MXPA99002204A - Oxygen scavenging condensation copolymers for bottles and packaging articles - Google Patents

Abstract

Compositions for scavenging oxygen are disclosed. These compositions comprise condensation copolymers comprising predominantly polyester segments and an oxygen scavenging amount of polyolefin oligomer segments. The polyester segments comprise segments derived from typical bottling and packaging polyesters such as PET and PEN. The copolymers are preferably formed by transesterification during reactive extrusion and typically comprise about 0.5 to about 12 wt.%of polyolefin oligomer segments. The copolycondensates are capable of absorbing at least 0.4 cc of oxygen per gram of copolymer in the solid state at ambient temperatures and are typically used as layers in films, liners, cups, wraps, bottles, etc. Use of these oxygen scavenging compositions in bottles provides a clear and rigid bottle similar in appearance to unmodified polyester bottles. In a series of preferred embodiments, bottles fabricated with the oxygen scavenging copolycondensates of this invention are over 99.4 wt.%polyester and suitable for recycle with other polyester bottles.

Description

CONDENSATION COPOLYMERS FOR OXYGEN ELIMINATION FOR BOTTLES AND PACKAGING ARTICLES FIELD OF THE INVENTION The invention relates in general to compositions, articles and methods for packaging oxygen sensitive substances, especially food products and beverages. The invention is directed to oxygen barrier materials of the type called active oxygen scavenger. The active oxygen scavengers of this invention are copolymer condensation substances which can be used for bottles and packaging. These compositions have a capacity to consume, deplete or reduce the amount in or from a given environment in the solid state at ambient temperatures. Formulations that can be manufactured in clear plastic bottles suitable for recycling with other polyester bottles are described.

BACKGROUND OF THE INVENTION Plastic materials have continued to make significant advances in the plastics industry.

REF. : 29405 packaging due to the flexibility in the design of its material and its capacity to be manufactured in various sizes and shapes, commonly used in the packaging industry. The detachment of plastic materials in films, trays, bottles, cups, glasses, coatings and linings is already the most common in the packaging industry. Although plastic materials offer many benefits to the packaging industry with an unlimited degree of design flexibility, the utility of plastic materials has remained inhibited in situations where atmospheric gas barrier properties are necessary. (mainly oxygen), to ensure adequate shelf life of the product. Compared to traditional packaging materials such as glass and steel, plastics offer inferior barrier properties that limit their acceptability for use in packaging items that are sensitive to atmospheric gases, particularly when exposed to atmospheric gases it implies prolonged periods of time. The packaging industry continues to look for packaging materials that offer flexibility in the design of plastics with the inherent advantage of recycling plastics that at the same time have the barrier properties of glass and steel. The packaging industry has developed technology to improve the barrier properties of plastic containers by developing multi-layer containers that offer mixed layers of polymers. These laminated packaging containers offer improved barrier properties that are close to, but not comparable to, those of glass and steel while sacrificing many of the recycling benefits associated with single-layer containers such as bottles. polyethylene terephthalate (PET) and polyethylene naphthalate (PEN). Furthermore, depending on the mixtures of polymers, copolymers, mixtures, used in the layers, the clarity of the layer container is often substantially decreased. Maintaining the proper balance of recycling capacity, barrier properties, and clarity is the most critical in bottling applications. However, these are common interests among a wide range of plastic packaging uses.

PET has made significant invasions in bottling and packaging applications at the expense of the use of glass containers, but mainly in applications where the needs of barrier properties are modest. A significant example is the use of PET for soft drink bottles. However, the barrier properties of PET have limited its use in the packaging of oxygen sensitive beverages such as fruit juices and beer. The most common size of PET soft drink bottles is the two liter bottle, but one liter and three liter bottles are also frequently seen. The wall thickness of PET used for these large-sized bottles provides an adequate oxygen barrier for these products. The bottling of fruit juice and other oxygen sensitive products in large bottles with thick PET walls has recently been commercialized. The increased wall thickness is necessary to improve the barrier properties of the container, but it has a negative impact on the economy of the recipient. The relationship of the packaging material to the packaging volume has limited PET bottles to uses in multi-service containers for the packaging of oxygen-sensitive foods and beverages. As the oxygen sensitivity of the packaged product increases or as the package size decreases, at some point the ratio of the packaging material to the packaging volume becomes prohibitive. When this occurs, the production of the use of thick-walled PET bottles is not feasible since the cost of packaging is disproportionate to the value of the packaged product. The availability of beverages and food in individual service plastic bottles and containers is an important economic consideration, particularly for use in unusual sales locations such as special events, in stadiums or arenas., And in similar situations where the amount of the product sold is often determined by how quickly the product can be transferred from either a multi-service container to an individual / consumer service. Frequently, the sale of drinks in metal or glass containers, of individual service is productive in these locations due to the possibility that the empty containers can be launched as missiles by rioters attending these events. The sale of drinks in plastic bottles, individual service, however, are normally allowed in all situations. One possibility to extend the economic viability of packaging oxygen-sensitive materials into smaller or individual service containers is to decrease the thickness of the bottle wall to maintain the same proportion of the packaging material to the packaging volume as will be found. for large bottles. However, containers with longer walls made of bottled commercial polyester allow the passage of more oxygen to the packaged product than in the thick walls of the bottle. As such, life on shelf and other required bottle features will not be satisfactory. However, the thin, modified walls of the bottle that maintain or improve the oxygen value characteristics of conventional bottling polyester will provide a response. The use of multilayer bottles containing an inner layer, sometimes interleaved, of a second polymer material, of superior barrier, compared to the outer polymer layers, is already a common thing. Typically, the center layer is a high barrier polymer that exhibits barrier properties by decreasing the oxygen permeability through the wall of the container. This system will be classified as a passive barrier. A common construction for these passive barriers will comprise PET inner and outer layers with a core layer of ethylene-vinyl alcohol polymer (EOVH). Another method to provide increased oxygen barrier properties is the incorporation of the bottle walls of substances capable of intercepting and eliminating oxygen as it attempts to pass through the walls of the container. This method also offers the opportunity to remove unwanted oxygen from the package cavity where oxygen may have been inappropriately introduced during packaging or filling. This method of providing oxygen barrier properties where a substance consumes or reacts with oxygen is known as an "active oxygen barrier" and is a different concept of passive oxygen barriers that try to seal a product of oxygen via the approach passive. One method for the use of active barriers would be to make a three-layer bottle that looks like a bottle of a layer. In the three-layer bottle, the inner and outer layer are made from the same generic family of polymeric materials. The method applies to many packaging items, but in the case of a bottle, the construction will comprise two layers of polyester interspersing an intermediate layer having the outstanding, unusual, oxygen removal characteristics of the outer layers of polyester. When the intermediate layer is very similar to the outer layers of polyester, the article seems to be only an individual layer. Of course, many options exist including the use of a relatively homogeneous monolayer comprising the copolymers of oxygen scavenging. The incorporation of an active oxygen scavenger in the walls of the bottle provides a very effective means for eliminating or at least controlling the amount of oxygen reaching the cavity of the container. However, there are some severe demands that are placed on the walls of active oxygen removal of the bottle. One consideration is that the relatively small walls of the bottle must be of sufficient strength and rigidity to withstand the rigors of filling, packaging and consumer use. The oxygen removal capacity of the walls of the bottle must be of sufficient capacity to allow adequate shelf life and normal product production intervals. Shelf life and production intervals require that oxygen removal must occur for extended periods of time. Most packaged products are stored and transported at room temperature or under refrigeration or that demand the need for oxygen removal activity at these temperatures. Of course, the oxygen scavenger must exist as a solid at these temperatures to be formed and molded into packaging articles, ie, these storage and transport temperatures must be below the vitreous transition temperature (Tg) of the compositions of oxygen removal. The preferred compositions will absorb oxygen at a faster rate than the oxygen permeability through the packaging wall for the planned shelf life of the packaged product as long as it has sufficient capacity to remove oxygen from within the package cavity, if necessary. In these applications, which require clarity, the packaging article must have optical properties that approximate those of the PET. Finally, preferred thin-walled bottles should be suitable for recycling with other polyester bottles. In order to be meaningful, recycling must be carried out without the need for any special physical processing such as delamination or the need for any special chemical that processes this depolymerization. What is needed are oxygen scavenging compositions, methods for the production of these compositions and methods for using the compositions in packaging articles to meet all the demands as cited above.

BRIEF DESCRIPTION OF THE INVENTION AND REVIEW OF THE PREVIOUS TECHNIQUE A number of attempts have been made to prepare removal and / or oxygen barrier bottle walls. Some approaches have included the incorporation of inorganic powders and / or salts in the walls of the bottle. Most of these systems contain numerous drawbacks including poor clarity, poor process properties, insufficient oxygen intake, and non-recyclability. There are numerous approaches that include the use of laminated structures. Most of these have at least one or several disadvantages and most also suffer from the lack of recyclability. The satisfaction of the need for a polyester bottle, thin-walled, recyclable, strong, with a capacity of elimination of oxygen to continue to be the subject of substantial technical and commercial interest. A proposed method to extend the useful range of PET bottles is the incorporation of oxygen scavenging substances in PET. This incorporation will increase the oxygen barrier properties of modified PET by allowing thinner bottle walls that would be ideal for smaller containers, especially for the bottling of oxygen sensitive substances. Naturally, the increase in oxygen barrier properties of PET should be made without sacrificing the outstanding characteristics and properties of PET. For purposes of this invention, the outstanding characteristics and properties of PET include (1) transparency, (2) stiffness, (3) good passive oxygen barrier properties, (4) recyclability, (5) reasonable cost, and (6) A long history of experience and use in the packaging industry. Thus, there are at least two separate considerations comprised in the development of materials and methods that could be used to improve the oxygen scavenging properties of PET. First, it is necessary to identify a list of materials that may possess high oxygen removal capacity, so that only small amounts of these materials are required, for use in the manufactured form. The logic dictates that the use of the smallest amount of material will have the least impact on the outstanding, existing characteristics of the packaging polyesters. However, other considerations have added to the oxygen scavenging capacity which include factors such as cost, clarity, processability, recycling. Second, it is necessary to devise a means to innocuously incorporate the promising, eliminating substances in the packaging and bottling polyesters to form desirable oxygen scavengers.

