MXPA99010528A - Amorphous silica in packaging film - Google Patents

Abstract

An article of manufacture includes an oxygen scavenger and an amorphous silica. The article can be in the form of e.g. a film or sealing compound. A package can be made from the article for containing an oxygen-sensitive article such as food. The amorphous silica reduces migration of odor causing by-products of the oxygen scavenging process. A method of making an article of manufacture having reduced migration of by-products of an oxygen scavenging reaction includes providing an article including an oxygen scavenger and an amorphous silica;and exposing the article to actinic radiation.

Description

AMORFA SILICA IN PACKING FILM FIELD OF THE INVENTION The invention relates generally to compositions, articles and methods for removing byproducts of an oxygen removal reaction. BACKGROUND OF THE INVENTION It is known that limiting the exposure of a product sensitive to oxygen maintains and increases the quality and "shelf life" of the product. In the food packaging industry, several means have been developed to regulate exposure to oxygen. These media include a modified atmosphere packaging (MAP) to modify the internal environment of a package: * gas cleaning, vacuum packing; vacuum packaging combined with the use of oxygen barrier packaging materials; etc. Oxygen barrier films and sheets of this type reduce or retard oxygen permeation from the external environment to the inner part of the package. Another method currently used is through an "active package". The inclusion of oxygen scavengers inside the cavity or internal part of the package is an active form of packaging. Typically, said oxygen scavengers are in the form of sachets containing a composition that removes oxygen through chemical reactions. One type of sachet contains iron compositions that are oxidize. Another type of sachet contains unsaturated fatty acid salts of a particular adsorbent. Another type of bag contains complex metal / polyamide. A disadvantage of the sachets is the need for additional packaging operations to add the sachet to each package. A further disadvantage that arises from the use of some sachets is that certain atmospheric conditions (eg high humidity level, low CO2 level) in the package are required in order for the removal to occur at an adequate rate. Another means of limiting exposure to oxygen includes the incorporation of an oxygen scavenger into the structure of the package. This achieves more uniform removal effects throughout the package. This can be especially important when there is a restricted circulation of air inside the package. In addition, such incorporation may offer a means to intercept and remove oxygen as it passes through the walls of the package (known herein - as an "active oxygen barrier") thus maintaining the lowest possible level of oxygen in the package. An attempt to prepare an oxygen removal wall includes the incorporation of inorganic powders and / or salts into the wall. However, the incorporation of these powders and / or salts causes degradation of the transparency of the wall and of the mechanical properties such as resistance to breaking off. In addition, these compounds can cause processing difficulties, especially in the manufacture of thin films or thin films within a film structure. In addition, removal rates in the case of walls containing these compounds are inadequate for some commercial oxygen removal applications, such as applications in which sachets are used. Another effort has focused on the incorporation of an oxygen removal system of metal-polyamide catalyst in the packaging wall, however, this system does not present an oxygen removal at a commercially feasible speed. Oxygen scavengers suitable for commercial use in films of the present invention are presented in U.S. Patent No. 5,350,622, and in U.S. Patent No. 5,211,875 a method for generally initiating the removal of oxygen is presented. Both applications are incorporated herein by reference in their entirety. In accordance with U.S. Patent No. 5,350,622, oxygen scavengers of an ethylenically unsaturated hydrocarbon and transition metal catalyst are made. The preferred ethylenically unsaturated hydrocarbon may be either substituted or unsubstituted. In accordance with what is defined here, a unsubstituted ethylenically unsaturated hydrocarbon is any compound that has at least one aliphatic carbon-carbon double bond and comprises 100% by weight of carbon and hydrogen. A substituted ethylenically unsaturated hydrocarbon is defined herein as an ethylenically unsaturated hydrocarbon having at least one aliphatic carbon-carbon double bond and comprises from about 50% to about 99% by weight of carbon and hydrogen. Preferred substituted or unsubstituted ethylenically unsaturated