Low Specific-Gravity Body Sealer Containing Resin Balloons

A lightweight body sealer that cures at low temperatures was developed. In order to make the sealer lightweight, it is necessary to add light raw materials. In this development, the technique in which the weight reduction effect adds the resin balloon which is high and is easy to fluctuate the thickness and the particle diameter of shell was selected. Two types of resin balloons were used in combination with each other. High pressure-resistant resin balloons made of polyacrylonitrile (PAN) were one type, of which pressure resistance was increased by optimally designing heat-expandable microspheres (raw material), and the other type was high pressure-resistant polyester (PES) balloons. To enable the sealer to cure at low temperatures, it is necessary to use a resin that cures in the specified temperature zone and has the necessary physical properties. To this end, two types of resins, acrylic and polyurethane, were selected as base resin due to their good mechanical properties, when curing at low temperatures, and their versatility. These materials were used to develop a new sealer that can contribute to the reduction of vehicle body weight.