CN111609454A

CN111609454A - Electric heating picture and preparation method thereof

Info

Publication number: CN111609454A
Application number: CN202010381221.3A
Authority: CN
Inventors: 谭化兵; 潘智军
Original assignee: Anhui Aerospace and PMA Health Technology Co Ltd
Current assignee: Anhui Aerospace and PMA Health Technology Co Ltd
Priority date: 2020-05-08
Filing date: 2020-05-08
Publication date: 2020-09-01
Anticipated expiration: 2040-05-08
Also published as: CN111609454B

Abstract

The invention discloses an electrothermal picture and a preparation method thereof, and the method comprises the steps of attaching a graphene hybrid film on the surface of an insulating substrate and then carrying out first hot-pressing treatment; then, current-carrying electrodes are printed at two opposite ends of the graphene hybrid film; then attaching an insulating substrate to the other side of the graphene hybrid film, and carrying out second hot-pressing treatment to obtain a graphene hybrid heating body; and finally, assembling the decorative picture, the graphene hybrid heating body and the heat insulation board by adopting a metal frame according to the sequence from the outside to the inside, and arranging adjacent two layers at intervals to obtain the graphene hybrid heating body. The graphene hybrid film in the electric heating picture has high heat resistance and heat conductivity, the sheet resistance and flexibility of the graphene hybrid film can be regulated, the service life of the prepared electric heating picture is obviously prolonged, the electric-thermal conversion efficiency of the electric heating picture is obviously improved, and the electric-thermal conversion efficiency of the electric heating picture reaches over 72 percent; the energy-saving and heating effects of the electric heating picture are obviously improved, and the prepared heating picture is high in far infrared radiation efficiency after being electrified, so that the far infrared physiotherapy requirement is met.

Description

Electric heating picture and preparation method thereof

Technical Field

The invention belongs to the field of manufacturing of electric heating products, relates to application of a novel graphene material in the field of electric heating pictures, and particularly relates to a manufacturing structure and a manufacturing method of the novel graphene heating body material.

Background

In recent years, the electric heating technology and the market are rapidly developed, more and more electric heating equipment enters common families particularly under the support of national northern coal-to-electricity policy, the safe and efficient heating requirements of northern families in the heating season are met, and important products and technical support are provided for continuously improving the air quality of northern main cities.

Among all electric heating products, an electric heating picture (heating picture) is a product with great market prospect, because the electric heating picture organically combines heating with home interior decoration, namely, compared with other heating products, the electric heating picture has unique advantages in functionality and aesthetic characteristics. In addition, the electric heating picture does not occupy indoor space, has good far infrared physical therapy characteristic, and is more and more accepted and popular by the market.

The traditional carbon crystal heating body is adopted in the existing electric heating paintings which are used in a large quantity, and along with the increase of the service time, the stability of the carbon crystal heating body is deteriorated at high temperature due to the characteristics of the material of the carbon crystal heating body, the resistance of the heating body is increased, the power of the electric heating paintings is reduced, so that the heating effect of the electric heating paintings is obviously reduced, and the electric heating paintings cannot be used continuously.

Graphene is a new material of great strategy developed in recent years, has the remarkable advantages of good heat conductivity and good electrical conductivity, and is gradually applied to various electronic products. In the field of electric heating, the graphene also gradually exerts the material advantages thereof, and gradually replaces the traditional carbon crystal heating element in an electric heating element to form the unique technical advantages of the graphene material.

However, when the conventional electric heating picture uses graphene slurry as an original conductive material to prepare a heating element, the graphene slurry contains a large amount of resin materials, and the temperature resistance of the graphene slurry is generally poor, so that the long-term high-temperature stability (higher than 120 ℃) of the heating element also has a problem. Especially, in the electric heating picture, because of the cavity and the thermal resistance (see figure 1), the heat on the surface of the heating body can not be transferred in time through radiation, and in the back surface of the heating body (pointing to one side of the back surface of the electric heating picture), a large amount of heat is isolated in the cavity between the heating body and the thermal insulation layer under the blocking of the reflecting film and the thermal insulation layer, so that the temperature of the heating body is further promoted.

In the application process of the existing electric heating paintings, the problem of poor stability of the heating body of the electric heating paintings is solved, and the electric heating paintings are characterized in that the power of the electric heating paintings gradually decreases along with the increase of the service time, the resistance of the heating body increases, so that the heating effect of the electric heating paintings gradually becomes poor, the popularization and the promotion of the electric heating paintings in heating application are seriously influenced, and the large-scale application of the electric heating paintings is limited.

In recent years, in order to improve the product competitiveness of the electric heating picture in the field of electric heating, namely the heating effect of the electric heating picture, the temperature of a core heating body of the electric heating picture is gradually improved, holes are formed in the top end and the bottom end of the heating picture simultaneously, the effect of combining natural convection with infrared radiation is formed, the requirement for the high-temperature stability of the heating body is higher, and in order to take the far infrared effect into consideration, the carbon series heating body is still taken as the mainstream development direction as the whole.

With the rapid development of micro-nano carbon materials, the artificial graphite heat-conducting film and the graphene heat-conducting film are novel materials, and the requirements of a heating body on heating materials are very met based on a high-temperature heat treatment process in a manufacturing process. However, the commercial artificial graphite heat-conducting film and the graphene heat-conducting film both have the problems of small sheet resistance (sheet resistance <1ohm/sq) and easy damage in the die cutting process. The square resistance is too small, so that the heating body can only be designed into a U-shaped series connection structure, and the reliability is poor. The die cutting process is easy to damage, so that the heating body is easy to generate cracks and other defects which are difficult to detect, the subsequent hot-pressing yield of the product can be seriously influenced, and potential safety hazards in use are caused.

Aiming at the problems, the invention solves the problems by introducing the graphene-carbon nano tube hybrid graphitized film as a heating element material. The graphene-carbon nanotube hybrid graphitized film is formed by a thermal reduction process at the temperature of over 500 ℃, so that the graphene-carbon nanotube hybrid graphitized film has excellent heat resistance and stability, can effectively improve far infrared emission efficiency as a pure carbon heating body, and has far infrared emission characteristics more meeting the requirements of human body physical therapy.

Disclosure of Invention

The invention aims to provide an electric heating picture and a preparation method thereof aiming at the technical problems of the existing electric heating picture made of graphene, wherein the square resistance of a graphene hybrid heating film of a heating element in the electric heating picture prepared by the method is large, so that the design requirement of the heating element with a parallel structure in the electric heating picture is met; the heating element prepared by the graphene hybrid heating film in the electric heating picture has good temperature resistance, is used at high temperature for a long time, has high long-term high-temperature stability and stable heating power, and the port resistance of the heating element is stable, so that the prepared electric heating picture has good long-term heating effect; the graphene electric heating picture prepared by the graphene film heating body is high in far infrared radiation efficiency, the overall forward far infrared conversion efficiency of the electric heating picture is obviously improved, and the far infrared physiotherapy requirement can be further met.

In order to achieve the purpose of the invention, the invention provides a preparation method of an electric heating picture on one hand, which comprises the following steps:

1) firstly, attaching a graphene hybrid film to the surface of a first heater insulating substrate, and then carrying out first hot-pressing treatment; then, current-carrying electrodes are printed at two opposite ends of the graphene hybrid film; then attaching a second heating element insulating substrate to the other side of the graphene hybrid film, and carrying out second hot-pressing treatment to obtain a graphene hybrid heating element;

2) and (3) assembling the decorative picture, the graphene hybrid heating body and the heat-insulating plate in sequence from the outside to the inside by adopting a metal frame, and arranging adjacent two layers at intervals to obtain the electric heating picture.

