HUP0200350A2 - Transparent oxygen-scavenging article including biaxially-oriented polyester - Google Patents

Description

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TRANSPARENT, OXYGEN-ABSORBING PRODUCT CONTAINING BI-DIRECTIONALLY ORIENTED POLYESTER

The present invention relates to oxygen-absorbing materials and packaging materials for storing oxygen-sensitive products. More particularly, the present invention relates to a transparent article incorporating an oxygen-absorbing aromatic ester polymer and a bidirectionally oriented polyester, which article is suitable for protecting oxygen-sensitive products from deterioration.

Plastic packaging has undoubted advantages over glass and metal packaging, such as low weight, variability in packaging appearance, non-fragility and low manufacturing cost. However, plastic packaging can have a higher permeability to certain gases (oxygen and carbon dioxide) and liquids (water) than glass or metal; these gases/liquids penetrate the plastic and reduce the shelf life of the product stored in it. Various special plastics and layer structures have been developed to provide acceptable shelf life and commercially acceptable plastic protective packaging for certain oxygen-sensitive products such as fruit juice and ketchup.

There are two general types of oxygen barrier materials - active and passive. For example, multilayer technology allows the incorporation of thin layers of expensive barrier polymers (such as polyvinylidene chloride copolymer (PVDC) or ethylene vinyl alcohol (EVOH)) or thin metal film layers with structural layers of commercially available plastic resins such as polyethylene terephthalate (PET).

In an “active” protection system, an “oxygen scavenger” is incorporated into the single- or multi-layer plastic structure to, on the one hand, consume the initially present or generated oxygen from inside the packaging,

89581-6918 TEL/cov

- 2 at the same time prevents external oxygen from entering the packaging. Thus, oxygen absorbers not only remove oxygen from the inside of the packaging, but also prevent it from entering the packaging.

Another important design parameter for oxygen barrier packaging is heat resistance. The product often needs to be “sterilized” in a process in which the package is exposed to high temperatures and/or pressures. For example, in a typical “hot-fill” process, the product (e.g., juice) is at 80-85°C when it is introduced into the container, the container is sealed (capped), and the juice/container is allowed to cool. The container must withstand both the hot-fill temperature and the vacuum that is created in the sealed container as the product cools without deformation. Commercially successful hot-fill juice containers have been developed by Continental PET Technologies, Inc. of Bedford, New Hampshire, which offer a 1.5- to 4-fold improvement in oxygen barrier properties over conventional single-wall PET containers. These multi-layer juice containers contain two very thin interlayers of EVOH sandwiched between the inner and outer layers of virgin PET and a base layer of either virgin or recycled PET.

However, there are products that are even more “oxygen sensitive” than fruit juice. For example, most beers require at least 10 times more oxygen protection than a conventional single-layer PET container provides. Furthermore, most beers are bottled using a “wet pasteurization” process, in which the beer is filled into the bottle at a temperature between -1°C and 7°C, the bottle is sealed, and the sealed bottle is immersed in a 60-75°C bath for at least 10 minutes (Figure 12). This pasteurization can be considered even more degrading than hot-filling, since the bottle is exposed to high temperatures for a much longer period of time.

- 3 effects. The beer is also saturated with carbon dioxide and accordingly the sealed container must hold the liquid under pressure during this extended period of time in the high-temperature bath. Both the increased temperature and pressure exert a tensile force on the container wall, which forces can delaminate the layers in a multilayer container.

Another problem that must be overcome when packaging beer in plastic bottles is the permeation of carbon dioxide (CO2). In order to maintain shelf life, the container must provide a CO2 barrier that minimizes the amount of CO2 escaping from the beer throughout the intended shelf life.

Beer bottling companies are currently investing millions of dollars in wet pasteurization equipment and are therefore reluctant to accept new packaging unless it can withstand the process. A conventional single-layer PET container may not survive the wet pasteurization process and will not provide the necessary barrier properties. The known multi-layer PET/EVOH containers also do not provide the necessary barrier properties for beer at a competitive price.

Attempts have been made to produce single- or multi-layer containers with significantly better oxygen barrier properties and higher heat resistance, including poly(ethylene naphthalate) (PEN) and a polyester similar to poly(ethylene terephthalate) (PET). However, the price of PEN is significantly higher than that of PET, so this cost-effective alternative has not found widespread acceptance.

Furthermore, the materials must be approved by government authorities, such as the U.S. Food and Drug Administration, for use in food packaging. All of these factors, coupled with the higher costs (raw materials and process costs) of commonly used oxygen scavenging polymers, have prevented widespread adoption of plastic beer cans.

- 4 Thus, despite the long-recognized need and the large size of the potential market, there is a continuing pressure to develop plastic closure packaging that meets the stringent temperature, pressure and gas permeability requirements imposed on plastic beer containers.

The present invention provides a transparent oxygen scavenging product comprising a bidirectionally oriented aromatic polyester polymer and an aromatic ester adsorbent polymer. The adsorbent, absorbing polymer comprises α-hydrogen carbonyl groups of the general formula (I), where n = 2 or more, which provide the oxygen scavenging function. The relative weight percent of α-hydrogen carbonyl groups and aromatic groups is selected to provide the desired oxygen scavenging rate and a Tg that allows the polyester to be bidirectionally oriented without substantially losing transparency. The aromatic groups provide single or fused aromatic rings in the main chain or side chain of the oxygen scavenging polymer and preferably comprise one of the groups shown in Figure II in the main chain; and one of the groups shown in Figure III in the side chain.

The article may be a film or a package, or a part thereof; for example, a transversely stretched film and a blown container that undergoes axial and circumferential expansion. The article may be single-layered or multi-layered. The absorbent polymer may be incorporated in a layer separate from the polyester, or may be blended or copolymerized with the polyester.

The present invention provides an absorbent polymer that is compatible with aromatic polyesters such as poly(ethylene terephthalate) (PET) and poly(ethylene naphthalate) (PEN), so that the polyester can be oriented in two directions without loss of transparency. The transparency of a product with a thickness of Ηγ (to be defined later) can be measured in terms of the percentage of haze, which is defined by ASTM

- 5 Measured using a standard color difference measuring instrument according to the Dl003 method. Preferably, the product has a turbidity of less than 10 percent, more preferably less than 5 percent.

The processing compatibility of the scavenging polymer and the polyester is selected based on the glass transition temperatures (Tg) of the two polymers, whereby either the blend, copolymer or separated layers of the polymers can be processed in the same temperature range without loss of transparency, for example the temperature was maintained above the Tg and stretched in the cross direction to achieve bidirectional orientation of the polyester. Preferably, the average bidirectional stretch ratio was 9:1-15:1. The Tg of the scavenging polyester can be adjusted by the aromatic group content of the polymer - increasing the aromatic character increases the Tg.

In general, the Tg of the polymer used in conventional plastic containers should be at least 5 °C above the ambient temperature at the time of use, for example, if a carbonated beverage bottle is used in an environment where the temperature can reach 35 °C, the Tg of the polymer should be at least 40 °C, otherwise the polymer may melt (no longer a solid product). The Tg also defines the temperature above which an aromatic polyester must be heated to be suitable for bidirectional stretching, which orients and partially crystallizes the polymer, giving it adequate structural strength. For example, the Tg of PET is about 70 °C, the Tg of PEN is about 120 °C; To facilitate the process, the polymers are typically stretched at an orientation temperature of at least 20 °C above the Tg (e.g., PET at least 90 °C, PEN at least 140 °C, varying depending on the copolymer content). It is desirable that the Tg of the absorbing polymer be below the orientation temperature of the polyester to be bidirectionally oriented (e.g., PET or PEN), but not so much that the absorbing polymer crystallizes (becomes opaque or opaque) during orientation.

- 6 during the orienting process. The Tg of the absorbent polymer should be at least 10°C below the orientation temperature used for the bidirectional orientation of the polyester. The preferred Tg range for an amorphous absorbent polymer (e.g., having no more than 3% crystallinity under any circumstances) is 0-15°C below the Tg of the polyester, more preferably 3-7°C and particularly preferably about 5°C below it. The preferred Tg range for a crystalline absorbent polymer is 0-15°C above the Tg of the polyester, more preferably 3-7°C and particularly preferably about 5°C above it.

Thus, in order to remain a solid product under generally accepted ordinary conditions, the Tg of the absorbent polymer is at least 40°C, preferably at least 48°C and more preferably 70-135°C. For easier processability with PET polymers, the Tg of the absorbent polymer is 70-85°C and for processing with PEN polymers, 120-135°C. For amorphous absorbent polymers, a lower Tg of 90-100°C is still acceptable for use with PEN polymers.

In general, the relative mole or weight percent composition of the various groups in the selected absorbent polymer is chosen to optimize the required absorbent and compatibility characteristics. Accordingly, increasing the number of α-hydrogen carbonyl groups increases the rate of oxygen absorption. Ester groups (COO) provide compatibility with the polyester. Increasing the number of aromatic groups increases the Tg. Increasing the length of the aliphatic chain (adjacent to the carboxyl group) can increase the oxygen absorption capacity (the absorption performance during the storage time in the container), which is explained below.

Without going into theoretical arguments, we believe that the oxygen-absorbing properties of these polymers result from the presence of carbonyl groups, which act as knots or defect sites to break the equilibrium.

- 7 - · .· · .· ·:

• · · · · · · · · · · · · · · · · · ·· ·* unevenness in the chain of the molecular structure at or near the carbonyl group. It is believed that this unevenness reduces the chemical stability of the hydrogen atoms attached to the atoms in the alpha position to the carbonyl carbon. The result is that the bond strength of these hydrogen atoms is significantly reduced, which makes them much more easily dissociated by diatomic oxygen gas and thus has a relatively high tendency to react with oxygen, resulting in the oxygen-absorbing property.

This is in contrast to previously known oxygen-reactive materials which exploit carbon-carbon double bonds (unsaturation) in the polymer chain. One result is that the oxygen-absorbing polymers of the invention do not need to contain carbon-carbon double bonds in the main chain to achieve gas absorption.

The carbonyl carbon adjacent to the aliphatic chain (e.g., (CH ₂ ) _n ) is believed to provide a site for oxygen consumption in a continuous cascade, as illustrated in the steps of Figures 13A-13K.

In Figure 13A, we start with an ester group that has a 2-carbon aliphatic chain attached to a carbonyl group and an oxygen molecule (0=0) (which it consumes) approaching it.

In Figure 13B, the oxygen molecule has released an alpha hydrogen radical on the alpha carbon atom and as ·0—O—H from the oxygen molecule.

In Figure 13C, the radical of the alpha carbon atom is completed, at least temporarily, by the addition of the ·0—O—H radical. Another oxygen molecule is added to the further reaction and is actually absorbed.

In Figure 13D, the free oxygen molecule releases a second α-hydrogen, resulting in a new radical on the first α-carbon atom and forming a new ·Ο—O—H radical.

In Figure 13E, three reactions occur simultaneously.

1. The H on the free ·0—O—H radical bonds with —O—H

- 8 is coupled to the —O—O—H end attached to the α-carbon atom, resulting in water (circled part in Figure 13E).

2. During the formation of water, the previous free radical ·Ο—O—H becomes a simple 0=0 oxygen molecule.

3. The radical on the α-carbon atom migrates to the bound oxygen atom, forming a double bond (as shown by the arrow).

Figure 13F shows the final stable reactants. The new carbonyl group is in place of the previous oc-hydrogen, a water molecule has been formed, and an oxygen molecule is free again.

In Figure 13G, either this free oxygen molecule 0=0 or any other oxygen molecule releases an α-hydrogen from the newly formed (second) α-carbon atom, forming a radical on the second α-carbon atom and converting a free oxygen molecule into an •O—O—H radical.

In Figure 13H, the oxygen molecule ·0—O—H converted into a radical is attached to the second α-carbon atom, temporarily completing the radicals. Another oxygen molecule is consumed. The water molecule formed from the previous steps is not shown because it does not participate in further reactions.

In Figure 131, the newly arriving oxygen molecule, 0=0, liberates the remaining α-hydrogen, producing a free radical, ·Ο—O—H, and forming a radical on the second α-carbon atom.

