DE1494740C3 - Process for the production of collagen fibers from waste leather - Google Patents

Description

The invention relates to a method for the production of collagen fibers from leather waste as Base products for leather fiber materials, both woven and non-woven. Such leather fiber materials, made from collagen fibers have, compared to those made from synthetic fibers, better properties in terms of moisture absorption, thermal conductivity and dyeability. Leather fiber materials made from collagen fibers are therefore used on a large scale.

It is known to convert collagen fibers from leather waste by means of a chemical treatment with hydrazine to win. However, this method is expensive and associated with a reduction in the quality of the fibers.

The main object of the invention is a method for obtaining collagen fibers for manufacture of leather fiber materials that are easy to use and produce a high yield of higher quality Fibers.

In particular, the longest but thinnest collagen fibers are intended with the method according to the invention are obtained from the leather waste. According to the invention, the stated aim is achieved by that the leather raw material is soaked in water, then freed from undesirable components and with regard to the tannin content is adjusted so that the thermal contraction of the KoI-ply raw material above 80 ° C is that the material is dewatered by an oil additive that the dehydrated substance is then subjected to an impact treatment and that finally the treated in this way Fiber substance for obtaining the fibers

ίο is wrapped tightly around a rotating roller and is brought together with a scratch pad.

In detail, the rawhide material is immersed in warm water during the first process step (50 to 60 ° C) soaked with a nonionic surfactant and then for -30 drummed for up to 60 minutes.

The treated soft leather is then put back into warm water to remove it contained salt and solvent substances.

ao trigger. Excess tannins must be removed in order to obtain a corresponding Tanning agent content, for example content of chromium salts, to adjust, which is necessary to to obtain a thermal contraction of the collagen above 80 ° C. This tannin removal is necessary, because a top section of tannin, especially chromium salts, destroy the fiber structure, in particular, however, can also affect the softness.

In chrome tanning, the thermal contraction is maintained at 2 to 3% chromium oxide (Cr ₂ O ₃ ), based on the collagen.

As an agent for dechroming, a solution with organic acids is used, for example Oxalic acid, tartaric acid and citric acid.

In the case of vegetable tanned leather, the tanning agent content is adjusted to 35 ° C by the leather is placed in a solution of caustic soda, acetone or methanol.

Subsequent to the adjustment of the tannin content, the leather is immersed in an alkaline solution of caustic soda, sodium carbonate or sodium bicarbonate put after washing it in water is. .

The desired degree of alkalinity should be similar to sodium bicarbonate in terms of the temperature for thermal contraction, the degree of swelling and the acidity of sulfuric acid.
When it is desired to obtain fibers of a certain length and thickness, barium hydroxide will give the best results. The temperature of the solutions and the pH value for chrome leather was 40 to 45 ° C at pH 5.2 to 6.4. This resulted in a uniformly neutralized leather.

SS After the above-mentioned alkaline treatment, the leather is turned into an oil percent at normal temperature Urea solution placed. This urea treatment leads to a loosening of the collagen fibers, because the hydrogen bonds between the collagen fibers are largely broken. The desired thin and long fibers can then be obtained by dissolving the fiber structure. In the second stage of the procedure, a treatment in one is used in preparation for the stroke treatment Sulphonated oil emulsion carried out with 1% by weight of oil based on the raw material. The leather is then drained until a water content of 35 to 50% is established.

This conditioning is one of the crucial steps in protecting the fibers against shortening in the subsequent stroke treatment.

The amount and type of sulfonated oil added can, however, depend on the type of to Winning fibers can be chosen. However, it is desirable to use oils with a higher sulfuric acid content to be used, such as olive oil, neat foot oil and the like.

The above-mentioned water content of 35 to 50 ⁰ Zo is the preferred water content for the subsequent beating treatment, by which the individual fibers are dissolved, so that the fiber mat can easily be dissolved.

As stated in this process step, the pretreated fibers are subjected to a mechanical one Exposed to impact or stamping treatment. Then the fibers are placed on a rotating Wooden roller are attached, od in a card. Like. Won.

Embodiment:

ao

7 kg of chrome split leather were in warm water with 50 ° C and an addition of 1% non-ionic surface-active agent based on the weight of the treated substance and applied for 5 hours as left in the water. The material thus treated was then left in the drum for one hour fulled. The milled leathers were then placed in warm water at 50 ° C. for 2 hours to dissolve out the remaining salt and other undesirable components.

The chrome leather was then treated in a 0.1% oxalic acid solution, based on the weight of the leather in a drum, for 30 minutes. After the chromium content had been adjusted to 2 to 2.5% chromium oxide (Cr ₂ O ₃ ) and washed in water for 20 minutes, the leather with its tannin content was in a 0.2% strength, based on the Leather weight, sodium bicarbonate solution at 40 ° C in the drum for one hour. After the pH had been adjusted to 5.2 to 6.4, the leather was carefully washed, treated for one hour in a 0.1%, based on the weight of the leather, urea solution in the drum and then washed again.

The leather was then sulfonated in an emulsion with 2%>, based on the leather weight! olive oil treated. The material was then dewatered in the centrifuge to a water content of 40%.

The semi-dry substance was then treated in a tamper for 30 minutes and then wrapped tightly around a wooden roller (25 cm wide and 15 cm diameter) and with a Scratch covering brought together at a rotational speed of 1300 rpm. Here were 3 kg Collagen fibers 0.05 mm thick and 40 to 60 mm long were obtained.

Claims (5)

Patent claims: 1. A method for obtaining collagen fibers from leather waste, characterized in that that the leather raw material is soaked in the water, then undesirable Components freed and adjusted with regard to the tannin content so that the thermal contraction of the collagen raw material is above 80 ° C that the material is dehydrated by an oil additive that the dehydrated substance is then subjected to an impact treatment is subjected and that finally the fiber substance treated in this way for recovery the fibers are wrapped tightly around a rotating roller and brought together with a scratching pad will. 2. The method according to claim 1, characterized in that that the leather raw material for soaking in warm water with 50 to 60 ° C and an additive of a nonionic surfactant and then placed in a Drum is milled. 3. The method according to claim 1, characterized in that to adjust the content of a chrome tanning agent, the material is brought into a solution of an organic acid. 4. The method according to claim 1, characterized in that that to adjust the content of the leather in a vegetable tanned leather, the leather in a solution with caustic soda, Acetone or methanol is treated. 5. The method according to claim 1, characterized in that the drying in an emulsion Carried out with 1 percent by weight of sulfonated oil up to a water content of 35 to 50% will.