WO2017114174A1 - Graphene electrothermal material and application thereof - Google Patents

Abstract

Provided in the present application is a graphene electrothermal material and application thereof. A graphene electrothermal material, mainly composed of graphene, other carbon materials and a solvent, the weight ratio of the graphene and the other carbon materials being 0.5-10:1, preferably 2-10:1, and more preferably 5-10:1, the other carbon materials comprising combinations of one or more of carbon fiber, graphite, and carbon nanotube, and the other carbon materials being preferably carbon fiber. In addition, the graphene electrothermal material provided by the present invention is applied as electrothermal coating of the surface of a substrate. The graphene electrothermal material of the present invention has advantages of being energy-saving, light, excellently flexible, usable in a large area, not prone to oxidization, highly electrically conductive and thermally conductive, and applicable widely, etc.; and can be applied in a plurality of fields, such as clothes-making, human body care, aviation equipment, medical equipment, home heating equipment, and automobile, etc.

Description

Graphene electrothermal material and application thereof

The present application claims the priority of the following Chinese patent application, the entire content of which is hereby incorporated by reference in its entirety in its entirety in its entirety in the the the the the the the the the the Chinese patent application for its application; submitted to China Patent Office on December 31, 2015, application number CN201511033211.6, titled "a graphene adsorption material, its preparation method and its application and cigarette filter" Patent application; Chinese patent application filed on March 4, 2016, China Patent Office, application number CN201610125751.5, entitled "A functional synthetic material and its preparation method, product"; and on May 20, 2016 Submitted to the Chinese Patent Office, the application number is CN201610343555.5, and the Chinese patent application entitled "a PTC inorganic composite material and its preparation method and application".

Technical field

The invention relates to the field of electrothermal materials, in particular to a graphene electrothermal material and an application thereof.

Background technique

With the continuous depletion of non-renewable resources such as coal, oil and natural gas and the increasing environmental pollution, it is particularly urgent and important to research and develop renewable and green clean energy and its supporting industrial and daily necessities. Under the background of solar energy, nuclear power, hydropower and wind power to replace non-renewable resources for heat generation, many industrial products and daily necessities are paying more and more attention to energy conservation and emission reduction. In addition, as people's demand for product portability and wearability increases, low-energy, lightweight and integrated products show great market potential.

As an emerging carbon material, graphene has high electrical and thermal conductivity, and has the advantages of light weight, good flexibility, large-area use, and low oxidation resistance. It has far-infrared radiation performance more prominent than other carbon materials. The components have high somatosensory temperature and good thermal comfort, so graphene has the characteristics of excellent electrothermal materials. However, the energy-saving materials made of graphene on the market are not very good.

In view of this, the present invention has been specifically proposed.

Summary of the invention

A first object of the present invention is to provide a graphene electrothermal material, which has the advantages of light weight, good flexibility, large area use, non-oxidation, high electrical and thermal conductivity, wide application range, and the like. Manufacturing clothing, human care, aviation equipment, medical equipment, household appliances, heating equipment, automobiles and other fields.

A second object of the present invention is to provide an application of the graphene electrothermal material as a substrate surface electrothermal coating which improves the overall electrothermal performance of existing materials.

In one aspect, the present invention provides a graphene electrothermal material, which is mainly composed of graphene, other carbon materials and a solvent, wherein the weight ratio of graphene to other carbon materials is 0.5-10:1, for example, 1:1, 1.5: 1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1 8:1, 8.5:1, 9:1, 9.5:1, etc., preferably 2-10:1, more preferably 5-10:1, and other carbon materials include carbon fiber, graphite, carbon nanotube, carbon crystal In combination with one or more of them, the other carbon material is preferably a carbon fiber prepared from carbon fibers.

Taking carbon fiber as an example, carbon fiber and graphene are both carbon-based materials, and their compatibility and bonding are good, oxidation is not easy, and stability is good. For graphene/carbon fiber mixed slurry, carbon fiber has soft processability, so mixing carbon fiber in a proper ratio can improve the processability of graphene, making it easy to process and easy to form a film structure without reducing it. The thermal conductivity of graphene, on the other hand, synergistically enhances thermal conductivity, which is one of the important differences from the existing graphene electrothermal materials. At the same time, the introduction of carbon fiber can also reduce the cost of graphene electrothermal materials, which can be promoted. Application; the solvent can be selected as a reagent with good solubility, safety, and compatibility, and the dosage is determined according to actual needs. In addition, when the carbon fiber is preliminarily compounded with the substrate, the graphene serves as a slurry to provide a stable conductive support for the adhesion of the slurry.

Similarly, graphene can be mixed with other carbon materials such as graphite and carbon nanotubes to form an electrothermal material.

It is verified that the thermal conductivity of the graphene conductive and thermal conductive layer of the invention can reach 1000 W/m. Above k, the resistivity is 0.5Ω/sq-5Ω/sq, which can work in the lower voltage range (1-5V), which is 50%-70% more energy efficient than the market electric heating film.

The electrocaloric material of the invention is mainly used for heating under low pressure conditions, especially at a high temperature (room temperature to 130 ° C) at 1-5 V. Of course, if the added modifier is reasonable, it can also be used for high pressure heating, for example, household. Voltage 220V (such as for carbon crystal heating plates, see below). There are various application methods, which can be combined on the surface of other materials by printing, knife coating, spraying, dipping, pressing, etc., or can be combined with other materials to form an electric heating film, such as pulp.

In addition, the above electrothermal materials can be used in various fields, and can be applied to heating interlayers for medical and daily household items, as well as for building floor heating, wall heating, greenhouse greenhouses, etc., and also for ships, vehicles, and working in low temperature environments. Deicing of pipelines, instruments, and components such as aircraft.

The above graphene electrothermal material can be further improved:

Preferably, the concentration of the graphene is 2 mg/mL to 200 mg/mL, for example, 10 mg/mL, 20 mg/mL, 30 mg/mL, 40 mg/mL, 50 mg/mL, 60 mg/mL, 70 mg/mL, and 80 mg/mL. 90 mg/mL, 100 mg/mL, 110 mg/mL, 120 mg/mL, 130 mg/mL, 140 mg/mL, 150 mg/mL, 160 mg/mL, 170 mg/mL, 180 mg/mL, 190 mg/mL, and the like.

First of all, such a concentration has sufficient viscosity, low solidity difficulty, and secondly, a high cost performance can be obtained between raw material cost and electrical and thermal conductivity, preferably 50 mg/mL to 200 mg/mL, more preferably 100 mg/mL- 150 mg/mL.

Preferably, the solvent is one or more of water, a hydrophilic solvent. These two solvents are low in cost, safe and harmless, and are suitable for use in a variety of substrates, the hydrophilic solvent including an alcohol solvent, preferably, the alcohol solvent is ethanol.

Preferably, the graphene electrocaloric material further comprises a first dispersing agent, which can improve the dispersibility of the graphene in the solution, and ensure that the cured structure has uniform physical and chemical properties; preferably, the first dispersing agent The agent is one of styrene-maleic anhydride copolyester, polyvinylpyrrolidone, polyoxyethylene ether methacrylate, polyoxyethylene ether acrylate, polyoxypropylene ether acrylate, polyoxypropylene ether methacrylate The mixture or mixture is added in an amount of less than 3% by weight of the solid content of the electrothermal material. The above first dispersant can achieve the effect of allowing the slurry (which may be referred to as "carbon slurry") to be highly concentrated and uniformly dispersed in the aqueous solvent.

Preferably, the graphene electrothermal material further includes a modifier to meet different needs, such as improving electrical conductivity, mechanical properties, and the like.

