Polyester preforms useful for enhanced heat-set bottles

A polyethylene terephthalate preform having an improved reheating profile, comprising:

• polyethylene terephthalate polymers including less than about 6 mole percent comonomer substitution;
• less than about 25 ppm of elemental antimony, if any;
• more than about 5 ppm of elemental phosphorus;
• and
• a heat-up rate additive that is present in an amount sufficient to improve the preform's reheating profile;
• wherein the polyethylene terephthalate preform has an intrinsic viscosity between about 0.68 and 0.86 dl/g;
• wherein the polyethylene terephthalate preform has a heating crystallization exotherm peak temperature (TCH) of more than about 140° C. at a heating rate of 10° C. per minute as measured by differential scanning calorimetry;
• wherein the polyethylene terephthalate preform has an absorbance (A) of at least about 0.25 cm−1 at a wavelength of 1100 nm or at a wavelength of 1280 nm;
• and
• wherein the polyethylene terephthalate preform has an L* value of more than about 75 as classified in the CIE L*a*b* color space.

A polyethylene terephthalate preform having low comonomer modification, comprising:

• polyethylene terephthalate polymers including less than about 5 mole percent comonomer substitution;
• between about 2 and 50 ppm of elemental titanium;
• less than about 100 ppm of elemental antimony, if any;
• and
• a heat-up rate additive that is present in an amount sufficient to improve the preform's reheating profile;
• wherein the polyethylene terephthalate preform has an intrinsic viscosity less than about 0.86 dl/g;
• wherein the polyethylene terephthalate preform has a heating crystallization exotherm peak temperature (TCH) of more than about 140° C. at a heating rate of 10° C. per minute as measured by differential scanning calorimetry;
• wherein the polyethylene terephthalate preform has an absorbance (A) of at least about 0.28 cm−1 at a wavelength of 1100 nm or at a wavelength of 1280 nm;
• and
• wherein the polyethylene terephthalate preform has an L* value of more than about 75 as classified in the CIE L*a*b* color space.

A polyethylene terephthalate preform, comprising:

• polyethylene terephthalate polymers including less than about 6 mole percent comonomer substitution;
• between about 5 and 15 ppm of elemental titanium;
• between about 15 and 40 ppm of elemental cobalt;
• less than about 25 ppm of elemental antimony, if any;
• less than about 5 ppm of elemental germanium, if any;
• and
• a heat-up rate additive that is present in an amount sufficient to improve the preform's reheating profile;
• wherein the polyethylene terephthalate preform has an absorbance (A) of at least about 0.20 cm−1 at a wavelength of 1100 nm and at a wavelength of 1280 nm;
• wherein the polyethylene terephthalate preform has a 1100:550 absorption ratio of at least about 70 percent, a 1280:550 absorption ratio of at least about 70 percent, a 1100:700 absorption ratio of at least about 85 percent, and a 1280:700 absorption ratio of at least about 85 percent;
• wherein the polyethylene terephthalate preform has an L* value of more than about 70 as classified in the CIE L*a*b* color space;
• and
• wherein the polyethylene terephthalate preform has a b* color value of less than about 4 as classified by the CIE L*a*b* color space.

A polyethylene terephthalate preform having excellent color, comprising:

• polyethylene terephthalate polymers including between about 2 and 5 mole percent comonomer substitution;
• between about 2 and 20 ppm of elemental titanium;
• between about 10 and 50 ppm of elemental cobalt;
• more than about 5 ppm of elemental phosphorus;
• less than about 25 ppm of elemental antimony, if any;
• less than about 5 ppm of elemental germanium, if any;
• and
• a heat-up rate additive that is present in an amount sufficient to improve the preform's reheating profile;
• wherein the polyethylene terephthalate preform has an intrinsic viscosity between about 0.72 and 0.84 dl/g;
• wherein the polyethylene terephthalate preform has an L* value of more than about 80 as classified in the CIE L*a*b* color space;
• and
• wherein the polyethylene terephthalate preform has a b* color value of between about −3 and 3 as classified by the CIE L*a*b* color space.