The present invention is capable of satisfying both of these considerations by developing new condensation copolymer compositions, which predominantly comprise polyester segments and a lower percentage by weight of hydrocarbon segments for oxygen removal. The oxygen removal hydrocarbon segments need to be present only in an amount necessary to provide the degree of oxygen scavenging capacity necessary for the particular application and are comprised of polyolefin oligomer segments that have been incorporated into the copolymer. For this invention, predominantly polyester segments are defined as at least 50% polyester segments based on the weight of the copolymer. Since the copolymers comprise primarily polyester segments, such as PET segments, the properties of the copolymers formed remain very similar to those of the precursor polyester, ie, the unmodified polyester or homopolymer lacking the hydrocarbon removal segments. of oxygen. The oxygen scavenging capacity of these novel copolymers is present at temperatures both above and below their glass transition temperatures (Tg). Nevertheless, a significant advance in the state of the art of oxygen scavenging arising from this invention is the ability of these compositions to remove oxygen at temperatures below the Tg, (ie, in the solid state). The Tg's of the new compositions of this invention are typically above 62 ° C which means that the copolymers can be made or incorporated into packaging articles having a commercial oxygen scavenging capacity at ambient temperatures in the range of 0. ° C to 60 ° C. Also, since the novel copolymers are largely comprised of polyester segments, the constructed bottles comprising the new copolymers are largely comprised of polyester segments, the constructed bottles comprising the new copolymers are suitable for recycling with conventional polyester bottles of other sources and without the necessity of special procedure, methods have also been devised to elaborate the new copolymers and methods for their use in the manufacture of bottles and other packaging articles.

A search of the prior art has appeared some background references. Among those references are U.S. Patents Nos. 5,310,497, 5,211,875; 5,346,644 and 5,350,622 (Speer et al.), Which describe the use of poly (1,2-butadiene) as an oxygen scavenger. But there is no description of the compositions of this invention nor any recognition of the desirability of dispersing this oxygen scavenging capability in a polyester in any way, and its use as segments in a condensation copolymer system is certainly not suggested. Furthermore, these adhesion-type polymers of Speer et al. Describe the function of oxygen only above the vitreous transition temperature of the polymer system. The Tg of the materials by Speer and collaborators is well below the temperatures commonly used for packaging. This is a severe limitation to the polymers of Speer et al. Since it excludes the possibility of manufacturing polymers in rigid packaging articles that have oxygen scavenging capacity. It is well understood by those skilled in the art that below the glass transition temperature the polymer is in a glassy or solid state, which gives the rigidity of the container. In addition, it is also understood by those skilled in the art that oxygen permeability increases significantly above the vitreous transition temperature of the polymeric material. Thus, in these systems where the absorption of oxygen occurs above the vitreous transition temperature, the usefulness of the material is often partly or totally due to the increase in oxygen permeability through the polymer system or in the loss of oxygen. rigidity (form). Simple polybutadienes as high molecular weight addition polymers are, in general, non-rigid and unsuitable on their own to be used as a packaging resin or incorporated as a component of a rigid PET bottle construction. As an example of the prior art directed to the use of butadiene-based copolymers with PET, in general, Japanese Patent Document No. 59196323 (November 7, 1987) improved mechanical properties or impact strengths have been described. for copolymers of hydrogenated hydroxy-teated polybutadiene with oligomers of PET, phenol and terephthalic acid dichloride. It is known that hydrogenation serves to eliminate, or at least severely decrease, the number of tertiary and secondary hydrogens present in butadiene. As will be discussed later in this application, the oxygen scavenging capacity is related to the presence and availability of secondary and tertiary hydrogen atoms in a hydrocarbon substance. The hydrogenation of the butadiene polyolefin unsaturation will serve to remove most of the sites of the secondary and tertiary hydrogen atoms and render this composition impotent in terms of the oxygen scavenging potential. Since the absence of hydrogenating butadiene oligomers in the copolymers of this invention is an important distinction over the prior art. Also, Japanese Patent Document No. 59193927 (November 2, 1984) has described the relative description for the preparation of hydrogenated polybutadiene, amidated, with polyester under catalytic action. U.S. Patent No. 5,244,729 describes the use of polybutadiene maleate with PET as an adhesive (one of many examples) for veulite platelets dispersed in oriented PET or polypropylene to create passive barriers comprising veulite platelets. This dispersion will necessarily be opaque as a result of the specified particle sizes varying from 0.1-5.0 μm, which will interfere with the transmission of visible light. The present invention describes copolymers with very small polyolefin oligomer segments that maintain transparency. Additionally, there is no apparent recognition of the active oxygen removal capacity of the polybutadiene alone functionality or its use without the vermiculite. Japanese Patent Document No. 56129247 (October 9, 1981) discloses a hydrogenated diene copolymer with PET as a nucleating agent for the crystallization of PET. Japanese Patent Document No. 7308358 (March 13, 1983) discloses PET-polybutadiene together with triisocyanates as an adhesive for natural rubber polyester fiber tire yarns. None of these references of the prior art has described or made obvious the copolycondensates of this invention nor their effectiveness for the removal of oxygen, in the solid state.

This invention provides novel compositions in the form of copolycondensates that are effective oxygen scavengers that can absorb oxygen at packaging temperatures that are below the vitreous transition temperature of the polymer compositions when deployed on the walls of plastic bottles or bottles. when incorporated into other packaging materials such as films, cups, cartridges, bottle liner covers, boat linings, food bags, trays. In a series of embodiments of this invention this has been achieved by the preparation of copolymers capable of absorbing oxygen in the solid state below their vitreous transition temperatures, comprising predominantly polyester segments with a sufficient amount of polyolefin oligomer segments. to achieve the required oxygen removal capacity. Methods for the preparation of the copolycondensates of this invention are also described. In a preferred embodiment, the copolycondensates are prepared by transesterification by extrusion with reaction of the polyester with polyolefin oligomers which have been functionally terminated with terminal groups capable of being introduced into the polycondensations. Methods for protecting the oxygen sensitive substance by proper packaging are also described in a series of embodiments wherein the oxygen sensitive substances are packaged in a suitable article of manufacture comprising the copolymers described above in an amount sufficient to serve as a barrier to oxygen. In various embodiments of this invention, plastic bottles of sufficient oxygen removal capacity are described to allow the bottling, transportation, storage and sale of oxygen sensitive substances such as fruit juice without the need for refrigeration or cooling. . Finally, various bottling modalities of this invention describe polyester bottles having a commercial oxygen scavenging capacity which are suitable for recycling with other polyester bottles without the need for any special processing.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of the preferred wall and film construction of the oxygen scavenging bottle.

Figure 2 is a copy of a microphotograph at 60,000 increase in cross section cut from a copolymer film of this invention showing the polyolefin oligomer segment of the copolymer that has been stained with Os04.

Figures 3-5 are graphs showing the size distribution of the diameters of the polyolefin oligomer segments of the copolymers as determined by transmission electron microscopy.

Figure 6 is a graph demonstrating the oxygen scavenging capacity of the copolycondensates of this invention at two molecular weights of polyolefin oligomer versus unmodified polyester.

Figure 1 is a graph showing the effect of the molecular weight of the polyolefin oligomer on the clarity of the copolymer.

Figure 8 is a graph comparing the clarity of the films of the PET copolymers of this invention in a non-oriented vs. biaxially oriented fashion.

Figure 9 is a graph comparing the clarity of the films of the PET copolymers of this invention to that of PET without modification.

Figure 10 is a graph showing the effect on oxygen removal rates and the ability to add cobalt to the copolymers of this invention.

Figure 11 is a graph comparing the oxygen scavenging capacity of the copolymers of this invention to that of the commercially available oxygen scavenging system.

Figure 12 is a graph comparing the oxygen scavenging capacity of the copolymers of this invention to that of unreacted starting materials.

DESCRIPTION OF THE PREFERRED MODALITIES The polyesters, including PET, used for the manufacture of plastic bottles and other packaging items may be the same polyesters from which the polyester segments are derived in the same oxygen scavenging condensation copolymers described herein. Frequently, these polyesters are prepared by polymerizing together (typically on an equimolar base and in the appropriate catalyst source) two separate chemical monomers as shown in Formula I and Formula II to form the repeating polyester units depicted in Formula III.

Or o ?? n I. H-O-C-RI-C-O-H II. H-0-R2-0-H O or II 11 III. (-O-C-R1-C-0-R2) R1 in the dicarboxylic acid monomer of Formula I is frequently, but not necessarily, a divalent aromatic radical that usually has one, two or three aromatic rings, which in turn can be fused or separated when R1 represents multiple rings. R1 may also be aliphatic, and alicyclic, or mixtures of aromatic, aliphatic or mixtures of aromatic, aliphatic, and alicyclic in any possible combination in the case of polyester copolymers. For PET, R1 is the divalent 1,4-phenyl radical and Formula I will represent terephthalic acid. The conferred species of Formula I are terephthalic acid, isophalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, other isomers of naphthalenedicarboxylic acid, and mixtures thereof, and mixtures of at least one of the preferred species with other species encompassed by Formula I. Especially preferred are terephthalic acid, 2,6-naphthalene dicarboxylic acid, mixtures thereof and mixtures of at least one of the especially preferred species with other species encompassed by Formula I. R 2 in the diglycol monomer of Formula II can be any divalent alkylene or substituted alkylene radical, or mixtures thereof. For bottling and packaging polyesters, R 2 is frequently, but not necessarily, a divalent alkylene racial of 2 to 4 carbon atoms. For PET, R 2 is divalent 1,2-ethylene and Formula II will represent 1,2-dihydroxy-e. Preferred species of Formula II are 1,2-dihydroxy-anus, 1,3-dihydrixi-propane, 1,4-dihydrix-butane, cyclohexanedimethanol and mixtures comprising at least one of the four preferred combinations as far as possible , among themselves or other species covered by Formula II. Especially preferred is 1,2-dihydroxy-ethane alone or mixed with other species of Formula II. In some greater detail, the preferred polyester resins grouped for use in the present invention include linear polymers of an aromatic dicarboxylic acid component and a diol component. Examples of the dicarboxylic acid components include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyl ether carboxylic acid, diphenyldicarboxylic acid, dicarboxylic acid-di phenylsulfone and fifenoxietanedicarboxylic acid. Examples of the diol components include ethylene glycol, tetramethylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene glycol, cyclohexanedimethanol, tricyclodecanmethanol, 2,3-bis (4-p-hydroxy-ethoxy-phenyl) propane, 4, 4, -bis- ( p-hydroxy-ethoxy) diphenylsulphone, diethylene glycol and 1,4-butanediol Polyesters prepared from the above components are well known in the art, and can be prepared via the dicarboxylic acid, or suitable derivatives such as dimethyl esters of the above acids. In many cases, polyesters suitable for use in this: invention are available for purchase from a variety of suppliers. Examples of polyesters that can be employed in the present invention include polyethylene terephthalate, polybutylene terephthalate, polybutylene terephthalate elastomer, amorphous polyesters, polycyclohexane terephthalate, polyethylene naphthalate, polybutylene naphthalate and mixtures thereof. Specific examples of commercially available polyester resins useful in the present invention are Goodyear PET resins 7207 and 9506 ("C-PET"), PET TR8580 resins, from Tejin 'Limited and Eastman PET resin 9902. Kodak. In selected embodiments, the present invention also contemplates the use of recycled PET as part of the feed wherein the recycled PET may already contain low levels of branching agents or other actives originally formulated therein. Other polyester resins suitable for use in the present invention include branched polyesters. These branched species could be prepared using mainly carboxylic acid type, difunctional monomers together with some carboxylic acid monomers having a functionality greater than two and then polymerizing these acids with polyols. Alternatively, the branched species can be prepared using mainly diol monomers together with some polyols having more than two hydroxy groups and then polymerizing these polyols with acid monomers with a multifunctionality. Examples of acids having functionality greater than two include trimellitic acid and pyromeryl acid (or their anhydrides). Polyols that have greater functionality than two include glycerol, pentaerythritol. Especially preferred for this invention are polyesters comprising repeat units selected from the group consisting of those encompassed by Formula IV and Formula V, and wherein n in each of Formulas IV and V has a value in the 2-4 interval.