The graphene hybrid membrane in the step 1) is prepared by the following steps in sequence:

1-1) preparing the following raw materials in parts by weight

1-2) uniformly mixing the raw materials to prepare heating slurry, coating the heating slurry on the surface of an insulating base material, and then drying the heating slurry to solidify the heating slurry to form a graphene-carbon nanotube-base material composite membrane;

1-3) stripping an insulating substrate of the graphene-carbon nanotube-substrate composite film, and performing thermal reduction treatment to prepare a thermal reduction-graphene composite film;

1-4) rolling the thermal reduction-graphene composite film to obtain the graphene composite film.

Particularly, the raw materials in the step 1-1) are as follows:

particularly, the raw materials in the step 1-1) are in the following ratio:

wherein, the dispersant in the step 1-1) is selected from one or more of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), Sodium Dodecyl Sulfate (SDS) or carboxymethyl cellulose (CMC); the solvent is selected from water and/or N-methyl pyrrolidone; the graphene oxide is graphene oxide powder with the lamella size of 2-100 mu m, preferably 3-10 mu m; the carbon nanotube is a single-walled or multi-walled carbon nanotube, preferably a single-walled carbon nanotube.

In particular, the diameter of the single-walled carbon nanotube is 0.5-100nm, preferably 1.5 nm; the length is 1 to 100 μm, preferably 15 μm.

Wherein the drying treatment temperature in the step 1-2) is 90-180 ℃, and preferably 150 ℃; the drying time is 20-30 min, preferably 25 min.

In particular, the thickness of the heat-generating paste layer cured after the drying treatment is 10 to 1000. mu.m, preferably 30 to 200. mu.m, and more preferably 50 μm.

Wherein, the heating slurry is coated on the surface of the insulating base material in the step 1-2) by adopting a coating or printing mode.

In particular, the thickness of the heat generating paste applied to the surface of the insulating base material is 10 to 1000. mu.m, preferably 50 to 200. mu.m, and more preferably 100. mu.m.

Particularly, the viscosity range of the heating slurry is 500 to 20000cPs, and preferably 2000 to 8000 cPs.

Particularly, the insulating substrate in the step 1-2) is a release film, preferably a PET release film, a PP release film or a PE release film, and more preferably a PET release film.

Wherein the temperature of the thermal reduction treatment in the step 1-3) is 500-1000 ℃, and is preferably 800 ℃; the thermal reduction treatment time is 3-10h, preferably 6.5 h; the heating speed is 4-20 ℃/min, preferably 8 ℃/min.

Particularly, the method also comprises the step of taking out the thermal reduction-graphene composite membrane when the temperature is naturally reduced to be lower than 350 ℃, preferably 200-350 ℃, more preferably 250-300 ℃ and more preferably 300 ℃ after the thermal reduction treatment.

In particular, inert gas is introduced during the thermal reduction treatment as protective gas, wherein the inert protective gas is argon.

Particularly, the speed of stripping the insulating base material in the step 1-3) is 0.5-10 m/min, and preferably 2 m/min.

Wherein the pressure of the rolling treatment in the step 1-4) is 1-15MPa, preferably 12 MPa; the density of the rolled graphene hybrid heating film is 0.5-2.2g/cm³Preferably 1.5g/cm³(ii) a The thickness is 0.5-10 μm, preferably 10 μm; the sheet resistance is preferably from 1 to 200ohm/sq, more preferably from 30 to 100ohm/sq, and still more preferably 100 ohm/sq.

Wherein the hot pressing pressure of the first and second hot pressing treatment in the step 1) is 0.5-0.8MPa, preferably 0.7 MPa; the hot pressing temperature is 120-200 ℃, and the preferred temperature is 150 ℃; the hot pressing time is 30-240s, preferably 160 s.

Particularly, after the first and second hot pressing treatments, a baking treatment is further performed, wherein the baking temperature is 120-; the baking time is 30-120min, preferably 40-90min, and further 45 min.

Particularly, the first heating element insulating substrate and the second heating element insulating substrate are polyimide films, epoxy resin plates or mica plates.

In particular, it also comprises a step 1A): carrying out patterning treatment on the graphene hybrid heating film, and then attaching the graphene hybrid heating film to the surface of the first heating body base material:

firstly, compounding a graphene hybrid heating film on the surface of a release film to prepare a graphene hybrid combined film; and then, according to the design requirements of the resistance of the heating element for the electric heating picture, die cutting, punching and patterning are carried out on the graphene hybrid combined film by using a die cutting machine to obtain a patterned-graphene hybrid combined film, the resistance of the patterned-graphene hybrid combined film is consistent with the resistance of the heating element for the electric heating picture, and then the patterned-graphene hybrid combined film is attached to the surface of the first heating element insulating substrate.

Particularly, the release film is selected from release films with a release force of 5gf/in (usually 5 to 20gf/in), and the release film is selected from PET release film, PP release film or PE release film.

Particularly, the patterning treatment is to perform die cutting and punching on the graphene hybrid composite film by using a die cutting machine, wherein the holes are round holes, square holes or strip-shaped holes; or die-cutting the graphene hybrid combined film into strips to form a strip graphene hybrid combined film array arranged at intervals.

In particular, the patterning process is preferably a process of patterning the graphene hybrid composite film into a strip-shaped graphene hybrid composite film array.

Particularly, the method further comprises coating an adhesive on the surface of the first heater insulating substrate, and attaching the graphene hybrid heating film to the surface of the first heater insulating substrate at a temperature of 80-120 ℃ (preferably 100 ℃).

In particular, the adhesive is selected from high temperature resistant adhesives, preferably epoxy adhesive or silicone adhesive. The high-temperature adhesive is selected from organic silicon adhesive, phenolic resin adhesive, urea-formaldehyde resin adhesive, temperature-resistant epoxy adhesive, polyimide adhesive and the like; for example, high temperature epoxy glue such as TE-9249, TE-9128 type high temperature epoxy glue, etc.; a silicone adhesive, such as loctite 518.

Particularly, an adhesive is coated on the surface of the first heat emitter insulation substrate, and the patterned-graphene hybrid composite film is attached to the surface of the first heat emitter insulation substrate at a temperature of 120-.

And in the step 1), silver pastes are respectively printed on two opposite ends of the graphene hybrid heating film by adopting a screen printing mode for the current-carrying electrode, and the silver pastes are dried and cured to form the silver paste current-carrying electrode.

Particularly, the thickness of the printed silver paste wet film is 20-60 μm, preferably 30 μm; the temperature for drying and curing is 130-160 ℃, and preferably 150 ℃.

Particularly, the granularity of the silver powder selected by the silver paste is 1-3 mu m, and the solid content of the silver powder is more than 60%, preferably more than 70%.

Silver paste is printed on two opposite ends of the patterned-graphene hybrid combined film respectively, and the silver paste is dried and solidified to form a silver paste current-carrying electrode.

Particularly, the end part of the current-carrying electrode is connected with an external wire and is used for connecting an external power supply and providing electric energy for the heating body.

Particularly, the electric heating picture temperature controller is arranged on an external wire and used for controlling the temperature of the electric heating picture.

And a hole is formed in the second heating element insulating substrate, the position of the hole corresponds to the tail end position of the printed current-carrying electrode, and the hole is used for connecting an external wire with the tail end of the current-carrying electrode.

Particularly, the step 1) further comprises coating an adhesive on the surface of the second heating element insulating substrate, and attaching the other side of the graphene hybrid heating film to the surface of the second heating element insulating substrate at a temperature of 80-120 ℃ (preferably 100 ℃).

And the second hot-pressing treatment is to hot-press and package the graphene hybrid heating film and the current carrying bar electrode in the first heating element insulating substrate and the second heating element insulating substrate, and the patterned-composite heating element film is positioned between the two heating element insulating substrates to obtain the heating element for the electric heating picture.

Wherein, the heat insulation board in the step 2) is one of a glass magnesium board, a polyurethane heat insulation board and an extruded sheet (XPS), and is preferably a glass magnesium board; the decorative painting selects high-temperature-resistant canvas or a PET (polyethylene terephthalate) base material, and decorative painting patterns are sprayed and painted on the surface of the base material through a UV (ultraviolet) spray painting machine.

In particular, the distance between two adjacent layers is 3 to 15mm, preferably 5 mm. The distance between two adjacent layers is 3-15mm, preferably 5mm, from the surface layer decorative picture, the graphene hybrid heating body and the heat insulation board from the outside to the inside.

In particular, it also comprises a step 2A): covering a PET film on the surface of the decorative picture or coating curing type UV gloss oil on the surface of the surface decorative picture, irradiating by UV light, and curing to form a decorative picture protective layer.

Especially, the protection layer of the decorative picture in the assembled graphene electrothermal picture faces outwards and faces one side of a user, and the protection layer is used for protecting the patterns on the surface of the decorative picture and preventing the decorative picture base material and the patterns from being damaged in the using process.

The invention provides a preparation method of an electric heating picture, which comprises the following steps:

2) covering an infrared reflecting layer on the surface of one side of the heat-insulating plate by means of bonding, coating, printing or vapor deposition, wherein the infrared reflecting layer is an aluminum, silver, copper, polyethylene, glass fiber or PET film, and preparing the infrared reflecting-heat-insulating plate;

3) the method comprises the steps of assembling a decorative picture, a graphene hybrid heating body and an infrared reflection-insulation board in sequence from the outside to the inside by adopting a metal frame, and arranging adjacent two layers at intervals to obtain the graphene electric heating picture, wherein an infrared reflection layer of the infrared reflection-insulation board faces towards a graphene hybrid heating body layer.

Wherein, the thickness of the infrared reflecting layer in the step 2) is 0.1-1000 μm, preferably 10-200 μm, and more preferably 100 μm; the heat insulation board is one of a glass magnesium board, a polyurethane board and an extruded board, and is preferably a glass magnesium board; the infrared reflecting layer is preferably an aluminum, silver or copper thin film.

In particular, the vapor deposition method is selected from Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD).

Wherein, in the step 3), the spacing distance between two adjacent layers is 3-15mm, preferably 5 mm. The distance between two adjacent layers, namely the surface decorative picture, the graphene hybrid heating body and the infrared reflection-insulation board from the outside to the inside, is 3-15mm, preferably 5 mm.

The invention also provides a preparation method of the electrothermal picture, which comprises the following steps:

2) coating infrared enhancement slurry on the surface of the insulating plate of the graphene heating body layer, then baking, and curing the infrared enhancement slurry to form an infrared enhancement layer to obtain an infrared enhancement-graphene hybrid heating body;

3) the method comprises the steps of assembling a decorative picture, an infrared enhancement-graphene hybrid heating body and a heat insulation board in sequence from the outside to the inside by adopting a metal frame, and arranging adjacent two layers at intervals to obtain the graphene electric heating picture, wherein an infrared enhancement layer of the infrared enhancement-graphene heating body faces towards the decorative picture.

Wherein, the infrared reinforced slurry in the step 2) comprises an infrared reinforced material and a binder, wherein the weight ratio of the infrared reinforced material to the binder is (10-30) to (70-90), preferably 20: 80.

Particularly, the infrared reinforcing material is one or more of graphite, a micro-nano carbon material, nano silicon powder, metal oxide, silicon carbide, boron carbide, sodium silicate and aluminum silicate.

Particularly, the micro-nano carbon material is diamond, diamond-like carbon, graphene, graphite alkyne, carbon black or carbon nano tube; the metal oxide is ferric oxide, nickel oxide, chromium oxide, copper oxide, manganese oxide, cobalt oxide or aluminum oxide.

Particularly, the infrared enhancement layer material is one or more of silicon carbide, graphene, silicon oxide or graphite; the adhesive is selected from waterborne epoxy resin, waterborne acrylic resin, vinyl acetate resin, waterborne polyurethane resin, phenolic resin or polyester resin, and is preferably waterborne epoxy resin. .

In particular, the infrared enhancement layer material is selected from powder with the grain diameter of 0.1-3 μm, preferably 0.1-0.5 μm; the viscosity of the infrared enhancement slurry is 1000-; the thickness of the infrared enhancement layer is 0.1 to 1000 μm, preferably 10 to 300 μm, and more preferably 200 μm.

In particular, the infrared enhancing paste is applied by spraying, printing, spin coating, curtain coating or deposition.

The infrared enhancement layer is made of silicon oxide and graphite, and the weight ratio of the silicon oxide to the graphite is 1: (0.5-3), preferably 1: 1.

In particular, the baking treatment temperature in the step 2) is 120-160 ℃, and preferably 150 ℃; the baking time is 20-40min, preferably 30 min.

2) coating infrared absorption slurry on the back of the surface layer decorative picture, baking, and curing the infrared absorption slurry to form an infrared absorption layer to obtain an infrared absorption layer-decorative picture;

3) the infrared absorption-decoration picture, the graphene hybrid heating body and the heat insulation board are assembled in sequence from the outside to the inside by adopting a metal frame, and the adjacent two layers are arranged at intervals to prepare the graphene electric heating picture, wherein the infrared absorption layer of the infrared absorption-decoration picture faces towards the graphene heating body.

Wherein, the infrared absorption slurry in the step 2) comprises an infrared absorption material and a binder, wherein the weight ratio of the infrared absorption material to the binder is 10-30:70-90, preferably 15: 85.

Particularly, the infrared absorption material is one or more of indium tin oxide, tin antimony oxide, tungsten cesium oxide, tungsten tin oxide, zinc oxide, silicon oxide, aluminum oxide, calcium carbonate, titanium dioxide, wollastonite, silica gel powder, graphite, a micro-nano carbon material, nano silicon powder, melamine, polyphenylene sulfide, boric acid, resin, polyethylene wax, zinc stearate and white oil.

Particularly, the micro-nano carbon material is graphene, graphite alkyne, carbon black or a carbon nano tube; the resin is PP (polypropylene), PET, PC (polychloroprene), ABS (polyacrylonitrile-butadiene-styrene), PMMA (polymethyl methacrylate), PS (polystyrene) or PVC (polyvinyl chloride).

In particular, the infrared absorbing material is selected from carbon nano tube, graphene or zinc oxide.

In particular, the infrared absorbing material is selected as a powder having a particle size of 0.005 to 3 μm, preferably 0.005 to 0.5 μm; the adhesive is selected from waterborne epoxy resin, waterborne acrylic resin, vinyl acetate resin, waterborne polyurethane resin, phenolic resin or polyester resin, and is preferably waterborne acrylic resin.

Particularly, the viscosity of the absorption layer slurry is 500-5000cps, preferably 1500 cps; the thickness of the infrared absorption layer is 0.1 to 1000. mu.m, preferably 50 to 200. mu.m, and more preferably 150. mu.m.

Particularly, the infrared enhancement slurry is coated by adopting a spraying, printing, spin coating, curtain coating or depositing mode; the baking treatment temperature in the step 2) is 120-160 ℃, and preferably 130 ℃; the baking time is 20-40min, preferably 40 min.

3) covering an infrared reflecting layer on the surface of one side of the heat-insulating plate by means of bonding, coating, printing or vapor deposition, wherein the infrared reflecting layer is an aluminum, silver, copper, polyethylene, glass fiber or PET film, and preparing the infrared reflecting-heat-insulating plate;

4) assembling the decorative picture, the infrared enhancement-graphene heating body and the infrared reflection-insulation board in sequence from the outside to the inside by adopting a metal frame, and arranging adjacent two layers at intervals to prepare the graphene electric heating picture, wherein an infrared enhancement layer of the infrared enhancement-graphene heating body faces towards the decorative picture; the infrared reflection layer of the infrared reflection-insulation board faces the infrared enhancement-graphene heating body layer.

4) assembling the infrared absorption-decoration picture, the graphene hybrid heating body and the infrared reflection-insulation board in sequence from the outside to the inside by adopting a metal frame, and arranging adjacent two layers at intervals to prepare the graphene electric heating picture, wherein an infrared absorption layer of the infrared absorption-decoration picture faces towards the graphene hybrid heating body; the infrared reflection layer of the infrared reflection-insulation board faces the graphene hybrid heating body layer.

In another aspect, the invention provides a method for preparing an electrothermal picture, comprising the following steps:

3) coating infrared enhancement slurry on the surface of the insulating plate of the graphene hybrid heating body layer, then baking, and curing the infrared enhancement slurry to form an infrared enhancement layer to obtain an infrared enhancement-graphene hybrid heating body;

4) assembling the infrared absorption-decoration picture, the infrared enhancement-graphene hybrid heating body and the heat preservation plate from the outside to the inside by adopting a metal frame, and arranging the adjacent two layers at intervals to prepare the graphene electric heating picture, wherein an infrared absorption layer of the infrared absorption-decoration picture faces towards the infrared enhancement-graphene hybrid heating body; the infrared enhancement layer of the infrared enhancement-graphene hybrid heating body faces towards the decorative picture.

In another aspect, the present invention provides a method for making an electrothermal picture, comprising the steps of:

4) covering an infrared reflecting layer on the surface of one side of the heat-insulating plate by means of bonding, coating, printing or vapor deposition, wherein the infrared reflecting layer is an aluminum, silver, copper, polyethylene, glass fiber or PET film, and preparing the infrared reflecting-heat-insulating plate;

5) assembling an infrared absorption-decoration picture, an infrared enhancement-graphene hybrid heating body and an infrared reflection-insulation board in sequence from the outside to the inside by adopting a metal frame, and arranging adjacent two layers at intervals to prepare the graphene electric heating picture, wherein an infrared absorption layer of the infrared absorption-decoration picture faces towards the infrared enhancement-graphene hybrid heating body; the infrared enhancement layer of the infrared enhancement-graphene hybrid heating body faces towards the decorative picture; the infrared reflection layer of the infrared reflection-insulation board faces the infrared enhancement-graphene hybrid heating body layer.

The invention further provides an electrothermal picture prepared by the method.

The electric heating picture prepared by the method adopts the graphene hybrid heating film made of graphene and carbon nanotube materials as the heating body material, and the graphene hybrid heating film has high electric conductivity and heat conductivity, so that the stability of the heating body of the electric heating picture is effectively improved. The heating layer material solves the functional hidden trouble that the heating layer material in the existing heating body has poor power attenuation and poor heating effect after being used because the material body contains resin adhesive (has poor long-term temperature resistance). In addition, the graphene-carbon nanotube hybrid high-thermal-conductivity film is used as a heating material, so that the emission efficiency of the graphene far infrared rays is effectively improved, and the conversion efficiency of the whole forward far infrared rays of the electric heating picture is obviously improved.

Compared with the prior art, the invention aims at solving the problem of poor temperature resistance of the heating element of the existing electric heating picture, adopts the graphene-carbon nano tube hybrid thermal reduction film as the heating element material, and has the following beneficial effects:

1. according to the invention, the carbon nanotube material is introduced into the heating element film of the electric heating picture and mixed with the graphene material, so that the connection network between the micro-viewing sheets of the graphene film is changed, the heat resistance and the heat conductivity are high, the sheet resistance and the flexibility of the graphene film can be regulated and controlled, the sheet resistance is increased to the range of dozens to hundreds of ohm/sq, and the design requirement of a heating element with a parallel structure in the electric heating picture is met.

2. The carbon nanotube hybridization process is introduced in the preparation process of the heating element film of the electric heating picture, so that the realization and strength maintenance of the ultrathin film in the preparation process of the material can be improved, and the key effects on the resistance regulation and control and the film flexibility guarantee are finally achieved.

3. The temperature resistance of the heating element prepared by the heating film of the electric heating picture is obviously higher than that of the heating element and the carbon crystal heating body prepared by the existing common graphene (such as CVD (chemical vapor deposition) graphene and graphene materials containing resin binders) film, thereby meeting the use requirement of the high-power heating picture;

4. the working life time of the heating body of the electric heating picture is obviously prolonged to more than 30000h, the electric-thermal radiation conversion efficiency is high to more than 72%, the service life of the electric heating picture is obviously prolonged, the energy conservation effect and the heating effect are obviously improved.

5. The heating element for the electric heating picture prepared by the heating film is a pure carbon heating element, and the prepared heating picture has higher far infrared radiation efficiency after being electrified and can better meet the requirements of far infrared physiotherapy.

Drawings

Fig. 1 is a schematic structural diagram of a printed electrode-graphene assembly prepared in example 1 of the present invention;

fig. 1A is a schematic structural diagram of a printed electrode-graphene assembly prepared in example 1A of the present invention;

FIG. 2 is a schematic view of an electrothermal picture according to the present invention;

FIG. 3 is a schematic view of another electric heating picture structure according to the present invention;

FIG. 4 is a schematic view of another electric heating picture according to the present invention.

Description of the reference numerals

1. A first heat emitter insulating substrate; 2. patterning a graphene hybrid composite film; 3. silver paste current carrying strip electrodes; 4. a heating element wire connecting terminal (the end part of a silver paste current carrying strip electrode); 5. a graphene heating element; 6. decorating the picture; 7. a protective layer; 8. fixing the frame; 9. a heat-insulating layer; 10. an infrared reflecting layer; 11. an infrared enhancement layer; 12. an active absorption layer.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

Graphene oxide powder and single-walled carbon nanotubes as raw materials are purchased from Nanjing Xiancheng nanomaterial science and technology Limited; the PET release film is purchased from Suzhou Yuxuan paper industry Co., Ltd; epoxy boards were purchased from sori electrical limited, nyu; epoxy resin adhesives were purchased from composite technologies, Inc., from Shangguan.

In the specific embodiment of the invention, the graphene oxide powder with the powder particle size of 3-10 μm is taken as an example for illustration, and other graphene oxide powders with the powder lamella size of 2-100 μm are also suitable for the invention; in addition to single-walled carbon nanotubes, multi-walled carbon nanotubes are also suitable for use in the present invention. In the present invention, the single-walled carbon nanotubes with a diameter of 1.5nm and a length of 15 μm are used as an example for explanation, and other single-walled or multi-walled carbon nanotubes with a diameter of 0.5-100nm and a length of 1-100 μm are suitable for the present invention.

Example 1

Preparation of graphene hybrid membrane

1. The raw materials were prepared in accordance with the following weights (. times.100 g)

Wherein the dispersant is Sodium Dodecyl Sulfate (SDS); the solvent is water;

2. preparation of Heater slurry

Adding graphene oxide powder, single-walled carbon nanotubes and a dispersing agent into a solvent, stirring and mixing uniformly to prepare a heating element slurry, wherein the viscosity of the heating element slurry is 5000cPs (usually 500-20000 cPs, preferably 2000-8000 cPs);

3. preparation of graphene-carbon nanotube composite film

Carrying out wet coating on the heating body slurry through a roll-type coating machine, and coating the heating body slurry on a PET (polyethylene terephthalate) release film serving as a substrate, wherein the coating thickness is controlled to be 100 micrometers (usually 10-1000 micrometers, preferably 50-200 micrometers); then, drying the coated film by adopting a tunnel drying oven, and curing the heating body slurry on the surface of the substrate to prepare the graphene-carbon nanotube-substrate composite film, wherein the drying temperature is controlled to be 150 ℃ (usually 90-180 ℃); drying for 25min (usually 20-30 min);

stripping the dried graphene-carbon nanotube-substrate composite film from the surface of the substrate by adopting a stripping and winding machine, and finishing winding to prepare the graphene-carbon nanotube composite film;

4. thermal reduction treatment

Placing the graphene-carbon nanotube composite membrane in a thermal reduction furnace, introducing high-purity argon as a protective gas, heating and maintaining at 800 ℃ (usually 500-1000 ℃), and performing thermal reduction treatment, wherein the heating speed is 8 ℃/min (usually 4-20 ℃/min); after the thermal reduction treatment is carried out for 6.5 hours (usually 3-10 hours), stopping heating, naturally cooling to a temperature lower than 300 ℃, and taking out to obtain a thermal reduction-graphene composite membrane;

in the production process of graphene oxide, a large number of oxygen-containing functional groups (groups) such as hydroxyl groups and carboxyl groups are introduced, and although dispersion in a solvent is facilitated, the active groups cause poor conductivity and thermal stability of graphene. In order to improve the conductivity and the thermal stability of the graphene oxide, the graphene oxide is placed in an inert gas (argon or nitrogen) atmosphere for calcination thermal reduction treatment, oxygen-containing groups are reduced, the structure of the graphene oxide can be recovered, and the conductivity and the thermal stability can be improved. Meanwhile, a small amount of unreduced oxygen-containing active groups still keep the easy dispersion characteristic of the graphene oxide in the solvent.

5. Roll-in treatment

Performing rolling treatment on the thermal reduction-graphene composite film by using a roller press, wherein the pressure of the rolling treatment is controlled to be 10MPa (usually 1-15 MPa); the density of the graphitized graphene composite film is rolled to reach 1.5g/cm³(usually 0.5 to 2.2g/cm³) A thickness of 10 μm (typically 0.5-10 μm); the sheet resistance is 50ohm/sq (usually 1-200ohm/sq), and a graphene hybrid film (namely a rolling heating body film) is prepared;

measuring the density of the prepared graphene hybrid film by adopting a JB/T9141.1-2013 flexible graphite sheet part 1: density test method; measuring the thickness of the graphene hybrid film by using a micrometer with the precision of 0.001 mm; the sheet resistance of the graphene hybrid film was measured using a four-probe sheet resistance tester, and the measurement results are shown in table 1.

Table 1 performance test results of graphene hybrid heating film

	Density (g/cm3)	Thickness (μm)	Square resistance (ohm/sq)
				Example 1	1.5	10	50
Example 2	2.0	9	30
				Example 3	0.5	4	95
Example 4	2.2	6	40
				Comparative example 3	1.7	9	0.5

As is clear from the measurement results in Table 1, the density of the rolled heating element film layer prepared by the method of the present invention is as high as 0.5 to 2.2g/cm³(ii) a The thickness is thin and is only 4-10 mu m; the sheet resistance of the rolled heat-generating body film was large and reached 30 to 95 ohm/sq.

Secondly, preparing a graphene heating body

1. Preparation of graphene hybrid composite membranes

Compounding a rolled heating body film (namely a graphene hybrid film) on a release film through a compound machine to prepare a graphene hybrid combination film, wherein the release film with a release force of 5gf/in (usually 5-20 gf/in) is selected as the release film, and a PET release film, a PP release film or a PE release film and the like are usually selected as the release film;

in the embodiment of the present invention, the release film is PET release film, and other release films known in the art are all suitable for the present invention.

2. Preparation of patterned-graphene hybrid composite films

According to the design requirement that the resistance of a heating element is 300ohm (usually 50-500ohm), punching is carried out by adopting a die cutting machine, patterning treatment (die cutting treatment) is carried out on the surface of the graphene hybrid combination film, and a graphene array with round holes, square holes or strips is formed on the surface of the graphene hybrid combination film, so that the patterned-graphene hybrid combination film 2 is prepared;

the purpose and function of patterning the surface of the graphene hybrid composite film are as follows: 1) the adhesive force between the insulating substrates attached to the two sides of the graphene hybrid composite film is increased after the graphene hybrid composite film is manufactured into a heating body (epoxy glue is connected with the substrates on the two sides of the hybrid composite film through holes, so that the packaging reliability is improved; 2) and regulating and controlling the overall resistance and power of the heating element.

If the graphene is circular hole-shaped graphene, the diameter of each hole is 5mm, and the distance between every two holes is 10 mm; if the graphene is a square hole (square) shaped graphene, the side length of each hole is 5mm, and the hole distance is 10 mm; if the graphene strips are strip-shaped graphene, the width of each graphene strip is 10mm, and the distance between every two graphene strips is 5 mm;

3. first hot pressing

As shown in fig. 1, an adhesive (an epoxy adhesive, which is a high temperature resistant protective adhesive) is pre-coated on a surface of a first heater insulating substrate (an epoxy resin plate) 1, and a patterned-graphene hybrid composite film 2 (a hybrid film layer of the graphene hybrid composite film is bonded to the epoxy resin plate) is bonded to the surface (i.e., the surface on the side of the adhesive) of the heater insulating substrate (the epoxy resin plate) at 100 ℃ (usually 80-120 ℃); performing first hot-pressing treatment in a hot press, and hot-pressing the patterned-graphene hybrid composite membrane to the surface of the heating element insulating substrate by using a hot-pressing method to obtain a first hot-pressing-graphene composite plate, wherein the hot-pressing pressure of the first hot-pressing treatment is 0.7MPa (usually 0.5-0.8 MPa); the first hot pressing temperature is 150 ℃ (typically 120-; the first hot pressing time is 160S (typically 30-240S);

peeling off the release film layer of the first hot-pressing-graphene composite board, and then baking and curing in an oven, wherein the baking and curing temperature is 150 ℃ (usually 120-; or placing in a continuous infrared furnace (IR furnace) at 150 deg.C (usually 120-;

in the embodiment of the invention, the first heater insulating substrate takes an epoxy resin plate as an example, and other materials such as a polyimide film and a mica plate are all suitable for the invention; the first adhesive is a high temperature resistant adhesive (generally, the high temperature resistant performance can reach more than 180 ℃), and besides the high temperature resistant epoxy adhesive, a high temperature resistant silicone adhesive, a high temperature resistant polyimide adhesive, a high temperature resistant phenolic resin adhesive or a high temperature resistant urea-formaldehyde resin adhesive is also suitable for the invention.

4. Printed current-carrying electrode treatment

Respectively printing silver paste on two parallel ends of a graphene hybrid combination film layer of a first graphene assembly by adopting a screen printing method, wherein the thickness of a printed wet film is 30 micrometers (usually 20-60 micrometers), then placing the film into an oven, and performing baking curing treatment at 150 ℃ (usually 130-160 ℃), wherein the curing treatment is performed for 45min (usually 30-60 min); or placing the composite material into an IR (infrared) tunnel furnace, baking and curing at 150 ℃ (usually 130-; the width of the silver paste current-carrying strip electrode is 10mm (usually 5-20 mm), and the thickness of the silver paste current-carrying strip electrode after solidification is 20 μm (usually 15-25 μm); the end of the silver paste current carrying strip electrode is a wiring terminal 4 of a heating element wire, as shown in figure 1.

The silver paste used for printing the silver paste current-carrying strip electrode is high-conductivity silver paste with silver powder granularity of 1-3 mu m and silver powder solid content of more than 70%; silver paste with the thickness of 25 mu m and the sheet resistance of about 10m ohm/sq after curing, and the silver conductive paste known in the prior art is all suitable for the invention.

Binding post is located silver thick liquid current carrying strip electrode end, before the epoxy resin board of second hot pressing, through in advance on the second epoxy resin board corresponding position trompil, counterpoint before the hot pressing, uncover terminal (two), after hot pressing and solidification, can be connected external electric wire and binding post through welding or riveted form.

5. Second hot pressing treatment

Pre-coating an adhesive (epoxy adhesive, which is high-temperature-resistant protective adhesive) on the surface of a second heating element insulating substrate (an epoxy resin plate, wherein a wiring terminal area on the epoxy resin plate is pre-punched by laser or CNC (computerized numerical control), reserving 2 wiring terminal holes), attaching a graphene hybrid combined film layer of a printed electrode-graphene combined body to the surface (namely the surface on one side of the adhesive) of the second heating element insulating substrate (an oxygen resin plate) under the condition of 100 ℃ (usually 80-120 ℃), and ensuring that a silver paste current-carrying bar electrode terminal area corresponds to a pre-punched area on the epoxy resin plate of the second heating element insulating plate; then placing the mixture into a hot press, and carrying out second hot pressing treatment, wherein the pressure of the second hot pressing treatment is 0.7MPa (usually 0.5-0.8 MPa); the second hot pressing temperature is 180 ℃ (typically 120 ℃ -; the second hot pressing time is 160s (typically 30-240 s); then placing the mixture into an oven, and baking and curing the mixture for 90min (usually 80-120min) at the temperature of 150 ℃ (usually 120-; or baking in a continuous infrared furnace (IR furnace) at the speed of 0.5m/min for 40min (30-50min) at the temperature of 150 ℃ (usually 120-.

When the electric heating picture is prepared, the external electric wire is connected with the wiring terminal through the wiring terminal hole reserved by punching in advance in a welding or riveting mode.

The working life test method of the 22-section heater and the measuring method of the electric-thermal radiation conversion efficiency of the 17-section heater in the national standard GB/T7287-.

TABLE 2 results of measuring the Performance of the heating element

	Working life (h)	Electric-thermal radiation conversion efficiencyPercentage (%)
			Example 1	>30000	76％
Example 2	>30000	75％
			Example 3	>30000	72％
Example 4	>30000	73％
			Comparative example 1	5000	60％
Comparative example 2	8000	65％
			Comparative example 3	>30000	68％

Wherein the service life is defined as the time when the final value of the electric-thermal radiation conversion efficiency of the heating body is reduced to 90 percent of the initial value and no damage occurs.

The service life and the electricity-heat conversion efficiency of the electric heating picture are obviously higher than those of the comparison example, namely the electric heating picture has advantages in various performances such as service life, energy conservation, heating effect, far infrared physiotherapy and the like.

Thirdly, preparing the electric heating picture

1. And covering a PET film on the surface of the surface decorative picture 6 by using an adhesive to form a decorative picture protective layer 7.

Besides adopting the adhesive to cover the PET film on the surface of the decorative picture, the invention can also directly spray the curing type UV gloss oil on the surface of the decorative picture, and form the protective layer of the decorative picture through UV light irradiation and curing.

2. An aluminum alloy frame (namely a fixed frame) 8 is adopted to assemble a decorative picture (containing a protective layer), a graphene heating body and a heat preservation layer of the electric heating picture from the outside to the inside to form a complete electric heating picture structure, as shown in figure 2, the total thickness of the electric heating picture is about 1cm, wherein the decorative picture layer, the graphene heating body layer and the heat preservation layer are arranged at intervals, and the distance between every two adjacent layers is 5mm (usually 3-15 mm).

The binding post of the heat-generating body of electric heat picture passes through the wire and sets up external temperature controller on the wire, the wire socket electricity is connected, after the switch on, generates heat through temperature controller control heat-generating body, and graphite alkene heat-generating body launches far infrared to both sides, and the heat preservation ensures that the heat is mainly preserved in heat-generating body and decoration picture one side, has effectively promoted the work efficiency (electricity-heat radiation efficiency) of electric heat picture.

Example 1A

Preparation of graphene hybrid membrane

Same as in example 1

Secondly, preparing a graphene heating body

1. Preparation of graphene hybrid composite membranes

Same as in example 1

2. Patterning process

Same as in example 1

3. First hot pressing

The same as example 1 was conducted, except that a plurality of (13, usually ≧ 3, preferably 5 to 15) patterned graphene composite films were attached to the surface of the heating element substrate epoxy resin plate, and the patterned graphene composite films were parallel to each other and spaced apart from each other by 5mm (usually 2 to 10mm), to form a patterned graphene composite film group, as shown in fig. 1A.

4. Printed current-carrying electrode treatment

The same procedure as in example 1 was repeated except that silver pastes were printed on both parallel ends of a patterned graphene assembly film group composed of a plurality of patterned graphene assembly films parallel to each other and integrally connected to each other

5. Second hot pressing treatment

Same as in example 1

Thirdly, preparing the electric heating picture

Same as in example 1.

Example 2

Preparation of graphene hybrid membrane

Wherein the dispersant is polyvinyl alcohol (PVA); the solvent is N-methylpyrrolidone (NMP);

2. preparation of Heater slurry

The same as in example 1 except that the prepared heat-generating body slurry has a viscosity of 8000cPs (usually 500 to 20000cPs, preferably 2000 to 8000 cPs);

3. preparation of graphene-carbon nanotube composite film

Except that the heating body slurry is coated on the PET release film; the coating thickness is 200 μm (usually 10 to 1000 μm, preferably 50 to 200 μm); the drying temperature is 180 ℃ (usually 90-180 ℃); the drying time is the same as that of the example 1 except that the drying time is 20min (usually 20-30 min);

4. thermal reduction treatment

Except that the thermal reduction temperature is 600 deg.C (typically 500 deg.C and 1000 deg.C); the heating speed of the thermal reduction furnace is 10 ℃/min (usually 4-20 ℃/min); the thermal reduction heat preservation time is 10 hours (usually 3 to 10 hours), and the rest is the same as the example 1;

5. roll-in treatment

Except for the control rollerThe pressure of the press treatment is 15MPa (usually 1-15 MPa); the density of the graphitized graphene composite film is rolled to reach 2.0g/cm³(usually 0.5 to 2.2g/cm³) A thickness of 9 μm (typically 0.5-10 μm); the sheet resistance was the same as that in example 1 except that it was 30ohm/sq (usually 1 to 200 ohm/sq);

the density, thickness and sheet resistance test results of the prepared graphene hybrid film (i.e., the rolled heat-generating body film) are shown in table 1.

