JPS6227409A - 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 copolymer with an unsaturated carboxylic acid (derivative) in the presence of a radical polymerization initiator in unreacted alpha-methylstyrene. CONSTITUTION:1pt.wt. copolymer in a state dissolved in 1-10pts.wt. unreacted alpha-methylstyrene, obtained by radical-polymerizing or anion-polymerizing 98-70wt% alpha-methylstyrene with 2-30wt% divinylbenzene by using alpha- methylstyrene itself as a medium, is diluted, if necessary, with a solvent which can dissolve the obtained copolymer, such as an aromatic hydrocarbon. To this diluted solution an unsaturated carboxylic acid (derivative), e.g., (meth) acrylic acid (ester), and, if necessary, a radical polymerization initiator (e.g., benzoyl peroxide) are added, and the obtained solution is copolymerized at 0-150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing an α-methylstyrene copolymer. 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 for applications such as ceramic binders and optical recording materials.

However, α-methylstyrene has a low ceiling temperature;
In order to obtain a high molecular weight product, it is necessary to carry out anionic polymerization at a low temperature, and copolymers containing α-methylstyrene as a main component have hardly been known.

[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, and silicone carbon are used. It has poor compatibility with ceramic powders such as nitride, silicon nitride, poron carbide, and boron nitride, making it unsuitable as a binder, and also as a recording material. There was 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. 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 conducted extensive studies on methods for solving the above problems, and have arrived at the present invention.

That is, the present invention involves copolymerizing α-methylstyrene and divinylbenzene using α-methylstyrene itself as a medium, and then copolymerizing unsaturated carbon dioxide in the presence of a radical polymerization initiator in the presence of unreacted α-methylstyrene. A method for producing an α-methylstyrene copolymer, which comprises polymerizing an acid and/or a derivative thereof.

In the present invention, α-methylstyrene and divinylbenzene are first formed into a valve type. At this time, 3 of α-methylstyrene
About 0% by weight can be replaced by styrene or its derivatives. If the substitute amount exceeds 30% by weight, degradability will be poor, which is not preferable. A copolymer of α-methylstyrene and divinylbenzene can be produced by a radical polymerization method or an anionic polymerization method, and the ratio of divinylbenzene to the total of α-methylstyrene and divinylbenzene is 2 to 60% by weight. This is preferred because it causes fewer problems during the production of the copolymer and is also preferred for subsequent reactions.

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. There are no particular restrictions.

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 subjected to the next reaction in a state dissolved in unreacted α-methylstyrene. Here, the ratio of copolymer to unreacted α-methylstyrene is 1
It is common to set it as /1 - 1/1o. When carrying out the next reaction, it is also possible to additionally dilute the solvent in which the above copolymer is dissolved, and examples of such solvents include aromatic hydrocarbons, halogenated hydrocarbons, dimethylformamide, and the like.

An unsaturated carboxylic acid and/or a derivative thereof and, if necessary, a radical polymerization initiator are added to the copolymer solution to carry out a polymerization reaction.

Examples of unsaturated carboxylic acids and/or derivatives thereof used here include acrylic acid, methacrylic acid, acrylamide, N,N-dimethylacrylamide, methacrylamide, N,N-dimethylmethacrylamide, acrylic ester, and methacrylic acid. Acid esters are preferably used.

These unsaturated carboxylic acids and/or derivatives thereof are 001-3c in the resulting α-methylstyrene copolymer.
It is used with great weight.

If the amount is less than 0.001% by weight, there will be little improvement in compatibility with ceramics, etc., and if it exceeds 30% by weight, poly-α-
This is not preferred because the properties of methylstyrene are lost.

There are no particular restrictions on the radical polymerization initiator used in the latter reaction, and the radical polymerization initiator used in the first reaction is the one used in the first reaction. , is available. For example, peroxides include benzoyl peroxide, 2゜5-dimethyl-2,5
-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-t-butylperoxyhexane-3,
Preferred examples include dicumyl peroxide, t-butylcumyl peroxide, and azobisnitrile such as azobisisobutyronitrile.

