DE945479C - Process for the production of foams from high molecular weight polyurethanes - Google Patents

Description

ISSUED JULY 12, 1956

F 12917 IVb / 39b

Polyurethanes

According to an older proposal, polyisocyanates, which are in Vinyl compounds are dissolved, act on branched polyesters, which are mainly hydroxyl and to a lesser extent have carboxyl end groups: In this reaction, those in the presence is carried out by polymerization accelerators and small amounts of water The following reactions take place: The polyisocyanate dissolved in the vinyl compound reacts with the predominantly existing hydroxyl groups of the poly ester linked via urethane groups, while those present to a lesser extent Carboxyl groups with polyisocyanates with elimination of small amounts of carbon dioxide with linkage react via carbonamide groups. The amount of carbon dioxide is achieved by using of water, which also reacts with isocyanates with elimination of carbon dioxide, increased. These Reactions go hand in hand with the polymerization process between the unsaturated Polyester and the vinyl component takes place.

The sum of these processes leads to a cross-linked foam, the formation of which is due to the carbonic acid produced during the reaction, which acts as a blowing agent. . Experience has shown that the amounts of polyisocyanate required in this reaction are very high, since only some of the polyisocyanates are used for the formation of carbonic acid, with at best two isocyanate groups reacting with one molecule of water to form ι moles of CO ₂ . The much larger part of the polyisocyanates which react with the hydroxyl groups of the polyester is lost for the fuel effect.

According to the invention, solutions or mixtures of unsaturated, wholly or predominantly, are brought Carboxyl end groups, branched or linear polyesters on the one hand and polymerizable Vinyl or allyl compounds, on the other hand, in the presence of polymerization accelerators with polyisocyanates for reaction. The use of predominantly or entirely of carboxyl end groups existing polyesters has the consequence that the reaction of each end group of the polyester with the Polyisocyanate is associated with the formation of carbonic acid. A link is made at the same time of the polyester chains via carbonamide groups. The result is that there is no longer any isocyanate for reactions is consumed that do not serve to deliver propellant. This increases the amount of polyisocyanate which is required to achieve a certain driving effect, compared to the above Procedure significantly reduced.

The production of such unsaturated ones consisting predominantly or entirely of carboxyl groups Polyester takes place according to processes known per se. One possibility is e.g. B. in the fact that one Esterification of saturated dicarboxylic acids with a larger excess of polyalcohols makes and polyesters containing hydroxyl groups formed in this way are unsaturated in the second phase Carboxylic anhydrides, such as maleic anhydride, with ring opening and formation of a free carboxyl group added up.

Of course, the saturated ones obtainable by the customary esterification methods can also be used and / or polyesters containing unsaturated hydroxyl groups to a lesser extent in Mixture with the carboxyl polyesters claimed here is also used as foam starting materials will.

Since the solutions of polyesters containing carboxyl groups in vinyl or allyl compounds are a have low viscosity, it is advantageous to add high molecular weight, unsaturated compounds, which cause a substantial increase in viscosity. By such additives it is achieved that uniform pore formation is achieved during the foaming process.

The foam process takes place in such a way that the carboxyl polyesters, which can also be found in a mixture with hydroxyl polyesters to a minor extent, after the addition of vinyl compounds and polyisocyanates as well as a few percent of polymerization accelerators and such activators that are capable of the conversion of Let isocyanates with carboxyl groups proceed more quickly, brought to temperatures between ο and 100 °. Peroxides or other radical formers such as azodiisobutyronitrile are particularly suitable as polymerization accelerators, and tertiary amines, phosphines or heavy metal salts as activators for the isocyanate-polyester reaction. Of vinyl compounds, styrene is of particular importance, and allyl compounds such as diallyl esters of dicarboxylic acids may also be mentioned.

Example i

1425 parts of oxyethylated trimethylolpropane of OH number of 800, 758.5 parts of phthalic anhydride and 73 parts of adipic acid and 6 parts of N-Dioxäthylaminodiphenyl are gradually heated up to 200 ⁰ with stirring. The distillation of the water split off begins at about 150 ^° . If the Übergangstemperatur- of passing over water to 8o ° liked it slowly sets vacuum and heated to 215 ^0th After 1 hour, a vacuum of 14 mm should be reached and the heating will continue for about 5 hours at 215 °. The polyester then has an acid number of 1.5 and an OH number of 230. A total of 165 parts of water are transferred during the esterification.

