Preparation method and application of high absorption storage-resistant organic tanning auxiliary based on chrome-free tanning

Abstract

The application relates to a preparation method of a high-absorption storage-resistant organic tanning auxiliary based on chrome-free tanning, which comprises the following steps: uniformly mixing benzenehexacid and pentaerythritol, dropwise adding concentrated sulfuric acid, removing the excessive pentaerythritol through rotary evaporation, adjusting the pH value, and obtaining benzenehexacid-core pickling auxiliary; uniformly mixing pentaerythritol and benzenehexacid, dropwise adding concentrated sulfuric acid, removing the excessive benzenehexacid through rotary evaporation, adding pentaerythritol, uniformly mixing, dropwise adding concentrated sulfuric acid, keeping warm, reducing to room temperature, removing the excessive pentaerythritol through rotary evaporation, and adjusting the pH value, so as to obtain pentaerythritol-core tanning auxiliary. The benzenehexacid-core pickling auxiliary has strong cationicity, the pentaerythritol-core tanning auxiliary also has strong cationicity, and the cooperation of the two auxiliaries can obviously reduce the COD and BOD5 in waste liquid, and can also improve the shrinkage temperature and softness of white wet leather.

Description

TECHNICAL FIELD

[0001] The application relates to the field of tanning technology, in particular to a preparation method and application of a high-absorption and storage-resistant organic tanning auxiliary based on chrome-free tanning. BACKGROUND

[0002] At present, chrome-free tanned leather on the market can be divided into two types, namely, an anionic chrome-free tanning system taking an organic tanning agent as a core and a cationic chrome-free tanning system taking a chrome-free multi-metal tanning agent as a core. The chrome-free multi-metal tanning system has a similar cationic structure and cationic system as the chrome tanning system, and the charge of the skin collagen fiber is negative, so the chrome-free multi-metal tanning has good combination capacity with the skin collagen fiber. However, the organic tanning agent is anionic, and the charge of the skin collagen fiber is repulsive, and the organic tanning agent has no cationic center to combine with the skin collagen fiber, so the combination capacity of the organic tanning agent with the skin collagen fiber is extremely weak. The organic tanning agent is mainly squeezed into the gap between the skin collagen fibers by osmotic pressure, and then fixed in the skin collagen fibers by hydrogen bonds. However, the combination capacity of the method relying on hydrogen bonds is extremely weak, and the tanning is easily washed off. SUMMARY

[0003] The application provides a preparation method and application of a high-absorption and storage-resistant organic tanning auxiliary based on chrome-free tanning, to solve the problem of weak combination capacity of the organic tanning agent with the skin collagen fiber.

[0004] The application adopts the following technical scheme:

[0005] The preparation method of the high-absorption and storage-resistant organic tanning auxiliary based on chrome-free tanning comprises an acid immersion auxiliary taking benzenehexanoic acid as a core and a tanning auxiliary taking pentaerythritol as a core.

[0006] The preparation steps of the acid immersion auxiliary taking benzenehexanoic acid as a core are as follows: 100 parts of benzenehexanoic acid and 600-800 parts of pentaerythritol are uniformly mixed, the temperature is slowly increased to 180-200 DEG C under the protection of nitrogen, 5-20 parts of concentrated sulfuric acid is added drop by drop within 1 h, then the temperature is continuously kept for 1-5 h, the temperature is slowly reduced to room temperature, the excess pentaerythritol is removed by rotary evaporation, the reaction product is transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.0-1.5, and the acid immersion auxiliary taking benzenehexanoic acid as a core is obtained.

