CN113061669A - Enzyme unhairing method for protecting skin grain surface by carrying out calcium salt mineralization coating on skin surface - Google Patents
Enzyme unhairing method for protecting skin grain surface by carrying out calcium salt mineralization coating on skin surface Download PDFInfo
- Publication number
- CN113061669A CN113061669A CN202110405641.5A CN202110405641A CN113061669A CN 113061669 A CN113061669 A CN 113061669A CN 202110405641 A CN202110405641 A CN 202110405641A CN 113061669 A CN113061669 A CN 113061669A
- Authority
- CN
- China
- Prior art keywords
- skin
- depilation
- enzyme
- calcium salt
- animal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C1/00—Chemical treatment prior to tanning
- C14C1/06—Facilitating unhairing, e.g. by painting, by liming
- C14C1/065—Enzymatic unhairing
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Treatment And Processing Of Natural Fur Or Leather (AREA)
Abstract
The invention discloses a method for protecting grain surfaces of raw hide by carrying out mineralization coating on the surface of the hide by using sedimentary calcium salt before animal hide enzyme unhairing, and relates to the field of leather production. The invention is characterized in that the sedimentary calcium salt is mineralized to protect the surface of animal skin grains, so that the calcium salt is deposited and coated on the surface of the raw skin, and the collagen is endowed with stronger enzyme resistance, and then enzymatic depilation is carried out. The method can effectively protect the grain surface layer collagen of the animal skin from being excessively acted by protease in the enzyme unhairing process, avoid the grain surface damage conditions such as loose surface, rotten surface and the like, does not influence the subsequent working section, and effectively improves the leather quality. The method has wide applicability, and is suitable for production of various leathers using animal skins as raw materials.
Description
Technical Field
The invention relates to the field of leather processing by taking animal skins as raw materials, in particular to a method for protecting the surfaces of skins and grains by mineralizing the surfaces of animal skins and grains by using sedimentary calcium salt before the animal skins are dehaired by enzyme.
Background
In the conventional leather making process, in order to remove leather making useless objects such as fur on animal skins, excessive lime and sulfide are required to be used for treating the animal skins, and a large amount of pollution is generated. The protease-based leather-making biotechnology, especially the protease unhairing technology, is one of the main development directions of the leather-making cleaning technology due to the advantages of cleanness, greenness, high efficiency and the like.
The existing enzyme-method unhairing process has the problems of easy grain surface damage, loose surface, rotten surface and reduced leather performance and quality. This is mainly due to the fact that when protease is used to treat tannery hides, excessive enzymatic degradation of collagen is often caused. With the rapid development of biotechnology, the variety of enzyme preparations is increasing, and although more enzyme choices are provided for enzyme depilation technology, the problem of excessive action on the surface of the skin grains in the enzyme depilation process is still not well solved. In order to solve the problems of protease in leather-making unhairing, the effect of the protease on the surface of the leather grain needs to be regulated, the regulation strategy from the perspective of a substrate can change the tolerance degree of specific structural protein in the leather to the protease in a targeted manner, and the damage to the collagen of the surface of the leather grain is avoided or reduced while the purpose of corresponding process is realized by enzymolysis of mixed protein in the leather.
The main structural component of the animal skin is collagen, in the vertebrate body, calcium ions exist in the form of hydroxyapatite and are highly orderly compounded with type I collagen to form bones and teeth with excellent physicochemical properties and enzyme resistance. This mechanism indicates that calcium salt has good affinity with collagen, and its ordered binding to collagen can give collagen biomaterial good mechanical strength and biostability. Further in vitro mineralization studies show that calcium ions can be combined with oxygen atoms of collagen during mineralization and can influence the recognition and hydrolysis processes of protease on the collagen by changing the conformation of collagen molecules. The surface of collagen fiber or skin grain surface is coated and mineralized by calcium salt, on one hand, an insoluble calcium salt coating layer can be formed on the surface of the collagen fiber or skin, so that the mass transfer process of a solid-liquid interface is effectively inhibited, and the improvement of the enzymolysis resistance of the collagen is realized; on the other hand, the stability of the collagen can be improved, so that the collagen is more resistant to protease hydrolysis.
Disclosure of Invention
The invention aims to provide a novel method aiming at the process problem that the existing enzyme unhairing method is easy to cause damage to the surface of animal skin grain, and the insoluble calcium salt is orderly deposited and coated on the surface of the animal skin in a solution environment to protect the surface of the animal skin grain to be unhaired from excessive action of unhairing enzyme, so that a leather product with higher grain integrity is obtained, and the problems of loose and rotten surfaces and the like easily caused by the existing enzyme unhairing process are solved.
