A waterborne polyurethane conductive sponge, its preparation method and application

Abstract

The present invention provides an aqueous polyurethane conductive sponge, a preparation method thereof and an application thereof, belonging to the technical field of conductive sponges. The aqueous polyurethane conductive sponge comprises the following components in parts by weight: 26-30 parts of an aqueous polyurethane emulsion, 6-8 parts of soluble modified carbon black, 3-5 parts of mesoporous titanium oxide, 0.5-1 part of a dispersant, 2-3 parts of a foaming agent and 78-82 parts of water. The present invention ensures that the prepared conductive sponge has both excellent mechanical properties and electrical conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of conductive sponges, and particularly relates to an aqueous polyurethane conductive sponge, a preparation method thereof, and an application thereof. Background Art

[0002] A conductive sponge is a three-dimensional pore network structure material; due to its characteristics such as heat preservation, heat insulation, sound absorption, shock absorption, flame retardancy, antistatic, good air permeability, and good conductivity, it is widely used in various electronic and mobile communication devices and is very popular among the public.

[0003] In the preparation of existing conductive sponges, carbon black is generally added to an aqueous polyurethane emulsion to improve the conductivity of the conductive sponge. Although carbon black can enhance the conductivity of the conductive sponge, there are also some disadvantages.

[0004] Due to the high specific surface area and adsorption properties of carbon black, the dispersion of carbon black particles is poor and they are prone to agglomeration, resulting in uneven dispersion of carbon black in the polymer matrix. The agglomerated carbon black particles form stress concentration points in the conductive sponge, thereby reducing the overall strength of the conductive sponge, that is, affecting the mechanical properties of the conductive sponge. The uneven distribution of carbon black particles also leads to a relatively high volume resistivity of the sponge, that is, affecting the conductive performance of the conductive sponge. Summary of the Invention

[0005] To solve the problems in the background art, the present invention provides an aqueous polyurethane conductive sponge, a preparation method thereof, and an application thereof, ensuring that the prepared conductive sponge has both excellent mechanical properties and conductive properties.

[0006] To achieve the above object, in a first aspect, the present invention provides an aqueous polyurethane conductive sponge, which comprises the following components in parts by weight: 26 - 30 parts of an aqueous polyurethane emulsion, 6 - 8 parts of soluble modified carbon black, 3 - 5 parts of mesoporous titanium oxide, 0.5 - 1 part of a dispersant, 2 - 3 parts of a foaming agent, and 78 - 82 parts of water.

[0007] Further, the preparation method of the mesoporous titanium oxide is as follows:

[0008] A1. Slowly add tetrabutyl titanate and acetylacetone simultaneously to an ethanol aqueous solution containing cetyltrimethylammonium bromide, and stir at room temperature for 1 h to obtain a first solution;

[0009] A2. Add concentrated hydrochloric acid to the ethanol aqueous solution, mix evenly to obtain a second solution;

[0010] A3. Add the second solution obtained in A2 to the first solution obtained in A1 at a dropping rate of 1 - 2 drops / s, and continue stirring for 4 h to obtain a sol solution with a pH value of 3 - 4. Among them, the molar ratio of tetrabutyl titanate, acetylacetone, cetyltrimethylammonium bromide, ethanol, and water is 1:0.3:0.05:(14 - 18):5.

[0011] A4. After the sol solution obtained in A3 gels for 12 h, it is successively subjected to aging, drying, and calcination to obtain mesoporous titanium oxide.

[0012] Further, in A4, the specific operation of aging is as follows: First, age at a temperature of 20 - 25 °C for 1 d, and then age at a temperature of 65 - 75 °C for 2 - 3 d.

[0013] Further, in A4, the specific operation of drying is as follows: Heat up to 110 - 120 °C at a rate of 2 °C / min and keep warm for 10 - 12 h.

[0014] Further, in A4, the specific operation of calcination is as follows: Heat up to 340 - 350 °C at a rate of 1 °C / min and keep warm for 4 - 5 h.

[0015] Further, the preparation method of the soluble modified carbon black is as follows:

[0016] B1. Take 5 g of carbon black and 150 mL of nitric acid with a mass fraction of 67% and place them in a three-necked flask. React at 100 °C for 72 - 80 h under stirring conditions to obtain a first reactant.

