CN113232374A

CN113232374A - Transparent conductive heating composite material, preparation method thereof and automobile windshield

Info

Publication number: CN113232374A
Application number: CN202110345727.3A
Authority: CN
Inventors: 杜宇; 邓飞; 辛培培; 张玲
Original assignee: Shenzhen Cone Technology Co ltd
Current assignee: Shenzhen Cone Technology Co ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-08-10

Abstract

The invention relates to a transparent conductive heating composite material, a preparation method thereof and an automobile windshield. The preparation method of the transparent conductive heating composite material comprises the following steps: mixing the raw materials for preparing the conductive heating slurry to prepare the conductive heating slurry, wherein the raw materials for preparing the conductive heating slurry comprise a carbon nano tube, a transparent conductive material and a dispersing agent, the length-diameter ratio of the carbon nano tube is 1000-5000, and the mass ratio of the carbon nano tube to the transparent conductive material to the dispersing agent is (2.5-10): (2.5-15): (1-5); preparing a transparent and linear heating circuit on a first transparent substrate by adopting conductive heating slurry; and attaching the second transparent substrate to the first transparent substrate with the heating circuit, wherein the heating circuit is positioned between the first transparent substrate and the second transparent substrate, and preparing the transparent conductive heating composite material. The preparation method of the transparent conductive heating composite material is simple and has low requirements on equipment.

Description

Transparent conductive heating composite material, preparation method thereof and automobile windshield

Technical Field

The invention relates to the technical field of materials, in particular to a transparent conductive heating composite material, a preparation method thereof and an automobile windshield.

Background

If the surface of a common automobile windshield is easily fogged, the visual field of a driver is influenced, and the safety of automobile driving is reduced. Therefore, the existing automobile windshield is not easy to fog by adding a transparent indium tin oxide thin film conducting layer and a transparent heating layer between two pieces of glass.

However, the current method for industrially producing the indium tin oxide film is a magnetron sputtering method, and the preparation of the indium tin oxide film by the magnetron sputtering method depends on a costly magnetron sputtering device and a high-quality target material, so that the cost for preparing the windshield containing the indium tin oxide film is higher.

Disclosure of Invention

Therefore, a method for preparing a transparent conductive heating composite material with low cost is needed.

A preparation method of a transparent conductive heating composite material comprises the following steps:

mixing raw materials for preparing the conductive heating slurry to prepare the conductive heating slurry, wherein the raw materials for preparing the conductive heating slurry comprise carbon nano tubes and transparent conductive materials, and the length-diameter ratio of the carbon nano tubes is 1000-5000;

adopting the conductive heating slurry to form a transparent and linear heating circuit on the surface of the first transparent substrate; and

and (3) attaching a second transparent substrate to the first transparent substrate with the heating circuit, wherein the heating circuit is positioned between the first transparent substrate and the second transparent substrate, so as to prepare the transparent conductive heating composite material.

After a mold with a preset hollow pattern is placed on the first transparent substrate, coating the conductive heating slurry on the mold so as to fill the conductive heating slurry into the mold;

baking the conductive heating slurry in the mold to completely volatilize the organic solvent in the conductive heating slurry; and

and after the baking is finished, removing the die to obtain a first transparent substrate on which the transparent linear heating circuit is formed.

In one embodiment, the step of preparing the transparent and linear heat-generating circuit includes:

In one embodiment, the mold is made of polytetrafluoroethylene sheets, and the thickness of the mold is 10-20 μm.

In one embodiment, the hollow part of the hollow pattern of the mold is linear with a width of 2mm to 10 mm.

In one embodiment, the hollow parts of the hollow pattern of the mold are in a reciprocating folding structure.

In one embodiment, the conductive heating paste further includes a dispersant and an organic solvent, and the mass ratio of the carbon nanotubes to the transparent conductive material, the dispersant and the organic solvent is (2.5-10): (2.5-15): (1-5): (70-96).

In one embodiment, the transparent conductive material is selected from at least one of poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonic acid, polyacetylene, polyaniline, polypyrrole, polythioether and polyparaphenylene.

In one embodiment, the first transparent substrate and the second transparent substrate are made of glass, and before the step of attaching the second transparent substrate to the first transparent substrate on which the heating circuit is prepared, a step of laying an adhesive layer on the side of the first transparent substrate on which the heating circuit is arranged is further included.

In one embodiment, the thickness of the bonding layer is 0.4 mm-2.4 mm;

and/or the material of the bonding layer is selected from at least one of polyvinyl butyral and ethylene-vinyl acetate copolymer.

In one embodiment, before the step of attaching the second transparent substrate to the first transparent substrate on which the heat-generating circuit is prepared, a step of preparing a conductive member electrically connected to the heat-generating circuit is further included.

The preparation method of the transparent conductive heating composite material can be prepared by coating the conductive heating slurry on the first transparent substrate and then baking, so that the use of the conductive heating slurry is saved, the dependence on expensive equipment and high-quality target materials is not required, and the manufacturing cost is reduced. And according to the difference of the heating part needed in use, different glass with linear heating circuits can be prepared by only selecting a proper mould, so that local heating is realized, and the use of excessive conductive heating slurry or higher voltage is avoided. In addition, the transparent conductive heating composite material prepared by the preparation method of the transparent conductive heating composite material is high in light transmittance and high in heating efficiency.

