The balance between low temperature and room temperature of hot melt pressure sensitive adhesive

Pressure-sensitive hot melt adhesives can show excellent adhesion properties at room temperature, such as peeling force, initial adhesion, etc., but the performance at low temperatures is not ideal. Mainly due to the sensitivity of pressure sensitive hot melt adhesives to ambient temperature. Generally speaking, most pressure-sensitive hot melt adhesives are designed for room temperature conditions of 25°C, but the market is unlikely to accept pressure-sensitive hot melt adhesives for use at specific temperature conditions from suppliers. Therefore, there is a need to provide thermal pressure sensitizers with a wide temperature range.

The most important issue in the design of pressure sensitive hot melt adhesives with such a wide temperature range is the glass transition temperature. Most general purpose pressure sensitive hot melt adhesives used at room temperature typically have a glass transition temperature of 0-10°C. Low temperature adhesion properties of pressure sensitive hot melt adhesives require lower glass transition temperature. However, the flow/wetting properties of this adhesive at room temperature will be reduced, which means that the performance of the pressure sensitive hot melt will be reduced. According to the above explanation, theoretically, no pressure-sensitive hot melt adhesive can guarantee excellent adhesive performance at both room temperature and low temperature.

However, when it comes to design skills, we can strike a balance in the following three areas.

First, we can choose an elastomer with an appropriate cross-sectional ratio to make the rubber phase composition as high as possible;

The second is to choose an elastomer with a broad molecular weight distribution.

Third, the adhesive is selected to form 2 glass transition temperature points.