MXPA00010289A - Polyester container and method for making same - Google Patents

Abstract

A polyester container made from a polymer having ethylene glycol moieties, isosorbide moieties and terepthaloyl moieties, and the method of making the container is described. The polyester container is suitable for holding liquids and solids, and may be hot-filled or cold-filled. In particular, wide-mouth jars and narrow-necked bottles may be formed. The polyester has an inherent viscosity of at least 0.35 dL/g when measured as a 1%(weight/volume) solution of the polyester in o-chlorophenol at a temperature of 25°C.

Description

POLYESTER PACKAGING AND METHOD FOR ELABORATION FIELD OF THE INVENTION This description relates to polyester containers and methods for their preparation, in particular relates to polyester packages having a portion of isosorbide, a portion of terephthaloyl and a portion of ethylene glycol, and methods for making the same.

BACKGROUND OF THE INVENTION Plastic containers are widely used for food and beverages, and also for non-food materials. Poly (ethylene terephthalate) (PET) is used to make many of these containers because of their appearance (optical transparency), ease of blow molding, chemical and thermal stability as well as their price. PET is generally manufactured in bottles by a blow molding process, and generally by blow-molding and stretching. In blow-molding and stretching, the PET is first formed by injection molding in a preformed thick-walled parison (a "preform"), which typically has the shape of a tube with a threaded opening in the top.

Ref: 123437 The parison can be cooled and then used later in a subsequent stage, or the process can be carried out in a machine with cooling only up to the temperature of blow molding and stretching. In the stretch blow molding stage, the parison is heated to a sufficiently high temperature in a mold to allow its shaping, but not so hot that it crystallizes or melts (i.e., just above the glass transition temperature, Tg, typically from about 90 ° to 160 ° C). The parison expands to fill the mold by rapidly stretching mechanically in the axial direction (e.g., by using a mandrel), while simultaneously blowing air under pressure into the heated parison to radially expand it. PET is typically modified by blow molding with a small amount of comonomer, usually 1,4-cyclohexanedimethanol or isophthalic acid, which increases the width of the temperature range for successful blow molding at about 9 ° C. The comonomer is necessary due to the need to have a wider temperature range, and also to decrease the voltage velocity induced by crystallization. At the same time, the monomer can have an undesirable effect by decreasing the vitreous transition temperature and reducing the crystallinity of PET. PET blow and stretch molding, and the blow molding process in general, are well known in the art. Reviews are widely available, for example, "Blo Molding" by C. Irwin in Encyclopedia of Polymer Science and In ineering, Second Edition. Vol. 2, John Wiley and Sons, New York, 1985, pp. 447-478. This technology is widely used, but there are still improvements that need to be made. First, a wider temperature range for blow molding can greatly improve the process. Second, a material that can be filled with liquid or solid foods at higher temperatures than those currently used can significantly expand the utility of the bottles by allowing packaging at elevated temperatures of up to 88 ° C, and preferably higher, as required for pasteurized foods, beverages and syrups that are too viscous for transfer without heating. The maximum filling temperature for PET bottle resin grades is generally about 60 ° C to 65 ° C. It is generally considered that a resin with a higher Tg is better for this purpose. PET bottles are currently modified for hot filling applications by annealing the bottles in a hot mold for a few seconds immediately after blow-molding and stretching. This allows PET, which is oriented during blow-molding and stretching, partially crystallize before the bottle is unmoulded and cooled. This can be done in such a way that the crystallinity is low enough and that the crystallite size is small enough so that the bottle is still transparent. The crystallites in the PET bottle apparently stabilize the bottle so that they can be exposed to hot liquids, which are at a temperature of up to about 88 ° C, during a hot filling process, without deformation. The annealing step significantly prolongs the time needed to make a bottle, resulting in reduced productivity and higher costs. Therefore, a polymer which has a high Tg and low crystallinity to form hot and cold filled packages is desirable. The diol 1,4: 3,6-dianhydro-D-sorbitol, hereinafter referred to as isosorbide, the structure of which is illustrated below, is easily manufactured from renewable resources, such as sugars and starches. For example, isosorbide can be made from D-glucose by hydrogenation followed by acid-catalyzed dehydration.

Isosorbide has been incorporated as a monomer in polyesters that also include terephthaloyl moieties. See, for example, R. Storbeck et al, Makromol. Chem., Vol. 194, pp. 53-64 (1993); R. Storbeck et al, Polymer. Vol. 34, p. 5003 (1993). However, it is generally considered that secondary alcohols such as isosorbide have little reactivity and are sensitive to acid catalyzed reactions. See, for example D. Braun et al., J. Prakt. Chem .. Vol. 334, pp. 298-310 (1992). As a result of the poor reactivity, polyesters made with an isosorbide monomer and the terephthalic acid esters are expected to have a relatively low molecular weight. Ballauff et al, Polyesters (Derived from Renewable Sources), Polymeric Materials Encyclopedia, Vol. 8, p. 5892 (1996). Copolymers containing portions of isosorbide, portions of ethylene glycol and portions of terephthaloyl have been reported only rarely. A copolymer containing these three portions, in which the ratio and moles of ethylene glycol to isosorbide is about 90:10, are reported in published German patent application No. 1,263,981 (1968). The polymer is used as a minor component (approximately 10%) of a combination with polypropylene to improve the dyeability of the polypropylene fiber. It is made by melt polymerization of dimethyl terephthalate, ethylene glycol and isosorbide, but the conditions which are described are only mentioned in general terms in the publication, and a polymer having a high molecular weight is not provided. The copolymers of these same three monomers are described again in a recent manner, where it has been observed that the glass transition temperature Tg of the copolymer is increased with an isosorbide monomer content of up to about 200 ° C for the isosorbide terephthalate homopolymer . The polymer samples are made by reacting terephthalate dichloride in solution with the diol monomers. This method provides a copolymer with a molecular weight that is apparently higher than that obtained in the German patent application described above but still relatively low in comparison to other polyester polymers and copolymers. In addition, these polymers are manufactured by solution polymerization and are therefore free of diethylene glycol portions as a polymerization product. See R. Storbeck, Dissertation, Universitát Karlsruhe (1994); R. Storbeck, et al., J. Appl. Polymer Science. Vol. 59, pp. 1199-1202 (1996). U.S. Patent 4,418,174 describes a process for the preparation of polyesters useful as raw materials in the production of aqueous baked lacquers.

