Arrangement method of particles, method of manufacturing anisotropic functional adhesive film, functional particles, and method of manufacturing the same

Abstract

The present application relates to a particle arrangement method, a method for manufacturing an anisotropic functional adhesive film, a functional particle, and a method for manufacturing the same. The particle arrangement method of the present application includes: forming a composite structure including an adhesive layer and a plurality of particles on an extensible substrate, at least a portion of each of the particles being embedded in the adhesive layer; and biaxially stretching the extensible substrate carrying the composite structure so that projections of each of the particles on at least one plane of the substrate formed by a first direction and a second direction are separated from each other. The method for manufacturing an anisotropic functional adhesive film of the present application employs the particle arrangement method of the present application. The functional particle of the present application includes a core material and a metal layer covering the core material; the core material is formed of a polymer including a unit based on a mono(meth)acrylate-based monomer having an epoxy group and a unit based on a monomer having two or more vinyl groups; and a metal in the metal layer is chemically bonded to the polymer.

Description

Technical Field

[0001] This application relates to the field of particle arrangement methods, and more particularly to a particle arrangement method, anisotropic functional films and a method for manufacturing anisotropic functional films using the particle arrangement method, functional particles and a method for manufacturing the same. Background Technology

[0002] In applications such as materials science, chemistry, and biology, it is often necessary to arrange particles (e.g., organic particles, inorganic particles, or organic / inorganic composite particles) in an orderly manner to endow the material carrying the particles with specific functions, such as catalysis, light filtering, light absorption, electrical / magnetic / thermal transport, gas adsorption, medicine, and electrical / magnetic recording.

[0003] However, the arrangement of particles often depends on the structure and composition of the particles themselves and the target material. Furthermore, particle arrangement often incurs high costs, which limits the development of high-performance products and increases production costs. This is particularly prominent in the field of anisotropic functional films.

[0004] Anisotropic functional adhesives have numerous applications in the electronics industry, particularly in various terminals such as tablets, laptops, digital cameras, mobile phones, wearable electronic devices, and virtual reality devices, where they are widely used for integrated circuit packaging. With the miniaturization and increasing functionality of these terminals, the requirements for anisotropic functional adhesives are becoming increasingly stringent. Anisotropic functional adhesives include anisotropic conductive adhesives, anisotropic magnetic adhesives, and anisotropic thermal conductive adhesives. For example, anisotropic conductive adhesives have important applications in displays and cameras, such as electrical interconnection between ICs, FPCs / COFs, and display devices in terminal products. Especially with the development of display devices such as OLEDs, QLEDs, Mini-LEDs, and Micro-LEDs, the performance requirements for anisotropic conductive adhesives are becoming increasingly demanding. Anisotropic magnetic adhesives are crucial in radio frequency modules, achieving excellent signal performance through differences in magnetic or dielectric properties in different directions. Anisotropic thermal conductive adhesives can achieve anisotropic heat dissipation effects on high-density integrated circuit boards or devices in mobile phones. Here, anisotropy refers to the ability to conduct electricity, magnetism, heat, etc. in a specific direction (e.g., the direction perpendicular to the surface of the adhesive film, i.e., the Z direction) and not to conduct electricity in other directions (e.g., the direction parallel to the surface of the adhesive film, i.e., the XY direction).

[0005] The main principle of this anisotropic functional adhesive film is to add functional particles to the adhesive and form it into an adhesive film. During the curing process, it becomes conductive in the Z direction, while it only plays an adhesive function in the XY direction but does not have conductive properties.

[0006] The arrangement of functional particles in anisotropic functional films and the controllable preparation of the functional particles themselves are the core technologies that this field focuses on.

[0007] Regarding the arrangement of functional particles, random and matrix distribution methods are mainly used in this field. Random distribution methods are difficult to achieve precise distribution of functional particles (poor uniformity and adjustability), especially in high-precision device assembly. Given the poor reliability and difficulty in adjusting the hardness of the functional layer of traditional functional particles, there is often a risk of conduction obstruction (especially short circuits in conductive films), resulting in poor performance of anisotropic functional films containing randomly distributed functional particles. Therefore, matrix distribution methods are commonly used to improve precision. Many methods for matrix distribution have been reported in the prior art, such as magnetron sputtering, template methods, photolithography, and magnetic separation. However, existing matrix distribution methods suffer from high cost, low yield, and poor adjustability of particle size distance. Furthermore, existing matrix distribution methods sometimes damage the functional layer on the outer side of the functional particles. Therefore, for particle matrix distribution methods, especially for the matrix distribution methods of functional particles in anisotropic functional films, the industry is still constantly exploring new solutions to simultaneously solve the technical problems of poor adjustability and uniformity of functional particle distribution in films, complex processes, low yield, and impaired particle function.

[0008] On the other hand, regarding traditional functional particles, polymer particles such as polystyrene-based particles or polymethyl methacrylate-based particles are commonly used as the base in this field. However, the adjustability of the hardness, particle size, and particle size distribution of such polymer particles is low, and the surface roughness is uncontrollable. Furthermore, these polymer particles are inert, and therefore, chemical plating is typically used to form a metal layer on their surface. However, such plating presents environmental problems, and the process is complex and costly. In addition, the resulting metal coating is not reliable and is prone to peeling. Therefore, for the functional particles themselves, there is room for improvement in balancing properties such as morphology, hardness, size, and distribution while enhancing the reliability of the surface metal layer. Summary of the Invention

[0009] In view of this, a particle arrangement method is proposed, which can easily distribute various particles in an orderly manner without damaging the particles themselves. The process is simple, yields high quality, and is suitable for large-scale production.

[0010] A method for manufacturing anisotropic functional adhesive films is also proposed, which can easily make the functional particles uniformly distributed and adjust the distribution mode of the functional particles in the adhesive film as needed, without damaging the functional layer of the functional particles, with simple process and high yield, and is convenient for large-scale production.

[0011] A functional particle is also proposed. The polymer core of this particle has a flexible and tunable molecular chain structure and strong adhesion to the metal layer. Therefore, the functional particle can have the desired morphology and hardness as needed, and the metal layer is not easily detached, ensuring high reliability. Simultaneously, the functional particle has uniform size. Therefore, this functional particle is particularly suitable for inclusion in anisotropic functional films (arbitrarily distributed randomly or in a matrix distribution), enabling the anisotropic functional film to possess excellent conductivity, precision, and functional stability, and to be suitable for various application scenarios.

[0012] A method for manufacturing functional particles is also proposed, which can easily obtain functional particles with highly adjustable surface morphology and hardness, high metal layer reliability, and uniform size without the need to specifically construct protrusion structures on the particle surface. This method is environmentally friendly, has a simple process, and is easy to mass-produce.

[0013] A functional particle, obtained through a specific method, is also proposed. This particle possesses a flexible and tunable molecular chain structure in its polymer core material and exhibits strong adhesion to the metal layer. Consequently, the functional particle can be customized to achieve the desired morphology and hardness, and the metal layer is resistant to detachment, ensuring high reliability. Furthermore, the functional particle exhibits uniform size. Therefore, this functional particle is particularly suitable for inclusion in anisotropic functional films (arbitrarily distributed randomly or in a matrix pattern), enabling the anisotropic functional film to possess excellent conductivity, precision, and functional stability, making it suitable for various applications.

[0014] An anisotropic functional film is also proposed, which, due to containing the aforementioned functional particles of this application, possesses excellent conductivity, precision, and functional stability, and is suitable for various application scenarios.

[0015] In a first aspect, embodiments of this application provide a method for arranging particles, the method comprising:

[0016] A composite structure comprising an adhesive layer and a plurality of particles is formed on a stretchable substrate, wherein at least a portion of each particle is embedded in the adhesive layer;

[0017] The extensible substrate supporting the composite structure is biaxially stretched such that the projections of each particle onto a plane formed by a first direction and a second direction of the substrate are separated from each other.

[0018] In this case, various particles can be easily distributed in an orderly manner without damaging the particles themselves. The process is simple and has a high yield, making it easy for large-scale production.

[0019] According to the first aspect, in a first possible implementation of the particle arrangement method, the first direction and the second direction are perpendicular to each other in the plane they form.

[0020] In this case, it is easier to distribute various particles in an orderly manner, which is more convenient for large-scale production.

[0021] According to the first aspect, in one or two possible implementations of the particle arrangement method, the plane formed by the first direction and the second direction is parallel to the surface of the substrate.

[0022] In this case, it is even easier to distribute various particles in an orderly manner, which further facilitates large-scale production.

[0023] According to the first aspect, in any one of the first to third possible implementations of the particle arrangement method, the ratio of the degree of orientation in the transverse direction to the degree of orientation in the longitudinal direction in the substrate subjected to biaxial stretching is 1 to 9.9.

[0024] In this case, the adjustability of the particle matrix is ​​more suitable, and the particle arrangement method of this application is suitable for different applications.

[0025] According to the first aspect, in any one of the first to fourth possible implementations of the particle arrangement method, the ratio of the degree of orientation in the transverse direction to the degree of orientation in the longitudinal direction in the biaxially stretched substrate is 1.2 to 9.

[0026] In this case, the adjustability of the particle matrix is ​​more suitable and easier to adjust, and the particle arrangement method of this application is suitable for different applications.

[0027] According to the first aspect, in any of the first to fifth possible implementations of the particle arrangement method, the ratio of the degree of orientation in the transverse direction to the degree of orientation in the longitudinal direction in the biaxially stretched substrate is 1.5 to 8.5.

[0028] In this case, the adjustability of the particle matrix is ​​more suitable and easier to adjust, and the particle arrangement method of this application is suitable for different applications.

[0029] According to the first aspect, in any of the first to sixth possible implementations of the particle arrangement method, the orientation angle relative to the transverse direction in the substrate subjected to biaxial stretching is 0 to 90°.

[0030] In this case, the adjustability of the particle matrix is ​​more suitable, and the particle arrangement method of this application is suitable for different applications.

[0031] According to the first aspect, in any one of the first to seventh possible implementations of the particle arrangement method, the first direction is the transverse direction of the substrate, and the second direction is the longitudinal direction of the substrate.

[0032] In this case, it is even easier to distribute various particles in an orderly manner, which further facilitates large-scale production.

[0033] According to the first aspect, in any of the first to eighth possible implementations of the particle arrangement method, the composite structure is formed by: applying an adhesive coating liquid that does not contain the particles onto the stretchable substrate and drying it to form an adhesive layer, and then covering the adhesive layer with the particles in such a way that at least a portion of them are embedded in the adhesive layer.

[0034] In this case, the matrix distribution of particles can be controlled more effectively.

[0035] According to the first aspect, in any of the first to eighth possible implementations of the particle arrangement method, the composite structure is formed by applying an adhesive coating liquid containing the particles onto the stretchable substrate and drying it.

[0036] In this case, it is easier to arrange the particles.

[0037] According to the first aspect, in any one of the first to ten possible implementations of the particle arrangement method, the extendable substrate is at least one selected from polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polypropylene resin, and polymethyl methacrylate resin.

[0038] In this case, the particle matrix distribution can be made more easily in an adjustable manner.

[0039] According to the first aspect, in any of the first to eleven possible implementations of the particle arrangement method, the particles are functional particles, the functional particles comprising a core material and a metal layer covering the core material;

[0040] The core material is formed of a polymer comprising units based on mono(meth)acrylate monomers with epoxy groups and units based on monomers with two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

[0041] In this case, the particle arrangement method of this application can be specifically used to prepare anisotropic functional films.

[0042] According to the first aspect, in any of the first to twelfth possible implementations of the particle arrangement method, the adhesive resin contained in the adhesive layer is a thermosetting epoxy resin or a thermosetting (meth)acrylic resin.

[0043] In this case, it is more advantageous to fix the particles and make it easier to distribute the particle matrix in an adjustable manner.

[0044] According to the first aspect, in any of the first to thirteen possible implementations of the particle arrangement method, the thickness of the adhesive layer is 1 / 6 to 1 / 1 of the average particle size before the biaxial stretching is performed.

[0045] In this case, it is more advantageous to fix the particles and make it easier to distribute the particle matrix in an adjustable manner.

[0046] According to the first aspect, in any of the first to fourteenth possible implementations of the particle arrangement method, the thickness tolerance of the adhesive layer is less than 0.05 μm before the biaxial stretching is performed.

[0047] In this case, the dimensional stability of the resulting particle matrix is ​​improved, further increasing the yield.

[0048] According to the first aspect, in any of the first to fifteen possible implementations of the particle arrangement method, when performing the biaxial stretching, the stretching ratio is 1 to 20 times and the stretching speed is 2 to 40 mm / min.

[0049] In this case, it is more advantageous to distribute the particle matrix in an adjustable manner, while better ensuring high dimensional stability and further improving the yield.

[0050] According to the first aspect, in any of the first to sixteen possible implementations of the particle arrangement method, after the biaxial stretching is performed, the distance between the projections of the particles onto a plane formed by the first and second directions of the substrate is greater than 0 μm and less than 25 μm.

[0051] In this case, the adjustability of the particle matrix is ​​more suitable, and the particle arrangement method of this application is suitable for different applications.

[0052] Secondly, embodiments of this application provide a method for manufacturing an anisotropic functional adhesive film, the method comprising:

[0053] Functional particles with functional conductivity are arranged by means of any one of the first to seventeen possible implementations of the first aspect to form a stretched composite structure on a substrate.

