DE1669344B1 - Process for depilating skins or pelts - Google Patents

Description

1 2

When hair is removed from hides or skins, oxidation occurs after 6 to 10 hours. in the

as is well known, in addition to a complete contrast to the. Depilation with propanol dissolve the

removal of the hair, the nakedness with simultaneous skin-hair in the alkaline medium not completely open. Want

attacking exposure as little as possible. To do this you have to completely remove the hair here In addition to the classic liming, the amount of sodium chlorite was increased to 10 to 12%.

drive with lime and sulphide, which some process ends. The same effect as described above can be achieved

technical and wastewater difficulties also due to isopropanol or technical mixtures of

brings with it, more recently achieve various other propanols or butanols.

Process introduced that z. B. with caustic soda and the tests were also carried out on calfskin dimethylamine (JALCA, 1963, pp. 254-270) or with io leads and showed the same results.

Chlorine dioxide or chlorites in an acidic medium (Das..

Leder 15 [1964], No. 5, pp. 119 to 121, and German B e ι s ρ ι e 1 2

Auslegeschrift 1 230 517) work. 3.5 kg of a softened and fleshed beef skin

It is also known for the dehairing per compounds, were mixed with 50 to 75% (= 2.63 1) about a / 5.0 ° _o by weight namely, inorganic peroxides, including water 15 aqueous peracetic acid solution and 10 to 30% propaganda

substance peroxide, inorganic or organic peracids nol milled. The hair is in contrast to one

or persalts or mixtures of per compounds. Oxidation without propanol after 4 to 6 hours

and alkali chlorites, or alkali and alkaline earth boron (otherwise 10 to 12 hours) attacked so far that they

nate to use. dissolve in alkaline medium.

It has now been found that the dehairing 20 The pH value during dehairing can be 2 to

tion process with amines, chlorine dioxide or chlorine 5.5.

th, per compounds alone or in mixture with The basic hair and hair roots are opposite

Chlorites or with alkali or alkaline earth boranates of a pure peracetic acid hair removal better φ

The depilation time can be shortened significantly, and can be reached and left by an alkali treatment although with thorough removal of the basic hairs and 25 easily remove.

Hair roots, d. H. Obtaining a larger percentage. .

Set of aniline leather and with a smaller amount of Ent- Example 3

Hair removal chemicals, if 1.5 kg of softened and fleshed beef skin was used for the above-mentioned treatment

drive depilatory liquors are used, which are in a fulling drum with 3% Na ₃ O ₂ and 4% Na ₂ SO ₄ in

Propanol, isopropanol or their technical 30 30% hotte treated. The fleet sat together

mix or butanols or their technical mixtures from (based on the weight of the skin) 20% water

as hydrotropes in quantities to the liquor = 300 ml and 10% propanol or isopropanol

Contains added water from 1: 1 to 1:10. = 150 ml.

As is well known, hydrotropic substances are used for the skin is in this mixture with 2 to 6 um-

Solubilization of water-insoluble compounds drummed 35 times per minute. After 20 to 30 minutes

fertilize. The hydrotropic substances are said to be cohesive, the hair is completely dissolved, and the skin is

sion forces are bound to the substance to be dissolved. blank. The skin is opened up at the same time, where-

In the present case, hydro- swelling is likely to occur, which is caused by the sodium

phobic bonds in the keratin broken (see e.g. the amount of peroxide, the amount of sodium sulfate and the water

R ö m ρ ρ, Chemielexikon, Part II, 6th edition, p. 2838). 40 water volume can be controlled. Larger proportions of

A further advantage of the process according to the invention, Na ₂ O ₂ or a reduction in the Na ₂ SO ₄ proportion, is that the duration of the depilation is greater than the swelling. The same amount of depilatory chemicals has the same effect as an increased addition of water. After the amount of said hydrotropic sub- added after depilation, the skins can, if desired, be directly neutral. As a result, there is now a possibility of pickling, pickling, picking and tanning if necessary. ™ give the hair removal process fully automatically
control and regulate. B e 1 s ρ 1 e 1 4

. -I ₁ 1.35 kg beef skin red and white, softened and fleshed,

example are treated with in a fulling barrel

1.5 kg of a softened and fleshed beef skin 5 ° 3 «· / Na O '

were with 20% water (300 ml), 10% propanol as ■ 5 J, ⁰ ρ _Γ ορ2ά _ο1

hydrotropic substance (150 ml) and 6% of a sodium 12 "/ water '

chlorite solution, which contains 300 g of _{100% NaClO 2} per liter of ^{/ o Wclbbcr}

holds, in a fulling barrel at 2 to 8 revolutions per The hair is completely dissolved after 30 minutes.

