阅读说明：本技术 皮革加脂剂及其制备方法 (Leather fatting agent and preparation method thereof ) 是由 余跃 曾运航 石碧 王亚楠 周建飞 于 2021-10-14 设计创作，主要内容包括：本发明属于皮革助剂技术领域,公开了皮革加脂剂及其制备方法。本发明的皮革加脂剂中水杨酸和抗氧化剂形成协同增效的抗氧化体系,与改性天然油脂混合后能够显著提升加脂剂的抗氧化性能,与现有技术使用的单一抗氧化剂相比,具有更高效和更持久的抗氧化活性。水杨酸的加入大幅提升了抗氧化剂的抗氧化活性,使得少量的抗氧化剂即可赋予加脂剂优良的氧化稳定性,有效地降低了抗氧化皮革加脂剂的生产成本。采用较低用量的抗氧化剂即可制得性能优良的抗氧化加脂剂,与现有技术使用的抗氧化剂用量相比,显著降低了加脂剂的生产成本。(The invention belongs to the technical field of leather additives, and discloses a leather fatting agent and a preparation method thereof. In the leather fatliquor, salicylic acid and an antioxidant form a synergistic antioxidant system, the antioxidant performance of the fatliquor can be obviously improved after the salicylic acid and the antioxidant are mixed with modified natural oil, and compared with a single antioxidant used in the prior art, the leather fatliquor has more efficient and more durable antioxidant activity. The addition of the salicylic acid greatly improves the antioxidant activity of the antioxidant, so that a small amount of the antioxidant can endow the fatting agent with excellent oxidation stability, and the production cost of the antioxidant leather fatting agent is effectively reduced. The antioxidant fatting agent with excellent performance can be prepared by adopting a low dosage of antioxidant, and compared with the dosage of the antioxidant used in the prior art, the production cost of the fatting agent is obviously reduced.)

1. The leather fatting agent is characterized in that raw materials comprise modified natural grease, an antioxidant and salicylic acid, wherein the weight of the antioxidant accounts for 0.1-0.4 wt% and the weight of the salicylic acid accounts for 0.05-0.15 wt% of the weight of the modified natural grease.

2. Leather fatliquor according to claim 1, characterised in that the antioxidant is a fat-soluble antioxidant.

3. Leather fatliquor according to claim 1 or 2, characterised in that the antioxidant comprises, but is not limited to, any of 2, 6-di-tert-butyl-p-cresol, tert-butyl-4-hydroxyanisole and ascorbyl palmitate.

4. The leather fatliquor of claim 1, wherein the modified natural oil comprises, but is not limited to, any one or more of soy phospholipids, oxidized-sulfited fish oils, sulfated rape oil, sulfonated rape oil, and phosphated castor oil.

5. A process for preparing a leather fatliquor according to any one of claims 1 to 4, comprising the steps of:

mixing the modified natural oil, antioxidant and salicylic acid, and stirring at 35-50 deg.C for 0.5-3 hr.

Technical Field

The invention relates to the technical field of leather additives, in particular to a leather fatting agent and a preparation method thereof.

Background

The greasing of leather refers to the treatment of leather with greasing agent, which is to wrap grease on the surface of leather fibers through physical adsorption and chemical combination, form a layer of oil film with lubricating effect between the fibers, make the fibers in a separated state, and increase the mutual mobility of the fibers, thereby endowing the leather with good physical and sensory properties. Natural animal and vegetable fats and their chemically modified products are the most commonly used leather fatliquoring agents because they impart specific oil-like feel, feel and physical properties to leather. However, the fat-liquoring agent for the natural oil leather contains a large amount of unsaturated double bonds, so that the fat-liquoring agent is easy to oxidize and rancidity under the action of light, heat, metal ions and the like, the 'oily clam smell' is generated, even the content of volatile organic matters and Cr (VI) in the leather exceeds the standard, and the quality of the leather is greatly reduced. The antioxidant is added to interrupt the free radical chain reaction generated in the oxidation process of the fatliquor, and the method is an effective way for improving the oxidation stability of the fatliquor.

