Electrical shielding article

Abstract

An electrically shielded article includes a flexible and / or elongatable substrate and a conductive ink applied to at least a portion of the substrate. The conductive ink includes a resin and a conductive material. When the conductive ink is applied to the substrate, the conductive material in the conductive ink is present on the substrate in an amount of at least 5 g / m 2 . The electrically shielded article exhibits a signal loss of at least 5 dBm up to 4 mm according to the NFC detune test. Also disclosed is a method of making an electrically shielded article and an identification device including the electrically shielded article.

Description

[0001] This application is a divisional application of application number 201980063423.9, filed on September 25, 2019, entitled "Electrically Shielded Article".

[0002] Cross-references to related applications

[0003] This application claims priority to U.S. Patent Application Serial No. 16 / 576,872, filed September 20, 2019; U.S. Provisional Patent Application Serial No. 62 / 856,306, filed June 3, 2019; U.S. Provisional Patent Application Serial No. 62 / 829,403, filed April 4, 2019; U.S. Provisional Patent Application Serial No. 62 / 827,560, filed April 1, 2019; and U.S. Provisional Patent Application Serial No. 62 / 738,089, filed September 28, 2018, each of which is incorporated herein by reference in its entirety. Technical Field

[0004] This invention relates to an electrically shielded product and a method for preparing it. Background Technology

[0005] Radio frequency (RF) communication enables data to be transmitted from a transmitter, such as an RF-driven chip, to a receiver. Articles and devices in various fields employ RF communication to transmit data by using RF-driven chips embedded within the article or device itself, allowing a specific receiver to receive data stored on it.

[0006] As an example, passports (and other identification devices) typically include radio frequency (RF) driven chips containing data associated with the user who issued the passport. While this allows for more efficient user verification and leads to more efficient travel, some data stored on the RF driven chip may be sensitive or confidential personal information. However, an identity thief with appropriate electronic equipment (such as an RF receiver) could potentially read from or write to the RF driven chip in a user's passport, thus compromising sensitive or confidential personal information.

[0007] Similar concerns exist for data transmitted in other wavelengths of the electromagnetic spectrum, such as in the microwave range and long-range radio wave range. Summary of the Invention

[0008] This invention relates to an electrically shielded article comprising: a flexible and / or elongated substrate; and a conductive ink applied to at least a portion of the substrate, the conductive ink comprising a resin and a conductive material. When the conductive ink is applied to the substrate, the conductive material in the conductive ink has a conductivity of at least 5 g / m³. 2The amount of [something] is present on the substrate. The electrically shielded article exhibits a signal loss of at least 5 dBm at a maximum of 4 mm according to NFC detuning tests.

[0009] The present invention also relates to a method for preparing an electrically shielded article, comprising applying a conductive ink to a flexible and / or elongated substrate. The conductive ink comprises a resin and a conductive material. When the conductive ink is applied to the substrate, the conductive material in the conductive ink has a conductivity of at least 5 g / m³. 2 The amount of [something] is present on the substrate. This electrically shielded article provides a signal loss of at least 5 dBm in up to 4 mm, according to NFC detuning tests.

[0010] This invention further includes the subject matter of the following entries:

[0011] Item 1: An electrically shielded article comprising: a flexible and / or elongated substrate; and a conductive ink applied to at least a portion of the substrate, the conductive ink comprising a resin and a conductive material, wherein when the conductive ink is applied to the substrate, the conductive material in the conductive ink is at a concentration of at least 5 g / m³. 2 The amount of [something] present on the substrate, wherein the electrically shielded article exhibits a signal loss of at least 5 dBm in up to 4 mm according to the NFC detuning test.

[0012] Item 2: The article of electrical shielding as described in Item 1, wherein when the conductive ink is applied to the substrate to form the article of electrical shielding, the conductive material from the conductive ink is at a concentration of 5 g / m 2 Up to 500g / m 2 The amount of it exists on the surface of the substrate.

[0013] Item 3: The article of electrical shielding as described in Item 1 or 2, wherein the conductive ink is prepared from a mixture comprising the resin, the conductive material and the solvent.

[0014] Item 4: The article of electrical shielding described in Item 3, wherein the solvent comprises at least one of an aromatic compound, a ketone, an ester, and an alcohol.

[0015] Item 5: The article of electrical shielding described in Item 3 or 4, wherein the solvent does not contain amine-containing compounds.

[0016] Item 6: An article of electrical shielding as described in any one of items 1-5, wherein the ratio of the conductive material to the resin in the conductive ink is from 0.25:1 to 6:1.

[0017] Item 7: An article of electrical shielding as described in any one of items 1-6, wherein the ratio of the conductive material to the resin in the conductive ink is from 1.5:1 to 2.5:1.

[0018] Item 8: An article of electrical shielding as described in any one of items 1-7, wherein the resin comprises at least one of a rubber-containing resin, a vinyl chloride-containing resin, and a polyester.

[0019] Item 9: An article of electrical shielding as described in any one of items 1-8, wherein the resin comprises a styrene-ethylene-butene-styrene block copolymer.

[0020] Item 10: An article of electrical shielding as described in any one of items 1-8, wherein the resin comprises a vinyl chloride / acrylate copolymer.

[0021] Item 11: An article of electrical shielding as described in any one of items 1-10, wherein the resin comprises at least one of polystyrene, acrylics, polyurethanes, polyvinyl polymers, natural and / or synthetic rubbers and copolymers thereof.

[0022] Item 12: Article of electrical shielding as described in any one of items 1-11, wherein the conductive material comprises at least one of silver, gold, nickel, aluminum, copper, iron-containing materials, alloys and carbon-based materials.

[0023] Item 13: An article of electrical shielding as described in any one of items 1-12, wherein the substrate comprises at least one of silicone, polyurethane and polyolefin.

[0024] Item 14: Article of electrical shielding as described in any one of items 1-13, wherein the substrate is capable of elongation of at least 50%.

[0025] Item 15: An article of electrical shielding as described in any one of items 1-14, wherein the substrate comprises pores.

[0026] Item 16: The article of electrical shielding as described in Item 15, wherein the substrate comprises filler.

[0027] Item 17: Article of electrical shielding as described in Item 16, wherein the filler comprises a siliceous material.

[0028] Item 18: An article of electrical shielding as described in any one of items 1-17, wherein the conductive ink is applied to the substrate by at least one of the following methods: screen printing, spraying, stencil coating, gravure printing, flexographic printing, inkjet printing, digital printing, and 3D printing.

[0029] Item 19: An article of electrical shielding as described in any one of items 1-18, wherein the conductive ink is applied to the substrate in a patterned manner.

[0030] Item 20: An article of electrical shielding as described in any one of items 1-19, wherein the conductive ink is applied to the substrate as a continuous coating over a region of the substrate.

[0031] Item 21: An article of electrical shielding as described in any one of items 1-20, wherein, when a force is applied to the article of electrical shielding, the article of electrical shielding is stretchable from a first orientation having a first signal loss to a second orientation having a second signal loss.

[0032] Item 22: The article of electrical shielding as described in Item 21, wherein when the force is removed, the article of electrical shielding relaxes to substantially the first orientation and substantially the first signal loss.

[0033] Item 23: Article of electrical shielding as described in any one of items 1-22, wherein the D50 particle size of the conductive material is from 0.5 μm to 100 μm.

[0034] Item 24: A method for preparing an electrically shielded article, comprising: applying a conductive ink to a flexible and / or elongated substrate, wherein the conductive ink comprises a resin and a conductive material, wherein when the conductive ink is applied to the substrate, the conductive material in the conductive ink is at least 5 g / m³. 2 The amount of [something] present on the substrate, wherein the electrically shielded article provides a signal loss of at least 5 dBm in up to 4 mm according to the NFC detuning test.

[0035] Item 25: The method described in Item 24, wherein the conductive ink is applied to the substrate by at least one of the following application methods: screen printing, spraying, stencil coating, gravure printing, flexographic printing, inkjet printing, digital printing, and 3D printing.

[0036] Item 26: An identification device comprising an article of electrical shielding as described in any one of items 1-23.

[0037] Item 27: The identification device described in Item 26, wherein the identification device contains machine-readable travel documents.

