Hot Glue is a kind of adhesive with plasticity. Its physical state can change with temperature within a certain temperature range, while its chemical properties remain unchanged. Hot glue is non-toxic and odorless. It is an environment-friend chemical product. Because Hot Glue is solid, it is easy to pack, transport and store. Hot Glue is popular because of their simple production process, high added value, high bonding strength and fast operation.
The basic resin of Hot Glue is EVA resin. It is formed by copolymerization of ethylene and vinyl acetate at high temperature and pressure. EVA resin is the main component of Hot Glue. The proportion and quality of the basic resin determine the basic properties of the Hot Glue.
Viscosifier is one of the main additives of EVA Hot Glue. At a certain temperature, the basic resin melts and has adhesive power.. But when the temperature drops, it is difficult to wet and permeate the paper, lose the bonding ability, unable to achieve the bonding effect. The fluidity of the colloid and the wettability of the adhesive can be improved by adding the viscosifier. Improve bonding properties. To achieve the desired bond strength. General viscosifiers are rosin, modified rosin (138 or 145), C5 petroleum resin, C9 petroleum resin, terpene resin and so on.
Viscosity adjuster is also one of the main additives of Hot Glue. Its role is to increase the fluidity of the gel, adjust the solidification speed, in order to achieve the purpose of fast bonding firm. Otherwise, the viscosity of Hot Glue is too high, unable or not easy to flow. Add softening point of low viscosity adjuster, you can achieve good penetration when bonding, sticky firm purpose. Generally choose paraffin wax, microcrystalline wax. Synthetic wax (PE or PP), Foto wax, etc.
Adding the right amount of antioxidant is to prevent EVA hot melt adhesive from aging too early. Because colloid in melting, high temperature will lead to oxidation decomposition. The addition of antioxidant can ensure that the bond property does not change at high temperature.
How to choose Hot Glue?
1. The color difference of hot melt adhesive.
If there is no special requirement for color, yellow hHot Glue is recommended. Generally speaking, yellow Hot Glue has better adhesion than white.
2. The surface treatment of the adhered material.
The surface treatment of Hot Glue is not as strict as other adhesives. However, the dust and oil on the surface of the adhered material should be properly treated in order to make the Hot Glue work better.
3. The operation time.
Fast operation is a major feature of Hot Glue. The operation time of Hot Glue is generally about 15 seconds. With the wide application of modern assembly line production, the operation time of Hot Glue is shorter and shorter. Such as book binding and sound box manufacturing of Hot Glue operation time requirements to reach about 5 seconds.
4. Temperature resistance.
Hot Glue is sensitive to temperature. Above a certain temperature, the Hot Glue begins to soften. Below a certain temperature, Hot Glue will become fragile. Therefore, the choice of Hot Glue must fully take into account the temperature changes of the environment where the product is located.
The viscosity of hot melt adhesive is divided into early viscosity and late viscosity. Only when the early viscosity and the late viscosity are consistent, the hot melt adhesive can be stable with the adhesive. In the production process of hot melt adhesive, it should be guaranteed to have oxygen resistance, halogen resistance, acid and alkali resistance and plasticity. The adhesive material is different, hot melt adhesive played by the viscosity is also different. Therefore, different hot melt adhesives should be selected according to different materials.
How to grasp the future market application of hot melt adhesives? Hot melt adhesive manufacturers should see more business opportunities.
From the market research, the manufacturing and processing industries as well as other commercial sectors are planning to expand the application and usage of hot melt adhesives as the formulations of hot melt adhesives continue to be upgraded. The Chinese market will undoubtedly be the major growth market for hot melt adhesives in the coming period.
With the rising demand for environmentally friendly hot melt adhesive products in China, new green products are expected to become the new favorite in the Chinese adhesive market.