Piezoelectric type abnormal sound prevention synthetic leather and preparation method thereof

Abstract

The invention belongs to the technical field of synthetic leather, and relates to piezoelectric type abnormal sound prevention synthetic leather and a preparation method thereof. The piezoelectric type abnormal sound prevention synthetic leather is of a structure with at least four layers and comprises a base cloth layer, a bonding layer, a bottom surface layer and a top surface layer, the top surface layer contains functional powder, and the content of the functional powder in the top surface layer does not exceed 25wt%; the functional powder comprises piezoelectric powder, and the content of the piezoelectric powder in the top surface layer is not lower than 10 wt%; the piezoelectric powder is zinc oxide powder doped with silver ions, and the doping amount of the silver ions is 0.01-0.15. The preparation method comprises the following steps: impregnating the non-woven fabric in impregnation slurry, solidifying, washing to obtain the base fabric layer, and sequentially forming the bonding layer, the bottom surface layer and the top surface layer on the surface of the base fabric layer. According to the invention, the problem of insufficient inhibition of medium-high frequency abnormal sound in the prior art is solved, and the abnormal sound prevention effect of the synthetic leather is effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of synthetic leather, and relates to piezoelectric anti-abnormal sound synthetic leather and a preparation method thereof. BACKGROUND

[0002] Microfiber synthetic leather is widely used in our daily life. However, most of the microfiber synthetic leather on the market has an abnormal sound problem to varying degrees. The extrusion and friction between materials produce a squeaking sound, which brings obvious discomfort to people. With the improvement of living quality, people have higher requirements for the mute performance of synthetic leather in daily use.

[0003] To solve the abnormal sound problem, relevant technical personnel attempts to modify the surface of the material by adding damping powder, so that the material has certain viscoelasticity. When the vibration frequency and the characteristic time of the internal chain segment movement are in the same order of magnitude, the modified material can convert mechanical vibration energy into heat energy, thereby improving the abnormal sound condition to a certain extent. The principle of action is mainly to absorb vibration energy through internal friction or viscoelastic effect of the damping powder. Although this scheme has a certain inhibitory effect on the abnormal sound generated by vibration, it is still unsatisfactory for some high-demand use scenarios.

[0004] In order to expand the application scenario range of the material and improve the anti-abnormal sound effect, the anti-abnormal sound material with piezoelectric effect becomes a new direction worth exploring.

[0005] In other fields, relevant technical personnel has carried out certain research on piezoelectric powder. For example, the patent application with publication number CN114220912A discloses a 3D printable / thermoforming piezoelectric composite material and a preparation method thereof. The method first mixes surface-modified barium titanate with a polymer, and then processes and forms and polarizes the electrodes to finally obtain a composite material with piezoelectric properties.

[0006] However, at present, there is no related report on using piezoelectric powder to solve the abnormal sound problem of synthetic leather. Common piezoelectric powders include zinc oxide and barium titanate. When they are applied to the preparation of synthetic leather, there is a problem that mechanical energy is difficult to convert into electrical energy, which constitutes a technical obstacle to solving the abnormal sound problem. SUMMARY

[0007] The purpose of the present application is to solve the problems existing in the prior art and provide piezoelectric anti-abnormal sound synthetic leather and a preparation method thereof.

[0008] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0009] The piezoelectric anti-abnormal sound synthetic leather has a multi-layer (at least three layers) structure, including a base cloth layer, a bonding layer and a surface layer; the surface layer contains functional powder, and the content of the functional powder in the surface layer is not more than 25wt%; the functional powder includes piezoelectric powder, and the content of the piezoelectric powder in the surface layer is not less than 10wt%; the piezoelectric powder is silver ion doped zinc oxide powder, and the doping amount of silver ions is 0.01-0.15 (the doping amount of silver ions = the mass percentage of silver element / the mass percentage of zinc element, which can be measured by an X-ray fluorescence spectrometer).

[0010] The present application introduces a certain amount of functional powder into the surface layer of the synthetic leather, and controls the functional powder to include piezoelectric powder, so that the abnormal sound can be improved by consuming the mechanical energy of vibration. Under low-frequency friction vibration, the functional powder and the polyurethane resin produce microscopic slip and friction, which can convert part of the mechanical energy of vibration into internal heat energy; under medium and high-frequency friction vibration, the piezoelectric powder converts the mechanical energy of vibration into electrical energy. Therefore, the present application can improve the abnormal sound of low, medium and high-frequency friction vibration.

[0011] To ensure that the piezoelectric powder can effectively convert the mechanical energy of vibration into electrical energy, on the one hand, the type of piezoelectric powder needs to be controlled, and on the other hand, the amount of piezoelectric powder needs to be controlled. Zinc oxide powder is a known piezoelectric powder, which is usually used in the field of sensors, but when it is applied to synthetic leather, it is difficult to effectively convert the mechanical energy of vibration into electrical energy. The possible reason is that the oxygen vacancy defects in the zinc oxide crystal lattice can destroy the continuity of the piezoelectricity, and the doping of silver ions can fill the oxygen vacancies and promote the rapid transmission of piezoelectric charge. The inventors have found through many attempts that the silver ion doped zinc oxide powder has an ideal conversion effect, which is specifically that under the same conditions, the conversion charge amount of the silver ion doped zinc oxide powder is significantly higher than that of the conventional zinc oxide powder, because the silver ion doped zinc oxide powder improves the interface strain potential. The present application controls the content of the piezoelectric powder in the surface layer to be not less than 10wt%, so as to effectively convert the mechanical energy of vibration into electrical energy. The present application controls the doping amount of silver ions in the silver ion doped zinc oxide powder to be 0.01-0.15. If the doping amount of silver ions is too small, the electrical energy conversion effect of the piezoelectric powder is not good, and if the doping amount of silver ions is too large, it will increase the migration resistance of zinc oxide carriers and also destroy the electrical energy conversion effect of the piezoelectric powder, thereby causing the abnormal sound problem cannot be solved.

[0012] The present application controls the content of the functional powder in the surface layer to be not more than 25wt%. If the content of the functional powder is too high, it is easy to agglomerate, which will cause interface defects, poor abnormal sound improvement effect, and easy to cause the surface layer to have poor appearance. Such appearance defects will cause the entire synthetic leather to be scrapped.

[0013] As a preferred technical solution:

[0014] The piezoelectric anti-abnormal-sound synthetic leather has a silver ion doped zinc oxide powder with a mesh number of 200-1000 meshes and a piezoelectric strain constant of greater than or equal to 50 pC / N.

[0015] The piezoelectric anti-abnormal-sound synthetic leather has a silver ion doped zinc oxide powder with a mesh number of 200-1000 meshes and a piezoelectric strain constant of greater than or equal to 50 pC / N.

[0016] The piezoelectric powder converts the vibration mechanical energy into electric energy, and if the electric energy cannot be transferred in time, the synthetic leather will have a certain degree of electric shock feeling, therefore, a certain amount of conductive powder is added in each layer, and the content of the conductive powder in each layer is controlled to build an electric energy release path and transfer the electric energy in time.

