What is unsaturated polyester resin and what varieties of unsaturated polyester resins are there?

What is called unsaturated polyester resin, unsaturated polyester resin what varieties
acid and alcohol in the acidic medium to produce esters, polyols and polyic acid reaction after the production of polyaethic resin. When there are more than two hydroxyls in the molecular structure, the cross-linking reaction between molecules can be produced, and the lower molecular weight is connected into large molecules, which have thermoso-solidity. Aolic acid resins used in the elephant coating industry are the result of saturated acid reactions containing more than two hydroxyl alcohols and more than two hydroxy acids
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. The polysynthetic resin obtained by the reaction of unsaturated binary alcohol or polyol with double bond is called unsaturated polyester resin; After the 1940s, it was widely used in glass glass steel production and coatings. Foreign unsaturated polyester resin raw materials have long been changed from food crops to petrochemical synthesis, so the price is the most straight synthetic resin. Polyester resin accounts for the largest proportion of glass and steel production. Polyester fiberglass is widely used in national defense engineering, weapons, construction, light industry and petrochemical corrosion protection.
unsaturated polyester resin varieties are very many, there are heat, fire, light, corrosion and other special-purpose varieties, the basic products are general-purpose unsaturated polyester resin (foreign general-purpose has been gradually replaced by a variety of special-purpose polyester). General-purpose polyester resin is the use of shunbutene glyceride, phosphorus benzoic acid, ethylene glycol, propylene glycol, a reduction of glycol and other raw materials, made by a shrink reaction. The ratio of binary acid to binary alcohol is matched by reactive theory, and binary alcohol is generally overdose by about 10%. During the reaction process, these alcohols and acids are bi-official group compounds, each pair of official energy group can form an ester bond, esterification reaction continuously, gradually forming a line chain molecule, while generating a molecule of water.
reaction is carried out continuously, generally up to 10 to 30 ester chains, divided into about 1000 to 2000; The shrink reaction is protected by nitrogen or carbon dioxide at a temperature of 200 degrees Celsius, and the reaction is more than 10 hours, so that the acid value reaches 30. When xylene solvents are added, dehydration by decompression can shorten the reaction time.
the polyester resin produced by the reaction is mixed with the cross-linked styrene monomer and sold as a finished product;
If the bisphenol A epoxy propane addition is used as a binary alcohol component, the unsaturated polyester resin produced by binary esterification has better corrosion resistance than the general-purpose unsaturated polyester resin. The general-purpose resin obtained with the ring-sealed key has the characteristics of toughness after molding. The resin obtained by acetic anhydride chain has the characteristics of hardness and rigidity after molding. A heat-resistant resin resistant to temperatures of 260 degrees Celsius can be used as a crosslinker with a melamine monomer. Resins obtained from heF and glycol esterification with tetrachlorobenzene or HCB diode have fire resistance, and the addition of the flame retardant molybdenum oxide powder can also improve refratary resistance.
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