Unsaturated polyester resin on the human body?
Unsaturated polyester is a linear polymer compound with ester bonds and unsaturated double bonds, formed by condensation of polyols with unsaturated dicarboxylic acids (or anhydrides) or a mixture of them with saturated dicarboxylic acids (or anhydrides).Usually, polyester melt polycondensation reaction was conducted in 190 ~ 220 ℃, until the desired acid value (or viscosity).At the end of the polyester shrinkage reaction, when it is hot to add a certain amount of vinyl monomer, with a thick liquid, such a polymer solution called unsaturated polyester resin.
Physical and chemical properties of various polyester resins
1, physical properties of the relative density of unsaturated polyester resin in the 1.11 ~ 1.20, curing the volume shrinkage rate is large, some physical properties of curing resin are as follows:The vast majority of the thermal deformation temperature of the unsaturated polyester resin in 50 ~ 60 ℃, some good resin heat resistance up to 120 ℃.Red heat expansion coefficient alpha 1 (130 ~ 150) x 10-6 ℃.The mechanical properties.Unsaturated polyester resin has high tensile, bending and compression strength.Chemical corrosion resistance is self.Unsaturated polyester resin water, dilute acid, dilute alkali performance is better, the performance of the poor resistance to organic solvents, at the same time, the resin chemical corrosion resistance with its chemical structure and the different geometric switch, can have great differences.Of dielectric properties.The dielectric properties of unsaturated polyacid resin are good.
2. Chemically unsaturated polyester is a linear macromolecular compound with multifunctional groups. It has polyester chain bonds and unsaturated double bonds on its backbone chain, and carboxyl and hydroxyl groups on both ends of macromolecular chain.The double bond on the main chain can copolymerize and cross-link with the vinyl monomer, so that the unsaturated polyester resin changes from soluble and fusible state to insoluble and fusible state.Ester bonds on the main chain can undergo hydrolysis reactions, which can be accelerated by acids or bases.If copolymerized with styrene, the hydrolysis reaction can be greatly reduced.In acidic media, hydrolysis is reversible, not complete, so polyester can withstand acid medium erosion;In alkaline medium, polyester has poor alkali resistance because it forms resonant stable carboxylate anion and hydrolysis becomes irreversible.The carboxyl group at the end of the polyester chain can react with alkaline earth metal oxides or hydroxides [such as MgO, CaO, Ca(OH)2, etc.] to expand the unsaturated polyester molecular chain and eventually form complexes.Molecular chain expansion can make the initial viscosity of the viscosity of the liquid resin 0.1 ~ 1.0pa ·s, in a short time, the viscosity increased to more than 103Pa·s, until it becomes a non-flowing, non-stick hand like gel.When the resin is in this state, it is not crosslinked, but can be dissolved in suitable solvent and has good fluidity when heated
So far, the unsaturated polyester (resin) matrix used as composite material at home and abroad is basically phthalic acid type (phthalic acid type), phthalic acid type (phthalic acid type), bisphenol A type and vinyl ester type, halogenated unsaturated polyester resin.
1, o-type unsaturated polyester, and between benzene type between unsaturated polyester phthalic acid and phthalate are isomers, by their synthesis of unsaturated polyester molecular chain type between neighbors benzene and benzene respectively, while their molecular chain chemical structure similar, but between benzene type unsaturated polyester compared with o-type unsaturated polyester, has the following features: (1) with two formic acid can be made between benzene type high molecular weight of isophthalic acid address unsaturated ester, the curing products has good mechanical properties, toughness, heat resistance and corrosion resistance;(2) phthalic acid polyester purity, resin is not residual phthalic acid and low molecular weight phthalic acid ester impurities;(3) of isophthalic acid polyester molecular chain ester bond under the protection of stereoscopic steric hindrance effect of isophthalic acid, phthalic acid ester bond of polyester molecular chain more vulnerable to water and other all kinds of corrosive medium, with isophthalic acid polyester resin made of glass fiber reinforced plastic in 71 ℃ saturated sodium chloride solution soak a year later still has a very high performance.
2.Compared with the chemical structure of o-phenol unsaturated polyacid and m-phenyl unsaturated polyester macromolecular chain, the distance between ester bonds in the chain which is easily damaged by hydrolysis increases, thus reducing the density of ester bonds.The space effect of bisphenol A unsaturated polyester and styrene copolymerization after curing is large, which ACTS as A shield and protection for ester groups and hinders the hydrolysis of ester bonds.The neopentyl group in the molecular structure, connected with two benzene rings, maintains the stability of the chemical melon, so this kind of resin has good acid resistance, alkali resistance and hydrolysis resistance.
3.Vinyl resin vinyl resin, also known as epoxy acrylic resin, is a new type of resin developed in the 1960s, which is characterized by the polymer with end-group unsaturated double bond.Vinyl resin has a good comprehensive performance: (1) due to the unsaturated double bond is located at the end of the polymer molecular chain, double bond is very active, curing is not affected by the space barrier, can be triggered by organic peroxide, through the adjacent molecular chain crosslinking curing, also can be with monomer styrene polycuring;(2) R group in the resin chain can shield the ester bond, improve the ester bond chemical resistance and hydrolysis resistance stability;(3) vinyl resin, per unit of the relative molecular weight of the ester bond less than the ordinary unsaturated polyester about 35% ~ 50%, so as to improve the resin hydrolysis stability in acid and alkali solution;(4) resin chain on the secondary hydroxyl and glass fiber or other fiber infiltration and bonding to improve the strength of composite materials;(5) epoxy resin main chain, it can be endowed with vinyl resin toughness, molecular chain in the ether bond can make the resin has excellent acid resistance.The variety and properties of vinyl resin vary widely with the raw materials used. The molecular structure can be designed according to the requirements of composite materials for the resin properties.
4. Halogenated unsaturated polyester halogenated unsaturated polyester is a kind of chlorinated unsaturated polyester synthesized from chlorinic anhydride (HET) as saturated dibasic acid (anhydride).Chlorinated unsaturated polyester resin has been used as a resin with excellent self extinguishing properties.But in recent years, studies have shown that unsaturated polyester resin chlorinated also has fairly good corrosion resistance, its corrosion resistance in some medium and bisphenol A unsaturated polyester resin and vinyl resin basic quite, and in some cases, such as wet chlorine in the corrosion resistance is superior to vinyl resin and bisphenol A unsaturated polyester resin.Hot wet chlorine reacts with unsaturated polyester resin after contact to produce chlorinated unsaturated polyester resin or "chlorine cream".The "chlorine cream" produced by bisphenol A unsaturated polyester resin and vinyl ester resin is soft. Wet chlorine can penetrate further through the "chlorine cream" layer (corrosion), but the "chlorine cream" produced by chlorinated unsaturated polyester is hard and can prevent further (corrosion) penetration of wet chlorine.Most of these resins contain benzene ring, but because the benzene ring has substituents, it is easy to be metabolized when entering the human body, so the harm to human body is greatly reduced compared with benzene, which is low toxicity.In addition, halogenated hydrocarbons are also toxic and harmful to human body and environment.
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.