Formuls When the monomers of Formula I and the monomers of Formula II react to give the repeating structure of Formula III, water vapor is formed during the reaction. This type of polymerization is known as polycondensation or condensation polymerization. While the reason for this nomenclature is not important, it seems likely that water vapor formation during the reaction will contribute to the use of terminology such as condensation polymerization. In the book "GLOSSARY OF CHEMICAL TERMS" by C.A. Hampel and GG Hawley, von Nostrand, 1976, provides a definition for condensation polymerization on page 67. According to this reference, a condensation polymer is a linear or three-dimensional macromolecule made by the reaction of two organic molecules usually with the formation of water or alcohol as a by-product. The reaction is repetitive or of several steps as the macromolecule is formed. These repetitive steps are known by polycondensation. Among the examples data as condensation polymers are polyesters and polyamides. In 1929, Carothers (W. H. Carothers, J. Am. Chem. Soc. 51, 2548 (1929)) proposed a generally useful differentiation between two branched classes of polymers. One of the Carothers classes was the condensation polymers in which the molecular formula of the structural unit (repeating) or units in the polymer lacks certain atoms present in the monomer or monomers from which it was formed, or the which can be degraded by a chemical medium. The other class of Carothers was the addition polymers in which the molecular formula of the structural unit (repeating) or units in the former is identical with that of the monomer from which the polymer is derived. The polymers and copolymers of importance in this invention are those which Carothers would have considered to be condensation polymers in view of their polymerization characteristics and the formulas of the repeating units in the polymers against those of the forming monomers. In one aspect of this invention, new condensation copolymers are described which predominantly comprise polyester segments of the types encompassed by Formulas IV and V, and oxygen alignment hydrocarbon segments in an amount effective to provide the required capacity for elimination of oxygen. As will be explained in detail below, these hydrocarbon segments of the condensation copolymer are actually oligomers of an addition polymer.