The utility model provides a transparent conductive heating composite material, transparent conductive heating composite material includes first transparent base member, second transparent base member and is located transparent and the threadiness heating circuit that is between first transparent base member and the second transparent base member, the heating circuit is made by electrically conductive heating slurry, electrically conductive heating slurry includes carbon nanotube, transparent conducting material and dispersant, carbon nanotube's draw ratio is 1000 ~ 5000, carbon nanotube with transparent conducting material with the quality of dispersant compares (2.5 ~ 10): (2.5-15): (1-5).

An automobile windshield is prepared from the transparent conductive heating composite material prepared by the preparation method of the transparent conductive heating composite material.

Drawings

Fig. 1 is a flow chart illustrating a process for preparing a transparent conductive exothermic composite according to an embodiment;

FIG. 2 is a top view of a first transparent substrate prepared with a heating circuit and a conductive member;

fig. 3 is a partial cross-sectional view of an embodiment of a transparent conductive exothermic composite.

Reference numerals:

10. a transparent conductive exothermic composite; 110. a first transparent substrate; 120. a second transparent substrate; 130. a heating circuit; 140. a bonding layer; 150. a conductive member; 200. a mold; 300. conductive heating slurry.

Detailed Description

The present invention will now be described more fully hereinafter for purposes of facilitating an understanding thereof, and may be embodied in many different forms and are not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. When the terms "vertical," "horizontal," "left," "right," "upper," "lower," "inner," "outer," "bottom," and the like are used to indicate an orientation or positional relationship, it is for convenience of description only based on the orientation or positional relationship shown in the drawings, and it is not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Referring to fig. 1 and fig. 2, an embodiment of the present invention provides a method for preparing a transparent conductive heating composite material 10, which includes steps a to c, specifically:

step a: the raw materials for preparing the conductive heating paste 300 are mixed to prepare the conductive heating paste 300.

Specifically, the raw materials for preparing the conductive heating paste 300 include carbon nanotubes, a transparent conductive material and a dispersant, and the mass ratio of the carbon nanotubes to the transparent conductive material to the dispersant is (2.5-10): (2.5-15): (1-5).

The carbon nanotubes serve as a heat generating material in the above conductive heat generating paste 300. The length-diameter ratio of the carbon nano tube is set to be 1000-5000, so that the carbon nano tube can be well dispersed in the conductive heating slurry 300, and can be better bridged and overlapped into a network shape after being dispersed, thereby being beneficial to transfer and transmission of electric charges and improving the heating efficiency of the transparent heating layer 130. In an alternative specific example, the carbon nanotube has an aspect ratio of 1000, 1200, 1500, 1800, 2000, 2200, 2500, 2800, 3000, 3200, 3500, 3800, 4000, 4200, 4500, 4800, or 5000. Further, the length-diameter ratio of the carbon nano tube is 3000-5000. It should be noted that, the aspect ratio of the carbon nanotube herein refers to the ratio of the length to the outer diameter of the carbon nanotube.

In some embodiments, the carbon nanotubes have a tube diameter of 6nm to 10 nm. The carbon nano tubes with the tube diameters distributed in the range have better consistency, and are favorable for improving the conductive stability. In an alternative specific example, the carbon nanotubes have a diameter of 6nm, 6.5nm, 7nm, 7.5nm, 8nm, 8.5nm, 9nm, or 10 nm. Further, the diameter of the carbon nanotube is 8nm to 10 nm. It should be noted that the tube diameter of the carbon nanotube herein refers to the outer diameter of the carbon nanotube.

The transparent conductive material serves as a conductive substance in the conductive heat emitting paste 300, so that the carbon nanotube can be electrically connected to a power supply to emit heat. Optionally, the transparent conductive material is a transparent conductive organic. The transparent conductive organic substance has a certain viscosity, which is beneficial to the adhesion between the transparent heating layer and the first transparent substrate 110 and the second transparent substrate 120. In addition, compared with other transparent conductive materials, the transparent conductive organic matter has high conductivity, can form a conjugate effect with the carbon nano tube to cause the change of the electron cloud density between the transparent conductive layer and the carbon nano tube, is beneficial to the improvement of the conductive performance of the transparent conductive layer, and simultaneously forms a chemical connection with smaller contact resistance, and can promote the improvement of the conductive performance of the carbon nano tube, so that the heat production requirement of anti-fogging can be met by adding a small amount of carbon nano tube, and the anti-fogging function is realized; and because the content of the carbon nano tube is lower, a network structure is formed in the transparent heating layer 130, a new conductive channel is formed, the conductivity and the transparency of the transparent heating layer 130 are also effectively improved, and the transparent heating layer 130 obtained by curing has high transparency and heating stability. In an alternative specific example, the transparent conductive material is selected from at least one of poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonic acid, polyacetylene, polyaniline, polypyrrole, polythioether and polyparaphenylene. Of course, in other embodiments, the transparent conductive material is not limited to the above, and may be other transparent and conductive substances.

