Preparation method and application of amino resin retanning agent based on tannery waste horsehair

Abstract

The application relates to a preparation method of an amino resin retanning agent based on tanning waste cattle hair, 100 parts of waste cattle hair, deionized water, alkali, calcium hydroxide, polyaluminum chloride and polyacrylamide are added for flocculation and precipitation, the filtrate is taken and dried; the dried product is dissolved in water, the pH value is adjusted, 4,4-dimethoxy-2-butanone (CAS:5436-21-5) and sulfuric acid are added; the product is dissolved in thionyl chloride, N,N-dimethylformamide is added, and rotary evaporation is carried out; aldehyde group keratin, formaldehyde, acetaldehyde and glyoxal are added, ethanol is added, the pH value is adjusted, p-aldehyde benzoic acid is added, the pH value is adjusted, and vacuum drying is carried out. In the application, the dirt and impurities in the cattle hair are flocculated by the flocculation of calcium hydroxide, a large amount of water and surfactant washing is saved; the residual amino and hydroxyl groups are consumed by activated p-aldehyde benzoic acid, more active carboxyl groups and active aldehyde groups are introduced, the reaction activity of melamine grafted keratin and skin collagen fibers is improved, and tanning and filling properties are given.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tanning technology, in particular to a preparation method and application of an amino resin refilling agent based on tanning waste cattle hair. BACKGROUND

[0002] In the tanning process, lime and sulfidized alkali are used for liming and unhairing treatment of rawhide, and a large amount of cattle hair in the form of solid waste will appear after the treatment of rawhide. The cattle hair treated with lime and sulfidized alkali contains a lot of dirt and impurities. The traditional treatment method is to use a large amount of water combined with a surfactant and a degreasing agent for cleaning, which will produce a large amount of high-COD wastewater. In addition, although the keratin molecule structure has carboxyl and amino groups, the activity is low, and although grafting modification can be theoretically carried out on the structure, the grafting rate is usually low. Therefore, how to activate the functional groups on the keratin and improve the grafting rate has become another difficulty in the comprehensive utilization of keratin. SUMMARY

[0003] The present application provides a preparation method and application of an amino resin refilling agent based on tanning waste cattle hair to solve the problems of a large amount of high-COD wastewater produced by the treatment of solid waste cattle hair and low activity and grafting rate of keratin after treatment.

[0004] The present application adopts the following technical scheme:

[0005] A preparation method of an amino resin refilling agent based on tanning waste cattle hair, comprising the following steps:

[0006] Step 1: Take 100 parts of waste cattle hair, add 500 parts of deionized water, mix uniformly, then add 8-12 parts of alkali, and react at 60-90℃ for 3-6 hours. After cooling to room temperature, add 5-10 parts of calcium hydroxide, 1 part of polyaluminum chloride and 1 part of polyacrylamide flocculation and precipitation. After filtering and precipitating, take the filtrate, adjust the pH value to 7-8 by adding sulfuric acid, and vacuum dry to obtain keratin powder;

[0007] Step 2: Take 100 parts of keratin powder and dissolve it in 200 parts of water. Adjust the pH value with disodium hydrogen phosphate and sodium dihydrogen phosphate so that it is always controlled at 6.8-7.2. Add 280-400 parts of 4,4-dimethoxy-2-butanone (CAS: 5436-21-5), stir uniformly, then raise the reaction temperature to 40-60℃, and keep the temperature constant for 1-3h. Then add sulfuric acid to adjust the pH to 2.5-4.5, and the aldehyde group keratin is obtained.

[0008] Step 3, activation of p-formyl benzoic acid: take 100 parts of p-formyl benzoic acid dissolved in 300 parts of thionyl chloride, add 1-5 parts of N, N-dimethylformamide, react at 35-50℃ for 2-4h, and remove the excess thionyl chloride and N, N-dimethylformamide by rotary evaporation to obtain activated p-formyl benzoic acid;

[0009] Step 4, preparation of melamine resin grafted keratin: take 100 parts of melamine and slowly disperse in 300 parts of water, add 100-300 parts of aldehyde-keratin, 0-100 parts of formaldehyde, 50-200 parts of acetaldehyde, 50-200 parts of glyoxal, and add 5-8% of the total amount of aldehydes of ethanol, mix uniformly, adjust the pH to 7.5-9.0 with sodium hydroxide, react at 35-40℃ for 15-30 minutes, then add 100-200 parts of activated p-formyl benzoic acid, keep warm for 10-15 minutes, then slowly reduce to room temperature, adjust the pH to 6.0-7.0 with sulfuric acid, and vacuum dry to obtain a melamine resin grafted keratin retanning agent.

