MXPA00004066A - Method and apparatus for triggering an article containing an oxidizable organic compound - Google Patents

Abstract

A method includes the steps of providing an article comprising an oxidizable organic compound;passing the article (8) through a chamber (9);exposing the article, while in the chamber, to a source of actinic radiation (20) at a wavelength, intensity and residence time sufficient to provide the article with a dose of actinic radiation of at least 100 mJ/cm2, and exposing the article, while in the chamber, to a source of heat (34) sufficient to raise the temperature inside the chamber to at least 55°F. An apparatus is also disclosed.

Description

METHOD AND APPARATUS FOR ACTIVATING AN ARTICLE CONTAINING AN OXIDIZED ORGANIC COMPOUND Field of the Invention The invention relates in general to a method and apparatus for activating an article, especially an article containing an oxidizable organic compound. Background of the Invention It is well known that limiting the oxygen exposure of an oxygen sensitive article maintains and improves the quality and shelf life of the product. For example, by limiting the oxygen exposure of an oxygen-sensitive food product in the packaging system, the quality of the food product is maintained by minimizing nutrient loss, stopping enzymatic and lipolytic oxidation, preventing photolytic degradation, and reducing spoilage. . In addition, this packaging also keeps the product in stock for longer, thus reducing replenishment costs and costs incurred due to waste. _ A means to limit the exposure of a product to oxygen involves incorporating an oxygen scavenger into the packaging structure itself. This joins a more uniform purifying effect through the packaging. This can be especially important where there is restricted circulation of air inside the package. Furthermore, this incorporation can provide a means to intercept and purify oxygen as it passes through the walls of the package (here referred to as an "active oxygen barrier"), thereby maintaining the lowest possible oxygen level through the packaging. . Oxygen scavengers that can be incorporated into a film structure are described in U.S. Pat. Nos. 5,310,497, 5,350,622 and 5,399,289 (Speer et al.) And a method for initiating oxygen scavenging is generally described in U.S. Pat. No. 5,211,875 (Speer et al.). All of these four patents are incorporated herein by reference completely. According to the U.S. Patent No. 5,350,622 Oxygen scavengers are made from an ethylenically unsaturated hydrocarbon and transition metal catalyst. The preferred ethylenically unsaturated hydrocarbon may already be unsubstituted or substituted. The "oxygen scavenger" materials described by Speer et al. Are compounds that consume, deplete or reduce the amount of oxygen in a given environment. Other oxygen scavengers that can be incorporated into a film structure are described in the Patent Publication of the PCT (Patent Cooperation Treaty) WO 94/12590 (Commonwealth Scientific and Industrial Research Organization). These oxygen scavengers include at least one reducible organic compound, which is reduced under predetermined conditions, the reduced form of the compound is oxidized by molecular oxygen, wherein the reduction and / or subsequent oxidation of the organic compound occurs independent of the presence of a catalyst of transition metal. The reducible organic compound is preferably a quinone, a photo-reducible dye, or a carbonyl compound having absorbance in the UV spectrum. Oxygen scrubbers are useful in modified atmosphere (MAP) and barrier packaging environments. However, oxygen scavengers often require, or at least benefit from, stimulating to activate the oxygen scavenging properties. In the patent application of the U.S.A. Serial No. 08 / 691,829 filed August 2, 1996, incorporated herein by reference in its entirety, describes an apparatus that is beneficial for activating oxygen scavenging films. This apparatus is especially useful when used in a food processing plant or other facility where the activation apparatus is located near a packaging machine. Thus disposed, an oxygen scavenging film can be briefly activated before and probably just a few seconds before the film is used to pack a food or other oxygen-sensitive product. Most packaging areas in manufacturing or food production facilities such as meat processing plants, typically kept at a relatively low temperature, in the order of 4.44 to 10 ° C (40 to 50 ° F). The inventors have found that at these low temperatures, the induction period (the time between exposure of an article to actinic radiation or other firing mechanism, and the initiation of oxygen scavenging by the article) can be inconveniently long. Also, at these low temperatures, the speed at which the fired article will oxidize, can be inconveniently decreased. Packaging materials that contain an oxidizable organic compound that exhibit prolonged induction times must be kept by the processor in inventory for a sufficient period of time before use. In this way, a longer induction time can be costly to the processor, resulting in increased inventory. If the packing step occurs shortly after exposure to the activation medium, a delayed induction may mean that the oxygen sensitive product is placed in the package for some time without the benefits of oxygen purification. They have a very high affinity for oxygen, which can result in a storage life cut off for packaging and / or reduction in product quality, because the oxygen inside the package, or that enters the packaging of the external environment, can affect harmfully. The quality of the packaged product before the start of the oxygen purification, in this way, there is a competitive relationship for the oxygen available between the food and the packaging material, reducing the speed of oxygen purification can also have an adverse effect on the life in product storage and / or quality, if oxygen in the upper space of a package is not removed quickly enough Therefore, the harmful effects of this oxygen in the packaged product are increased (rancidity, deterioration due to the growth of micro-organisms, color change, etc.). A possible solution to these problems is to use more of the oxygen scavenger, or of being present, more of the or photoinitiator and / or catalyst, in the article. However, it has been found that although the additional loading of the oxygen scavenging material in the article can increase the purification capacity of the article, it does not appreciably increase the speed at which the article is purified. A second possible solution is the use of a tripping unit of the type generally described herein, and in the U.S. patent application. No. 08 / 691,829. However, using additional banks of UV lamps or otherwise increasing the level of incident actinic radiation in the film does not necessarily result in an increase in the debug rate in the activated article. It is also not convenient to make the largest activation unit. On the contrary, it is much more convenient for the processor to use a unit that is small in size, in order to save valuable space in the installation and in order to physically integrate the activating unit with an associated packing machine. The inventors have discovered that benefits can be obtained in period of induction and speed of depuration, by raising the temperature of the environment in which the activating unit is located. One way to take advantage of this discovery would be to increase the total ambient temperature of the processing / packing facility where activation and packaging operations occur. However, in the case of food and especially meat packing foods, this is not a feasible alternative due to the need to process and package these products in a relatively cold environment in general. The inventors have found that benefits can be obtained by providing a means for heating, with the means for heating disposed within an activation chamber. The invention provides an effective method and apparatus for activating an article containing an oxidizable organic compound, so as to result in a relatively short induction period, and improved oxygen scavenging rate, compared to a method and apparatus for oxygen scavenging without the benefit of the invention. Locating the means for heating inside the activation chamber provides the additional benefit of heating the radiation bulbs to reduce the start-up time and thus increase the total production speeds. The method and apparatus of preference allow the article to be activated immediately before use during packaging of an oxygen sensitive product; and preferably provide a compact activation means. Preferably, an apparatus is provided that is easily incorporated online into existing packaging systems to activate articles on or immediately before packing.