The dispersant plays a role of dispersing in the above composition, so that the carbon nanotubes and the transparent conductive material are uniformly dispersed in the prepared conductive heat emitting paste 300. Optionally, the dispersant is selected from at least one of polyvinylpyrrolidone, carboxymethyl cellulose, ethyl cellulose, and nanocellulose. Of course, the dispersant is not limited to the above, and may perform a dispersing function without affecting the heat generation efficiency and light transmittance of the transparent heat generation layer manufactured using the above conductive heat generation paste 300.

Further, the mass ratio of the carbon nano tube to the transparent conductive material to the dispersant is (5.5-10): (10-15): (1-5). The carbon nanotubes are easy to agglomerate, if the carbon nanotubes cannot be sufficiently dispersed, the contact area of the carbon nanotubes and the transparent conductive material is limited, so that the final contact resistance is large, the carbon nanotubes are agglomerated together, the transparency is reduced, the heat is not uniform, and the final conductive heating capacity is low. The mass ratio of the carbon nano tube to the transparent conductive material to the dispersing agent is set according to the above, so that the carbon nano tube and the transparent conductive material are uniformly dispersed in the system respectively, and the electric charge is favorably transported between the carbon nano tube and the transparent conductive material, so that the light transmittance and the heating capacity of the conductive heating slurry 300 can be ensured when the conductive heating slurry is used, and the rapid heating can be realized only by using lower heating power while the high definition of the conductive heating slurry is maintained. Meanwhile, the content of the carbon nanotubes is moderate under the proportion, and on the premise of complete dispersion, the conductive heating slurry 300 is favorable for flowing and forming, so that the transparent heating layer cannot be formed due to over-dilution, and the conductive heating slurry 300 is difficult to fill a mold due to over-thickening. Furthermore, the mass ratio of the carbon nano tube to the transparent conductive material to the dispersant is (5.5-10): (12-15): (1-5).

Of course, the conductive heat emitting paste 300 further includes an organic solvent. Optionally, the organic solvent is at least one of ethylene glycol, butyl glycol ether, and propylene glycol methyl ether. The mass ratio of the carbon nano tube to the transparent conductive material, the dispersant and the organic solvent is (2.5-5): (2.5-15): (1-5): (70-96). In an optional specific example, the conductive heating paste 300 is composed of carbon nanotubes, a transparent conductive material, a dispersant and an organic solvent, wherein the mass ratio of the carbon nanotubes to the transparent conductive material, the dispersant and the organic solvent is (2.5-5): (2.5-15): (1-5): (70-96), the diameter of the carbon nano tube is 6-10 nm. Further, the mass ratio of the carbon nanotubes to the transparent conductive material, the dispersant and the organic solvent is (5.5-10): (12-15): (1-5): (80-90).

The conductive heating paste 300 can ensure that the heating circuit 130 prepared from the conductive heating paste 300 has high heating efficiency and high light transmittance through the matching of the carbon nano tube, the transparent conductive material and the dispersing agent, so that the glass containing the heating circuit 130 is not easy to fog, and has good light transmittance, high safety and low energy consumption.

Step b: the conductive heating paste 300 is used to form the transparent and linear heating circuit 130 on the surface of the first transparent substrate 110.

Alternatively, the material of the first transparent substrate 110 is selected from one of glass and transparent resin. In an alternative specific example, the material of the first transparent substrate 110 is tempered glass or semi-tempered glass. Of course, in other embodiments, the material of the first transparent substrate 110 is not limited to the above, and may be other transparent materials.

In the present embodiment, the first transparent substrate 110 is sheet-shaped; the thickness of the first transparent substrate 110 is 3mm to 5 mm. Of course, in other embodiments, the shape of the first transparent substrate 110 is not limited to a sheet shape, but may be any other shape; the thickness of the first transparent substrate 110 is not limited to the above, and can be adjusted according to actual requirements.

Specifically, the step of forming the transparent and linear heating circuit 130 by routing the conductive heating paste 300 on the surface of the first transparent substrate 110 includes: placing a mold 200 with a preset hollow pattern on the first transparent substrate 110, and then coating the conductive heating paste 300 thereon, so that the conductive heating paste 300 forms a heating circuit 130 with a corresponding hollow pattern on the surface of the first transparent substrate 110 through the hollow pattern of the mold 200; baking the conductive heating paste 300 in the mold 200 to completely volatilize the organic solvent in the conductive heating paste 300; and removing the mold 200 after the baking is finished to obtain the first transparent substrate 110 printed with the heating circuit 130 with the hollow pattern. The heating circuit 130 is prepared by the mold 200 with the preset hollow pattern, so that the thickness uniformity of the heating circuit 130 can be improved, and the heating uniformity is improved.