[0017] If the difference between the contents of the conductive powder in the adjacent two layers is too small (less than 1 wt%), the current tends to concentrate in the surface layer with the smallest resistance, and the local current density is prone to be too high, which cannot conduct the electric energy of the surface layer to the entire synthetic leather, and is not conducive to weakening static electricity; if the difference between the contents of the conductive powder in the adjacent two layers is too large (greater than 2 wt%), the interface resistance between the adjacent two layers is too large, and otherwise the electric energy of the surface layer cannot be quickly conducted to the entire synthetic leather.

[0018] The content of the conductive powder in the surface layer and the base cloth layer is not less than 5 wt%, so that the electric energy can be quickly conducted out.

[0019] The piezoelectric anti-abnormal-sound synthetic leather has a silver ion doped zinc oxide powder with a mesh number of 200-1000 meshes and a piezoelectric strain constant of greater than or equal to 50 pC / N. 3 Ω·cm; the conductive powder is graphene.

[0020] The piezoelectric anti-abnormal-sound synthetic leather has a silver ion doped zinc oxide powder with a mesh number of 200-1000 meshes and a piezoelectric strain constant of greater than or equal to 50 pC / N.

[0021] The piezoelectric anti-rustling synthetic leather has a conversion charge of 474-3622 pC and a surface voltage of 15-30 V, and has a coefficient of stick-slip of 1-5 and a softness of 2.6-4.5 mm.

[0022] The application further provides a method for preparing the piezoelectric anti-rustling synthetic leather.

[0023] (a) dipping the non-woven fabric into an impregnation slurry to obtain a base layer through solidification and water washing, wherein the viscosity of the impregnation slurry is 30,000-50,000 CPS, and the impregnation slurry mainly comprises polyurethane resin and a solvent;

[0024] (b) coating a bonding layer slurry on the surface of the base layer, and forming a bonding layer on the base layer after solidification of the bonding layer slurry, wherein the viscosity of the bonding layer slurry is 70,000-90,000 CPS, and the bonding layer slurry mainly comprises a bonding layer resin and a solvent, and the bonding layer resin is used to bond the base layer and the surface layer, and the application does not limit the type of the bonding layer resin, and the type of the bonding layer resin can be adjusted according to actual needs without affecting the solving effect of the application on the technical problem;

[0025] (c) coating a surface layer slurry on the bonding layer, and forming a surface layer on the bonding layer after solidification of the surface layer slurry, so as to obtain a piezoelectric anti-rustling synthetic leather with a base layer-bonding layer-surface layer structure, wherein the viscosity of the surface layer slurry is 1,000-3,000 CPS, and the surface layer slurry mainly comprises polyurethane resin, functional powder and a solvent.

[0026] As a preferred technical solution,

[0027] The method as described above, wherein the conductive powder is added to the impregnation slurry, the bonding layer slurry and the surface layer slurry.

[0028] The method as described above, wherein an electric field is applied when at least one of the bonding layer slurry and the surface layer slurry is coated, the electric field has a strength of 1-5 KV / mm and a direction parallel to the coating surface, and the action time is 10-60 s, and the application of the electric field can adjust the direction of the conductive powder, so as to increase the contact probability between the layers and reduce the interlayer contact resistance.

[0029] The application further provides a piezoelectric powder for modifying the microfiber leather slurry, and the piezoelectric powder is silver ion doped zinc oxide powder, and the doping amount of the silver ion is 0.01-0.15.

[0030] As a preferred technical solution,

[0031] The piezoelectric powder used for modifying microfiber leather slurry, as described above, has a silver ion-doped zinc oxide powder with a mesh size of 200-1000 mesh and a piezoelectric strain constant ≥50pC / N.

[0032] The preparation process of the silver ion-doped zinc oxide powder for modifying microfiber leather slurry, as described above, is as follows: zinc oxide powder of the target mesh size is immersed in a solution containing silver ions, and then the immersed powder is heat-treated to obtain silver ion-doped zinc oxide powder; wherein, in the solution containing silver ions, the solute is silver salt, the solvent is water, the concentration is 0.1-5wt%, the immersion temperature is 40-60℃, the immersion time is 1-4h, the heat treatment temperature is 300-500℃, and the heat treatment time is 1-3h.

[0033] The present invention also provides a surface slurry, which is composed of a volatile component (i.e., a solvent) and a non-volatile component. The non-volatile component is mainly composed of polyurethane resin and functional powder. The content of functional powder in the non-volatile component does not exceed 25 wt%. The functional powder includes piezoelectric powder, and the content of piezoelectric powder in the non-volatile component is not less than 10 wt%. The piezoelectric powder is silver ion-doped zinc oxide powder, and the doping amount of silver ions is 0.01-0.15.

[0034] As a preferred technical solution:

[0035] As described above, the surface slurry contains silver ion-doped zinc oxide powder with a mesh size of 200-1000 mesh and a piezoelectric strain constant ≥50 pC / N. The preparation process of the silver ion-doped zinc oxide powder is as follows: the zinc oxide powder of the target mesh size is immersed in a solution containing silver ions, and then the immersed powder is heat-treated to obtain the silver ion-doped zinc oxide powder. In the solution containing silver ions, the solute is silver salt, the solvent is water, the concentration is 0.1-5 wt%, the immersion temperature is 40-60℃, the immersion time is 1-4 h, the heat treatment temperature is 300-500℃, and the heat treatment time is 1-3 h.

[0036] As described above, the functional powder in the surface slurry also includes conductive powder; the content of conductive powder in the non-volatile components is not less than 5 wt%.

[0037] As described above, the conductive powder in the surface slurry has a mesh size of 200-1000 mesh and a resistivity ≤1×10⁻⁶. 3 Ω·cm; the conductive powder is graphene.

[0038] The surface layer slurry described above has a viscosity of 1000-3000 CPS.

[0039] For some high anti-penetration requirements or large surface layer thickness scenarios, the coating thickness of the surface layer containing a large amount of piezoelectric powder is limited. If the piezoelectric powder-containing slurry is coated too thick, the product as a whole is prone to be hard. Such hardening problem can usually be alleviated by increasing the thickness of the base cloth layer, which usually plays a decisive role in the softness of the material. However, too thick base cloth layer will cause the product to lose practical value. Therefore, for such scenarios, the thickness of the surface layer containing piezoelectric powder needs to be controlled. The present application also provides another piezoelectric anti-rustling synthetic leather, which coats two or more layers of surface layer instead of a single layer of surface layer to solve the above problems. It should be noted that, in order to avoid pinholes during coating, the surface layer usually needs to be coated in small quantities and multiple times. Here, "single layer" refers to a surface layer coated by using the same component of the surface layer slurry, even if it is coated multiple times during construction, it is still considered as one layer.

[0040] The piezoelectric anti-rustling synthetic leather has at least four layers of structure, including a base cloth layer, an adhesive layer, a bottom surface layer, and a top surface layer. The top surface layer contains functional powder, and the content of the functional powder in the top surface layer is not more than 25wt%. The functional powder includes piezoelectric powder, and the content of the piezoelectric powder in the top surface layer is not less than 10wt%. The piezoelectric powder is silver ion doped zinc oxide powder, and the doping amount of silver ion is 0.01-0.15.