[0017] B2. Centrifuge the first reactant to obtain a soluble substance and a first insoluble substance. The soluble substance is concentrated by a rotary evaporator, and after concentration, continue to wash with water until the pH value of the eluate is 7 to obtain a first solution.

[0018] B3. Wash the first insoluble substance with water, then centrifuge the washing solution to obtain a second solution and a second insoluble substance. Continue to wash the second insoluble substance with water, and then centrifuge the washing solution to obtain a third solution and a third insoluble substance. After combining the third solution, the second solution, and the first solution, concentrate them with a rotary evaporator to obtain a concentrated solution, and dry it at 120 - 130 °C for 8 - 10 h to obtain the soluble modified carbon black.

[0019] Further, the dispersant includes polysiloxane ethane dispersant and / or polyether-type silicone dispersant.

[0020] Further, the foaming agent includes coconut oil fatty acid diethanolamide and / or sodium dodecyl polyoxyethylene ether sulfate.

[0021] In a second aspect, the present invention provides a method for preparing the above-mentioned aqueous polyurethane conductive sponge, which includes the following steps: first, dilute the aqueous polyurethane emulsion with water; then add a dispersant, soluble modified carbon black and mesoporous titanium oxide, and stir for 10-15 minutes; then add a foaming agent and stir for 15-20 minutes; then place it in a blast drying oven at 60-80 °C for curing and forming; finally, place it under room temperature ventilation conditions for 20-24 hours to obtain the aqueous polyurethane conductive sponge.

[0022] In a third aspect, the present invention provides an application of the above-mentioned aqueous polyurethane conductive sponge, which is used for electronic products, medical devices and packaging materials.

[0023] This application has the following beneficial effects:

[0024] 1. Mesoporous titanium oxide has a unique pore structure and a large specific surface area, and soluble modified carbon black provides more attachment points and reaction sites. When soluble modified carbon black combines with mesoporous titanium oxide, soluble modified carbon black is evenly distributed on the surface and pores of mesoporous titanium oxide, forming a more complex network structure. This structure not only increases the specific surface area of the conductive sponge, but also improves the mechanical properties of the conductive sponge. When soluble modified carbon black is filled into the pores of mesoporous titanium oxide, the composite structure formed by the two has a more optimized pore distribution trend and mechanical properties, which helps to improve the conductivity and mechanical properties of the conductive sponge.

[0025] 2. Oxygen-containing functional groups are introduced on the surface of soluble modified carbon black. These functional groups have high chemical activity and react with the active sites on the surface of mesoporous titanium oxide to form stable chemical bonds, enhancing the binding force between soluble modified carbon black and mesoporous titanium oxide and improving the mechanical properties of the conductive sponge; when mesoporous titanium oxide and soluble modified carbon black combine, the pore structure of mesoporous titanium oxide helps the dispersion and uniform distribution of soluble modified carbon black, thereby optimizing the formation of the conductive network to form a more optimized conductive network in the conductive sponge. This conductive network not only improves the conductivity of the conductive sponge, but also promotes the transmission of electrons in the conductive network; in the conductive network, the electron transmission speed between soluble modified carbon black and mesoporous titanium oxide is significantly increased because the oxygen-containing functional groups on the surface of soluble modified carbon black act as "springboards" for electrons, promoting the hopping transmission of electrons between mesoporous titanium oxides. This electron transmission mechanism can further improve the conductivity of the conductive sponge. Description of the Drawings

[0026] Figure 1 Trend chart of comparison of test data on the mechanical properties (tensile strength) of the conductive sponges prepared in Examples 1-4 and Comparative Examples 1-5 of the present invention;

[0027] Figure 2、Comparison trend chart of the electrical conductivity (volume resistivity) test data of the conductive sponges prepared in Examples 1-4 and Comparative Examples 1-5 of the present invention. Detailed implementation manners

[0028] The following further elaborates on this application in conjunction with examples.

[0029] The raw materials of the examples and comparative examples of this application are all ordinary commercially available ones unless otherwise specified.

