DE1065611B - Process for the production of high molecular weight polymers and copolymers of α-methylstyrene and its derivatives substituted on the core - Google Patents

Description

GERMAN

It is known that it is very difficult to polymerize α-methylstyrene with radical formers. With ionic catalysts such as aluminum chloride, boron fluoride or titanium-4-chloride, α-methylstyrene can be polymerized to liquid to solid, brittle products. This polymerization is strongly dependent on the temperature. Solid polymers are only obtained at a polymerization ^{temperature of about −100 °} C. or below. With sulfuric acid or phosphoric acid, a-methylstyrene can be dimerized at higher temperatures. It is also known that α-methylstyrene can be polymerized with sodium to give high molecular weight products. However, this process can only be carried out very laboriously, since very long polymerization times are required, e.g. B. 100 to 150 hours and more. In addition, there are only slightly more polymerized than 50 ° / ₀ of the a-methyl styrene.

It has now been found that it is possible a-methyl styrene or its derivatives substituted on the nucleus derivatives advantageously at temperatures between -100 and + 6O ⁰ C with the aid of alkali metals polymerize to high molecular weight polymers if the polymerization is carried out in the presence of cyclic ethers and / or acetals undertakes.

In addition to α-methylstyrene, it can also be substituted on the core by the process according to the invention Derivatives, as long as they do not react with the groups substituted on the core with alkali metals, polymerized will. Such compounds are e.g. B. o-, m-, p-methylstyrene, 2,4-dimethyl-α-methylstyrene or others Dimethyl - α - methylstyrenes, ρ - isopropyl - α - methylstyrene, ρ -Vinyl - α - methylstyrene, ρ - isopropenyl - α - methylstyrene and the like.

The polymerization begins immediately after the components involved in the polymerization have been combined and then often proceeds so vigorously that the polymerization vessel has to be cooled. It is completed in 10 minutes to about 15 hours, depending on the degree of distribution of the alkali metal and the temperature used, and takes place at room temperature up to about 70% conversion. Below 0 ⁰ C, the conversion is about 90%, and is substantially complete at -20 ⁰ C.

The α-methylstyrene is expediently used immediately after it has been distilled. Are impurities included, e.g. B. auto-oxidation products, the polymerization also occurs, but more is needed Catalyst, and polymers with somewhat lower molecular weights are obtained. As alkali metals are particularly suitable for sodium, potassium or lithium. Mixtures or alloys of these metals with one another are useful.

Suitable cyclic ethers in the presence of which the polymerization is to be carried out are, for example, tetrahydrofuran or dioxane. Suitable methods of manufacture
of high molecular weight polymers

and copolymers

of a-methylstyrene and its on the core

substituted derivatives

ίο applicant:

Aniline & Soda Factory in Baden

Corporation,

Ludwigshafen / Rhine

Dr. Ernst-Günther Kastning

and Dr. Klaus Bronstert, Ludwigshafen / Rhine,

have been named as inventors

Acetals are for example acetaldehyde dimethyl acetal, Acetaldehyde diethylacetal or other acetals from aliphatic aldehydes with aliphatic alcohols, furthermore Benzaldehyde dimethyl acetal and the like mixtures of cyclic ethers with acetals are also useful. The cyclic ethers and the acetals not only serve to accelerate the polymerization process the polymerization, they also act as a diluent, so that the reaction mixture Can move and stir and thus good mixing of the components involved in the polymerization and also a good dissipation of the heat of polymerization achieved.

The polymerization can advantageously also be carried out in screws or kneaders. This is special useful when polymerizing continuously. When polymerizing in screws or kneaders takes place an intimate mixing of the polymerisation components also takes place when the polymerisation mixture is in the advanced stage of the polymerisation sation has already become very viscous and tough.

By moving the reaction medium, the heat of polymerization can be dissipated well, so that a Temperature constancy is guaranteed. Furthermore, a liquid reaction medium is advantageous for the work-up, because when pouring into an alcohol, such as. B. methanol, ethanol or propanol, or in water under brisk Stir the poly-α-methylstyrene immediately as white Powder is obtained in the pure state. The catalyst is washed out and remains in the process of being separated off

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of the polymer back in the washing liquid. The removal of the catalyst from a solid reaction medium causes greater difficulties.

