JP6736573B2 - Conductive textile element and method of making the same - Google Patents

Description

The present invention relates to the field of electrically conductive textile elements and methods of making the same.

With the rapid development of flexible and wearable electronic devices, there is a need for conductors as interconnects, contacts, electrodes and metal wires that can be incorporated into conductive textiles/garments. Thus synthesizing processed high performance conductive textiles including, or incorporating, yarns made from metal wires, metal oxides, conductive polymers (ICPs) and carbon nanotubes (CNTs). Methods have been developed.
However, the conductive textiles produced by these existing methods are inflexible, chemically unstable, costly to produce, dangerous to the human body, and most importantly, to the current textile and garment industries. It is not ideal due to the challenges associated with large-scale production requiring adaptable technology.

Another approach to synthesizing conductive textiles involves depositing metal coatings on textile substrate surfaces utilizing various metal particle deposition methods. However, in terms of the relative amount of technology investment, sophisticated instrumentation, and expertise of the professional employees involved, and the relatively strict control parameters required, which commercially limit the industrialization of the method. Therefore, there are also limitations associated with this approach.
Moreover, the deposition of deposited metal on textile surfaces leaves another major concern regarding the durability and conductivity of such conductive textiles.

Further, methods have also been developed that include modifying the surface structure of textile substrates by grafting a functionalized polymer brush onto the textile substrate. In particular, polyelectrolytes that are covalently linked to one end of the textile substrate surface can not only result in modification of the functional groups on the textile substrate surface, but also increase the amount of functional groups available for subsequent chemical reactions. You can increase.
As an example, Azzaroni et al. demonstrate the grafting of positively charged poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PMETAC) polyelectrolytes onto a substrate surface. By introducing tetrachloropalladium(II) acid anion ([PdCl ₄ ] ²⁻ ), which is a catalyst portion for electroless plating (ELD) of the metal thereafter, a robust metal layer is selected with appropriate adhesion characteristics. Can be deposited in a static manner.
In 2010, Liu et al. also reported versatility to make durable conductive cotton yarns by growing PMETAC brushes on cotton fiber surfaces using surface-initiated atom transfer radical polymerization (SI-ATRP). Has been reported for the first time, which was the first ever demonstration of grafting a PMETAC brush on a raw textile fiber. Subsequent metal ELDs resulted in conductive cotton yarns with high electrical stability that could withstand multiple flexes, stretches, rubs and even wash cycles.
However, the feasibility of scale production of the SI-ATRP process taught by Liu et al. has various problems. For example, SI-ATRP cannot be performed properly under ambient conditions and requires nitrogen protection. Moreover, the SI-ATRP reaction requires a relatively long time (about 24 hours), which is undesirable and not cost effective for mass production. Therefore, there is a need to improve the synthesis process to enable the production of high throughput conductive textiles.

Another approach has been to conduct conductive fibers, yarns by depositing metal on various textile substrates that have been pre-modified with similar positively charged polyelectrolytes PMETAC using in-situ free radical polymerization. And fabrics to improve the synthetic approach. In-situ free radical polymerization can increase the throughput of polyelectrolyte polymerization.
In general, this reaction takes only about 1 to 3 hours to complete and can be carried out at ambient conditions, which is a great advantage over other polymerization methods such as SI-ATRP mentioned above. Can be said. However, this improved approach has been shown to use cationic PMETACs for the subsequent electroless plating of metals, since the choice of catalyst moieties depends heavily on the properties and properties of the polyelectrolyte brushes grafted onto the textile surface. It has the drawback of being limited by its association with the anionic [PdCl ₄ ] ^2- moiety of
Furthermore, the [PdCl ₄ ] ^2- moiety used is relatively expensive (USD 159.5 per 2 grams of 97% ammonium tetrachloropalladium(II)ate). Anionic [PdCl _4] ^2- portion even can be reused, still not economical when used in mass production.

The present invention seeks to mitigate at least one of the above mentioned problems.

The present invention can include several broad forms. Embodiments of the invention can include one or any combination of the various broad forms described herein.

In a first broad form, the invention comprises:
(I) modifying the surface of the textile element with a negatively charged polyelectrolyte;
(Ii) coating the modified surface of the textile element with metal particles,
There is provided a method of manufacturing a conductive textile element, comprising:

Preferably, step (i) can include modifying the surface of the textile element with a negatively charged polyelectrolyte by in-situ free radical polymerization.

