CS225259B1 - The production of the low-fusing modified copolyamide - Google Patents

Description

The invention relates to a process for the production of a low-melting modified copolyamide comprising structural units derived from caprolactam, dodecanoactam and hexamethylenediemonium adipate.

It is known that the copolymerization of the caprolactam, dodecanolactam, hexamethylenediammonium adiapate system is difficult because dodecanolactam requires long-term heating to a high temperature of at least 290 ° C to achieve a high degree of conversion. At these temperatures, however, the entire copolymerization system, in particular hexamethylenediammonium adipate, is decomposed, and irregular structural units are incorporated into the polymer. Therefore, ways have been sought to remedy these shortcomings. For example, according to USP 3,536,780, this problem is solved by using polydodecanolactam instead of monomeric dodecanolactam in copolymerization, and the copolymerization can thus be carried out at a lower temperature. The disadvantage, however, is that the copolymerization time is too long, at least 15 hours.

This drawback can be remedied by copolymerizing a mixture of said monomers or their polymers according to the process of the invention, characterized in that the copolymerization is carried out at a pressure of 0.5 to 2 MPa at 260-280 ° C for 2- 8 hours in the presence of phosphoric acid and higher aliphatic carboxylic acids of at least 10 carbon atoms.

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The advantages of the process for the production of the low-swellable copolyamides according to the invention are the possibility of significantly reducing the reaction time, which leads to a sufficiently effective suppression of decomposition reactions under the increased pressure. With longer reaction times and lower temperatures, energy and other manufacturing costs are saved, which is economically advantageous. Further advantages of the process of the present invention reside in the increased hydrophobicity of the copolyamides formed by the action of higher aliphatic carboxylic acids in that the terminal amino groups of the copolymer are not only blocked, but are bound by a long aliphatic chain of hydrophobic properties. This is particularly important when using the copolyamides prepared according to the invention as a hot melt adhesive, for example in the textile industry. Thus, these advantages of the process for producing the copolyamides of the present invention represent technical progress.

Example 1

287 moles of caprolactam, 198 moles of dodecanolactam, 217 moles of hexamethylenediammonium adipate, 1 kg of staarin, 1 mol% of phosphoric acid were charged into the autoclave. The reaction mixture was heated at 270 ° C and 1.6 MPa for 4 hours with stirring. After this time, the pressure was reduced to atmospheric, the temperature to 260 ° C and stirring continued for 30 minutes. After this time, the melt was transported by a gear pump through a nozzle with the resulting melt flow led through a trough of water where it solidified to a string from which granules of 4x2 mm were prepared in a granulator. After drying, the granules were milled to a grain size of 80-200. The melting point of the product was in the range of 114-118 ° C and had a viscosity of 16,000 mPa.s at 150 ° C. When used in the textile industry as a hot-melt adhesive, it exhibited high adhesion, which was quite sufficient even after 5-fold cleaning in perchlorethylene and trichlorethylene and was also resistant to detergents.

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Example 2

The autoclave was charged with the same amount of monomeric components and phosphoric acid as in Example 1. Instead of stearin, 1 kg of a mixture of aliphatic acids formed after lanolin hydrysis and 0.2 kg of stearylamine was used. The mixture was heated with stirring at 280 ° C under a pressure of 1.5-1.8 MPa for 2 hours. After this time, the pressure was reduced to atmospheric, the temperature to 260 ° C and the melt stirred at this temperature for 60 minutes. The melting point of the product is 115-118 ° C and the viscosity at 150 ° C is about 18 000 mPa.s.

Example 3

A mixture of 200 g of polycaprolactam, 400 g of polydodecanolactam and 400 g of nylon 6.6 was charged in an autoclave, 20 g of 85% phosphoric acid and 20 g of lauric acid were added. Heat at 260 ° C under 1.8 MPa with stirring for 7 hours. After this time, the pressure in the autoclave was reduced to atmospheric and stirring was continued for 30 minutes. The melting point of the resulting copolymer was about 135 ° C.

Claims (4)

OBJECT OF OUT / CLIMB A process for the production of a low-melting modified copolyamide comprising structural units derived from caprolactam, dodecenolactam and hexsmethylenediammonium adipate, characterized in that the mixture of caprolactam, dodecenolactam and hexamethylenediammonium adipate or polymers thereof is heated to a temperature of 260-280 ° C at a pressure of 0.5-280 ° C. the presence of phosphoric acid and aliphatic carboxylic acids containing more than 10 carbon atoms or mixtures thereof with aliphatic amines with more than 10 carbon atoms for 2-8 hours · 2. A process according to claim 1, characterized in that phosphoric acid is added in an amount of 0.3-3 mol% and carboxylic acid in an amount of 0.5-5 mol%. Process according to Claims 1 and 2, characterized in that the carboxylic acids used are stearic acid, palmitic acid or a mixture thereof, preferably stearine or a mixture of acids resulting from the hydrolysis of lanolin and, as amines, in particular stearylamine. 4. Process according to claim 1, characterized in that after the copolymerization the pressure is reduced to atmospheric and the melt is maintained at 250-270 [deg.] C. for at least 30 minutes and further processed in a manner known per se to a granulate or pulverized.