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Multilayered structuresRelated Patent Categories: Stock Material Or Miscellaneous Articles, Hollow Or Container Type Article (e.g., Tube, Vase, Etc.), Polymer Or Resin Containing (i.e., Natural Or Synthetic)Multilayered structures description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060194012, Multilayered structures. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 09/607,002, filed Jun. 29, 2000, which in turn is a divisional of U.S. application Ser. No. 08/989/807, filed Dec. 12, 1997, now abandoned, the disclosures of which are incorporated herein by reference in their entirety and to which priority and benefit under 35 U.S.C. .sctn. 120 is claimed to applications. BACKGROUND OF THE INVENTION [0002] The present invention relates to multilayer structures and methods for their preparation. Mote particularly, the invention relates to a multilayer structure having typical organic polymer layer(s) and dissimilar organic polymer layer(s) comprising a solventless waterless melt-processable acrylonitrile olefinically unsaturated polymer. It is understood that the term multilayer structure includes film, tape, sheets, containers, composites, articles that are extruded, injection-molded, compression molded m the like, structural body, and the like throughout this specification. [0003] No single polymer is capable of providing the chemical and physical properties that are required for various applications. It is useful to manufacture films, sheets, containers and packages from multilayer polymer materials because different polymer compositions provide different properties, and by combining different polymer layers the final product will have the benefit of the different polymer properties. Unfortunately, polymers that provide one kind of properties do not readily combine or adhere to polymers that provide other unique chemical and physical properties. [0004] Therefore, it would be advantageous to produce a multilayer material using dissimilar polymer layers. The present invention produces such a multilayer material. It would be further advantageous to produce a multilayer structure with an acrylonitrile olefinically unsaturated polymer. An acrylonitrile olefinically unsaturated polymer can be characterized by high resistance to abrasion, solvents, gas and UV light, hardness and high puncture resistance but lower water vapor resistance rate in comparison to other polymers such as polyolefins. An organic polymer can be characterized by high water vapor resistance rate, high tear strength, good heat seal and reduced shrink properties and low density, but has poor gas and solvent barrier properties and low UV resistance. The unique nitrile and organic polymer multilayer structure of the present invention provides improved gas/water barrier properties, resistance to chemicals, abrasion, solvents, and UV light improved rigidity, weatherability, wear performance and impact strength. These and other advantages will become apparent as the description of the invention proceeds. SUMMARY OF THE INVENTION [0005] The present invention is directed to a multilayer structure which displays improved resistance to abrasion, organic solvents, water vapor, gas (i.e., oxygen, carbon dioxide barrier properties), and UV light, as well as improved rigidity, impact strength, and wear performance. The multilayer structure comprises an organic polymer layer; and a solventless, waterless, melt processable acrylonitrile olefinically unsaturated polymer layer which comprises about 50% to about 95% by weight polymerizable acrylonitrile monomer and at least one of about 5% to about 50% by weight polymerizable olefinically unsaturated monomer. [0006] The present invention also provides a method for preparation of the multilayer structure which comprises the steps of providing an organic polymer; providing a solventless, waterless, melt-processable acrylonitrile olefinically unsaturated polymer comprising about 50% to about 95% by weight polymerizable acrylonitrile monomer and at least one of about 5%, to about 50% by weight polymerizable olefinically unsaturated monomer, and melt processing the polymeric components. The present invention may be used in a variety of molding methods, including extrusion, co-injection molding, multilayer extrusion molding, multilayer blow molding, injection molding, compression molding and the like. DETAILED DESCRIPTION OF THE INVENTION [0007] In accordance with the present invention, the multilayer structure comprises an organic polymer layer and a waterless, solventless melt-processable acrylonitrile olefinically unsaturated polymer (hereinafter "acrylonitrile olefinically unsaturated polymer") layer. The multilayer structure comprises at least two layers. [0008] The layer of organic polymer includes, but is not limited to, synthetic and natural polymers. The synthetic polymer includes, but is not limited to, polyolefins such as polypropylene, polyethylene and poly(4-methylpentene-1); polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN); polyamides (PA), including aliphatics and aromatics, such as nylons; polycarbonates such as polybisphenol-A carbonate (PC); polyimides (PI) such as polyetherimide aliphatic and aromatic; poly(amide-imides); poly(ester-imides); polystyrenes (PS); polyurethanes; polyvinyl chloride (PVC); polyketones; polyphenylene oxide (PPO); polyvinyl alcohol (PVA); polysulphone; liquid crystalline polymers such as copolyesters of hydroxy-benzoic acid with 2,6 naphthoic acid (Vectra); Kevlar.RTM. (available from DuPont); acrylonitrile containing polymers including a waterless, solventless melt processable acrylonitrile olefinically unsaturated polymer or an acrylonitrile containing polymer that is soluble in a solvent; and the like. [0009] The monomers employed in the organic polymer can be one monomer or a combination of monomers dependent upon the properties desired to impart to the end use of the multilayer structure. In a multilayer structure of three layers or more, the organic polymer is employed as either the outer layer m the inner layer of the structure, but not both. [0010] The other polymer layer is an acrylonitrile olefinically unsaturated polymer comprising an acrylonitrile monomer polymerized with at least one olefinically unsaturated monomer. The acrylonitrile olefinically unsaturated polymer comprises about 50% to about 95% by weight, preferably about 75% to about 93% by weight, and most preferably about 85% to show 92% by