Composition, pressure-sensitive film layer, pressure sensing structure and dispersing agent

Abstract

The invention discloses a dispersing agent which is applied to a pressure-sensitive material. The chemical structural formula of the dispersing agent is # imgabs0 #, an Ar1 group is selected from at least one of # imgabs1 # and # imgabs2 #, an Ar2 group is selected from at least one of # imgabs3 # and # imgabs4 #, and x and y are respectively greater than zero. The invention also provides a composition containing the dispersant, a pressure-sensitive film layer formed by the composition, and a pressure sensing structure containing the pressure-sensitive film layer.

Description

Technical Field

[0001] The present application relates to a dispersant applied to a pressure-sensitive material, a composition using the dispersant, a pressure-sensitive film layer formed by the composition, and a pressure sensing structure including the pressure-sensitive film layer. Background Art

[0002] Pressure sensing structures are often used in electronic products to sense pressure values. Therefore, in order to improve the user experience of electronic products, the sensitivity requirements of pressure sensing structures are becoming higher and higher. Summary of the invention

[0003] In view of this, it is necessary to provide a dispersant for use in pressure-sensitive materials, which is beneficial to improving the sensitivity of the pressure-sensitive materials.

[0004] In addition, it is also necessary to provide a composition comprising the above dispersant, a pressure-sensitive film layer formed by the composition, and a pressure sensing structure comprising the pressure-sensitive film layer.

[0005] The first aspect of the present application provides a dispersant, which is used in a pressure-sensitive material. The chemical structure of the dispersant is The Ar1 group is selected from and At least one of the following, wherein the Ar2 group is selected from and At least one of x and y is greater than zero.

[0006] The second aspect of the present application provides a composition, comprising the dispersant as described above, carbon black, a polymer resin and a solvent.

[0007] A third aspect of the present application provides a pressure-sensitive film layer formed by coating and curing the composition as described above.

[0008] A fourth aspect of the present application provides a pressure sensing structure, comprising a circuit substrate and the pressure-sensitive film layer as described above disposed on the circuit substrate, wherein the pressure-sensitive film layer is electrically connected to the circuit substrate.

[0009] Since the dispersant has a narrow molecular weight distribution, it is beneficial to obtain the stabilizing force of the ion-bonded anchoring group of stable length, which is beneficial to the stable formation of a 3D structure network between the anchoring group and the carbon black particles, which is beneficial to optimize the spacing between the carbon blacks and avoid the phenomenon of local agglomeration of carbon black, enhance the dispersion effect, and form multiple mesh-like micro and stable conductive bridges with the carbon black particles, so as to facilitate the perception of pressure changes when the pressure-sensitive film layer receives a small pressure, and improve the sensitivity and reliability of the sensing structure. At the same time, multiple mesh-like micro and stable conductive bridges are also beneficial to reducing the amount of carbon black added, without the need for a large amount of carbon black to ensure electrical connection. Compared with the method of directly sensing pressure changes through multi-dimensional direct contact between carbon and carbon, the sensitivity of the sensing structure is improved, and the reduction in the amount of carbon black added is also beneficial to the flatness of the appearance of the pressure-sensitive film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A cross-sectional schematic diagram of a pressure sensing structure according to an embodiment of the present application.

[0011] Figure 2 This is an electron microscope image of the pressure-sensitive film layer of Example 1 provided in the present application.

[0012] Figure 3 This is an electron microscope image of the pressure-sensitive film layer of Example 2 provided in the present application.

[0013] Figure 4 This is an electron microscope image of the pressure-sensitive film layer of Example 3 provided in the present application.

[0014] Main component symbols

[0015]

[0016] DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0019] The dispersant of one embodiment of the present application is used in a pressure-sensitive material. The chemical structural formula of the dispersant is Wherein, the Ar1 group is selected from and At least one of the following, wherein the Ar2 group is selected from and In some embodiments, in the dispersant, The molecular weight of the group can be from 7000 to 11000, The molecular weight of the group The ratio of the molecular weights of the groups may be from 1:3 to 1:7.

[0020] The present application also provides a composition according to an embodiment, wherein the composition comprises the above-mentioned dispersant, carbon black, a polymer resin and a solvent.

[0021] In this embodiment, in the composition, the content of the dispersant may be 5% to 10%, the content of the carbon black may be 5% to 10%, the content of the polymer resin may be 20% to 50%, and the content of the solvent may be 40% to 48%. The viscosity of the composition may be 4000 cps to 20000 cps.

[0022] In the above composition, the dispersant has a narrow molecular weight distribution, which is conducive to obtaining the stabilizing force of the ionic bonding type anchoring group with a stable length, thereby facilitating the stable formation of a 3D structural network between the anchoring group and the carbon black particles, and forming multiple network-like micro and stable conductive bridges with the carbon black particles, which is conducive to avoiding inconsistent spacing between carbon blacks and local agglomeration of carbon blacks, enhancing the dispersion effect, and at the same time, it is also conducive to reducing the amount of carbon black added, without the need for a large amount of carbon black to ensure electrical connection.

