阅读说明：本技术 一种新型环保鞣制工艺 (Novel environment-friendly tanning process ) 是由 耿振华 杨建平 吴立伟 吴昊 吴杰 刘少宾 耿倩 于 2021-08-14 设计创作，主要内容包括：本发明涉及皮革加工技术领域,提出了一种新型环保鞣制工艺,包括以下步骤：S1、向转鼓中的皮中加入水,加热升温后添加第一鞣制剂进行一次鞣制；S2、加入第二鞣制剂升温二次鞣制；S3、再加入金属盐进行三次鞣制；其中所述第一鞣制剂为质量比为4-5:1的N-羟基丁二酰亚胺、(2-氧代-1,3-噁唑烷-3-基)乙酸的混合物；所述金属盐为质量比为2:1的氯化锆、氯化铝混合物。通过上述技术方案,解决了现有技术中鞣制工艺无法做到环保性和皮革性能兼顾的问题。(The invention relates to the technical field of leather processing, and provides a novel environment-friendly tanning process, which comprises the following steps: s1, adding water into the leather in the rotary drum, heating and raising the temperature, and then adding a first tanning agent for primary tanning; s2, adding a second tanning agent, heating and tanning for the second time; s3, adding metal salt to perform three times of tanning; wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4-5: 1; the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1. Through the technical scheme, the problem that the tanning process in the prior art cannot realize both environmental protection and leather performance is solved.)

1. A novel environment-friendly tanning process is characterized by comprising the following steps:

s1, adding water into the leather in the rotary drum, heating and raising the temperature, and then adding a first tanning agent for primary tanning;

s2, adding a second tanning agent, heating and tanning for the second time;

s3, adding metal salt to perform three times of tanning;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4-5: 1;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

2. A novel environmentally friendly tanning process according to claim 1, characterized in that said second tanning agent comprises 5-9 parts diaminoglyoxaloxime, 8-14 parts hydroxypropanedialdehyde, 12-16 parts N-ethylpyrrolidone, 2-5 parts alkyldimethylsulfopropyl betaine.

3. The novel environmentally friendly tanning process as claimed in claim 1, characterized in that in said step S1, water is added in an amount of 1.1-1.3 times the mass of the skins.

4. A novel environment-friendly tanning process as claimed in claim 1, wherein in step S1, heating to 38-40 ℃ and tanning for 40-60 min.

5. A novel environmentally friendly tanning process according to claim 1, characterized in that the mass of the first tanning agent is 5-8% of the mass of water.

6. A novel environmentally friendly tanning process according to claim 2, characterized in that the mass of said second tanning agent is 16-20% of the mass of water.

7. A novel environment-friendly tanning process as claimed in claim 1, wherein in step S2, temperature is raised to 42-44 ℃, and secondary tanning is carried out for 60-90 min.

8. The novel environmentally friendly tanning process according to claim 1, characterized in that in step S3, the mass of metal salt is 3% -5% of the mass of water.

9. A novel environmentally friendly tanning process according to claim 1, characterized in that in step S3, the tertiary tanning is a heat-insulated tanning for 5-6 h.

10. Leather obtained by neutralizing and fatliquoring leather tanned by the novel environment-friendly tanning process according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of leather processing, in particular to a novel environment-friendly tanning process.

Background

With the rapid development of economy, the leather industry in China has become the world center for leather processing and trade, and the leather industry has also become the mainstay of the light industry in China.

In the tanning process, the raw leather is subjected to 30-50 working procedures, wherein the tanning process is the key of raw leather tanning, and the basic raw material added in the tanning process is a tanning agent. Since the chrome tanning method of 19 century fifties appeared, the chrome tanning agent mainly containing trivalent chromium salt endows the leather with excellent comprehensive performance, high wet heat resistance stability, good bending resistance and the like, and is an effect which is difficult to achieve by any single tanning agent at present. The tanning technology has been dominated for hundreds of years, but the absorption rate of chromium in the traditional chromium tanning method is not high, and the environmental pressure of chromium-containing waste treatment still exists. Therefore, the research and development of environment-friendly chrome-free tanning materials and technologies become a main way for effectively solving the chrome tanning environmental problem from the source.

