Intelligent temperature control graphene-based conductive paste and preparation method and application thereof

Abstract

The invention relates to the technical field of conductive paste, and provides intelligent temperature control graphene-based conductive paste and a preparation method and application thereof. According to the invention, the thermal resistance agent is added into the conductive slurry, so that the effect of automatic temperature control can be achieved, the electrically-induced heating flexible device is always kept within a certain temperature range, and the safety problem of the electrically-induced heating flexible device is solved. The intelligent temperature-control graphene-based conductive paste provided by the invention is good in safety, a printed matter printed by using the intelligent temperature-control graphene-based conductive paste cannot generate an overheating phenomenon, the dispersion stability is good, the off-network property is good during printing, large-size and large-scale integrated printing can be realized, and an obtained printed coating has good stretchability, electric conductivity and heat conductivity; the method has a wide application prospect in the field of electrically-induced heating flexible devices.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive pastes, and in particular to an intelligent temperature-controlled graphene-based conductive paste and a preparation method and application thereof. Background Art

[0002] Conductive paste is a mixture composed of solvent, conductive filler, binder and additive, etc. According to the type of conductive filler, conductive paste can be divided into three categories: metal series, carbon series and polymer series. Metal conductive paste mainly includes pastes with Au, Ag, Cu, Al and other fillers. Gold powder has good conductivity and oxidation resistance, but its high cost limits its application. Silver paste is the most widely used metal paste at present. It has good conductivity and is not easy to oxidize, but it has problems such as high cost, low silver content and insufficient electromigration. Copper and aluminum nanoparticles or nanowires have excellent conductivity, but they are easily oxidized, which seriously affects the stability of conductivity. In addition, metal nanoparticles generally need to be sintered or reduced after printing to improve conductivity, which increases the complexity of the process and has high requirements on the performance of the substrate. Polymer conductive paste is a type of paste with conductive polymer as filler. Common conductive polymers include polypyrrole, polythiophene, polyaniline and its derivatives. This type of conductive paste has poor conductivity and long-term stability. Carbon conductive paste is a paste filled with carbon black, graphite, carbon nanotubes, graphene or a mixture of the above. Carbon black has poor conductivity and cannot meet the demand for low resistance. Carbon nanotubes and graphene have similar structures and have excellent electrical properties, high specific surface area, chemical stability and mechanical strength. However, carbon nanotubes are difficult to print electronic flexible devices and have poor off-grid performance. Graphene has excellent performance and is the best candidate for conductive filler to replace metal particles and conductive polymers.

[0003] Electrothermal flexible devices are flexible materials that use the thermal effect of electric current to generate heat energy. They are widely used in various fields that require heating, such as heating equipment, physical therapy equipment, etc. At present, electrothermal flexible devices usually include a flexible substrate and a printed circuit arranged on the flexible substrate. The conductivity of the graphene-based conductive paste printed circuit is stable, but as the power-on time increases, the graphene fabric will cause overheating when heated for a long time. Overheating will not only affect the performance of the graphene fabric, but in severe cases it may also burn the flexible substrate, posing certain safety hazards. Summary of the invention

[0004] In view of this, the present invention provides an intelligent temperature-controlled graphene-based conductive paste and a preparation method and application thereof. The present invention adds a thermal resistor to the graphene conductive paste to achieve intelligent temperature control, avoid overheating, and improve the safety of electrically heated flexible devices.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] An intelligent temperature-controlled graphene-based conductive paste, the components of which include a basic conductive paste and a thermal resistor; in parts by weight, the basic conductive paste includes: 5 to 50 parts of resin, 10 to 50 parts of conductive polymer, 1 to 2 parts of curing agent, and 5 to 30 parts of graphene;

[0007] The thermal resistor is an alkyl carbon chain compound and / or an inorganic phase change material; the mass of the alkyl carbon chain compound is 0 to 20% of the mass of the basic conductive paste, the mass of the inorganic phase change material is 0 to 30% of the mass of the basic conductive paste, and the addition amount of the alkyl carbon chain compound and the inorganic phase change material is not 0 at the same time.

[0008] Preferably, the alkyl carbon chain compound is a paraffin substance; and the inorganic phase change material is a perovskite structure compound.

[0009] Preferably, the paraffin-based substance includes one or more of liquid paraffin, polyethylene wax and oxidized polyethylene wax; the perovskite structure compound is titanate;

[0010] Preferably, the titanate includes one or more of barium titanate, strontium titanate and barium titanate doped with a rare earth element.

