CN116120873A

CN116120873A - Particle alignment method, anisotropic functional adhesive film manufacturing method, functional particles, and functional adhesive film manufacturing method

Info

Publication number: CN116120873A
Application number: CN202111350161.XA
Authority: CN
Inventors: 邹海良; 彭蒙蒙; 周慧慧
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2023-05-16
Also published as: WO2023083202A1

Abstract

The present application relates to a method for arranging particles, a method for producing an anisotropic functional film, functional particles, and a method for producing the functional particles. The arrangement method of the particles comprises the following steps: forming a composite structure comprising 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; the extensible substrate carrying the composite structure is biaxially stretched such that the projections of each of the particles onto at least one plane of the substrate formed by the first and second directions are separated from each other. The anisotropic functional adhesive film of the present application is produced by the particle alignment method of the present application. The functional particles of the present application comprise a core material and a metal layer coating the core material; the core material is formed of a polymer containing a unit based on a mono (meth) acrylate monomer having an epoxy group and a unit based on a monomer having two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

Description

Particle alignment method, anisotropic functional adhesive film manufacturing method, functional particles, and functional adhesive film manufacturing method

Technical Field

The present invention relates to the field of a method for arranging particles, and more particularly, to a method for arranging particles, an anisotropic functional adhesive film, a method for producing an anisotropic functional adhesive film using the method for arranging particles, functional particles, and a method for producing the functional particles.

Background

In application fields of material science, chemistry and biology, it is often necessary to arrange particles (e.g. organic particles, inorganic particles, or organic/inorganic composite particles) in order to impart specific functions to the material carrying the particles, such as catalysis, optical filtering, optical absorption, electric/magnetic/thermal transport, gas adsorption, medicine, electric/magnetic recording, etc.

However, the arrangement of the particles often depends on the structure and composition of the particles themselves and the target material, and at the same time, the arrangement of the particles often requires higher costs, which limits the development of high performance products and increases the production costs. This is particularly true in the field of anisotropic functional adhesive films.

Anisotropic functional adhesive films are widely used in the electronics industry for packaging integrated circuits, particularly in various terminals such as tablet computers, notebook computers, digital cameras, mobile phones, wearable electronic devices, virtual reality devices, and the like. Along with miniaturization and high functionalization of various terminals, requirements for anisotropic functional adhesive films are also increasing. The anisotropic functional adhesive film comprises anisotropic conductive adhesive, anisotropic magnetic conductive adhesive, anisotropic heat conductive adhesive and the like. For example, the anisotropic conductive adhesive has important applications in display screens, cameras and the like, such as being used for electrical interconnection between an IC, an FPC/COF and the like and a display device in end products, and particularly with the development of display devices such as OLED, QLED, mini-LEDs, micro-LEDs and the like, the performance requirements of the anisotropic conductive adhesive are higher and higher. The anisotropic magnetic conductive adhesive is very important in the radio frequency module, and realizes excellent signal performance through the difference of magnetic or dielectric properties in all directions. The anisotropic heat-conducting adhesive can realize anisotropic heat dissipation effect on a mobile phone high-density integrated single board or a device. Here, the anisotropy means that it has conductivity with respect to electricity, magnetism, heat, and the like in a specific direction (e.g., a direction perpendicular to the surface of the adhesive film in the adhesive film, i.e., Z direction) and does not have conductivity in other directions (e.g., a direction parallel to the surface of the adhesive film in the adhesive film, i.e., XY direction).

The main principle of the anisotropic functional adhesive film is that functional particles are added into an adhesive and made into a film shape, and then the adhesive film has conductivity in the Z direction in the curing process, and only has an adhesive function in the XY direction but has no conductivity.

The arrangement method of the functional particles in the anisotropic functional adhesive film and the controllable preparation of the functional particles are core technologies focused in the technical field.