Allowing the temperature of the polyester on ioo ° and then fall to 854 parts of maleic anhydride, allows to 125 ⁰ rise and stirred for a further 1 hour. After cooling to 100 °, 1.5 parts of hydroquinone, 2.5 parts of a 10% strength copper oleate / styrene solution and 1200 parts of styrene are added.

8 parts of bis-N-diethylaminoethyl ester are stirred under 200 parts of this mixture. 5 parts of benzene peroxide and 50 parts of a high molecular weight polyester well. Now you bring 36 parts Toluylene diisocyanate in this solution and distributes it very well. Soon the heat will begin Foam development. The. Polymerization only starts more vigorously after the blowing process has ended Heat generation. A foam with particular heat and water resistance is obtained.

The stirred high molecular weight polyester was prepared as follows: 400 parts of an adipic acid glycol polyester of the OH number 56 are with 40 parts of maleic acid-bis-diethylene glycol ester and 48 parts of tolylene diisocyanate heated to 130 ° for 30 minutes. After the extension has taken place poured out in thin layers.

Example 2

200 parts of the carboxyl polyester in styrene (prepared according to Example 1) and 100 parts of a branched one Hydroxyl polyester with the OH number 200, produced by esterification of 2.5 moles of adipic acid, 0.5 mol of phthalic anhydride and 4 mol of a triol are mixed with 9 parts of bis-N-diethylaminoethyl adipate and 6 parts of benzoyl peroxide. Then stir 70 parts of toluene diiso-

cyanate under. Foam development and polymerisation begin immediately. You get a stiff Low specific weight foam.

For example I 3

1500 oxethylated trimethylolpropane with an OH number of 800, 445 parts of phthalic anhydride, 440 Parts of adipic acid and 30 parts of N-dioxäthylaminodiphenyl are, as described in Example 1, to a polyester with an acid number of 2 and an OH number of 220 condensed out. After cooling to 100 ° 860 parts of maleic anhydride are added on and allowed to rise to 125 °. After 1 hour it is cooled back to 100 ° and gives 1.5 parts of hydroquinone and 2.5 parts of a 10% copper oleate-styrene solution to. When the hydroquinone has dissolved, add 1,300 parts of styrene and stir well by.

8 parts of adipic acid-bis-N-diethylaminoethyl ester, 6 parts, are stirred into 200 parts of this mixture Benzoyl peroxide and 50 parts of the high molecular weight unsaturated polyester described in Example 1 a. When everything is dissolved, 38 parts of toluene diisocyanate are poured in a thin stream. Immediately Schaun development begins and then polymerization begins. The foam is rigid and has a very low specific weight.

Example 4

200 parts of the carboxyl polyester-styrene solution from Example 3 and 100 parts of a hydroxyl polyester of the acid number 2.5 and OH number 200, the one by thermal esterification of 2.5 mol Adipic acid, 0.5 mol of phthalic anhydride and 4 mol of hexanetriol are obtained with 6 parts Bis-N-diethylaminoethyl adipate, 6 parts of benzoyl peroxide and 70 parts of tolylene diisocyanate mixed. After a short time, carbon dioxide is split off and the mixture is blown up.

After completion of the foam and polymerisation process, the result is a more rigid, specifically lighter one Foam body with good mechanical properties.

Example 5

Claims (3)

Claims ·. 1. Process for the production of foams from high molecular weight polyurethanes, thereby characterized in that one contains unsaturated, wholly or predominantly carboxyl end groups, branched or linear polyesters and polymerizable vinyl or allyl compounds "gi.ii in the presence of polymerization inhibitors wrestles to react with polyisocyanates. 2. The method according to claim 1, characterized in that that the reaction with the use of saturated polyesters containing carboxyl end groups or of saturated or unsaturated, hydroxyl and carboxyl group-containing polyesters carried out will. 3. The method according to claim 1 and 2, characterized in that polyesters are used for the reaction, built into the tertiary bases are. According to the information in Example 4, 200 parts of the carboxyl-polyester-styrene mixture are used of Example 3 with 50 parts of the hydroxyl polyester mentioned in Example 4 and 5 parts of bis-N-diethylaminoethyl adipate and 6 parts of benzoyl peroxide mixed. 51 parts of toluene diisocyanate are then added with thorough stirring Contains parts of the high molecular weight unsaturated polyester described in Example 1, too. Of the The foaming process begins immediately with intense heat development. After the end of the polymerization is demolded. A rigid foam with a very low specific weight is obtained. G 609 555 7.56