Preferably, the negatively charged polyelectrolyte may include at least one of poly(sodium methacrylic acid salt) and poly(sodium acrylate salt).

Preferably, step (i) can include modifying the silanized surface of the textile element with a negatively charged polyelectrolyte.

Preferably, step (ii) can comprise coating the modified surface of said textile element with metal particles by electroless plating of metal.

Preferably, the metal particles may include at least one of copper and nickel particles.

Preferably, the textile element may include at least one of yarns and fibers configured to form into a fabric.

Preferably, the textile element may comprise at least one of polyester, nylon, cotton and silk threads or fibers.

In a broader form, the invention comprises
A device for modifying the surface of the textile element with a negatively charged polyelectrolyte;
A coating device for coating the modified surface of the textile element with metal particles,
An apparatus for manufacturing an electrically conductive textile element is provided.

Preferably, the apparatus for modifying the surface of the textile element with the negatively charged polyelectrolyte modifies the surface of the textile element with the negatively charged polyelectrolyte by in-situ free radical polymerization. Can be configured to.

Preferably, the negatively charged polyelectrolyte may include at least one of poly(sodium methacrylic acid salt) and poly(sodium acrylate salt).

Preferably, the apparatus for modifying the surface of the textile element with the negatively charged polyelectrolyte is configured to modify the silanized surface of the textile element with the negatively charged polyelectrolyte. You can

Preferably, the coating apparatus can be configured to coat the modified surface of the textile element with metal particles by electroless plating of metal.

Preferably, the metal particles may include at least one of copper and nickel particles.

Preferably, the textile element may include at least one of yarns and fibers configured to form into a fabric.

Preferably, the textile element may comprise at least one of polyester, nylon, cotton and silk threads or fibers.

In a more broad form, the present invention provides a conductive textile element made by the steps of the method of the first broad form of the present invention.

In a more broad form, the invention provides a fabric formed from at least one textile element produced by the steps of the method of the first broad form of the invention.

The present invention will be more fully understood from the following detailed description of preferred, but non-limiting embodiments of the invention, described in connection with the accompanying drawings.

FIG. 3 is a schematic view of a method of making conductive cotton yarn by in-situ free radical polymerization according to an embodiment of the present invention. FIG. 2 illustrates an exemplary copper-coated cotton thread made according to the method shown in FIG. 1. FIG. 4 is a Fourier Transform Infrared Spectroscopy (FTIR) spectral data of pristine cotton yarn, silane modified cotton, and PMANAn modified cotton yarn formed in accordance with an embodiment of the present invention. FIG. 6 is an EDX spectrum of PMANA-modified cotton made according to an embodiment of the present invention. Various modifications including (A) pristine cotton; (B) silane-modified cotton; (C) PMANa-coated cotton; (DF) copper-coated cotton, according to embodiments of the present invention. 6 is a SEM image showing the surface morphology of cotton fibers with quality. FIG. 3 shows data representing (A) linear resistance of as-synthesized copper-coated cotton yarns, and (B) tensile strength of cotton yarns made in accordance with embodiments of the present invention. FIG. 5 shows process steps involved in making a woven fabric formed from copper-coated yarns made in accordance with embodiments of the present invention. FIG. 6 shows sheet resistance data for fabrics woven from copper-coated yarns made in accordance with embodiments of the present invention. 6 is an SEM image of cotton yarn unraveled from a cloth washed under various numbers of washes, the cotton yarn being made according to an embodiment of the present invention. FIG. 3 shows a PMANa-assisted nickel-coated cotton fabric made according to an embodiment of the present invention. FIG. 6 illustrates an exemplary PAANa-assisted copper-coated yarn formed in accordance with an embodiment of the invention. FIG. 3 illustrates an exemplary PAANa-assisted nickel-coated silk yarn formed in accordance with an embodiment of the present invention. FIG. 1 shows a PAANa-assisted copper-coated nylon yarn made in accordance with an embodiment of the present invention and supplemented with PAANa. FIG. 1 shows a polyester fabric formed from PAANa-assisted copper-coated nylon yarn, made in accordance with an embodiment of the present invention, which is PAANa-supplemented copper-coated nylon yarn.

Exemplary embodiments of the present invention will now be described with reference to Figures 1-12B.

