Substituted heat-reactive resin

Substituted heat-reactive resins are most widely used in contact-adhesive appHcations and, to a lesser extent, in coatings (77,78) -butylphenol, cresol, and nonylphenol are most frequendy used. The alkyl group increases compatibiHty with oleoresinous varnishes and alkyds. In combination with these resins, phenoHcs reduce water sensitivity. Common appHcations include baked-on and electrical insulation varnishes, and as modifiers for baking alkyds, rosin, and ester gum systems. Substituted heat-reactive resins are not used for air-dry coatings because of theh soft, tacky nature in the uncured state substituted nonheat-reactive phenoHcs are the modifying resin of choice in this case. 

Substituted heat-reactive resins, 18 782 Substituted isoquinolines, 21 208 Substituted nickel carbonyl complexes, 17 114... 

Substituted and Heat Reactive. The third class, substituted and heat-reactive resins, are made by using para-substituted phenols where the substituent is a four-carbon or higher group such as tert-butyl, tert-octyl, and phenyl. Small amounts of ortho-substituted phenols and unsubstituted phenols are sometimes coreacted but, in general, the functionality is 2, and only linear molecules are formed. They are brittle solids that do not form films. The substituent makes the resins less polar and hence they are soluble in ketones, esters, and aromatic hydrocarbons, with limited solubility in alcohols and aliphatic hydrocarbons. The phenolic resins based on longer chain aliphatic phenols are more compatible with drying oils, alkyds, and rubbers. 

Phenolic Dispersion Particulate Nature and Molecular Weight. Phenolic dispersions of the BKUA-2260 type are solvent free, gum arabic stabilized dispersions of heat reactive resins prepared from the condensation of formaldehyde with variously substituted phenolic monomers. A typical set of properties is shown in Table 4. 

Aqueous dispersions are alternatives to solutions of Hquid and soHd resins. They are usuaUy offered in 50% soHds and may contain thickeners and cosolvents as stabilizers and to promote coalescence. Both heat-reactive (resole) and nonheat-reactive (novolak) systems exist that contain unsubstituted or substituted phenols or mixtures. A related technology produces large, stable particles that can be isolated as discrete particles (44). In aqueous dispersion, the resin stmcture is designed to produce a hydrophobic polymer, which is stabilized in water by an interfacial agent. 

Phenolic resins are well known for their contribution in improving hardness, gloss, and water and chemical resistance in oleoresinous varnishes. Those based on p-alkyl-substituted phenols and with heat-reactive methylol groups have also been incorporated into alkyd resins. The reaction has not been well smdied. Presumably, the methylol group would react with the unsaturation functionality on the fatty acid chain to form the chroman stmcture, similar to what is believed to have occurred in the varnish. Etherification between the methylol group and free hydroxyl of the alkyd resin, catalyzed by the residual acidity in the resin, would be another possible reaction. 

Raw Materials Base-Catalyzed Reactions Acid-Catalyzed Reactions Classification of Phenolic Resins Unsubstituted and Heat Reactive Unsubstituted and Nonheat Reactive Substituted and Heat Reactive Substituted and Nonheat Reactive Applications... 

Phenolic resins can be divided between heat-reactive and nonheat-reactive resins and between resins made by using unsubstituted or substituted phenols. A review of the four resulting classifications follows. 

Oil-soluble non-heat-reactive novolac phenolic resins are produced from a substituted phenol such as/>-phenylphenol,/>-terf-butyl-phenol or p-nonylphenol with a lower ftp ratio. They are designed to be used with drying oil-based varnishes as hard components. Due to the availability of a larger variety of synthetic varnishes, the usage of such varnishes has been declining fast. 

The solubility of phenolic resins in different coating formulations is, however, affected by the type and chain length of substituent groups in the phenols. Depending on whether substituted or unsubstituted phenols are used, the phenolic resins can be further classified into two more groups of heat- and nonheat-reactive resins, having different applications. 

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. 

This formulation is laid down by electrophoresis over the material to be coated, acting as the cathode, and finally heat cured. The process requires molecules with chemical structure suitably designed for different applications, and the chemistry of Mannich bases may represent a convenient tool for preparing variously substituted derivatives. In fact, as depicted in Fig. 187, the reactive functions leading to the final crosslinked material may be bound to several different positions of the oligomeric epoxy resin. The Mannich derivatives of bisphenol A (572)2 " - > -2 and nonylphenol (573)202.2a i.2()6 con-... 

In summary of this section, it must noted that, in spite of numerous studies, nowdays we know very little about carbonyl hydrides and other substituted (mixed) carbonyls thermolysis in polymeric systems, as well as in reactive plastics. For example, in some experiments the decomposing metal carbonyls were placed into an epoxide resin heated up to the nanoparticles deposition on the forming polymer surface [121]. It is possible that the highly reactive metal particles in such systems can initiate the epoxy cycle cleavages followed by a three-dimensional space structure formation. Iron carbonyl being decomposed into polybenzimidazole suspension (in transformer oil at 473 K) forms the ferrum nanoparticles (1-11 nm) capable of polymer thermostabization [122]. 

Precaution Flamm. mod. fire risk can react with oxidizing materials Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and fumes NFPA Health 2, Flammability 2, Reactivity 0 Uses Solvent, stabilizer for shoe creams and floor waxes solvent in paint and lacquers, for oils, fats, waxes, resins, rubber, and asphalt substitute for turpentine cleaning machinery stain removal cleaning fluids lubricants motor fuel additive... 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating fumes NFPA Health 0, Flammability 1, Reactivity 0 Storage Store in cool, dry area hygroscopic Uses Intermediate in synthesis of org. compds., polyester and alkyd resins, polypropylene glycol solvent, emulsifier in paints, foods, pharmaceuticals substitute for... 

Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of SOx, Na20, and NOx HMIS Health 1, Flammability 0, Reactivity 0 Uses Artificial nonnutritive sweetener for foods, beverages, toothpaste, chewing gum, cosmetics, pharmaceuticals, tobacco sugar substitute oral care agent brightener in nickel plating antistat in textiles, plastics resin modifier/accelerator... 

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