hydrocarbons are hydrocarbons having two or more ethylenically unsaturated groups per molecule. More preferably, it is a polymeric compound having 3 or more ethylenically unsaturated groups and a molecular weight equal to or greater than a weight average molecular weight of 1000. Preferred examples of unsubstituted ethylenically unsaturated hydrocarbons include, but are not limited to, diene polymers such as for example polyisoprene (for example, trans-polyisoprene) and copolymers thereof, 1,4-polybutadiene-cis and trans, 1,2-polybutadienes (defined as polybutadienes having 50% or more of 1,2 microstructure), and copolymers of them, such as, for example, styrene-butadiene copolymer. Such hydrocarbons also include polymeric compounds such as polypentenemer, polyoctenamer, and other polymers prepared by cyclic olefin metathesis; diene oligomers as for example squalene; and polymers or copolymers with unsaturation derived from dicyclopentadiene, norbornadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 4-vinylcyclohexene, or other monomers containing more than one carbon-carbon double bond (conjugated or not conjugated). Preferred substituted ethylenically unsaturated hydrocarbons include, but are not limited to, hydrocarbons with oxygen containing portions, such as esters, carboxylic acids, aldehydes, ethers, ketones, alcohols, peroxides, and / or hydroperoxides. Specific examples of hydrocarbons of this type include, but are not limited to, condensation polymers such as polyesters derived from monomers containing carbon-carbon double bonds, and unsaturated fatty acids, such as, for example, oleic, ricinoleic, ricinoleic dehydrated, and linoleic acids. , and derivatives thereof, for example, esters. Such hydrocarbons also include well-copolymer polymers derived from (meth) allyl acrylates. Suitable oxygen removal polymers can be made by trans-esterification. Such polymers appear in WO 95/026161, which is incorporated herein by reference in its entirety. The composition employed may comprise a mixture of two or more of the substituted ethylenically unsaturated hydrocarbons or insubstituted described here. While a weight average molecular weight of 1000 or more is preferred, an ethylenically unsaturated hydrocarbon with a lower molecular weight can be employed, provided that it is mixed with a film-forming polymer or polymer mixture. As will be apparent, ethylenically unsaturated hydrocarbons suitable for the formation of solid transparent layers at room temperature are preferred to remove oxygen in the packaging articles described herein. For most applications where transparency is required, a layer allowing a transmission of at least 50% of the visible light is preferred. When making transparent oxygen scavenging layers according to this invention, 1,2-polybutadiene is especially preferred for use at room temperature. For example 1, 2-polybutadiene can have mechanical properties, transparency and processing characteristics similar to those of polyethylene. In addition, this polymer retains its transparency and mechanical integrity even after the consumption of most or all of its oxygen capacity, and even when little or no resin is present. In addition, 1, 2-polybutadiene has a relatively high oxygen capacity and, once it has begun to remove, exhibits a relatively slow removal rate. elevated When oxygen removal at low temperatures is desired, 1,4-polybutadiene, and copolymers of styrene with butadiene, and styrene with isoprene are especially preferred. Such compositions are presented in US Pat. No. 5,310,497 issued to Speer et al., On May 10, 1994 and which is incorporated herein by reference in its entirety. In many cases it may be desirable to mix the aforementioned polymers with a polymer or ethylene copolymer. Other oxygen scavengers that may be employed in connection with this invention are presented in the United States patents. 5 / 075,362 (Hofeldt et al), 5,106,886 (Hofeldt al), 5,204,389 (Hofeldt et al.), And 5,227,411 (Hofeldt et al.), Which are incorporated herein by reference in their entirety. These oxygen scavengers include ascorbates or isoascorbates or mixtures thereof with one another or with sulfite, often sodium sulfite. Other oxygen scavengers that may be employed in connection with this invention appear in the patent publications PCT WO 91/17044 (Zapata Industries) and WO94 / 09084 (Aquanautics Corporation), both incorporated by reference here in their entirety. These oxygen scavengers include an ascorbate with a transition metal catalyst, the catalyst is a simple metal or salt or a complex compound or chelate of the transition metal; or a complex of transition metal or chelate of a polycarboxylic acid either salicylic or polyamine, optionally with a reducing agent such as ascorbate, where the transition metal