How to achieve the dual personality of epoxy silicone oil - soft touch and chemical anchoring?
Introduction
Epoxy functional silicone grafting epoxy groups onto the side chains or ends of polydimethylsiloxane not only maintains the soft touch of silicone oil, but also provides the ability to react with polar substrates. It is a "cross-border star" in textile soft elastic finishing and electronic encapsulation.
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molecular design
Side chain type: epoxy equivalent 0.15-0.25 mol/100 g, suitable for fiber surface film formation, friction coefficient μ d 0.18;
Terminal type: epoxy equivalent 0.05-0.08 mol/100 g, combined with amine curing agent, can form a 3D cross-linked network, Tg -40 ℃, elongation at break 120%.
Textile applications
Immerse for 20 minutes at 50 ° C and pH 5.5, and the epoxy group reacts with the hydroxyl group of cotton fibers to open the ring. After 30 washes, the softness level remains at 4.
Electronic packaging
Epoxy silicone oil/epoxy diluent=1/1, combined with modified amine curing agent. After curing at 150 ° C/1 h, the volume resistivity is 10 ¹⁵Ω· cm, and the temperature is cycled 1000 times at -40~125 ° C.
Formula trap
Water content>500 ppm will catalyze epoxy self polymerization and cause viscosity to soar;
Excessive amine value leads to uncontrolled reaction rate, which needs to be balanced with acid anhydride or latent curing agent.
conclusion
The greatest charm of epoxy silicone oil lies in its "cool and cute": a gentle touch can bring a silky feel, which can become the patron saint of electronic devices. Making good use of epoxy equivalent and curing system is the key to mastering its dual personality.