While Formula I represents a species of dicarboxylic acid and Formula II represents a species of dihydroxy, it will be recognized by those skilled in the art that there are numerous different possibilities which, when reacted together, will lead to the polyester structure of repetition shown by Formula III, as examples, Formula I could be a diacid halide or a diester of a dicarboxylic acid and still lead to the structure shown in Formula III when reacted with a species of Formula II. Of course, the byproduct will be something different from water in these cases. In a similar manner, the replacement of one or both hydrogen atoms by an organic group in the dihydroxy species of Formula I will still yield a repeating polyester structure of Formula III when reacted with a species of Formula I . The byproduct will probably be an alcohol instead of water in these cases. In general, the end groups in the monomers used in the formation of the bottling and packaging polyesters (which will eventually become the majority of the segments in the oxygen scavenging copolymers of this disclosure), are relatively unimportant to this. invention. It will be understood by those skilled in the art that the polyester segments once formed (and in spite of the monomers from which they were formed) will still function in the manner as prescribed by this invention. In a related way, it will be appreciated by those skilled in the art that the preferred species of Formula I and Formula II cited above will also encompass these terminal, alternative functional groups that essentially lead to the formation of the same polyesters and polyester segments. An important concept in this invention is the formation of copolymers comprising predominantly polyester segments derived from the bottling and packaging polyesters described above as one of the components of the copolymer. The oxygen scavenging copolymers of this invention are copolycondensed comprising predominantly polyester segments and hydrocarbon segments wherein the hydrocarbon segments need only be present in sufficient quantity to provide the necessary oxygen scavenging capacity. As will be shown in the following examples, the oxygen scavenging compositions of this invention are, in fact, 100% copolymers. However, due to the low percentage by weight of the hydrocarbon employed, the hydrocarbon segments appear to exist as areas of hydrocarbon segments of oxygen scavenging capacity dispersed throughout the predominantly present polyester segments of the copolymer. These are the areas of hydrocarbon segments, of course, that really account for the oxygen removal capacity of the copolycondensates since the hydrocarbon segments are the only portions present that have predisposition and oxygen scavenging capacity. Of course, it was necessary for the applicants to focus on the evaluation and selection of the appropriate hydrocarbon segments that could be incorporated into a condensation copolymer and on the • necessary oxygen removal capacity as long as they do not disrupt the outstanding characteristics and properties. of the packaging polymers and segments derived therefrom for the copolymer. The applicants are in favor of the theory that the mechanism of oxygen admission in hydrocarbon materials is by fixation of oxygen on the hydrocarbon material via the formation of hydroxy groups. In addition, this same theory proposes that hydroxy groups that consume oxygen are formed via a free radical process that comprises a portion of intermediate peroxy and that carbon atoms that have only one bound hydrogen (a hydrogen called tertiary) are more susceptible to the formation of free radicals that the carbon atoms with two hydrogens attached) the so-called secondary hydrogens, which in turn are more susceptible to the formation of free radicals of the carbon atoms with three hydrogen attached. Applicants recognize that hydrocarbons such as polyolefins, especially polydienes, provided a potentially good source of secondary and tertiary hydrogens. Further analysis confirmed that polyolefins in general are good candidates for oxygen removal segments, particularly when used as low molecular weight polyolefin oligomers. Preferred polyolefin oligomers for use as. Hydrocarbon segments in the copolycondensates of oxygen removal are polypropylene, poly (methyl) 1-pentene and polybutadiene. Insofar as it is not a hydrocarbon material as such, the glycol oligomer of propylene oxide was also identified as a potentially useful oxygen scavenging substance. Of these, the polybutadiene oligomer is especially preferred since it has a high predisposition for oxygen removal and also because it is commercially available in the form necessary to make the oxygen scavenging copolycondensates of this invention by the preferred method of this invention. . As noted previously, the polyolefin oligomer segments need to be present in the copolycondensates of this invention only to the extent necessary to give the desired oxygen scavenging capacity. One reason for maintaining the polyolefin oligomer segments at only the required level is to satisfy the goal of keeping the as-built copol as similar as possible to the polyester homopolymer. In practice, it has been found that the sequence of the polyolefin oligomer segments in the range of 0.5% by weight to 12% by weight based on the weight of the polycondensate is a typical range of use in percent by weight. Preferred is the presence of polyolefin oligomer segments in the range of 2% by weight to 8% by weight plus the weight of copolycondensate. Especially preferred is the presence of polyolefin oligomer segments in the range of 2 wt% to 6 wt% based on the weight of the copolycondensate. The selection and use of an appropriate molecular weight for the polyol'efine oligomer segments can be an important consideration depending on the end use since it can affect the properties of the oxygen elimination copolycondensates. For a given loading level of copolycondensates in terms of the weight percent of polyolefin oligomer segments, it is possible to use low molecular weight oligomer and finish with a higher mole percent of polyolefin oligomer segments to be made when using a high molecular weight polyolefin oligomer at the same weight percent load level. Intuitively, it would appear that (in the absence of data to the contrary) the use of low molecular weight polyolefin oligomer segments results in a more uniform dispersion of the oligomer segments throughout the copolymer. Also, it will appear that the use of lower molecular weight oligomer segments will cause the segments to be physically smaller than the segments obtained at the same loading level with the higher molecular weight oligomer segments. The size in the cross section (diameter) of the polyolefin oligomer segments is important in applications where the clarity of the copolycondensates is a requirement. The polyolefin segments appear to inhibit (scatter) the transmission of light when there are too many segments around the size of the wavelengths of visible light. In a previous and more extensive discussion of this subject, it will be shown that other factors affect the size of the oligomer segments in addition to the molecular weight of the oligomer. As part of this discussion, detailed conditions will be described to control the size of the oligomer segments to achieve the desired optical, physical and elimination properties for the copolycondensates. However, it should be noted at this point that it has been found experimentally that a preferred molecular weight range for the polyolefin oligomer is in the range of 100 to 10,000. The use of molecular weight is within this preferred range results in copolycondensates having the desired physical and oxygen scavenging properties. The use of the polyolefin oligomer having molecular weights within the especially preferred range of 1,000 to 3,000 results in polycondensates that not only meet the physical and oxygen removal requirements, but also satisfy the clarity requirements in applications where the clarity. A series of discussions is held with representatives of the packaging stry pointing out the establishment of the minimum requirements that will be satisfied by the compositions of active oxygen scavenger. From these encounters came a minimum requirement of transparency for the clarity of the oxygen scavenger copolycondensates of approximately 70% of that of unmodified homopolymer or PET or other polyesters and a minimum oxygen scavenging capacity of approximately 0.4 ce of oxygen per gram. of copolymer at ambient temperatures. An oxygen scavenging capacity of approximately 0.4 ce oxygen per gram is a typical value for other commercially available oxygen scavenging systems. As is the case for the homopolymer polyester, the clarity of the copolycondensates is improved after the biaxial orientation, a procedure that is common to most manufacturing processes contemplated by copolycondensates. The copolycondensates as characterized in the above description will generally have a clarity of at least 70% (at a typical film thickness of 1 to 10 mils. (0.0025 to 0.025 cm), after the biaxial orientation, of the homopolymer or unmodified polyesters tested identically. Also, the copolycondensates will generally have an oxygen absorption capacity of at least 0.4 cc of oxygen per gram of copolycondensate at room temperature defined as being in the range of 0 ° C to 60 ° C. Typically) the copolycondensates will have to give an individual Tg, as measured by differential scanning calorimetry (approximately 65 ° C). The copolymers of this invention have the ability to absorb oxygen in the vitreous solid state at ambient temperatures of 0 ° C to 60 ° C. This functional range for the copolycondensates is below the Tg of these compositions. Their behavior is in marked contrast to prior art oxygen scavengers that absorb oxygen at room temperature (or even colder) but still above the Tg. It is well understood that gas permeability is greatly increased above the Tg when the material is no longer a solid and therefore serves to nullify the elimination utility of these scavengers. Of course, these prior art scavenger compositions are relatively non-rigid at room temperature when they are above their Tg. Another major advantage of the copolymers of this invention, particularly in comparison to the oxidizable metal / electrolyte formulations, is that they will remove oxygen in the absence of water or moisture. The use of oxygen scavenging copolymers of this invention is permitted for the packaging of dry materials such as electronic components, dry foods, medical articles, etc. This ability to remove oxygen in a dry environment further distinguishes the oxygen scavenging copolymers of this invention over many prior art scavengers that require the presence of water or at least one humid environment. In general, the preparation of the oxygen elimination copolycondensates, described above, will comprise a step comprising adding the functionality to at least one or more (preferably more) of the terminal sites available in the eliminating polyolefin oligomer that is going away. to be incorporated as a segment in the copolycondensates. The added terminal functionality must be a portion capable of being introduced into the polycondensation reactions and forming in the polycondensation reactions and forming polycondensation bonds when incorporated into a polymer. It will be understood that there may be more than two terminal sites available for functionalization when there is crosslinking or branching in the polyolefin oligomer. In cases where di or multiple functionality is contemplated, they will generally be multiples of the same functionality, i.e., all hydroxy, all carboxy, or all amino added to plural terminal sites of the polyolefin oligomer molecule. Those skilled in the art will recognize that this invention can still be practiced with different, but chemically compatible, terminal functional groups, which are present at plural terminal sites of the polyolefin oligomer molecules. As previously noted, the only requirement is that functional end groups must be capable of introducing a non-exhaustive list of functional end groups into polycondensation reactions including hydroxy, carboxylic acid, carboxylic acid anhydrides, alcohol, alkoxy, phenoxy , amine and epoxy. Preferred functional, terminal groups are hydroxy, carboxylic acid and amino. It will be obvious that this step in the preparation can be avoided by using polyolefin oligomers which are already appropriately already functionalized at the end and are commercially available as such. In this regard, the terminal, dihydroxy functional groups are especially referred to by applicants since the hydroxy terminated polyolefin oligomers suitable for incorporation into the oxygen scavenging copolycondensates of this invention are commercially available and offer attractive properties. Additional understanding of the processes can be obtained by considering the chemical species represented by Formula VI, VII, and VIII. 0 O H II SAW. H-O-C-PSD-C-O-H VH B-O-PSD-O-H VIII. H2N-PSD.NHj In Formulas VI, VII and VIII, PBD represents a divalent polybutadiene oligomer molecule. Although Formulas VI, VII and VIII show di functionality, it has already been pointed out previously that the PBD can be only slightly functionalized it can be functionalized to a degree greater than two, when the cross-linking and branching of the PBD, offers more than two terminal sites of functionalization In the absence of clarity requirements, the molecular weight of the PBD oligomer molecule is not critical while the functionalized PBD can be further dispersed as hydrocarbon segments throughout the copolycondensates of oxygen scavenging after separation. the same. Finally, in the examples section of this specification, it will be shown that a true copolymer is formed, instead of a mixture or PBD and polyester. The molecular weight of the PBD oligomer can influence the final properties of the copolymers formed in terms of clarity, rapidity and oxygen scavenging capacity. Those skilled in the art will understand the need to balance the properties based on the needs of the end uses and by selecting the molecular weights of PBDs that satisfy the end use. Formula VI, the PBD ends with dicarboxy. In Formula VII, the PBD is terminated with dihydroxy, and in Formula VIII, the PDB is terminated with diamine. While Formulas VI, VII and VIII show the hydrogen forms for these species, it will be understood by those skilled in the art that of all the hydrogens in each of Formulas VI, VII and VIII may be replaced by an organic radical such as alkyl, cycloalkyl, phenyl, and still serve the same purpose in the preparation of the oxygen scavenging copolycondensates of this invention. The use of the substituted forms of the species of Formulas VI, VII and VIII will simply produce by-products in the formation of the copolymers. As noted above, this invention can be practiced with only one functional group per PBD with more than two functional groups per PBD. In Formulas VI, VII and VIII, di functionality is shown but represents one of many levels of possible functionality. The method of forming these functionally-terminated species is not important in the description of this invention. Conventionally available forms of Formula VI, (which is especially preferred), include the R20LM and R45HT products of Elf Attochem, a-ip-polybutanediols. The similarity of the chemical structure of the species represented in Formula I and VI is easily discernible. Since polycondensation occurs by the reaction of the end groups, the copolycondensates can be formed comprising predominantly polyester segments with some polyolefin oligomer segments. For an easier understanding of the composition, it may be useful to think in terms of substituting the desired amount of the species of Formula VI for an equivalent amount (based on moles) of the species of Formula I that produce the copolycondensates. which have segments of both polyester and polyolefin oligomer. As noted previously, the copolymers are truly copolycondensed with the unusual feature that some of the segments consist of the addition polymer (actually oligomer). In the same way, the similarity of the species of Formula II and Formula VII can be easily seen. The copolycondensates can be formed by substitution of the desired amount of the species of Formula VII by an equivalent amount of the species of Formula II. The nature of the polycondensation reaction forming the copolycondensates for these two types of segment substitutions will be similar to that found for the formation of a true or unmodified polyester. It will be expected that the by-products formed are also similar. The species of Formula VIII are finished in diamino. A desired amount of these species can be substituted for an equivalent amount of the species of Formula I to produce a light type of copolymer. When it is prepared in this way, a condensation copolymer is formed where the bonds in the vicinity of the polyolefin oligomer segments are polyamide linkages. As will be shown below, these represent only a smaller percentage, for example, of the non-polyester linkages and the copolycondensates produced having some polyamide bonds are suitable for the purposes of the present as are copolycondensates of this invention prepared with 100% of polyester links between the segments. Significant matter is that the polyolefin oligomer with oxygen scavenging capability has been implanted in the copolycondensate as segments thereby eliminating an oxygen scavenging capability of the formed product while maintaining virtually all of the outstanding characteristics of the original bottling / bottling polyester. These techniques for introducing the desired polyolefin oligomer into the polycondensate when used at low levels described by the applicants, provides a very accurate and effective means for dispersing the oxygen removal portion throughout the copolycondensates. The achievement of uniform dispersion of the oxygen removal portion in the copolycondensate while maintaining the properties of the precursor polyester is a key feature of this invention, which distinguishes the oxygen scavenging copolycondensates of this invention from the prior art. The attempt to produce oxygen scavenging materials by making a physical mixture of the non-functionalized polyolefin oligomer and the polyester generally produces an opaque, non-rigid emulsion which is not useful for packaging. However, when the functionally terminated polyolefin oligomers are mixed or stirred with polyester at temperatures in the range of 200 ° C in order to melt the polyester, the copolycondensates of this invention will be formed, at least to some degree, by transesterification. It should be noted that commercially available PET typically has some cobalt itself, from its separation. Cobalt can act as a transesterification catalyst. Therefore, blends and preparations of polyolefin oligomers functionally terminated with polyester, even if designated as such, may be within the scope of this invention since the processes of mixing and preparation at the melting temperatures of polyester produce the copolycondensate compositions of this invention. The starting material of the preferred polyolefin oligomer is the species of PBD, dihydroxy terminated having a molecular weight in the range of 100-10,000. The starting material of the polyolefin oligomer, especially preferred is a species of PBD terminated in dihydroxy having a molecular weight in the range of 1,000-3,000. The copolymers formed using PBD within the range of the preferred molecular weight will generally have an individual Tg (as measured by differential scanning calorimetry) of about 65 ° C 'and offer the ability to absorb oxygen at temperatures below the Tg. While individual Tg copolymers are preferred, it will be understood by those skilled in the art that multiple Tg copolymers are also applicable, as long as the glass reaction temperature is a temperature above the packaging use temperature. The benefit of having a Tg above the packaging use temperature is to give design flexibility to the container associated with the rigidity of the container. It is well understood that the container stiffness can also be controlled by the wall thickness by allowing flexible films to be produced by a graduation with copolymers. The copolymers of this invention can be produced using any form of polycondensation processes including batch reaction methods and / or continuous, direct, commonly used in the manufacture of PET. The only deviation in the process is that instead of using, for example 50 mol% of a species of Formula I and 50 mol% of a species of Formula II, some of at least one of the species of Formulas VI, VII or VIII, is included and a corresponding molar amount of the species of Formulas I or II, of the polymerization process. Alternatively, the copolycondensates can be prepared by taking a polyester, such as PET, and further polymerizing it with the functionally finished polyolefin oligomer by heating the components to obtain a molten homogenization in an extruder. The heating of the extruder must be achieved under vacuum or non-vacuum conditions. Those skilled in the art will recognize this form of processing as reactive extrusion. In these reactive extrusion processes, the polycondensation occurs and the product is, in whole or in part, a copolymer comprising segments of the starting polyester and polyolefin oligomer segments instead of a melted mixture provided by the individual starting components. Reactive extrusion as described above, is the preferred method for making the copolycondensates of this invention. In direct polycondensation processes, the substitution of the desired amount of the functionally terminated polyolefin oligomer for about an equivalent amount of one of the unmodified condensation polymer monomers results in the high molecular weight copolymer. In this case, the desired amount of the functionally-terminated polyolefin oligomer can replace equivalent molar amounts of one of the polyester monomers. In the case of direct polycondensation, the amount of the functionally terminated oxygen-absorbing polyolefin oligomer can be varied widely while the resulting copolymer exhibits the desired, terminal state properties such as clarity and elimination capacity required for the proposed end use. In general, when packaging incorporation is prepared in advance, it is necessary to keep the copolycondensates in an inert environment during storage. In most cases, the oxygen removal capacity of the copolycondensates is present as soon as they are formed and a period of induction of oxygen exposure has elapsed. The potential to eliminate oxygen must be significantly reduced if left exposed to oxygen (or air) for prolonged periods. Additionally, prolonged exposure to high temperature in the presence of oxygen can further reduce the oxygen absorption capacity of the copolymers, when processed in a packaging article and introduce the possibility of thermal decomposition and degradation. If it extends extensively. The premature loss of oxygen scavenging capacity before the conversion of the copolymers into a packaging article can be controlled by storing in an inert environment or by the addition of suitable stabilizing agents. While the copolycondensates of this invention can be made by any suitable process, including those not yet invented, the preferred method of making the copolycondensates of this invention is by reactive extrusion as described briefly above and in more detail below and again in the examples section of this specification. As part of the extrusion process with reaction, either alone or in combination with the manufacturing step, the starting polyester, such as PET, in the extruder is maintained under an inert atmosphere, preferably provided by a blanket of nitrogen. The functionally terminated polyolefin oligomer is transported separately to the extruder and is introduced into the mixing zone of the extruder. The speed of introduction of the polyester in the extruder is adjusted to allow a sufficient residence time to operate the polyester and make it react with the functionally-terminated polyolefin oligomer to produce the copolymer by transesification. The residence time is from 3 to 5 minutes at the preferred temperature range of 250-280 ° C. The functionally terminated polyolefin oligomer is introduced through an orifice stopped from the extruder and the rate of introduction of the polyolefin oligomer is adjusted to provide the amount of polyolefin oligomer segments necessary to achieve the desired oxygen removal capacity in the copolicondensados. A typical range of polyolefin oligomer segments is from 0.5% by weight to 12% by weight of the total weight of the copolycondensate product. A transesterification catalyst is also used, such as a transition metal carboxylate, in the extruder in a range of 10-300 ppm of the mixture in the extruder. Cobalt carboxylates are the preferred transesterification catalysts and especially preferred is cobalt octoate since it causes the reaction to proceed rapidly and is commercially available at reasonable cost and is ready to be used at concentration levels. As noted above, the transesterification reaction was allowed to proceed in the extruder for 3-5 minutes at a temperature of 250 ° -280 ° C. Under these conditions, the functionally terminated polyolefin oligomer forms a copolymer with the polyester via transesterification. For purposes of understanding, the transesterification can be through a reaction whereby the functionally-terminated polyolefin oligomer species are replaced by some of the previous monomeric polyester species originally present in the starting polyester. In spite of the mechanism, the copolymer is formed for functionally-terminated polyolefin oligomer species, individually and multiplely. When the copolymer is made using the reactive extrusion process, the incorporation of the functionally terminated polyolefin oligomer usually forms a copolymer with a molecular weight less than that of the starting polyester. These can be controlled some degree. by using vacuum to remove any low molecular weight byproduct from the condensation reaction. Again, in spite of the mechanism, some of the species encompassed by the above Formulas VI, VII, and VIII are incorporated as segments in a condensate comprised predominantly of segments of the starting polyester frequently with the appearance that they are substituted by some of the monomeric species specials covered by Formulas I and II above. For a more detailed discussion of the transesterification process, see page 322 in the book "Advanced Organic Chemistry: Reactions, Mechanisms, and Structure" by Jerry March, McGraw-Hill, Inc., 1968. As will be demonstrated by the data in In the example section of this disclosure, a true copolymer is formed under these conditions as opposed to a mixture or preparation of the starting components. Also, these copolycondensates typically exhibit only an individual vitreous transition temperature in the range of about 65 ° C. The copolycondensates formed via the reactive extrusion as described above have only limited amounts of polyolefin oligomer segments that appear to exist as small dispersions throughout the predominantly polyester segments of the copolycondensate. The existence of small polyolefin oligomer segments dispersed throughout the copolycondensate is confirmed by electron microscopy data using 0s04 staining as will be shown in the examples presented later in this description. The size of the control of the polyolefin oligomer segments is important since it is necessary that these polyolefin oligomer segments have cross-section (diameter) measurements predominantly in the range of less than about 3000 units of Angstroms when clarity is required as described previously. The desired size and range of distribution in the sizes of the polyolefin oligomer segments can be achieved by controlling the reagents and the reaction conditions. The examples presented later in this description showed the effect of various reaction parameters and reagents on the size of the oligomer segment and the size distribution of the segment. As noted above, the reaction temperature is maintained in the preferred range of 250-280 ° C, with an especially preferred temperature range of 260-270 ° C. The residence time of the extruder is maintained in the range of 3-5 minutes with an especially preferred time of about 4 minutes. While the amount of the polyolefin oligomer segments in the copolycondensates is determined by the desired capacity of oxygen removal, is typically in the range of 0.05% by weight to 12% by weight. The preferred amount of the polyolefin segments is in the range of 2% by weight to 8% by weight especially preferred is the range of 2% by weight to 6% by weight of polyolefin oligomer segments. The molecular weight of the functionally-terminated polyolefin oligomer employed can vary widely with a preferred range of 100 to 10,000 and a molecular weight range, especially preferably 1,000 to 3,000. A transesterification catalyst of transition metal, such as cobalt carboxylate, is also employed in the extruder in a catalytic amount. The preferred range of the catalyst is from 10 to 300 ppm with an especially preferred range of 50 to 200 ppm. It should be noted that PET, as is commercially available, commonly contains cobalt catalyst from its manufacture. The preferred transesterification catalyst is cobalt octoate. When it is prepared via a reactive extrusion process in which the pellets are formed and then stored, it is more desirable to control the admission of the copolymer in order to minimize the need to dry prior to manufacturing in the packaging article. The moisture admission control can be achieved by a two-step process.