Figure 13J again shows a multi-step reaction, similar to Figure 13E, where the —O—H from the —O—O—H group attaches to the second a-carbon atom, forming water, releasing the hydrogen of the free ·Ο—O—H radical. This again produces an 0=0 oxygen molecule. The remaining radical from the second a-carbon atom migrates to the remaining bound oxygen atom, forming a double bond on the oxygen.

Figure 13K shows the final form of the molecular structure, with all the liberated hydrogen converted to water and all the α-carbons converted to carbonyl groups.

- 9 formed into anthers. We can also see the deradicalized oxygen molecule from the radical ·Ο—O—H. This illustrates the continuous (cascade-like) absorption function of the aliphatic chain, in which the larger the chain, the greater the number of potential absorption sites. It is obvious that this increases the potential time of absorption, for example, increasing the shelf life of the packaging.

The compatibility of the absorbent polymer and the polyester is generally characterized by the essential matching of the solubility parameters. For example, the Van Krevelen solubility parameters (as defined hereinafter) of the absorbent polymers and the polyesters are preferably within 3 units and more preferably within 1 unit. The matching of solubility improves the mixing or blending and adhesion of the polymers.

The compatibility of the absorbent polymer and the polyester can be further characterized by the degree of crystallinity. The degree of crystallinity of the absorbent polymer is less than or equal to that of the polyester. This provides the process compatibility to allow bidirectional orientation of the PET, whether in a blend, copolymer or a separated layer, without loss of transparency.

The aromatic ester scavenging polymer may be a homopolymer, a random copolymer, an alternating copolymer, or a block copolymer. The scavenging polymer should contain α-hydrogen carbonyl groups to provide oxygen scavenging function and aromatic and ester groups to provide compatibility with the polyester. The polymer may also contain other functional groups as long as compatibility with the polyester is maintained.

For example, a preferred absorbent homopolymer comprises repeating units of the general formula (VI') described below and designated REVPET. The REVPET repeating unit contains the same amount of aromatic groups (one main chain ring) and the same number of ester groups (two- 10 • f · · · · ·♦· ··· ·* stem) as PET, as well as a 2-carbon (ethyl) group in the main chain. This ensures an exact match of the solubility parameter.

An alternative homopolymer (VIF) contains a repeating unit of the general formula; this polymer is referred to as modified REVPET. Modified REVPET has a very well-matched solubility parameter. There is an additional carbon atom in the aliphatic chain that lowers the Tg. Depending on the application, it may be necessary to form a copolymer (e.g., introduce additional groups that modify the Tg or the degree of crystallinity). Various other absorbent polymers are described in more detail below.

A preferred transparent oxygen scavenging product is a multilayer package, such as a blow molded container, comprising one or more bidirectionally oriented PET polymers and one or more absorbent polymer layers, such as REVPET. The REVPET layer(s) may range in thickness from relatively thin (e.g., about 2% by weight of the container) to relatively thick (e.g., 40% by weight of the container).

In one embodiment, an aromatic ester-type absorbent condensation polymer can be prepared from an aliphatic dicarboxylic acid of the general formula (2) where n = 2 or more, preferably 2-10, or an acid derivative (e.g., dimethyl ester, acid chloride, acid anhydride, diacyl chloride) to provide the α-hydrogen carbonyl group. The aliphatic dicarboxylic acid (or derivative) is reacted with one or more aromatic glycols or diacetates of the general formula (3) or (4), where n and m are the same or different and are 0-6, and R' and R" are the same or different aromatic main chain or side chain groups as described above (see Figures II and 3 and the accompanying description). These glycols and diacetates contain aromatic rings and adjacent oxygen atoms (the main chain oxygen in the ester group of the aromatic ester polymer). The molar ratio of aromatic groups:ester groups:oc-hydrogen carbonyl groups is preferably 1:2:2 for polycondensation homopolymers. Copolymers often have a different molar ratio due to optimization of the Tg of the absorbing polymer.

It is believed that cobalt improves the oxygen scavenging capacity of the aromatic ester type scavenging polymer of the present invention. Preferably, 50-500 pg of cobalt is added per 1 g of scavenging polymer. Cobalt is preferably added in the form of cobalt neodecanoate or cobalt acetate. Alternative such improvers include magnesium and manganese acetate.

These and other features of the present invention are described in greater detail in the following detailed description and drawings.

Figures 1A-1K illustrate various polymer preparation methods, including a prior art 2-step process for preparing PET (Figure 1A), and Figures 1B-1K illustrate various methods for preparing oxygen scavenging polymers useful in our invention.

Figure 2 is a vertical cross-section of a multilayer ‘preform’ used in the production of a beverage container (bottle) according to one embodiment of the invention.

Figure 3 is a side view of a multilayer pressure-resistant bottle formed from the preform of Figure 2.

Figure 4 is a horizontal cross-section of the multilayer side wall of the container taken along line 4-4 of Figure 3.

Figure 5 shows a vertical cross-section of a blow molding apparatus used to produce the container of Figure 3.

Figure 6 is a vertical cross-section taken along line 6-6 of Figure 3, showing one leg of the container.

Figure 7A shows an enlarged partial cross-section of a crystalline neck end and cap, according to one embodiment.

Figure 7B shows an amorphous neck end and cap - another

- 12 .:.. ..·.:.. J.

according to the embodiment - shows an enlarged partial cross-section.

Figures 8A and 8B show side views of a multilayer preform and a finished container according to another embodiment of the invention.

Figure 9 is a schematic cross-section of a preform for making a can according to an alternative solution.

Figure 10 is a schematic cross-section of an intermediate product formed from the preform of Figure 9, comprising a lower portion with a chamber oriented upwardly in two directions through the end and an upper portion which has been removed and discarded.

Figure 11 is a schematic cross-section of a preform according to another embodiment, having an inserted neck portion and multilayer body and base forming portions.

Figure 12 is a graph showing the internal temperature and pressure changes during a typical pasteurization cycle for a prior art glass container (bottle) of approximately 340 g (12 oz) filled with 2.5 times its volume of carbonated fruit juice.

The series of Figures 13A-13K show the sequence of steps in the consumption of oxygen by the aliphatic chain of the alpha-hydrogencarbonyl group.

The present invention relates to aromatic ester-type scavenger polymers having α-hydrogen carbonyl oxygen scavenger groups which can be blended or copolymerized (including transesterification) with an aromatic polyester polymer or used in a layered structure with the polyester polymer to form a transparent article for storing oxygen-sensitive products. In the main embodiment described herein, the scavenger polymer is used to injection mold a substantially transparent preform and blow mold the preform to form substantially transparent bottles for beer, juice, ketchup and other oxygen-sensitive products. The specific materials, wall thickness, layer structure and container design will depend on the specific

- 13 .:1. .t.·*' depends on the product and the filling conditions, sterilization and use, however, the common goal is to provide an active barrier layer protection in a cost-effective manner for use with commercially available aromatic polyester resins (e.g., PET and PEN) such that the finished container or bottle is substantially transparent, lightweight and has the structural integrity required for a commercially acceptable polyester container.

In embodiments of the invention, the aromatic ester oxygen scavenging polymer should have chemical and physical properties that result in substantially transparent preforms and packaging structures formed partially or completely therefrom. For example, aside from its oxygen scavenging ability during use, the scavenging polymer should be substantially chemically inert under the conditions used in forming the preforms and packaging structures, and under the conditions of storage of such preforms and packaging structures in an unfilled state. For example, it may be desirable for the polymer end groups to have reduced chemical reactivity. Preferably, the oxygen scavenging polymer should not adversely affect the transparency, melting temperature, viscosity, or other processing parameters of the polymer composition. In addition, in specific embodiments, the oxygen scavenging polymer should also be chemically inert to the food and/or beverage to be stored within the packaging.

As an introduction, we will review some of the well-known principles of PET synthesis. A dicarboxylic acid can be condensed with a glycol, or a hydroxy acid can be self-condensed to form a linear polyester (e.g., PET). Figure 1A (K. Wissermal and H.J. Arpe, Industrial Organic Chemistry, Section 14.4, Application of Terephthalic Acid and Dimethyl Terephthalate, Verlag Chemical Press (1978), pp. 349-351) shows a two-step process for PET synthesis. In the first step, dimethyl terephthalate (DMT) is transesterified with ethylene glycol with the elimination of CH3OH; in another possible first step (not shown), terephthalic acid (TPA) is esterified with ethylene glycol with the elimination of water. This first step is carried out at a temperature of 100-150 °C and a pressure of 10-70 bar, for example in the presence of a copper, cobalt or zinc acetate catalyst. The intermediate product obtained is bis(2-hydroxyethyl) terephthalate. In a second step, the intermediate is subjected to catalytic polycondensation to produce PET; this typically takes place at a temperature of 10-20 °C above the melting point of PET (246 °C) under vacuum and often with a catalyst such as SbjCl. During the polycondensation step, the ethylene glycol is removed. The resulting PET melt is then cooled and granulated. In Figure 1A and the following figures, the atoms/groups to be removed are shown circled and indicated by arrows to facilitate identification of the reaction sites.

PET is a thermoplastic polyester which can be used in stretch-oriented form as both a packaging film (foil) and as a molded beverage bottle. It is commercially available as a homopolymer or, more preferably, as a copolymer with small amounts of other monomers to improve processability or properties (e.g., heat resistance). For example, there are well-known PET copolymers which contain varying amounts, generally at least 10 mol%, of other monomers compatible with PET and which do not substantially reduce the structural properties and processability parameters of PET. These copolymers can also be used in the present invention. Accordingly, as used herein, the term "PET" includes both homopolymers and copolymers.

Figure 1B: REVPET

Figure 1B shows a process for preparing an oxygen scavenging polymer, which we will refer to here as “REVPET.” The repeating units of REVPET

- 15 .:.. J.·(see Figure IB) contain the same number of carbon atoms, oxygen atoms and hydrogen atoms and have the same molecular weight as the repeating units of PET (see Figure 1A). Therefore, REVPET is highly compatible with PET, allowing it to be blended and/or copolymerized with PET, or used with PET in a layered structure in which the PET can be oriented in two directions and remains substantially transparent. The term "transparent" is used herein in the sense of substantially transparent, as a storage container is considered to be a transparent storage container even though its transparency may be reduced by crystallinity or other similar factors. The definition of transparency is given in ASTM D1003, which will be discussed later.

The structural difference between REVPET and PET (shown in Figures 1A-1B) is that in REVPET the main chain oxygen in each ester group (COO) is adjacent to the aromatic ring, and thus the _CH2 group (adjacent to the C of the ester group) provides an alpha-hydrogen carbonyl functionality for oxygen absorption.

REVPET has two α-hydrogen carbonyl groups per unit, which provide relatively high oxygen absorption. The two ester groups, one aromatic ring and two methyl groups in the main chain provide good similarity in solubility parameters to PET, thus enabling their combined use in blends, copolymers and layered structures with good adhesion and transparency between layers.

The table in Appendix C lists the various properties of REVPET (and other polymers shown in Figures 1B-1K) compared to PET.

The properties are as follows:

Tg

Tm glass transition temperature melting temperature

SOL solubility parameter (Van Krevelen, see later) ADEN amorphous polymer density CDEN density of crystalline polymer PERM nitrogen permeability of amorphous polymer AROMA aromatic ring molar mass percentage based on the total mass of the absorbent polymer (per repeating unit); except for bisphenol-A, where the aromatic ring molar mass percentage includes the CH3-C-CH3 between the 2 rings CARB the mole percent of C and O in the carbonyl group based on the total mass of the absorbent polymer (per repeating unit); except for nylons, where the number is multiplied by 1.5 to include the reactive carbonyl group next to the NH group. ALPHA the mole percent of (CH ₂ ) _n in the aliphatic group adjacent to the carbonyl group; except for nylons, where the number is multiplied by 1.5 to include the reactive carbonyl group adjacent to the ΝΉ group.