[0011] Preferably, the paraffin-like substance is used in the form of an aqueous wax emulsion; the solid content of the aqueous wax emulsion is 20-30%; the mass of the aqueous wax emulsion is 5-20% of the mass of the basic conductive paste.

[0012] Preferably, the conductive polymer includes one or more of polypyrrole, polythiophene, polythiophene derivatives, polyaniline and polyaniline derivatives.

[0013] Preferably, the curing agent is an aliphatic amine curing agent;

[0014] The resin is water-based epoxy resin and / or water-based polyurethane.

[0015] The present invention also provides a method for preparing the intelligent temperature-controlled graphene-based conductive slurry described in the above scheme, comprising the following steps:

[0016] first mixing the resin, the conductive polymer and the curing agent to obtain a mixture;

[0017] The mixed material and graphene are mixed for the second time to obtain a basic conductive paste;

[0018] The basic conductive paste and the thermal resistor are mixed for the third time to obtain the intelligent temperature-controlling graphene-based conductive paste.

[0019] Preferably, the rotation speed of the first mixing is 500-600 r / min; the rotation speed of the second mixing is 300-900 r / min; and the rotation speed of the third mixing is 500-1200 r / min.

[0020] The present invention also provides the use of the intelligent temperature-controlling graphene-based conductive paste described in the above scheme or the intelligent temperature-controlling graphene-based conductive paste prepared by the preparation method described in the above scheme in an electrothermal flexible device.

[0021] The present invention also provides an electrothermal flexible device, comprising a flexible substrate and a conductive layer printed on the surface of the flexible substrate; the conductive layer is formed by printing the intelligent temperature-controlling graphene-based conductive paste described in the above scheme or the intelligent temperature-controlling graphene-based conductive paste prepared by the preparation method described in the above scheme.

[0022] The present invention provides an intelligent temperature-controlled graphene-based conductive paste, the components of which include a basic conductive paste and a thermal resistor; the basic conductive paste includes: 5 to 50 parts of resin, 10 to 50 parts of conductive polymer, 1 to 2 parts of curing agent, and 5 to 30 parts of graphene; the thermal resistor is an alkyl carbon chain compound or an inorganic phase change material; the mass of the alkyl carbon chain compound is 0 to 20% of the mass of the basic conductive paste, the mass of the inorganic phase change material is 0 to 30% of the mass of the basic conductive paste, and the addition amount of the alkyl carbon chain compound and the inorganic phase change material is not 0 at the same time. A thermal resistor refers to a chemical substance with good thermal insulation performance, which can be used to isolate or reduce heat transfer. The working principle is similar to that of conductor resistance, that is, the scattering and dissipation mechanism of some medium molecules and heat subs is introduced into the medium, so that the heat conduction speed in the medium is reduced, so as to achieve the purpose of controlling heat transfer. The present invention adopts an alkyl carbon chain compound or an inorganic phase change material as a thermal resistor, which can play a certain blocking role on the heat transfer medium, and at the same time forms a thermal insulation layer on the surface, so that the heat energy cannot diffuse at will. The intelligent temperature-controlling graphene-based conductive paste provided by the present invention is used as a printed layer on the surface of a flexible substrate. When the electrically heated flexible device reaches a certain temperature, the thermal resistance of the conductive layer will increase, which will have a certain blocking effect on the heat transfer medium, so that the heat energy cannot diffuse at will, thereby slowing down the accumulation of heat and achieving a temperature control effect, so that the electrically heated device is always kept within a certain temperature range, thus effectively solving the safety problem of the electrically heated flexible device. In addition, the thermal resistance agent used in the present invention has the characteristics of low viscosity, high melting point, excellent chemical stability and waterproofness, etc., which can make the conductive paste adhere to the fabric more evenly, achieve a good temperature control purpose, and at the same time improve the softness and service life of the fabric.

[0023] In addition, graphene itself is easy to aggregate, which can easily lead to poor dispersion and stability of the slurry. The present invention uses graphene and conductive polymers together, and through high-speed shear mixing, the graphene and the conductive polymer form an "island-bridge" structure (wherein the "island" is graphene and the "bridge" is a conductive polymer), thereby improving the stability of the slurry. At the same time, the present invention adds a small amount of curing agent to the slurry, and the curing agent can increase the viscosity of the resin, thereby improving the dispersion stability of the graphene and meeting the printing requirements. The intelligent temperature-controlled graphene-based conductive slurry provided by the present invention has good dispersion stability, good off-grid performance during printing, and can be formed in one step.