First, the copolymer extrudate can be cooled using a non-aqueous, rapid quench, cooling process prior to pelletizing as described in US Patent No. 5,536,793. This process allows the preparation of pellets with low humidity. The pellets are then sealed directly in moisture proof containers (eg, canister) for storage. "The pellets can be stored directly in the subsequent steps of fusion processing commonly used in the packaging industry, such as extrusion blow molding, film molding, sheet extrusion, injection molding, melt coating. If drying is required, it is desirable to dry the pellets in a vacuum oven or in a drying oven that is covered with a blanket of nitrogen.In order to minimize the loss of utility of the copolymer oxygen scavenger, the The copolymer can be produced during the melt manufacturing step used to make the packaging article This is dependent on the flexibility of the manufacturing process and is typically preferred for extrusion-type processes such as form extrusion or sheeting As will be explained later , the copolymers are relatively safe from obvious oxygen attack once they are incorporated into a bottle or film. In theory, it would be desirable to incorporate the largest possible amounts of functionally terminated polyolefin oligomer into the copolycondensates since this is the oxygen consuming portion and subsequently determines the oxygen scavenging potential. However, there are other considerations that include the desirability of greatly maintaining the outstanding properties of the packaging start polyester. The sizes of the oligomer segments are widely varied and the polycondensates produced usually contain some oligomer segments whose diameters are distributed outside the preferred diameter range below approximately 3,000 Angstroms despite the controls employed. The range below approximately 3,000 Angstroms is preferred because segments with diameters in that range have only a minimal effect on the transmission of visible light.

