymer concentration, stirring becomes difficult, and a large amount of energy is required to completely remove the solvent. there were.

In the method (ii), only a method of polymerizing at a low polymer concentration of about 20% by weight or less is disclosed.
In addition, only a fine suspension of the polymer is obtained. If the concentration is higher than that, there is a problem that the production efficiency is extremely reduced, such as aggregation of the polymer and sticking of the polymer to the reaction vessel.

[0007]

As an attempt to solve these problems, Japanese Patent Publication No. 2610962 proposes a method using an excess amount of a mixed solvent of alkyl vinyl ether and acetone. However, this method is a solution polymerization method, and is not suitable for the purpose of extracting an alkyl vinyl ether-maleic anhydride copolymer with high purity.

Japanese Patent Application Laid-Open No. 5-186533 discloses that
A polymerization method using a branched aliphatic ketone having 6 to 7 carbon atoms other than a linear ketone or an aliphatic ketone having 8 or more carbon atoms as a solvent is disclosed. However, this method is suitable when the alkyl vinyl ether is methyl vinyl ether.However, when the alkyl group of the alkyl vinyl ether is an alkyl vinyl ether having a larger number of carbon atoms than the methyl group, the suppression of aggregation becomes insufficient or the high molecular weight It was difficult to get a body.

The present invention has been made to solve the above-mentioned problems, and a copolymer of an alkyl vinyl ether having an alkyl group having 2 to 4 carbon atoms and maleic anhydride can be produced at a high polymer concentration. The high-molecular-weight alkyl vinyl ether can be obtained efficiently and with high purity without causing agglomeration or sticking to a vessel wall of a reaction vessel or the like.
An object of the present invention is to provide a method for producing a maleic anhydride copolymer with high productivity.

[0010]

Means for Solving the Problems The present inventors have solved the above-mentioned problems and have efficiently produced a copolymer of a high molecular weight alkyl group having 2 to 4 carbon atoms of an alkyl vinyl ether and maleic anhydride. As a result of examining the method of performing the above, the alkyl vinyl ether and maleic anhydride are subjected to precipitation polymerization in a mixed solvent of a specific ratio consisting of an aliphatic ketone and an alkyl vinyl ether, so that the obtained polymer may be agglomerated or fixed to the reaction vessel. It does not occur, and it is found that the polymerization reaction can be performed at a high polymer concentration, and by changing the amount of alkyl vinyl ether with respect to the aliphatic ketone in the mixed solvent, the molecular weight can be controlled, and the case where only the aliphatic ketone is used as the solvent is used. Have found that a much higher molecular weight copolymer can be obtained, and have completed the present invention.

The present invention provides an alkyl vinyl ether represented by the following general formula (1): CH ₂ ＣＨCH—OR (R is an alkyl group having 2 to 4 carbon atoms) and maleic anhydride, and an aliphatic ketone. When the precipitation polymerization is carried out in a solvent containing the solvent, the vinyl ether present in the solvent after the polymerization is expressed in terms of a weight ratio to the aliphatic ketone: aliphatic ketone / vinyl ether = 80/2
The present invention relates to a method for producing an alkyl vinyl ether-maleic anhydride copolymer, which is characterized by being polymerized so as to be 0 to 40/60.

From the viewpoint of increasing the molecular weight, it is preferable to use the alkyl vinyl ether in a range of more than 2 mol per 1 mol of the maleic anhydride at the time of the polymerization.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The alkyl vinyl ether used in the present invention may be a compound represented by the above general formula (1), specifically, ethyl vinyl ether,
Examples thereof include isopropyl vinyl ether, normal propyl vinyl ether, isobutyl vinyl ether, and normal butyl vinyl ether, and a mixture thereof can also be used.

The polymerization according to the present invention is initiated by a conventional radical generator. As the initiator, any commonly used initiator can be used. Among them, 2.2′-azobisisobutyronitrile, 2.2′-azobis (4-
Methoxy-2,4-dimethylvaleronitrile);
2′-azobis (2,4-dimethylvaleronitrile),
2.2 Azo compounds such as 2'-azobis (2-methylbutyronitrile), lauroyl peroxide, benzoyl peroxide, t-butylperoxyneodecanate, t-butylperoxypivalate, t-butylperoxy Organic peroxides such as -2-ethylhexanoate, t-butylperoxybenzoate, methyl ethyl ketone peroxide and dicumyl peroxide can be suitably used.

The amount of initiator used is between 5.0 and 0.001%, preferably between 1.0 and 0.01% of the maleic anhydride used for the copolymerization.