[0007] The preparation steps of the tanning aid with pentaerythritol as the core are as follows: 100 parts of pentaerythritol, 450-600 parts of benzene hexacid are uniformly mixed, under the protection of nitrogen, the temperature is slowly increased to 180-200 DEG C, 8-30 parts of concentrated sulfuric acid is added drop by drop within 1h, then the temperature is continuously kept for 1-5h, the temperature is slowly decreased to room temperature, then the excessive benzene hexacid is removed by rotary evaporation, the reactant is transferred into a flask, 1200-1800 parts of pentaerythritol is added, after being uniformly mixed, the temperature is slowly increased to 200-220 DEG C under the protection of nitrogen, 15-50 parts of concentrated sulfuric acid is added drop by drop within 1h, then the temperature is kept for 3-7h, the temperature is slowly decreased to room temperature, then the excessive pentaerythritol is removed by rotary evaporation, the reactant is transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.0-1.5, and the tanning aid with pentaerythritol as the core is obtained.

[0008] The application of a high-absorption storage-resistant organic tanning aid based on chrome-free tanning at least comprises an acid dipping process and a tanning process.

[0009] The specific steps of the acid dipping process are as follows: the temperature of the drum is controlled to be 20-25 DEG C according to the weight of the softened skin, 20-40% of water, 3-5% of salt, 0.2-0.5% of formic acid, 0.1-0.5% of the acid dipping aid with benzene hexacid as the core are added, the drum is rotated for 20 minutes, finally 1-1.5% of sulfuric acid and 0.2-0.6% of the acid dipping aid with benzene hexacid as the core are added, the drum is rotated for 5 minutes, and the process is stopped for 25 minutes, and the process is repeated for 4 times.

[0010] The specific steps of the tanning process are as follows: the temperature of the drum is controlled to be 25-30 DEG C according to the weight of the softened skin, 0.5-1% of the acid-resistant fatting agent is added, the drum is rotated for 15 minutes, 5-8% of the organic tanning agent is added, the drum is rotated for 30 minutes, 10-16% of the organic tanning agent, 0.5-1% of the tanning aid with pentaerythritol as the core and 0.2% of the mildewproof agent are added, the drum is rotated for 60 minutes, then 0.5% of sodium formate is added, the drum is rotated for 60 minutes, 0.5% of the alkali extracting agent is added twice, the drum is rotated for 60 and 120 minutes respectively, finally 50-100% of hot water is added, the temperature of the drum is increased to 38-42 DEG C, the drum is rotated for 20 minutes, then 0.1-0.5% of the tanning aid with pentaerythritol as the core and 0.1-0.3% of the aluminum tanning agent are added, the drum is rotated for 5 minutes, the process is stopped for 55 minutes, and the process is repeated for 6-10 times.

[0011] From the above description of the present application, compared with the prior art, the present application has the following advantages:

[0012] 1. The application uses the principle of dehydration condensation of carboxyl and amino to prepare hyperbranched high absorption chrome-free tanning aids. Without considering steric hindrance, one benzene hexacid molecule can graft six pentaerythritol, that is, an acid dipping aid with 18 amino groups and a certain molecular weight can be obtained. Similarly, with pentaerythritol as the core, without considering steric hindrance, four benzene hexacid can be grafted, and twenty carboxyl can graft twenty pentaerythritol, that is, a macromolecular tanning aid containing up to 60 amino groups can be obtained. However, due to the space effect, 3-4 pentaerythritol can be grafted with benzene hexacid as the core; 3-4 benzene hexacid can be grafted with pentaerythritol as the core, and the grafted single benzene hexacid can only graft 2-3 pentaerythritol. This hyperbranched structure has a large number of amino groups, a certain amount of carboxyl and aromatic ring structure, the amino groups can provide positive charge center, form electrostatic interaction with skin collagen fibers and organic tanning agents, the carboxyl groups can form hydrogen bond with the carboxyl, hydroxyl and amino groups on the skin collagen fibers, and the aromatic ring structure can produce π-π interaction with the organic chrome-free tanning agents with aromatic structure.

[0013] 2. The acid dipping aid with benzene hexacid as the core has strong cationicity, zeta potential ≥ 20 mV, and also has suitable particle size and dispersion performance, particle size 300-800 nm, particle size distribution coefficient 0.150-0.350.

