Phthalic acid, propylene glycol, styrene

These polyesters are primarily copolyesters of propylene glycol with maleic and phthalic acids, dissolved in styrene monomer, and cured by peroxides activators (1, 4, 5). In a typical general-purpose polyester, a 103 excess of propylene glycol is cooked with an equimolar mixture of maleic and phthalic anhydrides for eight or more hours at 150-200°C to produce a viscous liquid polyester of 1000-5000 molecular weight. This is then partially cooled, diluted about 60/40 with styrene monomer, cooled to room temperature, and stored. It is later mixed... 

The basic patent (US Patent 3256219) indicates that the system is viable with conventional resins although special grades have been developed that are said to be particularly suitable. One example in the patent recommends the use of a polyester prepared using a maleic acid, phthalic acid and propylene glycol ratio of 2 1 33 and with an acid value of 40. To 500g of such a resin are added 10g of benzoyl peroxide and 167 g of styrene. Water 600 g is then stirred in at 5-10°C until a white creamy water-in-oil emulsion is obtained. A solution of 0.8 g of dimethyl-p-toluidine in lOOg of styrene is stirred into the emulsion and the resin is cast between plates and cured at 50°C. 

The properties of polymers formed by the step growth esterification (1) of glycols and dibasic acids can be manipulated widely by the choice of coreactant raw materials (Table 1) (2). The reactivity fundamental to the majority of commercial resins is derived from maleic anhydride [108-31-6] (MAN) as the unsaturated component in the polymer, and styrene as the coreactant monomer. Propylene glycol [57-55-6] (PG) is the principal glycol used in most compositions, and (o o)-phthalic anhydride (PA) is the principal dibasic acid incorporated to moderate the reactivity and performance of the final resins. 

The principal unsaturated acids used are maleic and fumaric. Saturated acids, usually phthalic and adipic, may also be included. The function of these acids is to reduce the amount of unsaturation in the final resin, making it tougher and more flexible. The acid anhydrides are often used if available and applicable. The dihydroxy alcohols most generally used are ethylene, propylene, diethylene, and dipropylene glycols. Styrene and diallyl phthalate are the most common cross-linking agents. Polyesters are resistant to corrosion, chemicals, solvents, etc. 

Phthalic anhydride, maleic anhydride, fumaric acid, isophthalic acid, ethylene glycol, propylene glycol, diethylene glycol, styrene Bulk polycondensation followed by free-radical-initiated chain polymerization Construction, automotive applications, marine applications... 

UP resins are soluble linear polycondensation products made from polyvalent -usually unsaturated - acids (e.g. maleic or fumaric acids) and bivalent alcohols (e.g. ethylene glycol and/or 1,2-propylene glycol). For special applications, it is common to substitute some of the a, -unsaturated dicarboxylic acids with phthalic acid and/or adipic acid. Seminal work on unsaturated polycondensation products made from maleic acid, maleic acid anhydride and glycols and on their copolymerisation with styrene is listed in [2.100],... 

PRINCIPAL COMPONENTS Prepolymers (oligomer) glycols (e.g., 1,3-propylene glycol), saturated acids (e.g., phthalic curhydride/acid), unsaturated acids (e.g., maleic anhydride/acid). Monomers styrene, a-methylstjrrene, methyl acrylate, methyl methacrylate, etc. 

General purpose resin is synthesized from 1,3 propylene glycol, phthalic anhydride, maleic anhydride and styrene. Phthalic and maleic anhydrides are at equimolar quantities. This resin is the most available one in the market and suitable for most of the cold-set lay-up work and some hot molding. The substitution of some maleic anhydride by adipic or sebacic acid... 

For dihydric alcohols, propylene, ethylene, and diethylene glycols and for acids-phthalic, adipic, and maleic anhydrides are commonly used. The use of maleic anhydride (or acid) is a necessity to incorporate available sites on the prepolymer backbone for the interaction with vinyl monomers. The most commonly used vinyl monomer is styrene while ct-methyl styrene, methyl acrylate, methyl methacrylate, acrylonitrile, diallyl phthalate, and triallyl cyanurate can be used as comonomers. 

---