MXPA97005538A

MXPA97005538A - Barrier of multiple layers for the humidity paraprobador of cell electroquim

Info

Publication number: MXPA97005538A
Application number: MXPA/A/1997/005538A
Authority: MX
Inventors: Treger Jack; Wei Guang
Original assignee: Duracell Inc
Priority date: 1995-01-23
Filing date: 1997-07-22
Publication date: 1998-02-01

Abstract

The present invention relates to an electrochemical cell having a condition tester of the cell, sensitive to humidity, and a moisture barrier, transparent to light, characterized in that the moisture barrier comprises a composite material on a polymeric substrate, the composite material comprises alternating layers of a water-insoluble inorganic material selected from the group consisting of at least one inorganic compound, silicon and a mixture thereof, and a water-insoluble organic material, wherein the thickness of said layers of inorganic compound and layers of organic compound are in the range of approximately 100 to 10,000 angstroms, and between approximately 00 angstroms to 5 um, respectively

Description

BARRIER OF MULTIPLE COATS FOR HUMIDITY FOR ELECTROCHEMICAL CELL TESTER BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a moisture barrier, multi-layered, transparent to light. More particularly, this invention relates to a thin-film, light-transparent multilayer composite comprising a plurality of alternating layers of an inorganic material and an organic material useful as a moisture barrier, for a sensitive tester. to the humidity on the cell, a process for the elaboration of said barrier and also refers to an electrochemical cell that has a tester sensitive to humanity on the cell, and the barrier.

Background of the Invention The use of testers of cell condition, such as thermochromic voltage testers, to visually indicate the condition of REF: 25230 An electrochemical cell, commonly referred to as a battery or battery, has become very popular and provides an added value advantage to the battery manufacturer and the consumer. These testers are used with primary electrochemical cells, although these can also be used by consumers to test the condition of a secondary or rechargeable electrochemical cell, if desired. The most popular tester currently in use is a thermochromic material in contact with an electrical resistance element which forms an integral part of a container or battery pack in which the batteries are alkaline primary cells. The user places the terminals of the cell between the contacts of the tester and tightens the contact ends of the tester to make electrical contact with the terminals of the cell, which are the ends of the cell. The resistance element of the tester is heated in proportion to the voltage of the cell and the thermochromic material provides a quantitative indication of the condition of the cell over a range indicating "good" or "replace". This type of tester is described, for example, in U.S. Patent No. 4,723,656. An integral thermochromic package tester, which can also be removed from the package or packaging, is described in US Patent No. 5,188,231. More recently, testers have been developed on the cell in which the condition indicator of the cell is an integral part of the cell label. These testers on the cell include the thermochromic type and a new one, the type of electrochemical tester. An example of a thermochromic type of a tester on cell is described in European Patent Publication No. 0,523,901 Al, the disclosure of which is incorporated by reference herein. Contrary to the thermochromic type that uses a resistance element to produce heat, and which may therefore not be permanently coupled to the cell terminals without continuously discharging it, the new electrochemical type does not draw current from the cell and may so be permanently coupled to the terminals of the cell without downloading to the cells. This new type of tester is described in U.S. Patent Nos. 5,350,905 and 5,339,024 the descriptions of which are incorporated by reference herein. As described in U.S. Patent No. 5,355,089, some electrochemical types of condition testers, on cell, employ hygroscopic or otherwise moisture sensitive electrolytic compositions, and are necessary means to prevent moisture from reaching the electrolyte which will deteriorate the effectiveness of the tester. This patent describes a number of solutions to this problem, the best of which is mica, however, although mica is relatively inexpensive, it is not available in long ribbons or in other forms that allow it to be rolled into a mica roll. which is necessary for commercial, economically viable production methods.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates broadly to a multi-layered, light-transparent composite, which is useful as a moisture barrier and which comprises a plurality of alternating layers of a solid inorganic material and a solid organic material, and the which is formed by the deposition or formation of said layers on a substrate. More particularly, the invention relates to a thin film, the multilayer composite comprising alternating inorganic and organic layers deposited or formed on an appropriate substrate, and which is useful as a moisture barrier. In one embodiment the compound of the invention is used as a moisture barrier for a tester on cell, sensitive to moisture, which visually indicates the condition of an electrochemical cell. In yet another embodiment, the invention relates to a process for making the multilayer composite. In other embodiments, the invention relates to a composite moisture barrier of multiple layers of the invention, in combination with a tester on a cell and an electrochemical cell having a tester on humidity-sensitive cells protected from moisture by said compound. In the further embodiments, the compound of the invention is used as a packaging or packing material for materials and articles sensitive to moisture. In this way, the light-transparent properties of the multi-layer, thin film composite material, when used as a moisture barrier for a tester over a cell, makes it possible for someone to observe the condition of the cell as shown by the color, printed signs or other visual means used by the tester to indicate the condition of the cell. In an embodiment in which the compound of the invention is used as a moisture barrier for an on-cell tester for an electrochemical cell, the substrate is a flexible polymer and the composite is a thin film composite, transparent to the light, flexible, in which the thickness of each of the layers is no more than five microns and preferably no greater than one micron. By cell tester is meant a tester which visually indicates the condition of the cell and is permanently coupled to the cell either by means of the cell tag or other means, although the invention is not limited to this mode. One type of humidity-sensitive cell tester for which the moisture barrier composite of the invention is useful, is a tester which includes at least one hygroscopic material which, if it absorbs water vapor, deteriorates or deteriorates. destroys the effectiveness of the tester. Another type is a tester which includes at least one component that requires the presence of a predetermined amount of water to function, and which therefore needs a moisture barrier to maintain that water level in the tester. The inorganic material and the organic material are solid and, with the exception of silicon, are compounds and not elements. The organic material is generally a polymer and, with the exception of silicon, the inorganic material is non-metallic, and is a compound such as nitride, oxide, etc. Silicon is not generally considered a metal due to its electrically semiconducting nature. The inorganic and organic materials are insoluble in water and have as low a vapor permeation rate as possible for moisture barrier applications, and in these applications the organic material preferably comprises a hydrophobic polymer. The process for making the multilayer composite comprises the deposition or the formation of a first layer on a substrate, followed by the deposition of a second layer on the first layer, wherein the first and second layers are different materials with one being the organic material and the other inorganic material, and repeating the deposition of alternating layers until the number of layers required to produce a multilayer composite having the desired properties has been applied. Thus, the compound of the invention is distinguished from laminates in which several pre-existing layers are adhesively or otherwise bonded to one another, and because the alternating layers of composite material of the invention are formed in themselves over the substrate, or other layers of the composite material by deposition or coating processes. The organic material is applied as a liquid and then cured or dried, or it is applied as a monomer, prepolymer or polymer by physical processes of vapor deposition (PVD), crackling, physical vapor deposition increased by plasma, chemical vapor deposition and any other appropriate means. The inorganic layers are also applied by processes known to those skilled in the art and include various processes (PVD), crackling, physical vapor deposition enhanced by plasma, chemical vapor deposition (CVD) and other appropriate processes depending on the materials used, as will be described later in this.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates a fourteen layer moisture barrier according to the invention.