The polymer can also be mixed with water or with steam or in a kneading machine in the presence be worked up by air. The end groups of the polymer occupied with sodium are oxidized, and polymeric alcoholates are obtained which can remain in the polymer and are used there as lubricants are effective.

A special peculiarity of the process is that after the polymerization has ended, a certain Amount of α-methylstyrene after adding more α-methylstyrene the polymerization continues, even after a longer 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. One can thereby determine the molecular weights set as desired. In practice, an upper limit is given by the fact that the polymerization becomes more sluggish with increasing dilution. For example, poly-a-methylstyrenes with intrinsic viscosities About 3 only formed after very long reaction times (up to 100 hours), while polymers with limiting viscosities up to 2 form in rapid reaction.

A polymerization that has already started can also be continued with other monomers instead of α-methylstyrene be 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 in succession or with α-methylstyrene continue the polymerization.

This results in copolymers in which the copolymer components are not statistically in the Polymer chain are distributed, but in which large sections of the polymer chain consist of one component. For example, mixed polymer chains were built up from the following components:

1. polymer chain

2. polymer chain

3. polymer chain

4. polymer chain

Poly-α-methylstyrene

Polystyrene

-I

Polystyrene

Poly-α-methylstyrene poly-α-methylstyrene

Polystyrene

Poly-a-methylstyrene polyisoprene

Polybutadiene

Poly-α-methylstyrene

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 the graft components as side chains contain.

However, if one or more of the copolymerization components are mixed with α-methylstyrene and polymerizes the mixture according to the present process, in this way mixed polymers are formed which contain the components in the polymer chains in a randomly distributed manner.

Oxygen and water, as well as alcohols, must be carefully excluded during the polymerization. Even The slightest traces of these substances are disturbing, especially if you are aiming for high molecular weights noticeable because each of these molecules breaks off a polymerization chain.

. The homo-polya-methylstyrenes obtained by this process have high mechanical resistance and temperature resistance. Soften them between 160 and 173 ° C. They have excellent dielectric properties and can be used to manufacture of temperature-resistant electrical insulating bodies are used.

From a technical point of view, graft polymers of poly-α-methylstyrene with styrene are of particular interest, since they are boil-proof and sterilizable. The softening point of such graft polymers is higher than that of the copolymers of the same composition; z. B. softens a copolymer of 22.5 ° / ₀ α-methylstyrene and 77.5% styrene at 108 ° C, while a graft polymer of the same composition only softens at 113 ° C.

The parts mentioned in the examples are parts by weight.

All k values (according to Fikentscher, Cellulosechemie, Vol. 13, p. 58 [1932]) are measured in 1% toluene solution. . . . .

Polystyrene example 1

In a stirred vessel, 100 parts are made under nitrogen freshly distilled a-methylstyrene, 50 parts of dried tetrahydrofuran and 0.5 part of sodium chips at a Stirred temperature of 25 ° C. After about 10 minutes the metallic sodium dissolves and the polymerization begins begins with the reaction mixture turning red. The heat of reaction is dissipated by external cooling. The polymerization is complete after a total of about 30 minutes. The very viscous reaction product is introduced into methanol with vigorous stirring, the poly-α-methylstyrene separating as a white powder. This is washed with methanol and dried in vacuo at 100 ° C. 77 parts of poly-a-methylstyrene are obtained, which has a k value of 46.5 and a softening point of 165 ° C. With the same approach, but in the absence of tetrahydrofuran, no polymerization takes place after 100 hours.

Example 2

150 parts are gradually added to 236 parts of α-methylstyrene and 1 part of sodium powder at 20 ° C. with stirring Given tetrahydrofuran. After the addition of the first 10 parts of tetrahydrofuran, the polymerization starts with a strong increase Heat generation, and the polymerization vessel is cooled from the outside. To the extent that the reaction mixture thickens, the remaining proportions of tetra- hydrofuran added so that the mixture can be stirred well until the end of the polymerization. The polymerization has ended after 45 minutes. The reaction mixture is washed with ethanol. Man receives 191 parts of poly-a-methylstyrene with a k value of 59.2 and a softening point of 169.5 ° C.

