Phenolic-epoxy

Epoxy-phenolic adhesives are made by blending epoxy resins with phenolic resins to improve the high-temperature capabilities of the standard epoxy resins. Developed in the early 1950s, they were the first high-temperature epoxy adhesives to become commercially available.2,3 

Epoxy-phenolic adhesives were developed primarily for bonding metal joints in high-temperature applications. Their first major application was to join major aircraft components. They are also commonly used for bonding glass, ceramics, and phenolic composites. Because of their relatively good flow properties, epoxy phenolics are also used for bonding honeycomb sandwich composites. 

These adhesives are generally based on blends of solid epoxy resins with resole-type phenolic resin. The epoxy resin component is often not the predominant component in the blend, depending on the end properties required. Phenolics are compatible with epoxy resins and will react through the phenolic hydroxyl group. The amount of phenolic resin used is generally much greater than that required to crosslink with the epoxy, so one can debate whether (1) the epoxy toughens the phenolic adhesive or (2) the phenolic increases the heat resistance of the epoxy. 

These adhesives are available as pastes, solvent solutions, and film supported on glass fabric. The adhesive films generally give better strengths than do liquid systems. Cure requires a temperature of 175°C for 1 h under 15- to 50-psi pressure. Most adhesives of this 

FIGURE 7.1 The effect of temperature on the tensile shear strength of modified epoxy-phenolic compared to other hybrid adhesives (substrate is aluminum).4 

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The aerodynamic wheel cover of claim 4, wherein said thermoset adhesives are selected from a group consisting of epoxies, phenolics, isocyanates, cyanoacrylates, acrylics or combinations thereof... 

Bisphenol F Resin. Bisphenol F [2467-02-9] epoxy resin is of the same general stmcture as the epoxy phenol novolaks. Bisphenol F is 2,2Emethylene bisphenol. Whereas the epoxy phenol novolaks vary from viscous Hquids to soHd materials, the bisphenol F resin has a low viscosity (ca 4 Pa-s (40 P)) and 165 epoxy equivalent weight. Its n value (degree of polymerization) is about 0.15 and crystallization, often a problem with low viscosity conventional bisphenol A resins, is reduced with the bisphenol F resin. 

Epoxy Phenol—Novolak Resins. Epoxy phenol—novolak resins [9003-36-5] are represented by the general idealized stmcture (3) whereby multifunctional products are formed containing a phenoHc hydroxyl group per phenyl ring in random para—para, ortho—para, and ortho—ortho combinations. 

The thermal stabiUty of epoxy phenol—novolak resins is useful in adhesives, stmctural and electrical laminates, coatings, castings, and encapsulations for elevated temperature service (Table 3). Filament-wound pipe and storage tanks, liners for pumps and other chemical process equipment, and corrosion-resistant coatings are typical appHcations using the chemically resistant properties of epoxy novolak resins. 

Epoxy Phenol Novolak Resins. Acute oral studies indicate low toxicity for these resins (49). Eye studies indicate only minor irritation in animals (49). The EPN resins have shown weak skin-sensitizing potential in humans. 

In addition to electrical uses, epoxy casting resins are utilized in the manufacture of tools, ie, contact and match molds, stretch blocks, vacuum-forrning tools, and foundry patterns, as weU as bench tops and kitchen sinks. Systems consist of a gel-coat formulation designed to form a thin coating over the pattern which provides a perfect reproduction of the pattern detail. This is backed by a heavily filled epoxy system which also incorporates fiber reinforcements to give the tool its strength. For moderate temperature service, a Hquid bisphenol A epoxy resin with an aHphatic amine is used. For higher temperature service, a modified system based on an epoxy phenol novolak and an aromatic diamine hardener may be used. 

Asphalt, unmodified Coal tar Coal tar— epoxy Coal tar— nretlianes Epoxy phenolic- baked Epoxy amine- cnred Epoxy ester Fnrfnryl alcohol Phenolics, baked Polyesters (nnsati i-rated) Polyvinyl cliloracetates Vinyl ester Urethanes Vinylidene cliloride Clilorinated rubber... 

The most common aerospace adhesives include nitrile epoxy systems, epoxy polyamides, epoxy phenolics, and various unmodified epoxies [18]. Polyimides... 

In addition to epoxy-phenolic adhesives three-part epoxy-phenolic-nitrile rubber systems are used in metal-metal edge joints and honeycomb constructions [208], These add toughness not available in most EP systems and improve peel strengths. When used on honeycomb, the NR-P is normally applied to the aluminum skin and the EP to the honeycomb for assembly. Service temperature limitations are those imposed by the NR-P part. 

Epoxy phenolic coatings These materials are also cured at relatively high temperatures and are made by the reaction of the epoxy resin with the phenolic resin. They are slightly less critical in application requirements, are less sensitive to curing conditions and can be applied in thicker coats. The best use for both these materials is as tank linings used for the storage or food products, drinks, etc. or for process plant, evaporators, etc. that contain boiling water. 

The epoxy-acrylic resin referred to above is a graft copolymer prepared by the polymerisation of acrylic monomers in the presence of the epoxy resin in such a way that grafting of the acrylic onto the epoxy takes place. Water dispersibility is achieved by neutralising carboxyl groups in the acrylic polymer chain with ammonia or amine. Amino or phenolic resins are used as crosslinkers. Alternatively, solvent-borne epoxy-amino or epoxy-phenolic lacquers can be used. 

