US2301263A - Manufacture of artificial textile materials - Google Patents

Description

Patented Nov. 10, 1942 UNITED STATES PATENT GFFECE MANUFACTURE OF ARTIFICIAL TEXTILE MATERIALS No Drawing. Application November 29, 1939 Serial No. 306,704 In Great Britain December 12, 1938 6 Claims.

This invention relates to improvements in the manufacture of artificial textile materials in yarn, fabric or other form, and in particular to the improvement of the properties of textile materials containing cellulose acetate or other orame derivative of cellulose.

Various attempts have been made to improve the properties of textile materials containing partially esterified or etherified organic derivatives of cellulose by further esterification, particularly with a view to rendering them more resistant to water and heat and to modifying their solubility in organic solvents. Thus, it has been proposed to employ inorganic acid derivatives, for example thionyl chloride, silicon tetrachloride and phosphorous oxychloride and anhydrides or halides of mono and poly-carboxylic acids, both of the aliphatic and aromatic series, for example acetic acid, benzoic acid, succinic acid, adipic acid and phthalic acid.

Whilst these known methods are generally capable of effecting a certain amount of esterification of the cellulose derivative materials, it has been found that they are subject to various disadvantages. For example, esterification may be accompanied by a serious deterioration in the textile properties of the materials treated, for example the tenacity or extension, particularly when acid halides are employed. In order to avoid this deterioration it has been proposed in some cases to neutralise the hydrohalide acid formed and in other cases to use the acid halides diluted with gaseous media. It has also been proposed to dry the cellulose derivative materials in order to reduce the degrading action of the hydrohalide acid.

If a cool iron at a temperature, for example, of about ZOO-220 C. is employed, no trouble is experienced with normal cellulose acetate fabrics, but the principal object of the present invention is to make it possible to use a hotter iron and to avoid glazing, scorching or other troubles.

By subjecting cellulose acetat materials to acetylation their melting point may be increased to about 300 C. but this is not always accompanied by an equally great improvement in the ironing point. Attempts to improve the ironing point by esterifica-tion with dicarboxylic acid an hydrides and chlorides have not yielded any betironing point, can be obtained by esterification with halides of polybasic acids if a substantially higher temperature is employed for esterification than has hitherto been employed in processes of further esterification with derivatives of monoor poly-basic acids. In order to obtain these improved results, it has been found necessary to effect esterification at a temperature above C., the best results being obtained, in general, at a temperature of C. to 170 C., e. g. or C. It would have been expected that at such high temperatures the hydrohalide acid formed would have a destructive effect on the materials subjected to esterification and it is surprising that this has been found not to be the case.

The process is applicable to textile materials in general which contain organic derivatives of cellulose, particularly organic derivatives of cellulose containing about 2-2.5 substituent radicles per C6Hl005 nucleus. The materials may for example be staple fibres or staple fibre or continuous filament yarns in the form of hanks or present in woven, knitted or netted fabrics.

The halides which it is preferred to employ are those of adipic acid and phthalic acid, particularly the chlorides. Examples of other halides which may be employed are oxalyl, melonyl, and succinyl chlorides and carbonyl, thionyl and sulphonyl chlorides.

Esterification in accordance with the process of the present invention makes it possible to improve very considerably the ironing point of the materials. Thus, for example, While processes previously described using halides of polybasic acids only yield products having an ironing point of about 220230 C., which is practically the same as that of the starting materials, by means of the present process an ironing point of 280-300 C. or even more may be obtained. The melting point of the products may be raised for example to 340 C. or more. The process also renders the materials more water-repellent and less soluble or even insoluble in organic solvents.

The ironing point referred to in this specification is the maximum temperature of the base of an iron of the modern household electrical type which can be moved over a fabric at a speed of one foot per second without scorching or weakening the fabric.

The materials to be esterified are preferably freed from any oil or other conditioning agent by scouring and drying.

The esterification may be effected by heating the cellulose derivative materials in a solution of the acid halide dissolved in an organic liquid which is a non-solvent for the materials and it has been found that the nature of this liquid, though it does not appear to take any part in the reaction, is also of importance. The organic liquids which have been found to be of particular value are hydrocarbons, particularly kerosene, toluene, xylene and mesitylene. Mixtures of organic liquids, for example a mixture of 60% kerosene and 40% xylene, may also be employed. The concentration of the acid halide in the organic liquid may be low, for example 1 or 2%, or considerably higher, for example 10, or The volume ratio of liquid medium to textile materials should be high, for example, be 40 or :1, and may with advantage be even higher, e. g. 100:1 or 500:1, particularly if the production of products of high tenacity is important.