The polyesters are prepared with an alcohol and an acid. One of the many preferred alcohols is dianhydrosorbitol. However, the average molecular weight of the polyesters is from 1,000 to 10,000, and a polyester containing an anhydrous sorbitol portion is not actually produced. U.S. Patent 5,179,143 describes a process for the preparation of compression molded materials. In addition, polyesters containing hydroxyl are disclosed therein. These hydroxyl-containing polyesters are listed to include polyhydric alcohols including 1, 4: 3, 6-dianhydrosorbitol. However, again, the highest molecular weights reported are relatively low, that is, from 400 to 10,000 and in fact a polyester containing the 1, 4: 3, 6-dianhydrosorbitol portion is not made. Published PCT applications WO 97/14739 and WO 96/25449 disclose cholesteric and nematic liquid crystalline polyesters including portions of isosorbide as monomer units. Such polyesters have relatively low molecular weights and are not isotropic.

BRIEF DESCRIPTION OF THE INVENTION Contrary to the teachings and hopes that have been published in the prior art, the isotropic, ie semicrystalline and amorphous or non-liquid crystalline copolymers containing portions of terephthaloyl, portions of ethylene glycol, portions of isosorbide and, optionally, portions of diethylene glycol, are easily synthesized in molecular weights which are suitable for making manufactured products such as packaging, on an industrial scale. The packages made of such polyesters provide improved strength, a higher Tg and lower crystallinity for example. In particular, packages made of such polyesters are suitable for cold filling and hot filling applications. The process conditions for producing a polyester container, particularly the amounts of monomers used in the polyester, are desirably chosen so that the final polymer product used for packaging manufacture has the desired amounts of the various monomer units, preferably with equimolar amounts of monomer units derived from a diol and a diacid. Due to the volatility of some of the monomers, including isosorbide, and depending on the method of making the polyester, some of the monomers are desirably excessively included at the start of the polymerization reaction and are removed as the reaction proceeds. This is particularly true for ethylene glycol and isosorbide. The polyester can be formed by any method known in the art. However, preferably, the polyester is formed by solvent or melt polymerization. The choice of method can be determined by the desired amount of diethylene glycol in the final product. In a preferred embodiment, the number of terephthaloyl moieties in the polymer is in the range of about 25% to about 50 mole% (moles% of the total polymer). The polymer may also include amounts of one or more aromatic diacid portions such as, for example, those derived from isophthalic acid, 2,5-furanodicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2, 7 acid. -naphthalenedicarboxylic acid and 4,4'-benzoic acid at combined concentrations of up to about 25 mole% (moles% of total polymer). In a preferred embodiment, units of ethylene glycol monomers are present in amounts of about 5 mol% to about 49.75 mol%. The polymer may also contain portions of diethylene glycol. Based on the manufacturing method, the amount of diethylene glycol portions is in the range of about 0.0 mole% to about 25 mole%. In a preferred embodiment, the isosorbide is present in the polymer in amounts in the range of about 0.25 mol% to about 40 mol%. One or more different diol monomer units may also be included, in amounts up to a total of about 45 mole%. The polyester has an inherent viscosity, which is an indicator of molecular weight, of at least about 0.35 dl / g, measured in a 1% (w / v) solution in o-chlorophenol at a temperature of 25 ° C. A higher inherent viscosity, such as for example about 0.40 dl / g, preferably at least about 0.50 dl / g, is desired for optimum formation of a package. Further processing of the polyester can generate inherent viscosities of up to about 2.0 dl / g and even higher. The polyester packages of the present invention are suitable for holding beverages, food and other solids and liquids, and can be filled with hot or cold substances. In particular, these packages provide high Tg, increased strength and reduced crystallinity.

DETAILED DESCRIPTION OF THE INVENTION Polyester packages and a method for their manufacture are described in detail in the following. In particular, the method for making a polyester comprising portions of terephthaloyl, portions of ethylene glycol and isosorbide is described, as well as the process for forming packages from such a polymer. In a preferred embodiment, the ethylene glycol monomer units are present in the polymer in amounts of about 28 mol% to about 49.75 mol%, preferably from about 33 mol% to about 49.5 mol%, and more preferably about 37 mole% to about 45 mole%, and much more preferably from about 41 mole% to about 49 mole%, although larger amounts may be included as necessary to obtain the desired results. The polymer composition may also contain diethylene glycol monomer units. Depending on the manufacturing method, the amount of diethylene glycol monomer units is in the range of from about 0.0 mole% to about 5.0 mole%, preferably from 0.25 mole% to about 5 mole%, although higher amounts can be included as needed to obtain the desired results. Diethylene glycol can be made as a byproduct of the polymerization process, or it can be added directly to the composition to help accurately regulate the amount of diethylene glycol monomer units that are in the polymer. In preferred embodiments, portions of isosorbide are present in the polymer in amounts ranging from about 0.10 mole% to about 12 mole%, preferably from about 0.25 mole% to about 10.0 mole%, more preferably about 0.5. moles% to about 6.0 moles% and much more preferably from 1.0 moles% to 5.0 moles%, although larger amounts may be included as necessary to obtain the desired results. The isosorbide is most preferably present in the range of 1 mol% to 3 mol%. One or more monomer units of another diol may optionally be included in amounts up to a total of about 5.0 mole%, preferably less than 3 mole% and much more preferably less than 2 mole%. The amount of other diols included, however, may be greater than necessary to obtain the desired results. Examples of the optional units or other diol units include aliphatic alkylene glycols having 3-12 carbon atoms and having the empirical formula H0-CnH2n-0H, where n is an integer of 3-12, including branched diols such as 2,2-dimethyl-1,3-propanediol; cis or trans-1,4-cyclohexanedimethanol and mixtures of cis and trans isomers; triethylene glycol; 2, 2-bis [4- (2-hydroxyethoxy) phenyl] propane; 1, 1-bis [4- (2-hydroxyethoxy) phenyl] cydohexane; 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene; 1, 4: 3, 6-dianhydromanitol; 1,4: 3,6-dianhydroiditol; and 1,4-anhydroerythritol.

