Bisphenol-A epoxy vinyl ester

Bis-A EpVE = Bisphenol-A epoxy vinyl ester (Derakane 411), Nov EpVE = Novolac epoxy vinyl ester (Derakane 470), Isopoly = Iso Polyester, Orthopoly = Orthopolyester, Ep MDA = Bisphenol-A epoxy resin cured with methylene dianiline. 

In the case of epoxies using MD A or IPD hardeners, a minimum of 2-3 h at 120°C is required to achieve good corrosion, mechanical and heat resistant properties. For polyesters and bisphenol A epoxy vinyl esters, a minimum cure of 2-4 h at 70-80°C should be sufficient to ensure optimal corrosion properties. For novolac-based vinyl esters, 4h at 100°C will optimize the corrosion properties but to achieve a HDT of 150°C then a cure closer to this temperature is required. 

Most design norms or standards advise that composites should not be used at temperatures higher than 20°C below the HDT of the resin used. This means that polyesters can be used up to about 70°C, bisphenol A epoxy vinyl esters to 80-90°C and novolac epoxy vinyl esters to 130°C. This principle works quite well for polyesters and bisphenol A epoxy vinyl esters. It is rare for applications in the chemical process industry to require temperatures above 80-90°C. While theoretically it is possible to use novolac epoxy vinyl esters up to 130°C, there are actually very few applications requiring stability above 110°C. 

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... 

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...

Vinylesters are unsaturated, hence thermosetting, resins, prepared by the reaction of a monofunctional unsaturated acid, e.g. methacrylic, acrylic, crotonic or cynnamic acid, with a bisphenol diepoxide. This type of structure is referred to as bisphenol-A epoxy vinyl ester (Fig. 4.3(a)). The structural difference, which at least partially justihes the improved chemical and mechanical properties of vinylester, is the presence in vinylesters of reactive double bonds at the ends of the chains only, while unsaturated polyester resins have the reactive double bonds distributed throughout the chains. 

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... 

Table 2 Cone calorimeter data for modified bisphenol A vinyl ester (Mod-Bis-A Vinyl Ester), bisphenol A novolac vinyl ester (Bis-/Novolac Vinyl Ester) and methylenedianiline and benzyldimaine (BDMA) cured epoxy resins and their intercalated nanocomposites ( ) containing 6% dimethyl dioctadecylammonium-exchanged montmorillonite. Heat flux = 35 kW/m, HRR = heat release rate, MLR = mass loss rate. He = heat of combustion, SEA = specific extinction area [121]...

Vinyl esters (also referred to as epoxy acrylates) are prepared from the epoxies (such as the Bisphenol A or novolac based epoxies) reacted with methacryhc acid leaving pendant vinyl groups capable of crosshnking as noted below. Styrene is typicaUy added in commercial apphcations to yield lower viscosity and lower cost [920]. Carboxy terminated butadiene-acylonitrile ohogmers (CTBN) can be added to improve toughness. The structure of a Bisphenol A based vinyl ester is ... 

Another comparative study analyzed the effect of different curing strategies on the composite properties, when samples made of same amounts of woven glass fabric and an epoxy-vinyl ester (Derakane 510A— brominated bisphenol A-based vinyl ester) were single-sided UV-cured in the presence of 2 % bisacylphosphine oxide (BAPO) as photoinitiator, or thermally cured in the presence of 1.2 % benzoyl peroxide (BPO) [191]. Data obtained for flexural strength indicated the laminates had comparable characteristics and the procedure may be subjected to further optimization [192]. 

The tensile adhesion values show no correlation with the extent of corrosion the bisphenol A epoxy cured with a polyamide amine showed blistering, which represents a complete loss of adhesion. The polyester showed cohesive failure at less than 1000 hours of exposure, so a true adhesion value could not be determined. The other epoxies and the vinyl ester all had values in the 150-200 psi range, with no apparent relationship to the amount of corrosion. 

