Conductive materials and their methods of preparation by metallization with metal complex conductive ink compositions

Abstract

To provide conductive materials and their methods of preparation by metallization with metal complex conductive ink compositions.SOLUTION: The present disclosure provides conductive materials, including conductive textile materials such as woven or knitted fabrics, individual fibers, and woven fibers and yarns. The conductive materials comprise a substrate material, such as a textile or other suitable material, and a metal embedded in the substrate material, in particular with the metal being embedded into and below the surface of the material. Also provided are methods for producing the conductive materials. The substrate material is a thermally decomposable textile substrate material, which is decomposable at a temperature exceeding about 300°C.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Application No. 62 / 714,641, filed on Aug. 3, 2018, the disclosure of which is incorporated herein by reference in its entirety.

[0002] (Field of the Invention) The present disclosure relates to novel conductive materials and methods for their preparation by metallization of substrate materials such as textile substrate materials using metal - complexed conductive ink compositions.

Background Art

[0003] (Background of the Invention) Conductive textiles, fabrics, and other types of materials with suitable electrical and mechanical properties have been sought for many years. In particular, applications related to conductive textiles are important and numerous, including use in e - clothing and skin patches (i.e., wearable applications), EMI / RF shields, interconnects, and wires. Important metrics related to these materials are performance, aesthetics, safety, and cost. With respect to performance, a conductive textile or fabric preferably has high conductivity and, more importantly, is capable of maintaining a sufficient level of conductivity in response to dynamic stretching and distortion over thousands of cycles. The aesthetics of conductive materials are also important. Ideally, the fabrics and fibers prepared from these materials should not be like metal patches or twisted wires and should feel as similar as possible to their unmodified form. The lack of safety and toxicity is also important since many of these applications involve wearable items for consumers and medical devices. Finally, low cost, which is also related to manufacturability, is essential for high - volume consumer electronics applications that utilize such materials.

[0004] Known electronic fabrics and textile materials conventionally consist of a metallic conductive layer that either surrounds the fibers (which can subsequently be woven into a twist) or is laminated on top of the fabric. For example, see Figure 1. Such materials are typically prepared by depositing (e.g., using common printing techniques such as inkjet, screen printing, or equivalents) or sputtering a pure metal film onto the fibers or fabric. Since the metals applied by these techniques cannot penetrate the surface of the material being treated, the conductive portion of the material is essentially separate from the underlying fiber or fabric substrate.

[0005] An important commercial problem with fabrics with sputtered metallized layers is that the process is expensive and has low throughput. Additionally, the resulting metal layer is fragile and interferes with the inherent conductivity combination of the material while retaining the material's ability to stretch / distort.

[0006] On the other hand, an important commercial problem with fabrics and textiles with a deposited metal particle / polymer film top layer, while being relatively more cost-effective, is poor conductivity due to the low curing temperature required for the fabric / textile substrate, partly due to its temperature sensitivity.

[0007] In both cases, the composition and structure of the conductive fabric are limited to the top layer of metallization using standard particle-based metal inks and equivalents. This limits the mechanical and stretchability properties of the material. In other words, conductive fabrics or fibers in the market that mainly involve metals coated only on the surface will result in peeling or fragmentation during mechanical distortion, flexure, or stretching, leading to a large increase in electrical resistance. This makes current-conductive fabrics and fibers not suitable for commercial purposes.

[0008] Metal-containing fabrics, particularly silver-containing fabrics, have been reported to have antibacterial properties. See, for example, U.S. Patent Application Publication No. 2005 / 0037057A1. The silver in these fabrics is locally applied to the fabric in ionic form to provide controlled release of silver ions from the fabric through repeated washing cycles. However, fabrics treated with silver are non-conductive.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] (Summary of the Invention) Provided herein are conductive materials such as conductive fabric materials and methods for preparing the same by metallization using a metal complexed conductive ink composition.

Means for Solving the Problems

[0011] In one aspect, the present disclosure provides a conductive material comprising a substrate material and a metal embedded within the substrate material, the metal being embedded within and below the surface of the material.

[0012] More specifically, in some of the conductive materials of the present disclosure, the substrate material is a textile substrate material such as a fabric, fiber, yarn, or thread. Even more specifically, the fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material.

[0013] In some embodiments, the substrate material is a thermally decomposable substrate material, for example, the substrate material is decomposable at a temperature above about 300°C.

[0014] In some embodiments of the conductive material, the metal consists of silver, copper, gold, palladium, platinum, or an alloy, or any combination of these metals. More specifically, the metal consists of an alloy, or a combination of silver, copper, gold, palladium, or platinum, or the metal consists of silver.

