Epoxy Vinyl Ester Resins

Dow Plastics manufactures a range of Derakane epoxy vinyl ester resins and the simplest is made by reacting low molecular weight epoxides with either AA or MAA to produce a chain structure  

The polymers have similar characteristics to epoxide resins, but because they have terminal CH2=C— groups, the products can be crosslinked with vinyl monomers like styrene that are activated with peroxide curing systems such as  

A conventional bisphenol-A polyester resin has ester links and double bonds throughout the molecule, whereas the vinyl ester resin has only two of each per molecule situated at either end of the chain. This reduced number of ester links accounts for the improved chemical resistance, whilst the reduced number of double bonds produces a more resilient structure. 

Derakane 411 is the Dow product made from bisphenol-A and the presence of the epoxy group confers additional resistance to alkalies. It can be pre-reacted with epoxy-novalacs forming (Derakane 470) with a higher temperature performance and improved resistance to acids. 

A brominated bisphenol-A (DerakaneSlO) confers the maximum degree of fire retardancy, whilst a rubber modified version (Derakane8084) imparts greater toughness and higher elongation. 

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Epoxy system curing profile, 10 17-18 Epoxy systems, post-cure for, 10 423 Epoxy vinyl ester composites, 10 452 Epoxy vinyl ester resins, 10 349 Epoxy vinyl esters, 10 383 Eprosartan, 5 187... 

FRP materials are made up of the polymer and reinforcing fibers. The polymer is typically a thermoset polymer thermoplastics can be used as well. Some typical thermoset polymers used are epoxy resins, unsaturated polyester resins, epoxy vinyl ester resins, phenolic resins, and high performance aerospace resins such as cyanate esters, polyimides, and bismaleimides. These resins... 

For commodity applications, there are four major classes of resins that are used in FRP applications. They are phenolic resin, epoxy resin, unsaturated polyester resin, and epoxy vinyl ester resins. A more complete description of these types of resins and their many variations can be found in Handbook of Thermoset Plastics. This is not a comprehensive list of resins used in composite manufacture, as commodity materials like polyurethanes and isocyanurate resins are sometimes used as well to make FRP parts. However, these materials are not covered in this chapter owing to their limited use, but, the principals of fire safety that apply for the resins described subsequently apply to these materials as well. 

Epoxy vinyl ester resins are a special class of unsaturated resin. This resin is made by capping an epoxy resin with methacrylic acid and then dissolving in styrene monomer to the desired viscosity. This gives mechanical properties similar to epoxy resins, but the processibility (low viscosity allowing for resin infusion processes) of an unsaturated polyester resin. As with unsaturated vinyl esters, the most common fire retardant vinyl ester resin is based on a resin made from a halogenated system, tetrabromobisphenol A. The level of bromine in the resin and the presence of antimony will determine the fire performance of the resin. These resins are normally used for corrosion resistant equipment or when fire performance and high mechanical properties are required. It is very difficult to get a low smoke value with a brominated vinyl ester resin again due to the fact that bromine... 

Two resins were used to do the first study on laminate construction. The first was a brominated epoxy vinyl ester resin with antimony pentoxide and the second was a brominated unsaturated polyester resin. They were both promoted to cure at room temperature with methyl ethyl ketone peroxide catalyst. The panels were then postcured at 250°F (121°C) for 8 h. Panels were prepared that varied in glass content from 25% to 70% and panel thickness varying from 0.05 in. to 0.25 in. and were tested at the same testing facility. A summary of the FSI test data for the first set of panels tested are shown in Figures 23.1 and 23.2. This graph in Figure 23.1 plots the FSI value versus the panel thickness. This data would indicate that the thickness of the test panel has no effect on the measured... 

Waste incineration requires sophisticated scrubbers to contain corrosive volatiles which are in contact with the scrubber wall at elevated temperatures reaching 220°C. " Glass mat reinforced novolac epoxy vinyl ester resins have good performance in this application except that they are subjected to thermal stress due to the temperature difference between surface and wall, and they frequently crack. In order to improve performance, a two layer laminate was produced. The base layer is composed of resin reinforced with glass mat. The resin contains 15-20% graphite filler. The surface layer contains 100 g/m" of carbon fiber. The presence of these two fillers helps to distribute heat more evenly throughout the layer of laminate and prevents cracking even under extreme conditions. "... 

Uniaxial tensile tests have been performed for four-ply and one-ply composites based on glass plain-weave reinforcement — Table 2.3. The composites are produced by resin infusion moulding using Dow Derakane 8084 Epoxy-Vinyl Ester resin. The weave architecmre is slightiy unbalanced exhibiting different crimp in warp and weft directions. The lay-up of four-ply composite has been balanced. 

Thermosetting resins Unsaturated polyesters phenol formaldehyde urea formaldehyde melamine formaldehyde epoxies vinyl ester resins cyanate ester resins bismaleimides certain polyimides... 

Epoxy vinyl ester resins are the resin of choice for industrial corrosion-resistant GRP equipment and the leading supplier is the Dow Chemical Company, with its brand name of Derakane . Some properties of various resin families are given in Table 9.1. 