The first column, Tg, is a very important parameter discussed above. The Tg of the absorbent polymer should be at least 10°C lower than the orientation temperature of the polyester polymer with which it is processed (in the transparent product). REVPET has a Tg of 43°C, much lower than the typical orientation (stretching) temperature of PET (e.g. 90°C or higher). The second column, Tm, shows that REVPET has a melting temperature of 214°C. The third column, the solubility parameter, shows that REVPET has exactly the same solubility parameter (20.53) as PET. The fourth and fifth columns, the densities of the amorphous and crystalline polymers are the same for REVPET and PET. The solubility for nitrogen (PERM) is also the same.

The last three columns, AROM, CARB and ALPHA, express the mole percent of the 3-functional groups in the absorber polymer that have a significant impact on the properties. AROM, the weight percent of the aromatic ring, has the greatest effect on Tg, i.e., as the aromatic character increases, the Tg generally increases. For example, REVPET has a rather low Tg compared to the absorber polymers discussed later. The higher Tg provides a higher service temperature and reduces the possibility of the absorber polymer crystallizing (or clouding) during the orientation process. CARB, the weight percent of the carbonyl group (CO), has a large effect on the degree of absorber property, i.e., more α-hydrogen carbonyl groups mean greater absorption capacity. ALPHA, the weight percent of the aliphatic chain, has a large effect on the long-term absorption capacity, i.e. as the chain length increases, the number of potential reactive sites for absorption increases and thus the storage time that the packaging can provide increases. Example calculations for these parameters are provided in Appendix C.

The preferred value limits are:

AROMA: 30-70

CARB: 5-30

ALPHA: 5-30

The reaction shown in Figure 1B can be carried out by various well-known methods:

PREPARATION OF POLY(HYDROQUINONE SUCCINATE), REVPET BY INTERFACIAL POLYCONDENSATION [see W.M. Eareckson III, J. Polymer Science, 40, 399 (1959)]:

0.05 mol of hydroquinone and 0.1 mol of sodium hydroxide dissolved in 300 ml of water are added to a mixer. 3 g of sodium lauryl sulfate in 30 ml of water are also added. The speed is adjusted so that at low speed 0.05 mol

- A second solution of succinyl chloride 18 in 150 ml of hexane is rapidly added.

The mixture is stirred at high speed for 10 minutes and then poured into acetone. The polymer is filtered off, washed with water and dried. The polymer is obtained in 80% yield.

Hydroquinone can be replaced with bisphenol-A to produce a polymer with a higher Tg (see Figure 1J).

Succinoyl chloride can be replaced with other acid chlorides to increase the absorption capacity or adjust the Tg. Replacing succinic acid with glutaric acid results in the modified REVPET described later. If an aliphatic acid is used in the above reaction, it may be advantageous to replace sodium hydroxide and water with pyridine.

ANOTHER PROCESS FOR THE PREPARATION OF HYDROQUINONE SUCCINATE (REVPET) (see GB Patent Specification No. 636 429 Eric R. Wallsgrove and Frank Reeder, April 26, 1950):

parts of hydroquinone diacetate are mixed with 9.5 parts of succinic acid and 0.1 part of p-Me-CóHiSOsH. The reaction mixture is heated at 180 °C for 45 minutes, then at 200-220 °C for 1 hour, then at 280 °C for 3 hours at atmospheric pressure, and finally at 280 °C for 3 hours at 133 Pa (1 mm Hg) while nitrogen gas is bubbled through the molten mixture.

Alternatively, isomers of the monomers described above can be used to adjust the Tg by a small amount and the crystallinity by a larger amount. For example, the hydroquinone substitute can be resorcinol of formula (5), which can be used in various molar concentrations in the above processes for preparing REVPET; for example, the introduction of 20 mol% resorcinol increases the Tg by 2 °C and reduces the crystallinity by 50%.

Figure IC: Modified REVPET

Figure 1C shows the preparation process of the second oxygen scavenging polymer described herein as modified REVPET. The only difference between the modified REVPET and REVPET is the addition of an additional _CH2 group in the aliphatic chain. In the table in Appendix C, we can see that the solubility parameter (SOL) of the modified REVPET is 20.18, compared to 20.53 for PET. It may be necessary to introduce additional functional groups, which increase the Tg. Examples of such modifications of Tg are described below in Figures 1D-1K.

The conditions for the modified REVPET preparation process are similar to the REVPET preparation process described above, in which succinic acid was replaced by glutaric acid.

Figure 1D: 1D polymer

Figure 1D shows a process for preparing another aromatic ester type oxygen scavenging polymer, designated as polymer 1D, according to the present invention. The repeating unit (see Figure 1D) contains two alpha hydrogen carbonyl groups, two ester groups, six aromatic rings (two in the polymer chain and four in the side chain), and a 3-carbon aliphatic group. The six aromatic rings increase the Tg (compared to PET), but the excess carbon atoms (3CH3) in the aliphatic chain reduce the Tg (compared to the 2-carbon chain in PET). Thus, by replacing various functional groups in the polymer, and/or similarly by changing the appropriate ratios of functional groups in the polymer, the Tg can generally be reduced or increased. These functional groups and their regularity can similarly affect the degree of crystallinity. In general, the skilled artisan will then be able to determine the appropriate proportions of the various groups for a given application, based on the process conditions required, to achieve a transparent oxygen scavenging polymer comprising bidirectionally oriented PET and an aromatic ester type polymer either blended or copolymerized with PET, or alternatively in a separate layer structure. Similarly, the starting materials may be varied depending on the prices and commercial availability of the appropriate components.

PROCESS FOR PREPARATION OF 1D-POLYMER FROM DIPHENYLDICARBOXYLIC ACID DIMETHYL ESTER, DISTYROL GLYCOL AND GLUTARIC ACID DIMETHYL ESTER

In a hermetically sealed 3-necked, 1-liter flask equipped with a stirrer, 0.25 mol of the two dimethyl esters, 1.1 mol of glycol, and 0.0464 g of cobalt acetate were stirred. The vessel was pressurized to 69 10 ³ Pa (10 psi) and slowly heated to about 180 °C with stirring until it was slightly boiling. At 69 10 ³ Pa (10 psi), the temperature was slowly increased to 250 °C, maintaining the mixture at just boiling. The reaction mixture was maintained at 250 °C for 2 hours. The pressure was then reduced and a vacuum was applied. 0.033 g of SbOa dissolved in a small amount of glutaric acid dimethyl ester was added to the reaction mixture. The temperature was raised to 280 °C. The reaction mixture was maintained at 133.3 Pa (1 torr) for 4 hours.

Figure 1E: lE-polymer

Figure 1E depicts another aromatic ester type oxygen scavenging polymer for use in the present invention. The repeating unit (see Figure 1E) contains two alpha-hydrogen carbonyl groups, two esters, a 4-carbon aliphatic chain, and an aromatic structure (containing two rings) in the backbone. While the 4-carbon aliphatic chain would lower the Tg (compared to the 2-carbon chain in PET), the additional aromatic ring would increase the Tg (compared to the single-ring system in PET). The calculated Tg of the lE polymer is 71°C (see Appendix C), which is just above the Tg of PET (70°C) and in the preferred range. The lE polymer is available from Dow Chemical, Midland, Michigan, USA.

The ratios of the components can be adjusted for specific applications. In general, to increase the oxygen absorption rate, the number of alpha-hydrogen-21-carbonyl groups should be increased by substituting more adipic acid and the amount of bisphenol-A diglycidyl ether should be reduced. A modified version of the ÍE polymer made with succinic acid has a Tg of 70 °C.

Figure 1F: lF-polymer

Figure 1F shows another alternative aromatic ester type oxygen scavenging polymer, designated as IF polymer. The repeating unit contains two α-hydrogen carbonyl groups, two esters, a 4-carbon aliphatic chain, and an aromatic side chain. The relative proportions of the “active ingredients” can also be modified to suit the specific application.

Another polymer made with succinic acid instead of adipic acid has a higher Tg (see table in Appendix C). Further increases in Tg are possible by using distyrol oxide (instead of styrene oxide) with adipic acid, or distyrol glycol (instead of styrene oxide) with succinic acid.

Figure 1G: REVPEN

Figure 1G shows a process for the preparation of another absorbent polymer, designated REVPET. It is similar to REVPET (Figure 1B), except that it is based on naphthalene instead of benzene. REVPEN is prepared by the condensation of 1,2- or 2,6-naphthalene diacetate and succinic acid dimethyl ester. The reaction conditions are similar to those for the preparation of REVPET, except that a higher temperature (about 300 °C) is used in the final step.

A modified version of REVPEN containing an additional CH ₂ group on each side of the aromatic ring is presented with the general formula (V”).

Figure 1H: IH-polymer

Figure 1H shows random polymers of groups A, B and C, where A is naphthalene dicarboxylate (NDC), B is adipic acid and C is ethylene glycol (where the atoms/molecules to be cleaved are indicated by arrows in a square). The resulting IH polymer is essentially a random poly of PEN and adipic acid:

- 22 moles. For every two naphthalene components, there is one aliphatic component (moles). It is a solid, highly crystalline polymer that is stable at high temperatures. This allows for easy drying and curing by increasing the molecular weight. Polycondensation polyesters with a highly crystalline structure and high melting point can be hardened by increasing the molecular weight.

The transparent, multi-layer blow-molded bottles are made from a preform containing previously unused PET layers and IH polymer layers. There is good adhesion between the layers, which prevents delamination.

More generally, the aliphatic acid component (here adipic acid) may contain a (CH ₂ ) _n group, where n is between 2 and 10.

PROCESS FOR PREPARATION OF DIMETHYL-2,6-NAPHATLINE DICARBOXYLATE/ADIPIC ACID AND ETHYLENE GLYCOL COPOLYMER - 1H-POLYMER

In a 3-liter two-necked reaction vessel equipped with a stirrer, 2.4 mol (580 g) of NDC, 1.2 mol (175 g) of adipic acid, 8 mol (496 g) of ethylene glycol and 0.4725 g of SbO ₃ were mixed. Nitrogen gas was bubbled through the system at a pressure of 55 10 ³ Pa (8 psi), heated to 175 °C and held at this temperature for 10 minutes. The reaction mixture was then heated to 210 °C and held there for 5 minutes. The temperature was again increased to 240 °C and held for 1 hour after the sample had cleared. The temperature was increased to 260 °C and held for 1 hour. The temperature was increased to 275 °C and held for 3 hours. The pressure is switched to vacuum and the reaction mixture is held at 275 °C under a uniform vacuum for an additional 4 hours. The final vacuum should be less than 133 Pa (1 torr).

Figure II: 11-polymer

Figure II, where a substituted hydroxy acid monomer is shown with acetate at one end and ethyl, methyl ester at the other end; this mono···:

- 23 mer reacts with itself to form a further oxygen scavenging polymer containing the repeating unit shown. The 11-polymer contains an aromatic ring, an ester group, an alpha-hydrogencarbonyl group and a 2-carbon aliphatic chain.

PROCESS FOR POLYMERIZATION OF 4-ACETYLOXYBENZENE-PROPIONIC ACID TO PREPARE 11-POLYMER

In a sealed, two-necked, 1-liter vessel equipped with a stirrer, 136 g (1 mol) of acid, 0.13 g of SbCl2 and 0.19 g of cobalt acetate are weighed. The reaction mixture is heated to 150 °C with gentle stirring at a pressure of 69 · 10 ³ Pa (10 psi) at a rate of 0.25 Epere while purging with nitrogen gas. The temperature is increased to a gentle boil, then the purge is reduced while maintaining the pressure of 69 · 10 ³ Pa (10 psi). The boiling and the pressure of 69 · 10 ³ Pa (10 psi) are maintained, the temperature is continued to increase to 180 °C. The pressure and temperature are maintained for 40 minutes. We switch to vacuum and raise the temperature to 210-220 °C over 90 minutes.

Figure 1J: IJ-polymer

Figure 1J shows the condensation of bisphenol A diacetate and adipic acid to produce an IJ polymer containing two α-hydrogen carbonyl groups, two esters, an aromatic backbone (with two rings), and a 4-carbon aliphatic backbone. In the table in Appendix C, we can see that the IJ polymers have a relatively high Tg of 91 °C. In the table, the modified polymer listed under the IJ polymer, labeled “Bis A Acetate/Suberic Acid”, has a lower Tg of 79 °C, which is in the preferred range of orientation temperatures for use with PET.

The following process can be used to prepare a polymer from bisphenol-A and suberic acid.

