阅读说明：本技术 一种可穿戴加热器及其制备方法 (Wearable heater and preparation method thereof ) 是由 拜永孝 陈相平 于 2021-08-30 设计创作，主要内容包括：本发明提供了一种可穿戴加热器及其制备方法。该可穿戴加热器是一种对称“三明治”结构的石墨烯基电热织物,其结构包括石墨烯发热层和设置在其两表面的TPU层,TPU层的外表面均设置有织物基底,石墨烯发热层是由高导电性石墨烯油墨层和其两端设置的柔性电极带所构成,电极与外部电源相连接构成导电通路,可实现低电压发热,在3V电压下即可达到适宜人体的温度。本发明的TPU/织物具有较高的拉伸强度,使得本发明的可穿戴加热器具有高弹性、可愈合柔性,即便在发生较大变形时仍能够保证正常工作,并大大降低出现裂纹的可能性,而且制备工艺简单、可操控性强、容易实现规模化生产等优点。(The invention provides a wearable heater and a preparation method thereof. This wearable heater is the graphite alkene base electric heat fabric of a symmetry "sandwich" structure, and its structure includes that graphite alkene generates heat the layer and sets up the TPU layer at its two surfaces, and the surface on TPU layer all is provided with the fabric basement, and graphite alkene generates heat the layer and comprises the flexible electrode area that high conductivity graphite alkene ink layer and its both ends set up, and the electrode is connected with external power source and constitutes electrically conductive path, can realize that the low-voltage generates heat, can reach suitable human temperature under 3V voltage. The TPU/fabric has high tensile strength, so that the wearable heater has high elasticity and healing flexibility, can still ensure normal work even when large deformation occurs, greatly reduces the possibility of cracks, and has the advantages of simple preparation process, strong controllability, easy realization of large-scale production and the like.)

1. A wearable heater, characterized by: the graphene heating fabric comprises a graphene heating layer (1) and TPU layers (2) arranged on two surfaces of the graphene heating layer, wherein fabric substrates (3) are arranged on the outer surfaces of the TPU layers (2).

2. A wearable heater according to claim 1, wherein: the fabric substrate comprises any one of polyester fiber, spandex and chinlon.

3. A method of making a wearable heater according to any of claims 1-2, wherein: the method comprises the following steps:

s1, hot-pressing the TPU layer on the fabric substrate to form two TPU/fabric structures;

s2, printing high-conductivity graphene ink on the inner surface of the TPU/fabric structure obtained in the step S1 to obtain a high-conductivity graphene ink layer;

s3, bonding flexible electrode strips at two ends of the high-conductivity graphene ink layer prepared in the step S2 to form the graphene heating layer;

s4, hot-pressing the other TPU/fabric structure on the graphene heating layer obtained in the step S3 to obtain the wearable heater.

4. The method of manufacturing a wearable heater according to claim 3, wherein: in step S1, the process parameters of the first hot pressing include: the pressure is 1.5 to 2.5Kgf/m²The temperature is as follows: 140-180 ℃ and 15-30 s.

5. The method of manufacturing a wearable heater according to claim 4, wherein: in step S2, the highly conductive graphene ink includes the following components in parts by mass: 60-80 parts of graphene slurry, 0.5-8 parts of a binder, 0.2-1.8 parts of a leveling agent, 5-15 parts of a viscosity regulator and 0.2-1 part of a defoaming agent.

6. The method of manufacturing a wearable heater according to claim 5, wherein: in step S2, the binder includes any one of polyurethane, acrylic acid, and acrylic acid/TPU, the leveling agent includes polyacrylate or urea-formaldehyde resin, the viscosity modifier includes any one of ethylene glycol, isopropyl alcohol, and diethylene glycol, and the defoamer includes a W530-silicon defoamer or a JT-908 defoamer.

7. The method of manufacturing a wearable heater according to claim 6, wherein: in step S2, the printing mode is single-sided printing with a screen printer, and the number of times of the single-sided printing is 4-8.

8. The method of manufacturing a wearable heater according to claim 7, wherein: in step S3, the flexible electrode tape is a double-sided conductive copper foil tape.

9. The method of manufacturing a wearable heater according to claim 8, wherein: in step S4, the process parameters of the second hot pressing include: comprises a pressure of 1.5 to 2.5Kgf/m²The temperature is as follows: 140-180 ℃ and 30-60 s.

Technical Field

The invention relates to the technical field of flexible wearable conductive fabrics, in particular to a wearable heater and a preparation method thereof.