[0010] Further improvement, the above-mentioned alkali at least contains calcium hydroxide, and can contain sodium hydroxide and potassium hydroxide.

[0011] An application of a tanning agent based on tanning waste cattle hair, at least including a retanning process and a filling process;

[0012] The specific steps of the retanning process are: control the drum temperature to be 30-35℃, add 75-150% water, add 2-4% melamine resin grafted keratin retanning agent, 1-3% lecithin fatting agent, and 1-3% acid-resistant acrylic resin retanning agent, rotate for 30-60 minutes, then add 2-4% melamine resin grafted keratin retanning agent, 1-3% synthetic tanning agent, and 1-3% synthetic fatting agent, rotate for 60-120 minutes, add 100-150% water, add 1.2-1.8% formic acid in three times, rotate for 10, 10 and 20 minutes respectively, add 4-6% chrome tanning agent, 2-4% chrome-containing tannin, and 1-3% acid-resistant fatting agent, rotate for 120-180 minutes, then add 2% sodium formate, rotate for 20 minutes, add 2% baking soda, rotate for 60 minutes, and add 2% ammonium bicarbonate, rotate for 60 minutes;

[0013] The specific steps of the filling process are as follows: the temperature of the drum is controlled at 30-35 DEG C based on the weight of the blue wet leather, 50-100% water is added, 3-9% small molecule acrylic acid, 1-3% large molecule acrylic acid, 1-2% synthetic fatliquoring agent are added, the drum is rotated for 30 minutes, 6-9% melamine resin grafted keratin retanning agent, 1-3% dicyandiamide resin retanning agent, 1-3% dispersed tannin are added, the drum is rotated for 60 minutes, 3-6% synthetic tanning agent, 3-9% extract of tannin, 1-2% synthetic fatliquoring agent are added, the drum is rotated for 120 minutes. Finally, 0.6% formic acid is added, and the drum is rotated for 30 minutes.

[0014] From the above description of the present application, compared with the prior art, the present application has the following advantages:

[0015] 1. The present application uses the flocculation of calcium hydroxide to flocculate the dirt and impurities in the cow hair, saving a large amount of water and surfactant washing. In the process of flocculation, the alkalinity of calcium hydroxide can also well hydrolyze the cow hair to extract keratin. The use of 4,4-dimethoxy-2-butanone (CAS: 5436-21-5) to activate keratin is to use the reactivity of amino and carbonyl to graft a small molecule organic compound containing active carbonyl structure with one end protected by alcohol onto the keratin molecule. Then under weak acid conditions, the protection structure is hydrolyzed to obtain aldehyde functionalized keratin. The aldehyde functionalized keratin can further react with the amino group of melamine to increase the molecular weight of melamine grafted keratin with formaldehyde, acetaldehyde, glyoxal as chain extender. Finally, adding a certain amount of activated p-aldehyde benzoic acid can further consume residual amino groups, hydroxyl groups, introduce more active carboxyl and active aldehyde groups, thereby improving the reactivity of melamine grafted keratin and collagen fibers, and giving it certain tannin and filling properties.

[0016] 2. The keratin prepared by the method of the present application has a solid content of ≥90%, an ash content of ≤10%, a water insoluble content of ≤5%, a water soluble content of ≥85%, a suitable particle size, a particle size distribution coefficient and a zeta potential, a particle size of 200-500 nm, a particle size distribution coefficient of 0.100-0.250, and a zeta potential of ≤-20 mV.

[0017] 3. The melamine grafted keratin retanning agent of the present application has a suitable particle size and particle size distribution coefficient, a particle size of 1500-3000 nm, and a particle size distribution coefficient of 0.300-0.600.