[0015] Also provided in another aspect is a conductive material, which is prepared by treating a substrate material such as a textile substrate material with a metal complex conductive ink composition.

[0016] In a specific embodiment, the substrate material is a textile substrate material such as a fabric, fiber, twist, or yarn. More specifically, the fabric, fiber, twist, or yarn consists of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material. In other specific embodiments, the substrate material is a thermally decomposable material such as a substrate material that is decomposable at a temperature above about 300°C.

[0017] In some embodiments, the metal complex conductive ink composition consists of silver, copper, gold, palladium, or platinum. More specifically, the metal complex conductive ink composition consists of a combination of silver, copper, gold, palladium, or platinum, or the metal complex conductive ink composition consists of silver.

[0018] In some embodiments, the treatment is carried out at a temperature of 300°C or below. In some embodiments, the substrate material is treated with the metal complex conductive ink composition by dyeing, and in other embodiments, the substrate material is treated with the metal complex conductive ink composition by printing.

[0019] In any of the above embodiments, the conductive material may exhibit an electrical resistance of about 1,000 ohms or less after being stretched by at least about 10%. More specifically, the material may exhibit an electrical resistance of about 1,000 ohms or less over at least about 100 cycles after being stretched by at least about 10%.

[0020] In yet another aspect, the present disclosure provides a method for preparing a conductive material, including providing a substrate material such as a fabric substrate material, treating the substrate material with a metal-complexed conductive ink composition, curing the treated substrate material, and generating a metal that is embedded within the substrate material.

[0021] In a specific embodiment, the substrate material is a fabric substrate material such as a fabric, fiber, yarn, or thread. More specifically, the fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material.

[0022] In some of these embodiments, the substrate material is a pyrolytic material, for example, a substrate material that is degradable at a temperature above about 300°C.

[0023] In some method embodiments, the metal-complexed conductive ink composition consists of silver, copper, gold, palladium, or platinum. More specifically, the metal-complexed conductive ink composition consists of a combination of silver, copper, gold, palladium, or platinum, or the metal-complexed conductive ink composition consists of silver.

[0024] In some method embodiments, the substrate material is treated with the metal-complexed conductive ink composition by dyeing or printing. In some embodiments, the substrate material is treated with the metal-complexed conductive ink composition at least twice.