DEFINITIONS "Film" here means a film, laminate, sheet, weft, coating or the like, which can be used to pack a product. "Oxidizable organic compound", "oxygen scavenger" and the like here means a composition, compound, article or the like that can consume, exhaust or react with oxygen from a given environment. "Actinic radiation" and the like herein means electromagnetic radiation in any form such as ultra violet radiation or visible light, capable of causing a chemical change and is exemplified in the US patent. No. 5,211,875 (Speer et al.). "Polymer" and the like here mean a homopolymer, but also copolymers thereof, including bis-polymers, ter-polymers, etc. "Ambient temperature" means the ambient temperature of 20 ° to 25 ° C (68 ° to 77 ° F). SUMMARY OF THE INVENTION In a first aspect of the invention, a method comprising providing an article, comprises an oxidizable organic compound; pass the article through a camera; exposing the article while in the chamber, to a source of actinic radiation at a wavelength, intensity and residence time sufficient to provide the article with a dose of actinic radiation of at least 100 mJ / cm2; and exposing the article, while in the chamber, to a source of sufficient heat to raise the temperature inside the chamber to at least 12.8 ° C (55 ° F). In a second aspect of the invention, an apparatus comprises a camera, the camera comprises a means for emitting actinic radiation at a wavelength, intensity and residence time sufficient to provide an article, the article has an oxidizable organic compound, with an actinic radiation dose of at least 10 mJ / cm2, a means to raise the temperature inside the chamber at least to 12.8 ° C (55 ° F) and a means to supply or extract the article in the chamber. A preferred form of actinic radiation is UV light, and more preferably UV light with an approximate wavelength of 200 to 280 nm, and sometimes referred to as UV-C light. BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of the preferred embodiments of the invention follows, with reference to the accompanying drawings, in which: Figure 1 schematically illustrates an apparatus useful in connection with the present invention; Figure 2 schematically illustrates an apparatus useful in connection with the present invention incorporated in-line in a packaging system; and Figure 3 schematically illustrates a method and apparatus according to the invention. DESCRIPTION OF THE PREFERRED MODALITIES The invention can be used in connection with various articles of manufacture, compounds, compositions of matter, coatings, etc. Two preferred forms are seal compounds and flexible films, both useful in packaging food and non-food products. In addition to covers and closures, and traditional flexible film applications, the invention can be used in association with semi-rigid packaging, rigid containers, foamed and non-foamed trays, and cardboard liners, in systems where an oxygen scavenger has been activated . It is known to use seal compounds in the manufacture of packaging for the market of rigid containers. Large, large diameter gaskets are typically made using liquid plastisol. This plastisol is a highly viscous liquid suspension of polymer particles in a plasticizer. In the manufacture of caps, metal or plastic covers, and the like, this liquid plastisol is applied to the ring of a container such as a jar and the container with the applied plastisol, is "melted" in an oven, to solidify the plastisol in a package. The result is a package formed around the container ring. Smaller packages are typically made to be used in bottle caps. A fusion of polymers is applied by cold molding to the entire interior surface of the lid. Poly (vinyl chloride) (PVC) and other polymers are used in this application. Discs for plastic caps, typically they are made by taking a tape of packaging material and producing discs and inserting the discs in the plastic lid. In these applications, when an article comprising an oxidizable organic compound is to be activated by exposure to actinic radiation, heating the article during activation may beneficially improve the oxygen scavenging rate of the activated article. The invention can be used in the packaging of a wide variety of oxygen sensitive products including fresh red meat such as beef, pork, veal and lamb, smoked and processed meats such as sliced turkey, pepperoni, ham and Bologna sausage, vegetable products such as tomato-based products, other food products, including baby foods, beverages such as beer and products such as electronic components, pharmaceuticals, medical products and the like. The invention easily adapts to various vertical form-and-seal filling lines (VFFS = Vertical Form-Fill-and-Seal) and form filling and horizontal sealing (HFFS = Horizontal Form-Fill-and-Seal) . The invention is also adapted to be used in connection with shrinkable film type packaging equipment. A method and apparatus for activating oxygen scavenging film are provided, wherein a period of induction of the after-activation film can be reduced to periods of preferably substantially less than one day, and wherein the activation can be preferably incorporated as a online stage, preferably by an end user of the oxygen scavenging film, in order to reduce inventory problems with respect to activated films. As used herein, the oxygen scavenging film refers to a film having a compound that consumes, depletes or reduces the amount of oxygen in a given environment to which the film is exposed. The method and apparatus for activating the oxygen scavenging film serve to activate the film, which leads to activation (usually within a relatively short period of time) of the oxygen scavenging capacity of the film. Films for use with the invention include an oxidizable organic compound and preferably include both an oxidizable organic compound and a transition metal catalyst. Optionally, the oxygen scavenging film may also include photoinitiator compositions, antioxidants and other additives, for example as described in US Pat. No. 5,211,875. Preferred films containing oxidizable organic compounds of ethylenically unsaturated or unsubstituted hydrocarbon unsaturated polymers, preferably have a molecular weight of at least 1,000. More preferably, the oxidizable organic compound is selected from the group consisting of styrene / butadiene copolymers, styrene / isoprene copolymers, polybutadiene, polyisoprene, and mixtures thereof. Films of the invention may also include ultraviolet stabilizers. The transition metal catalyst of the oxygen scavenger film is preferably a transition metal salt of cobalt, manganese or mixtures thereof. Other suitable transition metal catalysts are described in U.S. Pat. No. 5,211,875.

