DE1066742B - Process for the production of high molecular weight polymers and copolymers of α-methylstyrene and derivatives of α-methylstyrene substituted on the core - Google Patents

Description

INTERNAT. KL. C 08 f

FEDERAL REPUBLIC OF GERMANY

PATENT OFFICE

EXPLAINING PUBLICATION 1066 742

B48871IVb / 39c

REGISTRATION DATE: MAY 10, 1958

NOTICE
LOGIN
AND ISSUE OF THE
EDITORIAL: OCTOBER 8, 1959

It is known that a-methylstyrene with radical-forming Catalysts can only polymerize with great difficulty. With ionic catalysts, e.g. B. with Aluminum chloride, boron fluoride or titanium-4-chloride, α-methylstyrene turns into liquid to solid, brittle Products polymerized. This polymerization is strongly dependent on the temperature. Fixed products is only obtained at polymerization temperatures of around - 100 ° C or below. With sulfuric acid or Phosphoric acid can be dimerized α-methylstyrene. It is also known that α-Alethylstyrene with sodium can be polymerized, resulting in higher molecular weight polymers. However, this procedure is technically quite cumbersome, as you have very long polymerization times required, e.g. 115 to 150 hours and more. The sales are also only about . 50 to 60%, and the polymerization is only between 0 and 30 ° C can be carried out. The subject of a separate, older proposal is a procedure in which a-methylstyrene on its own or with other monomers with sodium in the presence of acetals or can be polymerized by cyclic ethers. In this way, rapid polymerization is obtained high molecular weight and technically valuable polymers and copolymers of α-methylstyrene.

It has now been found that a-methylstyrene or its derivatives substituted on the core, such as o-, p-, m-methyl-a-methylstyrene, o-, p-, m-isopropyl-a-methylstyrene, 2,4-dimethyl-a-methylstyrene, p-Butyl-α-methylstyrene and the like, between -100 and + 60 ° C advantageously produce high-dielectric polymers can when polymerized in the presence of an alkali hydride and an ether.

The polymerization begins soon after the components have been combined and proceeds quite vigorously. To dissipate the heat of polymerization, it is useful to cool the polymerization vessel. The polymerization is completed in 30 minutes to about 15 hours, depending on the degree of division of the alkali metal hydride, and proceeds at room temperature up to about 70% conversion. Below 0 ° C, the conversion is about 90%, and is substantially complete at -2O ⁰ C.

The α-methylstyrene or its derivatives are expediently used immediately after they have distilled are. If it contains impurities, e.g. B. auto-oxidation products, the polymerization occurs also one, but you need more catalyst and get slightly lower molecular weights.

Particularly suitable alkali metal hydrides are those of sodium or potassium, but also those of lithium. Mixtures can also be used. Likewise, complexes of alkali hydrides and hydrides of the II. Or III. Main group of the periodic table, such as B. Na (AlH ₄ ), suitable.

Method of manufacture

high molecular weight polymers

and copolymers

of a-methylstyrene

and derivatives substituted on the core
of a-methylstyrene

Applicant:

Aniline & Soda Factory in Baden

Corporation,
Ludwigshafen / Rhine

Dr. Ernsf-Günther Kastning and Dv. Klaus Bronster,

Ludwigshafen / Rhine,
. have been named as inventors

Of the ethers, in addition to dialkyl ethers, z. B. diethyl ether, diisopropyl ether, especially cyclic Ethers, such as tetrahydrofuran or dioxane, for the catalytic acceleration of the polymerization in Question.

It is advisable to use the ethers in a highly purified condition. At the same time the ethers serve as Diluents and ensure that the reaction medium can be moved and stirred. as additional diluents can also in- '

difference hydrocarbons, e.g. For example, pentane, hexane, octane, benzene, toluene and the like can be used. The heat of polymerization can be dissipated well by constant movement of the reaction medium, see above that a constant temperature is guaranteed. the

Polymerization can be carried out batchwise or continuously. Especially with continuous Polymerization processes have proven themselves kneaders or screw machines. Through the constant Movement and thorough mixing of the polymer

s; - <tion approach here are a rapid polymerization and ensures good heat dissipation.

A liquid reaction medium is used for work-up advantageous, because when pouring into

an alcohol, e.g. B. in methanol, ethanol or propanol or in water, while stirring vigorously, the poly-a-methylstyrene immediately as a white powder in pure state. The catalyst is washed out and remains when the poly-

merisates back in the washing liquid. The removal of the catalyst from a solid reaction medium presents considerably greater difficulties. However, the catalyst can be used in a solid reaction medium by air or by action of water vapor, e.g. B. when rolling, destroy and thereby cause discoloration of the polymer.

A special peculiarity of the process consists in the fact that, after the polymerization has ended, a be ίο correct amount of α-methylstyrene or its derivatives after adding again a-methylstyrene or its Derivatives continue the polymerization even after a long interruption (up to several days) can be. This increases the molecular weight of the polymer originally present; h., that newly added monomers polymerize onto the preformed polymer. You can already do one commenced polymerization to continue with other monomers instead of α-methylstyrene, e.g. B. with Styrene and nucleus-alkylated styrenes, also with dienes, e.g. B. butadiene and isoprene, or with vinyl carbazole. You can also use several of these monomers one after the other or again with α-methylstyrene continue the polymerization. This results in mixed polymers in which the mixed polymer components are not statistically distributed in the polymer chain, but in which large sections of the Polymer chain consist of one component.

The copolymers produced in this way are straight-chain graft polymers in contrast to graft polymers, the z. B. are made by grafting an irradiated polymer and die_ graft components included as side chains.

