Polyhydantoin resins

Another amorphous terephthalate has also been introduced commercially. This is a copolymer based on 1,4-cyclohexylene glycol with a combination of terephthalic acid and isophthalic acid. The copolymer is claimed to have excellent optical properties, have low moulding shrinkage and be relatively easy to vaccum form. As with other terephthalates it is considered in more detail in Chapter 25. 

Available as wire enamels for some years, they also became available from Bayer as electrical insulating films in 1970. 

The resins are resistant to aqueous solutions of acids and alkalis and have a wide range of resistance to solvents. Amongst suitable solvents are methylene dichloride, dimethylformamide and phenol. The films bond well to poly-esterimide resins. 

Films have been used for insulating electric motors, in capacitors requiring a heat resistance not met by conventional polyester and polycarbonate dielectrics and as a soldering-resistant base for flexible printed circuits. 

Breakdown voltage (40p,m film/50Hz in air, ball/plate kV/mm 200 VDE 0303 Pt2 

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Uses For polyurethane industry for adhesives, binders, coatings, and sealants, molded elastomers, stmcturalfoam molding, appliances prod, of polyhydantoin resins, urethane-acrylate resins Trade Names Papi901... 

A coating composition consists of BPA/DC-BMI prepolymer, epoxide resin and Zn acetate in dimethylformamide a solution of polyhydantoin in CH2C12 is added [121]. 

Stenzenberger, in his papers [1,29] for toughening bismaleimide resins, cites the use of thermoplastics such as polyhydantoins [55] (Bayer s Resistofol N, Resistherm PH-10),... 

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