POLYMER PREPARATION FROM BISPHENOL-A AND SUBERIC ACID (see for example Preparative Methods Of Polymer Chemistry, 2nd

- 24 Edition, Sorensen, Campbell, page 149):

In the first step, bisphenol-A diacetate was prepared in a 250 ml Erlenmeyer flask by dissolving 11 g of bisphenol-A in 45 ml of water and 9 g (0.22 mol) of sodium hydroxide. The mixture was cooled in an ice bath and a small amount of ice was added to the flask. Then, 22.4 g (0.22 mol) of acetic anhydride was added to the flask and the flask was shaken vigorously in an ice bath for 10 min. The white solid powder was filtered, washed with water and recrystallized from ethanol.

312 g (1 mol) of bisphenol-A, 174 g (1 mol) of suberic acid, 0.60 g of toluenesulfonic acid (monohydrate) were placed in a 2-liter two-necked flask equipped with a stirrer. The flask was purged with nitrogen while stirring for 20 minutes. The temperature was raised to 180 °C with stirring and purging with nitrogen at atmospheric pressure. Acetic acid distilled out as the temperature slowly rose from 180 °C to 250 °C while the pressure was slowly reduced to about 133 Pa (1 torr). The melt was held at 250 °C at 133 Pa for 1 hour.

When using an aliphatic acid, it may be advantageous to replace sodium hydroxide and water in the above reaction with pyridine.

I-Figure: IK-polymer

Figure 1K shows the ring-opening polymerization of a cyclic ester. Caprolactone (cyclic) was mixed with a cyclic carbonate ester to produce an IK polymer. The resulting polymer contains two α-hydrogen carbonyl groups, a two-ring aromatic structure (bisphenol-A) in the main chain, and a five-carbon aliphatic chain. In the table in Appendix C, the Tg of the IK polymer is 85 °C, which is in the preferred range for use with PET. The dissolution parameter of the IK polymer matches that of PET well (20 versus 20.53).

A polymerization process for cyclic carbonate esters and lactones has been described

- 25 George Odian, Principles of Polymerization, 3d edition, John Wylie & Sons, Inc., New York (1991), 569-573. pages.

The oxygen scavenging polymers described above (Figures IB-IK) can be used alone or in combination or copolymerization with an aromatic polyester polymer, preferably a PET or PEN polymer, to provide an oxygen scavenging material. This material is then incorporated into a bottled container as described below to provide the desired level of oxygen scavenging property.

Pasteurizable Beer Bottle

Figures 2-6 illustrate a process for producing a transparent, one-liter pasteurizable beer bottle using the multilayer structure and oxygen-absorbing polymer of the invention.

An injection molded multilayer preform 30 is illustrated in Figure 2. The substantially cylindrical preform defined by a centerline 32 includes an upper neck portion or end 34 integral with a lower body portion 36. The neck portion has an upper closure surface 31 defined by the open upper end of the preform, and a generally cylindrical threaded outer surface 33 and a lower flange 35. Below the flange is the body-forming portion 36 which includes an upper cylindrical portion 41, a flared shoulder portion 37 which increases in wall thickness from top to bottom in a radially inward direction, a cylinder-forming portion 38 of substantially uniform wall thickness, and a thickened base portion 39 which is thicker than the cylinder-forming portion 38. The closed bottom 40 of the preform is substantially hemispherical and may be thinner than the base forming section 39.

The preform 30 is a three-material, five-layer structure (3M, 5L) and is substantially amorphous and transparent. The multiple preform layers, in turn, comprise a clear PET outer layer 42, an EVOH outer intermediate layer 43, a central core layer 44 of oxygen scavenging material, and a clear PET inner layer 46. The

- 26 Pure PET is a commercially available, bottle-grade PET homopolymer or copolymer with an intrinsic viscosity of approximately 0.90 dl/g. EVOH with a 32 mol% ethylene content is available from Evalca, Omaha, Nebraska, USA or Kuraray Co. Ltd., Osaka, Japan. The core layer is REVPET as described above (Figure 1B) which has an intrinsic viscosity of 0.70 dl/g, a Tg of 43°C and a melting point of 214°C. The REVPET polymer contains 150 pg of cobalt in the form of cobalt neodecanoate added per 1 g of REVPET polymer.

The preform 30 is used to make a 1.0 liter pasteurizable, pressure-resistant beer bottle as shown in Figure 3. The preform 30 is about 150 mm high and has an outer diameter of 23.8 mm at the cylinder-forming section 38. The total wall thickness of the cylinder-forming section 38 is about 4.1 mm; the inner and outer intermediate layers are each about 0.1 mm thick; and the core layer is about 1.7 mm thick. The cylinder wall thickness of the approximately 0.3-1.5 liter pasteurizable carbonated soft drink bottles is about 0.25-0.38 mm and is filled with an aqueous solution filled with about 2.0-4.0 volumes of _CO2 , the cylinder-forming section 38 of the preform being subjected to a flat average stretch ratio of preferably 13.0-14.5. The planar stretch ratio is the ratio of the average wall thickness of the cylinder-forming section of the preform 38 to the average wall thickness of the cylinder section 86 of the bottle (Figure 3); the average is taken over the entire length of the respective preform and bottle sections. The average annular stretch of the sheet (cylinder) is preferably 4.0-4.5 and the axial stretch is about 3.0-3.2. This results in a bottle cylinder 86 with the desired bidirectional stretch and transparency. The specific cylinder thickness and stretch ratio are selected depending on the dimensions of the bottle, the internal pressure and the processing characteristics (determined, for example, by the intrinsic viscosity of the main materials used).

The preform shown in Figure 2 can be injection molded using the Continental PÉT Te

- 27 chnologies, Inc. of Begford, New Hampshire, by the sequential dosing process described in US 4,550,043; US 4,609,516; US 4,710,118; US 4,781,954; US 4,990,301; US 5,049,345; US 5,098,274 and US 5,582,788. In this process, predetermined amounts of various materials are introduced into the barrier of the preform mold as follows. First, the pure PET is extruded (injection molded), which partially solidifies as it flows onto the cold exterior of the mold and the walls of the mold core, forming the inner and outer interlayers; second, the EVOH is injected, which forms the inner and outer interlayers; and the third time the oxygen absorber is extruded, which pushes the EVOH onto the sidewall (forming a thin barrier layer) and forms the middle core layer of oxygen absorber. The final injection of pure PET can be used to clean the die and finish the bottom of the preform with pure PET.

After the injection mold is filled, the pressure is increased to fill the mold due to the shrinkage of the preform. After filling, the mold pressure is partially reduced and held until the preform cools. In a standard process, each polymer melt is injected into the mold at a rate of 10-12 g/sec, a filling pressure of approximately 50 10 ⁶ N-m' ² (7500 psi) is applied for approximately 4 sec, and the pressure is reduced to 30 10 ⁶ N-m' ² (4500 psi) over the next 15 sec, after which the pressure is released and the preform is ejected from the mold. Increasing the pressure above these levels can cause greater internal bonding, which may include cross-linking, hydrogen bonding, small-scale intralayer crystallization, and interlayer penetration; This can be useful in specific applications to increase the resistance to delamination in both the preform and the bottle. Furthermore, the increased pressure allows the preform to be cold-formed without loss of haze, i.e. transparency.

on the mold wall until solidification with the shortest possible cycle time. Moreover, faster injection speeds can cause higher melt temperatures in the injection cavity, which results in increased polymer mobility. This improves migration and mixing during the elevated pressure phase of the injection cycle and thus increases resistance to delamination. Alternatively, by increasing the preform temperature and/or reducing the temperature gradient across the preform wall, delamination can be further reduced by minimizing shearing of the interlayer bonds during the preform expansion period.

Figure 5 shows a stretch blow molding apparatus 70 for forming a bottle 80 from a preform 30. More specifically, the body-forming portion 36 of the substantially amorphous and transparent preform is reheated above the glass transition temperature of the inner/outer PET and oxygen scavenger layers, and the heated preform is then inserted into a blow mold 71. A stretch rod 72 axially elongates (stretches) the preform within the blow mold, ensuring full axial elongation and centering of the preform. The thickened base forming section 39 of the preform is more resistant to axial deformation relative to the cylinder and shoulder portion of the bottle. Blowing gas (indicated by arrow 73) is introduced radially inflating the preform to fill the inner mold surface 74 of the blow mold. The formed container or bottle remains substantially transparent but has undergone a stretch-induced bidirectional orientation, providing the increased strength necessary to withstand carbonation and the higher temperatures and pressures of pasteurization.

Figure 3 shows a 1 liter pasteurizable multilayer soft drink bottle 80 made from the preform of Figure 2. The preform body forming portion 36 has been expanded to form a transparent, bidirectionally oriented bottle body 81. The upper threaded end 34 has not been expanded, but it has sufficient thickness or

- 2 9 - <·<;·’> ·: “?

· · · * · material structure provides the necessary strength. The bottle has an open upper end 82, and a screw-threaded cap is provided on this (Figures 7A-7B). The so-called bottle body 81 includes:

(a) an upper flared shoulder portion 83 with an outwardly extending profile and generally increasing in diameter from the flange 35 below the neck to the cylindrical section 86, this is advantageous for forming a rounded (hemispherical) shoulder portion 83 because this shape maximizes bidirectional orientation and minimizes applied stress levels. Greater orientation and lower stress reduce the increase in container volume that occurs due to cold flow at higher temperatures (during pasteurization) and thus minimizes any decrease in fill level; it is also advantageous to provide a small transition radius 84 between the neck 34 and the shoulder 83 to minimize the unoriented area at the top of the shoulder (the unoriented area may be prone to cold flow); (b) the substantially cylindrical section 86 is preferably long and elongated, i.e., the height to diameter ratio is 2.0-3.0, in order to minimize wall stress (and minimize cold flow); relatively small curved transition regions 87 and 88 are provided at the upper and lower ends of the cylindrical section 86; the larger transition region is more likely to expand (straighten) during pasteurization and cause an increase in volume (reduction in fill level); for the same reason, the cylindrical section 86 is preferably made ribless (which may flow);

(c) the base portion 90 has a substantially hemispherical bottom wall 92 and five legs 91 extending downwardly from the bottom wall to form five legs 91 on which the container rests; the legs 91 are arranged symmetrically around the circumference of the container; it is advantageous to provide a base of great depth, i.e., for the hemispherical

provide a base as close as possible to increase strength and resistance to cold flow; it is also advantageous to provide a sloping base portion that can move outward during cold flow and still remain within the diameter of the container.

The section of the preform 38 forming the cylinder can be stretched at a plane stretch ratio of 13.0-14.5; the resulting straight section 86 has an average stretch-induced crystallinity of 20-30%, preferably 25-29%. The shoulder portion 83 undergoes an average plane stretch ratio of 10.0-12.0; the resulting pure PET layers of 20-25% have an average crystallinity of 20-25%. The hemispherical bottom wall 92 in the base undergoes an average plane stretch ratio of 5.0-7.0, and the pure PET layers have an average crystallinity of 5-15%, the legs and soles undergo an average plane stretch ratio of 13.0-14.0, and the virgin PET layers have an average crystallinity of 20-26%. The average crystallinity level of the oxygen-absorbing core layer is approximately 2% lower than that of the pure PET layers at the same locations in the container, i.e. 18-28% in the cylindrical part, 18-23% in the shoulder part, 3-12% in the hemispherical bottom wall and 18-24% in the legs and soles.

Figure 4 shows a cross-section of the cylindrical portion 86, which includes an inner layer of pure PET 95, a core layer of oxygen scavenger 96, an outer layer of pure PET 97, and outer and inner interlayers of EVOH 98, 99. In this embodiment, the total weight percentage distribution of the various layers in the cylindrical portion is about 30% inner layer 95, about 40% core layer 96, and about 30% outer layer 97 (the EVOH 98, 99 layers together are less than 2% by weight). The inner interlayer of EVOH 98 becomes permeable to oxygen when water vapor from a product permeates the inner layer of PET 95; this allows oxygen in the container to permeate through the layers 95 and 98 to reach the core layer 96, where it is absorbed. In contrast, the outer layer 99 remains relatively dry and resists external oxygen from entering the container. In an alternative embodiment, it may be desirable to replace the REVPET in the core layer with a blend of PET and REVPET, where 5-20% by weight of the core layer is REVPET; this provides a higher Tg.

