resin modified silicone resin as the base material of the adhesive
Pure silicone resin can not be used as structural adhesive because of its low mechanical strength, but when it is copolymerized with organic resin such as polyester, epoxy or phenolic, the adhesive made by the excellent thermal stability of silicone and organic resin excellent mechanical properties and adhesive relay melt in one, so it has been widely used.
(1) Epoxy modified silicone adhesive
Epoxy modified silicone resin adhesive, it is cured at 200℃ for 2 hours, can be bonded steel, duralumin and silicone plastics, can be used between 200-250℃, can also be used in 300℃ for a short time.
Another epoxy-modified silicone adhesive is water resistant and can be used for bonding steel, aluminum, glass fiber laminates, ceramics and titanium alloys, all of which can be used at 300℃. After thermal aging at 300℃ for 50h, the bonding strength of the bonded titanium alloy still maintains 33% of the initial strength at room temperature and 83% of the initial strength at 300℃.
There are also adhesives for welding and riveting, consisting of liquid epoxy resin, silicone curing agent and zinc powder, which can be cured at 100-110℃ and used between -60-150℃. The ratio of epoxy resin to silicone resin is 1:9, if the epoxy resin is too little, the room temperature strength is low; On the other hand, too much epoxy resin, it is easy to brittle. This adhesive in use, with appropriate sebacic acid and oxalic acid as curing agent, can be used for bonding metal and non-metal.
The epoxy modified silicone resin with polyamide or maleic anhydride as curing agent has also been reported to have high bonding strength. The shear strength of the epoxy modified silicone resin with polyamide or maleic anhydride as curing agent is 8.14MPa and 10.3MPa, respectively, after aging at 200℃ for 40h. It is found that the shear strength increases with the increase of epoxy resin content, but the heat resistance decreases.