Preferably, the modifier is selected from one or more of a far infrared finishing agent, an antifoaming agent, and an adhesion promoter;

The far-infrared finishing agent is one or more selected from the group consisting of titanium oxide, zirconium oxide, cerium oxide, zinc oxide, and aluminum oxide, and the amount thereof is less than 1% by weight of the solid content of the electrothermal material. The normal emissivity of the above far infrared finishing agent reaches 0.85 or more, so that the product has more excellent far infrared performance;

The antifoaming agent is selected from one or more of silicone oil, hard fatty acid amide, and aluminum stearate, and is added in an amount of 1% by weight or less based on the solid content of the electrothermal material. The above antifoaming agent can increase the fluidity of the slurry, coat uniformity on the carrier, and improve the heating uniformity of the electrothermal coating.

The adhesion promoter is selected from one or more of aminopropyltrimethoxysilane, polydimethylsiloxane, and biscyclopentadienyl acrylate monomer, and the amount added is 4 wt% of the solid content of the electrothermal material. the following. The above adhesion promoter allows the slurry to adhere more firmly to the carrier.

The graphene of the present invention includes a graphene nanosheet layer and a single layer graphene, a bilayer graphene, a small layer graphene, and further includes a biomass graphene nanosheet layer and biomass graphene.

The graphene of the present invention can be obtained by different preparation methods, such as mechanical stripping method, epitaxial growth method, chemical vapor deposition method, graphite redox method, hydrothermal carbonization method for biomass resources, and prior art. Graphene prepared by other methods. However, it is difficult to achieve large-scale preparation of graphene in a strictly theoretical manner by any method. For example, in the graphene prepared by the prior art, some impurity elements, other allotropes or layers of carbon elements may be present. Non-single or even multi-layered stone The graphene structure (for example, three layers, five layers, ten layers, 20 layers, etc.), and the graphene utilized in the present invention also includes the above-described non-strict theoretical graphene.

A six-membered ring-shaped honeycomb sheet structure with a layer of more than 10 layers and a thickness of 100 nm or less is called a graphene nanosheet layer; a layer prepared by using biomass as a carbon source has more than 10 layers and a thickness of carbon within 100 nm. The six-membered ring-shaped honeycomb sheet structure is called a biomass graphene nanosheet layer; the six-membered loop honeycomb sheet layer structure with a layer number of 1-10 layers of carbon is called graphene; and the biomass is used as a carbon source. The six-membered ring-shaped honeycomb sheet structure having a layer number of 1-10 layers of carbon is called biomass graphene.

Preferably, the graphene is biomass graphene, and the biomass graphene is prepared from biomass. Preferably, the biomass graphene is prepared from biomass-derived cellulose.

Further, the biomass graphene contains a sheet structure of graphene of 10 layers or less, a sp ³ hybrid structure of carbon, and a mineral element; the mineral elements include Fe, Si, and Al elements. The mineral element content is from 0.5% by weight to 6% by weight of the biomass graphene, preferably from 1.5% by weight to 5% by weight. The mineral element preferably further includes any one or more of P, Ca, Na, Ni, Mn, K, Mg, Cr, S, and Co; the mineral element exists as a simple substance and/or a compound, and the compound These include oxides and carbides that are adsorbed on the surface or inside of the biomass graphene. The biomass graphene has a carbon content of ≥ 80 wt%, preferably more than 85 wt%, still more preferably more than 90 wt%, most preferably more than 95 wt%.

Preferably, the biomass is selected from any one or a combination of at least two of agricultural forest waste and/or plants.

Preferably, the plant is any one or a combination of at least two of softwood and/or hardwood.

Preferably, the agricultural and forestry waste is any one or at least two of corn cob, corn cob, sorghum, beet pulp, bagasse, furfural residue, xylose residue, wood chips, cotton stalk, husk, and reed. The combination.

Preferably, the agricultural and forestry waste is a corn cob.

In addition to the above enumeration of biomass, the biomass of the present invention may be any biomass resource known to those skilled in the art, and the present invention will not be further described.

Further, the graphene electrothermal material further includes a PTC inorganic composite material.

Preferably, the PTC inorganic composite material is mainly prepared from 75-95 wt% of nano ceramic material, 1-20 wt% of graphite-based carbon material coating agent, and 0.5-5 wt% of second dispersant, that is, mainly The following raw materials are prepared: 75-95% of the nano ceramic material, 1-20% of the graphite-based carbon material coating agent, and 0.5-5% of the second dispersing agent.

Adding the PTC inorganic composite material of the invention to the graphene electrothermal material can effectively solve the problem of overheating and power loss control of the electrothermal material. The PTC inorganic composite material enables the electrothermal material to have a frequency conversion function. When the temperature gradually reaches the set temperature, the resistance is increased so that the power is appropriately weakened to adjust to a suitable power to control the temperature, thereby greatly saving energy compared with the conventional electrothermal material.

Nano-ceramic materials Compared with other materials with PTC properties, this inorganic type of material can effectively prevent the failure of PTC materials caused by decomposition, gas release and aging.

The graphite-based carbon material coating agent is coated on the outer surface of the ceramic material, the outer surface has good electrical conductivity, has good insulation inside, and can improve far-infrared radiation effect when used as an electric heating material, and is mixed with other carbon materials. Improve the dispersion effect.

The graphite-based carbon material coating agent is a nano-sheet carbon material, and the nano-sheet carbon material has a thickness of 100 nm or less, preferably 50 nm or less, more preferably 30 nm or less, including nano-scale graphite, graphene oxide, and graphene. One or several mixtures, preferably graphene. As an emerging carbon material, graphene itself has high electrical and thermal conductivity, and has the advantages of light weight, good flexibility, large-area use, and low oxidation resistance. It has far-infrared radiation performance more prominent than other carbon materials. The heating element has the characteristics of high somatosensory temperature and good thermal comfort, so it has the characteristics of excellent electrothermal material.

In addition, the sheet structure of graphene is also more favorable for completing the coating of the nano ceramic inorganic material particles, and further improving the dispersibility of the inorganic material and the carbon material. The structure of graphene itself includes a single-layer graphene structure and a multi-layer graphene structure, and may be a six-membered ring-shaped honeycomb layer structure of 1-10 layers of carbon, and may also be a single layer, a double layer or a 3-10 layer. Any combination of any one or more of the structures, it is the graphene having such a lamellar structure that is composite coated with the nanoceramic inorganic material, so that the performance of the ceramic inorganic material is more excellent, and when used in subsequent use Longer life, and the use of graphene to increase the far-infrared ability in subsequent applications, so that heating comfort is further improved, and heating efficiency is improved to indirectly save energy.

The invention fully utilizes the advantages of the nano ceramic material and the graphite-based carbon material coating agent, and the PTC inorganic composite material prepared by using the specific raw material of the invention improves the compatibility of the powder and the graphene electrothermal material on the one hand. It helps to disperse the powder; on the other hand, it makes the surface of such insulator particles have certain conductivity. The inventor has also optimized the optimum addition amount of each raw material through a large number of practices, and the amount of the nano ceramic material is generally 75-95 wt%, and may also be 80-91 wt%, more preferably 85 wt%. It is also possible to select 76 wt%, 77 wt%, 78 wt%, 79 wt%, and 85 wt%, etc. The so-called nano ceramic materials can be directly purchased through the market, and the commercially available materials are semi-finished products, which are subsequently used for the preparation of ceramics, mainly The composition includes one or more of a metal oxide, a non-metal oxide, and a metal boride, and the elements include Ti, Si, Ba, Sn, Cu, Fe, Ag, B, O, and C elements. One or several kinds, of course, if the conditions permit, the nano ceramic material can be prepared by itself. The state of the nano ceramic material is powdery, because the powder shape is favorable for the subsequent uniform formation of a uniform substance with the graphene, and the particle size is preferably controlled. Between 0.1 and 10 μm, it may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or the like. In addition, it should be noted that the nano ceramic material used in the present invention is different from the ordinary ceramic material, and the powder is ultra-fineized by nano-crystallization, so that the surface electronic structure and crystal structure of the ceramic material are changed, and the bulk material is not produced. Special effect Should, for example, significantly reduce the sintering temperature of materials, energy-saving energy, make the composition of ceramic materials densify and homogenize, improve the performance of ceramic materials, improve their reliability, it can be seen that the inventors also have to select each raw material. The specific requirements are not available at will.

