DE906007C - Process for the pretreatment of keratin with an oxidizing agent - Google Patents

Description

(The invention relates to the production or pretreatment of keratin Elrfindiung made keratin can be used for various Purposes.

Ice cream have already been suggested for making artificial threads made of keratinous material, as found in wool waste and animal; Hlaaren, Horns and hooves finds, made. Such suggestions usually consist of the kferatin

ίο after suitable pretreatment in a liquid, such as cuprammonium solution, aqueous solutions of urea with or without reducing agent or aqueous ammonia, caustic soda or sodium sulfide solution to dissolve or disperse and the solution or dispersion in a precipitation bath, generally an acidic bath, which one or more Salts contains ¹ to spin. E ¹ S has already been proposed to pretreat the keratin-containing material with oxidizing agents. Thus, P. Alexander, RF Hudson and M. Fox in "The Biochemical Journal", Vol. 46, No. 1, 1950, pp. 27 to 32, propose to pretreat the keratin with oxidizing agents including peracetic acid, the keratin thus treated is soluble in aqueous sodium hydroxide, ammonium hydroxide and urea solutions. It is believed that the action of peracetic acid is to oxidize and break the cystine bond in the keratin so that the oxidized product becomes soluble or dispersible in alkali. However, the use of peracetic acid as an oxidizing agent is undesirable in large-scale operations. The acid itself is

caustic and! harmful to the worker, and moreover is the production of acid from acetic anhydride and hydrogen peroxide dangerous as the mixture can explode.

The invention aims at an improved oxidative pretreatment of keratin mainly for the production of regenerated keratin threads.

{Elrfindüngs according to a method for oxidizing Pretreatment of keratin in it, the ίο keratin the action of hydrogen peroxide in To expose the present of the iron vitriol and an acid. The preferred acid is sulfuric acid, but also other acids such as phosphoric acid and Acetic acid, can be used. DSe used i Quantities of hydrous vitriol and sulfuric acid can be 2 to 20% by weight of the Weight of the keratin. Preferably one uses 8 to ι ο%> , Elisenvitriol, calculated on the weight of the keratin. The amount used ao acid should be sufficient to dissolve the iEÜsenivitriol to keep. Too ig per liter of iron vitriol is usually needed about ig per liter Sulfuric acid.

The keratin pretreated according to the invention is easily soluble in dilute alkali and can therefore serve to produce keratin solution. The keratin becomes the action of hydrogen peroxide in the presence of Elisenvitriol and: subjected to an acid and the oxidized keratin in dissolved in an aqueous alkaline solution. The so The solutions obtained can be used directly as a spinning solution in the production of synthetic threads will. They can also serve as sizes and dispersants.

, A process for making precipitated Keratin threads using the pretreatment method according to the invention consists in that Keratin in Giegenwart from 'iron vitriol and an acid to the effect of hydrogen peroxide subject the oxidized keratin in aqueous alkaline solution, such as aqueous ammonia or aqueous caustic soda solution, to dissolve and the resulting solution to be spun in an aqueous precipitation bath, which contains one or more metal salts known to coagulate proteins. Suitable salts are sodium sulfate, magnesium sulfate and aluminum sulfate. It can mixtures of such salts can also be used. The bath preferably has a py value 5 and 9.

'The artificial protein threads obtained by applying the invention are made in the usual way stretched, hardened and made insoluble.

The stretching should usually be at least 50% be. But it is preferably higher, e.g. B. 100 to 300%. The stretching can be in the air or be carried out in the presence of a coagulation bath, which does not contain any or essentially contains no Hartunigsmittel.

The hardening baths can be those usually proposed for this purpose with casein threads, e.g. B. Aqueous formaldehyde alone or preferably in combination with one or more metal salts · ™, such as sodium sulfate, magnesium sulfate, aluminum sulfate, Calcium chloride, zinc chloride, basic chromium sulfate and zirconyl sulfate.

After curing, the threads are preferred a treatment to insolubilize, as it is usually applied to protein threads, subject !. The preferred treatment for insolubilization is the use of formaldehyde and sodium bisulfate, as in the 822,000 patent described.

The hardened threads can then be stretched further and then treated in a hardening bath without their being able to contract further

The precipitated keratin threads obtained using the invention generally have Alpha as determined by X-ray analysis and have a wool-like elasticity.

B e i s ρ i e 1 ι

ioo'g wool waste was stirred at 20 ⁰ with 1500'ecm 100 volumprozentigem hydrogen peroxide containing 8 g of ferrous sulphate (Fe'S O ₄ · 7 H ₂ O) and 9 g of sulfuric acid per liter. The temperature was maintained by external cooling at 20 · ⁰ until the reaction subsided. The mixture was allowed to stand for 16 hours at 20 ^0th The fibers were separated and washed with water until free from the treatment bath. The fibrous product was then stirred with 3 liters of 75% aqueous ammonium hydroxide for 4 hours. The liquid was filtered off from a tiny insoluble residue and clarified by centrifugation in a gravitational field of 100 X g. The clear liquid was then stirred and sufficient 2 N sulfuric acid was added to bring the _pH value to 4, so that a white cheesy solid precipitated out, which was filtered through eini cotton fabric and was freed by pressing from the external liquid. ¹ The wet precipitate was then quenched by addition of sufficient, concentrated ammonia (sp. Weight 0.88) dissolved again, and the p _H to 9 -tWert increased.

The viscous solution obtained was then centrifuged in order to free it from air and other particles and then spun into an aqueous solution which contained 4501 g of crystalline magnesium sulfate (Mg ¹ SO ₄ · 7iHl> 0) and 150 g of anhydrous sodium sulfate per liter, the p _H -i value of solution 7 was. freshly spun thread was then stretched by 200% on conical rollers with axes inclined towards one another. D ^! The lower roller turned in a solution which had the same composition as the precipitation bath.

The threads were then collected on a godet and ^{cured for 2 hours at 50 10} in a bath containing per liter 10-g of formaldehyde, 450 g of crystallized magnesium sulfate and 150 g of anhydrous sodium sulfate, and then for 2 hours in a bath of 45 ° by a further treatment made insoluble. The bath contained per liter

iog formaldehyde, 300g sodium sulfate and 400g Sulfuric acid, the threads were then placed ini water washed and dried.

Example 2

100 g of wool waste were ^{stirred at 20 0} with 600 ecm of 100 percent by volume hydrogen peroxide, which contained 2 g (ferric vitriol and 100 ecm 5 η-sulfuric acid. The mixture was stirred for 3 hours with external cooling, which kept the temperature at about 20 ⁰ Mitsdhunig was then dissolved in an equal volume of water and, after stirring, left to stand for 3 days.The solid component was separated off, dissolved and spun as in Example 1.

The procedure according to Example 1 and. 2 fireplace too are applied to rabbit hair and yields threads with tensile strength similar to that of the Examples 1 and 2 made from regenerated wool.

Claims (2)

Patent claims: ι. Process for the pretreatment of keratin with an oxidizing agent, characterized in that that the keratin in the presence of iron vitriol and an acid, preferably sulfuric acid, the action of hydrogen peroxide is subjected. 2. The method according to claim 1, characterized in that that 2 to 20 percent by weight of Elisenvitriol, calculated on the Gbwicht of the keratin, are used.