[0054] Another adhesive layer is formed on the stretched composite structure.

[0055] In this context, the manufacturing method of the anisotropic functional film of this application can easily make the functional particles uniformly distributed and can adjust the distribution mode of the functional particles in the film as needed, without damaging the functional layer of the functional particles, with simple process and high yield, and is convenient for large-scale production.

[0056] According to the second aspect, in a first possible implementation of the method for manufacturing the anisotropic functional adhesive film, the adhesive layer included in the composite structure has the same composition as the other adhesive layer.

[0057] In this case, the adhesion of the anisotropic functional adhesive film of this application can be further improved.

[0058] According to the second aspect, in one or two possible implementations of the method for manufacturing the anisotropic functional adhesive film, the adhesive layer included in the composite structure is fused with the other adhesive layer to form a structure that encapsulates the functional particles.

[0059] In this case, the adhesiveness and mechanical properties of the anisotropic functional adhesive film of this application can be further improved.

[0060] According to the second aspect, in any one of the first to third possible implementations of the method for manufacturing the anisotropic functional adhesive film, the overall thickness of the anisotropic functional adhesive film is 10 to 50 μm.

[0061] In this context, the anisotropic functional film of this application better ensures excellent conductivity, precision, and functional stability.

[0062] According to the second aspect, in any one of the first to fourth possible implementations of the method for manufacturing the anisotropic functional adhesive film, the thickness of the anisotropic functional adhesive film is 3 to 15 times the average particle size of the functional particles.

[0063] In this context, the anisotropic functional film of this application better ensures excellent conductivity, precision, and functional stability.

[0064] According to the second aspect, in any one of the first to fifth possible implementations of the method for manufacturing the anisotropic functional adhesive film, the total mass of the functional particles is 1 to 15% by mass relative to the total mass of the adhesive.

[0065] In this context, the anisotropic functional film of this application better ensures excellent conductivity, precision, and functional stability.

[0066] Thirdly, embodiments of this application provide a functional particle, wherein the functional particle comprises a core material and a metal layer covering the core material;

[0067] The core material is formed of a polymer comprising units based on mono(meth)acrylate monomers with epoxy groups and units based on monomers with two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

[0068] In this context, the polymer core material of the functional particles in this application has a flexible and adjustable molecular chain structure and strong adhesion to the metal layer. Therefore, the functional particles can have the desired morphology and hardness as needed, and the metal layer is not easily detached, resulting in high reliability. Simultaneously, the functional particles have uniform size. Therefore, these functional particles are suitable for inclusion in anisotropic functional films, enabling the anisotropic functional films to possess excellent conductivity, precision, and functional stability, and to be suitable for various application scenarios.

[0069] According to the third aspect, in a first possible implementation of the functional particles, the average particle size of the functional particles is 1 to 15 μm.

[0070] In this case, the functional particles are more suitable for use in anisotropic functional films.

[0071] According to the third aspect, in one or two possible implementations of the functional particles, the functional particles have a rough surface.

[0072] In this case, the functional particles are more suitable for use in anisotropic functional films.

[0073] According to the third aspect, in a third possible implementation of the functional particles, the rough surface has a rough structure formed by a plurality of burr structures.

[0074] In this case, the functional particles have a more suitable surface morphology and can provide better conductivity when used in anisotropic functional films.

[0075] According to the third aspect, in any of the first to fourth possible implementations of the functional particles, the K30% hardness of the core material is 500–2500 N / mm. 2 .

[0076] In this case, the functional particles are more suitable for use in anisotropic functional films.

[0077] According to the third aspect, in any one of the first to fifth possible implementations of the functional particles, the degree of crosslinking of the polymer is 0.5 to 20%.

[0078] In this case, the functional particles are more suitable for use in anisotropic functional films.

[0079] According to the third aspect, in any of the first to sixth possible implementations of the functional particles, the ratio of the units based on the epoxy-containing mono(meth)acrylate monomers is 80 to 98 by mass relative to all structural units of the polymer.

[0080] In this case, the functional particles have a more suitable morphology and / or hardness, and can provide stronger adhesion to the metal layer and greater reliability.

[0081] According to the third aspect, in any of the first to seventh possible implementations of the functional particles, the ratio of the units based on monomers with two or more vinyl groups is 2 to 20 by mass relative to all structural units of the polymer.

[0082] In this case, the functional particles have a more suitable degree of softness and hardness.

[0083] According to the third aspect, in any of the first to eighth possible implementations of the functional particles, the metal layer is a layer comprising at least one of gold, silver, copper, nickel, palladium and platinum.

[0084] In this case, the functional particles can provide superior conductivity and functional stability when used in anisotropic functional films.

[0085] Fourthly, embodiments of this application provide a method for manufacturing functional particles according to any one of the first to ninth possible implementations of the third aspect, wherein the method includes:

[0086] At least a mono(meth)acrylate monomer with an epoxy group and a monomer with two or more vinyl groups are added to a dispersion medium containing a surfactant for polymerization to form initial polymer particles.

[0087] An activator is used to activate the epoxy groups on the surface of the initial polymer particles to form activated polymer particles;

[0088] The activated polymer particles are added to an aqueous solution of a metal compound and a metal layer is formed on its surface using a reducing agent.

[0089] In this context, the manufacturing method of this application can easily obtain functional particles with highly adjustable morphology and hardness, high reliability of the metal layer, and uniform size. It is environmentally friendly, has a simple process, and is easy to mass-produce.

[0090] According to the fourth aspect, in a first possible implementation of the method for manufacturing the functional particles, the mass ratio of the activator to the initial polymer particles is 1:50 to 1:200.

[0091] In this case, the manufacturing method of this application can make the surface of the initial polymer particles have more suitable active groups, thereby making the metal layer more reliable without increasing the production cost.

[0092] According to the fourth aspect, in the first or second possible implementation of the method for manufacturing the functional particles, the activator is at least one selected from ozone, hydrogen sulfide, acetic acid, oxalic acid, sulfuric acid, nitric acid, and hydrochloric acid.

[0093] In this case, the manufacturing method of this application can more effectively activate the initial polymer particles.

[0094] According to the fourth aspect, in any one of the first to third possible implementations of the method for manufacturing the functional particles, the metal compound is at least one selected from chloroauric acid tetrahydrate, silver nitrate, silver chloride, copper nitrate, copper sulfate, nickel sulfate, palladium chloride, palladium nitrate, and chloroplatinic acid.

[0095] In this case, the manufacturing method of this application can form a metal layer more effectively.

[0096] Fifthly, embodiments of this application provide a functional particle, characterized in that the functional particle is obtained by a manufacturing method comprising the following:

[0097] At least a mono(meth)acrylate monomer with an epoxy group and a monomer with two or more vinyl groups are added to a dispersion medium containing a surfactant for polymerization to form initial polymer particles.

[0098] An activator is used to activate the epoxy groups on the surface of the initial polymer particles to form activated polymer particles;

[0099] The activated polymer particles are added to an aqueous solution of a metal compound and a metal layer is formed on its surface using a reducing agent.

[0100] In this context, the functional particles of this application are obtained through a specific method, resulting in a flexible and tunable molecular chain structure of the polymer core material and strong adhesion to the metal layer. Therefore, the functional particles can be customized to achieve the desired morphology and hardness, and the metal layer is not easily detached, ensuring high reliability. Furthermore, the functional particles have uniform size. Consequently, these functional particles are particularly suitable for inclusion in anisotropic functional films, enabling the anisotropic functional films to possess excellent conductivity, precision, and functional stability, and to be suitable for various application scenarios.

[0101] In a sixth aspect, embodiments of this application provide an anisotropic functional adhesive film, which is a film-like adhesive material comprising an adhesive and functional particles according to any one of the first to ninth possible implementations of the third aspect or functional particles according to the first possible implementation of the fifth aspect.

[0102] In this case, the anisotropic functional film of this application contains functional particles with highly adjustable morphology and hardness, high reliability of the metal layer, and uniform size. Regardless of the arrangement of these functional particles, it can have excellent conductivity, precision, and functional stability, and is suitable for different application scenarios.

[0103] According to the sixth aspect, in a first possible implementation of the anisotropic functional adhesive film, the functional particles are randomly dispersed in the adhesive.

[0104] Under these circumstances, the anisotropic functional film of this application can be formed more easily.

[0105] According to the sixth aspect, in a first possible implementation of the anisotropic functional film, the functional particles are distributed such that their projections onto a plane formed by the first and second directions of the film are separated from each other.

[0106] In this context, the anisotropic functional film of this application can better combine excellent conductivity, precision and functional stability, and is suitable for different application scenarios.

[0107] According to the sixth aspect, in a third possible implementation of the anisotropic functional film, the distance between the projections of the functional particles onto a plane formed by the first and second directions of the film is greater than 0 μm and less than 25 μm.

[0108] In this case, the anisotropic functional film of this application has more suitable adjustability of performance and is suitable for different application scenarios.

[0109] According to the sixth aspect, in any one of the first to fourth possible implementations of the anisotropic functional adhesive film, the thickness of the anisotropic functional adhesive film is 3 to 15 times the average particle size of the functional particles.

[0110] In this context, the anisotropic functional film of this application better ensures excellent conductivity, precision, and functional stability.

[0111] According to the sixth aspect, in any of the first to fifth possible implementations of the anisotropic functional adhesive film, the total mass of the functional particles is 1 to 15% of the total mass relative to the total mass of the adhesive.

[0112] In this case, the anisotropic functional film of this application has superior conductivity, precision and functional stability.

[0113] According to the sixth aspect, in any of the first to sixth possible implementations of the anisotropic functional adhesive film, the adhesive resin contained in the anisotropic functional adhesive film is a thermosetting epoxy resin or a thermosetting (meth)acrylic resin.

[0114] In this case, the anisotropic functional adhesive film of this application further has more suitable adhesion.

[0115] According to the sixth aspect, in any of the first to seventh possible implementations of the anisotropic functional adhesive film, the overall thickness of the anisotropic functional adhesive film is 10 to 50 μm.

[0116] In this context, the anisotropic functional film of this application better ensures excellent conductivity, precision, and functional stability.

[0117] These and other aspects of this application will become more apparent in the description of the following embodiments(s). Attached Figure Description

[0118] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0119] Figure 1 The diagram shows an example of the particle arrangement method of this application (the adhesive portion is omitted in the top view for simplicity).

[0120] Figure 2 An example of a method for manufacturing anisotropic functional adhesive film is shown (the adhesive portion is omitted in the top view for simplicity).

[0121] Figure 3An example of biaxial stretching performed in a multi-stage manner is shown (the adhesive portion is omitted for brevity).

[0122] Figure 4 The illustration shows a specific example of the method for manufacturing the functional particles of this application (using GMA and EDGMA as monomers to form polymer particles, gold as the metal, thiol as the active group, and sodium borohydride NaBH4 as the reducing agent).

[0123] Figure 5 An example of the initial polymer particles of this application is shown (using emulsion polymerization of GMA and EDGMA at 75°C).

[0124] Figure 6 An example of constructing a metal layer on activated polymer particles is shown (the metal is gold, the activated group is thiol, and the reducing agent is sodium borohydride NaBH4).

[0125] Figure 7 The adhesive conductivity principle of an anisotropic conductive film, which is an example of an anisotropic functional adhesive film of this application, is shown. Detailed Implementation

[0126] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0127] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0128] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0129] <First Aspect>

[0130] To address the aforementioned technical problems, this application provides a method for arranging particles, the method comprising:

[0131] A composite structure comprising an adhesive layer and a plurality of particles is formed on a stretchable substrate, wherein at least a portion of each particle is embedded in the adhesive layer;

[0132] The extensible substrate supporting the composite structure is biaxially stretched such that the projections of each particle onto a plane formed by a first direction and a second direction of the substrate are separated from each other.

[0133] In this case, various particles can be easily distributed in an orderly manner without damaging the particles themselves. The process is simple and has a high yield, making it easy for large-scale production.

[0134] In the first aspect of this application, for convenience, the term "Z direction" refers to the direction perpendicular to the surface of the substrate (i.e., the thickness direction), the term "X direction" refers to the transverse direction of the substrate (sometimes also referred to in the art as the width direction, i.e., the TD direction), the term "Y direction" refers to the longitudinal direction of the substrate (sometimes also referred to in the art as the mechanical direction, i.e., the MD direction), and the term "XY direction" refers to the direction parallel to the surface of the substrate. Furthermore, the term "surface of the substrate" is generally understood to refer to the surface used to support the adhesive layer and particles.

[0135] Figure 1 The diagram illustrates an example of the particle arrangement method of this application. It is understood, of course, that the particle arrangement method of this application is not limited to... Figure 1 The example shown.

[0136] The following will describe each step in detail.

[0137] (A composite structure (S-a1) is formed on a stretchable substrate)

[0138] As described above, a composite structure comprising an adhesive layer and a plurality of particles is formed on a stretchable substrate, wherein at least a portion of each particle is embedded in the adhesive layer. As an example, such as... Figure 1 The S-a1 step of the example is shown.

[0139] In step S-a1, there are no particular limitations on the specific type of stretchable substrate, and it can be any known in the art, as long as biaxial stretching described later can be achieved. In some preferred embodiments, from the viewpoint that the particle matrix distribution can be more easily and in an adjustable manner, the stretchable substrate is preferably at least one selected from polyethylene terephthalate resins, polybutylene terephthalate resins, polycarbonate resins, polypropylene resins, and polymethyl methacrylate resins.

