JPS6227406A - Production of alpha-methylstyrene copolymer - Google Patents

Abstract

PURPOSE:To obtain the titled copolymer excellent in degradability and compatibility and good in affinity for ceramics, substrates, etc., by dissolving a specified copolymer in a water-immiscible solvent and copolymerizing an unsaturated carboxylic acid (derivative) with the copolymer in the presence of a radical polymerization initiator soluble in the solvent and insoluble in water. CONSTITUTION:alpha-Methylstyrene is copolymerized with 2-30wt% divinylbenzene and/or diisopropenylbenzene in the presence of a radical- or anion-polymerization initiator to obtain an unsaturated group-containing copolymer. This copolymer is dissolved in a solvent which is immiscible with water and dissolves said copolymer, such as benzene or methylene chloride, to form a solution of a concentration of 5-60wt%. 1-10pts.wt., per 10-1pts.wt. this solvent, water is added to this solution, and 0.05-30wt%, based on said copolymer, unsaturated carboxylic acid (derivative) [e.g., (meth)acrylic acid (ester)] is suspension- copolymerized at 0-100 deg.C in the presence of 0.001-1wt% (based on the solvent) radical polymerization initiator which is soluble in the solvent and insoluble in water.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a copolymer of α-methylstyrene. Specifically, the present invention relates to a method for producing a copolymer of α-methylstyrene, which has excellent decomposability and compatibility and is suitable as a ceramic binder.

[Conventional technology]

Polymers of α-methylstyrene are extremely easily decomposed into low-volume monomers, etc., and are easily scattered, so they are expected to be used in ceramic binders, optical recording materials, and the like. however.

α-methylstyrene has a low ceiling temperature, and in order to obtain a high molecular weight product, it is necessary to perform low-temperature anionic polymerization.
Almost no copolymers containing methylstyrene as a main component were known.

[Problem that the invention seeks to solve]

α-Methylstyrene homopolymer is an excellent polymer that easily decomposes into 1C monomers when exposed to heat, light, etc., but when it is used as a ceramic binder or optical recording material, alumina, silica, silicon carbide, etc. It is not compatible with ceramic powders such as silicon nitride, boron carbide, and boron nitride, making it unsuitable as a binder.

Even as an optical recording material, there have been problems such as poor compatibility with the substrate and peeling after it has been applied to the substrate and dried. To deal with this, copolymerization with a monomer having a polar group such as carboxylic acid, carboxylic acid amide, or carboxylic acid ester may be considered, but α-methylstyrene has the above-mentioned polymerization characteristics, so it is difficult to It is difficult to copolymerize α-methylstyrene with a polar group-containing monomer, and it has been desired to develop a copolymer obtained by copolymerizing α-methylstyrene with a polar group-containing monomer.

[Means for solving problems]

The present inventors have intensively studied methods for solving the above problems and have arrived at the present invention.

That is, 1 the present invention provides an unsaturated group-containing polymer of ct-methylstyrene and divinylhensen and/or hashiisopropenylbenzene with an unsaturated carboxylic acid and/or a derivative thereof in the presence of a radical polymerization initiator. During polymerization, the copolymer is dissolved in a solvent that is substantially immiscible with water, the radical polymerization initiator is soluble in the solvent and insoluble in water, and the copolymerization is soluble in water. This is a method for producing an α-methylstyrene copolymer, characterized in that it is carried out in a cloudy state.

The unsaturated group-containing copolymer used in the present invention is a copolymer of α-methylstyrene and divinylbenzene and/or diisopropenylben. At this time, about 30% by weight of α-methylstyrene may be styrene or its derivatives. However, if it exceeds 30% by weight, decomposability becomes poor, which is not preferable.

A copolymer of α-methylstyrene with divinylbenzene and/or diisopropenylbenzene can be produced by a radical polymerization method or an anionic polymerization method.
The ratio of divinylbenzene and/or isopropenylbenzene to the total of methylstyrene and divinylhensen and/or hashiisopropenylbenzene is 2 to 30% by weight, which causes fewer problems during the production of the copolymer ( ,Also.

Also preferred for the next reaction.

In the above polymerization, it is possible to use a known radical polymerization initiator such as peroxide or azobisnitrile, and/or a known anionic polymerization initiator such as alkyllithium or sodium naphthalene, depending on the polymerization conditions. Although there are no particular limitations, it is also possible to use the method described in Japanese Patent Application Laid-Open No. 59-207905.

The copolymer obtained by the above method is separated from unreacted monomers to obtain a vinyl group- and/or impropenyl group-containing copolymer (hereinafter abbreviated as polymer A). This is used in the reaction described below.

Examples of unsaturated carboxylic acids and/or derivatives thereof used in the present invention include acrylic acid, methacrylic acid, acrylamide, N,N-dimethylacrylamide, methacrylamide, N,N-dimethylmethacrylamide, and acrylic acid ester.

Examples include methacrylic acid esters.

These unsaturated carboxylic acids and/or their derivatives have a content of 0.01 to 30 in the resulting α-methylstyrene copolymer.
% by weight.

If it is less than 0.01% by weight, there will be little improvement in compatibility with ceramics, etc., and if it exceeds 30% by weight, poly-α
- The properties of methylstyrene are lost, which is undesirable.

