IL28029A - Process for rendering cellulosic fibers flame-resistant - Google Patents

Description

KOLD COHN & CO.

PATENT TEL- AVI 406"o ."i n .1'jK'in PATENTS AND DESIGNS ORDINANCE Specification PROCESS FOR RENDERING CELLULOSIC FIBERS FLAME-RESISTANT π'κη '•-I 'D1? nu'on n'jpn I' nn We CIBA LIMITED, of Klybeckstrasse l l, Basle, Switzerland, a body corporated according to the laws of Switzerland, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement: It has been found that cellulosic fibrous materials, especially textile materials, can be advantageously rendered flame-resistant by applying to said materials an aqueous preparation containing at least one phosphorus compound of the fo in which R represents a hydrogen atom, an alkyl radical or alkenyl radical, _j and R2 each represents a substituent linked with the oxygen atom through a carbon atom, and X represents a hydrogen or halogen atom, a methyl group or a group of the formula -GHg-CO-NH-CHg-O-R (where R has the above meaning), whereupon the material is dried and at a pH value below 3 subjected to a heat treatment at a temperature above 100°C.

Phosphorus compounds of the formula (1), containing one or more than one carboxylic acid methylolamide group and a wide variety of substituents 1 and R2, are known (see, for example, British Patent 1 011 72 - AHL 104). Preferred compounds are those of the formula 0 It (2) E3~°\ .0H2-0H-C-NH-CH2-0-R« in which R^ represents an alkyl or halogenalkyl radical, that is to say a chloralkyl or bromalkyl or chlorobromalkyl radical, or a halogenalkenyl radical containing at most 4- carbon atoms, or a halogenophenyl radical; X represents a methyl group or preferably a hydrogen atom and R* stands for a hydrogen atom, 0 II The present process is preferably carried out with the use of aqueous preparations which contain compounds of the formula (l) and whose pH value is already below 3» preferably from 1.4 to 2.5. To achieve these values, a strong mineral acid such as sulphuric, nitric or preferably hydrochloric acid is added to the preparations. Instead of the acids themselves, especially hydrochloric acid, there may be used their compounds from which the corresponding acids are readily formed in water, for example even without heating, by hydrolysis. As relevant examples there may be mentioned phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, thionyichloride, sulphurylchloride, cyanuric chloride, aeetylchloride and chlora-cetylchloride . When these compounds are hydrolyzed, they furnish exclusively acid fission products, for example cyanuric acid and hydrochloric acid. It may prove advantageous to use instead of one of the aforementioned strong acids acid mixtures corresponding to the hydrolysis products of one of the compounds just mentioned, thus, for instance, instead of hydro-chloric acid alone a mixture of hydrochloric acid and ortho-phosphoric acid corresponding to phosphorms pentachloride, the two acids being advantageously used at a molecular ratio of 5 : 1. When ammonium chloride is used, the pH value of the aqueous preparations drops below 3 only when hardening is performed above 100°C.

Apart from the compounds of the formula (1) and the additives needed to establish the requisite pH value the further ingredients· It is possible to add an aminoplast, for example a possibly etherified methylolurea or methylol-melamine, but such addition is surprisingly unnecessary in the present process (which is performed at the indicated, low pH values) to achieve a flame-resistant finish fast to washing and, taking into consideration the impairment of the tear strength generally resulting from a treatment with an aminoplast, it is generally not recommended.

On the other hand, it may be advantageous for the preparation to contain a copolymer, obtained by polymerisation in an aqueous emulsion, from (a) 0.25 to 10 of an alkaline earth metal salt of an α,β- -ethylenically unsaturated monocarboxylic acid, (b) 0.25 to 3 of an N-methylolamide or N-methylolamide ether of an α,β-ethylenically unsaturated monocarboxylic or dicarboxylic acid, and (c) 99.5 to 60% of at least one further copolymerizable compound.

These copolymers and their manufacture are likewise known (see British Specification 983 205 - Case 5 08/E). The additional use of such a copolymer may have a beneficial effect upon tfhe tear strength and abrasion fastness of the fibrous materials treated.