[0140] In step S-a1, there are no particular restrictions on the specific type of particles; various particle arrangements can be used, and the arrangement method can be appropriately adjusted according to the specific application of this application. Examples of particles include, but are not limited to: metal particles such as gold, silver, copper, and aluminum; inorganic particles such as silicon, silicon dioxide, alumina, barium sulfate, and iron(III) oxide; organic particles such as styrene polymers, (meth)acrylate polymers, and organosilicon polymers; organic / inorganic composite particles; organic / metal composite particles; and inorganic / metal composite particles. These particles can be used alone or in combination of two or more.

[0141] In step S-a1, there are no particular restrictions on the specific shape of the particles. Examples of shapes include, but are not limited to, spherical, near-spherical, or other regular or irregular shapes.

[0142] In step S-a1, there are no particular restrictions on the average size (e.g., average particle diameter) and distribution of the particles, which can be appropriately adjusted according to the specific application of the particle arrangement method of this application.

[0143] In some preferred embodiments, when the particle arrangement method of this application is used to prepare anisotropic functional films, the particles are preferably functional particles with functional conductivity (e.g., electrical conductivity, magnetic conductivity, thermal conductivity, etc.). In some more preferred embodiments, the functional particles are functional particles as described in the following <Third Aspect> or <Fifth Aspect>, and will not be repeated here.

[0144] In step S-a1, there is no particular limitation on the specific type of adhesive used to form the adhesive layer; various adhesives known in the art can be used. In some preferred embodiments, thermosetting adhesives are preferably used, examples of which include, but are not limited to, epoxy resin-based adhesives, (meth)acrylic resin-based adhesives, isocyanate-based adhesives, silicone resin-based adhesives, polyurethane-based adhesives, etc. Here, "X-based adhesive" means an adhesive formed using a compound X (or polymer) as an adhesive component (e.g., an adhesive resin), which optionally contains other components besides the compound X (or polymer).

[0145] In some preferred embodiments, from the viewpoint of more readily immobilizing the particles and more easily distributing the particle matrix in an adjustable manner, the adhesive resin contained in the adhesive layer is a thermosetting epoxy resin (i.e., the adhesive used in the adhesive layer is a thermosetting epoxy resin-based adhesive) or a thermosetting (meth)acrylate resin (i.e., the adhesive used in the adhesive layer is a (meth)acrylate resin-based adhesive). Here, the term "(meth)acrylate" encompasses (meth)acrylate, (meth)acrylate salts, (meth)acrylate esters, etc.

[0146] In some specific embodiments, when the adhesive used in the adhesive layer is a thermosetting epoxy resin-based adhesive, the adhesive is preferably derived from a solvent-based epoxy resin adhesive coating liquid, and the solvent-based epoxy resin adhesive coating liquid preferably comprises solid epoxy resin, liquid epoxy resin, latent curing agent, toughening agent, and solvent. In some more preferred embodiments, the weight ratio of solid epoxy resin, liquid epoxy resin, latent curing agent, toughening agent, and solvent (solid epoxy resin: liquid epoxy resin: latent curing agent: toughening agent: solvent) is preferably 1:1 to 5:0.05 to 0.2:0.1 to 0.5:3 to 10. In other more preferred embodiments, from the viewpoint of cost reduction, the solvent-based epoxy resin adhesive coating liquid is preferably obtained by means commonly used in the art, by blending and stirring the constituent components until homogeneous.

[0147] The aforementioned solid epoxy resin is any solid epoxy resin known in the art. In some specific embodiments, it is preferably selected from at least one of solid bisphenol epoxy resin, solid phenolic epoxy resin (e.g., o-cresol phenolic epoxy resin), biphenyl epoxy resin, fused ring epoxy resin and dicyclopentadiene phenolic epoxy resin.

[0148] The aforementioned liquid epoxy resin is any liquid epoxy resin known in the art. In some specific embodiments, examples include bisphenol A and bisphenol F epoxy resins. The viscosity of the liquid epoxy resin is preferably between 200 and 5000 cps.

[0149] The aforementioned latent curing agent is any latent curing agent known in the art. In some specific embodiments, it is preferably selected from at least one of boron trifluoride and its ethylamine complex, amines (e.g., 4,4'-diamino-3,3'-diethyldiphenylmethane), imidazoles (e.g., dimethylimidazolium and diphenylimidazolium), and acid anhydrides (e.g., (methyl)tetrahydrophthalic anhydride, (methyl)hexahydrophthalic anhydride, (methyl)nadic anhydride).

[0150] The toughening agents described above are any toughening agents known in the art. In some specific embodiments, examples of toughening agents include, but are not limited to, nitrile rubber toughening agents, silicone toughening agents, polyurethane toughening agents, etc. In other specific embodiments, the toughening agent is a core-shell structure toughening agent or a homogeneous toughening agent. Furthermore, when the weight-average molecular weight of the toughening agent is measurable, the weight-average molecular weight of the toughening agent is preferably between 2000 and 20000. These toughening agents can be used alone or in combination of two or more.

[0151] The solvent is preferably selected from at least one of cyclohexanone, chloroform, ethyl acetate, toluene, dichloromethane, chloroform, tetrahydrofuran, ethylene oxide, acetone and dioxane.

[0152] In some specific embodiments, when the adhesive used in the adhesive layer is a (meth)acrylic resin-based adhesive, the adhesive is preferably derived from a solvent-based (meth)acrylic resin adhesive coating liquid, and the solvent-based (meth)acrylic resin adhesive coating liquid preferably comprises (meth)acrylic resin, crosslinking agent, thermal initiator, toughening agent, polymerization inhibitor, and solvent. In some more preferred embodiments, the weight ratio of (meth)acrylic resin, crosslinking agent, thermal initiator, toughening agent, polymerization inhibitor, and solvent ((meth)acrylic resin: crosslinking agent: thermal initiator: toughening agent: polymerization inhibitor: solvent) is preferably 1:0.1-0.5:0.05-0.2:0.1-0.5:0.05-0.1:3-10. In some more preferred embodiments, from the viewpoint of cost reduction, the solvent-based (meth)acrylic resin adhesive coating liquid is preferably obtained by means commonly used in the art, by blending and stirring the constituent components until homogeneous.

[0153] The aforementioned (meth)acrylic resin is any (meth)acrylic resin known in the art that can be used as an adhesive resin, preferably an oligomer with a (meth)acrylic ester structure, and its weight-average molecular weight is between 2000 and 20000.

[0154] The aforementioned crosslinking agent is any crosslinking agent known in the art. In some specific embodiments, it is preferably a (meth)acrylate containing two or more double bonds. Examples of such (meth)acrylates containing two or more double bonds include, but are not limited to, tricyclodecanedimethylethanol diacrylate, trimethylolpropane trimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,4-butanediol diacrylate, and neopentyl glycol diacrylate. These crosslinking agents can be used alone or in combination of two or more.

[0155] The initiator used in solvent-based (meth)acrylic resin adhesive coating solutions is any free radical initiator known in the art. In some specific embodiments, it is preferably a peroxide initiator. Examples of such peroxide initiators include, but are not limited to, diisobutyryl peroxide, cumyl peroxyneodecanoate, bis(3-methoxybutyl) peroxydicarbonate, bis(ethoxyhexyl) peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, etc. Bis(4-tert-butylcyclohexyl) carbonate, ditetradecyl peroxydicarbonate, tert-butyl peroxide-2-ethylhexanoate, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, tert-amyl peroxide-2-ethylhexyl carbonate, butyl 4,4-bis(tert-butylperoxide)valerate, tert-butyl peroxide, 2,5-di-tert-butylperoxide-2,5-dimethylhexane, di-tert-butyl peroxide, methyl isobutyl ketone peroxide, acetylacetone peroxide, and cyclohexanone peroxide. These initiators can be used alone or in combination of two or more.

[0156] The above-mentioned polymerization inhibitor is any polymerization inhibitor known in the art. In some specific embodiments, it is preferably at least one selected from diethylhydroxylamine, nitrobenzene, hydroquinone, p-hydroxyanisole, and 2,6-di-tert-butyl-p-cresol.

[0157] In step S-a1, in the composite structure, at least a portion of each particle is embedded in the adhesive layer. This means that the particle can be entirely embedded in the adhesive layer, or at least a portion of the particle can protrude beyond the surface of the adhesive layer (wherein, the portion of the particle protruding beyond the surface of the adhesive layer may be coated with adhesive or may not be coated with adhesive).

[0158] In some preferred embodiments, prior to biaxial stretching, the thickness of the adhesive layer in the composite structure is preferably 1 / 6 to 1 / 1 of the average particle size, more preferably 1 / 6 to 1 / 2 of the average particle size, and even more preferably 1 / 6 to 1 / 4 of the average particle size.

[0159] In addition, in some preferred embodiments, the thickness tolerance of the adhesive layer in the composite structure is preferably less than 0.05 μm before biaxial stretching.

[0160] In some specific embodiments, from the viewpoint of being able to more effectively control the matrix distribution of particles, such as Figure 1As shown in the upper part of step S-a1, the composite structure is preferably formed by: applying a particle-free adhesive coating liquid to the stretchable substrate and drying it to form an adhesive layer, and then covering the adhesive layer with the particles, at least a portion of which are embedded in the adhesive layer. In this case, there are no particular limitations on the coating method of the adhesive coating liquid, and the coating methods include, but are not limited to, brush coating, dip coating, spin coating, bar coating, doctor blade coating, curtain coating, screen printing coating, spray coating, slot coating, etc. These coating methods can be used alone or in combination of two or more. Furthermore, in this case, there are no particular limitations on the method of covering the functional particles; for example, coating methods such as dip coating, spray coating, or deposition methods can be used. These covering methods can be used alone or in combination of two or more.

[0161] In other specific embodiments, from the viewpoint that particle arrangement can be made easier, such as Figure 1 As shown in the lower half of step S-a1, the composite structure is preferably formed by applying an adhesive coating liquid containing the particles onto the stretchable substrate and drying it. In this case, the coating method includes, but is not limited to, brush coating, dip coating, spin coating, bar coating, doctor blade coating, curtain coating, screen printing coating, spray coating, slot coating, etc. These coating methods can be used alone or in combination of two or more. Furthermore, there are no particular limitations on the preparation method of the adhesive coating liquid containing the particles; in some preferred embodiments, the adhesive coating liquid containing the particles is preferably prepared by mixing the functional particles with the adhesive coating liquid using methods known in the art.

[0162] In step S-a1, there are no particular restrictions on the distribution of particles in the composite structure. In some preferred embodiments, multiple particles are preferably distributed in a manner in which at least a portion of them are closely arranged.

[0163] In step S-a1, there are no particular limitations on the drying method; any drying method known in the art can be used, such as air drying or oven drying. In some preferred embodiments, the drying temperature is preferably 40–60°C, and the drying time is preferably 0.1–3 hours, more preferably 0.5–2 hours. In this step, when using a thermosetting adhesive, the drying process will not cause the thermosetting adhesive to cure.

[0164] (Biaxial stretching (S-a2))

[0165] As described above, the extensible substrate supporting the aforementioned composite structure is biaxially stretched such that the projections of each particle onto a plane formed by the first and second directions of the substrate are separated from each other. As an example, such as... Figure 1The S-a2 step of the example is shown.

[0166] In this application, "the projection of each particle on at least one plane of the substrate formed by the first and second directions is separated from each other" means that, in addition to the plane formed by the first and second directions, the projections of the particles on at least one other plane of the substrate are also separated from each other.

[0167] In addition, in some preferred embodiments of this application, after biaxial stretching, multiple particles are preferably arranged in a matrix in a single layer at least on a plane formed by the first and second directions of the substrate. However, this does not mean that the actual center of each particle is in the same plane. There is a possibility that the actual center of more than one particle in the matrix is ​​not in the same plane as the actual center of other particles, but the projection of each particle on the plane of the substrate is separated from each other.

[0168] Furthermore, in this application, there are no particular limitations on the first direction and the second direction, or the angle between them, in the biaxially stretched composite structure. In some preferred embodiments, from the viewpoint of facilitating the orderly distribution of various particles and promoting mass production, the first direction and the second direction are preferably perpendicular to each other in the plane they form. In other preferred embodiments, for the same purpose, the plane formed by the first direction and the second direction is parallel to the surface of the substrate. More preferably, the first direction is the transverse direction of the substrate, and the second direction is the longitudinal direction of the substrate.

[0169] It should be noted here that the first and second directions in the biaxially stretched composite structure do not necessarily correspond to the two stretching directions of the biaxial stretch (i.e., the first and second directions correspond to the two stretching directions of the biaxial stretch, or at least one of the first and second directions does not correspond to the two stretching directions of the biaxial stretch).

[0170] In this application, the arrangement of particles can be achieved at low cost through a stretching process, and the projected distance between particles can be adjusted by the degree of stretching and the stretching angle in at least a plane formed by the first direction and the second direction.

[0171] In step S-a2, there are no particular restrictions on the stretching method used; biaxial stretching methods known in the art can be employed. Specifically, fixed-end stretching or free-end stretching can be used.

