CN104232806A

CN104232806A - Method for manufacturing leather

Info

Publication number: CN104232806A
Application number: CN201310251371.2A
Authority: CN
Inventors: 潘龙祥
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-06-24
Filing date: 2013-06-24
Publication date: 2014-12-24

Abstract

The invention provides a method for manufacturing leather, and belongs to the technical field of leather processing. The method for manufacturing leather comprises a raw hide liming step and a raw hide re-liming step, wherein waste liquor produced in the raw hide limiting step and the raw hide re-liming step enter a same storage tank. According to the method for manufacturing the leather, raw hide with hairs firstly enter a liming bath (new lime) and then enter a re-liming bath (old lime) after hairs are removed by virtue of a modified less-bath lime-soda process, wherein the difference is that the re-liming action is strengthened. And thus, hide collagen fibers can be sufficiently and properly separated and loosened really. In both liming bath and re-liming bath, waste liquor enters the same storage tank, and the improved new system utilizes the advantages of a liming and re-liming waste liquor recycling technology. And meanwhile, more importantly, the recycling of the liming and re-liming waste liquor is realized by virtue of the combination and linkage, and thus, the pollution of limes and sodium sulfide on environment is radically removed.

Description

Make the method for leather

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Technical field

The invention belongs to leather processing technique field, particularly relate to a kind of method making leather.

Background technology

At present, the depilating method of large-scale application in cattle hide process hides mainly contains: liming (alkali) depilation, liming (alkali) protect hair depilation, roll enzyme bank up depilation and oxidative unhairing then less application.Curriery has a jargon " good skin goes out at grey cylinder ", and modern tanning technology is thought, preparation is basis is also crucial.In the beam house of cattle hide process hides, grey alkaline purification is vital.

The technological principle of modern liming may be summarized to be: bathe depilation less, repression of swelling, and the heavy ash of light alkali, evenly relaxes.Good liming should be at all levels in rawhide on uniform pickup alkali basis on, then add big yield gradually, rawhide evenly moderately expanded.No matter be traditional depilation by lime, or modern hair saving process, all inevitably there is the pollution problem of sulfide.

" three systemic circulations " refers to the recycle system of the Lime Liquor recycle system, multiple grey waste liquid circulation system and chroming waste liquor.Existing liming, the multiple grey spent lime liquor recycle system, its recycle number of times is all limited, is generally about 2 weeks.

Summary of the invention

The present invention makes the method for leather, and comprise the step of rawhide liming and the step of the multiple ash of rawhide, the waste liquid that the step of the step of described rawhide liming and the multiple ash of rawhide produces enters in same storage pool.

Make the method for leather according to the present invention, first band hair rawhide enters liming bath (newly ash), bathes less after the depilation of grey alkaline process through modification, then enters multiple ash bath (always ash), unlike, the effect of multiple ash is strengthened to some extent.Like this, materials with hide glue fibril can be made really to obtain fully, be moderately separated and loose.No matter be liming bath or multiple ash bath, its waste liquid all enters same storage pool.New system after improvement absorbs the strong point that liming-multiple grey waste liquid circulation utilizes technology, and meanwhile, what is more important, this combination and coupling achieve the recycle of liming-multiple grey waste liquid, have eradicated lime, sodium sulphite to the pollution of environment.

Embodiment

Below by specific embodiment, the present invention is further illustrated.

In ash alkali unhairing process, the degrees of expansion of rawhide depends primarily on the consumption of lime and sodium sulphite.Ash and alkali consumption larger, then rawhide expansion strong with regard to Shaoxing opera, the possibility of finished leather loose side is also larger.On the other hand, the consumption of ash and alkali is larger, and lose hair or feathers easier, the pollution of grey alkali to environment is larger.The author once used systems engineering and orthogonal design to carry out comparatively systematic research to ash alkali unhairing, propose " method of leather ash alkali unhairing ", and it was as follows to obtain setting process.

Technical stipulation: liquor ratio 0.3 ~ 0.5, temperature 22 DEG C ~ 24 DEG C, Sodium Sulfide Flakes (60%) 2.0% ~ 2.2%, lime fine powder 4%, penetrating agent JFC 0.2%, liquid caustic soda (30%) 0.6% ~ 0.8%.

