What are the types of hot melt adhesives and what are the characteristics?
Published on Nov. 27, 2019
First, classification by chemical composition and characteristics:
1. Polyolefin hot melt adhesive: (1) Polyethylene hot melt adhesive: good bonding performance, low price, easy adhesion to porous surface, etc.; (2) Polypropylene hot melt adhesive: certain adhesiveness, curing The speed is slightly slower and the heat resistance is not high, and it is often mixed with low molecular polyethylene or crystalline polypropylene to improve the curing speed and temperature resistance.
2. Ethylene and its copolymer hot melt adhesives: (1) comonomer: propylene, vinyl acetate, acrylic acid, maleic anhydride, vinyl chloride, etc.; can be more than two; (2) ethylene-vinyl acetate Copolymer (EVA) hot melt adhesive: excellent adhesion, softness, heating fluidity and cold resistance; excellent chemical resistance, thermal stability, weather resistance and electrical properties; low strength, heat resistance, Not resistant to fatty oils, etc.
3. Polyester hot melt adhesive: excellent electrical insulation; good bonding strength; impact resistance, water resistance, heat resistance, cold resistance, medium resistance and elasticity are good; can bond a variety of materials; melt viscosity high.
4. Polyamide hot melt adhesive: excellent heat resistance, cold resistance, electrical properties, oil resistance, chemical resistance and medium resistance; odorless, colorless; fast curing; can bond a variety of metals and non-metals; Other resins have good compatibility. (1) High molecular weight polyamide hot melt adhesive: good fluidity, high bonding strength, dry cleaning, water washing; (2) low molecular weight polyamide hot melt adhesive: good strength and toughness, Most of the performance is better than EVA hot melt adhesive.
5. Polyurethane hot melt adhesive: (1) Thermoplastic polyurethane hot melt adhesive: better strength than polyester, polyolefin hot melt adhesive, good elasticity, excellent mechanical properties, simple operation, suitable for high speed bonding automatic line production, no pollution, commonly used For bonding fabrics, metals, glass, etc.; (2) reactive polyurethane hot melt adhesive: the advantages of hot melt adhesive, reactive adhesive and polyurethane adhesive, no pollution, high efficiency.
6. Styrene and its block copolymer hot melt adhesives: fluidity and plasticity at high temperature; flexibility and resilience at room temperature (1) SBS: good solubility, good compatibility, resin addition and viscosity addition The agent can reduce its melt viscosity, and is very suitable for preparing hot melt adhesive and hot melt pressure sensitive adhesive; (2) SIS: both plastic solubility, thermoplasticity and vulcanized rubber toughness, elasticity, low modulus, low solution viscosity and melt viscosity , good processing performance, good cohesion, excellent adhesion, making the main material of hot melt pressure sensitive adhesive.
7. Other types of hot melt adhesives.
Hot Melt Packaging Adhesive
8. New hot melt adhesive: (1) Reactive hot melt adhesive: heat resistance, heat creep resistance, cold resistance, chemical resistance and adhesion to metal, wood, glass, leather, plastic, etc. Prolonged set time, meet the needs of some assembly work, and have a wider application range; (2) Hot melt pressure sensitive adhesive: no solvent, no pollution, easy to use; disadvantages are insufficient heat resistance and cohesion → development of new thermoplastic elastomer (3) Solvent-based hot melt adhesives: Many companies need to use hot melt adhesives, but they cannot use existing granular or powdery products. They can only be coated in a liquid state. After the solvent is dried, it can be used in the base. The thin and uniform hot melt adhesive film is bonded under hot pressure; (4) Water-soluble and water-dispersible hot melt adhesive: The disadvantage of EVA hot melt adhesive: mainly used in bookbinding, packaging paper and other cellulosic materials. When the old paper is recycled, there are problems such as insolubilization, and it is easy to adhere to the spots on the recycled paper, which affects the appearance and printability, and the bonding portion needs to be cut off before the recycling treatment, which is time consuming and laborious; (5) Rewet type hot melt adhesive: Coating the adhesive with hot melt technology On one side, the other side is a hot melt adhesive that wets the two sides after bonding with water; (6) Other new hot melt adhesives: water sensitive hot melt adhesive, high temperature resistance hot melt adhesive, heat Melt seal adhesive, flame retardant hot melt adhesive, foam hot melt adhesive, biodegradable hot melt adhesive.