Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • 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
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/15—Heterocyclic compounds having oxygen in the ring
  • C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
  • C08K5/1535—Five-membered rings
  • C08K5/1539—Cyclic anhydrides
• • 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
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
  • C08K7/04—Fibres or whiskers inorganic
  • C08K7/14—Glass
• • 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
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
• • 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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
  • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

Definitions

• the present invention relates to a new process for the pre ⁇ paration of articles formed of polyester resins endowed of valuable mechanical and impact strength properties.
• the polyester resins because of their favourable mechanical properties find wide application in the preparation of fi ⁇ bres and films.
• the resins utilized for this application ha ⁇ ve values of intrinsic viscosity generally between 0.6 and 0.8 dl/g.
• the resins are also used in blow-molding or extrusion- molding processes for the production of bottles and similar thin walled containers.
• the resins used in blow molding processes have a sufficien ⁇ tly high intrinsic viscosity to allow the realization of the injection operation.
• the viscosity suitable for these applications is generally between 0.7-0.8 dl/g and is obtained by solid state upgra ⁇ ding treatments.
• the invention process comprises a first phase in which the melt polyester resin mixed with an upgrading polyfunctional compound capable to increase the molecular weight of the re ⁇ sin by addition reactions in the solid state with the resin end groups is melt-shaped under temperature and duration conditions and at concentrations of the upgrading compound such as to avoid increasing the intrinsic viscosity to va ⁇ lues greater than about 1.0 dl/g and a second phase in which the formed article is subjected to upgrading reaction in the solid state so as to increase the intrinsic viscosity of at least 0.1 dl/g with respect to the polymer viscosity before the upgrading treatment.
• the resin used in the melt-shaping step has an intrinsic vi ⁇ scosity higher than 0.4 dl/g but generally lower than 1.0 dl/g.
• the polymer intrinsic viscosity in the manufactured article has values higher than about 0.7 dl/g and generally included between 0.7 and 1.8 dl/g.
• the polymer in the for ⁇ med articles having the above values of intrinsic viscosi ⁇ ty, shows particularly high mechanical properties such as the tensile strength and resiliency, higher than those of the polymer upgraded with processes different from that of the invention.
• the invention process is particularly suitable for the pre ⁇ paration of formed articles such as films, panels, plates sheets and generally thick-walled articles.
• a thermal treatment carried out on the formed article at tem ⁇ peratures higher than about 130°C and lower than the melting point of the resin.
• the treatment duration, the temperature and the concentra ⁇ tion of the upgrading additive are selected so as to obtain an increase of intrinsic viscosity of at least 0,1 dl/g in comparison with the intrinsic viscosity of the starting po ⁇ lymer used in the melt-shaping step.
• the upgrading reaction is carried out in inert gas stream, such as nitrogen, carbon dioxide or, if necessary,under vacuum.
• the mechanical properties are conside ⁇ rably improved if the upgrading treatment is carried under stretch.
• the utilizable stretching ratios are generally in ⁇ cluded between 1:2 and 1:8.
• the polyester resins used in the invention process include products of polycondensation of aromatic bicarboxylic acids such as terephthalic acid or its esters such as di ethylte- rep h thalate, naphthalenbicarboxylic acids, 5-ter butyl-1,3- benzendicarboxylic acids with glycol ⁇ with 2-10 carbon atoms such asethylene glycol, 1.4-cyclohexanediol, -4 butanediol, hydroguinone.
• Polyconden ⁇ ation products are also comprised containing, be ⁇ sides the units deriving from terephthalic acid or its esters, also up to 25% of all acid units, units deriving from bicarboxylic acids such as isophtalic and orthophtalic acid.
• Polyethyleneterephthalate and polybutyleneterephthalate are the preferred resins.
• the polyester resin can be added with other compatible poly ⁇ mers such as polycarbonates, elastomeric polyesters and po- lycaprolactone in amounts up to 20% by weight. .Recycled po ⁇ lyester can be used.
• the upgrading additives usable in the invention process lead - to the increase of the resin molecular weight by addition reactions in the solid state, with the end groups of the po ⁇ lyester resin.
• the additives are used in amount from about 0.05 to 2% by weight on the resin.
• the dianhydrides of the tetracarboxylic aromatic acids are the preferred additives.
• the dianhydride of pyromellitic acid is the preferred compound.
• Other representative dianhydrides are those of 3.3', 4.4'- benzophenone - tetracarboxy and, . 2,2 - bis (3,4 dicarboxylphenyl) propane acid, 3.3'-4.4'- biphenyltetracarboxy acid, bis (3.4 dicarboxyphenyl) propa- ne acid 3.3'- 4.4'- biphenyltetracarboxy acid, bis (3,4 di ⁇ carboxyphenyl) ether, bis (3,4 dicarboxyphenyl) sulfone and their mixtures.