It has been found by applicants that deployment of the functionally terminated polyolefin oligomer in the range of 0.5 wt% to 12 wt% using molecular weights for the oligomers in the range of 1,000-3,000 will produce copolycondensates having the size distribution of Preferred polyolefin oligomer segment diameter, predominantly below about 3,000 Angstroms units. In addition, these copolycondensates will generally have a clarity of at least 70% (a typical film thickness of 1 to 10 mils (0.0025 to 0.025 cm)) of the precursor polyester. These copolycondensates will also generally have an oxygen absorption capacity of at least 0.4 ce of oxygen per gram of copolycondensate at temperatures in the range from 0 ° C to 60 ° C using the method for determining oxygen scavenging capacity as is described in the examples section of this specification. When prepared by the reactive extrusion, an additional reason to limit the amount of the functionally finished polyolefin oligomer is to avoid excessive drops in the molecular weight of the copolymer compared to the molecular weight of the starting polyester from which the polyester segments are derived. The formation of the copolymer by reactive instruction and transesterification with inevitably leads to the fracture of the molecular chains of the polyester during the insertion of the polyolefin oligomer segments and the reduction of the molecular weight of the copolymer below that of the original starting polyester. Subsequent manufacturing steps can be hindered by low melt strength of the copolymer. For applications that do not require clarity, the charge of the functionally terminated polyolefin oligomer to levels in excess of 8% by weight are acceptable depending on the requirements of the end use application associated with rigidity, process stability and oxygen uptake. As noted previously, a main use in these copolymers is in molded or blown beverage bottles. An intrinsic viscosity of about 0.5 is generally required for the oxygen scavenging copolymers to be suitable for processing in bottles. Preferred methods of using these copolymers in bottles is either as an intermediate layer between two layers of the unmodified polyester or an additive concentrate (blend) with unmodified polyester. Both of these modalities serve to overcome any of the potentially low intrinsic viscosity considerations. Alternatively, when made by reactive extrusion, it may be desirable to modify the intrinsic viscosity of the copolymers. The intrinsic viscosity of the copolymers can be modified in a more advantageous manner using the copolycondensate branching agents. Preferred branching agents include trimellitic anhydride, aliphatic dianhydrides and aromatic dianhydrides. Pyromellitic dianhydride is the especially preferred crosslinking agent because it reacts rapidly and terminates with polycondensates and also because it is readily available commercially. When used, these branching agents are normally employed in the extruder in an amount sufficient to obtain the desired intrinsic viscosity of the copolycondensates, typically in amounts of up to 5,000 ppm (0.5%) with a preferred range of 0 to 3,000 ppm. Alternatively, the copolycondensates of this invention can be prepared via continuous and / or batch techniques at higher molecular weights and higher intrinsic viscosity. Other additives that may also be present in the copolycondensates of this invention include thermal stabilizers, antioxidants, dyes, crystallization nucleation agents, blowing agents (when foam is needed), fillers, accelerators of biodegradation. Few, if any, of these typical additives are used for bottle applications that require clarity. However, as will be appreciated by those skilled in the art, the inclusion of these additives produces copolymers that are within the spirit of this invention. The copolymers of this invention are also suitable for use in opaque applications such as copolycondensate, crystalline, opaque, rigid trays, which will contain low levels of crystallization nucleation agents such as polyolefins. Also, the copolymers of this invention could be used to make cell structures where the copolymers would be foamed at a lower density which serves to further reduce the cost of the container. For opaque applications, the blends of the copolycondensates of this invention will be useful in selected packaging uses, and in these cases the physical blends of the oxygen removal copolycondensates having very large polyolefin oligomer segments could be tolerated. Typically, the mixing of the copolymers of this invention will be with other polycondensates, especially polyesters. However, immiscible mixtures may still be suitable for applications where clarity is not of interest. When prepared by transesterification in a reactive extruder as described above, the copolycondensates of this invention are typically first granulated and then processed into bottles or films. The preferred time of construction of film or bottle wall comprises a three layer mode as shown in Figure 1. While the embodiment of Figure 1 may require special extrusion equipment, it is still preferred for the following reasons: (1) it creates a structure with a relatively thick layer of polyesters since it serves as a good passive barrier to oxygen from the air, (2) the inner layer in contact with packaged material is also polyester that has a long history of use and acceptance for the packaging of consumable materials, (3) the placement of the copolycondensates of this invention between two layers of unmodified polyester with good passive barrier properties, isolating the oxygen elimination copolymers from direct contact with air or oxygen and retains its oxygen scavenging capacity by being applied only to the oxygen passing through the unmodified polyester layers, and (4) the copolycondensates and unmodified polyester are of such similarity that they bind together when they are co-extruded without the need to use an adhesive bonding layer. The preferred three-layer embodiment described above is more easily accomplished by extruding a copolymer layer with the two unmodified PET layers. The copolymer is too chemically similar to the unmodified PET that the three layers were uniformly given to each other and form a monolithic structure in the cooling. No tie layer adhesives are required. However, even in the articles of manufacture of this invention when recycling is not important, additional non-polyester layers can be incorporated to improve adhesion, to improve barrier properties, to reduce costs. It may also be possible to achieve the preferred three layer embodiment by techniques other than coextrusion such as by coating with solutions or thermal function of the separated layers. Any method other than co-extrusion can have disadvantages -from (1) reduction of the elimination potential by unwanted and / or inadvertent exposure of the oxygen scavenging copolymers to air or oxygen, and (2) additional processing steps. For bottle making, the bonding of the three layers by adhesives would work against the target of recycling capacity unless the adhesive was PBD-based or PET-compatible. For the production of films and packaging, recycled capacity is not as important a consideration as it is for bottles. In fact, for films, it may still be desirable to use copolymer layers of this description in conjunction with layers of some materials such as polyethylenevinyl alcohol layers and polyolefin layers. While the immediate co-extrusion of these copolymers may be the most preferred use for them, other use options are also available. For example, the copolymers can be mixed as a concentrate with another PET or polyester for films or bottles, or can be used as an inner liner or layer in a multilayer construction direction, for example, in the packaging of electronic components. When desired for certain applications, methods are available to make even more effective the oxygen scavenging properties of these copolymers. For example, an oxidation catalyst could optionally be added to the copolymer during manufacturing cap of the product. The presence of this catalyst when used in the range of 10 to 2,000 ppm serves to facilitate the rate of oxygen uptake. Preferred catalysts are multivalent transition metals such as iron and manganese. Cobalt is especially preferred. The copolymers of this invention can be used in conjunction with other systems that consume oxygen. for example, an embodiment for improved oxygen removal for products manufactured of this invention comprises the optional inclusion of photoactivators (such as small amounts of benzophenone) in the products manufactured together with the copolymers of this disclosure. Manufactured products, such as bottles, containing the optional photoactive materials as well as the copolymers of this disclosure will be exposed to sufficient UV light to activate the photoactive materials towards the admission of oxygen before use (i.e., filled with fruit juice), or the shipment of the manufactured product. In yet a different, improved embodiment, additional oxygen scavenging materials are deployed within the package cavity together with the use of the copolymers of this disclosure which will comprise the packaging material. Normally, these additional oxygen scavengers will take the form of an envelope, especially for oxygen sensitive, non-consumable materials, such as electronic components. For oxygen sensitive substances, consumables, additional oxygen scavenging materials can take the form of a sphere as is often used in butcher shops under a cut of meat or poultry meat. Since there is no need for clarity or rigidity in the part of these additional, internal oxygen scavengers, it can be economically advantageous to use substances that do not have clarity as a limitation resulting in copolymers that may be opaque. In these applications, the diameter of the polyolefin oligomer segments, of the oxygen scavenging copolycondensate is not critical. There are also embodiments of this technique in which the additional oxygen scavenger employed is one that is a completely different system than the copolycondensates of this invention. In yet another improved embodiment, the copolymers of this disclosure are deployed as an internal can liner along or along with known can liner polygons. In any situation, both passive and active oxygen barriers are present since the pot itself is a passive barrier to oxygen. In any case, the copolymers of this extrusion are prepared to comprise a thermosetting resin, or resin mixture, which could be spray coated onto the inner walls of the container. A sprayable resin could be made more easily by mixing a small amount of a copolymer of this invention with a thermosetting resin normally used to coat cans. It may be necessary to prepare the copolymer with a higher percentage of PBD oligomer segments than what is used for clear copolymers to require only a minimal amount of the copolymer mixed with the spray resin. The orifice of a can liner comprising an active oxygen scavenger is that it gives the opportunity to dissipate the so-called "oxygen" from the canister's free space. "Oxygen from the free space is unwanted oxygen trapped in the vessel during the process. of filling and sealing As it has already been indicated in several cases, the recycling of the bottles made using the copolymers of this description is an important inventive aspect of this description.In addition, the bottles manufactured must be suitable for recycling with other bottles of polyester without the need for any further processing such as delamination or depolymerization A quick review of the materials present in the manufactured bottles of this invention shows how the recycling requirements have been met Figure 1 shows a cross section of the construction Preferred of the bottle wall In Figure 1, layers 26 and 28 are comprised of this r of packaging polyester, not modified, such as PET. The outer surface 24 is defined by the thicker layer of polyester and the inner surface 22 (ie packaging or bottle cavity) is defined by the thinnest polyester layer. The intermediate layer 30 is comprised of the oxygen scavenging copolymers of this invention. For a typical single service juice bottle of approximately half a liter capacity, the oxygen removal copolymer layer of the bottle represents about 5% by weight of the entire bottle. The remaining 95% of the bottle and unmodified polyester, usually PET. Under the heaviest loading conditions of the copolymer with 12% polyolefin oligomer acid, the copolymer layer is still 88% by weight of PET segments and is typically 96% by weight PET when the most preferred percentages of polyolefin oligomer segments are employed. This means that the final bottle, manufactured is at least 99.45% by weight of PET, and typically 99.8% by weight of PET. It is this high percentage by weight of the manufactured bottle that makes it suitable for recycling with other PET or polyester bottles. The main application of the oxygen scavenging copolymers of this description will be the manufacture in packaging walls and packaging articles previously cited in several instances of this description. A main use for these manufactured articles comprises the packaging of perishable foods and perishable items. A non-limiting list of perishable items particularly pleasant to the packaging described in this description will include dairy products such as milk, yoghurt, cream ice cream and cheeses, prepared foods such as stews and soups, meat products such as hot sausages, cold cuts, chicken and beef jerky. Individual service items such as pre-cooked meals and precooked entremeses. Ethnic offerings such as pasta and spaghetti sauce, condiments such as barbecue sauce, ketchup, mustard and mayonnaise, beverages such as fruit juice, wine and beer, dry foods such as dried fruits, dried vegetables and breakfast cereals, baked goods such as bread, cookies, pasta, biscuits and buns, sandwiches such as candy, chips and sandwiches filled with cheese, spreads such as peanut butter, and gelatinous combinations, jams and gelatins, and seasonings either dry or fresh. In general, the described copolymers and the package made thereof can be used to improve the barrier properties of the packaging materials proposed for any type of product, be it food, beverages or otherwise, which degrade in the presence of oxygen.

EXAMPLES PREPARATION OF COPOLYMER The copolymers referred to in all subsequent examples, unless otherwise indicated, were prepared in the manner as described herein. A ZSK-30 extruder was equipped with a feeder of low-weight PET pellets under a blanket of nitrogen. The hydroxy-terminated polybutadiene was kept in a viscous fluid container from which it was transported separately via a positive expressing pump to a vacuum suction port in the extruder line. The PET was extruded at a feed rate of about 8 pounds (3.6 kg) per hour giving a residence time of about 4 minutes while being maintained at a temperature in the range of 260 to 270 ° C. The hydroxy-terminated polybutadiene (RLM20 Elf Atochem, MW of 1230 or RHT45 MW of 2800) was pumped into the extruder at variable speeds to give the percentages by weight in the range of 2% to 8% for the hydroxy-terminated polybutadiene in the zone of mixing the extruder. Fusion seal designs were used to affect a vacuum zone after the mixing zone prior to opening the nozzle. The extrudates were dried and did not smoke, and were easily granulated after rapid cooling in a water bath. No surface film (slippery hydrocarbon surface) could be seen at all in the water bath, indicative of copolymer formation by transesterification during relative extrusion. The appearance of a film in the water bath will have indicated the presence of an unreacted polyolefin oligomer. Cobalt octoate (Hulls Nuodex® DMR cobalt 6%) was used at a sufficient treatment rate to give 50 PPM of Co when the 2% by weight hydroxy-terminated polybutadiene and 200 PPM of Co were used when the polybutadiene was used. hydroxy at 8% by weight. The inclusion of cobalt octoate did not adversely affect the clarity of the treated copolymers. To the extent that was measured, the cobalt-containing copolymers appeared to have slightly improved clarity. Extruded products prepared as described were characterized as copolymers by various analytical techniques as described in Examples 1 to 11. All copolymers prepared by the method described above have individual vitreous transition temperatures (Tg) in the range of 62.0 °. C at 72.9 ° C. All copolymers prepared by the method described above were suitable for melt processing and capable of bottling processing according to the preferred three-layer bottle wall embodiment. In the following examples, all data relating to the oxygen scavenging capacity was taken either at 22 ° C or 60 ° C, which is below the glass transition temperature of the copolymers of this invention.

EXAMPLES FROM 1 TO 8 Examples 1 to 8 are shown in Table 1 and relate the inherent viscosity losses (IV) found as expected in the transesterification formation of the copolycondensates by reactive extrusion of a mixture of PET and PBD oligomers, terminated in hydroxy. The values of I.V. in Table 1 they are expressed in deciliters per gram (dl / g). The I.V. the D2857 method was measured by the inherent viscosity technique of polyesters and polyamides based on ASTM and the solvent used was a 60/40 mixture of phenol / 1,2,1-tetrachloroethane. The low molecular weight PBD oligomers (LMW) which have a high content of hydroxy end groups changed the I.V. additionally from the start value of 0.67 for PET than the oligomers of high molecular weight PBD (HMW) at the same loading level. The gel permeation chromatography (GPC) data taken from Examples 2, 3, 6 and 7 (data not shown) confirm the changes in the complete molecular weight distribution corresponding to the changes in I.V. predicted by the Mark-Hou ink cure that relates the molecular weight to I.V. Only the formation of a true copolymer via transesterification will produce this result. The PET used for the two control samples and also used in the formation of the copolycondensates was Shell Clear TufR 7207. A photomicrograph with a transmission electron microscope (TEM), for an accretion of 60,000 of a sample that was prepared identically to the copolymer of Example No. 5 is shown in Figure 2. The copolymer was stained with Os04 which obscured only the polyolefin oligomer segments of the copolymer . The size and approximate distribution of the polyolefin oligomer segments are easily discernible.

