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
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C49/00—Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
  • B29C49/02—Combined blow-moulding and manufacture of the preform or the parison
  • B29C49/04—Extrusion blow-moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B1/00—Layered products having a non-planar shape
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
  • C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/16—Dicarboxylic acids and dihydroxy compounds
  • C08G63/18—Dicarboxylic acids and dihydroxy compounds the acids or hydroxy compounds containing carbocyclic rings
  • C08G63/181—Acids containing aromatic rings
  • C08G63/183—Terephthalic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/78—Preparation processes
  • C08G63/80—Solid-state polycondensation
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/91—Polymers modified by chemical after-treatment
  • C08G63/914—Polymers modified by chemical after-treatment derived from polycarboxylic acids and polyhydroxy compounds
  • C08G63/916—Dicarboxylic acids and dihydroxy compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
  • Y10T428/1397—Single layer [continuous layer]

Definitions

• the present invention relates to co-polyester resin compositions and processes for manufacturing resin compositions, said resin compositions being suitable for extrusion blow molding for the manufacture of containers with good color, clarity for both food, non-food applications and other applications such as profile extrusions and manufacture of blown films which require high melt strength polyester.
• Extrusion blow molding is a well known manufacturing process used for producing hollow parts/bottles/containers from a plastic material.
• EBM process the polymer is melted and extruded into a hollow tube (a parison) and subsequently blow molded in containers of various sizes and shapes.
• the technology of machine and design as well as processing is quite advanced and matured.
• the polymers that are currently used in EBM application include polyethylene, polypropylene, SBC, and PETG.
• a polymer to be processed in a typical EBM application it must have the requisite melt strength.
• the polymer must also possess good stretch-ability in order to make a container of any design.
• color and clarity (transparency) are also important characteristics.
• PET polyester possesses many of the desirable properties that are required for design and development of wide variety of packaging materials which also include bottles and container for food grade and non food grade items.
• PET polyester is lighter in weight, unbreakable, transparent, recyclable and it also possesses high gas barrier properties.
• PET has been widely approved worldwide for packaging food grade items by many regulatory agencies. Because of all these reasons, there is a lot of market potential for PET polyester that is suitable for EBM application. In packaging applications colour and clarity (i.e. transparency) are also the most important desired characteristics.
• PET polyester as such can not be used for EBM application, on account of its low melt-strength.
• US Patent no. 4219527 discloses a process for blow molding a modified polyethylene terephthalate polymer.
• US Patent No. 4219527 is particularly silent over the use of chain extending agents for modifying the PET polymer. Furthermore, it is also silent as far as clarity, color and acetaldehyde content of the modified PET polymer is concerned.
• US Patent Application no 20080093777 discloses extrudable PET blends using chain extenders during extrusion process of EBM which employs a slow crystallizing polyester copolymer. Also, it is not possible to ensure proper uniform melt quality as the residence time in the extruders is very short to ensure uniform mixing without polymer degradations. One would also need blending equipments on every EBM machine.
• US Patent no 5523135 is based on mechanical blending of styrenic copolymer and glycidyl esters of unsaturated acids and vinylic co monomers. This is again a complicated blending process which not only seriously affects colour and clarity but also creates non uniform polymer quality and non uniform melt strength. Furthermore, the process as taught in US5523135 needs additional equipments.
• US 5,523,135 discloses a process for production of PET in which pre-polymerised PET with a high molecular weight is used in a blending or compounding step.
• US Patent no. 5523382 discloses process for producing polyester adapted to be extrusion blow molded into articles having improved rheological qualities, that employs 1,4- cyclohexanedimethanol for modifying the properties of the polyester.
• a process for preparation of an extrusion- blow-moldable co-polyester resin composition comprising the following steps : a. charging in a reactor at least one pair of polyester-forming materials selected from the group of pairs consisting of a 'diol-dicarboxylic acid' pair, a 'diol- dicarboxylic ester' pair and a diol-recycled PET pair, along with a co-monomer and optional at least one additive selected from the group consisting of an impact modifier, an antioxidant, a catalyst, an acetaldehyde inhibitor and a color toner, to obtain a reaction mixture;
• reaction mixture b. subjecting the reaction mixture to a method step selected from the group consisting of esterification, ester-interchange reaction and glycolysation yielding a pre-polymer;
• a chain extender in a proportion of about 0.05 wt. % to about 2.0 wt. %, preferably about 0.05 wt. % to about 0.8 wt. %, more preferably 0.05 wt % to 0.40 wt. % in the reaction mixture during step (b) in at least one portion or in continuous manner at controlled dosing rate when the intrinsic viscosity of the reaction mixture is ⁇ 0.20 , preferably ⁇ 0.10;
• Pre-polymer means a polyester formed in the reaction as long as its intrinsic viscosity is ⁇ 0.20.
