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What is the difference between saturated polyester and unsaturated polyester?

Jan 30, 2019

The difference between saturated polyester and unsaturated polyester.

Saturated polyester resin:

Saturated polyester resins with different types and properties can be synthesized by using different polyacid and polyol.If use are straight chain structure of glycol and dibasic acid is produced only with linear structure of polyester resin, if use of polybasic acid containing benzene ring (example: phthalic anhydride, terephthalic acid, trimellitic anhydride, etc.) is the polyester resin containing benzene ring structure, if the chemical reaction is introduced into other ingredients except polyols, polybasic acid, is produced by the modified polyester resin.

Synthetic polyester resin if the use of linear structure of polyol and polyacid, synthetic resin has a linear structure, flexibility is very good, the main purpose is not in the paint industry;Nylon in daily life and work is a typical linear polyester, the most typical linear polyester nylon -66 is the product of hexamethylene diamine and 1, 6-adipic acid, from the structural point of view can also be used to synthesize 1, 6-hexanediol and 1, 6-adipic acid. 

If the polyester resin is synthesized by the reaction of polyacid and polyol of benzene ring, the resin containing benzene ring structure can be synthesized. The rigidity characteristic of benzene ring endows the resin with hardness, while the stable structure characteristic of benzene ring endows the resin with chemical resistance.

Unsaturated polyester resin:

It is a linear polymer compound with ester bond and unsaturated double bond generally formed by polycondensation of unsaturated dihydric acid dihydric alcohol or saturated dihydric acid dihydric alcohol.Usually, polyester melt polycondensation reaction was conducted in 190 ~ 220 ℃, until the desired acid value (or viscosity), at the end of the polyester melt condensation reaction, add a certain amount of vinyl monomer, match into sticky liquid, the polymer solution is called unsaturated polyester resin.

It is often used for thickening and curing the surface of objects. When used, it is just like painting, adding layers upon layers and releasing styrene and other harmful gases in the curing process. 

Unsaturated polyester resin is one of the most commonly used thermosetting resins. It is a linear polymer formed by condensation polymerization of saturated dibasic acid, unsaturated dibasic acid and dibasic alcohol. The resin solution with a certain viscosity is diluted by crosslinking monomer or active solvent, which is referred to as UP for short.

Unsaturated polyester resins are toxic, mainly because of the toxicity of styrene.


QuanZhou Neweco High Polymer Material Co.,Ltd.

Neweco is one of the leading unsaturated polyester resin manufacturers and  suppliers,widely used in automobiles, ships, rail transit, wind power  generation, pipe cans, heat and corrosion protection, building  materials, stone repair, sanitary ware, artificial stone and other  industries. Suitable for hand lay-up, spray, pultrusion, winding,  molding, vacuum introduction / RTM, casting and other molding processes. Neweco Resin is committed to excellence and focuses on the application  of composite materials to provide customers with comprehensive  solutions.


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