The transition metal catalyst and ethylenically unsaturated hydrocarbon can be further combined with one or more polymeric diluents, such as thermoplastic polymers, which are typically used to form film layers in plastic packaging materials. In the manufacture of certain well-known packaging materials, thermofixes can also be used as the polymeric diluent. Polymers that can be used as the diluent include, but are not limited to, polyethylene terephthalate (PET), polyethylene, low or very low density polyethylene, ultra low density polyethylene, linear low density polyethylene, polypropylene, polyvinyl chloride, polystyrene and ethylene copolymers such as ethylene vinyl acetate, ethylene alkyl (MET) acrylates, ethylene-(MET) acrylic acid and ethylene-(MET) acrylic acid ionomers.

Mixtures of different diluents can also be used. The selection of the polymeric diluent depends in part on the product to be manufactured and the final use. It has been discovered that exposing oxygen scavenging film to actinic radiation at a certain wavelength, intensity, residence time and film distance, in an environment at a temperature of at least 12.8 ° C (55 ° F), results in activating the oxygen scavenging properties of the film in a relatively short period of time, i.e. the induction period. UV light, and more preferably UV light of germicidal wavelengths (UV-C light), has been found particularly effective in activating oxygen scavenging films. Preferred wavelengths are between 200 nm and 280 nm, such as 254 nm. Optimum wavelengths can be determined depending on the composition of the particular purifying resin and (if present) catalyst and photoinitiator. As described in the patent application of the U.S.A. Serial No. 08 / 691,829 fully incorporated herein by reference, oxygen scavenging films to be activated, exposed to actinic radiation at the desired wavelength, at a density and residence time sufficient to provide the film with a radiation dose actinic of at least 100 mJ / cm2, preferably at least 200 mJ / cm2, more preferably between 300 and 1600 mJ / cm2 and in particular between 400 and 800 mJ / cm2. It has been found that, within this range, different doses of actinic radiation, combined with an environment at a temperature of at least 12.8 ° C (55 ° F), beneficially affect the rate of film clearance after activation. Preferred temperatures are between 12.8 ° and 49 ° C (55 ° and 120 ° F) such as between 15.6 ° and 37.8 ° C (60 ° and 100 ° F) and between 18.3 ° and 26.7 ° C (65 ° and 80 ° F) ) such as 21 ° C (70 ° F). All values between 12.8 ° to 49 ° C (55 ° and 120 ° F) are incorporated here as if they were established individually. The practical upper temperature limit depends on the residence time of the film in the chamber. For typical packing operations, it is expected that 49 ° C (120 ° F) represents the upper temperature limit for the interior of the chamber. Higher temperatures can be used for short residence times, but it will be appreciated that at higher temperatures, physical damage to or deterioration of the film may occur, especially during prolonged exposure of the film to high temperatures. The intensity and residence time of actinic radiation can be used to provide the desired dose for a particular film. It is preferred to expose film to be activated by actinic radiation at an intensity of at least 0.8 mW / cm2, more preferably at least 2.0 mW / cm2. In order to provide film paths that are not very long, film to be activated is more preferably exposed to actinic radiation at an intensity of between 3.0 and 10 mW / cm2, such as between 3.0 and 7.5 mW / cm2. This intensity is provided at a distance from the source of actinic radiation to the film preferably between 1 cm and 3 cm.