• the diol is at least one selected from the group consisting of monoethylene glycol, diethylene glycol, triethylene glycol, butanediol, propanediol, and polyethylene glycols with a weight average molecular weight of up to 4000 g/mol, proportion of polyethylene glycol in said mixture being up to 5 % with respect to the mass of the total mixture.
• Monoethylene glycol is especially preferred.
• the 'diol-dicarboxylic acid' pair is used as the polyester-forming material.
• the di-carboxylic acid is at least one selected from the group consisting of purified terephthalic acid, isophthalic acid, adipic acid and sebacic acid.
• the di-carboxylic acid is purified terephthalic acid.
• the 'diol-dicarboxylic acid' pair is used as the polyester-forming material and wherein the esterification step b) is carried out at a temperature in the range of about 200 to 300 °C, preferably 220 to 280 °C and very preferably 240 to about 280 °C under the pressure up to about 4.5 bar for a period of about 1 to 10 hrs, preferably 1.5 to 6 hrs and very preferably 2.0 to 2.5 hrs.
• the molar ratio of the diol and the di-carboxylic acid in the diol-dicarboxylic acid pair is in the range of about 1.04 to about 1.45.
• the 'diol- dicarboxylic ester' pair is used as the polyester-forming material and wherein the dicarboxylic ester is dimethyl terephthalate.
• the molar ratio of diol and the dimethyl terephthalate in the 'diol- dicarboxylic ester' pair is in the range of about 2 to about 2.25.
• the dicarboxylic ester is dimethyl terephthalate and the ester-interchange reaction is carried out at a temperature in the range of about 140°C to about 270°C under absolute pressure of about 200 mbar to about 1200 mbar, preferably about 500 mbar to about 1100 mbar for a period of about 30 minutes to 3 hrs.
• the co-monomer is at least one selected from the group consisting of isophthalic acid, neopentyl glycol, pentaerythitol, glycerol, adipic acid, 2,6 Naphthalene Dicarboxylate (NDC), 2,6-Naphthalene dicarboxylic acid (NDA), dimethyl isophthalate Pentaerythritol and Glycerol.
• the 'diol- dicarboxylic ester' pair is used as the polyester-forming material and wherein the co-monomer is dimethyl isophthalate.
• the proportion of the co-monomer with respect to the mass of the reaction mixture is in the. range of about 4 to about 20 %, preferably about 6 to 15%, more preferably in the range of about 8 to 12%.
• the 'diol-recycled PET' pair is used as the polyester-forming material and wherein the glycolysation step is carried out at a temperature in the range of about 190 to about 260 °C under the pressure up to about 3.5 bar for a period of about 30 - 120 minutes, preferably 40 to 60 minutes yielding a pre-polymer.
• the catalyst is selected from the group consisting of poly-condensation catalyst and ester-interchange catalyst.
• the catalyst is at least one poly-condensation catalyst selected from the group consisting of Antimony compounds, Germanium compounds, Titanium compounds, Tin compounds and Aluminium compounds.
• the catalyst is at least one ester-interchange catalyst is selected from the group consisting of zinc acetate and manganese acetate.
• the color toner is at least one selected from the group consisting of cobalt acetate and polymer soluble dyes.
• the chain extender is at least one copolymer containing at least in average two epoxy groups / polymer chain and a number average molecular weight of the chain extender M n in the range from 1000 to 10000 Dalton.
• the chain extender is at least one copolymer having an epoxy equivalent weight in the range of 150 to 700.
• the chain extender is charged in the form of a pre-mix comprising the chain extender and a carrier selected from the group consisting of powdered PET and powdered Co-PET.
• the stabilizer is at least one aliphatic phosphate selected from the group consisting of carboxy ethyl dimethyl phosphate and phosphoric acid.
