SU410058A1 - - Google Patents

Description

one

This invention relates to the synthesis of polyurethanes.

A known method for producing polyurethanes by reacting a polyoxy compound, for example a polyester, a diisocyanate and a diamine coupling agent. However, the known method does not allow to obtain polyurethane elastamers with high hydrolytic and thermal resistance.

In order to obtain polyurethane elastomers with enhanced thermal and hydrolytic resistance, it has been proposed to use as a polyoxide compound a mixture of polyester and glycol having an average molecular weight of 800-1600.

The essence of the proposed method is that the di-eocyanate is reacted with a mixture of polyester with a molecular weight of 2000-2500 with low molecular weight glycol, the number average molecular weight of the mixture should be 800-1600, and an aromatic diamine with electronegative is used as a cross-linking agent. a substituent in the ortho position (for example, 3,3-dichloro-4,4-diaminodiphenylmethane, 3,3-dinitro-4,4-diaminodiphenylmethane, 3,3-dimethyl-4,4-diaminodiphenylmethane; 3,3difluoro-4, 4-diaminodiphenylmethane, etc.)

The polyesters used are the product of the reaction of dicarboxylic acids with glycols of the general formula HO (CH2) n OH, where n 2 is 10.

Ethylene glycol, 1,2 propylene glycol, diethylene glycol, 1,4-butanediol, 1,3-butanediol, triethylene glycol, hexanediol, and others can be used as low molecular weight glycol. According to the proposed method, various organic diisocyanates can be used, for example, 2,4-toluene diisocyanate and 4,4-diphenylmethane diisocyanate.

The polymers according to the specified method can be obtained both in two and in one stage. When preparing the polymer in two stages, a prepolymer based on isomeric-hydroxyl-containing compounds (a mixture of polyester and low molecular weight glycol with average molecular weight of 800-1600) and diisocyanate is initially prepared, and then the diamine is introduced. The following molar ratio of the starting components — hydroxyl-containing: diisocyanate: diamine — 1: 2: (0.2-2) is used.