Figure 2 (a) schematically illustrates a cross-section of a tester on cell, on a cell with a moisture barrier of the invention, and Figure 2 (b) illustrates schematically, in partial broken lines, a side view of a cell having a tester on cell and a moisture barrier, of the invention.

DETAILED DESCRIPTION Figure 1 schematically illustrates a thin-film, multi-layer moisture barrier 10 of the invention, comprising a plastic or polymeric substrate 12 on which a multilayer structure comprising seven layers of inorganic material such as layers 14, 18, 22, 26, 30, 34 and 38, and seven layers of organic material such as layers 16, 20, 24, 28, 32, 35 and 40. The thickness of each of the organic layers is in general within the range of about 100 angstroms to about 5 microns, and preferably within the range of about 1000 angstroms to about 1 micron. The thickness of the inorganic layers is generally in the range of about 100 angstroms to 10,000 angstroms, preferably in the range of about 200 angstroms to 5,000 angstroms, and even more preferably from about 300 to 3,000 angstroms. Thus, except for the use of organic material and the use of a plastic substrate, the construction of the moisture barrier illustrated in Figure 1 with respect to the construction of alternating material and the thickness of the layers, is similar to that of the optical interference coatings, of multiple layers, of thin film used on lamps, on lenses, reflectors and other optical articles. Also, the thickness of each of these layers that is within these ranges is believed to place the composites of the invention in the thin film category. The number of layers and the thickness of the layers will, of course, depend on the intended use of the multi-layer composite material and the materials used for the inorganic layers and the organic layers. In the particular construction illustrated in Figure 1, all the organic layers are of the same thickness and are of the same material, and all the inorganic layers are of the same thickness and of the same material. However, the invention includes multi-layer compounds in which not all inorganic layers are of the same thickness, or of the same material, and also in which not all inorganic layers are of the same thickness or the same material, as may be appreciated by those skilled in the art. Also, although a composite material of fourteen layers (excluding the substrate) is illustrated merely for convenience, the compound of the invention will have more or fewer layers, with the total number of layers (excluding that of the substrate) in the range of 3 to 100 or more, preferably at least 4, and even more preferably at least 6 alternating layers, at the discretion and ability of the practitioner. In addition, in the embodiment illustrated in the figure, all the layers are on one side of the substrate. If desired, the alternating inorganic and organic layers are applied on both sides (upper and lower) of the substrate to form a compound of the invention. In addition, although the multilayer composite of the invention is useful as a moisture barrier, thin film for electrochemical testers on cell, it is also useful as a moisture barrier for moisture sensitive foods, chemicals, pharmaceutical products, electronic products and articles as described above. Those skilled in the art will appreciate that it can also be designed and used for other applications, including optical applications such as transmission and selective reflection of various portions of the electromagnetic spectrum. In yet another embodiment, the substrate 12 is a network having a releasable surface on which the first layer is deposited, so that the multilayer structure can be removed and used without the substrate on which it was formed, or it can be formed on a first substrate, and then transferred to a second substrate. For most applications, a substrate is needed to strengthen the capacity of the multi-layer composite material to be handled and used in manufacturing processes, without breaking. In the embodiment illustrated in Figure 1, the substrate does not have a releasable surface, with the first layer applied to the substrate which is the inorganic layer, and the last applied layer being a layer of organic material. If desired, the first layer deposited on the substrate may be a layer of organic material, and the last layer of the composite material may be a layer of either inorganic or organic material, depending on the intended use. It has been found that if the inorganic material is a relatively brittle material or a material that is prone to cracking, such as glass, metal oxide or metallic nitride, coating it with a layer of organic material protects it from being damaged when it is handled, reduces its tendency to cracking or breaking when bending or flexing, and also protecting the inorganic material from direct contact with corrosive environments. In this case, the outer layers of the composite material are organic material, of which one may be a plastic or polymeric substrate as illustrated in Figure 1. It has also been found, and is substantial for the practice of the invention, that it is important that the layers of inorganic material are separated by organic material, to avoid the propagation of cracks and defects in the inorganic material. That is, it has been found that a crack, small hole or other defect in an inorganic layer deposited by one of the deposition processes referred to below, tends to be carried within the next layer of inorganic material, if the next layer of inorganic material is deposited directly on the first layer of inorganic material, without the intervention of the layer of inorganic material between the two inorganic layers. This phenomenon significantly reduces the usefulness of the composite material as a moisture barrier, since such defects frequently propagate through all inorganic materials if no intervening layer of inorganic material is interposed between the inorganic layers. A similar phenomenon sometimes occurs with respect to organic materials deposited as layers according to the practice of the invention. In this way, the formation of a macroscopic or microscopic orifice, the inclusion of a dust particle, etc. can occur. during the deposition process, and this provides an easy way for the transmission of water vapor. By alternately depositing the layers of inorganic material and layers of organic material, such defects of the layer or film in any particular layer do not tend to propagate within the overlying layer which covers the defect, thereby providing a much better pathway. longer and tortuous so that the water vapor goes through, even to such a degree that the net result is as if such defects do not exist. From a technical point of view, thinner layers and more layers provide more resistance to the transmission of water vapor through the composite material. However, the cost of the moisture barrier increases with each layer that is deposited. As wellIf the layers are too thin, there will be empty spaces or incomplete coverage in the layers, and this will increase the permeability of the composite material. As stated above, the thin film, multilayer composite material of the invention is different from prior art laminates in that the layers of the invention are formed by the alternate deposition of the inorganic and organic materials one over the other. the other by means other than lamination by adhesive or otherwise bonding the preformed ribs or sheets of material, to form a layered structure. Also, it is within the scope of the invention to have one or more organic layers which, themselves are made of two or more layers of different organic materials, such as the use of a coating layer or coating on a layer of inorganic material to achieve better interlayer adhesion, on which a different organic material is deposited, with the composite material of the two different organic materials that form the organic layer. Similarly, two or more layers of inorganic material can be applied to form an inorganic layer in the context of the invention. It is also within the scope of the invention, and forms a mode thereof, that one or more composite materials of the invention (which are not laminated composite materials) can be laminated to one another or to other compounds or materials, or combinations of the same, to form a laminated structure comprising at least one or at least two or more composite materials of the invention.

