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Thermoplastic copolyesters prepared from aromatic dicarboxylic acid substituted succinic acid or anhydride and a glycol and the use thereof in adhesives. A thermoplastic copolyester is formed of at least one aromatic dicarboxylic acid member, at least one aliphatic dicarboxylic acid member (an alkyl- or alkenyl-substituted succinic acid(cas:110-15-6) or anhydride thereof), and at least one C2 -C10 glycol. Particularly preferred copolyesters are those wherein at least one non-polymeric polyfunctional member is added to the base copolyester composition to function as a chain-extender therefor. The resultant copolyester is useful as an adhesive both by itself and as an ingredient of hot melt or solution adhesive formulations.
EXAMPLE I
This example illustrates preparation of the thermoplastic copolyesters of the present invention.
Stage I. In a 2-liter, round-bottom pyrex flask equipped with stainless steel stirrer, thermometer, nitrogen inlet, 18 inch Vigreux column, 20 ml distillation receiver and condenser, there were introduced 388.0 parts dimethyl terephthalate, 401.2 parts 1,6-hexanediol, 0.50 parts dibutyltin oxide, 0.20 parts antimony trioxide and 0.40 parts 4,4'-thiobis-(6-tertiary butyl meta cresol). Reactions were heated with stirring to 136-230° C. for 2.5 hours until 125.6 parts methanol was distilled off and discarded.
Stage II. 210.0 Parts octenyl succinic acid(cas:110-15-6) anhydride and 86.0 parts xylene were introduced into the reacton and heated with stirring for 3 hours under reflux at 188°-211° C. until 40 parts water were distilled off and acid number equaled 0.33.
Stage III. The water of esterification and xylene in the distillation receiver were discarded. The Vigreux column was removed and the copolyester prepolymer was then poly-condensed under reduced pressure of 0.5-20 mm Hg and temperature of 255°-265° C. for 4.0 hours until a highly viscous product was obtained and discharged onto silicone release paper. On standing overnight (at room temperature) the product crystallized into a gray nontacky solid and had the following properties.
I.v. dl/g = 0.55
Tg° C. = - 37
Tm° C. = + 45, + 88
In this example, as well as those which follow, the I.V. (Intrinsic Viscosity) was determined using 0.5, 1.0 and 1.5% solution in 60/40 phenol 1,1,2,2-tetrachloroethane solvent and extrapolating to 0 concentration on a nsp/C vs concentration plot according to known methods. The values for Tg and Tm were determined on a DuPont model 900 Differential Thermal Analyzer.
EXAMPLE II
This example illustrates the use fo copolyesters of the present invention as solution adhesives. 30 Parts of the product from example I were dissolved in 90 parts 50:50 methylene chloride:toluene to which 6.0 parts of Trancoa 375B (75% in ethyl acetate solvent), a polyisocyanate from Trancoa Chemical Co., were added. The mixture was deposited on a 1 mil thick film of Mylar by means of a stainless steel wire wound rod to provide 3 mils (dry) thick film. After removal of the solvent by evaporation the coated Mylar specimens were laminated to 1 mil aluminum foil and aged overnight at room temprature R.T. The specimens were tested for initial and aged (one week at room temperature) peel or bond strength. Results were as follows:
Initial = 230 g./linear inch
Aged = 400 g./linear inch
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