[0023] Furthermore, in some embodiments, the ratio of the content of the polymer resin to the content of the carbon black may be 5:2 to 9:2.

[0024] The carbon black is conductive particles, and may include but is not limited to at least one of acetylene black, Super-P, Ketjen black, and the like.

[0025] The polymer resin may include but is not limited to at least one of epoxy resin and acrylic resin, etc. The molecular weight of the polymer resin may be between 30,000 and 100,000 (including the end value).

[0026] The solvent may include but is not limited to at least one of aromatic hydrocarbons, aliphatic hydrocarbons, alcohol ethers, esters, ketones, alcohols, vegetable oils and mineral oils, such as but not limited to at least one of diethylene glycol monoethyl ether and its acetate, terpineol, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether, diethylene glycol butyl ether acetate and isophorone. In the present application, the solvent may be selected from at least one of diethylene glycol monoethyl ether and its acetate, so as to facilitate the mixing and dispersion of the components.

[0027] In some embodiments, the composition may further include an auxiliary agent. The auxiliary agent may be, but is not limited to, at least one of a defoamer, a leveling agent, a plasticizer, a thickener, and a thixotropic agent, or other dispersants, such as, but not limited to, a silane coupling agent.

[0028] The present application also provides a pressure-sensitive film layer according to an embodiment of the present invention, wherein the pressure-sensitive film layer is formed by coating and curing the above-mentioned composition, and the pressure-sensitive film layer can be used as a pressure-sensitive material.

[0029] Specifically, the coating method may be, but is not limited to, printing, spraying, and the like.

[0030] In some embodiments, the pressure-sensitive film layer may have a thickness of 7 micrometers to 20 micrometers.

[0031] The pressure-sensitive film layer formed by the above-mentioned composition, since the dispersant has a narrow molecular weight distribution, is conducive to obtaining the stabilizing force of the ionic bonding type anchoring group with a stable length, which is conducive to the stable formation of a 3D structure network between the anchoring group and the carbon black particles, and is conducive to optimizing the spacing between carbon blacks and avoiding the phenomenon of local agglomeration of carbon black, thereby enhancing the dispersion effect and forming a plurality of network-like micro and stable conductive bridges with the carbon black particles, so as to facilitate sensing pressure changes when the pressure-sensitive film layer is subjected to slight pressure, thereby improving sensitivity and reliability. At the same time, a plurality of network-like micro and stable conductive bridges are also conducive to reducing the amount of carbon black added, and there is no need to use a large amount of carbon black to ensure electrical connection. Compared with the method of directly sensing pressure changes through multi-dimensional direct contact between carbon and carbon, the sensitivity is improved. In addition, the reduction in the amount of carbon black added is also beneficial to the smoothness of the appearance of the pressure-sensitive film layer. Among them, The molecular weight and The molecular weight ratio of carbon black is 1:3 to 1:7, which is conducive to optimizing the spacing between carbon blacks while better cooperating with the polymer resin to improve the adhesion and film-forming properties of the composition, thereby ensuring the film-forming effect (such as the continuity of the film layer) of the pressure-sensitive film layer while ensuring the sensitivity of the pressure-sensitive film layer. The viscosity of the composition is 4000cps to 20000cps, combined with the reduction of the amount of carbon black added, which is conducive to reducing the required leveling time when forming the pressure-sensitive film layer, thereby saving work hours and preventing the pressure-sensitive film layer from being contaminated by air-suspended particles in the wet film state.

[0032] When the ratio of the content of the polymer resin in the pressure-sensitive film layer to the content of the carbon black is 5:2 to 9:2, it is beneficial to avoid cracks in the pressure-sensitive film layer when it is slightly bent (i.e., the bending angle is less than 60°), and it is beneficial to fully coat the carbon black while ensuring the stability and reliability of the electrical connection to avoid the carbon black falling off from the pressure-sensitive film layer to contaminate the product and affect the surface smoothness of the pressure-sensitive film layer.

[0033] See also Figure 1 The present application further provides a pressure sensing structure 100 according to an embodiment, comprising a circuit substrate 10 and the pressure sensitive film layer 30 disposed on the circuit substrate 10. The pressure sensitive film layer 30 is electrically connected to the circuit substrate 10.

[0034] In some embodiments, the pressure-sensitive film layer 30 may be electrically connected to the circuit substrate 10 through, but not limited to, a silver wire 40 .

[0035] In some embodiments, the pressure sensing structure 100 further includes a packaging layer 50, and the packaging layer 50 covers the pressure sensitive film layer 30 and the silver wire 40. The packaging layer 50 may include but is not limited to a resin material.

