DE1720178C3 - Process for the production of thermoset diene polymers - Google Patents

Description

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The German patent 16 45 503 relates to a process for the production of heat-cured diene polymers by reacting a polyfunctionally substituted one produced by anionic polymerization Polydiene prepolymer with a polyfunctional organic chain extender, Which is able to react with the functional groups of the diene prepolymer, at room temperature or moderately increased temperature and hardening <les chain-extended product with the help of heat and a hardener. This process is characterized in that one is polyfunctionally substituted Diene prepolymer one whose polymer structure has predominantly 1,2-configuration and the free radicals used as hardeners adding the supplying peroxide initiator to the diene prepolymer before the chain extension reaction, with the chain extension reaction below the activation temperature of the Peroxydini-Üators works and the hardening after the chain extension reaction by increasing the temperature above the activation temperature of the peroxide initiator performs.

Those used to make the resins according to the method of German Patent 1645503 Polydiene prepolymers have vinyl groups on alternating carbon atoms of the carbon structure, which make up at least 80% of the olefinic unsaturation. The molecular weight should preferably about 500-3000. The preferred polydiene is 1,2-polybetadiene, however, is 3,4-polyisoprene is also suitable. Difunctional polydiene prepolymers, which are characterized by a terminal Substitution are preferred. It is true that a dihydroxy-substituted prepolymer is used generally preferred for its ready reactivity, but it can also be dicarboxy-substituted compound or a diene prepolymer with other chemically functional ones Groups that preferably sit in terminal position can be used in a satisfactory manner.

The selection of a suitable organic chain extender depends on the functional group on the diene prepolymer. Are the functional ones Groups on the prepolymer hydroxyl group should then be the chain extenders consist of diisocyanates, diacid halides, diacids or diesters. Are the functional groups on the prepolymer carboxyl group, then the chain lengthening agents should be made from diepoxides, Diamines, diols and diaziridines exist. If the prepolymers contain reactive amino groups, then the organic chain extenders can be made from diisocyanates, diacid halides and diesters can be selected. The organic chain extenders are preferably difunctional, however, they can also contain more than 2 functional groups.

The products obtained according to the method of German patent 16 45 503 are rigid products. It has now been found that by incorporating a certain plasticizer into the Products manufactured in accordance with German Patent 16 45 503 are rigid, semi-rigid or flexible as desired Can manufacture plastics.

Thus, according to the present invention, a modification of the method of the German Patent 16 45 503 proposed, which is characterized in that one in the implementation of the Diene prepolymer and the chain extender an alkene is also used as an internal plasticizer.

During the final cure, the vinyl group occurs of the plasticizer in the crosslinking chain between the terminal positions of adjacent ones condensed cycloaliphatic chains, being rigid, semi-rigid or flexible thermosetting plastics can be obtained. Examples of plasticizers used according to the invention are:

3-ethyl-pentane (l)

2-methyl-hexene-(l)

3-methyl-hexene-(l)

4-methyl-hexene-(l)

5-methyl-hexene-(l)

3-methyl-pentene- (l)

Dodecene (l)

Butene- (l)

2,3-dimethyl-butene (1)

3,3-dimethyl-butene (l)

2-ethyl-butene (l)

2-ethyl-3-methyl-butene (l)

2-methyl-butene (l)

3-methyl-butene (l)

Decen- (l)

Ethylene

1,1-diphenylethylene

Heptene (l)

Witch- (l)

Pentene (l)

2,3-dimethyl-pentene- (l)

2,4-dimethylpentene- (1)
3,3-dimethyl-pentene- (l)
. 2-ethyl-pentene- (l)
3-ethyl-pentene- (l)
2-methyl-pentene- (l)
3-methyl-pentene- (l)
4-methyl-pentene- (l)
Propene

2-methyl-propene (1)
Tetradecen- (l)
Octene (l)

The peroxide initiators are used to cyclize the vinyl groups of the polydiene and to use them neighboring chains. The peroxide initiator is added to the starting mixture together with the polyvene prepolymer, the plasticizer and the organic chain extender introduced, whereupon it is molecularly dispersed in the elastomeric polymer. After exposure to heat in the The final stage decomposes the peroxide initiator and supplies free radicals, which are a compound of vinyl groups allow with the formation of a condensed cycloaliphatic chain.

In the manufacture of these resins, the polyfunctional one becomes organic chain extenders in an approximately stoichiometric amount based on the Polydiene prepolymer, mixed in.

The internal plasticizer should be in an amount between 10 and 30 percent by weight, based on the prepolymer, while the peroxide is generally used in an amount between 0.5 and 10 percent by weight, based on the prepolymer, and preferably between 2 and 6 percent by weight is used.

Of course, larger and smaller amounts of peroxide can be used, the optimum being Amount of the particular peroxide initiator used, the polydiene prepolymer used and depends on the chain extender selected for the reaction.

