阅读说明：本技术 一种植物油衍生物改性的两性聚氨酯复鞣剂及其制备方法 (Vegetable oil derivative modified amphoteric polyurethane retanning agent and preparation method thereof ) 是由 王学川 蓝晓梅 刘新华 朱兴 韩庆鑫 王园园 于 2020-07-28 设计创作，主要内容包括：发明本公开了一种植物油衍生物改性两性聚氨酯复鞣剂及其制备方法,首先将二异氰酸酯、聚四氢呋喃二醚醇和催化剂混合均匀进行预聚反应,升温后先后加入阴离子扩链剂2,2-二羟甲基丙酸,阳离子扩链剂<I>N</I>-甲基二乙醇胺,再将蓖麻油酸加入到体系中反应一定的时间后,降温进行中和,乳化,最后得到蓖麻油酸改性两性聚氨酯复鞣剂。本发明提供的蓖麻油酸改性的两性聚氨酯复鞣剂中同时含有阴、阳离子基团,可有效提高无铬鞣特别是有机无铬鞣制坯革或者毛皮对皮革化料的吸收率,进而改善无铬鞣皮革和毛皮的耐湿热稳定性、手感、撕裂强度等性能。(Invention of the inventionThe vegetable oil derivative modified amphoteric polyurethane retanning agent is prepared through the first mixing diisocyanate, polytetrahydrofuran diether alcohol and catalyst for pre-polymerization reaction, the subsequent heating and adding anionic chain extender 2, 2-dimethylolpropionic acid and cationic chain extender successively N And (2) adding ricinoleic acid into the system, reacting for a certain time, cooling, neutralizing, and emulsifying to obtain the ricinoleic acid modified amphoteric polyurethane retanning agent. The ricinoleic acid modified amphoteric polyurethane retanning agent provided by the invention contains anionic and cationic groups, so that the absorptivity of chrome-free tanning, particularly organic chrome-free tanning crust leather or fur, on leather chemicals can be effectively improved, and the properties of the chrome-free tanning leather and fur, such as wet-heat resistance stability, hand feeling, tearing strength and the like, are further improved.)

1. A preparation method of vegetable oil derivative modified amphoteric polyurethane retanning agent is characterized by comprising the following steps:

1) mixing isocyanate and polytetrahydrofuran diether alcohol at the temperature of 60-90 ℃, and reacting to obtain a polyurethane prepolymer;

2) heating to 80-100 ℃, and respectively adding 2, 2-dimethylolpropionic acid andN-methyldiethanolamine chain extension; after the chain extension reaction is finished, adding ricinoleic acid for reaction;

3) cooling, adding triethylamine for neutralization, and finally adding distilled water for high-speed stirring and emulsification.

2. The method of claim 1, wherein the isocyanate, polytetrahydrofuran diether alcohol, 2-dimethylolpropionic acid, and the like,NThe molar ratio of the methyl diethanol amine to the ricinoleic acid is 16:5 (3-3.5) to (3-4) to (2-3).

3. The method of claim 1, wherein the isocyanate is one of diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI, isophorone diisocyanate IPDI.

4. The method of claim 1, wherein the reaction temperature is 60 to 90 ℃ and the reaction time is 2 to 4 hours when preparing the polyurethane prepolymer; during chain extension, the reaction temperature is 80-100 ℃, and the reaction time is 2-4 h; adding ricinoleic acid, and reacting at the temperature of 80-100 ℃ for 2-4 h; reaction system is N₂Under protection.

5. A vegetable oil derivative-modified amphoteric polyurethane retanning agent obtained by the method according to any one of claims 1 to 4.

Technical Field

The invention relates to the technical field of leather retanning agents, in particular to an amphoteric polyurethane retanning agent modified by vegetable oil derivatives and a preparation method thereof.