• the grade of the co-polyester resin is adjusted by varying the proportion of the chain extender that is added in the reaction mixture.
• the acetaldehyde (AA) content of the polyester resin is less than 10 ppm, preferably less than 5 ppm, very preferably less than 3 and especially preferably less than 1 ppm at the end of step e).
• the amorphous chips are crystallized in equipment selected from the group consisting of tumble dryer, rotary crystallizer and high rpm agitated reactor (solidaire).
• the method step (f) is carried out in a reactor selected from the group consisting of batch reactor and continuous reactor.
• the recycled PET is at least one selected from the group consisting of post consumer recycled PET and post industrial recycled PET.
• a process for preparation of co-polyester resin composition wherein the proportion of the chain extender is about 0.05 wt. % to about 2.0 wt. %, preferably about 0.05 wt. % to about 0.8%, more preferably 0.05 wt. % to 0.4 wt. % with respect to the mass of the reaction mixture and the EBM-grade co- polyester resin composition obtained has intrinsic viscosity in the range of about 0.80 to about 1.40 and is gel free and transparent.
• an extrusion-blow-moldable co-polyester resin composition with intrinsic viscosity in the range of about 0.70 to about 2.0 which includes a chain extender in the proportion of about 0.05% to about 2.0% with respect to the mass of the resin added before polymerization in at least one portion or in continuous manner at controlled dosing rate when the intrinsic viscosity of the reaction mixture is ⁇ 0.20 , preferably ⁇ 0.10.
• the chain extender may be added in at least two portions, preferably in at least three portions, very preferably in at least four portions, and especially in a continuous manner and at a controlled dosing rate.
• the portions may be of equal or different size, preferably of equal size.
• the melt strength of the co-polyester at a temperature of 260 °C to 275°C is in the range of about 0.05 N to 0.5 N, preferably 0.08 N to 0.25 N and the haul-off speed is in the range of about 20 m/min to 180 m/min, preferably about 60 m/min to 160 m/min.
• the extrusion-blow-moldable co-polyester resin composition is characterized by L* transmission value > 92.0 %, a* color value of between -1.0 ⁇ 0.5 and b* color value of between 0.3 ⁇ 0.5 as classified by the Hunter L*a*b* color space.
• an extrusion-blow- molded shaped article optionally having an integral hollow handle formed from the co-polyester resin composition of the present invention.
• the shaped article is at least one article selected from the group consisting of a parison, a container, a film and a tube.
• the volume of the shaped article is in the range of about 20ml to about 25 liters for food and nonfood applications
• the extrusion-blow- molded shaped article formed from the co-polyester resin composition is transparent.
• Fig 1 Graph showing Haul off force (N) vs. Haul off speed (m/min.) for EBM grade PET (Sample no. 11, 12, 13, 35 and 37), ISBM grade PET (PET CB602) and EBM grade PP (R520Y).
• Fig 2 Graph showing variation in shear viscosity (Pa.s) with variation in shear rate (1/s) for EBM grade PET (Sample no. 11, 12 and 13) and EBM grade PP (T300).
• Fig 4 Flow chart illustration of the process in accordance with the present invention which employs diol-dicarboxylic acid route
• Fig 5 Flow chart illustration of the process in accordance with the present invention which employs diol-dicarboxylic ester route.
• Fig 6 Flow chart illustration of the process in accordance with the present invention which employs the recycled PET feedstock as the starting material
• the known methods for manufacturing EBM grade polyester employ the compounding approach for incorporation of various additives along with the polyester wherein the chain extender is introduced in the polyester only after solid state polymerization when the intrinsic viscosity of the polyester is more than 0.55.
• the known process is illustrated by a flowchart in Figure 3.
• the known process suffers from a severe shortcoming, i.e formation of gel particles in the resultant polyester. This in turn also adversely affects the color and clarity of the final product.
• a process for preparation of an extrusion blow moldable co-polyester resin wherein a chain extending agent is incorporated during the formation of the co-polyester resin itself.
• the chain extending agent is introduced during the monomer formation & oligomer or pre-polymer formation in the reaction mixture, when the viscosity of the reaction mixture is very low, particularly below 0.2 and preferably less than 0.1.
