Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients

Definitions

• This invention relates to polymer compositions having improved melt strength which are useful for forming extrusion blow molded articles.
• the compositions contain a high molecular weight polyester such as polyethylene terephthaiate, a functional additive which has the ability of changing at least one physical property of the polyester but has the disadvantage of lowering the melt strength thereof, and a polycarbonate.
• High molecular weight PET homopolymer has sufficient melt strength for extrusion blow molding processes.
• certain functional additives in these polyesters to alter a physical property, such as incorporating pigment into the polyester to change its color.
• such functional additives have the adverse effect of degrading some of the physical properties such as melt strength.
• extrusion blow molding processes such as in the production of bottles, it is very desirable for the polymer to have good melt strength, because the extrudate must be self—supporting while in the melt for a period of time.
• PET polyethylene terephthalate
• CHDM 1,4—cyclohexanedimethanol
• a polymeric composition having improved melt strength comprising a) 90 to 99.5 wt % of a polyester containing repeat units from at least 90 mol % terephthalic acid and
• polyester having a weight average molecular weight of 75,000- 85,000, b) 0.05 to 9.9 wt % of a polymeric material containing 5-100 wt % polycarbonate and 0-95 wt % polyethylene terephthalate wherein the wt % of polymeric material is inversely proportional to polycarbonate level, and c) 0.005 to 6 wt % of a functional additive. wherein a), b) , and c) total 100 wt %.
• a polymeric concentrate which comprises a) 95 to 0 wt % of a polyester containing repeat units from at least 90 mol % terephthalic acid and 90 to 100 mol % ethylene glycol, said polyester having a weight average molecular weight of 40,000—85,000, b) 5 to 99.5 wt % of a polymeric material containing 90 to 100 wt % polycarbonate, and c) 0.5 to 60 wt % of a functional additive, wherein a), b) , and c) total 100 wt %.
• polyester specified in a) above is a high molecular weight polyester (i.e., 75,000—85,000)
• the polyester if used in b) is a carrier resin and may be of lower molecular weight (i.e., 40,000—85,000).
• PET which may be used in the blends of the present invention are well known and are available commercially. Methods for their preparation are described, for example, in U.S. Patent No. 2,465,319 and U.S. Patent No. 3,047,539.
• the dicarboxylic acid component may contain up to 10 mol % of other conventional aromatic, aliphatic or alicyclic dicarboxylic acids or polyfunctional anhydrides such as isophthalic acid, naphthalene— dicarboxylic acid, cyclohexanedicarboxylic acid, succinic acid, sebacic acid, adipic acid, glutaric acid, azelaic acid and the like.
• the glycol component may contain up to 10 mol % of other conventional aliphatic or alicyclic glycols such as diethylene glycol, triethylene glycol, ethylene glycol, propanediol, butanediol, pentanediol. hexanediol, 1,4—cyclohexanedimethanol and the like. 1,4—Cyclohexanedimethanol is preferred.
• Higher molecular weight PET i.e., weight average of 75,000—85,000 may be made by conventional methods such as melt phase polymerization followed by polymerization in the solid phase.
• I.V.s inherent viscosity representing these molecular weights are 0.9 to 1.1, preferably about 0.95.
• the PET may be modified up to 10 mol % with other conventional trifunctional or tetrafunctional glycols, acids, and anhydrides.
• Polycarbonate resins which are suitable for use in the present invention are well known in the art and are generally commercially available. These polycarbonates may be prepared by a variety of conventional and well known processes which include transesterification, melt polymerization, interfacial polymerization, etc.
• the polycarbonates are generally prepared by reacting a dihydric phenol with a carbonate precursor such as, for example, phosgene. Suitable processes for. preparing the polycarbonates of the present invention are described in, for example, U.S. Patent Nos. 4,018,750, 4,123,436 and 3,153,008. However, other known processes for producing polycarbonates are suitable.
• Particularly preferred polycarbonates are aromatic polycarbonates, prepared by reacting bisphenol—A [2,2—bis(4—hydroxy— phenyl)propane] with phosgene.
• compositions of the present invention may be subject to conventional processing methods such as injection molding, extrusion, etc.
• pellets of the PET, pellets of polycarbonate and the functional additive Prior to such processing, pellets of the PET, pellets of polycarbonate and the functional additive are mixed at the desired ratios.
• Specific industrial applications may require the addition of functional additives such as stabilizers, pigments, flame retardants, fillers, reinforcing agents, and/or processing aids.
• functional additives such as stabilizers, pigments, flame retardants, fillers, reinforcing agents, and/or processing aids.
• Other features of the invention will become apparent in the course of the following descriptions of exemplary embodiments which illustrate the invention and are not intended to be limiting thereof.