[0030] Example 1: (1) The preparation method of mesoporous titanium oxide is as follows:

[0031] A1. Slowly add 2 mol of tetrabutyl titanate and 0.6 mol of acetylacetone into an ethanol aqueous solution containing 0.1 mol of cetyltrimethylammonium bromide. This ethanol aqueous solution includes 24 mol of ethanol and 8 mol of water. Stir at a constant speed of 180 r / min at room temperature for 1 h to obtain a first solution.

[0032] A2. Add concentrated hydrochloric acid to the ethanol aqueous solution. This ethanol aqueous solution includes 6 mol of ethanol and 2 mol of water. Stir at a constant speed of 180 r / min for 5 min to mix evenly and obtain a second solution.

[0033] A3. Add the second solution obtained in A2 to the first solution obtained in A1 at a dropping rate of 1 drop / s, and continue to stir at a speed of 180 r / min for 4 h to obtain a sol solution with a pH value of 3.5.

[0034] A4. After the sol solution obtained in A3 is left standing for 12 h and gelled, it is successively subjected to aging, drying, and calcination. The specific operation of aging is as follows: first age at 22 °C for 1 d, and then age at 70 °C for 2 d; the specific operation of drying is as follows: heat up to 115 °C at a rate of 2 °C / min and keep warm for 12 h; the specific operation of calcination is as follows: continue to heat up to 345 °C at a rate of 1 °C / min and keep warm for 5 h; thus, mesoporous titanium oxide is obtained.

[0035] Among them, tetrabutyl titanate (99%) is purchased from Shandong Linguan Fine Chemical Co., Ltd. Acetylacetone (industrial grade 99.5%) is purchased from Shandong Xinheng Chemical Co., Ltd. Cetyltrimethylammonium bromide (99%) is purchased from Anhui Banghao Chemical Co., Ltd.

[0036] (2) The preparation method of soluble modified carbon black is as follows:

[0037] B1. Take 5 g of carbon black and 150 mL of nitric acid with a mass fraction of 67% and place them in a three-necked flask. React at 100 °C for 75 h under the condition of stirring at a speed of 150 r / min to obtain a first reactant.

[0038] B2. Centrifuge the first reactant to obtain a soluble substance and a first insoluble substance. Concentrate the soluble substance using a rotary evaporator and then continue to wash it with water until the pH value of the eluate is 7 to obtain a first solution.

[0039] B3. Wash the first insoluble substance with water, and then centrifuge the washing solution to obtain a second solution and a second insoluble substance. Continue to wash the second insoluble substance with water, and then centrifuge the washing solution to obtain a third solution and a third insoluble substance. Combine the third solution, the second solution, and the first solution, concentrate them using a rotary evaporator, and dry the resulting concentrate at 125 °C for 9 h to obtain soluble modified carbon black.

[0040] Among them, the carbon black (VXC-72) was purchased from Tianjin Tianyi Century Chemical Products Technology Development Co., Ltd.

[0041] (3) A preparation method of an aqueous polyurethane conductive sponge, comprising the following steps: By weight, first dilute 28 parts of an aqueous polyurethane emulsion with 80 parts of water. The specific operation is to add 28 parts of the aqueous polyurethane emulsion to 80 parts of water and stir evenly at 220 r / min for 20 min. Then add 0.8 part of a dispersant, 7 parts of soluble modified carbon black, and 4 parts of mesoporous titanium oxide, and continue to stir evenly at 220 r / min for 13 min. Then add 2.5 parts of a foaming agent and continue to stir evenly at 220 r / min for 17 min. Then place it in a blast drying oven at 70 °C for 24 h to cure and form. Finally, place it under room temperature ventilation conditions for 22 h to obtain the aqueous polyurethane conductive sponge.

[0042] Among them, the aqueous polyurethane emulsion (BASF, ECO 3702) was purchased from Foshan Nanhai Hengxiehui Chemical Co., Ltd. The dispersant is a BYK polyether silicone copolymer dispersant, purchased from Guangzhou Suxinying Trading Co., Ltd. The foaming agent is coconut oil fatty acid diethanolamide, purchased from Guangzhou Zhongye Chemical Co., Ltd.

