阅读说明：本技术 一种低甲醛低铬的环保型箱包革生产方法 (Production method of low-formaldehyde low-chromium environment-friendly luggage leather ) 是由 陈永榜 王小卓 姚庆达 李银生 胡杰 但卫华 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种低甲醛低铬的环保型箱包革生产方法,包括将浸酸皮组批、称重→鞣前富氨→鞣制→中和→鞣后富氨→复鞣→填充加脂；本申请的鞣前富氨、鞣后富氨中均含有多元胺,多元胺中的氨基一方面可以与皮胶原纤维上的活性羧基反应,增加胶原纤维上氨基的含量,进而可以与皮胶原纤维间因皮化原料引入的甲醛反应,生成稳定的亚胺结构,起到降低坯革中甲醛含量的作用；另一方面,还可以以此为活性位点,引入羧基结构,氨基与羧基都可以与金属离子产生鳌合作用,起到固定鞣剂分子的作用。(The invention discloses a production method of low-formaldehyde and low-chromium environment-friendly luggage leather, which comprises the steps of batching pickled leather, weighing → enriching ammonia before tanning → neutralizing → enriching ammonia after tanning → retanning → filling and fatliquoring; the ammonia-rich leather tanning agent contains polyamine before tanning and the ammonia-rich leather tanning, and on one hand, amino in the polyamine can react with active carboxyl on leather collagen fibers to increase the content of the amino on the collagen fibers, so that the polyamine can react with formaldehyde introduced by leather raw materials among the leather collagen fibers to generate a stable imine structure, and the effect of reducing the content of the formaldehyde in crust leather is achieved; on the other hand, the active site can be used for introducing a carboxyl structure, and both amino and carboxyl can generate a chelating effect with metal ions to play a role in fixing tanning agent molecules.)

1. The production method of the low-formaldehyde and low-chromium environment-friendly luggage leather is characterized by comprising the steps of batching pickled leather, weighing → enriching ammonia before tanning → neutralizing → enriching ammonia after tanning → retanning → filling and fatliquoring.

2. The production method of the environment-friendly luggage leather with low formaldehyde and low chromium according to claim 1, characterized in that the ammonia-rich process before tanning comprises the following specific steps: adding polyamine 0.5-2.0 wt% and polycarboxylic acid 0.1-0.5 wt% into the pickled leather drum for mechanical action.

3. The production method of the environment-friendly luggage leather with low formaldehyde and low chromium according to claim 1, characterized in that the ammonia-rich process after tanning is as follows: adding 1.5-3.5% of polycarboxylic acid and 2-4.5% of polyamine into a rotary drum based on the weight of the wet blue leather, and mechanically acting.

4. The production method of the low-formaldehyde low-chromium environment-friendly luggage leather as claimed in claim 2, wherein the ammonia-rich process before tanning comprises the following specific steps: adding 0.1-0.5% of polycarboxylic acid and 0.2-0.5% of polyamine into a rotating drum after pickling for 30-45 minutes according to the mass of the grey sheet; then 0.1-0.5% polyamine is added, and the mechanical action is carried out for 10-15 minutes; adding 0.1-0.5% polyamine, mechanically acting for 10-15 min, and finally adding 0.1-0.5% polyamine, mechanically acting for 10-15 min.

5. The production method of the environment-friendly luggage leather with low formaldehyde and low chromium according to claim 3, characterized in that the ammonia-rich process after tanning comprises the following specific steps: adding 100-300% of water, 1-2% of polycarboxylic acid and 1-2.5% of polyamine into a rotary drum, and mechanically acting for 20-40 minutes; then 0.5-1.0% of polyamine is added, and the mechanical action is carried out for 10-20 minutes; adding 0.5-1.0% polyamine, and mechanically acting for 10-20 min; finally, 0.5 to 1.5 percent of polycarboxylic acid is added, and the mechanical action is carried out for 20 to 40 minutes.

6. The method for producing environment-friendly luggage leather with low formaldehyde and low chromium according to claim 1, characterized in that the tanning agent in the tanning and retanning procedures at least contains any one of zirconium, aluminum, iron, titanium and silicon.

7. The method for producing the environment-friendly luggage leather with low formaldehyde and low chromium according to any one of claims 2 to 5, wherein the polyamine is at least one of ethylenediamine, triethylamine, 1, 2-dinitrophenylhydrazine, 2, 4-dinitrophenylhydrazine, hydrazine, semicarbazide and ethyleneurea.