With respect to the arrangement of functional particles, random and matrix distribution is mainly used in the art. Because the random distribution mode is difficult to realize precise distribution (poor in uniformity and adjustability) of the functional particles, especially in the aspect of assembling high-precision devices, under the condition that the reliability of a functional layer of the traditional functional particles is poor and the hardness degree is difficult to adjust, the conduction is often blocked (especially the conductive adhesive film can generate a short circuit phenomenon), so that the performance of the anisotropic functional adhesive film containing the random distribution functional particles is poor. Therefore, in order to improve the accuracy, a matrix distribution method is generally used. As a matrix distribution method, various methods such as a magnetic control method, a template method, a photolithography method, a magnetic separation method and the like have been reported in the prior art. However, the prior reported matrix distribution mode has the problems of high cost, low yield and the like, and the distance adjustability between the particle sizes is poor. In addition, the matrix distribution method of the prior art sometimes causes damage to the functional layer outside the functional particles. Therefore, for the matrix distribution method of particles, especially for the matrix distribution method of functional particles in an anisotropic functional adhesive film, industry is continuously exploring new solutions to solve the technical problems of poor adjustability and uniformity of the distribution of functional particles in the adhesive film, complex process, low yield and impaired particle function.

On the other hand, regarding conventional functional particles, polymer particles such as polystyrene-based particles or polymethyl methacrylate-based particles are generally employed in the art as the basis of the functional particles. However, such polymer particles have low degree of softness, particle size and particle size distribution adjustability and uncontrollable surface roughness. Meanwhile, such polymer particles are inert, and thus are generally formed to have a metal layer formed on the surface thereof by electroless plating. However, such plating has environmental problems, and is complicated in process and high in manufacturing cost. In addition, the obtained metal plating layer has low reliability and is easy to fall off. Therefore, there is room for improvement in terms of improving the reliability of the surface metal layer while achieving the properties of morphology, hardness, size, distribution, and the like.

Disclosure of Invention

In view of this, a method of arranging particles is proposed, which can simply and orderly distribute various particles, has no damage to the particles themselves, is simple in process and high in yield, and is convenient for mass production.

The anisotropic functional adhesive film has the advantages that the functional particles can be easily uniformly distributed, the distribution mode of the functional particles in the adhesive film can be adjusted according to the requirement, the functional layers of the functional particles are not damaged, the process is simple, the yield is high, and the mass production is convenient.

The functional particles have the advantages that the molecular chain structure of the polymer core material of the functional particles is flexible and adjustable, and the binding force between the functional particles and the metal layer is strong, so that the functional particles can have the expected morphology and hardness degree according to the needs, the metal layer is not easy to fall off, and the reliability is strong; while the functional particles are of uniform size. Thus, the functional particles are particularly suitable for inclusion as functional particles in an anisotropic functional adhesive film (optionally in a random distribution or in a matrix distribution) so that the anisotropic functional adhesive film can combine excellent conductivity, precision and functional stability, and is suitable for different application scenarios.

Also provided is a method for producing functional particles, which can easily obtain functional particles with strong surface morphology and hardness degree adjustability, strong reliability of a metal layer and uniform size without constructing a protruding structure on the particle surface, is environment-friendly, has a simple flow, and is convenient for mass production.

The functional particles are obtained by a specific method, so that the molecular chain structure of the polymer core material of the functional particles is flexible and adjustable, and the binding force between the functional particles and the metal layer is strong, therefore, the functional particles can have the expected morphology and hardness degree according to the needs, the metal layer is not easy to fall off, and the reliability is strong; while the functional particles are of uniform size. Thus, the functional particles are particularly suitable for inclusion as functional particles in an anisotropic functional adhesive film (optionally in a random distribution or in a matrix distribution) so that the anisotropic functional adhesive film can combine excellent conductivity, precision and functional stability, and is suitable for different application scenarios.

An anisotropic functional adhesive film is also provided, which has excellent conductivity, precision and functional stability due to the inclusion of the functional particles, and is suitable for different application scenes.