[0038] Item 28: The identification device described in Item 26 or 27, comprising: a first page containing the electrically shielded article; and a second page containing the antenna. Attached Figure Description

[0039] Figure 1A An electrically shielded article is shown, wherein conductive ink is applied to a substrate in a grid pattern;

[0040] Figure 1B An electrically shielded article is shown, wherein conductive ink is applied to a substrate by flood coating;

[0041] Figure 2 This shows an electrically shielded product;

[0042] Figure 3An identification device (e.g., a passport) is shown, which includes an electrically shielded article;

[0043] Figure 4 The signal loss graphs of samples 1, 5 and 6 of the embodiments at various frequencies are shown;

[0044] Figure 5 The detuning plots of sample 4 at several gap distances are shown;

[0045] Figure 6A and 6B The resonant frequency diagrams showing signal loss and detuning at different gap distances for samples 2, 6, and the control copper sheets are displayed.

[0046] Figure 7 The signal loss plot of sample 4 as a function of % elongation is shown;

[0047] Figure 8A and 8B The graph shows the resistance as a function of % elongation, measured separately in the transverse and longitudinal directions;

[0048] Figure 9 The image shows a box sealed with electrical shielding tape (an example of an electrically shielded article);

[0049] Figure 10 This shows a space with electrically shielded wallpaper on the walls and / or ceiling (an example of an electrically shielded artifact), forming an electrically shielded room;

[0050] Figure 11 A wallet for carrying electronic payment cards is shown, the wallet including electrically shielded components; and

[0051] Figure 12 It shows a roll of electrical shielding products, such as electrical shielding tape, electrical shielding paper, etc. Detailed Implementation

[0052] For the purposes of the detailed description below, it should be understood that the invention may take various alternative variations and sequences of steps unless expressly specified otherwise. Furthermore, except in any operational example or as otherwise indicated, all figures used to indicate quantities of ingredients, for example, in the specification and claims, should in all cases be understood to be modified by the term "about". Therefore, unless otherwise indicated, the numerical parameters listed in the following specification and appended claims are approximations that can vary with the desired properties obtained according to the invention. At the very least, and without attempt to limit the application of the doctrine of equivalence to the scope of the claims, each numerical parameter should be interpreted at least according to the number of significant figures reported and by applying common rounding techniques.

[0053] Although the numerical ranges and parameters illustrating the broad scope of the invention are approximate, the values ​​listed in the specific embodiments are reported as precisely as possible. However, any numerical value inherently contains some error that must be introduced by the standard deviation present in their respective test measurements.

[0054] Additionally, it should be understood that any numerical range listed herein is intended to include all subranges contained therein. For example, the range “1 to 10” is intended to include all subranges between the listed minimum value of 1 and the listed maximum value of 10 (and including end values), i.e., the minimum value is equal to or greater than 1 and the maximum value is equal to or less than 10.

[0055] As used in this article, the articles “a,” “one,” and “the” include multiple referents unless explicitly and meaninglessly limited to a single referent.

[0056] As used herein, the transitional term “comprising” (and other equivalent terms such as “containing” and “including”) is “open-ended” and openly encompasses substances not explicitly identified. While described as “comprising,” the terms “essentially composed of” and “composed of” are also within the scope of this invention.

[0057] As used herein, the term "electrically shielded article" refers to an article which provides electrical shielding for itself or some other article by means of the function of the article or components thereof.

[0058] This disclosure relates to an electrically shielded article comprising: a flexible and / or elongated substrate; and a conductive ink applied to the substrate, the conductive ink comprising a resin and a conductive material, wherein when the conductive ink is applied to the substrate, the conductive material in the conductive ink has a conductivity of at least 5 g / m³. 2 The amount of [something] present on the substrate, wherein the electrically shielded article exhibits a signal loss of at least 5 dBm in up to 4 mm according to the NFC detuning test.

[0059] The article of this electrical shielding can provide electrical shielding frequencies falling within at least one of the following ranges of the electromagnetic spectrum: ultraviolet, visible light, infrared, microwave, and radio waves (including long radio waves). The article of this electrical shielding can provide electrical shielding in the microwave and / or radio wave (including long radio waves) range. These various ranges are defined as follows:

[0060]

[0061]

[0062] The substrate may be flexible or elongated. The substrate may be elongated by at least 10%, such as at least 50%, or at least 100%, compared to its original length and / or width. The substrate may be elongated by 10% to 1000%, such as 50% to 1000%, or 100% to 1000%, compared to its original length and / or width. The substrate may include at least one of silicone, polyurethane, and polyolefin. The substrate may include... The membrane (available from PPG Industries, Inc. (Pittsburgh, Pennsylvania)). The substrate may include... Diaphragm (available from Entek (Lebanon, Oregon)) or Diaphragm (available from Polypore International, LP (Charlotte, North Carolina)).

[0063] The substrate may contain pores. The substrate may include microporous materials.

[0064] As used herein, “microporous material” or “microporous sheet” refers to a material having an interconnected network of pores, wherein, in the absence of treatment, coating, printing ink, impregnation agent and pre-bonding, the volume-average diameter of the pores ranges from 0.001 to 1.0 micrometers and accounts for at least 5% of the volume of the microporous material, as described below.

[0065] The polyolefin polymer matrix may contain any number of known polyolefin materials known in the art. In some cases, different polymers derived from at least one olefin unsaturated monomer may be used in combination with the polyolefin polymer. Suitable examples of such polyolefin polymers may include, but are not limited to, polymers derived from ethylene, propylene, and / or butene, such as polyethylene, polypropylene, and polybutene. High-density and / or ultra-high molecular weight polyolefins, such as high-density polyethylene, are also suitable. The polyolefin matrix may also contain copolymers, for example, copolymers of ethylene and butene or copolymers of ethylene and propylene.

[0066] Unrestricted examples of ultra-high molecular weight (UHMW) polyolefins may include substantially linear UHMW polyethylene (PE) or polypropylene (PP). Because UHMW polyolefins are not thermosetting polymers with an infinite molecular weight, they are technically classified as thermoplastic materials.

[0067] Ultra-high molecular weight polyethylene can comprise substantially linear ultra-high molecular weight isotactic polyethylene. Typically, such polymers have an isotacticity of at least 95%, for example, at least 98%.

[0068] While there is no particular upper limit on the intrinsic viscosity of UHMW polyethylene, in a non-limiting example, the intrinsic viscosity may range from 18 to 39 dL / g, for example, 18 to 32 dL / g. Similarly, while there is no particular upper limit on the intrinsic viscosity of UHMW polypropylene, in a non-limiting example, the intrinsic viscosity may range from 6 to 18 dL / g, for example, 7 to 16 dL / g.

[0069] For the purposes of this invention, the intrinsic viscosity was determined by extrapolating the reduced viscosity or intrinsic viscosity of several dilute solutions of the UHMW polyolefin to zero concentration, wherein the solvent was freshly distilled decahydronaphthalene, to which 0.2% by weight of 3,5-di-tert-butyl-4-hydroxycinnamic acid, neopentanetetramethyl ester [CAS Registry No. 6683-19-8] was added. The reduced viscosity or intrinsic viscosity of the UHMW polyolefin was determined according to the general procedure of ASTM D 4020-81 (except for the use of several dilute solutions of different concentrations) using a Ubbelohde No. 1 viscometer, obtained from a relative viscosity at 135°C.

[0070] The nominal molecular weight of UHMW polyethylene is empirically related to the intrinsic viscosity of the polymer based on the following equation:

[0071]

[0072] Where M is the nominal molecular weight. This is the intrinsic viscosity of UHMW polyethylene expressed in deciliters per gram. Similarly, the nominal molecular weight of UHMW polypropylene is empirically related to the intrinsic viscosity of this polymer according to the following equation:

[0073]

[0074] Where M is the nominal molecular weight. The intrinsic viscosity of UHMW polypropylene is expressed in deciliters per gram (dL / g).

[0075] A mixture of substantially linear ultra-high molecular weight polyethylene (UHMW) and low molecular weight polyethylene (LMW) can be used. The UHMW polyethylene may have an intrinsic viscosity of at least 10 dL / g, while the LMW polyethylene has a melt index of less than 50 g / 10 min under ASTM D 1238-86 condition E, for example less than 25 g / 10 min, or less than 15 g / 10 min, and a melt index of at least 0.1 g / 10 min under ASTM D 1238-86 condition F, for example at least 0.5 g / 10 min, or at least 1.0 g / 10 min. The amount of UHMW polyethylene used in this example (in weight percent) is described in column 1, lines 52 through 2, lines 18 of U.S. Patent No. 5,196,262, the disclosure of which is incorporated herein by reference. More specifically, the weight percent of UHMW polyethylene used is described in relation to Figure 6 of U.S. Patent No. 5,196,262; i.e., referring to polygons ABCDEF, GHCI, or JHCK in Figure 6, which is incorporated herein by reference.