However, if one or more of the mixed polymerization components are mixed with α-methylstyrene or its derivatives and polymerizes the mixture according to the present process, they usually form Mixed polymers that contain the components in the polymer chains in a randomly distributed manner. Even Mixtures of different α-methylstyrene derivatives with one another or with α-methylstyrene can be copolymerized.

The straight-chain grafting of a further component onto poly-α-methylstyrene makes the polymer thermally very stable, e.g. B. up to about 260 ° C. Pure poly-α-methylstyrene, on the other hand, suffers This temperature already shows a noticeable depolymerization.

Oxygen and water, as well as alcohols, must be carefully excluded during the polymerization. Traces of these substances are also disturbing, especially if you are aiming for high molecular weights noticeable because every molecule of these substances breaks off a polymerisation chain. .

The poly-a-methylstyrenes obtained by the process according to the invention have high mechanical properties Resistance and temperature resistance. They soften between ToO and 173 ° C, have excellent dielectric properties and can be used to produce temperature-resistant electrical insulating bodies are used. Graft polymers of polyamethylstyrene are technically particularly valuable s with styrene, which can be processed into boil-proof and sterilizable products. The softening point of such graft copolymers is somewhat higher than that of the copolymers same composition.

The parts mentioned in the examples are parts by weight. All k values (according to Fikentscher, Celluloscchemie, Vol. 13, p. 58 [1932] are measured in 10% toluene solution.

example 1

With the exclusion of oxygen and moisture, 100 parts of pure a-methyl styrene and 40 parts of dried tetrahydrofuran with 5 parts of a 2O ^D / o suspension of sodium hydride in paraffin oil are mixed. This reaction mixture is stirred at 25 ° C. After about 15 minutes, the polymerization begins and the reaction mixture changes color. After a further 60 minutes, the conversion is about 29%. After 10 hours a conversion of 69.5% is reached and the reaction mixture is introduced into methanol with vigorous stirring, polyamethylstyrene separating out as a fibrous, white powder. It is washed with methanol and dried at 100 ° C. in vacuo.

The k value of poly-a-methylstyrene is 68.5, and the softening point is 167 ° C.

In the same approach, none is found in the absence of tetrahydrofuran even after 150 hours Polymerization takes place.

Example 2

500 parts of α-methylstyrene are stirred with 100 parts of tetrahydrofuran and 3 parts of finely powdered sodium hydride. When the polymerization begins, 400 parts of toluene are added as the reaction mixture thickens so that the contents of the vessel remain easily stirrable. The temperature is kept at 5 ° C. by external cooling. After a total of 20 hours, the reaction mixture is poured into 4000 parts of ethanol with vigorous stirring. The white, fibrous powder which precipitates is filtered off with suction, boiled again with ethanol and then ^{dried at 100 °} C. in a vacuum. 452 parts of poly-α-methylstyrene with a k value of 86.7 and a softening point of 172 ° C. are obtained.

Example 3 "

50 parts of α-methylstyrene are mixed with 50 parts of tetrahydrofuran and 5 parts of a 20% suspension of sodium hydride in paraffin oil at - 30 ° C. After 28 hours there is an orange viscous reaction mixture formed, which is mixed with 200 parts of methanol at - 30 ° C. That Polymer initially separates out like a rubber and gradually disintegrates into a white powder. To cleaning results in 48.8 parts of poly-α-methylstyrene with a k value of 54 and a softening point of 166.5 ° C.

Example 4

50 parts of α-methylstyrene are mixed with 25 parts of diisopropyl ether and 0.5 parts of finely powdered sodium hydride added and stirred at 20 ° C. After 16 hours the contents of the vessel become so highly viscous that the stirring must be interrupted. After a total of 24 hours, the reaction mixture is with Grind methanol to a powder. After cleaning, 36 parts of poly-a-methylstyrene are added a k value of 66.4 and a softening point of 168 ° C.

Example 5

500 parts of α-methylstyrene are polymerized as in Example 2]. The polymerization takes place after about 20 hours completed. 125 parts of styrene,

mixed with 125 parts of toluene, added to the reaction mixture. After another 4 hours this will be Reaction mixture worked up with methanol and purified. There are 524 parts of a linear graft polymer from 77% ct-methylstyrene and 23% styrene 5 with a k value of 62 and a softening point of 133 ° C.

Patent claims:

1. Process for the production of high molecular weight polymers of ct-methylstyrene and am Nuclear substituted derivatives of a-methylstyrene, characterized in that the polymerization at temperatures between -100 and

+ 60 ° C in the presence of an alkali metal hydride and an ether.

2. The method according to claim!, Characterized in that ct-methylstyrene or its derivatives is copolymerized with other copolymerizable monomeric compounds.

3. The method according to claim 1, characterized in that one first ct-methylstyrene or polymerizes its derivatives and then polymerizes with another polymerizable Monomers continues.

Considered publications:
German Auslegeschriften No. 1 010 274, 1 010275.

© 909 637/431 9.

Claims (3)

mixed with 125 parts of toluene, added to the reaction mixture. After a further 4 hours, the reaction mixture is worked up with methanol and purified. 524 parts of a linear graft polymer composed of 77% α-methylstyrene and 23% styrene 5 with a k value of 62 and a softening point of 133 ° C. are obtained. Patent claims: 1. Process for the preparation of high molecular weight polymers of α-methylstyrene and am Nuclear substituted derivatives of a-methylstyrene, characterized in that the polymerization at temperatures between -100 and + 60 ° C in the presence of an alkali metal hydride and carry out an ether. 2. The method according to claim 1, characterized in that a-methylstyrene or its derivatives is copolymerized with other copolymerizable monomeric compounds. 3. The method according to claim 1, characterized in that one first or a-methylstyrene polymerizes its derivatives and then polymerizes with another polymerizable Monomers continues. Considered publications:
German Auslegeschriften No. 1 010 274, 1 010275. © 909 637/431 9.