阅读说明：本技术 一种适合高级皮革的环保型复鞣剂的制备方法 (Preparation method of environment-friendly retanning agent suitable for high-grade leather ) 是由 周忠达 周妮频 于 2020-11-19 设计创作，主要内容包括：本发明公开了一种适合高级皮革的环保型复鞣剂的制备方法,将一定量的淀粉、酶和水投入反应釜中糊化,搅拌,在一定温度下进行酶解,然后在设定温度下恒速滴加入含有一定量的引发剂水溶液的反应釜中,同时恒速滴加一定量的丙烯酸钠和水的混合物,同时滴加一定量的调节剂,两者滴加一定时间后,滴加一定浓度的引发剂,滴加结束后,在一定温度下保温反应,然后冷却至一定温度以下,用氢氧化钠调节pH,产品有效含量在30～34％,粘度为4000～6000cps。本发明中采用普鲁兰酶与耐高温a-淀粉酶相互配合,可以有效提升复鞣剂的应用效果；本发明环境友好,鞣制皮革具有优秀的手感、光滑的表面和良好的柔性和韧性,适合于鞣制高档皮革。(The invention discloses a preparation method of an environment-friendly retanning agent suitable for high-grade leather, which comprises the steps of putting a certain amount of starch, enzyme and water into a reaction kettle for gelatinization, stirring, carrying out enzymolysis at a certain temperature, then dropwise adding into the reaction kettle containing a certain amount of initiator aqueous solution at a constant speed at a set temperature, dropwise adding a certain amount of mixture of sodium acrylate and water at a constant speed, dropwise adding a certain amount of regulator, dropwise adding the initiator with a certain concentration after a certain time, carrying out heat preservation reaction at a certain temperature after dropwise adding, cooling to a certain temperature, and adjusting the pH with sodium hydroxide, wherein the effective content of a product is 30-34%, and the viscosity is 4000-6000 cps. According to the invention, pullulanase and high-temperature-resistant a-amylase are matched with each other, so that the application effect of the retanning agent can be effectively improved; the invention is environment-friendly, and the tanned leather has excellent hand feeling, smooth surface and good flexibility and toughness, and is suitable for tanning high-grade leather.)

1. The preparation method of the environment-friendly retanning agent suitable for the high-grade leather is characterized by comprising the following steps of:

step one, preparing solution A: mixing starch and pure water in proportion, gelatinizing at 80-120 ℃ for 30-90 minutes, cooling to 55-65 ℃, adding 4-10 units of mixed enzyme per gram of starch under stirring, and performing enzymolysis for 20-60 minutes to obtain a transparent solution A;

step two, preparing a solution B: placing acrylic acid in a reaction kettle, cooling and stirring, and dropwise adding liquid caustic soda at the reaction temperature of 0-40 ℃ to obtain a solution B;

step three, preparing a solution C: dissolving a regulator in pure water, wherein the concentration of the regulator is 3% -42%, so as to obtain a solution C;

step four, preparing a solution D: dropping initiator and pure water to prepare solution D with concentration of 2-3.5%;

step five, reaction: the bottom materials of the reaction kettle are initiator and pure water, and the concentration of the initiator is 1-2 per mill; heating the temperature of the reaction kettle to 60-80 ℃, simultaneously dripping A, B, C solution, heating to 85-93 ℃, maintaining the reaction temperature, dripping A, B for 50-70 minutes, dripping C for 10-15 minutes before A, B solution, dripping D solution for 8-12 minutes after A, B, C dripping, finishing dripping A, B simultaneously, continuing to react for 120-180 minutes at 85-93 ℃ after finishing dripping, cooling to below 50 ℃, dripping liquid alkali for neutralizing until the pH is 6-7, and the neutralization temperature is lower than 50 ℃, so as to obtain a product with the solid content of 30-34% and the viscosity of 4000-6000 cps;

the above concentrations are mass concentrations.