The advantageous features of the base of the container with a base are more clearly illustrated in Figure 6. The known five-legged PET disposable carbonated soft drink container (non-pasteurizable) used as a basis for comparison has a relatively small base profile (Θ is about 45°). In contrast, the present base preferably has a relatively high base profile of 60° or better. Figure 6 shows a full hemisphere A with Θ = 90° and the dashed lines show a truncated hemisphere B with Θ = 60°. Θ is the angle between the radius R defining the hemispherical bottom wall 92 and the vertical centerline (CL) of the container. The relative heights of the base are denoted by _HA for the full hemisphere and Ηβ for the truncated hemisphere. Preferably, the height of the foundation is between Ha and Hb, and more preferably, where Θ is greater than 65°.

It is preferred to provide a slanted base portion. The base portion is between points G and K on the leg portion 91 (Θ = 90°), or 9Γ (Θ = 60°). The base portion preferably extends a distance L _F from the vertical (CL) centerline to a point G aligned vertically with the center of the radius R _g . The radius R g forms the outer edge of the base portion. The base portion forms a constant angle with the horizontal surface 102 on which the base rests. Preferably, L _F is 0.32-0.38R and a is 5-10°, allowing the base and leg to move outward during cold flow while still remaining within the diameter of the container.

Figure 7A depicts an enlarged cross-section of a blurred neck end according to one embodiment. More specifically, the unoriented neck end 110 is thermally crystallized (blurred), for example by exposure to high temperatures; this increases strength and improves its resistance to pasteurization.

- 32 gasabber temperature and pressure. The heat-treated area may extend just to the bottom of the flange 111. The cap 116 has a ring seal 117 of a flexible material (e.g. plastisol or other thermoplastic elastomer) which seals the sealing surface of the neck end 112. If deformation of the neck end occurs during pasteurization, the washer 117 deforms to provide an airtight seal and prevent leakage.

In another embodiment, shown in Figure 7B, a substantially amorphous and non-oriented, i.e. non-crystallized, neck end 120 is formed. In this embodiment, the amorphous neck end is provided with a flat foil pad 124 that is positioned within the inner surface of the cap 126 and is secured, for example, by heat or adhesive, to the upper insulating surface 122 of the neck end. If there is any deformation in the neck end, the pad 124 provides an airtight seal to prevent leakage.

Other implementations

Figure 8 shows a 0.5 liter, non-pasteurizable beer bottle. In this example, the bottler thoroughly filters the beer without heat treatment. The preform 200 for making the bottle is shown in Figure 8A, which includes a threaded end 201, a flared shoulder 202, a cylindrical body 203, and a closed bottom 204. The preform 200 and the resulting blown bottle 210 (Figure 8B) have a five-layer construction (not shown) that includes inner and outer, pure PET layers (62% by weight), a used (post-consumer) PET core layer (35% by weight), and 2 thin, intermediate REVPET homopolymer layers as oxygen scavenging absorber polymers (3% by weight). REVPET has an intrinsic viscosity of 0.70 dl/g, a Tg of 43 °C and a melting point of 214 °C. The pure PET product Shell 8006, called 0.80 IV, contains 4 mol% isotactic acid copolymer (marketed by Shell Oil Company, Houston, Texas, USA). In contrast to the previous embodiment, this beer bottle has a mushroom-shaped base 212,

- 33 : . • · which includes a standing ring 214 surrounding a central upstanding dome 216. This bottle allows a storage time of approximately 16 weeks for the beer.

Another embodiment includes a relatively wide-mouthed container, such as a can, containing the oxygen scavenger material of the present invention. The can can be formed from a preform according to the process described in Beck et al. U.S. Patent No. 4,496,064, issued January 29, 1985, which is incorporated herein by reference. Preform 142 (from the Beck patent) is shown in Figure 9 and includes a support flange 144, a thin upper body portion 145 that expands into a thick, generally cylindrical main body portion 146, and a generally hemispherical bottom portion 148. The Beck process allows for a high degree of bidirectional orientation in all parts of the resulting container such that the container has an economically thin wall and the required strength characteristics. In this case, the preform is called upon to form an intermediate product 150 comprising a lower portion 152 of the desired container and an upper portion 154. The lower portion comprises a cylindrical body 132, a concave bottom 134, a conically formed shoulder 136, a mouth 138, and an annular flange 130. The upper portion is separated from the flange 130 at point 164 (by cutting or laser cutting) and can be discarded or ground and the material reused. It is generally not necessary to thermally crystallize or otherwise strengthen the upper end of the container because the bidirectional orientation provides the necessary strength. One method is described in Piccoli et al., issued September 3, 1985, and incorporated herein by reference. In US Patent No. 4,539,463, the term preform is used to edge the preform, removing the upper non-oriented portion.

A further method for producing a multilayer preformed container with a crystallized neck end is disclosed in US 08/534126.

- 34 t . • · in the specification entitled “Preform And Container With Crystallized Neck Finish And Method Of Making The Same,” filed by Collette et al. on September 26, 1995 (File No. 7191), which is incorporated herein by reference. As described therein, a product mover (rotating or oscillating) has two jaws, each with a series of preform cores, and simultaneously inserts the two series of cores into two different series of preform mold cavities. In the first series of cavities (first molding stage), a high Tg amorphous or crystalline neck portion is formed on one series of cores, while in the second series of cavities (second molding stage), many amorphous body-forming portions are formed on the other series of cores. The cores are sequentially inserted in each of the first and second molding stages. An efficient process is provided by simultaneous molding in the two series of cavities. By separately molding the neck and body portions in different cavities, different temperatures and/or pressures can be used to set different molding conditions and thus different characteristics in the two preform portions. For example, in one embodiment of FIG. 11, a polyester preform (for making a hot-fill container) has a neck portion of crystallized CPET 180; CPET is a terephthalic acid-based polyester containing a nucleating agent that causes the polymer to crystallize rapidly during injection molding. CPET is available from Eastman Chemical Company, Kingsport, Tennessee, USA. The body portion 181 is a bi-material, three-layer structure (2M, 3L) and includes inner and outer layers of pure poly(ethylene terephthalate) (PET) and a core layer of the oxygen scavenging polymer of the invention. The base-forming portion 182 is similar to the body-forming portion, but may include a layer of pure PET 183 at least in the bottom portion and possibly extending to the outer half of the preform. Alternatively, the core layer 183 in the base may be a higher Tg polymer to improve the thermal stability of the resulting container base; this is particularly useful for mushroom-type containers.

- 35 · ( . ·.

• · ·» in the case of thin bases. The higher Tg polymer can be injected using a third extruder. A number of alternative high glass transition temperature (Tg) polymers can be used instead of CPET, such as acrylate polymers; poly(ethylene naphthalate) (PEN) homopolymers, copolymers or blends; polycarbonates; polyarylates; etc. A number of alternative polymers and layer structures can be incorporated into the body forming portion, including PEN, ethylene vinyl alcohol (EVOH) or MXD-6 nylon barrier layer, etc. The container is suitable for a variety of applications, including refillable, pasteurizable, and hot-fill containers.

As a further alternative, instead of or in addition to providing the oxygen scavenger as part of the wall of a packaging material, the oxygen scavenger can be provided as an insert that is added to the container. For example, the insert can consist of an oxygen scavenger coated with a polymer that is impermeable to oxygen when dry and permeable when wet. Moisture in the product then permeates the coating, allowing oxygen to permeate to the oxygen scavenger core layer.

Identification of alternative materials and properties

The PET polymers used herein include homopolymers, copolymers and blends of PET with other known compatible polymers, including other polyesters such as poly(butylene terephthalate) (PBT), poly(propylene terephthalate) (PPT), poly(ethylene naphthalate) (PEN) and cyclohexane dimethanol substituted PET copolymer (known as PETG, Eastman Chemical Company, Kingsport, Tennessee USA). Preferably at least 90 mol% terephthalic acid and at least 90 mol% aliphatic glycol or glycols, especially ethylene glycol.

Used PET (PC-PET) from PET plastic containers and other recyclables returned by users to the recycling operation

- We manufacture 36 materials that are FDA approved for use in food containers. PC-PET is known to have a range of I.V. (intrinsic viscosity), moisture content, and impurities. For example, typical PC-PET [maximum 3.8 cm (1.5 inch) wafer size] has an average I.V. of approximately 0.66 dl/g, a moisture content of less than 0.25%, and the following impurities:

PVC: <100 ppm aluminum: <50 ppm olefin polymers (HDPE, LDPE, PP): <500 ppm paper and labels: <250 ppm colorful FIVE: <2000 ppm other contamination: <500 ppm

PC-PET can be used alone or in one or more layers to reduce cost or for other benefits.

Another useful aromatic polyester is poly(ethylene naphthalate) (PEN). PEN provides a 3- to 5-fold improvement in oxygen and carbon dioxide barrier properties and improved heat resistance, at a slightly higher cost compared to PET. Poly(ethylene naphthalate) (PEN) is a polyester formed by the reaction of dimethyl-2,6-naphthalene dicarboxylate (NDC) and ethylene glycol. The PEN polymer contains ethylene-2,6-naphthalate repeat units. PEN resin with an intrinsic viscosity of 0.67 dl/g and a molecular weight of about 20,000 is available from Amoco Chemical Company, Chicago, Illinois. PEN has a glass transition temperature, Tg, of about 120 °C, and a melting temperature, Tm, of about 267 °C. PET and PEN can be blended or copolymerized in varying proportions. In the range of about 0-20 wt% PEN and 80-100 wt% PET, the material is crystalline, while at about 20-80 wt% PEN content, the material is essentially amorphous.

Among other useful bidirectionally orientable aromatic polyesters

- 37 include: poly(propylene terephthalate), poly(butylene terephthalate), poly(ethylene isophthalate), poly(cyclohexane dimethanol terephthalate), poh(propylene naphthalate), poly(butylene naphthalate), poly(cyclohexane dimethanol naphthalate).

The multilayer preform/container may also contain one or more oxygen/carbon dioxide/moisture barrier materials such as ethylene vinyl alcohol (EVOH), PEN, polyvinyl alcohol (PVOH), polyvinylidene chloride (PVDC), nylon 6, crystallizable nylon (MXD-6), LCP (liquid crystalline polymer), amorphous nylon, polyacrylonitrile (PAN) and styrene acrylonitrile (SAN). The properties of some of these barrier materials are given in the table in Annex C for comparison purposes.

It may be desirable to use compounds containing cobalt, manganese or magnesium linked to organic ligands as oxygen scavenging catalysts. Examples of catalysts include cobalt neodecanoate, cobalt acetate, magnesium acetate and manganese acetate. It is believed that cobalt may lower the binding energy at the alpha hydrogen carbonyl group, thereby providing greater reactivity with oxygen. The organic ligands are believed to facilitate the penetration of oxygen into the polymer and facilitate the movement of oxidizing gases (Figures 13A-K).

Intrinsic viscosity (I.V.) affects the processability of resins. Poly(ethylene terephthalate) with an intrinsic viscosity of about 0.8 is widely used in the carbonated soft drink (CSD) industry. The viscosity of polyester resins for various applications can range from 0.55 to 1.04 dl/g, more preferably from 0.65 to 0.85 dl/g. The intrinsic viscosity of polyester resins was measured according to ASTM D-2857 using 0.0050 ± 0.0002 g/ml of polymer in a solvent containing o-chlorophenol (melting point 0°C) at 30°C. The intrinsic viscosity (I.V.) is given by:

LV.=(ln(Vsoin/Vsoi))/C

- 38 - · · .· ·;

• · · · · · · · · · · · · · · · · where

Vsoin means the viscosity of the solution in any unit of measurement;

Vsoi. is the viscosity of the solvent in the same unit; and C is the concentration of the polymer in g/100 ml of solution.