The terephthaloyl moieties in the polyester can vary from 25-50 mole%, preferably from about 35-50 mole% and more preferably 40-50 mole% and much more preferably 48-50 mole%, although They may include larger quantities as necessary to obtain the desired results. If desired, other aromatic diacid portions in the polymer can include, for example, those derived from isophthalic acid, 2,5-furanedicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2, 7-acid. Naphthalenedicarboxylic acid, 4'-benzoic acid, at combined levels of up to about 15 mol%, preferably less than 10 mol% and more preferably between about 0.01 mol% and 5 mol%, more preferably, less than 2 moles%, although larger quantities may be included as necessary to obtain the desired results. It is preferable that equimolar amounts of the diacid monomer units and the diol monomer units are present in the polymer in order to obtain a high molecular weight and a high inherent viscosity, which provides a lower shrinkage rate and a lower temperature. Greater vitreous transition (Tg) than, for example, poly (ethylene terephthalate). The polyester formed has an inherent viscosity, which is an indicator of molecular weight, of at least about 35 dl / g, measured in a 1% (w / v) solution of the polymer in o-chlorophenol at a temperature of 25 °. C. Preferably, the inherent viscosity is at least about 0.45 dl / g, more preferably greater than 0. 5 dl / g, and even more preferably greater than 0.6 dl / g, and much more preferably higher of 0.7 dl / g. The inherent viscosity can be adjusted to obtain the desired characteristics based on the composition of the polymer and the formation method. The molecular weight is not usually measured directly. Instead, the inherent viscosity of the polymer in solution or the molten viscosity is used as an indicator of molecular weight. For the present polymers, the inherent viscosity is measured by the method previously described, with a molecular weight corresponding to an inherent viscosity of about 0.35 dl / g or greater. Higher molecular weights corresponding to inherent viscosity of at least about 0.50 dl / g are preferred, and molecular weights corresponding to inherent viscosities of about 0.7 dl / g and above are desirable for many uses. Generally, the ratio of inherent viscosity / molecular weight can be adjusted to the linear equation: log (IV) = 0.586 x log (Mw) -2.9672 Inherent viscosities are a better indicator of molecular weight for sample comparisons and are used as the molecular weight indicator. The polyesters used to make the containers of the invention can be manufactured by any of several methods. The product compositions vary to some extent depending on the method used, particularly on the amount of diethylene glycol residues that are present in the polymer. These methods include the reaction of the diol monomers with the acid chlorides of terephthalic acid and any other acid that may be present. The reaction of terephthaloyl dichloride with isosorbide and ethylene glycol is easily carried out by combining the monomers in a solvent (for example toluene) in the presence of a base, such as pyridine, which neutralizes the HCl as it is produced. This procedure is described in R. Storbeck et al., J. Appl. Polymer Science. Vol. 59, pp. 1199-1202 (1996). Other well-known variations can also be used using terephthaloyl dichloride (for example interfacial polymerization) or simply by stirring the monomers together while heating, preferably in the presence of a base).

When the polymer is made using acid chlorides, the ratio of monomer units in the polymer of the product is about the same as the ratio of monomers that react. Therefore, the ratio of monomers charged to the reactor is approximately the same as the desired ratio in the product. A stoichiometric equivalent of the diol and the diacid will generally be used to obtain a high molecular weight polymer suitable for packaging (eg, an inherent viscosity of at least about 0.50-0.60 dl / g). The polymers can also be made by a melt polymerization process, in which the acid component is terephthalic acid or dimethyl terephthalate, and which also includes the free acid or the dimethyl ester of any other aromatic diacid which can be included in the composition polymeric The diacids or dimethyl esters are heated with the diols (ethylene glycol, isosorbide, optional diols) in the presence of a catalyst at a sufficiently high temperature so that the monomers combine to form esters and diesters, then the oligomers and finally the polymers. The polymer product at the end of the polymerization process is a molten polymer. The diol monomers (for example ethylene glycol and isosorbide) are volatile and are distilled from the reactor as the polymerization progresses. Therefore, an excess of these diols is generally charged to the reactor to obtain the desired polymer, and the amounts are adjusted according to the characteristics of the polymerization vessel (ie, characteristics such as the efficiency of the distillation columns and the monomer recovery and recycling efficiency). Such modifications in the amounts of monomers and the like according to the characteristics of a reactor are easily realized by those skilled in the art. Melt polymerization processes using dihydroxyethyl esters of terephthalic acid, such as bis (2-hydroxyethyl) terephthalate, are also known and can be modified to make the polymers described herein. The melt polymerization process is the preferred method for making the polymer and is described in detail in the commonly assigned, co-pending, U.S. Application No. 09 / 064,844, Attorney's File No. 03258-001 filed on the same date. that the present, and incorporated aguí as a reference. The process of melt polymerization using dimethyl terephthalate and terephthalic acid is also summarized in the following.

