Abstract: Described herein is a feasible, significantly simplified production method that avoids challenging lactonization steps and converts a low molecular weight aliphatic polyester, consisting of hydroxy acids and a comonomer, whose molecular weight has been increased by step-growth polymerization reactions. The molecular weight of the aliphatic polyester, based on comparison of initial and final weight average molecular weights (Mw,1/Mw,2), increased significantly at a rate which permits the use of reactive extrusion to produce high molecular weight aliphatic polyesters in a simple, economically feasible manner.

Abstract: A process for making a high molecular weight poly(hydroxy acid) polymer having good thermal stability and a weight average molecular weight of >100,000 by GPC. The process includes mixing glycolic acid and/or lactic acid, and a diol or di-acid initiator, and at least one multifunctional initiator to form a liquid monomer mixture in an agitated polycondensation reactor. Polycondensing to form a liquid reaction mixture comprising a pre-polymer having a weight average molecular weight of >10,000 by GPC, and greater than 80% by mole hydroxyl or carboxyl end-group termination, then crystallizing to form a first solid reaction mixture. Then solid state polycondensing the solid reaction mixture to form a solid reaction mixture having a moisture level less than 50 ppm by weight. Then mixing the solid reaction mixture with an appropriate reactive coupling agent in a melting and mixing extruder to couple and form the reaction mixture and form the poly(hydroxy acid) polymer.

Abstract: A process for making a high molecular weight poly(hydroxy acid) polymer having good thermal stability and a weight average molecular weight of >100,000 by GPC. The process includes mixing glycolic acid and/or lactic acid, and a diol or di-acid initiator, and at least one multifunctional initiator to form a liquid monomer mixture in an agitated polycondensation reactor. Polycondensing to form a liquid reaction mixture comprising a pre-polymer having a weight average molecular weight of >10,000 by GPC, and greater than 80% by mole hydroxyl or carboxyl end-group termination, then crystallizing to form a first solid reaction mixture. Then solid state polycondensing the solid reaction mixture to form a solid reaction mixture having a moisture level less than 50 ppm by weight. Then mixing the solid reaction mixture with an appropriate reactive coupling agent in a melting and mixing extruder to couple and form the reaction mixture and form the poly(hydroxy acid) polymer.

Abstract: Described herein is a feasible, significantly simplified production method that avoids challenging lactonization steps and converts a low molecular weight aliphatic polyester, consisting of hydroxy acids and a comonomer, whose molecular weight has been increased by step-growth polymerization reactions. The molecular weight of the aliphatic polyester, based on comparison of initial and final weight average molecular weights (Mw,1/Mw,2), increased significantly at a rate which permits the use of reactive extrusion to produce high molecular weight aliphatic polyesters in a simple, economically feasible manner.

Abstract: The present invention relates to a method for preparation a glycolide polyester by ring opening polymerization characterized in that glycolide monomer with optional co-monomer(s) of cyclic ester(s) is/are subjected to ring opening polymerization in the presence of a dispersion stabilizer and a catalyst, said catalyst being selected for precipitating glycolide homopolymer or copolymer from solvent, said solvent being selected so that the glycolide monomer and the optional co-monomer(s), the dispersion stabilizer and the catalyst are soluble therein but said glycolide homopolymer or copolymer is non-soluble. The present invention further relates to an in situ ring opening polymerizing process product, and to use of said glycolide polyester, and to further processing of said glycolide polyester.

Abstract: Described herein is a feasible, significantly simplified production method that avoids challenging lactonization steps and converts a low molecular weight aliphatic polyester, consisting of hydroxy acids and a comonomer, whose molecular weight has been increased by step-growth polymerization reactions. The molecular weight of the aliphatic polyester, based on comparison of initial and final weight average molecular weights (Mw,1/Mw,2), increased significantly at a rate which permits the use of reactive extrusion to produce high molecular weight aliphatic polyesters in a simple, economically feasible manner.

Abstract: The present invention relates to a method for preparation a glycolide polyester by ring opening polymerization characterized in that glycolide monomer with optional co-monomer(s) of cyclic ester(s) is/are subjected to ring opening polymerization in the presence of a dispersion stabilizer and a catalyst, said catalyst being selected for precipitating glycolide homopolymer or copolymer from solvent, said solvent being selected so that the glycolide monomer and the optional co-monomer(s), the dispersion stabilizer and the catalyst are soluble therein but said glycolide homopolymer or copolymer is non-soluble. The present invention further relates to an in situ ring opening polymerizing process product, and to use of said glycolide polyester, and to further processing of said glycolide polyester.