[0025] In some method embodiments, the curing step is carried out at about 300 °C or lower, and in some method embodiments, the curing step is carried out over about 120 minutes or less. The present invention provides, for example, the following. (Item 1) A conductive material comprising: a base material material, and a metal embedded in the base material material and consisting of a conductive material in which the metal is embedded in and below the surface of the material. (Item 2) The conductive material according to Item 1, wherein the base material material is a woven base material material. (Item 3) The conductive material according to Item 2, wherein the woven base material material is a fabric, fiber, twist, or yarn. (Item 4) The conductive material according to Item 3, wherein the fabric, fiber, twist, or yarn consists of a polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material. (Item 5) The conductive material according to Item 1, wherein the base material material is a pyrolytic woven base material material. (Item 6) The conductive material according to Item 5, wherein the base material material is decomposable at a temperature above about 300 °C. (Item 7) The conductive material according to Item 1, wherein the metal consists of silver, copper, gold, palladium, platinum, or an alloy, or any combination of these metals. (Item 8) The conductive material according to Item 7, wherein the metal consists of an alloy, or a combination of silver, copper, gold, palladium, or platinum. (Item 9) The conductive material according to Item 7, wherein the metal consists of silver. (Item 10) A conductive material, wherein the material is prepared by treating a base material with a metal-complexed conductive ink composition. (Item 11) The conductive material according to item 10, wherein the base material is a textile base material. (Item 12) The conductive material according to item 11, wherein the textile base material is a fabric, fiber, yarn, or thread. (Item 13) The conductive material according to item 12, wherein the fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material. (Item 14) The conductive material according to item 10, wherein the base material is a thermally decomposable material. (Item 15) The conductive material according to item 14, wherein the base material is decomposable at a temperature above about 300 °C. (Item 16) The conductive material according to item 10, wherein the metal-complexed conductive ink composition is made of silver, copper, gold, palladium, or platinum. (Item 17) The conductive material according to item 16, wherein the metal-complexed conductive ink composition is made of a combination of silver, copper, gold, palladium, or platinum. (Item 18) The conductive material according to item 16, wherein the metal-complexed conductive ink composition is made of silver. (Item 19) The conductive material according to item 10, wherein the treatment is carried out at a temperature of 300 °C or lower. (Item 20) The conductive material according to item 10, wherein the base material is treated with the metal-complexed conductive ink composition by dyeing. (Item 21) The conductive material according to item 10, wherein the base material is treated with the metal-complexed conductive ink composition by printing. (Item 22) The conductive material according to any one of items 1-21, wherein the material exhibits an electrical resistance of about 1,000 ohms or less after being stretched by at least about 10%. (Item 23) The conductive material according to item 22, wherein the material exhibits an electrical resistance of about 1,000 ohms or less over at least about 100 cycles after being stretched by at least about 10%. (Item 24) A method for preparing a conductive material, comprising: providing a substrate material; treating the substrate material with a metal complexed conductive ink composition; curing the treated substrate material to generate a metal embedded in the substrate material. A method comprising the above steps. (Item 25) The method according to item 24, wherein the substrate material is a textile substrate material. (Item 26) The method according to item 25, wherein the textile substrate material is a fabric, fiber, yarn, or thread. (Item 27) The method according to item 26, wherein the fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material. (Item 28) The method according to item 24, wherein the substrate material is a pyrolytic material. (Item 29) The method according to item 28, wherein the substrate material is decomposable at a temperature above about 300 °C. (Item 30) The method according to item 24, wherein the metal complexed conductive ink composition is composed of silver, copper, gold, palladium, or platinum. (Item 31) The method according to item 30, wherein the metal complexed conductive ink composition is composed of a combination of silver, copper, gold, palladium, or platinum. (Item 32) The metal complex conductive ink composition is the method according to item 30, which consists of silver. (Item 33) The substrate material is the method according to item 24, which is treated with the metal complex conductive ink composition by dyeing. (Item 34) The substrate material is the method according to item 24, which is treated with the metal complex conductive ink composition by printing. (Item 35) The substrate material is the method according to item 24, which is treated with the metal complex conductive ink composition at least twice. (Item 36) The step of curing is carried out at about 300 °C or lower, which is the method according to item 24. (Item 37) The step of curing is carried out over about 120 minutes or less, which is the method according to item 24.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0039] (Detailed Description of the Invention) (Conductive Materials) Provided herein is a conductive material, including fabrics and other materials, comprising embedded metal. In these conductive materials, the metal typically exists both as a very thin layer on the surface of the material and in a state absorbed below the surface of the material (see Figure 2). The present disclosure thus essentially provides conductive materials such as fabrics, fibers, and other materials with desirable electrical and mechanical properties.

[0040] Conductive materials are typically prepared by metallization of a substrate material, particularly a fabric substrate material and other materials capable of absorbing the applied liquid, using metal complexed conductive ink. Preferably, an ink composition, which is a particle-free ink composition, is absorbed by the substrate material such that the ink penetrates the surface of the material. Once the substrate material is properly saturated with the ink, a "curing" or "drying" process is initiated, which results in pure metal absorbed / embedded within and on the substrate material.

[0041] Conductive metal inks have previously been used in the preparation of surface-coated flexible conductive materials. For example, such inks have been developed over the past several decades as a cost-effective alternative to metal deposition in a vacuum (e.g., atomic layer deposition (ALD), chemical vapor deposition (CVD), sputtering, and equivalents) or electroplating due to the fact that they can be processed under ambient conditions. They are used in a number of applications to metallize various substrates in the fields of printed electronics and semiconductors, including rigid substrates such as glass and silicon, flexible substrates such as plastics and elastomers, and more recently, fabric or textile substrates. Important metrics regarding the usefulness of the inks in these applications include conductivity, reliability, and cost. Most of the conductive inks known in the literature are based on the dispersion of metal particles by an organic medium such as a polymer or surfactant. For example, typical conductive ink particles are provided as nanoparticles, flakes or platelets, and nanowires.

[0042] For comparison, the conductive ink composition used in the preparation of the present conductive material is preferably a particle-free metal complex ink composition. Such inks are developed, for example, by Electroninks, Inc. (Austin, TX). Particle-free metal complex ink compositions exhibit highly useful properties for the purpose of preparing fabrics and other materials with embedded conductive compositions and structures. Importantly, the particle-free ink composition allows for saturation of a suitable substrate material, ideally a material such as a fabric substrate material, that absorbs the ink and is capable of generating a conductive metal and thus a conductive material prior to curing of the ink at a low temperature.

