US1882070A - Treatment of materials containing natural silk - Google Patents

Description

Patented Oct, 11, 1932' UNITED GEORGE HOLLAND ELLIS, OF SPONDON, NEAR DERBY, ENGLAND, ASSIGNOR T0 CELANESE CORPORATION OF AMERICA, A CORPORATION OF DELAWARE TREATMENT OF MATERIALS CONTAINING NATURAL SILK No Drawing.

This invention relates to the treatment of fabrics or other goods or materials made of or containing natural silk with alkaline reagents.

It is well-known that treatment of materials containin natural silk with caustic alkali results in de degumming materials comprising natural silk it has been the practice to temper the action of caustic alkali by addition of other reagents such as sulphonated oil or to use instead of caustic alkali, alkaline reagents having a milder action, for example borax or sodium silicate.

I have now made the discovery that natural silk goods may be protected against the action of alkaline reagents by the simultaneous presence of cellulose esters. Provided that the latter be present in more than an insignificant percentage, the action of the alkali is almost wholly confined to the cellulose ester component, the natural silk remaining substantially unaffected. This discovery is very surprising since it would be expected that the natural silk already degummed or degummed by reason of the alkaline reagent would be acted upon by the alkaline reagent to produce a degradation in addition to saponification or. hydrolysis of the cellulose ester. This discovery may be most usefully applied in the treatment of mixed materials containing both natural silk and cellulose acetate or other cellulose esters. By treating such a mixed material with a .suitable alkaline reagent saponification of: the cellulose ester results with or without degumming of the natural silk but without degradation.

In the past in degumming thenatural silk of materials comprlsinghoth cellulose esters and natural silk care has been taken to avoid alkalinity suflicient to produce either degradation of the natural silk constituent or saponification or hydrolysis of the cellulose ester.

I have found moreover that the above property may be utilized to produce various colour efiects upon mixed materials containing both cellulose esters and natural silky For example, the material containing natural silk and superficially or partially saponigradation of the silk. In.

Application filed June 24, 1929, Serial No. 373,490, and in Great Britain July 9, 1928.

fied cellulose ester may be treated with dyestufi's, for instance some acid and direct cotton dyestuffs, having an aflinity for the natural silk and for cellulose materials to produce shades substantially even on the cellulose M ester and silk components.

Moreover I have found that the superficially or partially saponified or hydrolized cellulose esters retain their afiinity .for the insoluble colours especially devised for apm plication to cellulose esters and usually applied in solubilized or dispersed form, e.

the S. 'R. A: colours. By applying S1151 dyestufli's for dyeing the cellulose ester constituent of the mixed materials, diflerential 65 colouration is obtainable since the'natural silk is not in general dyed by these dyestufis. Furthermore the materials treated according to the present invention may be dyed both with the S. R. A. type of colour and 7" with the direct cotton type of colour so as to obtain a single shade on the natural silk due to the direct cotton colour and a compound shade on the cellulose ester component due to both types of colour. Again if de- 75 sired the -.mixed materials treated according to the present invention may be coloured with acid dyestuifs which resist or only slightly stain cellulosic materials and this type of dye may be applied in conjunction with any 30" tion or hydrolysis of the cellulose ester may on be employed, and furthermore salts or other electrolytes may be added thereto as has been proposed in prior saponification'processes. ,The treatment with an alkaline reagent may convenientlyand economically be or.

carried out in conjunction with the degumming of the natural silk by simple addition of the suificient quantities of alkali to the customary soap or soluble or sulphonated oil solution. Furthermore if desired dyeu stuifs may be incorporated such a solution provided they are compatible therew th,

for example the insoluble dyestuffs generally applied to cellulose esters in solubilized or dispersed form.