[0024] The present invention also provides the application of the intelligent temperature-controlled graphene-based conductive paste described in the above scheme in an electrically heated flexible device. The electrically heated flexible device is prepared using the intelligent temperature-controlled graphene-based conductive paste of the present invention, and the device has good safety and will not overheat. The conductive filler used in the conductive paste of the present invention is graphene, which is the material with the highest thermal conductivity so far and has very good thermal conductivity. The total conversion rate of effective electric heat energy is over 99%. At the same time, the special superconductivity ensures the stability of the heating performance. When the graphene is energized, the carbon molecules therein collide and rub violently, thereby causing Brownian motion to generate heat energy, which is then radiated uniformly in a planar manner by controlling the far-infrared rays. The far-infrared light waves released by the graphene are consistent with the human body's own far-infrared spectrum. It is closer, concentrated between 6 and 14μm, and is known as the light wave of life. It can transmit energy at the same frequency and resonate with the human body. When it acts on the human body, it will cause resonance of cell atoms and molecules, be absorbed by the human body, dilate local blood vessels, and accelerate blood circulation. It is more efficient and safer for the human body. The far-infrared light waves released by graphene itself also have a therapeutic effect, which can relieve symptoms such as neuralgia and insomnia, and have a good alleviating effect on diseases such as lumbar muscle strain, lumbar disc herniation, and rheumatoid arthritis. It also has skin care and beauty, promotes detoxification, smoothes the skin, improves the circulatory system, promotes cell growth, increases cell vitality, strengthens liver function, eliminates excess free radicals, improves immune function, and enhances metabolism.

[0025] In addition, the intelligent temperature-controlled graphene-based conductive paste provided by the present invention can realize large-scale, large-scale integrated printing, and no organic solvent volatilization occurs during the printing process, which is environmentally friendly, and the conductive paste itself has no radiation and no magnetic field loop, which is beneficial to human health; and the intelligent temperature-controlled graphene-based conductive paste provided by the present invention also has high electron mobility, and its printed coating has good stretchability as well as electrical and thermal conductivity, and has broad application prospects in the field of electrically heated flexible devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the “island-bridge” structure;

[0027] Figure 2 This is a physical picture of the intelligent temperature-controlled graphene-based conductive slurry prepared in Example 1 of the present invention;

[0028] Figure 3 This is a scanning electron microscope image of the intelligent temperature-controlled graphene-based conductive paste prepared in Example 1 of the present invention;

[0029] Figure 4 Schematic diagram of the screen printing process. DETAILED DESCRIPTION

[0030] The present invention provides an intelligent temperature-controlled graphene-based conductive paste, the components of which include a basic conductive paste and a thermal resistor; in parts by weight, the basic conductive paste includes: 5 to 50 parts of resin, 10 to 50 parts of conductive polymer, 1 to 2 parts of curing agent, and 5 to 30 parts of graphene;

[0031] The thermal resistor is an alkyl carbon chain compound and / or an inorganic phase change material; the mass of the alkyl carbon chain compound is 0 to 20% of the mass of the basic conductive paste, the mass of the inorganic phase change material is 0 to 30% of the mass of the basic conductive paste, and the addition amount of the alkyl carbon chain compound and the inorganic phase change material is not 0 at the same time.

[0032] In parts by weight, the basic conductive paste includes 5 to 50 parts of resin, preferably 10 to 40 parts, and further preferably 30 to 40 parts; the resin is preferably a water-based epoxy resin and / or a water-based polyurethane resin; the viscosity of the water-based epoxy resin is preferably 5000 to 10000 mPa·s, and the solid content is preferably 80 to 85%; the viscosity of the water-based polyurethane resin is preferably 800 to 1200 mPa·s, and the solid content is preferably 35 to 40%; in a specific embodiment of the present invention, the model of the water-based epoxy resin is preferably E-44; the model of the water-based polyurethane resin is preferably F0400.

[0033] Based on the weight of the resin, the basic conductive paste includes 10 to 50 parts of a conductive polymer, preferably 20 to 30 parts; the conductive polymer preferably includes one or more of polypyrrole, polythiophene, a polythiophene derivative, polyaniline and a polyaniline derivative; the polythiophene derivative is preferably polyethylenethiophene; the aniline derivative is preferably polyethylaniline.