• reaction mixture b. subjecting the reaction mixture to a method step selected from the group consisting of esterification, ester-interchange reaction and glycolysation yielding a pre-polymer;
• a chain extender in a proportion of about 0.05 wt. % to about 2.0 wt. %, preferably about 0.05 wt. % to about 0.8 wt. %, more preferably about 0.05 wt. % to 0.40 wt. %in the reaction mixture during step (b) in at least one portion or in continuous manner at controlled dosing rate when the intrinsic viscosity of the reaction mixture is ⁇ 0.20 , preferably ⁇ 0.10;
• a PET polymer is prepared by three different routes:
• the reaction mixture is subjected to esterification.
• the reaction mixture is subjected to the ester-interchange reaction.
• PET is employed from recycled PET, first it is glycol ized and then further processed.
• the different di-carboxylic acids that are used in the process of the present invention include purified terephthalic acid, isophthalic acid, adipic acid and sebacic acid.
• purified terephthalic acid is used as the dicarboxylic acid.
• the esterification step is carried out at a temperature in the range of about 200 to 300 °C, preferably 220 to 280 °C and very preferably 240 to about 280 °C under the pressure up to about 4.5 bar for a period of about 1 to 10 hrs, preferably 1.5 to 6 hrs and very preferably 2.0 to 2.5 hrs.
• the molar ratio of the diol and the di-carboxylic acid in the diol- dicarboxylic acid pair is in the range of about 1.04 to about 1.45.
• the catalyst typically used for the polycondensation method step include at least one polycondensation catalyst selected from the group consisting of Antimony compounds, Germanium compounds, Titanium compounds, Tin compounds and Aluminium compounds.
• the Sb content can be in the range up to 300 ppm , preferably below 260 ppm .
• the Ge content can be up to 150 ppm , preferably below 80 ppm .
• the Ti or Sn or Al content can be up to 200 ppm . It is always possible to use combination of these catalysts to get optimum results.
• the co-monomer is selected from the group consisting of isophthalic acid, neopentyl glycol, pentaerythritol, glycerol, adipic acid, 2,6 Naphthalene Dicarboxylate (NDC), 2,6-Naphthalene dicarboxylic acid (NDA).
• the polycondensation reaction is carried out at a temperature in the range of about 270 to about 305°C, preferably at 270 to about 290°C at a pressure of less than 10 mb, preferably below 2mb, more preferably below 1 mb
• a terephthalate ester is one of the polyester forming materials along with a diol.
• the molar ratio of diol and the dimethyl terephthalate ranges between 2 to about 2.25.
• the temperature at which the ester-interchange reaction is carried out ranges between 140°C to about 270°C for a period of about 30 minutes to 3 hrs and the reaction is carried out under absolute pressure of about 200 mbar to about 1200 mbar, preferably about 500 mbar to about 1 100 mbar.
• Zinc acetate and Manganese acetate either alone or in combination is used as the catalyst in the ester-interchange reaction.
• Dimethyl isophthalate is used as the co-monomer.
• the chain extender is added in the reactor during the time when the process of pre-polymer formation has just begun in the reaction mixture.
• it is incorporated in the reactor before the intrinsic viscosity of the reaction mixture reaches a pre-determined value.
• This pre-determined value is typically below 0.2, preferably below 0.1.
• the diol is at least one selected from the group consisting of monoethylene glycol, diethylene glycol, triethylene glycol, butanediol, propanediol, and polyethylene glycols with a weight average molecular weight of up to 4000 g/mol, proportion of polyethylene glycol in said mixture being up to 5 % with respect to the mass of the total mixture.
• the diol is monoethylene glycol.
• the proportion of the co-monomer with respect to the mass of the reaction mixture is in the range of about 4 to about 20 %, preferably about 6 to 15%, more preferably in the range of about 8 to 12%.
• chain extender means a hydrocarbon compound having at least two functional groups.
• a polymeric reactive chain extender used in accordance with the present invention is a copolymer of recurring units of an epoxy-functional (meth)acrylic acid derivative, a nonfunctional styrene derivative and/or a non functional (meth)acrylic acid derivative.
• the term (meth)acrylic acid derivative includes the free acid, esters and salts of acrylic acid and methacrylic acid.
• Typical esters are the methyl, ethyl, propyl, n-butyl, tert.-butyl, pentyl, 2- ethylhexyl or hexyl esters.
• Typical salts are the sodium, potassium, ammonium or zinc salts of the respective acid.