[0041] As a preferred technical solution:

[0042] The piezoelectric anti-rustling synthetic leather as described above, the mesh number of the silver ion doped zinc oxide powder is 200-1000 mesh, and the piezoelectric strain constant is ≥50pC / N. The preparation process of the silver ion doped zinc oxide powder is as follows: the zinc oxide powder with the target mesh number is soaked in a silver ion containing solution, and then the soaked powder is heat treated to obtain the silver ion doped zinc oxide powder. In the silver ion containing solution, the solute is silver salt, the solvent is water, the concentration is 0.1-5wt%, the soaking temperature is 40-60℃, the soaking time is 1-4h, the heat treatment temperature is 300-500℃, and the heat treatment time is 1-3h.

[0043] The piezoelectric anti-rustling synthetic leather as described above, each layer contains conductive powder; from the top surface layer to the base cloth layer, the content of the conductive powder in each layer decreases by 1-2wt% successively, and the content of the conductive powder in the top surface layer and the base cloth layer is not less than 5wt%.

[0044] The piezoelectric anti-rustling synthetic leather as described above, the mesh number of the conductive powder is 200-1000 mesh, and the resistivity is ≤1×10 3 Ω·cm; the conductive powder is graphene.

[0045] The piezoelectric anti-rustling synthetic leather has a top surface layer with a thickness of 0.02-0.15 mm, and the thickness of the top surface layer is not too large, otherwise the product is too hard; the total thickness of the top surface layer and the bottom surface layer is greater than or equal to 0.2 mm, and the bottom surface layer is stacked on the top surface layer, so that the problem of exposed color can be improved without causing the product to be too hard; the thickness of the bonding layer is 0.05-0.1 mm; and the thickness of the base cloth layer is greater than or equal to 0.6 mm.

[0046] The piezoelectric anti-rustling synthetic leather has a top surface layer with a thickness of 0.02-0.15 mm, and the thickness of the top surface layer is not too large, otherwise the product is too hard; the total thickness of the top surface layer and the bottom surface layer is greater than or equal to 0.2 mm, and the bottom surface layer is stacked on the top surface layer, so that the problem of exposed color can be improved without causing the product to be too hard; the thickness of the bonding layer is 0.05-0.1 mm; and the thickness of the base cloth layer is greater than or equal to 0.6 mm.

[0047] The piezoelectric anti-rustling synthetic leather has a top surface layer with a thickness of 0.02-0.15 mm, and the thickness of the top surface layer is not too large, otherwise the product is too hard; the total thickness of the top surface layer and the bottom surface layer is greater than or equal to 0.2 mm, and the bottom surface layer is stacked on the top surface layer, so that the problem of exposed color can be improved without causing the product to be too hard; the thickness of the bonding layer is 0.05-0.1 mm; and the thickness of the base cloth layer is greater than or equal to 0.6 mm.

[0048] (a) placing the non-woven fabric into an impregnation slurry for impregnation, and then coagulating and washing to obtain the base cloth layer, wherein the viscosity of the impregnation slurry is 30,000-50,000 CPS; and the impregnation slurry mainly comprises polyurethane resin and a solvent;

[0049] (b) coating a bonding layer slurry on the surface of the base cloth layer, and then forming a bonding layer on the base cloth layer after the bonding layer slurry is solidified, wherein the viscosity of the bonding layer slurry is 70,000-90,000 CPS; and the bonding layer slurry mainly comprises a bonding layer resin and a solvent, and the function of the bonding layer slurry is to bond the base cloth layer and the surface layer, and the type of the bonding layer resin is not limited in the present application, and the person skilled in the art can adjust the type of the bonding layer resin according to the actual needs without affecting the solving effect of the technical problem of the present application;

[0050] (c) coating a bottom surface layer slurry on the bonding layer, and then forming a bottom surface layer on the bonding layer after the bottom surface layer slurry is solidified, wherein the viscosity of the bottom surface layer slurry is 1,000-3,000 CPS; and the bottom surface layer slurry mainly comprises polyurethane resin and a solvent;

[0051] (d) coating a top surface layer slurry on the bottom surface layer, and then forming a top surface layer on the bottom surface layer after the top surface layer slurry is solidified, so as to obtain the piezoelectric anti-rustling synthetic leather with the structure of base cloth layer-bonding layer-bottom surface layer-top surface layer, wherein the viscosity of the top surface layer slurry is 1,000-3,000 CPS; and the top surface layer slurry mainly comprises polyurethane resin, functional powder and a solvent.

[0052] As a preferred technical solution,

[0053] In the method, the conductive powder is added into the impregnation slurry, the bonding layer slurry, the bottom surface layer slurry and the top surface layer slurry.

[0054] The method as described above, when coating the adhesive layer slurry, the bottom surface layer slurry and the top surface layer slurry, an electric field is applied, the electric field strength is 1-5KV / mm, the electric field direction is parallel to the coating surface, the action time is 10-60s, the electric field is applied to adjust the direction of the conductive powder, thereby improving the contact probability between the contact layers, and reducing the interlayer contact resistance.

[0055] Advantages:

[0056] The present application realizes the improvement of low, medium and high frequency friction vibration abnormal sound by introducing a specific content of piezoelectric powder in the surface layer and through the corresponding mixing, coating and other preparation processes: at low frequency, the mechanical energy is converted into heat energy through the micro friction of piezoelectric powder and resin, at medium and high frequency, the mechanical energy is converted into electrical energy by piezoelectric powder. At the same time, the present application avoids the agglomeration of functional powder and appearance defects by controlling the content of functional powder. The present application not only solves the problem of insufficient inhibition of medium and high frequency abnormal sound in the prior art, but also ensures the stability of material performance and appearance, and effectively improves the anti-abnormal sound effect of synthetic leather. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 The piezoelectric anti-abnormal sound synthetic leather of the present application has the structure of base cloth layer-adhesive layer-surface layer (corresponding to Figure 1 a) and the piezoelectric anti-abnormal sound synthetic leather of the present application has the structure of base cloth layer-adhesive layer-bottom surface layer-top surface layer (corresponding to Figure 1 b);

[0058] Wherein, 1-base cloth layer, 2-adhesive layer, 3-surface layer, 3.1-bottom surface layer, 3.2-top surface layer. DETAILED DESCRIPTION

[0059] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. In addition, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or modifications to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0060] The following are the test methods of the relevant performance indicators in each example and comparative example:

[0061] 1. Piezoelectric strain constant: the piezoelectric coefficient of the sample to be tested is measured by static method, the test environment is 20℃±5℃, humidity 30%RH-75%RH; the instrument used is ZJ-3 type equipment produced by Beijing Jingke Zhichuang Technology Development Co., Ltd.;

[0062] 2. Resistivity: The resistivity of the sample to be tested is measured by the four-probe method, the test environment is 20℃±5℃, the humidity is 30% RH-75% RH, and there is no electrostatic interference; the instrument used is ST2258C type equipment produced by Suzhou Jingge Electronics Co., Ltd.;

[0063] 3. Viscosity: The viscosity of the sample to be tested is measured by a rotary viscometer, the test environment is 25℃±5℃, and the relative humidity is not more than 80%; the instrument used is NDJ-8S type equipment (equipped with No. 3 rotor) produced by Shanghai Pingxuan Scientific Instrument Co., Ltd.;

[0064] 4. Conversion charge: The sample is tested according to GB / T 3389.4-2021 standard, 100N pressure is applied to the sample to be tested and vibrated at a frequency of 500Hz, the conversion charge of the sample is measured by connecting Jiangsu Lian Neng Electronics Technology Co., Ltd. ZK-10 type charge amplifier, and the conversion effect of the sample on the friction vibration mechanical energy is indirectly evaluated;

[0065] 5. Surface voltage: After measuring the conversion charge, the sample is stabilized for 5 seconds, then tested according to GB / T 12703.1 standard, and the surface voltage is measured by Tianjin Nicos Instruments Co., Ltd. RST-400 type triboelectric voltage tester;

[0066] 6. Stick-slip coefficient: The sample is tested according to VDA-230 standard, and the stick-slip coefficient of the sample is measured by Ziegler SSP-04 type stick-slip friction tester in Germany;

[0067] 7. Softness: The sample is tested according to ISO 17235:2015 standard, and the softness of the synthetic leather is measured by Dongguan Zhuo Yue Instrument and Equipment Co., Ltd. BLC ST300 type leather softness tester.