The desired dose of actinic radiation is provided to a particular film by traversing the film on a path having a particular length at which the film is exposed to actinic radiation. At intensities as set forth above, the oxygen scavenging film is usually activated on preferred film paths having a length of between 0.5 m and 12 m, preferably 2 to 4 m, and at an average path speed of the film over the trajectory between 0.5 m / minute and 30 m / minute, typically 1.2 to 4 m / minute. This procedure results in exposure times of the film to actinic radiation typically between 15 and 90 seconds. The wavelength, intensity and residence time of actinic radiation described above, have been found to activate the oxygen scavenger film at excellent oxygen scavenging rates, and with very small or negligible induction period, thereby allowing the The method of the present invention is incorporated in-line into existing packaging methods, such that the oxygen scavenging film can be activated at or shortly before packing, and overcome the problems concerning storage and inventory of oxygen scavenging films. activated. Oxygen purification films activated in this way exhibit oxygen purification rates depending on the formulation and type of packaging to which the film is applied between 1 cc / m2 / day and 100 cc / m2 / day at temperatures of 4.44 ° C (40 ° F) when measured 4 days after activation. For modified atmosphere packaging (MAP = Modified Atmosphere Packages) that have a modified atmosphere upper space (MAP, 1-2% of 02) the activated oxygen scavenging film exhibits an oxygen purification rate between 20 and 60 cc / m2 / day at 4.44 ° C (40 ° F) when measured 4 days after activation, thus removing oxygen from the upper space of this package in order to reduce or eliminate adverse effects on the product packaged there. The present invention can be used in a variety of packaging environments. For example, in addition to its use in MAP packaging, it can be used in connection with packaging, including rigid containers, which have an unmodified internal packing environment, ie atmospheric air. The packaging film can either be an oxygen barrier film, or a film with a relatively high oxygen transmission. The invention can also be used in connection with packaging, including rigid containers having an internal packing environment with an initially high amount of oxygen, for example higher than that present in atmospheric air. Here again, the packaging film can either be an oxygen barrier film or a film with a relatively high oxygen transmission. In these alternate packaging systems, the final oxygen content of the internal packing environment may be greater than 0.5% oxygen, yet still offer benefits to the packer, depending on the packaged product, the nature of the packaging process and other factors. In some cases, the invention can be used to reduce or eliminate the need for gas flushing of a package, thereby saving the packaging step and reducing costs. The oxygen scavenger can serve both as an active barrier for oxygen entry from the outside of the package and as an oxygen consumer present inside the package, that is, in the environment of the internal package. Activated oxygen scavenging films as set forth above for use in prolonged retention packages with high barrier, exhibit oxygen purification rates of preferably between 1 and 10 cc / m2 / day when measured at room temperature, and 30 days after activation, thus providing additional oxygen barrier in the oxygen barrier layers of the gasket to which the oxygen scavenger film is applied, this oxygen purification exists over a prolonged period of time. Activated oxygen scavenger films can be used to rapidly reduce the residual oxygen content of a refrigerated MAP package to less than or equal to 0.5%, preferably less than or equal to 0.1% in less than or equal to 7 days, preferably less that or equal to 4 days ideally as quickly as possible after packing the product. This allows packages that include the activated oxygen scavenger film to pack with an initial residual oxygen content of 1 to 2% or more. The oxygen scavenging film rapidly reduces the residual oxygen content to acceptable levels and packaging at a higher initial residual oxygen content allows for faster machine cycles, thus improving the performance of the product. Now with reference to the drawings, the method and apparatus for activating oxygen scavenging film according to the invention will be further described in a preferred embodiment. Figure 1 illustrates a self-activating unit 10 having an unwinding roller 12 for feeding film 8 to chamber 9, a series of rollers 14 defining a film path 16 through chamber 9, and a winding roller 18 to receive activated film for subsequent use. The chamber 9 includes a source of actinic radiation, for example a series of low pressure germicidal