The graphite-based carbon material coating agent may be added in an amount of 1 to 20% by weight, may also be 5 to 16% by weight, more preferably 13% by weight, and may also be selected as 2% by weight, 3% by weight, 4% by weight, 6% by weight, 7% by weight, and 8% by weight. 9wt%, etc., the mass ratio of nano-ceramic material to graphite-based carbon material coating agent is controlled to be optimal between (5-9):1, and all aspects of PTC inorganic composite material obtained by compounding under such ratio conditions The performance is superior.

Of course, in order to improve the dispersion performance, in addition to the two main materials of nano ceramic material and graphite carbon material coating agent, a second dispersing agent is added to the raw material to stabilize the dispersed medium, improve the surface properties of the powder, and adjust The action of the kinetic action of the powder enables the graphite-based carbon material coating agent to effectively coat the inorganic material, and the conventional addition amount thereof is 0.5 to 5% by weight, and may also be 1-4% by weight, more preferably 2% by weight, for example, the amount of addition. It may also be 0.7 wt%, 0.9 wt%, 1.2 wt%, 1.4 wt%, 2 wt%, 3 wt%, 4.5 wt%, etc., and the second dispersant is not excessively added as an additive (generally not more than 5 wt%) Therefore, the range of addition also needs to be strictly controlled. The type of the second dispersing agent includes one or more of polyvinyl alcohol, polyethylene glycol, polypropylene glycol, and the second choice of polyvinyl alcohol, the second dispersing agent of the alcohol can substantially satisfy the dispersion in the solution of the present invention. It is not required to use other dispersants such as silanes. These kinds of dispersants are not environmentally friendly, so they are not recommended.

Further, the method for preparing the PTC inorganic composite material comprises the following steps:

After the nano ceramic material is mixed with the graphite-based carbon material coating agent, a second dispersing agent and an appropriate amount of ethanol are added to uniformly obtain a uniform solution, and the heat treatment is performed under an inert gas protection condition of not higher than 200 ° C.

Ethanol acts as a solvent to dissolve and disperse, and is not the main raw material. Therefore, it is not reflected in the formulation of the present invention, and there is no certain requirement for the addition amount, as long as the raw materials can be well integrated into a uniform substance. After the mixing is uniform, the subsequent heat treatment is performed to remove the volatile components in the composite material, the temperature of the heat treatment is controlled below 200 ° C, the better heat treatment temperature is controlled between 80-150 ° C, and the heat treatment time is 40-80 min, mainly It is to achieve the evaporation of the solvent and the second dispersant to be added.

The method of mixing uniformity includes one of ultrasonic, ball milling and agitation. The operating conditions of the ball mill are: the ball milling time is controlled at 2-3 h, the rotation speed is controlled at 400-500 rpm, and the stirring operation condition is: the stirring time is controlled at 30. -40min, the speed is controlled at 700-800rpm, the operating conditions of the ultrasonic are: the ultrasonic power is controlled at 700-900W, and the ultrasonic time is controlled at 60-70min. These three operation modes can be freely selected according to actual operating conditions, as long as they can be realized. The method of mixing the raw materials uniformly can be used.

The graphene electrothermal material containing the PTC inorganic composite material provided by the invention has a good application in the carbon crystal heating plate, and the specific method is to uniformly mix the PTC inorganic composite material and the graphene electrothermal material, and more preferably, the PTC The inorganic composite material is added in an amount of 2 to 5 wt% of the solid content of the graphene electrocaloric material. In this manner, a graphene electrocaloric material having PTC properties and enhanced far-infrared properties can be obtained. Of course, the addition amount of the PTC inorganic composite material is There is a certain limit, not limited to the addition, controlled to 2 to 5 wt% of the solid content of the graphene electrocaloric material, and may also be 3 wt%, 4 wt%, in such a range of carbon crystal heating plate The performance is optimal in all aspects and the service life is also the longest. If the increase of the amount of PTC inorganic composite material is not increased, it will not continue to enhance the performance of graphene electrothermal material, and it will also have the opposite effect. suitable.

Preferably, the graphene electrothermal material is in the form of a plate, a column or a fabric.

The shape of the graphene electrothermal material is mainly determined by its use. For example, when used for making functional fabrics, it is generally fabric-like; when used for household or industrial heating, it is generally columnar, and when used for deicing of mechanical equipment. Generally plate shape. Of course, it can also be designed into any shape according to actual technical requirements or aesthetic requirements.

The above method for preparing the graphene electrothermal material into a sheet/film shape may be: mixing all the raw materials into a slurry according to a formula, then attaching to the carrier according to a preset shape and process, and finally curing or drying. Alternatively, the carbon fiber and the base slurry (mainly referred to as pulp) are firstly made into a paper, and the slurry obtained by mixing the graphene and other auxiliary agents is attached to the substrate according to a preset process, and finally solidified or dried.

In another aspect, the present invention provides the use of the graphene electrothermal material described above as a substrate surface electrothermal coating, which is mainly used for improving the comprehensive electrothermal performance of the material, and the material has the advantages of high electrical and thermal conductivity and wide application range. On the basis of the above, it also has the advantages of light weight, good flexibility, large-area use, and low oxidation resistance.

Preferably, the electrothermal coating further comprises a circuit layer printed on its surface.

The material of this structure is suitable for mass production, that is, printing a plurality of sub-circuits on a large-area graphene conductive heat-conducting layer, and then cutting into small components, and it is easier to achieve quality control. In addition, in order to improve the electrical conductivity of the circuit layer on the graphene layer, it is also possible to add a modifier to improve the dispersion or viscosity of the graphene when the graphene layer is formed.

Preferably, the surface of the electrothermal coating adheres to the phase change material layer, firstly combines the graphene electrothermal material with the phase change material, thereby improving the strength and avoiding the shortcomings, and fully utilizing the advantages of both, the electrothermal material composed has the excellent electrothermal performance of graphene. It also has good heat storage performance. Secondly, the structural relationship of layer stacking is adopted to avoid performance interference between materials.

When the circuit layer is printed on the surface of the electrothermal coating, the printed circuit layer may be directly in contact with the phase change material, or the graphene layer may be in contact with the phase change material, and may be adjusted according to actual conditions.

Preferably, the phase change material layer is made of an inorganic phase change material, an organic phase change material or a polymer phase change material; preferably, the inorganic phase change material is selected from the group consisting of sodium sulfate, sodium acetate, and calcium chloride. One or more of a class of phosphates selected from the group consisting of paraffin waxes, fatty acids or lipids thereof, higher aliphatic hydrocarbons, alcohols, aromatic hydrocarbons, amides, and polyhydroxycarbonic acids. One or more of the polymer phase change materials are one or more selected from the group consisting of polyolefins, polyhydric alcohols, polyalkenols, polyenoic acids, and polyamides.

Among the above materials, the solid-solid phase change material layer has a wider application range, and the solid-liquid phase change material is prevented from being restricted by liquid flow, and the polyol solid-solid phase change material layer is optimal, and the cost is low. .

