MULTI-TRAINED POLYESTER ARTICLES CONTAINING A
WASTE OF FENILENDI (ACETIC ACID) AND THAT HAVE GOOD BARRIER TO GAS PERMEATION
DESCRIPTION OF THE INVENTION This application claims the benefit of the
Provisional Applications of the United States 60 / 089,221, filed on June 15, 1998, 60 / 089,220, filed on June 15, 1998 and 60 / 089,391 filed on June 15, 1998. The invention relates to multi-layered structures. Specifically, the invention relates to multi-layered structures such as containers wherein the barrier layer comprises a polyester or a copolyester containing a residue of phenylendi (oxyacetic acid), or a mixture comprising a polyester or copolyester of a phenylene residue ( oxyacetic). U.S. Patents 5,688,572, 5,221,507, 5,049,345 and 4,923,723 describe multi-layered constructions containing a barrier layer. UA multi-layered construction involves ethylene vinyl alcohol copolymers (also with reference to EVOH), and the other multi-layered construction involves nylon called MXD-6, prepared from meta-xylylene diamine and adipic acid. In multi-layered construction, as a minimum, the
m t ~ m, r * bottles employing these barrier layers have at least one inner or outer layer of poly (ethylene terephthalate) with an inner layer of the chosen barrier material. Both EVOH and MXD-6 constructions, however, have serious potential disadvantages. For the EVOH construction, the barrier is a pronounced function of the relative humidity of the storage environment with a very hot, humid environment that degrades the barrier behavior by more than an order of magnitude. In addition, only a very small amount of EVOH contamination in the recirculation stream of poly (ethylene terephthalate) can have very adverse effects. The two polymers are totally incompatible and form a mixture of two phases even in the presence of less than 1% by weight of EVOH. This causes haze if the material is used for containers such as bottles and causes tremendous forming problems if the recovered poly (ethylene terephthalate) is used for fiber shaping. It is very difficult to remove the EVOH to the required level from the recirculation stream of poly (ethylene terephthalate). MXD-6 nylon has similar problems although not to the same degree as EVOH. However, XD-6 imparts an undesirable yellow color to polyesters at very low concentrations. In methanolysis recirculation processes nylsn MXD-6 contaminates raw materials leaving the process with a small amount of diamine, leading to recirculated materials to be unsuitable for packaging applications. While the aforesaid patents and those referred to herein describe various technologies for the production of multi-layered structures having a barrier layer, they do not contemplate the use of multi-layered structures having a barrier layer comprised of a polyester or copolyester containing a phenylendi residue (oxyacetic acid), or a mixture comprising a polyester or copolyester of a phenylenedi residue (oxyacetic acid), which exhibits a longer half-life, design freedom, improved barrier properties and it is recyclable. The present invention provides multi-layered structures containing at least one barrier layer comprising a residue of phenylendi (oxyacetic acid). In one embodiment, the invention provides a multi-layered structure comprising: (a) a first layer comprising a polyester or copolyester of poly (ethylene terephthalate); Y
(b) a barrier layer comprising a residue of phenylendi (oxyacetic acid), wherein the barrier layer is adjacent to the first polyester or copolyester layer. In another embodiment, the invention provides a multi-layered structure comprising: (a) a first layer comprising a polyester or copolyester of poly (ethylene terephthalate); (b) a first barrier layer comprising a residue of phenylendi (oxyacetic acid); and (c) a second layer comprising a polyester or copolyester of poly (ethylene terephthalate), wherein the first barrier layer is disposed intermediate to the first layer of polyester or copolyester and the second layer of polyester or copolyester. In another embodiment, the invention provides a multi-layered structure comprising: (a) a first layer comprising a polyester or copolyester of poly (ethylene terephthalate); (b) a first barrier layer comprising a residue of phenylendi (oxyacetic acid); (c) a second layer comprising a polyester or copolyester of poly (ethylene terephthalate); (d) a second barrier layer comprising a phenylendi residue (oxyacetic acid); and (e) a third layer comprising a polyester or copolyester of poly (ethylene terephthalate), wherein the first barrier layer is disposed intermediate to the first polyester or copolyester layer and the second polyester or copolyester layer, and the The second barrier layer is disposed intermediate to the second layer of polyester or copolyester and the third layer of polyester or copolyester. Further advantages of the invention will be set forth in part in the description that follows, and in part will be obvious from the description or may be learned by practice of the invention. The advantages of the invention will be understood and obtained by means of the elements and