or chelate complex acts primarily as an oxygen scavenging composition. Other oxygen scavengers that may be employed in connection with this invention appear in PCT patent publication WO 94/12590 (Commonwealth Scientific and Industrial Research Organization), which is hereby incorporated by reference in its entirety, these oxygen scavengers include at least one organic compound that can be reduced that is reduced under predetermined conditions, the reduced form of the compound can be oxidized by molecular oxygen, where the reduction and / or subsequent oxidation of the organic compound occurs independently of the presence of a transition metal catalyst. The organic compound that can be reduced is preferably a quinone, a photoreducible dye, or a carbonyl compound having absorbance in the UV spectrum. Sulfites, alkali metal salts of sulfites, and tannins, are also contemplated as oxygen scavenging compounds. As indicated above, the ethylenically unsaturated hydrocarbon is combined with a transition metal catalyst. While we do not limit ourselves to any theory In particular, the inventors note that the suitable metal catalysts are the catalysts which can easily interconvert between at least two oxidation states. See, Sheldon, R. A .; Kochi, J.K .; "Metal Catalyzed Oxidations of Organic Compounds" (Oxidations of Organic Compounds Catalyzed by Metals), Academic Press, New York 1981. Preferably, the catalyst has the form of a transition metal salt, the salt being selected from the first, second, or third transition series of the Periodic Table. Suitable metals include but are not limited to manganese TI or III, iron II or III, cobalt II or III, nickel II or III, copper I or II, rd II, III or IV and ruthenium II or III . The oxidation state of the metal when it is introduced is not necessarily the oxidation state of the active form. The metal is preferably iron, nickel or copper, with greater preference for manganese and especially cobalt. Suitable ions for the metal include, but are not limited to, chloride, acetate, stearate, palmitate, caprylate, linoleate, talate, 2-ethylhexanoate, neodecanoate, oleate or naphthenate. Particularly preferred salts include cobalt (II) 2-ethylhexanoate and cobalt (II) neodecanoate. The metal salt can also be an ionomer, in which case a polymeric counterion is employed. Such ionomers are well known in The technique. The ethylenically unsaturated hydrocarbon and transition metal catalyst can be further combined with one or more polymeric diluents, such as for example thermoplastic polymers usually employed to form film layers in plastic packaging articles. In the manufacture of certain packaging articles, well-known terpenetrants may also be used as polymeric diluent. Polymers that can be used as a diluent, include, but are not limited to, polyethylene terephthalate (PET), polyethylene (PE), low density or very low density polyethylene, ultra low density polyethylene, linear low density polyethylene, polypropylene, chloride polyvinyl, polystyrene, and ethylene copolymers such as ethylene-vinyl acetate copolymer, ethylene-alkyl (meth) acrylate copolymer, ethylene-(meth) acrylic acid copolymer, and ethylene-(meth) acrylic acid ionomer. Mixtures of different diluents can also be used. However, as indicated above, the selection of the polymeric diluent depends to a large extent on the article to be manufactured and on the final use. Said selection factors are well known in the art. Additional additives may also be included in the composition to provide desired properties for the particular article that is being manufactured. Such additives include, but are not necessarily limited to fillers, pigments, dyes, antioxidants, stabilizers, processing aids, plasticizers, flame retardants, anti-clouding agents, etc. The mixture of the components listed above is preferably achieved by melt mixing at a temperature within a range of 50 ° C to 300 ° C. However, alternatives, such as the use of a solvent followed by evaporation can also be used. The mixture can immediately precede the formation of the finished article or be preformed or precede the formation of the raw material or masterbatch for later use in the production of finished packing articles. Even though these technologies offer great potential in packaging applications, it has been found that oxygen scavenging structures can sometimes generate reaction byproducts that can affect the taste and odor of the packaged material (ie, organoleptic properties), or raise problems of regulations for food. These by-products may include acids, aldehydes, ketones and the like. The inventors have found that this problem can be minimized through the use of amorphous silicas that absorb reaction byproducts that cause odors. The silica Amorphous can be incorporated into one or more