Example 3 300 parts of toluene are added. The temperature will be on

Maintained 30 ° C. After another hour, the

If you work as in Example 2, but instead of half of the reaction mixture worked up with methanol,

of 1 part of sodium powder 1.5 parts of potassium powder are obtained 174 parts of a graft polymer with a

applies, so you need to soften the reaction mixture to 5 ° C of 113.5 ° C, which is 22.5%

to be able to stir well at the end, only 110 parts of tetra-a-methylstyrene and 77.5% of styrene and one

hydrofuran. The polymerization has a k value of 57 ^{after 4 1} _{2 hours.}

completed. After working up as in Example 1, the other half of the reaction mixture is obtained with

158 parts of poly-ct-methylstyrene with a k value of 42.2 are added to a further 50 parts of a-methylstyrene and the mixture is heated at 20.degree

and a softening point of 162 ° C. further polymerized. After 10 hours it will be almost

. . solidified reaction mixture with methanol to one

^{Grind 1} P ¹ white powder. Remain after cleaning

200 parts of a-methylstyrene are back with 5 parts of tetra 198 parts of polymer with a k value of 61.5, hydrofuran and 0.3 parts of sodium turnings at 10 ° C

Rolled in a roller jar for 3 hours. During this time 15 is example 9

the sodium has gone into solution, and the reaction 100 parts of a-methylstyrene are mixed with 50 parts of acet

mixture becomes highly viscous. After a further 12 hours of aldehyde dimethyl acetal and 0.5 part of sodium powder

The contents of the container harden completely when they stand at 10 ° C. Stirred at 25 ° C. for 12 hours. The reac-

The reaction mixture is mixed with methanol to a powder then mixed in with vigorous stirring

grind, which then entered 20 500 parts of methanol for cleaning with methanol. The exiting

is boiled and washed. 174 parts of white powder are obtained and are filtered off with suction, washed with 1% strength aqueous salt

Poly-a-methylstyrene with a k value of 72.3 and an acid and then washed with water and then

Softening point of 171 ° C. dried. The k value of the poly-a-methylstyrene is

_. . , _ 48, the softening point 164.5 ° C.

Example 5 25 t> r.

100 parts of α-methylstyrene are mixed with 0.5 part of Na Example 10

trium chips and 50 parts of tetrahydrofuran at 25 ° C. 80 parts of p-isopropyl-a-methylstyrene are mixed with 30 parts

polymerized as in Example 1. 5 hours after completion, add tetrahydrofuran and 0.1 part sodium powder

In order to polymerize, 500 parts of α-methylstyrene are stirred at 15.degree. C. for 8 hours. After working up the reac-

admitted. After mixing, the polymerization mixture with methanol sets 53 parts powdery

tion again, and there is intensive cooling with poly-p-isopropyl-a-methylstyrene with a k value of 37.5.

Ice water to maintain the reaction temperature of. ^ ₁₁₁

25 ° C required. To stir the reaction mixture go to Example 11

350 parts of tetrahydro- In a kneader are 1,500 parts of α-methylstyrene

furan too. After working up as in Example 1, 35 and 50 parts of tetrahydrofuran are mixed with 1 part of sodium powder

422 parts of poly-α-methylstyrene with a k value of 62 are kneaded at 10.degree. The will be within 45 minutes

and a softening point of 170 ° C. Content has become highly viscous. Then 2 parts of butanol

. -if. kneaded in and thereby destroys the catalyst. At-

⁶¹³ P ^{1 e} closing the mixture in a vacuum for 30 minutes

50 parts of α-methylstyrene are heated in the presence of 40-190 ° C. Doing so will solvents and not

50 parts of tetrahydrofuran and 0.05 part of sodium-converted α-methylstyrene were removed. The melted one

chips polymerized at 0 ° C. If the polymerization is poly-a-methylstyrene then it is via a heated pipe

begins after about 15 minutes, another 250 parts are under 2 atm. Pressure removed from the kneader. It has

α-Methylstyrene gradually added, so that the k value of 60.5 and a softening point

Reaction mixture remains stirrable. After 2 hours 45 is from 161 ° C.

all a-methylstyrene entered, and after another example 12
Hour because of the high viscosity the mixture

can no longer be stirred. After a further 10 hours, 4,000 parts of freshly distilled α-methylstyrene become the reaction mixture, which has become very stiff, is mixed with 2,000 parts of tetrahydrofuran under nitrogen Grind to a white powder. 50 mixes are obtained. Add 2 parts of finely powdered Na-175 Share poly-a-methylstyrene with a k value of 78 trium. The reaction continues to turn red after about and a softening point of 173 ° C. 5 minutes and is finished after about 60 minutes.

