Unsaturated polyesters, plastics

Uses. Phthabc anhydride is used mainly in plasticizers, unsaturated polyesters, and alkyd resins (qv). PhthaUc plasticizers consume 54% of the phthahc anhydride in the United States (33). The plasticizers (qv) are used mainly with poly(vinyl chloride) to produce flexible sheet such as wallpaper and upholstery fabric from normally rigid polymers. The plasticizers are of two types diesters of the same monohydric alcohol such as dibutyl phthalate, or mixed esters of two monohydric alcohols. The largest-volume plasticizer is di(2-ethylhexyl) phthalate [117-81-7] which is known commercially as dioctyl phthalate (DOP) and is the base to which other plasticizers are compared. The important phthahc acid esters and thek physical properties are Hsted in Table 12. The demand for phthahc acid in plasticizers is naturally tied to the growth of the flexible poly(vinyl chloride) market which is large and has been growing steadily. 

Performance Characteristics Polyester resins undergo a rapid transformation from a viscous Hquid to a soHd plastic state that comprises a three-dimensional cross-linked polymer stmcture. The level of polyester polymer unsaturation determines essential performance characteristics (Table 7), although polymer components can influence subtle features that affect thermal, electrical, and mechanical performance as defined by ASTM procedures. 

Unsaturated Polyester Resins. Unsaturated polyester resins are widely used as fiber-reinforced plastics, coating materials, tire cords, films, and casting or molding resins. Organic titanates such as TYZOR TPT, TYZOR TBT, or TYZOR TOT can be used to catalyze the preparation of the resins, which involves the polyesterification of a mixture of a- and p-unsaturated polybasic acids, such as maleic or fumade acid, and alicydic polybasic acids, such as adipic or isophthalic acid with polyhydroxyalcohols (489). 

Ellis and Rust solved this problem by dissolving the solid unsaturated polyesters in a liquid vinyl monomer, such as vinyl acetate.-2>12 However, the less volatile and more widely available styrene monomer was used instead of vinyl acetate for most of the fiber glass-reinforced "low pressure" polyester plastics that were produced during World War II and since that time. 

ISO 2535-1974(E), Plastics—Unsaturated polyester resins--Measurement of gel time at 25 C. BS 2782, Part 8, Method 835B, Determination of gelation time of polyester resins (manual method), 1980. 

Parkyn, B., Lamb, R, and Clifton, B. V. 1967. Polyesters, Vol. 2 Unsaturated Polyesters and Polyester Plasticizers, Iliffe, London, UK. 

SFS-ISO 1875 Plastics. Plasticized cellulose acetate. Determination of matter extractable by diethyl ether SFS-EN ISO 2554 Plastics. Unsaturated polyester resins. Determination of hydroxyl value (ISO 2554 1997)... 

PVC epoxy, polyester-isocyanate, unsaturated polyester, vinyl chloride-acetate copolymer, polyvinyl acetate, polyvinyl alkyl ether, ethylene-vinyl acetate, nitrile rubber-phenolic, neoprene rubber, polyisobutylene rubber, polyurethane rubber, and polysulfide rubber. See discussion in Section 6.3.28 concerning migration of plasticizers in PVC. 

ISO Plastics—Unsaturated polyester resins—Determination of reactivity at 80°C... 

Plastic Construction Ltd, 281 Plastizising, 2, 5, 253 Plastics Processing Industries Training Board, PPITB, 13, 19 Polybutadiene, 222 Polycarbonate, 5, 37, 38, 40, 57 Polychloroprene, 222 Polyester resins, unsaturated, 161 in HST, 191... 

ISO 3521 [330] Plastics - Unsaturated polyester and epoxy resins - Determination of overall volume shrinkage... 

Plastics Unsaturated-polyester resins - Measurement of gel time at ambient temperature 2001... 

Molybdenum Oxides. Molybdenum was one of the first elements used to retard the flames of ceUulosics (2). Mote recently it has been used to impart flame resistance and smoke suppression to plastics (26). Molybdic oxide, ammonium octamolybdate, and zinc molybdate ate the most widely used molybdenum flame retardants. Properties ate given in Table 5. These materials ate recommended almost exclusively for poly(vinyl chloride), its alloys, and unsaturated polyesters (qv). 

Polyols. Several important polyhydric alcohols or polyols are made from formaldehyde. The principal ones include pentaerythritol, made from acetaldehyde and formaldehyde trimethylolpropane, made from -butyraldehyde and formaldehyde and neopentyl glycol, made from isobutyraldehyde and formaldehyde. These polyols find use in the alkyd resin (qv) and synthetic lubricants markets. Pentaerythritol [115-77-5] is also used to produce rosin/tall oil esters and explosives (pentaerythritol tetranitrate). Trimethylolpropane [77-99-6] is also used in urethane coatings, polyurethane foams, and multiftmctional monomers. Neopentyl glycol [126-30-7] finds use in plastics produced from unsaturated polyester resins and in coatings based on saturated polyesters. 

Phthahc anhydride (1) is the commercial form of phthaUc acid (2). The worldwide production capacity for the anhydride was ca 3.5 x 10 metric tons ia 1993, and it was used ia the manufacture of plasticizers (qv), unsaturated polyesters, and alkyd resins (qv) (see Polyesters, unsaturated). Sales of terephthahc acid (3) and its dimethyl ester are by far the largest of any of the benzenepolycarboxyhc acids 14.3 x 10 t were produced in 1993. This is 80% of the total toimage of ah. commercial forms of the benzenepolycarboxyhc acids. Terephthahc acid is used almost exclusively for the manufacture of poly(ethylene terephthalate), which then is formed into textiles, films, containers, and molded articles. Isophthahc acid (4) and trimehitic anhydride (5) are commercial products, but their worldwide production capacities are an order of magnitude smaller than for terephthahc acid and its dimethyl ester. Isophthahc acid is used primarily in the production of unsaturated polyesters and as a comonomer in saturated polyesters. Trimehitic anhydride is used mainly to make esters for high performance poly(vinyl chloride) plasticizers. Trimesic acid (6), pyromehitic dianhydride (7), and hernimehitic acid (8) have specialized commercial apphcations. The rest of the benzenepolycarboxyhc acids are not available commercially. 

Styrene [100-42-5] (phenylethene, viaylben2ene, phenylethylene, styrol, cinnamene), CgH5CH=CH2, is the simplest and by far the most important member of a series of aromatic monomers. Also known commercially as styrene monomer (SM), styrene is produced in large quantities for polymerization. It is a versatile monomer extensively used for the manufacture of plastics, including crystalline polystyrene, mbber-modifted impact polystyrene, expandable polystyrene, acrylonitrile—butadiene—styrene copolymer (ABS), styrene—acrylonitrile resins (SAN), styrene—butadiene latex, styrene—butadiene mbber (qv) (SBR), and unsaturated polyester resins (see Acrylonithile polya rs Styrene plastics). 

---