Preparation method of high-resilience sagging-sense polyurethane resin used for wet-method synthetic leather

Abstract

The invention relates to a preparation method of high-resilience sagging-sense polyurethane resin used for wet-method synthetic leather. The preparation method includes: a) successively adding polyester polyol, a chain extender, a solvent and a catalyst into a reaction kettle, stirring the components, and controlling the temperature in the reaction kettle to be 40-60 DEG C; b) separating diisocyanate into 3-5 parts and adding the diisocyanate into the reaction kettle at time interval, and performing a reaction under stirring with temperature in the reaction kettle controlled to be not higher than 90 DEG C until the viscosity of the product is 1*10<5>-2*10<5> cps / 25 DEG C, and cooling, packaging and weighing the product, wherein the mass ratio of the polyester polyol, diisocyanate, chain extender, solvent to the catalyst is 1:0.25:0.046:4.19:0.0001. In the method, the diisocyanate is separated into several parts and then is added into the reaction kettle, and temperature in the reaction kettle and viscosity of the product are controlled, so that the produced resin has high resilience. Synthetic leather produced with the resin has soft hand feel, high sagging-sense and high resilience.

Description

technical field [0001] The invention relates to a polyurethane resin, in particular to a preparation method of a high-resilience and drape-feeling polyurethane resin for wet-process synthetic leather. Background technique [0002] Because polyurethane synthetic leather has a number of unique properties that other synthetic materials do not have, its application in human daily life can be seen everywhere, and has penetrated into all aspects of human life, from household items to clothing, shoes, and car interiors. See the application of polyurethane synthetic leather. The traditional polyurethane resin for synthetic leather is synthesized by polyglycol, chain extender, and diisocyanate in a solvent system. Polyglycol is used as a soft segment in the molecular structure, and diisocyanate and chain extender are used as hard segments. The final molecular stacking structure is an aggregate structure with microphase separation of soft and hard segments, and the synergistic effect...

AI Technical Summary

Problems solved by technology

However, it is limited to the limitations of the raw materials of polyurethane resin used in synthetic leather at present, such as the lack of composite performance of a single polyglycol, the orderly and controllable polymerization of composite polyglycol is difficult to achieve, and the polyether glycol polyurethane is not resistant to high temperature and resistant to high temperature. High-temperature polyurethane is not resistant to hydrolysis, etc., and the soft and hard segments of polyurethane molecules must be properly matched to reflect the final excellent performance. Therefore, it is difficult to prepare polyurethane resins with excellent properties

In addition, what is more serious is that the porous structure not only gives the synthetic leather material sensuality and fullness, but also reduces the resilience. Generally, when the thinner pore wall is subjected to continuous force and continuous extrusion, it will produce damage that is difficult to recover. Seriously affect the service life

Although some studies have introduced microsphere expansion agents into polyurethane products or used modifiers to adjust the polymerization sequence of PAPI (polyphenyl polymethylene polyisocyanate) to improve resilience (CN104558510A, CN104479100A), but due to the pores of microsphere expansion agents A series of factors such as the uncontrollability of the type, the heterogeneity of the cells, the limitation and instability of the expansion temperature, and the PAPI functionality is greater than 2, it is difficult to achieve the final molecular structure control, etc., so that the molecular structure can be realized under such circumstances. It is difficult to improve the resilience of polyurethane molecules

Therefore, if the resilience of polyurethane macromolecules is not changed in the molecular structure, it is difficult to substantially change the disadvantage of insufficient resilience of polyurethane synthetic leather under continuous use or load conditions.

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