As a further additive, which offers advantages in some cases, there may be mentioned a softening dressing agent, for example an aqueous polyethylene emulsion or ethylene-copolymer emulsion.

The amount of compounds of the formula (1 ) added to the aqueous preparation is advantageously chosen 8,0 that 20 to 40% this connection it must be borne in mind that commercial textile materials from native o regenerated cellulose are capable of absorbing from 50 to 120% of an aqueous preparation The amount of additive required to adjust the hydrogen ion concentration to a maximum value of 3 depends on the selected pH value itself and on the type of substance added; in each individual case there is a mandatory minimum. A certain excess over this minimum is in general beneficial. A large excess offers no advantage and may even be harmful.

When a polymer of the indicated kind is further added to the preparation, it is advantageous to use a small quantity thereof, for example 1 to 10% of the weight of the compound of the formula (1). The same is true of a possibly added softener of which likewise 1 to 10% are indicated.

The preparation is applied in the known manner to the cellulosic fibrous material, for example linen, cotton, synthetics, spun rayon or blends of these materials and others such as wool, polyamide fibres or polyester fibres. The process is preferably applied to piecegoods which are impregnated at room temperature on a conventional padder containing the preparation.

The impregnated fibrous material must then be dried, advantageously at a temperature of up to 100°0. It is then subjected to a dry heat treatment at a temperature above 100°C for example from 150 to 200°C and preferably from 150 to 180eC this heat treatment may be the shorter the higher the temperature used is. This heat treatment takes, for example, 2 to 6 minutes at a temperature from 1 0 to 180°0. Since during this formed at the same time. It has been found that these volatile fission products must be continuously removed from the materia to ensure that the desired effect is obtained in full. The apparatus used for the heat treatment must, therefore, be selected accordingly. Good results are obtained with those apparatus in which the prescribed temperature is kept constant and fresh air is introduced continuously, while the air charged with the volatile substances formed is expelled. Such apparatus, for example so-called turbofixers or jet-fixers, are known.

Subsequent washing with an acid acceptor, preferably with aqueous sodium carbonate solution, for example at 40°C u to the boiling temperature and for 3 to 10 minutes, is necessary in view of the strongly acidic reaction medium.

As mentioned above it is possible to achieve by the present process flame-resistant finishes which will withstand several washes or dry cleaning operations and that do not impair too much the textile-mechanical properties of the material treated, especially when the above-mentioned copolymers and softeners are addtionally used.

Example 1 A mercerized and bleached cotton fabric is padded with an aqueous solution containing per litre 360 g of 3-(dimethyl-phosphono)-propionic acid methylolamide, 2 g of phosphorus trichloride and 40 g of an aqueous polyethylene emulsion of 20% strength. The pH value of the padding solution is 1.6.

The fabric is then expressed to a weight increase of 75%» dried at 60 to 70°C, and then treated for 4½ minutes at 155°0 in a turbofixer. Finall it is washed in a boilin bath minutes. The fabric thus treated is flame-resistant and remains so even after 5 washes for ¼ hour at 95°C in. a washing liquor containing per litre 5 g of soap and 2 g of anhydrous sodium carbonate.

Instead. of phosphorus trichloride the padding liquor may contain per litre 1.5 g of phosphorus pentachloride, or 2.2 g of phosphorus oxychloride, or 2.6 g of thionylchloride or 10.6 g of hydrochloric acid of 33% strength, in which case the pH values of the padding liquors vary from 1 to 2. The flame-resistant finishes thus obtained are likewise fast to washing.

Example 2 An aqueous padding liquor containing per litre 360 of 3-(dimethylphosphono)-propionic acid methylolamide and 40 g of an aqueous polyethylene emulsion of 20% strength is neutralized with sodium hydroxide so that its pH value is 7·0· Then hydrochloric acid is added until the pH value drops to 1.4, for which purpose 12.7 ml of hydrochloric acid of 37·5% strength are required.