combinations particularly indicated in the appended claims. It is understood that both the general description mentioned above and the following detailed description are examples only and are not restrictive of the invention as claimed. The present invention can be more easily understood by reference to the following detailed description of the preferred embodiments of the invention and IDS examples therein. It should be noted that, as used in the specification and appended claims, the singular forms "a," "an," and "the," include plural references unless the context clearly expresses otherwise. . The intervals are often expressed in the present as "about" a particular value, and / or at "about" another particular value. When such an interval is expressed, another modality includes from a particular value and / or to another particular value. Similarly, when the values are expressed as approximations, by use of the "approximately" antecedent, it will be understood that the particular value forms another modality. A weight percent of a component, unless otherwise specifically stated, is based on the total weight of the formulation or composition in which the component is included. With respect to polyester,% mol is based on 103% mol of diacid and 100% mol of diol, for a total of 200 mol%. "Optional" or "optionally" means that the event or circumstance subsequently described may or may not occur, and that the description includes cases where the event or circumstance occurs and cases where it does not. For example, the phrase "optionally substituted lower alkyl" means that the alkyl group may or may not be substituted and that the description includes both unsubstituted lower alkyl and lower alkyl where there is substitution. The term "adjacent" means that the layers in the multi-layered structure are in close proximity to each other, and may or may not imply that the layers are in direct contact with each other. The term "contact" means that the layers in the multi-layered structure touch each other, and are not separated by an intermediate layer. The multi-layered structures in this invention contain a first layer which is a polyester or copolyester of poly (ethylene terephthalate) ("PET"), preferably a copolyester of poly (ethylene terephthalate) comprising residues of ethylene glycol and terephthalic acid and further comprise residues of cyclohexanedimethanol and / or isophthalic acid. The first polyester or copolyester layer is typically in direct contact with the contents of the other container and may also be referred to as the inner layer or the innermost layer. The multi-layered structures in this invention also contain a barrier layer, which comprises a residue of a phenylendi (oxyacetic acid), preferably a polyester or copolyester containing a residue of phenylendi (oxyacetic acid), or a mixture comprising a polyester or copolyester of phenylendi (oxyacetic acid). The barrier layer is adjacent to, preferably in contact with, the first layer and may also be referred to as the inner or intermediate layer. The multi-layered structures in this invention may also contain additional layers of a polyester or a copolyester of poly (ethylene terephthalate). The additional layer of poly (ethylene terephthalate) can be referred to as the second, third, fourth, etc., layers. The multi-layered structures of this invention may also contain additional barrier layers containing a residue of a phenylendi (oxyacetic acid). The additional barrier layer can be referred to as the second, third, fourth, etc., barrier layers. In a multi-layered structure having at least three layers, the first barrier layer is disposed intermediate to the first polyester or copolyester layer and the second polyester or copolyester layer. Preferably, the first barrier layer is in contact with both the first polyester or copolyester layer and the second polyester or copolyester layer. In a multi-layered structure having at least five layers, an additional barrier layer having the same composition as the first barrier layer, and a third layer comprising a polyester or copolyester (polyethylene terephthalate) is added to the structure (ie three layers, wherein the second barrier layer is: disposed intermediate to the second layer of polyester or copolyester and the third layer of polyester or copolyester.Preferably, the first barrier layer is in contact with the first layer of polyester or copolyester and the second layer of polyester or copolyester, and the second barrier layer is in contact with both the second layer of polyester or copolyester and the third layer of polyester or copolyester.A layer of polyesters or copolyesters of PET in the Multilayered structure may be the farthest layer of the inner layer, which is also referred to as the outer or outermost layer, which is formed by a polyester (ethylene terephthalate) polyester or copolyester, or a mixture comprising a polyester or copolyester of phenylendi (oxyacetic acid), preferably a poly (ethylene terephthalate) polyester. When the outermost layer is a polyester or copolyester of poly (ethylene terephthalate), either a virgin poly (ethylene