layers of a multi-layer film or container that includes an oxygen scavenging layer. However, a person of ordinary skill in the art will readily recognize that the present invention can be applied to any oxygen removal system that produces by-products such as acids, aldehydes, ketones, and the like. Definitions The term "film" (F) herein refers to a film, sheet, sheet, fabric, coating or the like that can be used to pack a product. For the purposes of this patent, no distinction is made between "absorption" processes and "absorption" processes. Both terms mean the sequestration of gas or liquid molecules on the surface or pores of a solid. The term "amorphous silica" refers herein to free or substantially free silica of crystalline Si02 tetrahedra, in accordance with that measured by x-ray diffraction. The term "oxygen scavenger" (OS) and the like refers here to a composition, article or the like that consumes, removes, or reacts with the oxygen of a given environment. The expression "Actinic radiation" and the like refers here to an electromagnetic radiation capable of causing a change chemical of any-shape, such as for example ultraviolet radiation or visible light, and an example is provided in U.S. Patent No. 5,211,875 (Speer et al). The term "polymer" and the like here denotes a homopolymer but also copolymers thereof, including bispolymers, terpolymers, etc. The term "ethylene alphaolefin copolymer" and the like denotes heterogeneous materials such as, for example, linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE) and very low density and ultra low density polyethylene (VLDPE and ULDPE), and homogeneous polymers such as for example ethylene-catalyzed polymers such as Exxon® materials available from Exxon, Tafmer® materials available from Mitsui Petrochemical Corporation, and Affinity® resins available from Dow Chemical Company. These materials generally include copolymers of ethylene with one or more comonomers selected from C4 to C14 alpha olefins such as, for example, butene-1 (ie, 1-butene), hexene-1, octene-1, etc., wherein the molecules of the copolymers comprise long chains with relatively few side chain branches or crosslinked structures. This molecular structure contrasts with conventional low or medium density polyethylenes having a greater number of branches than their respective counterparts. As used herein, the term "polyamide" refers to polymers having amide bonds along the molecular chain, and preferably, to synthetic polyamides, for example nylons. Furthermore, said term encompasses both polymers comprising repeating units derived from monomers such as caprolactam which are polymerized to form a polyamide, as well as copolymers of 2 or more amide monomers including nylon terpolymers also known generally as "copolyamides". "EVOH" refers herein to ethylene / vinyl alcohol copolymer. "EVA" refers herein to ethylene / vinyl acetate copolymer. "EBA" refers herein to ethylene / butyl acrylate copolymer. "EMA" refers herein to ethylene / methyl acrylate copolymer. "PP" refers here to polypropylene. "PE" refers here to polyethylene. SUMMARY OF THE INVENTION In one aspect of the invention, a manufactured article comprises an oxygen scavenger and an amorphous silicone. In a second aspect of the invention, a package comprises an oxygen-sensitive article, and a container in which the oxygen-sensitive article is placed, the container comprises an oxygen scavenger and a silica amorphous In a third aspect of the invention, a method for making a manufactured article comprises supplying an article comprising an oxygen scavenger and an amorphous silica; and the exposition of the article to actinic radiations. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood with reference to the drawings in which Figures 1 to 4 are schematic cross sections of various embodiments of a film of the present invention. DESCRIPTION OF THE PREFERRED MODALITIES The invention can be used to produce various manufactured articles, compounds, compositions of matter, coatings, etc. Two preferred forms are composed of seal, and flexible films, both useful in the packaging of food and non-food products. It is known to employ seal compounds in the manufacture of gaskets for the market of rigid containers. Large large diameter joints are typically made using a liquid plastisol. This plastisol is a liquid, highly viscous suspension of polymer particles in a plasticizer. In the manufacture of metal or plastic caps, and the like, this liquid plastisol is applied to the ring of a container such as a jar, and the container with the plastisol applied is "flow-fed" in an oven for the purpose of solidify the plastisol in the meeting. The result is a joint that forms around the container ring. Smaller gaskets are typically made for use in beer bottles. A polymer