阅读说明：本技术 一种合成加脂剂及其制备方法和应用 (Synthetic fat liquor, preparation method and application thereof ) 是由 冯练享 王顺平 白清泉 于 2020-12-23 设计创作，主要内容包括：本发明提供了一种合成加脂剂及其制备方法和应用,涉及皮革化工技术领域。本发明提供的合成加脂剂,制备原料包括以下重量份的组分：N-油酰肌氨酸353～706份；2,2-二羟甲基丙酸106～212份；降熔点助剂194～388份；马来酰二乙醇胺93～370份；酸性催化剂5～30份；乳化剂5～30份；水600～2000份。本发明提供的合成加脂剂能够提高皮革的柔软度、增厚率、抗撕力和吸收率；而且本发明提供的合成加脂剂稳定性高,不易酸败或水解。(The invention provides a synthetic fat liquor, a preparation method and application thereof, and relates to the technical field of leather chemical industry. The synthetic fat liquor provided by the invention comprises the following raw materials in parts by weight: 353-706 parts of N-oleoyl sarcosine; 106-212 parts of 2, 2-dimethylolpropionic acid; 194-388 parts of a melting point reducing assistant; 93-370 parts of maleic diethanol amide; 5-30 parts of an acidic catalyst; 5-30 parts of an emulsifier; 600-2000 parts of water. The synthetic fat liquor provided by the invention can improve the softness, thickening rate, tearing resistance and absorption rate of leather; the synthetic fat liquor provided by the invention has high stability and is not easy to rancidity or hydrolysis.)

1. The synthetic fat liquor is characterized in that the preparation raw materials comprise the following components in parts by weight:

353-706 parts of N-oleoyl sarcosine;

106-212 parts of 2, 2-dimethylolpropionic acid;

194-388 parts of a melting point reducing assistant;

93-370 parts of maleic diethanol amide;

5-30 parts of an acidic catalyst;

5-30 parts of an emulsifier;

600-2000 parts of water.

2. The synthetic fatliquor of claim 1, wherein the melting point reducing additive is a eutectic solvent formed by choline chloride and urea; the mol ratio of the choline chloride to the urea is 1: 1-3.

3. Synthetic fatliquor according to claim 1 or 2, characterised in that the molar ratio of melting point depressant additive to 2, 2-dimethylolpropionic acid is 1: 1.

4. The synthetic fatliquor of claim 1 wherein the molar ratio of N-oleoylsarcosine, 2-dimethylolpropionic acid and maleyl diethanolamine is (1-2) to (1-4).

5. Synthetic fatliquor according to claim 1, characterised in that the acidic catalyst is p-toluene sulphonic acid, a solid acid catalyst or concentrated sulphuric acid.

6. Synthetic fatliquor according to claim 1, characterized in that the emulsifier is a non-ionic surfactant or an anionic surfactant.

7. A method of preparing a synthetic fatliquor according to any one of claims 1 to 6 comprising the steps of:

mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid;

mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst to perform a first esterification reaction to obtain a first reactant;

mixing the first reactant and the maleic diethanol amide to perform a second esterification reaction to obtain a second reactant;

and mixing the second reactant with an emulsifier and water to obtain the synthetic fat liquor.

8. A method of preparing a synthetic fatliquor according to any one of claims 1 to 6 comprising the steps of:

mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid;

mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst, and carrying out a first esterification reaction to obtain a first product;

mixing maleic diethanol amine and an acidic catalyst, and carrying out a third esterification reaction to obtain a second product;

mixing the second product and the first product, and performing a fourth esterification reaction to obtain a third product;

and mixing the third product with an emulsifier and water to obtain the synthetic fat liquor.

9. The method according to claim 8, wherein the temperature of the third esterification reaction and the fourth esterification reaction is independently 100 to 200 ℃; the time is independently 2-5 h.

10. Use of the synthetic fat-liquoring agent according to any one of claims 1 to 6 or the synthetic fat-liquoring agent prepared by the preparation method according to any one of claims 7 to 9 in leather fat-liquoring.

Technical Field

The invention relates to the technical field of leather chemical industry, in particular to a synthetic fat liquor and a preparation method and application thereof.