Process of dimethyl terephthalate In this process, which is carried out in two stages, terephthalic acid and the optional diacid monomers are used, if present, such as its dimethyl ester derivatives. The diols (for example ethylene glycol and isosorbide) are mixed with the dimethyl ester of the aromatic diacid (for example dimethyl terephthalate) in the presence of an ester exchange catalyst, which causes an exchange of ethylene glycol of the methyl group of the esters of dimethyl through a transesterification reaction. This results in the formation of methanol, which is distilled off from the reaction flask, and bis (2-hydroxyethyl) terephthalate due to the reaction stoichiometry, a little more than two moles of ethylene glycol are desirably added as reactants for the ester exchange reaction. The catalysts carrying out the ester exchange include salts (usually acetates) of the following metals: Li, Ca, g, Mn, Zn, Pb and combinations thereof, Ti (0R) 4, wherein R is a group some have 2-12 carbon atoms, and PbO. The catalyst components are generally included in an amount of about 10 ppm to about 100 ppm. Preferred catalysts for ester exchange include Mn (0Ac) 2 / Co (0Ac) 2, and Zn (0A) 2, wherein OAc is the abbreviation for acetate and combinations thereof. The polycondensation catalyst which is necessary for the second step of the reaction, preferably Sb (III) or Ge (IV) oxide, can be added now or at the beginning of the polycondensation step. A catalyst that has been used particularly successfully for ester exchange is based on salts of Mn (II) and Co (II) at levels of about 50 to about 100 ppm each. These are used in the form of Mn (II) acetate tetrahydrate and Co (II) acetate tetrahydrate, although other salts of the same metals can also be used. The ester exchange is carried out approximately by heating and stirring the reagent mixture under an inert atmosphere (eg nitrogen) at atmospheric pressure from room temperature to a temperature high enough to introduce ester exchange (approximately 150 °). C). The methanol is formed as a by-product and is distilled off from the reactor. The reaction is gradually heated to about 250 ° C until the methanol production is stopped. The completion of methanol production can be recognized by a decrease in the upper temperature of the reaction vessel. A sticking amount of an additive having a boiling point of 170-240 ° C can be added to the ester exchange to aid in heat transfer within the reaction medium and to help retain volatile components in the container that can Sublimate in the fill column. The additive must be inert and must not react with alcohols or dimethyl terephthalate at temperatures below 300 ° C. Preferably, the additive has a boiling point greater than 170 ° C, more preferably within the range of 170 ° C to 240 ° C, and is used in an amount between about 0.05 and 10% by weight, more preferably between about 0.25 and 1% by weight of the reaction mixture. A preferred additive is tetrahydronaphthalene. Other examples include diphenylether, diphenylsulphan and benzophenone. Other such solvents are described in U.S. Patent 4,294,956, the content of which is incorporated herein by reference. The second stage of the reaction is initiated by adding a polycondensation catalyst (if not present in advance) and a sequestering agent for the transesterification catalyst. Polyphosphoric acid is an example of a sequestering agent and is preferred. It is usually added in an amount of about 10 to about 100 ppm phosphorus per g of dimethyl terephthalate. Examples of preferred polycondensation catalysts are antimony (III) oxide and germanium (IV) oxide, which can be used at levels of about 100 to about 400 ppm. Germanium (IV) oxide is the most preferred polycondensation catalyst. The polycondensation reaction is typically carried out at a temperature from about 250 ° C to 285 ° C. During this time, ethylene glycol is distilled off from the reaction due to the condensation of bis (2-hydroxyethyl) terephthalate to form a polymer and a by-product of ethylene glycol, which is collected as a distillate. The polycondensation reaction described above is preferably carried out under vacuum, which can be applied while the reactor is heated to the polycondensation reaction temperature or after the Sb (III) oxide or Ge oxide has been added. (IV) and polyphosphoric acid. Alternatively, vacuum may be applied after the polycondensation reaction temperature reaches 280 ° C-285 ° C. In any case, the reaction is accelerated by the application of vacuum. Heating under vacuum continues until the molten polymer reaches the desired molecular weight, usually recognized by an increase in the viscosity of function at a predetermined level. This is observed as an increase in the torque required for the agitation motor to maintain agitation at constant rpm. An inherent viscosity of at least 0.5 dl / g and generally up to about 0.65 dl / g or greater, can be obtained by this melt polymerization process without additional efforts being made to increase the molecular weight. For a certain composition, the molecular weight ranges can be further increased by solid state polymerization, described below.

Process of terephthalic acid The process of terephthalic acid is similar to the process of dimethyl terephthalate, except that the initial esterification reaction leading to bis (2-hydroxyethyl terephthalate) and to the other low molecular weight esters is carried out at a slightly elevated pressure ( autogenous pressure of approximately 172 to 345 kPa (25 to 50 psig)). Instead of a two-fold excess of the diols, a more sticky excess (from about 10% to about 60%) of the diols (ethylene glycol, isosorbide and other diols, if any) is used. The intermediate esterification product is a mixture of oligomers, since sufficient diol is not present to generate a diester of terephthalic acid. The catalysts are also different. It is not necessary to add catalysts in the esterification reaction. A polycondensation catalyst (for example salts of Sb (III), Ge (IV), or Ti (IV)) is still necessary to obtain a high molecular weight polymer. The catalyst that is needed to obtain a high molecular weight can be added after the esterification reaction, or it can be conveniently charged with the reactants at the start of the reaction. Catalysts which are useful for making a high molecular weight polymer directly from terephthalic acid and the diols include acetate or other salts of Sb (III) alkanoate, Sb (HI) and Ge (IV) oxides, and Ti (0R) 4 (wherein R is an alkyl group having 2 to 12 carbon atoms). The solubilized glycol oxides of these metal salts can also be used. Co (II) salts may also be present. The use of this and other catalysts in the preparation of polyesters is well known in the art. The reaction can be carried out in discrete stages, but this is not necessary. In large-scale practice, it can be carried out in stages as the reactants and intermediates are pumped from the reactor to the reactor at increasing temperatures. In a batch process, the reactants and catalyst can be charged to the reactor at room temperature and then gradually heated to about 285 ° C as the polymer is processed. The pressure is vented in the range of about 200 ° C to about 250 ° C, and then vacuum is desirably applied. The esterification to form the esters of bis (2-hydroxyethyl) terephthalate and the oligomers is carried out at elevated temperatures (between room temperature and about 220 ° C to 265 ° C under autogenous pressure), and the polymer is processed at temperatures in the range of about 275 ° C to about 285 ° C under high vacuum (less than 10 Torr, preferably less than 1 Torr). The vacuum is necessary to remove residual ethylene glycol and water vapor from the reaction to increase molecular weight. A polymer having an inherent viscosity of at least 0.5 dl / g and generally up to about 0.65 dl / g can be obtained by a direct polymerization process, without subsequent polymerization in the solid state. The development of the polymerization can be followed by melt viscosity, which is readily observed by the torque that is needed to maintain the stirring of the polymer melt.

