First, saturated polyester resin
Saturated polyester resin (oil-free alkyd resin) is mainly used for the production of coil coatings, respectively, depending on the resin properties and structure can be used for coil coating topcoat, primer, back paint, but also for ink and heat coating Saturated polyester resin for rolls.
Features of saturated polyester resin:
Saturated polyester resin requires coating film has good decorative, protective, durability, workability and processability, the use of up to polyester topcoat, because the saturated polyester resin has the following characteristics:
(1) High universality and good weatherability, mainly applicable to the steel plate coating in the construction industry.
(2) is the hardness and toughness are outstanding, and has stain resistance, the use of high grade.
(3) economy.Applicable to the general requirements of the coil coating.
Second, unsaturated polyester resin
Unsaturated polyester resins are generally linear polymer compounds having ester bonds and unsaturated double bonds formed by the polycondensation of an unsaturated dibasic acid diol or a saturated dibasic acid unsaturated diol. The polycondensation reaction is carried out at 190-220 ° C until the desired acid value (or viscosity) is reached. After the polycondensation reaction is complete, a certain amount of vinyl monomer is added while hot to form a viscous liquid The polymer solution is called unsaturated polyester resin.
Unsaturated polyester resin features:
(1) heat resistance Most of the unsaturated polyester resin heat distortion temperature is 50 ~ 60 ℃, some good heat resistance of the resin up to 120 ℃.
(2) Mechanical properties: Unsaturated polyester resin has high tensile strength, bending strength and compression strength.
(3) Chemical resistance Unsaturated polyester resin is better in water resistance, dilute acid and dilute alkali, poor in organic solvent resistance. Meanwhile, the chemical resistance of resin varies with its chemical structure and geometrical switch, There can be a big difference.
(4) Dielectric properties Unsaturated polyacid resins have good dielectric properties.
(5) unsaturated resin from soluble, meltable state into insoluble, non-melting state.
(6) is still soluble in a suitable solvent and has good fluidity when heated.