JPH0617416B2 - Method for producing α-methylstyrene copolymer - Google Patents

Description

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

[Conventional technology]

A polymer of α-methylstyrene is extremely easily decomposed to form a low molecular weight monomer or the like and easily scattered, so that it is expected to be used as a ceramic binder or an optical recording material. However, since α-methylstyrene has a low ceiling temperature, it is necessary to perform low-temperature anionic polymerization in order to obtain a high molecular weight substance, and a copolymer containing α-methylstyrene as a main component has hardly been known.

[Problems to be solved by the invention]

α-Methylstyrene homopolymer is an excellent polymer that easily decomposes into a monomer by heat, light, etc., but when it is used as a ceramic binder or optical recording material, it is alumina, silica, silicon carbide. , Silicon nitride, boron carbide, boron nitride, etc. are not well compatible with ceramic powders and are not suitable as binders, and even as an optical recording material, they are poorly compatible with the substrate after being coated and dried, and then peeling off. was there. On the other hand, it may be possible to copolymerize with a monomer having a polar group such as carboxylic acid, carboxylic acid amide, and carboxylic acid ester. It is not easy to copolymerize with the polar group-containing monomer, and development of a copolymer obtained by copolymerizing α-methylstyrene and the polar group-containing monomer has been desired.

[Means for solving problems]

The present inventors have earnestly studied a method for solving the above problems and arrived at the present invention.

That is, in the present invention, an unsaturated carboxylic acid and / or a derivative thereof is copolymerized with an unsaturated group-containing polymer of α-methylstyrene and divinylbenzene and / or diisopropenylbenzene in the presence of a radical polymerization initiator. At this time, the copolymer was dissolved in a solvent which is substantially immiscible with water, the radical polymerization initiator was soluble in the solvent and insoluble in water, and the copolymer was suspended in water. The method for producing an α-methylstyrene copolymer is characterized in that it is carried out in the state.

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

The copolymer of α-methylstyrene and divinylbenzene and / or diisopropenylbenzene can be produced by a radical polymerization method or an anionic polymerization method.
The proportion of divinylbenzene and / or isopropenylbenzene with respect to the sum of methylstyrene and divinylbenzene and / or diisopropenylbenzene is 2 to 30% by weight, but there are few problems during the production of the copolymer, and
It is also preferable for the next reaction.

In the above polymerization, a known radical polymerization initiator such as peroxide or azobisnitrile, and / or a known anionic polymerization initiator such as alkyllithium or sodium naphthalene can be used, and the polymerization conditions are Although there is no particular limitation, the method described in JP-A-59-207905 can be used.

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

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

These unsaturated carboxylic acids and / or derivatives thereof are used in an amount of 0.01 to 30% by weight in the resulting α-methylstyrene copolymer.

If it is less than 0.01% by weight, the compatibility with ceramics or the like is hardly improved, and if it exceeds 30% by weight, the characteristics of poly-α-methylstyrene are lost, which is not preferable.

Examples of the radical polymerization initiator used in the copolymerization of the polymer A with the unsaturated carboxylic acid and / or its derivative include aromatic hydrocarbons such as benzene, toluene, xylene and their derivatives, methylene chloride, ethylene dichloride, etc. A radical polymerization initiator that is soluble in a solvent that is insoluble in water and is insoluble in water, such as a halogenated hydrocarbon, but is insoluble in water, is suitable. Among the above-mentioned peroxides, benzoyl peroxide, 2,5 -Dimethyl-2,5-di-t-butylperoxyhexane, 2,5-dimethyl-2,5-di-
t-Butylperoxyhexyne-3, dicumylperoxide, t-butyl-cumylperoxide, etc. can be used.

The concentration of the polymer A in the solvent is 5 to 60% by weight, the ratio of the solvent and water is 10: 1 to 1:10, usually 3: 1 to 1: 3.
The ratio of the unsaturated carboxylic acid and / or its derivative to the polymer A is 0.05 to 30% by weight. The radical polymerization initiator is generally 0.001 to 1% by weight with respect to the solvent.

In the present invention, the reaction temperature is 0 to 100 ° C, preferably 30 to 100 ° C.

