Specialty Thermoset Resins

There is also a wide range of TS resins for specialty uses. 

There are two major allyl plastics, diallyl phthalate (DAP) and diallyl isophthalate (DAIP). Both of these are widely used in fiber RP forms. The allyl plastics are usually compression or transfer molded performing well in automated equipment (Chapter 5). They retain their physical and electrical characteristics under prolonged exposure to severe environmental conditions. They have high heat and moisture resistance, excellent electrical performance, good chemical resistance, dimensional stability, and low creep. These plastics are used where they provide environmental resistances. 

Bismaleimides are resins with characteristics similar to those of epoxies, but with higher temperature resistance [204-232C (400—450F)]. They 

Furane resins are produced by self-condensation of furfiuyl alcohol with furfural. They offer possibly the best chemical resistance of any thermosetting resin in non-oxidizing conditions, and have excellent resistance to solvents. However, they also require acidic catalysts that give a complication in processing. 

PEAR is a TS originally discovered by Ashland Chemical. It has 50% higher modulus and tensile strength than epoxy and five times the toughness. It has better thermo-oxidative stability than bismaleimide (BMI) and samples have shown no weight-loss after 3800 h testing at about176C. 

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The most common and widely used thermoset molding compounds are classified as follows (a) alkyd, (b) allylic (diallyl phthalate), (c) amino (melamine and urea), (d) epoxy, (e) phenolic, (f) polyester, and (g) silicone. There may be other specialty thermoset resin materials used on specific applications. 

The global thermoset resins market is expected to reach as high as 95 million metric tons by 2016 (Axis Research Mind report 2012). Excluding the alkyd resins, which are used primarily in the coatings, commercially important major types of thermoset resins, altuig with their relative % market share, estimated from literature (Fosdyke and Starr 2002), can be categorized as follows Polyurethanes (31 %), PhenoUcs (18 %), Amino resins (18 %), Unsaturated polyesters (12 %), Epoxies and other specialty/high performance thermosets (12 %), such as silicones, polyimides, bismaleimides (BMl), cyanate ester thermosets, etc. 

Other binders such as petroleum pitch and thermosetting resins are used for specialty applications. 

Precipitated silicas are predominantly used as reinforcing fillers in elastomers and to a smaller amount as thixotropes and viscosity builders in thermoset resins. Their application to elastomers includes the new green tires pioneered by Michelin. A new generation of high-structure precipitated silicas is finding application in silicone rubber and many specialty plastics. Precipitated silica is the lowest price synthetic silica. 

Synthetic Resins. Various polymers and resins are utilized to produce some specialty carbon products such as glassy carbon or carbon foam and as treatments for carbon products. Typical resins include phenoHcs, furan-based polymers, and polyurethanes. These materials give good yields of carbon on pyrolysis and generally carbonize directly from the thermoset polymer state. Because they form Httle or no mesophase, the ultimate carbon end product is nongraphitizing. 

Commonly accepted practice restricts the term to plastics that serve engineering purposes and can be processed and reprocessed by injection and extmsion methods. This excludes the so-called specialty plastics, eg, fluorocarbon polymers and infusible film products such as Kapton and Updex polyimide film, and thermosets including phenoHcs, epoxies, urea—formaldehydes, and sdicones, some of which have been termed engineering plastics by other authors (4) (see Elastol rs, synthetic-fluorocarbon elastol rs Eluorine compounds, organic-tdtrafluoroethylenecopolyt rs with ethylene Phenolic resins Epoxy resins Amino resins and plastics). 

Thermosetting adhesives, such as epoxies, are the workhorses of the industry. However, there are persistent challenges from various higher-priced specialty resins. 

Carboset . [BFGoodrich/Spec. Polymers] Aciyic resin sol ns. thetmoplas-tic and thermoset film-forming resin used in protective metal coatings, paints, ceramics, adhesives, textiles, paper, leather, cosmetics, floor polishes, chemical specialties. 

This exceeded all expectations, since an annual growth rate of about 7% was expected and is predicted for 1979. The use of epoxy resins in flooring, paving and aggregates jumped 25% from 1977 to 1978. It appears that the epoxy resins will continue to be low-volume, specialty chemicals when compared to thermoplastics and the other thermosets, but they will continue to find applications in special areas. 

Uses Solvent for coatings, cleaners, inks, textile lubricants, urethane prod. plasticizer for flexible thermoset polyester polymer intermediate for polyesfer polyols for urefhanes, wef-sfr. paper resins, polyester resins specialty chemical intermediate Regulatory DOT nonregulated SARA nonreportable Properties Clear colorless liq., mild sweet odor sol. in alcohols, ketones, ethers, most hydrocarbons si. sol. in water and higher paraffinic hydrocarbons m.w. 159 sp.gr. 1.092 (20 C) dens. 9.09 Ib/gal vise. 2.4 cSt vapor pressure 0.2 mm Hg (20 C) f.p. -20 C b.p. 196-225 C acid no. 0.3 max. flash pf. (TCC) 100 C surf. fens. 35.6 dynes/cm 99% min. esfers... 

Uses Solvent for coatings, cleaners, inks, textile lubricants, urethane prod. plasticizer for flexible thermoset polyester polymer intermediate for polyester polyols for urethanes, wet-str. paper resins, polyester resins specialty chemical intermediate... 

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