阅读说明：本技术 一种鲟鱼皮制革的方法 (Method for making leather from sturgeon skin ) 是由 张金伟 税科林 于 2019-09-27 设计创作，主要内容包括：一种鲟鱼皮制革的方法,其特征在于鲟鱼皮经过保骨板→去肉→脱脂→浸水→松散纤维→脱灰软化→氧化漂白→还原漂白→浸酸→去酸→铬鞣等工序加工即可获得蓝湿革,蓝湿革可按照现有技术进行复鞣、染色、加脂和涂饰等后续操作。鲟鱼皮制革过程中通过对骨板和粒面的保护以及在工序在具有曝气功能的划槽中进行,可以防止硬质骨板和粒面损伤；制革过程中通过长时间均匀缓和的膨胀和浸酸等操作松散胶原纤维,成革柔软丰满；通过氧化和还原进行漂白,可以基本消除天然色素。本发明提供的一种鲟鱼皮制革的方法实用性强,可以用于加工不同种类的鲟鱼皮,加工所得蓝湿革后又可根据成品要求进行不同的鞣后湿加工和涂饰操作。(A method for preparing leather from sturgeon skin is characterized in that the sturgeon skin is processed through the procedures of bone plate protection → fleshing → degreasing → soaking → loose fiber → deliming softening → oxidative bleaching → reductive bleaching → pickling → deacidification → chrome tanning, and the like to obtain the wet blue leather, and the wet blue leather can be subjected to the subsequent operations of retanning, dyeing, fatliquoring, coating, and the like according to the prior art. The hard bone plate and the grain surface can be prevented from being damaged by protecting the bone plate and the grain surface and carrying out the working procedure in the groove with the aeration function in the process of making the leather from the sturgeon skin; loosening collagen fibers through operations such as long-time uniform and mild expansion, pickling and the like in the leather making process, so that the finished leather is soft and full; bleaching by oxidation and reduction can substantially eliminate natural pigments. The method for making leather from sturgeon skin provided by the invention has strong practicability, can be used for processing different types of sturgeon skin, and can perform different operations of post-tanning wet processing and coating according to the requirements of finished products after processing the obtained blue wet leather.)

1. A method for preparing leather from sturgeon skin is characterized in that the sturgeon skin is processed by the procedures of bone plate protection → fleshing → degreasing → soaking → loose fiber → deliming softening → oxidation bleaching → reduction bleaching → pickling → deacidification → chrome tanning, and the like to obtain the wet blue leather which can be subjected to the subsequent operations of retanning, dyeing, fatliquoring, coating, and the like according to the prior art; the working procedures are all carried out in a paddle vat with an aeration function, the material dosage in each working procedure is based on the weight of the sturgeon raw material skin, and the concrete operation of the working procedures is as follows:

bone protection plate: adding water with the weight of 400-500%, penetrant 0.5-1.0%, degreasing agent 0.5-1.0%, bactericide 0.2-0.5% and aldehyde substance 0.2-0.6% into sturgeon raw material skin, soaking for 18-24h under the conditions of paddling and aeration, draining and washing with water;

removing meat: the sturgeon skin meat surface treated by the bone-protecting plate faces upwards, is nailed on a wood plate by a nail, and is grinded by a grinder provided with a steel wire wheel to remove the subcutaneous tissue and fat of the skin;

degreasing: soaking the sturgeon skin after fleshing in water with the weight of 400-;

soaking: soaking the degreased sturgeon skin in water with the weight of 400-;

loose fibers: soaking sturgeon skin soaked in water with the weight of 400-500%, adding 0.5-1.0% of penetrating agent, 1.0-2.0% of degreasing agent, 1.0-3.0% of liming auxiliary agent and 0.2-0.4% of aldehyde substance, soaking for 1h under the condition of scratching and aeration, adding 0.8-2.0% of sodium hydrosulfide, soaking for 1-3h under the condition of scratching and aeration, adding 0.5-1.5% of sodium sulfide, 1.0-3.0% of lime and 1.0-3.0% of liming auxiliary agent, soaking for 2-4h under the condition of scratching and aeration, adding 1.0-3.0% of lime and 1.0-3.0% of liming auxiliary agent, soaking for 6-9h under the condition of scratching and aeration, adding 1.0-3.0% of lime, soaking for 4-6h under the condition of scratching and aeration, adding 1.0-3.0% of liming auxiliary agent, soaking for 4-6h under the condition of scratching and aeration, after all materials are added, intermittently performing scratching and aeration, wherein the total fiber loosening time is 96-144h, and washing after liquid drainage;