[0076] Low molecular weight polyethylene (LMWPE) has a lower nominal molecular weight than UHMW polyethylene. LMWPE is a thermoplastic material and many different types are known. One classification method is by density expressed in grams per cubic centimeter and rounded to the nearest thousandth, according to ASTM D 1248-84 (re-approved in 1989). Non-limiting examples of density are shown in the table below.

[0077] <![CDATA[ type ]]> <![CDATA[ abbreviation ]]> <![CDATA[ Density, g / cm³ 3 ]]> Low density PE LDPE 0.910-0.925 Medium density PE MDPE 0.926-0.940 High-density PE HDPE 0.941-0.965

[0078] Any or all of the polyethylenes listed in the table above can be used as LMWPE in the matrix of microporous materials. HDPE can be used because it can be more linear than MDPE or LDPE. Methods for manufacturing various LMWPEs are well-known and documented. These include the high-pressure process, the Phillips Petroleum process, the Standard Oil (Indiana) process, and the Ziegler process. For LMWPE, ASTM D 1238-86 Condition E (i.e., 190°C and 2.16 kg load) has a melt index of less than 50 g / 10 min. Typically, the melt index for Condition E is less than 25 g / 10 min. The melt index for Condition E can be less than 15 g / 10 min. For LMWPE, ASTM D1238-86 Condition F (i.e., 190°C and 21.6 kg load) has a melt index of at least 0.1 g / 10 min. Under many conditions, the melt index for Condition F is at least 0.5 g / 10 min, such as at least 1.0 g / 10 min.

[0079] UHMWPE and LMWPE may together constitute at least 65% by weight, for example, at least 85% by weight, of the polyolefin polymer of the microporous material. Furthermore, UHMWPE and LMWPE together may together constitute essentially 100% by weight of the polyolefin polymer of the microporous material.

[0080] The polyolefin polymer matrix may contain polyolefins, including ultra-high molecular weight polyethylene, ultra-high molecular weight polypropylene, high-density polyethylene, high-density polypropylene, or mixtures thereof.

[0081] Other thermoplastic organic polymers may also be present in the matrix of the microporous material, provided that their presence does not adversely affect the properties of the microporous material matrix. The amount of other thermoplastic polymers that may be present depends on the properties of the polymer. Non-limiting examples of thermoplastic organic polymers that may optionally be present in the matrix of the microporous material include low-density polyethylene, high-density polyethylene, poly(tetrafluoroethylene), polypropylene, copolymers of ethylene and propylene, copolymers of ethylene and acrylic acid, and copolymers of ethylene and methacrylic acid. If desired, all or part of the carboxyl groups of carboxyl-containing copolymers may be neutralized by sodium, zinc, etc. Typically, the microporous material contains at least 40% by weight of UHMW polyolefin, based on the weight of the matrix. The aforementioned other thermoplastic organic polymers may be substantially absent from the matrix of the microporous material.

[0082] Microporous materials may further include finely pulverized, granular, substantially water-insoluble inorganic fillers distributed throughout the matrix.

[0083] Inorganic fillers may include any number of inorganic fillers known in the art. The fillers should be finely pulverized and substantially insoluble in water to allow for uniform distribution throughout the polyolefin polymer matrix during the fabrication of the microporous material. Typically, inorganic fillers are selected from silica, alumina, calcium oxide, zinc oxide, magnesium oxide, titanium oxide, zirconium oxide, and mixtures thereof.

[0084] The finely pulverized, substantially water-insoluble filler may be in the form of ultimate particles, aggregates of ultimate particles, or a combination of both. At least 90% by weight of the filler used to prepare this microporous material has a total particle size ranging from 5 to 40 micrometers, as measured using a Beckman Coulton LS230 laser diffractometer, capable of measuring particle sizes down to 0.04 micrometers. Typically, at least 90% by weight of the filler has a total particle size ranging from 10 to 30 micrometers. The particle size of the filler aggregates can be reduced during the processing of the components used to prepare the microporous material. Therefore, the total particle size distribution in the microporous material can be smaller than that in the raw filler itself.

[0085] As mentioned earlier, the filler particles are substantially insoluble in water and also substantially insoluble in any organic processing liquid used to prepare the microporous material. This can help the filler be retained in the microporous material.

[0086] In addition to the filler, other finely ground, granular, substantially water-insoluble materials may optionally be used. Non-limiting examples of such optional materials may include carbon black, charcoal, graphite, iron oxide, copper oxide, antimony oxide, molybdenum disulfide, zinc sulfide, barium sulfate, strontium sulfate, calcium carbonate, and magnesium carbonate. The filler may be silica and / or any of the aforementioned optional filler materials.

[0087] The filler typically has a high surface area to allow it to carry a large amount of processing plasticizers used to form microporous materials. High surface area fillers are materials with very small particle sizes, high porosity, or both. The surface area of ​​the filler particles can range from 20 to 900 m² / g, for example 25 to 850 m² / g, determined according to ASTM C 819-77 by the Brunauer, Emmett, Teller (BET) method, using nitrogen as the adsorbent, with the variation being that the system and sample are degassed at 130°C for one hour. Before adsorbing nitrogen, the filler sample is dried by heating to 160°C for one hour in flowing nitrogen (PS).

[0088] Inorganic fillers may include siliceous materials, such as silica, such as precipitated silica, silica gel or fumed silica.

[0089] Silica gels are typically produced commercially by acidifying an aqueous solution of a soluble metal silicate, such as sodium silicate, at a low pH. The acid used is usually a strong inorganic acid, such as sulfuric acid or hydrochloric acid, but carbon dioxide can also be used. Because there is essentially no difference in density between the gel phase and the surrounding liquid phase, the gel phase does not precipitate, despite its low viscosity. Thus, silica gels can be described as a non-precipitating, coherent, rigid, three-dimensional network of continuous particles of colloidal amorphous silica. The finer details range from large solid blocks to submicron particles, and the hydration levels range from almost anhydrous silica to soft gel-like blocks containing approximately 100 parts by weight of water per part of silica.

[0090] Precipitated silica is typically produced commercially by combining an aqueous solution of a soluble metal silicate or a common alkali metal silicate, such as sodium silicate, with an acid, thereby causing colloidal silica particles to grow in a weakly alkaline solution and coagulate through the alkali metal ions of the resulting soluble alkali metal salt. A variety of acids can be used, including but not limited to inorganic acids. Non-limiting examples of acids that can be used include hydrochloric acid and sulfuric acid, but carbon dioxide can also be used to produce precipitated silica. In the absence of a coagulant, silica will not precipitate from solution at any pH. The coagulant used to achieve silica precipitation can be a soluble alkali metal salt produced during the formation of colloidal silica particles or can be an added electrolyte, such as a soluble inorganic or organic salt, or a combination of both.

[0091] Precipitated silica can be described as precipitated aggregates of colloidal amorphous silica particles that do not exist as macroscopic gels at any point during the preparation process. The size and hydration degree of the aggregates can vary widely. Precipitated silica powder differs from pulverized silica gel in that it typically possesses a more open structure, i.e., a higher specific pore volume. However, the specific surface area of ​​precipitated silica using nitrogen as an adsorbent via the Brunauer, Emmet, Teller (BET) method is generally lower than that of silica gel.

[0092] Many different precipitated silicas can be used as fillers for the preparation of microporous materials. Precipitated silica is a well-known commercial material, and its preparation methods are described in detail in numerous U.S. patents, including U.S. Patent Nos. 2,940,830, 2,940,830, and 4,681,750. The average fundamental particle size of the precipitated silica used (regardless of whether the fundamental particles are agglomerated) is typically less than 0.1 micrometers, for example less than 0.05 micrometers or less than 0.03 micrometers, measured by transmission electron microscopy. Non-limiting examples of suitable precipitated silica include PPG Industries, Inc. (Pittsburgh, Pennsylvania) and... Those products sold under the product name.

[0093] Inorganic filler particles can comprise 10 to 90% by weight of the microporous material. For example, such filler particles can comprise 25 to 90% by weight, such as 30% to 90% by weight, 40% to 90% by weight, 50% to 90% by weight, or even 60% to 90% by weight. The filler is typically present in microporous materials in amounts ranging from 50% to 85% by weight. Generally, the weight ratio of filler to polyolefin in microporous materials ranges from 0.5:1 to 10:1, for example, 1.7:1 to 3.5:1. The weight ratio of filler to polyolefin in microporous materials can be greater than 4:1.

[0094] Microporous materials can include a network of interconnected pores throughout the microporous material.

