Preparation method of aqueous polyurethane for middle-high-density fiberboard

Abstract

The invention relates to a preparation method of aqueous polyurethane for a middle-high-density fiberboard. The preparation method comprises the steps of synthesis of a hydrophilic polyurethane prepolymer and blending and modifying of low-molecular-weight amino resin, wherein the hydrophilic polyurethane prepolymer comprises the following components in percentage by weight: 8-15% of polyester polyol, 40-60% of isocyanate a, 1.5-6% of hydrophilic chain extender, 0.5-3% of catalyst, 10-25% of isocyanate b, 0.5-3% of amino silane coupling agent and 4-10% of neutralizer. According to the aqueous polyurethane prepared by utilizing the preparation method, a -NCO group in the resin is reasonably closed; and due to the introduction of MUF (melamine-modified urea formaldehyde) resin, a microstructure of the resin is improved, the molecular weight of the aqueous polyurethane is reduced and the stability of the resin is improved. The aqueous polyurethane is synthesized by utilizing manners of inner-crosslikining and blending dual-modifying, the cost is much lower than that of the commercially available PMDI (polydiphenylmethane diisocyanate) resin, and the pressed fiberboard can meet emission loads of formaldehyde and VOC (volatile organic compounds) in export requirements of automotive trims.

Description

technical field [0001] The invention relates to a water-based polyurethane and a preparation method thereof, in particular to an environmentally friendly and non-toxic water-based polyurethane for medium and high-density fiberboard production and a preparation method thereof, belonging to the field of wood-based panel adhesives. Background technique [0002] Due to its excellent performance, easy processing and moderate price, medium and high density fiberboard has been favored by people. With the advancement of science and technology, the continuous emergence and improvement of derivative series products and deep-processing varieties of fiberboard, all kinds of fiberboard will be more and more widely used in various fields of the national economy. [0003] Fibreboard production is inseparable from adhesives. At present, urea-formaldehyde resin glue accounts for more than 90% of the total amount of adhesives used in fiberboard production, but the fatal defect of urea-formal...

AI Technical Summary

Problems solved by technology

[0010] The purpose of the present invention is to provide a method for preparing water-based polyurethane for medium and high-density fiberboard, aiming at the environmental problems caused by the release of formaldehyde in the production of fiberboard, and the problem of board function defects caused by poor waterproof and moisture-proof effects of products. In the production of fiberboard, it can produce products that meet the Japanese F**** level, the US CARB certification Ш stage, and the European standard E 0 Grade formaldehyde release requirements, waterproof and moisture-proof panels required for indoor and outdoor

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