The radical polymerization initiators used in the copolymerization of the above-mentioned polymer A with unsaturated carboxylic acids and/or derivatives thereof include aromatic hydrocarbons and derivatives thereof such as benzene, Toluev, Ki'/L/7, methylene chloride, A radical polymerization initiator that dissolves the above polymer A, such as a halogenated hydrocarbon such as ethylene dichloride, is soluble in a water-immiscible solvent, and is insoluble in water, is suitable, and among the above-mentioned peroxides, benzoyl Peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-235-
Di-t-butylperoxyhexine-3, dicumyl peroxide, t-butyl-cumyl peroxide, etc. can be used.

The concentration of Polymer A in the solvent is 5 to 60% by weight.

The ratio of solvent to water is 10:1 to 1:10. Usually 3:1~
The ratio of the unsaturated carboxylic acid and/or its derivative to the polymer A is 0.05 to 30% by weight. In addition, the radical polymerization initiator has a ratio of 0.001 to 1 to the solvent.
Weight percentages are common.

In the present invention, one reaction temperature is 10 to 100°C, preferably 30 to 100'C.

The reaction is preferably carried out under strong stirring in the presence of polyvinyl alcohol, sodium alginate, methylcellulose, carboxymethylcellulose, and the like.

In the present invention, after the above reaction, the aqueous layer is separated and removed, the solvent layer is washed with water if necessary, and if necessary, a large amount of alcohol can be added to the solvent layer to separate the polymer.

〔Example〕

The present invention will be further explained below with reference to Examples.

Note that the intrinsic viscosity of the 1M combination was measured at 30°C using a toluene solution.

Example 1 α-methylstyrene (10vol!%) in toluene solvent
), divinylbenzene (0.5vo/%), ethylene glycol dimethyl ether (0.2voJ%) and butyl lithium (15wt% hexane solution, 0.15vo/%).
%) at -10°C and then poured into a large amount of methanol.
5f (containing 2wt%) was dissolved in 50% of toluene, 100% of a solution of polyvinyl alcohol (degree of polymerization 1700) 2P dissolved in 11% of water was added, and then 0.25% of N,N-dimethylacrylamide was added. Z, 0.05-acrylic acid, and 0.3 g of benzoyl peroxide were added, and the mixture was reacted at 80° C. for 4 hours with stirring. After the reaction was completed, the mixture was cooled and the aqueous layer was removed, the toluene layer was washed twice with water, and the toluene layer was poured into a large amount of methanol. The intrinsic viscosity of the obtained copolymer 1 is 0.2
0, and the contents of N, N-dimethylacrylamide and acrylic acid calculated from single element analysis and infrared absorption spectrum were each 1.8 wt%.

It was 0.5 wt%.

Example 2 A polymer (copolymer 2) was obtained in the same manner as in Example 1, except that 0.05% of hydroxyethyl methacrylate was used in place of 0.05% of acrylic acid.

The intrinsic viscosity of the obtained copolymer 2 was 0.21.

The content of N,N-dimethylacrylamide and hydroxyethyl methacrylate is 1 and 9 wt%, respectively.
, 0.4 wt%.

Example 3 α-methylstyrene (20voI!%) in toluene solvent
), diisopropenylbenzene (1vo1%) woptyllium (10wt% hexane solution, 0.2voI!%
) for 0.5 hour at -10°C, and the same as in Example 1 was poured into a large amount of methanol and separated. The obtained copolymer had an intrinsic viscosity of 1.63. The fc containing diisopropenylbenzene was 5.7% by weight.

This copolymer 5y was dissolved in benzene 2o-, an aqueous solution of polyvinyl alcohol (degree of polymerization 1700) 2F dissolved in water 11-1 was added thereto, then acrylamide 1f and dicumyl peroxide 0.2f were added, and the mixture was heated at 90°C. Polymerization was carried out for 10 hours. The obtained reaction product was separated in the same manner as in Example 1 to obtain Copolymer 3 containing 2 wt % of acrylamide.

Copolymers 1 to 3 obtained in Examples 1 to 3 above Using the copolymers of α-methylstyrene and divinylbenzene or diisopropenylbenzene obtained in Examples 1 and 3, each loy was 30 - 30 f of alumina (particle size: 2 μm, a) was added to a @ solution dissolved in toluene and kneaded, and the dispersibility was examined.

When copolymers 1 to 3 were used, alumina was uniformly dispersed in the slurry, but when a polymer that was not copolymerized with unsaturated carboxylic acid and/or its derivative was used, alumina was uniformly dispersed. was not dispersed.

〔Effect of the invention〕

By carrying out the method of the present invention, poly-α-methylstyrene itself maintains its 04 degradability.

Furthermore, it is possible to obtain an α-methylstyrene copolymer that is compatible with ceramics, substrates, etc., and is extremely valuable industrially.

Claims (1)

[Claims] 1. An unsaturated carboxylic acid and/or an unsaturated group-containing copolymer of α-methylstyrene and divinylbenzene and/or diisopropenylbenzene in the presence of a radical polymerization initiator.
or a derivative thereof, when copolymerizing the copolymer, the copolymer is dissolved in a solvent that is substantially immiscible with water, and the radical polymerization initiator is soluble in the solvent and insoluble in water, and further, A method for producing an α-methylstyrene copolymer, characterized in that the copolymerization is carried out in a suspended state in water.