[0172] In step S-a2, biaxial stretching can be performed along any direction (XY direction) perpendicular to the Z direction of the substrate, as long as the projection of each particle onto at least one plane formed by the first and second directions of the substrate is separated from each other. Furthermore, in this application, the line connecting the centers of the projection circles of any two adjacent particles can form any angle relative to the X direction. For example, as... Figure 1 As shown, the stretching direction can be the X direction and the Y direction (e.g., Figure 1 (as in (S-a2)), or other directions that are at any angle relative to the X direction in the XY direction.

[0173] In step S-a2, there are no special restrictions on the stretching mode; it can be either an aerial stretching mode or an underwater stretching mode.

[0174] In step S-a2, biaxial stretching can be performed simultaneously or sequentially (e.g., stretching in the Y direction first, then stretching in the X direction). Furthermore, the stretching step (step S-a2) can be performed in one stage or in multiple stages (e.g., biaxial stretching can be performed in both the X and Y directions, followed by stretching at a specific angle to adjust the angle, such as...). Figure 2 (As shown in the example). When stretching is performed in multiple stages, for example, the above-described free-end stretching and fixed-end stretching can be combined, or the above-described underwater stretching mode and aerial stretching mode can be combined. Furthermore, when stretching is performed in multiple stages, the stretching ratio (maximum stretching ratio) described later is the product of the stretching ratios of each stage.

[0175] In step S-a2, the stretching temperature can be set to any appropriate value based on factors such as the forming material of the substrate, the specific composition of the particles, and the stretching mode. In some preferred embodiments, the stretching temperature is 40–60°C.

[0176] In some preferred embodiments, when the biaxial stretching is performed, the stretching ratio in each stretching direction (e.g., the X direction, the Y direction, or other directions perpendicular to the Z direction) relative to the original size of the stretchable substrate is preferably 1 to 20 times, more preferably 1 to 10 times.

[0177] In some other preferred embodiments, the biaxial stretching is performed at a stretching speed of 2 to 40 mm / min.

[0178] In some preferred embodiments, after the S-a2 step, the ratio of the orientation degree in the X direction (TD direction) to the orientation degree in the Y direction (MD direction) of the biaxially stretched substrate is preferably 1 to 9.9, for example, it can be 1.2, 1.3, 1.4, 1.5, 1.8, 2.0, 2.2, 2.5, 2.8, 3.0, 3.2, 3.5, 3.8, 4.0, 4.2, 4.5, 4.8, 5.0, 5.2, 5.5, 5.6, 5.8, 6.0, 6.2, 6.4, 6.6, 6.8, 7.0, 7.1, 7.3, 7.6, 7.8, 8.0, 8.1, 8.3, 8.5, 8.8, 9.0, 9.1, 9.3, 9.5, 9.6, 9.8, 9.9, etc. It should be noted here that the range between any two points mentioned above, as well as any errors in engineering implementation, are all within the scope of this application. Furthermore, the ratio of the orientation degree in the X direction (TD direction) to the orientation degree in the Y direction (MD direction) of the biaxially stretched substrate is more preferably 1.2 to 9, more preferably 1.5 to 8.5, even more preferably 1.8 to 8, and even more preferably 2 to 7.8, and even more preferably 2.5 to 7. In these preferred embodiments, particle arrangement can be flexibly performed while suppressing substrate quality degradation, and sometimes costs can be reduced.

[0179] As long as the above-mentioned orientation ratio is met, there are no particular restrictions on the orientation degree of the substrate in the X direction and the orientation degree of the substrate in the Y direction. In some preferred embodiments, the orientation degree of the substrate in the X direction is preferably 1.5 to 8, more preferably 1.8 to 7, even more preferably 2 to 6, and even more preferably 2.5 to 5. In other preferred embodiments, the orientation degree of the substrate in the Y direction is preferably 1.5 to 8, more preferably 1.8 to 7, even more preferably 2 to 6, and even more preferably 2.5 to 5. In these preferred embodiments, the particle arrangement can be more flexibly arranged while suppressing the quality degradation of the substrate.

[0180] Furthermore, in some preferred embodiments, after the S-a2 step, the orientation angle of the substrate relative to the X direction after biaxial stretching is preferably 0–90°, more preferably 0–80°, even more preferably 0–70°, and even more preferably 0–60°. In these preferred embodiments, particle arrangement can be flexibly performed while suppressing substrate quality degradation, and sometimes costs can be reduced.

[0181] In this application, the above-mentioned orientation degree and orientation angle are measured by a molecular orientation meter, such as the MOA-8000 series molecular orientation meter from Oji Keiseki Co., Ltd.

[0182] In some preferred embodiments, after the biaxial stretching is performed, the distance between the projections of the particles onto the substrate in a plane formed by the first and second directions (i.e., the distance between the two closest points between two adjacent projections) is greater than 0 μm and less than 25 μm, more preferably 1 μm to 15 μm, and even more preferably 2 μm to 10 μm.

[0183] (Specific examples)

[0184] In some particularly preferred embodiments, the particle arrangement method of this application includes the following steps:

[0185] S-a1 Steps: ① Coating an adhesive layer on the surface of the stretchable substrate: Apply a solution-based adhesive to the substrate and bake at 40–60°C for 30–120 min. The thickness of the resulting adhesive layer is 1 / 4 to 1 / 2 of the particle diameter, with a thickness tolerance of 0.05 μm; ② Closely packed particles: Use methods such as dip coating or precipitation to tightly pack the particles into the adhesive layer; and

[0186] S-a2 step: Substrate bi-stretching process: The coated substrate is placed in a film bi-stretching device. By controlling the stretching ratio and stretching speed in the XY direction (the ratio is 1 to 20 times and the stretching speed is 2 to 40 mm / min), stretching is carried out at a temperature of 40 to 60°C to achieve controllable arrangement of particles.

[0187] or

[0188] Step S-a1: Disperse the particles in solvent A, then add the solution-based adhesive, stir evenly, and coat it onto the surface of a stretchable substrate. Bake at 40–60°C for 30–120 min. The thickness of the resulting adhesive layer is 1 / 4 to 1 / 2 of the particle diameter, with an adhesive thickness tolerance of 0.05 μm.

[0189] S-a2 step: Perform biaxial stretching in the same manner as above.

[0190] <Second aspect>

[0191] This application provides a method for manufacturing an anisotropic functional adhesive film, the method comprising:

[0192] The particle arrangement method described in the first aspect above is used to arrange functional particles with functional conductivity to form a stretched composite structure.

[0193] Another adhesive layer is formed on the stretched composite structure.

[0194] In this context, the manufacturing method of the anisotropic functional film of this application can easily make the functional particles uniformly distributed and can adjust the distribution mode of the functional particles in the film as needed, without damaging the functional layer of the functional particles, with simple process and high yield, and is convenient for large-scale production.

[0195] Figure 3 An example of a method for manufacturing anisotropic functional adhesive films is shown. It is understood, of course, that the method for manufacturing anisotropic functional adhesive films of this application is not limited to... Figure 3 The example shown.

[0196] The following will explain each step in detail.

[0197] (Formation of the stretched composite structure (S-b1))

[0198] As described above, in addition to using functionally conductive particles as the particles to be arranged, the particle arrangement method described in the first aspect above is used to arrange the particles. Specifically, in this step, a composite structure comprising an adhesive layer (hereinafter sometimes referred to as adhesive layer A) and functional particles is formed on a stretchable substrate, with at least a portion of each functional particle embedded in adhesive layer A; the stretchable substrate carrying the composite structure is biaxially stretched such that the projections of each functional particle on at least one plane formed by the first and second directions of the substrate are separated from each other, thereby forming a stretched composite structure comprising adhesive layer A and arranged functional particles. Figure 3 As shown in the example, step S-b1 can be implemented through steps S-a1 and S-a2.

[0199] In step S-b1, in some preferred embodiments, in the stretched composite structure, multiple functional particles are preferably arranged in a matrix in a single layer at least on a plane formed by the first and second directions of the substrate. However, this does not mean that the actual center of each functional particle is in the same plane. There is a possibility that the actual center of more than one functional particle in the matrix is ​​not in the same plane as the actual center of other functional particles. However, the projections of each functional particle on the plane formed by the first and second directions of the substrate are separated from each other.

[0200] In step S-b1, the details of the method for forming the stretchable substrate and the stretched composite structure are the same as those in the particle arrangement method described in the first aspect above.

[0201] In step S-b1, there are no particular restrictions on the specific type of functional particles. Any functional particles with functional conductivity (e.g., electrical conductivity, magnetic conductivity, thermal conductivity, etc.) that are known in the art and can be used in anisotropic functional films are acceptable.

[0202] In some preferred embodiments, the functional particles are preferably the functional particles described in the following <Third Aspect> or <Fifth Aspect>, which will not be repeated here.

[0203] In this application, there is no particular limitation on the specific type of adhesive used in adhesive layer A; adhesives commonly used in the art to form anisotropic functional films can be used.

[0204] In some preferred embodiments, the adhesive used to form adhesive layer A is preferably thermosetting, examples of which include, but are not limited to, epoxy resin adhesives, (meth)acrylic resin adhesives, isocyanate adhesives, silicone adhesives, polyurethane adhesives, etc.

[0205] In some preferred embodiments, the adhesive resin contained in adhesive layer A is a thermosetting epoxy resin (i.e., the adhesive used in adhesive layer A is a thermosetting epoxy resin-based adhesive) or a thermosetting (meth)acrylic resin (i.e., the adhesive used in adhesive layer A is a (meth)acrylic resin-based adhesive). The details of these adhesives are the same as those in the particle arrangement method described in the first aspect above.

[0206] Without impairing the technical effects of this application, in addition to adhesives and functional particles, the adhesive layer A of the anisotropic functional adhesive film of this application may also contain other components as needed. Examples of these other components include, but are not limited to, inorganic particles and / or organic particles (optionally having electrical, thermal, or magnetic conductivity) other than the functional particles of this application, various tackifying resins, crosslinking accelerators, silane coupling agents, antioxidants, colorants (e.g., pigments or dyes), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, antistatic agents, fibers, etc. These other components may be used alone or in combination of two or more.

[0207] The amounts of these other components can be adjusted appropriately according to actual needs.

[0208] (Formation of another adhesive layer (S-b2))

[0209] As described above, another adhesive layer (hereinafter sometimes referred to as adhesive layer B) is formed on the stretched composite structure, such as Figure 3 The S-b2 step of the example is shown.

[0210] In step S-b2, there are no particular restrictions on the method of forming adhesive layer B. For example, adhesive layer B can be formed independently and then applied to the stretched composite structure; alternatively, a coating liquid for forming adhesive layer B can be applied to the stretched composite structure to form adhesive layer B.

[0211] In some preferred embodiments, adhesive layer B is preferably formed by applying an adhesive coating liquid onto a stretched composite structure and drying it to form adhesive layer B. In this case, there are no particular limitations on the coating method for the adhesive coating liquid, and the coating method includes, but is not limited to, brush coating, dip coating, spin coating, rod coating, doctor blade coating, curtain coating, screen printing coating, spray coating, slot coating, etc. These coating methods can be used alone or in combination of two or more.

[0212] In step S-b2, the composition of adhesive layer B may be the same as that of adhesive layer A, or it may be different. In some preferred embodiments, from the viewpoint of further improving the adhesion of the anisotropic functional adhesive film of this application and ensuring stability, the composition of adhesive layer B is the same as that of adhesive layer A.

[0213] In some preferred embodiments, from the viewpoint that the adhesiveness and mechanical properties of the anisotropic functional adhesive film of this application can be further improved, such as... Figure 3 As shown, adhesive layer B is fused with adhesive layer A to form a structure that encapsulates functional particles.

[0214] In this application, when at least one of the adhesive layers A and B contains a thermosetting adhesive, the thermosetting adhesive in the anisotropic functional adhesive film obtained in this step is preferably uncured and can be cured as needed before or during the use of the adhesive film.

[0215] Furthermore, in some preferred embodiments, in the anisotropic functional film of this application, the distance between the projections of the functional particles onto a plane formed by the first direction and the second direction is preferably greater than 0 μm and less than 25 μm, more preferably 1 μm to 15 μm, and even more preferably 2 μm to 10 μm.

[0216] In some preferred embodiments, after forming the adhesive layer B, the thickness of the resulting anisotropic functional film is preferably 10–50 μm. Furthermore, in some preferred embodiments, after forming the adhesive layer B, the thickness of the resulting anisotropic functional film is preferably 3–15 times the average particle size of the functional particles.

[0217] In some preferred embodiments, after forming the adhesive layer B, the total mass of the functional particles in the resulting anisotropic functional film is preferably 1 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 8% by mass, relative to the total mass of the adhesives (all the adhesives used in adhesive layer A and adhesive layer B).

[0218] (Other steps)

[0219] Without impairing the technical effect of this application, the manufacturing method of the anisotropic functional adhesive film of this application may also include other steps.

[0220] In some specific embodiments, a peelable protective film is applied to at least one of the adhesive film surfaces exposed to air before and / or after the formation of adhesive layer B.

[0221] <Third aspect>

[0222] This application provides a functional particle, wherein the functional particle comprises a core material and a metal layer covering the core material; the core material is formed of a polymer comprising units based on mono(meth)acrylate monomers with epoxy groups and units based on monomers with two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

[0223] In this context, the polymer core of the functional particles of this application contains two specific structural units, resulting in a flexible and tunable molecular chain structure. Furthermore, based on the active groups transformed from epoxy groups on their surface, they can chemically bond with the metal in the metal layer. Therefore, the functional particles can possess the desired morphology and hardness as needed, and the metal layer is not easily detached, ensuring high reliability. Simultaneously, the manufacturing method of these functional particles is stable and simple, resulting in uniform particle size. Therefore, the functional particles of this application are suitable for inclusion in anisotropic functional films, enabling the anisotropic functional films to possess excellent conductivity, precision, and functional stability, and to be suitable for various application scenarios.