Optionally, the mold 200 is a teflon sheet with a preset hollow pattern; the thickness of the mold 200 is 10 μm to 20 μm; the hollow part of the hollow pattern of the mold 200 is linear with a width of 2mm to 10 mm. Further, the hollow pattern of the mold 200 is a reciprocating folding structure. In one specific example, the hollow pattern of the mold 200 is a continuous "zigzag" shape. Of course, the material of the mold 200 is not limited to teflon, but may be other materials; the thickness of the mold 200 is not limited to the above, and may be adjusted according to actual requirements. It can be understood that the predetermined hollow pattern of the mold 200 is designed according to the shape of the heat-generating circuit 130 to be manufactured. It can be understood that, the conductive heating paste 300 is filled into the preset mold 200, and after the baking is finished, the heating circuit 130 is just filled inside the hollow part of the mold due to the volatilization of the organic solvent. At this time, the cured conductive heat emitting paste remaining on the mold 200 is also removed along with the removal of the mold.

Optionally, the baking temperature is 50-70 ℃; the baking time is 50-60 min. The conductive heating slurry 300 is baked according to the parameters, the proper baking temperature and baking time are adopted, so that the solvent of the conductive heating slurry 300 can be completely volatilized, the transparent heating layer is uniformly laid on the first transparent base body, the defect of the inside of the transparent heating layer caused by the too fast volatilization of the solvent can not be caused, the combination stability of the carbon nano tube and the transparent conductive polymer is poor, and the problem of the conductive heating capacity of the final heating circuit 130 is influenced.

Step c: the second transparent substrate 120 is attached to the first transparent substrate 110 with the heating circuit 130, and the heating circuit 130 is located between the first transparent substrate 110 and the second transparent substrate 120, so as to prepare the transparent conductive heating composite material 10.

Alternatively, the material of the second transparent substrate 120 is selected from one of glass and transparent resin. In an alternative specific example, the material of the second transparent substrate 120 is tempered glass or semi-tempered glass. Of course, in other embodiments, the material of the second transparent substrate 120 is not limited to the above, and may be other transparent materials.

In the present embodiment, the transparent conductive heat emitting composite 10 further includes a conductive member 150 for electrical connection with a power source. Therefore, before the second transparent substrate 120 is attached to the first transparent substrate 110 with the heating circuit 130, a step of preparing the conductive member 150 on the first transparent substrate 110 is further included. Alternatively, the conductive member 150 includes two conductive units spaced apart from each other in a line shape, and one end of each of the two conductive units is connected to the heat generating circuit 130, and the other end of each of the two conductive units is electrically connected to a power supply to form a loop. The two conductive units may be located on the same side of the heating circuit 130, or may be located on two opposite sides of the heating circuit 130.

In one embodiment, conductive member 150 is made of conductive paste (e.g., conductive silver paste). At this time, the step of preparing the conductive member 150 includes: coating conductive paste on the first transparent substrate 110 provided with the heating circuit 130 according to a predetermined shape, and connecting the conductive paste with the heating circuit 130 so that the conductive member 150 can be electrically connected with the heating circuit 130; and baking the conductive paste to prepare the conductive member 150. Optionally, the baking temperature is 70-80 ℃; the baking time is 50-70 min. Baking the conductive paste according to the above parameters can make the conductive member 150 stably connected to the heating circuit 130, and is not easily loosened during subsequent processing and use. The shape of the conductive member 150, the composition of the conductive paste, and the thickness of the coating are not particularly limited. It is understood that in some embodiments, the baking steps for preparing the heat generating circuit 130 and preparing the heat conductive member may be combined. That is, the conductive heating paste 300 and the conductive paste are coated on the first transparent substrate 110, and then the first transparent substrate 110 coated with the conductive heating paste 300 and the conductive paste is baked, thereby preparing the heating circuit 130 and the conductive device 150.

In another embodiment, conductive member 150 is a wire. Such as copper wire, silver wire, etc. Further, the conductive member 150 is a metal wire having a diameter of 0.2mm to 0.7 mm. The conductive member 150 is electrically connected to the heating circuit 130. At this time, after the heat generating circuit 130 is prepared, it is cooled, and then the wire is connected (e.g., soldered) to the heat generating circuit 130.

In the present embodiment, the second transparent substrate 120 is also a glass substrate, and the step of bonding the second transparent substrate 120 to the first transparent substrate 110 on which the heat-generating circuit 130 is formed further includes a step of laying the adhesive layer 140 on the side of the first transparent substrate 110 on which the heat-generating circuit 130 is provided. By laying the adhesive layer 140, the first transparent substrate 110, the heating circuit 130, and the second transparent substrate 120 can be integrally fixed by the adhesive layer 140. Optionally, the thickness of the bonding layer 140 is 0.4mm to 2.4 mm; the material of the adhesive layer 140 is at least one selected from the group consisting of polyvinyl butyral and ethylene-vinyl acetate copolymer.

Specifically, when the first transparent substrate 110 and the second transparent substrate 120 are made of glass, the step of attaching the second transparent substrate 120 to the first transparent substrate 110 on which the heating circuit 130 is prepared includes: an adhesive layer 140 is laid on one side of the first transparent substrate 110, on which the heating circuit 130 is arranged; the second transparent substrate 120 is placed on the bonding layer 140, and the first transparent substrate 110 and the second transparent substrate 120 are bonded by using a molding process to prepare the transparent conductive heating composite material 10. Alternatively, the molding process is autoclave molding or extrusion molding. In a specific example, the molding process is autoclave molding, wherein the molding conditions are that the temperature is 50 ℃ to 80 ℃ and the pressure is 0.6MPa to 0.9 MPa. Of course, the molding process is not limited to the above, and may be other molding processes commonly used in the art.

