Moisture-cured silicone modified polyurethane and hot melt adhesive composition and preparation method thereof

Abstract

The invention discloses a moisture-cured silicone modified polyurethane and hot melt adhesive composition. The composition comprises the following raw materials by weight: 60 to 80 percent of silicone modified polyurethane, 10 to 20 percent of tackifying resin, 1 to 8 percent of plasticiser, 0.5 to 2 percent of viscosity reducing additive, 0.2 to 1 percent of organosilicon additive, 3 to 8 percent of inorganic filler, 0.05 to 0.5 percent of anti-oxidant, and 0.05 to 0.5 percent of ultraviolet light absorber. The invention further discloses a preparation method of the composition. The invention has the advantages that the composition can be cross-linked fast and completely; the viscosity, the solidification foaming phenomenon and the bonding performance of a hot melt adhesive system are improved; the purposes of no bubble, no odor, low construction viscosity and the like are realized; the final strength is favorable; and solidification without bubbles can be realized on the condition that a layer is 2 mm in thickness.

Description

technical field [0001] The invention relates to the technical field of adhesives, in particular to a polyurethane hot-melt adhesive composition and a preparation method thereof. Background technique [0002] Hot melt adhesives are solid at room temperature, soften to viscous liquids when heated and can therefore be applied in the form of a melt. The application of the hot melt adhesive is carried out at a temperature above 120° C., typically above 130° C., forming a cure while cooling to room temperature while building the bond strength. Conventional hot melt adhesives are non-reactive adhesives that resoften or melt when heated and are therefore not suitable for use at high temperatures. In addition, conventional hot melt adhesives are often prone to creep (cold flow) at temperatures well below their softening point. [0003] Reactive hot melt adhesives eliminate the above-mentioned defects of traditional non-reactive hot melt adhesives to a large extent by introducing re...

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Problems solved by technology

However, due to the generation of carbon dioxide gas during the crosslinking reaction, the prior art reactive polyurethane hot melt adhesive still has the following technical defects: the air bubbles generated in the adhesive will lead to a reduction in the final strength, so that the bonding strength is not good. High, and affect the adhesion to the substrate; in the case of visible adhesion, such as packaging, it will destroy the external aesthetics; and the viscosity is too high after melting, which is inconvenient to apply

In the case of polyurethane hotmelts, prior art hotmelts are more prone to bubble formation due to the skin formed from the cured adhesive from the surface that is impermeable to carbon dioxide

In addition, the formed outer skin also blocks moisture and makes it difficult to penetrate deeper and enter the uncured adhesive layer. Therefore, it takes a long time for this type of hot melt adhesive in the prior art to achieve complete crosslinking. time or not at all, especially when applied in layer thicknesses of 1mm or more

[0004] At present, in the prior art, latent moisture curing agents, such as ketimines, aldimines, enamines, oxazolidines, etc., are added to polyurethane hot-melt adhesives to eliminate the generation of carbon dioxide bubbles. The crosslinking of latent moisture curing agents requires more water, so the rate of crosslinking is slower; and these latent moisture curing agents cause unpleasant odors to be released during the preparation and use of polyurethane hot melt adhesives. The environment and human body have caused great harm

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