[0043] Example 2: The difference between this example and Example 1 lies in: (3) A preparation method of an aqueous polyurethane conductive sponge, comprising the following steps: First dilute 26 parts of an aqueous polyurethane emulsion with 78 parts of water; then add 0.5 part of a dispersant, 6 parts of soluble modified carbon black, and 3 parts of mesoporous titanium oxide, and stir for 10 min; then add 2 parts of a foaming agent and stir for 15 min; then place it in a blast drying oven at 60 °C to cure and form; finally, place it under room temperature ventilation conditions for 20 h to obtain the aqueous polyurethane conductive sponge.

[0044] Example 3: The difference between this example and Example 1 lies in: (3) A preparation method of a waterborne polyurethane conductive sponge, which includes the following steps: First, dilute 30 parts of waterborne polyurethane emulsion with 82 parts of water; then add 1 part of dispersant, 8 parts of soluble modified carbon black, and 5 parts of mesoporous titanium oxide, and stir for 15 min; then add 3 parts of foaming agent and stir for 20 min; then place it in a blast drying oven at 80 °C for curing and forming; finally, place it for 24 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge.

[0045] Example 4: The difference between this example and Example 1 lies in: (3) A preparation method of a waterborne polyurethane conductive sponge, which includes the following steps: First, dilute 30 parts of waterborne polyurethane emulsion with 78 parts of water; then add 0.6 part of dispersant, 7 parts of soluble modified carbon black, and 4 parts of mesoporous titanium oxide, and stir for 12 min; then add 2.5 parts of foaming agent and stir for 15 min; then place it in a blast drying oven at 75 °C for curing and forming; finally, place it for 22 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge.

[0046] Comparative Example 1: The difference between this comparative example and Example 1 lies in: deleting mesoporous titanium oxide and replacing soluble modified carbon black with carbon black.

[0047] Specifically, a preparation method of a waterborne polyurethane conductive sponge includes the following steps: By weight, first dilute 28 parts of waterborne polyurethane emulsion with 80 parts of water; then add 0.8 part of dispersant and 7 parts of carbon black, and stir at a constant speed of 220 r / min for 13 min; then add 2.5 parts of foaming agent and continue to stir at a constant speed of 220 r / min for 17 min; then place it in a blast drying oven at 70 °C for 24 h for curing and forming; finally, place it for 22 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge.

[0048] Comparative Example 2: The difference between this comparative example and Example 1 lies in: replacing mesoporous titanium oxide with titanium oxide and replacing soluble modified carbon black with carbon black.

[0049] Specifically, a preparation method of a waterborne polyurethane conductive sponge includes the following steps: By weight, first dilute 28 parts of waterborne polyurethane emulsion with 80 parts of water; then add 0.8 part of dispersant, 7 parts of carbon black, and 4 parts of titanium oxide, and continue to stir at a constant speed of 220 r / min for 13 min; then add 2.5 parts of foaming agent and continue to stir at a constant speed of 220 r / min for 17 min; then place it in a blast drying oven at 70 °C for 24 h for curing and forming; finally, place it for 22 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge. Among them, the titanium oxide is purchased from Wuxi Henderson Chemical Products Co., Ltd.

[0050] Comparative Example 3: The difference between this comparative example and Example 1 lies in: replacing soluble modified carbon black with carbon black.

[0051] Specifically, a preparation method of a waterborne polyurethane conductive sponge comprises the following steps: By weight, first dilute 28 parts of waterborne polyurethane emulsion with 80 parts of water; then add 0.8 part of dispersant, 7 parts of carbon black and 4 parts of mesoporous titanium oxide, and continue to stir at a constant speed of 220 r / min for 13 min; then add 2.5 parts of foaming agent, and continue to stir at a constant speed of 220 r / min for 17 min; then place it in a blast drying oven at 70 °C for 24 h to cure and form; finally, place it for 22 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge.

[0052] Comparative Example 4: The difference between this comparative example and Example 1 is that: mesoporous titanium oxide is replaced by titanium oxide.