The novelty of the invention is mainly that the operation of treating animal skin by using calcium salt mineralization coating is added before enzyme depilation of the traditional tanning process, based on the research idea of bionics, insoluble calcium salt is orderly deposited and coated on the surface of collagen fiber in a solution environment, a biomineralization mechanism is simulated to protect the collagen fiber, and then the reversible regulation and control of the enzymolysis resistance of skin collagen are realized, and a grain surface protection means which can be applied to enzyme depilation is constructed.
The invention is characterized in that before the depilation by protease, the animal skin is mineralized by using sedimentary calcium salt, a stable calcium salt protective layer is formed on the grain surface of the skin surface layer in a targeted manner, the collagen of the grain surface layer of the skin is endowed with stronger enzymolysis resistance, the excessive action of the protease on the grain surface of the skin in the depilation process by the enzyme method is avoided, and the leather product with good grain surface is obtained.
The method for protecting the grain surface in the animal skin enzymatic depilation for realizing the above purpose of the invention is characterized by comprising the following operation steps of using the materials in all the steps in parts by mass:
adding 100 parts of raw leather soaked by a conventional leather making process into a rotary drum, adding 30-300 parts of water, adding 0.5-10 parts of soluble calcium salt or calcium hydroxide at the temperature of 15-30 ℃, and rotating for 5-120 minutes; adding 0.5-10 parts of phosphate, phosphoric acid or carbonate, adjusting the pH value of the solution in the drum to 3-6, rotating for 5-120 minutes, adding a proper amount of alkaline material, adjusting the pH values of the bath liquid and the animal skin to 7-10, and starting mineralization coating, wherein the total time of the mineralization coating is 0.5-24 hours; adding appropriate amount of acidic or alkaline material, adjusting pH of bath liquid and animal skin to pH required for enzyme depilation, adding depilatory enzyme, and performing subsequent depilation operation according to conventional enzyme depilation process.
In the technical scheme, the method for protecting the grain surface of the skin by carrying out calcium salt mineralization coating on the skin surface in the animal dermatome depilation is characterized in that the soluble calcium salt is at least one of calcium chloride, calcium formate, calcium acetate and calcium methylsulfonate.
In the technical scheme, the method for protecting the surface of the skin and the grain surface by carrying out calcium salt mineralization coating on the surface of the skin in the animal dermatome depilation is characterized in that the used phosphate is at least one of orthophosphate, hydrogen phosphate and dihydrogen phosphate; the carbonate is at least 1 of soluble carbonate or bicarbonate.
In the technical scheme, the method for protecting the surface of the skin and the grain surface by carrying out calcium salt mineralization coating on the surface of the animal skin in the animal skin enzyme depilation is characterized in that after the animal skin is mineralized and coated by calcium salt, the pH values of bath liquid and the animal skin are adjusted to the pH value required by enzyme depilation, and then the depilation enzyme is added.
In the technical scheme, the method for protecting the skin grain surface in the animal dermatome depilation is characterized in that the depilatase is a composite depilatase composed of various proteases or a plurality of proteases.
In the technical scheme, the method for protecting the grain surface of the leather in the animal leather enzyme depilation is characterized by being suitable for the enzyme depilation in the leather processing process by taking various animal skins as raw materials.
The invention has the following advantages:
the invention provides a method for protecting skin grain surface in animal skin enzyme depilation, which can effectively protect the grain surface from the excessive action of protease through loose and ordered deposition and coating of micron-sized calcium phosphate salt. Meanwhile, pores with micron scale exist among calcium phosphate salt particles, and the permeation of the unhairing enzyme and the realization of the unhairing process are not influenced.
The method has good pertinence, when the animal skin is mineralized by using the calcium salt, a stable calcium salt protective layer can be formed on the grain surface part of the skin surface in a targeted manner, and the enzymolysis resistance of the grain surface collagen is improved by inhibiting the mass transfer process of a solid-liquid interface.
The method has good controllability, the protection degree of the mineralization of the calcium salt can be quantitatively controlled by the dosage of the calcium ions and the phosphate radical or the carbonate ions, the higher the dosage is, the stronger the protection effect is, and the protection effect can be adaptively adjusted according to the requirements of the enzyme depilation process.
The method has good reversibility, the calcium phosphate salt and the calcium carbonate salt are easy to dissolve in acidic solution, the protection effect can be completely removed through the subsequent pH adjustment and the processes of deliming and pickling, and no negative influence is caused on the subsequent process.