In a first aspect, embodiments of the present application provide a method of arranging particles, the method comprising:

forming a composite structure comprising 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;

the extensible substrate carrying the composite structure is biaxially stretched such that the projections of each of the particles onto at least one plane of the substrate formed by the first and second directions are separated from each other.

Under the condition, various particles can be simply and conveniently distributed in order, the particles are not damaged, the process is simple, the yield is high, and the large-scale production is convenient.

In a first possible implementation manner of the arrangement method of particles according to the first aspect, the first direction and the second direction are perpendicular to each other in a plane formed by the first direction and the second direction.

In this case, various particles can be more simply and orderly distributed, and mass production is more facilitated.

In a first or two possible implementations of the method of arranging particles according to the first aspect, the one plane formed by the first direction and the second direction is parallel to the surface of the substrate.

In this case, various particles can be further easily and orderly distributed, further facilitating mass production.

According to the first aspect, in any one of the first to third possible implementation manners of the arrangement method of particles, in the substrate subjected to biaxial stretching, a ratio of a degree of orientation in a transverse direction to a degree of orientation in a longitudinal direction is 1 to 9.9.

In this case, the adjustability of the particle matrix is made more suitable and the arrangement method of the particles of the present application is made suitable for different applications.

According to the first aspect, in any one of the first to fourth possible implementation manners of the arrangement method of particles, in the substrate subjected to biaxial stretching, a ratio of a degree of orientation in a transverse direction to a degree of orientation in a longitudinal direction is 1.2 to 9.

In this case, the adjustability of the particle matrix is made more suitable and easier and the arrangement method of the particles of the present application is made suitable for different applications.

According to the first aspect, in any one of the first to fifth possible implementation manners of the arrangement method of particles, in the substrate subjected to biaxial stretching, a ratio of a degree of orientation in a transverse direction to a degree of orientation in a longitudinal direction is 1.5 to 8.5.

According to a first aspect, in any one of the first to sixth possible implementation manners of the arrangement method of particles, the orientation angle with respect to the transverse direction in the biaxially stretched substrate is 0 to 90 °.

According to a first aspect, in any one of the first to seventh possible implementation manners of the arrangement method of particles, the first direction is a lateral direction of the substrate, and the second direction is a longitudinal direction of the substrate.

According to a first aspect, in any one of the first to eighth possible implementation manners of the arrangement method of particles, the composite structure is formed by: an adhesive coating liquid that does not contain the particles is coated on the extensible substrate and dried to form an adhesive layer, and the particles are further covered on the adhesive layer in such a manner that at least a part thereof is embedded in the adhesive layer.

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

According to a first aspect, in any one of the first to eighth possible implementation manners of the arrangement method of particles, the composite structure is formed by: an adhesive coating liquid comprising the particles is coated on the extensible substrate and dried.

In this case, the arrangement of the particles can be more easily performed.

According to a first aspect, in any one of the first to tenth possible implementation manners of the arrangement method of particles, the extensible substrate is at least one selected from polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polypropylene resin, polymethyl methacrylate resin.

In this case, the particle matrix can be distributed more easily in an adjustable manner.

According to a first aspect, in any one of the first to eleventh possible implementation manners of the arrangement method of the particles, the particles are functional particles, the functional particles comprise a core material and a metal layer coating the core material;

the core material is formed of a polymer containing a unit based on a mono (meth) acrylate monomer having an epoxy group and a unit based on a monomer having two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

In this case, the arrangement method of the particles of the present application can be specifically used for preparing an anisotropic functional adhesive film.

According to a first aspect, in any one of the first to twelve possible implementations of the arrangement method of particles, the binder resin contained in the binder layer is a thermosetting epoxy resin or a thermosetting (meth) acrylic resin.

In this case, it may be more advantageous to immobilize the particles and to distribute the particle matrix in an adjustable manner more easily.

According to a first aspect, in any one of the first to thirteenth possible implementation manners of the arrangement method of the particles, before the biaxial stretching is performed, the thickness of the adhesive layer is 1/6 to 1/1 of the average particle diameter of the particles.

