Abstract: The invention relates to screw elements for multi-screw extruders with screws co-rotating in pairs and being fully self-wiping in pairs, to the use of the screw elements in multi-screw extruders and to a process for extruding plastic compositions.

Abstract: The invention relates to a method for recycling polyesters or polyester mixtures from polyester-containing waste, in which the polyester or the polyester mixture is dissolved in a solvent and subsequently free-flowing particles are precipitated herefrom with a precipitant. The precipitant is thereby chosen such that subsequent separation of precipitant and solvent is made possible in a simple manner.

Abstract: The invention relates to a process for making an opaque and glossy film from a thermoplastic polyester composition, comprising the steps of a) extruding the polyester composition through a slot die, and quenching to form a substantially amorphous film having a crystallinity of at most 5%; b) rapidly heating the amorphous film to a drawing temperature in the range from Tg to (Tg+50)° C. while applying a draw ratio in the range of from ?initiation to ?max. in longitudinal direction, and a drawing rate of at least 1 m/min to form an oriented film showing stress-whitening, wherein ?initiation is the draw ratio at which a transfer from a transparent product to a stress-whitened product occurs and ?max. is the draw ratio at which failure of the stress whitened film occurs; and c) heat-setting the oriented stress-whitened film; the thermoplastic polyester composition substantially consisting of at least one crystallisable polyester derived from at least one aliphatic diol and at least one aromatic dicarboxylic acid.

Abstract: The invention relates to a process for making modified polybutylene terephthalate random copolymers from a polyethylene terephthalate component. In one embodiment, the invention relates to a two step process in which a 1,4-butane diol component reacts with a polyethylene terephthalate component under conditions that depolymerize the polyethylene terephthalate component into a molten mixture and the molten mixture is placed under subatmospheric conditions that produce the modified polybutylene terephthalate random copolymers.

Abstract: A bulk of polyester polymer particles comprising polyester polymer comprising greater than 75% virgin polyester polymer, the particles having: A) an It.V. of at least 0.72 dl/g, and B) 10 ppm or less of residual acetaldehyde; and C) at least two melting peaks, wherein one of said at least two melting peaks is a low peak melting point within a range of 140° C. to 220° C. and having a melting endotherm area of at least the absolute value of 1 J/g. The particles may also have a degree of crystallinity within a range of 20% and a maximum degree of crystallinity Tcmax defined by the equation: Tcmax=50%?CA?OH where CA is the total mole % of all carboxylic acid residues other than terephthalic acid residues, based on 100 mole % of carboxylic acid residues, and OH is the total mole % of all hydroxyl functional compound residues other than ethylene glycol residues, based on 100 mole % of hydroxyl functional compounds residues.

Abstract: A molding composition comprising (a) from 5 to 90 wt % of a modified polybutylene terephthalate random copolymer that (1) is derived from polyethylene terephthalate component selected from the group consisting of polyethylene terephthalate and polyethylene terephthalate copolymers and (2) at least one residue derived from the polyethylene terephthalate component, and (b) from 5 to 40 wt % of a polyalkylene terephthalate component; wherein the modified polybutylene terephthalate random copolymer, the polyalkylene terephthalate component, and optionally, at least one additive, have a combined weight % of 100 wt %. Methods for making the composition and articles made from the composition.

Abstract: A process for preparing modified polymer by withdrawing a slip stream of polymer melt from the discharge line of a continuous polymerization reactor, admixing in a highly modified polymeric additive into the polymer melt within the slip stream, then introducing the modifier containing slip stream late in the manufacturing process prior to the slip stream withdrawal point. The improved processes of the invention have particular utility for large-scale, continuous reactor where transitions and short production runs are economically prohibitive thereby limiting the product breath. The process is particularly suited for producing a family of copolyesters using a continuous melt phase production process.

