Effect of pressure sensitive adhesive properties

I. Influence of major components

The properties of pressure-sensitive adhesives vary from composition to composition. Rubber-based pressure-sensitive adhesives are mainly based on natural rubber. Due to the high molecular weight, low glass transition temperature, and good compatibility with tackifying resins, the resulting pressure Sensitive glue has good adhesion, low temperature performance, fast viscosity and adhesion are better, the main drawback is poor aging resistance. Acrylic pressure-sensitive adhesives are mainly copolymerized with acrylate monomers, and have good transparency, cohesive strength and adhesive properties, especially good adhesiveness to the surface and the porous surface of polar adherends. Excellent aging resistance.

The main components of thermoplastic elastomer pressure sensitive adhesives are styrene elastomers SIS and SBS. The solvent pressure sensitive adhesives prepared have high viscosity, high cohesive strength and high peel strength. Due to the presence of double bonds in the molecular structure, it is not resistant to aging, but the aging resistance after oxidation is greatly improved.

Silicone pressure-sensitive adhesive is mainly composed of silicone rubber and silicone resin, and its resistance to high and low temperature is very good. It has good adhesion to polyolefin and fluoropolymer.

Second, the influence of the relative molecular mass and its distribution

The relative molecular mass and its distribution have a great influence on various properties of the pressure-sensitive adhesive. When the relative molecular mass of the pressure-sensitive adhesive is reduced, the bulk viscosity can be reduced, which is beneficial to the wetness of the adherend surface, thereby improving the interface adhesion. Together force. However, when the molecular weight is too low, the cohesive strength is poor, and the adhesive layer is susceptible to cohesive failure during peeling. Increasing the relative molecular mass can increase the cohesion, but excessive relative molecular mass can hinder dispersion and wetting. Therefore, the relative molecular mass of the pressure sensitive adhesive must be within a certain range in order to obtain good adhesive properties. The relative molecular mass distribution also has a greater impact, generally a wider relative molecular mass distribution of the pressure-sensitive adhesive has better adhesive properties.

Third, the glass temperature effect

The glass transition temperature Tg has a great influence on the properties of pressure sensitive adhesives. The pressure sensitive adhesives with different Tg have higher bulk modulus and coexistence elastic modulus at room temperature, lower peel strength, loss of pressure sensitivity, low Tg, and cohesive strength. Low, will cause peeling damage, therefore, the pressure-sensitive adhesive Tg must be maintained within a certain temperature range is generally -20 ~ 600C.