• epoxy-functional (meth)acrylic acid derivative embraces any epoxy-group containing derivative of acrylic and methacrylic acid. Typically these are epoxy-group containing esters of the respective acid, such as glycidyl acrylate and glycidyl methacrylate.
• a non functional styrene derivative is, for example, styrene, a-methylstyrene or dodecylstyrene.
• the copolymer is a copolymer of glycidyl(meth)acrylate, styrene, n-butylacrylate, 2- ethylhexylacrylate and methylmethacrylate with more than 5% by weight of glycidyl(meth)acrylate, based on the weight of the monomer mixture.
• the chain extender is at least one copolymer containing at least two, preferably at least three epoxy groups in average per polymer chain and a number average molecular weight M n in the range from 1000 to 10000 Dalton.
• the chain extender is at least one copolymer having an epoxy equivalent weight in the range of 150 to 700, preferably 180 to 400, and very preferably 200 to 320.
• the chain extender has an epoxy equivalent weight between 180 and about 2800, a weight average epoxy functionality value up to about 140 and a number average molecular weight Mn value of less than 10000 Dalton, preferably less than 6000 Dalton as defined in US 6,984694.
• copolymers are items of commerce and, for example available from BASF SE under the tradename "Joncryl”(RTM), in particular Joncryl ADR 4300, 4370, 4368, 4380 and 4385 or similar polymeric chain extender from BASF. These products, their preparation and general use are for example described in US 6,984,694.
• the chain extender is at least one selected from the group consisting of Joncryl ADR 4300, 4370, 4368, 4380, and 4385.
• the polyrrieric chain extender is Joncryl ADR 4368 with a weight average molecular weight Mw of 6800 and having an epoxy equivalent weight of 285 g/mol.
• chain extenders that may be used in the preparation of co-polyster resin composition of the present invention include bisoxazolines, phenylene-bis-oxazoline, Carbonyl bis (1-caprolactam), bis-anhydrides, diepoxide bisphenol A-glycidyl ether and the like.
• the chain extender is charged in the form of a pre-mix comprising the chain extender and a carrier selected from the group consisting of powdered PET and powdered Co-PET.
• the proportion of the chain extender is in the range of about 0.05 to 0.8% with respect to the mass of the reaction mixture.
• the stabilizer used in the process of the present invention is at least one aliphatic phosphate selected from the group consisting of carboxy ethyl dimethyl phosphate, and phosphoric acid.
• the color toner is at least one selected from the group consisting of cobalt acetate and polymer soluble dyes.
• cobalt acetate is used as a colorant.
• the impact modifier that is employed in accordance with the process of the present invention is at least one aliphatic higher chain diol selected from the group consisting of Polyethylene Glycol (PEG-400), Ethylene Acrylic Ester Maleic Anhydride / Glycidyl Methacrylate (Lotader), Ethylene Methyl / Butyl Acrylate ( Lotryl), Styrene Ethylene Butylene Block copolymer (Krayton).
• PEG-400 Polyethylene Glycol
• Litader Ethylene Acrylic Ester Maleic Anhydride / Glycidyl Methacrylate
• Lotryl Ethylene Methyl / Butyl Acrylate
• Styrene Ethylene Butylene Block copolymer Krayton
• the process in accordance with the present invention offers to achieve a cost performance balance for manufacturing different sizes and shapes of the container by preparing different grades of the co-polyester resin composition of the present invention. Different grades of the extrudable co-polyester resin composition are produced by varying the proportion of the chain extender that is added in the reaction mixture.
• the acetaldehyde (AA) content of the co-polyester resin prepared in accordance with the process of the present invention is less than lOppm, preferably less than 5 ppm, very preferably less than 3 and especially preferably less than 1 ppm at the end of step e).
• the amorphous chips are crystallized in equipment selected from the group consisting of tumble dryer, rotary crystallizer and high rpm agitated reactor (solidaire).
• the solid state polymerization is carried out in a reactor selected from the group consisting of batch reactor and continuous reactor.
• the comonomer typically is Isophthalic Acid (IPA)
• a chain extender in a proportion of about 0.05 wt. % to about 2.0 wt. %, preferably about 0.05 wt. % to about 0.8%, in the reaction mixture in at least one portion or in continuous manner at controlled dosing rate when the intrinsic viscosity of the reaction mixture is ⁇ 0.20 , preferably ⁇ 0.10;
• the recycled PET is at least one selected from the group consisting of post consumer recycled PET and post industrial recycled PET.
