Phenohc resin

Furfuryl alcohol is shipped in bulk or dmms. Although not corrosive to metals, it is a powerful solvent and penetrant containers, tanks, lines, and valves need to be in good condition to avoid potential leakage. Furfuryl alcohol can be stored in containers lined with baked phenoHc resin coatings however, it should not be put in containers that are coated with lacquers, varnishes, or epoxy resins because it is an excellent solvent for many such coatings. 

Furfuryl alcohol alone, or in combination with other cross-linkable binders such as phenoHc reins, chemical by-products and pitch, catalyzed with acid, gives carbon yields of 35—56%. Furfural together with cyclohexanone, pitch, or phenoHc resins gives, under acid catalysis, yields of 35—55% carbon under basic catalysis yields of 5—50% are achieved. FurfuryHdeneacetone resins (13 and 14), catalyzed by acid or base, give carbon yields of 48—56 and... 

Eig. 6. Decomposition of polymers as a function of temperature during heating. A, polymethylene B, polytetrafluoroethylene C, silicone D, phenoHc resin ... 

Cork [61789-98-8] is an effective low cost charring ablator. In order to reduce moisture absorption and related poor performance, cork particles are often blended in a silicone or phenoHc resin. The result is a uniform ablative material in a sheet form that is easy to apply. 

Bond Type. Most bonded abrasive products are produced with either a vitreous (glass or ceramic) or a resinoid (usually phenoHc resin) bond. Bonding agents such as mbber, shellac, sodium siHcate, magnesium oxychloride, or metal are used for special appHcations. 

Shipment, Stora.ge, ndPrice. Tank cars and tank trailers, selected to prevent color formation, are of aluminum or stainless steel, or lined with epoxy or phenoHc resins dmms are lined with phenoHc resins. Flexible stainless steel hose is used for transfer. Because of butanediol s high freezing point (about 20°C) tank car coil heaters are provided. The U.S. Hst price for bulk quantities in 1991 was about 2.18/kg, but heavy discounting was prevalent for large contracts. 

Phenolic Resins. Phenohc resins (qv) are formed by the reaction of phenol [108-95-2] C H O, and formaldehyde [50-00-0] CH2O. If basic conditions and an excess of formaldehyde are used, the result is a resole phenohc resin, which will cure by itself Hberating water. If an acid catalyst and an excess of phenol are used, the result is a novolac phenohc resin, which is not self-curing. Novolac phenohc resins are typically formulated to contain a curing agent which is most often a material known as hexamethylenetetraamine [100-97-0] C H22N4. Phenohc resin adhesives are found in film or solution... 

Phenohc resins are the oldest form of synthetic stmctural adhesives. Usage ranges from bonding automobile and other types of brake linings to aerospace apphcations. These adhesives have a reputation for providing the most durable stmctural bonds to aluminum. Because of volatiles, however, and the need for high pressures, the phenohc resins are used less as adhesives than the epoxy resins. 

The amount and physical character of the char from rigid urethane foams is found to be affected by the retardant (20—23) (see Foams Urethane polymers). The presence of a phosphoms-containing flame retardant causes a rigid urethane foam to form a more coherent char, possibly serving as a physical barrier to the combustion process. There is evidence that a substantial fraction of the phosphoms may be retained in the char. Chars from phenohc resins (qv) were shown to be much better barriers to pyrolysate vapors and air when ammonium phosphate was present in the original resin (24). This barrier action may at least partly explain the inhibition of glowing combustion of char by phosphoms compounds. 

Eyrol 51 is a water-soluble Hquid containing about 21% phosphoms. It is made by a multistep process from dimethyl methylphosphonate, phosphoms pentoxide, and ethylene oxide. The end groups are principally primary hydroxyl and the compound can thus be incorporated chemically into aminoplasts, phenoHc resins, and polyurethanes. Eyrol 51, or 58 if diluted with a small amount of isopropanol, is used along with amino resins to produce a flame-retardant resin finish on paper used for automotive air filters, or for backcoating of upholstery fabric to pass the British or California flammabiHty standards. 

Syntactic Cellular Polymers. Syntactic cellular polymer is produced by dispersing rigid, foamed, microscopic particles in a fluid polymer and then stabilizing the system. The particles are generally spheres or microhalloons of phenoHc resin, urea—formaldehyde resin, glass, or siUca, ranging 30—120 lm dia. Commercial microhalloons have densities of approximately 144 kg/m (9 lbs/fT). The fluid polymers used are the usual coating resins, eg, epoxy resin, polyesters, and urea—formaldehyde resin. 

CeUular urea—formaldehyde and phenoHc resin foams have been used to some extent in interior sound-absorbing panels and, in Europe, expanded polystyrene has been used in the design of sound-absorbing doors (233). In general, cost, dammabUity, and cleaning difficulties have prevented significant penetration of the acoustical tile market. The low percent of redection of sound waves from plastic foam surfaces has led to their use in anechoic chambers (216). 

Types of internal enamel for food containers include oleoresins, vinyl, acryflc, phenoHc, and epoxy—phenoHc. Historically can lacquers were based on oleoresinous products. PhenoHc resins have limited flexibiHty and high bake requirements, but are used on three-piece cans where flexibiHty is not required. Vinyl coatings are based on copolymers of vinyl chloride and vinyl acetate dissolved in ketonic solvents. These can be blended with alkyd, epoxy, and phenoHc resins to enhance performance. FlexibiHty allows them to be used for caps and closures as weU as drawn cans. Their principal disadvantage is high sensitivity to heat and retorting processes this restricts their appHcation to cans which are hot filled, and to beer and beverage products. 