[0053] Specifically, a preparation method of a waterborne polyurethane conductive sponge comprises the following steps: By weight, first dilute 28 parts of waterborne polyurethane emulsion with 80 parts of water; then add 0.8 part of dispersant, 7 parts of soluble modified carbon black and 4 parts of titanium oxide, and continue to stir at a constant speed of 220 r / min for 13 min; then add 2.5 parts of foaming agent, and continue to stir at a constant speed of 220 r / min for 17 min; then place it in a blast drying oven at 70 °C for 24 h to cure and form; finally, place it for 22 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge.

[0054] Comparative Example 5: The difference between this comparative example and Example 1 is that: soluble modified carbon black is replaced by insoluble modified carbon black.

[0055] Specifically, a preparation method of a waterborne polyurethane conductive sponge comprises the following steps: By weight, first dilute 28 parts of waterborne polyurethane emulsion with 80 parts of water; then add 0.8 part of dispersant, 7 parts of insoluble modified carbon black and 4 parts of mesoporous titanium oxide, and continue to stir at a constant speed of 220 r / min for 13 min; then add 2.5 parts of foaming agent, and continue to stir at a constant speed of 220 r / min for 17 min; then place it in a blast drying oven at 70 °C for 24 h to cure and form; finally, place it for 22 h under room temperature ventilation conditions to obtain the waterborne polyurethane conductive sponge.

[0056] The preparation method of the insoluble modified carbon black is as follows:

[0057] B1. Take 5 g of carbon black and 150 mL of nitric acid with a mass fraction of 67% and place them in a three-necked flask. Under the condition of stirring at a speed of 150 r / min, react at 100 °C for 75 h to obtain a first reactant.

[0058] B2. Centrifuge the first reactant to obtain a soluble substance and an insoluble substance. Wash the insoluble substance with water until the pH value of the washing liquid is 7, and then dry the insoluble substance washed to neutral at 125 °C for 9 h to obtain the insoluble modified carbon black.

[0059] Test Example: The test subjects were the conductive sponges prepared in Examples 1 - 4 and Comparative Examples 1 - 5. The test data of the mechanical properties (tensile strength) and electrical conductivity (volume resistivity) of each test subject (conductive sponge) are shown in Table 1.

[0060] Table 1. Test Data of Test Example

[0061] Tensile strength / MPa <![CDATA[Volume resistivity / *10 4 Ω·cm]]> Example 1 0.078 2.35 Example 2 0.075 2.36 Example 3 0.081 2.34 Example 4 0.077 2.34 Comparative Example 1 0.060 3.87 Comparative Example 2 0.061 3.86 Comparative Example 3 0.067 3.45 Comparative Example 4 0.058 4.12 Comparative Example 5 0.072 2.75

[0062] Result Analysis: Analyzing Examples 1 - 4 and combining with the data in Table 1 and Figure 1 - Figure 2 It can be seen that the conductive sponge prepared by the present invention has both excellent mechanical properties and electrical conductivity. The tensile strength reaches above 0.075 MPa, and the volume resistivity is as low as 2.36*10 4 Ω·cm or less.

[0063] Analyzing Example 1 and Comparative Examples 1 - 5 and combining with the data in Table 1 and Figure 1 - Figure 2 , by comparing Comparative Example 1 and Comparative Example 2, it can be known that compared with Comparative Example 1, titanium oxide was added to the raw material components of Comparative Example 2. As a result, the tensile strength test data of the conductive sponge prepared in Comparative Example 2 was 0.062 MPa, slightly greater than 0.060 MPa of Comparative Example 1; at the same time, the volume resistivity test data of the conductive sponge prepared in Comparative Example 2 was 3.86*10 4 Ω·cm, slightly lower than 3.87*10 4 Ω·cm of Comparative Example 1. It shows that the addition of titanium oxide has little effect on the tensile strength and volume resistivity of the prepared conductive sponge.