In addition, although the thin film multilayer composite of the invention does not include the use of metal layers, the composite material of the invention can be laminated with one or more layers of metal, or one or more layers of metal can be deposited on the composite material of the invention, with a further compound of the invention deposited on the metal layer to form a structure comprising alternating composite materials of the invention, and metal layers. Those skilled in the art will appreciate that metal coatings are opaque to light. However, such structures are useful for applications that do not require light transmission properties. Layer deposition processes useful in the practice of the invention include various PVD processes such as electronic deposition or sputtering and evaporation, including sputtering by radio frequency (RF) and magnetron sputtering. Also useful are plasma polymerization, monomer vapor deposition, various CVD, low pressure chemical vapor deposition (LPCVD), and plasma-assisted chemical vapor deposition (PECVD) processes that are known to those skilled in the art. High-speed methods for applying a coating or layer to a substrate on a reel or roll are also known and are described, for example, in U.S. Patent Nos. 4,543,275 and 5,032,461. In general, only one layer is deposited once in a vacuum chamber. Thus, for example, a layer of silica or silicon nitride is deposited on one or both sides of the substrate. Subsequently, the target material in the vacuum chamber is changed to a polymer or the substrate coated with silica is transferred to another chamber in which the target material is the polymer. The polymer is then deposited as a layer on the layer or layers of silica. However, if desired, at least one layer of the inorganic material and at least one layer of polymer are deposited on one or both sides of the substrate inside a vacuum chamber, by use in the chamber, of at least two targets of sizzle or deposition bombardment (in the case of sputtering or bombardment). For example, in a vacuum chamber in which deposition of the layer occurs by magnetron-enhanced crackling, the substrate is an electrode and the target material to be deposited on the substrate is the other electrode, with the plasma in-between electrodes in the case of the deposition of a layer on one side of the substrate. Alternatively, the target material and the plasma are on both sides of the substrate for the deposition of a layer on both sides at the same time, in which case a layer of either inorganic material or organic material is deposited on both sides of the substrate or the substrate. substrate coated with the inorganic layer. In addition, if the substrate is a moving tape or film, then more than one material is deposited in one step of the substrate when sequentially more than one lens is used in the vacuum chamber. Thus, if the substrate is a moving tape or film, as the substrate moves beyond the first objective or group of objectives, a layer of inorganic material is deposited on one or both sides of the substrate. As the substrate coated with inorganic material continues to move toward the second objective or group of targets in the chamber downstream of the first objective or targets, a layer of organic material is deposited on the layer of inorganic material, and so on. In this way, a multiple number of layers is applied to the substrate in one step of the substrate in the vacuum chamber, to form a composite material illustrated in Figure 1, or a composite material having more or less layers than that illustrated in FIG. Figure 1.

