Patent display(4) Polyurethane surface resin for shoe leather and preparation method thereof

Technical field

The present invention belongs to the field of polyurethane synthetic material technology, specifically relates to a kind of shoe leather polyurethane surface resin and preparation method thereof.

Background

Existing synthetic leather or imitation leather include PU (polyurethane) leather and PVC, PU leather due to its performance is getting closer and closer to natural leather, and good physical and mechanical properties, so that it in the footwear industry to obtain a wide range of applications, with aesthetics, wearing comfort and hygiene and other advantages. However, the existing sneakers still have the disadvantages of poor breathability and poor water absorption, and long-term wearing of feet will feel uncomfortable, wet, burning feet, if it is sweaty feet, it may also lead to serious diseases. The poor breathability and water absorption of polyurethane as its raw materials are the direct cause of the poor properties of synthetic leather.

Contents of the Invention

Purpose of the Invention:In view of the deficiencies present in the prior art, the object of the present invention is to provide a polyurethane surface resin for shoe leather, so that it has good breathability, good water absorption and other characteristics. Another object of the present invention is to provide a method for preparing the polyurethane surface resin for shoe leather.

Technical solutions:In order to achieve the above-described object of invention, the technical solution employed in the present invention is:

A kind of polyurethane surface resin for shoe leather, prepared by the following method: mixing PU, urea and DMF, at room temperature, 3000r / min stirring and mixing can be, wherein the weight ratio of PU, urea and dimethylformamide (DMF) is 100: 10 ~ 15 : 30 ~ 50.

The PU is prepared by the following method: stirring homogeneous polyester polyols, a chain spreader and a portion of dmf, adding diphenylmethane diisocyanate (MDI), 70°C, reaction to viscosity 1.0×106 -1.5×106cps / 25°C, adding the remaining DMF, stirring the reaction for 1h can be;Among them, the weight ratio of polyester polyols, chain extenders, DMF and MDI is 19~20:1.8~2.0: 70:8.1~8.5.

The Polyester Polyol is a copolymer of adipic acid and butylene glycol, with a molecular weight of about 2000.

The chain expander is butylene glycol.

A polyurethane topsizing resin for the preparation of shoe leather, including the following steps:

(1) After stirring the polyester polyol, the chain spreader and part of the DMF, add MDI, 70 °C, the reaction to the viscosity of 1.0× 106 -1.5×106cps/25 °C, add the remaining DMF, stir the reaction for 1h, to obtain PU; Among them, the weight ratio of polyester polyols, chain extenders, DMF and MDI is 19~20:1.8~2.0:70:8.1~8.5;

(2) Mix PU, urea and DMF, at room temperature, 3000r/min stir and mix well, to produce a polyurethane surface resin for shoe leather, of which the weight ratio of PU, urea and DMF is 100: 10 ~ 15 : 30 ~ 50.

In order to meet the synthetic leather has good wet exchange, when making a polyurethane resin, the solvent used is DMF, and then the polyurethane is improved with urea, which is impregnated with PU pulp or scraped on the substrate, solidified by the water bath, due to the good hydrophilicity of DMF, it is quickly replaced by water, so that it is rapidly dissolved with water, so that in the process of solidification of leather PU, leaving countless small holes, which is the principle of permeability of synthetic leather.

Beneficial effects:Compared with the prior art, the shoe leather of the present invention with polyurethane surface resin has outstanding advantages: the resin stability is good, compared with the existing water-absorbent resin mechanically mixed with fillers on the market, can avoid the problem of packing settlement after a long time; The selection of urea, environmentally friendly, economical, decomposed by urea at high temperatures, leaving pinholes on the pu membrane formed, playing a breathable and water-absorbing effect; It has good practicality in the footwear industry and can produce good economic and social benefits.