Medical hot melt adhesive is a common adhesive in the medical field, which is mainly used in wound dressing, medical catheter fixation, transdermal patch and other scenes, and needs to meet the requirements of safety (non-toxic, non-irritating), biocompatibility and specific bonding properties (such as sweat resistance, water resistance and gentle peeling). The following are its main types and characteristics: 

1. Types of medical hot melt adhesive Medical hot melt adhesive is a kind of adhesive that is coated after heating and melting, and cured and bonded after cooling, with the characteristics of rapid curing, environmental protection and solvent-free. Common types include: 1. Acrylate hot melt adhesive ingredients: acrylate polymer as the base material, adding tackifying resin, antioxidant and other additives. Features: high adhesive strength, good water resistance and sweat resistance, suitable for long-term fixed dressing. Good transparency, low irritation to skin, and can be used for sensitive parts. The melting temperature is low (usually 80-120℃), which is convenient for processing and coating. Application: wound patch, indwelling needle fixing patch, pocket-making chassis, etc.

2. Composition of silicone rubber hot melt adhesive: silicone rubber (polydimethylsiloxane) is the main body, and cross-linking agent and filler are added. Features: excellent biocompatibility, no sensitization, suitable for sensitive skin and long-term contact with wounds. It is soft and elastic, conforms to the skin curve, and has light pain when peeling (close to the characteristics of low-pain glue). High temperature and low temperature resistance, strong chemical stability. Application: High-end medical dressing, catheter fixing device, wearable medical device sensor patch. 3. Polyurethane hot melt adhesive component: It is made of polyurethane prepolymer and contains polar groups (such as-NCO). Features: excellent flexibility and tensile resistance, suitable for bonding in sports parts or joints. Good solvent resistance, resistant to corrosion by disinfectant (such as alcohol). Different hardness (from soft rubber to hard rubber) can be achieved by adjusting the formula. Application: sports wound dressing, elastic bandage, transdermal drug delivery patch. 4. Ethylene-vinyl acetate copolymer (EVA) hot melt adhesive composition: ethylene-vinyl acetate copolymer is mixed with tackifier (such as rosin ester) and wax. Features: low cost, good melt fluidity, suitable for large-area coating. The initial viscosity is high, but the long-term water resistance is slightly weak, so it needs to be used with breathable substrate. Application: disposable medical adhesive tape, common wound dressing primer.