CS215441B1 - A method of preparing polyamide-6, antistatically modified - Google Patents

Abstract

A method for preparing antistatically modified polyamide-6 and especially fibers facilitating the preparation by using for modification a low-melting polyetheramide with a melting point below 120 °C formed by a polycondensate of a mixture with a proportion of 85 to 97 wt. % alpha-omega diaminopolyethylene glycol with an average molecular weight of 800 to 4000 and a dicarboxylic acid with 4 to 12 carbon atoms or its ester in an amount of 1 to 1.2 equivalents per used diamino derivative of polyglycol, which is mixed with the monomer-caprolactam before hydrolytic polymerization, or in its initial phases.

Description

It is an object of the present invention to provide an antistatic modified polyamide-6 and polyamide fibers.

The preparation of antistatic modified polyamides is carried out in order to reduce electrostatic charge and thereby improve physiological properties and can be ensured by the addition of certain substances, so-called " modifiers into the polymer mass. Among these substances, polyetheramides occupy an important place.

They can be used to prepare modified polyamides and polyamide shaped articles having good antistatic properties and their scrub resistance. The prior art preparation of modified polyamides and molded polyamide products using modifiers of this kind consisted in that the mechanical blend of the modifier and the polymer, generally in granular form, was remelted under agitation to form a modified polyamide granulate suitable for preparing fibers.

In a second possible process, such antistatic polyamides are prepared by mixing the melts of both components, i. molten polyamide and mo-1 diffuser.

The disadvantages of the prior art processes for the preparation of polyamides modified with polyether amides are the cumbersome technological processes and the demands on the form and method of modifier modification.

In the first process, a hardly available granular or, alternatively, powder modifier is needed. Given the melting point of the polyether amides and their partially tacky nature, the preparation of the powder modifier on a technical scale is virtually impossible.

Similarly, the preparation of a granular modifier for the same reasons is a very difficult and technically unresolved problem.

In the second process, the mixing and metering of the components for preparing the modified polymer at a temperature above their melting point and under an inert atmosphere is a serious problem. In addition, this process requires special additional equipment to the production lines and is practically feasible only when combining the production of the modifier and the preparation of the modified polymer in one production line.

A substantially simpler process for preparing a modified polyamide is the process by which modifiers are added to the monomer. However, the modifiers for such a process must have appropriate physical and chemical properties. In particular, if the addition of the modifier to the monomer is to be an advantage over its addition to the polymer, then the modifier used must be melted at a relatively low temperature generally below or slightly above the melting point of the monomer.

Furthermore, during the polymerization, they must not lose the modifying efficiency, nor be separated from the molten monomer and the polymer formed. In addition, of course, they must meet all the basic requirements for compliant modifiers with antistatic efficiency.

A suitable technically feasible method of preparing antistatic polyamide-6 is to admix 1-6% wt. Polyether amide characterized in that a low-melting polyether amide having a melting point below 120 ° C, composed of polycondensate with a predominantly high proportion of 85-97% by weight, is used for the modification. α, ω-diamino polyethylene glycol with a diameter of mol. with a weight of 800-4000 and a dicarboxylic acid having 4-12 carbon atoms or an ester thereof, and by adding such a modifier to the caprolactam monomer before the hydrolytic polymerization is carried out or in the initial stages of polymerization.

This procedure has other advantages over the older procedures. It places lower demands on the quality of the modifier. Use of a modifier with a high content of α, ω-diamino polyglycol t. j. with a high proportion of its active ingredient makes it possible to reduce the total amount of its addition. This reduces the risk of adversely affecting the processing properties of the polymer.

On the other hand, the proposed process compared to the processes which claim the application of a mixture of unreacted starting polyether components. ramidic modifier, or its individual of the constituents does not lead to condensation reactions that are associated with loss of mobility and hence antistatic activity.

The protection against such participation of the proposed modifier in the polymerization process is amide bonds, which under the given conditions can only be changed by preamidation, which proceeds substantially slower than the compared reactions of the unreacted components of the modifier.

The main advantage of the proposed method of modification by adding suitable polyether amides to the polyamide-forming monomer is that it is possible to 'work' at relatively low temperatures, making it possible to <technically simple to apply the proposed process without the use of particularly complex manufacturing equipment. Moreover, the low temperature reduces the possibility of deteriorating the properties of the modifier by thermal decomposition and oxidation reactions, and thus the deterioration of the processing, mechanical and coloristic properties of the modified polyamide and fibers.