The literature (Tangyun, Liuhuyun, Kongjia, etc., research on the oxidation resistance of oleic acid by vegetable tannin, Chinese leather 2013, 42(1): 23-25) reports a method for inhibiting the oxidation of oleic acid by using vegetable tannin as an antioxidant. The method has the problems that the fat solubility of the plant tannin is weak, so that the effect of inhibiting the oxidation of the fatting agent is poor, 20 wt% of the plant tannin is required to generate a good oxidation resistance effect, and the application cost is extremely high. The literature (Chenshikun, Rotao, Pengbiuyu, etc., influence of typical antioxidants on the performance of soybean phospholipid fatliquoring agents, leather science and engineering, 2021, 31(4): 27-34) reports a method for inhibiting the oxidation of soybean phospholipid by using fat-soluble antioxidants such as tert-butyl-4-hydroxyanisole and 2, 6-di-tert-butyl-p-cresol. The method has the problems that the efficacy of the antioxidant is still low, and at least 3 wt% of the antioxidant needs to be adopted to produce a good antioxidant effect, so that the production cost of the fatliquor is high. The reason why the above-mentioned antioxidants exhibit low performance in the fatliquoring agent is that modified natural oils generally contain a trace amount of Cu due to corrosion problems of reaction equipment during the preparation process²⁺And Fe³⁺And metal ions are generated, and the metal ions can catalyze the grease molecules to form peroxide free radicals, and the peroxide free radicals further react with the grease molecules to form hydroperoxide and new free radicals to cause chain reaction. Therefore, more antioxidant is consumed to block the chain reaction of the free radicals.

Disclosure of Invention

In order to overcome the defects of large consumption of antioxidant and high production cost of the antioxidant fatliquor in the prior art, the invention aims to provide the leather fatliquor which is low in cost and good in antioxidant effect.

The second purpose of the invention is to provide a preparation method of the leather fatliquor.

In order to achieve the above purpose, the first technical scheme adopted by the invention is as follows:

the leather fatting agent comprises raw materials of modified natural grease, an antioxidant and salicylic acid, wherein the weight of the antioxidant accounts for 0.1-0.4 wt% and the weight of the salicylic acid accounts for 0.05-0.15 wt% of the modified natural grease.

Further, the antioxidant is a fat-soluble antioxidant.

Further, the antioxidant includes, but is not limited to, any one of 2, 6-di-tert-butyl-p-cresol, tert-butyl-4-hydroxyanisole and ascorbyl palmitate.

Further, the modified natural oil and fat includes, but is not limited to, any one or more of soybean phospholipids, oxidized-sulfited fish oil, sulfated rape oil, sulfonated rape oil and phosphated castor oil.

The second technical scheme adopted by the invention is as follows:

a method of preparing a leather fatliquor comprising the steps of:

mixing the modified natural oil, antioxidant and salicylic acid, and stirring at 35-50 deg.C for 0.5-3 hr.

Compared with the prior art, the invention has the following beneficial effects:

(1) in the leather fatliquor, salicylic acid and an antioxidant form a synergistic antioxidant system, the antioxidant performance of the fatliquor can be obviously improved after the salicylic acid and the antioxidant are mixed with modified natural oil, and compared with a single antioxidant used in the prior art, the leather fatliquor has more efficient and more durable antioxidant activity.

(2) The leather fatting agent of the invention has obvious synergistic effect on the antioxidant due to the introduction of the salicylic acid, greatly improves the antioxidant activity of the antioxidant, ensures that a small amount of the antioxidant can endow the fatting agent with excellent oxidation stability, and effectively reduces the production cost of the antioxidant leather fatting agent. The antioxidant fatting agent with excellent performance can be prepared by adopting a lower using amount of antioxidant (0.1-0.4 wt%), and compared with the using amount of the antioxidant (at least 3 wt%) used in the prior art, the production cost of the fatting agent is obviously reduced.

(3) Compared with the existing leather fatliquor, the low-cost and high-efficiency antioxidant fatliquor provided by the invention has stronger oxidation stability and is not easy to be oxidized and deteriorated in the storage and use processes.

(4) Compared with the existing leather fatliquor, the low-cost and high-efficiency antioxidant fatliquor provided by the invention can reduce the risks of the problems of volatile organic compounds, excessive Cr (VI) content and the like generated by the oxidation and deterioration of the fatliquor in finished leather, thereby improving the quality of the finished leather.