[0068] To demonstrate the effect of the treatment, the following examples use non-woven fabrics of the same specification for treatment research, and the effect can be reproduced in different non-woven fabric specifications. The preparation of synthetic leather non-woven fabric is a conventional process, which can also be obtained by market, which is not detailed here. The components and specifications of non-woven fabrics 1-3 used in each example are as follows:

[0069] Non-woven fabric 1: composed of island fibers, the sea phase is polyethylene, the island phase is PA6, the mass ratio of island and sea is 46:54, the density is 0.2-0.3g / m 3 , the thickness is 0.9mm;

[0070] Non-woven fabric 2: the difference from non-woven fabric 1 is only that the thickness is 1.3mm;

[0071] Non-woven fabric 3: the difference from non-woven fabric 1 is only that the thickness is 1.8mm.

[0072] The method of preparation of the impregnation paste, the tie layer paste, the face layer paste, the bottom face layer paste, the top face layer paste used in the following examples is as follows:

[0073] Impregnation paste without graphene: DMF (N,N-dimethylformamide) is slowly added to Paste 1 while continuously stirring to ensure uniform mixing until the viscosity of the system is reduced to the target viscosity of the impregnation paste;

[0074] Impregnation paste with graphene: DMF is first slowly added to Paste 1 while continuously stirring to ensure uniform mixing; then graphene is added and again thoroughly stirred to ensure uniform mixing; finally, DMF is continued to be slowly added while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the impregnation paste;

[0075] Tie layer paste without graphene: DMF is slowly added to Paste 2 while continuously stirring to ensure uniform mixing until the viscosity of the system is reduced to the target viscosity of the tie layer paste;

[0076] Tie layer paste with graphene: DMF is first slowly added to Paste 2 while continuously stirring to ensure uniform mixing; then graphene is added and again thoroughly stirred to ensure uniform mixing; finally, DMF is continued to be slowly added while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the tie layer paste;

[0077] Face layer paste without graphene: DMF is first slowly added to Paste 3 while continuously stirring to ensure uniform mixing; then piezoelectric powder is added and again thoroughly stirred to ensure uniform mixing; finally, DMF is slowly added while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the face layer paste;

[0078] Face layer paste with graphene: DMF is first slowly added to Paste 3 while continuously stirring to ensure uniform mixing; then piezoelectric powder is added and again thoroughly stirred to ensure uniform mixing; next, DMF is continued to be slowly added while continuously stirring to ensure uniform mixing; again, graphene is added and again thoroughly stirred to ensure uniform mixing; finally, DMF is slowly added while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the face layer paste;

[0079] Bottom face layer paste without graphene: DMF is slowly added to Paste 3 while continuously stirring to ensure uniform mixing until the viscosity of the system is reduced to the target viscosity of the bottom face layer paste;

[0080] The graphene-containing top surface layer slurry: first, slowly add DMF to slurry 3 while continuously stirring to ensure uniform mixing; then add the piezoelectric powder and again stir thoroughly to mix uniformly; then continue to slowly add DMF while continuously stirring to ensure uniform mixing; then add graphene and again stir thoroughly to mix uniformly; finally, slowly add DMF while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the top surface layer slurry;

[0081] The graphene-free top surface layer slurry: first, slowly add DMF to slurry 3 while continuously stirring to ensure uniform mixing; then add the piezoelectric powder and again stir thoroughly to mix uniformly; finally, slowly add DMF while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the top surface layer slurry;

[0082] The graphene-containing top surface layer slurry: first, slowly add DMF to slurry 3 while continuously stirring to ensure uniform mixing; then add the piezoelectric powder and again stir thoroughly to mix uniformly; then continue to slowly add DMF while continuously stirring to ensure uniform mixing; then add graphene and again stir thoroughly to mix uniformly; finally, slowly add DMF while continuously stirring to ensure uniform mixing until the viscosity of the entire system is reduced to the target viscosity required for the top surface layer slurry;

[0083] Among them, slurry 1, slurry 2, slurry 3 are commercially available: the manufacturer of slurry 1 is Shanghai HuiDe Technology Co., Ltd., the brand is HDD-8060HT, and the viscosity is 80000-140000 CPS; the manufacturer of slurry 2 is Shanghai HuiDe Technology Co., Ltd., the brand is HDA-4030H, and the viscosity is 80000-140000 CPS; the manufacturer of slurry 3 is Shanghai HuiDe Technology Co., Ltd., the brand is HDS-3030YB, and the viscosity is 80000-140000 CPS;

[0084] Uniform mixing is achieved by stirring. If the stirring speed is too low, the mixing will not be sufficient, affecting the performance and functional stability of the final material. If the stirring speed is too high, safety hazards will easily occur. The stirring speed needs to be adjusted according to the conventional process, and the skilled person in the art can select an appropriate processing window according to the mixing results and processing safety under this formula. For example, the stirring frequency when preparing the impregnation slurry can be selected to be 30-50 Hz, the stirring frequency when preparing the bonding layer slurry can be selected to be 30-50 Hz, and the stirring frequency when preparing the surface layer slurry, the bottom surface layer slurry, and the top surface layer slurry can be selected to be 40-60 Hz.

[0085] The silver ion-containing solution used in the following examples is composed of silver nitrate and water.

[0086] Example A1

[0087] A preparation method of piezoelectric powder, the specific steps are as follows:

[0088] The zinc oxide powder is soaked in a silver ion-containing solution, and then the soaked powder is subjected to heat treatment, and the piezoelectric powder is obtained; wherein the concentration of the silver ion-containing solution is 0.1wt%, the soaking temperature is 60℃, the soaking time is 1h, the heat treatment temperature is 500℃, and the heat treatment time is 1h;

[0089] The prepared piezoelectric powder is silver ion-doped zinc oxide powder, the doping amount of silver ion is 0.01, the mesh number of the piezoelectric powder is 200 mesh, and the piezoelectric strain constant of the piezoelectric powder is 50pC / N.

[0090] Example A2

[0091] A preparation method of piezoelectric powder, the specific steps are as follows:

[0092] The zinc oxide powder is soaked in a silver ion-containing solution, and then the soaked powder is subjected to heat treatment, and the piezoelectric powder is obtained; wherein the concentration of the silver ion-containing solution is 1wt%, the soaking temperature is 40℃, the soaking time is 4h, the heat treatment temperature is 400℃, and the heat treatment time is 2h;

[0093] The prepared piezoelectric powder is silver ion-doped zinc oxide powder, the doping amount of silver ion is 0.09, the mesh number of the piezoelectric powder is 400 mesh, and the piezoelectric strain constant of the piezoelectric powder is 100pC / N.