The preparation method of the transparent conductive heating composite material 10 is simple and direct, does not depend on expensive magnetron sputtering equipment and high-quality target materials, can avoid high equipment and material investment, and is high in light transmittance and heating efficiency of the transparent conductive heating composite material 10 prepared by the preparation method.

Referring to fig. 3, an embodiment of the present invention further provides a transparent conductive heating composite material 10, and the transparent conductive heating composite material 10 is prepared without depending on a magnetron sputtering apparatus and a high-quality target material, has high heating efficiency and high light transmittance, and is not easily fogged when applied to an environment with a large temperature difference (e.g., an inside and outside environment of an automobile in winter).

Specifically, the transparent conductive heating composite material 10 includes a first transparent substrate 110, a second transparent substrate 120, and a transparent and linear heating circuit 130 located between the first transparent substrate 110 and the second transparent substrate 120, wherein the heating circuit 130 is made of the conductive heating paste 300.

Alternatively, the material of the first transparent substrate 110 is selected from one of glass and transparent resin. Alternatively, the material of the second transparent substrate 120 is selected from one of glass and transparent resin. In an alternative specific example, the material of the first transparent substrate 110 and the second transparent substrate 120 are both glass. Of course, in other embodiments, the materials of the first transparent substrate 110 and the second transparent substrate 120 are not limited to the above, and may be other transparent materials.

In the present embodiment, the first transparent substrate 110 is sheet-shaped; the second transparent substrate 120 is also sheet-shaped. The thickness of the first transparent substrate 110 is 3mm to 5 mm; the thickness of the second transparent substrate 120 is 3mm to 5 mm. Of course, in other embodiments, the shape of the first transparent substrate 110 and the second transparent substrate 120 is not limited to a sheet shape, and may be any other shape; the thicknesses of the first transparent substrate 110 and the second transparent substrate 120 are not limited to the above, and may be adjusted according to actual requirements.

Optionally, the heating circuit 130 is in a reciprocating folded configuration. By setting the heating circuit 130 to be a reciprocating folding structure, heating can be more uniform, heating concentration in the central area can be avoided, and meanwhile, the light transmittance can be further improved. In one particular example, the heating circuit 130 is in a continuous S-shape. Of course, the shape of the heat generating circuit 130 is not limited to the above, and may be other patterned lines.

Optionally, the thickness of the heating circuit 130 is 10 μm to 20 μm; the width of the heating circuit 130 is 2mm to 10 mm. Further, the thickness of the heating circuit 130 is 15 μm to 20 μm; the width of the heating circuit 130 is 4mm to 8 mm. The thickness of the heating circuit 130 is set according to the above, so that the transparent conductive heating composite material 10 can ensure qualified heating capacity, the heating capacity is not required to be met by increasing the thickness of the heating circuit 130, and the heating circuit is not easy to deform in subsequent processing; the width of the heating circuit 130 is set as described above so that the transparent conductive heating composite material 10 can further improve transparency. It should be noted that the region where the heating circuit 130 is located may be a part of the transparent conductive heating composite material 10. For example, the plurality of heating circuits 130 are disposed on the first transparent substrate 110 at intervals, and the plurality of heating circuits 130 are electrically connected through the transparent conductive circuit, so that the transparent conductive heating composite material 10 has a defogging/frosting function through the cooperation of the plurality of heating circuits 130. Alternatively, only a partial region of the entire transparent conductive heat emitting composite 10 needs defogging/frosting, and in this case, the heat emitting circuit 130 is disposed only in the region. Of course, the heating circuit 130 may be disposed on the whole transparent conductive heating composite material 10 according to actual requirements.

In the illustrated embodiment, the transparent conductive heat emitting composite 10 further includes a bonding layer 140. The adhesive layer 140 is located between the first transparent substrate 110 and the second transparent substrate 120, the heat generating circuit 130 is embedded in the adhesive layer 140, and the adhesive layer 140 is used for fixing the first transparent substrate 110 and the second transparent substrate 120. Optionally, the thickness of the adhesive layer 140 is 0.4mm to 2.4 mm. The material of the adhesive layer 140 is at least one selected from the group consisting of polyvinyl butyral (PVB) and Ethylene Vinyl Acetate (EVA). It is understood that in some embodiments, the adhesive layer 140 may be omitted. For example, when the first transparent substrate 110 and the second transparent substrate 120 are made of transparent resin, the first transparent substrate 110, the heating circuit 130, and the second transparent substrate 120 may be fixed integrally by hot press molding. Of course, when the material of the first transparent substrate 110 and the second transparent substrate 120 is a transparent material having poor thermal plasticity such as glass, the first transparent substrate 110, the heating circuit 130, and the second transparent substrate 120 may be fixed by another fixing structure in a manner of being stacked in order. Note that, the thickness of the bonding layer 140 herein refers to a distance between the first transparent substrate 110 and the second transparent substrate 120.