[0095] In the untreated, uncoated, or impregnated form, these pores can constitute at least 5% by volume of the microporous material, for example, 5 to 95% by volume, 15 to 95% by volume, 20 to 95% by volume, 25 to 95% by volume, or 35 to 70% by volume. Typically, the pores constitute at least 35% by volume or even at least 45% by volume of the microporous material.

[0096] As used in this paper, the porosity (also known as vacancy volume) of microporous materials, expressed as volume % (%), is determined according to the following equation:

[0097] Porosity = 100[1 - d1 / d2]

[0098] Where d1 is the sample density, which is determined by the sample weight and the sample volume as determined by the sample size measurement; d2 is the density of the solid portion of the sample, which is determined by the sample weight and the volume of the solid portion of the sample. The volume of the solid portion of the sample was determined using a Quantachrome stereopycnometer (Quantachrome Instruments (Boynton Beach, FL)) according to the accompanying instruction manual.

[0099] Porosity can also be measured using a Gurley Densitometer Model 4340 manufactured by GPI Gurley Precision Instruments, Troy, New York. The reported porosity value is a measure of the rate at which air flows through the sample or its resistance to the flow of air through the sample. The unit of measurement for this method is the “Gurley second” and is expressed in seconds as the time, expressed as seconds, to pass 100 cc of air through a 1 square inch area using a pressure differential of 4.88 inches of water. Lower values ​​correspond to lower airflow resistance (allowing more air to pass freely). For the purposes of this invention, measurements were performed using the procedures outlined in the manual for the Model 4340 automatic densitometer.

[0100] The volume-average diameter of the pores in microporous materials can be determined using the mercury porosity method with an Autopore III porosimeter (Micromeritics (Norcross, GA)) according to the accompanying instruction manual. The volume-average pore radius for a single scan is automatically determined by the porosimeter. When operating the porosimeter, scans are performed in the high-pressure range (138 kPa to 227 MPa). If approximately 2% or less of the total intrusion volume occurs at the lower end of this high-pressure range (138 to 250 kPa), the volume-average pore diameter is taken as twice the volume-average pore radius determined by the porosimeter. Otherwise, additional scans are performed in the low-pressure range (7–165 kPa), and the volume-average pore diameter is calculated according to the following equation:

[0101] d=2[v1r1 / w1+v2r2 / w2] / [v1 / w1+v2 / w2]

[0102] Where d is the volume average pore diameter; v1 is the total volume of mercury that penetrates in the high-pressure range; v2 is the total volume of mercury that penetrates in the low-pressure range; r1 is the volume average pore radius determined by the high-pressure scan; r2 is the volume average pore radius determined by the low-pressure scan; w1 is the weight of the sample that has undergone the high-pressure scan; and w2 is the weight of the sample that has undergone the low-pressure scan.

[0103] In determining the volume-average pore diameter in the above-described process, the maximum pore radius detected is sometimes noteworthy. If performed, this is taken from a low-pressure range scan; otherwise, from a high-pressure range scan. The maximum pore diameter is twice the maximum pore radius. Due to some production or processing steps, such as coating, printing, impregnation, and / or bonding processes, at least some pores of the microporous material may be filled, and due to some irreversible compression of the microporous material during these processes, parameters regarding porosity, volume-average pore diameter, and maximum pore diameter of the microporous material should be determined before applying one or more of these production or processing steps.

[0104] To prepare microporous materials, fillers, polyolefin polymers (typically in solid form such as powders or granules), processing plasticizers, and small amounts of lubricants and antioxidants are mixed until a substantially homogeneous mixture is obtained. The weight ratio of fillers to polymers used to form this mixture is substantially the same as that of the microporous material substrate to be prepared. This mixture, along with additional processing plasticizers, is introduced into the heated barrel of a screw extruder. A die (e.g., a sheeting die) is attached to the extruder to form the desired final shape.

[0105] In the example manufacturing process, as the material is formed into a sheet or film, the continuous sheet or film formed by the die is pushed onto a pair of heated calendering rolls. These rolls cooperate to form a continuous sheet with a thickness lower than the continuous sheet leaving the die. The final thickness may depend on the desired end application. Microporous materials may have thicknesses ranging from 0.7 to 18 mils (17.8 to 457.2 μm), such as 0.7 to 15 mils (17.8 to 381 μm), 1 to 10 mils (25.4 to 254 μm), or 5 to 10 mils (127 to 254 μm), and exhibit a foaming point of 1 to 80 psi based on ethanol. For example, microporous materials can have thicknesses of 6 mils (145 μm), 7 mils (178 μm), 8 mils (203 μm), 10 mils (254 μm), 12 mils (305 μm), 14 mils (356 μm) or 18 mils (457 μm).

[0106] Optionally, the sheet exiting the calender rolls may then be stretched in at least one stretching direction above the elastic limit. Alternatively, stretching may be performed immediately during or after exiting the tablet press head, or during calendering, or multiple times during manufacturing. Stretching may be performed before extraction, after extraction, or both. Additionally, stretching may occur during the application of the first and / or second processing compositions, as will be described in more detail below. Stretched microporous material substrates can be produced by stretching intermediates in at least one stretching direction above the elastic limit. Typically, the stretch ratio is at least 1.1. In many cases, the stretch ratio is at least 1.5. Preferably, it is at least 2. Often, the stretch ratio ranges from 1.2 to 15. Typically, the stretch ratio ranges from 1.5 to 10. Typically, the stretch ratio ranges from 2 to 6.

[0107] The temperature at which stretching is completed can vary widely. Stretching can be performed at ambient room temperature, but elevated temperatures are typically used. The intermediate product can be heated before, during, and / or after stretching using any wide variety of techniques. Examples of these techniques include radiant heating, such as radiant heating provided by electric or gas-fired infrared heaters; convective heating, such as convective heating provided by circulating hot air; and conductive heating, such as heating provided by contact with heated rollers. The temperature measured for temperature control purposes may vary depending on the equipment used and individual preferences. For example, temperature measuring devices may be placed to determine the temperature of the infrared heater surface, the internal temperature of the infrared heater, the air temperature at a point between the infrared heater and the intermediate product, the temperature of the circulating hot air at various points within the equipment, the temperature of the hot air entering or leaving the equipment, the temperature of the roller surface used during stretching, the temperature of the heat transfer fluid entering or leaving such rollers, or the film surface temperature. Typically, one or more temperatures are controlled such that the intermediate product is stretched substantially uniformly, and the variation (if any) in the film thickness of the stretched microporous material is within acceptable limits, so that the amount of stretched microporous material exceeding those limits is acceptablely low. Obviously, the temperature used for control purposes may or may not be close to the temperature of the intermediate product itself, as they depend on the nature of the equipment used, the location of the temperature measuring device, and the properties of the substance or the object whose temperature is being measured.

[0108] Considering the location of the heating device and the linear velocity typically used during stretching, a varying temperature gradient may or may not exist across the entire thickness of the intermediate product. Similarly, due to such linear velocities, measuring these temperature gradients is impractical. The existence of a varying temperature gradient (when it occurs) makes it unreasonable to mention a single film temperature. Therefore, the measurable film surface temperature is best suited for characterizing the thermal state of the intermediate product.

[0109] Although the widths of intermediate products are typically the same during stretching, they can be intentionally altered, for example, to compensate for intermediate products with wedge-shaped cross-sections spanning the sheet. The film surface temperature along the length of the sheet can be the same or different during stretching.

[0110] The membrane surface temperature at the end of stretching can vary widely, but it typically ensures that the intermediate product is stretched substantially uniformly, as explained above. In most cases, the membrane surface temperature during stretching ranges from 20°C to 220°C. Typically, this temperature range is from 50°C to 200°C. Preferably, it is from 75°C to 180°C.

[0111] Stretching can be performed in a single step or multiple steps as needed. For example, when an intermediate product is stretched in one direction (uniaxial stretching), stretching can be completed by a single stretching step or a series of stretching steps until the desired final draw ratio is obtained. Similarly, when an intermediate product is stretched in two directions (biaxial stretching), stretching can be performed by a single biaxial stretching step or a series of biaxial stretching steps until the desired final draw ratio is obtained. Biaxial stretching can also be performed by a series of one or more uniaxial stretching steps in one direction and one or more uniaxial stretching steps in the other direction. The biaxial stretching steps and uniaxial stretching steps for simultaneously stretching the intermediate product in two directions can be performed sequentially in any order. Stretching in multiple directions is also conceivable. As can be seen, there are many possible arrangements of steps. Other steps, such as cooling, heating, sintering, annealing, winding, unwinding, etc., can be optionally included throughout the process as needed.