Minute treated. The depilatory liquor was 55. The pelts are swollen. If you give swelling inhibit-

Formic acid and sulfuric acid mende to pH. Means such as B. Na ₃ SO ₄ or NaCl, see above

acidified from 3.0 to 3.5. The swelling is reduced after just 3 hours,

the hair is very heavily oxidized and the skin is damaged.

bleaches. After 6 to 10 hours the hair is ready for example 5

oxidizes that they dissolve in alkaline solution. ^ß o 2 half cowhides, soft weight 23.5 kg, were

As a counter-attempt, depilation was carried out with 1.35 kg in a fulling barrel

the same bovine skin, but without propanol, through- ^ 0 / natrinminrocvri

guided. The skin was in 30% water (= 405 ml) U * sodium sulfate '

drummed with 6% sodium chlorite solution as above. The 13 ° / ° water '

pH was again with formic and sulfuric acid 6 ₅ ° propanol, isopropanol or a technical

set to 3.0 to 3.5. After 3 hours the _specific ^P _{n mixe} £ ^ _{n propanols}
Hair attacked, but significantly less oxidized

than with depilation with propanol. This is shown treated. The skins swell only moderately, and after 2

Claims (1)

3 4 up to 3 hours the hair is completely removed. The skins example 7
can then, if desired, be neutralized, pickled, peeled and tanned directly. 1.5 kg of a softened and fleshed beef skin As a counter-attempt, depilation without pro was in a fulling barrel with 30%, based on the panole made with 30% water. The hair treated 5 soft weight, a solution that existed are attacked after 3 hours, but not open solved. For complete depilation, Reac- -t ^ q ₀ / v> _IOOano \ (- 150 ml ") tion times of up to 15 hours are necessary. ₂₀ £ _o f ^ ₁ J _{1 wiiß} \ _{solution (= 3 300m} i), in which It is also possible, without the _{addition of sodium sulfate, to add 200} ^ of _a ⁵ _{30 per cent} sodium content to each liter. ^work · ¹⁰ chlorite solution and 100 g sodium persulfate Example 6 contained. 15.8 kg of a soaked and meatless beef skin was 2 to 3 hours in this solution skin were drummed with. The hair was damaged, the skin 3 ° / NaOH ¹⁵ frl ^e i ^cnt 3 ° / ° Na So '^ * Sodium bicarbonate or sodium carbonate las- 1.5% D ^a imethylaminsulfat or ^let L ^{s} ch} * ^ie oxidized hair completely dissolve. 2% dimethylamine (as a 40% solution) ₊ These examples show the advantages mentioned at the beginning parts, namely the much shorter depilatory in 80 to 100% water and 20 to 30% propanol, iso-20 duration, the use of considerably smaller amounts of propanol or a technical mixture of propanol and depilatory chemicals and the better removal in a drum. The hair is from the basic hair and hair roots,
completely removed after 5 to 8 hours. The depilation can also be carried out in such a way that the following recipe claims: door is used: 25 procedures for dehairing hides or On the soft weight of the skin are used: skins with amines, chlorine dioxide or chlorites, 2 5 ° / NaOH per compounds alone or in a mixture with l'o ^o / ° Na So 'chlorites, or with alkali or alkaline earth borana 0 * 3 to 01 ⁰ / NaHS ^ten 'characterized in that i; 0% dimet vinyl sulfate, ³ °! ^lche depilatory liquors are used that 50% liquor, consisting of 15% propanol or propanol isopropanol or their technical Mixture of isomers and 35% water. ^m ! ^sc * ^eo _t ^of _u butanols or their technical Ge mix as a hydrotrope stone in quantities to the The hair removal is completed after 4 to 6 hours - liquor water of 1: 1 to 1:10 added and removed. sen. 35 hold.