1. Saturated polyester resin
Saturated polyester resin (oil-free alkyd resin) is mainly used in the production of coil coatings. Depending on the properties and structure of the resin, it can be used for the top coat, primer, back coat of coil coatings, and also for inks and thermal coatings. Saturated polyester resin for coils.
Characteristics of saturated polyester resin:
Saturated polyester resin requires good decorativeness, protection, durability, workability and processability of the coating film. The most used polyester topcoat is because the saturated polyester resin has the following characteristics:
(1) Strong versatility and good weather resistance. Mainly suitable for steel plate coating in the construction industry.
(2) The hardness and toughness are outstanding, and it has stick resistance, and the use grade is high.
(3) Economical. It is suitable for the general requirements of coil coating.
2.unsaturated polyester resin
The unsaturated polyester resin is generally a linear polymer compound having an ester bond and an unsaturated double bond formed by polycondensation of an unsaturated dibasic acid diol or a saturated dibasic acid unsaturated diol. Generally, the polyesterification polycondensation reaction is carried out at 190 ～ 220 ℃ until the expected acid value (or viscosity) is reached. After the polyesterization polycondensation reaction is completed, a certain amount of vinyl monomer is added while hot to make a thick The solution of such a polymer is called unsaturated polyester resin.
Characteristics of unsaturated polyester resin:
(1) Heat resistance. The thermal deformation temperature of most unsaturated polyester resins is between 50 and 60 ° C. Some resistance
Good thermal resin can reach 120 ℃.
(2) Mechanical properties. Unsaturated polyester resin has high tensile, bending, and compression strength.
(3) Chemical resistance. Unsaturated polyester resins have good resistance to water, dilute acids and alkalis, and poor resistance to organic solvents. At the same time, the chemical resistance of resins can vary greatly depending on their chemical structure and geometric switch.
(4) Dielectric performance. The dielectric properties of unsaturated polyacid resins are good.
(5) The unsaturated polyester resin changes from a soluble and fusible state to an insoluble and infusible state.
(6) It is still soluble in a suitable solvent and has good fluidity when heated.