• All the additives employed in the process for preparation of an extrusion-blow-moldable Co-PET resin from the recycled PET feedstock in accordance with the present invention and the additives and their respective proportions as used in the process for a process for the preparation of an extrusion-blow-moldable co-polyester resin composition from polyester forming materials, are the same except that the later process does not employ Purified Terephthalic Acid (PTA) / Dimethyl Terephthalate (DMT) and Zinc acetate and manganese acetate (catalysts).
• PTA Purified Terephthalic Acid
• DMT Dimethyl Terephthalate
• Catalysts Zinc acetate and manganese acetate
• Fig 6 provides a Flow chart illustration of the process in accordance with the present invention which employs the recycled PET feedstock as the starting material
• a process for preparation of co-polyester resin composition wherein the proportion of the chain extender is about 0.05 wt. % to about 2.0 wt. %, preferably about 0.05 wt. % to about 0.8%, more preferably 0.05 wt. % to 0.4 wt. % with respect to the mass of the reaction mixture and the EBM-grade co- polyester resin composition obtained has intrinsic viscosity in the range of about 0.80 to about 1.40 and is gel free and transparent.
• an extrusion-blow-moldable co-polyester resin composition with intrinsic viscosity in the range of about 0.70 to about 2.0 which includes a chain extender in the proportion of about 0.05% to about 2.0% with respect to the mass of the resin added before polymerization in at least one portion or in continuous manner at controlled dosing rate when the intrinsic viscosity of the reaction mixture is ⁇ 0.20, preferably ⁇ 0.10.
• the melt strength of the co-polyester at a temperature of 260 °C to 275°C is in the range of about 0.05 N to 0.5 N, preferably 0.08 N to 0.25 N and the haul-off speed is in the range of about 20 m/min to 180 m/min, preferably about 60 m/min to 160 m/min.
• the extrusion-blow-moldable co-polyester resin composition is characterized by L* transmission value > 92.0 %, a* color value of between -1.0 ⁇ 0.5 and b* color value of between 0.3 ⁇ 0.5 as classified by the Hunter L*a*b* color space.
• an extrusion-blow- molded shaped article optionally having an integral hollow handle formed from the co-polyester resin composition of the present invention.
• the shaped article is at least one article selected from the group consisting of a parison, a container, a film and a tube.
• the volume of the shaped article is in the range of about 20ml to about 25 liters.
• the extrusion-blow- molded shaped article formed from the co-polyester resin composition is transparent.
• the shaped articles manufactured from the EBM grade co-polyester composition of the present invention are useful for packaging of various food and non-food articles.
• Provided herein below are the various characteristic properties of the extrusion-blow-moldable co-polyester resin composition of the present invention, prepared in accordance with the process of the present invention which employs the 'polyester-forming materials' as the starting materials, wherein the proportion of the chain extender is in the range of 0.1 to 0.4% .
• the characteristic properties of the shaped articles prepared from said composition are also provided in the last column of the table herein below.
• the polymer is dissolved in a mixture of Phenol/1.2 dichlorobenzene solvent whereupon the time of flow is determined in an Ubbelohde Viscosimeter.
• the relative viscosity is obtained from the quotient of the time of flow of the Polymer solution (t) and that of the pure solvent (to) as
• the relative viscosity is linked with the intrinsic viscosity via. Bill Meyer's equation.
• n intr — X + X
• the intrinsic viscosity is defined as the limiting value of the ratio of the natural logarithm of the relative solution viscosity to the concentration "C of the polymer in the solution for "C against
• ti mean time of flow of polymer solution in seconds
• t 2 mean time of flow of solvent in seconds
• the Factor F is available from the table with the value of relative viscosity.
• the Melt Flow index (MFI ) of a thermoplastics is the measured gravimetric flow rate of a sample melt extruded from a die of specified length and bore diameter under prescribed conditions of temperature and pressure.
• PRINCIPLE - The turbidity of a solution of the polyester in phenol and 1,2-Dichlorobenzene ( 0.5 % by wt.) is measured with laboratory Haze meter. The intensity of the scattered light is compared with Formazine standard solution.
