High initial strength reaction type polyurethane hot melt adhesive and preparation method thereof

Abstract

The invention discloses a high initial strength reaction type polyurethane hot melt adhesive and a preparation method thereof. The hot melt adhesive is prepared from the following raw materials in parts by weight: 60-90 parts of polyhydric alcohols, 5-40 parts of tackifying resins, 10-15 parts of isocyanate compounds, 0.1-1 part of catalyst and 0.1-1 part of adhesion promoter. The preparation method comprises the following steps: (1) adding polyhydric alcohols and tackifying resins into a reaction vessel, heating in vacuum, melting and dehydrating, thereby acquiring a mixture; (2) adding isocyanate compounds or isocyanate group terminated prepolymer compounds into the mixture acquired in the step (1) and then controlling temperature and performing polymerization reaction, thereby acquiringa polymer; (3) adding a catalyst and an adhesion promoter into the polymer acquired in the step (2), controlling temperature and reacting in vacuum; and (4) placing the prepared hot melt adhesive into a container and filling dry inert gas. The high initial strength reaction type polyurethane hot melt adhesive disclosed by the invention has the advantages of high initial strength, excellent temperature resistance and low production cost. The preparation method is simple and is easy for industrial production.

Description

technical field [0001] The invention belongs to the technical field of reactive polyurethane hot melt adhesives, in particular to a high initial strength reactive polyurethane hot melt adhesive and a preparation method thereof. Background technique [0002] Moisture-curing polyurethane hot-melt adhesive, referred to as PUR, is solid at room temperature and does not contain solvent plasticizers. When in use, it is heated to make it liquid and immediately applied to the surface of the adherend, and then attached to another adherend. When the adhesive is cooled and solidified, the isocyanate reacts with the moisture on the surface of the adherend or the moisture in the air to extend the chain into a polymer compound, thereby producing an adhesive force. [0003] With the development of industrial automation, the production rhythm of the assembly line is accelerated. It is required that the adhesive surface can be bonded faster and firmer, and the gluing should be smooth and fas...

AI Technical Summary

Problems solved by technology

However, high-strength double-sided adhesive tape needs manual bonding, which is inefficient and poor in final strength; solvent-based adhesives emit a large amount of volatile organic compounds and need to be dried, causing serious pollution and high energy consumption; although water-based adhesives are environmentally friendly products, However, drying consumes a lot of energy and has low efficiency. Other electronic components may be affected during drying, which cannot meet the production rhythm of an automated assembly line.

[0004] It can be seen that although the traditional PUR can provide a certain initial strength after cooling, the PUR sold in the general market needs to be kept for more than 2 hours when used, which can no longer meet the requirements of rapid assembly, seriously affecting production efficiency and increasing production costs.

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