Polyester resin Coating

Co-Rexyn Polyester resins, coatings, pastes Interplastic... 

Polyester resin coatings are synthesized with components that introduce unsaturation into the polymer chain (—C=C—). The paint is manufactured by mixing a dissolved polyester resin in styrene monomer with pigment and reaction inhibitor. Additional styrene and peroxide are packaged in a separate container and are mixed with the paint when applied using a dual-headed spray gun. Peroxide serves as a radical polymerization initiator for the polyester resin with monomeric styrene and cross-linking. Figure 13.5 shows the chemical structure of an isophthahc polyester resin. 

CAS 112945-52-5 EINECS/ELINCS 231-545-4 Uses Filler for plastics, silicone rubber, cosmetics, pharmaceuticals, direct and indirect food applies., transparent polyester resin coatings, specialty RTV systems adsorbent, anticaking agent, glidant, suspending agent for pharmaceuticals thixotropy/suspension aid for acrylic enam-... 

Uses UV stabilizer, UV absorber for plastics, polyolefins, polyester resins, coatings U V absorber in cosmetics antioxidant, stabilizer for food-grade polymers... 

Almost all of the OX that is recovered is used to produce phthaUc anhydride. PhthaUc anhydride is a basic building block for plasticizers used in flexible PVC resins, for polyester resins used in glass-reinforced plastics, and for alkyd resins used for surface coatings. OX is also used to manufacture phthalonitrile, which is converted to copper phthalocyanine, a pigment. 

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

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. 

Trimethyl-l,3-pentanediol (7) is a white, crystalline soHd. It is used in surface coating and unsaturated polyester resins. It also appears promising as an intermediate for synthetic lubricants and polyurethane elastomers and foams. 

Other minor raw materials are used for specific needs. Eumaric acid [110-17-8] the geometric isomer of maleic acid, is selected to maximize thermal or corrosion performance and is the sole acid esterified with bisphenol A diol derivatives to obtain optimum polymer performance. CycloaUphatics such as hydrogenated bisphenol A (HBPA) and cyclohexanedimethanol (CHDM) are used in selective formulations for electrical apphcations. TetrahydrophthaUc anhydride [85-43-8] (THPA) can be used to improve resiUence and impart useful air-drying properties to polyester resins intended for coating or lining apphcations. 

Synthetic Applications. Oxazolines, which ate synthesized as indicated above, have been utilized in many different appHcations (25). When used in resin formulations, AMP, AEPD, and TRIS AMINO can incorporate the oxazoline stmeture into the polymer stmeture (26). Because they ate polyols, both AEPD and TRIS AMINO can be used in polyester resin modification. Oxazoline alkyd films ate characterized by improved performance, particularly salt-spray resistance and gloss (see Alkyd resins Coatings, special purpose, high performance). 

Unsaturated Polyester Resins (UPR). The principal uses are in putty, coatings, and adhesives. Glass-reinforced UPR is used for marine, constmction, and vehicle materials, as weU as for electrical parts. 

OC-Methylstyrene. This compound is not a styrenic monomer in the strict sense. The methyl substitution on the side chain, rather than the aromatic ring, moderates its reactivity in polymerization. It is used as a specialty monomer in ABS resins, coatings, polyester resins, and hot-melt adhesives. As a copolymer in ABS and polystyrene, it increases the heat-distortion resistance of the product. In coatings and resins, it moderates reaction rates and improves clarity. Physical properties of a-methylstyrene [98-83-9] are shown in Table 12. 

Materials are also blended with VDC copolymers to improve toughness (211—214). VinyHdene chloride copolymer blended with ethylene—vinyl acetate copolymers improves toughness and lowers heat-seal temperatures (215,216). Adhesion of a VDC copolymer coating to polyester can be achieved by blending the copolymer with a linear polyester resin (217). 

Trimethylolpropane (TMP), the reduced crossed aldol condensation product of //-butyraldehyde and formaldehyde, competes in many of the same markets as glycerol (qv) and pentaerythritol. The largest market for TMP is as a precursor in unsaturated polyester resins, short-oil alkyds, and urethanes for surface coatings (see Alkyd resins). 

Unsaturated polyester resin powders can provide a colored and finished exterior molded surface or a finish ready for painting. Normally, a primer/sealer must be appHed to molded articles prior to painting. In addition to the unsaturated polyester resin, multifimctional unsaturated monomers such as triaHyl cyanurate (TAC) [101-37-1] or diaHyl phthalate (DAP) [131-17-9] suitable peroxide initiators (qv) or mixtures thereof, and mold release agents (qv) are used to formulate the coating powder (46). 

Acryflc coating powders have achieved some success in Japan utilizing resins having gflcydyl methylacrylate functionality cured with C q—0 2 dicarboxyflc acids (49). Hybrid polyester—acryflc coating powders have also been reported in which an acid functional polyester resin coreacts with a glycidyl-containing acryflc polymer (50). Hydroxyl functional acryflc resins cured with blocked isocyanates have also been available for many years in the United States and achieved some commercial success as appliance finishes. 

SiHcone resins provide coatings having outstanding heat resistance and exterior durabiHty. The cost is relatively high but for specialized appHcations these resins are important binders (64). Silicone-modified acryHc and polyester resins provide binders having intermediate durabiHty properties and cost. Fluorinated polymers also exhibit outstanding durabiHty properties. High cost, however, limits appHcabiHty. 

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