In some embodiments, the transparent conductive heating composite material 10 further comprises a conductive member 150 for connecting to a power source, wherein the conductive member 150 is electrically connected to the heating circuit 130. Alternatively, conductive member 150 is made of conductive paste containing a conductive material. In one specific example, the conductive paste is a conductive silver paste. Of course, conductive member 150 may also be a wire; such as copper wire, silver wire, etc. Further, the diameter of the metal wire is 0.2mm to 0.7 mm. Alternatively, the conductive member 150 includes two conductive units spaced apart from each other in a line shape, and one end of each of the two conductive units is connected to the heat generating circuit 130, and the other end of each of the two conductive units is electrically connected to a power supply to form a loop. The two conductive units may be located on the same side of the heating circuit 130, or may be located on two opposite sides of the heating circuit 130. It is understood that in some embodiments, conductors 150 may be omitted. At this time, the conductive member 150 is externally connected when in use.

The heating circuit 130 of the transparent conductive heating composite material 10 is in a transparent line shape by using the heating circuit 130 between the first transparent substrate 110 and the second transparent substrate 120, the line-shaped heating circuit 130 can achieve a better heating effect with less material, the heating uniformity is better, and the light transmittance is better due to the material and the line-shaped distribution of the heating circuit 130; meanwhile, the heating circuit 130 of the transparent conductive heating composite material 10 can be prepared by coating and baking, does not depend on expensive magnetron sputtering equipment and high-quality targets, and is low in manufacturing cost.

The transparent conductive heating composite material has the advantages of low possibility of fogging, high light transmittance, high heating efficiency, low energy consumption and light weight, so that the transparent conductive heating composite material can be applied to the process of automobile manufacturing. Therefore, an embodiment of the present invention further provides an application of any one of the above transparent conductive exothermic composite materials in manufacturing an automobile.

In particular to application of the transparent conductive heating composite material in preparing automobile windshields. It can be understood that the application of the transparent conductive heating composite material is not limited to the automobile field, and can also be applied to the fields with certain requirements on fog prevention and light transmittance.

The invention further provides an automobile windshield which is made of any one of the transparent conductive heating composite materials.

In one embodiment, the automobile windshield is curved glass and comprises a first transparent substrate, a second transparent substrate and a transparent linear heating circuit positioned between the first transparent substrate and the second transparent substrate.

The automobile windshield is made of the transparent conductive heating composite material, is not easy to fog, has high light transmittance, high safety, low energy consumption and low manufacturing cost, and has good application prospect.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The following detailed description is given with reference to specific examples. The following examples are not specifically described, and other components except inevitable impurities are not included. Reagents and instruments used in the examples are all conventional in the art and are not specifically described. The experimental procedures, in which specific conditions are not indicated in the examples, were carried out according to conventional conditions, such as those described in the literature, in books, or as recommended by the manufacturer. In the following examples and comparative examples, unless otherwise specified, the transparent conductive organic material was poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT/PSS), the dispersant was nanocellulose, and the organic solvent was ethylene glycol.

Example 1

The structure of the transparent conductive heating composite material of the embodiment is shown in fig. 3, and is composed of a first transparent substrate, a bonding layer, a heating circuit and a second transparent substrate, wherein the first transparent substrate and the second transparent substrate are both glass substrates, the bonding layer is made of PVB, the heating circuit is in a zigzag pattern (as shown in fig. 3) and is embedded in the bonding layer, and the conductive heating slurry for preparing the heating circuit is composed of carbon nanotubes, transparent conductive organic matters, a dispersing agent and an organic solvent, wherein the diameter of the carbon nanotubes is 10nm, and the mass ratio of the carbon nanotubes to the transparent conductive organic matters to the dispersing agent to the organic solvent is 5.5: 10: 5: 79.5; the thickness of the first transparent substrate is 5mm, the thickness of the heating circuit is 10 μm, the width of the lines of the heating circuit is 6mm, the interval of the lines in the heating circuit is 30mm, the thickness of the bonding layer is 0.4mm, and the thickness of the second transparent substrate is 5 mm.

The preparation method of the transparent conductive heating composite material of the embodiment includes, but is not limited to, the following steps:

(1) preparing conductive heating slurry: mixing the carbon nano tube, the transparent conductive organic matter, the dispersing agent and the organic solvent, and mechanically stirring and uniformly dispersing to prepare the conductive heating slurry. Wherein the diameter of the carbon nano tube is 10nm, and the mass ratio of the carbon nano tube, the transparent conductive organic matter, the dispersing agent and the organic solvent is 5.5: 10: 5: 79.5.

(2) coating the conductive heating slurry prepared in the step (1) on the surface of a polytetrafluoroethylene die with the thickness of 12 microns, wherein the hollowed-out pattern of the die is a continuous zigzag pattern (shown in figure 3), the width of the zigzag pattern is 6mm, the interval is 30mm, and then placing the die into an oven for baking at 50 ℃ for 40min to form a heating circuit after the solvent in the slurry is completely volatilized.

(3) After the mold is removed, PVB with the thickness of 0.4mm is paved and pasted on the heating circuit, a second transparent substrate is placed on the heating circuit, a sandwich structure with the heating circuit positioned between the first transparent substrate and the second transparent substrate is prepared, then, the sandwich structure is molded through an autoclave molding process, and the transparent conductive heating composite material is prepared, wherein in the autoclave molding process, the temperature is 80 ℃, and the pressure is 0.8 MPa.