Abstract: The invention relates to a method for producing a high-molecular polyester from a solidified polyester prepolymer by solid phase polycondensation. The polycondensation cleavage products of the solid phase polycondensation reaction are extracted from the product by means of a process gas, and the process gas is then cleaned and essentially recycled. According to the invention, the process gas is cleaned by means of an aqueous washing liquid. The invention also relates to an installation for carrying out the inventive method, said installation containing a crystallisation appliance (1) and a reaction appliance (2). A gas outlet (2d) of the reaction appliance (2) is directly or indirectly connected to a gas inlet (3c) in a gas cleaning system (3), and a gas outlet (3d) of the gas cleaning system (3) is connected to a gas inlet (2c) of the reaction appliance (2).

Abstract: The invention relates to a method for producing a semicrystalline polymer, said method comprising the following steps: producing a polymer melt from a crystallizable polymer; shaping particles and solidifying the polymer melt, the step of shaping the particles being carried out before or after solidification; cooling the particles; treating the particles to reduce their tendency to agglomerate; crystallizing the particles. The invention is characterized in that the treatment is carried out by shaking at a temperature T1 which is below the glass transition temperature of the polymer plus 10° C., i.e. T1<Tg+10° C.

Abstract: The invention relates to a process for making modified polybutylene terephthalate random copolymers from a polyethylene terephthalate component. The invention relates to a three step process in which a diol component selected from the group consisting of ethylene glycol, propylene glycol, and combinations thereof reacts with a polyethylene terephthalate component under conditions sufficient to depolymerize the polyethylene terephthalate component into a first molten mixture; and where the first molten mixture is combined with 1,4-butanediol under conditions that create a second molten mixture that is subsequently placed under subatmospheric conditions that produce the modified polybutylene terephthalate random copolymers. The invention also relates to compositions made from the process.

Abstract: A process in which a wound roll of biaxially oriented polyester film having a glass transition temperature (Tg (° C.)) is annealed at a temperature Ta (° C.) above Tg where Tg<Ta?Tg+100 (° C.) for a time t after thermal equilibrium where 1 hour?t?72 hours and cooled, for the purpose of improving the shrinkage of said polyester film.

Abstract: Processes for making polyesters in a polyester production facility are disclosed, that include the steps of: forming a reaction medium comprising at least one monomer that includes terephthalic acid (TPA) and/or an ester derivative of TPA; subjecting at least a portion of the reaction medium to one or more chemical reactions in the polyester production facility to thereby produce the polyester; heating at least a portion of the reaction medium via indirect heat exchange with high-pressure steam, wherein the heating causes at least a portion of the high-pressure steam to condense and thereby provide pressurized condensed water; flashing at least a portion of the pressurized condensed water to thereby produce lower-pressure steam; and heating one or more process fluid streams of the polyester production facility via indirect heat exchange with at least a portion of the lower-pressure steam, wherein the process fluid streams include any stream that is formed predominately of the reaction medium and/or the at lea

Abstract: Integrated processes for making polyesters are disclosed, that include the steps of: (a) producing an aromatic polycarboxylic acid in a monomer production facility; (b) producing a polyester in a polyester production facility, wherein the producing of the polyester comprises the substeps of: (i) forming a polyester reaction medium comprising at least a portion of the aromatic polycarboxylic acid from the monomer production facility, (ii) subjecting at least a portion of the polyester reaction medium to one or more chemical reactions to thereby produce the polyester, (iii) heating the polyester reaction medium at one or more locations in the polyester production facility via indirect heat exchange with high-pressure steam, wherein the heating causes at least a portion of the high-pressure steam to condense and thereby provide pressurized condensed water, and (iv) flashing at least a portion of the pressurized condensed water to thereby produce lower-pressure steam; and (c) using at least a portion of the lower

Abstract: The invention relates to a method for producing a high-molecular polycondensate from a solidified polycondensate prepolymer by solid phase polycondensation. According to said method, the polycondensation cleavage products of the solid phase polycondensation reaction are extracted from the product by means of a process gas, and the process gas is then cleaned of the polycondensation cleavage products and essentially recycled. According to the invention, the specific energy input is less than 120 kWh/t, preferably less than 110 kWh/t and especially between 70 and 100 kWh/t. The invention also relates to an installation for producing a high-molecular polycondensate, said installation comprising a heating appliance (1), followed by a crystallisation appliance (2), a reaction appliance (4), and a cooling appliance (5).