• volumetric flask Make up the volume to the mark with non turbid water and mix gently swiveling the flask to and fro.
• the turbidity of this dilute standard solution is then 1000 NTU.
• Working Standard Solutions are needed for the calibration of Turbidity meter.
• the required working standards can be prepared from the dilute standard solution 1000 NTU according to the table below.
• the required working standards can be prepared from the dilute standard solution 4000 NTU according to the table below:
• NB In order to prevent the formation of air bubbles that may falsify measurements, it is important not to shake the flask but to swivel it gently to and fro.
• the instrument is calibrated initially according to the manual.
• NTU nephelometric turbidity unit
• the blank should be between 0.2 and 0.4 NTU
• NTU ( sample ) ⁇ NTU ( bv ) NTU ( Polyster )
• the tristimulus colour difference meter determines the colour of the sample using three photocells which are proceeded by a red, green and blue filter respectively.
• EVALUATION - Report Hunter L, a and b from the display of the monitor.
• the Tristimulus colour difference meter determines the colour of the sample as three photocells, which are proceeded by a red, green and blue filter respectively.
• the acetaldehyde is expelled from the PET by heating it in a closed vessel, whereupon it is Gas Chromatographically determined in the gas volume of the vessel according to the Head Space method of analysis.
• Carrier gas N2 50 ml/min
• Burning gas H2 45 ml /min
• Amplifier Damping 11 C (high)
• Density of polymer chips is measure with a floating method by comparison in a density gradient column with an inert and well- wetting liquid.
• Crystallinity can be calculated using density values for totally crystalline polyethylene Terephthalate and for totally amorphous Polyethylene Terephthalate from literature.
• connection V in i and 2 are almost identical.
• the molecular weight distribution of the polymeric chain extender is measured by Gel Permeation Chromatography (GPC ) sometime called Size Exclusion Chromatography.
• GPC Gel Permeation Chromatography
• the solvent for the polymeric chain extender is THF and the gpc columns are two polymer labs Plgel 10 ⁇ mixed bed 300 * 7,5 mm size exclusion columns plus a PLgel 10 ⁇ guard column, or an equivalent column by another supplier.
• the detection is done with a temperature controlled refractive index detector.
• the molecular weight calculation requires the use of uniform polystyrene standards with known molecular weight.
• the polystyrene polymers for calibration are standard solution of polystyrene provided by Polymer Labs. After calibration of the instrument, the GPC software will calculate the number average molecular weight and the weight average molecular weight of the sample.
• the number of epoxy groups per polymer chain and the epoxy equivalent weight of a chain extender can be calculated according to US 6.984,694.
• the chain extender BASF's Joncryl ADR 4368 S, 0.2 wt% was charged continuously at controlled dosing rate for gradual induction.
• the chain extender was mixed in PET Powder or CoPET powder with Isophthalic Acid content up to 15 wt % and dosed in to the reactor through a metering screw.
• Stabilizer H 3 P0 4 or Tetraethylenepentamine, 150 ppm
• polycondensation was carried out at temperature 286°C under pressure of less than 0.2 mb.
• the amorphous chips (I.V. of 0.630) (The melt viscosity was checked by Ubbelohde viscometer using a mixture of phenol/ 1,2-dichlorobenzene) were manufactured and subsequently processed in batch SSP. First crystallization was carried out at temperature range of 130 °C and then SSP was carried out at temperature range of 190 °C - 215 °C (Table 2) till the final I.V of 0.80 to 1.40 was achieved. Table 1 : Pilot Polymerization
• the color and clarity of the co-polyester resin composition prepared in accordance with the present invention are found to be as good as the best available bottle grade chips for ISBM application. Furthermore, the final polymer is found to be gel free.
• Example 2 The same procedure as used in Example 1 was used. Various trials were done in 50 kg batch size Pilot Plant with 0.10%, 0.20% & 0.30% addition of Polymeric Reactive Chain Extender, Joncryl ADR 4368 and ADR 4300. The Chain extender was added during esterification, during esterification and prepolymerization. The amorphous resin I.V was in the range 0.640 to 0.650. The resin was processed in batch SSP to get final required I.V of 1.10 to 1.20. The melt viscosity was checked by Ubbelohde viscometer (using a mixture, of phenol/ 1, 2 -dichlorobenzene) and also Melt Flow Viscosity (MFI) was checked to confirm the high melt strength.