TABLE 1 CHANGE OF INHERENT VISCOSITY - EXAMPLES 1 TO 8 EXAMPLES 9 TO 11 Figures 3 to 5 cover Examples 9 to 11 respectively and show the data obtained by transmission electron microscopy (TEM) technology. What is shown are the distribution of the sizes of the polyolefin oligomer segments for the condensation copolymers of this invention. The copolymers have been stained with Os04 which adds color only to the unsaturated segments of polyolefin oligomer. The copolymer of Example 11 was prepared in the manner as described above. The copolymers of Examples 9 and 10 were prepared in a manner similar to that described above except that the extrusion rate was 20 pounds / hour (9.9 kg / hour) for Example 9 and 12 pounds / hour (5.4 kg / hour) for Example 10. The three examples show the effect on the size distribution of the polyolefin oligomer segments at three different PET extrusion rates of 20 pounds / hour (9.1 kg / hour), 12 pounds / hour (5.4 kg) / hour), and 8 pounds / hour (3.6 kg / hour). These extrusion rates gave a residence time in the extrusion of about 3 to 5 minutes. In all three cases, 4% of hydroxy terminated PBD (approximately 1230 MW) was copolymerized by extrusion with PET. For each of the copolymers of Examples 9-11, 16 photomicrograph plates at an increase of 60,000 were prepared in a manner similar to the partial plate of Figure 2. Figure 2 shows a cross-sectional cut and a copolymer film Identically prepared to that of Example 5. The 16 frames or structures for each of Example 9, 10 or 11 (which are also cross sections of the sheets, in Figure 2) were then subjected to an automated process which first estimated a average diameter for each segment in each plate and then subsequently calculated an average cross-sectional area for each segment in the plate on the assumption that each segment is approximately a circle. The process also collected segments of similar size into groups that cover a convenient wavelength range and accounted for the number of segments that fall in each grouping. The wavelength range for the clusters was greater at shorter wavelengths to fit an exponential display of segment size.

For each graph of Figures 3-5, the X axis shows an average diameter size (per group) of the polyolefin segments in nonameters (nm, 1 x 10"9 meters.) One nm equals approximately 10 Angstrom units For example, 300 nm is equivalent to approximately 3,000 units of Angstroms.The Y axis of Figures 3-5 shows the area of the segments (in square nm) multiplied by the number of segments in that area, that is, (the number in each group) per frame It is convenient to characterize the distributions of segment sizes using bar graphs and also to add the total length of all bars in any given graph For this invention, when the sum of the lengths of all bars at 300 nm or less exceed 50% of the sum of the total of all bars, the size distribution of the segments is considered to be considerably less than 300 nm (3,000 units of Angstrom). preview It is preferred that the distribution of polyolefin segment sizes be predominantly (as defined above) below 3,000 Angstroms when clarity is a significant amount required of the copolymers of this invention. In general, segment sizes greater than about 1,500 nm will not disperse light that is significantly visible (ie, interfere with clarity) and will be ignored in previous considerations and calculations. As can be seen from these examples, the most favorable distribution of the sizes of the polyolefin oligomer copolymer segments (ie, predominantly smaller diameters that do not interfere with the considered and general visible light which is in the range of approximately 400 nm to approximately 800 nm) occurs at lower extrusion production rates. Based on your results, a similar defect will be expected for the Hydroxy-terminated PBD, of higher molecular weight (MW of approximately 2800), that is, lower production rates (longer residence time) will produce more favorable diameter diameter distributions of polyolefin oligomer segments with predominantly smaller diameters that do not interfere with visible light.

EXAMPLES 12 TO 15 The data for Examples 12 to 15 can be found in Figure 6. These four examples show as the oxygen scavenging capacity of copolymers of this invention at two PBD values and at two temperatures. Example 12 is data for a biaxially oriented film of two thousandths of thickness constructed from a copolymer of 4% PBD terminated in hydroxy PBD (MW, approximately 1230) and extruded PET at a production rate of about 8 pounds ( 3.6 kg) per hour. Also, for Example 12, 10 grams of the copolymer film in contact was placed with 500 ce of air and the oxygen percent of air inspected with a Mocon HS750 analyzer unit for a period of days at 22 ° C. for Example 13, all parameters were the same as for Example 12 except that the test was run at 60 ° C. Example 14 was the same as Example 12 except that the MW of the PBD was about 2,800. Example 15 was the same as Example 14 except that the test was run at 60 ° C. As can be seen from the graph in Figure 6, the PBD of PM 2800 is a much more effective oxygen scavenger than the PBD of PM 1230 at an ambient temperature of 22 ° C although both examples are at a PBD level of 4. %. The degree of biaxial orientation imparted to all of the examples 12 to 15 was an elongation of the sheets 2.5 times in one direction of the plane of the sheet (for example, along axis 5 of Figure 2) and 4.0 times in one direction. direction of the plane of the sheet, at 90 ° from the elongation of 2.5 ve ce s (for example, Y axis in Figure 2). This degree of biaxial orientation is common in the bottling industry and is often referred to as a 2.5 x 4.0 biaxial orientation. Also shown in Figure 6 is the data for a control sample consisting of 25 grams of modified PET in the form of pulverized pellets held at 60 ° C. The unmodified PET control showed no oxygen removal capacity at 60 ° C at all.

EXAMPLE 16 AND 17 In addition to the oxygen scavenging capability at room temperature, the molecular weight of PBD also had an effect on the absolute clarity / clarity of the copolymers. Figure 7 shows the data for Examples 16 and 17. 'Example 16 was a biaxially oriented (biaxial orientation 2.5 x 4.0), 2 mils (0.0051 cm) thick sheet, of the copolymer consisting of PET and 4 % of PBD of molecular weight of 2800. Example 17 was the same as Example 16 except that the molecular weight of PBD was 1230. The measurements of clarity in terms of the percent of light transmission for various wavelengths of the Luminous energy was measured in a 'Shimadzu UV-160 spectrophotometer. Clarity was improved for the lower molecular weight PBD of Example 17 at all wavelengths indicating that when clarity is an important consideration, it may be necessary to balance the improved oxygen scavenging capacity of the high molecular weight PBD against the best light transmission properties of the lower molecular weight PBD.

EXAMPLES 18 AND 19 The clarity of the copolymers of this invention when used in film sheets is also affected by the degree of imparted orientation of the film sheets. The data for examples 18 and 19 are shown in Figure 8. Clarity measurements in terms of the light transmission percent for various wavelengths of light energy were measured on a Shimadzu UV-160 spectrophotometer. Example 18 was for a sheet 2 mil (0.0051 cm) thick film of the copolymer comprising predominantly PET segments and 4% by weight of PET segments of molecular weight of 1230. The sheet of Example 18 was totally unoriented. Example 18 was prepared identically to the copolymer used above for Example 5 and is also shown in Figure 2. Example 19 was identical to Example 18 except that the film sheet for Example 19 was biaxially oriented (biaxial orientation 2.5 x 4.0) and was selected to be 2 mils (0.0051 cm) thick after biaxial elongation. The film biaxially oriented to Example 19 showed improved clarity particularly in the wavelength range of 400 to 700 nm. An explanation and arrangement of these reasons that the biaxially oriented film was more transparent than the non-oriented film is difficult since there are a number of factors involved. The diameters of the cross sections of the polyolefin segments increase along the X and Y axes (See Figure 2) but the size of the cross section in the direction of the Z axis, which is also the orientation of the travel of the light, actually decreases the biaxial elongation. It is believed by applicants that this decrease in segment diameter in the direction of light travel changes the distribution of segment sizes even more predominantly below 3,000 Angstroms units. It is further believed that the large size of the segment diameters along the X and Y axes after biaxial elongation has little effect on dispersion of use.

EXAMPLES 20 TO 22 The clarity of the copolymers of this invention is an important consideration for the construction of bottles, especially in terms of the clarity of the copolymer when comparing an unmodified polyester. Example 21 in Figure 9 shows the admission of clarity in terms of the percent of light transmission for various wavelengths of light energy as measured in a Shimadzu UV-160 spectrophotometer. The example 21 was a biaxially oriented film (biaxial orientation 2.5 x 4.0) 2 mils (0.0051 cm) thick of a copolymer that was 96% by weight PET and 4% by weight PBD of 1230 molecular weight extruded at 8 pounds / hour (3.6 kg / hour) . Example 20 was a control consisting of unmodified PET also used in the form of a biaxially oriented film, 2.5 x 4.0, 2 mils (0.0051 cm) thick. As can be seen in the data, the copolymer clarity for visible light (generally considered to be 400 to 800 nm) or at least 70% for the clarity of the unmodified PET. Example 22 was a theoretical calculation for the predicted light transmission percent of the copolymer at a thickness of 1 mil (0.0025 cm) and was included to show predicted clarity at a lower terminal use level in terms of the thickness of the the bottle wall.

EXAMPLES 23 TO 26 The inclusion of a transition metal catalyst in the copolymers of this invention dramatically influences the rate at which oxygen was removed. The data associated with Examples 23 to 26 are presented in Table 2 and clearly show these effects. Examples 23 to 26 were prepared in the manner described above except that they were samples taken from a larger run of pilot plant and were not subjected to cooling with water. In contrast, after leaving the extruder, the copolymer was left in a Sandvik metal band for cooling prior to chopping / granulation. The copolymer of Examples 23 to 26 was made by extrusion copolymerization using 4% by weight of PBD of MW of about 1230 and 96% by weight of PET. The granules were contained in heat-sealed metallized bags for storage before use. Granules were milled prior to compression molding in 20 mil sheets (0.051 cm) thick which finally were biaxially lengthened in the same way as described in the previous examples in sheets of 2 mils (0.0051 cm) thick. For the Examples 24 and 26, the Huhls Nuodex.RTM. D.M.R. (cobalt 6%) dissolved in mineral spirits was added to the ground copolymer in sufficient quantity to achieve 150 PPM of cobalt. No cobalt was added to Examples 23 and 25. For all Examples 23 to 26, 10 grams of the biaxially oriented film were exposed., of 2 thousandths of an inch (0.0051 cm) of thickness, to 500 ce of air with periodic inspection of the percentage of air that remains in the sample of 500 ce of air using a Mocon HS750 750 analyzer. The results obtained for these four examples are shown in Table 2 below. Examples 23 (non-cobalt) and 24 (150 PPM cobalt) were run at room temperature of 22 ° C and should be compared with each other to see the effect of the presence of cobalt. It is pointed out that the data for day 42 showing only 3.98% remaining oxygen with cobalt (Example 24) versus 19.9% remaining oxygen for the same copolymer without cobalt (Example 23). Also for day 42, the oxygen removed with cobalt was 8.3 cc per gram of copolymer against only 0.4 cc of oxygen removed per gram of cobalt-free copolymer. It should be noted that the value of 0.4 cc of oxygen per gram of copolymer seems to be hardly the threshold requirement, but the value was approximately the same as that found at 22 ° C for a commercially available oxygen scavenger used without cobalt (see Example 27). A similar effect was seen when Examples 25 (non-cobalt) and 26 (150 PPM cobalt) were compared, but the improvement when adding cobalt was not as dramatic due to the increased rate of oxygen removal of the copolymer at 60 ° C. still without cobalt. Figure 10 shows the data of Table 2, below, corresponding to Examples 23-26 in graphic format.