deliming and softening: soaking sturgeon skin with loose fibers in water with the weight of 400 plus materials of 500%, adding 1.0-2.5% of deliming agent, soaking for 1-3h under the conditions of paddling and aeration, washing after liquid discharge, adding water with the weight of 400 plus materials of 500% and 2.0-5.0% of deliming agent, soaking for 1-3h under the conditions of paddling and aeration, adding 0.2-0.5% of softening enzyme, soaking for 12-18h under the conditions of paddling and aeration, and washing after liquid discharge;

oxidizing and bleaching: soaking the delimed and softened sturgeon skin in water with the weight of 400-500%, adding 1.0-6.0% of oxidant, soaking for 1-5h under the conditions of paddling and aeration, adjusting the pH value of bath liquid to 8.0-9.5 by using acid or alkali, draining liquid and washing by water;

reduction bleaching: soaking the sturgeon skin after oxidation bleaching in 60g/L sodium chloride aqueous solution with the weight of 400-500%, adding 2-4% of reducing agent, soaking for 2-6h under the conditions of paddling and aeration, and adjusting the pH value of bath liquid to 3.5-5.0 by using sulfuric acid in the process;

pickling: soaking the sturgeon skin subjected to reduction bleaching in a 60g/L sodium chloride aqueous solution with the weight of 400-500%, adding 0.5-2.0% of organic acid, soaking for 2-6h under the conditions of paddling and aeration, adding sulfuric acid to enable the pH value of bath liquid to be 1.0-2.0, soaking for 8-10h under the conditions of paddling and aeration, intermittently paddling and aerating after all materials are added, and carrying out total pickling for 72-120 h;

acid removal: adding alkaline substances into the bath liquid after pickling, and soaking for 2-4h under paddling and aeration conditions to ensure that the pH value of the bath liquid is 2.8-3.3;

chrome tanning: adding 5-12% chrome tanning agent, 3-6% alum and 2-4% modified glutaraldehyde into the deacidified bath liquid, soaking for 36-48h under the paddling and aeration conditions, then utilizing sodium bicarbonate to adjust the pH value of the bath liquid to 3.6-4.0 under the paddling and aeration conditions for six times, and keeping the interval of 1h every time, finally heating the bath liquid to 40 ℃, and keeping the temperature for 12-24h under the paddling and aeration conditions;

the blue wet leather can be obtained by tanning through the above process operations, and the temperature is normal temperature when other processes are carried out except the described process operations.

2. The sturgeon skin tanning method according to claim 1, characterized in that sturgeon raw skin is any one of salt wet skin or 75% ethanol solution soaked for 72 h.

3. A method of making leather from sturgeon skin according to claim 1 or 2, characterized in that the sturgeon skin is any one of acipenser dabryanus, acipenser ruthensis, acipenser baeri, acipenser brevifilis or hybrid sturgeon.

4. The sturgeon skin tanning method according to claim 1, characterized in that the aldehyde substance is any one of formaldehyde, glutaraldehyde or modified glutaraldehyde.

5. The sturgeon skin tanning method as claimed in claim 1, wherein the deliming agent is one or both of ammonium sulfate, ammonium chloride and an ammonium-free deliming agent.

6. The sturgeon skin tanning method according to claim 1, characterized in that the oxidant is any one of potassium permanganate, hydrogen peroxide, potassium chromate or sodium hypochlorite.

7. The sturgeon skin tanning method as claimed in claim 1, wherein the reducing agent is one or two of oxalic acid, sodium sulfite, sodium bisulfite and potassium iodide.

8. The sturgeon skin tanning method according to claim 1, characterized in that the organic acid is any one of formic acid, acetic acid, citric acid or lactic acid.

9. The method for tanning sturgeon skin according to claim 1, characterized in that the alkaline substance used in the deacidification is one or two of sodium carbonate, sodium thiosulfate, sodium sulfite and sodium bicarbonate.