Referring first to FIG. 1, there is schematically shown a procedure for making a PMANa polyelectrolyte on a textile substrate such as cotton thread. The present embodiment includes an in-situ free radical polymerization method that can be carried out on a cotton yarn as an example of producing a cotton yarn coated with poly(sodium methacrylic acid salt) (PMANA).
Subsequent ion exchange, ion reduction, and electroless plating of metal particles onto the PMANA-coated cotton yarn are then carried out in order to obtain a conductive cotton yarn of suitable quality for commercial scale production. Good. Note that this embodiment may also be applicable to the preparation of PAAAn polyelectrolytes on textile substrates.

In carrying out this process, cotton yarns are first exposed to 5% to 20% (v/v) silane solution with C=C bonds for approximately 30 minutes to convert the hydroxyl groups of the cellulose into silane molecules. React appropriately.
The cotton thread is then rinsed thoroughly with fresh deionized (DI) water to remove any excess physisorbed silane and by-product molecules. This step of silane treatment is represented by 100 in FIG.

The rinsed cotton yarn is then placed in a 100° C. to 120° C. oven for approximately 15 minutes to 30 minutes to complete the condensation reaction. Subsequently, the silane-modified cotton, is immersed in an aqueous solution of approximately 50mL and a _K 2 _S 2 _{O 8} in MANa powder and 35mg~75mg of 3G～7g (Similarly, the AANa powder for PAANa polyelectrolyte Can be used).
The entire solution mixture containing the cotton thread is heated in an oven at 60°C to 80°C for 0.5 hours to 1 hour in order to carry out free radical polymerization. In the free radical polymerization process, the double bonds of the silane can be cleaved by free radicals, resulting in the growth of PMANa polyelectrolytes on the cotton fiber surface. This step of free radical polymerization is represented by 110 in FIG.

Then, the cotton yarn coated with PMANA is dipped in a 39 g/L copper(II) sulfate pentahydrate solution for 0.5 hours to 1 hour. Here, Cu ²⁺ ions are fixed on the polymer by ion exchange. Subsequent reduction in 0.1 M to 1.0 M sodium borohydride solution reduces Cu ²⁺ to Cu particles that act as nucleation sites for Cu growth in subsequent Cu electroless plating. It is thought to be. This step of ion exchange and reduction is represented by 120 in FIG.

12 g/L sodium hydroxide, 13 g/L copper(II) sulphate pentahydrate dissolved in water, polymer-coated cotton after reduction in sodium borohydride solution, 29 g/L It is immersed for 60 minutes to 180 minutes in a copper electroless plating bath consisting of sodium potassium tartrate and 9.5 mL/L of formaldehyde. The as-synthesized Cu-coated yarn is rinsed with deionized (DI) water and air dried.
The step of performing electroless plating of metal is represented by 130 in FIG. 1, and an exemplary Cu-coated cotton thread made according to the steps of the method of this first embodiment is represented by 200 in FIG. expressed.

Silane modified cotton and PMANa grafted cotton can be characterized by Fourier Transform Infrared Spectroscopy (FTIR). As shown in FIG. 3, the presence of additional peaks located at 1602 cm ⁻¹ and 1410 cm ⁻¹ represents the C═C bond of the silane molecule. Another characteristic peak located at 769 cm ⁻¹ is attributed to the symmetrical stretching of Si—O—Si, which indicates that the silane molecules can cross-link each other on the cotton fiber surface.
In the PMANA-modified cotton sample, a new peak located at 1549 cm ⁻¹ , which represents the antisymmetric stretching vibration of the carboxylate, confirms the PMANA-graft. The other peaks located at 1455 cm ⁻¹ and 1411 cm ⁻¹ both belong to the symmetrical stretching vibration of the carboxylate by PMANA.

PMANA-grafted cotton can also be characterized by energy dispersive X-ray analysis (EDX). It is shown in FIG. 4 that the polymerization of MANa leaves a cotton sample with elemental sodium indicating the presence of PMANA. With further reference to the scanning electron microscopy (SEM) image of FIG. 5, it can be seen that there is no apparent difference between the morphology on the surface of the silanized cotton fiber surface and the untreated cotton fiber surface. Can be said to be clear.
However, it is noteworthy that the coating layer covers the cotton fiber surface after polymerization of PMANA on the silane-treated cotton fiber surface. 5D-F show that the copper metal particles are deposited relatively uniformly without any sign of cracking.