A mercerized, bleached cotton fabric is padded with this liquor to a weight increase of 75%, dried at 60 to 70°C and then treated for 4)έ minutes at 1 5°0 in a turbofixer or for 2 minutes at 180°C in a jet-fixer. The fabric is then washed for 5 minutes in a boiling sodium carbonate solution of 0.2% strength, rinsed in cold water and once more dried. The fabric, which now has a flame-resistant finish, retains it even after having been repeatedly washed.

Similar, good results are obtained when the amount of Example 3 Flame-resistant finishes fast to washing are obtained by proceeding as described in Example 2 , except that the following compounds are used to establish the requisite pH values instead of first neutralizing the padding liquor and then adding hydrochloric acid to it: Additive strength Amount g/litre pH value 1 H2S0 98% 4.35 2.0 2 HN03 62% 8.85 1 .7 3 cyanuric chloride 16.1 1.9 4 acetylchlori.de 6.85 1.7 100% 1.2 2.1 HOI 37.5% 4.25 6 85% 1.3 2.0 HC1 37. 5% 5.4 7 85% 1 .65 2.1 HOI 37.5% 4.2 8 H2S05 7.: 18.7 1 .9 HOI 37.5% 4.25 Example 4 The process described in Example 1 is performed with the use of the padding liquors Nos. 9 to 13 ί Padding liquor 9 10 11 12 1 3 3-(d:Lmethylphosphono)-propionic acid methylol- - g/litre 360 360 360 360 360 . amide aqueous polyethylene emulsion of 20% strength - g/litre 40 40 40 40 40 aqueous copolymer emulsion g/litre 40 40 +) g/litre ammonium chloride The aqueous copolymer emulsion used is a 7 emulsion of a polymer from 78 parts of acrylic acid-n-butyl ester, 14.5 parts of vinylidenechloride , 7.0 parts of acrylic acid methylolamide and 0.5 part of calcium acrylate.

The flame-resistant finishes obtained are quite fast to washing, especially when, as in Nos. 0 and 12, the copolymer is used additionally.

In comparative tests carried out as described above the drop in. tear strength was measured; the results are summarized in the following Table: un treated N°9 N°10 N°11 N°12 Ne13 Breaking load kiloponds/2.5 cm pQ p., p2 p^ p4 . p5 warp 26.9 20.2 24.8 21 .2 24.5 21 .9 weft 36.8 29.0 31 .7 28.3 32.2 28.7 breaking load in % m lOOpn warp 100 92 79 91 weft 100 84 75 85

Claims (1)

1. HAVING NO particularly described and ascertained they nature of our said invention and in what manner the same is to be performed we declare that what we claim is 1. Process for rendering cellulosic ibrous materials flame-resistant, wherein the said materials are treated with an aqueous preparation containing at least one phosphorus compound of the formula 0 n R.-O . .CH~-CH-C-NH-CHo-0-R in which R represents a hydrogen atom, an alkyl radical or alkenyl radical, ^ and R2 each represents a substituent linked with the oxygen atom through a carbon atom, and X represents a hydrogen or halogen atom, a methyl group or a group of the formula -CHg-CO-NH-CHg-O-R- (where R has the above meaning), whereupon the material is dried and at a pH value below 3 subjected to a heat treatment at a tempera¬ methylolamide· to Claim 1 2 or ized 5 . Process according to any one of claims 1 to 4, characterized in that the aqueous preparation contains a copolymer, . obtained by polymerization in aqueous emulsion, from (a) Ο.25 to 10 of an alkaline earth metal salt of an α,β- ethylenically unsaturated monocarboxylic acid, (b) Ο.25 to 30$ of an N-methylolamide or N-methylolamide ether of an a, β-ethylenically unsaturated monocarboxylic or dicar- boxylic acid, and (c) 99.5 to 60$ of at least one further copolymerizable compound. 6. Process according to any one of claims 1 to 5* characterized in that the pH value of the aqueous preparation is below 3. 7 · Process according to claim 6, wherein the pH value of the aqueous preparation is from 1 .4 to 2 .5 · 8 . Any material provided with a flame-resistant finish according to any one of claims 1 to 8 . Dated this 22nd May, 1967