Technical Field

The invention belongs to the technical field of leather production and processing, and particularly relates to a processing technology for making leather from sturgeon skin.

Background

Sturgeon is a general term of fishes in Acipenserformes, originates from the mud pot age about 4.5 ~ 3.5.5 hundred million years ago today, belongs to Osteichthyes, RADIAXIABIA, Total order of cartilage and Scale, and Acipenserales, and is a kind of original cartilage and Scale fishes.

More importantly, the sturgeon has extremely high economic value. Sturgeon bone can inhibit cancer cell division, sturgeon meat has effects of caring skin, lowering blood pressure and blood lipid, nourishing brain, invigorating kidney, etc., and sturgeon liver and viscera can also be made into various foods. Sturgeon roe can be processed into caviar, and is called 'three-kind world food together with goose liver and truffle', sturgeon roe is a main species in sturgeon trade in the world and is also the most main income in sturgeon culture process in China.

In the development process of sturgeon products, the resource utilization of sturgeon skin is relatively weak. According to incomplete statistics, about 1000 tons of sturgeon skin is discarded because the sturgeon skin cannot be effectively utilized every year in China, so that precious biomass resources are wasted, and the environment is polluted. The development of a way for high-quality resource utilization of sturgeon skin becomes more and more important. At present, the sturgeon skin can be used for extracting collagen polypeptide (Liao, yellow morning, Jianghong, etc.. the response surface method optimizes the enzymolysis process [ J ] of the sturgeon skin collagen polypeptide, food technology, 2018, 4(1): 141-plus 147) and tanning (Zhangjie, the tanning process research of artificially cultured sturgeon skin [ D ] of the university of Wuhan engineering, 2012).

The sturgeon skin has special patterns, particularly five bone plates distributed on the skin, and is a special structure which is not possessed by other types of raw material skins, and the natural patterns of the sturgeon skin cannot be imitated by adopting other raw material skins. Therefore, the sturgeon skin has wide market prospect when being used for tanning. In the leather making process of the sturgeon skin, the bone plate is embedded in the skin, so that the processing technology required in the leather making process is greatly different from that of the traditional leather making process.

Disclosure of Invention

The inventor finds that the prior art has the following problems by researching the published technical data of making leather by using the sturgeon skin: plum macrostrong (plum macrostrong. sturgeon skin tanning method and sturgeon skin prepared by the method, CN 102154529A) only uses acid conditions in the process of tanning sturgeon skin, and in order to improve the softness and fullness of finished products in the conventional tanning process, liming is often needed, the common knowledge in the tanning industry is that the skin is well taken out of a ashtray, the sturgeon skin processed by the method is poor in the softness and fullness of finished leather due to the lack of the loosening effect of soda on fibers; an environment-friendly sturgeon skin tanning process, CN 103436643A, adopts pickling and then bleaching, and finally pickling and tanning are carried out again, the same procedures in the method are repeated, and waste of chemical raw materials is caused.

The inventor provides a method for making leather from sturgeon skin on the basis of carefully researching and disclosing sturgeon skin leather-making technology, sturgeon skin histology, leather-making chemistry and technology and leather-making mechanical equipment.

In the method, the leather making of the sturgeon skin is not carried out in a rotary drum commonly used for making leather, because the mutual friction between skins is severe in the rotating process of the rotary drum, and the skins have severe mechanical actions such as beating, bending and the like in the running process of the rotary drum, the interaction between a sturgeon skin bone plate and a bone plate and between the bone plate and scales is too strong, so that the bone plate is easy to wear, loosen and even fall off, and the grain surface can be damaged, therefore, the friction between the skins in the processing process is reduced as much as possible, and the severe mechanical actions such as beating, bending and the like are avoided. Carry out sturgeon skin tanning experiment in the groove of drawing that the fur coat is commonly used, if the paddle is drawn for a long time, also can cause the damage because of the friction between the skin, if further increase the liquid ratio of tanning in-process, not only can increase the waste water discharge, chemical material consumes also bigger, is unfavorable for practical application. However, the short paddle-stroke time can cause uneven distribution of the chemical materials in the bath solution, and the mechanical action of the system is too weak, so that the penetration rate of the chemical materials into the skin is reduced, the processing time or the dosage needs to be prolonged, and the method is not economical. The inventor reforms transform current scratch groove, at the trachea that scratch groove bottom installation punched, continuously aerates with compressed air in the tanning course of working to reduce the paddle and scratch the time, provide certain mechanical action again simultaneously, promote chemical material to intradermal infiltration, and make it distribute evenly in the bath lotion.