terephthalate) or recirculated poly (ethylene terephthalate) can be used, preferably recirculated poly (ethylene terephthalate) can be used. used, preferably virgin poly (ethylene terephthalate). When the outermost layer is formed of a mixture comprising a polyester or copolyester of phenylendi (oxyacetic acid), a protective layer may be provided on the outside of the outermost layer for the purpose of protecting the surface. The protective layer is adjacent to and in contact with the outermost layer of the multi-layered structure. Typical phenylenyl (oxyacetic) compositions are described in U.S. Patents 4,440,922 and 4,552,948, the description of which are incorporated by this reference in their entirety. Mixtures comprising a polyester or copolyester of phenylendi (oxyacetic acid) are also useful as a barrier layer and are described in U.S. Application 09 / 332,629 entitled "high barrier polyester phenylendi (oxyacetic acid) blends", filed on June 14, 1999 and the United States' application NO. 09 / 332,829, entitled "Phenylendi (oxyacetic acid) polyether copolyester mixtures having improved gas barrier properties", filed June 14, 1999, the descriptions of which are also incorporated by reference. U.S. Patent Application No. 09/332, 629 discloses polyester blending compositions comprising: 1. from about 5 to about 85% by weight of a polyester which is the reaction product of: (A) a repeating unit of phenylendi (oxyacetic acid) represented by the formula (I);
(I) wherein R1, R2, R3 and R4 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a group phenyl, a chlorine atom, a bromine atom, or a fluorine atom or an ester derivative of phenylendi (oxyacetic acid) of the formula I: (B) a repeating unit of a diol containing up to 24 carbon atoms; and II. from about 95 to about 15% by weight of a poly (ethylene terephthalate) thermoplastic polyester, a copolyether of poly (ethylene terephthalate) modified with more than 0 to about 70% mol of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol or 1,4-cyclohexanedimethanol, and / or a dicarboxylic acid comprising isophthalic acid or naphthalenedicarboxylic acid, or a mixture of a copolyester of polyethylene terephthalate with polyethylene terephthalate; from about 95 to about 15% of a poly (ethylene naphthalate) polyester, a copolyester (ie, poly (ethylene naphthalate) modified from greater than 0 to 30% by mol of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol or 1,4-cyclohexanedimethanol, and / or a dicarboxylic acid comprising isophthalic acid or terephthalic acid, or a mixture of the copolyester of poly (ethylene naphthalate) with poly (ethylene naphthalate), from about 95 to about 15% poly (butylene terephthalate), from about 95 to about 15% poly (trimethylene terephthalate), or from about 95 to about 15% poly (butylene naphthalate), U.S. Application No. 09 / 332,829 describes compositions of polyester blend comprising: I. from about 5 to about 85% by weight of a copolyester which is the reaction product of components comprising: (A) a repeating unit of a dicarboxylic acid component comprising: (i) from about 5 to 99 mol% of a phenylendi (oxyacetic acid) represented by the formula (I):
wherein R1, R2, R3 and R4 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a phenyl group, an atom of chlorine, a bromine atom, or a fluorine atom, or an ester derivative of phenylendi (oxyacetic acid) of the formula I: (ii) 95 mol% of a repeating unit of a second diacid selected from the group comprising terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or cyclohexanedicarboxylic acid, or ester thereof, or mixtures thereof; (B) a repeating unit of a diol containing up to 24 carbon atoms; and II. from about 95 to about 95% by weight of a poly (ethylene terephthalate) thermoplastic polyester, a poly (ethylene terephthalate) copolyester having more than 0 to about 70% mol of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol, or 1,4-cyclohexanedimethanol, and / or a dicarboxylic acid comprising isophthalic acid, or naphthalenedicarboxylic acid, or a mixture of the poly (ethylene terephthalate) copolyester with poly (ethylene terephthalate); from about 95 to about 15% of a polyester poly (ethylene naphthalate), a copolyester of poly (ethylene naphthalate) modified with more than 0 to 30% by mol of a glycol comprising diethylene glycol, propanediol, butanediol, hexanediol, or 1,4-cyclohexanedimethanol and / or a dicarboxylic acid comprising isophthalic acid or terephthalic acid, or a mixture of copolyester poly (ethylene naphthalate) with poly (ethylene naphthalate); from about 95 to about 15% poly (butylene terephthalate); from about 95 to about 15% polytrimethylene terephthalate; or about 95 to 15% poly (butylene naphthalate). Preferred phenylene di (oxyacetic acids) of the formula (I) include 1, 2-phenylenedia (oxyacetic acid), 1,3-phenylenedia (oxyacetic acid), 1,4-phenylenedia (oxyacetic acid), 2-methyl-1, 3-phenylenedia (oxyacetic acid), 5-methyl-1,3 -phenilendi (oxyacetic acid), 4-methyl-l, 3-phenylendi (oxyacetic acid), 5-ethyl-l, 3-phenylendi (oxyacetic acid), 4-eti.L-1, 3-phenylendi (oxyacetic acid) , 