[0018] 4. The melamine grafted keratin retanning agent of the present application has a relatively ideal health and safety performance, a formaldehyde content of ≤200 ppm, a heavy metal arsenic content of ≤100 ppm, a lead content of ≤100 ppm, and a cadmium content of ≤100 ppm.

[0019] 5.The melamine grafted keratin retanning agent has good tanning and filling properties. After the melamine grafted keratin treatment, the raw leather shrinkage temperature is greater than or equal to 90℃ -1 , the tear force is greater than or equal to 50N, the burst height is greater than or equal to 7mm, and the burst strength is greater than or equal to 300N·mm -1 ; at the same time, it has good health and safety performance, the formaldehyde content is less than or equal to 75ppm, the hexavalent chromium is less than or equal to 10ppm, the heavy metal arsenic is less than or equal to 100ppm, the lead is less than or equal to 100ppm, and the cadmium is less than or equal to 100ppm. DETAILED DESCRIPTION

[0020] Example 1

[0021] A preparation method of an amino resin retanning agent based on tanning waste cow hair, comprising the following steps:

[0022] Step 1, preparation of keratin powder: take 100 parts of waste cow hair, add 500 parts of deionized water, mix uniformly, then add 12 parts of calcium hydroxide, react at 85℃ for 6 hours, cool to room temperature, then add 5 parts of calcium hydroxide, 1 part of polyaluminum chloride, and 1 part of polyacrylamide flocculation and precipitation, filter the precipitate, take the filtrate, add sulfuric acid to adjust the pH value to 8, and vacuum dry to obtain keratin powder.

[0023] Step 2, preparation of aldehyde-keratin: take 100 parts of keratin powder and dissolve in 200 parts of water, adjust the pH value with disodium hydrogen phosphate and sodium dihydrogen phosphate so that it is always controlled at 6.8-7.2, add 280 parts of 4,4-dimethoxy-2-butanone (CAS:5436-21-5), stir uniformly, then raise the reaction temperature to 40℃, keep constant temperature for 3h, then add sulfuric acid to adjust the pH to 2.5, and aldehyde-keratin is obtained.

[0024] Step 3, activation of p-formaldehyde benzoic acid: take 100 parts of p-formaldehyde benzoic acid and dissolve in 300 parts of thionyl chloride, add 4 parts of N,N-dimethylformamide, react at 45℃ for 2h, rotary evaporate to remove excess thionyl chloride and N,N-dimethylformamide, and activated p-formaldehyde benzoic acid is obtained.

[0025] Step 4, preparation of melamine resin grafted keratin: take 100 parts of melamine and slowly disperse in 300 parts of water, add 200 parts of aldehyde-keratin, 50 parts of formaldehyde, 50 parts of acetaldehyde, and 50 parts of glyoxal, and add 5% of ethanol according to the total amount of aldehydes, mix uniformly, then use sodium hydroxide to adjust the pH to 9.0, react at 35℃ for 30 minutes, then add 120 parts of activated p-formaldehyde benzoic acid, keep warm for 15 minutes, then slowly reduce to room temperature, adjust the pH value to 6.0 with sulfuric acid, and vacuum dry to obtain the melamine resin grafted keratin retanning agent.

[0026] Example 2:

[0027] A method for preparing an amino resin retanning agent based on tannery waste cattle hair, comprising the following steps:

[0028] Step 1, preparation of keratin powder: take 100 parts of waste cattle hair, add 500 parts of deionized water, mix uniformly, then add 8 parts of calcium hydroxide, 5 parts of sodium hydroxide, react at 70°C for 5 hours, cool to room temperature, then add 8 parts of calcium hydroxide, 1 part of polyaluminum chloride, 1 part of polyacrylamide flocculation and precipitation, filter the precipitate, take the filtrate, add sulfuric acid to adjust the pH value to 7, and vacuum dry to obtain keratin powder.