Background

The greasing is a key process in the leather production, and the crust leather is greased reasonably and properly to absorb a proper amount of greasing materials, recover the original softness and elasticity of the crust leather, prevent the leather from being stiff and cracking and endow the leather with certain service performance. By the greasing, the tensile strength, the toughness, the elongation, the leather yield and the like of the leather are improved to some extent, meanwhile, the water resistance is obviously improved, and the leather is endowed with good hand feeling.

Most of the common leather fatting agents are emulsion prepared by emulsifying natural animal and vegetable oil through an emulsifier, or have self-emulsifying capacity through chemical modification, common modification modes comprise sulfation, oxidative sulfitation, phosphorylation, alcoholysis re-esterification and the like, and the production is greatly limited along with stricter environmental laws and regulations. For example, the sulfation modification requires washing with a large amount of saturated brine because an excessive amount of sulfuric acid is used, and thus a large amount of highly hydrochloric acid water is produced. The oxidative sulfitation modification easily discharges a large amount of VOC into the air, and the odor is large. The phosphorylation-modified product is rich in phosphorus because it remains in the wastewater during use. Moreover, natural animal and vegetable oil is easy to generate phenomena such as rancidity, hydrolysis and the like, more antioxidants are needed, and the cost is increased.

Disclosure of Invention

The synthetic fat liquor provided by the invention can improve the softness, thickening rate, tearing resistance and absorption rate of leather; the synthetic fat liquor provided by the invention has high stability and is not easy to rancidity or hydrolysis.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a synthetic fat liquor, which comprises the following raw materials in parts by weight:

353-706 parts of N-oleoyl sarcosine;

106-212 parts of 2, 2-dimethylolpropionic acid;

194-388 parts of a melting point reducing assistant;

93-370 parts of maleic diethanol amide;

5-30 parts of an acidic catalyst;

5-30 parts of an emulsifier;

600-2000 parts of water.

Preferably, the melting point reducing auxiliary agent is a eutectic solvent formed by choline chloride and urea; the mol ratio of the choline chloride to the urea is 1: 1-3.

Preferably, the molar ratio of the melting point reducing assistant to the 2, 2-dimethylolpropionic acid is 1: 1.

Preferably, the molar ratio of the N-oleoyl sarcosine to the 2, 2-dimethylolpropionic acid to the maleic acid diethanol amine is (1-2): 1-4).

Preferably, the acidic catalyst is p-toluenesulfonic acid, a solid acid catalyst or concentrated sulfuric acid.

Preferably, the emulsifier is a nonionic surfactant or an anionic surfactant.

The invention provides a preparation method of the synthetic fat liquor in the technical scheme, which comprises the following steps:

mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid;

mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst to perform a first esterification reaction to obtain a first reactant;

mixing the first reactant and the maleic diethanol amide to perform a second esterification reaction to obtain a second reactant;

and mixing the second reactant with an emulsifier and water to obtain the synthetic fat liquor.

The invention provides another preparation method of the synthetic fat liquor in the technical scheme, which comprises the following steps:

mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid;

mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst, and carrying out a first esterification reaction to obtain a first product;

mixing maleic diethanol amine and an acidic catalyst, and carrying out a third esterification reaction to obtain a second product;

mixing the second product and the first product, and performing a fourth esterification reaction to obtain a third product;

and mixing the third product with an emulsifier and water to obtain the synthetic fat liquor.

Preferably, the temperature of the third esterification reaction and the fourth esterification reaction is independently 100-200 ℃; the time is independently 2-5 h.

The invention provides an application of the synthetic fat liquor in the technical scheme or the synthetic fat liquor prepared by the preparation method in the technical scheme in leather fat liquor.

