- Mar 22, 2018 -
What is Polyresin？
First, what is polyester resin. Polyester Resin Generic term for macromolecules obtained by the polycondensation of dihydric or dibasic acids or polyhydric alcohols and polybasic acids.
Polyester resins are divided into saturated polyester resins and unsaturated polyester resins.
The difference between the polyester resin and the alkyd resin is that the raw material of the synthetic polyester resin does not contain the vegetable oil or fatty acids that are the main constituents of the oil. Polyesters can be divided into saturated polyesters and unsaturated polyesters. Saturated polyester means that the synthetic raw material does not contain unsaturated bonds other than benzene rings.
Second, the use of polyester resin
Polyester resin used for adhesive glass steel, hard plastic, concrete, electrical cans and other seals.
Third, polyester resin classification Unsaturated polyester resin. Different types of polyhydric acids and polyols can be used to synthesize different types of saturated polyester resins. If linear and dibasic acids are used, a polyester resin containing only a linear structure is produced. If a polybasic acid is used, it contains a benzene ring (e.g., phthalic anhydride, terephthalic acid, trimellitic anhydride, etc.) What is produced is a polyester resin containing a benzene ring structure. If a chemical reaction is used to introduce other components than polyols and polybasic acids, a modified polyester resin is produced.
Synthetic Polyester Resin If linear polyols and polybasic acids are used, the resulting resin has a linear structure and is very flexible. Its main use is not in the coating industry. Nylon that comes into contact with daily life and work is typical. The linear polyester, the most typical linear polyester nylon-66, is the product of hexamethylene diamine and 1,6-adipic acid, and can also be synthesized from 1,6-hexanediol and 1,6-hexanedioic acid in terms of structure. .
If a synthetic polyester resin is reacted with a benzene ring polybasic acid and a polyhydric alcohol, a resin containing a benzene ring structure is synthesized. The rigidity of the benzene ring gives the resin a hardness, and the stable structure of the benzene ring gives the resin a chemical resistance.
The unsaturated polyester resin most commonly used in the paint industry is a polyester resin containing hydroxyl functional groups, which is cured by cross-linking with isocyanate, amino resin and other resins. Different raw materials make different contributions to the properties of the resin. When selecting raw materials, the performance requirements of the resin must be considered. The raw materials that can help the required properties of the resin should be selected to provide various functionalities, hardness, and softness. consider.
Saturated polyester resin
Saturated polyester resin (oil-free alkyd resin) is mainly used to produce coil coatings. It can be used for top coats, primers and back coats of coil coatings, depending on the properties and structure of the resin. It can also be used for inks and thermal overlays. Saturated polyester resin for coils.
312C oil-free alkyd resin is a high-molecular-weight linear saturated polyester resin developed by our factory. It is mainly used for hot-laminated film adhesives and coil coating primers. It has excellent adhesive properties and good Hardness and toughness balance performance.
Epoxy primer is characterized by good adhesion to the substrate and good compatibility with the finish. At the same time, the epoxy primer has outstanding corrosion resistance and strong chemical resistance.
The characteristics of polyester primers are good adhesion, versatility, outstanding weatherability and flexibility.
The backside paint is applied to the back side of the coil to provide protection and provide appearance and durability. The back side is painted with amino polyester type.
Variety of saturated polyester topcoats
Coil topcoats are the last coating on the surface of the coil and require a higher level of finish. It requires the coating to have good decorative, protective, durable, workability and processability. At present, the most used is the polyester topcoat. At present, the resin that our factory is suitable for coil coating is mainly the following: Varieties:
(1) 335 saturated polyester: It is characterized by strong versatility and good weather resistance. It is mainly used for steel coating in the construction industry.
(2) 345 Saturated Polyester: It is characterized by its outstanding hardness and toughness, and its resistance to smearing. Applicable to OT requirements of the home appliance industry and aluminum plastic composite coating.
(3) 301B, 385 saturated polyester: Its characteristics are economical. Suitable for coil coating of general requirements. 385 resin miscible, can be compatible with 582-2 amino resin.