[0034] Based on the weight of the resin, the basic conductive paste includes 1 to 2 parts of a curing agent, preferably 1 to 1.5 parts; the curing agent is preferably an aliphatic amine curing agent, and the aliphatic amine curing agent is preferably one or more of ethylenediamine and hexamethylenediamine; the addition of a small amount of curing agent in the present invention can increase the viscosity of the paste, so that the final conductive paste is viscous but will not solidify, thereby improving the dispersion stability of graphene in the conductive paste.

[0035] Based on the weight of the resin, the basic conductive paste includes 5 to 90 parts of graphene, preferably 5 to 80 parts, more preferably 5 to 50 parts, and most preferably 5 to 20 parts. In the present invention, the graphene is preferably flaky graphene; the flake diameter of the flaky graphene is preferably 20 nm, and the graphene is preferably multilayer graphene; the present invention combines graphene with a conductive polymer, and the conductive polymer can connect the graphene sheets to form a stable conductive system, namely an "island-bridge" structure; Figure 1 Schematic diagram of the "island-bridge" structure, where the conductive bridging material refers to a conductive polymer connecting graphene.

[0036] The intelligent temperature-controlled graphene-based conductive paste provided by the present invention includes a thermal resistor, which is an alkyl carbon chain compound and / or an inorganic phase change material; the alkyl carbon chain compound is preferably a paraffin-like substance, and the paraffin-like substance preferably includes one or more of liquid paraffin, polyethylene wax and oxidized polyethylene wax; the phase change temperature of the inorganic phase change material is preferably 50-100°C, and the inorganic phase change material is preferably a perovskite structure compound; the perovskite structure compound is preferably a titanate, more preferably one or more of barium titanate, strontium titanate and barium titanate doped with rare earth elements; the rare earth element in the barium titanate doped with rare earth elements is preferably Sr and / or Ce; the chemical formula of the barium titanate doped with rare earth elements is preferably Ba 1-x M x TiO3, wherein M is Sr or Ce, and the value of x is preferably 0.2 to 0.3; in a specific embodiment of the present invention, the barium titanate doped with rare earth elements is preferably barium strontium titanate (Ba 1-x Sr x TiO3).

[0037] In the present invention, the mass of the alkyl carbon chain compound is 0-20% of the mass of the basic conductive paste, preferably 1-10%, and more preferably 1-5%, the mass of the inorganic phase change material is 0-30% of the mass of the basic conductive paste, preferably 5-20%, and more preferably 10-15%, and the added amount of the alkyl compound and the inorganic phase change material is not 0 at the same time.

[0038] In the present invention, the paraffin-like substance is preferably used in the form of an aqueous wax emulsion; the solid content of the aqueous wax emulsion is preferably 20-30%; the emulsification type of the aqueous wax emulsion is preferably S-type, the softening point is preferably 100-110°C, and the pH value is preferably 8-9; in a specific embodiment of the present invention, the aqueous wax emulsion is preferably a polyethylene wax emulsion; the brand of the polyethylene wax emulsion is preferably DF936, and the manufacturer is Dingfengsheng Chemical Technology Co., Ltd.; the mass of the aqueous wax emulsion is preferably 5-20% of the mass of the basic conductive paste, and more preferably 5%, 10%, 15% or 20%.

[0039] The present invention adds a thermal resistor to the graphene-based conductive slurry, and after the printed fabric is used, the purpose of intelligent temperature control can be achieved, thereby improving the safety of the product. The thermal resistor used in the present invention has the characteristics of low viscosity, high melting point, excellent chemical stability and waterproofness, etc., and can be more evenly attached to the fabric, and can also improve the softness and service life of the fabric, thereby meeting the requirements of human comfort.

[0040] In the present invention, the viscosity of the intelligent temperature-controlled graphene-based conductive paste at 20-25°C is 12500-14000 mPa·s, preferably 13000 mPa·s, and the pH value of the intelligent temperature-controlled graphene-based conductive paste is 7-8; the intelligent temperature-controlled graphene-based conductive paste is a non-ionic, non-toxic conductive paste, preferably stored at 10-40°C.