The invention provides a synthetic fat liquor, which comprises the following raw materials in parts by weight: 353-706 parts of N-oleoyl sarcosine; 106-212 parts of 2, 2-dimethylolpropionic acid; 194-388 parts of a melting point reducing assistant; 93-370 parts of maleic diethanol amide; 5-30 parts of an acidic catalyst; 5-30 parts of an emulsifier; 600-2000 parts of water. The method takes N-oleoyl sarcosine, 2-dimethylolpropionic acid and maleic acid diethanol amine as main raw materials, and because 2, 2-dimethylolpropionic acid and maleic acid diethanol amine have carboxyl and hydroxyl and 3 functional groups, a dendritic esterified substance can be formed during esterification; the melting point reducing auxiliary agent can reduce the melting point of the 2, 2-dimethylolpropionic acid, so that the reaction can be better carried out, and meanwhile, a certain moisture-preserving effect is achieved; the acidic catalyst is beneficial to improving the yield of the esterification reaction, and the emulsifier can improve the stability of the synthetic fatliquor emulsion. The synthetic fat liquor with higher branching degree is obtained through esterification reaction, and the softness and the tearing resistance of leather are improved; the synthetic fat liquor provided by the invention can be used as a leather fat liquor alone or can be used together with other types of fat liquors. In the process of preparing the synthetic fat liquor, no organic solvent is added to dissolve materials, no three wastes are generated, and the method is environment-friendly; the synthetic fat liquor provided by the invention has high stability and is not easy to rancidity or hydrolysis.

In the invention, the amido of the N-oleoyl sarcosine has weak cationic property in aqueous solution, has stronger bonding force with the collagen fiber of the leather, and can also form bonding with other anionic fatting agents, retanning agents and the like, thereby improving the absorption rate of the leather.

Detailed Description

The invention provides a synthetic fat liquor, which comprises the following raw materials in parts by weight:

353-706 parts of N-oleoyl sarcosine;

106-212 parts of 2, 2-dimethylolpropionic acid;

194-388 parts of a melting point reducing assistant;

93-370 parts of maleic diethanol amide;

5-30 parts of an acidic catalyst;

5-30 parts of an emulsifier;

600-2000 parts of water.

In the present invention, all the raw material components are commercially available products well known to those skilled in the art unless otherwise specified.

In the invention, the components for preparing the synthetic fat liquor comprise 353-706 parts by weight of N-oleoyl sarcosine, preferably 400-600 parts by weight of N-oleoyl sarcosine. In the present invention, the N-oleoyl sarcosine is a fat-liquoring ingredient.

In the invention, the synthetic fat liquor comprises 106-212 parts of 2, 2-dimethylolpropionic acid, preferably 150-200 parts by weight of N-oleoyl sarcosine.

In the invention, the synthetic fat liquor comprises 194-388 parts of melting point reducing auxiliary agent, preferably 250-300 parts by weight of N-oleoyl sarcosine. In the invention, the melting point reducing auxiliary agent is preferably a eutectic solvent formed by choline chloride and urea; the mol ratio of the choline chloride to the urea is preferably 1: 1-3, and more preferably 1: 1. In the invention, the melting point reducing auxiliary agent can reduce the melting point of the 2, 2-dimethylolpropionic acid, so that the 2, 2-dimethylolpropionic acid can react better and has a certain moisture-keeping effect.

In the invention, the molar ratio of the melting point reducing assistant to the 2, 2-dimethylolpropionic acid is preferably 1:1, and the eutectic structure can be better formed by the melting point reducing assistant and the 2, 2-dimethylolpropionic acid at the molar ratio.

In the invention, the synthetic fat liquor comprises 93-370 parts of maleic diethanol amide, preferably 100-200 parts of N-oleoyl sarcosine by weight. In the invention, the maleic diethanol amide is preferably prepared by reacting maleic anhydride and diethanol amine according to the molar ratio of 1:1 at the temperature of below 40 ℃ for 2-4 hours.

In the invention, the molar ratio of the N-oleoyl sarcosine, the 2, 2-dimethylolpropionic acid and the maleyl diethanol amine is preferably (1-2): 1-4, and more preferably 2:2: 1. The invention limits the dosage ratio to be beneficial to reducing the melting point of the 2, 2-dimethylolpropionic acid.

In the invention, the synthetic fat liquor comprises 5-30 parts of acidic catalyst, preferably 10-20 parts of acidic catalyst, based on the weight parts of the N-oleoyl sarcosine. In the present invention, the acidic catalyst is preferably p-toluenesulfonic acid, a solid acid catalyst or concentrated sulfuric acid; the mass concentration of the concentrated sulfuric acid is preferably 98%. In the present invention, the solid acid catalyst preferably comprises SiO₂-Al₂O₃Catalyst or B₂O₃-Al₂O₃A catalyst.