According to a first aspect, in any one of the first to fourteenth possible implementations of the method of arranging particles, the thickness tolerance of the adhesive layer is less than 0.05 μm before the biaxial stretching is performed.

In this case, the dimensional stability of the obtained particle matrix is improved, and the yield is further improved.

According to a first aspect, in any one of the first to fifteen possible implementation manners of the arrangement method of particles, the biaxial stretching is performed at a stretching magnification of 1 to 20 times and a stretching speed of 2 to 40mm/min.

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

According to a first aspect, in any one of the first to sixteen possible implementations of the method of arranging particles, after the biaxial stretching is performed, projections of the particles at least on one plane of the substrate made by the first direction and the second direction are more than 0 μm and 25 μm or less from each other.

In a second aspect, embodiments of the present application provide a method for manufacturing an anisotropic functional adhesive film, the method including:

aligning functional particles having functional conductivity using the method of aligning particles according to any one of the first to seventeen possible implementations of the first aspect to form a stretched composite structure on a substrate;

another adhesive layer is formed on the stretched composite structure.

Under the condition, the anisotropic functional adhesive film manufacturing method can easily enable the functional particles to be distributed uniformly, can adjust the distribution mode of the functional particles in the adhesive film according to the requirement, has no damage to the functional layers of the functional particles, is simple in process and high in yield, and is convenient for mass production.

According to a second aspect, in a first possible implementation of the method for manufacturing an anisotropic functional adhesive film, the adhesive layer comprised in the composite structure has the same composition as the further adhesive layer.

In this case, the adhesiveness of the anisotropic functional adhesive film of the present application can be further improved.

According to a second aspect, in the first or second possible implementation manner of the method for manufacturing an anisotropic functional film, the adhesive layer contained in the composite structure and the other adhesive layer are fused together to form a structure that coats the functional particles.

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

According to a second aspect, in any one of the first to third possible implementation manners of the method for manufacturing an anisotropic functional adhesive film, the overall thickness of the anisotropic functional adhesive film is 10 to 50 μm.

In this case, the anisotropic functional adhesive film of the present application better ensures excellent conductivity, precision, and functional stability.

According to a second aspect, in any one of the first to fourth possible implementation manners of the method for manufacturing an anisotropic functional adhesive film, the thickness of the anisotropic functional adhesive film is 3 to 15 times the average particle diameter of the functional particles.

According to a second aspect, in any one of the first to fifth possible implementation manners of the method for manufacturing an anisotropic functional film, the total mass of the functional particles is 1 to 15 mass% with respect to the total mass of the adhesive

In a third aspect, embodiments of the present application provide a functional particle, wherein the functional particle comprises a core material and a metal layer coating the core material;

Under the condition, the molecular chain structure of the polymer core material of the functional particle is flexible and adjustable, and the binding force between the functional particle and the metal layer is strong, so that the functional particle can have the expected morphology and hardness degree according to the need, the metal layer is not easy to fall off, and the reliability is strong; while the functional particles are of uniform size. Therefore, the functional particles are suitable to be contained in the anisotropic functional adhesive film as functional particles, so that the anisotropic functional adhesive film can have excellent conductivity, precision and functional stability and is suitable for different application scenes.

According to a third aspect, in a first possible implementation manner of the functional particles, the functional particles have an average particle size of 1-15 μm.

In this case, the functional particles are more advantageously suitable for use in anisotropic functional adhesive films.

According to a third aspect, in a first or two possible implementations of the functional particles, the functional particles have a roughened surface.

In a third possible implementation form of the functional particle according to the third aspect, the roughened surface has a roughened structure formed by a plurality of burr structures.

In this case, the functional particles have a more suitable surface morphology, and can provide more excellent conductivity when used in an anisotropic functional adhesive film.