Abstract: The invention provides a syringe barrel formed by injection moulding of a polypropylene composition, characterised in that said polypropylene composition contains a polyethylene wax. The invention further provides a syringe having a barrel formed by injection moulding of a polypropylene composition, characterised in that said polypropylene composition contains a polyethylene wax and a polypropylene composition suitable for such moulding.

Abstract: A process for the production of a propylene based polymer, the process comprising the following steps: (a) a first polymerization stage comprising homopolymerizing propylene or copolymerizing propylene and at least one alpha-olefin in the presence of an alpha-olefin polymerization catalyst whereby to produce a polypropylene component; (b) a second polymerization stage comprising copolymerizing ethylene and at least one alpha-olefin in the presence of an alpha-olefin polymerization catalyst whereby to produce an ethylene/alpha-olefin copolymer component; and (c) blending the polymer components produced in steps (a) and (b) whereby to produce a polymer blend, wherein the first and second polymerization stages are effected in separate polymerization reactors connected in parallel.

Abstract: The invention provides a syringe barrel formed by injection moulding of a polypropylene composition, characterised in that said polypropylene composition contains a polyethylene wax. The invention further provides a syringe having a barrel formed by injection moulding of a polypropylene composition, characterised in that said polypropylene composition contains a polyethylene wax and a polypropylene composition suitable for such moulding.

Abstract: The invention provides a process for the production of a propylene based polymer, said process comprising the following steps: (a) a first polymerization stage comprising homopolymerizing propylene or copolymerizing propylene and at least one &agr;-olefin in the presence of an &agr;-olefin polymerization catalyst whereby to produce a polypropylene component; (b) a second polymerization stage comprising copolymerizing ethylene and at least one &agr;-olefin in the presence of an &agr;-olefin polymerization catalyst whereby to produce an ethylene/&agr;-olefin copolymer component; and (c) blending the polymer components produced in steps (a) and (b) whereby to produce a polymer blend, wherein said first and second polymerization stages are effected in separate polymerization reactors connected in parallel.

Abstract: The present invention concerns a process for producing a propylene polymer nucleated with a polymeric nucleating agent containing vinyl compound units. The method comprises modifying a catalyst by polymerizing a vinyl compound in the presence of said catalyst in a medium, which does not essentially dissolve the polymerized vinyl compound, and by continuing the polymerization of the vinyl compound until the concentration of unreacted vinyl compounds is less than about 0.5 wt-%. The thus obtained modified catalyst composition is used for polymerizing propylene optionally together with comonomers to produce in the presence of said modified catalyst composition. Modification of the catalyst according to the present invention will reduce production costs and provide highly reliable catalyst activity.

Abstract: The present invention concerns a multilayered polymer film structure, which comprises at least one first layer (1) containing a thermoplastic polymer and at least one second layer (2), arranged adjacent to said first layer, containing a liquid crystalline polymer. According to the invention, the second layer (2) consists essentially of a compounded polymer blend formed by the liquid crystalline polymer and a thermoplastic polymer, the liquid crystalline polymer of the second layer forms a continuous phase, and the first and the second layers (1, 2) contain the same thermoplastic polymer. The oxygen transmission rate of the second layer is less than about 150 cm3/(m2·d·bar), determined according to the standard ASTM D 3985-81, and the water vapour transmission rate of the integral film structure is less than 10 g/(m2·24·h) at RH 80% 23° C., determined according to ASTM F 1249-90. The present structure can be used as a barrier layer in packages.

Abstract: The invention relates to a process for the preparation of a creep-resistant polypropylene by means of the following steps: (a) copolymerizing propylene and ethylene into a random copolymer at 40 to 110° C. using: a catalyst system of the above-mentioned type; a portion of ethylene or C4-C10-&agr;-olefin leading to 1.0 to 10.0% by weight of ethylene repeating units in said random copolymer; and no or a minimal amount of hydrogen leading to a MFR10 value of between 0.01 and 5.0 g/10 min for said random copolymer, if this step is performed first, or to a MFR2 value for said polypropylene of between 0.05 and 0.40 g/10 min, if this step is performed after step (b); the proportion of random copolymer of this step being from 20 to 80% by weight of said polypropylene, (b) polymerizing propylene at 40 to 110° C. using: a catalyst system of the above-mentioned type; no or a minimal portion of ethylene leading to 0.0 to 1.

