Bisphenol A epoxy resin

Epoxy resins prepared from the reaction between bisphenol A (BPA) and epichlorohydrin are commercially the most important ones, covering around 80 to 85 % of the volume of epoxy resins used in the industry. Various BPA epoxy resins available on the market primarily differ in their MW, and can be categorized as  

Average number of repeat units (n) Melting point [°C] EEW Typical applications (coatings) 

1 Liquid 182-192 Floor coatings, solventless and high-solid ambient cure two-component coatings 

4 80-100 860-930 Powder coatings, Intermediate for epoxy ester resins 

9 100-120 1600-1950 Epoxy-phenollc/amino baking system (can coatings) 

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This low viscosity resin permits cure at low (70°C) temperatures and rapidly develops excellent elevated temperature properties. Used to increase heat resistance and cure speed of bisphenol A epoxy resins, it has utihty in such diverse appHcations as adhesives, tooling compounds, and laminating systems. A moleculady distilled version is used as a binder for soHd propellants (see Explosives and propellants) and for military flares (see Pyrotechnics). Its chief uses depend on properties of low viscosity and low temperature reactivity, particularly with carboxy-terminated mbbers. 

Table 6. Comparative Properties of Bisphenol A—Epoxy Resins Cured with Different Hardeners ...

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. 

Bisphenol A, epoxy resins from, 673 polymers from, 821 Bloch, Konrad Emil, 1084 Block copolymer, 1212 sy nthesis of, 1212... 

Weigh out 10.44 g of Bisphenol A epoxy resin into an aluminum weighing dish. 

Add the diethylenetriamine to the aluminum weighing dish containing the Bisphenol A epoxy resin. 

Used u> increase heat resistance and cure speed of bisphenol A epoxy resins, it has utility in such diverse applications as adhesives, looting compounds, and laminating systems. 

Epoxy acrylates are dominant oligomers in the radiation curable adhesives market. A bisphenol A epoxy resin is reacted with acrylic acid or methacrylate acid to provide unsaturated terminal reactive groups. The acrylic acid-epoxy reaction to make bisphenol A diacrylate destroys any free ingredients such as epichlorohydrin used to make the DGEBA epoxy starting raw material. 

For maximum heat resistance, pyromellitic dianhydride is often used. The composition and properties of metal-to-metal adhesives based on a combination of epoxy novolac and a bisphenol A epoxy resin have been described in Sec. 12.5.1. Depending on the cure temperature and the choice of amine curing agent, strength as high as 3000 psi at room temperature and over 1000 psi in the range of-55 to + 150°C is possible. 

The polyamidoamines are very high-viscosity liquids, some having viscosities over 50,000 mPa/sec. Typical amine equivalent weights are 100-150. The polyamidoamines react with bisphenol A epoxy resins at room temperature although the adhesives usually require several hours to reach sufficient molecular weight to carry a load. Cure times can be shortened to a few minutes at about 150°C. 

It is made by dimerizing cyanamide in basic aqueous solution, and is a colorless solid melting at 208°C. Dicyandiamide is soluble in polar solvents, but at room temperature is insoluble in bisphenol A epoxy resins. It can be made into a very fine powder and milled into epoxy resins to form stable dispersions. Because the dicy is insoluble in the epoxy, the only possible reaction sites are at the particle surfaces. Although some reaction certainly occurs over a short time, the adhesives easily can have a useful shelf life of six months. On heating to about 150°C, the dicyandiamide becomes soluble in the epoxy resin, and the adhesive polymerizes rapidly. Cure can be accelerated by incorporation of tertiary aromatic amines or substituted ureas. 

The difference between the amount of acid added and the amount unconsumed, determined by titration with a standard base, is converted to the epoxide equivalent (Lee and Nivelle, 1972). Complete procedures of determining the EEW are given elsewhere (Lee and Nivelle, 1967). The EEW is the most important characteristic of bisphenol A epoxy resin. 

Covers a two-part epoxy-resin system in the form of a bisphenol "A" epoxy resin filled with fumed silica and carbon microspheres and a separate aromatic diamine curing agent. 

The matrices were two DGEB A (diglycidyl ether of bisphenol A) epoxy resins. The hardeners were either 35 parts by weight of diamino diphenyl sulfone (resin I) or 55 parts of polyamino amide (resin II). The curing conditions were 3 h at 130°C followed by 3 h at 180°C for resin I and 24 h at 40°C followed by 6 h at 100°C for resin II. 

Most of the data reported here will be concerned with bisphenol A epoxy resin systems cured with the liquid anhydride, 1-methyltetrahydrophthalic anhydride (the Union Carbide commercial designation for this material is ZZLA-0334). However, these quaternary phosphonium compounds have also been shown to be effective with other anhydrides such as hexahydrophthalic anhydride (HHPA). 

The antioxidant system investigated is a synergistic syst composed of a phenol, namely, tetrakls[methylene 3-(3, 5 -di-t-butyl-4 -hydroxyphenyl)propionate]methane (Irgcmox 1010) and a sulfur compound, namely, dlstearylthiodipropionate (DSTDP), both added at 0.5 phr to the CPE. The dehydrochlorlnation stabilizers consisted of a bisphenol A epoxy resin (DER331) added at 4 phr concentration and PbO added at 5 phr concentration. The effects of these systems on the dehydrochlorlnation rates of peroxide crosslinked CPE and 2-roercaptoimidazoline crosslinked CPE are shown in Figure 2. 

This study demonstrated that the final destination of the added core-shell rubber particles, in PC, PA, or both, in the PC-PA binary blend can be controlled by properly selecting the chemical structure of the shell in the core-shell rubber. The unreactive MBS rubber tends to reside in the PC phase and near the vicinity of the PC-PA interface. The reactive MBS-MA rubber can have a chemical reaction with PA end groups and can therefore be retained within the PA phase. High-molecular-weight bisphenol A epoxy resin has proved to be an efficient compatibilizer for PC-PA blends. Rubber-toughening of the PC-PA blend in which PC is the matrix is much more effective than with blends in which PA is the matrix. 

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