• MFI Melt Flow Viscosity
• Monoethylene glycol (MEG) and dimethyl terephthalate (DMT) were charged in the reactor in quantities 33 kg and 46.6 kg respectively for the batch size of 51.2 kg.
• Dimethyl terephthalate used was in flake form.
• the heating rate was controlled to get 140°C temperature in the reactor.
• 140°C manganese acetate catalyst solution 23 gm in 500 ml ethylene glycol was added to the reactor.
• ester-interchange reaction was started with the methanol getting distilled through the packed column via the condenser.
• the column top temperature was maintained at 75°C to avoid loss of MEG.
• the product temperature controller set point was gradually and slowly increased from 140 °C to 230 °C in 150 min.
• the Joncryl® chain extender ADR 4368 was added in 3 equal parts.
• the total quantity of chain extender added was 0.04 kg.
• the ester-interchange reaction was carried out at atmospheric pressure. However, the reactor pressure remained at 50 to 80 mb due to methanol generation.
• the batch was terminated at I.V. 0.650.
• the amorphous chips were crystallized in tumble batch dryer at 140°C for 2 hrs and later I.V. was upgraded to 1.150 at a temperature of 225°C.
• the batch was transferred to poly condensation reactor.
• the polycondensation reactor was gradually evacuated to a pressure of 0.5 mb and reactor temperature was increased to 290°C.
• the polycondensation reaction was monitored based on reactor agitator power consumption and reaction was terminated to get I.V of 0.620.
• the polymer was extruded to amorphous chips.
• the amorphous PET chips were crystallized in batch SSP at temperature of 140°C and upgraded to final I.V of 1.20
• amorphous PET resin was manufactured using PTA & MEG as raw materials.
• Antimony Triacetate catalyst was added at 200 ppm antimony and Germanium dioxide catalyst was added at 40 ppm germanium.
• Cobalt acetate was added at 40 ppm cobalt as a colour tonner.
• the mole ratio of MEG to PTA was maintained at 1.125.
• the esterification reaction was carried out at a temperature of 250°C under 3.0 bar pressure for about 2.5 hrs, after completion of esterification reaction which was evident by completion generation of process water as a bi-product.
• Phosphorous Acid stabilizer was added 40 ppm Phosphorous and the batch was transferred to polymerization reactor where polycondensation was carried out at a temperature of 290°C under 0.2 mb pressure. The rate of polycondensation was monitored by increase in agitator power consumption and the batch was terminated at preset value of agitator power consumption to get desired intrinsic viscosity (I.V) of 0.650. Subsequently the batch was extruded to make amorphous granules of I.V 0.650.
• I.V intrinsic viscosity
• the amorphous resin produced thus was crystallized at a temperature of 130 °C in batch SSP unit (Tumble Dryer) and then the temperature was increased gradually to 220°C to facilitate solid state of polymerization under pressure of less than 0.5 mb. Samples were taken at regular interval and rate of SSP was monitored so as to get required I.V of 1.20 and at this I.V, the batch was cooled and vacuum was broken by introducing nitrogen and the final SSP product was taken. P arameters ⁇ I.V E L* a* b*
• Chain extender was compounded with amorphous CoPET chips comprising 8.5% IPA.
• the Chain extender (Joncryl ADR 4368) content was 0.3% to 0.5% in the final polymer. After compounding it was noticed that the color values deteriorated and there was neither significant increase in I.V nor significant reduction in MFI.
• bottles and containers formed from the co-polyester of the present invention possess high clarity and good gloss and the color values and the clarity of containers is at least as good as transparent containers of good color made from bottle grade PET by ISBM.
• the crystallized co-polyester resin in accordance with the present invention is ready for processing immediately after the drying process.
• the polymer chips can be dried by conventional hopper dryers at temperature 160 °C - 175 °C using dehumidified air. There is no need of blending or compounding at the bottle manufacturer's end.
• the co-polyester resin composition in accordance with the present invention offers the advantage of faster processing on account of faster reaction rates in both melt phase polymerization and Solid State Polymerization.
• the co-polyester resin composition of the present invention is suitable for EBM application for manufacturing of hollow containers, parisons of very good colour and clarity in various designs, shapes and volumes with or without inbuilt handle.

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