[0043] In some embodiments, silver complexed ink compositions are used to prepare the present conductive materials, but other conceivable metal complexed ink compositions, such as those consisting of gold, copper, palladium, platinum, or combinations of these metals, may also find utility for these preparations. For example, particle-free ink compositions consisting of gold, copper, palladium, platinum, or combinations of these metals are also known. Exemplary formulations for particle-free metal complexed inks used in the present disclosure are described in PCT International Publication No. WO2015 / 160938A1 ("Conductive Ink Compositions"), PCT International Publication No. WO2018 / 118460A1 ("Copper Based Conductive Ink Composition And Method Of Making The Same"), U.S. Patent Application No. 62 / 540,829 (filed on August 3, 2017, "Conductive Ink Compositions Comprising Palladium And Methods For Making The Same"), PCT International Publication No. WO2019 / 028435A1 ("Conductive Ink Compositions Comprising Palladium And Methods For Making The Same"), U.S. Patent Application No. 62 / 540,903 (filed on August 3, 2017, "Conductive Ink Compositions Comprising Gold And Methods For Making The Same"), and PCT International Publication No. WO2019 / 028436A1 ("Conductive Ink Compositions Comprising Gold And Methods For Making The Same") (each incorporated herein by reference in its entirety).

[0044] As used herein, the terms "conductive ink composition," "conductive ink," "ink composition," "ink," or variations thereof may be used interchangeably. In some embodiments, the only conductive material within the ink composition used to prepare the conductive material of the present disclosure is a single metal, such as silver metal. In some embodiments, a plurality of conductive materials are included within the conductive ink used to prepare the present conductive material. For example, palladium can be used as a stabilizing additive within the conductive ink, based on another metal such as silver. In some embodiments, palladium is used as the primary conductive material and one or more additional conductive materials can be added for desired properties.

[0045] Also, it should be understood that the conductive ink composition used to prepare the conductive materials disclosed herein may include additional components, such as non-conductive components, to improve the properties of the ink or the properties of the conductive material prepared using the ink. For example, the conductive ink composition may include a binder or other adhesion promoter to facilitate the binding and / or adhesion of the conductive material to a substrate material, such as a specific surface, fabric, or fiber. Alternatively, or in addition, the conductive ink composition may include one or more wetting agents, detergents, or other surfactants suitable for improving the surface properties of the material being treated.

[0046] As described in detail herein, the conductive materials of the present disclosure consist of a substrate material such as a textile substrate material or other suitable porous or semi-porous material, and a metal embedded within the substrate material. In these materials, the metal is embedded below the surface of the material. Preferably, the substrate material of the conductive material is a material capable of absorbing a metal complexed conductive ink composition. As will be understood by those skilled in the art, such materials can be treated, for example, by dyeing, printing, dipping, or any other suitable method, using a particle-free metal complexed ink composition, and the ink composition will thereby infiltrate the substrate material. Upon curing of the ink, as detailed in the references listed above, the treated substrate material thus becomes a conductive material with a metal, ideally a pure metal or combination of metals, embedded below the surface of the material.

[0047] Suitable substrate materials for use in the present conductive materials include, for example, textile materials such as fabrics, fibers, yarns, or threads. In some embodiments, the fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer (e.g., "Lycra" or "Spandex"), nylon, acrylic, modified cellulose (e.g., "rayon"), polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material. Other textile substrate materials may also be found useful in the present conductive materials of the present disclosure, as will be understood by those skilled in the art.

[0048] In some embodiments, the substrate material is a suitable porous or at least semi-porous natural or synthetic material, such as polyester with additional coatings such as thermoplastic polyurethane, polyvinyl acetate, nylon, polyester, or a fluorinated coating. These materials can be provided as suitable two-dimensional materials, for example, for printing with a suitable conductive ink composition as described herein or other suitable coatings. For example, the substrate material may be provided as a two-dimensional sheet material.

[0049] One of the advantages of the conductive materials disclosed herein is that the materials can be composed of pyrolyzable materials that would typically be damaged by the methods typically used to prepare conductive fabric materials (e.g., materials prepared by depositing pure metals at high temperatures). Thus, in some embodiments, the substrate material is a pyrolyzable substrate. More specifically, the substrate material can be decomposable at a temperature above about 100°C, above about 150°C, above about 200°C, above about 250°C, or above about 300°C.

[0050] It should be understood that the term "metal," as used herein, can include both single metals as well as combinations of more than one metal. Preferably, the metal of the conductive material is in its elemental form. Ideally, the metal is a high-purity metal, e.g., at least about 90% purity, at least about 95% purity, at least about 98% purity, at least about 99% purity, or even higher purity metals. The particle-free metal complexed conductive inks described in the patent references listed above are ideally suitable for the generation of such metals in a conductive form.