The prepolymer is obtained by adding diisocyanate to a mixture of polyester with a low molecular weight diol at a temperature of 70-90 ° C in vacuum (2-5 mmHg) and vigorous stirring for 60-120 minutes. The prepolymer obtained is treated with the above diamines at 70 ° C and after 5 minutes of stirring, the finished polymer is poured into the mold. In order to carry out a one-step method of synthesis in the case of using diamines as cross-linking agents, catalysts such as triethylenediamine, tin dibutyldyl laurinate, tin octoate, iron acetylacetonate must be used. In this case, at the temperature of 70-80 ° C, the catalyst and the cross-linking agent — any of the above diamines — 1 In an amount of 0.2–2 moles relative to the amount of polyester added to the previously prepared mixture of polyester with low molecular weight glycol with a average molecular weight of 800–1600. hydroxyl-containing compounds The mixture is stirred under vacuum (residual pressure of 5 mm Hg) at the indicated temperature of 20 1 MIN. Then, at a temperature of 45-50 ° C, diisocyanate is added (a 2: 1 ratio of diisocyanate: hydroxyl-containing and, after stirring for 30 seconds, the liquid polymer is poured into a formula. A polyurethane elastomer can be obtained by changing the number average molecular weight of the polyester mixture with glycol with a desired hardness of from 65 to 98. With a decrease in the average molecular weight of the mixture and hydro, xyloxy-containing compounds, elastomers are obtained, which have greater hardness. polyurethane can be processed into products using modern technological methods - liquid-phase casting, casting under vacuum and centrifugal casting, and, if necessary, by pressing. Example 1. 100 g of polyethylene adipate, previously dried at 110 ° C for 1.5-2 hours in vacuum (2-5 mm Hg. Art.), Mol% by weight 1800, mixed at 80 ° C for 20 minutes with 4.7 g of 1,4-butanediol. A mixture of hydroxyl-containing compounds with a mean molecular weight of 1000 is obtained. 36.4 g of 2,4-toluene diisocyanate are added to the mixture; and a temperature of 90 ° C for 60 min in vacuo (2.5 mm Hg. Art.). At the temperature of 70 ° C, 21.3 g of 4,4-methylene bis (2-chloroaniline) are introduced into the prepolymer, stirred at this temperature for 5-10 1min, pour the polymer into molds and cure. Physico-mechanical properties of the obtained elastomer are shown in the table. Example 2. An elastomer is prepared according to the procedure described in Example 1 using a mixture of hydroxyl-containing compounds (500 g of polyethylene adipate with a mol. Weight of 2000 and 11.2 g of 1,4-butanediol) with a number average molecular weight of 1300, 136.5 g 2,4-toluene diisocyanate, 84 g 4,4-methylene bis- (2 chloroaniline). Physico-mechanical properties of the obtained elastomer are shown in the table. Example 3. An elastomer is obtained according to the method; described in example 1, using a mixture of .hydroxyl-containing compounds (250 g of polyethylene adipinate with a molecular weight of 1200 and 7.74 g of ethylene glycol) with a mean molecular weight of 1000, 89.4 g of 2,4-toluene diisonate, 455.4 g 4 , 4-methylene bis- (2 chloroaniline). Physico-mechanical properties of the obtained elastomer are shown in the table. Example 4. An elastomer is prepared according to the procedure described in example 1 using a mixture of hydroxyl-containing compounds (197 g of polyethylene adipate with a mol. Weight of 1800 and 3 g of ethylene glycol) with a mean molecular weight of 1300, 53.6 g of 2,4-toluene diisocyanate 32 9 g of 4,4-methylene bis- (2 chloroaniline). The physicomechanical properties of the resulting elastomer are shown in Table 1, Example 5. The elastomer is obtained according to the procedure described in Example 1 using a mixture of hydroxyl-containing compounds (100 g of polyethylene adipate with a molecular weight of 1800 and 5.8 g of gbbxanediol) with a number average molecular weight. 1000, 32.8 g of 2,4-toluene diisocyanate, 20.2 g of 4.4- | Methylene bis- (2-chloroaniline). Physico-mechanical properties of the obtained elastomer are shown in the table. Example 6. Get the elastomer according to the method described in example 3, using as a crosslinking agent 35.3 g of 4,4-methylene-bis- (2-fluoroaniline). Physico-mechanical properties of the obtained elastomer are shown in the table. Example 7. An elastomer is obtained according to the procedure described in example 1 using a mixture of hydroxyl-containing compounds (93.8 g of polyethylene adipate with a molar weight of 3000 and 6.2 g of 1,4-butanediol) with a number of molecules of 1000, 29 , 4 g of 2,4-toluene diisocyanate and 15 g of 4,4-methylene bis- (2 chloroaniline). Physico-mechanical properties of the obtained elastomer are shown in the table. Example 8. (One-step method). Offset 100 g pre-dried, as indicated in example 1, polyethylene adipate mol. weight. 1800 and 2 g of 1,4-butanediol are obtained a mixture of hydroxyl-containing compounds with average molecular weight of 1300. To the mixture obtained, at a temperature of 70 ° C, 0.02 g of triethylenediamine and 12.6 g of 4,4-methylene-bis- (2-Chloraniline), stirred at the same temperature for 15 minutes. 24.6 g of 2,4-toluene diisocyanate are introduced into the reaction mixture at a temperature of 50 ° C, stirred for 30 seconds and the finished product is poured into a mold. Next, the temperature control is carried out at 120 ° C for 20 hours. Physico-mechanical properties of the obtained elastomer are shown in the table. Example 9. According to the procedure of Example 1, an elastomer is obtained using a mixture of hydroxyl-containing compounds (150 tons of polyethylene adipate with a molecular weight of 3000 and 2.5 g of 1,4-butanediol) with a average molecular weight of 1800, 23.5 g of 2,4-toluene diisocyanate and 12 g of 4,4-methylene bis- (2-chloroaniline). Physicomechanical properties of the obtained elastomer are shown in the table. Example 10. According to the procedure of Example 1, an elastomer is obtained using a mixture of hydroxyl-containing compounds (200 g of polyethylene adipate with a mol. Weight of 200 and 8.5 g of 1,4-butanediol) with a number average molecular weight of 700, 93.2 g of 2,4-toluene diisocyanate and 57.2 g of 4,4-methylene bis- (2-chloroaniline). Physico-mechanical properties of the obtained elastomer are shown in the table. Example I. 100 g of polyethylene adipate mol. weight. 800, pre-dried, mixed at 80 ° C. for 60 minutes with 48.3 g of 2,4-toluene diisocyanate in vacuo. 22.9 g of 4,4-methylene bis- (2-chloroaniline) are added to the prepolymer thus prepared at 70 ° C, stirred for 10 minutes, the polymer is poured into a mold and cured at 120 ° C. The properties of the polymer obtained are listed in the table . Table

Elastomers of examples 1-8 have the time of hydrolysis (until complete destruction) in boiling water for 90-100 hours, polyurethane of example 9 - 1 hour, polyurethane of example 10 - 90 hours and polyurethane of example I - 30 hours.

From the data in the table, it can be seen that when using a mixture of hydroxyl-containing compounds with a number average molecular weight greater than 1600 (Example 9), crystallizable polyurethanes with low physicomechanical parameters are obtained.

Polyurethanes, obtained on the basis of a mixture of hydroxyl-containing compounds and their compounds with a number average molecular weight below 800 (Example 10), lose their elastic properties and are plastics (very high modulus, hardness, slight elongation, large residual elongation).

In the preparation of polyurethane elastomers on a polyester-based basis in the same molecular weight range (800-1600) without adding low molecular weight glycol (Example 11), it is also not possible to achieve an increase in thermal and hydrolytic stability. 7 Subject of the Invention A method of producing polyurethanes by reacting polyoxy compounds, diisocyanates and a cross-linking agent, characterized in that, in order to obtain polyurethane 8 elastomers with enhanced thermal and hydrolytic resistance, polyoxy compounds and glycol having average number of molecules are used as polyoxy compounds 800-1600.