WO1993015138A1

WO1993015138A1 - Method of improving the heat-insulation properties of polyamide 6.6 filaments, and filaments produced by this method

Info

Publication number: WO1993015138A1
Application number: PCT/CH1993/000015
Authority: WO
Inventors: Erwin Lerch
Original assignee: Rhone-Poulenc Viscosuisse S.A.
Priority date: 1992-02-03
Filing date: 1993-01-21
Publication date: 1993-08-05
Also published as: TW210368B; EP0578794A1; JPH06507215A; BR9303967A

Abstract

Described is a method of improving the heat-insulation properties of Cu/I-based polyamide using systems containing 0.1 to 1.0 % by wt. of quaternary phosphonium iodides which cannot be easily washed out. After rinsing and dyeing, filaments produced by this method exhibit a loss in tear strength, determined in an 8 h/177 DEG test, of less than 17 % relative to untreated fibres. In addition to filaments, the method is suitable for use with fibres, sheets and moulded articles.

Description

Process for improving the thermal protection of polyamides 6.6 filaments and those produced therewith

filaments

The invention relates to a method for improving the heat protection of polyamide 6.6 filaments based on Cu / l and filaments produced therewith.

Heat protection systems for polyamide 6.6 on Cu / l resp. Cu / I / Br bases are known (US-A-3 947 424). The iodides are in the form of alkali, alkaline earth or substituted or. contain unsubstituted ammonium iodides. They are easy to wash out of the heat-protected nylon 66 yarns with warm water. For use as a tire thread or -kord, the washability of the heat protection additives is meaningless because tire yarns during processing - apart from brief impregnation with the dip solution - are not subject to wet finishing operations and are enclosed in rubber.

DE-AS-12 61 668 and CH-A-484 227 heat stabilizers made of copper, phosphorus and iodine compounds for polycaprolactam (polyamide 6) for the production of technical threads are known. Quaternary phosphonium iodide is used e.g. a triphenylmethylphosphonium iodide with a hot water solubility around 150 g / 1 H2O. This can be done from such a thread

REPLACEMENT LEAF Wash out iodide relatively easily and it quickly loses its tensile strength after heat treatment in air (eg 8 h / 177 ° C) after washing.

However, if such heat-protected technical yarns are subjected to any hot water treatment for other areas of application, e.g. Potassium iodide completely completely and the copper partially washed out. Under hot water treatments steam treatments with condensate formation, hot water relaxation and / or fixation, washing out of the spinning preparation and yarn resp. Piece dyeing in aqueous baths can be understood. Due to the extensive to complete loss of the iodide content with a reduced copper residual content, the yarn has largely lost its thermal oxidation protection after hot water treatment.

It is also known that secondary aromatic amines, the NH group of which can also be a ring member of a heterocycle, provide non-washable thermal protection for polyamides (for example alkylated phenothiazine derivatives; 5,5-dimethylacridane; N, N'-diarylphenylene) diamine). However, such aminic antioxidants either result in non-white threads or those which change color very quickly and strongly, especially in the light, which excludes them for many fields of application.

With the hardly discoloring antioxidants of the sterically hindered phenol type, the requirements in the high temperature tests cannot be met even in high concentrations. One such test is the heating of the yarn or of a fabric made from it for 8 hours at 177 ° C. or for 30 days at 10 ° C. in air.

There are also heat protection systems based on Cu / l with complete or partial replacement of the iodide

REPLACEMENT LEAF Copper (I) benzothiazolyl-2-mercaptide, 2-mercaptobenzimidazole and unsubstituted benzimidazole have become known. The additives mentioned do not give any white threads in the presence of copper, for example as Cul, and are not able to reduce the washability of water-soluble iodides, such as Lil, NaI or KI, added in a known manner from the yarn.

The object of the invention is to provide a method which makes it difficult to wash out heat protection for polyamides based on Cu / l /.

Another task is to reduce the tensile strength loss of an industrial yarn through the improved heat protection.

This object is achieved according to the invention by adding 0.2 to 1.0% by weight, preferably 0.3 to 0.8% by weight, of a guaternary phosphonium iodide to the polyamide.

Surprisingly, it has been possible to produce heat-protection systems for polyamide 6.6 filaments based on Cu and I which are difficult to wash out with very specific quaternary phosphonium iodides and which improve the tendency to discolour the thread.

In particular, those phosphonium iodides have proven to be suitable whose solubility in boiling water (96-98 ° C.) is less than 10.0 g / 1, preferably less than 0.8 g / 1.

It is advantageous if the quaternary phosphonium iodides are melt-soluble, i.e. are homogeneously distributable in a polyamide melt. The addition is advantageously carried out in the polyamide melt before extrusion.

The phosphonium iodide can also the granules before Melting powdered.

It is advisable to add the phosphonium iodide together with Cul.

The quaternary phosphonium iodides, the use of which is the subject of the present invention, contain one or more triarylphosphoniono, preferably triphenylphosphoniono groups and comprise the following 2 types:

- Type 1 with the general formula [Pt ^ PR ^] ⁺ I-, in which

Ph = phenyl and R ¹ can optionally be an aryl, arylalkyl or alkyl radical. In the aryl and arylalkyl radicals, the aryl groups can also carry up to three substituents, for example tertiary butyl or other alkyl groups, -OH, -Cl, -Br or I. Preferably R ^{1 is} a phenyl, benzyl, benzhydryl, trityl - or a generally unbranched alkyl radical having at least four, preferably at least ten, carbon atoms. Suitable examples of iType 1 are tetraphenylphosphonium iodide, benzyltriphenylphosphonium iodide, benzhydryl triphenylphosphonium iodide and trityl triphenylphosphonium iodide.