Radical polymerization initiators, including those left over from the previous reaction, are α
-o, ooi~ for the sum of methylstyrene and solvent
It is common that the weight is 1. Here, the reaction temperature is 0 to 150°C, preferably 30 to 100°C.

In the present invention, unreacted monomers and the like are removed from the coelectric material thus obtained by distillation, steam distillation, methanol precipitation, etc. to obtain a copolymer of α-methylstyrene.

〔Example〕

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

Example 1 Using α-methylstyrene itself as a solvent, divinylbenzene 5 voZ%, diethylene glycol dimethyl ether 0.2 vol%, butyl lithium (15 wt.
% hexa solution) was added, and polymerization was carried out at 15° C. for 60 minutes with stirring. A small amount of methanol was added to stop the reaction, and one part was sampled to measure the copolymer concentration, divinylpene content, and intrinsic viscosity in a toluene solution at 30°C, which were 35 wt% and 6.1 wt%, respectively.
It was 0.85.

Then 50 ml of a solution of the above copolymer KN, 0.25 ml of N-dimethylacrylamide and 0.25 ml of acrylic acid were added.
Add 05++yJ and further add 0.3y benzoyl peroxide.
was added, and the mixture was reacted at 80° C. for 4 hours with stirring. After the reaction was completed, the copolymer was separated by pouring it into a large amount of methanol. When the obtained copolymer 1 was analyzed, the intrinsic viscosity number was 086, and elemental analysis and infrared absorption spectrum showed that N, N-dimethylacrylamide and acrylic acid were each 1.1.
wt%, and 0.4 wt%.

Example 2 Polymer 2 was obtained in the same manner as in Example 1, except that 0.05 ml of acrylic acid was replaced with hydroxyethyl methacrylate 005. The intrinsic viscosity of the obtained copolymer 2 was 086, and the contents of N,N-dimethylacrylamide and hydroxyethyl methacrylate were t3wt% and 0.5wt%, respectively.

Example 6 α-methylstyrene was dissolved in divinylbenzene (3v
ot%) and 02 wt% of benzoyl peroxide were added, and the mixture was reacted at 70°C for 10 hours.

After the reaction was completed, the reaction was stopped by cooling, and one part was sampled to measure the copolymer concentration, divinylbenzene content, and intrinsic viscosity, which were 12 wt% and 7.0 wt%, respectively.
, 0.95. This polymer solution 150m/,
Door 1/en 100++t/! , acrylamide5.
Add Or and dicumyl peroxide 037 and heat to 80°C.
It reacted for 5 hours. After the reaction was cooled and washed with water, the solution was poured into a large amount of methanol to obtain a copolymer filter.

The resulting copolymer 6 had an intrinsic viscosity of 099, and an acrylamide content calculated from elemental analysis of more than 5.1 w.

Using copolymers 1 to 6 obtained in Examples 1 to 3 above and copolymers of α-methylstyrene and divinylbenzene in Examples 1 and 6, 102 of each was dissolved in 30 g of toluene,
30ii' of alumina (particle size: 2 μm) was added thereto and kneaded, and the dispersibility was examined.

Copolymers 1 to 6 had good dispersibility and became uniform slurries, but copolymers in which unsaturated carboxylic acids and/or derivatives thereof were not copolymerized were not uniformly dispersed.

〔Effect of the invention〕

By carrying out the method of the present invention, the decomposability of poly-α-methylstyrene itself can be maintained, and ceramic and
It becomes possible to obtain a copolymer of α-methylstyrene that is compatible with substrates, etc., and is extremely valuable industrially.

Claims (1)

[Claims] α-methylstyrene and divinylbenzene are copolymerized using α-methylstyrene itself as a medium, and then unreacted α
- A method for producing an α-methylstyrene copolymer, which comprises copolymerizing an unsaturated carboxylic acid and/or a derivative thereof in the presence of methylstyrene and a radical polymerization initiator.