As stated above, U.S. Patent Nos. 5,250,905 and 5,339,024 describe cell testers which may contain one or more moisture sensitive components., which therefore requires that a moisture barrier be employed in conjunction with the moisture sensitive tester, to prevent moisture from deteriorating the effectiveness of the tester as described in US Patent No. 5,335,089. One method which has worked with some success is the use of a small sheet of mica placed on the tester above the cell, and sealed by means of a suitable moisture resistant material, such as polyisobutylene, as described in the patent. ? 089 Figures 2 (a) and 2 (b) schematically illustrate a side view of a tester on cell, on a cell with a moisture barrier of the invention, and a top view on partial broken lines, respectively. Thus, Figure 2 illustrates schematically an electrochemical cell 50 having a cell tester 60 of the type described in the '089 patent and which contains at least one hygroscopic component (not shown), with a thin film, the layer barrier multiple against the humidity of the invention, 70, placed on the tester and sealed to the outside of the metal cell container 52 by means of the sealant 62, and with the plastic label 70 wrapped around the cell, and placed on the tester, the seal and the barrier against moisture. Tester 60 is approximately 254 microns (10 mils) thick and is coupled to positive terminals 54 and negative 56 of the cell, by means not shown. As described in the '089 patent, the tester 60 contains, for example, an aprotic organic electrolyte such as 0.5 M lithium trifluoromethanesulfonate in 2.4: 2.4: 5.2 parts by volume mixture of solvent, ethylene carbonate: propylene carbonate: polyvinylidene fluoride, which is very hygroscopic. The sealant material is, for example, a polybutylene elastomer modified with maleic anhydride, available as Vestoplast V3645 from Huís, Inc. in Piscata ay, NJ. The label is a PVC film wrapped around the cell and the moisture barrier / tester / sealer, and then shrunk by heat. As a practical matter, for use as a moisture barrier for an on-cell tester over an electrochemical cell, such as the cell-labeled testers described in the aforementioned patents, the total thickness of the moisture barrier, including the substrate is no greater than about 38.1 microns (1.5 mils) and preferably within about 25 microns or one thousandth of an inch. In the embodiment illustrated in Figure 2, the moisture barrier 10 of the invention comprises a 25 micron (1 mil) thick polyethylene naphthenate film, as the substrate on which fourteen layers have been deposited. alternate inorganic material and organic material as illustrated in Figure 1, to produce a moisture barrier of 33 microns (1.3 mil) and having a moisture vapor transmission rate of less than 0.775 mg of water / cm2 (5 micrograms / square inch) of surface area in a twenty-four hour period, measured according to the procedure described below. The seven inorganic layers are all 500 angstroms thick layers of a water resistant glass having a relatively low melting temperature of about 350 ° C, each layer of which is deposited by bombardment or sputtering. The seven organic layers are each a single-thickness di-paraxylylene polymer of one thickness, each layer being deposited on a glass layer by vapor-phase polymerization of the mono-hexamethylene monomer on each layer of glass subjected to crackling. or bombing. The first layer deposited on the substrate is glass and the last or fourteenth layer is the polymer, as illustrated in Figure 1. In this way, both sides of each glass layer are covered with a layer of organic material, one of which is the mono-elongated di-paraxylylene polymer, and the other of which is the substrate. The water permeation of the multi-layer moisture barrier is measured by placing an anhydrous polyvinylidene fluoride strip of 0.35 mm (0.25 inches) in width and 76.2 microns (3 mils) in thickness, and which contains 70% by weight of sulfolane, together with an aprotic organic electrolyte such as 0.5 M lithium trifluoromethanesulfonate in 2.4: 2.4: 5.2 parts by volume of ethylene carbonate solvent mixture: propylene carbonate: polyvinylidene fluoride, the which is very hygroscopic, on an aluminum film of 12.7 microns (0.5 thousandths of an inch) of thickness, on which a rectangle of 2.54 cm (one inch) in width and 4.32 cm is applied (1.7 inch) in length of the moisture barrier, of the invention, which is sealed to the aluminum sheet by a 63.5 micron (2.5-thousandths of an inch) thick sealant, as generally illustrated in the Figure 2. The seal is a polybutylene elastomer modified with maleic anhydride. This assembly is carried out under anhydrous conditions in a sealed box for handling with gloves. The laminate formed in this way is then maintained at 60 ° C and 100% relative humidity for one week, after which the polyvinylidene fluoride strip containing sulfolane is removed and analyzed for water content by titration by the method by Karl Fischer. This is the test method and test conditions referenced and those used in the following examples. A moisture barrier of the invention will have a moisture vapor transmission rate of less than 15 and preferably less than 5, and even more preferably less than 0.3 mg / cm2 for every 6.45 cm2 (2 micrograms of water per inch2) ) of surface area in a period of twenty-four hours, measured according to this procedure and test conditions. In the manufacture of a thin film, multilayer composite material of the invention, useful as a moisture barrier for a tester on cell, the layers are deposited on a flexible substrate, such as a flexible polymer film in the form of a ribbon, strip or net, or other appropriate substrate material. The substrate need not be flexible, although in the manufacture of the multilayer composite material of the invention