US1957020A - Process for treating hides - Google Patents

Description

Patented May 1, 1934 UNITED srArEs raocnss FOR TREATING nmEs Herbert C. Reed, Stamford, Conn., assignor to Niacet Chemicals Corporation, a corporation of New York No Drawing. Application August 5, 1931,

Serial No. 555,370

13 Claims.

It is not always practical or feasible to conduct the treatment of the hides at the tannery in an uninterrupted sequence of operations. For this reason difficulties are encountered and losses occur due to the excessive putrefaction of hides which are allowed to stand between the various ticularly prevalent in hides which have been bated and which are not immediately processed further. Also, hides which are cured by salting are frequently unfit for the production of certain types of leather. For example, goat or kid skins from which white or light-colored leather is to be prepared may exhibit dark stains when tanned due to the presence of iron impuritiesin the salt with which the hides are cured. These iron compounds, if not entirely removed by repeated and protracted washings, are precipitated by the tanning agent and produce the objectionable stains.

These difliculties are largely avoided and novel benefits are derived from the application of the process of the present invention to the treatment of hides. The invention comprises, as

its principal feature of novelty, the application of treating agents not heretofore used for this purpose, and provides a simple, efficient and economical method for treating hides preliminary to tanning, all as more fully hereinafter described.

In practicing my invention, the hides, prior to or at the beginning of the tanning operations, are subjected to the action of an aqueous solution of paraldehyde (paracetaldehyde, (CHaCHO) a), or paraldol (CI-I3.CI-IOH.CH2.CHO) 2.

This treatment preferably occurs at the tannery, but, in the case of paraldehydamay occur immediately after flaying to replace other curing methods. In general, the hides are soaked with or without agitation in a bath containing from about 0.1% to 10% of either paraldehydepr paraldol based on the weight of the hides. Lower concentrations of the treating agent in the bath within the range indicated. and shorter immersteps in their treatment. This spoilage is parsion times maybe used if the bath is thoroughly agitated.

The effect of this treatment is multi-fold; it cleanses the hides, preserves the hides, plumps and fulls them, and, at least in the case of paraldehyde, exerts a beneficial preservative eifect upon certain vegetable tanning agents with which the hides may be subsequently contacted.

The application of the two treating agents of my invention follow each other in nearly all respects. The principal difierence is in regard to their use in conjunction with lime baths or lime depilatory treatments. Paraldol cannot be advantageously used simultaneously with such treatments because the paradol tends to react with lime. For this reason treatment with paraldol should be carried out after the hides have received the lime treatment, or treatment with other strongly alkaline materials.

The treatment with paraldehyde may occur at any time before tanning whether it is before, 'after or during lime treatment.

The following examples are illustrative of the invention:

I. One hundred pounds of wet goatskins were placed in a drum containing 3 pounds of paraldehyde and 9'7 pounds of water. The skins were thoroughly agitated in this bath for one hour and were then removed, allowed to drain, and were introduced directly into the tanning bath.

II. The process of Example I was varied by using 5 pounds of paraldehyde and pounds of water, and 30 minutes of agitation in the bath. The cleansing and plumping efiects secured in each case were very similar.

Hides which have.been subjected to a hating treatment may be immediately thereafter treated with paraldehyde in the manner described. This treatment cleanses and plumps the hides, and in addition, it prevents putrefaction, allowing the 95 hides to be transported or stored for considerable periods of time without spoilage. 4

Hides or skins which have been treated with paraldehyde or paraldol yield a higher grade of leather than similar hides which are tanned in the same manner without the use of these agents. The treatment of my invention plumps and fulls the hide, giving it rubbery feel, and causing it to become slippery an both the flesh and grain sides. The hides, after being treated with the 105 new treating agents, may be removed from the bath and then tanned or the tanning may be accomplished by adding a tanning agent to the treating solution thus avoiding the necessity of transferring the hides to another hath. no

From the foregoing description it will be apparent that modifications of my new process are possible and are included within the scope of the invention as defined by the appended claims.

I claim:

1. A process for treating hides preliminary to tanning operations which comprises soaking the hides in a bath containing asubstance of the group consisting of paraldehyde and paraldol.

2. A process for treating hides preliminary to tanning operations which comprises soaking the hides in a bath containing about 0.1% to 10% based on the wet weight of the hides, of a substance of the group consisting of paraldehyde and paraldol.

3. A process for treating hides to obtain leather therefrom which includes the steps of soaking the hides in a bath containing paraldehyde, drying the skins, rehydrating the hides and finally tanning the hides.

4. A process for treating hides to obtain leather therefrom wh'ch includes the steps of soaking the hides in a bath containing about 0.1% to 10% of paraldehyde based on the wet weight of the hides.

5. A process for treating hides to obtain leather therefrom which includes the steps of soaking the hides in a bath containing paraldehyde until the hides are plumped, and then adding a tanning agent to said bath to convert the tissues of said hides into tough, imputrescible substances.

6. A process for treating hides to obtain leather therefrom which includes the steps of soaking the hides in a bath containing about 0.1,% to 10% of paraldehyde based on the wet weight of the hides until the hides are plumped, and then adding a tanning agent to said bath to cenvert the tissues of said hides into tough, imputrescible substances.

7. A process for treating hides preliminary to tanning operations which comprises agitating the hides in an aqueous bath containing about 3% of paraldehyde, based on the wet weight of the hides until the hides are plumped and swelled.

8. A process for treating hides preliminary to tanning operations which comprises agitating the hides for about one hour in an aqueous bath containing about 3% of paraldehyde, based on the wet weight of the hides.

9. A process for treating hides to obtain leather therefrom which includes the steps of soaking the hides in a bath containing about 0.1% to 10% of paraldol based on the wet weight of the hides.

10. A process for treating hides to obtain leather therefrom which includes the steps of soaking the hides in a bath containing paraldol until the hides are plumped, and then adding a tanning agent to said bath to convert the tissues of said hides into tough, imputrescible substances.

11. A process for treating hides to obtain leather therefrom which includes the steps of soaking the hides in a bath containing about 0.1% to 10% of paraldol based on the wet weight of the hides until the hides are plumped, and then adding a tanning agent to said bath to convert the tissues of said hides into tough, imputrescible substances.

12. A process for treating hides preliminary to tanning operations which comprises agitating the hides in an aqueous bath containing about 3% of paraldol, based on the wet weight of the hides until the hides are plumped and swelled.

13. A process for treating hides preliminary to tanning operations which comprises agitating the hides for about one hour in an aqueous bath containing about 3% of paraldol, based on the wet weight of the hides.

HERBERT C. REED.