Phenolic resins recycling

Industrial Engineering Chemistry Research 39, No.2, Feb.2000, p.245-9 CHEMICAL RECYCLING OF PHENOL RESIN BY SUPERCRITICAL METHANOL... 

Oil filters -phenolic resins m [PHENOLIC RESINS] (Vol 18) -source of ferrous scrap [RECYCLING - METALS - FERROUS METALS] (Vol 20)... 

Electrical and electronic devices are made utilizing several various types of plastic materials, thus when discarded their waste is difficult to recycle. The plastics employed in housing and other appliances are more or less homogeneous materials (among others PP, PVC, PS, HIPS, ABS, SAN, Nylon 6,6, the pyrolysis liquids of which have been discussed above). However, metals are embedded in printed circuit boards, switches, junctions and insulated wires, moreover these parts contain fire retardants in addition to support and filler materials. Pyrolysis is a suitable way to remove plastics smoothly from embedded metals in electrical and electronic waste (EEW), in addition the thermal decomposition products of the plastics may serve as feedstock or fuel. PVC, PBT, Nylon 6,6, polycarbonate (PC), polyphenylene ether (PPO), epoxy and phenolic resins occur in these metal-containing parts of EEW. 

Alkenes with between 4 and 24 carbon atoms react with phenol to produce an unrefined phenol—alkylphenol mixture. This mixture is fed to the distillation train where the phenol is removed for recycle and the product is isolated. The product is then stored in heated tanks made of stainless steel or phenolic resin lined carbon steel. These tanks are blanketed with inert gas to avoid product discoloration associated with oxidation. 

Recycling waste bonded by means of phenolic-resin... 

Goto J and Santorelli M (2010), Recycling , in Pilato L, Phenolic Resins A Century of Progress, New York, Springer, 517-524. 

Phenolics are consumed at roughly half the volume of PVC, and all other plastics are consumed in low volume quantities, mosdy in single apphcation niches, unlike workhorse resins such as PVC, phenoHc, urea—melamine, and polyurethane. More expensive engineering resins have a very limited role in the building materials sector except where specific value-added properties for a premium are justified. Except for the potential role of recycled engineering plastics in certain appHcations, the competitive nature of this market and the emphasis placed on end use economics indicates that commodity plastics will continue to dominate in consumption. The apphcation content of each resin type is noted in Table 2. Comparative prices can be seen in Table 5. The most dynamic growth among important sector resins has been seen with phenoHc, acryUc, polyurethane, LLDPE/LDPE, PVC, and polystyrene. 

For large scale work the cost of the resin might be a major disadvantage unless it could be recovered. We have therefore taken a sample of resin filtered off after a reaction and reconverted it into the tribromide by addition of bromine. Reuse of this resin in a further reaction with phenol gave results which were very comparable with those obtained using the original resin. Therefore, recycling of the resin appears to be a viable possibility. 

Description Acetone and excess phenol are reacted by condensation in an ion exchange resin-catalyzed reactor system (1) to produce p,p BPA, water and various byproducts. The crude distillation column (2) removes water and unreacted acetone from the reactor effluent. Acetone and lights are adsorbed into phenol in the lights adsorber (3) to produce a recycle acetone stream. The bottoms of the crude column is sent to the crystallization feed pre-concentrator (4), which distills phenol and concentrates BPA to a level suitable for crystallization. 

Description Acetone and excess phenol are reacted in a BPA synthesis reactor (1), which is packed with a cation-exchange resin catalyst. Higher acetone conversion and selectivity to BPA and long lifetime are characteristic of the catalyst. These properties reduce byproduct formation and catalyst volume. Unreacted acetone, water and some phenol are separated from the reaction mixture by distillations (2-4). Acetone is recycled to the BPA reactor (1) water is efficiently discharged phenol is mixed with feed phenol and purified by distillation (5). The crude-product stream containing BPA, phenol and impurities is transferred to the ciystallizer (6), where ciystalline product is formed and impurities are removed by the mother liquor. Sep-... 

Phenol can be removed by weak-base resin (e.g., lonac AFP-329). The capacity of this resin is not affected by the neutral salt. Regeneration of the resin is performed by methanol, isopropanol, or dilute alkah. The use of alcoholic solvents allows the recovery of phenol as the free acid, because the alcohol can be stripped from the regenerant effluent stream, leaving the phenolic concentrate. The recovered alcohol can then be reclaimed and used for subsequent regenerations, and the phenol can be recycled back to the process stream. The use of dilute alkali allows the recovery of the phenol as the sodium salt. 

Containing Recycled Phenol-formaldehyde Resin as a Functional Filler. . 80... 

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