for use as a moisture barrier, a flexible substrate is preferred to resist bending during the barrier manufacturing process, and its application to the cell. The first layer deposited on the substrate is generally the inorganic layer, although the organic material may, if it is desired to be applied as the first layer. By way of an illustrative but not limiting example of the process of the invention, a first layer of inorganic material is deposited on the substrate, and a first layer of organic material is deposited on the first layer of inorganic material. A second layer of inorganic material is then deposited on the first layer of organic material. After this, a second layer of organic material is deposited on the second layer of inorganic material. A third layer of inorganic material is then deposited on the second layer of organic material, and a third layer of organic material is deposited on the third layer of inorganic material. This alternating layering is repeated until the desired number of layers has been achieved, as illustrated in Figure 1. Although Figure 1 illustrates a total of fourteen layers or seven pairs of layers, the effective number of layers will depend on the application and the materials used and, in the broadest sense, the multi-layer composite material of the invention can be used for applications other than a moisture barrier, and a number of layers can vary from four to more than one hundred . The inorganic layer is a solid inorganic compound such as an oxide, nitride, carbide, phosphide or phosphate, etc., and mixtures of such compounds of at least one element selected from the group consisting essentially of metal, silicon, boron, arsenic and mixtures. thereof. In one embodiment, the inorganic material is silicon. For example, the inorganic compound will be a nitride, phosphide, phosphate, oxide, carbide, oxyhalide, borate, silicate, tungstate, etc. and mixtures thereof. An illustrative but not limiting example of an embodiment in which the inorganic layer is a mixture of inorganic compounds, is a moisture resistant glass comprising a tin-lead-phosphorus oxyfluoride composition applied by an electronic deposition or crackling process by PVD. Other moisture resistant glass compositions are useful, with illustrative, but not limiting examples including boro-phospho-silicates, silicates, phosphates, arseniates, vanadates, niobaths, tantalates, tungstates, borosilicates, aluminosilicates, calcined glass such as sulfur, selenide, tellurides, etc. In yet another embodiment this is a nitride such as nit, amorphous silicon ruro or any suitable metal nitride, a simple oxide such as SiO, A1203, Nb2? 5, or a compound such as SIxNyOz, or one or more intermetallic compounds, etc. . For use in a moisture barrier for a cell tester according to the invention, the inorganic layer is stable in the presence of moisture and has a degree of flexibility to enable the multilayer composite to flex without cracking or break the inorganic layer, and with this decrease the effectiveness of the composite material as a barrier against moisture. In moisture barrier applications, the inorganic compound is insoluble in water, which means that it will have a dissolution ratio in water of less than 1 X 10"4 g / cm2-minute at 25 ° C, preferably less than 1 X 10"5 g / cm2-minute at 25 ° C and still more preferably 1 X 10-6 g / cm2-minute at 25 ° C. The organic layer is a solid, and more generally a polymeric material. The polymeric material is amorphous or crystalline, elastomeric, crosslinked or non-crosslinked, etc., depending on the use of the composite material and the environment to which it is exposed in use. Examples of suitable organic materials include microcrystalline waxes, condensed aromatics, polyolefins, polyvinyl chloride and copolymers thereof, polyolyllenes, fluoropolymers and copolymers, elastomers, polyimides, polyamides, epoxies, polyesters, polyethers, polycarbonates, halogenated polymers, etc. , as illustrative examples, but not limiting. Halogenated polymers, including fluorinated carbon polymers, are also useful in the practice of the invention. Acrylic polymers are useful in the practice of the invention and particularly acrylic polymers having hydrocarbon chains of at least 6 carbon atoms, such as acrylic polymers formed from a reaction in which the monomer or monomers include hexylmethacrylate and / or hexyl acrylate, etc. Solid organic materials that are not polymeric, which are useful in the practice of the invention include, for example, methyl stearate, stearic acid, and the like. For use in a moisture barrier, the organic material is preferably hydrophobic, stable in a humid environment, and with a permeability to moisture or water vapor, as low as possible. For a moisture barrier application, the organic material layer has a moisture permeability less than 0.787 grams-μm / cm2-24 hours (20 grams-thousandth of an inch / 100 inches2-24 hours), preferably less than 0.394 grams-μm / cm2-24 hours (10 grams-thousandth of an inch / 100 inches2-24 hours), and more preferably less than 0.039 grams-μm / cm2-24 hours (1 gram-thousandth of an inch / 100 inches2-24 hours) ) at 38 ° C (100 ° F) and 90% relative humidity, as measured by the ASTM F 372-78 method which appears in Volume 15.09 of the 1994 Annual Book of the ASTM Standards. The organic layer is deposited by flow coating, by condensation, by reaction of the monomers or prepolymers, by PVD such as sputtering, by CVD, and any of the other general methods referred to above, depending on the properties of the composite material, the nature of the organic layer and the deposition process used, as will be appreciated by those skilled in the art. The invention will also be understood by reference to the following examples, in all of which the moisture barrier is transparent to light.