Abstract: The lamellar layer is formed by overlapping plates of the liquid crystalline polymer in the isotropic matrix. The oxygen transmission rate of a 50 .mu.m thick layer of the monolayer structure is typically less than 150 cm.sup.3 /(m.sup.2 .multidot.d.multidot.bar).

Abstract: The invention concerns a novel melt-processible poly(ester urethane) and a process and a prepolymer for the preparation thereof. The poly(ester urethane) contains structural units derived from a polyester and structural units derived from a diisocyanate and, according to the invention, the bonds between the structural units are at least mainly comprised of urethane bonds, the number average molar mass, M.sub.n, of the prepolymer is at least 10,000 g/mol, its mass-average molar mass, M.sub.w, is over 20,000 g/mol and its molar mass distribution, expressed as the ratio of M.sub.w /M.sub.n, is over 2, and the prepolymer is essentially free from free isocyanate groups. The poly(ester urethane) is hydrolytically decomposable and it can be used as a biodegradable polymer, e.g., for manufacturing injection molded pieces and thermoformed and blow molded packages, bags, sacks and bottles, for coating of sacks, bags and films made of paper or cardboard, and for manufacturing fibers and non-woven fabrics.

Abstract: The invention concerns a novel melt-processible copolyester and a process and prepolymer for the preparation thereof. The copolyester contains structural units derived from a polyester and structural units derived from diepoxy, and the polyester units at least essentially consist of hydroxy acid monomers. The bonds between the structural units are ester bonds and the number average molar mass, M.sub.n, is at least 10,000 g/mol, its weight average molar mass, M.sub.w, is over 20,000 g/mol and molar mass distribution, expressed as the ratio M.sub.w /M.sub.n, is over 2. The copolyester is hydrolytically degradable and it can be used as a biodegradable polymer for the manufacture of injection moulded articles as well as thermoformed and blow moulded packages, pouches, sacks and bottles, for the coating of sacks bags and films made from paper or cardboard and for the preparation of fibres, fibre cloths and expanded polymer articles.

Abstract: Olefins or mixtures of olefins, particularly propene or mixtures of propene advantageously with ethene, can be polymerized using a Ziegler-Natta catalyst system containing, besides a transition-metal-based procatalyst and cocatalyst which is an organometallic compound, a compound particularly suited for controlling the stereospecificity of the produced polymer. Such a compound called an external donor may also have other effects. By using an acetal derivative of an aldehyde that has two ether groups for this purpose, advantageously selected from the group of dialkoxyphenylalkanes, e.g., dimethoxyphenylpropane, a good stereospecificity of the product is attained combined with the high hydrogen sensitivity of the catalyst system, whereby the use of hydrogen as the chain transfer agent offers an easy control method of the molecular weight of the product by means of adjusting the amount of hydrogen available in the polymerization reaction.

Abstract: A melt-processable block copolyesterimide comprising the repeating units (I), (II) and (III) and, optionally, a repeating unit (IV), wherein (I) is a repeating unit of the formula ##STR1## wherein R is an aliphatic polyether chain and/or a polysiloxane chain; (II) and (III) are repeating units of the formulas ##STR2## wherein Z is hydrogen, alkyl, alkoxy, aryl, halogen and w is zero or one; and (IV) is a repeating unit of the formula ##STR3## wherein Z' is hydrogen, alkyl, alkoxy, aryl or halogen and the phenylene ring is substituted in by Z' in the m- or p-positions. The repeating unit of formula (I) is present in an amount of 5 to 50 mole-%, the repeating unit of formula (II) is present in an amount of 10 to 80 mole-%, the repeating unit of formula (III) is present in an mount of 5 to 50 mole-% and the repeating unit of formula (IV) is present in an amount of 0 to 45 mole-% of the block copolyesterimide.

Abstract: A good activity and stereospecifity have been achieved by a catalyst system intended for the polymerization of olefins comprising a procatalyst based on a titanium compound, an organoaluminium cocatalyst and an organosilane compound, the organosilane compound having the following formula (I) ##STR1## in which R is a lower alkyl, R' is an alkyl, R" is a substituent donating electrons, n=1, 2, or 3, m=0, 1, or 2, and n+m.ltoreq.3.