• Dianydrides of aliphatic tetracarboxylic acids are also sui ⁇ table. Examples of these dianydrides are the dianydride of 1,2,3,4 cyclobutanetetracarboxylic acid and 2,3,4,5 tetra- carboxyhydrofuran acid.
• the blending of the resin with the additive is preferably carried out in a mono or twin screw extruder at a temperatu ⁇ re between 200° and 350°C.
• a counter rotating not intermishing twin screw extruder is preferred.
• the extruded polymer is subsequently pelletized and subjec ⁇ ted to the shaping process.
• the resin is melt-shaped according to the techniques inclu ⁇ ding extrusion blow molding, blow molding, injection- extrusion, extrusion to form sheets, tubes.
• additives can be blended in the polyester.
• additives include stabilizers, antioxidants, plasticizers pigments, nucleant agents, antiflame compounds, inert or reinforcing fillers such as glass fibers.
• the addition of the glass fibers improves the notched impact strength, initial flexural modulus and brea ⁇ king stress of the articles obtained with the invention pro ⁇ cess.
• the use of as a little as 5% by weight of glass fibers is sufficient to increase the properties. Concentrations as high as 60% or higher can be used.Preferred concentrations are from 10 and 40% by weight.
• the glass fibers are preferably 0.2 to 1 mm in length. They are added to the composition in any suitable manner. For example they may be incorporated into the polyester re ⁇ sin before the upgrading compound is added or the molten re ⁇ sin, the glass fibers and the upgrading compound are mixed in an extruder. Preferably the glass fibres are added to the polyester resin premixed with melt with the upgrading com- pound.
• the residence time of the resin in the shaping appa ⁇ ratus is lower than 2 minutes, preferably comprised between 20 and 100 seconds and the barrel temperature is lower than about 300°C and higher than the melting point of the resin.
• PET is the preferred resin for preparing glass fibers rein ⁇ forced articles.
• the glass reinforced resins are particu ⁇ larly suitable for preparing food containers for dual ovena- ble applications or for any other application involving heat treatment.
• Polybutylenterephtalate having an intrinsic viscosity of 0. 587 dl/g added respectively with 0 , 3% and 0 , 5% by weight of pyromellitic dianhydride (PMDA) (respectively polymer A and polymer B) is extruded in a counter rotating twin screw extruder Haake Rheocord 90 Fison to obtain chips with a di- mater o f about 3 mm and a length of 5 mm.
• PMDA pyromellitic dianhydride
• the intrinsic viscosity after extrusion was:
• Polymer A IV 0.599 dl/g
• Polymer B IV 0.616 dl/g
• the chips were then extruded in a mono screw extruder with filming head to mold a film with thickness of about 0.37 mm that is then subjected to an upgrading thermal treatment at
• the polymer intrinsic viscosity in the three different films after upgrading was:
• the intrinsic viscosity was determined in a solution at 60/40 by weight of phenol and tetraclorethane, operating at 25°C.
• Die type round with 3mm diameter 5Kg/h of the so obtained chips were fed into a mono screw extruder provided with a flat die suitable for cast film production.
• Head temperature 275°C Samples of 40 mm length were cut from the so obtained film and tested with anINSTRON tensile Tester (Mod. 4505) having a heating chamber.
• the samples were stretched with a rate of 1 mm/min so as to obtain a len ⁇ gthening of twice the original length.
• the obtained samples (not less than 5) were then subjected to the measuring of the tensile properties (elastic modulus, stress at break and at peak) .
• the elastic modulus values expected for films obtained from mixtures according to example 4 and comparative 1, in the hypothesis of perfect adhesion between LCP and the polyester matrix, are respectively of 2770 and 1790 MPa.
• PET polyethylene terephthalate
• a stran d pelletizer is used to obtain granules with a cylin ⁇ der shape having 3 mm as diameter and 5 mm as length.
• the intrinsic viscosity of the granules is 0.64-0.65 dl/g. 10 Kg/h of these granules are fed, after drying in a counterrota ⁇ ting twin screw extruder, 70 mm in diameter. L/D ratio equal to 32.
• the requested amount of glass fibres was fed by a lateral feeder.
• the re ⁇ maining 20 L/D length of the extruder was used to mix PET and glass fibres.
• Residence time in the extruder was 60-90 seconds at 270°C.
• the product was extruded through a 750 mm wide flat die and then gathered on 3 cooled rolls.
• An additional natural cooling bench was used to stabilize the formed sheets.
• Composition I.V. Tensile 120 D impact dl/g modulus (GPa) strength (J/m)
• a dynamic extensometer (12.5 mm) has been used to avoid sam ⁇ ples slipping between the clamps.
• Impact properties have been checked using an Isod impact te ⁇ ster Ceast using a 2 J hammer and notched specimens cut out from original sheets. At least 5 specimens for each sample were be tested.

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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)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Polyesters Or Polycarbonates (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Reinforced Plastic Materials (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
• Laminated Bodies (AREA)
• Macromonomer-Based Addition Polymer (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

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• 1993
  • 1993-05-07 IT IT93MI000916A patent/IT1264381B1/it active IP Right Grant
• 1994
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