The polymers used in this case (aromatic ester oxygen scavenger polymer and bidirectionally oriented polyester polymer) are large polymers with a molecular weight of at least 50,000, for which melt viscosity is an important processing parameter. If the melt viscosity is too high, the polymer cannot be forced through the injection molding nozzle quickly enough to produce conventional preforms. Another important parameter is melt strength; if the melt strength is too low, the integrity of the layer in a multilayer structure containing one or more relatively thin layers cannot be maintained. In general, as the molecular weight of the polymer increases, both melt viscosity and melt strength increase. One skilled in the art will be able to determine the appropriate combination of melt viscosity and melt strength for the oxygen scavenger polymer and the polyester polymer. Melt viscosity is usually given as melt index or flow index, which can be determined according to ASTM test method 1238B. For example, the melt index of Shell 8006 pure PET is 29 g/10 min. It has been found that the melt index of the adjacent absorbent layer should preferably be 50-100 g/10 min.

The curved bottle body must be essentially transparent. One measure of transparency is the percentage of light passing through the wall (Ηψ), which is given by the following formula:

H _T =[Yd-(Y _d +Y _s )]xl00 where Y _d is the scattering of the transmitted light caused by the sample thickness, Ys is the reflection of light caused by the sample thickness. The scattered light passing through is

- 39 turbidity and reflected light were measured using ASTM D1003 test method using any standard color difference measuring device, such as the model D25D3P manufactured by Hunterlab, Inc., Reston, Virginia, USA. The turbidity of the container body (through the wall of the cylindrical portion) should be less than 10%, more preferably less than 5%.

The body-forming portion of the preform should be substantially amorphous and transparent through the wall with a turbidity of no more than 10%, more preferably less than 5%.

The bottle has varying degrees of crystallinity at different locations along the height of the bottle, from the neck end to the base. The degree of crystallinity was determined according to ASTM 1505 test method as follows:

% crystallinity = [(ds-da)/(dc-da)]xl00 where ds is the density of the sample in g/ ^cm3 , da = the density of the amorphous polymer at zero crystallinity, and de = the crystal density calculated from the parameters of a unit cell. The cylindrical part of the container is the most stretched and preferably has an average crystallinity of at least 15%, more preferably 20%. Generally, a useful range of crystallinity in the cylindrical part is 25-29%.

Further enhancement of crystallinity can be achieved by setting the temperature to provide a combination of stretch-induced and thermally induced crystallization. Thermally induced crystallinity is achieved at low temperatures to maintain transparency, for example by keeping the container in contact with a low temperature blow mold. In some applications, the high degree of crystallinity developed on the sidewall surface alone is sufficient.

The oxygen scavenger material of the invention can be produced by masterbatch processing, in which the oxygen scavenger polymer is produced.

- 40 hair, then blended or copolymerized with PET polymer. A masterbatch process for combining the oxygen scavenging polymer and PET is described in US Application Serial No. 08/355703, “Oxygen scavenging compositions for multi-layer preforms and containers,” filed December 14, 1994 (Date No. 7180), published June 20, 1996, WO 96/18685, incorporated herein by reference.

The average molecular weight of the oxygen scavenging polymer can be selected for various purposes. One such purpose may be to improve the miscibility with the PET polymer, and for this purpose the average molecular weight of the oxygen scavenging polymer is preferably 70,000-100,000, and more preferably 78,000-94,000.

The compatibility of the oxygen scavenger polymer with PET can be determined by combining samples of the polymers (blending, i.e. mixing or copolymerizing). Alternatively, it can be determined using various known compatibility indicators. For example, it has been found that the solubility parameter of REVPET, determined according to the known Van Kreleven method, is essentially the same as that of unmodified PET. There is a commercially available software program known as Polymer-CAD, version 1.6 (Novel Advanced Systems For Engineering And Research, P. O. Box 130304, Ann Arbor, Michigan 48113-0304, USA), which allows the calculation of various basic properties of the polymer using the Additive Group Contribution method. For example, using the following structure of REVPET:

- molecular formula: CioHg04

-molecular weight: 192.170800

- Structure of formula (XII), the cohesive energy and solubility parameter were determined using the direct and molar attraction constant contribution methods. The molar volume was determined to be 144.24 cm ³ /mol at 298 °K

- 41 was used. See Van Kreleven, DW and Hoftyzer, PJ, J. Appl. Polymer Sci., 13th ed., p. 871 (1969); and Van Kreleven, DW, Properties Of Polymers, 3rd ed., Elsevier Science Publisher (1990). The method uses the Group contribution to the molar volume of the amorphous polymer, then to the crystalline polymer in ^cm3 /mol (g basis). This is a set of data from four methods: two for the calculation of the cohesive energy according to Bunn, CW, J. Polymer Sci., vol. 16, p. 323 (1955), and Hostyzer, PJ and Van Kreleven DW, International Symposium On Macromolecules (IUPAC), Paper No. IIIa-15 (1970); and two for the calculation of the attraction constant (F) according to Small, PA, J. Appl. Chem., 3, p. 71 (1953), and Van Kreleven, DW, Fuel, 44, p. 236 (1965). The Bunn method is valid only at the boiling point, while the others are used at 298 °K.

The solubility parameter (Van Kreleven 1) of REVPET was determined to be 20.5283 J ^1/2 /cm ^3/2 , the attraction constant F (Van Kreleven) = 2961 (J cm ³ ) ^1/2 /mol (where J = Joule and cm = centimeter), and the cohesive energy Econ(Van Kreleven) = 60784.3 J/mol, where the solubility parameter = (Econ/niole volume) ¹⁷² , and EcoH ⁼ F ^1/2 /mol volume. The solubility parameter of unmodified PET is the same: 20.5283.

At the end of our detailed description, in Appendix A (before the claims), there is a sample output data generated by the Polymer-CAD program for the PET with the indicated structure. The data obtained include the volumetric properties; thermal properties; glass transition temperatures; cohesive energy and solubility; molar refraction and refractive index; electrical properties; magnetic properties; mechanical properties; acoustic properties; permachor and permeability; and thermal decomposition temperatures. Similarly, in Appendix B, we have summarized the data for REVPET.

Based on the high similarity in the solubility parameters of the oxygen scavenging polymer and the PET polymer, greater compatibility of the polymers is expected.

- 42 It is preferred that the solubility parameter of the polymers is within 3 units, and more preferably within 1 unit, as determined by the above software program (Van Kreleven 1). Appendix C contains a list of solubility parameters (SOL) and other properties of the various polymers. As discussed above, PET and REVPET have the same solubility parameter value (20.53). Modified REVPET has 20.18. In contrast, MXD-6 nylon has a much higher value of 26.8, which is well outside the preferred range of 3 units and shows that this polymer is much less compatible with PET.

The polymers falling within the preferred 3 units are:

REVPET (Figure 1B);

modified REVPET (Figure IC);

distyrol glycol/diphenic acid/glutaric acid (Figure 1D);

Bis A epoxy/adipic acid (Figure 1E); styrene oxide/adipic acid (Figure 1F); Bis A acetate/adipic acid (Figure 1J); Bis A acetate/suberic acid (description, Figure 1J); styrene oxide/succinic acid (description, Figure 1J); distyrol oxide/adipic acid (description, Figure 1J); distyrol glycol/succinic acid (description, Figure 1J); and cyclic Bis A caprolactone ester (Figure 1K).

Determination of oxygen uptake

The invention aims to provide an oxygen absorber that can be effectively used in the everyday packaging of food, soft drinks and other products. It is particularly useful in the packaging of products such as beer, which quickly loses its flavor due to oxygen migration. This is also true for products such as citrus products, tomato-based products and aseptically packaged meat. To

- 43 is also suitable for making carbonated soft drink containers. Depending on the application, a specific absorption rate may be desirable or necessary, as described below.

The term “oxygen uptake rate” in this context refers to the amount of oxygen absorbed by the packaging structure, expressed in nanograms (ng) of oxygen/surface area of packaging material (cm ² )/day (i.e. ng/cm ² /day). Accordingly, as the surface area of the packaging increases, the oxygen uptake capacity of the packaging must also increase to maintain the same rate. Also, because beer is more sensitive to oxygen than fruit juice, for a similar size package, the oxygen uptake rate of a package intended for storing beer should be higher than the oxygen uptake rate of a package intended for storing fruit juice. The oxygen uptake rate of the package should be at least 5 ng/cm ² /day, and more preferably at least 30 ng/cm ² /day.

The term "absorption performance ratio" as used herein refers to the ratio of the oxygen permeability (permeability) of a closure made of only an aromatic polyester to the oxygen permeability of a package containing both a polyester and an aromatic ester oxygen-absorbing polymer of the invention, for a package of the same size and shape (same dimensions). For example, a single-use [e.g., 250-373 g (8-12 ounce)] beer bottle should have an absorption performance ratio of at least 4, more preferably 10 or greater. A single-use juice bottle [e.g., 250-373 g (8-12 ounce)] should have an absorption performance ratio of at least 1.5, more preferably at least 4, and most preferably at least 8.

A package is designed for a storage period of several weeks or months. For example, a typical requirement for beer is 1 ppm oxygen over a storage period of 112 days. A one-liter bottle can therefore contain a total of 1000 pg O ₂ over the intended storage period (1 ppm = 1 pg/cm ³ volume).

A single-layer, clean (unused) bottle-grade PET control container was prepared with a thickness of 330 µm (13 mil), a diameter of 6.6 cm (2.6 in), and a height of 12 cm (4.75 in). The estimated surface area of the container was approximately (387 m ² , 60 square inches). The container was filled with oxygen-free water. The rate at which oxygen diffused from the outside into the interior of the container was measured using an oxygen analyzer (LC700F model, serial number 695935, distributed by Mocon Inc., Minneapolis, Minnesota USA) according to ASTM S1307-90 test method. The oxygen permeation rate for this control container was 30,000 ng/package/day. Dividing the oxygen permeation rate by the surface area gave an oxygen permeation rate of 77 ng/cm ² /day. Typically, a package is designed to match the oxygen uptake rate to the oxygen penetration rate. In this example, a bottle made of single-layer REVPET of the same size has an oxygen penetration rate of 1 ng/ ^cm2 /day or less. For this package, 1 ng/ ^cm2 /day corresponds to 70 ppb of oxygen accumulating over 112 days. This is a 77-fold improvement over the control bottle.

If PEN is used instead of PET, the oxygen penetration rate of the control bottle is 6000 ng/packaging/day, or 18.6 ng/cm ² /day.

If desired, a different catalyst can be used to increase the oxygen scavenging rate of the oxygen scavenger. For example, Eastman 9921 is a PET polymer that contains residual cobalt; cobalt is used as a catalyst in the production of PET. It has been found that the residual cobalt will act as an oxygen scavenging catalyst when the PET polymer is blended or copolymerized with a different oxygen scavenger composition. Eastman 9921 is available from Eastman Chemical, Kingsport, Tennessee, USA.

- 45 Similarly, we have found that the presence of water increases the oxygen uptake rate. One anticipated use of the container is for storing aqueous liquid products, where this improvement will certainly occur.

Pasteurization process

Known in the art, pasteurizable carbonated soft drink containers and bottles are typically made of glass or metal because they can withstand the high temperatures and high internal pressures during pasteurization. Figure 12 graphically depicts the temperature and pressure rise over time during conventional wet pasteurization of a [500 g (16 ounce)] glass bottle filled with 2.5 volumes of carbonated fruit juice; “2.5 volumes” means that the volume of carbon dioxide is 2.5 times the volume of the liquid at 0°C and atmospheric pressure. The typical pasteurization process, as shown in Figure 12, consists of five steps:

(1) immersion in the 43°C bath 1 for approximately 12.5 minutes to allow the bottle and its contents to adopt the temperature of the bath 1;

(2) immersion in the 77°C bath 2 for 12.5-21 minutes to allow the bottle and its contents to adopt the temperature of the bath 2;

(3) immersion in the 73°C bath 3 for 21-31.5 minutes to allow the bottle and its contents to adopt the temperature of the bath 3;

(4) immersion in the 40°C bath 4 for 31-43 minutes to bring the bottle and its contents down to the temperature of the bath 4; and (5) immersion in the cooling bath 5 for 43-60 minutes to cool the bottle and its contents to about 10°C.