The method has good process compatibility, and can be adaptively applied to a plurality of enzyme treatment processes in the leather-making production process according to the requirements of specific leather, including soaking, unhairing, softening and the like.
The method has good universality, can be used for grain surface protection in enzymatic unhairing of various animal skins such as pigskin, sheep skin, goat skin, cow skin, rabbit skin and the like, improves the tolerance of the treated grain surfaces of the animal skins to proteases of different types and sources, is suitable for various leather manufacturing processes (such as clothing leather, shoe upper leather, sofa leather, shoe lining leather, suede leather, automobile cushion leather and the like), and can obtain finished leather with more complete grain surfaces and higher value and quality.
Drawings
FIG. 1 is a graph showing the effect of a calcium formate-sodium dihydrogen phosphate dihydrate mineralization coating on the grain surface of finished leather.
FIG. 2 shows the effect of calcium chloride-monopotassium diphosphate mineralization coating on the grain surface of finished leather.
Detailed Description
The present invention is described in detail by way of examples, it should be noted that the examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and those skilled in the art can make modifications and adjustments in the non-essential aspects based on the above disclosure.
Example 1 mineralization treatment of cow leather, sofa leather after soaking in Water, alkaline protease depilation
Adding 100kg of cow skin after conventional soaking into water, adding rotary drum, adding 30kg of water, adjusting temperature to about 15 deg.C, adding 0.5kg of calcium formate to introduce calcium ions, rotating for 120 min, adding 0.5kg of sodium dihydrogen phosphate dihydrate, rotating for 120 min, stopping the drum for 30 min, slowly adding dilute sodium hydroxide solution, controlling bath pH at about 10, stopping the drum overnight, adjusting pH to 10-10.5 the next day, unhairing with LKT alkaline protease (Shandonglongketer enzyme preparation Co., Ltd.) under 80U/mL dosage condition, rotating for 2 hr, adding lime 0.5kg and sodium hydrosulfide 0.5kg, rotating for 40 minutes, adding expanding agent RCA (Beijing Jinborreli Biotechnology Co., Ltd.) 0.7kg and water 50kg twice after the hair is completely removed, rotating for 40 minutes, stopping blowing overnight, splitting, deliming, softening and pickling the gray leather, and performing the conventional sofa leather process until finished leather is obtained.
The result is shown in figure 1, under the same enzyme unhairing process condition, the surface of the leather of the dairy cow which is directly unhaired without treatment is mottled and fuzzy, and the grain surface is completely destroyed by protease, while the leather which is subjected to enzyme unhairing after the mineralization treatment by the method has full and three-dimensional grain surface, complete and visible pores, clear grain lines and obviously better leather quality.
Example 2 mineralization of cattle hide shoe upper leather after soaking in Water, neutral protease depilation
Adding 100kg of conventional soaked cattle hide into a rotary drum, adding 300kg of water, adjusting the temperature to 30 ℃, adding 10kg of calcium chloride to introduce calcium ions, rotating for 5 minutes, adding 10kg of dipotassium phosphate, slowly adding dilute hydrochloric acid to adjust the pH to 3, rotating for 5 minutes, stopping the drum for 1 hour, slowly adding a dilute sodium hydroxide solution, controlling the pH of the bath solution to be about 7, carrying out mineralization treatment for 30 minutes, unhairing by using LKT neutral protease (Shandong Kete enzyme preparation Co., Ltd.) under the condition of 60U/mL dosage, rotating for 3 hours, adding 0.6kg of RCB (Beijing Jinborake Biotech Co., Ltd.), adding 0.5kg of lime, 0.5kg of sodium hydrosulfide, stopping the rotation for 30 minutes, adding 1kg of expanding agent (RCA, Beijing Jinborake Biotech Co., Ltd.) twice after hair is completely removed, stopping the rotation for 40 minutes, stopping the drum for 40 minutes, and removing the lime skin, deliming, softening and pickling, the finished leather is obtained according to the conventional shoe upper leather process.
The result is shown in figure 2, under the same enzyme unhairing process condition, the grain surface of the cattle hide which is directly unhaired without treatment has obvious damage and loose hand feeling, while the finished leather which is subjected to enzyme unhairing after the calcium phosphate salt mineralization treatment in the method has flat and smooth grain surface, complete and clear pores and obviously better finished leather quality.
