Biomedical adhesives are classified into two types. One is used for hard organization systems, which isapplied to bonding systems for artificial joints and to dental fields. Adhesives of this type are made of acrylicresins mixed with powdered resins and liquid polymers. The other is used for soft organization systems, whichis applied to blood vessels and nerves, etc. Adhesives of this type are made of cyanoacrylate resins, instantquick–drying glues, which are recently used for micro surgeries. Creature-originated fibrin resin systems madefrom blood are also used as medical adhesives.

Effect of molecular weight and the molecular weight distribution（ polydispersity index；PDI） of butylacrylate - acrylic acid copolymer as main component of pressure sensitive adhesives（ PSAs） on the gelformation and the mechanical properties were studied. The copolymer was lightly crosslinked and the extentwas varied. The PDI showed considerable effect on both the initiation of gel formation using low concentrationof the crosslinking agent（ 4-functional epoxy） and the apparent saturation of the gel fraction with increasingthe crosslinking agent. Also, the PDI contributed greatly to the change of creep compliance（ time dependencyof deformation）. In general, creep compliance relates to flow or deformation of PSAs after pasting, whichaffects to the adhesive strength and tack with changing contact time. Therefore, creep compliance and theretardation spectra would be the powerful tools to analyze mechanical and adhesive properties of PSAs.

Fluoropolymers have several excellent properties, but their low adhesion properties are only onedisadvantage. Surface modification of fluoropolymers is essential for adhesion between fluoropolymers andother types of materials. Although conventional plasma treatment is not enough to adhere fluoropolymers toother types of materials, we found out that heating during plasma treatment has extremely positive effect onimprovement in adhesion property of fluoropolymers. At the time, we controlled the surface temperature offluoropolymers via the applied power density for plasma generation. Considering about expansion of plasmaarea for high throughput, the cost of remodeling becomes much higher with increasing the size of a plasmatreatment equipment. Therefore, we considered to use a heater for controlling the surface temperature duringplasma treatment. We successfully demonstrated that heat-assisted plasma treatment using a heater alsodrastically improved the adhesion property of fluoropolymers. The key points for strong adhesion were notonly generation of oxygen-containing functional groups but also surface hardening.