- Type 2 with the general formula [Ph ₃ PR ² -PPh3] ²⁺ 2l ^_ , wherein R ^{2 is} optionally an o-xylylene, p-xylylene or an alpha, omega-alkanediyl radical. Preferred substances of type 2 are 1,4-bis (triphenylphosphonionomethyl) benzene diiodide (= p-xylylene-bis-triphenylphosphonium iodide) and 1,1O-bis (triphenylphosphoniono) decane diiodide (= decamethylene-bis -triphenylphosphonium iodide).

After washing out / blind dyeing, the filaments have a tensile strength loss of less than 17% at 8 h / 177 ° C

- Test based on the unheated filaments. Compared to the loss of tensile strength of the known filaments, a significant improvement is achieved.

The application of the method is not limited to filaments and fibers, but is also intended for foils and other shaped articles.

The invention will be described in more detail by means of examples.

Preparation of the σuaternary phosphonium iodides

The quaternary phosphonium iodides mentioned are prepared in a known manner by reacting triphenylphosphine with the corresponding aliphatic mono- or dihalohydrocarbons in the individual case, such as solvents, such as N, N-dimethylformamide, chloroform and others. If one does not start from an iodine alkane, which immediately provides the desired salt, but from chlorinated or bromocarbons, then the quaternary phosphonium chlorides or bromide obtained from hot aqueous solution can be obtained by double reaction with NaI or KI into the much heavier ones convert soluble iodide.

The quaternary phosphonium iodides used according to the invention are used together with a copper compound, preferably copper (I) iodide, in heat-protection systems for aliphatic polyamides which are difficult to wash out, the Cu content in the product being between 10 and 100 ppm, preferably between 15 and 65 ppm and the I content between 300 and 1500 ppm is selected, the I content comprising the iodine contained in the quaternary phosphonium iodide and in the Cul optionally used. The molar ratio l / Cu is always at least 2 and is preferably chosen between 3 and 25.

REPLACEMENT LEAF The quaternary phosphonium iodides can either be powdered onto finished granules or added to the polyamide at the extruder inlet. If the granules do not already contain a copper compound, one is applied to the granules at the same time, copper (I) iodide being particularly preferred because this forms polyamide-melt-soluble diiodocuprates (I) with the quaternary phosphonium iodides. This reaction may take place well below the polyamide melting point.

example 1

0.018% by weight of copper (I) iodide and 0.44% by weight of trityl-triphenylphosphonium iodide as a powder mixture in a ring gear mixer were added to 0.02% by weight of TiC ^ and otherwise additive-free polyamide 66 granules drummed up. The granules were then spun into threads with a final dtex 78f13 titer. The contents of Cu and I in the thread are 60 respectively. 1000 ppm.

Example 2

0.018% copper (I) iodide and 0.386% by weight benzhydryltriphenylphosphonium iodide as a powder mixture were tumbled onto a 0.05% by weight TiO.sub.2 and otherwise additive-free polyamide 66 granulate in a ring gear mixer. The granules were then spun into threads with a final dtex 78f13 titer. The contents of Cu and I in the thread are 60 respectively. 1000 ppm.

A thread of the same titer, made of polyamide 66 with the same amount of Cu and I, but used in the autoclave in the form of copper (II) acetate and potassium iodide, was used as a comparison material.

REPLACEMENT LEAF Circular knit stockings were produced from both nylon 66 threads, which were subjected to simultaneous aging tests by heating in air both in the raw state, after washing and after blind dyeing. By measuring the tensile strength of threads made from circular knit stockings before and after the aging tests in the three states mentioned (raw; after washing out; after washing out + blind dyeing), the progress according to the invention is shown on the basis of the tensile strength losses shown in Table 1.

The thermoresistance test is carried out as follows: Filaments or a knitted fabric are hung tension-free in a chamber (Binder type Led heating cabinet) with a closed air circulation system and treated at 177 ± 1 ° C for 8 h. After the test period, the samples are measured at room temperature.

REPLACEMENT LEAF

*) Comparative goods described in Example 1 in the text **) for 30 min at 70 ° C. in deionized water, each containing 1 g / l sodium carbonate and Kieralon B (trademark of the company BASF); rinsed without alkali. ***) Blind dyeing = test under dyeing conditions without dye for 60 min at boiling temperature in acetate buffer pH 5 +/- 0.05 (1.5 g / 1 CH ₃ COONa + 0.65 ml 98-100% CH3COOH / I) , Fleet 1:80

With polymer melt-soluble, thermostable quaternary phosphonium iodides, the "washed out" and "blind-dyed" conditions were surprisingly achieved for the first time in the 8 h / 177 ° C. test compared to the known polyamide, which resulted in a greatly improved thermal resistance.

REPLACEMENT LEAF

Claims

1. Procedure for improving the thermal insulation of polyamide 6.6 filaments based on Cu / l, characterized in that 0.2 to 1.0% by weight of a quaternary phosphonium iodide is added to the polyamide 6.6 melt.

2. The method according to claim 1, characterized in that a melt-soluble benzyltriphenylphosphonium iodide, a benzhydryltriphenylphosphonium iodide or a trityl-triphenylphosphonium iodide is used as the quaternary phosphonium iodide.

3. The method according to claim 1, characterized in that the quaternary phosphonium iodide has a solubility <10 g / 1 H ₂ 0 at 96-98 ° C.

4. The method according to claim 1, characterized in that the phosphonium iodide is powdered onto the granules.

5. The method according to claims 3 and 4, characterized in that the phosphonium iodide is used together with Cul.

6. Filaments made of a polyamide 6.6 with improved heat protection, characterized in that the filaments, after washing out / dyeing, show a loss of tensile strength in the 8 h / 177 ° C. test of less than 17%, based on the untreated filaments.

REPLACEMENT LEAF