5-methoxy-l, 3-phenylendi (oxyacetic acid), 4-methoxy-l, 3-phenylendi (oxyacetic acid), 4-chloro-1,2-phenylendi (oxyacetic acid), or 4-chloro-l, 3- phenylendi (oxyacetic acid) or an ester thereof. An even more preferred phenylenylene (oxyacetic acid) of the formula (I) includes derivatives of 1,2-phenylenedia (oxyacetic acid), 1,3-phenylenedia (oxyacetic acid), 1,4-phenylenedia (oxyacetic acid), or a ester of the same. Fenilendi (oxyacetic acids) as the dicarboxylic acid component (IA) in the present invention can be used as a raw material of a polyester of the present invention either in the form of an acid by itself or in the form of a derivative ester forming such as an acid halide and an ester, in particular, an ester forming a derivative such as an alkyl ester of Cl-4. Alternatively, an oligomer obtained by reacting a phenylendi (oxyacetic acid) with a glycol can be used for polymerization. The polyester or copolyester component I is present in the range of from about 5 to about 85% by weight of the blend composition, more preferably from about 5 to about 60% by weight of the blend composition and more preferably about 5% by weight. to about 40% by weight of .. to the mixture composition. As the diol component (IB) for the polyester of the present invention, typical diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1, L-butanediol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, 1, 3-bis (2-hydroxyethoxy) benzene, diethylene glycol and a derivative of an aromatic dihydroxy compound. A preferred diol component is ethylene glycol, and typical aromatic dihydroxy derivatives include resorcinol, hydroquinone, Bisphenol A or Bisphenol S. The polyester component II is present in the range of about 95 to about 15% by weight of the blend composition, more preferably of about 95 to about 40% by weight of the blend composition, and more preferably about 95 to about 60% by weight of the blend composition. The preparation of phenylendi monomers (oxyacetic acid) is described in U.S. Patent 4,935,540, the teachings of which are incorporated herein by reference. The polyesters (I or II) of the present invention can be produced by any polymerization method that is conventionally known for a polymerization method for poly (ethylene terhalate). For example, a method of polycondensation can be adopted, the method comprising the steps of directly esterifying terhalic acid and a phenylendi (oxyacetic acid) represented by formula [I] such as 1,3-phenylenedia (oxyacetic acid) and low ethylene glycol. a pressure and thereafter gradually reduce the pressure while increasing the temperature to polycondensen the reaction product. It is also possible to produce a copolyester of the present invention by subjecting an ester derivative of terhalic acid such as dimethyl terhalate, an ester derivative of a phenylene (oxyacetic acid) represented by the general formula [I] such as 1,3-phenylendi ( oxyacetate) of dimethyl and ethylene glycol to an ester exchange reaction, and further polycondensing the reaction product. In the production of such polymer (I or II), it is preferable to use an esterification catalyst, ester exchange catalyst, polycondensation catalyst, stabilizer, etc. As the ester exchange catalyst, at least one known compound selected from calcium, manganese compounds, zinc, sodium and lithium is usable. From the transparency point of view, a manganese compound is more preferred. As the polycondensation catalyst, at least one known compound selected from antimony, germanium, titanium and cobalt compounds is usable. The antimony, germanium and titanium compounds are preferably used. When a polyester blend composition comprising a phenylendi (oxyacetic acid) of the present invention forms the barrier layer, the mixture may contain a polyfunctional compound such as trimethylolpropane, pentacritritol, glycerin, trimellitic acid, trimesic acid and pyromellitic acid or a monofunctional compound such as o-benzoylbenzoic acid in the range that does not impart the effect of the present invention. The polyfunctional or monofunctional compound may be added to the resulting mixture comprising the polyester or copolyester of phenylendi (oxyacetic acid), or the polyfunctional or monofunctional compound may be employed as an additional monomer component to form the copolyester of phenylendi (oxyacetic acid). Such a polyfunctional or monofunctional compound is preferably used in the range of not more than 20 mol% of the diol component (IB). The polyester or copolyester containing a phenylendi residue (oxyacetic acid), or mixtures comprising a polyester or copolyester of phenylendi (oxyacetic acid) described as the barrier layer in the present invention does not exhibit the disadvantages associated with barrier layer constructions. of EVOH or MXD-6. In addition, the use of catechol as the base diphenol to prepare the oxyacetic acid derivative also leads to higher barrier polymers such as those described in US Patent 4,440,922 and 4,552,948 which can also be used to make polyester and polyester blends. / copolyester, such as those described in the application of the United States No.
