Polyester imide enamels

Polyester Imide Enamels. The chemistry of the polyester Imide enamels differs from that of the polyesters in that methylene dianiline is one of the basic building blocks. Reaction with anhydrides such as trimellitic anhydride provides for the imide content, and the remaining acid group of the trimellitic anhydride is available to form ester linkages. 

Polyamide Imide Enamels. Aromatic polyamide imide insulations are made from aromatic acids and aromatic diamines. The polyamide imide polymers are primarily present in the form of polyamic acids in the Af-methyIpyrrolidone solutions. During the enameling process the polyamic acids undergo imidization and become essentially fully imidized. Whereas the polyester and polyester imide enamels contain cresylic acids as the major solvent, the polyamide imide enamels are mainly formulated with A/-methylpyrrolidone as solvent. 

Wire enameled with polyester imides can be used for applications in which it is occasionally exposed to temperatures in the 155-180 C range. One of the most demanding environments is in hermetic motors used in refrigerators where the insulating enamel film is exposed at elevated temperatures to oil and refrigerants under pressure. 

Isomid . [Schenectady] Polyester-imides wire enamels. 

Table 1 shows the average properties of commercial wire enamels, glycerine and THEIC branched polyesters (PE) and glycerine and THEIC branched po-ly(ester-imide)s (PEI). 

Work on improving the thermal resistance and particularly the resistance to carbonization (short circuiting of layers of enameled wires under the influence of temperature) via special glycols led to diphenols [29,30]. Diphenols are not reactive under the conditions of a normal poly(ester-imide) synthesis. In synthesis the lower aliphatic diesters of diphenols were used [29-32]. The use of acid chlorides in the polyester reaction with aromatic OH-groups was also protected by patents [33-35] but it seems unlikely that this reaction was performed on the production scale. 

Polyesters modified with diimidodicarboxylic acids derived from aliphatic diamines and trimellitic anhydride have been patented, like methylene-N,N-bis-trimellitimide, made from hexamethylenetriamine [82], or the 1,4-dimeth-ylaminocyclohexane derivative [83]. The diacid obtained from trimellitimide, made from the anhydride and dry ammonia, complexed with a divalent metal, e.g., Zn, Co and others, is used in the preparation of a poly(ester-imide), described as giving a wire enamel with good flexibility on copper wire [84]. 

The experience that the manufacturing equipment is less stressed when the polyester is formed first, and the availability of cheap polyfethylene terephtha-late) scrap, led to patents where all kind of processes were claimed to make po-ly(ester-imide) wire enamels from this polyester [97-101]. The problem is that clean, unpigmented and granulated poly(ethylene terephthalate) is needed for profitable production. There are some indications that this process is used today for industrial productions of wire enamels. Polyethylene terephthalate) is not only used as a raw material for the synthesis, but it can also be blended with a poly(ester-imide) to give a useful wire enamel [102]. 

Poly(ester-imide) resins have excellent thermal and mechanical properties, and wire enamels made from them are used in stressed electrical appliances. Other uses for imide modified polyesters are also known, where a balance between two thermal properties, cut through and soldering temperature, is required, e.g., in solderable poly(ester-imide)s and poly(ester-imide)s used in polyurethane wire enamels. A third application is in selfbonding wire enamels, where a softening of the film in a given temperature range is desired. 

Dual Constructions. In addition to the "basic" magnet wire insulations in which the conductor wire is coated with a single enamel, there are a number of cases where two different enamels are used one overcoated over the other. Examples include polyurethane-base insulation overcoated with poly(vinyl butyral) or with nylon, or polyester-base insulation overcoated with nylon or with polyamide imide. 

Uses Antimicrobial in cosmetics intermediate for epoxies, urethane resins, and antistatic lubricants for the textiles and plastics crosslinking agent for high-temp, resist, polyester or imide-amide wire enamels, acrylic, PU spec, coatings lubricant film-former Trade Names Dantocol DHE... 

Uses Antimicrobial in cosmetics intermediate for epoxies, urethane resins, and antistatic lubricants for the textiles and plastics crosslinking agent for high-temp, resist, polyester or imide-amide wire enamels, acrylic, PU spec, coatings lubricant film-former DEDM hydantoin dilaurate Synonyms Diethylol dimethyl hydantoin dilaurate Di-(2-hydroxyethyl) dimethylhydantoin dilaurate Di-(2-hydroxyethyl)-5,5-dimethyl hydantoin dilaurate 2,4-lmidazolidinedione, 1,3-bis (2-decanoyloxyethyl)-5,5-dimethyl-Definition Diester of DEDM hydantoin Empirical C29H60N2O6 Properties M.w. 532.80... 

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