[0029] Step 2, preparation of aldehyde-keratin: take 100 parts of keratin powder dissolved in 200 parts of water, adjust the pH value with disodium hydrogen phosphate and sodium dihydrogen phosphate so that it is always controlled at 6.8-7.2, add 335 parts of 4,4-dimethoxy-2-butanone (CAS:5436-21-5), stir uniformly, then raise the reaction temperature to 50°C, keep constant temperature for 2h, then add sulfuric acid to adjust the pH to 3.5, and aldehyde-keratin is obtained.

[0030] Step 3, activation of p-formyl benzoic acid: take 100 parts of p-formyl benzoic acid dissolved in 300 parts of thionyl chloride, add 2 parts of N,N-dimethylformamide, react at 35°C for 4h, rotary evaporate to remove excess thionyl chloride and N,N-dimethylformamide, and activated p-formyl benzoic acid is obtained.

[0031] Step 4, preparation of melamine resin grafted keratin: take 100 parts of melamine, slowly disperse in 300 parts of water, add 150 parts of aldehyde-keratin, 150 parts of acetaldehyde, 50 parts of glyoxal, and add 6% of ethanol based on the total amount of aldehydes, mix uniformly, then use sodium hydroxide to adjust the pH to 8.0, react at 40°C for 15 minutes, then add 200 parts of activated p-formyl benzoic acid, keep warm for 10 minutes, then slowly reduce to room temperature, adjust the pH value to 6.5 with sulfuric acid, and vacuum dry to obtain melamine resin grafted keratin retanning agent.

[0032] Example 3:

[0033] A method for preparing an amino resin retanning agent based on tannery waste cattle hair, comprising the following steps:

[0034] Step 1, preparation of keratin powder: take 100 parts of waste cattle hair, add 500 parts of deionized water, mix uniformly, then add 3 parts of calcium hydroxide, 3 parts of sodium hydroxide, 3 parts of potassium hydroxide, react at 80°C for 4 hours, cool to room temperature, then add 10 parts of calcium hydroxide, 1 part of polyaluminum chloride, 1 part of polyacrylamide flocculation and precipitation, filter the precipitate, take the filtrate, add sulfuric acid to adjust the pH value to 7, and vacuum dry to obtain keratin powder.

[0035] Step 2, preparation of aldehyde group keratin: take 100 parts of keratin powder dissolved in 200 parts of water, adjust the pH value with disodium hydrogen phosphate and sodium dihydrogen phosphate, so that it is always controlled at 6.8-7.2, add 385 parts of 4,4-dimethoxy-2-butanone (CAS:5436-21-5), after stirring uniformly, the reaction temperature is raised to 60℃, constant temperature for 1h, then add sulfuric acid, adjust the pH to 4.5, aldehyde group keratin is obtained.

[0036] Step 3, activation of p-aldehyde benzoic acid: take 100 parts of p-aldehyde benzoic acid dissolved in 300 parts of thionyl chloride, add 3 parts of N,N-dimethylformamide, react at 40℃ for 3h, rotary evaporation to remove excess thionyl chloride and N,N-dimethylformamide, activated p-aldehyde benzoic acid is obtained.

[0037] Step 4, preparation of melamine resin grafted keratin: take 100 parts of melamine, slowly dispersed in 300 parts of water, add 300 parts of aldehyde group keratin, 20 parts of formaldehyde, 50 parts of acetaldehyde, 50 parts of glyoxal, and according to 7% of the total amount of aldehyde, add ethanol, mix uniformly, use sodium hydroxide to adjust the pH to 8.5, react at 38℃ for 20 minutes, then add 160 parts of activated p-aldehyde benzoic acid, keep warm for 12 minutes, then slowly reduce to room temperature, adjust the pH value to 7.0 with sulfuric acid, vacuum drying, melamine resin grafted keratin retanning agent is obtained.