EXAMPLES Example 1 In this example, a 25.4 μm (1 mil) thick film of polyethylene naphthenate (Kalodex) is the substrate and is coated by sputtering or bombardment in 1.5 millitorr of argon with a moisture resistant glass, to form a layer 500 Angstroms thick glass over the film. The glass has a melting point of about 350 ° C and is prepared by melting, at 500 ° C for 30 minutes, a batch having the composition SnO: SnF2: PbO: P205 in a ratio of 32: 37: 8 :2. 3. After this, the glass layer is coated with a 1 μm thick layer of a mono-di-ethylylene di-polyethylene polymer by heating the solid mono-ary di-paraxylylene dimer (Parylene C from Union Carbide) at a temperature of about 160 °. C to vaporize the dimer, passing the vapors through a heat pipe to break the dimer into monomer at about 600 ° C, and passing the monomer thus formed into a vacuum chamber having a pressure of 20 Torr and a temperature of about 30 ° C in which the monomer is condensed and polymerized in itself on the glass-coated substrate, to form a 1 μm thick layer or coating of the polymer directly on the glass layer. This polymer is a linear, non-crosslinked polymer, mainly hydrocarbon type. This alternating layer deposition process is repeated two or more times to form six alternating layers of glass and polymer (3 glass and 3 polymer) on the substrate, and the thin film, multi-layer moisture barrier, thus formed, it has a water vapor transmission rate of 8.06 μg of water x cm2 surface area (52 μg of water x inch2) in a 24 hour period, as determined by the test method referenced previously in the DETAILED DESCRIPTION part.

Example 2 Example 1 is repeated, but with a total of ten alternating layers (5 glass and 5 polymer) of the glass and polymer deposited on the substrate to form a moisture barrier which has a water vapor transmission rate of 3.72 μg of water per cm2 (24 μg of water per inch2) of surface area over a period of 24 hours as determined by the test method referenced above in the DETAILED DESCRIPTION.