[0051] The conductive materials of the present disclosure preferably exhibit various desirable electrical and mechanical properties. Specifically, in some embodiments, the material exhibits low electrical resistance. Further, the low electrical resistance is preferably maintained even when the material is subjected to stretching or distortion, which may be repeated a plurality of times, and potentially even more times.

[0052] For example, in some embodiments, the conductive material exhibits an electrical resistance of about 1,000 ohms or less, about 500 ohms or less, about 300 ohms or less, about 100 ohms or less, about 50 ohms or less, about 30 ohms or less, about 20 ohms or less, about 10 ohms or less, or even lower resistance. In particular, some of the conductive materials exhibit an electrical resistance of about 1 ohm or less.

[0053] In some embodiments, the conductive material exhibits low electrical resistance even after being stretched by a significant amount, including stretches ranging from 1% to 1,000%. In some embodiments, the conductive material exhibits low electrical resistance even after being stretched up to about 20%, up to about 40%, up to about 100%, or even more. In some embodiments, the conductive material exhibits low electrical resistance even after being stretched at least about 10%, at least about 20%, at least about 30%, at least about 50%, or even more.

[0054] In a specific embodiment, the conductive material exhibits an electrical resistance of about 1,000 ohms or less, about 100 ohms or less, about 50 ohms or less, about 20 ohms or less, about 10 ohms or less, about 5 ohms or less, about 2 ohms or less, or even about 1 ohm or less even after being stretched at least about 10%. In some embodiments, these low levels of electrical resistance are observed in conductive materials stretched up to about 20%, up to about 40%, up to about 100%, and even more.

[0055] Ideally, the conductive material exhibits low electrical resistance even after being stretched over many cycles. For example, the material can exhibit low electrical resistance even after being stretched over at least about 100 cycles, at least about 200 cycles, at least about 500 cycles, at least about 1,000 cycles, at least about 2,000 cycles, at least about 5,000 cycles, at least about 10,000 cycles, or even more cycles. In some embodiments, the conductive material exhibits an electrical resistance of about 1,000 ohms or less or about 100 ohms or less even after being stretched at least about 10% over at least about 100 cycles.

[0056] In some embodiments, the metal embedded within the fabric substrate material of the present conductive material is embedded within and below the surface of the material at an adjustable depth. For example, in some embodiments, the metal may be embedded at a depth of at least about 0.1 micron, at least about 0.3 micron, at least about 0.5 micron, at least about 1 micron, at least about 2 microns, or even deeper from the surface.

[0057] In some embodiments, the adjustable depth can be expressed as a percentage of the cross-section of the conductive material. For example, if the conductive material has a cross-section of 20 microns and the metal is embedded to a depth of 2 microns, one of ordinary skill in the art will understand that the metal is embedded to a depth of approximately 10% of the cross-section. Thus, in some embodiments, the metal may be embedded to a depth of about 0.1%, 0.3%, 0.5%, 1%, 3%, 5%, 10%, or even deeper.

[0058] Also, in some embodiments, it should be understood that the conductive materials provided herein have antibacterial properties. Without intending to be bound by theory, such properties are thought to arise from the release of metal ions, such as silver ions, as the material is used. The conductive materials of the present disclosure will likewise, inherently, release metal, including metal ions, as they are used and will therefore also exhibit antibacterial properties. Commercial examples of antibacterial metal-containing materials and treatments, such as Silvadur TM , Silpure, and Agiene® Micro Silver Crystal technology are known and understood in the art.

[0059] (Method for preparing a conductive material) In another aspect, the present disclosure provides a method for preparing the conductive materials described herein. These materials may be prepared by any suitable method, as would be understood by one of ordinary skill in the art. In some embodiments, the method used to prepare such materials includes providing a substrate material, treating the substrate material with, for example, a metal-complexed conductive ink composition, such as a textile substrate material, and curing the treated substrate material to generate a metal that is embedded within the substrate material. Preferably, the substrate material for these methods is a material capable of absorbing a particle-free metal-complexed ink composition, such as the ink compositions described above.

[0060] In some embodiments, the substrate material of the method is a thermally decomposable material. More specifically, the substrate material is decomposable at a temperature above about 100°C, above about 150°C, above about 200°C, above about 250°C, above about 300°C, or even higher temperatures.

[0061] Suitable substrate materials for use in the present preparation method include, for example, textile substrate materials such as fabrics, fibers, yarns, or threads. In some embodiments, the fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer (e.g., "Lycra" or "Spandex"), nylon, acrylic, modified cellulose (e.g., "rayon"), polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk materials. Other suitable substrate materials, including other textile substrate materials, may also find utility in the methods of the present disclosure, as would be understood by one of ordinary skill in the art.