[0094] Example A3

[0095] The zinc oxide powder is soaked in a silver ion-containing solution, and then the soaked powder is subjected to heat treatment, and the piezoelectric powder is obtained; wherein the concentration of the silver ion-containing solution is 5wt%, the soaking temperature is 50℃, the soaking time is 2h, the heat treatment temperature is 300℃, and the heat treatment time is 3h;

[0096] The prepared piezoelectric powder is silver ion-doped zinc oxide powder, the doping amount of silver ion is 0.15, the mesh number of the piezoelectric powder is 1000 mesh, and the piezoelectric strain constant of the piezoelectric powder is 120pC / N.

[0097] Example B1

[0098] A preparation method of piezoelectric anti-rustling synthetic leather, the specific steps are as follows:

[0099] (1) preparing impregnation slurry, adhesive layer slurry and surface layer slurry;

[0100] The viscosity of the impregnation slurry is 30,000 CPS, the viscosity of the adhesive layer slurry is 70,000 CPS, and the viscosity of the topcoat slurry is 1,000 CPS. None of the impregnation slurry, adhesive layer slurry, or topcoat slurry contains graphene. The piezoelectric powder in the topcoat slurry is the piezoelectric powder of Example A1.

[0101] (2) Preparation of piezoelectric anti-noise synthetic leather;

[0102] (a) The nonwoven fabric 2 is immersed in the impregnation slurry for impregnation, and then solidified and washed with water to obtain the base fabric layer;

[0103] The thickness of the base fabric layer is 1 mm;

[0104] (b) Apply an adhesive layer slurry to the surface of the base fabric layer, and after the adhesive layer slurry cures, an adhesive layer is formed on the base fabric layer;

[0105] The thickness of the adhesive layer is 0.08 mm;

[0106] (c) Apply a top layer paste to the adhesive layer. After the top layer paste cures, it forms a top layer on the adhesive layer, thus obtaining piezoelectric anti-noise synthetic leather.

[0107] The thickness of the surface layer is 0.05 mm, and the content of piezoelectric powder in the surface layer is 10 wt%.

[0108] like Figure 1 As shown in Figure a, the final piezoelectric anti-noise synthetic leather consists of a top layer 3, an adhesive layer 2, and a base fabric layer 1 from top to bottom; the conversion charge of the top layer of the piezoelectric anti-noise synthetic leather is 474pC, the surface voltage of the top layer of the piezoelectric anti-noise synthetic leather is 15V; the slip coefficient of the piezoelectric anti-noise synthetic leather is level 5, and the softness is 3.6mm.

[0109] Example B2

[0110] A method for preparing piezoelectric anti-noise synthetic leather, the specific steps of which are as follows:

[0111] (1) Prepare impregnation slurry, bonding layer slurry, and surface layer slurry;

[0112] The viscosity of the impregnation slurry is 40,000 CPS, the viscosity of the adhesive layer slurry is 80,000 CPS, and the viscosity of the topcoat slurry is 2,000 CPS. None of the impregnation slurry, adhesive layer slurry, or topcoat slurry contains graphene. The piezoelectric powder in the topcoat slurry is the piezoelectric powder of Example A2.

[0113] (2) Preparation of piezoelectric anti-noise synthetic leather;

[0114] (a) The nonwoven fabric 3 is immersed in the impregnation slurry for impregnation, and then solidified and washed with water to obtain the base fabric layer;

[0115] The thickness of the base layer is 1.5mm;

[0116] (b) coating the surface of the base layer with the adhesive layer slurry, and forming an adhesive layer on the base layer after the adhesive layer slurry is solidified;

[0117] The thickness of the adhesive layer is 0.1mm;

[0118] (c) coating the adhesive layer with the surface layer slurry, and forming a surface layer on the adhesive layer after the surface layer slurry is solidified, thereby obtaining the piezoelectric anti-rustling synthetic leather with the structure of base layer-adhesive layer-surface layer;

[0119] The thickness of the surface layer is 0.1mm, and the content of the piezoelectric powder in the surface layer is 15wt%.

[0120] The converted charge of the surface layer of the piezoelectric anti-rustling synthetic leather finally prepared is 1603pC, the surface voltage of the surface layer of the piezoelectric anti-rustling synthetic leather is 26V, the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 3, and the softness of the piezoelectric anti-rustling synthetic leather is 2.6mm.

[0121] Example B3

[0122] A preparation method of a piezoelectric anti-rustling synthetic leather, and the specific steps are as follows:

[0123] (1) preparing the impregnation slurry, the adhesive layer slurry, and the surface layer slurry;

[0124] The viscosity of the impregnation slurry is 50000CPS, the viscosity of the adhesive layer slurry is 90000CPS, and the viscosity of the surface layer slurry is 3000CPS; none of the impregnation slurry, the adhesive layer slurry, and the surface layer slurry contains graphene, and the piezoelectric powder in the surface layer slurry is the piezoelectric powder of Example A3;

[0125] (2) preparing the piezoelectric anti-rustling synthetic leather;

[0126] (a) placing the non-woven fabric 1 into the impregnation slurry for impregnation, and then coagulating and washing to obtain a base layer;

[0127] The thickness of the base layer is 0.6mm;

[0128] (b) coating the surface of the base layer with the adhesive layer slurry, and forming an adhesive layer on the base layer after the adhesive layer slurry is solidified;

[0129] The thickness of the adhesive layer is 0.05mm;

[0130] (c) coating the adhesive layer with the surface layer slurry, and forming a surface layer on the adhesive layer after the surface layer slurry is solidified, thereby obtaining the piezoelectric anti-rustling synthetic leather with the structure of base layer-adhesive layer-surface layer;

[0131] The thickness of the surface layer is 0.15mm, and the content of the piezoelectric powder in the surface layer is 20wt%.

[0132] The conversion charge of the surface layer of the piezoelectric anti-rustling synthetic leather prepared finally is 3622 pC, and the surface voltage of the piezoelectric anti-rustling synthetic leather is 30 V; the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 1 level, and the softness is 4.5 mm.

[0133] Example B4

[0134] A preparation method of piezoelectric anti-rustling synthetic leather, and the difference from example B1 is that in step (c), the coating process parameters of the surface layer slurry are adjusted, so that the thickness of the surface layer is 0.2 mm.

[0135] The conversion charge of the surface layer of the piezoelectric anti-rustling synthetic leather prepared finally is 1237 pC, and the surface voltage of the piezoelectric anti-rustling synthetic leather is 21 V; the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 4 level, and the softness is 3.3 mm.

[0136] As can be seen from the comparison between example B4 and example B1, the thickness of the surface layer should not be too large, otherwise the product as a whole will be too hard.

[0137] Example B5

[0138] A preparation method of piezoelectric anti-rustling synthetic leather, and the difference from example B1 is that graphene is additionally added in the impregnation slurry, the adhesive layer slurry and the surface layer slurry, the mesh number of the graphene is 600 meshes, the resistivity of the graphene is 1 x 10 3 Ω·cm, the content of the graphene in the base cloth layer is 8 wt%, the content of the graphene in the adhesive layer is 9 wt%, and the content of the graphene in the surface layer is 10 wt%.