2. The method for preparing an environment-friendly retanning agent suitable for high-grade leather according to claim 1, wherein in the first step, the starch and the water are mixed according to a weight ratio of 0.2-0.3: mixing at a ratio of 1.

3. The method for preparing an environment-friendly retanning agent for advanced leather as claimed in claim 1, wherein in the first step, pullulanase accounts for 0.8-1.2% of the total weight of the mixed enzyme, and the rest is thermostable a-amylase.

4. The method for preparing the environment-friendly retanning agent suitable for the high-grade leather according to claim 1, wherein in the second step, the weight ratio of acrylic acid to 30-32% of liquid alkali is 72: 60 to 100.

5. The process for preparing environment friendly retanning agent for advanced leather as claimed in claim 1, wherein in the third step, the modifier is one or two of isopropanol and sodium metabisulfite.

6. The method for preparing environment-friendly retanning agent for high-grade leather as claimed in claim 1, wherein in the fourth step, the initiator is one or a combination of water-based peroxides.

7. The method of preparing an environment-friendly retanning agent for advanced leather as claimed in claim 6, wherein said initiator is ammonium persulfate or potassium persulfate.

8. The process for preparing an eco-friendly retanning agent for advanced leather as claimed in any one of claims 1 to 7, wherein said purified water is first reverse osmosis treated and then treated with a mixed bed or purified water having an electric conductivity of less than 5 μ s/cm.

9. The method for preparing an environment-friendly retanning agent suitable for high-grade leather according to claim 1, wherein in the fifth step, the weight ratio of the primer, the acrylic acid, the starch, the regulator solution and the dropping initiator solution is 0.5-0.6: 1: 0.8-0.85: 0.25-0.32: 0.2-0.25.

Technical Field

The invention relates to the technical field of leather auxiliaries, in particular to a preparation method of an environment-friendly retanning agent suitable for high-grade leather.

Background

Artificial synthetic leather tanning agents appeared as early as 1911, and technologies of synthetic tanning agents appeared in 1930 in Germany, and with the technological progress, four major types of synthetic resin tanning agents, aromatic tanning agents, aliphatic tanning agents and aldehyde and quinone tanning agents appear in sequence.

Retanning in the tanning production process is the 'gold spotting' process, and a retanning agent is an important leather auxiliary agent used in the retanning process, and the retanning method and the components of the retanning agent directly influence the color, quality, softness, fullness, elasticity, bleaching property and light fastness of leather. The active group, molecular weight and distribution of the retanning agent directly influence the filling property of leather fiber gaps and the change of the surface grain state of leather.

Acrylic retanning agents were novel retanning agents developed in the 60 s. Researches show that the acrylic retanning agent can permeate into gaps of leather fibers, has a selective filling effect, is a good chromium absorbent, can improve the quality and the position difference of leather, and endows the leather with better softness, fullness, mechanical properties and light resistance.

With the development of society, the requirements of people on leather are higher and higher, and the environmental protection of the leather making process is stricter and stricter, so that the development of high-quality and environment-friendly leather additives and even natural leather additives becomes a trend more and more.

Disclosure of Invention

Based on the technical problems in the prior art, the invention provides a preparation method of an environment-friendly retanning agent suitable for high-grade leather in order to overcome the defects of the prior art, improve the fullness, softness and mechanical properties of the leather and endow the leather with excellent hand feeling and smooth surface.

The technical scheme of the invention is as follows:

the preparation method of the environment-friendly retanning agent suitable for the high-grade leather comprises the following steps:

step one, preparing solution A: mixing starch and pure water in proportion, gelatinizing at 80-120 ℃ for 30-90 minutes, cooling to 55-65 ℃, adding 4-10 units of mixed enzyme per gram of starch under stirring, and performing enzymolysis for 20-60 minutes to obtain a transparent solution A;

step two, preparing a solution B: placing acrylic acid in a reaction kettle, cooling and stirring, and dropwise adding liquid caustic soda at the reaction temperature of 0-40 ℃ to obtain a solution B;