In the invention, the synthetic fat liquor comprises 5-30 parts of emulsifier, preferably 10-15 parts of emulsifier by weight based on the weight of the N-oleoyl sarcosine. In the present invention, the emulsifier is preferably a nonionic surfactant or an anionic surfactant. In the invention, the nonionic surfactant preferably comprises fatty alcohol polyoxyethylene ether, fatty amine polyoxyethylene ether and sorbitan polyoxyethylene ether; the anionic surfactant preferably comprises fatty alcohol polyoxyethylene ether.

In the invention, the synthetic fat liquor is prepared by taking the weight parts of the N-oleoyl sarcosine as a reference, wherein the synthetic fat liquor comprises 600-2000 parts of water, and preferably 750-1500 parts. In the present invention, the water is preferably distilled water.

The invention also provides a preparation method of the synthetic fat liquor in the technical scheme, which comprises the following steps:

mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid;

mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst to perform a first esterification reaction to obtain a first reactant;

mixing the first reactant and the maleic diethanol amide to perform a second esterification reaction to obtain a second reactant;

and mixing the second reactant with an emulsifier and water to obtain the synthetic fat liquor.

According to the invention, all raw material components except water are dried to be anhydrous preferably before the synthetic fat liquor is prepared. In a specific embodiment of the present invention, when the acidic catalyst is concentrated sulfuric acid, drying is not required. In the invention, the drying temperature is preferably 90-150 ℃, and more preferably 105-110 ℃. The invention can prevent hydrolysis and influence reaction speed and yield by removing water in raw materials.

The 2, 2-dimethylolpropionic acid and the melting point reducing auxiliary agent are mixed and heated to be melted to obtain the liquid 2, 2-dimethylolpropionic acid. In the invention, the heating and melting temperature is preferably 20-50 ℃, and more preferably 30-40 ℃. The melting point of the 2, 2-dimethylolpropionic acid can be reduced by using the melting point reducing auxiliary agent, and the 2, 2-dimethylolpropionic acid can be melted into liquid at a lower temperature.

After the liquid 2, 2-dimethylolpropionic acid is obtained, the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst are mixed for a first esterification reaction to obtain a first reactant. In the invention, the temperature of the first esterification reaction is preferably 100-200 ℃, and more preferably 120-180 ℃; the time of the first esterification reaction is preferably 2-5 h, and more preferably 3-5 h. In the first esterification reaction process, N-oleoyl sarcosine and 2, 2-dimethylolpropionic acid form an esterified product.

After the first reactant is obtained, the first reactant and the maleic acid diethanol amine are mixed for a second esterification reaction to obtain a second reactant. In the invention, the temperature of the second esterification reaction is preferably 100-200 ℃, and more preferably 120-180 ℃; the time of the second esterification reaction is preferably 2-5 h, and more preferably 3-4 h. In the second esterification reaction process, the first reactant and the maleic diethanol amine form an esterified product.

After the second reactant is obtained, the second reactant is mixed with the emulsifier and water to obtain the synthetic fat liquor. Before the second reactant is mixed with the emulsifier and water, the temperature of the second reactant is preferably reduced to 60-80 ℃, so that high-temperature water is prevented from forming water vapor, and the second reactant is not easy to emulsify. In the present invention, the method for mixing the second reactant with the emulsifier and the water preferably comprises: the second reactant and the emulsifier are first mixed and then water is added for second mixing. In the invention, the first mixing is preferably carried out under stirring conditions, and the stirring speed during the first mixing is preferably 50-300 rpm, and more preferably 80-160 rpm; the stirring time in the first mixing is preferably 0.5 to 1.5 hours, and more preferably 1 hour. In the present invention, the first mixing is preferably performed under a stirring condition, and the stirring speed in the second mixing is preferably 500 to 5000rpm, and more preferably 1000 to 3000 rpm; the stirring time during the second mixing is preferably 0.5-3 h, and more preferably 1-2 h. According to the invention, the emulsifier is mixed with the second reactant, and the fatliquoring component can be fully emulsified by adding water to form an emulsion product.