In all cases, the resins used were Derakane epoxy vinyl esters (Fig. 9.4). In 64% of the cases the resin was one of the higher temperature type, that is an epoxy novolac vinyl ester resin (Derakane 470). This resin is particularly effective in containing acids and organic solvents. Its HDT of 150°C renders it the resin of choice for the higher temperature applications. Bisphenol A epoxy vinyl ester resins (Derakane 411) were used for 25% of the vessels, in particular for the high pH caustic and hypochlorite streams. The brominated epoxy vinyl esters (Derakane 510) were used for the remainder (11%) of the GRP vessels. These resins are important when both fire... 

The raw gas contains humid mixtures of SOj and SO3 and condensing sulfuric acid at temperatures of 80-100°C. The cleaned gas contains the same contaminants, but at much lower concentrations [6]. Both duct systems have been successfufly manufactured from GRP using an acid-resistant novolac epoxy vinyl ester resin. Large diameters are often used for... 

Recent research by Bergman [8] at the Swedish Corrosion Institute has demonstrated that in the gas/acidic sections of absorbers, novolac epoxy vinyl ester resins associated with acid-resistant glass types perform best, while in the high pH liquid-containing section, bisphenol-A epoxy vinyl... 

Significant cracking to a depth of 3-5 mm was found in the total circumferential area at the first and second spray nozzle levels, ft would have been only a matter of time, possibly another one to two more years, before the part of the structure exposed to high temperatures had failed. But the Derakane 470 novolac epoxy vinyl ester resin had held at temperatures far beyond its design limit. 

Figure 9.18 Gratings made by a contact moulding method using a bisphenol A epoxy vinyl ester resin and its flame retardant, brominated equivalent. It was installed at the Enichem plant at Gela...

Figure 9.19 Walkway, handrails, stairwells, cable trays and safety cages were made at the Dow Stade membrane chlorine plant using epoxy vinyl ester resin. Chemical environments include sodium hydroxide, sodium hypochlorite and brine...

Figure 9.19 shows an installation at the Dow Stade membrane chlorine plant. It was built in 1996 by Techno Composites Domine Gmbh, using Bekaert profiles made with Derakane 440-40 epoxy vinyl ester resin. The installation includes stairwells, handrails, walkways cable trays and safety cages. GRP and pultruded profiles in particular were used for their resistance to the chemicals being handled - notably sodium hydroxide, sodium hypochlorite and brine. Their electrical resistance was also a factor in this electrochemical plant [11]. 

S Youd and P Harrison, Epoxy vinyl ester resins - From the first 25 years to the 21st Century , ISth International Composites Conference 1992, British Plastics Federation, London, 1992. 

Britten, a New Zealand motorcycle company, has used a composite subchassis made of carbon fiber/Kevlar Derakane epoxy vinyl ester resin laminate for their Britten VIOOO racing machine.The Aprila 250 uses cfrp wheels molded in two halves from a 2x2 HS twill... 

Wood Science Technology (WSTI), Corvalis, Oregon, USA—Zoltec and Dow Chemical Co. have an agreement with WSTI, who will use WSTI patents and manufacture thin sheets of composite laminate for the reinforcement of engineered lumber products using Zoltek s carbon fiber and Dow s Derakane epoxy vinyl ester resins. 

Densetec, HDPE sheet. Polymer Industries Deplastol, Viscosity depressant Henkel Corp. D.E.R., Epoxy resins, Dow Plastics Derakane, Epoxy vinyl ester resins, Dow Plastics... 

DERAKANE Epoxy Vinyl Ester Resins Chemical Resistance and Engineering Guide. Dow Chemical... 

While epoxy resins are known for excellent chemical resistance properties, the development and commercialization of epoxy vinyl ester resins in the 1970s by Shell and Dow offered enhanced resistance properties for hard-to-hold, corrosive chemicals such as acids, bases, and organic solvents. In conjimction with the development of the structural composites industry, epoxy vinyl ester resin composites found applications in demanding environments snch as tanks, pipes and ancillary equipment for petrochemical plants and oil refineries, automotive valve covers, and oil pans. More recently, epoxy and vinyl esters are used in the construction of windmill blades for wind energy farms. Increasing requirements in the composite industries for aerospace and defense applications in the 1980s led to the development of new, high performance multifunctional epoxy resins based on complex amine and phenolic structures. Examples of those products are the trisphenol epoxy novolacs developed by Dow Chemical and now marketed by Huntsman (formerly Ciba). 

Darvan Dispersing agents, Vanderbilt Dechlorane Plus Fire-retardant additive. Occidental D.E.H. Epoxy catalyst resins, Dow Delrin Acetal resin, DuPont Delrin ST Tough acetal homopolymer, DuPont D.E.N. Epoxy novolac resins, Dow Derakane Epoxy vinyl ester resins, Dow... 

A non-epoxy-based vinyl ester is simply a methacrylate terminated polyester. It has a reduced resistance to caustic and acids and can be used as a plastic composite binding resin in applications where high chemical resistance is not critical. Epoxy vinyl ester resins have not penetrated the automotive market because relatively inexpensive polyesters can meet most of the performance needs except chemical resistance. However, it is possible to imagine the introduction of epoxy vinyl ester resins into more corrosive or severe applications near the engine, batteries, external body parts, and so forth. 

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