GB2031940A - Cleaning and deoiling of textile materials using perchloroethylene - Google Patents

Abstract

Method of anti-stain redeposition of stains on textiles in natural, synthetic, or artificial fibres or their mixtures, during operations of dry cleaning or de-oiling by means of stabilised perchloroethylene. It is characterised by the fact that to this perchloroethylene is incorporated a sufficient quantity of one or more than one nitrile chosen in the groups of those whose boiling point is less than or equal to 130`C and of those forming with perchloroethylene an azeotrope whose boiling point is lower than 130`C, in order to obtain an anti-greying effect. Application of this method to textile materials, for example in cotton, wool, polyester, polyacrylonitrile or polyamide.

Description

SPECIFICATION Cleaning and deoiling of textile materials using perchloroethylene The present invention relates to a process for the dry-cleaning and deoiling of textiles, with the aim of preventing the soiling matter from redepositing onto a substrate made of natural, artificial or synthetic fibres or a mixture of these fibres, and thus of keeping the soiling matter of this substrate in suspension in the liquid bath during the cleaning or deoiling process as well as to the liquid bath used.

It is well known that, during operations for drycleaning or deoiling woven or knitted textiles using perchloroethylene, the soiling matter extracted from the textiles tends to redeposit onto the textiles, especially when the perchloroethylene is not regenerated regularly; this accentuates the phenomenon of "greying" the textiles, which is particularly noticeable on white or light-coloured fabrics.

The factors which can affect this redeposition are numerous and the complexity of the phenomenon is due principally to the diverse nature of the fibres which are generally present in the same cleaning bath, and on the relative humidity of the ambient atmosphere.

Various anti-redeposition agents have already been proposed for washing textiles in an aqueous medium, in particular cellulose derivatives.

When cleaning in an organic solvent medium, it is known that certain boosters have an antiredeposition action, in particular the substituted oxazines and amides having more than 10 carbon atoms, which are described in French Patent No.

1,386,783 and its Addition No. 89,341.

However, whether these boosters are those employed in an organic medium or those employed in an aqueous medium, they exhibit the major disadvan tage that they cannot be distilled and must therefore be freshly added after every operation for regenerating the dirty solvent.

The object of the present invention is to reduce or prevent the redeposition and thus limit very considerably the "greying" phenomenon during the drycleaning or deoiling of textiles made of synthetic, artificial, natural or mixed fibres, whilst ensuring that the anti-redeposition agent can be recovered and re-used each time the bath is regenerated.

We have found, surprisingly, that it is possible to reduce soil redeposition very substantially by using, in the suitably stabilised perchloroethylene, at least one nitrile having a boiling point which is less than or equal to 1300C (under normal pressure), or which forms, with the perchloroethylene, an azeotrope having a boiling point which is less than or equal to 130"C.

Accordingly the present invention provides a process for counteracting soil redeposition during drycleaning or deoiling using suitably stabilised perchloroethylene, which comprises adding, either to the perchloroethylene and/orto the dry-cleaning or deoiling bath, at least one nitrile having a boiling point which does not exceed 1300C, preferably from 95 to 1200C, or which forms, with the perchloroethylene, an azeotrope having a boiling point which is less than or equal to 130 C, preferably greaterthan 80"C.

Suitable such nftriles include those represented by the general formula: R-C=-N in which R represents a C,-Cs alkyl, Ct-C6 alkenyl or C3-Cs cycloalkyl group.

Examples of suitable nitriles include the following, which can be used singly or as mixtures of at least two compounds: acetonitrile, but - 3 - ene nitrile, cisand trans-crotononitrile, butyronitrile, isobutyronitrile and valeronitrile.

Propionitrile is preferably employed.

The degree of the anti-redeposition effect depends on the nitrile in question and on its concentration. In general, the most effective nitriles, such as acetonitrile and propionitrile, exert an appreciable antiredeposition effect in an amount of about 0.2% by weight in the perchloroethylene, whereas with others, such as chloroacetonitrile, the optimum effect is generally observed at proportions of about 6% by weight. However, it is preferred to use nitriles, the effect of which becomes appreciable or optimum at proportions of 1 to 2.5% by weight in the perchloroethylene.

As is well known it is generally necessary to sta bilise the perchloroethylene against oxidation when the perchloroethylene comes into contact with, for example, air or metal surfaces and/or is exposed to light, heat and/or humidity. Any stabiliser known for this purpose, in particular those which are compatible with the nitriles can be used; these include inter alia: butylene oxide, triethylamine, tert.-butanol, N-methylpyrrole, n-butanol, diisobutylene, isopropyl acetate and epichlorohydrin, used singly or in mixtures of at least two of these compounds.