Example 3 Example 1 is repeated again, but with fourteen alternating layers of glass and polymer (7 glass and 7 polymer), to form a moisture barrier as illustrated in Figure 1, which has a transmission ratio of water vapor of 0.73 μg of water per cm2 (4.7 μg of water per inch2) of surface area over a period of 24 hours, as determined by the test method referenced above in the DETAILED DESCRIPTION.

Example 4 In this example a film of 25.4 μm (1 thousandth of an inch) thick polyethylene naphthenate (Kalodex) is the substrate, and is covered by sputtering with radiofrequency magnetron in 1.5 millitorr of argon with silicon dioxide, to form a layer or SiOx coating approximately 500 angstroms thick. The substrate coated with SiOx is then coated by immersion in a solution of vinyl ether monomer (Vectomer, Allied-Signal) in MIBK containing a trivinylmethylsilane adhesion promoter and a UV initiator, Cyracure 6974 (triarylsulfonium salt). The wet coated composite is exposed to ultraviolet radiation for several seconds and cured in an anhydrous polyvinyl ether coating 3 μm thick. This alternating layer deposition procedure is repeated six more times to form 14 alternating layers on the substrate (7 SiOx and 7 polymer) as illustrated in Figure 1, resulting in a transparent moisture barrier of 50.8. microns (2 mils) thick which is tested using the test procedure in Example 1, and has a water vapor transmission rate of 3.25 μg water per cm 2 (21 μg water per inch 2) area surface over a period of 24 hours, as determined by the test method referred to above in the DETAILED DESCRIPTION.

Example 5 In this example a film of 25.4 μm (1 mil) thickness of polyethylene naphthenate (Kalodex) is the substrate, and is covered by magnetron sputtering to RF in 1.5 millitorr of argon with the glass of Example 1, to form a layer of glass 500 angstroms thick on the film. After this, the glass layer is covered by sputtering with a 1 μm thick layer of a polyvinyl ether as described in Example 4 above (Vectomer 40105F, Allied-Signal). This alternate layer deposition process is repeated six more times to form a moisture barrier that has fourteen alternating layers of glass and polyvinyl ether on the substrate (7 glass and 7 polyvinyl ether) as illustrated in Figure 1 , and the moisture barrier has a water vapor transmission rate of 4.34 μg of water per cm2 (28 μg of water per inch2) of surface area over a period of 24 hours, as determined by the test method referenced above in the DETAILED DESCRIPTION.

Ex emp1o In this example a 25.4 μm (1 mil) film of polyethylene naphthenate (Kalodex) is the substrate, and is coated by magnetron sputtering to RF in 1.5 millitorr of argon with the glass of Example 1 to form a layer of 500 angstroms thick on the film. After this, the glass layer is covered by magnetron sputtering to RF with a 1 μm thick layer of a polychlorotrifluoroethylene (Aclar, Allied-Signal). This alternate layer deposition process is repeated six more times to form a moisture barrier that has fourteen alternating layers of glass and polyvinyl ether on the substrate (7 glass and 7 polyvinyl ether) as illustrated in Figure 1 , and the moisture barrier has a water vapor transmission rate of 4.34 μm of water per cm2 (28 μg of water per inch2) of surface area over a period of 24 hours, as determined by the test method referenced above in the DETAILED DESCRIPTION.

Example 7 In this example, 1 25.4 μm (1 thousandth of an inch) thick film of polyethylene naphthenate (Kalodex) is the substrate, and is covered by magnetron sputtering to RF in 1.5 millitorr of argon with silicon nitride to form a layer or amorphous silicon nitride coating approximately 500 angstroms thick. The PTFE is then bombarded by magnetron to RF on the silicon nitride layer to form a PTFE layer 1 μm thick. This process is repeated once again to form a thin film, multi-layered moisture barrier comprising four alternating layers of amorphous silicon nitride and PTFE (2 silicon nitride and 2 PTFE) on the substrate, the which has a water vapor transmission rate of 4.34 μg of water per cm2 (28 μg of water per inch2) of surface area over a period of 24 hours, as determined by the test method referenced above in DETAILED DESCRIPTION.