Example 3 mineralization of goat garment glove leather after Water immersion, alkaline protease dehairing
100kg of soaked and degreased goat skin is added into a rotary drum, 30kg of water is added, the temperature is adjusted to 30 ℃, 0.5kg of calcium hydroxide is added to introduce calcium ions, the rotary drum is rotated for 5 minutes, 1kg of phosphoric acid is added, the pH value is adjusted to 4, the rotary drum is rotated for 60 minutes, a dilute sodium hydroxide solution is slowly added to control the pH value of bath liquid to be about 8, the rotary drum is stopped overnight, the pH value is adjusted to be within the range of 10-11 the next day, U enzyme (Langsheng chemical company Limited) is used for unhairing under the condition of 60U/mL dosage, the rotary drum is rotated for 2.5 hours, 0.5kg of lime is added, 0.5kg of sodium hydrosulfide is rotated for 40 minutes, 0.7kg of expanding agent RCA (Beijing Jinbiri Kao-Keelix Biotech Co., Limited) is added twice after the unhairing, the hair is stopped for 40 minutes, the rotary drum is stopped overnight, and the grey skin is subjected to deliming, softening and.
The result shows that under the same enzyme unhairing process condition, the finished grain surface of the goat clothing leather subjected to enzyme unhairing after mineralization treatment by the method is obviously superior to that of the goat leather directly subjected to enzyme unhairing without treatment.
Example 4 mineralization of pig front clothing leather after soaking in Water, neutral protease depilation
100kg of soaked and degreased pigskin is added into a rotary drum, 50kg of water is added, the temperature is adjusted to about 25 ℃, 3kg of calcium chloride is added to introduce calcium ions, the rotary drum is rotated for 5 minutes, the pH is adjusted to 6, 5kg of sodium carbonate is dissolved in the water, the rotary drum is slowly added, the pH of bath liquid is controlled to be about 7, the drum is stopped for 5 hours, the pH is adjusted to be within the range of 7-7.5, the hair is unhaired by using As1.398 neutral protease under the condition of 70U/mL dosage, the rotary drum is rotated for 3 hours, 0.6kg of RCB (Beijing Jinborrelix Biotech Co., Ltd.) is added, 1kg of lime and 0.6kg of sodium hydrosulfide are added, the rotary drum is stopped for 30 minutes, 1kg of expanding agent (Beijing Jinborrelix Biotech Co., Ltd.) is added twice after the hair is completely removed, the water is 40kg, the rotary drum is stopped for 40 minutes, the RCA is stopped overnight, the pigskin is subjected to flaking, deliming.
Claims (6)
1. A method for protecting the surface of leather grains by carrying out calcium salt mineralization coating on the surface of the leather in animal dermatome depilation is characterized by comprising the following operation steps, wherein the materials used in the steps are calculated according to parts by mass and specifically operated as follows:
adding 100 parts of raw leather soaked by a conventional leather making process into a rotary drum, adding 30-300 parts of water, controlling the temperature to be 15-32 ℃, adding 0.5-10 parts of soluble calcium salt or calcium hydroxide, and rotating for 5-120 minutes; adding 0.5-10 parts of at least 1 of phosphate, phosphoric acid and carbonate, adjusting the pH value of the solution in the drum to 3-6, rotating for 5-120 minutes, adding a proper amount of alkaline material, adjusting the pH values of the bath liquid and the animal skin to 7-10, and starting mineralizing and coating, wherein the total time of mineralizing and coating is 0.5-24 hours; adding appropriate amount of acidic or alkaline material, adjusting pH of bath liquid and animal skin to pH required for enzyme depilation, adding depilatory enzyme, and performing subsequent depilation operation according to conventional enzyme depilation process.
2. A method of protecting the grain side of animal skin by applying a calcium salt mineralizing coating to the skin surface in the enzymatic dehairing of the animal skin according to claim 1 wherein the soluble calcium salt is at least one of calcium chloride, calcium formate, calcium acetate, calcium methanesulfonate.
3. A method of protecting the grain surface of the skin by calcium salt mineralizing the skin surface in animal skin enzyme depilation according to claim 1, wherein the phosphate used is at least one of orthophosphate, hydrogen phosphate, dihydrogen phosphate; the carbonate is at least 1 of soluble carbonate or bicarbonate.
4. A method of protecting the grain surface of animal skin by mineralizing and coating the skin surface with calcium salt in the enzymatic depilation of animal skin according to claim 1, wherein after mineralizing and coating the animal skin with calcium salt, the pH of the bath and the animal skin are adjusted to the pH required for enzymatic depilation and the depilation enzyme is added.