Abstract: A method of crystallizing a plurality of crystallizable polymer pellets includes a step in which the pellets passed through regions that are temperature adjusted by a heat transfer jacket. The heat transfer jacket adjusts the temperature of the pellets by having a temperature sufficient to allow at least partial crystallization of the plurality of polymeric pellets while maintaining the average pellet temperature of the plurality of pellets below the melting temperature of the pellets. A crystallizer implementing the methods of the invention is also provided.

Abstract: To provide an efficient process for producing polyester particles from a polyester with a low degree of polymerization by a strand cutting method, polyester particles, a process for producing polyester resin particles from the polyester particles by solid phase polycondensation, and polyester resin particles. A process for producing polyester particles, characterized in that the following steps (1) to (3) are sequentially carried out, and the drawing rate ratio of polyester strands represented by the following formula is from 1.5 to 100, polyester particles, a process for producing polyester resin particles which comprises subjecting the particles to solid phase polycondensation, and polyester resin particles: (1) a step of discharging a molten polyester having a melt viscosity of from 0.

Abstract: Macrocyclic oligoesters and compositions comprising macrocyclic oligoesters are prepared from intermediate molecular weight polyesters. In one embodiment, a diol is contacted with a dicarboxylic acid or a dicarboxylate in the presence of a catalyst to produce a composition comprising a hydroxyalkyl-terminated polyester oligomer. The hydroxyalkyl-terminated polyester oligomer is heated to produce a composition comprising an intermediate molecular weight polyester which preferably has a molecular weight between about 20,000 Daltons and about 70,000 Daltons. The intermediate molecular weight polyester is heated and a solvent is added prior to or during the heating process to produce a composition comprising a macrocyclic oligoester. An optional step is to separate the macrocyclic oligoester from the composition comprising the macrocyclic oligoester.

Abstract: A method for manufacturing a crystallizable plastic material is disclosed. The process includes the step of melting an amorphous plastic material, pelletizing the material, crystallizing it and then post condensing the plastic material with the proviso that the plastic material is not subjected to heating after the melting step but prior to the crystallization step and then subjecting the plastic material to sieving after the crystallization step.

Abstract: The invention relates to a process of preparing glycol carboxyethylmethylphosphinate, which comprises a) reacting elemental yellow phosphorus with methyl chloride in the presence of an alkali or alkaline earth metal hydroxide to form a mixture which includes the alkali and/or alkaline earth metal salts of methylphosphonous, phosphorous and hypophosphorous acids as main constituents, b) esterifying the methylphosphonous acid from the mixture obtained by a), c) removing the methylphosphonous ester from the mixture, d) adding the thus obtained methylphosphonous ester to an acrylic ester, e) hydrolyzing the diester thus obtained, f) esterifying the resulting carboxyethylmethylphosphinic acid with ethylene glycol directly to the glycol carboxyethylmethylphosphinate. The invention also relates to the use of the glycol carboxyethylmethylphosphinates prepared according to the invention as reactive flame retardants for polymers.

Abstract: A transparent film whose thickness is in the range from 1 to 500 ?m and which comprises, as principal constituent, a crystallizable thermoplastic, wherein the film comprises at least one UV stabilizer as light stabilizer and at least one optical brightener, and to the use of the film, and also to a process for its production.

Abstract: The present invention discloses a process for the preparation of a stabilized polyester that is low in the generation of aldehydes which comprises reacting one or more diacids with one or more diols in an esterification process, and/or one or more diesters with one or more diols in a transesterification process in the presence of an effective amount of a stabilizer selected from the group consisting of (a) a polyhydric alcohol which is for example poly(ethylene-co-vinyl alcohol), poly(styrene-co-allyl alcohol), maltitol, isomalt, sorbitol, xylitol, sucrose, mucic acid dibutylester, mucic acid di(phenyl-1-ethyl)ester, pentaerythritol or dipentaerythritol; (b) a compound of the formula II, which is for example di-iso-octyl-phosphinic acid; (c) a sterically hindered amine which is for example Tinuvin 123 or Tinuvin 622; (d) a polyacrylamide or a cationic acrylamide copolymer, or (e) a hydroxyamine and/or a nitrone.

