Basic knowledge of hot melt glue
Hot melt adhesive, or hot glue, is a plastic adhesive. Its physical state changes with the temperature change. However, its chemical properties remain unchanged. It is non-toxic and tasteless. And it is an environmentally friendly chemical product. As it is solid, it is easy to package, transport and store. It is solvent-free, pollution-free, and non-toxic. It has advantages of simple production process, high added value, high bonding strength, and fast speed.
Existing varieties are modified by blending, grafting and other methods to improve the performance of hot melt adhesives. For example, stabilizers are used to prevent oxidation; tackifiers to improve bonding strength; paraffin to reduce viscosity and change surface properties. Various fillers can improve viscosity, melting point and bonding strength. It is of great value to research the variety and dosage of various compounding agents, and optimize the formula to meet different needs.
Hot melt adhesive basic resin
The basic resin of hot melt adhesive is ethylene and vinyl acetate copolymerized under high temperature and high pressure, namely EVA resin. This resin is the main component for making hot melt adhesive. The proportion and quality of the basic resin determine the basic properties of the hot melt adhesive. Melt index (MI) 6-800, low VA content. The higher the crystallinity, the higher the hardness. Under the same circumstances, the greater the VA content, the lower the crystallinity, the more elastic. High strength and high melting temperature are also poor in wetting and permeability of adherends. On the contrary, if the melting index is too large, the melting temperature of the glue is low, the fluidity is good, but the bonding strength will be reduced. The choice of its auxiliary agent should choose the appropriate ratio of ethylene and vinyl acetate.
Development of new hotmelt adhesives
Curable and functional hot melt adhesives are the two major categories of new products on the market. The main feature of the former is to improve the high temperature resistance and increase the softening point to above 120°C, thereby expanding its scope of use.
Functional hot melt adhesives are designed for specific occasions and can achieve specific functions, such as water-soluble or dispersible hot-melt adhesives, hot-melt sealants, hot-melt pressure-sensitive adhesives, etc.
Below are instructions for hot melt sealants. It is a one-component, solvent-free, non-fogging, non-vulcanizing, permanent plastic insulating glass first sealant based on polyisobutylene rubber. Hot melt butyl sealant maintains its plasticity and sealing properties over a wide temperature range without cracking and hardening of the surface. It has good adhesion to glass, aluminum alloy, galvanized steel, stainless steel and other materials. Due to its extremely low water vapour transmission rate, it forms an excellent moisture-resistant system with elastomeric sealants. Features: good sealing effect, easy quality assurance, no curing period, saving floor space. It also has features of environmentally friendly, no waste in use, clean environment, saving time, raw materials, staff, and reducing production costs.
In addition to the more general EVA and TPR hot melt adhesives, enterprises should also focus on the research and development of some high-tech hot melt adhesive products. They have been widely used in the West and have great application potential, including: reactive hot melt adhesives, water dispersion hot melt adhesives adhesive, high-grade PA hot-melt lining pellets and high-strength hot-melt pressure-sensitive adhesive, etc.
GC Adhesives Company have been devoted to manufacture hot melt adhesive and develop new products for years. As the vast applications of hot melt adhesives, we are quite pleased to start cooperation with your business for a wide market.