[0062] The particle-free conductive ink composition used in the present method can be any suitable particle-free conductive ink composition. Exemplary ink compositions suitable for the present method are described in PCT International Publication No. WO2015 / 160938A1, PCT International Publication No. WO2018 / 118460A1, PCT International Publication No. WO2019 / 028435A1, PCT International Publication No. WO2019 / 028436A1, U.S. Patent Application No. 62 / 540,829, and U.S. Patent Application No. 62 / 540,903.

[0063] In a preferred method embodiment, the particle-free conductive ink composition consists of silver, copper, gold, palladium, or platinum. More preferably, the particle-free conductive ink composition consists of silver. In some embodiments, the particle-free conductive ink composition consists of a combination of metals, including a combination of silver, copper, gold, palladium, or platinum.

[0064] As detailed in the Examples section, the substrate material used in the present method can be treated with a metal-complexed conductive ink composition by various methods. In some embodiments, the substrate material is treated with a metal-complexed conductive ink composition by staining. In other embodiments, the substrate material is treated with a metal-complexed conductive ink composition by printing. In a specific embodiment, the substrate material is treated with a metal-complexed conductive ink composition by printing a plurality of times, for example, at least 2 times, at least 5 times, at least 10 times, or even more times. As will be understood by those skilled in the art, treatment of the substrate material by multiple printing steps can increase the amount of metal embedded in the material and thus reduce the electrical resistance of the treated material.

[0065] As described above, the methods of the present disclosure advantageously can be carried out at relatively low temperatures because the metal complexing ink compositions used in these methods are converted to elemental metal by curing at relatively low temperatures. The use of low temperatures in these methods thus enables the use of even pyrolyzable substrate materials. Thus, in some embodiments of the disclosed methods, the curing step is carried out at about 300 °C or less, about 250 °C or less, about 200 °C or less, about 150 °C or less, about 100 °C or less, or even lower temperatures.

[0066] The time of the curing step can also advantageously be varied to optimize the results, as would be understood by one of ordinary skill in the art. In particular, the curing step may be carried out over about 120 minutes or less, about 60 minutes or less, about 30 minutes or less, about 20 minutes or less, or even shorter times.

[0067] In another aspect, the present disclosure provides a conductive material, wherein the material is prepared by any of the treatments described herein and in the examples, including those methods described above.

[0068] In yet another aspect, materials and methods as described in the following numbered paragraphs are provided. 1. A conductive material comprising: a textile substrate material; a metal embedded within the textile substrate material; and wherein the metal is embedded within and below the surface of the material. The conductive material, wherein the metal is embedded within and below the surface of the material. 2. The conductive material according to paragraph 1, wherein the textile substrate material is a fabric, fiber, yarn, or thread. 3. The conductive material according to paragraph 2, wherein the fabric, fiber, yarn, or thread is made of a polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material. 4. The fabric substrate material is the conductive material according to paragraph 1, which is a thermally decomposable fabric substrate material. 5. The fabric substrate material is the conductive material according to paragraph 4, which is decomposable at a temperature exceeding about 300 °C. 6. The metal consists of silver, copper, gold, palladium, platinum, or an alloy, or any combination of these metals, which is the conductive material according to paragraph 1. 7. The metal consists of an alloy, or a combination of silver, copper, gold, palladium, or platinum, which is the conductive material according to paragraph 6. 8. The metal consists of silver, which is the conductive material according to paragraph 6. 9. The material is a conductive material prepared by treating a fabric substrate material with a metal complex conductive ink composition. 10. The fabric substrate material is a fabric, fiber, yarn, or thread, which is the conductive material according to paragraph 9. 11. The fabric, fiber, yarn, or thread consists of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material, which is the conductive material according to paragraph 10. 12. The fabric substrate material is a thermally decomposable material, which is the conductive material according to paragraph 9. 13. The fabric substrate material is decomposable at a temperature exceeding about 300 °C, which is the conductive material according to paragraph 12. 14. The metal complex conductive ink composition consists of silver, copper, gold, palladium, or platinum, which is the conductive material according to paragraph 9. 15. The metal complex conductive ink composition consists of a combination of silver, copper, gold, palladium, or platinum, which is the conductive material according to paragraph 14. 16. The metal complex conductive ink composition consists of silver, which is the conductive material according to paragraph 14. 17. The treatment is carried out at a temperature of 300 °C or lower, which is the conductive material according to paragraph 9. 18. The fabric substrate material is treated with a metal complex conductive ink composition by dyeing, which is the conductive material according to paragraph 9. 19. The fabric substrate material is the conductive material described in paragraph 9, which is treated by printing using a metal-complexed conductive ink composition. 20. The material is the conductive material described in any one of paragraphs 1-19, which exhibits an electrical resistance of about 1,000 ohms or less after being stretched by at least about 10%. 21. The material is the conductive material described in paragraph 20, which exhibits an electrical resistance of about 1,000 ohms or less over at least about 100 cycles after being stretched by at least about 10%. 22. A method for preparing a conductive material, comprising providing a fabric substrate material, treating the fabric substrate material with a metal-complexed conductive ink composition, curing the treated substrate material to generate a metal that is embedded within the substrate material. 23. The fabric substrate material is a fabric, fiber, yarn, or thread, as described in paragraph 22. 24. The fabric, fiber, yarn, or thread is made of polyester, polyether-polyurea copolymer, nylon, acrylic, modified cellulose, polyvinyl alcohol, polyvinyl chloride, polyurethane, cotton, wool, linen, or silk material, as described in paragraph 23. 25. The fabric substrate material is a thermally decomposable material, as described in paragraph 22. 26. The fabric substrate material is decomposable at a temperature above about 300 °C, as described in paragraph 25. 27. The metal-complexed conductive ink composition consists of silver, copper, gold, palladium, or platinum, as described in paragraph 22. 28. The metal-complexed conductive ink composition consists of a combination of silver, copper, gold, palladium, or platinum, as described in paragraph 27. 29. The metal-complexed conductive ink composition consists of silver, as described in paragraph 27. 30. The fabric substrate material is treated by dyeing using a metal-complexed conductive ink composition, as described in paragraph 22. 31. The fabric substrate material is treated by printing using the metal-complexed conductive ink composition according to the method described in paragraph 22. 32. The fabric substrate material is treated at least twice using the metal-complexed conductive ink composition according to the method described in paragraph 22. 33. The curing step is carried out at about 300 °C or lower according to the method described in paragraph 22. 34. The curing step is carried out over about 120 minutes or less according to the method described in paragraph 22.