step three, preparing a solution C: dissolving a regulator in pure water, wherein the concentration of the regulator is 3% -42%, so as to obtain a solution C;

step four, preparing a solution D: dropping initiator and pure water to prepare solution D with concentration of 2-3.5%;

step five, reaction: the bottom materials of the reaction kettle are initiator and pure water, and the concentration of the initiator is 1-2 per mill; heating the temperature of the reaction kettle to 60-80 ℃, simultaneously dripping A, B, C solution, heating to 85-93 ℃, maintaining the reaction temperature, dripping A, B for 50-70 minutes, dripping C for 10-15 minutes before A, B solution, dripping D solution for 8-12 minutes after A, B, C dripping, finishing dripping A, B simultaneously, continuing to react for 120-180 minutes at 85-93 ℃ after finishing dripping, cooling to below 50 ℃, dripping liquid alkali for neutralizing until the pH is 6-7, and the neutralization temperature is lower than 50 ℃, so as to obtain a product with the solid content of 30-34% and the viscosity of 4000-6000 cps;

the above concentrations are mass concentrations.

Preferably, in the first step, the weight ratio of the starch to the water is 0.2-0.3: mixing at a ratio of 1.

Preferably, in the first step, pullulanase accounts for 0.8-1.2% of the total weight of the mixed enzyme, and the rest is high-temperature resistant a-amylase.

Preferably, in the second step, the weight ratio of acrylic acid to 30-32% of liquid caustic soda is 72: 60 to 100.

Preferably, in the third step, the regulator is one or a combination of two of isopropanol and sodium metabisulfite.

Preferably, in the fourth step, the initiator is one or a combination of several of aqueous peroxides.

Further preferably, the initiator is ammonium persulfate or potassium persulfate.

Preferably, the pure water is water subjected to first-stage reverse osmosis treatment and mixed bed treatment or pure water with the conductivity lower than 5 mu s/cm.

Preferably, the weight ratio of the base material, the acrylic acid, the starch, the regulator solution and the dropping initiator solution is 0.5-0.6: 1: 0.8-0.85: 0.25-0.32: 0.2-0.25.

The invention has the advantages that: the invention discloses a preparation method of an environment-friendly leather retanning agent, which comprises the steps of putting a certain amount of starch, enzyme and water into a reaction kettle for gelatinization, stirring, carrying out enzymolysis at a certain temperature, then dropwise adding the mixture of a certain amount of sodium acrylate and water into the reaction kettle containing a certain amount of initiator aqueous solution at a constant speed at a set temperature, dropwise adding a certain amount of regulator at the same time, dropwise adding the initiator with a certain concentration after dropwise adding the regulator for a certain time, carrying out heat preservation reaction at a certain temperature after dropwise adding, cooling to a certain temperature or below, and adjusting the pH with sodium hydroxide, wherein the effective content of a product is 30-34%, and the viscosity is 4000-6000 cps. According to the invention, pullulanase and high-temperature-resistant a-amylase are matched with each other, so that the application effect of the retanning agent can be effectively improved; the invention is environment-friendly, and the tanned leather has excellent hand feeling, smooth surface and good flexibility and toughness, and is suitable for tanning high-grade leather.

Detailed Description

Example 1

The preparation method of the environment-friendly retanning agent suitable for the high-grade leather comprises the following steps:

step one, preparing solution A: adding 150 g of water into 40 g of starch, stirring and heating for 60 minutes at 100 ℃, then cooling to 60 ℃, adding 300 units of high-temperature resistant alpha-amylase containing 1 percent of pullulanase, performing enzymolysis for 60 minutes, and then cooling.

Step two, preparing a solution B: 60 g of acrylic acid, and 60 g of 32.5% aqueous alkali is added to neutralize the acrylic acid at a temperature of below 30 ℃ while stirring.

Step three, preparing a solution C: 0.62 g of sodium metabisulfite and 7.42 g of isopropanol were weighed out and dissolved in 9.9 g of purified water for further use.

Step four, preparing a solution D: 0.36 g of potassium persulfate was weighed out and dissolved in 11.78 g of pure water for further use.