Five rows of hard bone plates on the sturgeon skin are embedded in the skin plate, the joint of the bone plate and the skin is only provided with a thin layer, once the skin connected with the thin layer is damaged or degraded in the processing process, the bone plate is easy to loosen or even fall off, and the quality of the finished leather is affected. In addition, although sturgeon skin collagen is typical type i collagen, its denaturation temperature is about 28 ℃, which is significantly lower than that of bovine achilles tendon collagen (42.81 ℃), and its resistance to enzymatic degradation is also inferior to that of bovine achilles tendon collagen (yanling, zhao yan, luliang, etc.. extraction of sturgeon skin collagen and its analysis of its physicochemical properties [ J ] food science, 2013, 34(23): 41-46). Therefore, in order to ensure that the bone plate does not fall off during the processing, the inventor firstly utilizes the characteristic that aldehydes can rapidly react with collagen, and firstly carries out the bone plate protecting process. In the process, a small amount of aldehyde substances are added to react with collagen on the surface of the leather plate to generate tanning effect, so that the enzymolysis resistance of the leather plate is improved, and the collagen at the joint of the bone plate and the leather plate is not easy to damage in the subsequent processing process of the sturgeon skin. Meanwhile, the using amount of the aldehyde substances is 0.2-0.6% of the weight of the sturgeon raw material skin, so that surface over-tanning is not caused, the grain surface appearance is not changed, and the removal of the fiber matrix and the loosening effect on the fiber in the subsequent operation are not influenced.

The hard bone plate on the sturgeon skin prevents the sturgeon skin from being fleshed by a fleshing machine or a bent knife, but the sturgeon skin is also greasy skin and must be fleshed. In the prior art, the meat is removed by using steel wire balls, so that the efficiency is low and the effect is limited. The inventor carries out fleshing through adorning the steel wire wheel on adjustable speed's buffing machine, and is not only efficient, and is effectual moreover, can not harm the skin again simultaneously. Meanwhile, the operation is carried out manually, the bone plate can be repeatedly polished in places with much grease, when the grease existing after the bone plate is removed, the polishing machine can be erected, the edge of the steel wire wheel is used for removing the meat, and the grease in the bone plate can be completely removed. After the fleshing operation, the sturgeon skin is degreased by a saponification method of a surfactant and alkali and lipase, so that the fat content in the skin is reduced.

The sodium sulfide and lime can swell the raw hide, and remove impurity proteins such as keratin and glycoprotein, thereby achieving the purpose of loosening the fiber. However, since the collagen in the skin plate has good expansibility and the hard bone plate does not expand, if the expansion is too severe, the connection between the weak bone plate and the skin plate is broken due to the large expansion difference between the two materials during the expansion process, which generates a great internal stress, so that the bone plate is loosened and falls off, and therefore, it is important to inhibit the expansion of the skin plate during the process of loosening the fibers. The inventor adopts the method of increasing the proportion of sodium hydrosulfide in sodium sulfide, adding sodium sulfide and lime in different times and increasing the dosage of liming auxiliary agent, so as to inhibit the expansion of collagen as much as possible, and simultaneously, the expansion process is mild, thereby avoiding damaging the connection between the leather plate and the bone plate. The ash removal is also carried out step by step after the ash alkali is expanded, so that the phenomenon that the connection between the leather plate and the bone plate is damaged due to the overlarge pH value difference between the surface and the inside of the leather sheet caused by using a large amount of ash removing agent is prevented.

Sturgeon skin often appears dark color such as grey black, brown and the like on the back, and the belly is white or beige, and has characteristics of itself. The sturgeon skin mainly comes from large sturgeons with roes taken, the sturgeon skin is usually long in culture period and has a lot of scars generated in the growth process, so that a lot of light-colored irregular stripes exist on a dark area on the back, and the final product is low in grade if the sturgeon skin is not bleached. After researching the common bleaching method in the leather making process, the inventor combines the process reality, selects the oxidant which can have good bleaching effect under the alkalescent condition to bleach firstly, then carries out reduction bleaching under the acidic condition, and can basically make the pelts present the uniform color from white to beige through twice bleaching. The oxidation bleaching is carried out under the alkalescent condition, the procedure of deliming and softening can be followed, then the reduction bleaching is carried out under the acidic condition, and the pickling operation can be carried out after the completion, so that the technical process is continuous, and the collagen fiber is prevented from being damaged due to the large fluctuation of the pH value or the large-range adjustment of the pH value for many times.