The invention also provides another preparation method of the synthetic fat liquor in the technical scheme, which comprises the following steps:

mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid;

mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst, and carrying out a first esterification reaction to obtain a first product;

mixing maleic diethanol amine and an acidic catalyst, and carrying out a third esterification reaction to obtain a second product;

mixing the second product and the first product, and performing a fourth esterification reaction to obtain a third product;

and mixing the third product with an emulsifier and water to obtain the synthetic fat liquor.

In the method, the maleic diethanol amine is subjected to esterification reaction to form a dendritic esterified substance, and then the dendritic esterified substance is reacted with the first product to obtain the synthetic fat liquor, wherein the structure of the synthetic fat liquor is different from that of the synthetic fat liquor obtained by the first preparation method.

According to the invention, all raw material components except water are dried to be anhydrous preferably before the synthetic fat liquor is prepared. In the invention, the drying temperature is preferably 90-150 ℃, and more preferably 105-110 ℃. The invention can prevent hydrolysis and influence reaction speed and yield by removing water in raw materials.

Mixing 2, 2-dimethylolpropionic acid and a melting point reducing auxiliary agent, and heating and melting to obtain liquid 2, 2-dimethylolpropionic acid; and mixing the liquid 2, 2-dimethylolpropionic acid, N-oleoyl sarcosine and an acidic catalyst to perform a first esterification reaction to obtain a first product. In the present invention, the preparation process of the first product is preferably identical to the preparation process of the first reactant, which is not described herein again.

The maleic diethanol amide and the acidic catalyst are mixed to carry out the third esterification reaction, so as to obtain a second product. In the invention, the temperature of the third esterification reaction is preferably 100-200 ℃, and more preferably 120-130 ℃; the time of the first esterification reaction is preferably 2-5 h, and more preferably 3-4 h. In the second esterification reaction process, the maleic diethanol amine reacts with itself to form a product with high branching degree.

After the first product and the second product are obtained, the second product and the first product are mixed to carry out a fourth esterification reaction, and a third product is obtained. In the invention, the temperature of the fourth esterification reaction is preferably 100-200 ℃, and more preferably 120-130 ℃; the fourth esterification reaction time is preferably 2-5 h, and more preferably 3-4 h. In the fourth esterification reaction process, the first product and the second product further form an esterified product having a branched chain structure.

After the third product is obtained, the third product is mixed with the emulsifier and water to obtain the synthetic fat liquor. Before the third product is mixed with the emulsifier and water, the temperature of the third product is preferably reduced to 60-80 ℃, so that high-temperature water is prevented from forming water vapor, and the third product is not easy to emulsify. In the present invention, the method for mixing the third product with the emulsifier and water preferably comprises: the third product and the emulsifier are first mixed and then water is added for a second mixing. In the invention, the first mixing is preferably carried out under stirring conditions, and the stirring speed during the first mixing is preferably 50-300 rpm, and more preferably 80-160 rpm; the stirring time in the first mixing is preferably 0.5 to 1.5 hours, and more preferably 1 hour. In the present invention, the first mixing is preferably performed under a stirring condition, and the stirring speed in the second mixing is preferably 500 to 5000rpm, and more preferably 1000 to 3000 rpm; the stirring time during the second mixing is preferably 0.5-3 h, and more preferably 1-2 h. The invention mixes the emulsifier and the third product, and adds water to emulsify the fat-adding component into emulsion product.

The invention also provides the application of the synthetic fat liquor in the technical scheme or the synthetic fat liquor prepared by the preparation method in the technical scheme in leather fat liquor. In the invention, the usage amount of the amphoteric synthetic fat liquor is preferably 1-20% of the tare weight, and more preferably 10%. The invention has no special requirements on the specific method of the application, and the leather greasing process is carried out according to the conventional leather greasing procedure in the field.

In the invention, the synthetic fat liquor can be used as leather fat liquor alone or in combination with other types of fat liquor. When the synthetic fatliquor provided by the invention is used in combination with other types of fatliquors, the other types of fatliquors preferably comprise one or more of sulfated fatliquor, sulfited fatliquor, neutral fat and mineral oil; the proportion of each fatting agent has no special requirement when the compound is used, and the fatting agent is determined according to actual requirements.