Preferably, the electrothermal coating layer and the phase change material layer are encapsulated with an insulating material, and the surface of the phase change material layer is encapsulated with an insulating material. The addition of an insulating protective layer is to improve the safety of the electrothermal material for direct use in the human body. The insulating protective layer may be made of a plastic or resin type material, and the insulating material may contain or may be added with an anti-oxidation heat-resistant agent of 1 wt‰-3 wt‰ depending on the application field. Preferably, the anti-oxidation heat-resistant agent is selected from bisphenol. One or more of monoacrylate, 2,5-di-tert-butyl hydroquinone, and distearyl pentaerythritol diphosphite.

Preferably, the surface of the substrate is soldered with a circuit layer. The location of the circuit is generally determined by the application area.

Preferably, the substrate comprises an object or a solid shell that needs to be heated and/or warmed. Preferably, the substrate comprises a fabric, a building, a plastic, a ship, an aircraft, a deicer; the substrate is also based on the material. Depending on the application, the lamination of the layers can be achieved by processes such as printing, knife coating, spraying, dipping and pressing.

In addition, according to the application field of the graphene electrothermal material of the present invention, the method of compounding with other materials is different, generally adopting the following two methods:

Method 1 is mainly for printing a circuit layer on the surface of the graphene layer, comprising the following steps:

Step A: mixing all the raw materials according to the formulation of the graphene conductive heat conductive layer to obtain a graphene slurry;

Step B: impregnating, printing, spraying or pressing the graphene slurry onto the surface of the base layer, and drying to form a graphene layer;

Step C: printing a circuit on the surface of the graphene layer to form a circuit layer;

Step D: impregnating, printing, spraying or pressing the phase change material on the surface of the circuit layer to obtain a product.

Preferably, after impregnating, printing, spraying or pressing the phase change material, the method further comprises encapsulating the insulating thermally conductive layer on the surface of the phase change material.

Preferably, the method of drying in step B is: drying or vacuum drying.

The second method mainly applies to the circuit layer soldering on the substrate, and includes the following steps:

Step I: mixing all the raw materials according to the formulation of the graphene conductive heat conductive layer to obtain a graphene slurry;

Step II: printing a circuit on the surface of the substrate to form a circuit layer;

Step III: impregnating, printing, spraying or pressing the graphene slurry onto the surface of the substrate, and drying to form a graphene layer;

Step IV: impregnating, printing, spraying or pressing the phase change material on the surface of the graphene layer to obtain a product.

Preferably, after the step of forming the graphene layer and before the step of immersing, printing, spraying or pressing the phase change material, the method further comprises: encapsulating the insulating protective layer on the surface of the graphene layer.

Both of the above methods can be realized by conventional mechanical equipment, and the flow is simple, so that mass production can be easily realized.

In another case, the slurry of the graphene electrothermal material is mixed with the base slurry (mainly referred to as pulp) and then solidified into a unitary structure to form an electric heating film; or the carbon fiber is separately combined with the base slurry (mainly referred to as pulp). The mixture is solidified together as a carrier, and then the graphene electrothermal material slurry is impregnated into the substrate and dried to form an electrothermal film.

The above description only describes the preparation method of the graphene electrothermal material derivative, which cannot be exhaustive, and therefore the material of the present invention is not limited to the above application range.

The graphene electrothermal material and the application thereof provided by the invention can bring at least one of the following beneficial effects:

(1) The material is soft and can be processed;

(2) The material has excellent thermal conductivity. The material can be applied to electric heating materials with good temperature uniformity. It is used in electric heating devices, such as heating coating of carbon crystal electric heating plate, the performance is more stable, the temperature is uniform, and there is no aging. Problems such as flatulence, causing subversive improvement of the performance of the electric heating device itself, greatly prolonging the service life, and at the same time bringing considerable economic benefits;

(3) The material has good heat storage performance;

(4) The material energy saving and environmental protection can effectively solve the problem of overheating and power loss control of the electric heating device, and the electric heating device can have the frequency conversion function, that is, when the temperature gradually reaches the set temperature, the electric resistance increases so that the power is appropriately weakened and adjusted to the appropriate power. To control the temperature, which is much more energy efficient than traditional electrothermal materials;

(5) a wide range of materials;

(6) Light and easy to carry;

(7) The material preparation method is simple and suitable for industrial production.

DRAWINGS

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the specific embodiments or the description of the prior art will be briefly described below, and obviously, the attached in the following description The drawings are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

1 is a schematic structural view of a graphene electrothermal material provided in Application Example 1 of the present invention;

2 is a schematic structural view of still another graphene electrothermal material provided in Application Example 1 of the present invention (the insulating heat conductive layer 4 is symmetrically disposed on the lower surface of the base layer 1);

3 is a schematic structural view of still another graphene electrothermal material provided in Application Example 1 of the present invention (the insulating heat conductive layer 4 and the phase change material layer 5 are symmetrically disposed on the lower surface of the base layer 1);

4 is a schematic structural view of an electrothermal material provided in Application Example 2 of the present invention.

Reference mark:

The base layer 1, the electrode 2, the graphene-containing conductive heat conduction 3, the insulating heat conductive layer 4, the phase change material layer 5, the insulating protective layer 6, and the circuit layer 7.

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is to be construed as illustrative only. Those who do not specify the specific conditions in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are conventional products that can be obtained by commercially available purchase.

The biomass graphene of the present invention refers to a graphene prepared by using biomass as a carbon source, and a specific process for preparing graphene using biomass as a carbon source has been reported in the art, and typical but non-limiting examples include CN104724699A. .

In an embodiment of the invention, the biomass graphene can be produced by a biomass resource hydrothermal carbonization process. Specifically, the following are only examples:

method 1:

(1) catalytically treating a biomass carbon source under the action of a catalyst to obtain a precursor;

(2) maintaining the precursor at 140 ° C - 180 ° C for 1.5 h - 2.5 h under protective gas conditions to obtain a first intermediate;

(3) heating the first intermediate to 350 ° C -450 ° C for 3 h - 4 h under protective gas conditions to obtain a second intermediate;

(4) heating the second intermediate to 1100 ° C at 1300 ° C for 2 h - 4 h under a protective gas condition to obtain a third intermediate;

(5) sequentially washing the third intermediate with alkali, pickling, and washing with water to obtain graphene;

The heating rate in the steps (3), (4) is 14 ° C / min - 18 ° C / min.

The biomass graphene prepared in the above method 1 (the graphene prepared in the prior art may have some impurity elements, other allotropes of carbon elements or graphene structures having a non-monolayer or even a plurality of layers, The graphene prepared by the biomass method is also a mixture containing graphene, amorphous carbon and non-carbon non-oxygen elements.

Method 2: The method disclosed in CN104118873A.

Method 3: The method disclosed in CN104016341A.

Method 4: The method disclosed in CN104724696A.

Method 5: Method disclosed in CN104724699A.

Method 6: The method disclosed in CN105060289A.

Method 7:

Follow these steps:

(1) catalytically treating a biomass carbon source under the action of a catalyst to obtain a precursor;

Preferably, the temperature of the catalytic treatment is controlled at 150-200 ° C, time ≥ 4 h, preferably 4-14 h; the moisture content in the precursor is preferably 10 wt% or less; and the temperature of the precursor is raised to 140-180 ° C ° C The rate is preferably 3-5 ° C / min; the protective atmosphere is any one or a combination of nitrogen, helium, argon, preferably nitrogen; the crude washing is followed by pickling and washing; pickling Hydrochloric acid having a concentration of 3 to 6 wt% is preferably used, further preferably hydrochloric acid having a concentration of 5 wt%, and the water washing is preferably carried out using deionized water and/or distilled water, and the washing temperature is controlled to be between 55 and 65 ° C, preferably 60 ° C.