. -17 External cooling increases the reaction temperature

Example 7 is _{kept at 1Q0 c, with} cooling and stirring

100 parts of a-methylstyrene are in the presence of 55 1,000 parts of freshly distilled styrene in the course of

100 parts of tetrahydrofuran and 0.05 part of sodium were added dropwise for 3 hours. 30 minutes after the last styrene

polymerized powder at -30 ° C. The polymerization continues, the reaction is carried out by adding 100 parts

About 20 minutes after the components have been brought together, methanol ends. The viscous reaction mixture will

noticeably and subsides after about 60 minutes. After then in a kneader with 10,000 parts of methanol

The reaction mixture is kneaded for a further 12 hours for 60 to 45 minutes. A white powder is obtained,

Methanol worked up. There are 96.5 parts of poly-a-methyl- which is washed neutral with water. From-

styrene with a k value of 83.5 and a softening yield is 2,410 parts. The graft polymer consists

point of 171 ° C. from 62% α-methylstyrene and 38% styrene. It softens

_π . . ₁₀ at 138 ° C and has a k value of 77.1.

Examples ₆

100 parts of α-methylstyrene are poly- Example 13 as in Example 1

merized. After the polymerization is complete, a mixture of 200 parts of α-methylstyrene and

Mixture diluted with 200 parts of toluene, and 200 parts of styrene, both freshly distilled, are added Period of 4 hours with stirring and strong external nitrogen, 500 parts of tetrahydrofuran and 3 parts of ultra-fine cooling becomes a mixture of 300 parts of styrene and 70 parts of powdered sodium. After the reaction started

a mixture of 750 parts of styrene, 750 parts of α-methylstyrene and 2,500 parts of tetrahydrofuran is added dropwise in the course of 2 hours. After a further hour, dry air (50 l / hour) is passed into the reaction mixture for 2 hours. During the entire duration of the reaction, the reaction temperature is kept at 12 ° C. by cooling. The mixture is finally worked up with methanol as in Example 12. 455 parts of a copolymer of 42% α-methylstyrene and 58% styrene with a softening point of 130 ° C. and a k value of 63.8 are obtained. The dielectric constant is 0.92 and the impact strength is 14.5 kg / cm ² .

Example 14

0.8 parts of finely powdered sodium are added to a mixture of 100 parts of styrene and 500 parts of tetrahydrofuran with vigorous stirring and intensive cooling at -20 ° C. The reaction vessel is flushed _{with N 2.} The reaction begins after a few minutes and the temperature rises to 10 ° C. 300 parts of α-methylstyrene are then added all at once, the mixture is mixed thoroughly and the temperature is maintained at 10 ° C. The reaction is complete after 45 minutes. A further 100 parts of styrene are then added in the course of 30 minutes.

1 hour after the last addition of styrene, the reaction is terminated by adding 20 parts of methanol. The mixture is kneaded with 1,500 parts of methanol until the polymer is in powder form. 436 parts of a block graft polymer are obtained which contain 54 ° / ₀ α-methylstyrene and 46 ° / ₀ styrene and have a k value of 68.4.

Example 15

100 parts of α-methylstyrene are as in Example 1 described, polymerized. When the polymerization is complete, it is added dropwise to the reaction mixture Stirring in the course of 30 minutes 15 parts of highly purified isoprene mixed with 100 parts of tetrahydrofuran while maintaining the reaction temperature by external cooling at 25 ° C. The mixture is then

ίο kneaded in 200 parts of ethyl alcohol to a white powder, which is sucked off and washed neutral with water. This gives 96.5 parts of a Blockmischpolymerisates consisting of 16 ° / ₀ 84 isoprene and ⁰ / _& α-methyl styrene. It softens at 142 ° C. and has an impact strength of 32 kg / cm ² and a k value of 59.7.

Claims (1)

Claim: Process for the preparation of high molecular weight polymers or copolymers of α-methylstyrene or its derivatives substituted on the core at temperatures between -100 and +6O ⁰ C with the aid of alkali metals, characterized in that in the presence of cyclic ethers and / or acetals with exclusion polymerized by oxygen, water and alcohols. Considered publications:
French Patent No. 802,707;
U.S. Patent No. 2,458,378;
German Auslegeschriften No. 1 010 274, 1 010 275. © 909 628/443 9. 59