Solid state polymerization The polymers can be made by melt condensation processes described above having an inherent viscosity of at least about 0.5 dl / g, and often as high as about 0.65 dl / g or greater, without further treatment. For packaging, a polymer having an inherent viscosity of at least about 0.6 dl / g, and preferably about 0.7 dl / g, to obtain packages having good tensile properties is generally desirable. This is especially true for bottles with soft drinks that must withstand internal pressure of carbon dioxide. The ethylene glycol compositions, isosorbide and terephthalic acid having isosorbide in an amount of about 0.25% to about 10% on a mole basis can have their molecular weight further increased by solid state polymerization. The product made by melt polymerization, after extrusion, cooling and granulation, is essentially non-crystalline. The material can be made of semicrystalline material by heating at a temperature in the range of about 115 ° C to about 140 ° C for an extended period of time (about 2 to about 12 hours). This induces crystallization so that the product can be heated to a much higher temperature to increase the molecular weight. The process works best for low levels of isosorbide, from about 0.25 mol% to about 3 mol%, because the polyester crystallizes more easily with low levels of isosorbide. The polymer made by other methods can also crystallize under these same conditions. The polymer can also be crystallized prior to polymerization in the solid state by treatment with a relatively poor solvent for polyesters, such as acetone, which induces crystallization. Solvent-induced crystallization followed by solid state polymerization is known for polyesters and is described in U.S. Patent Nos. 5,164,478 and 3,684,766, which are incorporated herein by reference. The crystallized polymer is subjected to polymerization in the solid state by placing the granulated or powdered polymer in a stream of inert gas, usually nitrogen, or under a vacuum of 1 Torr, at an elevated temperature, above about 140 ° C, but below of the melting temperature, for a period of about 2 to about 16 hours. The solid state polymerization is preferably carried out at temperatures from about 190 ° C to about 210 ° C. Excellent results have been obtained by heating the polymer from about 195 ° to about 198 ° C for about 10 hours, which results in an inherent viscosity increase of about 0.8 dl / g or more.

Method for making packaging The packages described herein may be made by any method known in the art, such as extrusion, injection molding, blow molding and injection molding, rotational molding, sheet thermoforming and stretch and blow molding. In the present invention, the preferred method for molding a package is stretch casting, which is generally used in the production of poly (ethylene terephthalate) (PET) containers, such as bottles. In this case, you can use any of the cold parison methods, in which a preformed parison is taken (usually made by injection molding) out of the mold and then subjected to blow-molding and stretching in a separate step. The hot parison method is known in the art and can be used, wherein the hot parison is immediately subjected to blow molding and stretching in the same form without complete cooling after injection molding to make the parison. The temperature of the parison is from about 100 ° C to about 160 ° C, and preferably from about 110 ° C to about 150 ° C. The blow-and-stretch molding is preferably carried out at a mold temperature from about 90 ° C to about 150 ° C, and still more preferably from about 100 ° C to about 135 ° C. The containers of the invention can have any desirable shape, and particularly include narrow-mouth bottles and wide-mouth jars having threaded tops and a volume of about 450 ml to about 3 liters, although larger and larger containers can be made. . The containers can be used in standard cold filling applications and surprisingly, they can be used in hot fill applications, even at the lowest levels of inclusion of isosorbide (1%) where the effect of the isosorbide content on the temperature Vitrea transition is very small. The hot filled bottles are filled with hot liquids at temperatures greater than about 60 ° C, preferably up to at least about 88 ° C, and ideally at temperatures above about 88 ° C. The containers of the invention can withstand hot filling process temperatures without any annealing step, unlike PET containers, although the annealing step can be carried out if desired. The containers of the invention are suitable for food and beverages and other solids and liquids. The containers are normally almost colorless and transparent, but can be modified to have color or to be opaque, instead of being transparent, if desired, by adding dyes or dyes, or by causing the crystallization of the polymer what results in a condition opaque Additional additives such as oxidation stabilizers, ultraviolet light absorbing substances, antistatic agents and flame retardants may be added if desired, depending on the specific end use of the package. The packages of the present invention can also be made with polyesters described in co-pending application 09 / 064,720 [Attorney's file No. 032358-008] and the polyester combinations described in co-pending application 09 / 064,826 [Attorney's file No. 032358 -005] the content of each of which is incorporated herein by reference.

Examples The molecular weights of the polymers are estimated based on the inherent viscosity (I.V.), which is measured for a 1% (w / v) solution of the polymer in o-chlorophenol at a temperature of 25 ° C. Levels of catalyst components are expressed as ppm, based on a comparison of the weight of the metal with the weight of either dimethyl terephthalate or terephthalic acid, depending on which monomer is used.