(2) maintaining the precursor at 140 ° C - 180 ° C for 1.5 h - 2.5 h under protective gas conditions to obtain a first intermediate;

In some embodiments of the invention, the temperature is 142 ° C, 148 ° C, 155 ° C, 160 ° C, 172 ° C or 178 ° C, and the holding time is 1.6 h, 1.8 h, 2 h, 2.2 h or 2.4. h.

(3) heating the first intermediate to 350 ° C -450 ° C for 3 h - 4 h under protective gas conditions to obtain a second intermediate;

In some embodiments of the invention, the temperature is 360 ° C, 370 ° C, 380 ° C, 390 ° C, 410 ° C, 420 ° C, 430 ° C or 440 ° C; the holding time is 3.1 h, 3.3 h, 3.5h, 3.8h or 3.9h.

(4) heating the second intermediate to a temperature of 1100 ° C - 1300 ° C for 2 h - 4 h under a protective gas condition to obtain a third intermediate; that is, a crude product.

In some embodiments of the invention, the temperature is 1130 ° C, 1170 ° C, 1210 ° C or 1280 ° C; the time is 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3.0 h, 3.2 h, 3.4 h, 3.6h or 3.8h;

Preferably, the rate of temperature rise in steps (3) and (4) is 14 ° C / min -18 ° C / min, in some embodiments of the invention, the rate of temperature increase is 15 ° C / min, 16 °C/min or 17 °C/min.

(5) The third intermediate (crude product) is sequentially subjected to alkali washing, pickling, and water washing to obtain a composite containing carbon nanostructures; that is, the above-described biomass graphene (composite containing carbon nanostructures) One).

The biomass carbon source in the above step is selected from any one or a combination of plants and/or agricultural and forestry wastes, preferably any one or several of softwood, hardwood, forestwood, and agricultural and forestry waste. Combining; the agricultural and forestry waste is preferably selected from the group consisting of corn cob, corn cob, sorghum, beet pulp, bagasse, furfural residue, xylose residue, wood chips, cotton stalk, husk, and reed. Combination, preferably corn cob. The biomass carbon source is selected from a combination of one or more of lignocellulose, cellulose, lignin, more preferably cellulose and/or lignin, and may also be cellulose, further preferably porous cellulose. The biomass graphene prepared above does not need to be activated or modified.

In the present invention, the biomass carbon source is preferably one or more of lignocellulose, cellulose and lignin, more preferably lignocellulose, cellulose or lignin.

Preferably, the cellulose is a porous cellulose obtained by the following method:

The biomass resources are subjected to acid hydrolysis to obtain lignocellulose, which is then subjected to porous treatment to obtain porous cellulose; alternatively, the porous cellulose is used after being bleached.

The biomass resource is selected from any one or a combination of plants and/or agricultural and forestry waste; preferably any one or combination of agricultural and forestry wastes.

Preferably, the agricultural and forestry waste is selected from the group consisting of corn cob, corn cob, sorghum, beet pulp, bagasse, furfural residue, xylose residue, wood chips, cotton stalks and reeds, preferably Corn cob.

The biomass carbon source of the present invention comprises a combination of corn cob and corn cob, a combination of bagasse, high mast and wood chips, a combination of beet pulp, bagasse and corn cob, a combination of high mast, beet pulp and xylose residue, etc. .

The mass ratio of the biomass carbon source to the catalyst used in the catalytic treatment is preferably 1: (0.5-5), preferably 1: (1-3); in some embodiments of the invention, the ratio is 1: 0.5, 1:1 or 1:3.

The catalyst is selected from the group consisting of a halogen compound of manganese, an iron-containing compound, a cobalt-containing compound, and a nickel-containing compound. The iron-containing compound is selected from the group consisting of a halogen compound of iron, a cyanide of iron, and a ferrite containing one or a combination of several. The ferrite-containing salt is a salt of an organic acid containing an iron element or a salt of an inorganic acid containing an iron element.

The halogen compound of iron may be ferric chloride and/or iron bromide. The cobalt-containing compound is selected from a combination of any one or more of a halogen compound of cobalt and a cobalt-containing acid salt. The cobalt-containing acid salt is a salt of an organic acid containing a cobalt element or a salt of a mineral acid containing a cobalt element. The cobalt halogen compound may be cobalt chloride and/or cobalt bromide. The nickel-containing compound is selected from any one or more of a nickel chloride salt and a nickel-containing acid salt. Combination of species. The nickel-containing acid salt is a salt of an organic acid containing a nickel element or a salt of a mineral acid containing a nickel element. The halogen compound of nickel may be nickel chloride and/or nickel bromide.

Most preferably, the catalyst is selected from the group consisting of iron chloride, ferrous chloride, iron nitrate, ferrous nitrate, iron sulfate, ferrous sulfate, potassium ferricyanide, potassium ferrocyanide, potassium ferric acid trihydrate, A combination of any one or more of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, nickel chloride, nickel nitrate, nickel sulfate, and nickel acetate.

Typical, but non-limiting examples of combinations of catalysts according to the invention are combinations of ferrous chloride and ferric sulfate, combinations of potassium ferricyanide and potassium trioxalate, cobalt chloride, cobalt nitrate and ferric chloride. Combination, a combination of cobalt sulfate, cobalt acetate and nickel nitrate, a combination of ferric chloride, cobalt chloride and nickel acetate.

Preferably, the temperature at which the catalytic treatment is carried out is from 150 ° C to 200 ° C, such as 160 ° C, 170 ° C, 180 ° C, 190 ° C, etc., time ≥ 4 h, preferably 4 h - 14 h, in some embodiments of the invention, time It can be 4.2h, 7h, 9h, 12h, 16h, 19h, 23h.

Preferably, the moisture content in the precursor is controlled to be 10 wt% or less. In some specific embodiments of the invention, the moisture content may also be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt. %, 8 wt%, 10 wt%, and the like.

Preferably, the protective atmosphere is any one or a combination of nitrogen, helium and argon, preferably nitrogen.

Preferably, the pickling uses a hydrochloric acid aqueous solution having a concentration of 3-6 wt%, further preferably a 5 wt% aqueous hydrochloric acid solution; the water washing preferably uses deionized water and/or distilled water; the alkali washing uses a concentration of 5- A 15 wt% aqueous sodium hydroxide solution is further preferably an aqueous sodium hydroxide solution having a concentration of 10% by weight.

The temperature of the final washing is preferably controlled between 55 and 65 ° C, for example, 56 ° C, 57 ° C, 58 ° C, 60 ° C, 63 ° C, etc., preferably 60 ° C.

The percentages of the various modifiers added in the examples below refer to the total amount of the slurry.

Preparation of biomass graphene A1:

(1) mixing corncob cellulose and ferrous chloride according to a mass ratio of 1:1, stirring at 150 ° C for catalytic treatment for 4 h, drying to a precursor moisture content of 10 wt%, to obtain a precursor;

(2) In a N ₂ atmosphere, the precursor was heated to 170 ° C at a rate of 3 ° C / min, kept for 2 h, then programmed to 400 ° C, held for 3 h, then heated to 1200 ° C, after 3 h to obtain a crude product; The heating rate of the heating is 15 ° C / min;

(3) The crude product was acid-washed at a concentration of 10% sodium hydroxide solution and 4 wt% hydrochloric acid at 55-65 ° C, and then washed with water to obtain biomass graphene, which was designated as biomass graphene A1. In the biomass graphene A1, the mineral elements include Fe, Si, and Al elements, and the content is 3 wt% of the biomass graphene A1.

Preparation of biomass graphene A2:

The same method as the above preparation of biomass graphene A1 was used except that the mass ratio of corncob cellulose to ferrous chloride was changed to 0.2:1, and the prepared biomass graphene A2 contained mineral elements including Fe, Si and Al element, and the content is 0.5% by weight of the biomass graphene A2.

