DD205441A1 - PROCESS FOR PREPARING HIGH VISCOSES OF ANTIELECTROSTATIC POLYAMIDE-6 MOLDING - Google Patents

Abstract

The invention relates to a process for the preparation of highly viscous, non - electrostatic polyamide - 6 molding compositions which are preferably used for the production of film hoses used in the food industry. The product is prepared by coupling in the melt of alternating olefin / maleic anhydride copolymers with OH-containing high molecular weight polyethylene or propylene oxides or saponified ethylene vinyl acetate copolymers with polyamide-6.

Description

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VEB Leuna-Werke Leuna, the u \\ B?

"Walter Ulbricht"

LP 8207

Title of the invention

Process for the preparation of highly viscous polyamide 6 antistatic polyols

Field of application of the invention

The erfindungagemäß produced products are used as molding compositions for the production of antistatic films, semi-finished products and injection molded parts.

Characteristic of the known technical solutions

Highly viscous polyamide 6 molding compositions with a relative solution viscosity of greater than or equal to 3.5 according to OJGL 20055 are prepared industrially in the main by postpolycondensation of hydrolytically produced polyamide-6 in the solid phase in an inert gas atmosphere at temperatures just below the melting point of the polyamide (DD). PS 91 566), It has also been proposed that the high-viscosity polyamides by crosslinking ^ fyev melt on an extruder

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with alternating olefin / MaleJLnsäureanhydrid copolymeric säte to produce (WP C 08 G / 222 193). The moldings, semi-finished products, foils, etc., which are produced by this process, accumulate very strongly electrostatically when dry. This leads z, B. in addition, that tube foils from these products can not be processed on non-specially equipped automatic ligation machines.

A variety of methods have now been described for antistaticizing polyamide-6 in grades used for fiber production. For this purpose, polymers of ethylene oxide or propylene oxide, whose O-H groups can be esterified, etherified or reacted with isocyanates, are incorporated during their preparation, after or during their processing (DD-WP 129 922, DD-AP 129 920, DE-OS 2 164 307, DE-OS 2 416 206), but products of this type are not highly viscous and can not be subjected to postcondensation, since the added products not only the chemical part of the Hachkondensation, but, especially at higher additions, their technical feasibility to disturb. In addition, special in a subsequent incorporation of the additives in the polyamide, not the washout is achieved, which is required in an application in the food industry. Each EP 0010938 proposes, among other things, to incorporate more or less fully saponified ethylene-vinyl acetate copolymers and maleic anhydride / olefin copolymers in polyamide for the production of impact-resistant polyamides. However, no alternating copolymers are used, and no higher-viscosity products are also produced.

Object of the invention

The aim of the invention is the preparation of a high-viscosity polyamide-6 with antistatic properties of the finished products prepared therefrom,

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Presentation of the invention

It was the task of an antistatic polyamide-6 by. Add appropriate products without thereby preventing the formation of a highly viscous product

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According to the invention, the object is achieved in that Poly-mid-6 a relative Lösungsviskoaität of less than or equal to 3 _t 4 with 0.5 to 8 % of a polymeric ethylene oxide and / or propylene oxide having an average molecular weight of 500 to 50,000, which have at least one free OH group and / or totally or partially saponified copolymers of ethylene with vinyl acetate having a starting ester content of 15 to 50% and 0H numbers of 100 to 350 mg KOH / g and melt indices of 1 to 200 g / 10 min (measured according to TGL 20 996 at 190 ° and 2 , 16 kp load), and 0.05 to 5 % of an alternating copolymer of maleic anhydride and an alpha-olefin

^ _{1 of} the general formula CIIo «G, in which R ₁ and R ₀ ai

phatic Kohlenwaaaerstoffreste represent one to ten carbon atoms and / or hydrogen or R _{1 is} a hydrogen atom and Rg is an ester or ether group, in the melt at temperatures up to 300 ⁰ C implemented. Polymers of ethylene oxide or propylene oxide are, for example, polymeric products of the above compounds which are etherified or esterified on one side with primary alcohols or carboxylic acids of C ₁ -C 10 or reaction products of primary or secondary amines or ammonia with ethylene oxide or with propylene oxide.