[0014] 3. The tanning aid with pentaerythritol as the core also has strong cationicity, zeta potential ≥ 25 mV, and also has suitable particle size and dispersion performance, particle size 600-1500 nm, particle size distribution coefficient 0.250-0.450.

[0015] 4. The use of the two aids can significantly reduce the COD and BOD5 of the waste liquid, the COD can be reduced by about 15%, and the BOD5 can be reduced by about 10%.

[0016] 5. The use of the two aids can also improve the shrinkage temperature and softness of white wet leather, the shrinkage temperature of white wet leather ≥ 78℃, and the softness ≥ 3.5.

[0017] 6. The use of the two aids promotes the adsorption and combination of skin collagen fibers to organic chrome-free tanning agents, and improves the storage performance of white wet leather, which can be stored for more than 3 months at 20℃ and 55% humidity. DETAILED DESCRIPTION

[0018] Example 1:

[0019] A preparation method of high absorption and storage resistant organic tanning aid based on chrome-free tanning, including acid dipping aid with benzene hexacid as the core and tanning aid with pentaerythritol as the core;

[0020] The preparation steps of the mordanting agent with pentaerythritol as the core are as follows: 100 parts of pentaerythritol and 600 parts of benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid are uniformly mixed, the temperature is slowly raised to 180 DEG C under the protection of nitrogen, 8 parts of concentrated sulfuric acid are added dropwise within 1h, then the temperature is continuously kept for 2h, the temperature is slowly reduced to room temperature, then the excess pentaerythritol is removed by rotary evaporation, the reaction product is transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.2, and the mordanting agent with pentaerythritol as the core is obtained.

[0021] The preparation steps of the mordanting agent with pentaerythritol as the core are as follows: 100 parts of pentaerythritol and 600 parts of benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid are uniformly mixed, the temperature is slowly raised to 180 DEG C under the protection of nitrogen, 8 parts of concentrated sulfuric acid are added dropwise within 1h, then the temperature is continuously kept for 2h, the temperature is slowly reduced to room temperature, then the excess pentaerythritol is removed by rotary evaporation, the reaction product is transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.2, and the mordanting agent with pentaerythritol as the core is obtained.

[0022] Example 2:

[0023] A preparation method of a high-absorption storage-resistant organic tanning agent based on chrome-free tanning, comprising a mordanting agent with benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid as the core and a tanning agent with pentaerythritol as the core.

[0024] The preparation steps of the mordanting agent with pentaerythritol as the core are as follows: 100 parts of pentaerythritol and 600 parts of benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid are uniformly mixed, the temperature is slowly raised to 180 DEG C under the protection of nitrogen, 8 parts of concentrated sulfuric acid are added dropwise within 1h, then the temperature is continuously kept for 2h, the temperature is slowly reduced to room temperature, then the excess pentaerythritol is removed by rotary evaporation, the reaction product is transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.2, and the mordanting agent with pentaerythritol as the core is obtained.

[0025] The preparation steps of the tanning aid with pentaerythritol as the core are as follows: 100 parts of pentaerythritol, 525 parts of benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid are uniformly mixed, under the protection of nitrogen, the temperature is slowly raised to 190 DEG C, 16 parts of concentrated sulfuric acid is added dropwise within 1h, then it is continuously kept for 3h, the temperature is slowly reduced to room temperature, then the excess benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid is removed by rotary evaporation, the reactants are transferred into a flask, 1500 parts of pentaerythritol is added, after being uniformly mixed, under the protection of nitrogen, the temperature is slowly raised to 210 DEG C, 30 parts of concentrated sulfuric acid is added dropwise within 1h, then it is kept for 5h, the temperature is slowly reduced to room temperature, then the excess pentaerythritol is removed by rotary evaporation, the reactants are transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.5, thus the tanning aid with pentaerythritol as the core is obtained.

