There are many types of adhesives, which can be divided into many types according to their ingredients and uses. Here, the classification and use of adhesives are sorted out from these two aspects.
Classified by ingredients
There are many types of adhesives. The more common ones are: urea-formaldehyde resin adhesives, polyvinyl acetate adhesives, polyacrylic resin adhesives, polyacrylic resins, polyurethane adhesives, hot melt adhesives, epoxy resin adhesives, synthetic adhesives, and so on.
1. Organic silicone adhesive
It is a kind of sealing adhesive, which has the characteristics of cold resistance, heat resistance, aging resistance, waterproof, moisture resistance, high expansion fatigue strength, small permanent deformation, and non-toxic. In recent years, such adhesives have developed rapidly in China, but at present, the raw materials of organic silicone adhesives in my country are partly imported.
2. Polyurethane adhesive
It can bond a variety of materials. After bonding, it can still maintain the physical and chemical properties of the material at low or ultra-low temperature. It is mainly used in shoemaking, packaging, automobiles, magnetic recording materials and other fields.
3. Polyacrylic resin
Mainly used in the production of pressure-sensitive adhesives, but also in the textile and construction fields.
Adhesives for construction: mainly used for decoration, sealing or bonding between structures in construction projects.
According to different raw materials, it can be divided into EVA hot melt adhesive, polyamide hot melt adhesive, polyester hot melt adhesive, polyolefin hot melt adhesive, etc. At present, EVA hot melt adhesive is mainly produced and used. The main raw materials of polyolefin series adhesives are ethylene series, SBS and SIS copolymers.
5. Epoxy resin adhesive
Can bond metal and most non-metal materials, widely used in construction, automobiles, electronics, electrical appliances and daily household products
Mainly used in the wood processing industry, the formaldehyde emission after use is higher than the international standard.
Adhesives for wood processing: used for medium density fiberboard, gypsum board, plywood and particle board, etc.
7. Synthetic adhesive
Mainly used in wood processing, construction, decoration, automobile, shoemaking, packaging, textile, electronics, printing and binding, etc. Varieties include hot melt adhesives, silicone sealant adhesives, polyacrylic acid adhesives, polyurethane adhesives, and PVC plastic adhesives for automobiles.
Classified by purpose
1. Sealing adhesive
It is mainly used for the connection of doors, windows and prefabricated houses. The high-end sealing adhesives are silicone and polyurethane adhesives, and the mid-range ones are neoprene-based adhesives and polyacrylic acid. In my country, in the construction adhesive market, organic silicone adhesives and polyurethane sealant adhesives should be the future development direction. At present, they account for about 30% of the sales of construction sealant adhesives.
2. Adhesive for building structure
Mainly used for the connection between structural units. Such as external repair of reinforced concrete structures, metal reinforcement and fixing, and construction on-site construction, generally consider the use of epoxy resin series adhesives.
3. Adhesives for automobiles
There are four types of adhesives, namely, car body, car interior decoration, windshield and car body chassis adhesives. Among them, the most used are polyvinyl chloride plastic adhesives, neoprene adhesives and asphalt series adhesives.
4. Adhesive for packaging
It is mainly used to make pressure-sensitive tapes and pressure-sensitive labels, and to bond the surfaces of packaging materials such as paper, plastic, and metal. The adhesive for paper packaging materials is polyvinyl acetate emulsion. Adhesives for plastic and metal packaging materials are polyacrylic emulsion, VAE emulsion, polyurethane adhesive and cyanoacrylate adhesive.
5. Adhesives for electronics
The consumption is small, and most of them are used in integrated circuits and electronic products. Currently, epoxy resin, unsaturated polyester resin, and organic silicone adhesive are mainly used.
6. Adhesives for shoemaking
The annual consumption is about 125,000 tons, of which 110,000 tons are needed for neoprene adhesives and about 15,000 tons for polyurethane adhesives. Since neoprene adhesives require benzene as a solvent, and benzene is harmful to the human body, the development should be restricted. To meet the development needs of the shoe industry, the use of polyurethane adhesives will be the direction.