TABLE 2 EFFECT OF COBALT ON THE ELIMINATION OF OXYGEN FROM THE COPOLYMER EJ 23 EJ 24 EJ 25 EJ 26 TEMPERATURE 22 22 60 60 DAY 0 - PERCENT OF 02 20.9 20.9 20.9 20.9 DAY 3 - PERCENT FROM 02 20.7 - 16.6 - DAY 7 - PERCENT FROM 02 20.5 11.8 8.02 5.84 DAY 14 - PERCENT OF 02 20.4 9.49 3.67 1.42 DAY 21 - PERCENT OF 02 20.3 7.41 2.49 0.646 DAY 28 - PERCENT OF 02 20.1 5.32 2.02 0.478 DAY 42 - PERCENT OF 02 19.9 3.98 1.09 0.006 DAY 0 - ADMISSION IN 0.4 8.3 9.3 10.3 CC / GRAMOS EXAMPLES 27 TO 30 The data for Examples 27 to 30 are displayed in graphical format in Figure 11. Examples 27 to 30 show the superior oxygen scavenging capacity of the copolymers of this invention against a frequently marketed FERERIDO system such as the Carnaud Metalbox system (CMB). ) OxBar. The CMV oxygen scavenging system comprises a mixture of about 96% PET and about 4% poly (m-xylenamidapine) which is a polyamide made up of equimolar amounts of 2 (1) metaxylene-diamine monomers and (2) acid adipic This polyamide is often referred to as MXD-6. U.S. Patent No. 5,032,515 discloses the CMB 's OxBar oxygen scavenging system in detail. Example 49 was prepared as 4% by weight of MXD-6 mixed with 96% by weight in PET and also containing 200 PM of cobalt which is a preferred method of use according to US Patent No. 5,021,515. This CMB polymer mixture was tested for oxygen admission in a manner similar to that given for Examples 23 to 26 above, in 10 grams of biaxially oriented 2 mil film (0.0051 cm) thick, they were exposed to 500 ce of air with periodic inspection of the percentage of air remaining in the 500 ce air sample using a Mocon H750 analyzer. The CMB mixture designated as Example 27 was tested at 22 ° C. When the calculations were made, Example 27 had an oxygen scavenging capacity of 0.41 ce of oxygen per gram of copolymer at 22 ° C in the absence of cobalt. Example 28 was the same as Example 27 except that it was tested for oxygen admission at 60 ° C. Examples 29 and 30 are copolymers of this invention, which comprise both predominantly PET segments and 4% PET of molecular weight 1230 with 150 PPM of cobalt present. Example 29 was tested for oxygen admission at 22 ° C and Example 30 was tested at 60 ° C. Examples using the copolymers of this invention have less cobalt (150 PPM) than the PET / MXD-6 system having 200 PPM of cobalt. Also, a less effective oxygen removal PBD with molecular weight of 1230 (see Examples 12 to 15, see Figure 6) was used for the copolymers of this invention. Despite these factors favoring the PET / MXD-6 system, the copolymers of this invention were far superior in terms of oxygen admission at both tested temperatures as can be easily discerned from the graphs in Figure 11.

EXAMPLES 31 AND 32 Examples 31 and 32 show unexpected and surprising results obtained with respect to the oxygen scavenging capacity and the efficacy of the copolymer compositions of this invention. It was noted earlier in this explanation that applicants believe that substances that have secondary and tertiary nitrogen atoms will make good candidates for oxygen removal. Before it was selected as a preferred hydrocarbon for oxygen removal, tests and calculations were done to differentiate the intrinsic oxygen removal capacity of the oligomeric PBD and also to stimulate its theoretical thermodynamic oxygen removal capacity. Example 31 (two separate runs of identical samples) consisted of 0.4 grams of hydroxy-terminated PBD of MW of 1230 which was heated to about 270 ° C under a nitrogen atmosphere and kept at its temperature for about 4 minutes as an emulation to extrusion. Example 32 (three separate runs of identical samples) consisted of 10 grams of a copolymer of this invention comprising segments of the PET and 4% by weight of segments of PBD (MW of about 1230). For each of the three samples of Example 32, 10 grams of copolymer were used which at the 4% loading level provided the same amount of PBD as Example 31, ie, 4% of 10 grams of copolymer gave 0.4 grams of oligomeric PBD. Five samples of Examples 31 and 32 were placed in 500 cc containers, sealed completely in the environment, and then kept at 60 ° C for a period of days. During this time, the percent of air oxygen within each of the sealed containers approached with a Mocon HS750 analyzer unit and was periodically recorded. The results are shown in Figure 12. The same amount (weight) of hydroxy-terminated PBD was dramatically more effective as an oxygen scavenger after it was converted to segments of a copolymer than when used as a viscous fluid. This was irrefutable evidence that the incorporation of the hydroxy-terminated PBD into a copolyester produced a useful composition and provided a very effective means that improved the oxygen scavenging capacity of the hydroxy-terminated polyolefin oligomer substantially beyond its capacity as is commercially available. available. In Figure 6, it is signaled that PET has no oxygen elimination capacity at all. Example 31 demonstrates that the hydroxy-terminated PBD was a poor oxygen scavenger when used as commercially available. In this way, none of the two starting materials, PET and PBD finished in hydroxy, were powerful eliminating substances. However, however, when the two starting materials were formulated into the copolymers of this invention, the result was a truly outstanding composition capable of removing oxygen at capacities and speeds required for commercial application. Despite the reason for this behavior of the starting materials, the thermodynamic potential for oxygen removal of the oligomeric PBD was only realized after it was made in a copolycondensate of this invention. Examples 1 z 32 above illustrate the improved properties of the compositions described, methods for preparing the compositions, and the usefulness of the compositions and are not proposed to limit the scope of the invention as defined herein. It will be understood by those skilled in the art that oxygen scavenging compositions will be useful in a wide variety of packaging constructions which, despite variations in resin composition, configuration of the final use layer, and other aspects, will incorporate However, the benefit of the present invention. In addition, while only copolyesters have been exemplified in this specification, those skilled in the art will appreciate that polyolefin oxygen scavenging oligomers that are functionally terminated with terminal copolycondensation functional groups can be easily incorporated into other copolycondensates such as copolyamides, copolyimides , copollisons, copolyoles, copolyoethers, copolyetones, giving oxygen scavenging properties to these additional copolycondensates prepared by the present invention. It is noted that in relation to this date, the best method known by the applicant to carry out the present invention is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property:

Claims (19)

1. Polycondensation copolymers capable of absorbing oxygen in the solid state at temperatures below their glass transition temperature, characterized in that they predominantly comprise polyester segments and an oxygen removal amount of polyolefin oligomer segments, wherein the polyol oligomer is is selected from the group consisting of polypropylene, poly (methyl) 1-pentene, unhydrogenated polybutadiene, and mixtures thereof, and wherein the molecular weight of the polyolefin oligomer is in the range of 100 to 10,000.

2. The copolymers according to claim 1, characterized in that the polyolefin oligomer comprises unhydrogenated polybutadiene.

3. The copolymers according to claim 1, characterized in that the molecular weight of the polyolefin oligomer is in the range of 1,000 to 3,000.

4. The copolymers according to claim 1, characterized in that the polyolefin oligomer segments have a cross-sectional size distribution predominantly less than about 3000 units of Angstroms.

5. The copolymers according to claim 1, characterized in that, after a 2.5 x 4.0 biaxial orientation, in a film of 0.0025 to 0.025 centimeters (1 to 10 thousandths of an inch) in thickness, they have a transparency of at least 70% from that of similarly oriented films and the same thickness of the unmodified polyester from which their polyester segments were derived, and wherein the 70% transparency is in the light wavelength range of 400 to 800 nm.

6. The copolymers according to claim 1, characterized in that the polyolefin oligomer segments comprise from 0.5 to 12% by weight of the copolymer.

7. The copolymers according to claim 1, characterized in that the polyolefin oligomer segments comprise from 2 to 8% by weight of the copolymer.

8. The copolymers according to claim 1, characterized in that the polyester segments comprise repeat units selected from the group consisting of those encompassed by Formula IV and Formula v, and wherein n in each of Formulas IV and V have value in the range of 2-4. Formula [V Formula

9. The copolymers according to claim 1, characterized in that, in the solid state at ambient temperatures of 0 ° C to 60 ° C, they exhibit an oxygen absorption capacity of at least 0.4 cc per gram of copolymer.

10. The copolymers according to claim 1, characterized in that they also comprise an oxidation catalyst.

11. A method for protecting oxygen sensitive substances from oxygen degradation, characterized in that it comprises packaging the oxygen sensitive substances in a suitable article of manufacture comprising the copolymers of claim 1 in an amount sufficient to serve as an oxygen barrier.

12. The method according to claim 11, characterized in that the article of manufacture further comprises a transition metal catalyst that serves to facilitate the rate of oxygen admission.

13. The method according to claim 11, characterized in that the article of manufacture also comprises photoactive materials capable of admitting oxygen in the irradiation with sufficient UV light to activate them and improve the speed of admission of oxygen.

14. Oxygen barrier vessels characterized in that they comprise one or more layers of the copolymers of claim 1.

15. The containers according to claim 14, characterized in that they comprise an inner layer of the copolymers of claim 1, wherein the inner layer is sandwiched between the polyester layers.

16. The containers according to claim 14, characterized in that the copolymer comprises polyester segments derived from the groups consisting of PET and PEN.

17. Oxygen barrier containers, characterized in that they comprise the copolymers of claim 1 mixed with polycondensates.

18. Oxygen barrier packaging materials, characterized in that they comprise one or more layers of the copolymers of claim 1.

19. The packaging materials according to claim 18, characterized in that the copolymer comprises polyester segments derived from the group consisting of PET and PEN. SUMMARY OF THE INVENTION Compositions for the removal of oxygen are described. These compositions comprise condensation copolymers comprising predominantly polyester segments and an oxygen scavenging amount of polyolefin oligomer segments. The polyester segments comprise segments derived from typical bottling and packaging polyesters such as PET and PEN. The copolymers are preferably formed by transesterification during reactive extrusion and typically comprise about 0.5 to about 12% by weight of segments of the polyolefin oligomer. The copolycondensates are capable of absorbing at least 0.4 ce of oxygen per gram of copolymer in the solid state at ambient temperatures and are typically used as capable in films, photos, cups, wraps, bottles, etc. The use of these oxygen scavenging compositions in bottles provides a clear and rigid bottle similar in appearance to unmodified polyester bottles. In a series of preferred embodiments, the bottles made with the oxygen scavenging copolycondensates of this invention are greater than 99.4% by weight of polyester and suitable for recycling with other polyester bottles.