Epoxy phenoHc coatings either are made by blending of a soHd epoxy resin with a phenoHc resin or are the products of the precondensation of a mixture of two resins. A three-dimensional stmcture is formed during curing which combines the good adhesion properties of the epoxy resin with the high chemical resistance properties of the phenoHc resin. The balanced properties of epoxy phenoHc coatings have made them almost universal in their appHcation on food cans. 

The production of hexamethylenetetramine consumes about 6% of the U.S. formaldehyde supply (115). Its principal use is as a thermosetting catalyst for phenoHc resins. Other significant uses are for the manufacture of RDX (cyclonite) high explosives, in mol ding compounds, and for mbber vulcanisation accelerators. Some hexamethylenetetramine is made as an unisolated intermediate in the manufacture of nitfilotriacetic acid. 

The newer open-ceU foams, based on polyimides (qv), polyben2imida2oles, polypyrones, polyureas, polyphenylquinoxalines, and phenoHc resins (qv), produce less smoke, are more fire resistant and can be used at higher temperatures. These materials are more expensive and used only for special appHcations including aircraft and marine vessels. Rigid poly(vinyl chloride) (PVC) foams are available in small quantities mainly for use in composite panels and piping appHcations (see Elame retardants Heat-RESISTANTPOLYA rs). 

The procedure of forming copolymers dates back to the early 1940s when only phenoHc resins were avaHable. Copolymers were produced by bulk polymerization of phenol [108-95-2] and formaldehyde [50-00-0]. Because the resulting soHd product had the shape of the vessel in which polymerization... 

Strong" Acid Cation Excha.ngers. AH strong acid-type resins are made from styrene—DVB copolymers, with the exception of a minor quantity of phenoHc resin. Batch sulfonation using commercial strength sulfuric acid [8014-95-1] is common. 

The quantity of resin appHed to the reinforcing ply to achieve a state of full densification varies inversely with the laminating pressure. Therefore, high pressure laminates pressed at about 7 MPa (1000 psi) need only about 25—30% phenoHc resin in kraft paper, whereas low pressure (1 MPa = 145 psi) laminates need 50—60% resin in the reinforcing ply if all voids are to be filled in the final product. 

Glass-Based Grades. Grade G-3 is glass fabric with phenohc resin binder which shows high impact and flexural strength. It is used for thermal and mechanical apphcations and has good dimensional stabihty. 

Flame-Resistant Grades. Grade FR-1, paper-based laminates with a phenoHc resin binder, are similar in all properties to Grade XP, but so formulated to have at least a UL94 V-1 classification when tested according to UL94. 

In 1993, worldwide phenol production was more than 5.2 million metric tons (1). The predominant uses of phenol are in phenoHc resins (qv), bisphenol A, caprolactam (qv), aniline, and alkylphenols (qv). 

The most important commercial chemical reactions of phenol are condensation reactions. The condensation reaction between phenol and formaldehyde yields phenoHc resins whereas the condensation of phenol and acetone yields bisphenol A (2,2-bis-(4-hydroxyphenol)propane). PhenoHc resins and bisphenol A [80-05-7] account for more than two-thirds of U.S. phenol consumption (1). 

The largest outlet for phenol worldwide is phenoHc resins (qv). However, the growth rate of bisphenol A is higher than that of the other significant derivatives and is projected to become the principal use of phenol in the future (see Epoxy resins Polycarbonates). Table 6 shows the portion of world phenol demand by use and the anticipated growth rate of the uses. 

Phenohc resins are produced by the condensation of phenol or a substituted phenol, such as cresol, with formaldehyde. These low cost resins have been produced commercially for more than 100 years and in the 1990s are produced by more than 40 companies in the United States. They are employed as adhesives in the plywood industry and in numerous under-the-hood appHcations in the automotive industry. Because of the cycHc nature of the automotive and home building industry, the consumption of phenol for the production of phenohc resins is subject to cycHc swings greater than that of the economy as a whole. 

Some other phenol derivatives are somewhat local in appHcation. Eor example, aniline is produced from phenol at only two plants, one in Japan and one in the United States. Likewise, phenol is used in the production of nylon, via caprolactam (qv) or adipic acid (qv) by only one United States producer and one European producer. These markets, like the phenoHc resin and polycarbonate markets, are quite cycHcal. Thus, the entire phenol market tends to be cycHcal and closely tied to the housing and automotive markets. 

As a family of resins originally developed in the early twentieth century, the nature and potential of phenoHc resins have been explored thoroughly to produce an extensive body of technical Hterature (1 8). A symposium sponsored by the American Chemical Society commemorated 75 years of phenoHc resin chemistry in 1983 (9), and in 1987 the PhenoHc Mol ding Division of the Society of the Plastics Industry (SPI) sponsored a conference on phenoHcs in the twenty-first century (1). 

PhenoHc resins are prepared by the reaction of phenol or substituted phenol with an aldehyde, especially formaldehyde, in the presence of an acidic or basic catalyst. Their thermosetting character and the exotherm associated with the reaction presented technical barriers to commercialization. In 1900, the first U.S. patent was granted for a phenoHc resin, using the resin in cast form as a substitute for hard mbber (10). 

Early phenoHc resins consisted of self-curing, resole-type products made with excess formaldehyde, and novolaks, which are thermoplastic in nature and require a hardener. The early products produced by General BakeHte were used in molded parts, insulating varnishes, laminated sheets, and industrial coatings. These areas stiH remain important appHcations, but have been joined by numerous others such as wood bonding, fiber bonding, and plywood adhesives. The number of producers in the 1990s is approximately 20 in the United States and over 60 worldwide. 

Phenol. This is the monomer or raw material used in the largest quantity to make phenoHc resins (Table 1). As a soHd having a low melting point, phenol, C H OH, is usually stored, handled in Hquid form at 50—60°C, and stored under nitrogen blanket to prevent the formation of pink quinones. Iron contamination results in a black color. 

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