[0224] In this application, the functional particles are preferably spherical or near-spherical particles. There is no particular limitation on the average particle size of the functional particles, which can be appropriately adjusted according to their specific application. In some preferred embodiments, from the viewpoint of being more suitable as functional particles for use in anisotropic functional films, the average particle size of the functional particles is preferably 1–15 μm, more preferably 1–10 μm, and even more preferably 3–10 μm. Furthermore, in other preferred embodiments, from the viewpoint of being more suitable as functional particles for use in anisotropic functional films, the particle size distribution of the functional particles is preferably + / -1.5 μm, more preferably + / -1 μm, and even more preferably + / -0.5 μm. Here, "+ / -X μm" means the range of (RX) μm to (R+X) μm, where R is the average particle size of the functional particles.

[0225] Here, "average particle size" and "particle size distribution" are measured by means known in the art, such as by commercial particle size analyzers or scanning electron microscopes.

[0226] In this application, there are no particular limitations on the surface morphology of the functional particles, which can be appropriately adjusted according to actual needs. In some preferred embodiments, the functional particles have a rough surface.

[0227] In this application, a "rough surface" means that, relative to an absolutely smooth curved surface, the surface of the functional particles has upward protrusions or downward depressions (having an uneven structure). In this application, there are no particular limitations on the specific structure of the rough surface of the functional particles; for example, the rough surface can be an irregular uneven structure or a regular uneven structure. Furthermore, the surface structure can be determined by the morphology of the polymer core material itself or obtained through other treatments. In some preferred embodiments, from the viewpoint of cost reduction, the rough surface structure of the functional particles in this application is determined by the morphology of the polymer core material itself.

[0228] In some preferred embodiments, from the viewpoint of enabling the functional particles to have a more suitable surface morphology and provide better conductivity when used in anisotropic functional films, the rough surface of the functional particles preferably has a rough structure formed by multiple burr structures, more preferably, the entire rough surface of the functional particles is a rough structure formed by multiple burr structures. Here, the so-called "burr structure" means a structure with a gradually decreasing cross-sectional area parallel to a true sphere surface with a radius equal to the minimum radius of the particle (the minimum distance between the particle surface and the particle center), protruding in a direction away from the center of the particle.

[0229] The polymer core and metal layer of the functional particles of this application will be described in detail below.

[0230] (core material)

[0231] As described above, the core material contained in the functional particles of this application is formed of a polymer, which comprises units based on mono(meth)acrylate monomers with epoxy groups and units based on monomers with two or more vinyl groups.

[0232] In this application, the unit based on the epoxy group of the mono(meth)acrylate monomer (hereinafter sometimes referred to as structural unit A) is a structural unit derived from the epoxy group of the mono(meth)acrylate monomer.

[0233] In this application, there is no particular limitation on the specific types of epoxy-containing mono(meth)acrylate monomers, which can be appropriately selected according to actual needs. In some preferred embodiments, the epoxy-containing mono(meth)acrylate monomers are preferably represented by the following formula A.

[0234]

[0235] In this configuration, R1 is a methyl or hydrogen atom, R2 is an aliphatic alkylene group with 1 to 12 carbon atoms, an aliphatic oxane alkylene group with 1 to 12 carbon atoms, or an alicyclic alkylene group with 3 to 12 carbon atoms, and Q is an epoxy group with 3 to 6 constituent atoms. Q and R2 can be connected by a single bond, or a fused ring structure can be formed when R2 is an alicyclic alkylene group.

[0236] In some preferred embodiments, from the viewpoint of a balance between cost and adjustable structure, the epoxy-containing mono(meth)acrylate monomer is more preferably glycidyl methacrylate or 2,3-epoxycyclohexylmeth(meth)acrylate, and even more preferably glycidyl methacrylate.

[0237] In this application, the unit based on a monomer with two or more vinyl groups (hereinafter sometimes referred to as structural unit B) is a structural unit derived from a monomer with two or more vinyl groups.

[0238] In this application, there is no particular limitation on the specific types of monomers having two or more vinyl groups, and they can be appropriately selected according to actual needs. In some preferred embodiments, the monomers having two or more vinyl groups are at least one selected from polyvalent (meth)acrylate monomers having two or more (meth)acrylate groups, polyvalent vinyl ester monomers having two or more vinyl groups, polyvalent vinyl ether monomers having two or more vinyl groups, and polyvalent olefin monomers having two or more vinyl groups.

[0239] Examples of the aforementioned polyvalent (meth)acrylate monomers include, but are not limited to, tricyclodecanediethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol penta(meth)acrylate, pentaerythritol hexa(meth)acrylate, dimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate, etc.

[0240] Examples of the aforementioned polyvalent vinyl ester monomers include, but are not limited to, divinyl oxalate, divinyl malonate, divinyl succinate, divinyl glutarate, divinyl adipate, divinyl heptaate, divinyl octanoate, divinyl azelate, divinyl sebacate, divinyl dodecanoate, and trivinyl benzoate.

[0241] Examples of the aforementioned polyvalent vinyl ether monomers include, but are not limited to, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, tripropylene glycol divinyl ether, 1,4-butanediol divinyl ether, and neopentyl glycol divinyl ether.

[0242] Examples of the aforementioned polyvalent olefin monomers include, but are not limited to, divinylbenzene, trivinylbenzene, etc.

[0243] In some preferred embodiments, the monomer having two or more vinyl groups is at least one selected from polyvalent (meth)acrylate monomers having two or more (meth)acrylate groups, polyvalent vinyl ester monomers having two or more vinyl groups, and polyvalent olefin monomers having two or more vinyl groups.

[0244] Without impairing the technical effects of this application, in addition to the structural units A and B described above, the polymer may also contain units based on other comonomers (hereinafter sometimes also referred to as structural unit C). Generally, there are no particular restrictions on the specific types of other comonomers, as long as they can be polymerized with the aforementioned epoxy-containing mono(meth)acrylate monomers and the aforementioned monomers containing two or more vinyl groups.

[0245] Examples of such other comonomers typically include, but are not limited to: monoolefin monomers such as ethylene, propylene, butene, styrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, benzylchlorostyrene, and 4-tert-butylstyrene; conjugated diene monomers such as butadiene and isoprene; mono(meth)acrylate monomers without epoxy groups such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, cyclohexyl (meth)acrylate, and n-hexyl (meth)acrylate; nitrile monomers such as acrylonitrile; and (meth)acrylamide monomers such as N-phenylacrylamide, N-phenylmethylacrylamide, N-benzylacrylamide, N-(4-chlorophenyl)acrylamide, N-tert-butylacrylamide, N-dodecylacrylamide, N-octadecylacrylamide, N,N-diethylacrylamide, and N,N-dibutylacrylamide. These other comonomers can be used alone or in combination of two or more.

[0246] In this application, there are no particular restrictions on the respective content ratios of the above-mentioned structural unit A, structural unit B, and structural unit C, which can be appropriately adjusted according to actual needs.

[0247] In some preferred embodiments, from the viewpoint that the functional particles can have a more suitable morphology and / or hardness, and can provide stronger adhesion and greater reliability to the metal layer, the ratio of the above structural unit A relative to all structural units of the polymer is preferably 80-98% by mass, more preferably 90-98% by mass, and even more preferably 94-98% by mass.

[0248] In some preferred embodiments, from the viewpoint of giving the functional particles a more suitable degree of softness and hardness, the ratio of the above-mentioned structural unit B to all structural units of the polymer is preferably 2 to 20% by mass, more preferably 2 to 10% by mass, and even more preferably 2 to 6% by mass.

[0249] In some preferred embodiments, the mass ratio of the above-mentioned structural unit A to the above-mentioned structural unit B is preferably 80 / 20 to 98 / 2.

[0250] In some preferred embodiments, the ratio of the above-mentioned structural unit C relative to all structural units of the polymer is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0251] In some preferred embodiments, the K30% hardness of the core material is preferably 500–2500 N / mm². 2 More preferably 1000–1500 N / mm 2The K30% hardness was measured using a micro-compression tester (MCT, manufactured by Shimadzu).

[0252] In some preferred embodiments, the degree of crosslinking of the polymer is preferably 0.5% to 20%, more preferably 1% to 10%.

[0253] (Metal layer)

[0254] As described above, the functional particles of this application have a metal layer coated on a polymer core material and are chemically bonded to the polymer. In some preferred embodiments, the surface morphology formed by the metal layer depends on the surface morphology of the polymer core material.

[0255] In this application, there are no particular restrictions on the specific composition of the metal layer, which can be appropriately selected according to actual needs (such as the function to be conducted). In this application, the metal layer may contain a single metal or two or more metals.

[0256] In some preferred embodiments, from the viewpoint that functional particles can provide superior conductivity and functional stability when used in anisotropic functional films, the metal layer is a layer including gold, silver, copper, nickel, palladium, platinum, or any combination thereof.

[0257] (Other components)

[0258] In addition to the polymer core and metal layer mentioned above, the functional particles of this application may also include other components to make the functional particles of this application suitable for various application scenarios and / or endowed with other functions.

[0259] In some specific embodiments, magnetic particles may be embedded in the polymer core of the functional particles of this application.

[0260] In some specific embodiments, the functional particles of this application may have an inorganic particle layer formed of non-conductive inorganic particles, an organic layer formed of resin and / or elastomer, a metal plating layer other than the metal layer of this application, etc., outside the metal layer.

[0261] <Fourth Aspect>

[0262] This application also provides a method for manufacturing the above-mentioned functional particles in the <Third Aspect> of this application, the method comprising: adding at least an epoxy-containing mono(meth)acrylate monomer and a monomer containing two or more vinyl groups to a dispersion medium containing a surfactant for polymerization to form initial polymer particles; using an activator to activate the epoxy groups on the surface of the initial polymer particles to form activated polymer particles; adding the activated polymer particles to an aqueous solution of a metal compound and using a reducing agent to form a metal layer on its surface.

[0263] The manufacturing method of this application enables the polymerization of epoxy-containing mono(meth)acrylate monomers and monomers containing two or more vinyl groups in various proportions to obtain initial polymer particles with high size uniformity, and to achieve chemical bonding between the metal layer and the polymer core material formed from the initial polymer particles. This allows for the easy production of functional particles with highly adjustable morphology and hardness, high metal layer reliability, and uniform size. Furthermore, the manufacturing method of this application is environmentally friendly, has a simple process, and is suitable for large-scale production.

[0264] Figure 4 The illustration shows a specific example of the manufacturing method of the functional particles of this application (using GMA and EDGMA as monomers to form polymer particles, gold as the metal, thiol groups as the active groups, and sodium borohydride NaBH4 as the reducing agent). Of course, it is understood that the manufacturing method of the functional particles of this application is not limited to... Figure 4 The example shown.

[0265] The following will describe each step in detail.

[0266] (Preparation of initial polymer particles (S-c1))

[0267] As described above, at least a mono(meth)acrylate monomer with an epoxy group and a monomer with two or more vinyl groups are added to a dispersion medium containing a surfactant for polymerization to form initial polymer particles, such as... Figure 4 The steps in the example are as shown in S-c1. Figure 5 An example of initial polymer particles is shown (using emulsion polymerization of GMA and EDGMA at 75°C).

[0268] Here, details of the epoxy-containing mono(meth)acrylate monomers, monomers with two or more vinyl groups, and optional other comonomers participating in the polymerization have been described in the above "<First Aspect>" and will not be repeated here.

[0269] In step S-c1, there are no particular restrictions on the polymerization method used, as long as initial polymer particles can be obtained. Examples of such polymerization methods include, but are not limited to, emulsion polymerization, dispersion polymerization, precipitation polymerization, seed swelling polymerization, suspension polymerization, and SPG film emulsification.

[0270] Dispersion polymerization includes two stages: polymerization nucleation and polymer particle growth. It can prepare particles ranging from nanometer to micrometer in size, with a uniform and adjustable particle size distribution (more uniform than emulsion polymerization). The dispersion medium can be a low-toxicity and low-hazard medium, reducing environmental pollution. It is one of the mainstream methods for particle preparation.

[0271] Emulsion polymerization includes four stages: initiation, nucleation of primary particles, coagulation into secondary particles, and growth into spheres. It has a fast reaction rate, high weight-average molecular weight of the product, uses water as a medium, has simple post-processing, is a green production method, and has a simple process, but the particle size distribution uniformity is poor.

[0272] Precipitation polymerization includes sedimentation nucleation and polymer particle growth stages. The polymer particles are uniform and clean, and the polymerization system has low viscosity. It does not require surfactants or stabilizers, but the particle yield is low and the solvent toxicity is high.

[0273] The seed swelling method first uses soap-free emulsion polymerization, dispersion polymerization, etc. to produce small-diameter monodisperse polymer particles, and then uses these as seeds to swell and grow the particles. It is a good method for synthesizing micron-sized particles and is also one of the mainstream commercial methods at present.