The conductivity of copper coated cotton yarns can be characterized by two-probe electrical inspection. In this regard, the linear resistance of the as-manufactured copper clad yarn was found to be about 1.4 Ω/cm as shown in FIG. 6A and as shown in FIG. 6B. Is superior to untreated cotton yarn, and both tensile elongation (+33.6%) and maximum load (+27.3%) are increased. It is observed that the increase in tensile elongation and maximum load is due to the increased strength of the cotton yarn due to the copper layer.

To further test the copper adhesion and wash durability on the cotton yarn surface, the copper-coated cotton yarn is first woven into a fabric. The as-synthesized copper-coated cotton yarn shown in FIG. 7A is first wrapped around a cone using an industrial yarn winder as shown in FIG. 7B. The cone is then transferred to the CCI loom shown in FIG. 7C to weave the copper coated yarn into a fabric.
In the weave setting, the copper-coated cotton yarns are configured to form the weft yarns of the fabric, while the warp yarns of the fabric are as shown in the inset image of Figure 7D, which was originally mounted on the loom. Formed by untreated cotton yarn. The main weaving process has no problems or drawbacks.
After weaving, the fabric was cut into 5 cm x 15 cm sections and sewn on all sides as shown in Figure 7D, followed by test standard AATCC Test Method 61-Test No. 2A under the following wash conditions: ( Color fastness to home and commercial) laundry: A series of wash cycles according to (machine wash) accelerated (FIG. 7E).

Note that according to test standards, one wash cycle equals approximately five commercial machine wash cycles. A total of 6 wash cycles are performed, and accordingly this is considered to correspond to approximately 30 commercial machine wash cycles.
Since the change in the electric resistance of the washed cloth can be evaluated by using the four-point probe method, the sheet resistance of the cloth manufactured according to this embodiment is 0.9±0 as shown in FIG. .2 ohms/sq (unwashed) and 73.8±13.4 ohms/sq after 4 washes, which is approximately equal to 20 commercial machine wash cycles.

The surface morphology of the washed copper-coated cotton yarn characterizes the washed copper-coated cotton yarn unraveled from the fabric and can be tested by SEM. As shown in the SEM image of Figure 9, it is visibly apparent that the copper metal particles are retained on the surface of the cotton fibers. One recognized reason for the increased sheet resistance is due to the loose structure of the cotton fibers created by repeated washing cycles.

Also note the addition of 50 steel balls to the washing canisters in order to explore the simulation of the strong friction and stretching forces of the laundry machine while applying the standard washing cycle to the fabrics made. To do. The friction of the steel balls on the fabric has a great effect on the fiber structure.
The copper-coated cotton fibers no longer stay tight and lose contact with each other, resulting in a reduction of the conductive pathways available for electron transfer. Therefore, the SEM image in FIG. 9 confirms the relatively strong adhesion of the copper metal particles on the cotton fiber surface, despite increasing sheet resistance with repeated wash cycles.

In an alternative embodiment of the invention, instead of coating the cotton fibers with copper particles, nickel metal particles may instead be electrolessly plated onto the textile surface using the same approach as above. The same experimental procedure and tests may be carried out, but the source of nickel available is a 120 g/L solution of nickel(II) sulphate in the ion exchange method.
Subsequently, it consists of 40 g/L nickel sulfate hexahydrate dissolved in water, 20 g/L sodium citrate, 10 g/L lactic acid, and 1 g/L dimethylamine borane (DMAB). A nickel electroless plating bath is used for 60 minutes to 180 minutes. It can be seen that the sheet resistance of the resulting nickel-coated cotton fabric shows results very similar to those of the copper-coated fiber yarn, as shown in FIG.
Referring to FIG. 10, an exemplary nickel-coated cotton cloth is represented by 300, which exhibits high nickel metal uniformity, and its bulk resistance is measured to be 3.2Ω.

It is understood that other embodiments of the invention may include the use of substrates other than cotton and may also be suitable applied to various textile materials such as silk, nylon and polyester. See.
In this regard, an exemplary PAANa-assisted copper-coated yarn made according to embodiments of the present invention (PAANa-assisted copper-coated yarn) is represented by 400 in FIG. An exemplary PAANa-assisted nickel-coated silk yarn made according to the invention is represented by 500 in FIG. 11B and made according to an embodiment of the invention. A PAANa-assisted copper-coated nylon yarn is represented by 600 in FIG. 12A and is made in accordance with an embodiment of the present invention. The polyester fabric formed from PAANa-assisted copper-coated nylon yarn is represented by 700 in FIG. 12B.