[0041] The present invention also provides a method for preparing the intelligent temperature-controlled graphene-based conductive slurry described in the above scheme, comprising the following steps:

[0042] first mixing the resin, the conductive polymer and the curing agent to obtain a mixture;

[0043] The mixed material and graphene are mixed for the second time to obtain a basic conductive paste;

[0044] The basic conductive paste and the thermal resistor are mixed for the third time to obtain the intelligent temperature-controlling graphene-based conductive paste.

[0045] The present invention first mixes the resin, carbon slurry, conductive polymer and curing agent to obtain a mixture. In the present invention, the rotation speed of the first mixing is preferably 500-600 r / min; the rotation speed of the second mixing is preferably 300-900 r / min, more preferably 500-600 r / min; the rotation speed of the third mixing is preferably 500-1200 r / min, more preferably 1000-1200 r / min; the present invention has no special requirements for the time of the first mixing, the second mixing and the third mixing, as long as the raw materials can be mixed evenly.

[0046] The present invention also provides the use of the intelligent temperature-controlling graphene-based conductive paste described in the above scheme or the intelligent temperature-controlling graphene-based conductive paste prepared by the preparation method described in the above scheme in an electrothermal flexible device.

[0047] The present invention also provides an electrothermal flexible device, including a flexible substrate and a conductive layer printed on the surface of the flexible substrate; the conductive layer is formed by printing the intelligent temperature-controlled graphene-based conductive paste described in the above scheme or the intelligent temperature-controlled graphene-based conductive paste prepared by the preparation method described in the above scheme. The present invention has no requirements for the flexible substrate, and a flexible substrate familiar to those skilled in the art can be used, such as polyester; the printing method is preferably screen printing; the present invention has no special requirements for the thickness of the conductive layer, and it can be determined according to actual needs; the electrothermal flexible device provided by the present invention has high heating efficiency, fast temperature rate, and uniform heating, and will not overheat. The temperature under a voltage of 120V can be maintained in the range of 35 to 55°C, and it has good safety.

[0048] The present invention has no special requirements for the type of the electrothermal flexible device, which can specifically be a high-voltage series product, a low-voltage series product or a yarn product sized with an electrothermal slurry; the high-voltage series products are preferably sauna blankets, shawls, cushions, pet mats and other related products; the low-voltage series products are preferably scarves, gloves, hats, eye masks, shawls, knee pads and other related products.

[0049] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The model of the waterborne polyurethane used in the following examples is F0400, and the model of the waterborne epoxy resin is E-44, both of which are commercially available products.

[0051] Example 1

[0052] In parts by weight, the components of the basic conductive paste are: 40 parts of waterborne polyurethane, 1 part of ethylenediamine curing agent, 30 parts of polyaniline, and 5 parts of flake graphene;

[0053] The thermal resistance agent is a water-based wax emulsion, model DF936, produced by Dingfengsheng Chemical Technology Co., Ltd., and the dosage is 5% of the mass of the basic conductive slurry.

[0054] The preparation method of the intelligent temperature-controlled graphene-based conductive paste is as follows: water-based polyurethane, ethylenediamine curing agent and polyaniline are mixed evenly at a rotation speed of 500 r / min, and then flake graphene is added and mixed evenly at a rotation speed of 600 r / min, and then a thermal resistor is added and mixed evenly at a rotation speed of 1000 r / min to obtain an intelligent temperature-controlled graphene-based conductive paste with a viscosity of 13000 to 14000 mPa·s.

[0055] Figure 2 A physical picture of the intelligent temperature-controlled graphene-based conductive slurry prepared in this embodiment; Figure 3 This is a scanning electron microscope image of the intelligent temperature-controlled graphene-based conductive paste prepared in this embodiment; Figure 3 It can be seen that the graphene in the intelligent temperature-controlled graphene-based conductive slurry prepared by the present invention is evenly dispersed without agglomeration.

[0056] Example 2

[0057] Other conditions are consistent with those in Example 1, except that the amount of the thermal resistor is changed to 10% of the mass of the basic conductive paste. The viscosity of the obtained intelligent temperature-controlled graphene-based conductive paste is 13000-13500 mPa·s.

[0058] Example 3

[0059] Other conditions were consistent with those in Example 1, except that the amount of the thermal resistor was changed to 15% of the mass of the basic conductive paste. The viscosity of the obtained intelligent temperature-controlled graphene-based conductive paste was 12500-13000 mPa·s.

[0060] Example 4

[0061] Other conditions were consistent with those in Example 1, except that the amount of the thermal resistor was changed to 20% of the mass of the basic conductive paste. The viscosity of the obtained intelligent temperature-controlled graphene-based conductive paste was 12000-12500 mPa·s.

[0062] Comparative Example 1

[0063] The other conditions were the same as those in Example 1, except that the addition of the thermal resistor was omitted.

[0064] Test Example 1

[0065] 1. Thermal resistance performance test: The polyester flexible coated fabric is passed through a screen printing platform, and the conductive paste prepared in Examples 1 to 4 or Comparative Example 1 is spread on the screen using a screen plate and a matching scraper, and continuous printing is performed with a printing thickness of 30 μm to obtain a printed product. Figure 4 Schematic diagram of the screen printing process.

[0066] The printed product was powered on with a power supply device for 5 minutes at a voltage of 15V. The temperature of the printed product was tested with an infrared temperature tester. The current of the printed product was tested with a RPS3005C-2 DC regulated power supply and an infrared thermal imager. The results are shown in Table 1.

[0067] Table 1 Thermal resistance performance test results

[0068]

[0069] According to the data in Table 1, it can be seen that the resistance of the pure graphene fabric (Comparative Example 1) will decrease when electricity is applied, because graphene is a carbon material with a single atom thickness and has high electrical conductivity and thermal conductivity. When electricity is applied, the graphene fabric is injected with electrons, and its electron density increases, thereby enhancing the interaction between electrons, making it easier for electrons to transfer charges, and current will flow more easily through the graphene material. In addition, the movement of charges on the surface of the material can be promoted by applying electricity, thereby increasing the conductivity.

[0070] With the increase of thermal resistors, the resistance of printed products has increased. This is mainly because the conductive paste with thermal resistors can form a protective layer with high thermal resistance on the surface of the fabric, thereby reducing the thermal conductivity of the printed fabric surface, slowing down the transfer of heat to the inside of the fabric, and keeping the temperature of the printed fabric surface within a certain range.

[0071] 2. Basic property test

[0072] The intelligent temperature-controlled graphene-based conductive paste prepared in Example 3 was used to print on the surface of the polyester flexible coated fabric. The printing method was consistent with the thermal resistance performance test, and the printing thickness was 0.1 to 0.3 mm to obtain a printed product. The bending resistance, tensile resistance, electrothermal efficiency, far-infrared wavelength, radiation, etc. of the printed product were tested, and the results are shown in Table 2.

[0073] Table 2 Basic property test results

[0074]

[0075] According to the results in Table 2, it can be seen that after printing with the intelligent temperature-controlled graphene-based conductive paste of the present invention, the resulting printed product has excellent bending and folding resistance, strong stretchability, high electrothermal efficiency, can emit far-infrared light waves, and generates no radiation when used.

[0076] 3. Stability test

[0077] The intelligent temperature-controlled graphene-based conductive paste prepared in Examples 1 to 4 was placed at room temperature for 90 days, and the graphene sheets did not aggregate, and the electrothermal properties and the like remained substantially unchanged, indicating that the conductive paste of the present invention has excellent stability.

[0078] Example 5

[0079] The other conditions were the same as those in Example 1, except that polyaniline was replaced by polythiophene.

[0080] Example 6

[0081] The other conditions were the same as those in Example 1, except that polyaniline was replaced by polypyrrole.

[0082] Example 7

[0083] The other conditions were the same as those in Example 1, except that the amount of graphene was changed to 15 parts and the amount of waterborne polyurethane was changed to 50 parts.

[0084] Example 8

[0085] The other conditions were the same as those in Example 1, except that the polyurethane resin was changed to a water-based epoxy resin, model E44.

[0086] The thermal resistance properties of the conductive pastes prepared in Examples 5 to 8 were tested according to the above method. The results showed that effective intelligent temperature control can be achieved, and the conductive pastes have good stability. The resulting printed products have excellent bending and folding resistance, strong stretchability, and excellent basic properties.

[0087] Example 9

[0088] Other conditions are the same as those in Example 1, except that the thermal resistor is changed to a perovskite thermal resistor, specifically barium strontium titanate (Ba 1-x Sr x TiO3, x = 0.3), the addition amount is 5%, 10%, 15%, 20% of the mass of the basic conductive paste respectively;

[0089] The thermal resistance performance of the obtained intelligent temperature-control conductive slurry was tested according to the method of Test Example 1. The test results are shown in Table 3. At the same time, the slurry of Comparative Example 1 was tested under the same conditions and the test results were recorded.