The proportions of the alkyl vinyl ether and maleic anhydride may be equimolar, but it is preferable to use an amount exceeding 2 moles of alkyl vinyl ether per mole of maleic anhydride at the time of polymerization. It is preferred in terms of.

[0017] The solvent used in the present invention is a solvent containing an aliphatic ketone.
-Methyl-3-heptanone, 2-methyl-4-heptanone, 5-methyl-3-heptanone, 6-methyl-2-heptanone, 2-nonanone, 3-nonanone, 4-nonanone, 5-nonanone, 5-methyl -2-octanone, diisobutyl ketone, 2-decanone, 3-decanone and 4-decanone are preferred, and diisobutyl ketone is particularly preferred.

In the present invention, the solvent at the end of the polymerization may be an aliphatic ketone and an alkyl vinyl ether, wherein the aliphatic ketone / alkyl vinyl ether = 80/20 to 40/60.
It is sufficient that the mixed solvent is contained in a ratio within the range of (weight ratio).
The alkyl vinyl ether in the mixed solvent may be the same as or different from the alkyl vinyl ether used in the reaction. When one kind of alkyl vinyl ether is copolymerized with maleic anhydride, the same alkyl vinyl ether to be reacted with the alkyl vinyl ether used as a solvent is used. It is presumed that the effect of the mixed solvent appears when an aliphatic ketone that hardly dissolves the copolymer and an alkyl vinyl ether that can solvate the copolymer are mixed in a well-balanced manner.

The mixing ratio of the aliphatic ketone and the alkyl vinyl ether in the solvent at the end of the weight varies depending on the type of the aliphatic ketone and the alkyl vinyl ether used and the desired molecular weight of the copolymer. / 20 to 40/60 (weight ratio). The ratio of the aliphatic ketone is 80/2 by weight.
If it is larger than 0, it becomes difficult to completely consume the maleic anhydride. If the proportion of the aliphatic ketone is less than the above-mentioned weight ratio of 40/60, the copolymer will agglomerate or adhere to the vessel wall of a reaction vessel or the like, making it difficult to carry out the polymerization reaction at a high polymer concentration. In order to increase the molecular weight of the copolymer, the alkyl vinyl ether in the mixed solvent may be replaced with an aliphatic ketone / alkyl vinyl ether = 80/20.
The amount may be increased within a range of 40/60 (weight ratio).

In the present invention, the charge concentration of the alkyl vinyl ether and the maleic anhydride is preferably set so that the obtained copolymer solid content concentration is 20 to 40% by weight.

The copolymerization according to the present invention is carried out by a conventional method. Alkyl vinyl ether and maleic anhydride may be charged into a solvent at once and copolymerized, or both or either of alkyl vinyl ether and maleic anhydride may be added sequentially or dividedly for copolymerization.

The copolymerization reaction according to the present invention is usually carried out at 30 to 1
It is carried out at a temperature of 00 ° C. and under atmospheric pressure or under pressure.

The copolymer obtained in the process of the present invention is usually in the form of relatively large particles, that is, having an average particle size of 1
Since it is obtained at a thickness of about 100 μm, the obtained copolymer can be easily obtained from the polymerization suspension by, for example, filtration.

The copolymer can be dried by a conventional method. In this case, the suspension obtained during the polymerization is used as it is, or a filter cake wet with a solvent after filtration is subjected to drying. For this purpose, conventional drying devices such as roll dryers, belt dryers, paddle dryers, spray dryers or fluidized bed dryers can be used.

With respect to the molecular weight of the obtained copolymer, a copolymer having a weight average molecular weight of 5 to 5,000,000, particularly 200 to 2,000,000 can be efficiently obtained.

[0026]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

The weight average molecular weight of the copolymer was determined by GPC.
Was measured using a 0.5% by weight DMF solution of the copolymer. GANTREZAN copolymer (methyl vinyl ether / maleic anhydride copolymer) manufactured by ISP was used as a molecular weight standard.

The evaluation of the presence or absence of aggregation was performed by visually observing the aggregation state during or at the end of the polymerization.

In all the examples, it was confirmed that no maleic anhydride was detected in the polymerization suspension after the completion of the reaction, and that the reaction was completed.

