CS201737B1 - Process for treatment of grain layer - Google Patents

Description

Method of finishing the front layer of the skin

The present invention relates to a method of treating the skin layer, in particular pork, in the manufacture of leather with a nubuck surface, by heat treatment prior to decalcifying the skin.

The proportion of upper leather, especially pork β uncorrected to others, is currently relatively small and accounts for an average of 10 to 40% of total uni production. The remaining 60 to 90% are cast-corrected leathers, including hair materials. A number of defects, ranging from parasite defects, to mechanical damage resulting from contraction and to biological defects after storage, have a negative effect on the attempt to increase the proportion of facing uncorrected materials. On the other hand, the popularity and long-lasting zooming of pile leather, especially from pork, whether in footwear or galserna production, constantly forces manufacturers to improve and modify the technological processes of their production. AJ in footwear production is increasing the proportion of pork hair materials, which have good properties and are suitable especially for walking shoes.

Of the methods used to date to achieve a nubuck surface of leather, dry grinding of the cheek of the skin is the most widely used. The major drawbacks of this method are high labor, length and energy consumption. A known package is the heat treatment of the casting at temperatures ranging from 80 to 250 ° C for 0.01 to 5 seconds in the tanning stage. However, the effect of heat treatment in this way after leaching is reduced, thereby reducing the field of application

201 737

201 737 limits this period to pre-leaching operations, by thermally treating the skin after descaling and forming a solid layer of denatured proteins on the surface, which prevents the desired hair surface effect from being achieved. With the elongation of the Sas within the above interval, it can increase the stiffness of the finished leather. In terms of energy consumption, it is preferable to use heating contact elements for this epAeob. These, however, are contaminated by deneturated residues of the protein, that Slm is associated with reduced heat transfer and the need to read the device. Not ensuring perfect contact of the heating elements with the skin surface is necessary to completely remove the statins, which in operations precludes chemical, machinery, labor, and hence related elongation of the technological bowl.

The above disadvantages are overcome by the heat treatment treatment of the casting layer before decalcifying the skin according to the invention, the essence of which is that the skins move against a round heat curtain at a temperature of 400 to 1500 ° C at a speed of 0.01 to 0.09 m / s.

Within this temperature range, the denaturation of the proteins on the surface of the skin layer of the skin is thermally shocked, allowing the treatment process to be directed so as not to denature the proteins in the mass, which does not happen at lower temperatures.

The technical effect of the invention is manifested by increasing the productivity of the casting skin treatment, saving the energy required to perform the treatment, and achieving a smoother, more even hair surface with a so-called "stinging effect".

The treatment of the casting layer of leather according to the invention is illustrated by the following examples.

Example 1

After soaking, defatting and shaving, the skins are placed on a conveyor belt moving at a speed of 0.03 m / s. The conveyor belt passes under the burner, which is arranged throughout the spruce of the treated leather and forms an avalanche screen. The skin is turned towards the thermal pellet by its casting, with the surface temperature of the skin reaching 450 ° C. Baled skins pass under a water shower where aa has cooled. The process continues with leaching and the usual technological process, excluding operations of drying, ironing and grinding.

Example 2

After wetting, defatting, stripping, air-calcium leaching and subsequent washing, the skins are split and deposited on a conveyor belt moving at a speed of 0.08 m / s. The conveyor belt passes under a burner formed over the entire spruce of the treated leather. The flame temperature on the skin surface is 1300 ° C. After passing through the skin under the burner ea, these are cooled with a water spray, taken from the conveyor belt, washed in running water for 10 minutes with warming to 30 ° C, decalcified aa and after 3 further raising the temperature of the descaling bath to 38 ° C . Balej ea continues its current technological poet3

201 737 pe except for the operations listed in example 1.

Heat sources for said temperature range may be e.g. a breed of flammable gases, infrared heaters, or overheated steam. By a suitable combination of the temperature and the skin of heat on the cheek of the skin, it is possible to achieve a different depth of destruction and thus the desired type of hair surface. In comparison with β classical technology of nubuck leather production by grinding, at least four working operations are saved, while saving up to 1/3 of the energy currently consumed in the wet part and pretreatment. Compared with the use of lower temperature contact heating elements, one wet operation is saved and the quality of the hair surface of the leather is improved.

Claims (1)

OBJECT OF THE INVENTION The method of treating the facing layer of hides by heat treatment in the pre-descaling phase of the skin treatment phase is characterized in that the skin moves under a continuous heat curtain at a pour temperature of 400 to 1500 ° C at a rate of 0.01 to 0.09 m / e.