wavelength UV bulbs 20, arranged in banks 22 with the film path 16 arranged to pass a film with respect to the banks 22 in order to of exposing the film to the desired dose of UV-C light. The oxygen scavenging film may include a number of layers, with the oxidizable organic compound and the transition metal catalyst layer preferably disposed sideways. Multilayer oxygen scavenging films are described in U.S. Pat. No. 5,350,622. It is preferable to expose only the oxidizable organic compound and the transition metal catalyst side to the multilayer film, under UV-C light. Furthermore, it is preferred that any multilayer film layers that are between the UV-C light source and the oxygen scavenging film are effectively transparent at 254 nm. In this way, as illustrated in Figure 1, the film path 16 can be arranged to expose only one side of film to the banks 22 of bulbs 20, although optionally both sides of the film can be exposed to the bulbs. the film path 16 at a distance from the banks 22 of the bulbs 20 between 1 cm and 3 cm such as 2 cm. Figure 2 illustrates one embodiment of an activation unit 10, wherein the activation unit 10 is incorporated in-line in a packaging apparatus. The chamber 9 is positioned to receive the film 8 from the unwinding roller 12, to pass the film over the film path 16 to expose a source of actinic radiation, for example UV-C light and to feed the film, activated 28 directly to a unit of packaging, for example gas sealing / flooding matrices 24. The activated film 28 is immediately incorporated as a layer and packaging together with the formed web 26, supplied with other elements of the packaging structure. Gas sealing / flooding matrices 24 serve to apply the activated film 28 to the formed web 26 in order to provide packages 30 including the activated film. Optionally, the activation unit 10 can be provided with a detector unit 32 to verify the dose of UV-C light emitted by the bulbs 20. This allows the detection of defective or defective bulbs 20. The detector unit 32 for example can be a UV intensity or online display module (Eit, Inc; Sterling, VA), which have Standard UVI detectors from 250 to 260 nm. The detector unit 32 can be interlocked or operatively associated with a controller for the packaging line, such that the packaging can be automatically interrupted if the output of the UV-C light is insufficient. The bulbs 20 are preferably protected at an effective intensity or irradiance E less than or equal to 0.1 mW / cm2 and are preferably provided with a sleeve member (not shown) to protect the film in the film path 16 against contact with broken elements such as glass, etc. of the bulb 20, in case the bulb 20 breaks. The sleeve may be a shrinkable member or liner that is applied to the bulbs 20. The preferred sleeve is a sleeve of heat shrinkable FEP-Teflon ™. The bulbs 20 can be fluorescent tube type bulbs, which preferably have a width sufficient to extend beyond both sides of the width of a film to be treated. Bulbs having a width of preference between 91.44 and 121.9 cm (36 and 48") may be suitable for processing films with a width of up to 76.2 to 101.6 cm (30 to 40"). Suitable bulbs are sold by Voltarc under the designation of part UV-LUX GRFX 5194. The step of exposing oxygen scavenging film to actinic radiation can optionally be carried out in a stepwise process, wherein the film is exposed in a plurality of periods discrete time. For example, if the intended exposure time or residence time is to be 40 seconds, the exposure step can be carried out in a series of four exposure stages, each 10 seconds long, preferably with a range of two seconds between them. This stepwise exposure provides improved oxygen scavenging characteristics of the activated film in that manner. This embodiment is easily adapted to intermittent movement machines such as MULTIVACMR R7000 distributed by KOCH of Kansas City, Missouri. Figure 3 shows an activation unit 10 according to the invention, having an unwinding roller 12 for feeding the film 8 to a chamber 9, a series of rollers 18 defining a film path through the camera 9 of the activation unit , and an activated film 28 advancing out of the chamber 9 and towards the packaging line 36. The direction in which the film moves is illustrated by the arrows. In the packing line 36, the activated film 28 is used to pack an oxygen sensitive product, and the finished package is then advanced to a conveyor or other suitable means for further processing. The activation unit 10 includes a source of actinic radiation, such as a series of UV bulbs of low-pressure germicidal wavelength 20, with the film path that is arranged to pass a film relative to the bulbs 20 so as to exposing the film to the desired radiation dose such as UV-C light. Means 34 for raising the temperature inside the chamber are used to increase the temperature