(05015.0227) and the request no. (05015.0229). In addition to these copolymers, one can also employ a phenoxy resin such as that described in U.S. Patent 4,267,301 and 4,383,101. These resins are particularly well tolerated in the recirculation stream while giving improved barrier to gas permeation. In addition, the polyglycolic acid or copolymers thereof can function in this multi-layered technology as well. The barrier layer in this invention exhibits very high barrier to gas transmission, in particular to carbon dioxide. This is particularly useful in the case of carbonated beverage bottles, including soft drinks, mineral water, beer and the like, since it allows the product stored in such a bottle to retain carbonation over a longer period of time than that observed with bottles made only of poly (ethylene terephthalate), which are now used. This allows a greater "half-life" for the beverage in such a bottle. The half-life is defined as the time it takes for the bottle to lose 15% of its pressure (ie carbon dioxide) A longer half-life is advantageous for the bottling company For current soft drink bottles made of poly (ethylene terephthalate) , for example, smaller sizes such as 20 and 24 ounces need to be kept cold in order to increase the average life of the container to an acceptable level so that the consumer does not open the bottle only to find that the soft drink contained therein is "flat", that is, it has lost a lot of carbon dioxide, so the bottles of the present invention allow an inherently larger half-life which has a distinct disadvantage since the distribution system does not have They depend on keeping the bottles cold to improve the half-life of the product as it is commonly done.This is an advantage for the bottler and transporter since the storage costs The bottles are greatly reduced without the need for refrigeration. There is also an advantage for the consumer since the costs of this special distribution system (so called cold channel distribution) will not pass in the form of higher prices for the soft drink. The use of resins comprising phenylendi (oxyacetic acid) in a multi-layered structure, such as a bottle opposed to a single layer system has several very great disadvantages. Since obtaining an FDA regulation is a long and arduous process, the most important advantage is that the approval process for multilayered bottles is relatively simple and fast. Poly (ethylene terephthalate) has food contact approval but copolymers containing phenylendi (oxyacetic acid) do not. The use of a multi-layered construction, however, allows immediate use of the phenylenedi resins (oxyacetic acid) while the inner layer of the container is poly (ethylene terephthalate). This is true since poly (ethylene terephthalate) acts as a functional barrier against the migration of any components of the copolyesters object in the contained food. This satisfies the law with respect to products in contact with food. Another advantage of the multilayered structures, and preferably bottles of the present invention, relates to a process of the resin to form the desired structure, such as a container. The usual process for manufacturing involves injection molding a preform followed by reheating the preform and blowing in a suitable mold to obtain the final bottle. In the process, the polymer in the same bottle becomes oriented and crystallized so it imparts much greater strength and rigidity to the bottle. This is a necessary step in the preparation of suitable containers to maintain the carbonation pressure obtained in a soft drink bottle. When using a multi-layered preform of the present invention, one can maintain a current pattern design and have a lower permeation rate for the container and thus a longer half-life. A multi-layered polyester hollow container according to the present invention is produced by forming a preform of a multi-layered hollow container wherein at least one layer comprises a polyester or copolyester containing a phenylenedi residue (oxyacetic acid), or a mixture that it comprises a polyester or copolyester of phenylendi (oxyacetic acid), and reinforcing the preform thus obtained at a temperature above the vitreous transition point (Tg) of the polyester at least in the biaxial direction. The multi-stratification can be composed of either two layers or not less than three layers. A multilayer of three to five layers is preferable. In this case, it is preferable that the inner layer of the hollow container is a layer of a polyester or copolyester of poly (ethylene terephthalate). The outermost layer of the hollow container may be a polyester or copolyester of poly (ethylene terephthalate), or a mixture comprising a polyester or copolyester of phenylene (oxyacetic acid), however, a polyester of poly (ethylene terephthalate) is preferable as the outermost layer in terms of surface resistance. When the outermost layer is composed of copolyester or polyester blends containing a phenylendi (oxyacetic acid), a protective layer may be provided on the outside of the outermost layer for the purpose of protecting the surface. The protective layer may be formed in one step to form the preform of the hollow container. Alternatively, the protective layer may be formed after