Polyurethane adhesive and preparation method thereof

Abstract

The invention provides a polyurethane adhesive and a preparation method thereof. The polyurethane adhesive comprises diphenylmethane diisocyanate, styrene grafted polyether polyol, epoxide resin, methyl p-toluenesulfonate, polypropylene glycol, polyoxypropylene pentaerythritol ester, an amine catalyst, isophorone diamine, zeolite, castor oil, N-ethyl-N-zinc phenyl dithiocarbamate, resorcinol, triphenylphosphine, a silane coupling agent and an emulsifying agent. The preparation method comprises the following steps of: firstly mixing the diphenylmethane diisocyanate, the amine catalyst, the epoxide resin, the methyl p-toluenesulfonate, the polypropylene glycol, the polyoxypropylene pentaerythritol ester and the zeolite, and then adding the resorcinol and the triphenylphosphine; stirring, and then adding a mixture of the styrene grafted polyether polyol, the isophorone diamine, the castor oil, the N-ethyl-N-zinc phenyl dithiocarbamate, the silane coupling agent and the emulsifying agent to obtain the polyurethane adhesive. The polyurethane adhesive provided by the invention has the advantages of excellent yellowing resistance, ageing resistance, heat resistant property, hydrolysis resistant property and bonding strength.

Description

technical field [0001] The invention belongs to the technical field of adhesives, and in particular relates to a polyurethane adhesive and a preparation method thereof. Background technique [0002] Polyurethane (PU) adhesives refer to adhesives containing urethane groups (-NHCOO-) and / or isocyanate groups (-NCO) in their molecular chains. Polyurethane adhesives are mainly divided into two categories: polyisocyanate and polyurethane. According to the way of use, polyurethane adhesives can be divided into one-component and two-component. Isocyanate groups and urethane groups are very polar and chemically active, so they have good chemical adhesion to porous materials (leather, foam, etc.) and materials with smooth surfaces (glass, metal, etc.). Moreover, polyurethane adhesives have the advantages of good flexibility, excellent vibration resistance, impact resistance, wear resistance, and high bonding strength, and are used more and more widely. [0003] Polyurethane adhesiv...

AI Technical Summary

Problems solved by technology

One-component polyurethane adhesives are generally easy to operate, but in the production process, organic solvents are generally added, which does not meet environmental protection requirements; at the same time, one-component polyurethane adhesives are generally blocked by NCO groups, and are easy to mix with moisture in the air during storage. reaction, resulting in crusting, agglomeration, etc., and the storage period is short; in addition, one-component polyurethane adhesives generally do not add catalysts or only add a very small amount of catalysts, so the curing speed is slow, especially in low temperature environments, even 24 hours above to solidify

[0004] The traditional solvent-free two-component polyurethane adhesive does not add organic solvents during production, which meets environmental protection requirements; since the two components are stored separately, the storage period is longer, but after the two components are mixed according to the chemical ratio, the general pot life Too short, especially in the high temperature season, after the glue is mixed, the viscosity increases rapidly, which makes it difficult to use later, and a large amount of glue is scrapped or cannot form a good bond, resulting in a large number of substandard products

Even in the low temperature season, although the pot life is extended, the curing time is also prolonged, which affects the production efficiency of customers. Although the addition of conventional catalysts (organic bismuth, organic tin, amines, etc.) can speed up the curing speed, it also makes the pot life shorter. Very short, affecting later operations

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