The method of tanning leather

 

(57) Abstract:

The invention relates to chemical treatment of skins, namely the method of tanning leather using polymeric tanning substances and mineral tanning agent. The hide is consistently treated in an aqueous medium at a temperature of 10-70oPolymer tanning substance - N-takanohana with a degree of takanohana 20-90% and a molecular mass of 1103-100103and mineral tanning agent the chromium salts. The processing of the hide implement 0,5-5,0% aqueous solution of N-takanohana at pH of 1.5 to 6.5 for 4-24 h in the amount of 1.0-10% by weight of the hide, and then salts of chromium at a flow rate of 0.5-2.0% by weight of the hide, in terms of oxide of chromium (III). The method allows to increase the quality of produced of leather, the efficiency of the process by reducing the cost and complexity of processing and to reduce the consumption of tanning salts of chromium. 2 C.p. f-crystals.

The present invention relates to a method of chemical treatment of skins, namely the method of tanning leather using polymeric tanning substances and mineral tanning agent, and can be used in the leather industry in the production of leather for various purposes.

In a number of patents described ispolnitelnogo, amine and hydrocarbon character and mineral tanning agent.

For example, there is a method of tanning leather after chrome tanning sulfisomidine the oligomers obtained by copolymerization of acrylic acid, Acrylonitrile and acrylamide in aqueous Hydrosulphite solution of sodium /CH 646731 A5, CIBA-GEIGY AG, 14.12.84, C 14 C 3/22/.

Described tanning compositions based on graft copolymers of acrylic and methacrylic acids or methacrolein with glucose, maltose, dextrose, starch and various derivatives of cellulose /US 5425784 A, BASF AG, 20.01.95, C 14 C 3/22/.

There is a method of retanning leather using polymeric tanning agent based on unsaturated carboxylic acids, the molecules which include the amino and carboxyl groups, and carboxyl groups than amino groups /DE 3201226 A1, BASF AG, 28.07.83, C 14 C 3/22/.

There is also known a method of processing pickling solution of oligomers of acrylic acid with molecular weight of 2000 - 2200 with subsequent mineral tanning /SU 1444348 A1, research Institute of leather and footwear industry, 15.12.88, C 14 C 1/08/.

The closest known solution of an analogous problem is the method of tanning leather by treatment of the hide polymer tanning agent and mineral d is sieciowej acid and unsaturated C3-C5-carboxylic acids, for example maleic, crotonic, or takenaway. The processing of the hide polymer tanning substance is carried out in aqueous medium at a temperature of 10 to 70oC and pH 4 to 8. As a mineral tanning agent use salts of chromium, aluminum or zirconium. The method allows for a consistent treatment of the hide polymer tanning agent and mineral tanning agent, and the processing of the hide first mineral tanning agent or introduction simultaneously with the polymer tanning agent.

The disadvantages of this method include the difficulty of obtaining polymeric tanning substances by polymerization of the monomers at a temperature of 80 - 150oC in the presence of a catalyst, which cannot be done in terms of the leather industry.

The present invention is to remedy these disadvantages, improving the quality produced by the skin, improving process efficiency by reducing the cost and complexity of processing, reduction of consumption tanning salts of chromium.

To solve the problem proposed by the present method of tanning leather, comprising the sequential processing of the hide in water at a temperature of 10 - is milirovanie 20 - 90% and molecular weight of 1 to 103- 100 103and mineral tanning agent the chromium salts. The processing of the hide implement 0,5 - 5,0% aqueous solution of N-takanohana in the amount of 1.0 to 10.0% by weight of the hide at a pH of 1.5 to 6.5 for 4 to 24 h Treatment with salts of chromium are at a flow rate of tanning agent 0.5 to 2.0% by weight of the hide, in terms of chromium oxide /III/.

Use as polymeric tanning substances N-takanohana - natural aminopolysaccharide coated chitosan, acylated taconova anhydride, allows to obtain samples of leather, which has a higher mechanical strength and okrashivaemoy, bacteriostatic and water-repellent effect, improved organoleptic properties.