The temperature curve 12 shows that the cylinder and its contents remain above 70 °C (in bath 3) for roughly 10 minutes, during which time the internal pressure increases significantly to 1 · 10 ⁶ N-m' ² (110 psi). This is approximately

- 46 A period of 10 minutes at 70-75°C ensures effective sterilization for most carbonated soft drinks, including those containing 100% fruit juice. The glass bottle can withstand these temperatures and pressures without deformation.

A plastic bottle containing the oxygen-scavenging polymer of the invention can be made to withstand the temperature/pressure conditions of pasteurization by using one or more of the following features: using a polyester with a higher Tg (better heat resistance); designing the bottle to meet the requirements; using heat-induced crystallization; using a crystallized neck end; etc.

Several embodiments of the invention have been shown and described; it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention as defined in the claims.

- 47 Annex “A”

Name: FIVE

Formula: C1OH804

Molecular weight: 192.170800

Structure: Compound of formula (A)

Volumetric characteristics:

Using van der Waals volumetric contributions:

Used molecular weight Vw = 192.171 = 94.16 cm ³ /mol Va = 1.6 vW = 150.656 cm ³ /mol Density (a) Ve = 1.435 Vw Density (c) = 1.27556 gm/cm ³ = 135.12 cm ³ /mol = 1.42223 gm/cm ³

Using Van Krevelen molar volume contributions:

Used molecular weight Va = 192.171 = 144.24 cm ³ /mol Density (a) Ve = 1.3323 gm/cm ³ = 131.36 cm ³ /mol Density (c) = 1.46293 gm/cm ³

Using Fedors group contributions:

Used molecular weight Va = 192.171 = 120.6 cm ³ /mol Density (a) Thermal properties: = 1.59346 gm/cm ³

Using the Satoh-Shaw method:

Applied molecular weight = 192.171

Cps = 1.15262 J/(gmK)

- 48 Cpl = 1.58141 J/(gmK)

Transition temperatures:

Using Van Krevelen glass transition temperature contributions: Applied molecular weight = 192.171

Tg = 350.73 K

Using Van Krevelen's crystalline melting point contributions: Applied molecular weight = 192.171

Tm = 566.683 K

Cohesive energy and solubility:

Using direct and molecular attraction constant methods: Applied molecular weight =192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1 Ecoh (at Bunn Tb) = 46340 J/mol

Solubility parameter (at Bunn Tb) = 17.924 J ^A l/2 cm ^A 3/2 Ecoh (Hoftyzer & Van Krevelen) = 60340 J/mol

Solubility parameter (Hoftyzer & Van Krevelen) = 20.4531 J ^A l/2 cm ^A 3/2 F (small) = 3158 (J cm ³ ) ^A (l/2)/mol

Ecoh (small) = 69141.5 J/mol

Solubility parameter (small) = 21.8941 J ^A l/2 cm ^A 3/2

F (Van Krevelen) = 2961 (J cm ³ ) ^A (l/2)/mol

Ecoh (Van Krevelen) = 60784.3 J/mol

Solubility parameter (Van Krevelen) = 20.5283 J ^A l/2 cm ^A 3/2 Using Fedors group contributions: Applied molecular weight = 192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen 1 from Ecoh (Fedors) = 77820 J/mol

Solubility parameter (Fedors) = 23.2275 J ^A l/2 cm ^A 3/2

- 49 · ·· «· 9 **·1 • ·♦· · · · ·*·« «· ·♦··

Molar refractive index and refractive index:

Using Goedhart contributions:

Applied molecular weight =192.171

Applied molar volume

R (Lorentz & Lorenz) = 144.24 cm ³ /mol Van Krevelen from 1

Refractive index (Lorentz & Lorenz) R (Gladstone & Dale)

Refractive index (Gladstone & Dale)

R (Bird)

Refractive index (Vogel)

Electrical properties:

= 47.748 cm ³ /mol = 1.57624 = 83.082 cm ³ /mol = 1.576 = 299.48 g/mol = 1.55841

Using Van Krevelen contributions:

Applied molecular weight = 192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

P (Lorentz & Lorenz) = 64.3 cm ³ /mol

Dielectric constant (Lorentz & Lorenz) = 3.41306

P (Vogel) - 359.88 cm ³ /mol

Dielectric constant (Vogel) = 3.50704

Magnetic properties:

Using Van Krevelen diamagnetic susceptibility contributions:

Applied molecular weight =192.171

Molar diamagnetic susceptibility = 0.0001015 cm ³ /mol

Diamagnetic susceptibility = 5.28176e-007 cm ³ /gm

Mechanical characteristics:

using Rao & Hartmann contributions for the sound speed factor:

Applied molecular weight = 192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

UR = 8310 (cm ³ /mol)(cm/s) ^The l/3

TM = 6450 (cm ³ /mol)(cm/s) ^The l/3

Density = 1.3323 gm/cm ³

Modulus of elasticity:

Melt (K) = 4.87185e+0.10 dyn/cm ²

Shear (G) = l.06524e+0.10 dyn/cm ²

Elongation (E) = 2.97861e+0.10 dyn/cm ²

Poisson's ratio =0.398101

Acoustic characteristics:

using Rao & Hartmann contributions for the sound speed factor:

Applied molecular weight = 192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

UR =8310 (cm ³ /mol)(cm/s) ^A 1 /3

TM =6450 (cm ³ /mol)(cm/s) ^The l/3

Density = 1.3323 gm/cm ³

Speed of sound:

longitudinal (uL) =2173.2 m/s shear (uSh) = 894.174 m/s propagation (uext) = 1495.22 m/s

Permachor and permeability:

Using the Salamé Permachor process:

Applied molecular weight = 192.171

Permachor (pi) = 58.8

Nitrogen permeability = 7.64892e-016 cm ² /(s · Pa) at 298 K

Thermal decomposition temperatures:

Using Van Krevelen (1/2) decomposition temperature contributions:

Applied molecular weight = 192.171

Td(l/2) =718.111 K

The missing group before the characteristic indicates values.

Annex B

Name: REV PÉT

Formula: C1OH804

Molecular weight: 192.170800

Structure: Compound of formula (B)

Volumetric characteristics:

Using van der Waals volumetric contributions:

Applied molecular weight =192.171

VW

Va = 1.6 vW

Density (a)

Ve = 1.435 Vw

Density (c) = 94.16 cm ³ /mol = 150.656 cm ³ /mol = 1.27556 gm/cm ³ = 135.12 cm ³ /mol = 1.42223 gm/cm ³

Using Van Krevelen molar volume contributions:

Applied molecular weight = 192.171

Va = 144.24 cm ³ /mol

Density (a) = 1.3323 gm/cm ³

Ve = =131.36 cm ³ /mol

Density (c) = 1.46293 gm/cm ³

Using Fedors group contributions:

Applied molecular weight =192.171

Va = 120.6 cm ³ /mol

Density (a) = 1.59346 gm/cm ³

Thermal characteristics:

Using the Satoh-Shaw method:

Applied molecular weight = 192.171

Cps = 1.15262 J/(gmK)

Cpl = 1.58141 J/(gmK)

Transition temperatures:

Using Van Krevelen glass transition temperature contributions: Applied molecular weight = 192.171

Tg =110.76 F

Using Van Krevelen's crystalline melting point contributions:

Applied molecular weight = 192.171

Tm = 420.797 F

Cohesive energy and solubility:

Using direct and molecular attraction constant methods:

Applied molecular weight =192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

Ecoh (at Bunn Tb) = 46340 J/mol

Solubility parameter (at Bunn Tb) = 17.924 J ^A l/2 cm ^A 3/2

Ecoh (Hoftyzer & Van Krevelen) = 60340 J/mol

Solubility parameter (Hoftyzer & Van Krevelen) = 20.4531 J ^A 1 /2 cm ^A 3/2

F (small) = 3158 (J cm ³ ) ^A (l/2)/mol

Ecoh (small) =69141.5 J/mol

Solubility parameter (small) = 21.8941 J ^A l/2 cm ^A 3/2

F (Van Krevelen) = 2961 (LT · cm ³ )-(l/2)/mol

Ecoh (Van Krevelen) = 60784.3 J/mol

Solubility parameter (Van Krevelen) = 20.5283 LT ^A l/2 cm-3/2

Using Fedors group contributions:

Applied molecular weight =192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

Ecoh (Fedors) = 77820 J/mol

Solubility parameter (Fedors) = 23.2275 J ^A l/2 cm ^A 3/2

- 53 Molar refractive and refractive index:

Using Goedhart contributions:

Applied molecular weight

Applied molar volume R (Lorentz & Lorenz)

Refractive index (Lorentz & Lorenz)

R (Gladstone & Dale)

Refractive index (Gladstone & Dale)

R (Bird)

Refractive index (Vogel)

Electrical properties:

= 192.171 = 144.24 cm ³ /mol Van Krevelen from 1 — 47.244 cm ³ /mol

- 1.56883 = 82.242 cm ³ /mol

- 1.57017 = 299.88 g/mol = 1.55528

Using Van Krevelen contributions:

Applied molecular weight =192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

P (Lorentz & Lorenz) = 64.3 cm ³ /mol

Dielectric constant (Lorentz & Lorenz) = 3.41306

P (Vogel) = 359.88 cm ³ /mol

Dielectric constant (Vogel) = 3.50704

Magnetic properties:

Using Van Krevelen diamagnetic susceptibility contributions:

Applied molecular weight =192.171

Molar diamagnetic susceptibility = 0.0001015 cm ³ /mol

Diamagnetic susceptibility = 5.28176e-007 cm ³ /gm

Mechanical characteristics:

using Rao & Hartmann contributions for the sound speed factor:

Applied molecular weight = 192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

UR = 8310 (cm ³ /mol)(cm/s) ^The l/3

UH = 6450 (cm ³ /mol)(cm/s) ^A l/3

Density = 1.3323 gm/cm ³

Modulus of elasticity:

Melt (K) = 4.87185e+0.10 dyn/cm ²

Shear (G) = l.06524e+0.10 dyn/cm ²

Elongation (E) =2.97861 e+0.10 dyn/cm ²

Poisson's ratio =0.398101

Acoustic characteristics:

using Rao & Hartmann contributions to the sound speed factor: Applied molecular weight =192.171

Applied molar volume = 144.24 cm ³ /mol Van Krevelen from 1

UR = 8310 (cm ³ /mol)(cm/s) ^1/3

UH = 6450 (cm ³ /mol)(cm/s) ^A l/3

Density = 1.3323 gm/cm ³

Speed of sound:

longitudinal (uL) = 2173.2 m/s shear (uSh) = 894.174 m/s propagation (uext) = 1495.22 m/s

Permachor and permeability:

Using the Salamé Permachor process:

Applied molecular weight =192.171

Permachor (pi) =58.8

Nitrogen permeability = 7.64892e-016 cm ² /(s · Pa) at 298 K

Thermal decomposition temperatures:

Using Van Krevelen (1/2) decomposition temperature contributions: Applied molecular weight = 192.171 Td(l/2) = 645.597 F

The missing group before the characteristic indicates values.

- Annex 55 C

ALPHA in 20 \D 12 23 cd σ> 19 17 23 1—Monday 28 CD CD CARB 29 27 o 23 25 17 19 19 17 00 34 67 AROMA 39.6 39.6 Li 67 40 31 35 48 CS m 57 CD in 57 t CD o o o PERM Ό 2-15 4.6-15 4-16 7.8-15 2.9-15 5.4-15 1.8-15 2.9-15 7-15 1-14 10-15 3-17 7-20 9-18 1.6-13 CDEN 1,463 1,463 1,412 1.36 1.26 1.29 1.36 1.28 1.33 1.35 1.28 1.25 1.25 1.31 1.27 1,177 1.34 ADEN 1.33 1,332 1,284 1.22 cd 1.17 1.23 1.16 1.20 1.22 i * 1.16 1.13 £l‘l 8Tl 1.14 1,055 1.21 SOL 20.53 20.53 20.18 20.46 21.9 19.25 19.64 19.5 19.97 20.2 19.7 19.4 20 26.8 30.36 26.4 27.67 Öo) “1 260 214 195 256 238 155 184 199 224 194 276 259 292 266 156 70 36 T _G (°C) 72 43 35 103 71 27 41 09 73 m o\ 79 85 73 82 43 in Name PET REVPET modified REV PET distyrol glycol/diphenic acid/glutaric acid bis-A epoxy/adipic acid styrene oxide/adipic acid styrene oxide/succinic acid distyrol oxide/adipic acid distyrol glycol/succinic acid 4-(Acetyloxy)-benzenepropanoic acid bis-A-acetate/adipic acid bis-A-acetate/suberic acid cyclic bis-A-ester caprolactone MXD6 PVOH EVOH aliphatic polyketone Reaction scheme VI IB IC ID IE IF IC

- 56 - .· ··; .· : .