Preparation of biomass graphene A3:

Using the same method as the above-described preparation of biomass graphene A1, except that the corncob cellulose was changed to lignocellulose, and the mass ratio to ferrous chloride was changed to 6:1, the prepared biomass graphene A3 was The mineral elements include Fe, Si, and Al elements and are present in an amount of 6 wt% of the biomass graphene A3.

Preparation of biomass graphene B:

Biomass graphene B was prepared by the method of Example 1 in the patent application publication No. CN104724699A.

Graphene C:

The model produced by Changzhou Sixth Element Materials Technology Co., Ltd. is SE1231 conductive and heat conductive graphene.

Preparation of PTC inorganic composite material a:

1) In the nano ceramic material composed of metal oxide, non-metal oxide and metal boride, the molar ratio of each element, Ti is 5-15%, Si is 20-50%, Fe is 1-5%, B 5-10%, O is 50-70%;

2) 75 kg of the above nano ceramic material, 20 kg of nano-scale graphite having a thickness of 100 nm or less, followed by adding 0.5 kg of polyvinyl alcohol and an appropriate amount of ethanol to a solution state, mixing and pulverizing using a cell pulverizer for 30 minutes, and controlling the rotation speed at 800 rpm;

3) After evaporating the ethanol, the obtained product is heat-treated to remove the polyvinyl alcohol, the heat treatment temperature is 200 ° C, the temperature is kept for 30 min, and the whole process is vacuum N ₂ protection;

4) The heat-treated product is sieved to obtain a PTC inorganic composite material, which is referred to as a PTC inorganic composite material a.

Preparation of PTC inorganic composite b:

1) In the nano ceramic material composed of metal oxide and non-metal oxide, the molar ratio of each element, Ba is 10-20%, Ti is 5-30%, Si is 5-10%, Ag is 5-10 %, O is 50-75%;

2) 95 kg of the above nano ceramic material, 10 kg of graphene oxide having a thickness of 50 nm or less, followed by adding 5 kg of polyethylene glycol and an appropriate amount of ethanol to a solution state, ball milling for 2 h using a vacuum ball mill, and rotating at 500 rpm;

3) After evaporating the ethanol, the obtained product is heat-treated to remove the polyethylene glycol, the heat treatment temperature is 150 ° C, the temperature is kept for 40 min, and the whole process is vacuum N ₂ protection;

4) The heat-treated product is sieved to obtain a PTC inorganic composite material, which is referred to as a PTC inorganic composite material b.

Preparation of PTC inorganic composite c:

1) In the nano ceramic material composed of metal oxide, non-metal oxide and metal boride, the molar ratio of each element, Ti is 10-30%, Fe is 5-10%, Si is 10-20%, Cu 5-10%, Sn is 1-5%, O is 50-70%;

2) 80 kg of the above nano ceramic material, 1 kg of graphene having a thickness of 30 nm or less, followed by adding 1 kg of polyethylene glycol and an appropriate amount of ethanol to a solution state, 700 W ultrasonic for 60 min;

3) After evaporating the ethanol, the obtained product is heat-treated to remove the polyethylene glycol, the heat treatment temperature is 150 ° C, the temperature is maintained for 80 min, and the whole process is vacuum N ₂ protection;

4) The heat-treated product is sieved to obtain a PTC inorganic composite material, which is referred to as a PTC inorganic composite material c.

Preparation of PTC inorganic composite d:

1) In the nano ceramic material composed of metal oxide, non-metal oxide and metal boride, the molar ratio of each element, Ti is 10-30%, Fe is 5-10%, Si is 10-20%, Cu 5-10%, Sn is 1-5%, O is 50-70%;

2) 91 kg of the above nano ceramic material, 16 kg of graphene having a thickness of 30 nm or less, followed by adding 4 kg of polyethylene glycol and an appropriate amount of ethanol to a solution state, 900 W ultrasonic for 70 min;

3) After evaporating the ethanol, the obtained product is heat-treated to remove the polyethylene glycol, the heat treatment temperature is 80 ° C, the heat preservation is 60 min, and the whole process is vacuum N ₂ protection;

4) The heat-treated product is sieved to obtain a PTC inorganic composite material, which is referred to as a PTC inorganic composite material d.

Preparation of PTC inorganic composite material e:

1) In the nano ceramic material composed of metal oxide, non-metal oxide and metal boride, the molar ratio of each element, Ti is 10-30%, Fe is 5-10%, Si is 10-20%, Cu 5-10%, Sn is 1-5%, O is 50-70%;

2) 85 kg of the above nano ceramic material, 5 kg of graphene (thickness below 30 nm) and nano-scale graphite, followed by adding 2 kg of polyethylene glycol and appropriate amount of ethanol to a solution state, ball milling for 3 h using a vacuum ball mill, rotating at 400 rpm ;

3) After evaporating the ethanol, the obtained product is heat-treated to remove the polyethylene glycol, the heat treatment temperature is 150 ° C, the heat is kept for 60 min, and the whole process is vacuum N ₂ protection;

4) The heat-treated product is sieved to obtain a PTC inorganic composite material, which is referred to as a PTC inorganic composite material e.

Preparation of PTC inorganic composite material f:

1) In the nano ceramic material composed of metal oxide, non-metal oxide and metal boride, the molar ratio of each element, Ti is 10-30%, Fe is 5-10%, Si is 10-20%, Cu 5-10%, Sn is 1-5%, O is 50-70%;

2) 85 kg of the above-mentioned nano ceramic material, 13 kg of graphene having a thickness of 30 nm or less, followed by adding 2 kg of polyethylene glycol and an appropriate amount of ethanol to a solution state, mixing and pulverizing using a cell pulverizer for 40 min, and controlling the rotation speed at 700 rpm;

3) After evaporating the ethanol, the obtained product is heat-treated to remove the polyethylene glycol, the heat treatment temperature is 150 ° C, the heat is kept for 60 min, and the whole process is vacuum N ₂ protection;

4) The heat-treated product is sieved to obtain a PTC inorganic composite material, which is referred to as a PTC inorganic composite material f.

Example 1:

(1) The ratio of biomass graphene A1 and carbon fiber to a mass ratio of 1.5:1, with 1 wt% (solid content, the same below) styrene-maleic anhydride copolyester, 0.1 wt% silicone oil, and 2 wt% The aminopropyltrimethoxysilane was dissolved in ethanol to obtain a graphene composite slurry having a concentration of 50 mg/mL.

(2) The PTC inorganic composite material a containing 2% by weight of the electrothermal material is uniformly compounded with the above slurry to obtain a graphene electrothermal material carbon slurry.

Example 2

The difference from Example 1 is that the PTC inorganic composite material a is not added.

Example 3

(1) Biomass graphene A1 and carbon fibers were dissolved in ethanol at a mass ratio of 2:1 to obtain a graphene composite slurry having a concentration of 2 mg/mL.

(2) The carbon slurry was sprayed on a 4 cm*4 cm insulating material to form a heating film of 0.1 mm, and sufficiently dried.

(3) The both ends of the dried heating film are pressed and welded with a copper foil strip as an electrode.

Example 4

The difference from the first embodiment is that the mass ratio of the biomass graphene A1 to the other carbon materials (the mass ratio of the carbon fibers, the carbon nanotubes, and the graphite is 5:1:4) in the step (1) is 0.5:1. A certain amount of the first dispersant 1 wt% of polyvinylpyrrolidone, 0.5 wt% of hard fatty acid amide, and 1.3 wt% of biscyclopentadienyl acrylate monomer were dissolved in ethanol to obtain a graphene composite having a concentration of 20 mg/mL. Material slurry.