[0036] In the pressure sensing structure 100, the multiple mesh-shaped micro and stable conductive bridges in the pressure-sensitive film layer 30 are also beneficial for optimizing the consistency of adjacent bridge resistance values ​​to optimize the differential voltage performance and the discreteness of the sensitivity of the sensing structure, reduce the noise of the overall circuit, and improve the reliability of the sensing structure.

[0037] The present application is specifically described below through examples.

[0038] Example 1

[0039] By weight percentage, 6% of the dispersant (structural formula: in, The molecular weight of the group is 9000, The molecular weight and The molecular weight ratio is 1:3), 7.5% of Orion carbon black Printex L, 40% of phenoxy modified epoxy resin (manufacturer: Huntsman Advanced Materials), 5% of additives (1.5% of leveling agent BYK-300 and 3.5% of defoaming agent BYK-024) and 41.5% of diethylene glycol monoethyl ether are mixed uniformly to form a composition.

[0040] Example 2

[0041] The difference from Example 1 is that: The molecular weight and The molecular weight ratio is 1:5.

[0042] Example 3

[0043] The difference from Example 1 is that: The molecular weight and The molecular weight ratio is 1:7.

[0044] The composition in the above embodiments is printed to form a pressure-sensitive film layer with a thickness of 10 μm±2 μm and an initial length of 100 mm, and the initial resistance of the pressure-sensitive film layer is measured by a 4-wire ohmmeter. The pressure-sensitive film layer is then clamped and stretched by a stretching machine to a length of 100.5 mm, i.e., the length after stretching. The resistance of the pressure-sensitive film layer at this time is read by a 4-wire ohmmeter as the resistance after stretching. The sensitivity coefficient GF=((resistance after stretching-initial resistance) / initial resistance) / ((length after stretching-initial length) / length after stretching) is calculated and recorded in the following Table 1.

[0045] For the corresponding pressure-sensitive film layer of each of the above embodiments, two resistance values ​​R1 and R2 are measured at any two locations, and the bridge offset is calculated as (R1 / (R1+R2)-0.5)*1000, that is, the BOS standard deviation, and is recorded in the following Table 1. For each embodiment, the BOS standard deviation is obtained 100 times continuously, and the standard deviation is further calculated as the noise mean, and is recorded in Table 1.

[0046] Table 1

[0047]

[0048]

[0049] The surface of the pressure-sensitive film layer formed in the above embodiments was observed through a microscope, wherein: Figures 2 to 4 They are electron microscope images of the pressure-sensitive film layers corresponding to Examples 1 to 3. It can be seen from the figures that the degree of particle aggregation in the pressure-sensitive film layer of the present application is very small.

[0050] The above is only the preferred implementation mode of the present application, and is not any form of limitation on the present application. Although the present application has been disclosed as the preferred implementation mode as above, it is not used to limit the present application. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent implementation modes without departing from the scope of the technical solution of the present application. However, any simple modification, equivalent change and modification made to the above implementation modes based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A dispersant, characterized in that: The dispersant is applied to pressure-sensitive materials, and the chemical structural formula of the dispersant is The Ar1 group is selected from and At least one of the following, wherein the Ar2 group is selected from and At least one of x and y is greater than zero.

2. The dispersant according to claim 1, characterized in that In the dispersant, the The molecular weight of the group is 7,000 to 11,000.

3. The dispersant according to claim 1 or 2, characterized in that Said The molecular weight of the group is The ratio of the molecular weights of the groups is 1:3 to 1:

7.

4. A composition, characterized in that The method comprises the dispersant as described in any one of claims 1 to 3, carbon black, a polymer resin and a solvent.

5. The composition according to claim 4, characterized in that In the composition, by weight percentage, the content of the dispersant is 5% to 10%, the content of the carbon black is 5% to 10%, the content of the polymer resin is 20% to 50%, and the content of the solvent is 40% to 48%.

6. The composition according to claim 5, characterized in that The ratio of the content of the polymer resin to the content of the carbon black is 5:2 to 9:

2.

7. A composition as claimed in any one of claims 4 to 6, characterized in that The polymer resin includes at least one of epoxy resin and acrylic resin, and the molecular weight of the polymer resin is 30,000 to 100,000.

8. A pressure-sensitive film layer, characterized in that: It is formed by coating and curing the composition as claimed in any one of claims 4 to 7.

9. The pressure-sensitive film layer according to claim 8, characterized in that: The thickness of the pressure-sensitive film layer is 7 micrometers to 20 micrometers.

10. A pressure sensing structure, characterized in that: The invention comprises a circuit substrate and the pressure-sensitive film layer as claimed in claim 9 which is arranged on the circuit substrate, and the pressure-sensitive film layer is electrically connected to the circuit substrate.

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