[0274] Suspension polymerization includes a liquid-liquid dispersion period, a particle growth period, and a particle stabilization period. It involves turbulent stirring of monomers under the action of a dispersant to form a dynamic equilibrium of dispersion and aggregation in water. It can be used to prepare particles with a diameter of 5–1000 μm, but the particle size tends to exhibit polydispersity.

[0275] SPG membrane emulsification involves mixing two immiscible liquids in the presence of an appropriate amount of surfactant to create an emulsion. The hydrophobic monomer is then forced through the micropores of the SPG membrane under N2 pressure to form tiny droplets, thus producing particles with uniform particle size. This method can be used to prepare monodisperse polymer particles ranging from 10 to 1000 μm, but it has low yield and high cost.

[0276] In some preferred embodiments of this application, emulsion polymerization is used for polymerization. In some more preferred embodiments, the various monomers to be polymerized are dispersed in a dispersion medium and polymerized into particles in the presence of a surfactant and under the action of an initiator.

[0277] The dispersion medium is preferably an aqueous medium, and examples include, but are not limited to, ethanol, methanol, n-propanol, isopropanol, n-butanol, ethylene glycol, propylene glycol, diethylene glycol, pyrrolidone, and water. These dispersion media can be used alone or in combination of two or more.

[0278] Surfactants can generally be classified into emulsifiers and stabilizers as known in the art. Emulsifiers or stabilizers can be used alone or in combination as surfactants. In this step, there are no particular restrictions on the specific types of emulsifiers and stabilizers used; they can be appropriately selected based on the type and proportion of monomers to be polymerized, the composition of the dispersion medium, and the desired morphology of the polymer core material.

[0279] Examples of emulsifiers typically include, but are not limited to, nonionic emulsifiers such as polyoxyethylene ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene styrene phenyl ethers, polyoxyethylene benzyl phenyl ethers, polyoxyethylene isopropylphenyl phenyl ethers, fatty acid polyethylene glycol ethers, and dehydrated sorbitol fatty acid esters; anionic emulsifiers such as fatty acid soaps, rosin acid soaps, alkyl sulfonates, alkyl aryl sulfonates, alkyl sulfates, alkyl sulfosuccinates, and sulfates, phosphates, ether carboxylates, and sulfosuccinates of nonionic emulsifiers having polyoxyethylene chains; and cationic emulsifiers such as stearyltrimethylammonium salt, cetyltrimethylammonium salt, lauryltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, and alkyldimethylhydroxyethylammonium salt. In some preferred embodiments, the emulsifier is preferably selected from at least one of sodium dodecylbenzenesulfonate, dodecylbenzene ammonium chloride, polyoxyethylene ether, and sodium dodecylbenzenesulfonate.

[0280] Examples of stabilizers typically include, but are not limited to, natural polymeric stabilizers such as gelatin, agar, pectin, and alginate; cellulose-based stabilizers such as methylcellulose, ethylcellulose, carboxycellulose, hydroxymethylcellulose, and hydroxypropylcellulose; and synthetic polymeric stabilizers such as polyvinyl alcohol, poly(meth)acrylate, polyethylene glycol, polypropylene glycol, and polyvinylpyrrolidone. In some preferred embodiments, the stabilizer is preferably at least one selected from polyvinylpyrrolidone, polyethylene glycol, and polyvinyl alcohol.

[0281] In step S-c1, in some preferred embodiments, the surfactant is preferably a combination of an emulsifier and a stabilizer.

[0282] There are no particular restrictions on the specific type of initiator. In some preferred embodiments, the initiator is preferably an initiator for free radical polymerization. Examples of initiators include, but are not limited to, azo initiators, such as azobisisobutyronitrile, azobisisovalerate, and azobisisoheptanenitrile; and organic peroxide initiators, such as tert-butyl peroxynivalenate, tert-butyl peroxynivalenate, disec-butyl peroxydicarbonate, bis(hexadecyl)dicarbonate peroxide, tert-pentyl peroxynivalenate, tert-butyl peroxynivalenate, di-(4-tert-butylcyclohexyl peroxydicarbonate), dicyclohexyl peroxydicarbonate, diisopropyl peroxydicarbonate, and dibutyl peroxydicarbonate. The initiator comprises: di(2-ethylhexyl) peroxide dicarbonate, tert-butyl peroxide 2-ethylhexanoate, ditetradecyl peroxide dicarbonate, tert-butyl peroxide acetate, cumyl peroxide neodecanoate, ditert-butyl peroxide, cyclohexylsulfonyl peroxide, benzoyl peroxide, diisobutyryl peroxide, 1,1,3,3-tetramethylbutyl peroxide neodecanoate, di-3-methoxybutyl peroxide dicarbonate, and 1,1,3,3-tetramethylbutyl peroxide pentanoate; persulfate initiators, such as ammonium persulfate and potassium persulfate. In some preferred embodiments, the initiator is preferably at least one selected from ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisoheptanenitrile.

[0283] In step S-c1, there are no particular restrictions on the proportions of the components. In some preferred embodiments, the surface morphology of the initial polymer particles can be adjusted by modifying the proportions of the emulsifier, stabilizer, initiator, epoxy-based mono(meth)acrylate monomers, monomers with two or more vinyl groups, and the dispersion medium.

[0284] In some more preferred embodiments, the mass ratio of emulsifier, stabilizer, initiator, epoxy-containing mono(meth)acrylate monomer, monomer with two or more vinyl groups, and dispersion medium (emulsifier: stabilizer: initiator: epoxy-containing mono(meth)acrylate monomer: monomer with two or more vinyl groups: dispersion medium) is preferably 1:0.05-5:0.05-5:25-200:1-50:50-500, more preferably 1:1-3:0.1-3:50-150:5-30:100-300, and even more preferably 1:1-2:0.1-1:50-100:10-20:100-200.

[0285] In step S-c1, there are no particular restrictions on the polymerization atmosphere. In some preferred embodiments, polymerization is carried out in an inert gas atmosphere such as nitrogen or helium.

[0286] In the S-c1 step, there are no special restrictions on the polymerization conditions, which can be appropriately selected according to the type of monomer used.

[0287] In some preferred embodiments, the polymerization temperature is preferably 50–120°C, and more preferably 60–100°C.

[0288] In some preferred embodiments, the polymerization time is preferably 0.5 to 6 hours.

[0289] In some preferred embodiments, polymerization is carried out under dynamic action. Examples of dynamic action here include, but are not limited to, ultrasound, stirring, oscillation, etc.

[0290] In the S-c1 step, there are no particular restrictions on how monomers are added. They can be added together, in batches in any combination, or continuously dropwise in any combination.

[0291] After polymerization, the initial polymer particles of this application may be separated (e.g., centrifuged or filtered), washed (e.g., soaked or rinsed), or dried (e.g., oven dried) as needed by methods commonly used in the art.

[0292] (Activation of initial polymer particles (S-c2))

[0293] As described above, an activator is used to activate the epoxy groups on the surface of the initial polymer particles to form activated polymer particles, such as... Figure 4 The steps in the example are as shown in step S-c2.

[0294] In step S-c2, there are no particular restrictions on the contact method between the activator and the initial polymer particles. In some preferred embodiments, the initial polymer particles are dispersed in a dispersion medium, and then the activator is added and the reaction is carried out.

[0295] Examples of dispersion media described above in "(Preparation of Initial Polymer Particles)" will not be repeated here. The dispersion media used in this step may be the same as or different from those used in the polymerization of the initial polymer particles. In some preferred embodiments, from the viewpoint of reaction convenience, the dispersion media used in this step is preferably water.

[0296] In step S-c2, there are no particular limitations on the active groups formed on the surface of the initial polymer particles, as long as they can be grafted with metal during the subsequent formation of the metal layer. In some preferred embodiments, the active groups are preferably hydroxyl, amino, carboxyl, or thiol groups, more preferably carboxyl or thiol groups, and even more preferably thiol groups.

[0297] There are no particular restrictions on the specific type of activator used, and it can be appropriately selected according to the type of active groups desired. Examples of activators include, but are not limited to, ozone (O3); weak acids such as hydrogen sulfide (H2S), acetic acid, oxalic acid, and hypochlorous acid; and strong acids such as sulfuric acid, nitric acid, and hydrochloric acid. In some preferred embodiments, from the viewpoint of more effectively activating the initial polymer particles, the activator is preferably selected from ozone (O3), hydrogen sulfide (H2S), acetic acid, oxalic acid, sulfuric acid, nitric acid, etc.

[0298] In addition, in some preferred embodiments, the mass ratio of the activator to the initial polymer particles is preferably 1:50 to 1:200, more preferably 1:50 to 1:150, and even more preferably 1:50 to 1:100.

[0299] In the S-c2 step, there are no particular restrictions on the activation reaction conditions, which can be appropriately selected according to the activator used.

[0300] In some preferred embodiments, the reaction temperature is preferably 40–60°C.

[0301] In some preferred embodiments, the reaction time is preferably 0.1 to 3 hours, more preferably 0.5 to 2 hours.

[0302] In some preferred embodiments, the activation reaction is carried out under dynamic conditions. Examples of dynamic conditions include, but are not limited to, ultrasound, stirring, and oscillation.

[0303] After the reaction is complete, the activated polymer particles of this application may be separated (e.g., centrifuged or filtered), washed (e.g., soaked or rinsed), or dried (e.g., oven dried) by means commonly used in the art, as needed.

[0304] (Construction of the metal layer (S-c3))

[0305] As described above, the obtained activated polymer particles are added to an aqueous solution of a metal compound, and a reducing agent is used to form a metal layer on its surface. Specifically, the activated groups on the surface of the activated polymer particles can react with the metal ions reduced by the reducing agent in the aqueous solution of the metal compound to prepare a robust metal layer. Figure 4 The steps in the example are as shown in S-c3.

[0306] Figure 6 An example of constructing a metal layer on activated polymer particles is shown (the metal is gold, the activated group is thiol, and the reducing agent is sodium borohydride NaBH4).

[0307] In this step, there are no particular restrictions on the metal compound used, and it can be appropriately selected according to the type of metal layer to be formed and the type of active groups. In some preferred embodiments, from the viewpoint of more effectively forming a metal layer, the metal compound is preferably at least one selected from chloroauric acid tetrahydrate, silver nitrate, silver chloride, copper nitrate, copper sulfate, nickel sulfate, palladium chloride, palladium nitrate, and chloroplatinic acid.

[0308] In step S-c3, the reducing agent can be one commonly used in the field, such as sodium borohydride, hydrazine hydrate, etc.

[0309] In the S-c3 step, there are no particular restrictions on the amount of metal compound and reducing agent used, and they can be adjusted appropriately according to the type of active group, the type of metal compound, and the type of reducing agent.

[0310] In addition, there are no particular restrictions on the reaction conditions for the metal layer formation reaction in the S-c3 step, and they can be appropriately selected according to the type of active group, the type of metal compound, the type of reducing agent, etc.

[0311] In some preferred embodiments, the reaction temperature is preferably 40–60°C.

[0312] In some preferred embodiments, the reaction time is preferably 0.1 to 3 hours, more preferably 0.5 to 2 hours.

[0313] In some preferred embodiments, the activation reaction is carried out under dynamic conditions. Examples of dynamic conditions include, but are not limited to, ultrasound, stirring, and oscillation.

[0314] After the reaction is complete, the functional particles of this application may be separated (e.g., centrifuged or filtered), washed (e.g., soaked or rinsed), or dried (e.g., oven dried) as needed by methods commonly used in the art.

[0315] (Other steps)

[0316] In addition to the steps described above, the method for manufacturing the functional particles of this application may also include other steps depending on the composition of the final functional particles.

[0317] In some specific embodiments, the deposition steps of non-conductive inorganic particles, the coating steps of resin and / or elastomers, the metal plating steps, etc.

[0318] (Specific examples)

[0319] In some particularly preferred embodiments, the functional particles of this application are obtained by the following methods:

[0320] Emulsifier, stabilizer, and dispersion medium are added to a reaction vessel and stirred thoroughly. Nitrogen gas is then introduced, and the temperature is raised to 60°C. A mixture of initiator, epoxy-containing mono(meth)acrylate monomers, monomers with two or more vinyl groups, and dispersion medium is then added to the reaction solution. After the addition is complete, the reaction continues for 1 hour. Finally, by centrifugation and washing, initial polymer particles with epoxy groups on their surface are obtained.

[0321] The initial polymer particles are added to water, and then an activator is added. The mass ratio of the activator to the polymer particles is 1:50 to 200. The reaction is carried out at a temperature of 40 to 60°C and stirred for 30 to 120 minutes. After centrifugation and washing, polymer particles with carboxyl or thiol groups on the surface can be obtained.

[0322] The activated polymer particles with a large number of active functional groups on their surface are added to an aqueous solution of a metal compound, and then a reducing agent is added. The mixture is stirred at 40–60°C for 30–120 minutes to obtain functional particles with a metal layer on their surface.

[0323] <Fifth Aspect>

[0324] This application provides a functional particle obtained by a manufacturing method comprising: polymerizing at least an epoxy-containing mono(meth)acrylate monomer and a monomer containing two or more vinyl groups in a dispersion medium containing a surfactant to form initial polymer particles (manufacturing of initial polymer particles (S-d1)); activating the epoxy groups on the surface of the initial polymer particles using an activator to form activated polymer particles (activation of initial polymer particles (S-d2)); adding the activated polymer particles to an aqueous solution of a metal compound and forming a metal layer on its surface using a reducing agent (construction of the metal layer (S-d3)).

[0325] In this context, the functional particles of this application are obtained through a specific method, enabling the polymerization of epoxy-based mono(meth)acrylate monomers and monomers with two or more vinyl groups in various proportions to form initial polymer particles and chemically bonding the metal layer to the polymer core material formed from the initial polymer particles. The polymer core material of these functional particles has a flexible and tunable molecular chain structure and strong adhesion to the metal layer. Therefore, the functional particles can have the desired morphology and hardness as needed, and the metal layer is not easily detached, resulting in high reliability. Simultaneously, the functional particles have uniform size. Therefore, these functional particles are particularly suitable for inclusion in anisotropic functional films, enabling the anisotropic functional films to possess excellent conductivity, precision, and functional stability, and to be suitable for various application scenarios.

[0326] In step S-d1 above, as described above, initial polymer particles are formed, thereby serving as the basis for the polymer core material of the functional particles.

[0327] In the S-d2 step described above, as mentioned above, the epoxy groups on the surface of the initial polymer particles are activated, and the activated groups on the resulting activated polymer particles are used to bind metals in later steps.

[0328] In the S-d3 step described above, as mentioned above, a metal layer is formed on the surface of the activated polymer particles using the activated groups on the activated polymer particles.

[0329] The details of steps S-d1, S-d2, and S-d3 above (including each preferred embodiment) are the same as those of steps S-c1, S-c2, and S-c3 in the method for manufacturing functional particles described in the fourth aspect above, and will not be repeated here.

[0330] In addition to the S-d1, S-d2, and S-d3 steps described above, the method for manufacturing functional particles in this aspect may include other steps depending on the composition of the final functional particles.

[0331] In some specific embodiments, the deposition steps of non-conductive inorganic particles, the coating steps of resin and / or elastomers, the metal plating steps, etc.

[0332] The functional particles of this aspect comprise a core material and a metal layer covering the core material. The core material is formed of a polymer comprising units based on mono(meth)acrylate monomers with epoxy groups and units based on monomers with two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer. Details of the functional particles of this aspect are the same as those described in the aforementioned <Third Aspect>, and will not be repeated here.

[0333] <Sixth Aspect>

[0334] This application also provides an anisotropic functional adhesive film, which is a film-like adhesive material comprising an adhesive and the aforementioned functional particles as described in the <Third Aspect> or <Fifth Aspect> of this application.

[0335] The anisotropic functional film of this application contains functional particles with highly adjustable morphology and hardness, high reliability of the metal layer, and uniform size. Regardless of the arrangement of these functional particles, it can also have excellent conductivity, precision, and functional stability, and is suitable for different application scenarios.

[0336] In this application, there are no particular restrictions on the arrangement of functional particles in the anisotropic functional film, and they can be appropriately selected according to actual needs.

[0337] In some specific embodiments, from the viewpoint that the anisotropic functional adhesive film of this application can be more easily formed, it is preferred that the functional particles are randomly dispersed in the adhesive. In this case, the anisotropic functional adhesive film of this application can be obtained by methods known in the art, for example, mixing the material used to form the adhesive with the functional particles, then coating it onto a substrate and drying it; however, it is understood that the formation method is not limited to this.

[0338] In other specific embodiments, from the viewpoint of better combining excellent conductivity, precision and functional stability, and being suitable for different application scenarios, the functional particles are distributed in a manner that separates them from each other at least in projections onto a plane formed by the first and second directions of the film.

[0339] Here, there are no particular limitations on the first direction, the second direction, or the angle between them. In some preferred embodiments, the first direction and the second direction are preferably perpendicular to each other. In other preferred embodiments, the plane formed by the first direction and the second direction is preferably parallel to the surface of the substrate. More preferably, the first direction is the transverse direction of the substrate, and the second direction is the longitudinal direction of the substrate.

[0340] In this case, the anisotropic functional film of this application can be obtained by methods known in the art. In some preferred embodiments, the distance between the projections of the functional particles onto a plane formed by the first and second directions is preferably greater than 0 μm and less than 25 μm, more preferably 0 μm to 9 μm, and even more preferably 2 μm to 6 μm.

[0341] Furthermore, in some other preferred embodiments, the anisotropic functional adhesive film of this application can be obtained by the method described in the above-mentioned <Second Aspect>. In this case, for convenience, the term "Z direction" refers to the direction perpendicular to the surface of the adhesive film or the substrate supporting the adhesive film (i.e., the thickness direction), the term "X direction" refers to the direction corresponding to the transverse direction (sometimes also called the width direction, i.e., the TD direction) of the substrate supporting the adhesive film, the term "Y direction" refers to the direction corresponding to the longitudinal direction (sometimes also called the mechanical direction, i.e., the MD direction) of the substrate supporting the adhesive film, and the so-called "XY direction" refers to the direction parallel to the surface of the adhesive film or the substrate supporting the adhesive film (i.e., the planar direction), wherein the so-called "surface of the adhesive film" can generally be understood as the surface that contacts the substrate supporting the adhesive film during the manufacturing process of the adhesive film.

[0342] In some preferred embodiments of this application, the thickness of the anisotropic functional film is preferably 10–50 μm. Furthermore, in some preferred embodiments, from the viewpoint that the anisotropic functional film better ensures excellent conductivity, precision, and functional stability, the thickness of the anisotropic functional film is preferably 3–15 times the average particle size of the functional particles.

[0343] In some preferred embodiments of this application, the total mass of the functional particles is preferably 1 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 8% by mass, relative to the total mass of the adhesive in the film.

[0344] In this application, there are no particular restrictions on the presentation of the anisotropic functional film. It can be in the form of a film without a substrate or in the form of a film carried on a substrate (e.g., a substrate used to carry the film during the manufacturing process).

[0345] The components will be described in detail below.

[0346] (Functional particles)

[0347] Details of the functional particles in this application have been described in the above “Third Aspect” or “Fifth Aspect”, and will not be repeated here.

[0348] (Adhesive)

[0349] In this application, there is no particular limitation on the specific type of adhesive, and various adhesives commonly used in the art to form anisotropic functional films can be used.

[0350] In some preferred embodiments of this application, the adhesive is preferably thermosetting, examples of which include, but are not limited to, epoxy resin adhesives, (meth)acrylic resin adhesives, isocyanate adhesives, silicone adhesives, polyurethane adhesives, etc.

[0351] In this application, when the adhesive in the anisotropic functional adhesive film contains a thermosetting adhesive, the thermosetting adhesive is preferably uncured and can be cured as needed before or during the use of the adhesive film.

[0352] In some preferred embodiments, the adhesive resin contained in the adhesive is a thermosetting epoxy resin (i.e., the adhesive used in adhesive layer A is a thermosetting epoxy resin-based adhesive) or a thermosetting (meth)acrylic resin (i.e., the adhesive used in adhesive layer A is a thermosetting (meth)acrylic resin-based adhesive). The details of these adhesives are the same as those in the particle arrangement method described in the first aspect above.

[0353] (Other components)

[0354] Without impairing the technical effects of this application, in addition to adhesives and functional particles, the anisotropic functional adhesive film of this application may also contain other components as needed. Examples of such other components include, but are not limited to, inorganic and / or organic particles (optionally having electrical, thermal, or magnetic conductivity) other than the functional particles of this application, various tackifying resins, crosslinking accelerators, silane coupling agents, antioxidants, colorants (e.g., pigments or dyes), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, antistatic agents, fibers, etc. These other components may be used alone or in combination of two or more.

[0355] The amounts of these other components can be adjusted appropriately according to actual needs.

[0356] (Application Scenarios)

[0357] In this application, the anisotropic functional adhesive film has a wide range of applications and can impart anisotropic properties to many devices. For example, as anisotropic conductive adhesive, it can be used for electrical interconnection between ICs, FPCs / COFs and display devices in end products; as anisotropic magnetic adhesive, it can be used for signal transmission and prevent signal crosstalk; as anisotropic thermal adhesive, it can form a good heat dissipation effect on chips or device modules.

[0358] Taking anisotropic conductive adhesive as an example, its system architecture and scenarios are described below, serving as a specific example in... Figure 7 As shown in the image.

[0359] Anisotropic conductive adhesive is applied to the conductive bumps on the substrate. After aligning and attaching other components, the adhesive film softens (becoming a gel) when pressure and heat are applied. The conductive particles then flow and distribute evenly, ensuring a certain number of conductive particles in each line and guaranteeing a stable resistance value. Under bonding pressure, the insulating film of the conductive particles ruptures, trapping multiple deformed conductive particles between the bumps on the disc and the corresponding ITO circuits on the glass substrate. These deformed conductive particles achieve electrical interconnection between the upper and lower bumps. Particles in other unpressurized areas do not contact each other, thus achieving anisotropic interconnection with insulation in the XY direction and anisotropic interconnection in the Z direction.

[0360] <Example>

[0361] The embodiments of this application are described in detail below, but this application is not limited to the embodiments described below.

[0362] Example 1: Preparation of an anisotropic conductive film

[0363] (1) Preparation of conductive particles

[0364] Preparation of (S-c1) initial polymer particles:

[0365] Emulsifier, stabilizer, and dispersion medium are added to the reaction vessel and stirred thoroughly. Nitrogen gas is then introduced, and the temperature is raised to 60°C. A mixture of initiator, glycidyl methacrylate, trimethylolpropane tetraacrylate, and dispersion medium is then added to the reaction solution. After the addition is complete, the reaction continues for 1 hour. The resulting initial polymer particles with epoxy groups on their surface are obtained by centrifugation and washing.

[0366] The emulsifier is sodium dodecylbenzenesulfonate, the stabilizer is polyvinylpyrrolidone, the dispersion medium is ethanol, and the initiator is ammonium persulfate. The mass ratio of sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, ammonium persulfate, glycidyl methacrylate, dimethylolpropane tetraacrylate, and ethanol is 1:1:0.1:50:10:100.

[0367] Activation of (S-c2) initial polymer particles:

[0368] The initial polymer particles were added to water, and then an activator was added. The mass ratio of the activator to the initial polymer particles was 1:50. The reaction was carried out at a reaction temperature of 40°C and stirred for 30 minutes. After centrifugation and washing, activated polymer particles with carboxyl groups on the surface were obtained. The activator was O3.

[0369] (S-c3) Constructing a metal layer on the surface of activated polymer particles:

[0370] The surface-activated polymer particles were dispersed in water, sodium borohydride was added, and then chloroauric acid tetrahydrate solution was added dropwise. The reaction was carried out with stirring for 30 minutes. The mass ratio of polymer particles, water, sodium borohydride and chloroauric acid tetrahydrate was 1:50:0.2:0.1. This yielded functional particles with gold grafted on the surface, which were then washed by centrifugation.

[0371] The reaction involved is: 8HAuCl4·4H2O + 3NaBH4 → 8Au + 3H3BO3 + 29HCl + 3NaCl + 23H2O

[0372] In this mixture, HAuCl4·4H2O is chloroauric acid tetrahydrate, NaBH4 is sodium borohydride, Au is gold particles, and H3BO3 is boric acid.

[0373] (2) Preparation of solvent-based epoxy resin adhesive coating solution:

[0374] Solid epoxy resin, liquid epoxy resin, latent curing agent, toughening agent, and solvent are mixed in a weight ratio of 1:1:0.05:0.1:3 and stirred evenly to obtain a solvent-based epoxy resin adhesive coating liquid.

[0375] The solid epoxy resin is a solid phenolic epoxy resin with a weight average molecular weight of about 12,000, the liquid epoxy resin is bisphenol A epoxy resin, the latent curing agent is dimethylimidazole, the toughening agent is a core-shell polymer plasticizer, and the solvent is dichloromethane.

[0376] (3) Preparation of anisotropic conductive adhesive film:

[0377] Arrangement of (S-b1) functional particles

[0378] Functional particles are dispersed in tetrahydrofuran, and then the above-mentioned solvent-based epoxy resin adhesive coating solution is added. After stirring evenly, the mixture is coated onto a PET film (the mass ratio of polymer particles, tetrahydrofuran, and epoxy resin in the solvent-based epoxy resin adhesive coating solution is 1:5:1). After baking at 40°C and solvent drying, the film stretching stage begins. The stretching ratio in the X direction is 1, the stretching ratio in the Y direction is 1, and an angle stretching of 10° is performed in both the X and Y directions (e.g., ...). Figure 3 As shown, the stretching is performed symmetrically at 10° relative to the X direction (hereinafter the same). The anisotropic conductive adhesive is controllably adjusted so that the final projected distance between particles in the XY direction is 1 μm.

[0379] In the substrate after biaxial stretching, the orientation degree in the X direction is 1.8, the orientation degree in the Y direction is 3.0, the ratio of the orientation degree in the X direction to the orientation degree in the Y direction is 1.7, and the orientation angle relative to the X direction is 45°.

[0380] Here, the degree of orientation and the orientation angle are measured as described above.

[0381] Formation of (S-b2) anisotropic conductive film

[0382] A layer of the solvent-based epoxy resin adhesive coating liquid is then coated on the pre-arranged functional particle initial adhesive film prepared in step (S-b1). After baking at 40°C and drying the solvent, the coating liquid is fused with the initial adhesive film prepared in step (S-b1) to obtain an anisotropic conductive adhesive film with a total thickness of 10 μm.