The non-chrome metal tanning agent and the aluminum tanning agent are used for tanning raw materials, but the aluminum tanning agent has poor performance when being used alone, so that the shrinkage temperature is low, the aluminum tanning agent is not resistant to water washing, the further development of the aluminum tanning agent in the field of leather tanning agents is limited, the aluminum tanning agent is difficult to replace a chrome tanning agent, and the aluminum tanning agent can only be used in certain specific fields.

Disclosure of Invention

The invention provides a novel environment-friendly tanning process, which solves the problem that the tanning process in the prior art cannot realize both environment friendliness and leather performance.

The technical scheme of the invention is as follows:

a novel environment-friendly tanning process comprises the following steps:

s1, adding water into the leather in the rotary drum, heating and raising the temperature, and then adding a first tanning agent for primary tanning;

s2, adding a second tanning agent, heating and tanning for the second time;

s3, adding metal salt to perform three times of tanning;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4-5: 1;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

As a further technical scheme, the second tanning agent comprises 5-9 parts of diaminoglyoxal oxime, 8-14 parts of hydroxypropanedialdehyde, 12-16 parts of N-ethylpyrrolidone and 2-5 parts of alkyl dimethyl sulfopropyl betaine.

As a further technical scheme, the second tanning agent also comprises 7-9 parts of N-trimethylsilyl-bis (trifluoromethanesulfonic acid) imide.

As a further technical scheme, in the step S1, water with the mass of 1.1-1.3 times of that of the peel is added.

As a further technical proposal, in the step S1, the temperature is raised to 38-40 ℃, the tanning is carried out for 40-60min,

as a further technical scheme, the mass of the first tanning agent is 5-8% of the mass of water.

As a further technical scheme, the mass of the second tanning agent is 16-20% of the mass of water

As a further technical scheme, in the step S2, the temperature is raised to 42-44 ℃, and the secondary tanning is carried out for 60-90 min.

As a further technical proposal, in the step S3, the mass of the metal salt is 3-5% of the mass of the water.

As a further technical scheme, in the step S3, the third tanning is heat-preservation tanning for 5-6 h.

The invention also provides leather obtained by performing neutralization and fat-liquoring post-treatment on the leather obtained by tanning according to the novel environment-friendly tanning process.

The invention has the beneficial effects that:

1. the invention adopts special tanning agent and limits the specific tanning process and tanning temperature according to the properties of the tanning agent, the shrinkage temperature of the prepared leather can reach 94-86 ℃, the tearing strength is about 104-109N/mm, and the tensile strength is 26-31N/mm²About 505 broken strength and about 527N/mm, and has excellent thermal stability and strength.

2. In the invention, (2-oxo-1, 3-oxazolidin-3-yl) acetic acid is adopted to replace the conventional oxazolidin, and more active functional groups are combined with active groups in collagen, so that the leather performance is improved. The addition of (2-oxo-1, 3-oxazolidin-3-yl) acetic acid may also improve the problem of poor shrink properties of aluminum tanning preparations. And (2-oxo-1, 3-oxazolidin-3-yl) acetic acid is better than oxazolidin in stability, but the inventor adds N-ethyl pyrrolidone in the second tanning agent in order to improve the stability, and finds that only N-ethyl pyrrolidone can improve the stability through experimental research.

3. The hydroxyl malondialdehyde is added, so that the function of glutaraldehyde can be exerted, and hydroxyl can be introduced to form covalent bonds with amino groups and imidazolyl groups in collagen, so that the flexibility and the strength are improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any inventive step, are intended to be within the scope of the present invention.

Example 1

S1, adding the degreased hide into a rotary drum, adding water which is 1.2 times of the hide by mass, heating to 38-40 ℃, and adding a first tanning agent which is 6% of the water by mass for primary tanning for 50 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4.5: 1;

s2, adding a second tanning agent accounting for 18% of the mass of water, heating to 42-44 ℃, and tanning for the second time for 80 min;

wherein the second tanning agent is 7 parts of diaminoglyoxal oxime, 11 parts of hydroxypropanedialdehyde, 14 parts of N-ethyl pyrrolidone and 4 parts of alkyl dimethyl sulfopropyl betaine;

s3, adding metal salt accounting for 4% of the mass of water, and keeping the temperature and tanning for 5.5 hours;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S4, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Example 2