···· · · · ·· · ··· ··

Example 1: Example of calculating the weight % of AROM, CARB and ALPHA for REVPEN, molar mass = 242.

14C * 12 168

10H* 1 - 10 * 16 = 64

Compound with formula 242 (Ip)

AROM IOC + 6H = 126/242 = 52 %

CARB CO + CO = 56/242 = 23%

ALPHA (CH ₂ ) ₂ = 28/242 = 12 %

Example 2: Example of calculating the mass% of AROM, CARB and ALPHA

For polymer 1-J, molecular weight = 338.

21C* 12 =252

22H*1 = 22 * 16 = 64

Compound with formula 338 (2p)

AROM C ₆ H4 + C ₆ H4 + C(CH ₃ ) ₂ = 194/338 = 57 %

CARB CO + CO = 56/338 = 17%

ALPHA (CH ₂ ) ₄ = 56/338 = 17 %

Example 3: Example of calculating the weight % of AROM, CARB and ALPHA for MXD6 polymer, molecular weight = 246.

- 57 13C * 12 =156 18H* 1 = 18 2N * 36 = 72

Compound with formula 246 (3p)

AROM C ₆ H4 =76/246 =31 %

CARB CO + CO + CO *.5 + CO *.5 = 84/246 = 34 % the factor 1.5 was introduced because of the CO following each NH (see page 16)

ALPHA (CH ₂ ) ₄ + CH *.5 + CH *.5 = 70/246 = 28 % the factor 1.5 was introduced because of the CO following each NH (see page 16)

Claims (52)

PATENT CLAIMS 1. A transparent, oxygen-absorbing, multilayer product comprising: a bidirectionally oriented aromatic polyester polymer layer, and a layer comprising a catalyst and an aromatic ester absorbing polymer, said polymer comprising oc-hydrogencarbonyl oxygen-absorbing functional groups of the general formula (I), wherein n is 2 or more, and aromatic groups forming single or multiple aromatic rings in the main chain or side chain of the absorbing polymer; wherein the weight percentage ratio of α-hydrogen carbonyl groups to aromatic groups is selected to provide the desired absorption rate and a glass transition temperature, Tg, of the absorbing polymer that allows bidirectional stretching of both layers while bidirectional orientation of the aromatic polyester in the transparent product occurs. 2. The product of claim 1, wherein the absorbent polymer is selected from homopolymers, random copolymers, alternating copolymers and block copolymers. 3. The product of claim 1, wherein the aromatic polyester is selected from poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), poly(propylene terephthalate), poly(butylene terephthalate), poly(ethylene isophthalate), poly(cyclohexane dimethanol terephthalate), poly(propylene naphthalate), poly(butylene naphthalate), poly(cyclohexane dimethanol naphthalate), and copolymers and blends thereof. 4. The product of claim 3, wherein the aromatic polyester is selected from homopolymers and copolymers of PET. 5. The product of claim 3, wherein the aromatic polyester is selected from homopolymers and copolymers of PEN. 6. The product of claim 1, wherein the aromatic groups form a main chain ring structure selected from the groups of Figure II and a side chain ring structure selected from the groups of Figure III. 7. The product of claim 1, wherein the aromatic groups have one aromatic ring, two aromatic rings, or a fused aromatic ring. 8. The product of claim 1, wherein the aromatic groups are of formula (IV). 9. The product of claim 1, wherein the absorbent polymer has repeating units of formula (V) wherein n is 2 or more. 10. The product of claim 9, wherein n is 4. 11. The product of claim 1, wherein the absorbent polymer has repeating units of the REVPET type of formula (VI), wherein n is 2 or more. 12. The product of claim 1, wherein the absorbent polymer has repeating units of the REVPEN type of formula (VII), wherein n is 2 or more. 13. The method of claim 1, wherein the absorbent polymer contains aromatic groups AROM in an amount of 30-70% by weight. 14. The method of claim 1, wherein the absorbent polymer contains 5-30% by weight of CARB carbonyl groups. 15. The product of claim 1, wherein the absorbent polymer comprises 5-30% by weight of ALPHA a-groups. 16. The product of claim 1, wherein the absorbent polymer has repeating units consisting of one aromatic group, two ester groups, and two α-hydrogencarbonyl groups. 17. The method of claim 16, wherein n is 2, 3 or 4. 18. The product of any one of claims 1, 10, 11, 12 and 16, wherein n is 2. 19. The product of claim 1, wherein the absorbent polymer has repeating units of formula (VIII). 20. The product of claim 1, wherein the absorbent polymer has repeating units of formula (IX). 21. The product of claim 1, wherein the absorbent polymer has repeating units of formula (X). 22. The product of claim 1, wherein the absorbent polymer has repeating units of formula (XI). 23. The product of claim 1, wherein the absorbent polymer is a random condensation polymer made of ethylene glycol and a component of formula (1) and formula (2) wherein n is 2-10. 24. The product of claim 1, wherein the Van Kreleven solubility parameter of the absorbent polymer is within 3 units of the Van Kreleven solubility parameter of the aromatic polyester. 25. The product of claim 24, wherein the Van Kreleven solubility parameter of the absorbent polymer is within 1 unit of that of the aromatic polyester. 26. The product of claim 24 or 25, wherein the Van Kreleven solubility parameter (SOL) is determined as follows: SOL= (Ecoh/molar volume) ^1/2 where Ecoh is the cohesive energy determined by the formula Ecoh = F ^1/2 /molar volume, and F is the Van Kreleven attraction constant. 27. The product of claim 1, wherein the product has a H _T =[Y _d +(Yd+Y _s )]xl00 - It has a transparency ( _HT ) defined as 61 percent opacity to light passing through a given thickness of the product, and where Yj is the diffuse light passing through the thickness and _Ys is the reflected light passing through the thickness, and the diffuse and reflected transmitted light values are measured according to the ASTM D 1003 measurement method, where the _HT value is less than 10%. 28. The product of claim 27, wherein the H _T value is less than 5%. 29. The product of claim 1, wherein the bidirectionally oriented product has an average crystallinity of less than 15% according to ASTM 1505: % crystallinity is determined by the relationship = [(ds-da)/(dc-da)]xl00, where ds is the density of the product in g/cm ³ , da is the density of the amorphous polymer with 0% crystallinity, and de is the crystal density calculated from unit cell parameters. 30. The product of claim 29, having an average crystallinity of at least 20%. 31. The product of claim 1, wherein the Tg of the absorbent polymer is at least 10°C below the orientation temperature at which the aromatic polyester undergoes bidirectional stretching. 32. The product of claim 31, wherein the aromatic polyester PET and the absorbent polymer have a Tg of 70-85°C. 33. The product of claim 31, wherein the aromatic polyester PEN and the absorbent polymer have a Tg of 120-135°C. 34. The product of claim 1, wherein the crystallization rate of the absorbent polymer is no greater than the crystallization rate of the aromatic polyester. 35. The product of claim 1, selected from the group consisting of a film, a package, a preform, a blow molded container, and parts thereof. 36. The product of claim 35, wherein the product is a pasteurizer. - 62 wall section of a container under pressure. 37. The product of claim 1, which is a package having an oxygen uptake rate of at least 5 ng/cm ² /day. 38. The product of claim 1, which is a package having an absorbency ratio of at least 1.5. 39. The product of claim 1, which is packaging having an absorbency ratio of at least 4. 40. The product of claim 1, which is packaging having an absorbency ratio of at least 8. 41. The product of claim 1, which is packaging having an absorbency ratio of at least 20. 42. The product of claim 1, which is packaging having an absorbency ratio of at least 40. 43. The product of claim 1, which is a wall portion of a blow molded container, having: oxygen absorption rate of at least 5 ng/ ^cm2 /day; an average bidirectional stretch ratio of (9:1)-(15:1); and comprising at least one absorbent polymer layer and a catalyst, and at least one aromatic polyester polymer layer selected from PET, PEN, copolymers and blends thereof. 44. The product of claim 1, wherein the absorbent polymer has a molecular weight of at least 50,000 and a Tg of 70-135°C. 45. A transparent, oxygen-absorbing packaging material for storing oxygen-sensitive products, the packaging material comprising an absorbent polymer comprising an aromatic ester absorbent polymer and a catalyst, and a bidirectionally oriented aromatic polyester polymer, the absorbent polymer comprising aromatic groups and α-hydrogen carbonyl oxygen-absorbing functional groups, the packaging material comprising the polyester polymer and the absorbent - 63 contains one or more blends, copolymers or layered structures of polymers and has an absorption ratio of at least 10, where the ratio is defined as the ratio of the oxygen permeability of a barrier material made of only a polyester polymer to the oxygen permeability of an oxygen absorbing packaging material made of polyester and an absorbing polymer. 46. A transparent, oxygen-absorbing packaging material for storing oxygen-sensitive products, the packaging material comprising an absorbing polymer, which comprises an aromatic ester absorbing polymer and catalyst, and a bidirectionally oriented aromatic polyester polymer, the absorbing polymer comprising aromatic groups and α-hydrogen carbonyl oxygen-absorbing functional groups, the packaging material comprising one or more blends, copolymers or layered structures of the polyester polymer and the absorbing polymer, and the packaging having an oxygen absorption rate of at least 5 ng/cm ² /day. 47. A transparent, oxygen-absorbing packaging material for storing oxygen-sensitive products, the packaging material comprising an absorbent polymer comprising an aromatic ester absorbent polymer and catalyst, a bidirectionally oriented aromatic polyester polymer, the absorbent polymer comprising aromatic groups and α-hydrogen carbonyl oxygen-absorbing functional groups, the packaging material comprising one or more blends, copolymers or layered structures of the polyester polymer and the absorbent polymer, and the packaging having a shelf life of 112 days, allowing 1 ppm oxygen transmission. 48. A container having a transparent, multi-layered wall formed by bidirectional stretching, wherein the multi-layered wall comprises: an oxygen scavenger core layer, said material comprising a catalyst and an aromatic ester scavenger polymer comprising α-hydrogencarbonyl oxygen scavenger functional groups of the general formula (I), wherein n in the formula is 2 or more, and aromatic groups are present in the scavenger polymer - 64 form a single or multiple aromatic ring in their main chain or side chain; inner and outer intermediate layers of an oxygen barrier material; and inner and outer layers of a bidirectionally oriented aromatic polyester polymer; wherein the oxygen absorbing layer is formed by bidirectional stretching with polyester polymer layers and maintaining its transparency while providing an oxygen absorption rate of at least 5 ng/cm ² /day. 49. The packaging material or container according to any one of claims 46-48, wherein the aromatic polyester is selected from PET, PEN, and copolymers and blends thereof. 50. A method for producing a transparent, oxygen-absorbing, multilayer product, characterized in that an aromatic polyester polymer layer is produced; preparing an absorbing layer comprising a catalyst and an aromatic ester absorbing polymer comprising α-hydrogencarbonyl oxygen absorbing functional groups of the general formula (I) wherein n is 2 or more and aromatic groups forming a single or multiple aromatic rings in the main chain or side chain of the absorbing polymer; the weight percentage ratio of α-hydrogen carbonyl and aromatic groups is selected to adjust the glass transition temperature of the absorbent polymer; and the absorbent polymer layer and the polyester polymer layer are bidirectionally stretched to orient the polyester polymer layer bidirectionally and form a transparent product. 51. The product of claim 31, wherein the aromatic polyester PEN and the absorbent polymer are amorphous and have a Tg of 90-100°C. 52. The product of claim 1, wherein the layer comprising the catalyst and the absorbent polymer is a blend. - H The authorized person: Dr. Valyonné T. Elvira Patent Attorney