Abstract: The invention relates to a method for treating plastic material, especially polyethylene terephthalate, wherein the relatively low temperature material is initially crystallized by heating before subjecting said material to heating or condensation in the solid phase. The material is then exposed to a hot treatment gas for at least 10 minutes in at least two chambers (2) of an apparatus and crystallized at a temperature above 135° C., e.g. 140-180° C. The is subsequently heated in a preheating chamber (3) having at least one to eight stages at a temperature of at least 185° C., preferably at least 200° C. and more preferably around 220° C.

Abstract: A preblended additive composition and process for the preparation of polyester resins useful in the manufacture of plastic containers such as bottles is disclosed. The additive composition includes a cobalt-containing compound that is preblended with a phosphorous compound. The polyester resin, e.g., a PET resin, may be prepared by reacting ethylene glycol with dimethyl terephthalate (DMT) or terephthalic acid (TA) in an esterification reaction. The additive composition may be prepared by quickly dumping the phosphorus compound into the cobalt compound such as cobalt acetate, and the resulting composition is added to the reactor vessel before the polycondensation reaction. On the other hand, the additive composition may be prepared by slowly dumping the phosphorus compound into the cobalt compound over a period of at least 5 minutes. Such preblending substantially eliminates any yellow or blue color, or haze in the product article.

Abstract: Mono- or biaxially-stretched polyester resin foamed sheets and films wherein the polyester resin has a melt strength of more than 1 centinewton at 280° C., a melt viscosity of at least 1500 Pa.s at 280° C. for a shear ratio which tends to zero and a crystallization rate such that for a 10-minute heating at 120° C. the crystallinity can reach values as high as 30-35%.

Abstract: Disclosed is a process for preparing a high modulus and a low shrinkage polyester multifilament yarn of 1000 deniers or more at a spinning rate of 2,000 m/min or more, comprising the steps of: melt-extruding polyester chips having an intrinsic viscosity of 0.90 to 1.2 through a spinning nozzle and passing polyester chips through a heating zone; quenching melt-extruded yarns with the use of a radial in-to-out quenching method to solidify them; and providing spin finishes to solidified yarns before winding. The industrial polyester multifilament yarns have a coefficient of variation of 4.0% or less in a cross sectional diameter of filaments, and excellent uniformity of fineness. Treated cords formed from the industrial polyester multifilament yarns with high modulus and low shrinkage have an excellent dimensional stability and tenacity, and can be used as reinforcements of rubber goods such as tires.

Abstract: The present invention relates to a method for treating plastic polymers to reduce or remove organic contaminants. More particularly, the present invention relates to a method of treating, by continuous means, a flowable polymer mass with a solvating fluid in an environment at which the solvating fluid is in a supercritical state and is subject to conditions sufficient to preferentially solvate and extract organic, and especially non-volatile, contaminants from the polymer mass.

Abstract: A method of making a polyethylene terephthalate/polyolefin blend for sheeting and thermoformed articles which has improved color stability and can be recycled many times. A heat stabilizer is melt blended only with the polyolefin prior to its incorporation into the polyethylene terephthalate. The PET and polyolefin are then blended and extruded into sheeting and subsequently thermoformed into articles useful as microwave oven trays.

Abstract: The present invention provides a catalyst for polyester production capable of producing a polyester with high catalytic activity, a process for producing a polyester using the catalyst and a polyester produced thereby. The catalyst comprises a solid titanium compound obtained by dehydro-drying a hydrolyzate obtained by hydrolysis of a titanium halide and which has a molar ratio (OH/Ti) of a hydroxyl group (OH) to titanium (Ti) exceeding 0.09 and less than 4. In the process, the polyester is obtained by polycondensing an aromatic dicarboxylic acid, or an ester-forming derivative thereof, and an aliphatic diol, or ester-forming derivative thereof, in the presence of the catalyst. The resulting polyester has excellent transparency and tint, a titanium content of 1 to 100 ppm, a magnesium content of 1 to 200 ppm and a magnesium to titanium weight ratio of not less than 0.01.