weight of polymerized acrylonitrile monomer, and at least one of about 5% to about 50% by weight, preferably about 7% to about 25% by weight, and most preferably about 8% to about 15% by weight of polymerized olefinically unsaturated monomer. The acrylonitrile olefinically unsaturated polymer is employed as the outer layer or the inter layer or both. [0011] The olefinically unsaturated monomer employed is one of more of olefinically unsaturated monomer with a C.dbd.C double bond polymerizable with an acrylonitrile monomer. The olefinically unsaturated monomer can be a single polymerizable monomer resulting in a co-polymer, or a combination of polymerizable monomers resulting in a multi-polymer. The choice of olefinically unsaturated monomer or a combination of monomers depends upon the properties desired to impart to the resulting multilayer structure and its end use. [0012] The olefinically unsaturated monomer generally includes, but is not limited to, acrylates such as methyl acrylates and ethyl acrylates; methacrylates, such as methyl methacrylate; acrylamides and methacrylamides and each of their N-substituted alkyl and aryl derivatives, such as acrylamide, methactylamide, N-methylacrylamide, N, N-dimethyl acrylamide; maleic acid and its derivatives, such as N-phenylmaleimide; vinylesters, such as vinyl acetate; vinylethers, such as ethyl vinyl ether and butyl vinyl ether, vinylamides, such as vinyl pyrrolidone, vinylketones, such ethyl vinyl ketone and butyl vinyl ketone; styrenes, such as methylstyrene, styrene and indene; halogen containing monomers, such as vinyl chloride, vinyl bromide, and vinylidene chloride; ionic monomers, such sodium vinylsulfonate, sodium styrenesulfonate, and sodium methyl sulfonate; acid containing monomers such as itaconic acid, styrene sulfonic acid and vinyl sulfonic acid; base-containing monomers, such as vinyl pyridine, 2-aminoethyl-N-acrylamide, 3-aminopropyl-N-acrylamide, 2-aminoethylacrylate, 2-aminoethymathacrylate; and olefins, such as propylene, ethylene, isobutylene. [0013] The multilayer structure is a minimum of two layers, or an unlimited number of layers, depending on the end use application. For example, a three-layer structure employs an inner layer of either the organic polymer or the acrylonitrile olefinically unsaturated polymer with the inner layer sandwiched therebetween the outer layers which is the organic polymer or the acrylonitrile olefinically unsaturated polymer, depending on the desired end use of the product. [0014] The polymer employed as the inner layer has a dissimilar composition or a dissimilar molecular weight or dissimilar theological properties in comparison to the polymer employed as the outer layer. The organic polymer and the acrylonitrile olefinically unsaturated polymer are thermally stable in relationship to each other. The organic polymer or the acrylonitrile olefinically unsaturated polymer is either the inner layer or the outer layer of the multilayer structure depending on the end use application and on the chemical and physical properties of the polymers such as melt flow and thermal characteristics, molecular weight, composition and the like. In the invention, the polymer employed as the inner layer of the multilayer structure is in the range of about 1% weight to about 99% weight, preferably about 5% weight to about 95% weight and more preferable about 10% weight to about 90% weight of the multilayer structure. The polymer employed as the otter layer in the multilayer structure is in the range of about 99% weight to about 1% weight, preferably about 95% weight to about 5% weight and more preferable about 90% weight to about 10% weight of the multilayer. The minimum amount of polymer for a layer is such that the polymer of the adjacent layer is not excessively exposed on the surface. [0015] The composition of the polymer used for the outer layer and the composition of the polymer used for the inner layer are prepared separately. The acrylonitrile olefinically unsaturated polymer is prepared by known polymerization processes. An exemplary method to make the melt-processable high-nitrile multi-polymer is described in U.S. Pat. No. 560,222 entitled "A Process for Making a Polymer of Acrylonitrile/Methacrylonitrile/Olefinically Unsaturated Monomers" and U.S. Pat. No. 5,618,901 entitled "A Process for Making a High Nitrile Multipolymer Prepared from Acrylonitrile and Olefinically Unsaturated Monomers," both incorporated herein by reference. The organic polymer is prepared by known polymerization processes. [0016] The multilayer structure is produced by a melt process. The thickness of the layers depend on the desired end use and is in the range of about 1 micron m any thickness depending on the end use application. The melt processing temperature is dependent on the melt temperature and the thermal degradation temperature of the composition of the outer layer polymer and the inner layer polymer. [0017] The acrylonitrile olefinically unsaturated polymer is melt processed in a waterless, solventless system; however trace amounts of water as an impurity may exist up to 3%, preferably 1% or less. A process for producing the multilayer structure of this invention comprises preparing separately the organic polymer and the acrylonitrile olefinically unsaturated polymer; combining the components; and extruding the polymer components through conventional means. [0018] In a one-step injection molding process, the various melt polymer components are combined in a mold and the mold allowed to cool. [0019] In a one-step extrusion process, the various melt polymer components are coextended in a conventional manner. [0020] Additional treatment may be employed to further modify the characteristics of the multilayer structure by the addition of reinforcement materials such as carbon fibers, glass fibers and the like; additives; Mustering agents; coloring agents and the like. It is understood that any additive possessing the ability to function in such a manner can be used so long as it does not have a deleterious effect on the properties of the nitrite multilayer structure. The invention is not limited to any specific lamination, extrusion, injection or molding techniques. Continue reading about Multilayered structures... Full patent description for Multilayered structures Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Multilayered structures patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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