Background

Flexible electrothermal heaters are gaining attention in wearable electronics for their widespread use, including thermal garments, physiotherapy devices, medical equipment, and bending heaters for vehicles. Among conventional electrocaloric materials, Indium Tin Oxide (ITO) is widely used due to its high transparency and high conductivity. However, indium has high cost, ITO has slow thermal response speed, high brittleness and low strength, and is not suitable for flexible application. Over the last decade, a number of potential alternative materials for ITO have been investigated, which can be divided into two basic categories: metal materials and carbon materials. The metal thin film heater can operate at a low voltage, however, this type of heater requires expensive noble metals such as gold (Au) and silver (Ag) as raw materials. In addition, metal nanowire junctions have the disadvantage of being susceptible to oxidation or failure at high temperatures, which greatly limits their widespread use. Carbon Fiber Paper (CFP) is widely used as a flexible film heater because of its ease of handling, low cost, and high heat generation efficiency. However, the long carbon fibers with high surface energy in the carbon fiber paper make this type of heater opaque and the heat generation temperature non-uniform. Graphene is low in cost, light in weight, and has a high thermal conductivity, and its remarkable thermal conductivity ensures that the graphene-based heater can provide a fast response and a uniform temperature distribution. In addition, the two-dimensional hexagonal conjugated structure endows graphene with good mechanical bending performance. Therefore, graphene has great application advantages in flexible heaters.

The common graphene-based flexible wearable heater is single in performance and only has a heating function. In the prior art, a fabric is generally directly used as a substrate, and graphene conductive slurry is attached to the surface of the fabric layer by means of spraying, blade coating or dipping. However, the fabric is a three-dimensional network structure formed by weaving yarns in the warp and weft directions, the surface roughness of the fabric is large, graphene ink is directly coated on the surface of the fabric, a two-dimensional graphene nanosheet is difficult to form a conductive path, a large amount of ink is often required to be attached to the surface of the fabric to form the conductive path, the cost is high, and the flexibility of the fabric is greatly influenced.

In practical application, the electrothermal fabric in the prior art may crack or break when exposed to stretching, twisting, bending, folding, cutting and other acting forces, so that a conductive path is broken, the heating performance and the service life of the electrothermal fabric are remarkably reduced or even fail, and the electrothermal fabric cannot be repaired after being damaged. The problems are hopefully solved by reasonably designing the preparation process.

Disclosure of Invention

The present invention is directed to a wearable heater and a method for manufacturing the same, which overcome the above-mentioned shortcomings of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a wearable heater which comprises a graphene heating layer and TPU layers arranged on two surfaces of the graphene heating layer, wherein fabric substrates are arranged on the outer surfaces of the TPU layers.

Further, the fabric substrate includes any one of polyester fiber, spandex and nylon.

The invention also provides a preparation method of the wearable heater, which comprises the following steps:

step S1, hot pressing the TPU layer on the fabric substrate to form two TPU/fabric structures;

step S2, printing high-conductivity graphene ink on the inner surface of the TPU/fabric structure obtained in step S1 to obtain a high-conductivity graphene ink layer;

step S3, bonding flexible electrode strips at two ends of the high-conductivity graphene ink layer prepared in the step S2 to form the graphene heating layer;

and step S4, hot-pressing another TPU/fabric structure on the graphene heating layer obtained in the step S3 to obtain the wearable heater.

Further, the hot pressing in step S1 has process parameters including a pressure of 1.5 to 2.5Kgf/m²The temperature is as follows: 140-180 ℃ and 15-30 s.

Further, in step S2, the highly conductive graphene ink includes the following components in parts by mass: 60-80% of graphene slurry, 0.5-8% of binder, 0.2-1.8% of flatting agent, 5-15% of viscosity regulator and 0.2-1% of defoaming agent.

Further, in step S2, the binder is any one of a mixed solution of polyurethane, acrylic acid, and TPU, the leveling agent is polyacrylate or urea resin, the viscosity modifier is any one of ethylene glycol, isopropyl alcohol, and diethylene glycol, and the defoamer is a W530-silicon defoamer or a JT-908 defoamer.

Further, in step S2, the printing mode is single-sided printing with a screen printer, and the number of times of the single-sided printing is 4-8.

Further, in step S3, the flexible electrode tape is a double-sided conductive copper foil tape.

Further, the second hot pressing in step S4 has process parameters including a pressure of 1.5 to 2.5Kgf/m²The temperature is as follows: 140-180 ℃ and 30-60 s.

The technical scheme provided by the invention has the beneficial effects that:

(1) the invention provides a wearable heater, which is a graphene-based electric heating fabric with a symmetrical sandwich structure. The graphene heating layer is composed of a high-conductivity graphene ink layer and flexible electrode strips arranged at two ends of the graphene ink layer, and is connected with an external power supply through electrodes to form a conductive path, so that low-voltage heating can be realized, and the temperature suitable for a human body can be reached under 3V voltage.

