Warm Global Customers
With China Plastic Machinery
With China Plastic Machinery
Thermosetting refers to the property that it cannot soften and be repeatedly molded when heated, nor can it be dissolved in solvents. Bulk polymers have this property.
Thermosetting refers to the property that it cannot soften and be repeatedly molded when heated, nor can it be dissolved in solvents. Bulk polymers have this property.
It can soften and flow when heated for the first time. When heated to a certain temperature, a chemical reaction occurs, cross-linking and curing occurs, and it becomes hard. This change is irreversible. After that, it can no longer soften and flow when heated again. It is precisely with the help of this characteristic that molding is carried out. The plasticizing flow during the first heating is used to fill the mold cavity under pressure, and then solidify into a product of a certain shape and size. This material is called thermosetting plastic.
The resin of thermosetting plastics is linear or branched before curing. After curing, chemical bonds are formed between the molecular chains to form a three-dimensional network structure. It can no longer melt and touch, and it cannot be dissolved in solvents.
Plastics mainly used for heat insulation, wear resistance, insulation, high voltage resistance and other harsh environments are mostly thermosetting plastics. The most commonly used ones should be frying pan handles and high and low voltage electrical appliances.
Common thermosetting plastics include phenolic resin, urea-formaldehyde resin, melamine resin, unsaturated polyester resin, epoxy resin, silicone resin, polyurethane, etc.
When thermosetting materials are exposed to fire, they will carbonize, not melt, and will not produce droplets. Depending on the depth of the carbonization layer of different materials, some materials will smolder. Example: When polyurethane is exposed to fire, a carbonized layer will form on the surface to prevent the flame from penetrating. Phenolic resin will carbonize when exposed to fire and continue to be flame retardant.
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