The esterification medium may also contain a proportion of polybasic acid anhydride, e. g. about 24%.

In order to obtain products having the optimum properties as regards tenacity, it is desirable that the materials employed, including both the fabric or other to be esterified and the reagents, should be anhydrous. Fabrics and other materials may be dried for example in a hot air oven, while xylene or other diluent may be dried by treatment with a suitable reagent, for example anhydrous sodium sulphate. It is also desirable that the hydrohalide acid, a substantial amount of which is formed in the early stages of the reaction, should be allowed to escape as quickly as possible. Fabrics may, for example, be treated on a. winch, at least in the early stages of the reaction, in order to avoid the formation of pockets of hydrohalide acid. In the later stages the amount of acid evolved is generally less and such precautions become less necessary. The removal of hydrohalide acid formed may be assisted by bubbling nitrogen or other inert gas through the liquid during the reaction.

The reaction may be carried out in a closed vessel. In general, however, it is better to remove hydrohalide acid as it is evolved. This may be effected by the use of an apparatus fitted with a refiux condenser, the reflux conditions being such that hydrohalide acid split off escapes by way of the condenser while the other reagents present in the reaction medium are condensed and returned to the reaction vessel. Preferably, however, the whole of the distillate is removed and condensed. In addition to their other advantages, the organic liquids referred to are especially valuable, since they boil Within the temperature range which has been found to give the best results and control of the temperature conditions is thus facilitated.

Products having substantially improved properties may be obtained by carrying out the esterification process for a comparatively short period, for example 1530 minutes, or even less, e. g. 5 minutes, and in general it is found that a longer period than one or two hours is not necessary and does not result in any substantial further improvement in the properties of the products.

After completion of the reaction, the materials should be well washed to free them from the constituents of the reaction medium. For example, they may be washed first with a liquid which is miscible with the constituents of the esterification medium. When xylene is used as non-solvent diluent a suitable liquid is acetone or carbon tetrachloride. The materials may then be washed successively with a dilute solution of sodium carbonate, with dilute acid, for example dilute acetic acid, and with water.

The following are examples of the production of textile materials having an improved ironing point and other improved properties according to the process of the present invention:

Example 1 Hanks of cellulose acetate yarn having a high tenacity obtained by stretching cellulose acetate yarn in wet steam at superatmosphere pressure are scoured and dried and are then immersed in an esterification medium containing 1% of adipyl chloride and 99% of toluene, the volume ratio being 50:1. They are boiled for about 2-5 minutes and are then washed with carbon tetrachloride, air-dried and washed with 1% of sodium carbonate solution at 25 C. for about 20 minutes and then washed in water. Finally they are washed in cold 1% acetic acid for about 5 minutes, then in hot water and dried at about 110 C.

Example 2 A woven fabric made of yarn of commercial acetone-soluble cellulose acetate is scoured and dried and then immersed in an esterification medium containing 2% of adipyl chloride and 98% of xylene, the volume ratio being 50: 1. It is then heated for about 30 minutes at 140 C. On completion of the reaction the fabric is washed with boiling acetone and dried. It is then secured in an alkaline soap bath, washed with water and again dried.

Example 3 A woven fabric made of yarns of commercial acetone-soluble cellulose acetate is scoured and dried and is then immersed in an esterification medium containing 20% or phthalyl chloride and of mesitylene, the volume ratio being 50:1. It is then heated for 2 hours at about 165 C. On completion of the reaction the fabric is washed in benzene, air dried, immersed in a 1% solution of sodium carbonate at 25 C. for about 20 minutes and then washed in water. It is next washed in cold 1% acetic acid for about 5 minutes, washed in hot water and dried at about 110 C.

Example 4 Example 5 A woven fabric made of yarns of commercial acetone-soluble cellulose acetate is scoured and dried and is then immersed in an esterification medium consisting of 10% of succinyl chloride and of toluene, the volume ratio of medium to fabric being 50:1. The materials are boiled in the medium for 3 hours. At the completion of the reaction the fabric is washed in benzene, air dried, immersed in a 1% solution of sodium carbonate at 25 C. for about 20 minutes and then washed in water. It is then Washed in cold 1% acetic acid for about 5 minutes, washed in hot water and dried at about C.