5. A method of protecting the grain surface in the depilation of animal skin enzymes according to claim 1, wherein the depilation enzyme used is a complex depilation enzyme consisting of various proteases or a plurality of enzymes containing proteases.
6. A method of protecting the grain side of animal hides in enzymatic depilation according to claims 1 to 5, which is suitable for enzymatic depilation in leather processing processes starting from various animal hides.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110405641.5A CN113061669B (en) | 2021-04-15 | 2021-04-15 | Enzyme unhairing method for protecting skin grain surface by carrying out calcium salt mineralization coating on skin surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110405641.5A CN113061669B (en) | 2021-04-15 | 2021-04-15 | Enzyme unhairing method for protecting skin grain surface by carrying out calcium salt mineralization coating on skin surface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113061669A true CN113061669A (en) | 2021-07-02 |
| CN113061669B CN113061669B (en) | 2022-03-29 |
Family
ID=76566716
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110405641.5A Active CN113061669B (en) | 2021-04-15 | 2021-04-15 | Enzyme unhairing method for protecting skin grain surface by carrying out calcium salt mineralization coating on skin surface |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113061669B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102178228A (en) * | 2011-04-18 | 2011-09-14 | 陕西巨子生物技术有限公司 | Collagen-calcium chelate and preparation method thereof |
| CN104711379A (en) * | 2015-02-12 | 2015-06-17 | 四川大学 | Enzyme unhairing method for removing damage to cowhide leather grain surface |
| CN107893133A (en) * | 2017-11-09 | 2018-04-10 | 四川大学 | A kind of process hides ox-hide enzymatic depilation method |
-
2021
- 2021-04-15 CN CN202110405641.5A patent/CN113061669B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102178228A (en) * | 2011-04-18 | 2011-09-14 | 陕西巨子生物技术有限公司 | Collagen-calcium chelate and preparation method thereof |
| CN104711379A (en) * | 2015-02-12 | 2015-06-17 | 四川大学 | Enzyme unhairing method for removing damage to cowhide leather grain surface |
| CN107893133A (en) * | 2017-11-09 | 2018-04-10 | 四川大学 | A kind of process hides ox-hide enzymatic depilation method |
Non-Patent Citations (1)
| Title |
|---|
| 李桂芝等: "《生物无机化学导论》", 31 March 1997, 哈尔滨工程大学出版社 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113061669B (en) | 2022-03-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107893133B (en) | A kind of process hides ox-hide enzymatic depilation method | |
| CN111321258A (en) | Production process of leather | |
| CN112322806B (en) | Method for producing transparent leather based on organic tanning agent | |
| CN101230408A (en) | Non-chroming processing method for leather production | |
| CN113061669B (en) | Enzyme unhairing method for protecting skin grain surface by carrying out calcium salt mineralization coating on skin surface | |
| CN113913563B (en) | Deliming-softening-pickling integrated clean leather making method and application thereof | |
| US4636222A (en) | Enzymatic unhairing method | |
| CN101319254A (en) | Cleaning treatment process for cow leather | |
| US3254938A (en) | Leather tanning | |
| CN110129489B (en) | Method for preparing chrome-free pickled skin | |
| CN112961946B (en) | Method for protecting skin grain surface in enzymatic unhairing of animal skin | |
| CN110643754B (en) | Method for regulating protease catalytic activity in tanning process | |
| CN110144424B (en) | Processing technology for preparing retainable wet blue leather by using low-grade grey fur | |
| JP4114046B2 (en) | Enzymatic hair removal treatment and enzymatic hair removal method | |
| CN109609484B (en) | Preparation method of composite depilatory enzyme preparation and application of composite depilatory enzyme preparation in depilation of imported oxhide containing feather | |
| CN1427084A (en) | Processing method of making leather using frog skin | |
| CN109880939B (en) | Auxiliary agent for strengthening mass transfer of protease in skin and application thereof | |
| US2857317A (en) | Treatment of skins and hides | |
| WO2001042513A1 (en) | Enzymatic unhairing agent for use in tanning for producing leather and method for enzymatic unhairing treatment | |
| KR100871597B1 (en) | A process for improving softness and/or area yield of leather | |
| US2212750A (en) | Method of treating hides, skins, and pelts | |
| CN109880943B (en) | Salt-free pickling-free animal skin chrome tanning method based on synergistic effect of composite ligand | |
| KR100441377B1 (en) | Method for preparation of leather using protease and method for treatment of wastes derived from leather production process using the same | |
| CN117587173A (en) | Softening method for preventing leather damage | |
| KR20190000635A (en) | Manufacturing method of corduban leather applying environment-friendly method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |