Preparation method of graphene silica gel sheet

Abstract

The invention discloses a preparation method of a graphene silica gel sheet, which comprises the following steps: (1) coating an insulating film with electronic paste containing graphene, and drying to obtain a graphene heating sheet; and (2) taking a piece of silica gel cloth prepared by the invention, removing the protective film on the surface of the unvulcanized silica gel layer of the silica gel cloth, then pasting a plurality of graphene heating sheets on the unvulcanized silica gel layer at intervals, then connecting conductive strips at two ends of the graphene heating sheets, and arranging a conductive silver paste layer between the connecting surfaces of the graphene heating sheets and the conductive strips. And then taking a piece of silica gel cloth, removing the protective film on the surface of the unvulcanized silica gel layer of the piece of silica gel cloth, then pasting and covering the piece of silica gel cloth, and pasting and covering the unvulcanized silica gel layer on the graphene heating sheet to obtain the composite silica gel cloth. And (3) carrying out exhaust treatment on the composite silica gel cloth, and then carrying out hot pressing treatment to obtain the graphene silica gel sheet. The silica gel sheet prepared by the invention has the characteristics of larger heating area and longer service life.

Description

Technical Field

[0001] The invention relates to the technical field of silicone heating sheets, and in particular to a method for preparing a graphene silicone sheet. Background Art

[0002] Silicone heating sheet is a flexible electric heating film element made of high temperature resistant and good insulating silicone rubber. Silicone heating sheet produced by existing technology is mainly made by corroding metal sheet and laminating the corroded metal sheet on silicone, or by laminating alloy heating wire on silicone. Due to metal fatigue and impurities, its lifespan often cannot meet the requirements. Summary of the invention

[0003] In view of the above problems, the present invention provides a method for preparing a graphene silicone sheet. The silicone sheet has the characteristics of a larger heating area and a longer life. Specifically, the present invention provides the following technical solutions.

[0004] A method for preparing a graphene silicone sheet comprises the following steps: (1) Either acrylic acid or polyurethane is coated on both sides of glass fiber cloth or chemical fiber cloth, and then dried to form a surface treatment layer to obtain a pretreated cloth.

[0005] (2) The silicone rubber and the vulcanizing agent are mixed and kneaded, and then the kneaded silicone is coated on one side of the pre-treated cloth and vulcanized to form a vulcanized silicone layer. Finally, a release protective film is attached to the surface of the vulcanized silicone layer.

[0006] (3) The mixed silicone is coated on the other side of the pretreated cloth to form an uncured silicone layer, and finally a release protective film is attached to the surface of the uncured silicone layer to obtain a silicone cloth for later use.

[0007] (4) The electronic paste containing graphene is coated on the insulating film and then dried to obtain a graphene heating sheet for later use.

[0008] (5) Take a piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and then paste a plurality of the graphene heating sheets onto the uncured silicone layer at intervals, and then connect conductive strips at both ends of the graphene heating sheet, and set a conductive silver paste layer between the connecting surfaces of the two. Then take another piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and paste it, and make the uncured silicone layer paste and cover the graphene heating sheet to obtain a composite silicone cloth.

[0009] (6) The composite silicone cloth is subjected to exhaust treatment to discharge the gas between the two pieces of the silicone cloth, and then subjected to hot pressing treatment, after which the graphene silicone sheet is obtained.

[0010] Furthermore, in step (1), the coating amount of the acrylic acid and the polyurethane is 5-50 g / m 2 The surface treatment layer formed by the acrylic acid and polyurethane helps to play a coupling role.

[0011] Furthermore, in step (1), the drying temperature is 80-150° C., and the drying time is 5-180 seconds.

[0012] Furthermore, in step (2), the amount of the vulcanizing agent added is 0.2-10 wt.%, preferably 1-6 wt.%. Optionally, 0.5-3 wt.% of color paste may also be added.

[0013] Furthermore, in steps (2) and (3), the coating thickness of the silica gel is 0.1 to 5 mm.

