JPS6227407A - 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 copolymerizing a specified unsaturated group-containing copolymer with an unsaturated carboxylic acid (derivative) in the presence of a radical polymerization initiator. CONSTITUTION:alpha-Methylstyrene is radical- or anion-copolymerized with 2-30wt% divinylbenzene and/or diisopropenylbenzene to obtain an unsaturated group-containing copolymer (A). Copolymer A is dissolved in a solvent such as toluene to form a solution of a concentration of 5-60wt%. At the same time an unsaturated carboxylic acid (derivative) (B) in an amount to provide a concentration of 0.05-20wt% is added to the solution, and further a radical polymerization initiator (C) (e.g., benzoyl peroxide) in an amount to provide a concentration of 0.001-1wt% is added thereto. The resulting solution is polymerized at -30-150 deg.C.

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 an α-methylstyrene copolymer having excellent decomposability and compatibility and suitable as a ceramic binder.

[Conventional technology]

Therefore, it is expected to be used in ceramic binders, optical recording materials, etc. However, α-methylstyrene has a low ceiling temperature (in order to obtain a high molecular weight product, low-temperature anionic polymerization must be carried out, so comonomers containing α-methylstyrene as the main component are hardly known. Ta.

[Problem that the invention seeks to solve]

α-Methylstyrene homopolymer is an excellent polymer that easily decomposes into monomers when exposed to heat, light, etc., but when it is used as a ceramic binder or optical recording material, alumina, silica, silicon It has poor compatibility with ceramic powders such as carbide, silicon nitride, boron carbide, and boron nitride, making it unsuitable as a binder, and also as an optical recording material.After being applied to a substrate and dried, it does not blend well with the substrate and peels off. There was such a problem. 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 since α-methylstyrene has the above-mentioned polymerization characteristics, other monomers may be used. Since it is difficult to copolymerize with a polar group-containing monomer, it has been desired to develop a copolymer in which α-methylstyrene and a polar group-containing monomer are copolymerized.

[Means for solving problems]

The present inventors have conducted extensive studies on methods for solving the above problems, and have arrived at the present invention.

That is, the present invention co-produces a wood-saturated phase group-containing copolymer of α-methylstyrene, divinylbenzene and/or diisopropenylbenzene, and an unsaturated carboxylic acid and/or a derivative thereof in the presence of a radical polymerization initiator. This is a method for producing a copolymer of α-methylstyrene, which is characterized by polymerization.

The unsaturated group-containing copolymer used in the present invention is a copolymer of α-methylstyrene and divinylbenzene and/or diisopropenylben. In this case, about 60% by weight of α-methylstyrene may be styrene or its derivatives. However, if it exceeds 303ii%, decomposability becomes poor, which is not preferable.

A copolymer of α-methylstyrene and divinylbenzene and/or hashiisopropenylbenzene can be produced by a radical polymerization method or an anionic polymerization method.
The ratio of divinylbenzene and/or impropenylbenzene to the total of methylstyrene and divinylbenzene and/or diisopropenylbenzene is 2 to 3% ON, since problems during production of the copolymer are small (and 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 is no limitation, the method described in Japanese Patent Application Laid-Open No. 59-207905 can also be used.

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.

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

These unsaturated carbons and/or derivatives thereof are present in the copolymer of α-methylstyrene obtained from 0,01 to 6
It is used so that it is 0% by weight. If it is less than 0.01% by weight, the compatibility with ceramics etc. will hardly be improved, and if it exceeds 30MJi%, the properties of poly-α-methylstyrene will be lost, which is not preferable.

The method of copolymerizing the above-mentioned polymer A with an unsaturated carboxylic acid and/or its derivative is not particularly limited as long as it is carried out in the presence of a radical polymerization initiator. It is carried out by adding a polymerization initiator (the ones mentioned above can be used) and an unsaturated phase carboxylic acid and/or its derivative, and maintaining the conditions (heating, light irradiation, etc.) under which the radical polymerization initiator acts. be exposed. At this time, the concentration to the polymer is usually 5
Preferably, the concentration of the unsaturated carboxylic acid and/or its derivative is maintained at 1.05 to 201% by weight, and the concentration of the radical polymerization initiator is maintained at 0, ooi to 1% by weight. The reaction temperature is suitably from -60°C to 150°C, preferably from 000°C to 100°C.

〔Example〕

Hereinafter, the present invention will be further explained with reference to Examples.

In addition, the intrinsic viscosity of one coalescence was measured using a 30° toluene solution.

Example 1 α-methylstyrene (10 vot%) in toluene medium
and divinylbenzea (0.5 vol%) in anionic polymerization initiator butyl lithium (15 wt% hexane solution, 0.5 wt% hexane solution,
An α-methylstyrene-divinylbenzene copolymer (intrinsic viscosity number 0.19, containing 5.2 wt% divinylbenzene) obtained by polymerizing at -10°C with 15 vol%) and then pouring into a large amount of methanol! M to toluene 90ml
N,N-dimethylacrylamide 0.5-,
After adding 0.1 part of acrylic acid and 0.251 part of benzoyl peroxide as a polymerization initiator and reacting at 80°C for 5 hours, the mixture was poured into a large amount of methanol. The intrinsic viscosity of the obtained polymer (copolymer 1) was 0.21, and N was calculated from elemental analysis and infrared absorption spectrum.

The contents of N-dimethylacrylamide and acrylic acid were 2.5 wt% and 3.8 wt%, respectively.

Example 2 A polymer (copolymer 2) was obtained in the same manner as in Example 1, except that hydroxyethyl methacrylate o, i rnt was used instead of acrylic. The intrinsic viscosity of the obtained copolymer was 0.20, and the contents of N,N-dimethylacrylamide and hydroxyethyl methacrylate were 2.4 wt% and 0.7 wt%, respectively.

Example 3 α-methylstyrene (20vat%) in toluene solvent
, diisopropenylbenzene (1 vot%) and butyl lithium (10 wt% hexane solution, 0.2 vot%) were polymerized at -10°C for 0.5 hours, and the mixture was poured into a large amount of methanol and separated in the same manner as in Example 1. The obtained copolymer had an intrinsic viscosity of 1.66 and a diisopropenylbenzene content of 5.
．． It was 7wt%.

This copolymer 102 was dissolved in 100 g of dimethylformamide, 0.5 F of acrylamide and 0.52 F of azobisisobutyronitrile were added, and the mixture was polymerized at 70° C. for 10 hours. According to elemental analysis, the obtained copolymer 3 contained 3 wt% of acrylamide, and its intrinsic viscosity was 1.72.

Using copolymers 1 to 3 obtained in Examples 1 to 5 above and copolymers of α-methylstyrene and dihinylhenzene or hashiisopropenylbenzene obtained in Examples 1 and 3, 101 of each was Alumina (particle size 2 μm) 30F was added to a solution dissolved in toluene and kneaded to examine dispersibility.

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, it is possible to obtain a copolymer of α-methylstyrene that maintains its own decomposability and is compatible with ceramics, substrates, etc. It is extremely valuable industrially.

Claims (1)

[Claims] 1. Characterized by copolymerizing an unsaturated group-containing copolymer of α-methylstyrene and divinylbenzene and/or diisopropenylbenzene with an unsaturated carboxylic acid and/or its derivative in the presence of a radical polymerization initiator. A method for producing a copolymer of α-methylstyrene.