Example 6 A woven fabric made of yarns of commercial acetone-soluble cellulose acetate is scoured and dried and is then immersed in an esterification medium containing 10% thionyl chloride, 5% pyridine and 85% of toluene, the volume ratio being :1. It is then boiled for 3 hours. On completion of the reaction the fabric is washed and dried as described in Example 5.

Example 7 An undyed fabric made of cellulose acetate yarn is turned by a winch in a bath of the following composition:

Per cent Xylene Phthalyl chloride 3 Phthalic anhydride 2 The bath is kept boiling at about 140 C. and the winch treatment is continued for 1 hour. The fabric is then removed from the winch and completely immersed in the boiling bath for 3 hours. On removal from the bath, it is plunged immediately into boiling acetone to free it as rapidly as possible from the constituents of the reaction medium and is finally given an antistatic finish of 1% wax from an acetone solution. The most suitable wax for this purpose has been found to be japan wax. If shrinkage occurs during the reaction, the fabric may, after esterification, be stretched to its original dimensions by stentering.

The resistance of the fabric to boiling water and boiling soap solutions is greatly improved and it can be subjected to treatment with such r solutions for considerable periods without damage or delustring occurring. The esterified product can be dyed in the ordinary manner, for example with dispersions of water-insoluble dyestufis. On account of the resistance to delustring, dyeing may be carried out at the boil and improved fastness thus obtained.

In each of the above examples heating is effected using an ordinary condenser, so that the distillate containing hydrohalide acid is not returned to the esterification medium. The products obtained are insoluble in acetone and chloroform and have a considerably increased melting and safe ironing point. The organic derivative of cellulose materials for which the process is particularly valuable are cellulose acetate materials, especially those made of acetone-soluble cellulose acetate. Other organic derivatives of cellulose materials which may be treated are materials containing cellulose propionate, butyrate or benzoate, or ethyl or butyl cellulose.

Having described our invention, what we desire to secure by Letters Patent is:

1. Process for improving the properties of artificial filaments, yarns and other textile materials containing organic derivatives of cellulose which contain free hydroxy groups, which comprises esterifying them with a dicarboxylic acid halide dissolved in an organic liquid which is a nonsolvent for said organic derivatives of cellulose at a temperature above C. under such conditions that their structure is retained.

2. Process for improving the properties of artificia1 filaments, yarns and other textile materials containing acetonesoluble cellulose acetate, which comprises esterifying them at a temperature above 100 C. with a solution of a dicarboxylic acid chloride in a solvent medium comprising a liquid hydrocarbon which is a non-solvent for said cellulose acetate under such conditions that their structure is retained.

3. Process for improving the properties of artificial filaments, yarns and other textile materials containing acetone-soluble cellulose acetate, which comprises esterifying them at a temperature between and C. with an esterification medium comprising adipyl chloride dissolved in a liquid hydrocarbon which is a non-solvent for said cellulose acetate under such conditions that hydrochloric acid formed is removed from the esterification medium, the volume ratio of esterification medium to textile materials being at least 50:1.

4. Process for improving the properties of artificial filaments, yarns and other textile materials containing acetone-soluble cellulose acetate, which comprises esterifying them at a temperature between 110 and 170 C. with an esterification medium comprising phthalyl chloride dissolved in a liquid hydrocarbon which is a nonsolvent for said cellulose acetate under such conditions that hydrochloric acid formed is removed from the esterification medium, the volume ratio of esterification medium to textile materials being at least 50: 1.

5. Process for improving the properties of artificial filaments, yarns and other textile materials containing acetone-soluble cellulose acetate, which comprises esterifying them at a temperature between 110 and 170 C. with an esterification medium comprising succinyl chloride dissolved in a liquid hydrocarbon which is a nonsolvent for said cellulose acetate under such conditions that hydrochloric acid formed is removed from the esterification medium, the volume ratio of esterification medium to textile materials being at least 50:1.

6. Process for improving the properties of artificial filaments, yarns and other textile materials containing acetone-soluble cellulose acetate, which comprises esterifying them with a dicarboxylic acid halide dissolved in toluene at a temperature above 100 C. under such conditions that their structure is retained.

HENRY DREYFUS. ROBERT WIGHTON MONCRIEFF.

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