[0014] Furthermore, the material of the release protective film in steps (2) and (3) includes any one of PE, OPP, PET, PVC, etc.

[0015] Furthermore, in step (2), the temperature of the vulcanization treatment is 100-220°C and the time is 120-600s. Due to the good hydrophobicity of silica gel, it is difficult to print and coat the electronic paste on the surface of silica gel. However, silica gel also has excellent electrical insulation and weather resistance and is an excellent material for making heating sheets. To this end, the present invention proposes the process of steps (1) to (3) to make silica gel cloth, which lays the foundation for the subsequent successful acquisition of graphene silica gel sheets.

[0016] Furthermore, in step (4), the material of the insulating film includes: any one of PET, PI, OPP, PA, PE, etc.

[0017] Furthermore, in step (4), the electronic paste containing graphene includes: 0.1-5 parts by weight of graphene, 3-25 parts by weight of graphite, 3-30 parts by weight of carbon black, 30-50 parts by weight of carrier resin, 30-50 parts by weight of diluent, 0.5-3 parts by weight of dispersant, 0.5-5 parts by weight of leveling agent, and 0.5-5 parts by weight of defoaming agent. The above components are mixed, stirred and dispersed at high speed, and then ground to obtain the electronic paste.

[0018] Furthermore, in step (4), the coating thickness of the electronic paste is 2-15 um.

[0019] Furthermore, in step (4), the drying temperature is 100-180° C., and the drying time is 10-600 s.

[0020] Furthermore, in step (5), the spacing between adjacent graphene heating sheets ranges from 1 to 30 mm.

[0021] Furthermore, in step (5), the material of the conductive strip includes any one of copper, aluminum, etc. Preferably, the conductive strip is also provided with a connection hole to facilitate welding, riveting, etc. of the power cord in the later stage. The conductive silver paste layer can effectively overcome the current reduction effect generated between the graphene heating sheet and the conductive strip, and prevent heating and damage to the contact part.

[0022] Furthermore, in step (6), the exhaust treatment is performed by any one of the methods such as roller pressure exhaust, vacuum pressing exhaust, etc.

[0023] Furthermore, in step (6), the temperature of the hot pressing treatment is 120-200°C and the pressure is 3-50 kg / cm 2 After the hot pressing treatment, the uncured silicone layers of the two layers of the silicone cloth are completely melted together under the action of pressure and temperature, thereby sealing the graphene heating sheet therein.

[0024] Compared with the prior art, the present invention has the following beneficial effects: As mentioned above, the silicone heating plate prepared by the traditional method has metal fatigue and impurities, resulting in its lifespan often failing to meet the requirements. The graphene silicone sheet prepared by the process of the present invention overcomes the above problems well, and has the characteristics of larger heating area and longer lifespan. This is because silicone has good weather resistance and insulation properties, and graphene heating has good aging resistance, heating uniformity, and longer heating life. The glass fiber\chemical fiber grid has good firmness and can enhance the overall strength of the product. The two layers of silicone sandwich the heating plate and bond them to form a closed, waterproof, insulating, and weather-resistant whole, which is suitable for a variety of application scenarios. The surface chemical properties of the vulcanized silicone are stable, and it can be easily processed. Semi-vulcanized silicone can be easily processed in the process of bonding, closing, etc. due to its machinability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 Schematic diagram of the structure of the silica gel cloth prepared in the following examples.

[0027] Figure 2 Schematic diagram of the structure of the graphene silicone sheet prepared in the following examples. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. For example, the words "upper", "lower", "left" and "right" appearing in the present invention only indicate that they are consistent with the upper, lower, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the equipment or components referred to need to have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0030] Terminology explanation: The terms "install", "connect", "connect", "fix" and the like in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Now, the preparation method of the graphene silicone sheet of the present invention is further explained in conjunction with the drawings and specific embodiments of the specification.

[0031] Embodiment 1: A method for preparing a graphene silicone sheet comprises the following steps: (1) Apply acrylic acid on both sides of the glass fiber cloth (coating amount is 30g / m 2 ), and then dried at 100°C for 120s to form a surface treatment layer to obtain a pretreated cloth.