I have found that the best results in the saponification or hydrolysis are obtained if the liquor bath volume is adjusted so as to A woven crepe fabric consisting of equal weights of cellulose acetate and natural silk in the gum is suspended by means oif loops in a 1 bath containing 5 grams per ,litre of soap and a quaiitity of caustic soda equal to 10% of the weight of cellulose acetate present. The bath is then raised to 95100 C. and the goods treated for 3 hours, by which time the cellulose acetate is saponified approximately 10%, lustre being simultaneously modified. The natural silk is simultaneously fully degummed, loss in weight being normal, and handle and tensile strength fully equal to samples -degummed by methods familiar in the art. v

The cellulose acetate portion may now be dyed with the insoluble dyestuffs having selective afinity for that fibre, and the natural silk with acid dyestuffs having little or no afinity for cellulose acetate or regenerated cellulosic fibres. Thus a blue maybe obtained on the cellulose acetate by means of di- Inethyldiamino-anthrarufin, and an orange on the natural silk with Kiton Fast Grange G. (Colour, Index No. 27).

Example .9

A woven crepe fabric consisting of 1 part of degummed natural silk as weft and 2 parts of cellulose acetate as 'warp is treated at 80 C. in a 5 gram per litre soap solution containing 5% caustic soda on the weight of cellulose acetate (volume 200 1) A further 2 caustic soda is added after 1 hour, and a similar amount again after another hour mak- Treatment is continued for %1 hour longer, after which the fabricis lifted, rinsed and dried or otherwise treated as requisite. The cellulose acetate portion has now'been saponified approximately 10% and exhibits the modified dyeing and other properties of superficially or partially saponified cellulose acetate, whilst the natural silk retains its characteristic properties.

' While the invention has been described above more particularly with reference to the treatment of materials consisting of natural silk and cellulose acetate it may be applied rate or the products obtained by treatment of alkalized cellulose with esterifying agents, e. g. the product obtained with p-toluene sulpho-chloride and known as immunized cot ton and to materials containing other constituents in addition to natural silk and cellulose esters, for example cotton or other natural cellulose material, cellulose ethers, or 4 the cellulosic type of artificial silk, i. e. viscose, cuprammonium or nitrocellulose artificial silk. Such other constituents may be dyed or otherwise coloured with any of the usual dyestuffs therefor to produce further effects.

What I claim and desire to secure by Letters Patent is 1. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against theiaction of the alkaline reagents by effect ing the treatment in the presence of cellulose ester material.

2. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with a cellulose ester.

3. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with a cellulose ester, the reagents being sufliciently alkaline to produce partial saponification of the cellulose ester.

4. In the degumming of materials comprising natural silk with alkaline liquors, the

.step of protecting the natural silk against the action of the alkaline reagents bytreating it in the form of a mixed material with a cellulose ester.

5. In the'treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by effecting the treatment'in the presence of cellulose acetate material.

6. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with cellulose acetate. 7. In the treatment of materials comprising naturalsilk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with llll aeeaere ciently alkaline to produce partial saponification of the cellulose acetate.

8. In the degumming of materials comprising natural silk with alkaline liquors, the

step of protecting the natural silk against.

the action of the alkaline reagents. by treating it in the form (if a mixed material with cellulose acetate.

9. In the treatment ofmaterials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with a cellulose ester and subsequently colouring the material with a dyestuff having an afiinity for at least one of the constituents of the mixed material.

10. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with cellulose acetate and subsequently colouring the material with a dyestufl having an afiinity for at least one of the constituents of the mixed material. 11. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the action of the alkaline reagents by treating it in the form of a mixed material with a cellulose ester, the reagents being sufficiently alkaline to produce partial saponification of the cellulose ester and subsequently colouring the material with a dyestuif having an afiinity for both of the constituents of the mixed material.

12. In the treatment of materials comprising natural silk with alkaline liquors, the step of protecting the natural silk against the actlon of the alkaline reagents by treating it in the form of a. mixed material with cellulose icetate, the reagents being sufficiently alkaline to produce partialsaponification of the cellulose acetate and subsequently colouring the material with a dyestufi having an aflinity for both of the constituents of the mixed material.

In testimony whereof I have hereunto subscribed my name.

GEORGE HOLLAND- ELLIS.