The anti-redeposition process according to the invention can also involve the addition of products which are generally employed in dry-cleaning, such as cleaning boosters, in particular anionic, cationic or nonionic surface-active agents such as: alkylsulphonates, alkylarylsulphonates, more particularly Ca dodecylbenzenesulphonate, products resulting from the reaction of ethylene oxide with fatty alcohols and fatty acids, sulphates of fatty alcohols, petroleumsulphonates, alkyl polyglycol ethers, and alkylphenyl polyglycol ethers, more particularlyoxyethyleneated nonylphenol containing 12 mols of ethylene oxide, brighteners, finishing agents, anti-static agents and water repellents.These additives can be employed in the usual proportions, for example from 1 to 10 g per litre of bath, insofar as this is compatible with the presence of the nitriles.

Furthermore, the process of the invention can be carried out in the presence of water in proportions up to, say, 5 to 6%, and more particularly from 2 to 3%, by weight relative to the textiles to be cleaned.

This water can originate from the moisture present in the textiles themselves a ndlo r in the commercial cleaning boosters which generally contain 4 to 30%, and usually from 8 to 14%, of their weight of water.

Sometimes, additional amounts of water, for exam ple 2 to 4% by weight relative to the textiles to be cleaned, can be added to the cleaning bath contain ing the boosters, in order to improve the cleaning effect with respect to so-called "lean" stains.

The process is applicable to textile materials made of, inter alia, cotton, wool, polyester, polyacrylo nit- rile and polyamide.

The present invention also provides a composition or bath suitable for dry-cleaning or deoiling of textiles made of natural, artificial, synthetic or mixed fibres, during the actual dry-cleaning or deoiling operations, which comprises suitably stabilised perchloroethylene, optionally containing up to 6% by weight of water, relative to the textiles to be treated, and customary additives, more particularly cleaning boosters and anti-static agents, each in an amount of 1 to 10 g per litre of the said composition, the composition also containing from 0.2 to 6%, and preferably 1 to 2.5%, by weight, relative to the said composition, of at least one nitrile having a boiling point which is less than or equal to 1300C, preferably from 95 to 1200C, or which forms with the perchloroethylene, an azeotrope having a boiling point which is less than or equal to 1300C and preferably greater than 80"C.

The method of operation which makes it possible to evaluate the "greying" of the textiles was carried out using soiling matter which is representative of the soiling matter usually present on clothes; it had the following composition by weight: carpet dust passed through a 26 mesh sieve (mesh size of 0.63 mm) 100 spent oil from a motor car engine 100 carbon black ground in its own weight of SAE 30 engine oil 4 oxyethylenated castor oil containing 10 molecules of ethylene oxide 5 distilled water 50 stabilised perchloroethylene 155 The white textile samples used were as follows: 100% polyester (268 g/m2) 100% polyamide - 6,6 (170 glum2) 100% polyacrylonitrile (220 glum2) 100% wool (280 g/m2) 100% cotton (110 g/m2).

In order to evaluate the "greying" of the textiles, the following were placed successively in a laboratory drum-type machine: 225 cm2 of each of the abovementioned textile samples, and 1 litre of the stabilised perchloroethylene composition in which 0.5 g of the soiling matter defined above had been dispersed.

After a treatment lasting 5 minutes at about 25"C, the textiles were spun and dried at 60"C in a ventilated oven.

Each of these samples, treated and more or less "greyed" in this way, was subjected to a determination of its reflectance index using a "Reflectionmeter 670" of Messrs. "Photovolt" (United States of America) fitted with a green filter.

The apparatus was set at 100 for each untreated original textile and the reflectance of each "greyed" sample was measured. The greying is the lower, the closer is the reflectance to 100.

The following Examples further illustrate the present invention; the indicated percentages of the constituents of each composition are expressed by weight relative to the composition in question.

In all the Examples, reference is made, by way of a control, to the measurements of the reflectance index for samples of textiles treated under the same conditions with stabilised perchloroethylene which did not, however, contain the anti-redeposition agent.

EXAMPLES 1 to 10 By following the method of operation explained above, the "anti-greying" or anti-redeposition effect of a composition based on initially stabilised perchloroethylene, to which different proportions of various nitriles were incorporated, was examined.

The starting perchloroethylene was stabilised with 0.0025% of triethylamine, 0.002% of N-methylpyrrole and 0.02% of n-butanol.

The following Tables I to IV summarise the results obtained.

For each series of Examples, these Tables include a control experiment carried out with a composition which did not contain any nitrile of the invention.