• the polyester used in the examples is poly(ethylene terephthalate) modified with 3.5 mol % 1,4—cyclohexane ⁇ dimethanol having an I.V. of 0.95, which is 80,000 weight average molecular weight.
• compositions of the following examples were extrusion blow molded into 18—ounce (510 g) wide mouth containers on a Bekum H—12IS extrusion blow molding machine equipped with an 80—mm high density polyethylene screw and a single head with a 0.70—inch (1.78 cm) ID die and a 0.675—inch (1.71 cm) OD mandrel. Melt strength improvements were evaluated by measuring the time and weight of an extruded parison from the extrusion blow molding machine to travel a distance of 24 inches (61 cm) below the die tip opening for a given die gap setting. The initial die gap setting, extruder screw speed and temperatures were established for a control sample and allowed to remain constant for all subsequent measurements on samples containing 3 wt % of the color concentrates.
• Example 2 (Control, PET and Functional Additive) —
• PET described above having a weight- average molecular weight between 75,000 and 85,000 was mixed with 3 wt % of a white color concentrate identify and having a weight—average molecular weight range of between 40,000 and 55,000, at the feed throat of the hopper on the extrusion blow molding machine with an additive feeder. After waiting 30 minutes to allow the system to equilibrate, average drop time for the molten parison to cover the same distance as described in
• Example 1 was 20 seconds and it weighed on the average 83 grams. The normalized results are 1,600 grams- seconds. In comparison with Example 1, these results are 14% lower than the control described in Example 1.
• Example 3 (According to Invention) — While continuing the extrusion of the extrusion blow moldable PET copolymer having a weight—average molecular weight between 75,000 and 85,000, a second white color concentrate prepared with 48.526 wt % of PET having a weight—average molecular weight of 40,000 to 55,000, 42.0 wt % TiO , 9.3 wt % of a polycarbonate and 0.174 wt % of a blue pigment and stabilizer was added with the additive feeder at 3 wt % of the total composition.
• the parison drop times and weights were measured again without changing the die gap and extruder speed settings that were established in Example 1.
• the average parison drop time was around 21 seconds.
• the average parison weight was about 89 grams.
• the normalized value was determined to be 1869.
• adding the small amount of polycarbonate to the white color concentrate brought the melt strength of the PET containing the white pigment within 3% of the neat PET.
• Example 4 While continuing to extrude the PET copolymer under the conditions given in Example 1, 3 wt % of a red concentrate prepared in a base poly(ethylene terephthalate) having weight—average molecular weight of 40,000 to 55,000 and containing 9.3 wt % polycarbonate was added from the additive feeder attached to the feed hopper.
• the red concentrate was melt mixed in a Werner— Pfleiderer ZSK twin screw extruder and consisted of 76.643 wt % poly(ethylene terephthalate) having weight— average molecular weight of 40,000 to 55,000, 9.3 wt % polycarbonate, 6.671 wt % Solvaperm (trademark) Red G R—88 dye, 6.526 wt % TiO pigment, 0.750 wt % Solvaperm Red BB R—91 dye and 0.110 wt % Solvaperm Blue B—51 due. After 30 minutes the parison weight and drop time were measured as described above. The parison drop time over the 24—inch (61 cm) distance was 21 seconds and the parison weight was determined to be 92 grams.
• Example 6 A black concentrate was prepared by melt compounding in a twin screw extruder a mixture of 70 wt % polycarbonate, 20 wt % Black Pigment BK 59 and 10 wt % a poly(ethylene terephthalate) copolyester modified with 3.5 mol % 1,4—cyclohexanedimethanol which had a weight—average molecular weight between 40,000 and 55,000.
• the concentrate was dried and added to the high molecular weight PET in the Bekum extrusion blow molding machine. Again, the average parison drop time and weight was determined without changing the conditions established in Example 1. The average parison drop time was surprisingly observed to be significantly long, 31 seconds and average parison weight much heavier, 128 grams.
• the normalized value was found to be 3,960 which is over two times greater than the normalized value for the control sample described in Example 1. Again, this clearly demonstrates that adding the polycarbonate to the color concentrates will surprisingly overcome the reduction in melt strength usually observed if the concentrates are prepared without the polycarbonate.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)

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• 1993
  • 1993-12-09 AU AU57429/94A patent/AU5742994A/en not_active Abandoned
  • 1993-12-09 WO PCT/US1993/011880 patent/WO1994014894A1/en not_active Application Discontinuation
  • 1993-12-09 EP EP94903511A patent/EP0675922A1/de not_active Withdrawn
  • 1993-12-30 CA CA 2151836 patent/CA2151836A1/en not_active Abandoned
• 1994
  • 1994-01-03 MX MX9400006A patent/MX9400006A/es unknown

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