Background

Currently, the chrome tanning process most commonly used in the leather industry has serious pollution problems. Therefore, the development of chromium-free ecological leather manufacturing technologies such as non-chromium metal tanning and non-metal tanning is a future development direction of the leather industry. However, compared to chrome-tanned fibers, non-metal tanned fibers are strongly negatively charged and lack positively charged metal ions to ionize their surface, thus reducing the reactivity of the non-metal tanned leather fibers with conventional anionic agents for leather. Therefore, the research on the leather retanning agent capable of improving the isoelectric point of the non-metal tanned crust leather is the main work of researchers at the present stage. At present, researchers develop a non-metal tanning agent for chrome-free tanning of leather, and the retanning agent researched by the invention is a matched retanning agent of the tanning agent.

Polyurethanes are themselves useful in leather retanning, and are mostly of a single anionic or cationic nature when used in leather and fur retanning. The amphoteric polyurethane contains anions and cations, has strong acid and alkali resistance and good biodegradability, and can effectively improve the binding rate of subsequent anion materials when being applied to leather and fur retanning processes.

Ricinoleic acid contains hydroxyl and double bonds in molecules, and can be used as a chain extender for polyurethane synthesis. The ricinoleic acid is introduced into the polyurethane, so that the utilization rate of natural renewable resources can be improved, and a certain fat-liquoring effect on leather and fur can be achieved.

Ricinoleic acid is introduced into amphoteric polyurethane and applied to the retanning procedure of leather, and a retanning agent with a fat-liquoring function in the retanning process has no related research yet.

Disclosure of Invention

The invention aims to provide a vegetable oil derivative modified amphoteric polyurethane retanning agent capable of improving the electropositivity of non-metal tanned leather blanks and a preparation method thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is that N is₂Under the condition that the temperature is 60-90 ℃, diisocyanate and polytetrahydrofuran diether alcohol are prepolymerized for 2-3 hours under the action of a catalyst, the temperature is increased to 80-100 ℃, then an anionic chain extender and a cationic chain extender are respectively added into the system to react for 2-4 hours, then a vegetable oil derivative is added to react for 2-4 hours, the temperature is reduced to 40-50 ℃, neutralization and emulsification are carried out, and finally the vegetable oil derivative modified amphoteric polyurethane retanning agent is obtained.

The mass ratio of diisocyanate to polytetrahydrofuran diether alcohol is (2-4) to 1; the mass of the anionic chain extender and the mass of the cationic chain extender are respectively 5-10% of that of the diisocyanate and the polytetrahydrofuran diether alcohol.

Specifically, the method comprises the following steps: in N₂Under the protection of 60-90 ℃, mixing a certain amount of diisocyanate and polytetrahydrofuran diether alcohol, and reacting to obtain a polyurethane prepolymer; heating and adding 2, 2-dimethylolpropionic acid andNcarrying out chain extension reaction on methyl diethanolamine, and adding ricinoleic acid for modification; cooling, adding triethylamine to neutralize carboxyl, finally adding distilled water, stirring at high speed and emulsifying to obtain the ricinoleic acid modified amphoteric polyurethane retanning agent.

Further, the reactant ratio is diisocyanate: polytetrahydrofuran diether alcohol: 2, 2-dimethylolpropionic acid: n-methyldiethanolamine: ricinoleic acid =16:5, (3-3.5), (3-4), (2-3). .

Further, the diisocyanate is any one of diphenylmethane diisocyanate MDI, toluene diisocyanate TDI, hexamethylene diisocyanate HDI and isophorone diisocyanate IPDI.

Further, during chain extension, the reaction temperature is 80-100 ℃, and the reaction time is 2-4 h.

Further, when the ricinoleic acid is added for modification, the reaction temperature is 80-100 ℃, and the reaction time is 2-4 hours.

The invention has the beneficial effects that:

1. ricinoleic acid is introduced into amphoteric polyurethane to synthesize novel amphoteric polyurethane which can be used for leather retanning. The retanning agent contains anionic and cationic groups, so that the isoelectric points of organic chrome-free tanned leather and fur can be effectively improved, the absorption rate of the leather and the fur on a leather finishing material is further improved, and a certain fat-liquoring effect can be achieved.

2. The synthesis route is simple, the reaction temperature is low, the reaction time is short, and the synthesis can be carried out under normal pressure. The product has good biodegradability and can reduce environmental pollution due to the introduction of vegetable oil derivatives.

Detailed Description

The present invention will be described in detail with reference to specific examples, but the present invention is not limited to the following examples.