of the chamber 9 at least to 12.8 ° C (55 ° F) during the time when the film 8 is activated inside the chamber. Means for heating 34 may be any convenient means, including by way of example only, a commercial or consumer heated thermal or commercial blower, an infrared heater, a temperature controlled cartridge heater with a convenient air circulation system; a closed system for circulating hot water and exchanging heat with the interior atmosphere of the chamber; or any other convenient heating means. As illustrated in Figure 3, the particular heating means employed are a series of lamps or infrared bulbs (IR) 34 conveniently placed to effect heating of the lower chamber. In Figure 3, the IR bulbs are illustrated as darkened ellipses and the UV bulbs are illustrated as light colored ellipses. Those of skill in the art will appreciate that the relative type and placement of heating means employed in connection with the invention can be determined and optimized depending on considerations such as chamber size, type of actinic radiation employed, type of film activated, speed of desired depuration, desired induction time and the like. In the particular embodiment described in Figure 3, the IR bulbs 34 are interspersed with the UV bulbs that provide relatively uniform heating to the interior of the chamber, and thus to the film that is activated within the chamber. Whatever the heating means employed, care must be taken not to excessively expose the film to heat, such that the film is undesirably altered in form or function. Auxiliary fans 40 may be employed if it is desired to participate and / or distribute the heat generated by the heating means. The following examples are provided in order to further illustrate the advantageous features of the present invention. EXAMPLES Table 1 describes the formulation of the film in Example 1. This material is activated in an activation unit of the type described in Figures 1 and 3. The packages (10 cm x 10 cm x 3 cm) were made using a Multivac R7000 packaging machine, with T6070B, a standard laminate of Cryovac Division WR Grace & Co., as the training plot. The gaskets were flooded with a mixture of 1% 02: 99% N2. Samples were stored in corrugated boxes that are maintained at a temperature of approximately 4.44 ° C (40 ° F) until analysis. The percentage of oxygen was determined by a superior space purification test protocol (HST = Headspace Scavenging Test). In the HST protocol, following the packaging step, a 5 cm x 7.5 cm wall of .1524 mm (6 mils) vinyl tape was applied to each bag. A first group of bags was flooded with gas, with a pre-mixed gas to give a final volume of 300 to 350 cubic feet of gas. Pre-mixed gas (Sunox Inc. / Carlotte, NC) was generally 1% 02: 99% N2. These bags were used to determine the rate of oxygen scavenging. A second group of bags containing atmospheric air was made. These bags were used to determine oxygen purification capacity. Bags containing the 1% gas mixture of 02: 99% N2 were stored in corrugated boxes at either 22 ° C or 4.4 ° C. Gas samples were taken at the start immediately after packing, and every 24 hours later for up to 7 days. For bags containing atmospheric air, the amount of oxygen within the bags was determined every 7 days thereafter for up to 30 days. Gas samples of approximately 5.1 cc were removed from each bag with a 5-amp Hamilton gas tight syringe (VWR Scientific, Inc. / Atlanta, GA). A 22 gauge style 5 Hamilton needle was used to avoid microsegregation of the wall. When a gas sample is removed, the vinyl tape wall was punched once and immediately resealed with another piece of vinyl tape (2.5 x 2.5 cm). Successive gas samples are removed from an unperforated portion of the vinyl wall. A time delay between sample and injection was less than or equal to 2 seconds. For each gas sample, the needle was flooded with 0.1 cc of gas, immediately before the injection to the analyzer. 5 ce of the sample gas, then injected slowly into a Mocon LC-70F oxygen analyzer (Modern Controls, Inc. / Minneapolis, MN), at a rate of 1 cc / second. Data was recorded at 3 decimal places. The data was provided to an Excell spreadsheet (Microsoft Corporation / Redmon, WA) that automatically calculates the cleared 02 ce. Average speed, instantaneous speed and capacity. The speeds were expressed in cc / m2 / day, while the capacities were expressed in cc / m2 / mm (thousand). Typical values reported with: average speed 4 days at 4.4 ° C. Peak instantaneous speed, induction period (if available) and days at peak speed. Table 1 In Table 1: Fl = polyethylene terephthalate film coated with Saran (30 m-44 MYLARMR from DuPont). ADI = Adhesive that has a mixture of silane, isocyanate, glycol and alkyl acetate (ADCOTE ^ 530 and corrective 9 L23 of Morton International) PEÍ = low density polyethylene (P0LY-ETHMR 1017 of Chevron).

