GB2236111A

GB2236111A - Increasing the area yield of chrome tanned leathers

Info

Publication number: GB2236111A
Application number: GB8921525A
Authority: GB
Inventors: Laszlo Horvath; Gyoergy Horvath
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-09-22
Filing date: 1989-09-22
Publication date: 1991-03-27
Also published as: GB8921525D0

Abstract

Leather in the wet blue state having excellent pliability is treated by means of two simultaneous power effects: -stretching with tongs and -rolling on a level surface. The area yield can be increased up to 10%, and at the same time the thickness of the unrolled wet blue surface will decrease proportionately. The quality of the finished leather remains unchanged compared to that of the unrolled finished leather.

Description

Increase of the area yield of chrome tanned upper leathers by rolling on a level surface bench Backqrounds Let's consider the state of the hides after soaking as a reference base, lets' take it 100% .

On the base of the average figures from the literature the area of the pelts after liming covers 85-86%, in wet blue state 8285%, after carving 88-92%, in posttannage state 80-82%, in crust state 84-86%, while in finished leather 82-83% .

The area yield is of vital importance in the economic life of-tanneries.

Our new method increasing the area yield We have originated our method from the conception that the wet blue state has been the most suitable state to promote a favourable formation of the connections between the collagen fibres in the shrivelled tanned skin by an indulgent process.

Following this process the wet blue skins will be submitted to a further wet process in which they are granted a new possibility that their collagen fibres shall themselves rearrange against the tolerant settlement resulted by our method.

During our experiments we have experienced that this rearrangement will be proceeded in the phase of posttannage and the quality of the finished leather won't be demaged while increasing the area yield.up to 10C;6.

Our method do- not exclude the applications of the previous procedures for increasing the area yields;in the contrary it is compatible with them.

The base of our method is the observation that following the mineral tannage the ability of the wet blue skins to be worked up in fresh warm state is excellent, this is why relatively small power effects applied suitably will cause big increases in area yields.

Without preliminary dewatering - the fresh whole wet blue skins must be laid one by one onto a strong level surface bench. On two opposite sides '. the wet blue skin shall be held with tongs every 2 to 3 inches apart.Now the tongs will be flexed so as the streching power will be 50-60 lb/inch. Following this a hydraulic press roller will be led onto the surface of the wet blue skin and start rolling from tongs to tongs at a linepressure of 40 701b/inch. The roller shall travel forward and back till the adequate increase in the area has been completed. It is favourable that the first direction of the movement of the roller shall be perpendicular to the line of the spinal column. Now the tongs must be unfastened and the edges of the skin shall be rolled cautiously so as to avoid wrinklings.

Then the skin will be turned away at right angles to the first position; the tongs will- the tongs be fastened to the edges of the skin and the rolling shall go on till the required 1096 increase in area yield has been reached. In connection with this requirement it must be noted that one third of the area increasing in wet blue state \nll be ceased while processing up to finished leather (15%it 10%) The liquid from the wet blue skin will be pressed out during the rolling process and the liquid must flow off the bench.

After rolling the wet blue skin seems to be dry and stiff, but this state will not cross the further steps of the process to be carried out.

The rolled wet blue skins must be let to repose for five hours.

This way the quality of the finished leather remains unchanged, while the area yield can be increased 10% Summary We have carried out. our experiments in wet blue state having excellent pliability, by means of two simultaneous power effects: -stretching with tongs and -rolling on a level surface.

Applying our method the area yield can be increased up to 10%, at the same time the thicness of the unrolled wet blue skin will decrease proportionately.

The quality of the finished leather with our method will remain unchanged to that of the unrolled finished leather.

Our method needn't be conformed to a decided machinary solution.

Claims

"CLAIM'

By using the Laszlo & Gyorgy Horvath's process the crone tanned upper leathers will increase in size between 2% - 14% without loss of quality to the leathers.