[0032] (2) The silicone rubber and the vulcanizing agent (benzoyl peroxide, added in an amount of 5 wt.%) were mixed and added to a rubber mixer for mixing. The mixed silicone was then coated on one side of the pretreated cloth with a coating thickness of 2 mm. The silicone was then vulcanized in a tunnel vulcanization furnace at 180°C for 350 seconds to form a vulcanized silicone layer. Finally, a layer of PET release protective film was applied to the surface of the vulcanized silicone layer.

[0033] (3) coating the mixed silicone on the other side of the pretreated cloth to form an uncured silicone layer, and finally affixing a layer of PET release protective film on the surface of the uncured silicone layer to obtain a silicone cloth (such as Figure 1 as shown).

[0034] (4) Take 4 parts by weight of graphene, 18 parts by weight of graphite, 15 parts by weight of carbon black, 40 parts by weight of carrier resin, 40 parts by weight of diluent, 2 parts by weight of dispersant, 3.6 parts by weight of leveling agent, and 0.5-5 parts by weight of defoamer. Mix the above components and disperse them by high-speed stirring, and then grind them to obtain electronic slurry. Then coat the electronic slurry on an insulating film of PET material with a coating thickness of 10um, and then dry it at 150°C for 300s to obtain a graphene heating sheet.

[0035] (5) Take a piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and then paste several graphene heating sheets on the uncured silicone layer at intervals, with the spacing between adjacent graphene heating sheets being 20 mm, and the total area of ​​the graphene heating sheets being 70% of the area of ​​the silicone cloth. Then, connect an aluminum conductive strip to each end of each graphene heating sheet, and set a conductive silver paste layer between the connecting surfaces of the two, and then open a connection hole on the conductive strip. After completion, take another piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and paste it, and make the uncured silicone layer cover the graphene heating sheet to obtain a composite silicone cloth.

[0036] (6) The composite silicone cloth is subjected to exhaust treatment by roller pressing to exhaust the gas between the two pieces of silicone cloth, and then placed in a press for hot pressing treatment (temperature 150°C, pressure 30kg / cm 2 , time is 200s), after completion, the graphene silicone sheet is obtained, such as Figure 2 shown.

[0037] Performance test: It was measured that the surface heating temperature error of the graphene silicone sheet prepared in this embodiment was 3°C, its aging life exceeded 300,000 hours, its waterproof and dustproof performance reached IP67, its voltage breakdown strength reached 3750V, its tensile strength exceeded 10N, it can withstand a 10KG steel ball drop test, and can work normally between -40 and 150°C.

[0038] Embodiment 2: A method for preparing a graphene silicone sheet comprises the following steps: (1) Apply acrylic acid on both sides of the glass fiber cloth (coating amount is 50g / m 2 ), and then dried at 150°C for 5s to form a surface treatment layer to obtain a pretreated cloth.

[0039] (2) The silicone rubber and the vulcanizing agent (benzoyl peroxide, added in an amount of 10 wt.%) are mixed and added to a rubber mixer for mixing. The mixed silicone is then coated on one side of the pretreated cloth with a coating thickness of 5 mm. The silicone is then vulcanized in a tunnel vulcanization furnace at 220°C for 120 seconds to form a vulcanized silicone layer. Finally, a layer of PE release protective film is attached to the surface of the vulcanized silicone layer.

[0040] (3) The mixed silicone is coated on the other side of the pretreated cloth to form an uncured silicone layer, and finally a layer of PE release protective film is attached to the surface of the uncured silicone layer to obtain a silicone cloth.

[0041] (4) Take 5 parts by weight of graphene, 25 parts by weight of graphite, 30 parts by weight of carbon black, 50 parts by weight of carrier resin, 50 parts by weight of diluent, 3 parts by weight of dispersant, 5 parts by weight of leveling agent, and 5 parts by weight of defoaming agent. Mix the above components and disperse them by high-speed stirring, and then grind them to obtain electronic slurry. Then coat the electronic slurry on the insulating film of PI material with a coating thickness of 15um, and then dry it at 180°C for 10s to obtain a graphene heating sheet.