After the ingredients have been mixed, the polymeric liquid is expediently in a vacuum degassed to remove trapped air and volatile contaminants. At room temperature or moderately elevated temperatures, a chain extension reaction takes place, with a elastomeric intermediate product is produced, which is characterized in that the free radicals supplying Peroxide initiator is molecularly distributed in it. The chain extension reaction can decrease the reaction temperature or time by means of catalytically active agents which are familiar to the person skilled in the art, be shortened, provided that these agents are not involved in the subsequent cyclization or crosslinking intervention. While the polymer is in this elastomeric state, it can be more simple Wise handled and processed. If a finished product is to be produced, then that will be rubber-like intermediate product heated to 66 to 204 ° C, cyclization and crosslinking taking place and a translucent plastic is obtained that is rigid, semi-rigid or flexible and impact-resistant is. Rapid heating of the starting materials to an elevated temperature can result in that the two reactions take place simultaneously. This is preferably avoided as it is gradual Hardening is preferred.

The following examples illustrate the invention: Example 1

20 parts of 1,2-polybutadicndiol with an average Molecular weight of 2000 and 2 parts of 1-octene are placed in a glass jar and thoroughly mixed together. Then 2 parts of toluene diisocyanate are added to the vessel and stirred, whereupon the addition of 0.4 parts of di-tert-butyl peroxide follows. The solution is stirred for so long until it becomes homogeneous. The solution is in a vacuum chamber at an applied vacuum of degassed approximately 1 mm Hg for approximately 5 minutes. After the degassing period is over, the material will poured into a mold and cured under the following curing conditions: 1. 15 days at 90 ° C in Air, 2. 10 days at 115 ° C in air and 3. 9 days at 170 ° C in a vacuum. The hardened resins are clear, translucent, and hard, and have a yellow color

ao color. The resins prepared in the above-described manner have the following physical properties Characteristics:

Hardness: 22 to 27 barcol units

specific heat: 0.352
* ⁵ beginning
Decomposition temperature: 466 ° C.

Example 2

7 parts of 1,2-polybutadiene diol with an average molecular weight of 2000 and 0.05 Parts of a polyurethane formation catalyst consisting of triethylenediamine are placed in a glass vessel given, whereupon the ingredients are gently warmed and stirred until the triethylenediamine has gone into solution. The jar and its contents are cooled to room temperature, whereupon the following amounts of material added and in the specified Order to be mixed:

1. 3 parts of 1-octene

2. 0.2 parts of di-tert-butyl peroxide

3. 0.7 parts of toluene diisocyanate.

The degassing of the material is carried out in the manner described in Example 1, whereupon the Material is poured into a mold and cured under the following curing conditions: 1. 3 days at 24 ° C in air, 2. 2 days at 90 ° C in air, 3. October

Days at 115 ° C in air and 4. 10 days at 170 ° C in vacuo. The hardened resins are clear, translucent, yellow and flexible and have a Barcol hardness of 0 to 3.

Example 3

18 parts 1,2-polybutadiene diol with an average molecular weight of 2000, 0.05 part Triethylenediamine, 2 parts of 1-octene, 0.4 parts of di-tert-butyl peroxide and 1.8 parts of toluene diisocyanate

formulated and degassed according to the manner described in Example 1. The material is then made into molds poured and cured under the curing conditions given below: 1. 2 days at 90 ° C in air, 2. 1 day at 115 ° C. in air and 3. 1.5 h at 170 ° C. in air. After removal from the molds these materials are in the form of 0.79 mm thick foils. The hardened resins are clear, translucent and yellow and have a hardness

between 15 and 20 barcol units. The plastic sheets are in case they are directly from room temperature immersed in liquid nitrogen, to a considerable extent against thermal shock resistant.

The advantages of the resins obtained in this way are obvious to the person skilled in the art. Manufactured according to the invention Resins are made from viscous polymeric materials, unlike others polymeric materials, curing is interrupted indefinitely at an intermediate stage can be. In the intermediate stage, there is an elastomeric material that is simply cut up, pierced, shaped or subjected to practically all mechanical processing measures can. After the finished article has been shaped, heat is applied, whereupon the object transforms into a rigid, semi-rigid, or pliable resinous material.

The resins can be mixed and mixed in a central factory to form the elastomeric intermediate product are implemented and then packed and sent to

ο be sent to the place of use. It lies It is obvious that such manufacturing methods allow the production of resin products with a previously enable unattainable uniformity.

Claims (1)

Claim: Process for the production of heat-cured diene polymers by reacting a through polyfunctionally substituted polydiene prepolymer produced with anionic polymerization a polyfunctional organic chain extender, which with the functional Groups of the diene prepolymer are able to react at room temperature or at a moderately elevated level Temperature and hardening of the extended chain product with the help of heat and a Hardener, the polyfunctionally substituted diene prepolymer being one whose Po- »5 lymerstruktur has predominantly 1,2-configuration, and the free one used as hardener Peroxide initiator providing free radicals even before the chain extension reaction to form the diene prepolymer is added, with the chain lengthening reaction below the activation temperature of the peroxide initiator works and the hardening after the chain extension reaction by increasing the temperature above the activation temperature of the peroxide initiator »5 carries out, according to Patent 16 45 503, characterized in that one in the implementation of the diene prepolymer and the chain extender an alkene as an internal plasticizer used.