Example 8 In this example, a 25.4 μm (1 thousandth of an inch) thick film of polyethylene naphthenate (Kalodex) is the substrate, and is covered by sputtering with magnetron to RF in 1.5 millitorr of argon on one side with a coating of 500 Angstroms thick amorphous silicon nitride. After this, the silicon nitride layer is coated with a 1 μm thick layer of a mono-di-ethylylene polymer by heating the solid mono-ary di-paraxylylene dimer (Parylene C from Union Carbide) at a temperature of about 160 ° C to vaporize the dimer, passing the vapors through a heat pipe to break the monomer dimer at about 600 ° C, and passing the monomer thus formed into a vacuum layer having a pressure of 20 Torr. and a temperature of about 30 ° C at which the monomer is condensed and polymerized in itself on the glass-coated substrate, to form a layer or coating of 1 μm thickness of the polymer directly on the glass layer. This polymer is a linear, non-crosslinked polymer, mainly of the hydrocarbon type. This alternate layer deposition process is repeated three more times to form eight alternating layers of silicon nitride and polymer (4 silicon nitride and 4 polymer) on the substrate, and the moisture barrier, multilayer, thin film, formed in this way has a water transmission rate of 8.06 μg of water per cm2 (52 μg of water per inch2) of surface area in a period of 24 hours, as determined by the test method to which it is referenced above in the DETAILED DESCRIPTION.

Comparative Example A In this example, a 25.4 μm (1 thousandth of an inch) thick film of polyethylene naphthenate (Kalodex) is the substrate, and is covered by magnetron sputtering to RF in 1.5 millitorr of argon with silicon dioxide to form a layer or SiOx coating approximately 500 angstroms thick. A layer of PTFE of 1 μm thickness is then deposited by magnetron sputtering to RF on the SiOx. This alternate layer deposition process is repeated four times more to form a moisture barrier, composite material comprising 10 alternating layers of SiOx and PTFE (5 SiOx and 5 PTFE) on the substrate, and the barrier against the moisture has a water vapor transmission rate of 88.37 μm water per cm2 (570 μm water per inch2) of surface area over a period of 24 hours, as determined by the test method referenced above in DETAILED DESCRIPTION.

Comparative Example B In this example, a 25.4 μm (1 thousandth of an inch) thick film of polyethylene naphthenate (Kalodex) is the substrate, and is covered by magnetron sputtering to RF in 1.5 millitorr of argon with silicon dioxide to form a layer or SiOx coating approximately 500 angstroms thick. A layer of crosslinked polyethylene 1 μm thick is then deposited by sputtering onto the SiOx by means of CVD enhanced by plasma, methane. This alternate layer deposition process is repeated four times more to form a thin film, multi-layer moisture barrier comprising 10 (5 SiOx and 5 polyethylene) alternating layers of SiOx and polyethylene on the substrate which it has a water vapor transmission rate of 57.71 μg of water per cm2 (340 μm of water per inch2) of surface area over a period of 24 hours, as determined by the test method referenced above in the DETAILED DESCRIPTION. It is understood that various other embodiments and modifications in the practice of the invention will be apparent, and readily realized by those skilled in the art, without departing from the spirit and scope of the invention described above. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the description described above, but rather it is considered that the claims encompass all patentable novelty features set forth in the present invention, including all features and embodiments that could be treated as equivalents thereof, by those skilled in the art to which the invention pertains.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, property is claimed as contained in the following:

Claims

1. An electrochemical cell having a condition tester of the cell, sensitive to moisture, and a moisture barrier, transparent to light, characterized in that the moisture barrier comprises a composite material on a polymeric substrate, the composite material it comprises alternating layers of a water-insoluble inorganic material selected from the group consisting of at least one inorganic compound, silicon and a mixture thereof, and a water insoluble organic material, wherein the thickness of said layers of inorganic compound and the organic compound layers are in the range of approximately 100 to 10,000 angstroms, and between approximately 100 angstroms to 5 μm, respectively.

2. A multi-layered, light-transparent composite material comprising alternate layers of a water-insoluble inorganic material selected from the group consisting of at least one inorganic compound, silicon and a mixture thereof, and a water-insoluble organic material , wherein the thickness of said layers of the inorganic compound and the layers of the organic compound are in the range between about 100 to 10,000 angstroms and between about 100 angstroms to 5 μm, respectively.

3. A process for making a thin film, multilayer, non-laminated transparent film composite comprising alternate layers of a water-insoluble inorganic material selected from the group consisting of at least one inorganic compound, silicon and a mixture thereof, and a water-insoluble organic material, wherein the thickness of the layers of the inorganic compound and the layers of the organic compound are in the range between about 100 to 10,000 angstroms and between about 100 angstroms to 5 microns, respectively , characterized the process because it comprises the deposition of a first layer of inorganic material on a substrate, and then the deposit of a first layer of solid organic material on the first layer of inorganic material, followed by the deposition of a second layer of inorganic material solid on the first layer of organic material, and then the deposition of a second layer organic material on the second layer of inorganic material.

4. The process according to claim 3, characterized in that the deposition of alternating layers is repeated until the desired number of layers is achieved.