[0042] (5) Take a piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and then paste several graphene heating sheets on the uncured silicone layer at intervals, with the spacing between adjacent graphene heating sheets being 1 mm, and the total area of ​​the graphene heating sheets being 85% of the area of ​​the silicone cloth. Then, connect an aluminum conductive strip to each end of each graphene heating sheet, and set a conductive silver paste layer between the connecting surfaces of the two, and then open a connection hole on the conductive strip. After completion, take another piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and paste it, and make the uncured silicone layer cover the graphene heating sheet to obtain a composite silicone cloth.

[0043] (6) The composite silicone cloth is subjected to exhaust treatment by roller pressing to exhaust the gas between the two pieces of silicone cloth, and then placed in a press for hot pressing treatment (temperature 200°C, pressure 3kg / cm 2 , time is 600s), and the graphene silicone sheet is obtained after completion.

[0044] Performance test: It was measured that the surface heating temperature error of the graphene silicone sheet prepared in this embodiment was 3°C, its aging life exceeded 300,000 hours, its waterproof and dustproof performance reached IP67, its voltage breakdown strength reached 3750V, its tensile strength exceeded 10N, it can withstand a 10KG steel ball drop test, and can work normally between -40 and 150°C.

[0045] Embodiment 3: A method for preparing a graphene silicone sheet comprises the following steps: (1) Apply acrylic acid on both sides of the chemical fiber cloth (coating amount is 5g / m 2 ), and then dried at 80°C for 180s to form a surface treatment layer to obtain a pretreated cloth.

[0046] (2) The silicone rubber and the vulcanizing agent (benzoyl peroxide, added in an amount of 0.2 wt.%) are mixed and added to a rubber mixer for mixing, and then the mixed silicone is coated on one side of the pre-treated cloth with a coating thickness of 0.1 mm. Then, the silicone is vulcanized in a tunnel vulcanization furnace at 100° C. for 600 s to form a vulcanized silicone layer. Finally, a layer of PVC release protective film is attached to the surface of the vulcanized silicone layer.

[0047] (3) The mixed silicone is coated on the other side of the pretreated cloth to form an uncured silicone layer, and finally a layer of OPP release protective film is attached to the surface of the uncured silicone layer to obtain a silicone cloth.

[0048] (4) Take 0.1 parts by weight of graphene, 3 parts by weight of graphite, 3 parts by weight of carbon black, 30 parts by weight of carrier resin, 30 parts by weight of diluent, 0.5 parts by weight of dispersant, 0.5 parts by weight of leveling agent, and 0.5 parts by weight of defoamer. Mix the above components and disperse them by high-speed stirring, and then grind them to obtain electronic slurry. Then coat the electronic slurry on the insulating film of PA material with a coating thickness of 2um, and then dry it at 100°C for 600s to obtain a graphene heating sheet.

[0049] (5) Take a piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and then paste several graphene heating sheets on the uncured silicone layer at intervals, with the spacing between adjacent graphene heating sheets being 30 mm, and the total area of ​​the graphene heating sheets being 60% of the area of ​​the silicone cloth. Then, connect an aluminum conductive strip to each end of each graphene heating sheet, and set a conductive silver paste layer between the connecting surfaces of the two, and then open a connection hole on the conductive strip. After completion, take another piece of the silicone cloth, remove the protective film on the surface of the uncured silicone layer, and paste it, and make the uncured silicone layer cover the graphene heating sheet to obtain a composite silicone cloth.

[0050] (6) The composite silicone cloth is subjected to exhaust treatment by roller pressing to exhaust the gas between the two pieces of silicone cloth, and then placed in a press for hot pressing treatment (temperature 120°C, pressure 50kg / cm 2 , time is 60s), and after completion, a graphene silicone sheet is obtained.