Zl = Master lot of 80% linear low density polyethylene (LLDEP) and 20% UOP ABS CENTSMR 2000 Zeolite) 10417-12 Colorteck zeolite concentrate OSI = styrene / butadiene copolymer with 30% by weight of the styrene comonomer and 70% by weight of the butadiene comonomer (VECTORHR 8508 -D of DEXCO polymers). EBA1 = ethylene vinyl acetate copolymer with a vinyl acetate content of 9% by weight of the polymer (ESCORENEMR LD-318.92 from EXXSON, PP1 = Polypropylene homopolymer (ESCORENEMR PP-4292.E1 from EXXSON. EBA1 = ethylene / butylacrylate copolymer with 30%). % by weight of butylacrylate copolymer (LOTRYLMR 307BA02 from Atochem.

LLDP? II = linear low density polyethylene, ie an ethylene / octene copolymer (D0WLEXMR 2244A from Dow). MBI = A composite master batch formulation: 88.3% EBAI, . 6% cobalt oleate, 1% benzoyl biphenyl, 0.1% IRGANOXMR 76, stabilizer. Table 2 illustrates the temperature / UV dose treatments. The effects of increased chamber temperature and increased UV dose were examined by heating the chamber using a Master Flow heat blower (Model AH-501, 260 ° C (500 ° F)) and irradiating the film with one or two banks of lamps.

Table 2. Temperature treatment / UV dose for cold activated Lidstock. Example Temperature Temperature Dose UVB chamber environment ° C / (° F) ° C / (° F) (mJ / cm2) 1-A Environment 17.78 (64) Without heat 26.11 (79) 800 1-B Cold 4.44 (40) Without heat 17.78 (64) 800 1-C Cold 7.22 (45) Without heat 25 (77) 1600 1-D Cold 5.56 (42) With heat 36.11 (97) 800 1-E Cold 5.56 (42) With heat 54.44 (130) 1600 the heat is transferred through the chamber using a shrinkable film dryer. a bench- 800 mJ / cm2. Two banks-1600 m / cm2. The debug results for this test are illustrated in Table 3. The results showed that either increasing the chamber temperature (compare Example 1-B with Example 1-D) or the UV dose at 1600 mJ / cm2 (compare Example 1-B with Example 1-C) significantly increased the clearance rates and reduced the induction times of activated material at cold temperatures. In addition, the use of both increases the heat and increases the UV dose (see Example 1E) reduced the induction time to less than 24 hours and raised the peak velocities closer to those obtained with purified film at room temperature (see Example 1 -TO) .

It can also be seen that the purification rates of either heated or highly dosed materials are similar to the velocities of material that was activated at ambient temperatures. a Average speed after 4 days b A data point In this way, it was observed that increasing the temperature of the chamber or increasing the UV dose increases the purification rates and reduces the induction time of cold activated films. In combination, heating and increasing the UV dose further optimized the induction time of these films. Another way of evaluating the effectiveness of the present method and apparatus especially when dealing with packages having an initial oxygen level of 1% or less, is to measure the volume of oxygen initially present in the package, and then the volume of oxygen present in the package, several days after packing. In this way, the present invention provides a method and apparatus wherein a package, having an initial oxygen content of 0.5% at 4.44 ° C (40 ° F) has a residual oxygen content, in 7 days after packing. between 20 and 30%, such as 22%, of the initial oxygen content of the package. The present also provides a method and apparatus wherein a package, which has an initial oxygen content of 1.0% at 4.44 ° C (40 ° F) has a residual oxygen content within 14 days after packing between 30 and 40%, such as 35%, of the initial oxygen content of the packaging. The present invention also provides a method and apparatus wherein a package, having an initial oxygen content of 1.0% at 4.44 ° C (40 ° F) has a residual oxygen content within 14 days after packing, from 5 and 15%, such as 10%, of the initial oxygen content of the package. All the values that fall between these established values are included here as they were expressly established.