[0112] Various types of stretching apparatus are well known and can be used to perform the stretching of intermediate products. Uniaxial stretching is typically accomplished by stretching between two rollers, where the second or downstream roller rotates at a greater circumferential speed than the first or upstream roller. Uniaxial stretching can also be performed on a standard tenter frame. Biaxial stretching can be achieved by stretching simultaneously in two different directions on a tenter frame. However, more generally, biaxial stretching is accomplished by first performing uniaxial stretching between two rollers rotating at different speeds, as described above, and then performing uniaxial stretching in different directions using a tenter frame, or by performing biaxial stretching using a tenter frame. The most common type of biaxial stretching involves two stretching directions that are approximately right-angled to each other. In most cases where continuous sheets are stretched, one stretching direction is at least approximately parallel to the long axis (longitudinal direction) of the sheet, while the other stretching direction is at least approximately perpendicular to the longitudinal direction and lies in the plane of the sheet (transverse direction).

[0113] Stretching the sheet prior to the extraction of the processing plasticizer allows for thinner films with larger pore sizes than conventionally processed microporous materials. It is also believed that stretching the sheet prior to the extraction of the processing plasticizer minimizes post-processing thermal shrinkage. It should also be noted that the stretching of the microporous material can be performed at any point before, during, or after the application of the first treatment composition (described below), and / or before, during, or after the application of the second treatment composition. The stretching of the microporous material can occur once or multiple times during the processing.

[0114] The product is conveyed to the first extraction zone, where the processing plasticizer is substantially removed by extraction with an organic liquid that is a good solvent for the processing plasticizer, a poor solvent for the organic polymer, and is more volatile than the processing plasticizer. Typically, but not necessarily, both the processing plasticizer and the organic extraction liquid are substantially immiscible with water. The product is then conveyed to the second extraction zone, where the remaining organic extraction liquid is substantially removed by steam and / or water. The product is then conveyed to a forced air dryer to substantially remove residual water and any remaining residual organic extraction liquid. Microporous material, when in sheet form, can be conveyed from the dryer to the take-up rollers.

[0115] Processing plasticizers exhibit almost no solubilizing effect on thermoplastic organic polymers at 60°C, moderate solubilizing effect at elevated temperatures around 100°C, and significant solubilizing effect at higher temperatures around 200°C. They are liquids at room temperature and are typically processing oils, such as paraffin oils, naphthenic oils, or aromatic oils. Suitable processing oils include those conforming to ASTM D 2226-82, types 103 and 104. Most commonly used are those with pour points below 22°C or below 10°C according to ASTM D 97-66 (re-approved in 1978). Examples of suitable oils include... 412 and 371 Oil (Shell Oil Company (Houston, Texas)) is a solvent-refined and hydrogenated oil derived from naphthenic crude oil. Other materials, including phthalate plasticizers such as dibutyl phthalate, bis(2-ethylhexyl) phthalate, diisodecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, and ditridecyl phthalate, are expected to be satisfactorily used as processing plasticizers. The processing oil may be a white mineral oil, such as Sonneborn Britol 50T (Sonneborn LLC (Petrolia, Pennsylvania)) and / or Citgo Tufflo 6056 (Citgo Oil Company (Houston, Texas)).

[0116] Many organic extraction liquids exist that can be used in the manufacturing process of microporous materials. Examples of suitable organic extraction liquids include, but are not limited to, 1,1,2-trichloroethylene; perchloroethylene; 1,2-dichloroethane; 1,1,1-trichloroethane; 1,1,2-trichloroethane; dichloromethane; chloroform; 1,1,2-trichloro-1,2,2-trifluoroethane; isopropanol; diethyl ether; acetone; hexane; heptane; and toluene. One or more azeotropes selected from trans-1,2-dichloroethylene, 1,1,1,2,2,3,4,5,5,5-decafluoropentane, and / or 1,1,1,3,3-pentafluorobutane can also be used. Such materials are available as VERTREL.TM.MCA (a binary azeotrope of 1,1,1,2,2,3,4,5,5,5-dihydrodecafluoropentane and trans-1,2-dichloroethylene: 62% / 38%) and VERTREL.TM.CCA (a ternary azeotrope of 1,1,1,2,2,3,4,5,5,5-dihydrodecafluoropentane, 1,1,1,3,3-pentafluorobutane and trans-1,2-dichloroethylene: 33% / 28% / 39%); Vertrel.TM.SDG (80-83% trans-1,2-dichloroethylene, 17-20% mixture of hydrofluorocarbons), all of which are available from MicroCare Corporation (New Britain, CT).

[0117] In the aforementioned process of manufacturing microporous materials, extrusion and calendering are facilitated when the filler carries a large amount of processing plasticizer. The ability of the filler particles to adsorb and retain the processing plasticizer is a function of the filler surface area. Therefore, the filler typically has a high surface area as described above. Since it is desirable to retain the filler substantially within the microporous material substrate, the filler should be substantially insoluble in the processing plasticizer and substantially insoluble in the organic extraction liquid when the microporous material substrate is manufactured through the aforementioned process. The residual processing plasticizer content is typically less than 15% by weight of the resulting microporous material, and this can be further reduced to, for example, less than 5% by weight by additional extraction using the same or different organic extraction liquids. The resulting microporous material can be further processed according to the desired application.

[0118] The conductive ink may include a resin and a conductive material. The conductive ink may be prepared from a mixture comprising the resin, the conductive material, and a solvent. The mixture may include at least one of the following: a drying additive, a plasticizer, a rheology modifier, and an adhesion promoter.

[0119] The solvent may include at least one of aromatic compounds, ketones, esters, ethers, and alcohols. The solvent is soluble in resins. The solvent may have an evaporation rate in the range of 0.005-6.3, for example, 1-6.3, compared to butyl acetate (evaporation rate = 1). The solvent may be free of amine-containing compounds. Examples of usable solvents include, but are not limited to: diethyleneglycol monoethyl acetate (e.g., DE acetate, from Eastman Chemical Company (Kingsport, TN)), γ-butyrolactone, propylene glycol monoethyl ether acetate (e.g., PM acetate, from Eastman Chemical Company (Kingsport, TN)), ethylene glycol monobutyl ether acetate (e.g., EB acetate, from Eastman Chemical Company (Kingsport, TN)), 2-butoxyethanol, diesters, propylene carbonate, and heavy aromatic naphtha solvents (e.g., Aromatic 150 and / or Aromatic 200).

[0120] The resin may include a flexible or elongated material. When the resin is applied to a substrate and incorporated (cured and / or dried) to form a coating, it may elongate by at least 50%, such as at least 100%, compared to its original length and / or width. When the resin is applied to a substrate and incorporated (cured and / or dried) to form a coating, it may elongate by 50-1000%, such as 100-1000%, compared to its original length and / or width.

[0121] The resin may include at least one of the following: rubber-containing resins (e.g., styrene-butadiene rubber, methylbutadiene rubber, etc.), vinyl chloride-containing resins (e.g., vinyl chloride copolymers), and polyesters. The resin may include styrene-ethylene-butene-styrene block copolymers. The resin may include vinyl chloride / acrylate copolymers. The resin may include at least one of polystyrene, acrylics, polyurethanes, polyvinyl polymers, natural and / or synthetic rubbers, and copolymers thereof. The resin may include mixtures of vinyl chloride-containing resins and polyesters. The resin may include mixtures of vinyl chloride-containing resins and polyesters. The resin may include halogenated polymers, chlorinated polyolefins, polyesters, acrylics, rubbery polymers, and mixtures thereof. The polymer may be water-based and / or solvent-based.

[0122] Suitable commercial examples of resins incorporated into conductive inks include styrene-based polymers, non-limiting examples of which are available under the following trade names. (Concept Polymer Technologies, Inc. (AppleValley, CA)), (Nova Chemicals (Calgary, Canada)), G(KratonCorporation(Houston,TX)),Multibase (Dow Corning) (Chevron Phillips Chemical), and (Dexco Polymers (Plaquemine, LA)). Vinyl chloride copolymers, such as vinyl chloride / acrylate copolymers, for example... E / A grade (Wacker Polymers (Calvert City, KY)), vinyl chloride / vinyl acetate and vinyl chloride / hydroxyl-modified vinyl acetate copolymers, such as products available from Kunshan PG Chem Company, Ltd. (Huizhou, China).

[0123] The conductive material may include at least one of silver, gold, nickel, aluminum, copper, iron-containing materials, alloys, and carbon-based materials (e.g., organic conductive materials such as polyaniline (PANI) or polypyrrole, graphite / graphene, and carbon nanotube types). The conductive material may be in the form of a metal sheet, or may have a spherical, spear-shaped, or tubular shape. The conductive material may include silver sheets or silver-coated copper sheets, or any sheet containing any of the other conductive materials described above. The conductive material may include multi-peaked conductive particles, including but not limited to mixtures of spheres and sheets, and mixtures of spheres, sheets, and tubular shapes.