The process for the preparation of the modified polyamide and the modified molded polyamide products according to the present invention demonstrates without the aid of the present invention. the following examples.

Example 1

Before polycondensation, 3% of a polyetheramide type modifier with a high content of 91% - diamino polyethylene glycol, prepared by condensation from diamino polyglycol with a relative average mole, was added to epsilon caprolactam. weight 1610sl, 12 equivalent amounts of adipic acid and corresponding amounts corresponding to the percentage composition of epsilon-caprolactam.

To the mixture was added 3% water and 0.22% benzoic acid. The mixture was polymerized in an autoclave at 253 ° C for 6 hours.

The melt of the modified polymer after polymerization was extruded in the form of strings, which were chilled to a granular polymer after cooling by continuous passage through water tubs. This was freed of monomer by extraction with water and dried. The prepared granulated modified polyamide was spun through a 12-hole tube at a take-off speed of 1300 m / min.

The fibers were pulled to a 1: 2.7 ratio. The fibers had a mechanical strength of 4.3 cN / dtex and a ductility of 36%.

The fibers had a significantly lower tendency to generate static charge than unmodified fibers. The value of elstat. the tension on the surface of washed modified fiber knitted fabrics did not exceed 25% of the charge value on unmodified fiber knitted fabrics. With multiple repetitions, the antistatic effect is partially reduced, but the charge value does not exceed half the charge value of the unmodified fibers.

Example 2 215441

Procedure as in Example 1 except that the modifier was added in an amount of 4.5%. The antistatic properties of the fibers have increased, but the technological certainty of its preparation and its workability has deteriorated.

Example 3

Procedure as in Example 1 except that the modifier was added in an amount of 2%. Elstat voltage value. the charge was higher than in Example 1. However, it did not exceed 30% of the charge value of the unmodified fibers.

However, the reduction in antistatic efficiency in repeated wash was faster than the fibers in Example 1.

Example 4

The procedure as in Example 1. However, a modifier containing 86% diamino polyglycol was used to prepare the modified polyamide. The preparation of the modifier / caprolactam monomer mixture was partially made difficult by the higher melting point of the modifier. The properties of the fibers were similar to those of Example 1.

Claims (1)

4 average mol. with an equivalent amount of adipic acid and an appropriate amount corresponding to the percentage composition of epsilon-caprolactam. 3% water and 0.22% benzoic acid were added to the mixture. The mixture was polymerized in a 253 ° C autoclave for 6 hours. After the polymerization was finished, the modified polymer melt was extruded as strings, which were cut into granular polymer after cooling by continuous passage of the overflow tub. This was stripped of the monomer by water extraction and dried. The prepared granulated modified polyamide was spun through a 12-hole tube at a tensile speed of 1300 m / min. The fibers scored at 1: 2.7. Fibers small mechanical strength 4.3 cN / dtex and ductility36%. Fibers have a minor lower tendency to formiate charge than unmodified fibers. the tension on the surface of the modified fiber knits did not exceed 25% of the charge value on the unmodified fiber knits. In multiple repetitions, the antistatic effect is partially reduced, but the charge value does not exceed half the charge value of unmodified fibers. Example 2 215441 The procedure as in Example 1 except that the modifier was added at 4.5%. The antistatic properties of the fibers have increased, but the technological certainty of its preparation and its workability has increased. Example 3 Procedure as in Example 1 except that the modifier added at 2%. The voltage of the electrostatic charge was higher than in Example 1. However, it did not exceed 30% of the charge value of the unmodified fibers. However, the reduction in antistatic efficiency in repeated washing was faster than in Example 1. Example 4 Procedure as in Example 1. However, a 86% diamino polyglycol modifier was used to prepare the modified polyamide. The preparation of the monomer-caprolactam monomer mixture was partially complicated by the higher melting point of the modifier. The properties of the fibers were similar to those described in Example 1. A method of preparing polyamide-6, antistatically modified with an admixture of 1-6 wt. polyether amide, characterized in that a low melting polyether amide with a melting point below 120 ° C consisting of a polycondensate mixture with a predominantly high proportion of 85-97% by weight is used for the modification. α, ω-diamino-polyethylene glycol with an average mol. with a weight of 800-4000 and a dicarboxylic acid of 4-12 carbon atoms or an ester in an amount of 1 - 1.2 equivalents to the diamino derivative of the polyglycol used, said blender being mixed with the ε-caprolactam monomer prior to carrying out the hydrolytic polymer or in the early stages of polymerization.