According to a third aspect, in any one of the first to fourth possible implementation forms of the functional particles, the core material has a k30% hardness of 500 to 2500N/mm ² 。

According to a third aspect, in any one of the first to fifth possible implementation forms of the functional particles, the polymer has a degree of cross-linking of between 0.5 and 20%.

According to a third aspect, in any one of the first to sixth possible implementation forms of the functional particles, the ratio of the units based on the mono (meth) acrylate monomer with an epoxy group is 80 to 98 mass% with respect to the total structural units of the polymer.

In this case, the functional particles have a more suitable morphology and/or degree of hardness, and can provide a stronger binding force with the metal layer, with a stronger reliability.

According to a third aspect, in any one of the first to seventh possible implementations of the functional particle, the ratio of the units based on the monomer with two or more vinyl groups is 2 to 20 mass% with respect to the total structural units of the polymer.

In this case, the functional particles have a more suitable degree of softness.

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

In this case, the functional particles can provide more excellent conductivity and functional stability when used in an anisotropic functional adhesive film.

In a fourth aspect, embodiments of the present application provide a method for manufacturing functional particles according to any one of the first to nine possible implementations of the third aspect, wherein the method includes:

adding at least a mono (meth) acrylate monomer having an epoxy group and a monomer having two or more vinyl groups to a dispersion medium containing a surfactant to polymerize to form initial polymer particles;

activating epoxy groups on the surface of the initial polymer particles with an activator to form activated polymer particles;

the activated polymer particles are added to an aqueous metal compound solution and a metal layer is formed on the surface thereof with a reducing agent.

In this case, the manufacturing method of the present application can easily obtain functional particles with strong morphology and hardness degree adjustability, strong reliability of the metal layer, uniform size, environmental friendliness, simple flow, and convenience for mass production.

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

In this case, the manufacturing method of the present application can make the surface of the starting polymer particle have more suitable active groups, thereby making the metal layer more reliable without increasing the production cost.

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

In this case, the production method of the present application can more effectively activate the starting polymer particles.

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

In this case, the manufacturing method of the present application can more effectively form the metal layer.

In a fifth aspect, embodiments of the present application provide a functional particle, characterized in that the functional particle is obtained by a manufacturing method comprising:

Under the condition, the functional particles are obtained by a specific method, so that the molecular chain structure of the polymer core material of the functional particles is flexible and adjustable, and the binding force between the functional particles and the metal layer is strong, therefore, the functional particles can have the expected morphology and hardness degree according to the needs, the metal layer is not easy to fall off, and the reliability is strong; while the functional particles are of uniform size. Therefore, the functional particles are particularly suitable for being contained in the anisotropic functional adhesive film as functional particles, so that the anisotropic functional adhesive film can have excellent conductivity, precision and functional stability and is suitable for different application scenes.

In a sixth aspect, embodiments of the present application provide an anisotropic functional adhesive film that is a film-like adhesive material comprising a binder and functional particles according to any one of the first to nine possible implementations of the third aspect or functional particles according to the first possible implementation of the fifth aspect.

Under this condition, the anisotropic functional adhesive film of the application has the advantages of excellent conductivity, precision and functional stability no matter how the functional particles are arranged due to the inclusion of the functional particles which have strong shape and hardness degree adjustability, strong reliability of the metal layer and uniform size, and is suitable for different application scenes.

In a first possible implementation of the anisotropic functional adhesive film according to the sixth aspect, the functional particles are randomly dispersed in the adhesive.

In this case, the anisotropic functional adhesive film of the present application can be more easily formed.

In a first possible implementation manner of the anisotropic functional adhesive film according to the sixth aspect, the functional particles are distributed in such a way that projections at least on one plane of the adhesive film formed by the first direction and the second direction are separated from each other.

Under the condition, the anisotropic functional adhesive film can better have excellent conductivity, precision and functional stability and is suitable for different application scenes.