(2) The wearable heater provided by the invention adopts high-conductivity graphene ink, and has stable low-voltage heating performance and higher response speed through screen printing. The TPU/fabric has higher tensile strength, so that the wearable heater has high elasticity and healing flexibility, can still ensure normal work even when large deformation occurs, and greatly reduces the possibility of cracks. When the device is subjected to lasting or overlarge tension, cracks or fractures may be generated, the damaged device is placed in hot-pressing equipment due to the characteristic that the TPU layer is sticky at high temperature, the TPU layer is re-bonded under hot pressing, the graphene nanosheets inside the TPU layer are re-bonded, the heating layer recovers a conductive loop, the mechanical property of the heater can be repaired, the low-voltage heating property of the heater can be recovered, and the healing performance can be realized. Due to the regular sandwich structure and the protection effect of the TPU layer, the heater also has the advantages of good water washing performance, severe environment resistance (such as high temperature exposure/low temperature resistance) and the like.

(3) The method provided by the invention also has the advantages of simple preparation process, strong controllability, easiness in realizing large-scale production and the like.

Drawings

Fig. 1 is a schematic structural diagram of a wearable heater provided by the present invention.

1. A graphene heating layer; 2. a TPU layer; 3. a fabric substrate.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be further described with reference to the accompanying drawings and examples.

The high elasticity of the present invention means: the graphene-based flexible wearable heater works normally under 0-400% strain (tensile, bending) and has good recoverability.

The healing property of the invention means that: when the strain is more than 400 percent (under the conditions of stretching and bending), the high-elasticity graphene-based flexible wearable heater can heal the microcracks/fractures, and the heater is arranged at 1.5-2.5 Kgf/m²Under the condition of pressure and temperature of 140-180 ℃, after hot pressing for 15-30 s, the product can be healed and the performance is recovered.

The TPU in the present invention refers to a thermoplastic polyurethane elastomer rubber.

Example 1:

step S1, the TPU layer and the nylon fabric substrate are placed at 1.5Kgf/m²Two TPU/fabric structures were made after hot pressing for 15s under pressure at 140 ℃.

Step S2, preparing a highly conductive graphene ink: 0.5 part of binder, 0.2 part of leveling agent, 5 parts of viscosity regulator and 0.2 part of defoaming agent are added into graphene slurry with the solid content of 260 mg/mL. Mechanically stirring for 4 hours to uniformly mix the materials to prepare the high-conductivity graphene ink with the viscosity of 180mpa & s;

wherein the binder is polyurethane, the flatting agent is polyacrylate, the viscosity regulator is ethylene glycol, and the defoaming agent is a W530-silicon defoaming agent;

and (4) printing high-conductivity graphene ink on the inner surface of the TPU/fabric structure obtained in the step (S1), wherein the number of single-side printing is 5, and drying is carried out for 10min at 50 ℃ to obtain a high-conductivity graphene ink layer.

And step S3, bonding flexible electrode strips at two ends of the high-conductivity graphene ink layer to obtain a graphene heating layer.

And step S4, hot-pressing a TPU layer of another TPU/fabric on the graphene heating layer in the step S3 to prepare and form the wearable heater.

Example 2:

step S1, the TPU layer and the polyester fabric substrate are placed at 2Kgf/m²Two TPU/fabric structures were made after hot pressing for 30s under pressure at 180 ℃.

Step S2, preparing a highly conductive graphene ink: 8 parts of a binder, 1 part of a leveling agent, 10 parts of a viscosity regulator and 1 part of a defoaming agent are added into graphene slurry with the solid content of 260 mg/mL. Mechanically stirring for 4 hours to uniformly mix the materials to obtain the high-conductivity graphene ink with the viscosity of 200mpa & s;

wherein, the binder is acrylic acid, the flatting agent is urea-formaldehyde resin, the viscosity regulator is diethylene glycol, and the defoaming agent is JT-908 defoaming agent;

and (4) printing high-conductivity graphene ink on the inner surface of the TPU/fabric structure obtained in the step (S1), wherein the number of single-side printing is 8, and drying is carried out for 10min at 50 ℃ to obtain a high-conductivity graphene ink layer.

Step S3, bonding flexible electrode strips to both ends of the highly conductive graphene ink layer; and obtaining the graphene heating layer.

And step S4, hot-pressing a TPU layer of another TPU/fabric on the graphene heating layer in the step S3 to prepare and form the wearable heater.

Example 3:

step S1, the TPU layer and the polyester fabric substrate are placed at 2.5Kgf/m²And (3) hot pressing for 30s under the conditions of pressure and temperature of 180 ℃ to obtain the TPU/fabric structure.

