Aqueous polyurethane dispersoid for synthetic leather adhesive and preparation method thereof

Abstract

The invention discloses an aqueous polyurethane dispersoid for a synthetic leather adhesive and a preparation method thereof. The aqueous polyurethane dispersoid is prepared from A, a polyurethane prepolymer prepared from 10-30wt% of polyisocyanate, 50-85wt% of polyester polyol, 0.1-3wt% of polyoxyalkylene side chain-containing dihydric alcohol, 0.1-5wt% of a low-molecular weight dihydric alcohol chain extender and 0.1-3wt% of hydroxy carboxylic acid, B, 0.1-5wt% of a polyamine chain extender a unsubstituted by an ion group, C, 0-5wt% of a chain extender b substituted by an ion group, and D, 66-100wt% of water. The aqueous polyurethane dispersoid has solid content of 50-60wt%. The synthetic leather adhesive prepared from the aqueous polyurethane dispersoid has good initial adhesion, high peel strength, excellent alkali, solvent and hydrolysis jungle test resistance, and soft handle.

Description

technical field [0001] The invention relates to a water-based polyurethane dispersion, a preparation method thereof, and an application thereof in a synthetic leather adhesive. Background of the invention [0002] my country is a big country in the manufacture of synthetic leather. At present, in the production process of the domestic polyurethane synthetic leather industry, solvent-based polyurethane resin is widely used as the basic raw material for the base layer and surface layer of traditional synthetic leather products. Most of its production processes use toluene, xylene and DMF as solvents, which have a serious impact on the ecological environment. Water-based polyurethane uses water as the medium and does not contain any solvents that can pollute the human body and the environment. Using waterborne polyurethane resin as raw material to manufacture synthetic leather is an effective way to solve the pollution in the synthetic leather industry from the source. Polyur...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent CN 101665675A discloses a preparation method of a water-based polyurethane adhesive and superfine fiber synthetic leather; Due to the problem of poor bonding effect, the mixed MDI system is used instead of pure TDI to prepare, which has better initial viscosity, resilience and higher final strength; the patent does not mention the wet bonding effect, solvent resistance and jungle test results.

However, for the existing water-based adhesives, the initial adhesion is poor, and when the wet lamination process is used, it is easy to cause too much slurry in the base cloth layer, resulting in stiff hand feeling, and the wet lamination process is likely to cause the release paper and the base cloth Displacement between them, resulting in "double eyelids" in the product and the output of unqualified products

When semi-dry pasting is used, it is necessary to grasp the drying time to obtain a better bonding effect, especially in the dry veneer process of superfine fiber base cloth, it is more difficult to grasp the semi-dry pasting process.

At the same time, the existing water-based adhesives are poor in the hydrolysis jungle test, and the bond strength drops significantly in high-temperature and high-humidity environments, which cannot meet the application requirements.

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