[0026] Example 3:

[0027] A preparation method of a high-absorption storage-resistant organic tanning aid based on chrome-free tanning, comprising an acid immersion aid with benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid as the core and a tanning aid with pentaerythritol as the core;

[0028] The preparation steps of the acid immersion aid with benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid as the core are as follows: 100 parts of benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid, 800 parts of pentaerythritol are uniformly mixed, under the protection of nitrogen, the temperature is slowly raised to 200 DEG C, 18 parts of concentrated sulfuric acid is added dropwise within 1h, then it is continuously kept for 4h, the temperature is slowly reduced to room temperature, then the excess pentaerythritol is removed by rotary evaporation, the reactants are transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.0, thus the acid immersion aid with benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid as the core is obtained.

[0029] The preparation steps of the tanning aid with pentaerythritol as the core are as follows: 100 parts of pentaerythritol, 525 parts of benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid are uniformly mixed, under the protection of nitrogen, the temperature is slowly raised to 190 DEG C, 16 parts of concentrated sulfuric acid is added dropwise within 1h, then it is continuously kept for 3h, the temperature is slowly reduced to room temperature, then the excess benzene-1, 2, 3, 4, 5, 6-hexacarboxylic acid is removed by rotary evaporation, the reactants are transferred into a flask, 1500 parts of pentaerythritol is added, after being uniformly mixed, under the protection of nitrogen, the temperature is slowly raised to 210 DEG C, 30 parts of concentrated sulfuric acid is added dropwise within 1h, then it is kept for 5h, the temperature is slowly reduced to room temperature, then the excess pentaerythritol is removed by rotary evaporation, the reactants are transferred into a flask, hydrochloric acid is used to adjust the pH value to 1.5, thus the tanning aid with pentaerythritol as the core is obtained.

[0030] The acid immersion aid / tanning aid obtained in example 1, example 2 and example 3 is subjected to experimental detection, and the obtained experimental data is shown in table 1.

[0031] Table 1

[0032]

[0033] Example 4

[0034] A high-absorption storage-resistant organic tanning aid based on chrome-free tanning, at least including pickling process and tanning process;

[0035] The specific steps of the pickling process are as follows: control the temperature of the drum to be 22°C, add 25% water, add 3% salt, rotate for 10 minutes, add 0.4% formic acid, 0.4% benzene hexacid-based pickling aid, rotate for 20 minutes, finally add 1.2% sulfuric acid, 0.3% benzene hexacid-based pickling aid, rotate for 5 minutes, stop for 25 minutes, repeat 4 times, based on the weight of the softened skin.

[0036] The specific steps of the tanning process are as follows: control the temperature of the drum to be 28°C, add 0.6% acid-resistant fatliquoring agent (B1, Tompul Chemical), rotate for 15 minutes, add 5% organic tanning agent (F90, Star), rotate for 30 minutes, add 10% organic tanning agent, 0.6% pentaerythritol-based tanning aid, 0.2% mildew inhibitor (30L, Bakeman), rotate for 60 minutes, then add 0.5% sodium formate, rotate for 60 minutes, add 0.5% alkali extracting agent (magnesium oxide) in two times, rotate for 60 and 120 minutes respectively, finally add 100% hot water to raise the temperature of the drum to 30°C, rotate for 20 minutes, then add 0.3% pentaerythritol-based tanning aid, 0.2% aluminum tanning agent (BN, BASF), rotate for 5 minutes, stop for 55 minutes, repeat 10 times.

[0037] The pickling aid and tanning aid added in this example are prepared in Example 1.

[0038] Example 5

[0039] The application of high-absorption storage-resistant organic tanning aid based on chrome-free tanning in this example is basically the same as that in Example 4, except that the pickling aid and tanning aid added in this example are prepared in Example 2.

[0040] Example 6

[0041] The application of high-absorption storage-resistant organic tanning aid based on chrome-free tanning in this example is basically the same as that in Example 4, except that the pickling aid and tanning aid added in this example are prepared in Example 3.