The best performing coatings were the vinyl ester, the bisphenol A epoxy cured with an aliphatic amine, and a novolac epoxy cured with a mixed aromatic/cycl oal i phati c amine. The saturated polyester, and a bisphenol A epoxy cured with a polyamide amine showed significant deterioration of the coating material in the acid, and corrosion of the underlying steel. Two types of novolac epoxies cured with aromatic amines showed intermediate performance. 

Generally, a vinyl ester could be classified as methyl acrylic acid extended bisphenol A epoxy, acrylic acid bisphenol E epoxy, a bisphenol F novolac epoxy, or a urethane modified ester. Each will provide a different degree of resistance. Vinyl ester lining systems have been successfully applied to provide protection to stack liners, ducting, scrubbers, thickener tanks, and other vessels in FGD plants, stacks and ducts, electrostatic precipitators, and bag house environments. 

Other additives and stabilisers are therefore used, using similar technology to that developed with TS polyesters, but large quantities must be used with vinyl esters that may impair the corrosion-resistant properties of these resins (which is one of the main reasons why they are used). Producers have therefore developed special additives. A typical solution is a version of a bisphenol-A epoxy VE, developed in... 

Hydrogenated-Bisphenol A Isophthalic PET Epoxy Vinyl esters Eurans Phenolics... 

Vinyl ester resins derived from bisphenol-A epoxies are suitable for chemical resistant FRP structures, filament winding and pultrusion with failure elongations of about 6%. 

Vinyl esters are thermosetting resins that consist of a polymer backbone with an acrylate or methacrylate termination. The backbone component of vinyl ester resins can be derived from epoxide, polyester or urethane but those based on epoxide resins have most commercial significance. Bisphenol A epoxy formed vinyl esters were designed for chemical resistance and commonly formulated for viscosity for use in filament winding of chemical containers. Typically styrene is used as a reactive dilutent to modify viscosity. Phenolic novolac epoxies are used to produce vinyl esters with higher temperature capability and good solvent resistance, particularly in corrosive environments, and their FRP composites have demonstrated initial economy and better life cycle costs compared with metals. 

Bisphenol A epoxy-based vinyl ester resins containing 50 wt% styrene. Vinyl ester resins containing 40 wt% styrene. 

Alpha Owens-Coming offers a flame retardant vinyl ester resin that meets ASTM 84 Class 1 flame spread and smoke rating. The resin is a highly brominated bisphenol-A epoxy based vinyl ester. It provides a unique combination of good flame and smoke resistance and inherently good mechanical properties. The flexural strength of 34% glass composite is 5100 psi (35 MPa) and flexural modulus is 450 ksi (3.1 GPa). 

A = bisphenol A epoxy—aliphatic amine hardener 1 -B = bisphenol A epoxy—aromatic amine hardener 1 -C = bisphenol F epoxy (epoxy novolac) 2-D = polyester resin—chlorendic acid type 2- E = polyester resin—bisphenol A fumarate type 3- F = vinyl ester resin 3-G = vinyl ester novolac resin ... 

Tough, versatile, bisphenol-A epoxy based vinyl ester resins dissolved in styrene offering outstanding mechanical properties and excellent resistance to cracking, crazing, chemicals and heat, for use in hand-lay, spray/projection lamination, filament winding and pultrusion. Available in standard and low monomer... 

A flame retardant, unaccelerated, non-thixotropic vinyl ester (dimethacrylate ester of a brominated bisphenol-A epoxy) which with the addition of 3% antimony trioxide can achieve a flame spread rating of less than 25 (ASTM E-84). 

A preaccelerated and thixotropic epoxy vinyl ester (dimethacrylate ester of bisphenol-A epoxy) offering outstanding mechanicals, superior toughness and fatigue resistance. 

An unaccelerated bisphenol epoxy vinyl ester for pipe and tank construction offering corrosion-resistance under a wide variety of acid and alkaline conditions, c. 500 e. See manufacturers recommendations re. accelerator/catalyst additions offering variable gel time. 

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