[0139] The conversion charge of the surface layer of the piezoelectric anti-rustling synthetic leather prepared finally is 463 pC, and the surface voltage of the piezoelectric anti-rustling synthetic leather is 11 V; the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 5 level, and the softness is 3.6 mm.

[0140] Compared with example B1, the surface voltage of the surface layer of the piezoelectric anti-rustling synthetic leather in example B5 is reduced, because the graphene is added as a conductive powder in each layer, and the content of the graphene decreases by 1 wt% from the surface layer to the base cloth layer. This design builds a smooth electric energy release path, so that the electric energy converted by the piezoelectric powder can be transferred in time, reducing the excessive surface voltage caused by the retention of electric energy.

[0141] Example B6

[0142] A preparation method of piezoelectric anti-rustling synthetic leather, and the difference from example B5 is that the content of the graphene in the base cloth layer is 8 wt%, the content of the graphene in the adhesive layer is 8 wt%, and the content of the graphene in the surface layer is 8 wt%.

[0143] The final piezoelectric anti-rustling synthetic leather has a surface layer with a converted charge of 471 pC and a surface voltage of 14 V. The piezoelectric anti-rustling synthetic leather has a stick-slip coefficient of 4 and a softness of 3.6 mm.

[0144] Example B7

[0145] A piezoelectric anti-rustling synthetic leather is prepared by the method of Example B5, except that the content of graphene in the base layer is 8 wt%, the content of graphene in the adhesive layer is 11 wt%, and the content of graphene in the surface layer is 14 wt%.

[0146] The final piezoelectric anti-rustling synthetic leather has a surface layer with a converted charge of 473 pC and a surface voltage of 14 V. The piezoelectric anti-rustling synthetic leather has a stick-slip coefficient of 4 and a softness of 3.5 mm.

[0147] Compared with Example B5, the surface voltage of the surface layer of the piezoelectric anti-rustling synthetic leather in Example B6 and Example B7 is higher. In Example B6, the content of graphene in each layer is the same, and the difference in content between adjacent two layers is 0 wt%. As a result, the current is concentrated in the surface layer with the smallest resistance, the local current density is too high, the electric energy of the surface layer cannot be effectively conducted to the entire synthetic leather, the electric energy is retained, and the friction characteristics are unstable. In Example B7, the difference in content of graphene between adjacent two layers is 3 wt%, which makes the interface resistance between adjacent two layers too large, the electric energy conduction is blocked, the electric energy is also retained, and the surface voltage is increased.

[0148] Example B8

[0149] A piezoelectric anti-rustling synthetic leather is prepared by the method of Example B5, except that an electric field is applied when coating the adhesive layer slurry, the electric field strength is 1 KV / mm, the electric field direction is parallel to the coating surface, and the action time is 10 s.

[0150] The final piezoelectric anti-rustling synthetic leather has a surface layer with a converted charge of 443 pC and a surface voltage of 8 V. The piezoelectric anti-rustling synthetic leather has a stick-slip coefficient of 4 and a softness of 3.6 mm.

[0151] As can be seen from the comparison between Example B8 and Example B5, applying an electric field when coating the adhesive layer slurry can adjust the direction of the conductive powder (graphene), increase the contact probability between layers, reduce the interlayer contact resistance, make the electric energy conduction smoother, reduce the retention of electric energy, and thus reduce the surface voltage.

[0152] Example B9

[0153] A preparation method of piezoelectric anti-abnormal sound synthetic leather, and the difference from example B1 is that graphene is additionally added in the impregnation slurry, the adhesive layer slurry and the surface layer slurry, the mesh number of the graphene is 1000 meshes, the resistivity of the graphene is 1x10 3 Ω·cm, the content of the graphene in the base fabric layer is 5wt%, the content of the graphene in the adhesive layer is 7wt%, and the content of the graphene in the surface layer is 9wt%; an electric field is applied when the adhesive layer slurry is coated, the electric field strength is 5KV / mm, the direction of the electric field is parallel to the coating surface, and the action time is 60s.

[0154] The converted charge amount of the surface layer of the finally prepared piezoelectric anti-abnormal sound synthetic leather is 459pC, and the surface voltage of the surface layer of the piezoelectric anti-abnormal sound synthetic leather is 6V; the stick-slip coefficient of the piezoelectric anti-abnormal sound synthetic leather is 5 levels, and the softness is 3.6mm.

[0155] As can be seen from the comparison between comparative example B9 and example B1, graphene is added as a conductive powder in each layer, and the content of the graphene decreases by 2wt% from the surface layer to the base fabric layer, and an electric field is applied when the adhesive layer slurry is coated, which can significantly reduce the surface voltage.

[0156] Comparative example 1

[0157] A preparation method of synthetic leather, and the difference from example B1 is only that the piezoelectric powder is replaced by zinc oxide powder, the mesh number of the zinc oxide powder is 200 meshes, and the piezoelectric strain constant of the zinc oxide powder is 10pC / N.

[0158] The converted charge amount of the surface layer of the finally prepared synthetic leather is 148pC, and the surface voltage of the surface layer of the synthetic leather is 12V; the stick-slip coefficient of the synthetic leather is 8 levels, and the softness is 3.6mm.

[0159] Comparative example 1 and example B1, the converted charge amount of the surface layer of the synthetic leather is significantly reduced, the stick-slip coefficient of the synthetic leather is significantly increased, and the anti-abnormal sound effect is significantly deteriorated, because the zinc oxide powder used in comparative example 1 is not doped with silver ions, the piezoelectric strain constant is only 10pC / N, the oxygen vacancy defects exist in the crystal lattice, the continuity of the piezoelectric is destroyed, the mechanical energy cannot be effectively converted into electrical energy, the mechanical energy cannot be improved by consumption, and the converted charge amount of the surface layer is low, and the corresponding surface voltage is also reduced.

[0160] Comparative example 2

[0161] A preparation method of synthetic leather, and the difference from example B1 is only that the amount of piezoelectric powder is adjusted, and the content of the piezoelectric powder in the surface layer is 8wt%.

[0162] The final synthetic leather surface layer conversion charge amount is 223pC, the surface voltage of the synthetic leather surface layer is 14V; the synthetic leather stick-slip coefficient is 7 levels, and the softness is 3.6mm.

[0163] Compared with Example B1, the conversion charge amount of the synthetic leather surface layer of Comparative Example 2 decreases significantly, the stick-slip coefficient increases significantly, and the anti-abnormal sound effect deteriorates significantly, because the content of the surface layer piezoelectric powder in Comparative Example 2 is too low, which cannot effectively convert the mechanical vibration energy into electrical energy, and cannot fully consume the vibration energy, so it is difficult to solve the abnormal sound problem.