Working method: after mixing up liquor ratio and interior temperature by regulation, add Sodium Sulfide Flakes and penetrating agent JFC, rotate 60min, check depilation situation, after hair purifies completely, supplementing warm water, expand liquor ratio to 2.0 ~ 2.5, adding lime fine powder and liquid caustic soda (adding from turning hole axle in rotation with after 5 times of water dilutions), rotate 60 ~ 90min, later intermittent rotary, that is: rotate 3min/60min × (4 ~ 6 times), rotate 15min after washing next day.

According to party south (Donnan) barrier film level theory; three kinds of theories such as Coulomb repulsion theory and ion provide protection; the mechanism of the method for leather ash alkali unhairing can be expressed as: the initial stage; under the condition without bath/few bath; the higher sodium sulphite liquid of relative concentration is fast by hair complete hydrolysis; and rapid permeability is to the internal layer of rawhide, inside and outside rawhide, produce larger osmotic pressure, make to be formed between rawhide collegen filament more " passage ".In the later stage, when moisturizing expands liquefaction, osmotic pressure increases further, and water molecules enters flesh side rapidly, swimmingly, enters between collegen filament, and the weight and volume of rawhide is increased, thus water-filling swelling occurs.During owing to adopting the method for leather ash alkali unhairing, the expansion of pelt is " inhibition expansion ", so can be controlled the degrees of expansion of rawhide by moisturizing number of times, rate of water make-up.

Facts have proved, the method of leather ash alkali unhairing is adopted to produce Cattlehide Full Grain Garment Leather, not only can save sodium sulphite 35% ~ 40%, greatly alleviate the pollution of sodium sulphite to environment, and rawhide expands even, abundant, appropriate, gained finished leather is soft, plentiful, good springiness, and loose side rate is low, utilization ratio is high.

Research shows, in liming bath, add a certain amount of auxiliary liming agent be conducive to collegen filament and relax, evenly and to be fully separated and loose, the liming time can be shortened, reduce collagen loss, overcome swelling that traditional liming technique easily causes, ash wrinkle (growth trace) obviously and the defect such as limiting material infiltration difference.The kind of auxiliary liming agent is a lot, and different types of auxiliary liming agent has different functions, can need to select according to technique.

In order to realize the unlimited recycle in liming, the useless source of multiple ash, realize sodium sulphite, lime " zero release ", reduce the consumption of lime and sodium sulphite to greatest extent, " method of leather ash alkali unhairing " and liming, multiple grey waste liquid circulation are utilized coupling by the author, establish " three systemic circulations " combined system.

New system after improvement absorbs the strong point that liming-multiple grey waste liquid circulation utilizes technology, meanwhile, also embodies the effect of traditional technology to a great extent, has acted on the old maxim of " good skin goes out at grey cylinder ".What is more important, this combination and coupling achieve the recycle of liming-multiple grey waste liquid, have eradicated lime, sodium sulphite to the pollution of environment.According to this system cloud gray model, first band hair rawhide enters liming bath (newly ash), bathes less after the depilation of grey alkaline process through modification, then enters multiple ash bath (always ash), unlike, the effect of multiple ash is strengthened to some extent.Like this, materials with hide glue fibril can be made really to obtain fully, be moderately separated and loose.No matter be liming bath or multiple ash bath, its waste liquid all enters same storage pool.

Research shows, the technique after improvement, and gained finished leather is plentiful, soft, good springiness, and not loose side substantially, and its reason is, for a long time ash manipulation again, strengthens the hydrolytic action to mucoid in rawhide collagen, and collegen filament obtain being separated fully and loose.Because the effect of Ca (OH) 2 comparatively relaxes, thus this hydrolytic action to collagen is come to relax and evenly.The old lixivium of this hydrolytic action and different batches has and cushions synergistic result, be exactly to collegen filament slowly, gentle, the even hydrolytic action of exquisiteness, this is the important foundation of producing high-grade leather.

Claims

1. make a method for leather, comprise rawhide liming step and the multiple grey step of rawhide, it is characterized in that: the waste liquid that described rawhide liming step and the multiple grey step of rawhide produce enters in same storage pool.