Drawings

FIG. 1 is a fatting agent oxidation stability testing device;

FIG. 2 is a graph showing the oxidation stability times of the leather fatliquoring agents of example 1 and comparative examples 1 to 5.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the prior art, the natural oil leather fatting agent is easy to be oxidized and deteriorated because trace Cu is introduced from reaction equipment in the preparation process of the leather fatting agent²⁺And Fe³⁺Plasma metal ions which catalyze the formation of peroxidation of grease moleculesThe free radicals cause chain reaction of the free radicals, and lead the fatting agent to decay. The applicant finds in experiments that the oxidation resistance of the conventional leather fatliquor can be remarkably improved by adding a small amount of salicylic acid into the conventional leather fatliquor, and the principle is as follows: the salicylic acid is a fat-soluble organic acid, can be highly dissolved with the modified natural oil, can fully chelate metal ions in the modified natural oil through hydroxyl and carboxyl after being dissolved, effectively reduces the catalytic action of the metal ions on oil oxidation, and can reduce the antioxidant oxidized by peroxide through phenolic hydroxyl to form a regeneration system of the antioxidant, so that a synergistic system of the salicylic acid and the antioxidant is constructed, the high-efficiency antioxidant effect is finally realized, and the high-efficiency antioxidant leather fatliquor is obtained.

The first embodiment of the invention provides a leather fatliquor, the raw materials comprise modified natural grease, an antioxidant and salicylic acid, wherein the weight of the antioxidant is 0.1-0.4 wt% and the weight of the salicylic acid is 0.05-0.15 wt% based on the weight of the modified natural grease.

As in various embodiments, the weight of the antioxidant can be 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, etc., based on the weight of the modified natural oil; the weight of the salicylic acid can be 0.05 wt%, 0.07 wt%, 0.09 wt%, 0.11 wt%, 0.13 wt%, 0.15 wt%, and the like.

The antioxidant is a fat-soluble antioxidant, namely the antioxidant can be dissolved in the modified natural oil to achieve the effect of the invention. As some preferred embodiments, the antioxidant may include any one of 2, 6-di-t-butyl-p-cresol, t-butyl-4-hydroxyanisole, and ascorbyl palmitate.

In some alternative embodiments, the modified natural oil comprises, but is not limited to, any one or more of soy phospholipids, oxidized-sulfited fish oils, sulfated rape oil, sulfonated rape oil and phosphated castor oil.

The second embodiment of the invention provides a preparation method of a leather fatliquor, which comprises the steps of mixing modified natural oil, an antioxidant and salicylic acid, and stirring for 0.5-3 hours at 35-50 ℃ to obtain the leather fatliquor.

In order to better understand the technical scheme provided by the invention, the leather fatliquor provided by the above embodiment of the invention and the preparation method and performance test thereof are respectively explained by using a plurality of specific examples.

The method for measuring the oxidation stability time of the fatliquor of the leather fatliquor in the specific embodiment and the comparative example of the invention comprises the following steps:

the oxidative stability of the fatliquor was determined using the apparatus shown in FIG. 1. Heating an oil bath kettle to 100 ℃, then weighing 20.0 g of the fatting agent into a sample bottle, accelerating oxidation under the condition of introducing 10L/h of air, monitoring the value of the conductivity of the solution in the absorption bottle in real time by using a conductivity meter during the process, and recording once every 10 min. And (3) drawing a change curve of the conductivity along with time, and obtaining the oxidation stability time of the fatting agent by adopting a hyperbolic curve method. The longer the oxidation stability time, the better the oxidation stability of the fatliquor.

Example 1

Preparing a leather fatliquoring agent:

100 parts of sulfated rape oil, 0.4 part of tert-butyl-4-hydroxyanisole and 0.1 part of salicylic acid are put into a reactor by weight and stirred for 0.5 h at the temperature of 42 ℃ to obtain the leather fatting agent with low cost and high efficiency and oxidation resistance.

The oxidation stability time of the leather fatliquor of the embodiment is 32.6 hours, and the detection result is shown in fig. 2.

Comparative example 1

100 parts of sulfated rape oil and 0.5 part of tert-butyl-4-hydroxyanisole are put into a reactor by weight and stirred for 0.5 h at the temperature of 42 ℃ to obtain the leather fatliquor.

The oxidation stability time of the leather fatliquor of the comparative example was determined to be 24.2 hours, and the test results are shown in fig. 2.