EXAMPLE 1 The following polymerization reagents are added to a maximum capacity of 378 liters (100 gallons) of a stainless steel polymerization reactor, to which is placed a reflux column cooled with stainless steel water with a radius of 15 cm (6") packed with stainless steel rings, a stainless steel blade type stirrer, a water cooled condenser and a derivation: 197 kg of dimethyl terephthalate, 5.12 kg of isosorbide and 135 kg of ethylene glycol, which corresponds to a molar ratio of 1: 0.0346: 2.00 The catalyst is also charged and consists of 72.1 g of Mn (II) acetate tetrahydrate, 54.1 g of Co (II) acetate tetrahydrate and 88.5 g of Sb (III) oxide This corresponds to 82 ppm of manganese (weight of the metal as a fraction of the weight of dimethyl terephthalate), 65 ppm of cobalt and 375 ppm antimony The stirred reactor (50 rpm) is purged with a stream of nitrogen while increasing the temperature to 250 ° C, gradually over a period of 4 hours The reactor is lined and uses an oil cycle system hot controlled temperature as a means of heating The methanol production is started and the methanol is continuously collected after the reaction is heated above about 150 ° C. Noting the time when the temperature decreases in the upper part of the packed reflux column, it is possible to determine the end of the methanol production, which indicates the completion of the first stage of the reaction, which is the transesterification of the diols and dimethyl terephthalate. At this point 82 ppm of phosphorus are added in the form of a solution of polyphosphoric acid in ethylene glycol. In this case, 153 ml of the solution is used, which has a concentration of 0.80% by weight of phosphorus. Also at this time, the nitrogen purge is stopped while heating is continued. The reaction is heated to 285 ° C for a period of about 2 hours. Then vacuum is gradually applied using a vacuum pump with a multiple vacuum with a 20 horsepower fan. Obtaining a complete vacuum, preferably less than 1 Torr, reguires approximately 1 hour. During this time, ethylene glycol is removed by distillation, and a low molecular weight polymer is formed. The molten polymer is heated under vacuum at 285 ° C, for about 2 hours, until the polymer has a sufficient melt viscosity, determined by an increase in the torque of the agitator. When sufficient melt viscosity is obtained, the polymerization is stopped and the polymer is emptied from the reactor through a heated trogue at the bottom. The molten polymer arises as a chain that is cooled in a cold water channel and then cut into granules. The polymer granules are dried overnight in a rotating drum heated to 120 ° C. The inherent viscosity of the solution (I.V.) of the material is 0.64 dl / g. The granulated polymer is loaded in a drum dryer and heated under a stream of nitrogen at 185 ° C for a period of 4 hours. It is maintained at that temperature for another 6 hours, which allows the polymer to partially crystallize. After this treatment, vacuum is applied to the drum dryer, obtaining a vacuum of less than 1 mm Hg. The heating continues until a maximum temperature of 213 ° C, which is maintained for a total of about 5 hours. This accomplishes a polymerization in the solid state and allows the molecular weight to be significantly increased, judging by an increase in the inherent viscosity (I.V.) of the polymer solution in ortho-chlorophenol at about 0.7 dl / g. The composition of the monomer unit of the polymer, determined by proton NMR, is about 1% isosorbide, 49% ethylene glycol, 0.7% diethylene glycol, and 50% terephthalic acid, expressed as moles% of the polymer. It is notable that the amount of isosorbide in the polymer is about half the amount that has been charged, when compared to the amount of terephthalic acid. The isosorbide that has not reacted is found in the distillates, especially in ethylene glycol. The amount of isosorbide in the polymer by this process therefore depends very much on the efficiency of the distillation or other separation methods that are used in the process. A person who implements the invention can easily establish the specific details of the process, according to the characteristics of the reactor, distillation columns and the like.

EXAMPLE 2 A second polymer with a higher isosorbide content is prepared in a manner analogous to Example 1, except that the amount of charged isosorbide is 17.8 kg and the amount of Mn (II) acetate tetrahydrate catalyst used is 79.2 g, which corresponds to 90 ppm of Mn (II), calculated on the same basis as in the previous example. The transesterification and polycondensation is carried out as described above. The finished polymer is granulated, crystallized and polymerized in the solid state by the same method as in the previous example. In the present case, a change in the viscosity of the solution occurs before the polymerization in solid state already indicated. The composition of the monomer unit of this polymer determined by proton NMR shows the desired increase in the isosorbide content and comprises the following monomers: approximately 2.6% isosorbide, 46.7% ethylene glycol, 0.7% diethylene glycol and 50% acid terephthalic, all expressed as moles% of the polymer.

EXAMPLE 3 The polymers of Examples 1 and 2 are made in 640 ml jars in a Nissei ASB100DH commercial single blow molding and stretch molding unit using a single step stretch blow molding process and using a 132.5 mm rod. for the stretched. The polymer is injection molded at a melting temperature of about 270 ° C to make a preform, which is then subjected to a stretch casting and blow molding process at 102 ° C in the same type without complete cooling. The conditions of the stretch casting and blow molding process are previously optimized for PET and, therefore, have been less than optimal for the polymers of Examples 1 and 2 that were molded under those conditions.

Analytical and test data The analytical data regarding the thermal properties and compositions of monomer units of the polymers are presented in Table 1. The monomer unit compositions of the polymers of Examples 1 and 2 are measured by NMR. The amounts of the monomers in the NMR analyzes in Examples 1 and 2 are normalized to 100%. The PET control is a commercial bottle resin having the following composition: 48.3 mole% terephthalic acid, 1.7 mole% isophthalic acid, 1.25 mole% diethylene glycol, 48.75 mole% ethylene glycol. The composition measured by NMR is 48.7 mole% terephthalic acid, 1.3 mole% isophthalic acid, 48.5 mole% ethylene glycol and 1.5 mole% diethylene glycol. The thermal properties are measured by differential scanning calorimetry (DSC) at a heating rate of 10 ° C / min. The thermal properties that are measured include vitreous transition temperature, cold crystallization temperature during heating, melting temperature, crystallization temperature in cooling and heat of crystallization. Table 2 summarizes the molding conditions for the preparation of the preforms. In Tables 3 and 4 the data are presented in the operation of hot filling of the jars.