Step five, reaction: 0.0588 g of potassium persulfate and 32.6 g of pure water are added into a reaction kettle, the mixture is heated to 75 ℃, then A, B, C solution is dripped, the dripping is finished in 60 minutes, 60 minutes and 50 minutes respectively, after 10 minutes of the dripping is started, the dripping is started and is finished in 50 minutes, the dripping is finished after 10 minutes of A, B, C solution, the dripping is finished after 10 minutes of the D solution and is simultaneously dripped with A, B, the reaction temperature is kept at 90 ℃, after the dripping is finished, the reaction temperature is kept at 90 ℃ for reaction for 150 minutes, then the temperature is reduced to 35 ℃, 32% liquid alkali is used for adjusting the pH to be 6.3, the solid content of a product is 32%, and the viscosity is 4500 cps.

Examples 2,

Step one, preparing solution A: adding 150 g of water into 40 g of starch, stirring and heating for 60 minutes at 100 ℃, then cooling to 60 ℃, adding 300 units of high-temperature resistant alpha-amylase containing 1 percent of pullulanase, performing enzymolysis for 40 minutes, and then cooling.

Step two, preparing a solution B: 60 g of acrylic acid, and 65 g of 32% aqueous alkali was added thereto at a temperature of 30 ℃ or lower with stirring to neutralize the acrylic acid.

Step three, preparing a solution C: 0.62 g of sodium metabisulfite and 7.42 g of isopropanol were weighed out and dissolved in 9.9 g of purified water for further use.

Step four, preparing a solution D: 0.36 g of potassium persulfate was weighed out and dissolved in 11.78 g of pure water for further use.

Step five, reaction: 0.0588 g of potassium persulfate and 32.6 g of pure water are added into a reaction kettle, the mixture is heated to 75 ℃, then A, B, C solution is dropwise added after 60 minutes, 60 minutes and 50 minutes are respectively added, after 8 minutes of dropwise addition, C is dropwise added and the dropwise addition is completed in 50 minutes, D solution is dropwise added after 10 minutes of A, B, C and is simultaneously dropwise added with A, B, the reaction temperature is kept at 92 ℃, after the dropwise addition is completed, the reaction temperature is kept at 92 ℃ for reaction for 150 minutes, then the temperature is reduced to 35 ℃, 32% liquid alkali is used for adjusting the pH to 6.3, the solid content of a product is 32.5%, and the viscosity is 5500 cps.

Example 3

The preparation method of the environment-friendly retanning agent suitable for the high-grade leather comprises the following steps:

step one, preparing solution A: adding 150 g of water into 30 g of starch, stirring and heating for 30 min at 120 ℃, then cooling to 65 ℃, adding 300 units of high-temperature resistant alpha-amylase containing 0.8 percent of pullulanase, performing enzymolysis for 60 min, and then cooling.

Step two, preparing a solution B: 72 g of acrylic acid, 100 g of 32% strength aqueous alkali is added to neutralize them at a temperature below 30 ℃ with stirring.

Step three, preparing a solution C: 0.62 g of sodium metabisulfite and 7.42 g of isopropanol were weighed out and dissolved in 9.9 g of purified water for further use.

Step four, preparing a solution D: 0.36 g of potassium persulfate was weighed out and dissolved in 11.78 g of pure water for further use.

Step five, reaction: 0.0588 g of potassium persulfate and 32.6 g of pure water are added into a reaction kettle, the mixture is heated to 75 ℃, then A, B, C solution is dripped, the dripping is finished within 65 minutes, 65 minutes and 55 minutes respectively, after 10 minutes of the dripping is started, the dripping is started and is finished within 55 minutes, the solution D is dripped after 10 minutes of A, B, C dripping and is finished with A, B dripping simultaneously, the reaction temperature is kept at 85 ℃, after the dripping is finished, the reaction temperature is kept at 85 ℃ for reaction for 180 minutes, then the temperature is reduced to 35 ℃, 32% liquid alkali is used for adjusting the pH to 6.5, the solid content of a product is 31.7%, and the viscosity is 4080 cps.