In a third possible implementation manner of the anisotropic functional adhesive film according to the sixth aspect, a distance between projections of the functional particles at least on a plane of the adhesive film formed by the first direction and the second direction is greater than 0 μm and less than 25 μm.

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

According to a sixth aspect, in any one of the first to fourth possible implementation manners of the anisotropic functional adhesive film, the thickness of the anisotropic functional adhesive film is 3 to 15 times the average particle diameter of the functional particles.

According to a sixth aspect, in any one of the first to fifth possible implementation forms of the anisotropic functional adhesive film, the total mass of the functional particles is 1 to 15 mass% with respect to the total mass of the adhesive.

In this case, the anisotropic functional adhesive film of the present application has more excellent conductivity, precision and functional stability.

According to a sixth aspect, in any one of the first to sixth possible implementation manners of the anisotropic functional adhesive film, the binder resin contained in the anisotropic functional adhesive film is a thermosetting epoxy resin or a thermosetting (meth) acrylic resin.

In this case, the anisotropic functional adhesive film of the present application further has more suitable adhesiveness.

According to a sixth aspect, in any one of the first to seventh possible implementation manners of the anisotropic functional adhesive film, the total thickness of the anisotropic functional adhesive film is 10 to 50 μm.

These and other aspects of the application will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features and aspects of the present application and together with the description, serve to explain the principles of the present application.

A schematic diagram of one example of the arrangement method of particles of the present application is shown in fig. 1 (the binder portion is omitted from the top view for simplicity).

An example of a method of manufacturing an anisotropic functional adhesive film is shown in fig. 2 (for simplicity, the adhesive portion is omitted in the top view).

An example of biaxial stretching in a multistage manner is shown in fig. 3 (the adhesive portion is omitted for brevity).

The functionality of the present application is shown in FIG. 4One specific example of the method for producing the particles (polymer particles are formed by using GMA and EDGMA as monomers, gold as metal, mercapto as an activating group, and sodium borohydride NaBH as a reducing agent) ₄ )。

An example of the initial polymer particles of the present application (using emulsion polymerization of GMA and EDGMA at 75 ℃) is shown in fig. 5.

FIG. 6 shows an example of a metal layer formed on activated polymer particles (gold as the metal, mercapto as the activating group, sodium borohydride NaBH as the reducing agent) ₄ )。

Fig. 7 shows the adhesive conduction principle of an anisotropic conductive film as an example of the anisotropic functional film of the present application.

Detailed Description

Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

In addition, numerous specific details are set forth in the following detailed description in order to provide a better understanding of the present application. It will be understood by those skilled in the art that the present application may be practiced without some of these specific details. In some instances, methods, means, elements, and circuits have not been described in detail as not to unnecessarily obscure the present application.

< first aspect >

In order to solve the above technical problems, the present application provides a method for arranging particles, the method comprising:

In the first aspect of the present application, for convenience, the term "Z direction" means a direction perpendicular to the surface of the substrate (i.e., thickness direction), the term "X direction" means a transverse direction of the substrate (sometimes referred to in the art as a width direction, or TD direction), the term "Y direction" means a longitudinal direction of the substrate (sometimes referred to in the art as a mechanical direction, or MD direction), and the term "XY direction" means a direction parallel to the surface of the substrate. In addition, by "surface of the substrate" is generally understood that surface which is used to carry the adhesive layer and the particles.

A schematic diagram of one example of the arrangement method of particles of the present application is shown in fig. 1. Of course, it is understood that the arrangement method of the particles of the present application is not limited to the example shown in fig. 1.

The respective steps will be described in detail below.

(formation of composite Structure (S-a 1) on extensible substrate)

As described above, a composite structure comprising an adhesive layer and a plurality of particles, each of which has at least a portion embedded therein, is formed on an extensible substrate. As an example, as shown in step S-a1 of the example in fig. 1.

