Time:2021-08-17 Preview:216
Bakelite powder, also known as bakelite powder, has good insulating properties, used in the manufacture of electrical appliances and daily industrial products. It is mainly made of phenolic plastic with wood powder as filler.
When formaldehyde/phenol (molar ratio) is less than 1, thermoplastic products can be obtained, called thermoplastic phenolic resin, namely linear phenolic resin, it does not contain further condensation group, curing agent and heating to cure. Such as hexamethyl enetetramine as curing agent, curing temperature 150℃, mixed with fillers made of molding powder commonly known as bakelite powder. When the formaldehyde/phenol (mole ratio) is greater than 1, to get a first stage under alkali catalytic resin, namely type thermosetting phenolic resin, soluble in organic solvent, a phase containing resin can further hydroxymethyl condensation, so there is no need to add curing agent which can cure: the reaction heated by resin b stage, also known as half soluble phenolic resin, insoluble melt but not to swelling and softening. Further reaction will be insoluble inmelting body structure stage c resin, also known as insoluble phenolic resin. Phase A resin can also cure itself after long-term storage.
The curing form of thermosetting phenolic resin is divided into two kinds: room temperature curing and heat curing. Curing at room temperature can use non-toxic room temperature curing agent NL, benzene sulfonyl chloride or petroleum sulfonic acid can also be used, but the toxicity and irritation of the latter two materials are larger.