S1, adding the degreased hide into a rotary drum, adding water which is 1.1 times of the hide by mass, heating to 38-40 ℃, and adding a first tanning agent which is 5% of the water by mass for primary tanning for 40 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 5: 1;

s2, adding a second tanning agent accounting for 20% of the mass of water, heating to 42-44 ℃, and tanning for 90min for the second time;

wherein the second tanning agent is 5 parts of diaminoglyoxal oxime, 8 parts of hydroxypropanedialdehyde, 12 parts of N-ethyl pyrrolidone and 2 parts of alkyl dimethyl sulfopropyl betaine;

s3, adding metal salt accounting for 3% of the mass of water, and performing heat preservation and tanning for 6 hours;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S4, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Example 3

S1, adding the degreased hide into a rotary drum, adding water which is 1.3 times of the hide by mass, heating to 38-40 ℃, and adding a first tanning agent which is 8% of the water by mass for primary tanning for 60 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4: 1;

s2, adding a second tanning agent accounting for 16 percent of the mass of water, heating to 42-44 ℃, and tanning for 60min for the second time;

wherein the second tanning agent is 9 parts of diaminoglyoxal oxime, 14 parts of hydroxypropanal, 16 parts of N-ethyl pyrrolidone and 5 parts of alkyl dimethyl sulfopropyl betaine;

s3, adding metal salt accounting for 5% of the mass of water, and performing heat preservation and tanning for 5 hours;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S4, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Example 4

S1, adding the degreased hide into a rotary drum, adding water which is 1.1 times of the hide by mass, heating to 38-40 ℃, and adding a first tanning agent which is 6% of the water by mass for primary tanning for 50 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 5: 1;

s2, adding a second tanning agent accounting for 18% of the mass of water, heating to 42-44 ℃, and tanning for the second time for 80 min;

wherein the second tanning agent is 8 parts of diaminoglyoxal oxime, 12 parts of hydroxypropanal, 15 parts of N-ethyl pyrrolidone and 3 parts of alkyl dimethyl sulfopropyl betaine;

s3, adding metal salt accounting for 4% of the mass of water, and keeping the temperature and tanning for 5.5 hours;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S4, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Example 5

S1, adding the degreased hide into a rotary drum, adding water which is 1.2 times of the hide by mass, heating to 38-40 ℃, and adding a first tanning agent which is 6% of the water by mass for primary tanning for 50 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4.5: 1;

s2, adding a second tanning agent accounting for 18% of the mass of water, heating to 42-44 ℃, and tanning for the second time for 80 min;

wherein the second tanning agent is 7 parts of diaminoglyoxal oxime, 11 parts of hydroxypropanedialdehyde, 14 parts of N-ethylpyrrolidone, 4 parts of alkyl dimethyl sulfopropyl betaine and 7 parts of N-trimethylsilyl-bis (trifluoromethanesulfonic acid) imide;

s3, adding metal salt accounting for 4% of the mass of water, and keeping the temperature and tanning for 5.5 hours;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S4, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Example 6

S1, adding the degreased hide into a rotary drum, adding water which is 1.1 times of the hide by mass, heating to 38-40 ℃, and adding a first tanning agent which is 6% of the water by mass for primary tanning for 50 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 5: 1;

s2, adding a second tanning agent accounting for 18% of the mass of water, heating to 42-44 ℃, and tanning for the second time for 80 min;

wherein the second tanning agent is 8 parts of diaminoglyoxal oxime, 12 parts of hydroxypropanedialdehyde, 15 parts of N-ethylpyrrolidone, 3 parts of alkyl dimethyl sulfopropyl betaine and 9 parts of N-trimethylsilyl-bis (trifluoromethanesulfonic acid) imide;

s3, adding metal salt accounting for 4% of the mass of water, and keeping the temperature and tanning for 5.5 hours;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S4, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Comparative example 1

In comparison to example 1, (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in the first tanning agent was replaced with an equal amount of oxazolidin.

Comparative example 2

In comparison to example 1, the hydroxypropanal in the second tanning agent was replaced by an equal amount of glutaraldehyde.

Comparative example 3

Compared with the example 1, the primary tanning temperature is 43-45 ℃, and the secondary tanning temperature is 46-47 ℃.