Example 5

The difference from the embodiment 1 is that the mass ratio of the biomass graphene A1 to the carbon fiber in the step (1) is 5:1, and a certain amount of the first dispersing agent is 3 wt% of polyvinylpyrrolidone and 0.8 wt% of stearin. Aluminum acid, 4 wt% of polyoxypropylene ether acrylate, 3 wt% of titanium oxide and dissolved in ethanol to obtain a graphene composite slurry having a concentration of 150 mg/mL.

Example 6

The difference from the embodiment 1 is that the mass ratio of the biomass graphene A1 to the carbon fiber in the step (1) is 10:1, and a certain amount of the first dispersing agent is 3 wt% of polyvinylpyrrolidone and 0.8 wt% of stearin. Aluminum acid and 4% by weight of polyoxypropylene ether acrylate were dissolved in ethanol to obtain a graphene composite slurry having a concentration of 200 mg/mL.

Example 7-10

The difference from Example 1 is that the biomass graphene A1 in the step (1) is replaced with biomass graphene A2, biomass graphene A3, biomass graphene B, and graphene C, respectively.

Example 11

The difference from the embodiment 1 is that the PTC inorganic composite material b which accounts for 3 wt% of the electrothermal material is added in the step (2).

Example 12

The difference from the embodiment 1 is that the step (2) adds 4 wt% of the PTC inorganic composite material c to the electrothermal material.

Example 13

The difference from the embodiment 1 is that the PTC inorganic composite material d containing 5 wt% of the electrothermal material is added to the step (2).

Example 14

The difference from the embodiment 1 is that the PTC inorganic composite material e containing 2.5 wt% of the electrothermal material is added in the step (2).

Example 15

The difference from the embodiment 1 is that the PTC inorganic composite material f which accounts for 3.5 wt% of the electrocaloric material is added in the step (2).

Control case

The carbon fiber and 1 wt% of a styrene-maleic anhydride copolyester, 0.1 wt% of a silicone oil, and 2 wt% of an aminopropyltrimethoxysilane were dissolved in ethanol to obtain a slurry having a carbon fiber solid content of 5 wt%.

Application example 1

(1) press-welding a copper foil strip as an electrode at both ends of the conductive insulating plastic material, and then spraying the carbon slurry obtained in Example 1 on a conductive insulating plastic material to form a heating film, and coating a heating film on the heating film. The layer of epoxy resin is encapsulated in one package.

(2) Cutting and milling the target, obtaining the solder joints, and sealing the solder joints with insulating materials after wiring.

(3) After laminating a phase change material (sodium acetate) film having a thickness of 0.5 mm outside the heat conductive plastic, the entire secondary package is performed using an insulating layer.

This application example obtains an electric heating film with excellent far-infrared function, good heat storage capacity, energy saving and stable resistance value, which is beneficial to human health and comfort. It can be applied to heating interlayers for medical and daily household items.

The product structure obtained in this application example is as shown in FIG. 1 , and includes a base layer 1 (ie, a fiber fabric), an electrode 2 , a graphene-containing conductive heat conductive layer 3 , an insulating and thermally conductive layer 4 , a phase change material layer 5 , and an insulating protective layer 6 . .

On this basis, the insulating and thermally conductive layer 4 may be symmetrically disposed on the lower surface of the base layer 1, as shown in FIG. 2; or the insulating and thermally conductive layer 4 and the phase change material layer 5 may be symmetrically disposed on the lower surface of the base layer 1, as shown in the figure. 3 is shown.

Application example 2

(1) The heat-resistant pulp and the slurry obtained in Example 1 were composited in a ratio of 1:1 to prepare a heat-resistant conductive paper, and the thickness was adjusted according to actual needs.

(2) Electrodes and wires are printed on the surface of the heat-resistant conductive paper using copper paste (silver paste). Then the heating film is completed.

(3) Selecting a polyol solid-solid phase change material film (pentaerythritol PE) with a suitable phase transition temperature.

(4) Degassing, followed by integral packaging using an insulating layer.

The heating film obtained by the application example is light in weight and good in flexibility, and is suitable for working at a small working voltage, and the working temperature is suitable for the human body to bear. Can be widely used in clothing, body care wearables.

The product structure obtained in this application example is as shown in FIG. 4, and includes a graphene-containing conductive and thermally conductive layer 3, a circuit layer 7, a phase change material layer 5, and an insulating protective layer 6.

Application Example 3

The fiber fabric and the foamed material are sufficiently immersed in the slurry obtained in Example 1, followed by extrusion or filtration, drying, and the like; and then the phase change material (pentaerythritol PE) is sprayed on the surface of the dried graphene layer.

The fiber fabric or the foaming material is applied to the inner surface or the interlayer of the laundry or the filler, respectively, and whether an external circuit can be selected according to actual conditions.

This application example applies the far-infrared radiation performance and bacteriostatic performance of biomass graphene itself, and improves the somatosensory comfort and warmth and warmth performance of clothes, car seats and the like.

The carbon paste obtained in the above embodiments 1-15 can be sprayed on pipelines, instruments and parts of ships, vehicles, aircrafts, etc., and is used for anti-freezing by the purpose of rapid heating of the surface under a small voltage condition, for example, 1-5V. ice. It can also be used for heating coating of carbon heating plate. It can increase the proportion of heat dissipation in the far infrared form by heating, for example, a household voltage of 220V, and play a health care role.

The above embodiments 1-15 are mainly applied to the plate-shaped or fabric-like electrothermal materials, and the interlayer bonding mainly adopts a spraying process, and the pressing process can also be used in actual operation, and a thickener can also be added to reduce the pressing difficulty, and The columnar (ie, wire) material, the sequence of the process, and the additives and conditions added in each step can be referred to the above examples, but the bonding method between each layer is more preferably impregnated, for example, impregnating the graphene layer to In the phase change material, the corresponding liquid can be uniformly attached to the surface of the graphene layer.

Experimental example

For the pastes obtained in Examples 1-15 and Comparative Examples, the following tests were carried out:

The copper foil strip is pressed as an electrode at both ends of the 4cm*4cm fiberglass cloth, and the carbon slurry is sprayed on the fiberglass cloth to form a heating film, and the heating film is coated with a layer of epoxy resin insulation. The glue is packaged to obtain a heating film for testing.

Add 12V voltage across the heated film electrode and place it in a constant temperature 25 ° C windless environment for performance testing. The main test data includes:

(1) The highest temperature of the film after heating for 30 s, recorded as data 1;

(2) The highest temperature of the film after heating for 60 s, recorded as data 2;

(3) The temperature difference between the highest temperature and the lowest temperature of the heating film after heating for 30 s, recorded as data 3;

(4) After reaching the maximum temperature, the temperature difference between the highest temperature of the same temperature measurement point and the lowest temperature of the falling temperature is recorded as data 4.

Table 1 test results

	Data 1/°C		Data 2/°C		Data 3/°C		Data 4/°C
Example 1	90	90	2	7
Example 2	90	110	2.5	No fall
Example 3	55	63	1	No fall
Example 4	70	69	1	4
Example 5	120	122	2.5	10
Example 6	150	148	3	10
Example 7	88	90	2	6
Example 8	90	91	1	8
Example 9	89	90	2	6
Example 10	93	91	12	7
Example 11	88	88	1.5	5
Example 12	87	87	2	4

Example 13	88	88	2	3
Example 14	88	89	1.5	6.5
Example 15	88	90	2	4
Control case	75	100	45	No fall

It can be seen from the comparison between Example 1 and Example 2 that the carbon slurry to which the PTC material is added in the first embodiment can lower the temperature by increasing the electric resistance in the high temperature stage, and the control temperature should not be too high. And through Examples 11-13, it is found that as the amount of PTC material added increases, the oscillation range of the maximum temperature and the falling temperature decreases, and the subsequent process is generally stable, precisely because the material of the present invention has sufficient temperature stability. Sexuality, which greatly extends the life of the material itself in subsequent use.