Example 1 The weight ratio of diisobutyl ketone / ethyl vinyl ether at the end of the reaction was 80/20, and the polymer concentration was 25%.
The reaction was performed as follows under the following settings. 25 g of maleic anhydride, 44.4 g of ethyl vinyl ether and 104.1 g of diisobutyl ketone were added to a 500-ml separable flask made of glass equipped with a separable flask stirrer, a reflux condenser and a nitrogen inlet tube. The mixture was heated to completely dissolve the maleic anhydride.

Next, an initiator solution consisting of 0.125 g of 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65] and 10 g of diisobutyl ketone was added all at once,
The reaction was carried out at 50 ° C. for 3.5 hours. No maleic anhydride was detected in the polymerization suspension after the completion of the reaction, and it was confirmed that the reaction was completed. Further, when the polymerization suspension was taken out of the separable flask, it could be easily taken out, and there was almost no adhesion of the polymer to the stirring blade of the stirring device and the wall of the separable flask. The obtained polymerization suspension was subjected to suction filtration, and was subjected to a vacuum drying at 85 to 95 ° C.
To obtain 43.98 g of a white powder. Table 1 shows the results.

Example 2 At the end of the reaction, the weight ratio of diisobutyl ketone / ethyl vinyl ether was 65/35, and the polymer concentration was 25%.
The reaction was carried out as follows under the following conditions. To a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 64.01 g of ethyl vinyl ether and 74.79 g of diisobutyl ketone were added, and stirred.
The mixture was heated to 0 ° C. to completely dissolve the maleic anhydride.

Next, an initiator solution consisting of 0.075 g of 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65] and 10 g of diisobutyl ketone was added all at once,
The reaction was performed at 50 ° C. for 2.5 hours. Thereafter, the same operation as in Example 1 was performed to obtain 46.02 g of a white powder. Table 1 shows the results.

Example 3 At the end of the reaction, the weight ratio of diisobutyl ketone / ethyl vinyl ether was 58/42, and the polymer concentration was 25%.
The reaction was carried out as follows under the following conditions. In a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 73.54 g of ethyl vinyl ether and 65.15 g of diisobutyl ketone were added, and stirred.
The mixture was heated to 0 ° C. to completely dissolve the maleic anhydride.

Next, an initiator solution consisting of 0.05 g of 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65] and 10 g of diisobutyl ketone was added all at once.
The reaction was performed at 0 ° C. for 4 hours. Thereafter, the same operation as in Example 1 was performed to obtain 43.96 g of a white powder. Table 1 shows the results.

Example 4 The weight ratio of diisobutyl ketone / ethyl vinyl ether at the end of the reaction was 50/50, and the polymer concentration was 25%.
The reaction was performed as follows under the following settings. In a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 83.57 g of ethyl vinyl ether and 55.19 g of diisobutyl ketone were added, and the mixture was stirred.
Heated to ℃ to completely dissolve maleic anhydride.

Next, an initiator solution consisting of 0.075 g of 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65] and 10 g of diisobutyl ketone was added all at once,
The reaction was performed at 50 ° C. for 2.5 hours. Thereafter, the same operation as in Example 1 was performed to obtain 45.75 g of a white powder. Table 1 shows the results.

Example 5 At the end of the reaction, the weight ratio of diisobutyl ketone / ethyl vinyl ether was 56/44, and the polymer concentration was 25%.
The reaction was carried out as follows under the following conditions. To a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 91.95 g of ethyl vinyl ether and 46.80 g of diisobutyl ketone were added, and stirred.
The mixture was heated to 0 ° C. to completely dissolve the maleic anhydride.

Next, an initiator solution consisting of 0.05 g of 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65] and 10 g of diisobutyl ketone was added all at once.
The reaction was performed at 0 ° C. for 4 hours. Thereafter, the same operation as in Example 1 was performed to obtain 42.84 g of a white powder. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 The reaction was carried out in the following manner without using diisobutyl ketone under the condition that the polymer concentration at the end of the reaction was 25%.
In a separable flask similar to that used in Example 1,
25 g of maleic anhydride and ethyl vinyl ether 18
2.45 g was added, and the mixture was heated to 30 ° C. with stirring to completely dissolve maleic anhydride.

Next, an initiator solution consisting of 0.05 g of 2,2'-azobis (2,4-dimethylvaleronitrile) [V-65] and 10 g of ethyl vinyl ether was added all at once,
The reaction was performed at 30 ° C. for 3 hours. Thereafter, the same procedure as in Example 1 was carried out to obtain 43.83 g of a white powder. No maleic anhydride was detected in the polymerization suspension after the completion of the reaction, and it was confirmed that the reaction was completed.