In Table 3, the jars are filled with a hot liquid (water or corn syrup) at a temperature shown in the first column and then cooled either quickly or slowly, as established in the first column. In the rapid cooling, the jars are allowed to cool to air at room temperature. The shrinkages, measured as% decrease in volume, are measured for the jars made of the polymers of Examples 1 and 2. The jars made of PET control polymers are deformed in all the experiments where they were filled in. hot. Therefore, no data are presented for the jars made of PET control polymers. The jars made of the polymers of Examples 1 and 2 for the most part do not deform, but show a decreased volume due to a smaller shrinkage variation from 1% to approximately 10% when filled at temperatures above 92 ° C. Table 4 presents data for the same hot-fill experiments as in Example 3. The data in Table 4 is shrinkage of the diameter of the neck finish (the part of the neck above the threads) after filling the jar with hot and cool the jar. A shrinkage of less than 2% of the neck is desirable. The blow molded and stretched jars are then tested and have the following wall thicknesses:PET control Wall thickness of the bottle; 0.669 mm Thickness of the neck wall: 2.051 mm Example 1 Wall thickness of the bottle: 0.580 mm Wall thickness near the neck: 2.105 mm Example 2 Thickness of wall of the bottle: 0.597 mm Thickness of wall near the neck: 2.169 mm EXAMPLE 4 The polymer of Example 2 is dried overnight in a vacuum dryer at 132.2 ° C (270 ° F). After drying, the moisture content is approximately 50 ppm. The dry polymer is injection molded into generic style 50.5 g preforms with a standard 43 mm VHS finish. The preforms are placed in a blow-molding and re-heating stretch of the Sidel SBO-2/3 where they are heated to 148 ° C and blown in 1-liter, heat-set generic containers. The mold temperature is set to 132.2 ° C (270 ° F) with a base temperature of 71.1 ° C (160 ° F). These mold conditions are the standard conditions used to make PET containers for hot filling. Several containers are then molded at a rate of 800 bottles per hour with an idle time in the mold of about 3 seconds. The mold temperature is subsequently reduced to 93.3 ° C (200 ° F), and several additional bottles are made again to test the hot fill. This second set of mold conditions is not suitable for the production of a PET bottle that can be hot filled. The resulting bottles are first measured in terms of the diameter in four positions for the height of the bottle and for the overfill volume of the bottle. The bottles are then tested for hot fill operation by filling them with hot water at temperatures ranging from 85 ° C (185 ° F) to 96.1 ° C (205 ° F). After the stoppered bottles are cooled, the shrinkage of the bottle diameters in the same four positions on the bottles is measured, and the changes in the height of the bottle and the volume are measured to determine the percent shrinkage and determine whether the bottles have been distorted. The shrinkage for hot filled containers should preferably be less than 3%. The change in volume percent data is summarized in Table 5 for bottles obtained using a 132 ° C (270 ° F) mold, and in Table 6 for bottles obtained from a 93.3 ° C (200 °) mold. F). The comparative data for volume change in percent are also obtained for resins in standard PET bottles molded essentially under the same conditions, with a mold temperature of 132.2 ° C (270 ° F). 20 samples of PET bottles are tested at increasing temperatures from 85.3 ° C (185.5 ° F) to 90.6 ° C (195 ° F), and the results of the four representative tests are shown in Table 7. see in the data of Tables 5 to 7 that bottles containing isosorbide work better than PET bottles, even if PET bottles have been subjected to a "heat setting" to improve their operation under hot filling conditions. When comparing Tables 5 and 6, it can also be seen that the heat setting step appears to further improve the operation of polyester bottles containing isosorbide. It should be understood that the embodiments described in the foregoing are illustrative only and modifications may occur to one skilled in the art. Accordingly, the invention is not considered limited by the modalities described above.

TABLE 1. ANALYTICAL DATA TABLE 2. CONDITIONS OF OPERATION OF THE EXTRUSOR TABLE 3.% SHRINK IN VOLUME OF JARS OF 460 ml (AFTER FILLING WITH HOT LIQUID) TABLE 4.% NON-SHRINK FINISHING OF JARS NECK OF 460 ml (AFTER FILLING WITH HOT LIQUID) Table 5. Hot-filled bottle operation of the polymer of Example 2 (mold at 132 ° C (270 ° F)) Table 6. Hot-filled bottle operation of the polymer of Example 2 (mold at 93 ° C (200 ° F)) Table 7. Comparative PET bottle operation (mold of 132 ° C (270 ° F)) It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Claims (36)

CLAIMS Having described the invention as above, it is claimed as property or content in the following claims:

1. A package made of a polyester, wherein the polyester comprises portions of terephthaloyl; optionally one or more portions of aromatic diacid; portions of ethylene glycol; portions of isosorbide; and optionally one or more additional diol portions, wherein the polyester has an inherent viscosity of at least about 0.35 dl / g when measured as an i% (w / v) solution of the polyester in o-chlorophenol at a temperature of 25 ° C.

2. The package according to claim 1, characterized in that the terephthaloyl moieties are derived from terephthalic acid or dimethyl terephthalate.

3. The package according to claim 1, characterized in that the polyester further comprises portions of diethylene glycol.

4. The container according to claim 1, characterized in that one or more additional diol portions are derived from aliphatic aliphatic glycols or branched aliphatic glycols having 3-12 carbon atoms and having the empirical formula H0-CnH2n-0H wherein n it is a number of 3-12; cis or trans-1,4-cyclohexanedimethanol or mixtures thereof; triethylene glycol; 2, 2 -bis [4 - (2-hydroxyethoxy) f-enyl] propane; 1, 1-bis [4 - (2-hydroxyethoxy) phenyl] cyclohexane; 9, 9-bis [4- (2-hydroxyethoxy) phenyl] -fluorene; 1.4: 3, 6-dianhydromanitol; 1,4: 3,6-dianhydroiditol; or 1,4-anhydroerythritol.

5. The container according to claim 4, characterized by one or more additional diol portions are derived from cis-1,4-cyclohexanedimethanol, trans-1,4-cyclohexanedimethanol or mixtures thereof.

6. The container according to claim 1, characterized in that the optional or additional aromatic diacid portions are derived from isophthalic acid, 2,5-furanedicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, acid 2, 7-naphthalenedicarboxylic acid or 4,4'-benzoic acid.

7. The container according to claim 6, characterized in that one or more aromatic diacid portions are derived from isophthalic acid, 2,6-naphthanedicarboxylic acid, 4,4'-benzoic acid or mixtures thereof.