By comparison, the temperature unevenness of the comparative example in which the graphene was not added was significantly higher, and the electrothermal radiation conversion efficiency was relatively low.

Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims (20)

1. A graphene electrothermal material, which is mainly composed of graphene, other carbon materials and a solvent, wherein the weight ratio of graphene to other carbon materials is 0.5-10:1, and other carbon materials include carbon fiber, graphite, carbon nanometer. One or a combination of tubes.
2. The graphene electrocaloric material according to claim 1, wherein the graphene is biomass graphene.
3. The graphene electrocaloric material according to claim 2, wherein the biomass graphene contains a mineral element, and the mineral element comprises an element of Fe, Si, and Al.
4. The graphene electrocaloric material according to claim 3, wherein the content of the mineral element is from 0.5% by weight to 6% by weight of the biomass graphene.
5. The graphene electrocaloric material according to claim 3, wherein the mineral element further comprises any one or more of P, Ca, Na, Ni, Mn, K, Mg, Cr, S, and Co.
6. The graphene electrocaloric material according to claim 1, wherein the graphene has a concentration of from 2 mg/mL to 200 mg/mL, preferably from 50 mg/mL to 200 mg/mL, more preferably from 100 mg/mL to 150 mg/ mL.
7. The graphene electrocaloric material according to claim 1, wherein the solvent is one or more kinds of water and a hydrophilic solvent;

   Preferably, the hydrophilic solvent comprises an alcohol solvent, and the alcohol solvent is preferably ethanol;

   Preferably, the weight ratio of the graphene to other carbon materials is 2-10:1, more preferably 5-10:1;

   Preferably, the other carbon material is carbon fiber, more preferably carbon crystal prepared by using carbon fiber.
8. The graphene electrothermal material according to claim 1, further comprising a first dispersing agent;

   Preferably, the first dispersing agent is styrene-maleic anhydride copolyester, polyvinylpyrrolidone, polyoxyethylene ether methacrylate, polyoxyethylene ether acrylate, polyoxypropylene ether acrylate, polyoxypropylene One or more of the ether methacrylates are mixed.
9. The graphene electrothermal material according to claim 1, further comprising a modifier;

   Preferably, the modifier is one or more of a far infrared finishing agent, an antifoaming agent, and an adhesion promoter.
10. The graphene electrothermal material according to claim 8, further comprising a modifier;

    Preferably, the modifier is one or more of a far infrared finishing agent, an antifoaming agent, and an adhesion promoter.
11. The graphene electrocaloric material according to claim 9, wherein the far-infrared finishing agent is one or more selected from the group consisting of titanium oxide, zirconium oxide, cerium oxide, zinc oxide, and aluminum oxide. The foaming agent is selected from one or more of silicone oil, hard fatty acid amide, aluminum stearate, and the adhesion promoter is selected from the group consisting of aminopropyltrimethoxysilane, polydimethylsiloxane, and dicyclopentanyl acrylate. One or more of the ester monomers.
12. The graphene electrothermal material according to any one of claims 1 to 11, further comprising a PTC inorganic composite material;

    Preferably, the PTC inorganic composite material is mainly prepared from 75-95 wt% of a nano ceramic material, 1-20 wt% of a graphite-based carbon material coating agent, and 0.5-5 wt% of a second dispersant;

    Further preferably, the PTC inorganic composite material is mainly prepared by 80-91 wt% nano ceramic material, 5-16 wt% graphite-based carbon material coating agent, and 1-4 wt% second dispersing agent;

    More preferably, the PTC inorganic composite material is mainly prepared from 85 wt% of a nano ceramic material, 13 wt% of a graphite-based carbon material coating agent, and 2 wt% of a second dispersant.
13. The graphene electrothermal material according to claim 12, wherein the nanoceramic material is mainly composed of one or more of a metal oxide, a non-metal oxide, and a metal boride;

    Preferably, the nano ceramic material has a particle size controlled between 0.1 and 10 μm.
14. The graphene electrocaloric material according to claim 13, wherein the element contained in the nanoceramic material comprises one of Ti, Si, Ba, Sn, Cu, Fe, Ag, B, O, and C elements. Species or several

    Preferably, the second dispersing agent comprises one or more of polyvinyl alcohol, polyethylene glycol, and polypropylene glycol;

    The graphite-based carbon material coating agent is a nano-sheet carbon material, and the nano-sheet carbon material has a thickness of 100 nm or less, preferably 50 nm or less, more preferably 30 nm or less, and includes nano-scale graphite and graphene oxide. , a mixture of one or more of graphene.
15. The graphene electrocaloric material according to claim 13 or 14, wherein the method for preparing the PTC inorganic composite material comprises the following steps:

    After mixing the nano ceramic material with the graphite carbon material coating agent, adding a second dispersing agent and an appropriate amount of ethanol to uniformly obtain a uniform solution, and heat treatment under an inert gas protection condition of not higher than 200 ° C;

    Preferably, the temperature of the heat treatment is controlled at 80 to 150 ° C for 40 to 80 minutes.
16. The graphene electrocaloric material according to claim 15, wherein the method of adding a second dispersing agent and an appropriate amount of ethanol and mixing uniformly comprises one of ultrasonic, ball milling and stirring;

    Preferably, the ball milling time is controlled at 2-3 h, and the rotation speed is controlled at 400-500 rpm;

    Preferably, the stirring time is controlled at 30-40 min, and the rotation speed is controlled at 700-800 rpm;

    Preferably, the power of the ultrasound is controlled at 700-900 W and the time of ultrasound is controlled at 60-70 min.
17. The graphene electrocaloric material according to claim 13, 14 or 16, wherein the PTC inorganic composite material is added in an amount of 2 to 5% by weight based on the solid content of the graphene electrocaloric material.
18. Use of the graphene electrocaloric material of any of claims 1-17 as a substrate surface electrothermal coating.
19. The use according to claim 18, wherein said electrothermal coating further comprises a circuit layer printed on its surface;

    Preferably, the electrothermal coating surface is attached with a phase change material layer, and preferably, the phase change material layer is made of an inorganic phase change material, an organic phase change material or a polymer phase change material;

    Preferably, the inorganic phase change material is selected from one or more of sodium sulfate, sodium acetate, calcium chloride, and phosphate, and the organic phase change material is selected from the group consisting of paraffin, fatty acid or fat thereof. One or more of a class, a higher aliphatic hydrocarbon, an alcohol, an aromatic hydrocarbon, an amide, and a polyhydroxycarbonic acid, the polymeric phase change material being selected from the group consisting of polyolefins, polyhydric alcohols, and polyenols. One or more of a class, a polyenoic acid, and a polyamide;

    Preferably, the electrothermal coating layer and the phase change material layer are encapsulated with an insulating material, and a surface of the phase change material layer is encapsulated with an insulating material;

    Preferably, the insulating material contains 1 wt% to 3 wt% of an antioxidant heat resistant agent;

    Preferably, the anti-oxygen heat-resistant agent is one or more selected from the group consisting of bisphenol monoacrylate, 2,5-di-tert-butyl hydroquinone, and distearyl pentaerythritol diphosphite.
20. The use according to claim 18 or 19, wherein the substrate comprises an object that needs to be heated;

    Preferably, the substrate comprises a fabric, a building, a plastic, a ship, an aircraft, a de-icing vehicle;

    Preferably, the composite method of the substrate and the electrothermal coating is selected from the group consisting of printing, knife coating, spraying, dipping, and pressing.

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