[0069] In the related art, it will be readily apparent to those skilled in the art that other suitable modifications and adaptations to the methods and uses described herein can be made without departing from the scope of the present invention or any of its embodiments. Although the present invention has been described in detail thus far, this is included with this specification for illustrative purposes only and is not intended to be limiting of the present invention. It will be more clearly understood by referring to the following examples.

[0070] (Examples) (Example 1. Printing on a fabric substrate) In a typical embodiment, a silver-complexed ink having suitable rheological properties is screen / stencil printed, dispensed, written using a writing instrument such as a pen or marker, or inkjet printed onto a fabric substrate to form a conductive path. The solid content of the ink typically ranges from about 6% to 50%. Depending on the printing, the ink is impregnated into the fabric and then cured in ambient air at a temperature below 150 °C (typically 140 °C or 100 °C for 20 minutes) over a period of less than 30 minutes. Multiple-pass printing over the same area (e.g., the area corresponding to the desired conductive path) may be required depending on the porosity / absorbency of the fabric. Typical fabrics may be woven, non-woven, knitted, or natural products such as cotton, silk, wool, or linen. Synthetic fabrics include nylon, polyester, polyether-polyurea copolymers (e.g., "Lycra" or "Spandex"), acrylic, modified cellulose (e.g., rayon), acetate, urethane, and the like. The electrical resistance of the resulting conductive fabric may vary depending on the conditions, but will typically be in the range of 5% to 70% of the resistance of bulk metal, e.g., bulk silver.

[0071] Microscopic images (two magnified views) of an exemplary conductive printed fabric prepared according to the above method are shown in FIG. 3. As shown in this image, the fidelity and morphology of the underlying fabric substrate remain intact after the metallization process, indicating that the metal is embedded within the conductive fabric. Such morphology is clearly different from what would be expected for a fabric metallized by conventional processes where a metal trace sitting on top of the fabric would be expected.

[0072] FIG. 4A illustrates typical stretch cycle test data for a conductive fabric prepared by screen printing as described above using the apparatus shown in FIG. 4B and the circuit diagram shown in FIG. 4C. In this example, the fabric was stretched at a 20% stretch ratio over 20 cycles per minute. The resistance of the fabric remained below 10 ohms even after 100,000 cycles.

