Phenolic/epoxy novolac coatings

Phase 1 - Modified phenol epoxy novolac coating experience... 

Modified phenol epoxy novolac coating technology has been available commercially since 1994. This system provides a viable alternative to traditional materials of construction, and experience to-date has shown that the system is capable of performing in the most arduous of conditions within process equipment in the Oil and Gas Industry. 

To provide maximum corrosion resistance a two component phenolic/ epoxy novolac coating can be used. The phenolic coating provides resistance to high concentrations of acids, particularly to sulfuric acid at elevated temperatures. Refer to Table 18.13 for the compatibility of phenolic with selected corrodents. 

Phenol epoxy novolac 4.8 Castings, coatings, laminates... 

In order to satisfy the need to provide a coating system that has the ability to bridge cracks and provide improved corrosion resistance, medium build coating systems have been developed. The phenolic/epoxy novolac system is capable of bridging cracks and providing outstanding corrosion resistance. 

Materials. Epoxy novolac, DEN-431, obtained from Dow Chemical Co. was selected as the epoxy component. A 3,3 -diazidodiphenyl sulfone synthesized in our laboratory (5) was used as the azide compound. Poly(/7-vinyl phenol) obtained from Maruzen Oil Co. was used as the phenolic resin matrix. The coating solvent was cyclohexanone. The developer used in this study was 0.1 N tetramethylammonium hydroxide aqueous solution. 

Epoxy polymers (including epoxy novolacs) have been designed to meet most of these requirements and are almost universally used in such encap-sulant applications. Epoxy polymers exhibit superior adhesion that in many cases eliminates the need for a barrier or junction coating. They have a low coefScient of thermal expansion low shrinkage and low injection velocity, which means that low transfer or injection pressures can be used. These polymers also possess excellent mechanical properties coupled with low moisture and gas permeability. Above all, they are cheap and readily available. Other transfer-molding materials used to a limited extent include silicones, phenolic materials, and even polyesters. Most molding formulations are highly filled (70-75%) with materials such as quartz, fused silica, short... 

Chem. Descrip. Phenol-based epoxy novolac acrylate blended with tri-methylolpropane triacrylate (50%) with MEFIQ inhibitor (500 ppm) Uses Epoxy-acrylic for free radical-cured formulations and composites, metal/paper/wood coatings, electronics, inks Features High reactivity high thermal resist. good chem. resist., adhesion, hardness, heat resist., abrasion resist., impact str., water resist. Properties Gardner 11 max. clear liq. vise. 15,000-20,000 mPa s acid no. 3 max. 

The primary resins used in this market are the radiation-curable epoxy acrylates, accounting for 60% of the resins used. A small amoimt of cycloaliphatic epoxies are also used in UV-curable inks and resists. Phenol and cresol epoxy no-volacs, and bisphenol A based epoxies are used in thermally cured formulations. The epoxy novolacs are used where higher heat resistance is needed such as in solder masks. Both free-radical and cationic-curable UV inks and colored base coats have grown rapidly because of the needs for higher line speeds, faster cleanup or line turnaround, less energy consumption, less capital for a new hne, and fewer emissions. 

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

DSC and DMA scans of, 18 778 Novolac epoxy resins, 10 349 Novolac resins, 15 163. See also Novolacs in coatings, 18 782 in fiber bonding, 18 792 from phenolic resin polymerization,... 

Resinous adducts, 10 394 Resinous odor, 3 229t Resins. See also Epoxy resins Lacquer resins Novolac resins Phenolic resins Resole resins Thermoplastic resins acidic cation-exchange, 12 191 advanced materials, 1 693 antilipemic agents, 5 141 aromatic glycidyl amine, 10 372—373 chromatographic, 14 383-384 for coatings, 7 95-107 derived from furfuryl alcohol, 12 271— 272... 

Ea, above and below Tg. Three case studies illustrate the range of applicability of the bending beam setup and factors contributing to the stress state. The first is a comparison of two polymers for interlayer dielectrics PMDA-ODA (pyromellitic acid dianhydride - oxydiamine) and a bis-benzocyclobutene. The second is of a neat epoxy resin commonly used for microelectronics encapsulation (epoxidized ortho-cresol novolac cured with a phenolic novolac). The third is a screen-printable polyimide coating used for protection of the integrated-circuit chip. An outline of our stress model is sketched, and example results are presented. 

Uses Accelerator for phenolic novolac and other epoxy cures highly active catalyst for PU elastomers, shoe soles, coatings ManufJDistrib. Air Prods. Aldrich BASF AG BASF Fluka SAF Bulk Chems. Schweizerhall Sigma... 

The number of epoxy groups depends upon the number of OH groups in the starting material and the extent of substitution on those groups with the chloroepoxypropane. Alkyl substituted phenols such as o-cresol can also be used to produce epoxies, and esterified novolac resins can be used in polyester coatings. 2,3-epoxypropyl ethers can also be produced fiom di- and trihydric phenols. 

Diglycidyl ethers of bisphenol A (DGEBA or Bis A epoxies) Diglycidyl ethers of bisphenol F (DGEBF or Bis F epoxies) -low-molecular-weight epoxy coatings Epoxy phenol or cresol novolac multifunctional resins... 

Alcohol-soluble non-heat-reactive types are low MW novolacs derived from phenol or cresols that are used in the preparation of novolac epoxy resins, epoxy curing agents, epoxy-phenolic systems, and powder coatings. 

Some examples of multifunctional epoxy resins other than epoxy phenol novolac resins are depicted in Figure 2.39 (b), (c) and (d). Triglycidylisocyanurate is a solid trifunctional epoxy cross-linker used in powder coatings, which provides a higher cross-link density and superior photochemical stability compared to BPA epoxy resins. The use of triglycidyl isocyanurate may present toxicity hazards. 

---