[0064] By comparing Comparative Example 1 and Comparative Example 3, it can be known that compared with Comparative Example 1, mesoporous titanium oxide was added to the raw material components of Comparative Example 3. As a result, the tensile strength test data of the conductive sponge prepared in Comparative Example 3 was 0.067 MPa, significantly greater than 0.060 MPa of Comparative Example 1; at the same time, the volume resistivity test data of the conductive sponge prepared in Comparative Example 3 was 3.45*10 4 Ω·cm, significantly less than 3.87*10 4 Ω·cm of Comparative Example 1. It shows that the addition of mesoporous titanium oxide can improve the tensile strength of the prepared conductive sponge and can reduce the volume resistivity of the prepared conductive sponge; that is, it can improve the mechanical properties and electrical conductivity of the prepared conductive sponge.

[0065] By comparing Comparative Example 2 and Comparative Example 4, it can be known that compared with Comparative Example 2 (the raw material components contain carbon black and titanium oxide), in Comparative Example 4, the carbon black in the raw material components was replaced with soluble modified carbon black. As a result, the tensile strength test data of the conductive sponge prepared in Comparative Example 4 was 0.058 MPa, less than 0.062 MPa of Comparative Example 2; at the same time, the volume resistivity test data of the conductive sponge prepared in Comparative Example 4 was 4.12*104 Ω·cm, greater than 3.86×10 of Comparative Example 2 4 Ω·cm. It shows that when there is titanium oxide in the raw material components, replacing the carbon black in the raw material components with soluble modified carbon black will instead lead to a decrease in the tensile strength of the prepared conductive sponge and an increase in the volume resistivity; that is, it will lead to a decline in the mechanical properties and conductive properties of the prepared conductive sponge.

[0066] This is because compared with carbon black, due to the increased solubility of soluble modified carbon black, its solubility is too high, resulting in its excessive dispersion or aggregation in the matrix, thus affecting its uniform distribution in the matrix; while the adsorption capacity of titanium oxide is limited and lacks selectivity, and it cannot provide a stable, reliable and uniform adsorption effect to soluble modified carbon black, which will lead to insufficient bonding strength and the inability to form a stable, reliable and uniformly textured conductive network, ultimately resulting in a decline in the mechanical properties and conductive properties of the prepared conductive sponge.

[0067] By comparing Comparative Example 3 and Comparative Example 5, it can be seen that compared with Comparative Example 3 (the raw material components contain carbon black and mesoporous titanium oxide), in Comparative Example 5, the carbon black in the raw material components is replaced with insoluble modified carbon black. As a result, the tensile strength test data of the conductive sponge prepared in Comparative Example 5 is 0.072 MPa, greater than 0.067 MPa of Comparative Example 3; at the same time, the volume resistivity test data of the conductive sponge prepared in Comparative Example 5 is 2.75×10 4 Ω·cm, less than 3.45×10 of Comparative Example 3 4 Ω·cm. It shows that when there is mesoporous titanium oxide in the raw material components, replacing the carbon black in the raw material components with insoluble modified carbon black can improve the tensile strength of the prepared conductive sponge and can reduce the volume resistivity of the prepared conductive sponge; that is, it can enhance the mechanical properties and conductive properties of the prepared conductive sponge.

[0068] By comparing Comparative Example 3 and Example 1, it can be seen that compared with Comparative Example 3 (the raw material components contain carbon black and mesoporous titanium oxide), in Example 1, the carbon black in the raw material components is replaced with soluble modified carbon black. As a result, the tensile strength test data of the conductive sponge prepared in Example 1 is 0.078 MPa, significantly greater than 0.067 MPa of Comparative Example 3; at the same time, the volume resistivity test data of the conductive sponge prepared in Example 1 is 2.35×10 4 Ω·cm, significantly less than 3.45×10 of Comparative Example 3 4 Ω·cm. It shows that when there is mesoporous titanium oxide in the raw material components, replacing the carbon black in the raw material components with soluble modified carbon black can also improve the tensile strength of the prepared conductive sponge and can also reduce the volume resistivity of the prepared conductive sponge; that is, it can enhance the mechanical properties and conductive properties of the prepared conductive sponge.

[0069] In summary, when titanium oxide is used as the raw material component, replacing carbon black with soluble modified carbon black will instead lead to a decrease in the mechanical and electrical conductivity of the prepared conductive sponge. When mesoporous titanium oxide is used as the raw material component, replacing carbon black with insoluble modified carbon black can improve the mechanical and electrical conductivity of the prepared conductive sponge; replacing carbon black with soluble modified carbon black can further improve the mechanical and electrical conductivity of the prepared conductive sponge. This indicates that there is a synergistic effect between mesoporous titanium oxide and soluble modified carbon black, which can synergistically improve the mechanical and electrical conductivity of the prepared conductive sponge.