Example 4

The preparation method of the environment-friendly retanning agent suitable for the high-grade leather comprises the following steps:

step one, preparing solution A: adding 150 g of water into 45 g of starch, stirring and heating for 90 minutes at 80 ℃, then cooling to 55 ℃, adding 300 units of high-temperature resistant alpha-amylase containing 1 percent of pullulanase, performing enzymolysis for 60 minutes, and then cooling.

Step two, preparing a solution B: 60 g of acrylic acid, and 55 g of 34% aqueous alkali at a temperature of 30 ℃ or lower with stirring.

Step three, preparing a solution C: 0.62 g of sodium metabisulfite and 7.42 g of isopropanol were weighed out and dissolved in 9.9 g of purified water for further use.

Step four, preparing a solution D: 0.36 g of potassium persulfate was weighed out and dissolved in 11.78 g of pure water for further use.

Step five, reaction: 0.0588 g of potassium persulfate and 32.6 g of pure water are added into a reaction kettle, the mixture is heated to 75 ℃, then A, B, C solution is dripped, the dripping is finished within 55 minutes, 55 minutes and 45 minutes respectively, after 10 minutes of the dripping is started, the dripping is started and is finished within 45 minutes, the dripping is finished 10 minutes after A, B, C solution is dripped, the dripping is finished simultaneously with A, B, the reaction temperature is kept at 93 ℃, after the dripping is finished, the reaction temperature is kept at 93 ℃ for 135 minutes, then the temperature is reduced to 35 ℃, 32% liquid alkali is used for adjusting the pH to 6.1, the solid content of the product is 32.2%, and the viscosity is 5210 cps.

Comparative example 1

The pullulanase in the example 1 is replaced by the horseradish peroxidase, and the rest proportion and the preparation method are not changed.

Comparative example 2

The pullulanase in the example 1 is replaced by the high-temperature resistant a-amylase, and the rest proportion and the preparation method are not changed.

Test example

Two commercial blue skins, 1.2mm thick, were washed with 3 times the weight of blue skin in 30 ℃ hot water, then washed in 3 times the weight of blue in 30 ℃ hot water with pH 4.5 adjusted with sodium formate and sodium carbonate, then retanned with 3% solids by the solution prepared in example 1 at 40 ℃ for 120 minutes, washed, then dyed with 1 times the amount of 1% stain (SELLA FAST Navy E from TFL Ledertechnik) at 50 ℃, fatliquored with 8% lecithin fatliquor with formic acid at pH 4.0, treated to give soft, smooth and bright leather suitable for high-grade leather.

The results of the following tests on the color strength and other properties of the retanning agents of examples 1-4 and comparative examples 1-2 on leather are shown in table 1.

Testing an instrument:

1. heat resistance: HT-1035 high temperature weatherometer;

2. light resistance: HE-UV8 leather UV ultraviolet aging test box;

3. color fastness: LFY-304 fabric rubbing color fastness tester;

4. fullness degree: the hand feeling test of the testers with rich experience is carried out;

5. flexibility: the hand feeling test of the testers with rich experience is carried out;

6. compactness: and testing the hand feeling of the testers with rich experience.

Table 1: results of application test of the retanning agents of examples 1 to 4 and comparative examples 1 to 2; the tests were classified into 5 grades, 1 being good, 2 being good, 3 being normal, 4 being poor and 5 being very poor.

	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2	Outsourcing product
								Heat resistance	1	1	1	1	2	3	3
Light resistance	2	2	2	2	3	3	3
								Color fastness	1	1	1	1	3	4	4
Fullness and fullness of skin	1	1	1	1	3	4	3
								Flexibility	1	1	1	1	2	3	3
Compactness of	1	1	1	1	3	3	3

According to the test data, the pullulanase and the high-temperature-resistant a-amylase are matched with each other, so that the application effect of the retanning agent can be effectively improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.