8. The method for producing environment-friendly luggage leather with low formaldehyde and low chromium according to any one of claims 2 to 5, wherein the polycarboxylic acid is at least one of oxalic acid, citric acid, ethylenediamine tetraacetic acid, lactic acid and boric acid.

Technical Field

The invention relates to the field of leather making, in particular to a production method of environment-friendly luggage leather with low formaldehyde and low chromium.

Background

The current dilemma which troubles the development of the luggage leather towards environment protection mainly comprises two steps, firstly, the utilization rate of the chrome tanning agent is low and is only 60-70% in the production process of the luggage leather, and the pressure of the ecological environment can be increased by chrome-containing waste water, sludge and waste leather scraps produced after tanning. Secondly, along with the enhancement of the environmental protection consciousness and the green consumption consciousness of people, a series of standards are established for the limit of formaldehyde in leather products in many countries. In order to avoid the harm of chromium and formaldehyde in leather products to human bodies and the technical barrier problem in import and export, the contents of chromium and formaldehyde in the leather products need to be strictly controlled.

In the prior art, a few chromium tanning processes and a small amount of chromium-free metal tanning agents are generally adopted to replace chromium tanning agents, the risk of extraction of chromium still exists, and metal extraction of the chromium-free metal tanning agents is possible. The physical and mechanical properties, thermal stability and storage performance of the chrome-free organic tanned finished leather are extremely poor and are difficult to meet the requirements of relevant standards, so that the development of a chrome-free metal tanning related process and the improvement of the absorption rate of a chrome-free metal tanning agent are urgently needed; at present, a large amount of protein filler is often added into leather to adsorb free formaldehyde, but the excessive protein filler can reduce the physical and mechanical properties of finished leather, and meanwhile, the risk that the finished leather is easy to grow bacteria and mildew exists.

Disclosure of Invention

The embodiment of the application provides a production method of low-formaldehyde and low-chromium environment-friendly luggage leather, which comprises the steps of batching pickled leather, weighing → enriching ammonia before tanning → neutralizing → enriching ammonia after tanning → retanning → filling and fatliquoring.

Further, the ammonia-rich process step before tanning comprises the following specific steps: adding polyamine 0.5-2.0 wt% and polycarboxylic acid 0.1-0.5 wt% into the pickled leather drum for mechanical action.

Further, the post-tanning ammonia-rich process comprises the following steps: adding 1.5-3.5% of polycarboxylic acid and 2-4.5% of polyamine into a rotary drum based on the weight of the wet blue leather, and mechanically acting.

Further, the ammonia-rich process step before tanning comprises the following specific steps: adding 0.1-0.5% of polycarboxylic acid and 0.2-0.5% of polyamine into a rotating drum after pickling for 30-45 minutes according to the mass of the grey sheet; then 0.1-0.5% polyamine is added, and the mechanical action is carried out for 10-15 minutes; adding 0.1-0.5% polyamine, mechanically acting for 10-15 min, and finally adding 0.1-0.5% polyamine, mechanically acting for 10-15 min.

Further, the specific steps of the post-tanning ammonia-rich process are as follows: adding 100-300% of water, 1-2% of polycarboxylic acid and 1-2.5% of polyamine into a rotary drum, and mechanically acting for 20-40 minutes; then 0.5-1.0% of polyamine is added, and the mechanical action is carried out for 10-20 minutes; adding 0.5-1.0% polyamine, and mechanically acting for 10-20 min; finally, 0.5 to 1.5 percent of polycarboxylic acid is added, and the mechanical action is carried out for 20 to 40 minutes.

Furthermore, the tanning agent in the tanning and retanning procedures at least contains any one of zirconium, aluminum, iron, titanium and silicon.

Further, the polyamine is at least one of ethylenediamine, triethylamine, 1, 2-dinitrophenylhydrazine, hydrazine, semicarbazide and ethyleneurea.

Further, the polycarboxylic acid is at least one of oxalic acid, citric acid, ethylene diamine tetraacetic acid, lactic acid and boric acid.

One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

the ammonia-rich leather tanning agent contains polyamine before tanning and the ammonia-rich leather tanning, and on one hand, amino in the polyamine can react with active carboxyl on leather collagen fibers to increase the content of the amino on the collagen fibers, so that the polyamine can react with formaldehyde introduced by leather raw materials among the leather collagen fibers to generate a stable imine structure, and the effect of reducing the content of the formaldehyde in crust leather is achieved; on the other hand, the active site can be used for introducing a carboxyl structure, and both amino and carboxyl can generate a chelating effect with metal ions to play a role in fixing tanning agent molecules.