melt is applied by means of cold molding on the entire inner surface of the crown. Both polyvinyl chloride are used (PVC) like other polymers in this application. Discs for plastic lids are typically made by taking a strip of joint material and making discs, and inserting the discs into the plastic lid. In all these applications, the use of an oxygen scavenger and an amorphous silica beneficially offers the removal of oxygen from the internal environment of the container, while controlling the undesirable byproducts of the oxygen removal reaction. Thus, in accordance with this invention, a gasket includes a polymeric composition, an oxygen scavenger, and an amorphous silica. With reference to Figure 1, a multilayer film 10 having layers 12 and 14 is shown. Figure 2 shows a multilayer film, with layers 12, 14 and 16. Layers 12, 14 and 16 are preferably polymeric The layer 12 comprises an amorphous silica. Preferred amorphous silicas are the silicas that have a pore diameter average within a relatively narrow distribution; relatively small pores; and very high surface areas. The pore sizes (average pore diameter) are preferably less than 200 Á, more preferably less than 100 Á, and with special preference less than 50 Á. A preferred range of average pore diameter is between 20 and 200 A, with 20 to 35 A being especially preferred. Pore sizes up to 3 Á are possible, and this value represents the practical lower limit of pore size. Surface areas in accordance with that measured by BET methods (Brunauer-Emmett-Teller) are preferably greater than 200 square meters / g, more preferably greater than 400 square meters / g and with special preference, greater than 600 square meters / g . The practical upper limit of the surface area is approximately 1400 square meters per gram. When the optical characteristics of the resulting composition are important, sizes, particle means, as measured by light scattering methods, are preferably less than 20 - / + m, more preferably less than 10 - / + m, and especially less than 5 - / + m. The lower limit - practical in terms of the size of the particles is a particle large enough to have at least one pore. In the present invention some degrees of amorphous silica available in the Davison division of W.R. Grace &; Co.-Conn., And that are presented with older details here so-useful. The layer 14 comprises an oxygen scavenger, preferably a polymeric oxygen scavenger, especially one of the materials described herein. The layer 16 comprises an oxygen barrier material, such as, for example, an ethylene / vinyl alcohol copolymer (EVOH), Saran (for example, vinylidene chloride / vinyl chloride copolymer, or vinylidene chloride / sodium acrylate copolymer). methyl), polyesters, polyamide, metal, silica coating, etc. Figure 3 shows a laminated film in which a 3-layer film is adhered on a second film. Layers 32, 34 and 36 correspond functionally and as to their composition to layers 12, 14 and 16, respectively, of Figure 2, and layer 38 is an intermediate layer which may comprise any polymeric material such as polyolefin, more preferably ethylenic polymers such as ethylene / alpha-olefin copolymers and ethylene / unsaturated ester copolymers, more preferably ethylene / vinyl acetate copolymer. The layer 31 represents a conventional adhesive such as, for example, polyurethane adhesive. Figure 4 shows a laminated film in which a 4-layer film is adhered onto a second film. Layers 42, 44, 46 and 48 correspond functionally and in terms of their composition to layers 32, 34, 36 and 38, respectively, of figure 3. Layer 49 is a heat-sealable innermost layer which may comprise any polymeric material such as polyolefin, more preferably ethylenic polymers, such as for example ethylene / alpha-olefin copolymers and ethylene / unsaturated ester, for example ethylene / vinyl acetate copolymer. The layer 46 provides an oxygen barrier to the film structure, and is adhered to the layer 48 by means of conventional adhesive 41. This adhesive corresponds to the layer 31 of Figure 3, and is simply shown as a thick line . Example 2 and comparative examples 3 and 4 of Table 7 show examples of the laminated film of Figure 4. The invention will be better understood with reference to the examples illustrated below. Tables 1 and 2 identify the materials used in the examples. The remaining tables describe the films made with these materials, and organoleptic or migration data that result from the testing of some of these materials. Table 1 Material Source name Commercial description Si Sylobloc® 45 Grace amorphous silica Davison S2 Syloid® 63 Grace Amorphous silica Davison Syloid® 74 Grace Amorphous silica Davison Syloid® 234 Grace Amorphous silica Davison Syloid® 244 Grace Amorphous silica Davison Syloid® 308 Grace Amorphous silica Davison Sylobloc® 