the preform is stretched to thereby produce the hollow container by labeling or the like. The protective layer may be formed of a polymer, an organic coating, or an inorganic coating, preferably polypropylene, an epoxy coating, or a coating based on silica or aluminum or the like. Generally, the total thickness of a container body is 200 to 700 μ, preferably 250 to 600 μ. The thickness of the phenylenylene (oxyacetic acid) containing the polyester layer varies depending on the desired barrier property, but is generally 5 to 300 μ, preferably 10 to 200 μ. Suitable containers of the present invention can also be produced by extrusion blow molding or blow molding biaxial orientation which is conventionally known. In the case of using blow molding of biaxial orientation, the preform of the hollow container is formed, and after the preform is heated to the stretching temperature, it is drawn into a blow mold. The preforms can be produced by forming a bottom preform by injection molding, or a multi-layered pipe, and forming one end thereof in a bottom. When a multi-layered preform is produced, the layers can be formed sequentially from the inner layer by an ordinary injection mold machine or a molding machine having a plurality of melt injection apparatuses, or the respective layers can be extruded from a plurality of injection devices in a single mold one by one, such that the injected poly (ethylene terephthalate) may first constitute the inner layer and the outermost layer, and the mixture comprising the phenylenedi polyester or copolyester ( oxyacetic acid) injected then constitutes a barrier layer. By selecting the injection timing, it is possible to design the preform in this way to have three layers, five layers or more. Alternatively, the multi-layered structure may be formed by separately forming a preform from the polyester and a sleeve or shim from the barrier material. The sleeve can be inserted on the preform at any time before reheating only the preform. Once the sleeve or shim and the preform are in intimate contact the container is formed via conventional blow molding methods. The preform of the obtained hollow container is generally heated in a heating zone having a heater such as a block heater and an infrared heater for the subsequent drawing process. The heating temperature for the preform for a multi-layered polyester hollow container of the present invention is determined by the vitreous transition temperature (hereinafter referred to as Tg of the polyester layer of polyethylene terephthalate). heating is preferably in the range of Tg + 5 ° C to Tg + 80 ° C. If the heating temperature is very low, micro holes are produced due to cold drawing and the container unfavorably presents the pearly or cloudy appearance. On the other hand, if the heating temperature is very high, the preform becomes very smooth to obtain a container that has a sufficient stretching effect. When the preform of a multi-layered polyester hollow container is stretched to form the hollow container, the preform is preferably stretched 1 to 4 times in the machine direction and 2 to 6 times in the transverse direction (hook direction of the container) ) by moving a rod in the direction of the machine and pressurized air blowing. In order to increase the heat resistance of the container, it is possible to set the heat for the container by further heating the hollow container stretched inside the mold at a temperature similar to or greater than the stretching temperature for a short time. The multi-layered structures of the present invention are useful as packaging materials and can also be widely used as a container, sheet, film, etc. A hollow molded polyester product of the present invention, which has a high mechanical strength as well as excellent transparency and gas barrier property, can be widely used for packaging beverages, flavoring material, oil, alcoholic beverages such as beer, wine and sake, and cosmetics. Particularly, the hollow polyester molded product of the present invention can be used as a small size container for carbonated beverages, beer, wine or the like. The improved barrier of the multi-layered structures of the present invention can ensure that the contents can be conserved for extended periods of time. The multi-layered containers of the present invention have excellent gas barrier properties, a high mechanical strength free of ply separation and excellent transparency in external appearance. The multi-layered hollow containers of the present invention can therefore be widely used for fresh drinks, flavoring material, oil, alcoholic beverage such as beer, wine and sake, and cosmetics. Methods for preparing the multi-layered structure and equipment for making it are well known in the art. In this way, the multi-layered structures of the invention can be prepared according to the methods described in any of the US Pat. 5,688,572, 5,221,507, 5,040,963, 5,523,045, 4,751,035, 4,525,134, 4,710,118, 5,200,207, or 4,863,665. The equipment that forms the multi-stratified container is available from Kortec, which is located in Gloucester, Massachusetts. The present invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications may be made within the spirit and scope of the invention.