The polyamine in the ammonia-rich before tanning and the polyamine in the ammonia-rich after tanning can generate synergistic action with the polycarboxylic acid, functional structures such as imino, phenyl and the like can also exist on chain segments of the polyamine and the polycarboxylic acid, and the structures can enhance the compatibility of leather collagen fibers and leather chemicals such as acrylic resin, amino resin, protein filler, polyphenol tanning agents (such as synthetic tanning agent and tannin extract) and further improve the comprehensive performance of crust leather.

Detailed Description

In order to better understand the technical solutions, the technical solutions will be described in detail with reference to the description and the specific embodiments.

Example 1:

a production method of environment-friendly luggage leather with low formaldehyde and low chromium comprises the following steps:

1) batching and weighing pickled skins

2) Rich in ammonia before tanning

Adding 0.3% of citric acid and 0.2% of ethylenediamine into the pickled rotary drum, and mechanically acting for 30 minutes; then adding 0.1 percent of 2, 4-dinitrophenylhydrazine, and mechanically acting for 15 minutes; then 0.1% of 2, 4-dinitrophenylhydrazine is added for mechanical action for 15 minutes, and finally 0.1% of ethylenediamine is added for mechanical action for 15 minutes.

3) Tanning

Adding 0.3% of modified aldehyde tanning agent (GTW, Basf chemical industry) and 0.5% of sodium formate based on the mass of pickled leather, rotating for 30 minutes, then adding 8% of zirconium aluminum tanning agent (TWLZ, Tingjiang chemical industry) twice, rotating for 240 minutes, stopping the drum for overnight, adding 0.3% of modified aldehyde tanning agent (GTW, Basf chemical industry) and 0.5% of sodium formate the next day, rotating for 20 minutes, then adding 1.0% of ammonium bicarbonate for 2 times, rotating for 60 minutes, adding 100% of water, adjusting the temperature to 40 ℃, rotating for 180 minutes, stopping the drum for overnight, and draining to obtain the wet white leather.

4) Neutralization

Based on the weight of the wet white leather, 100% of water and 0.2% of formic acid are added into a rotating drum filled with the wet white leather, the rotating drum is rotated for 20 minutes, then 2% of synthetic tannin (FBV, Yixiang chemical company), 1% of ammonium bicarbonate and 1% of sodium formate are added, the rotating drum is rotated for 20 minutes, finally 0.4% of ammonium bicarbonate is added, and water is drained after the rotating drum is rotated for 40 minutes.

5) Rich in ammonia after tanning

Adding 150% of water, 2% of citric acid and 2% of ethylenediamine into a rotary drum, and mechanically acting for 30 minutes; then adding 0.5 percent of 2, 4-dinitrophenylhydrazine, and mechanically acting for 20 minutes; then 0.5 percent of 2, 4-dinitrophenylhydrazine is added, and the mechanical action is carried out for 20 minutes; finally, 0.5% of ethylenediamine tetraacetic acid is added, and the mechanical action is carried out for 20 minutes.

6) Retanning, filling and fatliquoring

Adding 150% of water into a rotary drum, controlling the temperature to be 35 ℃, adding 4% of zirconium-aluminum tanning agent (TWLZ, Tingjiang chemical industry), rotating for 120 minutes, then adding 10% of acrylic resin (RV, Passion chemical industry), 3% of maleic anhydride-styrene copolymer (EMS, Zhiqi trade), 2% of amino resin (DLF, Passion chemical industry), rotating for 120 minutes, adding chestnut tannin extract (C-C, Starer dye) and modified animal protein (PC, Desel chemical industry), and rotating for 120 minutes. The temperature is raised to 52 ℃, 10 percent of synthetic grease (BSFR, Sch i l Sei l acher) and 5 percent of phosphate fatliquoring agent (BA, sima chemical industry) are added, and the mixture is rotated for 120 minutes. Adding 1% formic acid, adding in three times, rotating for 40 minutes, and draining.

Comparative example 1

A production method of environment-friendly luggage leather with low formaldehyde and low chromium comprises the following steps:

comparative example 1 the production process was largely the same as that of example 1, except that comparative example 1 did not have a pre-tanning ammonia enrichment and a post-tanning ammonia enrichment step.

The experimental tests of example 1 and comparative example 1 were carried out, and the obtained experimental data are shown in table 1:

TABLE 1

The above description is only an embodiment utilizing the technical content of the present disclosure, and any modification and variation made by those skilled in the art can be covered by the claims of the present disclosure, and not limited to the embodiments disclosed.