TABLE I

- Fibre I i Poly- olyacryl Polyalnide CtOiln0PnOS Cotton Wool ester nitrile 6,6 Control 89 95 1 71 70 91 1 Perchloroethy lene + 2.5 96 95.5 99 97 95 98 of acetonit rile 2 Perchloroethy lene + 5 % of 99 100 97. 97.5 99 acetonitrile TABLE II

Fibre rn Composi otton Wool Poly- |Wool|P y-|Poly & ry- IPolyacry- Polyamide tion ester lonitrile 6,6 Control 83 90 71.5 0 75 93 Perchloroethy lene + 5 % of 93.5 98 97 96.5 99 propionitrile 4 Perchloroethy lene + 5 % of 92,5 98,5 95.5 95 99.5 butyronitrile TABLE III

Fibre - Fibre otton Fibre ~ Poly- Polyacry- Polyamide amples Coinposi- ester Wool lonitrile 6,6 tion Control 88 94 74 1 70 97.5 Perchloroethy S lene + 5 96 of 85 92 88 80 96.5 chioroaceto nitrile Initrile 6 Perchloroethy- 91 98.5 97.5 96.5 100 lene + S % of crotononitrile TABLE IV

- Fizz Fibre Poly- Polyacry- olyamide Ex otton Wool ester lonitrile polyp Control 85 94 70 75 85.5 7 Perchioroeth lene +1.25 87 98 90.5 82 98 of propionlt rile 8 Perchloroethy-l lene + 2.5 % < 90 98.5 93 85 98.5 propionitrile | TABLE IV (continuation)

Ex- \ Fibre Poly- Polyacry- Po de amples Compo a Cotton Wool ester lonitrile Polyanide ester lonitrile 6,6 tion Control 92. 95 68 72 94 9' IPerchloroethy lene + 5 % of 89 99. 93 83 99 valeronitrile Control 89 93 76 73 96 10 Perchloroethy- 90 97 97 88 100 lene + S 46 of isobutyro nitrile These Tables demonstrate the significant improvement in the anti-redeposition effect when the specified nitriles are incorporated in the stabil ised perchloroethylene, compared with the controls consisting of stabilised perchloroethylene by itself.

Claims (18)

1. A process for counteracting soil redeposition during dry-cleaning or deoiling of a textile made of natural, synthetic or artificial fibres or mixtures thereof using stabilised perchloroethylene, in which the perchloroethylene contains at least one nitrile which has a boiling point which does not exceed 1300C, or which forms, with the perchloroethylene, an azeotrope having a boiling point which does not exceed 130 C, as anti-redeposition adjuvant.

2. Process according to claim 1 in which the nitrile has a boiling point of 95 to 1 200C, or forms, with the perchloroethylene, an azeotrope having a boiling point which is greater than 80"C.

3. Process according to claim 1 or 2, in which the nitrile has the formula: R-C=-N in which R represents a C1-Cs alkyl, C2-C6 alkenyi or C3-C5 cycloalkyl group.

4. Process according to claim 1, 2 or 3 in which the perchloroethylene contains 0.2 to 6% by weight of the anti-redeposition adjuvant.

5. Process according to any one of claims 1 to 4, in which the perchloroethylene contains 1 to 2.5% by weight of the anti-redeposition adjuvant.

6. Process according to any one of claims 1 to 5, in which the adjuvant is propionitrile.

7. Process according to any one of the preceding claims in which the perchloroethylene contains up to 6% by weight of water based on the weight of the textile.

8. Process according to any one of the preceding claims in which the perchloroethylene is stabilised with one or more of butylene oxide, triethylamine, tert. butanol, N-methylpyrrole, n-butanol, diisobutylene, isopropyl acetate and epichlorohydrin.

9. Process according to claim 1 substantially as described in any one of Examples 1 to 10.

10. A textile whenever treated buy a process as claimed in any one of the preceding claims.

11. A composition suitable for dry-cleaning or deoiling textile material which comprises stabilised perchloroethylene, and 0.2 to 6% by weight of at least one nitrile having a boiling point which is less than or equal to 130"C, or which forms, with the perchloroethylene, an azeotrope having a boiling point which is less than or equal to 130"C.

12. A composition according to claim 11 in which the nitrile has a boiling point of 95 to 1 200C, or forms with the perchloroethylene, an azeotrope having a boiling point which is greater than 80"C.

13. A composition according to claim 11 or 12 in which the nitrile has the formula: R-C=-N in which R represents a C1-C5 alkyl, C2-C6 alkenyl or C3-Cs cycloalkyl group.

14. A composition according to any one of claims 11 to 13 in which the nitrile is propionitrile.

15. A composition according to any one of claims 11 to 14 in which the perchloroethylene is stabilised with one or more of butylene oxide, triethylamine, tert. butanol, N-methylpyrrole, n-butanol, diisobutylene, isopropyl acetate and epichlorohydrin.

16. A composition according to any one of claims 11 to 15 which contains a customary dry-cleaning additive in an amount from 1 to 10 g/l.

17. A composition according to claim 11 substantially as described in any one of Examples 1 to 10.

New claims or amendments to claims filed on 22 Nov 1979 New claim:

18. A composition according to claim 11 which consists of stabilised perchloroethylene, 0.2 to 6% by weight of the said nitrile, up to 10 g/l of customary dry cleaning additive and water.