Two-piece food cans may be made by a draw-redraw process, in which lacquer is first applied to and cured on sheet. Blanks are then cut from the sheet and the can is drawn from the blank in two or three stages. The lacquer deforms with the drawing process and lubricates the draw. It then becomes the interior protective coating. Although epoxy-phenolic solvent-borne lacquers are used, even better drawing properties are obtained from organosols. These are dispersions of colloidal polyvinyl chloride powder in solutions of other mixed resins in solvent, e.g. chosen from epoxy, polyester, vinyl and phenolic. 

Zone 5 acrylic, diallyl phthalate, epoxy, phenol-formaldehyde, TP polyester, and polytetrafluoroethylene. 

Certain plastics provide higher strength and stiffness a broad range of properties exit. Even though there are literally over 35,000 plastics available worldwide (for all plastic fabricating processes) only a few hundred are used in RPs. In turn only a few of those are predominantly used in most of the RPs. The thermoplastics (TPs) include principally nylons and polypropylenes, as well as polycarbonates, acetals and polyesters. Thermosets (TSs) include predominantly polyesters as well as epoxies, phenolics and urethanes. 

Thermoset Plastics Alkyd, amino resin, thermosetting acrylic resin, casein, epoxy, phenolic, polyester, polyamide, silicone. 

Enamels. The flexibility grades for the eight enamels (Table I) that were irradiated with 3-4 Mrad and 6-7.5 Mrad at 5, —30, and —90°C are shown in Table II. These data indicate that the epoxy-based enamels showed the best initial flexibility at — 90 °C and maintained their flexibility after irradiation. The preferred enamels were the epoxy phenolic with aluminum pigment, epoxy-wax and butadiene-styrene copolymer with aluminum pigment, and epoxy-wax with aluminum pigment. Tinplate adhesion before and after irradiation was satisfactory for the eight enamels. 

Extractives from Can Enamels. Earlier work reported by Pratt (1) showed that in a comparison between irradiation processing and thermal processing, no significant differences were found in the amount of extractives obtained from three commercial can enamels—epoxy phenolic, polybutadiene, and oleoresinous—in the presence of three aqueous... 

Following the same procedures described in the above-mentioned study, additional extractive data were obtained for the epoxy phenolic enamel that was irradiated at 4.7-7.1 Mrad at 25 and — 30 °C in the presence of distilled water, 3% acetic acid, and n-heptane. The changes in the amount of extractives resulting from the irradiation treatment are shown in Table IX. In the case of the water and acetic acid extractives, there was no change in either the chloroform-soluble fractions or the chloroform-insoluble fractions. In the case of the n-heptane extractives, the amount of extractives decreased when the irradiation temperature was reduced from +25 to — 30°C. Infrared spectra of the chloroform-soluble residues from the water and acetic acid extractives of the unirradiated and irradiated enamel were identical to the chloroform-soluble residues from the solvent blanks. In other words, the epoxy phenolic... 

The production test showed that the epoxy phenolic enamel was the preferred enamel for coating tinplate containers used in packaging irradiation-sterilized ham and beef. The preferred end-sealing compound for the same application was the blend of cured and uncured isobutylene-isoprene copolymer. 

The evaluation of the components of the tinplate container showed that the preferred enamel for irradiation processing was the epoxy phenolic the preferred end-sealing compound was the blend of cured and uncured isobutylene—isoprene copolymer. Component testing of tinplate and solder for possible changes in mechanical properties, microstructure, and corrosion resistance indicated that the radiation caused... 

Epoxy Phenolic-Epoxy (wt/wt) PHRR (KW/m2) Char Yield (%) Toxicity" (xl0 3)... 

Epoxidized novolacs, 411 Epoxy -phenol networks, 411-416 properties of, 413-416 Epoxy-phenolic reaction kinetics of, 413 mechanism of, 411-412 Epoxy structures, 414 e-Caprolactam, 174... 

Negative neighboring group effect, 456 Network formation, 13 Networks. See also Epoxy-phenol networks Phenohc networks phenolic-based, 376 polyester-based, 58-60 Neutral hydrolysis, 564-565... 

Phenol-epoxy reaction. See also Epoxy-phenolic reaction entries tertiary amine-catalyzed, 412 triphenylphosphine-catalyzed, 412 Phenol-formaldehyde novolac resin, preparation of, 429... 

Phthalazinone, 355 synthesis of, 356 Phthalic anhydride, 101 Phthalic anhydride-glycerol reaction, 19 Physical properties. See also Barrier properties Dielectric properties Mechanical properties Molecular weight Optical properties Structure-property relationships Thermal properties of aliphatic polyesters, 40-44 of aromatic-aliphatic polyesters, 44-47 of aromatic polyesters, 47-53 of aromatic polymers, 273-274 of epoxy-phenol networks, 413-416 molecular weight and, 3 of PBT, PEN, and PTT, 44-46 of polyester-ether thermoplastic elastomers, 54 of polyesters, 32-60 of polyimides, 273-287 of polymers, 3... 

Epoxy phenolic can coatings, 18 38 Epoxy phenol novolac (EPN) resins, 10 367-368 toxicity of, 10 461... 

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