[0164] Example C1

[0165] A method for preparing a piezoelectric anti-abnormal sound synthetic leather, the specific steps are as follows:

[0166] (1) preparing impregnation slurry, adhesive layer slurry, bottom surface layer slurry, and top surface layer slurry;

[0167] The viscosity of the impregnation slurry is 30000CPS, the viscosity of the adhesive layer slurry is 70000CPS, the viscosity of the bottom surface layer slurry is 1000CPS, and the viscosity of the top surface layer slurry is 1000CPS; none of the impregnation slurry, the adhesive layer slurry, the bottom surface layer slurry, and the top surface layer slurry contains graphene, and the piezoelectric powder in the top surface layer slurry is the piezoelectric powder of Example A1;

[0168] (2) preparing a piezoelectric anti-abnormal sound synthetic leather;

[0169] (a) placing the non-woven fabric 2 into the impregnation slurry for impregnation, and then coagulating and washing to obtain a base cloth layer;

[0170] The thickness of the base cloth layer is 1mm;

[0171] (b) coating the adhesive layer slurry on the surface of the base cloth layer, and forming an adhesive layer on the base cloth layer after the adhesive layer slurry is solidified;

[0172] The thickness of the adhesive layer is 0.08mm;

[0173] (c) coating the bottom surface layer slurry on the adhesive layer, and forming a bottom surface layer on the adhesive layer after the bottom surface layer slurry is solidified;

[0174] The thickness of the bottom surface layer is 0.1mm;

[0175] (d) coating the top surface layer slurry on the bottom surface layer, and forming a top surface layer on the bottom surface layer after the top surface layer slurry is solidified, thereby obtaining a piezoelectric anti-abnormal sound synthetic leather with the structure of base cloth layer-adhesive layer-bottom surface layer-top surface layer;

[0176] The thickness of the top surface layer is 0.05mm, and the content of the piezoelectric powder in the top surface layer is 25wt%.

[0177] As shown in Figure 1 The final piezoelectric anti-rustling synthetic leather is composed of the top layer 3, the adhesive layer 2 and the base cloth layer 1 from top to bottom, and the top layer 3 is composed of the top layer 3.2 and the bottom layer 3.1 from top to bottom; the conversion charge of the top layer of the piezoelectric anti-rustling synthetic leather is 905pC, the surface voltage of the top layer of the piezoelectric anti-rustling synthetic leather is 18V; the piezoelectric anti-rustling synthetic leather has a stick-slip coefficient of 4 and a softness of 3.3mm.

[0178] Example C2

[0179] A preparation method of a piezoelectric anti-rustling synthetic leather, the specific steps are as follows:

[0180] (1) preparing the impregnation slurry, the adhesive layer slurry, the bottom layer slurry and the top layer slurry;

[0181] The viscosity of the impregnation slurry is 40000CPS, the viscosity of the adhesive layer slurry is 80000CPS, the viscosity of the bottom layer slurry is 3000CPS, and the viscosity of the top layer slurry is 3000CPS; none of the impregnation slurry, the adhesive layer slurry, the bottom layer slurry and the top layer slurry contains graphene, and the piezoelectric powder in the top layer slurry is the piezoelectric powder of Example A2;

[0182] (2) preparing the piezoelectric anti-rustling synthetic leather;

[0183] (a) placing the non-woven fabric 3 into the impregnation slurry for impregnation, and then coagulating and washing to obtain the base cloth layer;

[0184] The thickness of the base cloth layer is 1.5mm;

[0185] (b) coating the adhesive layer slurry on the surface of the base cloth layer, and forming the adhesive layer on the base cloth layer after the adhesive layer slurry is solidified;

[0186] The thickness of the adhesive layer is 0.1mm;

[0187] (c) coating the bottom layer slurry on the adhesive layer, and forming the bottom layer on the adhesive layer after the bottom layer slurry is solidified;

[0188] The thickness of the bottom layer is 0.05mm;

[0189] (d) coating the top layer slurry on the bottom layer, and forming the top layer on the bottom layer after the top layer slurry is solidified, thereby obtaining the piezoelectric anti-rustling synthetic leather with the structure of base cloth layer-adhesive layer-bottom layer-top layer;

[0190] The thickness of the top layer is 0.15mm, and the content of the piezoelectric powder in the top layer is 10wt%.

[0191] The conversion charge of the top surface layer of the piezoelectric anti-rustling synthetic leather prepared finally is 1639pC, the surface voltage of the top surface layer of the piezoelectric anti-rustling synthetic leather is 26V; the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 3, and the softness is 2.5mm.

[0192] Example C3

[0193] A preparation method of a piezoelectric anti-rustling synthetic leather, and the specific steps are as follows:

[0194] (1) preparing impregnation slurry, adhesive layer slurry, bottom surface layer slurry and top surface layer slurry;

[0195] The viscosity of the impregnation slurry is 50000CPS, the viscosity of the adhesive layer slurry is 90000CPS, the viscosity of the bottom surface layer slurry is 2000CPS, and the viscosity of the top surface layer slurry is 2000CPS; none of the impregnation slurry, the adhesive layer slurry, the bottom surface layer slurry and the top surface layer slurry contains graphene, and the piezoelectric powder in the top surface layer slurry is the piezoelectric powder of Example A3;

[0196] (2) preparing a piezoelectric anti-rustling synthetic leather;

[0197] (a) placing the non-woven fabric 1 into the impregnation slurry for impregnation, and then coagulating and washing to obtain a base cloth layer;

[0198] The thickness of the base cloth layer is 0.6mm;

[0199] (b) coating the adhesive layer slurry on the surface of the base cloth layer, and forming an adhesive layer on the base cloth layer after the adhesive layer slurry is solidified;

[0200] The thickness of the adhesive layer is 0.05mm;

[0201] (c) coating the bottom surface layer slurry on the adhesive layer, and forming a bottom surface layer on the adhesive layer after the bottom surface layer slurry is solidified;

[0202] The thickness of the bottom surface layer is 0.2mm;

[0203] (d) coating the top surface layer slurry on the bottom surface layer, and forming a top surface layer on the bottom surface layer after the top surface layer slurry is solidified, i.e. obtaining a piezoelectric anti-rustling synthetic leather with the structure of base cloth layer-adhesive layer-bottom surface layer-top surface layer;

[0204] The thickness of the top surface layer is 0.13mm, and the content of the piezoelectric powder in the top surface layer is 20wt%.

[0205] The conversion charge of the top surface layer of the piezoelectric anti-rustling synthetic leather prepared finally is 3122pC, the surface voltage of the top surface layer of the piezoelectric anti-rustling synthetic leather is 29V; the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 1, and the softness is 4.6mm.

[0206] Example C4

[0207] The preparation method of the piezoelectric anti-abnormal sound synthetic leather is different from that of Example C1 in that: when the top surface layer slurry is prepared, the addition amount of the piezoelectric powder is adjusted, and the content of the piezoelectric powder in the top surface layer is 10wt%; graphene is additionally added in the impregnation slurry, the bonding layer slurry, the bottom surface layer slurry and the top surface layer slurry, the mesh number of the graphene is 400 meshes, the resistivity of the graphene is 1×10 3 Ω·cm, the content of the graphene in the base cloth layer is 5wt%, the content of the graphene in the bonding layer is 7wt%, the content of the graphene in the bottom surface layer is 9wt%, and the content of the graphene in the top surface layer is 10wt%.

[0208] The converted charge amount of the top surface layer of the piezoelectric anti-abnormal sound synthetic leather finally prepared is 467pC, and the surface voltage of the top surface layer of the piezoelectric anti-abnormal sound synthetic leather is 11V; the stick-slip coefficient of the piezoelectric anti-abnormal sound synthetic leather is 5 levels, and the softness is 3.3mm.