8. The container according to claim 1, characterized in that the inherent viscosity is at least about 0.50 dl / g.

9. The container according to claim 8, characterized in that the inherent viscosity is at least about 0.70 dl / g.

10. The container according to claim 1, characterized in that the terephthaloyl moieties are present in an amount from about 40 to about 50 mole% of the polyester, the other aromatic diacid portions are present in an amount of up to about 10.0 mole% of the polyester, the ethylene glycol moieties are present in an amount from about 28 to about 49.75 mole% of the polyester, the isosorbide moieties are present in an amount from about 0.25 to about 12.0 mole% of the polyester, and the other diol moieties are present in an amount of up to about 10.0 moles% of the polyester.

11. The package according to claim 10, characterized in that the other diol portions are portions of diethylene glycol in an amount of up to about 5.0 mole% of the polyester.

12. The package according to claim 1, characterized in that the package can be filled with a temperature at a temperature of at least about 60 ° C.

13. The package according to claim 12, characterized by having a decrease in volume of less than about 3%.

14. The container according to claim 12, characterized in that the container can be filled with a temperature of at least about 88 ° C.

15. The container according to claim 14, characterized in that it has a decrease in volume of less than about 3%.

16. The container according to claim 1, characterized by the container is a narrow neck bottle or a wide mouth jar.

17. The container according to claim 1, characterized in that the isosorbide portions are present in an amount from about 1 mole% to about 6 mole% of the polyester.

18. The container according to claim 17, characterized in that the isosorbide portions are present in an amount from about 1 mole% to about 3 mole% of the polyester.

19. A method for making a package, characterized in that the package comprises a polyester, the method is characterized by comprising: a) forming the polyester; and b) prepare the container; wherein the polyester comprises portions of terephthaloyl; and, optionally, other aromatic diacid portions; portions of ethylene glycol, portions of isosorbide; and optionally, other diol portions; wherein the polyester has an inherent viscosity of at least about 0. 35 dl / g, when measured as a 1% (weight / volume) solution of the polyester in o-chlorophenol at a temperature of 25 ° C.

20. The method according to claim 19, characterized in that the formation of the polyester comprises: (a) combining in a reactor a monomer comprising a portion of terephthaloyl; optionally one or more additional monomers containing an aromatic diacid portion; a monomer comprising a portion of ethylene glycol; a monomer comprising a iosorbide portion; and optionally, one or more additional monomers comprising a portion of diol with a condensation catalyst suitable for condensing aromatic diacids and glycols; and (b) heating the monomers and the catalyst at a temperature sufficient to polymerize the monomers in a polyester polymer having at least a portion of terephthaloyl, a portion of ethylene glycol and an isosorbide portion, wherein the heating is continued during a time sufficient to produce a polyester having an inherent viscosity of at least about 0.35 dl / g when measured as a 1% (w / v) solution of the polyester in o-chlorophenol at a temperature of 25 ° C.

21. The method according to claim 20, characterized in that the heating of the monomers also includes agitation of the monomers with the concurrent removal of by-products by distillation or evaporation, or both.

22. The method according to claim 20, characterized in that the monomer comprising a terephthaloyl moiety is terephthalic acid.

23. The method according to claim 22, characterized in that the water and monomer that has not reacted are removed while the monomers polymerize.

24. The method according to claim 20, characterized in that the monomer comprising a terephthaloyl moiety is dimethyl terephthalate.

25. The method according to claim 24, characterized in that the unreacted methanol and monomer are removed while the monomers polymerize.

26. The method according to claim 19, characterized in that one or more optional additional diol portions are derived from aliphatic aliphatic glycols or branched aliphatic glycols having 3-12 carbon atoms and having the empirical formula H0-CnH2n-0H, in where n is a number of 3-12; cis or trans-1,4-cyclohexanedimethanol or mixtures thereof; triethylene glycol; 2, 2-bis [4- (2-hydroxyethoxy) phenyl] propane; 1, 1-bis [4- (2-hydroxyethoxy) phenyl] cydohexane; 9,9 -bis [4- (2-hydroxyethoxy) phenyl] -fluorene.

27. The method according to claim 19, characterized in that optional additional aromatic diacid portions are derived from isophthalic acid, 2,5-furandicarboxylic acid, 2,5-thiophenedicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-acid. -nandicarboxylic acid or 4, 4'-benzoic acid.

28. The method according to claim 19, characterized in that the terephthaloyl moieties are present in an amount of about 40 to 50 mole% of the polyester, one or more optional additional aromatic diacid moieties are present in an amount of up to about 10 mole%. of the polyester, the ethylene glycol moieties are present in an amount of about 28 to 49.75 mole% polyester, the isosorbide moieties are present in an amount of about 0.25 to 20.0 mole% polyester, and one or more additional diol moieties are present in an amount of up to about 10.0 mole% of the polyester.

29. The method according to claim 28, characterized in that one or more additional diol portions comprise portions of diethylene glycol in an amount of up to about 5.0 mole% of the polyester.

30. The method according to claim 20, characterized by further comprising increasing the molecular weight of the polyester by polymerization in the solid state.

31. The method according to claim 30, characterized in that the solid state polymerization comprises: (a) crystallizing the polyester by heating the polyester at a temperature in the range of about 115 ° C to about 140 ° C; and (b) heating the polyester under vacuum or in an inert gas stream at an elevated temperature above 140 ° C but below the melting temperature of the polyester to provide a polyester having an increased inherent viscosity.

32. The method according to claim 31, characterized in that the heating step (b) is carried out at a temperature of about 195 ° to 198 ° C for about 10 hours.

33. The method according to claim 31, characterized in that the increased inherent viscosity is at least about 0.65 dl / g.

34. The method according to claim 19, characterized in that the preparation of the package comprises extrusion, injection molding, stretch molding and blow molding, injection molding and blow molding or thermoforming the polyester to form the package.

35. The method according to claim 34, characterized in that the preparation of the package comprises stretching and blowing molding of the package.

36. The method according to claim 19, characterized by further comprising filling the package, wherein the package is hot filled or cold filled.