Epoxide resins applications

Interesting developments were also taking place in the field of thermosetting resins. The melamine-formaldehyde materials appeared commercially in 1940 whilst soon afterwards in the United States the first contact resins were used. With these materials, the forerunners of today s polyester laminating resins, it was found possible to produce laminates without the need for application of external pressure. The first experiments in epoxide resins were also taking place during this period. 

NB Daia for the three important ihermosetting materials (phenolics, aminoplastics and epoxide resins) were not covered in the 1998 review on which the 1997 data was based. The 1987 figures for these materials do include a substantial percentage of use in adhesive, surface coating and laminate applications. 

Because of their favourable price, polyesters are preferred to epoxide and furane resins for general purpose laminates and account for at least 95% of the low-pressure laminates produced. The epoxide resins find specialised uses for chemical, electrical and heat-resistant applications and for optimum mechanical properties. The furane resins have a limited use in chemical plant. The use of high-pressure laminates from phenolic, aminoplastic and silicone resins is discussed elsewhere in this book. 

About half of epoxide resin production is used for surface coating applications, with the rest divided approximately equally between electronic applications (particularly for printed circuit boards and encapsulation), the building sector and miscellaneous uses. In tonnage terms consumption of epoxide-fibre laminates is only about one-tenth that of polyester laminates, but in terms of value it is much greater. 

For a number of purposes the unmodified epoxide resins may be considered to have certain disadvantages. These disadvantages include high viscosity, high cost and too great a rigidity for specific applications. The resins are therefore often modified by incorporation of diluents, fillers, and flexibilisers and sometimes, particularly for surface coating applications, blended with other resins. 

Epoxide resins reinforced with carbon and Aramid fibres have been used in small boats, where it is claimed that products of equal stiffness and more useable space may be produced with a 40% saving in weight over traditional polyester/ glass fibre composites. Aramid fibre-reinforced epoxide resins have been developed in the United States to replace steel helmets for military purposes. Printed circuit board bases also provide a substantial outlet for epoxide resins. One recent survey indicates that over one-quarter of epoxide resin production in Western Europe is used for this application. The laminates also find some use in chermical engineering plant and in tooling. 

The properties of the epoxide/cyanate compositions are inferior to those of non-modified cyanate polymers. They are, however, better in comparison with the properties of crosslinked BPA/ECH epoxide resin and epoxynovolaks [72]. Equimolar epoxide/cyanate ratio was recommended. Outstanding water resistance and dielectric properties at elevated temperatures are emphasized. In many patent applications, improved solvent resistance is mentioned. 

In several patents, the application of BPA/DC prepolymer in epoxide resin compositions is described [79, 81-84], This approach is similar of that mentioned in the chapter devoted to cyanate/maleimide compositions [62],... 

Epoxide resins can be crosslinked by polyaddition of active hydrogen-containing coumpounds, e.g. carboxylic acids, anhydrides (via intermediate ester-acid steps), amines, phenols, etc. or by polymerization via ionic mechanisms These reactions are generally started by application of heat. 

It was pointed out earlier that acid and anhydride containing polymers have many possible applications. With the exception of curing epoxide resins and examination of possible biological activity, little has been done to explore uses for the copolymers developed in this study. 

BS 3816, Cast Epoxide Resin Insulating Material for Electrical Applications at Power Frequencies, London (1964). 

Functionalized PPE can be used as thermosetting resins in combination with epoxide resins as powder coatings. Sealing resins for electric parts is another field of application." ... 

Epoxide resins are known for their toughness and chemical resistance properties. Because of this, they are widely used for composites in critical applications such as aircraft and aerospace, oil rigs, chemical storage tanks and high-speed boats, often in conjunction with carbon or aramid fibres. 

Electronics and electrotechnique are considered as promising areas of application of liquid-crystal polymers. In electronics, however, liquid-crystal polymers meet acute competition from cheaper epoxide resins and polysulfone. Another possible areas of using high-heat-resistant liquid crystal polymers are avia, space and military technique, fiber optics (cover of optical cable and so on), auto industry and film production. 

Several other types of curing agent are used with epoxide resins for laminating applications or in moulding compounds. Examples of these curing agents are ... 

For the purposes of this book, only those processes for which polyester resins and, to a limited extent, epoxide resins are used will be described. It should be noted, however, that the decorative laminates used in building and transport applications are in the main manufactured from melamine faced phenolic resin/paper laminates. 

Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an epoxide resin with polyamine hardener. Epoxy is used in coatings, adhesives and composite materials. They have excellent adhesion, chemical and heat resistance, good mechanical properties and electrical insulating properties. Epoxies with high thermal insulation, thermal conductivity combined with high electrical resistance are used for electronics applications. There are a few studies conducted on OPE-epoxy composites. 

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