Example 2

The structure and the manufacturing method of the transparent conductive heat emitting composite of the present embodiment are substantially the same as those of embodiment 1, except that the coating thickness of the conductive heat emitting paste for manufacturing the heat emitting circuit of the transparent conductive heat emitting composite of the present embodiment is different from that of embodiment 1, the coating thickness (thickness of the mold) of the conductive heat emitting paste of the present embodiment is 15 μm, and the thickness of the heat emitting circuit of the present embodiment is 13 μm.

Example 3

The structure and the manufacturing method of the transparent conductive heat emitting composite of the present embodiment are substantially the same as those of embodiment 1, except that the coating thickness of the conductive heat emitting paste for manufacturing the heat emitting circuit of the transparent conductive heat emitting composite of the present embodiment is different from that of embodiment 1, the coating thickness (thickness of the mold) of the conductive heat emitting paste of the present embodiment is 20 μm, and the thickness of the heat emitting circuit of the present embodiment is 18 μm.

Example 4

The structure and the preparation method of the transparent conductive heating composite material of the present embodiment are substantially the same as those of embodiment 2, except that the composition of the conductive heating slurry for preparing the heating circuit of the transparent conductive heating composite material of the present embodiment is different from that of embodiment 2, and the conductive heating slurry of the present embodiment is composed of carbon nanotubes, a transparent conductive organic substance, a dispersant and an organic solvent, wherein the diameter of the carbon nanotubes is 10nm, and the mass ratio of the carbon nanotubes, the transparent conductive organic substance, the dispersant and the organic solvent is 2.5: 2.5: 1: 94.

example 5

The structure and the preparation method of the transparent conductive heating composite material of the present embodiment are substantially the same as those of embodiment 2, except that the composition of the conductive heating slurry for preparing the heating circuit of the transparent conductive heating composite material of the present embodiment is different from that of embodiment 2, and the conductive heating slurry of the present embodiment is composed of carbon nanotubes, a transparent conductive organic substance, a dispersant and an organic solvent, wherein the diameter of the carbon nanotubes is 10nm, and the mass ratio of the carbon nanotubes, the transparent conductive organic substance, the dispersant and the organic solvent is 10: 15: 5: 70.

example 6

The structure and the preparation method of the transparent conductive exothermic composite material of the present embodiment are substantially the same as those of embodiment 2, and the difference is that the hollow pattern of the mold in the present embodiment is also a continuous zigzag pattern, but the zigzag pattern has a width of 6mm and an interval of 20 nm. The width of the line of the heat generating circuit of this embodiment is 6mm, and the interval of the wiring in the heat generating circuit is 20 mm.

Example 7

The structure and the preparation method of the transparent conductive exothermic composite material of the present embodiment are substantially the same as those of embodiment 2, and the difference is that the hollow pattern of the mold in the present embodiment is also a continuous zigzag pattern, but the zigzag pattern has a width of 8mm and an interval of 30 nm. The width of the line of the heat generating circuit of this embodiment is 8mm, and the interval of the wiring in the heat generating circuit is 30 mm.

Comparative example 1

The structure and the preparation method of the transparent conductive heat emitting composite material of the present comparative example are substantially the same as those of example 2, except that in the present comparative example, the aspect ratio of the carbon nanotube is 300.

Comparative example 2

The structure and the preparation method of the transparent conductive heat emitting composite material of this comparative example are substantially the same as those of example 2, except that in this comparative example, the aspect ratio of the carbon nanotube is 8000.

Comparative example 3

The structure and the preparation method of the transparent conductive heating composite material of the comparative example are substantially the same as those of the example 2, and the difference is that in the comparative example, before the heating circuit is prepared on the first transparent substrate, an indium tin oxide film with the thickness of 50 microns is prepared on the first transparent substrate in a magnetron sputtering mode, and then the heating circuit with the same structure and material as those of the example 2 is prepared on the indium tin oxide film; in addition, the conductive heating paste of the comparative example does not include a transparent conductive organic matter, but is formed by uniformly mixing the carbon nanotube, the dispersant and the organic solvent, wherein the mass ratio of the carbon nanotube, the dispersant and the organic solvent is 5.5: 5: 79.5.

comparative example 4

The structure and the preparation method of the transparent conductive heating composite material of the present comparative example are substantially the same as those of example 2, except that the composition of the conductive heating slurry for preparing the heating circuit of the transparent conductive heating composite material of the present comparative example is different from that of example 2, and the conductive heating slurry of the present comparative example is composed of a carbon nanotube, a transparent conductive organic substance, a dispersant and an organic solvent, wherein the diameter of the carbon nanotube is 10nm, and the mass ratio of the carbon nanotube, the transparent conductive organic substance, the dispersant and the organic solvent is 1: 2: 1: 96.

comparative example 5

The structure and the preparation method of the transparent conductive heating composite material of the present comparative example are substantially the same as those of example 2, except that the composition of the conductive heating slurry for preparing the heating circuit of the transparent conductive heating composite material of the present comparative example is different from that of example 2, and the conductive heating slurry of the present comparative example is composed of a carbon nanotube, a transparent conductive organic substance, a dispersant and an organic solvent, wherein the diameter of the carbon nanotube is 10nm, and the mass ratio of the carbon nanotube, the transparent conductive organic substance, the dispersant and the organic solvent is 15: 30: 5: 50.

testing

The transparent conductive heat emitting composites of each example and comparative example were measured for light transmittance using an LS116 glass transmittance tester, and the results are shown in table 1.