[0070] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0071] Furthermore, any combination can be made among the various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A water-based polyurethane conductive sponge, characterized in that: The composition comprises the following components by weight: 26-30 parts of aqueous polyurethane emulsion, 6-8 parts of soluble modified carbon black, 3-5 parts of mesoporous titanium oxide, 0.5-1 parts of dispersant, 2-3 parts of foaming agent and 78-82 parts of water; The preparation method of the soluble modified carbon black is as follows: B1. Take 5 g of carbon black and 150 mL of 67% nitric acid in a three-necked flask, react at 100° C. for 72-80 h under stirring to obtain a first reactant; B2, centrifuging the first reactant to obtain a soluble substance and a first insoluble substance, concentrating the soluble substance using a rotary evaporator, and continuing to wash with water until the pH value of the eluent reaches 7, thereby obtaining a first solution; B3. Wash the first insoluble matter with water, then centrifuge the washing liquid into a second solution and a second insoluble matter, continue to wash the second insoluble matter with water, then centrifuge the washing liquid into a third solution and a third insoluble matter, combine the third solution, the second solution and the first solution, concentrate them with a rotary evaporator to obtain a concentrated solution, and dry them at 120-130°C for 8-10h to obtain soluble modified carbon black.

2. The aqueous polyurethane conductive sponge according to claim 1, characterized in that: The preparation method of the mesoporous titanium oxide is as follows: A1. Slowly add butyl titanate and acetylacetone to an ethanol aqueous solution containing hexadecyltrimethylammonium bromide at the same time, and stir at room temperature for 1 hour to obtain a first solution; A2, adding concentrated hydrochloric acid to the ethanol aqueous solution, mixing evenly, to obtain a second solution; A3, adding the second solution obtained in A2 to the first solution obtained in A1 at a dropping speed of 1-2 drops / s, and continuing stirring for 4 hours to obtain a sol solution with a pH value of 3-4; wherein the molar ratio of butyl titanate, acetylacetone, hexadecyltrimethylammonium bromide, ethanol and water is 1:0.3:0.05:(14-18):5; A4. After the sol solution obtained in A3 is gelled for 12 hours, it is aged, dried and calcined in sequence to obtain mesoporous titanium oxide.

3. The aqueous polyurethane conductive sponge according to claim 2, characterized in that: In A4, the specific operation of aging is: first aging at 20-25°C for 1 day, and then aging at 65-75°C for 2-3 days.

4. The aqueous polyurethane conductive sponge according to claim 2, characterized in that: In A4, the specific drying operation is: heating to 110-120°C at a rate of 2°C / min and keeping the temperature for 10-12h.

5. The aqueous polyurethane conductive sponge according to claim 2, characterized in that: In A4, the specific operation of roasting is: heating to 340-350°C at a rate of 1°C / min and keeping the temperature for 4-5h.

6. The waterborne polyurethane conductive sponge according to claim 1, characterized in that: The dispersant includes a polysiloxane dispersant and / or a polyether type silicone dispersant.

7. The waterborne polyurethane conductive sponge according to claim 1, characterized in that: The foaming agent includes coconut oil fatty acid diethanolamide and / or sodium lauryl polyoxyethylene ether sulfate.

8. A method for preparing the waterborne polyurethane conductive sponge according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: firstly diluting the water-based polyurethane emulsion with water; then adding a dispersant, soluble modified carbon black and mesoporous titanium oxide, and stirring for 10-15 minutes; then adding a foaming agent, and stirring for 15-20 minutes; then placing in a 60-80°C forced air oven for curing and forming; and finally placing at room temperature under ventilation conditions for 20-24 hours to obtain a water-based polyurethane conductive sponge.

9. An application of the waterborne polyurethane conductive sponge according to any one of claims 1 to 7, characterized in that: Used in electronic products, medical devices and packaging materials.

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