[0124] Suitable examples of silver and silver-coated copper conductive materials include, but are not limited to, those available from Ferro Advanced Materials (Mayfield Heights, OH), Ames Goldsmith (South Glens Falls, NY), Johnson Matthey (London, UK), Technic Inc. (Cranston, RI), and Metalor (Neuchatel, Switzerland).

[0125] Conductive materials can have a D50 particle size of less than 100 μm, measured using a Microtrac S3500 particle size analyzer. Conductive materials can have a D50 particle size greater than 0.5 μm. Conductive materials can have a D50 particle size of 0.5-100 μm, for example, 30-40 μm, 33-37 μm, or 10-70 μm. Conductive materials can have a D50 particle size of less than 70 μm, for example, less than 50 μm, less than 40 μm, less than 30 μm, less than 20 μm, or less than 15 μm.

[0126] The ratio of conductive material to resin in the conductive ink can range from 0.25:1 to 20:1, for example, 0.25:1 to 6:1, 1:1 to 6:1, 1:1 to 3.5:1, for example, 1.5:1 to 2.5:1.

[0127] When the conductive ink is applied to the substrate to form the article with electrical shielding, the conductive material from the conductive ink can be at a rate of 5 g / m 2 Up to 500g / m 2 For example, 7g / m 2 Up to 500g / m 2 The amount of conductive material present on the surface of the substrate is such that when the conductive ink is applied to the substrate to form the electrically shielded article, the conductive material from the conductive ink can be present at a rate of at least 5 g / m². 2 For example, at least 7g / m 2 The amount of conductive ink present on the surface of the substrate. The conductive ink may be present on the surface of the substrate within the area on which the conductive ink has been applied.

[0128] The conductive ink can be patterned, such as a grid pattern, and applied to the substrate (see [reference]). Figure 1A The grid pattern may include grid lines spaced 0.1-10 mm apart, such as 1-3 mm intervals. As used herein, the grid is not limited to a network of uniformly spaced horizontal and vertical lines, but includes any network defined by any number and type of shape. Conductive ink can be applied to a substrate as a continuous coating, for example, by applying it to an area of ​​the substrate or the entire substrate via die coating (see [link to documentation]). Figure 1B Including conductive ink on a portion of the substrate allows the target portion to become a shielded area of ​​the substrate, while other portions of the substrate that do not contain conductive ink may not be shielded. The conductive ink applied to the substrate can form conductive channels on the shielded portion of the substrate. The conductive ink can be applied to the substrate by, but is not limited to, the following application methods: screen printing, spraying, stencil (overcoating), gravure printing, flexographic printing, inkjet printing, digital printing, and 3D printing, and combinations thereof.

[0129] For example, when the conductive ink is applied via overcoating, stencil coating, spraying, or other printing / coating techniques, it can be applied to a substrate to form a conductive ink film with a thickness ranging from 0.25 mils to 5.0 mils (approximately 6.25 μm to 130 μm), such as 0.25 mils to 2.0 mils (approximately 6.25 μm to 51 μm). For example, when the conductive ink is applied to the substrate in a pattern (e.g., a grid pattern), the film thickness can range from 1 μm to 20 μm.

[0130] As previously described, the article of electrical shielding may include the substrate and the conductive ink applied to the substrate.

[0131] When a force is applied to the electrically shielded article, the electrically shielded article can be stretched from a first orientation with a first signal loss to a second orientation with a second signal loss. When the force is removed, the article can be relaxed to substantially the first orientation (within 5%, such as within 1%) and substantially the first signal loss (within 5%, such as within 1%).

[0132] The electrically shielded article may exhibit a signal loss of at least 5 dBm (in the first orientation, second orientation, or both) over a maximum of 4 mm, such as at least 10 dBm, at least 15 dBm, or at least 25 dBm. Signal loss can be determined by the following NFC attenuation test. The following materials are used for NFC attenuation testing:

[0133] Material quantity 13.56MHz coil 2 12-inch UFL cable 2 Acrylic Paper Holder 1 wooden spacers 4 Plastic spacer 2 Network Analyzer (Agilent 8753E) 1

[0134] UFL cables are connected to the coils. One UFL cable is connected to port 1 of the network analyzer, and the other UFL cable is connected to port 2 of the network analyzer. Wooden spacers are placed on either side of the acrylic paper holder. Each coil is placed in a plastic spacer on the opposite side of the acrylic paper holder, 4 inches from the acrylic paper holder. The network analyzer is set to scan CW time at a frequency of 13.56MHz and a power level of 0dBm. NFC attenuation testing is then performed as follows:

[0135] 1. Set the network analyzer to measure S11 and record baseline dB values.

[0136] 2. Then set the network analyzer to measure S22 and record baseline dB values.

[0137] 3. Then set the network analyzer to measure S12 and record baseline dB values.

[0138] 4. Then place the product to be tested in an acrylic paper holder.

[0139] 5. Repeat steps 1-3 to record S11, S22 and S12 for each tested electrically shielded article to determine δ from the baseline reading, in order to determine the signal loss of the tested electrically shielded article.

[0140] The electrically shielded article can exhibit a detuning effect, causing the tuning characteristics (e.g., the resonant frequency or Q factor associated with the antenna) to be altered near a substrate coated with conductive ink compared to the same article without a substrate coated with conductive ink.

[0141] Detuning effects and signal loss can be determined through the following NFC detuning tests. The following materials are used for NFC detuning testing:

[0142] Material quantity 13.56MHz coil 2 7-foot UFL cable 2 PVC pipe spacer 1 Plastic spacer 2 per size (22, total) Network Analyzer (Agilent 8753E) 1 ruler or meter stick 1

[0143] The UFL cable is connected to the coil. Adhesive is used to connect the coil to each end of a PVC pipe fitting cut to 2 inches in length. Small notches are cut in the PVC pipe to allow the cable to fit into the notches. The assembly is placed on a flat surface with the PVC pipe in a vertical position, so that one coil is near the top of the assembly and the other coil is at the bottom of the PVC pipe. The coil at the bottom of the assembly is connected to port 1 on the network analyzer, and the coil at the top of the PVC pipe is connected to port 2 on the network analyzer. The network analyzer is set to scan from 10MHz to 25MHz at 0dBm power. The NFC detuning test is then performed as follows:

[0144] 1. The network analyzer is set to measure S11 and record baseline dB values ​​at 13.56MHz.

[0145] 2. Then the network analyzer was set to measure S22 and record baseline dB values ​​at 13.56MHz.

[0146] 3. Then set the network analyzer to measure S12 and record baseline dB values ​​at 13.56MHz.

[0147] 4. Then place the product to be tested, which is electrically shielded, under the assembly (between the assembly and the flat surface).

[0148] 5. Repeat steps 1-3 to record S11, S22 and S12 for each tested electrically shielded article to determine δ from the baseline reading to determine the detuning of the tested electrically shielded article for the distance between the electrically shielded article and the assembly.

[0149] 6. The network analyzer is set to measure S11 and find the lowest dBm point on that frequency scan, and record that dBm point and frequency to determine the detuning effect and signal loss.

[0150] 7. Two 1mm spacers are placed between the assembly being tested and the electrically shielded product.

[0151] 8. Repeat steps 5-7 for each pair of spacers (to measure the detuning effect and signal loss at different distances (0-11mm) between the electrically shielded product and the assembly).

[0152] According to the above NFC detuning test, the electrically shielded article can exhibit a signal loss of at least 5dBm at 0mm, up to 2mm or up to 4mm for the self-assembled part (on the first orientation, the second orientation or both), such as at least 10dBm, at least 15dBm or at least 25dBm.

[0153] The electrical shielding product can be in the form of a sheet. The electrical shielding product can be rolled into a master roll or a slit roll.

[0154] The electrical shielding product can be subjected to a variety of finishing techniques, such as folding, molding, perforation, stitching and / or bonding, without significantly altering the shielding effectiveness of the electrical shielding product (less than 5%, such as less than 1%, or 0%, compared to its unaltered state).

[0155] The electrically shielded article may be printable. Images can be applied to the coated and uncoated surfaces of the electrically shielded article using various printing techniques, including, but not limited to, offset printing, flexographic printing, digital printing, inkjet printing, laser printing, intaglio printing, and / or gravure printing.

