US2282417A - Treatment of artificial materials - Google Patents

Description

Patented May 12, 1942 TREATMENT or anrmcmr. MA'rEarALs David ,James Hadley, Banstead, Surrey, -and Thomas Jackson, Spondon, near Derby, England, assignors to Celanese Corporation of America, a corporation of Delaware No Drawing. Original application May 8, 1940,

Serial No. 333,936. Divided and this application December 27, 1940, Serial No. 372,005. In

Great Britain May 23, 1939 2 Claims.

This invention relates to the treatment of artiflcial materials, and more particularly to processes for improving the properties, especially the extensibility, of artificial filaments, threads, yams, fabrics, ribbons and the like made of or containing an organic derivative of cellulose. This application is a divisional of our application S. No. 333.936, filed May 8, 1940.

It is known that it is a matter of considerable importance to weaving, knitting, twisting and other textile operations that filaments, threads,

yarns, and like'materials should have a substantial extensibility, preferably an extensibility of 10 to 12 or 15% or more. It has been disclosed in US. Patent No. 2,058,422 that the treatment of artificial materials having a basis of an organic derivative of cellulose withorganic solvents, swelling agents' or latent solvents, in the absence of tension suflicient to stretch the materials, serves to increase their extensibility. The selectionof the agents to be employed in this process is a matter of great importance and is determined by a number of factors involving elaborate research. The most important consideration, which weighs very heavily with the manufacturer, is that of reproducibility or control of results, and this is a particularly important matter when dealing with textile fabrics and L like materials, since quite small variations in physical characteristics, as cially extensibility, occurring over the leng"th* =o such materials are the filaments or other materials are under no tension or under only a slight tension so that they are substantially free to shrink under the influence of the treatment agent. It the agents are applied while the materials are under relatively high tension, the tension should subsequently be reduced or removed so that the materials are allowed to shrink while still under the influence oithe agents.

The treatment agent maybe employed alone or in admixture with other suitable agents, e. g.

the lower alkyl formates or methyl acetate. Suitable diluents are, for example, glycol, glycerol and other hyd'roxy compounds which are substantially without action on the materials. Preferably,. however, water-immiscible liquids are used as diluents, examples of which are benzene, toluene, xylene and other cyclic hydrocarbons, benzine, petroleum ether, kerosene and'other aliphatic hydrocarbons, carbon tetrachloride, perchlorethylene and other chlorinated or halogenshownup very clearly in" fabrics formed there from, e. g. by the faults which arise from uneven tension duringthe fabric-forming operation.

The over-all efilciency of the agents, their tox-' icity, and economic factors generally also come into consideration.

We have now found that propylene chloride ated compounds which are inert or substantially inert'towards the cellulose derivatives. Again, relatively high boiling diluents, e. g. tetrahydronaphthalene and decahydronaphthalene, may be employed. It will be understood, however,; that in general, diluents are not employed with the propylene chloride. I The concentration in which the treatment agent is employed and the temperature of workingwill depend upon the particular cellulose derivative which is present in the filaments or other materials to be treated, upon the physical characteristics of those materials and upon the degree of modification of the physical characteristics which is desired. Preferably, the shrinkage eiiected does not exceed about 20 or 25% and it is generallymost advantageous to efiect a shrinkage of 10 to 15%'. Shrinkage may be restricted by suitably modifying the treatment medium, as regards composition, concentration and/or temperature, and/or by treating the materials while they areunder sufiicient tension to prevent more than the desired shrinkage, the

the process with any particular materials, provided, of course, that the temperature of treatof cellulose are subjected, in the absence of tension sufilcientto stretch them, to the action of propylene chloride,v

Preferab' the treatment is carried out while like made of or containing an organic derivative f 'sion with a medium consisting of tension being maintained so long as the materials remain under the influence of the treatment agent.

When treating materials having a basis of acetone-soluble cellulose acetate, 'it is found that a satisfactory increase in extensibility can be secured by treating them in the absence of tenpure propylene chloride at about -78 C. I

The treatment agent according totheinvention may be employed in any of the methods described, for example, in U. S. Patents Nos. 2,070,583 and 2,058,422. The invention is of the greatest importance when applied to filaments, threads, yarns, fabrics, ribbons and the like containing or derived from high tenacity wet-spun materials or materials which have been stretched to 200% or more of their original length in hot water or wet steam or in a medium containing an organic solvent or swelling agent. It will be understood, however, that the: invention is not limited to the treatment of these materials, but is applicable generally to organic derivative of cellulose materials the extensibility of which it is desired to increase. It has further been found that the treatment agent according to the present invention imparts to staple fibres, particularly such as have been formed by cutting operations, a crinkled or crimped effect, which greatly enhances their spinning qualities.

'Reference ha been made above to materials having a basis of acetone-soluble cellulose acetate and the invention is of the greatest importance in connection with the treatment of such materials. However, materials made from other cellulose acetates or other esters of cellulose such as, for example, cellulose formate, propionate and butyrate, and mixed esters, e. g. cellulose acetopropionate and acetobutyrate, and also from celluloseethers, e. g. methyl, ethyl and benzyl cellulose, 'or from cellulose ether-esters, may be treated.

The following example illustrates the invention: 7

Example Dryspun cellulose acetate yarn, which has been stretched in wet steam to 1000% of its original length, is immersed for ten minutes at 76 C. in hank form in a bath of propylene chloride and allowed to shrink freely. The yarn is then washed with a low-boiling petroleum ether and dried in a current of warm air. The product is found to be uniformly shrunk and to have an improved extensibility.

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

1. Process for increasing the extensibility of artificial filamentary materials made of or containing an organic derivative of cellulose, which comprises subjecting such filamentary materials which have been stretched in the presence of wet steam to 1000% of their original length to increase their tenacity, to immersion for ten minutes at 76 C. in a bath consisting solely of propylene chloride, in the absence of tension sufficient to stretch said filamentary materials,

is increased.

2. Process for increasing the extensibility of artificial filamentary materials made of or containing cellulose acetate, which comprises sub jecting such filamentary materials which have been stretched in the presence of wet steam to 1000% of their original length to increase their tenacity, to immersion for ten minutes at 76 C.

in a bath consisting solely of propylene chloride,

DAVID JAMES HADLEY. THOMAS JACKSON.