Comparative example 2

100 parts of sulfated rape oil and 0.4 part of tert-butyl-4-hydroxyanisole are put into a reactor by weight and stirred for 0.5 h at the temperature of 42 ℃ to obtain the leather fatliquor.

The oxidation stability time of the leather fatliquor of the comparative example was determined to be 22.4 hours, and the test results are shown in fig. 2.

Comparative example 3

Putting 100 parts of sulfated rape oil and 0.5 part of salicylic acid in parts by weight into a reactor, and stirring for 0.5 h at the temperature of 42 ℃ to obtain the leather fatliquor.

The oxidation stability time of the leather fatliquor of the comparative example was determined to be 18.1 hours, and the test results are shown in fig. 2.

Comparative example 4

Putting 100 parts of sulfated rape oil and 0.1 part of salicylic acid in parts by weight into a reactor, and stirring for 0.5 h at the temperature of 42 ℃ to obtain the leather fatliquor.

The oxidation stability time of the leather fatliquor of the comparative example was determined to be 17.7 hours, and the test results are shown in fig. 2.

Comparative example 5

100 parts of sulfated rape oil is put into a reactor by weight and stirred for 0.5 h at the temperature of 42 ℃ to obtain the leather fatliquor.

The oxidation stability time of the leather fatliquor of the comparative example was determined to be 15.3 hours, and the test results are shown in fig. 2.

The oxidation stabilization time of the fatliquoring agents according to example 1 and comparative examples 1 to 5 can be seen: the fat-liquoring agent of the comparative example 5 only contains the sulfated rape oil, and the oxidation stabilization time is only 15.3 h; comparative example 4 after 0.1 part of salicylic acid was added to the sulfated rape oil, the oxidation stabilization time of the fatting agent was increased to 17.7 h, the amplification of the oxidation stabilization time was 2.4 h; comparative example 2 after 0.4 part of antioxidant was added to the sulfated rape oil, the oxidation stability time of the fatliquor was increased to 22.4 h, with an increase of 7.1 h; example 1 after adding a combination of "0.4 parts antioxidant +0.1 parts salicylic acid" to sulphated rape oil, the oxidation stability time of the fatliquor was as high as 32.6 h, with an increase of 17.3 h. It is noted that the increase in the oxidative stabilization time of the fatliquor of example 1 is already higher than the sum of the increases in the oxidative stabilization times of the fatliquors of comparative example 2 and comparative example 4 (i.e. 17.3 h > (2.4 h + 7.1 h)). In addition, in comparative example 3, after 0.5 part of salicylic acid is added into the sulfated rape oil, the oxidation stability time of the fatting agent is increased to 18.1 h, and the amplification of the oxidation stability time is 2.8 h; comparative example 1 after 0.5 part of antioxidant was added to the sulfated rape oil, the oxidation stability time of the fatliquor was increased to 24.2 h, with an increase of 8.9 h; likewise, the increase in the oxidative stabilization time of the fatliquor of example 1 is still higher than the sum of the increases in the oxidative stabilization times of the fatliquors of comparative example 1 and comparative example 3 (i.e., 17.3 h > (2.8 h + 8.9 h)).

The analysis of the comparative example and the embodiment shows that the combination of the antioxidant and the salicylic acid adopted in the invention has obvious synergistic antioxidant effect, the oxidation stability of the fatliquor can be obviously improved even under low dosage, and the leather fatliquor with low cost and high efficiency of antioxidation is prepared, which is an effect that is difficult to achieve in the prior art. Therefore, the antioxidant combination 'antioxidant + salicylic acid' used in the present invention is a significant improvement over the prior art, and can produce a beneficial antioxidant effect.

Example 2

Preparing a leather fatliquoring agent:

according to the weight portion, 100 portions of soybean lecithin, 0.1 portion of 2, 6-di-tert-butyl-p-cresol and 0.05 portion of salicylic acid are placed in a reactor and stirred for 1.8 hours at the temperature of 35 ℃, and the leather fatting agent with low cost and high efficiency and antioxidation is obtained.

The oxidation stability time of the leather fatliquor in this example was determined to be 25.4 hours.

Example 3

Preparing a leather fatliquoring agent:

putting 100 parts by weight of oxidized-sulfited fish oil, 0.25 part by weight of ascorbyl palmitate and 0.15 part by weight of salicylic acid into a reactor, and stirring for 3 hours at the temperature of 50 ℃ to obtain the low-cost and high-efficiency antioxidant leather fatliquor.

