Suppliers epoxy resins

Commercial epoxy adhesives are composed primarily of an epoxy resin and a curing agent. Various additives and modifiers are added to the formulation to provide specific properties. Example trade names and suppliers of these ingredients are included in App. A. The curing agent may be incorporated into the resin to provide a single-component adhesive, or else it may be provided in a separate container to be mixed into the resin immediately prior to application. 

Properties of several commercially available DGEBA epoxy resins from various suppliers are listed in App. C. Generally they can be divided into the following classifications ... 

The introduction of the novolac epoxy corrected the Tg problem and partially corrected the moisture resistance problem. Advances in the novolac epoxy technology have continued to improve the moisture resistance, as noted earlier in Figures 2 and 3. Corrosion due to chloride impurities, however, continued to be a very severe problem until the introduction of low chloride resins and hardeners by the Japanese resin suppliers. Figure 4 (Bates, Vm., Horton-Thiokol,... 

Polyamides. Polyamides are formed by the condensation reaction of polyamines with dimeric fatty acids. They are available from a number of suppliers in a large variety of viscosities and molecular weights. Many products are available in the form of adducts which provide good compatibility with epoxy resins without the need for an induction period and give a better cure under adverse conditions compared with standard polyamides. Polyamide curing agents offer a number of desirable features, as follows (Dow Chemical Company, undated b) ... 

Although DGEBA resins provide the backbone of most epoxy formulations, they may be blended with other types to achieve modifications. Epoxy novolacs, having higher functionality, increase the cross-linking density, which improves heat resistance but decreases impact resistance. Incorporation of epoxidized oils increases flexibility at the expense of heat and chemical resistance. Low-viscosity polyfunctional epoxies based on polyols or polyhydric phenols reduce viscosity and can increase functionality without impairing cured properties. Monofunctional reactive diluents will also decrease viscosity and form part of the polymer backbone, to impart a measure of flexibility without the possibility of migration. Properties of commercially available epoxy resins and diluents from various suppliers are listed in Table 1. 

Suppliers of a given type of plastics, such as polyethersulfones or epoxy resins, usually offer a whole range of grades. It is impossible to tell from company literature whether two resin grades are fundamentally different, or similar in all respects but for one detail, such as their ease of processing. 

Epoxy Resin Type Examples Resin/ Supplier Kinematic Viscosity (poise 25°C, unless indicated) Epoxy Equivalent Weight (gm)... 

The chemistry of this subject is complex and with the variety of epoxy resins and curing agents the reader is referred to references 3.3, 3.4 and 3.5 and should consult with materials suppliers for more detail. 

There are many suppliers of epoxy resin and they market equivalent grades One such example is the standard DGEBA resin, supplied by Ciba Specialty Chemicals Araldite MY750 (6010 in the USA), Dow DER 331 and Shell Epikote 828 (Epon 828 in the USA). 

Many other chemicals have become more expensive because of increases in the price of upstream intermediates. Tin stabilisers are affected by the rising price of tin metal and epoxy derivatives are also affected, with basic epoxy resins going up by about 200 euros/tonne in Eiuope in mid-2004. Some phenohc derivatives have also risen dramatically in price. A snapshot over two or three months diuing mid-2004 shows substantial price increases being announced by leading suppliers for impact modifiers, waxes, silica, phosphorus flame retardants and, as indicated earlier, brominated types. Plasticiser producers were also attempting price increases for DINP and DEHP. 

Major suppliers of epoxy resins include Akzo Nobel Chemical Inc. Ciba Specialty Chemicals Cytec Fiberite Inc. Dow Plastics Epic Resins Magnolia Plastics Inc. Resyn Corp. Shell Chemicals Thermoset Plastics, Inc. Union Carbide Corp. and United Resin Corp. 

S-glass composites are used in the majority of aerospace applications. The glass is used to the greatest extent in combination with epoxy resins. The resultant composite maintains excellent structural characteristics up to the degradation of the epoxy resin. A primary supplier of S-glass fiber is Owens Coming. 

In the late 1940s, two US. companies. Shell Chemical Co. and Union Carbide Corp. (then Bakelite Co.), began research on bisphenol A based epoxy resins. At that time, Shell was the only supplier of epichlorohydrin, and Bakelite was a leading supplier of phenolic resins and bisphenol A. In 1955, the four US. epoxy resin manufacturers entered into a cross-licensing agreement. Subsequently, The Dow Chemical Co. and Reichhold Chemicals, Inc. joined the patent pool and began manufacturing epoxy resins. 

Recently, there have been debates in the can coatings industry concerning the potential health effects of residual bisphenol A and DGEBA in epoxy can coatings. The resin suppliers, can coatings producers, and can makers have jointly formed an industry group to coordinate a number of studies on this issue. Results... 

In the late 1940 s, Shell Chemical Company, the only supplier of epichlorohydrin at that time, and Union Carbide (then Bakelite) entered into the field of epoxy resins. 

In formulating epoxy resin via-fill ink, one must consider the adhesion between the fill material and the copper plating in the hole barrel. Normally it may seem suitable to use a material that does not include an acrylic component. However, some supphers have found it more beneficial to add an acryhc component because of its resistance to moisture absorption. They determined that it would be preferable to improve the ink s adhesion to copper by pretreatment with a black oxide or chemical etching process.This is similar to the approach taken by many dielectric suppliers. 

These include the catalyst or a hardner and possibly an initiator or accelerator. They are not listed in this data set unless they form an important part of the resin s composition such as may occur with epoxy resins. Otherwise it is assumed that the moulder will use the appropriate type and quantity, in accordance with the supplier s instructions. In addition, it is assumed that the composite is fully cured this might well involve applying a temperature cycle after curing (section 12.3). 

Both the polystyrene and the epoxy resin were obtained from commercial suppliers in the pre-foamed condition. The foam material resulting from the manufacturing process has closed cells in the case of the polystyrene, but the epoxy foam is porous. These structures result in somewhat different thermal performance for the two types of material as found previously by Schrodt et al. ... 

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