[0090] Table 3 Thermal resistance performance test results

[0091]

[0092] According to the data in Table 3, it can be seen that with the increase in the amount of thermal resistor, the resistance of the printed product increases, which can keep the temperature of the printed fabric surface within a certain range and avoid overheating.

[0093] Example 10

[0094] Other conditions are the same as those in Example 1, except that the heat resistance agent is replaced by barium titanate or strontium titanate, and the addition amount is 5% of the mass of the basic conductive paste. The results show that when the heat resistance agent is barium titanate or strontium titanate, the obtained conductive paste has the effect of intelligent temperature control, which can keep the temperature of the printed fabric surface within a certain range and avoid overheating.

[0095] Comparative Example 2

[0096] The other conditions were the same as those in Example 1, except that the addition of polyaniline was omitted. The results showed that after the conductive polymer was omitted, the off-grid property and printing stability of the conductive paste became poor, making it difficult to print, and the paste easily fell off the flexible substrate, affecting the performance of the product.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An intelligent temperature-controlled graphene-based conductive slurry, characterized in that: The components include a basic conductive paste and a thermal resistor; in terms of weight, the basic conductive paste includes: 5 to 50 parts of resin, 10 to 50 parts of conductive polymer, 1 to 2 parts of curing agent, and 5 to 30 parts of graphene; The thermal resistor is an alkyl carbon chain compound and / or an inorganic phase change material; the mass of the alkyl carbon chain compound is 0 to 20% of the mass of the basic conductive paste, the mass of the inorganic phase change material is 0 to 30% of the mass of the basic conductive paste, and the addition amount of the alkyl carbon chain compound and the inorganic phase change material is not 0 at the same time.

2. The intelligent temperature-controlled graphene-based conductive slurry according to claim 1, characterized in that: The alkyl carbon chain compound is a paraffin-type substance; and the inorganic phase change material is a perovskite structure compound.

3. The intelligent temperature-controlled graphene-based conductive slurry according to claim 2, characterized in that: The paraffin-based substance includes one or more of liquid paraffin, polyethylene wax and oxidized polyethylene wax; and the perovskite structure compound is titanate.

4. The use according to claim 3, characterized in that: The titanate includes one or more of barium titanate, strontium titanate and barium titanate doped with rare earth elements; The paraffin material is used in the form of an aqueous wax emulsion; the solid content of the aqueous wax emulsion is 20-30%; the mass of the aqueous wax emulsion is 5-20% of the mass of the basic conductive paste.

5. The intelligent temperature-controlled graphene-based conductive paste according to claim 1, characterized in that: The conductive polymer includes one or more of polypyrrole, polythiophene, polythiophene derivatives, polyaniline and polyaniline derivatives.

6. The intelligent temperature-controlled graphene-based conductive paste according to claim 1, characterized in that: The curing agent is an aliphatic amine curing agent; The resin is water-based epoxy resin and / or water-based polyurethane.

7. The method for preparing the intelligent temperature-controlled graphene-based conductive paste according to any one of claims 1 to 6, characterized in that: The following steps are involved: first mixing the resin, the conductive polymer and the curing agent to obtain a mixture; The mixed material and graphene are mixed for the second time to obtain a basic conductive paste; The basic conductive paste and the thermal resistor are mixed for the third time to obtain the intelligent temperature-controlling graphene-based conductive paste.

8. The preparation method according to claim 7, characterized in that: The rotation speed of the first mixing is 500-600 r / min; the rotation speed of the second mixing is 300-900 r / min; the rotation speed of the third mixing is 500-1200 r / min.

9. Use of the intelligent temperature-controllable graphene-based conductive paste according to any one of claims 1 to 6 or the intelligent temperature-controllable graphene-based conductive paste prepared by the preparation method according to claim 7 or 8 in electrothermal flexible devices.

10. An electrothermal flexible device, characterized in that: It comprises a flexible substrate and a conductive layer printed on the surface of the flexible substrate; the conductive layer is formed by printing the intelligent temperature-controllable graphene-based conductive paste described in any one of claims 1 to 6 or the intelligent temperature-controllable graphene-based conductive paste prepared by the preparation method described in claim 7 or 8.

Images