And (3) heating test:

the transparent conductive heating composite materials of the examples and the comparative examples were applied with a direct current voltage of 5V, and were all at room temperature before application, and the temperature of the center point of the transparent conductive heating composite materials was 25 ℃. After 5 minutes of electrification, the temperature of the central point of the outer surface of the transparent conductive heating composite material was measured, and the results are shown in table 1.

And (3) defrosting test:

the transparent conductive heating composite materials of the examples and the comparative examples are placed in a low-temperature test box, the environment is frozen at the temperature of 18 ℃ below zero for more than 5 hours, pure water is sprayed for 30 minutes, and the water spraying amount is 5mL/cm²Then, direct current was applied for 20min, and the defrosting effect was observed, and the results are shown in table 1.

TABLE 1

As can be seen from table 1, the light transmittance of the transparent conductive heating composite materials of examples 1 to 7 is more than 75%, which is higher than the standard that the visible light transmittance specified by the national GB9656-2016 safety standard should be not less than 70%, and the defogging/frosting effect is good. It can be seen from example 2 and comparative examples 1 and 2 that when the aspect ratio of the carbon nanotubes is less than 1000 or more than 5000, the heat generating effect of the prepared transparent conductive heat generating composite material is poor. It can be known from example 2 and comparative example 3 that the transparent conductive heating composite material prepared by directly coating the conductive heating slurry on the transparent substrate has a simple preparation process and does not depend on a magnetic control detection device, the prepared transparent conductive heating composite material has better heating effect and better light transmittance, and the composition of the conductive heating slurry has larger influence on the heating effect and the light transmittance by example 2, comparative example 4 and comparative example 5.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The preparation method of the transparent conductive heating composite material is characterized by comprising the following steps of:

preparing a transparent and linear heating circuit on the surface of the first transparent substrate by adopting the conductive heating slurry; and

2. The method for preparing a transparent conductive heating composite material according to claim 1, wherein the step of preparing a transparent and linear heating circuit comprises:

3. The method for preparing a transparent conductive exothermic composite according to claim 2, wherein the mold is a polytetrafluoroethylene sheet, and the thickness of the mold is 10 μm to 20 μm.

4. The method for preparing a transparent conductive exothermic composite according to claim 3, wherein the hollowed-out portion of the hollowed-out pattern of the mold is linear with a width of 2mm to 10 mm.

5. The method for preparing the transparent conductive heating composite material according to claim 4, wherein the hollow parts of the hollow patterns of the mold are in a reciprocating folded structure.

6. The preparation method of the transparent conductive heating composite material according to claim 1, wherein the conductive heating slurry further comprises a dispersant and an organic solvent, and the mass ratio of the carbon nanotubes to the transparent conductive material, the dispersant and the organic solvent is (2.5-10): (2.5-15): (1-5): (70-96).

7. The preparation method of the transparent conductive heating composite according to claim 1, wherein the transparent conductive material is selected from at least one of poly (3, 4-ethylenedioxythiophene) -polystyrenesulfonic acid, polyacetylene, polyaniline, polypyrrole, polythioether and polyparaphenylene.

8. The method for preparing a transparent conductive heating composite material according to claim 1, wherein the first transparent substrate and the second transparent substrate are both made of glass, and before the step of bonding the second transparent substrate to the first transparent substrate on which the heating circuit is prepared, the method further comprises a step of laying an adhesive layer on a side of the first transparent substrate on which the heating circuit is provided.

9. The method for preparing a transparent conductive exothermic composite according to claim 8, wherein the thickness of the adhesive layer is 0.4mm to 2.4 mm;

10. The method for preparing a transparent conductive heating composite material according to any one of claims 1 to 9, further comprising a step of preparing a conductive member electrically connected to the heating circuit before the step of bonding the second transparent substrate to the first transparent substrate on which the heating circuit is prepared.

11. The transparent conductive heating composite material is characterized by comprising a first transparent base body, a second transparent base body and a transparent and linear heating circuit, wherein the transparent and linear heating circuit is positioned between the first transparent base body and the second transparent base body, the heating circuit is made of conductive heating slurry, the conductive heating slurry comprises carbon nano tubes, a transparent conductive material and a dispersing agent, the length-diameter ratio of the carbon nano tubes is 1000-5000, and the mass ratio of the carbon nano tubes to the transparent conductive material to the dispersing agent is (2.5-10): (2.5-15): (1-5).

12. An automobile windshield, characterized in that the windshield is prepared from the transparent conductive heating composite material prepared by the preparation method of the transparent conductive heating composite material as claimed in any one of claims 1 to 10 or the transparent conductive heating composite material as claimed in claim 11.