JPS61115937A - Production of granular copolymer - Google Patents

Abstract

PURPOSE:To obtain easily a granular copolymer, by copolymerizing isobutylene with maleic anhydride in a solvent which can dissolve a formed copolymer, introducing the resulting reaction soln. into water, separating the resulting agglomerate and crushing it. CONSTITUTION:Isobutylene and maleic anhydride are copolymerized in the presence of a radical polymn. catalyst (e.g. benzoyl peroxide or azobisisobutyronitrile) in a solvent (e.g. acetonitrile or dimethylformamide) which can dissolve the resulting copolymer and has a solubility coefficient of 11 or above. The resulting reaction mixture is introduced into water, and the agglomerate of a copolymer precipitated in water is separated by filtration. The agglomerate is crushed in a mortar to obtain a granular isobytylene/maleic anhydride copolymer. The resulting copolymer can be used as a material for paints without pelletizing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a granular copolymer, and more particularly to a method for producing a copolymer that can be easily formed into a granular copolymer by a simple operation.

BACKGROUND ART Conventionally, there has been known a method of copolymerizing isobutylene and maleic anhydride to produce a copolymer thereof. This copolymer is used as a material for adhesives, paints, etc., and its production usually employs a solution polymerization method using a solvent that dissolves the resulting copolymer.

After the completion of the polymerization reaction, the solvent was distilled off to obtain a bulk copolymer, which was then ground by mechanical means into powder or granules.

However, the copolymer obtained by this conventional method is extremely hard and requires a great deal of force to crush, making it difficult to operate.

Therefore, as a result of intensive research into a method for obtaining a powder-like copolymer more easily, the present inventor discovered that a copolymer that can be easily pulverized can be obtained by an extremely simple operation of pouring it into water. , completed the present invention based on this knowledge.

That is, the present invention involves copolymerizing isobutylene and maleic anhydride using a solvent that dissolves the resulting copolymer, and then pouring the resulting reaction solution into water to obtain an aggregate. The present invention provides a method for producing a powdery copolymer, which comprises pulverizing a coagulant.

As the isobutylene used in the present invention, a butane/butylene mixed fraction obtained by thermal decomposition of petroleum or the like is usually suitable.

In the present invention, the proportions of isobutylene and maleic anhydride to be used are not particularly limited and may be appropriately determined in consideration of the physical properties of the intended copolymer. Usually, the amount is 0.5 to 1.5 mol, preferably about 1 mol, of maleic anhydride per 1 mol of isobutylene.

Copolymerization of isobutylene and maleic anhydride according to the present invention 1
The reaction proceeds by radical copolymerization.

Therefore, a radical catalyst is usually used. Various catalysts can be used, including organic peroxides such as benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, and dicumyl peroxide; azobisisobutyroyl peroxide; Examples include azo compounds such as nitriles; persulfates, and the like. The amount of catalyst used is 0°01 to 10% per 100 parts by weight of total monomers.
Parts by weight, preferably 0.05 to 5 parts by weight. The catalyst may be used as is or diluted.

Furthermore, the catalyst may be added in its entirety at the beginning of the polymerization, or may be added in portions during the polymerization.

Next, in the present invention, when performing a copolymerization reaction, a solvent that dissolves the copolymer to be produced is used as a solvent. Such a solvent preferably has a solubility coefficient of 11 or more, and specific examples thereof include acetonitrile, nitroethane 2 dimethylformamide, dimethyl sulfoxide, allyl alcohol, acetylmorpholine, and acetylpiperidine. There is no particular limit to the amount of solvent used, but
The amount is usually 50 parts by weight or more, preferably 100 to 500 parts by weight, based on 100 parts by weight of all monomers. When this solvent is used, a polymerization reaction solution in which the copolymer is dissolved in the solvent can be obtained.