The inventor adds sulfuric acid and prolongs the pickling time in the pickling process, so that the aim of fully loosening fibers is fulfilled, and more importantly, hydroxyapatite in the bone plate is partially dissolved to soften the bone plate, so that the sturgeon skin can be subjected to severe mechanical processing in the retanning, dyeing and fatliquoring processes without causing the conditions of scratching, bone plate falling and the like. The pH value after pickling is very low, if tanning is directly carried out, alkali extraction at the final stage of tanning is difficult, the defects of chromium flower and the like are generated due to excessive alkali extraction times, and the plumpness of finished leather is reduced due to the low pH value at the initial stage of tanning. Thus tanning is preceded by first deacidification.

The tanning adopts chrome tanning agent as main material, and aluminum tanning agent and aldehyde tanning agent are matched at the same time. The use amount of the chrome tanning agent can be properly reduced after the aluminum tanning agent is added, so that the finished leather has the characteristics of chrome tanning and lighter blue color tone, and is suitable for processing light-colored leather. The modified glutaraldehyde is added, so that the finished leather has the characteristic of aldehyde tanning, and the grease in the sturgeon skin can be dispersed by utilizing the dispersing effect of the modified glutaraldehyde on natural grease, so that the penetration of a metal tanning agent is promoted.

On the basis of the research, the inventor provides a sturgeon skin tanning method, which is characterized in that sturgeon skin is processed through the procedures of bone plate protection → fleshing → degreasing → soaking → loose fiber → deliming softening → oxidative bleaching → reductive bleaching → pickling → deacidification → chrome tanning and the like to obtain wet blue leather, and the wet blue leather can be subjected to the subsequent operations of retanning, dyeing, fatliquoring, coating and the like according to the prior art; the working procedures are all carried out in a paddle vat with an aeration function, the material dosage in each working procedure is based on the weight of the sturgeon raw material skin, and the concrete operation of the working procedures is as follows: bone protection plate: adding water with the weight of 400-500%, penetrant 0.5-1.0%, degreasing agent 0.5-1.0%, bactericide 0.2-0.5% and aldehyde substance 0.2-0.6% into sturgeon raw material skin, soaking for 18-24h under the conditions of paddling and aeration, draining and washing with water;

removing meat: the sturgeon skin meat surface treated by the bone-protecting plate faces upwards, is nailed on a wood plate by a nail, and is grinded by a grinder provided with a steel wire wheel to remove the subcutaneous tissue and fat of the skin;

degreasing: soaking the sturgeon skin after fleshing in water with the weight of 400-;

soaking: soaking the degreased sturgeon skin in water with the weight of 400-;

loose fibers: soaking sturgeon skin soaked in water with the weight of 400-500%, adding 0.5-1.0% of penetrating agent, 1.0-2.0% of degreasing agent, 1.0-3.0% of liming auxiliary agent and 0.2-0.4% of aldehyde substance, soaking for 1h under the condition of scratching and aeration, adding 0.8-2.0% of sodium hydrosulfide, soaking for 1-3h under the condition of scratching and aeration, adding 0.5-1.5% of sodium sulfide, 1.0-3.0% of lime and 1.0-3.0% of liming auxiliary agent, soaking for 2-4h under the condition of scratching and aeration, adding 1.0-3.0% of lime and 1.0-3.0% of liming auxiliary agent, soaking for 6-9h under the condition of scratching and aeration, adding 1.0-3.0% of lime, soaking for 4-6h under the condition of scratching and aeration, adding 1.0-3.0% of liming auxiliary agent, soaking for 4-6h under the condition of scratching and aeration, after all materials are added, intermittently performing scratching and aeration, wherein the total fiber loosening time is 96-144h, and washing after liquid drainage;