44 Grace Amorphous silica Davison Sylobloc®S200 Grace Amorphous silica Davison Syloid® 63 Grace Modified amorphous silica Davison Syloid® 74x6000 Grace Amorphous silica Davison 417-12 Colortech 80% masterbatch Concentrate of LLDPE and 20% of Zeolite UOP Abscents® 2000 ZSM-5 Grace zeolite Davison SY Grace zeolite Davison PEi Exact®4150 Exxon PE catalyzed by metallocene, an ethylene / 1-hexene copolymer with a density of 0.895 gm / cc PE2 Exceed®350D60 Exxon PE catalyzed by metallocene, an ethylene / 1-hexene copolymer with a density of 0.917 gm / cc PE-: SLP-9063 Exxon PE catalyzed by metallocene, an ethylene / 1-hexene copolymer with a density of 0.902 gm / cc PE4 Poli-et 1017 Chevron low density PE PES AC-9A Allied PE powder PPi Oppera® PP6102 Exxon polypropylene PP2 Escorene® Exxon polypropylene PD4182.E3 EVi LD-318.92 Exxon copolymer of ethylene / vinyl acetate with 9% by weight of comonomer vinyl acetate EV2 PE 1375 Rexene ethylene / vinyl acetate copolymer with 3.6% by weight of vinyl acetate comonomer EBi _ Lotryl ™ 30BA02 Atochem ethylene / butyl acrylate copolymer with 30% by weight of ADi Adcide ™ butyl acrylate copolymer 530 and Morton Silane blend, 9L23 International isocyanate, glycol and alkyl acetate OSi VECTOR ™ 8508-D Dexco styrene / Butadiene copolymer with 30% by weight of styrene comonomer and 70% by weight of butadiene comonomer TCi cobalt oleate Shepherd a transition metal catalyst TC2 cobalt stearate Shepherd a metal catalyst of transition Pli benzoylbiphenyl photoinitiator PI2 tribenzil- photoinitiator Trifenilbenzene AOi Irganox ™ 1076 Ciba- Antioxidant Geigy Fi 50m-44 Mylar ™ DuPont Polyethylene terephthalate film coated with sarán The average pore diameters of Table 2 were determined by nitrogen porosimetry. TABLE 2 Characterization of Potential Absorbers of Sub-products Average Average Volume Size surface area of pore diameter per BET of particulate pore (m2 / g) (+ m) ((ü1) cc / g) Sylobloc ™ 45 4.3 1.2 Syloid ™ 63 7.2 26 0.4 650-720 Syloid ™ 74 9 150 1.2 300-350 Syloid ™ 234 5.4 180 1.7 .. 380 Syloid ™ 244 4 1.6 Syloid ™ 308 4 1.2 Sylobloc ™ 44 4 1.5 Sylobloc ™ 3 0.6 500 S200 Syloid ™ 63 7 35 0.1 136 Modified Syloid ™ 4 74x6000 Abscents ™ 3-5 6.5 > 400 2000 ZSM-5 1-5 5.4 USY 1-5 7.4 Some materials were mixed together for some of the film structures, and these mixtures are identified as follows: SBi = 80% PEi + 16% PE3 + 4.0% S2. SB2 = 80% PE2 + 16% PE3 + 4.0% S2. SB3 = 80% PEi + 16% PE4 + 4.0% S2. SB4 = 80% "PE2 + 16% PE4 + 4.0% S2, ZBi = 80% PEi + 20% Zx, ZB2 = 80% PE2 + 20% ZL, ZB3 = 80% PEi + 12.8% PE3 + 3.2% PE4 + 4.0 % Z2, ZB4 = 80% PE2 + 12.8% PE3 + 3.2% PE4 + 4.0% Z2, ZB5 = 80% PEi + 12% PE4 + 4% PE5 + 2% Z2 + 2% Z3, ZB6 = "80% PE2 + 12% PE4 + 4% PE5 + 2% Z2 + 2% Z3. PPB2 = 60% PPi + 40% EBi. PPB2 = 60% PP2 + 40% EBi. OSBi = 50% EVi + 40% OSi + 8.83% EVi + 1.062% TC_ + 0.102% RI + 0. 01% AOi. OSB2 = 50% EVi + 40% OSi + 8.83% EVi + 1.062% TC2 + 0.102% PI2 + 0.01% AOx.

Sub-product control A gas space chromatography (GC) method was used to determine the ability of a material to observe aldehydes. Between 6.0 and 6.6 mg of a powdered silica was placed in the state in which it was received in a 22 mL upper space gas chromatography flask. 2 + L of a mixture of aldehyde in methanol was injected into each bottle. The mixture consisted of approximately 0.1% each of the indicated aldehydes. Control bottle contained only the mixture of aldehydes and did not contain silica powder. The flasks were kept at a temperature of 80 ° C for one hour before their injection into the gas chromatography unit. The data in Tables 3 and 4 show the percentage change in the concentration of aldehydes for each of the materials in relation to the control. TABLE 3 Percentage of aldehydes absorbed by candidate absorbers - Percentage change relative to control of aldehyde Material Propenal Hexanal Heptanal Octanal Total volatile Si "-80 -83 -97 -95 -69 S2 -63 -98 -99 -99 -47 S3 -67 -65 -85 -96 -54 S4 0 -65 -77 -91 -23 S5 0 -51 -77 -86 -22 s6 0 -57 -74 -83 -21 TABLE 4 Percentage of aldehydes absorbed by candidate absorbers Percentage change relative to the control of aldehyde Material Propenal Pentanal Hexanal Heptanal Octanal S7 0 -44 -64 -80 -89 S8 0 -67 -85 -96 -98 S9 -25 -45 -62 -80 -90 Sio -39 -53 -67 -83 -91 The data in Tables 3 and 4 indicate that Si and S2 are especially effective in absorbing a wide range of aldehydes as well as a substantial part of the methanol used as the carrier; that S4, Ss and S6 are less effective, particularly in the case of aldehydes of low molecular weights; and that there are clear differences in the ability of various silicas to absorb different aldehydes. Organoleptic In Table 5, a structure in the form of a sheet in 6 layers according to the invention, and two structures in the form of sheets