From the above summary, which is a broad form of the invention, advantageously manufacture conductive textile elements that may exhibit suitable flexibility, wearability, durability and/or washability for incorporation into textiles/fabrics. It will be appreciated that various advantages may be provided, including what can be done.
It should be noted that such high performance conductive textile elements (fibers, threads and fabrics) can be manufactured cost-effectively and on a large scale, using relatively low cost techniques. The preparation involves growing a negatively charged polyelectrolyte, such as PMANA or PAANAa, on a textile substrate by a chemical reaction of in-situ free radical polymerization, which advantageously produces an electroless plated metal. , Which can result in an improved negatively charged polyelectrolyte layer that crosslinks with textile elements and substrates.
In particular, the deposition of conductive metals on textile substrates can be greatly improved by such surface modification of the layer of negatively charged polyelectrolyte PMANA or PAANa. Here, the electrical performance of such conductive textiles may be more reliable, robust and durable, even after repeated cycles of rubbing, stretching and washing. Also, the in-situ free radical polymerization method used to prepare negatively charged polyelectrolytes can be carried out under ambient and aqueous conditions without the use of any strong chemicals.

Those skilled in the art will appreciate that the invention described herein can be modified and altered other than as specifically described without departing from the scope of the invention. All such variations and modifications apparent to those skilled in the art are to be considered within the spirit and scope of the invention, as broadly described above.
The present invention should be understood to include all such variations and modifications. The invention also includes all of the steps and features mentioned or shown individually or collectively herein and in any and all combinations of two or more of the above steps or features.

Any reference in this specification to any prior art is not an admission that it is forming part of the common general knowledge, or is in any way implied, and is to be construed as such. Should not be.

Claims (14)

A method of manufacturing a conductive textile , comprising:
(I) silanizing the surface of the textile to provide a silanized surface;
By (i i) in-situ free radical polymerization, on the silane treated surface, the step of grafting a negatively charged polyelectrolyte,
(Iii) adding metal ions to the polymer electrolyte by ion exchange,
(Iv) a step of reducing the metal ions to form an elemental metal;
( V ) coating the textile with metal particles,
A method of making a conductive textile , comprising: The method of claim 1 , wherein the negatively charged polyelectrolyte comprises at least one of poly(methacrylic acid sodium salt) and poly(acrylic acid sodium salt). 3. The method of claim 1 or 2 , wherein step ( v ) comprises coating the textile with metal particles by electroless plating of metal. Wherein the metal particles comprise at least one of copper and nickel particles A method according to any one of claims 1-3. The method of any one of claims 1 to 5 , wherein the textile comprises at least one of yarns and fibers configured to form into a fabric. The textile, polyester, nylon, including cotton and at least one of silk threads or fibers, the method according to any one of claims 1-5. A device for manufacturing conductive textiles , comprising:
An apparatus for silanizing the surface of the textile and providing a silanized surface,
a device for grafting a negatively charged polyelectrolyte onto the silanized surface by in-situ free radical polymerization ;
A device for adding metal ions to the polymer electrolyte by ion exchange,
A device for reducing the metal ions to form an elemental metal,
A device for coating the textile with metal particles,
An apparatus for manufacturing a conductive textile, comprising: 8. The device of claim 7 , wherein the negatively charged polyelectrolyte comprises at least one of poly(methacrylic acid sodium salt) and poly(acrylic acid sodium salt). 9. A device according to claim 7 or 8 , wherein the coating device is arranged to coat the textile with metal particles by electroless plating of metal. Wherein the metal particles comprise at least one of copper and nickel particles, apparatus according to any one of claims 7-9. The device according to any one of claims 8 to 10 , wherein the textile comprises at least one of yarns and fibers adapted to be formed into a fabric. The Te key style, polyester, nylon, comprising at least one of cotton and silk threads or fibers, according to any of claims 7-11. Conductive textile produced by the process of the method according to any one of claims 1-6. Fabric formed from at least one textile produced by the process of the method according to any one of claims 1-6.