deliming and softening: soaking sturgeon skin with loose fibers in water with the weight of 400 plus materials of 500%, adding 1.0-2.5% of deliming agent, soaking for 1-3h under the conditions of paddling and aeration, washing after liquid discharge, adding water with the weight of 400 plus materials of 500% and 2.0-5.0% of deliming agent, soaking for 1-3h under the conditions of paddling and aeration, adding 0.2-0.5% of softening enzyme, soaking for 12-18h under the conditions of paddling and aeration, and washing after liquid discharge;

oxidizing and bleaching: soaking the delimed and softened sturgeon skin in water with the weight of 400-500%, adding 1.0-6.0% of oxidant, soaking for 1-5h under the conditions of paddling and aeration, adjusting the pH value of bath liquid to 8.0-9.5 by using acid or alkali, draining liquid and washing by water;

reduction bleaching: soaking the sturgeon skin after oxidation bleaching in 60g/L sodium chloride aqueous solution with the weight of 400-500%, adding 2-4% of reducing agent, soaking for 2-6h under the conditions of paddling and aeration, and adjusting the pH value of bath liquid to 3.5-5.0 by using sulfuric acid in the process;

pickling: soaking the sturgeon skin subjected to reduction bleaching in a 60g/L sodium chloride aqueous solution with the weight of 400-500%, adding 0.5-2.0% of organic acid, soaking for 2-6h under the conditions of paddling and aeration, adding sulfuric acid to enable the pH value of bath liquid to be 1.0-2.0, soaking for 8-10h under the conditions of paddling and aeration, intermittently paddling and aerating after all materials are added, and carrying out total pickling for 72-120 h;

acid removal: adding alkaline substances into the bath liquid after pickling, and soaking for 2-4h under paddling and aeration conditions to ensure that the pH value of the bath liquid is 2.8-3.3;

chrome tanning: adding 5-12% chrome tanning agent, 3-6% alum and 2-4% modified glutaraldehyde into the deacidified bath liquid, soaking for 36-48h under the paddling and aeration conditions, then utilizing sodium bicarbonate to adjust the pH value of the bath liquid to 3.6-4.0 under the paddling and aeration conditions for six times, and keeping the interval of 1h every time, finally heating the bath liquid to 40 ℃, and keeping the temperature for 12-24h under the paddling and aeration conditions;

the blue wet leather can be obtained by tanning through the above process operations, and the temperature is normal temperature when other processes are carried out except the described process operations.

Wherein the sturgeon raw skin is any one of salt wet skin or 75% ethanol solution soaked for 72 h. The sturgeon skin is any one of acipenser dabryanus, acipenser ruthenus, acipenser baeri, acipenser brachypus or hybrid sturgeons. The aldehyde substance is any one of formaldehyde, glutaraldehyde or modified glutaraldehyde. The deliming agent is one or two of ammonium sulfate, ammonium chloride and ammonium-free deliming agent. The oxidant is any one of potassium permanganate, hydrogen peroxide, potassium chromate or sodium hypochlorite. The reducing agent is one or two of oxalic acid, sodium sulfite, sodium bisulfite and potassium iodide. The organic acid is any one of formic acid, acetic acid, citric acid or lactic acid. The alkaline substance used in deacidification is one or two of sodium carbonate, sodium thiosulfate, sodium sulfite and sodium bicarbonate.

The sturgeon skin tanning method provided by the invention has the following advantages:

1. the used equipment can be modified by additionally arranging a perforated air pipe at the bottom of the equipment on the basis of the existing leather (fur coat) cutting groove, so that the modification is simple, the cost is low, and the practicability is high;

2. the used chemical materials are common basic chemical materials and leather chemicals of a tannery, the sources are wide, the cost is low, the technology is mature, and meanwhile, the leather chemicals which have the same property and can realize the purpose of corresponding procedures can be selected according to the specific conditions of different factories, so that the application range is wide;

3. the process is reasonable in connection, avoids severe pH fluctuation in the processing process, reuses chemical materials for achieving the same purpose, reduces the production cost and period, reduces pollution and has strong operability.

Detailed Description

The following examples are given to illustrate the present invention in more detail, and it should be noted that the following examples are not to be construed as limiting the scope of the present invention, and that various insubstantial modifications and adaptations of the present invention will be made by those skilled in the art based on the above disclosure.