US2323751A - Process of treating pelts or furs - Google Patents

Description

Patented July 6, 1943 PROCESS or TREATING PELTS on FURS Siegfried Gottfried, Budapest, Hungary, assignor to Pannonia (London) Limited, London, England, a limited-stock company of England No Drawing. Application July 27, 1937, Serial No. 156,005. In Hungary November 24, 1936 1 Claim.

The treatment of pelts is normally effected by combing, shearing and ironing the hair of the pelt. In this way, it is possible to straighten out even the strongly curled hair of certain pelts, such as for example lambskins, and to impart to them a lustre so that it is possible produce imitations of rare furs from lambskins.

Such improved lambskins or the like-suffer, however, from the considerable disadvantage that the mutual position of the hairs of the furs, and particularly however the effects produced by the treatment, such as the straightening, lustre and feel of the hair only persist as long as the furs are not exposed to the action of moisture or damp air. As soon, however, as the furs become moist or damp they lose the properties imparted to them by the improving treatment, and the original properties, particularly the curling of the hair, absence of lustre and therefore unimpressive appearance, return again. Thus, for example, an imitation nutria made from lambskin having a beautiful lustre and soft feel is scarcely distinguished from the original unimpressive lampskin when the fur is moistened and dried again.

It has now been found that, by suitably treating the pelts it is possible to impart to them properties, more particularly, lustre, silkiness and out in any stage of the preparing process, but

preferably in any treatment stage before the last treatment with pressure and heat.

The pressure and heattreatment may be carried out for example in heated presses or by means of curling irons or by ironing. In the case of ironing, straightening of the hair is effected simultaneously.

In place of formaldehyde, it it also possible to employ substances such as paraformaldehyde or bisulphite-aldehyde which are adapted to split off aldehydes. The treatment may be carried out by using acroleine (acryl-aldehyde) as working agent.

It has furthermore been found that the degree of the effect depends upon the concentration of the formaldehyde solution employed. In general, the desired effect is secured more rapidly and more completely by employing concentrated solutions, that is to say, containing for example aldehyde solutions also increases with the duration of the action, particularly in the case of dilute solutions.

In view of the fact that concentrated formaldehyde solutions weaken and embrittle the grain of the skin, it may in certain cases be expedient to prevent the access of aldehyde to the skin. This may be effected for example by introducing fat into the skin during tanning (chamois tanning), and furthermore, the skin or the leather may be impregnated or coated with a solution of a water-repellent substance (for example paraflin wax) before the formaldehyde treatment. If these steps are carried out, the formaldehyde treatment may be effected even by immersion of the pelts in formaldehyde solutions or by means of formaldehyde vapours without the skin being damaged, even with high formaldehyde concentrations.

Another method of preventing the access of aldehyde to the skin comprises applying the formaldehyde solution by coating, spraying or brushing on the hair in such a manner that the formaldehyde solution does not reach the roots of the hair but only wets the upper part, about of the length of the hair.

Examples 1. Raw lambskins washed in the usual manner and tanned in any desired manner, are sheared to uniform length on a shearing machine and dried, that is to say, they are white dressed. The hair of the pelts thus prepared is straightened by combing or carding. A 30% formaldehyde solution (750 cc. of 40% formaldehyde solution per litre of solution) is then applied in such a manner that the solution does not reach the roots of the hair. The pelts are stored for 3 to 12 hours and then, if desired after dyeing are dried and are straightened and stretched on brushing and ironing machines. The treatment with formaldehyde solution and the subsequent straightening may also be repeated one or more times.

2. As according to Example 1 with the difference that dyeing is only carried out after final ironing.

3. Raw lambskins are prepared in known manner for tanning, are chamois tanned and the skin is likewise made supple in known manner. The hair is combed and then shorn. The pelts are now steeped in a 15% formaldehyde solution for 24 hours and then-if desired after rinsing-are dried, washed, stretched and dyed in known manner and finally th hair is straightened and stretched on brushing machine and shearingironing machines.

4. The raw pelts are washed, shom and dried, whereupon the hair is treated with formaldehyde solution of a suitable concentration and is dried and if desired the formaldehyde treatment is repeated one or more times. Finally, the pelt are tanned and finished.

If the formaldehyde solution is to penetrate as far as the roots of the hair, it is preferable suitably to protect the grain from the action of the formaldehyde.

5. An alum tanned pelt is white dressed and the flesh-side is then coated with a solution of parafiin wax in carbon tetrachloride. The pelts thus pre-treated are steeped for about 12 to 24 hours in a 40% formaldehyde solution and then finished. After the formaldehyde treatment, the paraffin wax introduced into the hide may be removed again in a suitable manner.

6. The skins, after a pre-treatment. are treated with formaldehyde according to one of the above examples and instead of being ironed are dried in a press with simultaneous heating, or are treated with formaldehyde, dried and finally hot pressed. The dyeing of the hair may take place before or after the formaldehyde treatment.

7. The hair treated with formaldehyde is curled by means of curling irons or the like. The spaces between the curls may be hot pressed with smooth or patterned pressing surfaces. In this way, it is possible to produce imitation broadtail which is resistant to water.

The foregoing examples do not exhaust the possible ways of carrying out the invention. The formaldehyde treatment may be carried out in any desired stage of the treatment steps. It is also possible to effect the formaldehyde treatment simultaneously with dyeing or in a step preparatory to dyeing. It is also possible to finish dressing the pelts entirely, that is to say to carry out all the steps heretofore usual (tanning, combing, ironing) and then allow formaldehyde vapours to act on the furs. Dyeing may be effected before or after the treatment with formaldehyde vapour.

The important advantage of the pelts improved in the manner described is that they are practically perfectly resistant to moisture in the sense that when immersed in water, or even after being kept in water for days, they exhibit substantially the same improved appearance as before moistening. This fact considerably extends the possibilities of employing such pelts or furs. The high resistance to moisture also makes it possible to carry out dyeing of the pelts or furs after the treatment with formaldehyde and ironing, which may be desirable in certain cases. The pelts or furs improved according to the invention possess an enhanced lustre their hair is softer and decidedly silkler than that of pelts treatment in other respects in the same way but without formaldehyde.

The invention is based on the knowledge that the effects described above are only produced when the action of the formaldehyde or other aldehydes on the hair of the pelts is combined with a simultaneously or separately effected action of mechanical pressure and heat.

The present application i a continuation in part of my previous application, Serial No.

93,918, filed August 1, 1936.

What I claim is:

In the treatment of pelts and furs, the process which comprises treating the hair of a pelt by contacting the hair with the vapors of formaldehyde in quantity sufficient to cause the eventual setting of the hair and, while at least residues of said aldehyde are still present on said hair, sub- Jecting the hair to the simultaneous action of mechanical pressure and heat, thereby producing setting of the hair.

SIEGF'RIED GOTTFRIED.