Types of epoxy resins

Bisphenol A (BPA) (Figure 14.1a) is a starting substance utilized in the manufacture of most types of epoxy resins, which are then crosslinked and used to coat food cans. Another application of BPA is in the manufacture of plastic materials, in particular polycarbonates. BPA serves also as an antioxidant or stabilizing material for many types of plastics, e.g., polyvinyl chloride (PVC). 

Resins used were two types of epoxy resins cured with anhydride and amine and iso-phthalic type polyester resin. 

Resins used were two types of epoxy resins (EP) and an unsaturated polyester resin (UP) as shown in Figure 1. EP is the bis-phenol-A type resin cured with methyl-tetrahydrophthalic anhydride (MTHPA) or 1,8-p-menthandiamine (MDA). UP is the iso-phthalic type resin which has ester bonds in the main chain and is crosslinked by styrene (10). 

Because of their excellent processing characteristics, especially for impregnating wound coils or fabrics, epoxy resins have been widely used for cryogenic temperature applications. There are many different types of epoxy resins available. 

Resin content Epoxy resin The bisphenol A type is most common. However, there are many other types of epoxy resins having differing properties. 

In addition to the DGEB A resins, there are several other types of epoxy resins of commercial significance. The most common of these are epoxy novolacs, glycidyl ether of tetraphe-nolethane, bisphenol F-based resins, and aliphatic and cycloaliphatic resins. 

Two types of epoxy resins are formed by this process (1) cycloaliphatic resins and (2) aliphatic resins. Of the many structures that can be synthesized by this process, the cycloaliphatic diepoxies offer the most interesting combination of properties. However, the aliphatic epoxy resins have the greatest utilization in epoxy adhesive formulation. 

The viscosity of an epoxy resin is dependent primarily on its molecular weight (MW). Low-MW resins typically have a viscosity in excess of 6000 cP, and conventional DGEBA epoxy resins (EEW = 190) have a viscosity around 12,000 cP. Therefore, for applications requiring relatively low viscosity, it is necessary to include other types of epoxy resin or to use diluents to achieve the desired properties. 

The type of epoxy group and its location within the molecule influence reactivity. Some epoxy resin structures prefer to react with acid curing agents, and others with basic curing agents. Certain epoxy structures are extremely reactive with specific catalysts, and others are virtually inactive. Several types of epoxy resins are reactive with almost all classes of curing agents. 

Many types of epoxy resins can be used in adhesive formulations. These are characterized in Table 4.1. The most commonly used type is the resin-based diglycidyl ether of bisphenol A (DGEB A). Epoxy novolac, flexible epoxy, high-functionality, and fihu-forming epoxy resins are also used in specialty applications. 

This chapter reviews the various types of epoxy resins and their characteristics in adhesive systems. These resins are classified by generic type as one of the following ... 

Epoxy resins based on diglycidyl ether of bisphenol A are not only the oldest type of epoxy resins but also the most valuable in adhesive formulations. The primary reasons for their popularity have been... 

In adhesive formulations, aliphatic amines are most commonly used to cure the DGEBA type of epoxy resin. Aliphatic amines are not widely used with the non-glycidyl ether resins, since the amine-epoxy reaction is slow at low temperatures. The reaction usually requires heat and accelerators for an acceptable rate of cure. Aliphatic amines are primarily used with lower-viscosity DGEBA resins because of the difficulty in mixing such low-viscosity curing agents with the more viscous epoxy resins. 

Epoxy adhesive formulations demand a great variety of solvents and diluents with a wide range of evaporation rates, solvent strengths, and dispersion powers. These variations are required due to (1) the many types of epoxy resins, curing agents, and possible organic additives that can be used within a formulation and (2) the many different possible methods that can be used to apply the epoxy to the substrate (brush, spray, trowel, etc.). 

The butadiene-acrylonitrile tougheners that have been especially successful in both DGEBA and DGEBF types of epoxy resins are... 

There are also many more types of epoxy resins and curing agents for more specialized applications. 

Like the testing variables just described, material variables can influence the fracture behavior of epoxy thermosets. Material variables discussed herein include the types of epoxy resins and amine curatives. 

There are three major types of epoxy resins cycloaliphatic epoxy resins (R and R are part of a six-membered ring), epoxidized oils (R and R are fragments of an unsaturated fatty acid, such as oleic acid in soybean oil), and glycidated resins (R is hydrogen and R can be a polyhydroxyphenol or a polybasic acid). The first two types of epoxy resins are obtained by the direct oxidation of the corresponding olefin with a peracid as illustrated by the following ... 

Recent developments indicate that new processes and raw materials will soon provide new types of epoxy resins. The most significant development is the epoxidation method using peracids as means of epoxidation. Per-acids are produced commercially either by the interaction of acids with hydrogen peroxide or by the oxidation of aldehydes. Peracids will epox-idize double bonds under controlled conditions, preferably in absence of water and free acids. It is anticipated that polyepoxides based on these processes will soon be available. 

The polyethylenes with higher functionality were soluble in epoxy resin and required lower temperamre and time for forming homogeneous blend systems. The miscibility of the polymers was dependent on the type of epoxy resin also. Cycloaliphatic epoxy resin showed more miscibility with the polymers compared to DGEBA resin and phase separation occurred in these blend systems as a result of crystallization of PE. Upper critical solution temperature (UCST) behavior was... 

Two different types of epoxy resins were added at different amounts. The resins were D.E.R. 331 , a liquid reaction product of epichlorohydrin and bisphenol A, and D.E.R. 351 , of epichlorohydrin with bisphenol A and bisphenol F (kindly supplied by Dow Chemical Company). 

The present study shows that the water resistance of MDF cements could be improved by the addition of two types of epoxy resins diglycidiyl ether of bisphenol A and a mixture of diglycidiyl ethers of bisphenol A and F. 

In order to install these devices, steel bolts are anchored in existing concrete pier/abutment by use of epoxy resin, as shown in Fig. 8. The minimum thickness of steel bracket is 22mm and the length of bore hole is 15 times more than diameter of anchoring rebar. Two types of epoxy resins, namely liquid resin and grease type resin, as shown in Table 1 are used for the anchoring. 

---