the amount of additives and or reinforcing filler and the rate of crystallization of the polyester component these examples are provided to illustrate the invention but are not intended to limit the scope of the invention the following materials were used in the examples of the present invention tpa based pet resin commercially available from sedapet catalana de polimers under the trade name pet br t dmt based pet resin commercially available from e i dupont de nemours u201c dupont u201d under the trade name pet crystar 3947 635 nucleating agent ethylene methacrylic acid ionomers commercially available from dupont as surlyn 8940 other additives in some examples sodium stearate is added as a nucleating agent in other examples ultratalc from specialty minerals inc is used irganox 1010 from ciba specialty chemicals is used as an anti oxidant pets or pentaerythrite tetrastearate from henkel kgaa is used as a mold release agent in all examples a werner amp pfleiderer zsk 25 supercompounder is used for melt blending the formulations with a targeted melt temperature of 280 u00b0 c the screw speed is set at 300 rpm and the throughput kg h of the extruder is adjusted in order to reach a torque level of 80 methods for determining the melting point and the degree of crystallinity are known in the art for example differential scanning calorimetry dsc density gradient tubes and x ray diffraction techniques for dsc analysis a sample to be analysed is heated up or cooled down together with a reference and the difference of heat flow to maintain both samples at the same temperature is monitored as a function of temperature or time crystallization and melting temperatures are recorded as the maximum of.