[0051] Performance test: It was measured that the surface heating temperature error of the graphene silicone sheet prepared in this embodiment was 3°C, its aging life exceeded 300,000 hours, its waterproof and dustproof performance reached IP67, its voltage breakdown strength reached 3750V, its tensile strength exceeded 10N, it can withstand a 10KG steel ball drop test, and can work normally between -40 and 150°C.

[0052] Finally, it should be noted that any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. Although the above describes the specific implementation of the present invention in conjunction with the drawings, it is not a limitation of the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope of the present invention.

Claims

1. A method for preparing a graphene silicone sheet, characterized in that: The steps include: (1) coating either acrylic acid or polyurethane on both sides of glass fiber cloth or chemical fiber cloth, and then drying to form a surface treatment layer to obtain a pretreated cloth; (2) mixing the silicone rubber and the vulcanizing agent and kneading them, then coating the kneaded silicone rubber on one side of the pre-treated cloth and vulcanizing it to form a vulcanized silicone layer; finally, affixing a release protective film on the surface of the vulcanized silicone layer; (3) coating the mixed silicone on the other side of the pretreated cloth to form an uncured silicone layer, and finally affixing a release protective film on the surface of the uncured silicone layer to obtain a silicone cloth for later use; (4) coating the electronic paste containing graphene on the insulating film and drying it to obtain a graphene heating sheet for later use; (5) taking a piece of the silicone cloth, removing the protective film on the surface of the uncured silicone layer, and then pasting a plurality of the graphene heating sheets onto the uncured silicone layer at intervals, and then connecting conductive strips at both ends of the graphene heating sheet, and setting a conductive silver paste layer between the connecting surfaces of the two; then taking another piece of the silicone cloth, removing the protective film on the surface of the uncured silicone layer, and pasting it, and making the uncured silicone layer pasted on the graphene heating sheet to obtain a composite silicone cloth; (6) The composite silicone cloth is subjected to exhaust treatment to discharge the gas between the two pieces of the silicone cloth, and then subjected to hot pressing treatment, after which the graphene silicone sheet is obtained.

2. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In step (1), the coating amount of the acrylic acid and polyurethane is 5-50 g / m 2 ; Optionally, in step (1), the drying temperature is 80-150° C., and the drying time is 5-180 s.

3. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In step (2), the amount of the vulcanizing agent added is 0.2-10 wt.%, preferably 1-6 wt.%; optionally, 0.5-3 wt.% of color paste is also included.

4. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: The material of the release protective film in steps (2) and (3) includes any one of PE, OPP, PET, and PVC.

5. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In steps (2) and (3), the coating thickness of the silica gel is 0.1 to 5 mm.

6. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In step (2), in step (2), the temperature of the vulcanization treatment is 100-220° C., and the time is 120-600 s; Optionally, in step (4), the material of the insulating film includes: any one of PET, PI, OPP, PA, and PE.

7. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In step (4), the electronic paste containing graphene comprises, by weight percentage: 0.1-5 parts by weight of graphene, 3-25 parts by weight of graphite, 3-30 parts by weight of carbon black, 30-50 parts by weight of carrier resin, 30-50 parts by weight of diluent, 0.5-3 parts by weight of dispersant, 0.5-5 parts by weight of leveling agent, and 0.5-5 parts by weight of defoaming agent; the above components are mixed uniformly according to the proportion to obtain the electronic paste; Optionally, in step (4), the coating thickness of the electronic paste is 2-15 um.

8. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In step (4), the drying temperature is 100-180°C and the time is 10-600s; Optionally, in step (5), the spacing between adjacent graphene heating sheets ranges from 1 to 30 mm.

9. The method for preparing a graphene silicone sheet according to claim 1, characterized in that: In step (5), the material of the conductive strip includes any one of copper, aluminum, etc.; preferably, the conductive strip is also provided with a connection hole; Optionally, in step (6), the exhaust treatment is performed by any one of roller pressing exhaust, vacuum pressing exhaust, etc.

10. The method for preparing a graphene silicone sheet according to any one of claims 1 to 9, characterized in that: In step (6), the temperature of the hot pressing treatment is 120-200°C and the pressure is 3-50 kg / cm 2 , the time is 60~600s.

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