An important feature of the proposed method of tanning is the ease of preparation of a solution of N-takanohana of chitosan and faconnage anhydride, which allows to obtain polymeric tanning agent in the required amount directly in terms of the leather industry. Unprocessed chitosan components remain in minimum quantities and because of its Biodegradability exert almost no effect on the environment.

Istniejacym chemical production. Acylation of chitosan any molecular weight taconova anhydride smoothly flows for 0.5 - 1.0 hours in water at room temperature and leads to N-takanohana with a given degree of substitution depending on the ratio of initial reagents.

According to the invention, during the processing of a pickling solution of N-takanohana with the subsequent action of the salts of chromium in quantities several times smaller than the standard chrome tannage, diffusion occurs takanohashi molecules in the internal salt of the dermis, pinning them there by complexation with collagen chains with subsequent structuring by stitching chicoasen chains oxygen by allyl provisions facinoli groups. The addition of small amounts of chromium salts leads to the formation of complexes of hydrated ions of Cr3+as with protein and chitosan chains than layers of the dermis are structured separately. The presence of chitosan molecules provides vysokogermetichnoe properties of the produced material.

Get samples of skin temperature welding 90 - 115oC and shrinkage 0 - 5%.

The following examples illustrate the present invention.

oC 2.25 g of taconova anhydride, stirred for further 20 min and get a 5% solution of N-takanohana with a degree of takanohana 20%.

Sample obezzolennogo, marcenaro naikeleyaga pickling weight of 30 g of raw cattle treated in the drum 60 ml of the obtained solution /10% N-takanohana by weight of the hide/ for 4 h at room temperature at a pH of 1.5. The sample was then subjected to the action of 60 ml of a 1.5% aqueous solution of chromium sulfate /1.0% tanning agent by weight of the hide, in terms of Cr2O3/ for 8 h followed by treatment with 1% solution of sodium bicarbonate for 2 hours, the resulting material has a temperature of welding 90oC and shrinkage 0%.

Example 2. To a solution of 1 g of chitosan /MWwithin 5 to 103- 30 103/ 100 ml of 1% acetic acid was added for 20 min at 20oC portions with stirring 0.85 grams of taconova anhydride, stirred for further 20 min, dilute with water to volume of 320 ml and receive a 0.5% solution of N-takanohana with a degree of substitution of 90%.

Sample obezzolennogo, marcenaro naikeleyaga hide from raw sheepskin weighing 30 g is treated in the drum 60 ml of the obtained solution /1.0% of N-takanohana by weight of the hide/ ssy pickling in terms of Cr2O3/ for 6 h followed by treatment with 1% solution of sodium bicarbonate for 2 hours, the resulting material has a temperature welding 105oC and shrinkage 4%.

Example 3. To a solution of 5 g of chitosan /MWwithin 1 to 103- 10 of 103/ in 200 ml of 2% acetic acid was added for 20 min at 20oC portions with stirring 2.5 g of taconova anhydride, stirred for further 20 minutes, dilute with water to volume of 350 ml and receive a 2% solution of N-takanohana with a degree of substitution of 60%.

Sample obezzolennogo, marcenaro naikeleyaga pickling pork raw material weighing 30 g is treated in the drum 60 ml of the obtained solution /4.0 percent N-takanohana by weight of the hide/ for 8 h at pH 3.5. Next, the sample is subjected to the action of 60 ml of 3% aqueous solution of chromium sulfate /2,0% tanning agent by weight of the hide, in terms of Cr2O3/ for 8 h followed by treatment with 1% solution of sodium bicarbonate for 2 hours, the resulting material has a temperature welding 115oC and shrinkage 3%.

1. The method of tanning leather, comprising the sequential processing of the hide in water at a temperature of 10-70oPolymer tanning agent and mineral tanning agent the chromium salts, of which availibale 20 - 90% and molecular weight of 1 to 103- 100 103.

2. The method according to p. 1, characterized in that the processing of the hide implement 0,5 - 5,0% aqueous solution of N-takanohana in the amount of 1.0 - 10% by weight of the hide at a pH of 1.5 to 6.5 for 4 to 24 hours

3. The method according to p. 1, characterized in that the treatment with salts of chromium are at a flow rate of tanning agent 0.5 to 2.0% by weight of the hide, in terms of oxide of chromium (III).