Particularly advantageous is the use of 1 to 3 % of a Äthylenoxidanlagerungsproduktes to primary amines, ie those polymers of ethylene or propylene oxide having 2 or 3 free OH groups and their average molecular weight between 1000 and 30,000, preferably 1000 to 10 000, lies;

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The copolymers of maleic anhydride with an alpha-olefin have an average molecular weight of 5000 to 500,000. They can be partially hydrolyzed, esterified or amidated.

Preferably, 0.1 to 1 % of an alternating propylene maleic anhydride copolymer is used. The reaction in the melt is expediently carried out in a single-screw or twin-screw extruder. The three components react with each other. In particular, the OH-containing polymers are connected via the maleic anhydride / alpha-olefin copolymer with the polyamide chain, wherein an additional increase in the relative solution viscosity is brought about by further crosslinking by polymers having more than one free OH group. The molding compositions produced in this way can be processed by injection molding or extrusion to form parts, semi-finished products and films. In particular, film hoses produced therefrom can be processed on automatic ligation machines without special equipment against static charge.

embodiments

Example 1 · .

In a mixer, 50 kg of polyamide-6 having a relative solution viscosity of 2.65 are mixed thoroughly with 200 g of an alternating maleic anhydride / propylene copolymer having an average molecular weight of 10,000. Thereafter, with further mixing, 1 kg of an adduct of ethylene oxide with palmitylamine having an average molecular weight of 1500 are added. Of this mixture are deformed and-strands to 4 kg / h in a laboratory twin-screw extruder of Werner and Pfleiderer ZSK 28 metered and melted under a vacuum degassing at 250 ⁰ C, which are cooled in a water bath and then granulated.

The product has a relative solution viscosity of 4.52. Without the addition of A'thylenoxidanlagerungsproduktes is

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only reached a viscosity of about 3.95. The Materiel can be blown into film tubes. The material is anti-electrostatic ·

Example 2

As in Example 1, 47.5 kg of polyamide-6 having a relative solution viscosity of 2.5, 200 g of an alternating maleic-acid anhydride / propylene copolymerate having an average molecular weight of 8000 and 2.5 kg of a partially hydrolyzed ethylene / vinyl acetate copolymer with a starting vinyl acetate Contents of 33% by weight and a residual content of 9 % with a melt index i = 54 g / 10 min. Intensively mixed. 30 kg / h of this mixture are extruded 60 mm screw diameter (D), length 25 D melted at 260 ⁰ C, deformed into strands, cooled and granulated. The granules can be processed into film tubes, which can be processed on the usual automatic binding machines without difficulty. In addition, these films can be welded particularly durable in contrast to films without the addition of the saponified copolymer.

Example 3

Starting materials as in Example 2. As an additive, 2.0 kg of a saponified Äthylenvinylacetatcopolymerisats with a Reatvinylacetatgehalt of 0.6 wt .-% and a melt index of i β 67 g / 10 min. used. The resulting granules can be easily blown into films that can be processed without disturbing electrostatic charge and also have good weldability.

Claims (3)

invention claim 1, Method for the preparation of liochvisiiose antielektro «. static Poljramid-6 Pormmassen, thereby. characterized in that polyamide-6 of a relative solution viscosity is less than or equal to. 3.4 with 0.5 to 8 % of a polymeric Äthy} .§noxids and / or propylene oxide having an average molecular weight of 500 to 50,000, which have at least one free OH group and / or totally or partially saponified copolymers of ethylene with Vinyl acetate having a starting ester content of 15 to 50% and OH numbers of 100 to 350 mg KOH / g and melt indexes of 1 to 200 g / 10 min and 0.05 to 5 % of an alternating copolymers of maleic anhydride and an alpha-olefin of the general Formula CHp »C, in which R and Ro are aliphatic carbon represent hydrocarbon radicals having from one to ten carbon atoms and / or hydrogen, or R ₁ is a hydrogen atom and R ₂ is an ester or ether group, is reacted in the melt at temperatures up to 300 ⁰ C, " 2. The method according to item 1, characterized in that 1 to 3% of Äthylenoxidanlagerungsproduktes of primary amines of molecular weight 1000 to 10,000 are used. 3 · Method according to items 1 and 2, characterized in that 0.1 to 1 % of an alternating propylene maleic anhydride copolymer is used ·