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Fluid-assisted injection molding articles and processes for producing the articles are described. In one embodiment, a fluid-assisted injection molded article is formed from a polymeric composition containing a polyethylene terephthalate homopolymer in combination with a polyethylene terephthalate c

Fluid-assisted injection molding articles and processes for producing the articles are described. In one embodiment, a fluid-assisted injection molded article is formed from a polymeric composition containing a polyethylene terephthalate homopolymer in combination with a polyethylene terephthalate copolymer. The polyethylene terephthalate copolymer may comprise a copolymer of polyethylene terephthalate with isophthalic acid. The polymeric composition can also contain a reinforcing agent, such as glass fibers. Products made in accordance with the present disclosure have shown dramatically improved surface characteristics. In particular, pitting on the surface of the molded article is minimized.

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1. A molded product comprising: an injection molded article defining an exterior surface having a surface area and an internal fluid-formed hollow cavity, the article being made from a composition containing a polymer mixture and reinforcing fibers or reinforcing fillers, the polymer mixture compris

1. A molded product comprising: an injection molded article defining an exterior surface having a surface area and an internal fluid-formed hollow cavity, the article being made from a composition containing a polymer mixture and reinforcing fibers or reinforcing fillers, the polymer mixture comprising from about 45% to about 95% by weight of the composition, the polymer mixture comprising a polyethylene terephthalate homopolymer combined with a polyethylene terephthalate copolymer, the polyethylene terephthalate homopolymer and the polyethylene terephthalate copolymer being present in the polymer mixture in a weight ratio of from about 10:90 to about 70:30, the polymer mixture optionally containing another polyester polymer in an amount from 0% to about 25% by weight, the other polyester comprising a polybutylene terephthalate, a polybutylene naphthalate, a polytrimethylene terephthalate, a polypropylene terephthalate or a polycyclohexylene dimethyl terephthalate, the polymer mixture having a melt flow rate at 265° C. and at a 2160 g load of from about 20 g/10 min to about 50 g/10 min, the exterior surface of the article containing pits in an amount less than about 2.5% of the surface area of the exterior surface. 2. A molded product as defined in claim 1, wherein the polymer mixture only comprises the polyethylene terephthalate homopolymer and the polyethylene terephthalate copolymer. 3. A molded product as defined in claim 1, wherein the polyethylene terephthalate copolymer comprises a copolymer of polyethylene terephthalate with isophthalic acid, the isophthalic acid being present in the copolymer in an amount from about 0.5 mol % to about 10 mol % of the diacids. 4. A molded product as defined in claim 1, wherein the injection molded article further comprises a particulate filler. 5. A molded product as defined in claim 1, wherein the article contains reinforcing fibers comprising glass fibers, the fibers being present in the injection molded article in an amount from about 5% to about 50% by weight. 6. A molded product as defined in claim 1, wherein the polymer mixture contains polybutylene terephthalate in an amount from about 2% to about 15% by weight, the composition further comprising a pigment, the polybutylene terephthalate comprising a carrier for the pigment. 7. A molded product as defined in claim 1, wherein the polyethylene terephthalate copolymer comprises a copolymer of polyethylene terephthalate with isophthalic acid, the isophthalic acid being present in the copolymer in an amount from about 0.5 mol percent to about 10 mol percent, the article containing reinforcing fibers comprising glass fibers in an amount from about 5% to about 25% by weight. 8. A molded product as defined in claim 1, wherein the exterior surface of the article contains pits in an amount less than about 1.7% of the surface area of the exterior surface. 9. A molded product as defined in claim 1, wherein the injection molded article has a cylindrical-like shape. 10. A molded product as defined in claim 1, wherein the polymer mixture has an isothermal crystallization time at 220° C. of from about 0.7 mins to about 3 mins. 11. A molded product as defined in claim 1, wherein the composition used to form the injection molded article contains a stabilizer comprising a phosphite and a lubricant. 12. A molded product as defined in claim 1, wherein the injection molded article has an average wall thickness of less than about 0.25 inches. 13. A molded product as defined in claim 1, wherein the article contains reinforcing fibers comprising glass fibers, the fibers being present in the injection molded article in an amount from about 5% to about 25% by weight, the composition further containing a phosphite stabilizer, a lubricant, and talc particles, each of the lubricant, the talc particles, and the phosphite stabilizer being present in the composition in an amount less than about 2% by weight, the polyethylene terephthalate copolymer comprising a copolymer of polyethylene terephthalate with isophthalic acid, the isophthalic acid being present in the copolymer in an amount from about 0.5 mol percent to about 5 mol percent of the diacids. 14. A molded product comprising: an injection molded article defining an exterior surface having a surface area and an internal fluid-formed hollow cavity, the article being made from a composition containing a polymer mixture and reinforcing fibers or reinforcing fillers, the polymer mixture comprising from greater than about 60% to less than about 90% by weight of the composition, the polymer mixture comprising a polyethylene terephthalate homopolymer combined with a polyethylene terephthalate copolymer, the polyethylene terephthalate homopolymer and the polyethylene terephthalate copolymer being present in the polymer mixture in a weight ratio of from about 15:85 to about 65:35, the polymer mixture containing another polyester polymer in an amount from about 2% to about 15% by weight, the another polyester comprising a polybutylene terephthalate, a polybutylene naphthalate, a polytrimethylene terephthalate, or a polypropylene terephthalate, the polymer mixture having a melt flow rate at 265° C. and at a 2160 g load of from about 20 g/10 min to about 50 g/10 min, the reinforcing fibers or reinforcing fillers comprising from about 5% to about 25% by weight of the composition, the reinforcing fibers or reinforcing fillers comprising glass fibers, the exterior surface of the article containing pits in an amount less than about 2.5% of the surface area of the exterior surface.