of 6 comparison layers are presented. The 6-layer structures were each made by the lamination of a 5-layer film co-extruded, using a conventional adhesive, on a second film (= layer 6). TABLE 5 EXAMPLE STRUCTURE 1 SB? / PPB? / OSB? / SB2 / PE2 // AD; _ // F? COMP.1 ZB1 / PPB ../ OSB1 / ZB2 / ZB2 // AD1 // F1 COMP.2 ZB3 / PPB? / 0SB? / ZB4 / PE2 // AD; L // F? The size (in thousandths of an inch) of the present invention and of the comparative structures was: layer 1 layer 2 layer 3 layer 4 layer 5 adhesive layer 6 0.15 0.15 0.50 0.80 0.40 (minimum) 0.50 The films were activated by ultraviolet light in compliance with the process presented in U.S. Patent No. 5,211,875. The films were converted into packages in a Multivac® R 7000 packing machine. A Cryovac® T6070B film was used as the bottom fabric of the packages. Each package contained a slice of turkey. Each package was washed with a gas mixture consisting of 99% N2 and 1% 02. The packages were stored in the dark for 7 days at a temperature of 40 ° F. One panel rated the flavor of the turkey slices. The scale was located within a range of 1 to 6, with the number 1 indicating an extreme past taste and 6 indicating absence of past flavor. The average results appear in table 6. Table 6 ~ Film Average result 1 - 4.3 C0MP.1 3.1 COMP .2 3.2 In table 7, a 5-layer sheet-shaped structure according to the invention is presented, and two comparative structures in the form of a 5-layer sheet. The 5-layer structures were made by laminating a co-extruded 4-layer film, using a conventional adhesive, on a second film (= layer 5). Table 7 Example Structure 2 SB3 / PPB2 / OSB2 / SB4 // AD? // F? COMP. 3 PE1 / PE1 / OSB2 / EV2 // AD ..// F1 COMP. 4 ZB5 / PPB2 / OSB2 / ZBS // ADJ. / F1 The white (and approximately real) size (in thousandths of an inch) of each layer of the sheet structure of the invention and of the comparison sheets was: Capal capa2 capa3 capa4 adhesive capa5 0.15 0.15 0.50 1.00 (minimum) 0.50 The films were activated, converted into packages, and evaluated in the same way as described above for examples I, comparison example I, and comparative example 2. Table 8 summarizes the percentage of panel members who saw a result of 5 or 6 packed turkey slices. Table 8 Film Percentage of panel members who gave a result of 5 or 6 2 68% COMP. 3 6% COMP. 4 43% The data in table 6 and 8 show that amorphous silicas can significantly reduce the past taste caused by byproducts of the oxygen removal reaction. Films of the present invention can be made by any conventional means, including co-extrusion, lamination, extrusion coating, or corona bonding, and then optionally irradiated and / or oriented. They can be made heat shrinkable through orientation, for example, by means of trapped bubble methods or tension frame, if desired, in orientation ratios of 1: 2 to 1: 9 in the machine direction or in the transverse direction or in both directions. In the case of shrinkage applications, they may have a free shrinkage of at least 10%, more preferably at least 20%, and especially at least 30%, in either direction or in both directions at a temperature of 90 ° C. Gasket compositions of the present invention can be made by any conventional process, including, but not limited to, extrusion compounding for thermoplastic compositions and conventional mixing equipment for plastisol compositions. The gasket compositions of the present invention can then be formed into gaskets on lids, by any conventional process, including, but not limited to, cold-molding processes, "inserted discs, application of liquid plastisols through pressurized nozzles followed by solidification. in an oven, etc. Various changes and modifications can be carried out without departing from the scope of the invention defined below. For example, a mixture of several amorphous silicas can be used in the same article (for example, a film or seal compound). In films, even though it is preferred that the amorphous silica be used in the film and as packaging material in such a way that the amorphous silica is placed closer to the contents of the package, it may be a food product or any oxygen sensitive product, that the oxygen remover, there may be applications in which the amorphous silica is placed "outside" the oxygen scavenger, in such a way that the layer containing oxygen scavenger is closer to the content of a packaging made from the film, that the layer containing silica. The amorphous silica can be placed alternately on both sides of the oxygen scavenger. Likewise, within the same film, a first amorphous silica may be employed in a first layer, and a second amorphous silica, different from the first amorphous silica, may be employed in another layer of the film. Alternatively, the amorphous silica, in addition to the arrangements described