Leather isolating layer finishing agent, preparation method thereof, and leather

Abstract

The invention discloses a leather isolating layer finishing agent, a preparation method thereof, and a leather. The preparation method of the leather isolating layer finishing agent comprises the following steps: reacting 10-25 parts of isocyanate, 10-20 parts of diol and 1-3 parts of a hydrophilic chain extender at 70-90 DEG C for 1-4 h, adding 0-5 parts of an organic solvent, cooling the obtained solution to 40-50 DEG C, adding 1-3 parts of an organic alkali and 150-200 parts of water, performing uniform dispersion, then adding 1-2.5 parts of an amine chain extender to extend the chain, andstirring and reacting the obtained solution for 1-2 h to obtain waterborne polyurethane containing an amino group in the terminal group; and taking 40-70 parts of the waterborne polyurethane, adding 30-60 parts of water-based epoxy resin, and stirring and reacting the obtained mixture for 3-5 h. Zero amount or a very small amount of an organic solvent is added in the preparation process of the leather isolating layer finishing agent, so the finishing agent has no irritating smell when sprayed, and has no environmental pollution; and the finishing agent is applied to the leather isolating layerto make the leather isolating layer have good wet squeegee performance and heavy pressure off-board property, and does not stick to the board.

Description

technical field [0001] The invention relates to the technical field of leather manufacturing, in particular to a leather isolation layer finishing agent, a preparation method thereof and leather. Background technique [0002] In the current tanning technology, before the leather softening or embossing process, it is necessary to spray the isolation layer finishing agent to prevent the leather from being polluted by oil, dust and other pollutants during the softening process and the slurry layer in the subsequent process. The adhesion of the resin decreases, causing the upper layer of resin to fall off when the leather meets water, which seriously affects the quality and appearance of the leather. Spraying the isolation layer finishing agent can also prevent the coating from sticking and sticking to the board during the high-temperature embossing process of the leather, which will affect the normal operation of the subsequent process and affect the quality of the leather. Cu...

AI Technical Summary

Problems solved by technology

[0002] In the current tanning technology, before the leather softening or embossing process, it is necessary to spray the isolation layer finishing agent to prevent the leather from being polluted by oil, dust and other pollutants during the softening process and the slurry layer in the subsequent process. The adhesiveness of the resin decreases, causing the upper layer of resin to fall off when the leather meets water, which seriously affects the quality and appearance of the leather

Spraying the isolation layer finishing agent can also prevent the coating from sticking and sticking to the board during the high-temperature embossing process of the leather, which will affect the normal operation of the subsequent process and affect the quality of the leather

Currently, the coating agents for leather isolation layers used in the market are almost all nitrocellulose emulsions, and nitrocellulose emulsions are white powders that are insoluble in water. Therefore, nitrocellulose emulsions contain a large amount of organic solvents, and the amount of organic solvents exceeds the total mass of nitrocellulose emulsions. 45%, the nitrocellulose emulsion has a strong pungent smell, resulting in high VOC content (> 450g / L), and such a large amount of organic solvents volatilize into the air, which will have adverse effects on operators and working environment, and also It will cause serious pollution to the natural environment and does not meet the current environmental protection requirements

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