[0383] An anisotropic conductive film measuring 2mm × 19mm was bonded to a glass substrate containing an IZO circuit at 80℃ and 0.98MPa. The separator was then peeled off, and the chip bumps were positioned on the glass substrate with the IZO circuit. The chip was then heated or hot-pressed from above at 160℃ for final connection, followed by electrical performance testing. The results showed that the average on-resistance was less than 2Ω, and the insulation resistance was greater than or equal to 10Ω. 9 The proportion of Ω is 100%.

[0384] Example 2: Preparation of an anisotropic magnetic adhesive film:

[0385] (1) magnetic Preparation of sex particles

[0386] Preparation of (S-c1) Initial polymer particles: Emulsifier, stabilizer, and dispersion medium were added to the reaction vessel. After thorough stirring, nitrogen gas was introduced, and the temperature was raised to 100°C. A mixture of initiator, glycidyl methacrylate, trimethylolpropane trimethacrylate, and dispersion medium was then added to the reaction solution. After the addition was complete, the reaction continued for 3 hours. The initial polymer particles containing epoxy groups on their surface were then obtained by centrifugation and washing.

[0387] The emulsifier is sodium dodecylbenzenesulfonate, the stabilizer is polyvinyl alcohol, the initiator is ammonium persulfate, and the dispersion medium is isopropanol. The mass ratio of sodium dodecylbenzenesulfonate, polyvinyl alcohol, ammonium persulfate, glycidyl methacrylate, trimethylolpropane trimethacrylate, and isopropanol is 1:2:1:100:20:200.

[0388] Activation of (S-c2) initial polymer particles:

[0389] The initial polymer particles were added to water, followed by an activator at a mass ratio of 1:200 to the initial polymer particles. The reaction was carried out at 60°C with stirring for 120 minutes. After centrifugation and washing, activated polymer particles with thiol groups on the surface were obtained. The activator was H2S.

[0390] (S-c3) Constructing a metal layer on the surface of activated polymer particles:

[0391] The surface-activated polymer particles are dispersed in water, then hydrazine hydrate is added, followed by the dropwise addition of silver nitrate solution. The mixture is stirred and reacted for 50 minutes. The ratio of the activated polymer particles, water, hydrazine hydrate, and silver nitrate is 1:200:5:5. This yields functional particles with a silver-plated surface, which are then washed by centrifugation.

[0392] (2) Preparation of solvent-based epoxy resin adhesive coating solution:

[0393] Solid epoxy resin, liquid epoxy resin, latent curing agent, toughening agent, and solvent are mixed in a weight ratio of 1:5:0.2:0.1:10 and stirred evenly to obtain a solvent-based epoxy resin adhesive coating liquid.

[0394] The solid epoxy resin is a bisphenol solid epoxy resin, the liquid epoxy resin is bisphenol F epoxy resin 862, the latent curing agent is boron trifluoride and its ethylamine complex, the toughening agent is a core-shell plasticizer, and the solvent is dioxane.

[0395] (3) Preparation of anisotropic magnetic adhesive film:

[0396] Arrangement of (S-b1) functional particles

[0397] Functional particles were dispersed in cyclohexanone, and then a solvent-based epoxy resin adhesive coating solution was added. After stirring evenly, the mixture was coated onto a PET film. The mass ratio of polymer particles, cyclohexanone, and epoxy resin in the solvent-based epoxy resin adhesive coating solution was 1:20:5. After baking at 60°C and solvent drying, the film was stretched. The stretching ratio in both the X and Y directions was 5, and the X and Y directions were stretched at a 60° angle. The final projected distance between particles in the X and Y directions was controllably adjusted to 5 μm.

[0398] In the substrate after biaxial stretching, the orientation degree in the X direction is 3.2, the orientation degree in the Y direction is 6.8, the ratio of the orientation degree in the X direction to the orientation degree in the Y direction is 2.1, and the orientation angle relative to the X direction is 30°.

[0399] Here, the degree of orientation and the orientation angle are measured as described above.

[0400] Formation of (S-b2) anisotropic magnetic adhesive film

[0401] A layer of the solvent-based epoxy resin adhesive coating liquid is then coated on the pre-arranged functional particle initial adhesive film prepared in step (S-b1). After baking at 60°C and drying the solvent, the coating liquid is fused with the initial adhesive film prepared in step (S-b1) to obtain an anisotropic magnetic adhesive film with a total thickness of 50 μm.

[0402] For this anisotropic magnetically conductive film, the permeability in the Z direction was ≥200 and the permeability in the XY direction was ≤5 when tested using an Agilent RF network / spectrum / impedance analyzer 4396B and a magnetic material test fixture 16454A.

[0403] Example 3: An anisotropic thermally conductive adhesive, mainly comprising the following steps:

[0404] (1) Guide hot Preparation of sex particles

[0405] Preparation of (S-c1) initial polymer particles:

[0406] Emulsifier, stabilizer, and dispersion medium were added to the reaction vessel, and the mixture was stirred thoroughly. Nitrogen gas was then introduced, and the temperature was raised to 80°C. A mixture of initiator, glycidyl methacrylate, triethylene glycol diacrylate, and dispersion medium was then added to the reaction solution. After the addition was complete, the reaction continued for 2 hours. The resulting particles were then centrifuged and washed to obtain initial polymer particles with epoxy groups on their surface.

[0407] The emulsifier is polyoxyethylene ether, the stabilizer is polyvinyl alcohol, the initiator is ammonium persulfate, and the dispersion medium is water. The mass ratio of polyoxyethylene ether, polyvinyl alcohol, ammonium persulfate, glycidyl methacrylate, triethylene glycol diacrylate, and water is 1:1.5:0.8:80:15:150.

[0408] Activation of (S-c2) initial polymer particles:

[0409] The initial polymer particles were added to water, followed by an activator at a mass ratio of 1:100 to the polymer particles. The reaction was carried out at 50°C for 80 minutes with stirring. After centrifugation and washing, activated polymer particles with carboxyl groups on the surface were obtained. The activator was acetic acid.

[0410] (S-c3) Constructing a metal layer on the surface of activated polymer particles:

[0411] The surface-activated polymer particles are dispersed in water, sodium borohydride is added, and then copper sulfate solution is added dropwise. The mixture is stirred and reacted for 40 minutes. The ratio of polymer particles, water, sodium borohydride and copper sulfate is 1:100:2:2, which yields functional particles with copper-plated surfaces. The particles are then washed by centrifugation.

[0412] (2) Preparation of solvent-based (meth)acrylic resin adhesives:

[0413] (Meth)acrylic resin, crosslinking agent, thermal initiator, toughening agent, polymerization inhibitor and solvent are mixed in a weight ratio of 1:0.5:0.2:0.5:0.1:10 and stirred evenly to obtain solvent-based (meth)acrylic resin adhesive coating liquid.

[0414] Among them, the (meth)acrylic resin is a polyurethane-modified (meth)acrylic resin, the crosslinking agent is dipentaerythritol hexaacrylate, the initiator is diisobutyryl peroxide, and the polymerization inhibitor is diethylhydroxylamine.

[0415] (3) Preparation of anisotropic thermally conductive adhesive film:

[0416] Arrangement of (S-b1) functional particles

[0417] Gold-plated functional particles were dispersed in ethylene oxide, and then a solvent-based (meth)acrylic resin adhesive coating solution was added. After stirring evenly, the mixture was coated onto a PET film. The mass ratio of the functional particles, ethylene oxide, and (meth)acrylic resin in the solvent-based (meth)acrylic resin adhesive coating solution was 1:15:3. After baking at 50°C and solvent drying, the film was stretched. The stretching ratio in the X direction was 4, and the stretching ratio in the Y direction was 10, with a 30° angle stretch in both directions. The final projected distance between particles in the XY direction was controllably adjusted to 4 μm.

[0418] In the substrate after biaxial stretching, the orientation degree in the X direction is 2.8, the orientation degree in the Y direction is 7.3, the ratio of the orientation degree in the X direction to the orientation degree in the Y direction is 2.6, and the orientation angle relative to the X direction is 80°.

[0419] Here, the degree of orientation and the orientation angle are measured as described above.

[0420] Formation of (S-b2) anisotropic thermally conductive adhesive film

[0421] A solvent-based (meth)acrylic resin adhesive coating liquid is then coated onto the pre-arranged functional particle initial adhesive film prepared in step (S-b1). After baking at 40°C and drying the solvent, the coating liquid is fused with the initial adhesive film prepared in step (S-b1) to obtain an anisotropic thermally conductive adhesive film with a total thickness of 30 μm.

[0422] For this anisotropic thermally conductive adhesive film, the thermal conductivity in the Z direction was measured to be 105 W / (mK) using a thermal conductivity meter, while the thermal conductivity in the XY direction was less than 20 W / (mK). It is evident that by introducing copper particles with high thermal conductivity onto the surface, thermal conductivity is achieved in the Z direction, while non-thermal conductivity is achieved in the XY direction, thus realizing a good anisotropic thermal conductivity effect.

[0423] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved.

[0424] It should also be noted that each block in the block diagram and / or flowchart, as well as combinations of blocks in the block diagram and / or flowchart, can be implemented using hardware (such as circuits or ASICs (Application Specific Integrated Circuits)) that performs the corresponding function or action, or using a combination of hardware and software, such as firmware.

[0425] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0426] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for arranging particles, characterized in that, The method includes: A composite structure comprising an adhesive layer and a plurality of particles is formed on a stretchable substrate, wherein at least a portion of each particle is embedded in the adhesive layer; The extensible substrate supporting the composite structure is biaxially stretched such that the projections of each particle onto a plane formed by a first direction and a second direction of the substrate are separated from each other. Prior to the biaxial stretching, the thickness of the adhesive layer is 1 / 6 to 1 / 2 of the average particle size. The adhesive resin contained in the adhesive layer is a thermosetting epoxy resin or a thermosetting (meth)acrylic resin. When the adhesive resin contained in the adhesive layer is a thermosetting epoxy resin, the adhesive coating liquid forming the adhesive layer comprises solid epoxy resin, liquid epoxy resin, latent curing agent, toughening agent, and solvent. When the adhesive resin contained in the adhesive layer is a thermosetting (meth)acrylic resin, the adhesive coating liquid forming the adhesive layer includes (meth)acrylic resin, crosslinking agent, thermal initiator, toughening agent, polymerization inhibitor and solvent.

2. The particle arrangement method according to claim 1, characterized in that, The first direction and the second direction are perpendicular to each other in the plane they form.

3. The particle arrangement method according to claim 1 or 2, characterized in that, The plane formed by the first direction and the second direction is parallel to the surface of the substrate.

4. The particle arrangement method according to claim 1 or 2, characterized in that, In the substrate subjected to biaxial stretching, the ratio of the degree of orientation in the transverse direction to the degree of orientation in the longitudinal direction is 1 to 9.

9.

5. The particle arrangement method according to claim 1 or 2, characterized in that, In the substrate subjected to biaxial stretching, the ratio of the degree of orientation in the transverse direction to the degree of orientation in the longitudinal direction is 1.2 to 9.

6. The particle arrangement method according to claim 1 or 2, characterized in that, In the substrate subjected to biaxial stretching, the ratio of the degree of orientation in the transverse direction to the degree of orientation in the longitudinal direction is 1.5 to 8.

5.

7. The particle arrangement method according to claim 1 or 2, characterized in that, In the substrate subjected to biaxial stretching, the orientation angle relative to the transverse direction is 0~90°.

8. The particle arrangement method according to claim 1 or 2, characterized in that, The first direction is the transverse direction of the substrate, and the second direction is the longitudinal direction of the substrate.

9. The method for arranging particles according to claim 1 or 2, characterized in that, The composite structure is formed by applying an adhesive coating liquid that does not contain the particles onto the stretchable substrate and drying it to form an adhesive layer, and then covering the adhesive layer with the particles in such a way that at least a portion of them are embedded in the adhesive layer.

10. The method for arranging particles according to claim 1 or 2, characterized in that, The composite structure is formed by applying an adhesive coating liquid containing the particles onto the stretchable substrate and drying it.

11. The particle arrangement method according to claim 1 or 2, characterized in that, The extendable substrate is selected from at least one of polyethylene terephthalate resins, polybutylene terephthalate resins, polycarbonate resins, polypropylene resins, and polymethyl methacrylate resins.

12. The method for arranging particles according to claim 1 or 2, characterized in that, The particles are functional particles, and the functional particles include a core material and a metal layer covering the core material; The core material is formed of a polymer comprising units based on mono(meth)acrylate monomers with epoxy groups and units based on monomers with two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

13. The particle arrangement method according to claim 1 or 2, characterized in that, Prior to the biaxial stretching, the thickness tolerance of the adhesive layer is less than 0.05 μm.

14. The method for arranging particles according to claim 1 or 2, characterized in that, When performing the biaxial stretching, the stretching ratio is 1 to 20 times, and the stretching speed is 2 to 40 mm / min.

15. The method for arranging particles according to claim 1 or 2, characterized in that, After the biaxial stretching is performed, the distance between the projections of the particles onto a plane formed by the first and second directions of the substrate is greater than 0 μm and less than 25 μm.

16. A method for manufacturing an anisotropic functional adhesive film, characterized in that, The method includes: The particle arrangement method according to any one of claims 1-15 is used to arrange functionally conductive particles to form a stretched composite structure on a substrate. Another adhesive layer is formed on the stretched composite structure.

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