Secondly, preparing a graphene heating body

1. Preparation of graphene hybrid composite membranes

The method is the same as that of example 1 except that a PET release film having a release force of 8gf/in (usually 5 to 20gf/in) is selected;

2. preparation of patterned-graphene hybrid composite films

The procedure of example 1 was repeated, except that the patterned graphene hybrid composite film was obtained by punching with a die cutter according to the design requirement of a heating element having a resistance of 200ohm (usually 50 to 500 ohm);

3. first hot pressing

Except that the first heat generator insulating substrate is a mica plate; the pressure of the first hot pressing treatment is 0.5MPa (usually 0.5-0.8 MPa); the hot pressing temperature is 200 ℃ (usually 120 ℃ -; the same procedure as in example 1 was repeated except that the hot pressing time was 240s (usually 30 to 240 s);

4. printed current-carrying electrode treatment

Same as "printed current carrying electrode treatment" of example 1A;

5. second hot pressing treatment

Except that the second heating body insulating board adopts a mica plate; the pressure of the second hot pressing treatment is 0.5MPa (usually 0.5-0.8 MPa); the hot pressing temperature is 200 ℃ (usually 120 ℃ -; the same procedure as in example 1 was repeated except that the hot pressing time was 240s (usually 30 to 240 s);

the working life and the electric-thermal radiation performance of the prepared graphene heating element were tested, and the results are shown in table 2.

Thirdly, preparing the electric heating picture

1. And spraying curing type UV gloss oil on the surface of the decorative picture, and irradiating and curing by UV light to form a decorative picture protective layer 7.

2. On the surface of the insulating layer 9, a layer of pure aluminum foil film is covered on the surface of the insulating layer by an adhesive (high temperature resistant adhesive) to form an infrared reflecting layer 10, and the thickness of the aluminum foil is 100 μm.

In the embodiments of the present invention, the aluminum film layer is taken as an example for illustration, and other film layers made of one or more materials such as silver, copper, Polyethylene (PE), glass fiber, and PET are suitable for use as the infrared reflecting layer of the present invention.

In addition, in this embodiment, the reflective layer is prepared by directly bonding the aluminum thin film by using an adhesive, and the aluminum thin film layer (i.e. the infrared reflective layer 10) with a thickness of 100 μm (usually 0.1 to 1000 μm, preferably 10 to 200 μm) can also be prepared on the surface of the insulating layer glass magnesium plate by one or more of printing, spraying, suspension coating, curtain coating, Chemical Vapor Deposition (CVD) method or PVD (evaporation, sputtering); the heat-insulating layer can also be made of polyurethane heat-insulating plates or extruded plates, and other heat-insulating plates known in the prior art are all suitable for the heat-insulating plate.

3. Assembling a decorative picture (containing a protective layer), a graphene heating element and a heat-insulating layer (containing an infrared reflecting layer) of the electric heating picture from the outside to the inside by adopting an aluminum alloy frame (namely a fixed frame) 8 to form a complete electric heating picture structure, wherein the total thickness of the electric heating picture is about 1cm as shown in figure 3, the decorative picture layer, the graphene heating element layer and the heat-insulating layer are arranged at intervals, and the distance between every two adjacent layers is 5mm (usually 3-15 mm); the infrared reflecting layer faces the graphene heating body.

Example 3

Preparation of graphene hybrid membrane

Wherein the dispersant is Sodium Dodecyl Sulfate (SDS); the solvent is water;

2. preparation of Heater slurry

The same as in example 1 except that the prepared heat-generating body slurry has a viscosity of 500cPs (usually 500 to 20000cPs, preferably 2000 to 8000 cPs);

3. preparation of graphene-carbon nanotube composite film

Same as example 1;

4. thermal reduction treatment

Except that the thermal reduction temperature is 700 ℃ (typically 500 ℃ - & 1000 ℃); the heating speed of the thermal reduction furnace is 4 ℃/min (usually 4-20 ℃/min); the thermal reduction heat preservation time is 10 hours (usually 3 to 10 hours), and the rest is the same as the example 1;

5. roll-in treatment

Except that the pressure of the roll treatment is controlled to be 7MPa (usually 1 to 15 MPa); rolling until the density of the graphitized graphene composite film reaches 0.5g/cm³(usually 0.5 to 2.2g/cm³) A thickness of 4 μm (typically 0.5-10 μm); the sheet resistance was the same as that of example 1 except that it was 95ohm/sq (usually 50-500 ohm/sq);

Secondly, preparing a graphene heating body

1. Preparation of graphene hybrid composite membranes

Same as example 1;

2. preparation of patterned-graphene hybrid composite films

The procedure of example 1 was repeated, except that the patterned graphene hybrid composite film was obtained by punching with a die cutter according to the design requirement of a heating element having a resistance of 500ohm (usually 50 to 500 ohm);

3. first hot pressing

Except that the pressure of the first hot pressing treatment is 0.8MPa (usually 0.5-0.8 MPa); the hot pressing temperature is 120 ℃ (usually 120 ℃ -; the same procedure as in example 1 was repeated except that the hot pressing time was 240s (usually 30 to 240 s);

4. printed current-carrying electrode treatment

Same as "printed current carrying electrode treatment" of example 1A;

5. second hot pressing treatment

Except that the pressure of the second hot pressing treatment is 0.8MPa (usually 0.5-0.8 MPa); the hot pressing temperature is 120 ℃ (usually 120 ℃ -; the same procedure as in example 1 was repeated except that the hot pressing time was 240s (usually 30 to 240 s).

Thirdly, preparing the electric heating picture

1. Mixing infrared-enhanced raw material silicon carbide powder and adhesive water-based epoxy resin, stirring and uniformly dispersing to prepare enhanced layer slurry with the viscosity of 2500cps (usually 1000-10000cps), wherein the weight part ratio of the silicon carbide to the adhesive is 20:80 (usually 10-30:70-90), and the particle size of the silicon carbide powder is 0.1-3 μm, preferably 0.1-0.5 μm; spraying infrared enhancement layer slurry on the side of the graphene heating body layer facing the surface layer decorative picture, then baking for 30min (usually 20-40min) at the temperature of 150 ℃ (usually 120-160 ℃), and curing the slurry to form the infrared enhancement layer 11 with the thickness of 200 μm (usually 0.1-1000 μm, preferably 10-300 μm).

Raw materials of the infrared enhancement layer slurry are other than silicon carbide, and one or more of graphite, micro-nano carbon material, nano silicon powder, metal oxide, silicon carbide, boron carbide, sodium silicate, aluminum silicate, diamond-like carbon, graphene, graphite alkyne, carbon black, carbon nanotube, iron oxide, nickel oxide, chromium oxide, copper oxide, manganese oxide, cobalt oxide or aluminum oxide are suitable for the invention.

The embodiment of the invention takes silicon carbide as an example for illustration, and other materials such as graphene, silicon oxide or graphite are all suitable for the invention; the infrared enhancement layer is prepared by spraying, and besides the spraying, other methods in the field such as printing, spin coating, curtain coating, deposition and the like are all suitable for preparing the infrared enhancement layer.

2. Mixing infrared absorption raw material carbon nanotube powder and adhesive water-based acrylic resin, stirring and dispersing uniformly to prepare reinforcing layer slurry with the viscosity of 1500cps (usually 500-5000cps), wherein the weight part ratio of the carbon nanotube to the adhesive is 15:85 (usually 10-30:70-90), the diameter of the carbon nanotube is 0.005-0.05 μm, and the length of the carbon nanotube is 5-20 μm; spraying infrared absorption layer slurry on the back surface (i.e. the side facing the graphene heating body layer) of the surface layer decorative picture, then baking for 40min (usually 20-40min) at 130 ℃ (usually 120-.

Preparing a carbon nano tube coating on the back surface of a base material of the prepared decorative picture, namely the side facing the graphene heating element, in a coating mode; after curing, an infrared absorbing layer 12 having a thickness of 100 μm (usually 0.1 to 1000 μm) is formed on the back surface of the decorative picture base material.