 

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The invention relates to chemical treatment of skins, and tanned hides, and is intended for use in the leather industry for tanning skins from Astrakhan, sheepskin, goat and other skins

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SUBSTANCE: claimed method includes diphenolepropane sulgation and condensation with formaldehyde followed by acidifying with sulfuric acid. Formed product is dispersed in lignosulfates containing 0.5-1.5 % of aluminum sulfate as calculated to aluminum oxide.

EFFECT: syntans with stable content of tanned materials: environmentally friendly and economical process.

1 ex

FIELD: chemistry of polymers, leather industry, chemical technology.

SUBSTANCE: invention relates to a method for preparing polymeric products that are used in processes for dressing leather or fur, in treatment and disinfection of natural and sewage waters. Method for preparing polymeric products involves the hydroxymethylation reaction of polyhexamethylene guanidine chloride with formaldehyde and arylation reaction of prepared product with aromatic compound comprising o-amino- or o-hydroxy-groups. The hydroxymethylation reaction is carried out in the presence of acetic acid or formic acid up to formation of trimethylol derivative of polyhexamethylene guanidine chloride. In some cases the arylation product is subjected for complex formation with transient metal salt or azo-coupling reaction with diazonium salt taken among group including sulfanilic acid, naphthionic acid, j-naphthyls, p-nitroaniline, 2,6-dichloro-4-nitroaniline. Invention provides simplifying, accelerating and enhancing the effectiveness of process in dressing leathers with derivatives of polyhexamethylene guanidine showing tanning effect, staining properties, flocculating capacity and high antibacterial activity.

EFFECT: improved preparing method.

3 cl, 1 tbl, 9 ex

FIELD: chemistry.

SUBSTANCE: invention relates to graft polymers based on polysaccharides and polypeptides. Graft polymer based on polysaccharides and polypeptides or respective derivatives thereof are obtained by free-radical polymerisation of A) a monomer selected from following, or a mixture of following monomers: (a) from 20 to 100 wt% acrylic acid or methacrylic acid, or mixture thereof, or salts thereof with an alkali metal, alkali-earth metal or ammonium, (b) from 0 to 80 wt% other monoethylenically unsaturated monomers, which can be copolymerised with monomer (a) and (c) from 0 to 5 wt% monomers containing per molecule at least 2 ethylenically unsaturated unconjugated double bonds in presence of B1) polysaccharides subjected to oxidative, hydrolytic or enzymatic decomposition, oxidised polysaccharides subjected to hydrolytic decomposition or subjected to enzymatic decomposition, or chemically modified decomposed products, chemically modified mono-, oligo-or polysaccharides, or mixtures of said compounds and B2) polypeptides subjected to hydrolytic or enzymatic decomposition and optionally chemically modified polypeptides, or mixtures of said compounds, with weight ratio A:(B1+B2) ranging from 60:40 to 1:99 and B1:B2 from 97:3 to 3:97. Also disclosed is a method of producing graft polymers, method of tanning leather, and tanned leather.

EFFECT: wider range of polymers for various types of tanning.

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FIELD: chemistry.

SUBSTANCE: method involves tanning a semi-finished product with a chrome tanning agent, neutralisation, washing, dyeing and tanning with organic tanning agents twice. The first tanning is carried out with a polymeric tanning agent, while the second is carried out with a mixture of synthetic and vegetable tanning agents. Hydrophobicising greasing, treatment with an organic acid and re-tanning with a chrome tanning agent are then carried out. Additional washing is carried out before neutralisation. Dyeing is carried out after the second tanning. Neutralisation, tanning twice and dyeing are carried out at water-to-goods ratio of 0.5-0.7. Hydrophobicising greasing is carried out in the presence of a 20% solution of the product of reacting amino alcohol with fatty acids of vegetable oils of the C12-C22 fraction and boric acid in molar ratio of 2:1:1 in mineral oil in amount of 0.5-1.5% of the weight of the semi-finished product.

EFFECT: good hygienic properties of hydrophobic leather and prolonged fungus resistance of the leather in high humidity and temperature conditions.

2 tbl, 5 ex

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