[0038] The carboxylated keratin, melamine grafted keratin obtained in example 1, example 2, example 3 are subjected to practical detection, and the experimental data are shown in table 1 as follows:

[0039] Table 1

[0040]

[0041] Example 4: application of a kind of amino resin retanning agent based on tanning waste cattle hair, including retanning process, filling process and fatliquoring process, the melamine resin grafted keratin retanning agent added in this embodiment is obtained in example 1;

[0042] The specific steps of the retanning process are as follows: Based on the weight of the wet blue leather, control the drum temperature at 32℃, add 100% water, then add 3% melamine resin grafted keratin retanning agent, 2% lecithin fatliquoring agent (NLM, Starr), and 3% acid-resistant acrylic resin retanning agent (1084, Lanxess Chemical). Rotate for 30 minutes. Then add 3% melamine resin grafted keratin retanning agent, 3% synthetic tanning agent (LR-7, Lining Technology), and 3% synthetic fatliquoring agent (94S, Sima Chemical). Rotate for 60 minutes. Add 100% water, then add 1.5% formic acid in three portions, rotating for 10, 10, and 20 minutes respectively. Finally, add 6% chrome tanning agent (Tankrom AB). Turkey), 4% chromium-containing tannin (HB, Brothers Chemical), 3% acid-resistant fatliquoring agent (B1, Tompler Chemical), rotate for 180 minutes, then add 2% sodium formate, rotate for 20 minutes, add 2% baking soda, rotate for 60 minutes, add 2% ammonium bicarbonate, rotate for 60 minutes, drain.

[0043] The specific steps of the filling process are as follows: Based on the weight of wet blue leather, control the drum temperature at 32℃, add 50% water, 6% small molecule acrylic acid (TP340, Zhiqi Trading), 3% large molecule acrylic acid (1084, Lanxess Chemical), and 2% synthetic fatliquoring agent (94S, Sima Chemical), and rotate for 30 minutes. Add 6% melamine resin grafted keratin retanning agent, 3% dicyandiamide resin retanning agent (DC-11, Lining Technology), and 2% dispersed tannin (TM, BASF Chemical), and rotate for 60 minutes. Add 4% synthetic tanning agent (RL, Derui Chemical), 6% tannin (ATO, Jinfeng Leather Chemical), and 2% synthetic fatliquoring agent (94S, Sima Chemical), and rotate for 120 minutes. Finally, add 0.6% formic acid and rotate for 30 minutes.

[0044] The specific steps of the fatliquoring process are as follows: raise the drum temperature to 48℃, add 100% water, add 2% protein filler (FB, Sichuan Desai'er), rotate for 20 minutes, add 3% synthetic phosphate fatliquoring agent (LWK, Lining Technology), 3% modified cow hoof oil (NT, Lining Technology), rotate for 30 minutes, add 3% sulfonated synthetic oil (SA, Lining Technology), 3% synthetic fatliquoring agent (BSFR, Lining Technology), 3% lecithin (LC, Italian Unitecco), 3% lanolin (ZLN, Bisso Chemical), rotate for 120 minutes, and finally add 2.5% formic acid in four portions, rotating for 10, 10, 10, and 30 minutes respectively. After draining, the raw leather is obtained.

[0045] Comparative Example: The application of the amino resin retanning agent based on waste cow hair in this comparative example is basically the same as that in Example 4. The difference is that the melamine resin grafted keratin retanning agent obtained in Example 1 is not added to the comparative example.

[0046] The experimental detection was carried out on the crust leather obtained from the comparative example and example 4, and the experimental data are shown in Table 2 below:

[0047] Table 2

[0048]

[0049] The above merely is the specific embodiment of the present application, but the design concept of the present application is not limited to this, and any non-essential modification of the present application by using this concept should belong to the behavior of infringing the protection scope of the present application.