For packages with a relatively high initial oxygen content, for example 21% oxygen (atmospheric air) the amount of oxygen scavenging material present in the packaging material will typically be the limiting factor for determining the residual oxygen present in the various packaging. days after activation. The invention is not limited to the illustrations described herein, which are considered simply susceptible to modification of shape, size, arrangement of parts and operation details.

Claims (20)

1. CLAIMS 1.- A method, characterized in that it comprises: a) an article comprising an oxidizable organic compound; b) pass the article through a camera; c) exposing the article, while in the chamber, to a source of actinic radiation at a wavelength, intensity and residence time sufficient to provide the article with a dose of actinic radiation of at least 100 mJ / cm2; and d) exposing the article, while in the chamber, to a source of sufficient heat to raise the temperature inside the chamber to at least 12.8 ° C (55 ° F).
2. 2. - The method according to claim 1, characterized in that the actinic radiation comprises UV light.
3. 3. The method according to claim 2, characterized in that the UV light has a wavelength between 200 and 280 nm.
4. 4. - The method according to claim 1, characterized in that the article is exposed to a source of actinic radiation at an intensity of at least 0.8 mW / cm2.
5. 5. The method according to claim 1, characterized in that the article is exposed to a source of actinic radiation at an intensity of between 3.0 and 10 mW / cm2.
6. 6. - The method according to claim 1, characterized in that the article is exposed to a source of actinic radiation at a distance of the article between 1 and 3 cm.
7. 7. - The method according to claim 1, characterized in that the article is exposed to a source of actinic radiation, at a sufficient intensity and residence time to provide the article with a dose of actinic radiation of between 300 cJ / cm2 and 1600 cJ / cm2.
8. 8. - The method according to claim 1, wherein the exposure stage further comprises exposing the article to the source of actinic radiation on a path between 0.5 m and 12 m and a speed of the article on the path of between 0.5 m / minute and 30 m / minute.
9. 9. The method according to claim 1, characterized in that the exposure step comprises exposing the article to the source of actinic radiation for between 15 and 90 seconds.
10. 10. The method according to claim 1, characterized in that the article comprises a film.
11. 11. - The method according to claim 1, characterized in that it comprises verifying the dose of actinic radiation emitted by the source of actinic radiation.
12. 12. - The method according to claim 1, characterized in that it comprises protecting the UV-C light source, in such a way that it has an effective irradiance E less than or equal to 0.1 mW / cm2.
13. 13. - The method according to claim 1, characterized in that the oxidizable organic compound has a molecular weight of at least 1,000, and is selected from the group consisting of ethylenically substituted unsaturated hydrocarbon polymers, ethylenically unsubstituted saturated hydrocarbon polymers and their mixtures
14. 14. - The method according to claim 1, characterized in that the transition metal catalyst is selected from the group consisting of cobalt transition metal salt, manganese transition metal salt and mixtures thereof.
15. 15. The method according to claim 1, characterized in that the activated article has a rate of oxygen purification of between 1 cc / m2 / day and 100 cc / m2 / day at 4 ° C.
16. 16. - The method according to claim 1, characterized in that the oxygen purification package has a residual oxygen content less than or equal to 0.5% in 7 days after packing.
17. 17. - The method according to claim 1, characterized in that the oxygen scavenging package has a residual oxygen content in 7 days after packing less than 40% of the initial oxygen content of the package.
18. 18. The method according to claim 1, characterized in that the exposure step comprises exposing the article to the UV-C light source in a plurality of discrete periods of time.
19. 19. Apparatus, characterized in that it comprises: a) a chamber, the chamber comprises a means for emitting actinic radiation at a wavelength, intensity and residence time sufficient to provide an article, the article has an oxidizable organic compound, with an actinic radiation dose of at least 100 mJ / cm2; b) means for raising the interior temperature of the chamber at least to 12.8 ° C (55 ° F); and c) means for supplying and extracting the article in the chamber.
20. 20. The apparatus according to claim 19, characterized in that the means for raising the temperature of the chamber are chosen from: i) a heated blower; ii) a heat gun; iii) an infrared heater; iv) a heater with controlled temperature cartridge, with an air circulation system; and v) a circumscribed heated fluid circulation system that exchanges heat with the interior atmosphere of the chamber.