[0042] Comparative Example: The process of the comparative example is basically the same as that of Example 4, except that the comparative example does not add pickling aid and tanning aid.

[0043] The waste liquid and white wet leather obtained from the comparative example, Example 4, Example 5 and Example 6 are subjected to experimental detection, and the experimental data are shown in Table 2.

[0044] Table 2

[0045]

[0046] The above merely illustrates the specific embodiments of the present application, but the design concept of the present application is not limited thereto, and any non-essential modification of the present application by using the concept shall be deemed as the infringement of the protection scope of the present application.

Claims

1. A method for preparing a highly absorbent and storage-resistant organic tanning aid based on chromium-free tanning, characterized in that, This includes pickling auxiliaries with benzoic acid as the core and tanning auxiliaries with pentaerythritol as the core; The preparation steps of the pickling agent with benzohexanic acid as the core are as follows: Take 100 parts of benzohexanic acid and 600-800 parts of pentaerythritol and mix them evenly. Under the protection of nitrogen, slowly raise the temperature to 180-200°C. Add 5-20 parts of concentrated sulfuric acid dropwise over 1 hour, and then continue to keep warm for 1-5 hours. Slowly lower the temperature to room temperature and remove excess pentaerythritol by rotary evaporation. Transfer the reaction mixture to a flask and adjust the pH value to 1.0-1.5 with hydrochloric acid to obtain the pickling agent with benzohexanic acid as the core. The preparation steps of the tanning auxiliary agent with pentaerythritol as the core are as follows: Take 100 parts of pentaerythritol and 450-600 parts of benzoic acid and mix them evenly. Under nitrogen protection, slowly raise the temperature to 180-200°C, add 8-30 parts of concentrated sulfuric acid dropwise over 1 hour, and then continue to keep warm for 1-5 hours. Slowly lower the temperature to room temperature and remove excess benzoic acid by rotary evaporation. Transfer the reactants to a flask, add 1200-1800 parts of pentaerythritol, mix evenly, and under nitrogen protection, slowly raise the temperature to 200-220°C. Add 15-50 parts of concentrated sulfuric acid dropwise over 1 hour, and then keep warm for 3-7 hours. Slowly lower the temperature to room temperature and remove excess pentaerythritol by rotary evaporation. Transfer the reactants to a flask and adjust the pH value to 1.0-1.5 with hydrochloric acid to obtain the tanning auxiliary agent with pentaerythritol as the core.

2. The application of a high-absorption, storage-resistant organic tanning agent based on chromium-free tanning as described in claim 1, characterized in that, It includes at least the pickling process and the tanning process; The specific steps of the pickling process are as follows: Based on the weight of the softened leather, control the drum temperature at 20-25°C, add 20-40% water, add 3-5% salt, rotate for 10 minutes, add 0.2-0.5% formic acid and 0.1-0.5% benzoic acid as the core pickling aid, rotate for 20 minutes, and finally add 1-1.5% sulfuric acid and 0.2-0.6% benzoic acid as the core pickling aid, rotate for 5 minutes, stop for 25 minutes, and repeat 4 times. The specific steps of the tanning process are as follows: Based on the weight of the softened leather, control the drum temperature at 25-30°C, add 0.5-1% of acid-resistant fatliquoring agent, rotate for 15 minutes, add 5-8% of organic tanning agent, rotate for 30 minutes, add 10-16% of organic tanning agent, 0.5-1% of pentaerythritol as the core tanning aid, and 0.2% of mildew inhibitor, rotate for 60 minutes, then add 0.5% of sodium formate, rotate for 60 minutes, add 0.5% of alkali extractant in two batches, rotating for 60 minutes and 120 minutes respectively, and finally add 50-100% hot water to raise the drum temperature to 38-42°C, rotate for 20 minutes, then add 0.1-0.5% of pentaerythritol as the core tanning aid and 0.1-0.3% aluminum tanning agent, rotate for 5 minutes, stop for 55 minutes, and repeat 6-10 times.

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