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Drying the materials except water until no moisture exists;

adding 106 parts by weight of 2, 2-dimethylolpropionic acid and 194 parts by weight of melting point reducing additive into a reactor, heating to 40 ℃, and stirring until the 2, 2-dimethylolpropionic acid and the melting point reducing additive are completely melted into liquid to obtain liquid 2, 2-dimethylolpropionic acid;

353 parts of N-oleoyl sarcosine and 10 parts of p-toluenesulfonic acid are added into the liquid 2, 2-dimethylolpropionic acid, and esterification reaction is carried out for 3 hours at 120 ℃ to obtain a first reactant;

adding 93 parts of maleic diethanol amide into the first reactant, and carrying out esterification reaction for 3 hours at 120 ℃ to obtain a second reactant;

and cooling the second reactant to 60 ℃, adding 10 parts of heterogeneous lauryl polyoxyethylene ether serving as an emulsifier, stirring at the rotating speed of 80rpm for 1 hour, adding 750 parts of distilled water, and stirring at the rotating speed of 1000rpm for 1 hour to obtain the synthetic fat liquor.

Example 2

Drying the materials except water until no moisture exists;

adding 106 parts by weight of 2, 2-dimethylolpropionic acid and 194 parts by weight of melting point reducing additive into a reactor, heating to 40 ℃, and stirring until the 2, 2-dimethylolpropionic acid and the melting point reducing additive are completely melted into liquid to obtain liquid 2, 2-dimethylolpropionic acid;

353 parts of N-oleoyl sarcosine and a solid acid catalyst (specifically SiO) are added into the liquid 2, 2-dimethylolpropionic acid₂-Al₂O₃)20 parts of the raw materials are subjected to esterification reaction for 5 hours at 180 ℃ to obtain a first product;

adding 370 parts of maleic diethanol amide and 15 parts of p-toluenesulfonic acid into another reaction kettle, and carrying out esterification reaction for 2 hours at 100 ℃ to obtain a second product;

adding the second product into the first product, and continuing to perform esterification reaction for 4 hours to obtain a third product;

and cooling the third product to 80 ℃, adding 15 parts of emulsifier fatty amine polyoxyethylene ether, stirring at the rotating speed of 160rpm for 1 hour, adding 1500 parts of distilled water, and stirring at the rotating speed of 3000rpm for 1 hour to obtain the synthetic fat liquor.

Comparative example 1

Anion fatliquoring agent LUTAPOL GLH, produced by Qinheimiao chemical Co., Ltd.

Comparative example 2

Cation fatting agent BUXOM EZ, produced by Qiheli chemical Co., Ltd.

Application example

Taking three same parts of cowhide wet leather, softening, retanning with chromium, neutralizing, retanning and performing conventional process operation, draining, then entering a greasing procedure, respectively adding the synthetic greasing agent described in example 1, the anionic greasing agent in comparative example 1 and the cationic greasing agent in comparative example 2, wherein the addition amounts of the synthetic greasing agents, the anionic greasing agents and the cationic greasing agents are 10% of the weight of the leather, treating in a rotary drum for 1.5 hours, heating to 50 ℃, then adding formic acid with the weight of 1.2% of the weight of the leather for fixation, finally washing with water, performing vacuum drying, and testing the performance of the leather, wherein the results are shown in Table:

TABLE 1 greasing Effect of examples 1-2 and comparative examples 1-2

Fatting agent	Softness	A rate of thickening%	Tear resistance, N	Absorption rate%
					Example 1	2.633	46.4	66.54	95
Example 2	2.597	45.6	66.12	94
					Comparative example 1	2.126	20.7	62.17	86
Comparative example 2	2.303	29.3	63.20	75

The softness is tested by a leather softness tester DY-4023, the thickening rate is tested by a leather thickness tester XK-3054, the calculation method is the ratio of the thickness difference between the leather greased and the blue wet leather thickness to the blue wet leather thickness, the tearing resistance is tested by an electronic tensile tester WDW-50M, and the absorption rate is calculated by the change of COD in the greasing liquid when the greasing starts and ends.

As can be seen from Table 1, the leather treated by the amphoteric synthetic fat liquor provided by the invention can improve the softness, thickening rate, tearing resistance and absorption rate of the leather. The amphiprotic synthetic fat liquor provided by the invention is easier to be absorbed by leather, can endow the leather with good softness and comfortable hand feeling, and is beneficial to improving the mechanical property of the leather.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.