[0156] refer to Figure 2 The image shows an article 10 of electrical shielding described herein. The article 10 of electrical shielding may include a substrate 12 described herein and a conductive ink 14 described herein applied to at least a portion of the substrate 12.

[0157] refer to Figure 3 The image shows an identification device 20 including an electrically shielded article 10. The identification device 20 may include a front cover 22 and a rear cover 24, and an interceding e-data page 26 between the front cover 22 and the rear cover 24. The front cover 22 may include the electrically shielded article 10, for example, on its internal portion. The rear cover 24 may include an antenna 28 printed thereon, for example, on its internal portion. The e-data page 26 may include data associated with the identification device 20, such as data associated with a user and / or the user's identity. The rear cover 24 may additionally and / or alternatively include the electrically shielded article 10. When the identification device 20 is off (not shown), the electrically shielded article 10 may shield data associated with the identification device 20 (e.g., stored on an embedded RF driver chip), and when the identification device 20 is on (see [link to relevant documentation]). Figure 3 Data can be read through a receiver (e.g., an RF receiver).

[0158] The same page and / or cover of the identification device 20 may include electrically shielded article 10 and antenna 28, or electrically shielded article 10 and antenna 28 may be included on separate pages and / or covers. Electrically shielded article 10 may be included on the front cover 22 of the identification device 20, on the electronic data page 26 of the identification device 20, on another insert of the identification device 20, and / or on the rear cover 24 of the identification device 20. The identification device 20 may include machine-readable travel documents (e.g., passports), government-issued national identification cards, driver's licenses, voter registration cards, birth certificates, social security cards, health insurance cards, university identity cards, employee identity cards, university diplomas, certificates or transcripts, or any other device containing personally identifiable information.

[0159] The electrically shielding article may be included in a system that at least partially shields a space. The electrically shielding article may be included as tape on packaging, such as packaging to be shipped, to electrically shield the contents of the packaging. The electrically shielding article may be included as wallpaper on the walls and / or ceilings and / or floors of a residence or building to shield the space of that residence or building (e.g., a secure room). The electrically shielding article may include bags, grounding tape, circuit boards, driver chips, antennas, electronic devices, or any other products that may be beneficial for RF (or other ranges of electromagnetic wavelengths) protection.

[0160] refer to Figure 9 The electrically shielded box 30 may include electrically shielding tape 32, on which an article of electrically shielding is adhered as an electrically shielding material, to at least a portion of the box 30. The tape 32 can prevent the contents of the box 30 from being read (e.g., electronic data stored in the box 30 cannot be read by a suitable receiver), and the box 30 is sealed by the tape 32. The tape 32 can be applied to the entire surface of the box 30 or to selected areas of the surface of the box 30. The tape 32 can be applied to at least one seam of the box 30.

[0161] refer to Figure 10 The electrically shielded space 34 may include electrically shielding wallpaper 36 applied to at least a portion of the walls and / or ceiling of the electrically shielded space 34. The wallpaper 36 may shield the contents of the space 34 from being read (e.g., electronic data stored in the space 34 may not be read by a suitable receiver). The wallpaper 36 may be applied to the entire surface of the space 34 or to selected areas of the surface of the space 34.

[0162] refer to Figure 11 The bag 40 for electrical shielding of the electronic payment card 42 may include an electrical shielding material 44. The electrical shielding material 44 may prevent the contents of the bag 40 (e.g., the electronic payment card 42) from being read (e.g., the electronic data stored in the electronic payment card 42 from being read by a suitable receiver).

[0163] refer to Figure 12 The image shows a roll 46 of electrical shielding material 48. The electrical shielding material 48 on roll 46 may include electrical shielding tape and / or electrical shielding paper, which can be applied by a user to a desired article. The electrical shielding material 48 may include an adhesive configured to bond the electrical shielding material 48 to the surface of the article.

[0164] The electrically shielded article described herein can be prepared by applying the conductive ink to a flexible and / or elongated substrate. When the conductive ink is applied to the substrate, the conductive material in the conductive ink may be present on the substrate in an amount of at least 5 g / m². 2 The electrically shielded product can provide a signal loss of at least 5 dBm within a maximum of 4 mm, according to NFC detuning tests.

[0165] Example

[0166] The following examples are provided to illustrate the principles of the invention. The invention should not be construed as being limited to the specific embodiments given.

[0167] Part I: Preparation of Conductive Ink

[0168] Example 1: Preparation of Silver Conductive Ink Formulation

[0169] Table 1. Ink Formulation

[0170] <![CDATA[ Components ]]> <![CDATA[ weight <!-- 15 -->]]> 2-Butoxyethyl acetate 18.74 <![CDATA[PVC resin 1 > 6.25 <![CDATA[LANCO PP 1362D 2 ]]> 0.35 <![CDATA[Silver pigment 3 > 65.98 2-Butoxyethyl acetate 8.65 Propylene glycol monomethyl ether acetate 4.69 hydroquinone 0.30

[0171] 1 Blend of vinyl chloride / 2-hydroxypropyl acrylate copolymer, CAS#[53710-52-4].

[0172] 2 Modified polypropylene wax is available from The Lubrizol Corporation (Wickliffe, OH).

[0173] 3 Silver flake pigment with a D50 of approximately 4 μm.

[0174] First, PVC resin is dissolved in 2-butoxyethyl acetate in the first amount according to Table 1 under high-shear mixing. Once the PVC is dissolved, wax is added, followed by silver pigment under low to medium stirring. The resulting suspension is passed through a 3-roll mill in a single pass, and then the final amounts of 2-butoxyethyl acetate, propylene glycol monomethyl ether acetate, and hydroquinone are added to produce a final ink composition comprising a pigment to PVC resin (“binder”) ratio of 10.56.

[0175] Example 2: Preparation of a silver-coated copper conductive ink formulation.

[0176] Table 2. Ink Formulation

[0177] <![CDATA[ Components ]]> <![CDATA[ weight ]]> Toluene 24.79 xylene 24.79 <![CDATA[Styrene-based resin 4 > 8.75 <![CDATA[Silver-coated copper 5 > 26.46 Isopropanol, anhydrous 1.62 Toluene 6.79 xylene 6.79

[0178] 4 Ternary block styrene-ethylene-butene-styrene (SEBS) linear polymer having a ternary block structure containing approximately 29-30% styrene.

[0179] 5 Copper flakes coated with 15% silver have a D50 particle size of approximately 30 to 40 μm.

[0180] Combine the first three ingredients from Table 2 and stir until the resin is completely dissolved. Adjust the solids to 16% with additional toluene. Then slowly add the metal flakes to avoid dust, and rinse the container walls with isopropanol. Stir the resulting mixture under moderate stirring to incorporate the pigment. Add the remaining toluene and xylene to provide a final ink composition with 35% solids and a pigment-to-binder ratio of 3.0.

[0181] Part II: Coating of the substrate.

[0182] Part IIa. Screen printing process.

[0183] In a roll-to-roll process, the ink formulation of Example 1 was applied via a rotating screen. The ink formulation was propelled onto the substrate by a squeegee at a linear speed of 15 FPM through the desired mesh screen. The coated material was then subjected to a heated oven at 120°C for a total residence time of 3 minutes to produce a screen-printed substrate with a mesh pattern, which was then introduced onto a second roll. Samples listed in Table 3 were prepared using the screen printing method. The line width of each mesh was 7-10 micrometers.

[0184] Table 3. Samples of screen printing.

[0185] sample <![CDATA[Substrate 6 > Grid size <![CDATA[Conductive material (g / m 2 )]]> Sample 1 Teslin SP700 1mm 22 Sample 2 Teslin SP1400 1mm 22 Sample 3 Teslin SP600 3mm 7

[0186] 6 all The substrate was sourced from PPG Industries, Inc. (Pittsburgh, Pennsylvania).

[0187] Part IIb. Channel coating process.

[0188] The ink formulation of Example 2 was added to a storage tank pressurized with an air cushion. The ink was pushed into a mold and conveyed to a substrate passing underneath at a rate that produced the desired film thickness. The coated substrate was dried in an oven at 120°C for 2 minutes to produce a fully (overcoated) coated substrate. Samples listed in Table 4 were prepared by the mold process:

[0189] Table 4. Samples of grooved coating

[0190] <![CDATA[ sample ]]> <![CDATA[ substrate ]]> <![CDATA[ film thickness ]]> <![CDATA[ Conductive materials (g / m 2 ) ]]> Sample 4 Teslin SP600 1.25 mils 169 Sample 5 Teslin SP1400 0.75 mils 101 Sample 6 Teslin SP1400 1.25 mils 169

[0191] Figure 4 The transmission shielding effectiveness (signal loss) of samples 1, 5, and 6 is shown, with signal loss determined based on NFC attenuation testing. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 4 It can be seen that the sample exhibits good shielding effectiveness and can achieve different levels of shielding effectiveness.