The reaction is preferably carried out in the presence of polyvinyl alcohol, sodium alginate, methyl cellulose, carboxymethyl cellulose and the like with vigorous stirring.

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

〔Example〕

 Hereinafter, the present invention will be further described with reference to examples.

The intrinsic viscosity of the polymer was measured with a toluene solution at 30 ° C.

Example 1 α-methylstyrene (10 vol%) in a toluene solvent,
Divinylbenzene (0.5vol%) with diethylene glycol dimethyl ether (0.2vol%) and butyllithium (15
wt% hexane solution, 0.15 vol%) was used to polymerize at −10 ° C. and then thrown into a large amount of methanol to obtain α-methylstyrene-divinylbenzene copolymer (intrinsic viscosity number 0.1).
9, divinylbenzene 5.2wt% included) 5g toluene 50
Dissolved in ml, polyvinyl alcohol (polymerization degree 1700)
100 ml of a solution prepared by dissolving 2 g in water 1 was added, and then 0.25 ml of N, N-dimethylacrylamide and 0.1% of acrylic acid.
Add 05 ml and benzoyl peroxide 0.3 g, and stir to 80
The reaction was carried out at ℃ for 4 hours. After completion of the reaction, the mixture was cooled to remove the aqueous layer, the toluene layer was washed twice with water, and the toluene layer was poured into a large amount of methanol. The intrinsic viscosity number of the obtained copolymer 1 was 0.20, and the contents of N, N-dimethylacrylamide and acrylic acid calculated by elemental analysis and infrared absorption spectrum were 1.8 wt% and 0.5 wt%, respectively.

Example 2 A polymer (copolymer 2) was obtained in the same manner as in Example 1 except that 0.05 ml of hydroxyethyl methacrylate was used instead of 0.05 ml of acrylic acid. The intrinsic viscosity number of the obtained copolymer 2 was 0.21, and the contents of N, N-dimethylacrylamide and hydroxyethyl ethacrylic acid ester were 1.9 wt% and 0.4 wt%, respectively.

Example 3 α-methylstyrene (20 vol%) in a toluene solvent,
Diisopropenylbenzene (1vol%) was added to -10 ℃ with butyllithium (10wt% hexane solution, 0.2vol%).
Polymerization was carried out for 0.5 hours at room temperature, and the mixture was poured into a large amount of methanol and separated in the same manner as in Example 1. The copolymer obtained has an intrinsic viscosity of 1.6.
3. The diisopropenylbenzene content was 5.7 wt%.

5 g of this copolymer was dissolved in 20 ml of benzene, 20 ml of an aqueous solution of 2 g of polyvinyl alcohol (degree of polymerization 1700) in 1 of water was added, and then 1 g of acrylamide and 0.2 g of dicumyl peroxide were added, followed by polymerization at 90 ° C. for 10 hours. did. The obtained reaction product was separated in the same manner as in Example 1 to obtain a copolymer 3 containing 2% by weight of acrylamide.

Using the copolymers 1 to 3 obtained in Examples 1 to 3 and the copolymers of α-methylstyrene and divinylbenzene or diisopropenylbenzene obtained in Examples 1 and 3, 10 g of each was added to 30 ml. 30 g of alumina (particle size: 2 μm) was added to the solution prepared by dissolving in toluene and kneaded, and the dispersibility was examined.

In the case of using the copolymers 1 to 3, a slurry in which alumina was uniformly dispersed was obtained, but when a polymer in which the unsaturated carboxylic acid and / or its derivative was not copolymerized was used, the alumina was uniform. Did not disperse in.

〔The invention's effect〕

By carrying out the method of the present invention, it is possible to obtain a copolymer of α-methylstyrene, which retains the decomposability of poly-α-methylstyrene itself, and is well compatible with ceramics and substrates. It is extremely valuable industrially.

Claims (1)

[Claims] 1. An unsaturated carboxylic acid and / or a derivative thereof is copolymerized with an unsaturated group-containing copolymer of α-methylstyrene and divinylbenzene and / or diisopropenylbenzene in the presence of a radical polymerization initiator. At this time, 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 suspended in water. The method for producing an α-methylstyrene copolymer, characterized in that the method is carried out in the above state.