Claims

1. A method for the preparation of amino resin-based retanning agent based on tannery waste horsehairs, characterized by, The method comprises the following steps: Step 1: 100 parts of waste cattle hair is added into 500 parts of deionized water, and then 8-12 parts of alkali is added after mixing evenly, and the mixture is reacted at 60-90°C for 3-6 hours, and then the mixture is cooled to room temperature, and 5-10 parts of calcium hydroxide, 1 part of polyaluminum chloride and 1 part of polyacrylamide are added for flocculation and precipitation, and then the precipitate is filtered, and the filtrate is obtained, and sulfuric acid is added to adjust the pH value to 7-8, and then the mixture is vacuum dried to obtain keratin powder; Step 2: 100 parts of keratin powder is dissolved in 200 parts of water, and the pH value is adjusted by using disodium hydrogen phosphate and sodium dihydrogen phosphate to control the pH value at 6.8-7.2 all the time, and then 280-400 parts of 4,4-dimethoxy-2-butanone is added, and the mixture is stirred uniformly, and then the reaction temperature is raised to 40-60°C, and the mixture is kept at constant temperature for 1-3 hours, and then sulfuric acid is added to adjust the pH value to 2.5-4.5, and then the aldehyde group keratin is obtained; Step 3: The activation of p-formyl benzoic acid: 100 parts of p-formyl benzoic acid is dissolved in 300 parts of thionyl chloride, and then 1-5 parts of N,N-dimethylformamide is added, and the mixture is reacted at 35-50°C for 2-4 hours, and then the excess thionyl chloride and N,N-dimethylformamide are removed by rotary evaporation, and then the activated p-formyl benzoic acid is obtained; Step 4: The preparation of melamine resin grafted keratin: 100 parts of melamine is slowly dispersed in 300 parts of water, and then 100-300 parts of aldehyde group keratin, 0-100 parts of formaldehyde, 50-200 parts of acetaldehyde, 50-200 parts of glyoxal and 5-8% of ethanol based on the total amount of aldehydes are added, and then the mixture is mixed uniformly, and then sodium hydroxide is used to adjust the pH value to 7.5-9.0, and then the mixture is reacted at 35-40°C for 15-30 minutes, and then 100-200 parts of activated p-formyl benzoic acid is added, and the mixture is kept warm for 10-15 minutes, and then the mixture is slowly cooled to room temperature, and then sulfuric acid is used to adjust the pH value to 6.0-7.0, and then the mixture is vacuum dried to obtain the melamine resin grafted keratin retanning agent, i.e. amino resin retanning agent; The alkali contains at least calcium hydroxide, and optionally contains sodium hydroxide and potassium hydroxide.

2. Use of the amino resin re-fleshing agent prepared according to the method for preparing an amino resin re-fleshing agent based on tannery waste horsehair according to claim 1, characterized in that: The method at least comprises a retanning process and a filling process; The specific steps of the retanning process are as follows: the weight of the blue wet leather is taken as the basis, the drum temperature is controlled at 30-35°C, 75-150% of water is added, 2-4% of the melamine resin grafted keratin retanning agent according to claim 1, 1-3% of lecithin fat-liquoring agent and 1-3% of acid-resistant acrylic resin retanning agent are added, and the mixture is rotated for 30-60 minutes, and then 2-4% of the melamine resin grafted keratin retanning agent according to claim 1, 1-3% of synthetic tanning agent and 1-3% of synthetic fat-liquoring agent are added, and the mixture is rotated for 60-120 minutes, 100-150% of water is added, 1.2-1.8% of formic acid is added in three times, and the mixture is rotated for 10, 10 and 20 minutes respectively, 4-6% of chrome tanning agent, 2-4% of chromium-containing tannin and 1-3% of acid-resistant fat-liquoring agent are added, and the mixture is rotated for 120-180 minutes, and then 2% of sodium formate is added, and the mixture is rotated for 20 minutes, 2% of baking soda is added, and the mixture is rotated for 60 minutes, and 2% of ammonium bicarbonate is added, and the mixture is rotated for 60 minutes. The specific steps of the filling process are as follows: the temperature of the drum is controlled at 30-35°C, 50-100% water, 3-9% small molecule acrylic acid, 1-3% large molecule acrylic acid, 1-2% synthetic fatliquoring agent are added, the drum is rotated for 30 minutes, 6-9% melamine resin grafted keratin re-tanning agent as described in claim 1, 1-3% dicyandiamide resin re-tanning agent, 1-3% dispersed tannin are added, the drum is rotated for 60 minutes, 3-6% synthetic tanning agent, 3-9% extract of quebracho, 1-2% synthetic fatliquoring agent are added, the drum is rotated for 120 minutes, and finally 0.6% formic acid is added, and the drum is rotated for 30 minutes.

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