[0192] Figure 5 The detuning of Sample 4 is shown in the 1.5 mm and 3.0 mm gaps (between the shielding material and the receiving antenna) compared to a control with a reactive antenna response lacking any shielding material. Sample 4 is integrated into a booklet using the same cover and adhesive material as a standard passport, but excluding the passport electronics. Antenna attenuation was determined according to NFC detuning tests. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 5 It can be seen that using sample 4 achieved the following beneficial results: (1) a strong change in the resonant frequency (attenuation peak) when shielding is present, (2) a strong change in attenuation when shielding is present, and (3) a broadening of the peak width (also known as the q-factor). At least these factors indicate that the antenna pair is detuned, effectively interfering with communication.

[0193] Figure 6A and 6B The signal loss and detuning resonant frequency at 13.56 MHz, as a function of distance compared to control copper, are shown for samples 2 and 6 when the booklet is open. The signal loss and detuning resonant frequency were determined according to NFC detuning tests. (As can be seen from...) Figure 6A and 6B It can be seen that all three samples provide essentially the same level of signal interception and detuning.

[0194] Tables 5 and 6 below show some performance characteristics of the control (unmasked Teslin SP1400) compared to samples 5 and 6.

[0195] Table 5. Elongation and Tensile Strength

[0196]

[0197] Compared with the control samples, samples 5 and 6 showed improved elongation and tensile strength. The tensile strength of samples 5 and 6 increased by 20-30%. Longitudinal and transverse elongation were determined using an Instron universal testing machine, model 3343 or 3345, manufactured by Instron (Norwood, MA).

[0198] Table 6. Heat Shrinkage, Stiffness, Tear Resistance

[0199]

[0200] The stiffness of samples 5 and 6 was increased by 40-85% compared to the control samples. The tear resistance of samples 5 and 6 was increased by 15-30% compared to the control samples. The thermal shrinkage of samples 5 and 6 was reduced by approximately 30% compared to the control samples. Stiffness was measured using a Thwing Albert Company (Philadelphia, PA) Model 211-300 Handle-O-Meter. Tear resistance was measured using an Elemendorf tear tester (Model 60-2001) manufactured by Thwing Albert Company (Philadelphia, PA).

[0201] Heat shrinkage was measured by cutting the sample longitudinally or transversely to a length of 355.5 mm. The cut sheet was placed in an oven preheated to 135°C between two preheated stainless steel sheets and left in the oven for 15 minutes. The sample was then removed from the oven, separated, and allowed to cool for 5 minutes. The length of the sheet (in millimeters) was measured with a ruler to determine the % shrinkage rate.

[0202] For sample 4, the signal loss as a function of % elongation was calculated. The signal loss was calculated by assuming a linear relationship between resistance (measured as described below) and signal loss, where resistance and signal are derived from... Figure 6A The resistance was obtained by fitting the signal loss to the relevant test results. Figure 7 These results are shown. For example, they can be obtained from... Figure 7 It can be seen that sample 4 maintains a high level of shielding effectiveness even when it is stretched.

[0203] For sample 4, a four-point probe was used to measure the resistance, which was used as the transverse ( Figure 8A ) and longitudinal ( Figure 8B The percentage elongation measured on the surface is a function of the elongation percentage. For example, it can be obtained from... Figure 8A and 8B As can be seen, the shielding material in Sample 4 can be stretched and maintains significant conductivity. After relaxation, the shielding material in Sample 4 returns to near-baseline shielding effectiveness. Minimal resistance change occurs at elongation exceeding 2%. In these figures, the resistance was measured using a Keithley 2450 source meter when the material was stressed (stretched) to the indicated elongation, and then measured again after 24 hours of relaxation to its previous state.

[0204] Although specific embodiments of the invention have been described above for illustrative purposes, it will be apparent to those skilled in the art that various changes may be made to the details of the invention without departing from the invention as defined in the appended claims.

Claims

1. An electrically shielded article, comprising: Flexible and elongated substrates comprising polyolefins; and A conductive ink, comprising a resin and a conductive material, is applied to at least a portion of the flexible and elongated substrate. The resin comprises at least one of the following: styrene-butadiene rubber and styrene-ethylene-butene-styrene block copolymer; The conductive material comprises at least one of silver, gold, nickel, aluminum, copper, and iron. The conductive material in the conductive ink is 5 to 101 g / m 2 The amount exists in this flexible and elongated substrate. The electrically shielded product exhibits a signal loss of at least 5 dBm in up to 4 mm according to the NFC detuning test.

2. The electrically shielded article of claim 1, wherein the conductive material in the conductive ink is at a concentration of 7 g / m³. 2 Up to 22 g / m 2 The amount exists on the surface of this flexible and elongated substrate.

3. The electrically shielded article of claim 1, wherein the conductive ink is prepared from a mixture comprising the resin, the conductive material and the solvent.

4. The electrically shielded article of claim 3, wherein the solvent comprises at least one of an aromatic compound, a ketone, an ester, and an alcohol.

5. The electrically shielded article of claim 3, wherein the solvent does not contain amine-containing compounds.

6. The electrically shielded article of claim 1, wherein the ratio of the conductive material to the resin in the conductive ink is from 0.25:1 to 6:

1.

7. The electrically shielded article of claim 1, wherein the ratio of the conductive material to the resin in the conductive ink is 1.5:1 to 2.5:

1.

8. The electrically shielded article of claim 1, wherein the resin comprises a styrene-ethylene-butene-styrene block copolymer.

9. The article of electrical shielding according to claim 1, wherein the conductive material comprises at least one selected from silver, gold, nickel, aluminum, copper and iron-containing materials.

10. The article of electrical shielding according to claim 1, wherein the conductive material comprises an alloy.

11. The article of electrical shielding according to claim 1, wherein the flexible and elongated substrate is elongated by at least 50%.

12. The article of electrical shielding according to claim 1, wherein the flexible and elongated substrate comprises pores.

13. The article of electrical shielding according to claim 12, wherein the flexible and elongated substrate comprises a filler.

14. The article of electrical shielding according to claim 13, wherein the filler comprises a siliceous material.

15. The electrically shielded article of claim 1, wherein the conductive ink is applied to the flexible and elongated substrate by at least one of the following methods: screen printing, spraying, stencil coating, gravure printing, flexographic printing, inkjet printing, digital printing, and 3D printing.

16. The article of electrical shielding according to claim 1, wherein the conductive ink is applied in a patterned manner to the flexible and elongated substrate.

17. The article of electrical shielding according to claim 1, wherein the conductive ink is applied as a continuous coating on the flexible and elongated substrate in a region thereof.

18. The electrically shielded article of claim 1, wherein, When a force is applied to the electrically shielded article, the electrically shielded article can be stretched from a first orientation with a first signal loss to a second orientation with a second signal loss.

19. The electrically shielded article of claim 18, wherein when the force is removed, the electrically shielded article relaxes to within 5% of the first orientation and within 5% of the first signal loss.

20. The electrically shielded article of claim 1, wherein the conductive material has a D50 particle size of 0.5 µm to 100 µm.

21. A method for preparing an electrically shielded article, comprising: Conductive ink is applied to a flexible and elongated substrate, wherein the substrate comprises a polyolefin. The conductive ink contains resin and conductive materials. The resin comprises at least one of the following: styrene-butadiene rubber and styrene-ethylene-butene-styrene block copolymer; The conductive material contains at least one of silver, gold, nickel, aluminum, copper, and iron. The conductive material in the conductive ink is 5 to 101 g / m 2 The amount exists in this flexible and elongated substrate. The electrically shielded article provides a signal loss of at least 5 dBm in up to 4 mm, according to the NFC detuning test.

22. The method of claim 21, wherein the conductive ink is applied to the flexible and elongated substrate by at least one of the following application methods: screen printing, spraying, stencil printing, gravure printing, flexographic printing, inkjet printing, digital printing, and 3D printing.

23. The method of claim 21 or 22, wherein the conductive material in the conductive ink is at a concentration of 7 g / m³. 2 Up to 22 g / m 2 The amount exists on the surface of this flexible and elongated substrate.

24. An identification device comprising an article of electrical shielding as described in claim 1.

25. The identification device of claim 24, wherein the identification device comprises a machine-readable travel document.

26. The identification device of claim 24, comprising: The first page of the article containing the electrical shield; and The second page contains the antenna.

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