The oxidation stability time of the leather fatliquor in this example was determined to be 28.6 h.

Example 4

Preparing a leather fatliquoring agent:

100 portions of sulfated castor oil, 0.05 portion of tertiary butyl-4-hydroxyanisole, 0.05 portion of 2, 6-ditert-butyl-p-cresol and 0.15 portion of salicylic acid are put into a reactor by weight portion and stirred for 1.8 hours at the temperature of 42 ℃, and the leather fatting agent with low cost and high efficiency and oxidation resistance is obtained.

The oxidation stability time of the leather fatliquor in this example was determined to be 35.8 hours.

Example 5

Preparing a leather fatliquoring agent:

100 parts of sulfonated rape oil, 0.12 part of 2, 6-di-tert-butyl-p-cresol, 0.12 part of ascorbyl palmitate and 0.1 part of salicylic acid are placed in a reactor and stirred for 0.5 h at the temperature of 50 ℃ to obtain the low-cost and high-efficiency antioxidant leather fatliquor.

The oxidation stability time of the leather fatliquor in this example was determined to be 30.7 hours.

Example 6

Preparing a leather fatliquoring agent:

according to the parts by weight, 50 parts of soybean phospholipid, 50 parts of sulfated rape oil, 0.2 part of ascorbyl palmitate, 0.2 part of tert-butyl-4-hydroxyanisole and 0.05 part of salicylic acid are placed in a reactor and stirred for 3 hours at the temperature of 35 ℃ to obtain the low-cost and high-efficiency antioxidant leather fatliquor.

The oxidation stability time of the leather fatliquor in this example was determined to be 29.9 h.

Example 7

Preparing a leather fatliquoring agent:

according to parts by weight, 50 parts of oxidized-sulfited fish oil, 50 parts of sulfated castor oil, 0.08 part of 2, 6-di-tert-butyl-p-cresol, 0.08 part of tert-butyl-4-hydroxyanisole, 0.08 part of ascorbyl palmitate and 0.05 part of salicylic acid are placed in a reactor and stirred for 0.5 h at the temperature of 35 ℃, so that the low-cost and high-efficiency antioxidant leather fatliquor is obtained.

The oxidation stability time of the leather fatliquor in this example was determined to be 33.4 h.

Example 8

Preparing a leather fatliquoring agent:

according to the weight parts, 40 parts of soybean phospholipid, 30 parts of sulfonated rape oil, 30 parts of sulfated castor oil, 0.05 part of 2, 6-di-tert-butyl-p-cresol, 0.05 part of ascorbyl palmitate and 0.05 part of salicylic acid are placed in a reactor and stirred for 3 hours at the temperature of 42 ℃ to obtain the low-cost and high-efficiency antioxidant leather fatliquor.

The oxidation stability time of the leather fatliquor in this example was determined to be 31.9 h.

Example 9

Preparing a leather fatliquoring agent:

according to the weight parts, 25 parts of soybean phospholipid, 25 parts of oxidized-sulfited fish oil, 25 parts of sulfonated rape oil, 25 parts of sulfated castor oil, 0.2 part of 2, 6-di-tert-butyl-p-cresol, 0.2 part of ascorbyl palmitate and 0.1 part of salicylic acid are placed in a reactor and stirred for 1.8 hours at the temperature of 50 ℃ to obtain the low-cost and high-efficiency antioxidant leather fatliquor.

The oxidation stability time of the leather fatliquor in this example was determined to be 38.4 h.

Example 10

Preparing a leather fatliquoring agent:

according to parts by weight, 20 parts of soybean phospholipid, 20 parts of oxidized-sulfited fish oil, 20 parts of sulfated rape oil, 20 parts of sulfonated rape oil, 20 parts of sulfated castor oil, 0.13 part of 2, 6-di-tert-butyl-p-cresol, 0.13 part of tert-butyl-4-hydroxyanisole, 0.13 part of ascorbyl palmitate and 0.15 part of salicylic acid are placed in a reactor and stirred for 3 hours at the temperature of 35 ℃, so that the low-cost and high-efficiency antioxidant leather fatliquor is obtained.

The oxidation stability time of the leather fatliquor in this example was determined to be 37.1 h.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.