In the embodiment of the present invention, the infrared absorption layer is prepared by spraying, and besides the spraying, other methods in the art, such as printing, spin coating, curtain coating, deposition, etc., are all suitable for preparing the infrared absorption layer. Besides carbon nanotubes, the infrared absorption raw materials include indium tin oxide, antimony tin oxide, cesium tungsten oxide, tungsten tin oxide, zinc oxide, silicon oxide, aluminum oxide, calcium carbonate, titanium dioxide, wollastonite, silica gel powder, graphite, micro-nano carbon material, nano silicon powder, melamine, polyphenylene sulfide, boric acid, resin, polyethylene wax, zinc stearate, white oil, graphene, graphite alkyne, carbon black or carbon nanotubes; the resin is PP (polypropylene), PET, PC (polychloroprene), ABS (polyacrylonitrile-butadiene-styrene), PMMA (polymethyl methacrylate), PS (polystyrene) or PVC (polyvinyl chloride), which are all suitable for the invention, and carbon nano tubes, graphene or zinc oxide are preferred.

3. And covering a PET film on the surface of the surface decorative picture 6 by using an adhesive to form a decorative picture protective layer 7.

4. And covering a pure aluminum foil film on the surface of the heat-preservation layer glass magnesium board through an adhesive to form an infrared reflecting layer 10, wherein the thickness of the aluminum foil is 100 mu m.

5. Assembling a decorative picture (comprising a protective layer and an infrared absorption layer), a heating body (comprising an infrared enhancement layer) and a heat preservation layer (comprising a reflection layer) of the electric heating picture in sequence by adopting an aluminum alloy fixing frame 8 to form a complete electric heating picture structure, wherein the total thickness of the electric heating picture is about 1cm as shown in figure 4, the decorative picture layer, the graphene heating body layer and the heat preservation layer are arranged at intervals, and the distance between every two adjacent layers is 5mm (usually 3-15 mm); the infrared absorption layer faces the graphene heating body; the infrared enhancement layer faces the decorative picture; the infrared reflecting layer faces the graphene heating body.

Example 4

Preparation of graphene hybrid membrane

2. preparation of Heater slurry

The same as in example 1 except that the prepared heat-generating body slurry has a viscosity of 2000cPs (usually 500 to 20000cPs, preferably 2000 to 8000 cPs);

3. preparation of graphene-carbon nanotube composite film

Except that the drying temperature is 90 ℃ (typically 90 to 180 ℃); the drying time is 30min (usually 20-30 min), and the rest is the same as the example 1;

4. thermal reduction treatment

Except that the thermal reduction temperature is 1000 deg.C (typically 500 deg.C and 1000 deg.C); the heating speed of the thermal reduction furnace is 20 ℃/min (usually 4-20 ℃/min); the thermal reduction heat preservation time is 5 hours (usually 3 to 10 hours), and the rest is the same as the example 1;

5. roll-in treatment

Except that the pressure of the roll treatment is controlled to be 12MPa (usually 1 to 15 MPa); the density of the graphitized graphene composite film is rolled to reach 2.2g/cm³(usually 0.5 to 2.2g/cm³) A thickness of 6 μm (typically 0.5-10 μm); the sheet resistance was the same as that of example 1 except that it was 40ohm/sq (usually 50-500 ohm/sq);

Secondly, preparing a graphene heating body

1. Preparation of graphene hybrid composite membranes

Same as example 1;

2. preparation of patterned-graphene hybrid composite films

3. first hot pressing

Except that the pressure of the first hot pressing treatment is 0.7MPa (usually 0.5-0.8 MPa); the hot pressing temperature is 200 ℃ (usually 120 ℃ -; the same procedure as in example 1 was repeated except that the hot pressing time was 100 seconds (usually 30 to 240 seconds);

4. printed current-carrying electrode treatment

Same as example 1;

5. second hot pressing treatment

Except that the pressure of the second hot pressing treatment is 0.7MPa (usually 0.5-0.8 MPa); the hot pressing temperature is 200 ℃ (usually 120 ℃ -; the same procedure as in example 1 was repeated except that the hot pressing time was 100 seconds (usually 30 to 240 seconds).

Thirdly, preparing the electric heating picture

Same as in example 3.

Comparative example 1

Printing a patterned carbon paste conductive film on the surface of a first heater insulating substrate by adopting a correspondingly designed patterned screen printing screen plate according to the design requirement of a heater resistor (300ohm) and directly adopting a screen printing method, and baking and drying to form a carbon heating film; the carbon heating film formed after baking and drying is firmly combined on the surface of the first heater insulating substrate; then, silver paste is printed at the two parallel ends of the carbon heating film and baked to form silver paste current carrying strip electrodes; then, a second heating element insulating substrate (epoxy resin plate) with the surface coated with high-temperature-resistant protective glue (adhesive) in advance is attached to a first heating element insulating substrate (epoxy resin plate) with the surface prepared with a carbon paste conducting film and a silver paste electrode to form a first heating element insulating plate/carbon paste conducting film-silver paste electrode/second heating element insulating plate assembly; next, the laminated assembly was subjected to a hot press treatment under the same control conditions as the second hot press treatment in example 1, and the obtained heating element was used as comparative example 1; the process control conditions of silver paste printing, silver paste current carrying strip electrode forming and hot pressing are the same as those of the current carrying electrode printing and the second hot pressing in the embodiment 1.

An electric heating picture was prepared in the same manner as in example 1.

Comparative example 2

A carbon heating film which adopts commercial carbon fiber paper (purchased from Jinzhou city, Hongshengda and attached to the surface of a release film) as a heating element; according to the design requirement that the resistance of the heating body is 300ohm, a die cutting machine is adopted for punching, and patterning treatment (die cutting treatment) is carried out on the surface of the carbon fiber paper to prepare the patterned carbon fiber paper. Attaching and hot-pressing patterned carbon fiber paper to the surface of a first insulating plate with the surface coated with a high-temperature-resistant protective adhesive (adhesive) in advance, preparing a corresponding current-carrying silver electrode on the surface of the patterned carbon fiber paper, and hot-pressing the current-carrying silver electrode and the surface of a second insulating plate with the surface coated with the high-temperature-resistant protective adhesive (adhesive) in advance to prepare a heating body as a comparison example 2; the process control conditions of the first hot pressing (patterned carbon fiber paper) treatment process, the silver paste printing process, the silver paste current-carrying bar electrode forming process and the second hot pressing process performed on the surface of the first heater insulating plate are the same as those of the first hot pressing, the current-carrying electrode printing process and the second hot pressing process in embodiment 1.

An electric heating picture was prepared in the same manner as in example 1.

Comparative example 3

The same as example 1 except that the step of preparing the graphene hybrid exothermic film did not contain carbon nanotubes and the amount of graphene oxide used was 25 × 100 g.

The above-described embodiments of the present invention are merely exemplary and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. A preparation method of an electrothermal picture is characterized by comprising the following steps:

2. A preparation method of an electrothermal picture is characterized by comprising the following steps:

3. A preparation method of an electrothermal picture is characterized by comprising the following steps:

4. A preparation method of an electrothermal picture is characterized by comprising the following steps:

5. A preparation method of an electrothermal picture is characterized by comprising the following steps:

6. A preparation method of an electrothermal picture is characterized by comprising the following steps:

7. A preparation method of an electrothermal picture is characterized by comprising the following steps:

8. A preparation method of an electrothermal picture is characterized by comprising the following steps:

9. The method according to any one of claims 1 to 8, wherein the graphene hybrid film in step 1) is prepared by the following steps:

1-1) preparing the following raw materials in parts by weight

10. An electrothermal picture, prepared according to the method of any one of claims 1 to 9.