In the S-a1 step, the specific kind of the stretchable substrate is not particularly limited and may be those known in the art as long as biaxial stretching described later can be achieved. In some preferred embodiments, the extensible substrate is preferably at least one selected from the group consisting of polyethylene terephthalate-based resin, polybutylene terephthalate-based resin, polycarbonate-based resin, polypropylene-based resin, polymethyl methacrylate-based resin, from the viewpoint that the particle matrix can be more easily distributed in an adjustable manner.

In the step S-a1, the specific kind of particles is not particularly limited, and may be used for the arrangement of various particles and appropriately adjusted according to the specific use of the particle arrangement method of the present application. Examples of particles include, but are not limited to: metal particles such as gold, silver, copper, aluminum, etc.; inorganic particles such as silicon, silica, alumina, barium sulfate, and ferroferric oxide; organic particles such as styrene-based polymers, (meth) acrylate-based polymers, and silicone-based polymers; organic/inorganic composite particles; organic/metal composite particles; inorganic/metal composite particles, and the like. These particles may be used singly or in combination of two or more.

In the S-a1 step, there is no particular limitation on the specific shape of the particles, and examples of the shape include, but are not limited to, spherical, spheroidal, or other regular or irregular shapes.

In the step S-a1, the average size (e.g., average particle diameter) of the particles and the distribution thereof are not particularly limited, and may be appropriately adjusted according to the specific use of the method for arranging particles of the present application.

In some preferred embodiments, where the methods of alignment of the particles of the present application are used to prepare anisotropic functional adhesive films, the particles are preferably functional particles having functional conductivity (e.g., electrical conductivity, magnetic conductivity, thermal conductivity, etc.). In some more preferred embodiments, the functional particles are as described in the following < third aspect > or < fifth aspect >, and are not described here.

In the S-a1 step, the specific kind of the adhesive forming the adhesive layer is not particularly limited, and various adhesives known in the art may be used. In some preferred embodiments, a thermosetting adhesive is preferably employed, examples of which include, but are not limited to, epoxy-based adhesives, (meth) acrylic-based adhesives, isocyanate-based adhesives, silicone-based adhesives, polyurethane-based adhesives, and the like. Here, "X-based adhesive" means an adhesive formed using an X compound (or polymer) as an adhesive component (e.g., an adhesive resin), which optionally contains other components in addition to the X compound (or polymer).

In some preferred embodiments, the binder resin contained in the binder layer is a thermosetting epoxy resin (i.e., the binder used in the binder layer is a thermosetting epoxy resin-based binder) or a thermosetting (meth) acrylic resin (i.e., the binder used in the binder layer is a (meth) acrylic resin-based binder) from the standpoint that it is more advantageous to fix the particles and to distribute the matrix of particles more easily in an adjustable manner. Here, the term "(meth) acrylic" encompasses (meth) acrylic acid, (meth) acrylate, and the like.

In some specific embodiments, where the adhesive employed in the adhesive layer is a thermosetting epoxy resin-based adhesive, the adhesive preferably originates from a solvent-based epoxy material adhesive coating liquid, and the solvent-based epoxy material adhesive coating liquid preferably comprises a solid epoxy resin, a liquid epoxy resin, a latent curing agent, a toughening agent, and a solvent. In some more preferred embodiments, the weight ratio of solid epoxy resin, liquid epoxy resin, latent hardener, toughening agent, and solvent (solid epoxy resin: liquid epoxy resin: latent hardener: 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, the solvent type epoxy resin material adhesive coating liquid is preferably obtained by blending and uniformly stirring the constituent components by means generally employed in the art from the viewpoint of cost reduction.

The solid epoxy resin is any solid epoxy resin known in the art, and in some specific embodiments is preferably at least one selected from the group consisting of solid bisphenol-based epoxy resins, solid novolac epoxy resins (e.g., o-cresol novolac epoxy resins, etc.), biphenyl epoxy resins, fused ring epoxy resins, and dicyclopentadiene phenol-based epoxy resins.

The liquid epoxy resin described above is any liquid epoxy resin known in the art, and 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.