[0209] Compared with Example C1, the surface voltage of the surface layer of the piezoelectric anti-abnormal sound synthetic leather in Example C4 is reduced, because graphene is added as a conductive powder in each layer, and the content of the graphene decreases by 1-2wt% from the top surface layer to the base cloth layer, which designs a smooth electric energy release path, so that the electric energy converted by the piezoelectric powder can be transferred in time, reducing the excessive surface voltage caused by the retention of electric energy. Compared with Example C1, the content of the piezoelectric powder in the top surface layer in Example C4 is reduced, resulting in a decrease in the surface layer charge conversion amount and an increase in the stick-slip coefficient.

[0210] Example C5

[0211] The preparation method of the piezoelectric anti-abnormal sound synthetic leather is different from that of Example C1 in that: when the top surface layer slurry is prepared, the addition amount of the piezoelectric powder is adjusted, and the content of the piezoelectric powder in the top surface layer is 10wt%; graphene is additionally added in the impregnation slurry, the bonding layer slurry, the bottom surface layer slurry and the top surface layer slurry, the mesh number of the graphene is 200 meshes, the resistivity of the graphene is 1×10 3 Ω·cm, the content of the graphene in the base cloth layer is 5wt%, the content of the graphene in the bonding layer is 6wt%, the content of the graphene in the bottom surface layer is 7wt%, and the content of the graphene in the top surface layer is 8wt%; an electric field is applied when the bonding layer slurry is coated, the electric field strength is 2KV / mm, the electric field direction is parallel to the coating surface, and the action time is 20s.

[0212] The converted charge amount of the top surface layer of the piezoelectric anti-rustling synthetic leather prepared finally is 441 pC, the surface voltage of the top surface layer of the piezoelectric anti-rustling synthetic leather is 8 V; the stick-slip coefficient of the piezoelectric anti-rustling synthetic leather is 5 levels, and the softness is 3.3 mm.

[0213] Compared with example C1, the surface voltage of the surface layer of the piezoelectric anti-rustling synthetic leather in example C5 is reduced, because graphene is added as a conductive powder in each layer, and the content of graphene decreases by 1 wt% from the top surface layer to the base cloth layer. This design builds a smooth electric energy release path, so that the electric energy converted by the piezoelectric powder can be transferred in time, reducing the excessive surface voltage caused by the retention of electric energy. Compared with example C1, the content of piezoelectric powder in the top surface layer of example C5 is reduced, resulting in a decrease in the charge conversion amount of the top surface layer and an increase in the stick-slip coefficient.

[0214] Comparative example 3

[0215] A method for preparing synthetic leather, and the difference from example C1 is only that the amount of piezoelectric powder added is adjusted, and the content of piezoelectric powder in the top surface layer is 30 wt%.

[0216] In comparative example 3, due to the excessive amount of piezoelectric powder, the piezoelectric powder is easy to agglomerate and produce interface defects, not only the anti-rustling effect is poor, but also the surface layer is not good in appearance, the appearance defects are serious, and finally the synthetic leather is scrapped.

Claims

1. A piezoelectric anti-rustling synthetic leather, characterized by, The piezoelectric anti-rustling synthetic leather has a structure of at least four layers, including a base cloth layer, a bonding layer, a bottom surface layer and a top surface layer; the top surface layer contains functional powder, and the content of the functional powder in the top surface layer is not more than 25 wt%; the functional powder includes piezoelectric powder, and the content of the piezoelectric powder in the top surface layer is not less than 10 wt%. The piezoelectric powder is silver ion doped zinc oxide powder, and the doping amount of silver ions is 0.01-0.

15.

2. The piezoelectric anti-noise synthetic leather according to claim 1, characterized by, The mesh number of the silver ion doped zinc oxide powder is 200-1000 mesh, and the piezoelectric strain constant is greater than or equal to 50 pC / N; the preparation process of the silver ion doped zinc oxide powder is as follows: The zinc oxide powder with a target mesh number is soaked in a solution containing silver ions, and then the soaked powder is subjected to heat treatment, so as to obtain the silver ion doped zinc oxide powder; in the solution containing silver ions, the solute is silver salt, the solvent is water, the concentration is 0.1-5 wt%, the soaking temperature is 40-60°C, the soaking time is 1-4 h, the heat treatment temperature is 300-500°C, and the heat treatment time is 1-3 h.

3. The piezoelectric anti-noise synthetic leather according to claim 1, characterized by, Each layer contains conductive powder; from the top surface layer to the base cloth layer, the content of the conductive powder in each layer decreases by 1-2 wt% successively, and the content of the conductive powder in the top surface layer and the base cloth layer is not less than 5 wt%.

4. The piezoelectric anti-noise synthetic leather according to claim 3, characterized by, The mesh number of the conductive powder is 200-1000 mesh, and the resistivity is ≤1×10 3 Ω·cm; the conductive powder is graphene.

5. The piezoelectric anti-noise synthetic leather according to claim 1, characterized by, The thickness of the top surface layer is 0.02-0.15 mm; the total thickness of the top surface layer and the bottom surface layer is greater than or equal to 0.2 mm; the thickness of the bonding layer is 0.05-0.1 mm; and the thickness of the base cloth layer is greater than or equal to 0.6 mm.

6. The piezoelectric anti-noise synthetic leather according to any one of claims 1 to 5, characterized by, The conversion charge of the top surface layer of the piezoelectric anti-rustling synthetic leather is 905-3122 pC, and the surface voltage of the top surface layer of the piezoelectric anti-rustling synthetic leather is 18-29 V; the piezoelectric anti-rustling synthetic leather has a sliding coefficient of 1-4 levels and a softness of 2.5-4.6 mm.

7. The method of preparing the piezoelectric anti-noise synthetic leather as claimed in claim 1, characterized in that, The piezoelectric anti-rustling synthetic leather is prepared by the following steps: (a) placing a non-woven fabric into an impregnation slurry for impregnation, and then performing coagulation and water washing to obtain a base cloth layer, wherein the viscosity of the impregnation slurry is 30,000-50,000 CPS; (b) coating a bonding layer slurry on the surface of the base cloth layer, and then forming a bonding layer on the base cloth layer after the bonding layer slurry is solidified, wherein the viscosity of the bonding layer slurry is 70,000-90,000 CPS; (c) coating a bottom surface layer slurry on the bonding layer, and then forming a bottom surface layer on the bonding layer after the bottom surface layer slurry is solidified, wherein the viscosity of the bottom surface layer slurry is 1,000-3,000 CPS; (d) coating a top surface layer slurry on the bottom surface layer, and then forming a top surface layer on the bottom surface layer after the top surface layer slurry is solidified, so as to obtain a piezoelectric anti-rustling synthetic leather with a structure of base cloth layer-bonding layer-bottom surface layer-top surface layer, wherein the viscosity of the top surface layer slurry is 1,000-3,000 CPS.

8. The method of claim 7, wherein, The conductive powder is added to the impregnation slurry, the bonding layer slurry, the bottom surface layer slurry and the top surface layer slurry.

9. The method of claim 8, wherein, An electric field is applied when at least one of the bonding layer slurry, the bottom surface layer slurry and the top surface layer slurry is coated, and the electric field strength is 1-5 KV / mm, the direction of the electric field is parallel to the coating surface, and the action time is 10-60 s.

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