above or instead of the arrangements described above, can be placed in the same layer or in the same layers as the oxygen scavenging material. Thus, by way of example, any of the layers 14, 34, and 44 of the examples and figures may include any suitable percentage, by weight of the layer of an amorphous silica or mixture of amorphous silicas. A preferred mixture of oxygen scavenger and amorphous silica in said blend layer is between 9% and 99.5% oxygen scavenger, and between 0.5% and 5% amorphous silica or amorphous silica mixture. Any suitable polymeric material can be employed in films containing amorphous silica, and are not limited to those presented herein. The amount of amorphous silica employed in a film of the present invention is preferably between 0.1% and 5% of the layer in which it is found. These percentages are based on amorphous silica per se, with adequate adjustment if the silica Amorphous is used as a master batch with another material such as polyethylene. Above 5% of the layer, the optical characteristics of the film can be compromised in some way, even though the film can still be used in many applications. In end-use applications where optical characteristics are not a critical feature of the package, such as opaque films or container seals, larger amounts of amorphous silica can be used in a beneficial manner. The amorphous silica presented here can be used with films or coatings, either in films or coatings, or it can be absorbed in several oxygen scavenging supports or for other uses, such as coating or coating in another object, or as bottle stopper or bottle liner, as an adhesive or non-adhesive insert, sealant, gasket, fibrous tissue or other inserts, or as a non-integral component of a rigid, semi-rigid or flexible container.

Claims (1)

1. CLAIMS A manufactured article that comprises a) an oxygen scavenger; and b) an amorphous silica The article according to claim 1, wherein the article comprises a film. The film of claim 2, wherein the film comprises: a) a layer comprising an oxygen scavenger; and b) a layer comprising an amorphous silica. The film according to claim 2, wherein the film comprises a layer comprising an oxygen scavenger and an amorphous silica. The film according to claim 2, wherein the oxygen scavenger comprises a material selected from the group consisting of: i) an oxidizable compound and a transition metal catalyst, ii) an ethylenically unsaturated hydrocarbon and a metal catalyst of transition, iii) an ascorbate, iv) an isoascorbate, v) a sulfite, vi) an ascorbate and a transition metal catalyst, the catalyst comprises a single metal or salt, or a compound, or chelate of the transition metal, vii) a complex of transition metal or chelate of a polycarboxylic acid, salicylic acid, or polyamine, viii) a reduced form of a quinone, a dye with photoreduction capacity , or a carbonyl compound that has an absorbance in the UV spectrum, and ix) a tannin. The film according to claim 2, wherein the amorphous silica has an average pore diameter of between 20 and 200 A. The film according to claim 2, wherein the amorphous silica comprises a synthetic amorphous silica. The film according to claim 2, further comprising an oxygen barrier layer. The film according to claim 2, further comprising a layer resistant to abuse. The film according to claim 2, further comprising a heat sealable layer. The film according to claim 2, further comprising an intermediate adhesive layer positioned between any of the abuse resistant layer and oxygen barrier layer, between the oxygen barrier layer and the layer comprising the oxygen scavenger, between the layer comprising the oxygen scavenger and the layer comprising the amorphous silica and between the layer that it includes the amorphous silica and the heat sealable layer. 12. The film according to claim 2, wherein the film is crosslinked. The film according to claim 2, wherein the film is oriented. 14. The film according to claim 2, wherein the film is heat shrinkable. 15. The article according to claim 1, wherein the article is in the form of a seal compound. 16. The seal kit according to claim 15, wherein the seal compound is in the form of a seal. 17. The gasket according to claim 16, wherein the gasket comprises a polymer, an oxygen scavenger and an amorphous silica. The gasket according to claim 16, wherein the gasket adheres a cover over a rigid or semi-rigid container. 19. A package comprising: a) an oxygen-sensitive article; and b) a container in which the oxygen-sensitive article is placed, the container comprises an oxygen scavenger and an amorphous silica 20. A method for making a manufactured article that it comprises: a) the supply of an article comprising an oxygen scavenger and an amorphous silica; and b) exposure of the article to actinic radiation.