After the completion of the reaction, the produced copolymer was fixed on the wall surface and around the stirring rod and could not be easily removed. The weight average molecular weight of the obtained copolymer is 14
It was 50,000. Table 1 shows the results.

Comparative Example 2 The reaction was carried out as follows with the setting that the polymer concentration at the end of the reaction was 30%. In a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 36.73 g of ethyl vinyl ether and 7 g of diisobutyl ketone were placed.
8.15 g was added, and the mixture was heated to 30 ° C. with stirring to completely dissolve maleic anhydride.

Next, 6 ml of an initiator solution comprising 0.2 g of lauroyl peroxide and 20 g of diisobutyl ketone was added all at once, and the mixture was reacted at 60 ° C. for 5 hours. Thereafter, the same procedure as in Example 1 was carried out to obtain 43.2 g of a white powder. In this example, the weight ratio of diisobutyl ketone / ethyl vinyl ether at the end of the reaction was 82/18, and the polymer concentration was 30%. The weight average molecular weight of the obtained copolymer was 600,000. Table 1 shows the results.

Comparative Example 3 The reaction was carried out as follows with the setting that the polymer concentration at the end of the reaction was 25%. In a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 18.39 g of ethyl vinyl ether and 1 g of diisobutyl ketone were placed.
20.32 g was added, and the mixture was heated to 30 ° C. with stirring to completely dissolve maleic anhydride.

Next, 6 ml of an initiator solution comprising 0.2 g of lauroyl peroxide and 20 g of diisobutyl ketone was added all at once, and the mixture was reacted at 60 ° C. for 5 hours. Thereafter, the same procedure as in Example 1 was carried out to obtain 43.83 g of a white powder. In this example, the weight ratio of diisobutyl ketone / ethyl vinyl ether at the end of the reaction was 100/0, and the polymer concentration was 24%.

When unreacted maleic anhydride was quantified by gas chromatography, 2.2% of maleic anhydride was detected relative to the charged amount. The weight average molecular weight of the obtained copolymer was 200,000. Table 1 shows the results.

Comparative Example 4 The reaction was carried out as follows with the setting that the polymer concentration at the end of the reaction was 25%. In a separable flask similar to that used in Example 1, 25 g of maleic anhydride, 122.61 g of ethyl vinyl ether and 21.26 g of diisobutyl ketone were added, and heated to 30 ° C. with stirring to completely dissolve maleic anhydride. I let it.

Next, 6 ml of an initiator solution comprising 0.2 g of lauroyl peroxide and 20 g of diisobutyl ketone was added all at once, and the mixture was reacted at 60 ° C. for 5 hours. Thereafter, the same procedure as in Example 1 was carried out to obtain 43.98 g of a white powder. In this example, the weight ratio of diisobutyl ketone / ethyl vinyl ether at the end of the reaction was 20/80, and the polymer concentration was 25%.

After the completion of the reaction, the produced copolymer was fixed on the wall surface and around the stirring rod and could not be easily removed. The weight average molecular weight of the copolymer was 1.6 million. Table 1 shows the results.

[0051]

[Table 1]

[0052]

According to the present invention, in the production of an alkyl vinyl ether-maleic anhydride copolymer by precipitation polymerization, polymerization of the polymer at a high polymer concentration does not occur without agglomeration of the produced polymer or sticking to the wall of a reaction vessel or the like. The reaction can be carried out, and a high molecular weight alkyl vinyl ether-maleic anhydride copolymer can be efficiently produced.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 129/10 C09J 129/10 135/08 135/08 F term (Reference) 4J011 HA03 HA04 HB02 HB06 HB14 HB16 4J038 CE051 CG081 4J040 DD051 DG021 GA12 JA03 LA01 QA01 4J100 AE02P AK32Q CA04 FA00 JA03 JA05

Claims (2)

[Claims] 1. A solvent containing an aliphatic ketone comprising an alkyl vinyl ether represented by the following general formula (1): CH ₂ ＣＨCH—OR (R is an alkyl group having 2 to 4 carbon atoms) and maleic anhydride. When precipitation polymerization is carried out in water, the vinyl ether present in the solvent after the polymerization is expressed in terms of a weight ratio with respect to the aliphatic ketone: aliphatic ketone / vinyl ether = 80/2
A method for producing an alkyl vinyl ether-maleic anhydride copolymer, wherein the polymerization is carried out so as to be 0 to 40/60. 2. The process according to claim 1, wherein the alkyl vinyl ether is used in an amount exceeding 2 mol per 1 mol of the maleic anhydride at the time of the polymerization.