In the method of the present invention, first a copolymerization reaction of the above monomers is carried out. Copolymerization reaction conditions include reaction temperature of 30 to 200°C, preferably 45 to 150°C, reaction pressure of normal pressure to 30 kg/
aITG, preferably normal pressure to 10 kg/dG, reaction time 0.5 to 20 hours, preferably 1 to 10 hours.

After producing an inbutylene-maleic anhydride copolymer under these conditions, the polymerization reaction solution is poured into water. There is no particular restriction on the charging method, and the polymerization reaction solution may be dropped into water little by little, or the polymerization reaction solution may be added all at once.

Although there are no restrictions on the amount of water, water temperature, etc. at this time, it is preferable that the water be in a non-stationary state. A non-static state can be achieved by stirring or other means. When the water is brought into a non-stationary state by stirring, there are no particular restrictions on the stirring conditions, and it may be carried out as appropriate using means such as stirring blades or pumps.

Next, the aggregates of the copolymer precipitated in the water are separated by an operation such as filtration. This aggregate contains an appropriate amount of solvent, is soft, and can be easily crushed in a mortar or the like. By pulverizing this aggregate by a simple operation using a mortar or the like, a powdery copolymer can be obtained. As the crushing equipment, a high-speed rotary crusher, a ball mill, a pneumatic crusher, a tank disintegrator, a media stirring mill, etc. can also be used.

The resulting powdery copolymer is relatively uniform, with an arbitrary particle size of 10 μm or more, although it varies depending on the pulverizing equipment used.

Therefore, the obtained isobutylene-maleic anhydride copolymer powder can be used as it is as a raw material for adhesives, paints, etc. without requiring any molding process such as pelletizing.

As described above, according to the method of the present invention, easily friable copolymer aggregates can be obtained by extremely simple operations, and by crushing the aggregates, powdery copolymers can be easily produced. .

In addition, although the present invention copolymerizes two components, isobutylene and maleic anhydride, in addition to these two components, a third component is also copolymerized.
It can also be applied to 48-, which produces a terpolymer using monomers such as methyl acrylate, vinyl acetate, and styrene as components.

Next, the present invention will be explained in detail with reference to examples.

Examples 1 to 3 Predetermined amounts of the solvent, catalyst, and maleic anhydride shown in Table 1 were placed in a 1j2 autoclave, and the autoclave was cooled and degassed.

Next, after adding a predetermined amount of isobutylene, the mixture was stirred at 40 Or, p, m under the conditions shown in Table 1 to carry out a copolymerization reaction.

After the copolymerization reaction was completed, the mixture was dropped into water at 20° C. and 10,100 O over 1 minute while stirring at 100 r, p, m.

Next, the aggregates precipitated in the water were filtered and dried, and ground in a mortar to obtain a powdery copolymer.

Difficulty in crushing aggregates, number average molecular weight of copolymers.

The density is shown in Table 1.

Comparative Examples 1 to 3 Copolymers f were produced in the same manner as in Example 1, except that the types of solvents were changed to those shown in Table 1, and aggregates were obtained by filtration.

This aggregate was filtered and dried to remove the solvent. This material was ground in a mortar to obtain a powdery granular copolymer. The difficulty in pulverizing this copolymer aggregate and its physical properties are shown in Table 1.

Comparative example 4 A copolymerization reaction was carried out in the same manner as in Example 1.

Then, the solvent was distilled off to obtain a dried copolymer. This material was ground in a mortar to obtain a powdery granular copolymer. Table 1 shows the difficulty of pulverization and physical properties of this copolymer.

Claims (3)

[Claims] (1) When copolymerizing isobutylene and maleic anhydride, copolymerize using a solvent that dissolves the resulting copolymer, then pour the resulting reaction solution into water to obtain an aggregate, and A method for producing a powdery copolymer, the method comprising: pulverizing a powdery copolymer. (2) The manufacturing method according to claim 1, wherein the solvent has a solubility coefficient of 11 or more. (3) The manufacturing method according to claim 1, wherein the solvent is acetonitrile, nitroethane or dimethylformamide.