[0073] Another example of a screen-printed conductive trace on a polyester fabric is illustrated in Table 1 below. The physical and morphological properties of the fabric are illustrated in FIGS. 5A-5B. The conductive fabric cured at 55° C. to 120° C. for 20 minutes exhibits a resistance of less than 1 ohm before and after stretching (Table 1). The macroscopic (FIG. 5A) and microscopic (FIG. 5B) images of the conductive fabric emphasize the normal fabric morphology after metallization. [Table 1]

[0074] (Example 2. Dyeing on Fabric) In a typical example, a silver-complexed ink with suitable rheological properties is contained in a container. A piece of fabric is "pad-dyed" or "dip-coated" into the ink in the container. The typical coating time is about 1 second to 60 minutes, depending on the fabric type. Further, pre-swelling of the fabric can sometimes facilitate better infiltration of the metal-complexed ink into the fabric. Pre-swelling is typically accomplished by exposure of the fabric to a suitable liquid / solvent, in some cases, elevated temperature (e.g., 60° C. to 100° C.), or a combination of both. Once saturated, i.e., "dyed", the fabric is removed and cured in ambient air at a temperature below 150° C. for less than 30 minutes (typically 140° C. or 100° C. for 20 minutes). The solid content of the ink typically ranges from about 6% to 30%. Typical fabrics may be woven or non-woven knitted natural products such as cotton, silk, wool, or linen. Synthetic fabrics may be nylon, polyester, polyether-polyurea copolymers (e.g., "Lycra" or "Spandex"), acrylic, modified cellulose (e.g., rayon), acetate, urethane. The electrical resistance will vary depending on the conditions, but will typically be in the range of 5% to 70% of bulk Ag.

[0075] Exemplary conductive dyed fabrics prepared according to the above method are illustrated in FIGS. 3, 5A, 5B, and 6. The fabric shown in FIG. 6 is further described in Table 2 below. [Table 2]

[0076] (Example 3. Dyeing on Fibers or Yarns) In a typical embodiment, a silver-complexed ink having suitable rheological properties is contained within a container. A single piece of fiber or yarn or multiple fiber / yarn pieces wound together are "pad-dyed" or "dip-coated" into the ink within the container. Typical coating times are from about 1 second to 60 minutes, depending on the fiber or yarn type. Further, the fibers or yarns are sometimes left to pre-swell, which allows for better infiltration of the metal-complexed ink into the fibers or yarns. Pre-swell is typically accomplished by exposure of the fibers or yarns to a suitable liquid / solvent, in some cases, elevated temperatures (e.g., 60 °C to 100 °C), or a combination of both. Once saturated, i.e., "dyed", the fibers or yarns are removed and cured in ambient air at a temperature below 150 °C for less than 30 minutes (typically 140 °C or 100 °C for 20 minutes). The solid content of the ink typically ranges from about 6% to 30%. The electrical resistance will vary depending on the conditions but will typically be within the range of 5% to 70% of bulk Ag.

[0077] Exemplary conductive dyed fibers prepared according to the above method are illustrated in FIG. 7 and further described in Table 3 below. [Table 3]

[0078] (Example 4. Conductive Materials Prepared by Various Printing Methods) Exemplary conductive materials prepared by inkjet or screen printing methods are described in Table 4 below and illustrated in the image shown in FIG. 8. [Table 4]

[0079] (Example 5. Conductive Materials Prepared by Dyeing Fabrics) An additional conductive material prepared by dyeing the fabric is described in Table 5 below and illustrated in the image shown in FIG. 9. [Table 5]

[0080] (Example 6. Conductive Material Prepared by Dyeing Fibers) An additional conductive material prepared by dyeing the fibers is described in Table 6 below and illustrated in the image shown in FIG. 10. [Table 6]

[0081] In all of the above examples, the metal complex ink composition may additionally contain a binder or adhesion promoter to facilitate adhesion to a specific fabric or fiber.

[0082] In all of the above examples, in addition to the advantageous electrical and mechanical (i.e., stretchable) properties of the conductive material, the conductive material modified with a pure silver film, for example, by treatment with a silver complex ink composition, is also essentially antibacterial.

[0083] In all of the above examples, the resistance is typically measured by a two-point resistance measurement over 10 cm.

[0084] All patents, patent publications, and other published references mentioned in this specification are hereby incorporated by reference in their entirety as if each was specifically and individually incorporated by reference.

[0085] Specific embodiments have been provided, but the above description is illustrative and not restrictive. Any one or more of the features of the foregoing embodiments can be combined in any manner with one or more of the features of any other embodiment of the present invention. Further, many variations of the present invention will be apparent to those skilled in the art upon review of the specification. The scope of the present invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents thereto.

Claims

【Claim 1】 The invention described in this specification.

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