Comparative example 4

S1, adding the degreased hide into a rotary drum, adding water which is 1.2 times of the hide in mass, heating to 38-40 ℃, adding a first tanning agent which is 6% of the water in mass, a second tanning agent which is 18% of the water in mass and a metal salt which is 4% of the water in mass, heating to 42-44 ℃, and tanning for 460 min;

wherein the first tanning agent is a mixture of N-hydroxysuccinimide and (2-oxo-1, 3-oxazolidin-3-yl) acetic acid in a mass ratio of 4.5: 1;

wherein the second tanning agent is 7 parts of diaminoglyoxal oxime, 11 parts of hydroxypropanedialdehyde, 14 parts of N-ethyl pyrrolidone and 4 parts of alkyl dimethyl sulfopropyl betaine;

the metal salt is a mixture of zirconium chloride and aluminum chloride in a mass ratio of 2: 1.

S2, neutralizing, dyeing and fatliquoring the tanned leather to obtain the leather.

Comparative example 5

The N-ethylpyrrolidone from example 1 was replaced by 4-pyrimidone.

The above-mentioned specific implementation method is the same and conventional method for other process steps of leather processing except for specific description, and is not described more herein.

The leather prepared by the method is tested for shrinkage temperature and tensile strength according to QB/T2713-2005 and QB/T2710-2005, and the test results are shown in Table 1. According to the national standard GB/T2711-2005, the tearing force of the physical and mechanical test of leather is measured: double-edge tearing & lt & gt measures the tearing strength of leather; according to the national standard GB/T2712-2005, the method for measuring the grain surface strength and the stretching height of the leather in physical and mechanical tests comprises the following steps: the spherical bursting test measures the bursting strength of the leather.

TABLE 1 leather Performance test results for examples 1-6 and comparative examples 1-5

Method of implementation	Whether it is soft or not	Shrinkage temperature (. degree.C.)	Tear Strength (N/mm)	Tensile Strength (N/mm)2)	Bursting Strength (N/mm)
						Example 1	Is that	96	108.69	28.68	514.24
Example 2	Is that	95	104.84	27.45	505.87
						Example 3	Is that	94	106.47	26.97	510.85
Example 4	Is that	95	107.35	28.41	512.15
						Example 5	Is that	96	110.36	29.89	526.84
Example 6	Is that	94	112.68	30.24	521.64
						Comparative example 1	Is that	83	89.10	20.62	481.51
Comparative example 2	Is that	86	92.65	22.34	477.36
						Comparative example 3	Is that	80	86.12	19.64	459.47
Comparative example 4	Is that	88	94.25	23.47	481.45
						Comparative example 5	Is that	82	91.64	24.45	489.28

As can be seen from the data in Table 1, compared with comparative examples 1-4, the leather shrinkage temperature of the invention is reasonable 1-6, which can reach 94-86 ℃, the tear strength is 104-²The cracking strength is 505-.

In examples 5 and 6 of the present invention, N-trimethylsilyl-bis (trifluoromethanesulfonic acid) imide was also added to the second tanning agent, and the obtained leather has good overall performance, and on one hand, it is possible to improve the compatibility between other components in the tanning agent and the hide and to promote the absorption of the tanning agent, and on the other hand, the presence of active groups can also improve the leather strength.

In comparative example 1, in which (2-oxo-1, 3-oxazolidin-3-yl) acetic acid is replaced with an equal amount of oxazolidin, the stability and strength of leather are reduced, and the inventors believe that (2-oxo-1, 3-oxazolidin-3-yl) acetic acid improves leather performance by binding more active functional groups to active groups in collagen than conventional oxazolidines. The addition of (2-oxo-1, 3-oxazolidin-3-yl) acetic acid may also improve the problem of poor shrink properties of aluminum tanning preparations. (2-oxo-1, 3-oxazolidin-3-yl) acetic acid is more stable than oxazolidin, but the inventors added N-ethylpyrrolidone to improve its stability, and when in comparative example 5, other ketones were used instead of N-ethylpyrrolidone, the resulting leather was inferior in performance to the examples of the present application.

In comparative example 2, the improvement of leather properties was reduced when the hydroxy-malondialdehyde was replaced with glutaraldehyde, and the inventors believe that this was because the hydroxy-malondialdehyde not only acted as glutaraldehyde, but also introduced hydroxyl groups that could form covalent bonds with amino and imidazolyl groups in collagen, improving flexibility and strength.

In comparative examples 3 and 5, the tanning temperature is higher, the preparation process adopts a one-step method, and the effect is not the same as that of the embodiment of the invention. Because the tanning agent of the invention is special, the temperature needs to be strictly controlled, otherwise, the stability of the tanning agent is affected by overhigh temperature, and the problem of uneven dispersion can be caused if a one-step tanning method is adopted.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.