Step S2, preparing a highly conductive graphene ink: 6 parts of a binder, 1.8 parts of a leveling agent, 15 parts of a viscosity regulator and 0.8 part of a defoaming agent are added into graphene slurry with the solid content of 280 mg/mL. Mechanically stirring for 4 hours to uniformly mix the materials to obtain the high-conductivity graphene ink with the viscosity of 250mpa & s;

wherein the binder is a mixed solution of acrylic acid and TPU, the flatting agent is polyacrylic acid, the viscosity regulator is isopropanol, and the defoamer is JT-908 defoamer;

and (4) printing high-conductivity graphene ink on the inner surface of the TPU/fabric structure obtained in the step (S1), wherein the number of single-side printing is 6, and drying is carried out for 10min at 50 ℃ to obtain a high-conductivity graphene ink layer.

Step S3, bonding flexible electrode strips to both ends of the highly conductive graphene ink layer; and obtaining the graphene heating layer.

Step S4, hot-pressing a TPU layer of another TPU/fabric on the graphene heating layer in the step S3 to prepare and form the wearable heater;

comparative example 1:

step S1, adding 0.5 part by mass of a binder, 0.2 part by mass of a leveling agent, 15 parts by mass of a viscosity regulator and 0.2 part by mass of an antifoaming agent into the graphene slurry with the solid content of 280 mg/mL. And mechanically stirring for 4 hours to uniformly mix the materials to obtain the high-conductivity graphene ink with the viscosity of 250mpa & s.

Wherein, the adhesive is acrylic acid, the flatting agent is polyacrylic acid, the viscosity regulator is ethylene glycol, and the defoaming agent is JT-908 defoaming agent.

And step S2, printing high-conductivity graphene ink on the surface of the polyester fabric, printing the high-conductivity graphene ink on a single surface for 4 cycles, drying the printed high-conductivity graphene ink for 10min at 50 ℃, and bonding flexible electrode strips at two ends of the surface of the printed high-conductivity graphene ink.

Comparative example 2:

step S1, adding 0.5 part by mass of a binder, 0.2 part by mass of a leveling agent, 15 parts by mass of a viscosity regulator and 0.2 part by mass of an antifoaming agent into the graphene slurry with the solid content of 280 mg/mL. And mechanically stirring for 4 hours to uniformly mix the materials to obtain the high-conductivity graphene ink with the viscosity of 250mpa & s.

Wherein, the adhesive is acrylic acid, the flatting agent is polyacrylic acid, the viscosity regulator is ethylene glycol, and the defoaming agent is JT-908 defoaming agent.

And step S2, printing the high-conductivity graphene ink on the surface of the polyester fabric, printing 4 cycles on a single surface, drying at 50 ℃ for 10min, printing 4 cycles of the graphene conductive ink on the other side of the polyester fabric, drying at 50 ℃ for 10min, and bonding flexible electrode belts at two ends of the fabric.

As shown in fig. 1, the wearable heater prepared by the invention is a graphene-based electric heating fabric with a symmetrical sandwich structure, and the structure of the wearable heater comprises a graphene heating layer 1 and TPU layers 2 arranged on two surfaces of the graphene heating layer, wherein fabric substrates 3 are arranged on the outer surfaces of the TPU layers 2.

The performance of the wearable heaters prepared in examples 1 to 3 and comparative examples 1 to 2 was tested, and the results are shown in table 1:

table 1: performance comparison table

As can be seen from the above table, the electric heating fabric prepared by directly screen-printing the graphene conductive ink on the fabric has the advantages that the graphene nanosheets are coated on the surface of the fabric and penetrate into the internal structure of the fabric to form a conductive path, the fabric fibers wrapped by the graphene nanosheets play a supporting role, and after the graphene conductive ink is cured, the fabric with high elasticity originally loses part of characteristics of the fabric. When the fabric is under great pulling force, the condition that partial graphene falls off exists, the conductive path is disconnected, the local part does not generate heat, the heating temperature is reduced under the same voltage, and the graphene nanosheets are attached to the surface of the fabric fiber and directly drive the fiber to generate heat, so that the aging speed of the electric heating fabric can be accelerated. The high-elasticity graphene-based flexible wearable heater capable of healing designed by the invention has extremely high tensile strength under the protection action of the TPU layer, can still ensure excellent low-voltage heating performance under large tensile force, and has constant heating temperature when the tensile force is removed.

After being washed for 20 times, compared with the electric heating fabric prepared by directly screen-printing graphene conductive ink on the fabric, the wearable heater prepared by the invention can still keep the excellent low-voltage heating performance.

The electrothermal fabrics prepared in the above examples all exhibited microcracks/fractures when exposed to 450% tensile strain for 1min, while the healable high elasticity graphene-based flexible wearable heater we designed was placed in the heater at 2.5Kgf/m²Under the conditions of pressure and temperature of 180 ℃, after hot pressing for 30s, the device is healed, the performance is recovered, and the original excellent low-voltage heating performance is still maintained.

The features of the embodiments and embodiments described herein above may be combined with each other without conflict.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.