The latent curing agent is any of those known in the art, and in some specific examples, is preferably at least one selected from boron trifluoride and its ethylamine complex, amines (e.g., 4 '-diamino-3, 3' -diethyldiphenylmethane, etc.), imidazoles (e.g., dimethylimidazole, diphenylimidazole, etc.), anhydrides (e.g., (meth) tetrahydrophthalic anhydride, (meth) hexahydrophthalic anhydride, (meth) nadic anhydride, etc.).

The toughening agent is any toughening agent known in the art. In some specific embodiments, examples of toughening agents include, but are not limited to, nitrile rubber based toughening agents, silicone based toughening agents, polyurethane based toughening agents, and the like. Additionally, in other specific embodiments, the toughening agent is a core shell structure toughening agent or a homogeneous toughening agent. Furthermore, in the case where the weight average molecular weight of the toughening agent can be measured, the weight average molecular weight of the toughening agent is preferably between 2000 and 20000. These toughening agents may be used alone or in combination of two or more.

The above solvent is preferably at least one selected from cyclohexanone, chloroform, ethyl acetate, toluene, methylene chloride, chloroform, tetrahydrofuran, ethylene oxide, acetone, and dioxane.

In other specific embodiments, in the case where 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 includes a (meth) acrylic resin, a crosslinking agent, a thermal initiator, a toughening agent, a polymerization inhibitor, and a solvent. In some more preferred embodiments, the weight ratio of (meth) acrylic resin, crosslinker, thermal initiator, toughening agent, polymerization inhibitor, and solvent ((meth) acrylic resin: crosslinker: 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 other more preferred embodiments, the solvent-based (meth) acrylic resin adhesive coating liquid is preferably obtained by blending and stirring uniformly the constituent components by means generally employed in the art from the viewpoint of cost reduction.

The above (meth) acrylic resin is any (meth) acrylic resin known in the art as useful as a binder resin, preferably an oligomer having a (meth) acrylate structure, and has a weight average molecular weight of between 2000 and 20000.

The above-mentioned crosslinking agent is any crosslinking agent known in the art, and in some specific embodiments, it is preferable that the (meth) acrylic acid ester containing two or more double bonds is exemplified by, but not limited to, tricyclodecanedimethanol diacrylate, trimethylolpropane trimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, trimethylolpropane tetraacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1, 4-butanediol diacrylate, and neopentyl glycol diacrylate. These crosslinking agents may be used singly or in combination of two or more.

The above-mentioned initiator used in the solvent-based (meth) acrylic resin adhesive coating liquid is any radical-type initiator known in the art, and in some specific examples, is preferably a peroxide-type initiator, examples of which include, but are not limited to, diisobutyryl peroxide, cumyl peroxyneodecanoate, bis (3-methoxybutyl) peroxydicarbonate, bis (ethoxyhexyl) peroxydicarbonate, 1, 3-tetramethylbutyl peroxyneodecanoate, bis (4-t-butylcyclohexyl) peroxydicarbonate, bitetradecyl peroxydicarbonate, t-butyl peroxy-2-ethylhexanoate, t-amyl 1, 1-di-t-butylperoxy-3, 5-trimethylcyclohexane, t-amyl peroxy (2-ethylhexyl) carbonate, butyl 4, 4-bis (t-butylperoxy) valerate, t-butyl peroxybenzoate, 2, 5-di-t-butylperoxy-2, 5-dimethylhexane, di-t-butylperoxy, methyl isobutyl ketone, cyclohexanone peroxide and cyclohexanone peroxide. These initiators may be used singly or in combination of two or more.

The above polymerization inhibitor is any polymerization inhibitor known in the art, and in some specific embodiments, is preferably at least one selected from the group consisting of diethylhydroxylamine, nitrobenzene, hydroquinone, p-hydroxyanisole, 2,6 di-t-butyl p-cresol.

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

In some preferred embodiments, 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 of the particles, and still more preferably 1/6 to 1/4 of the average particle size of the particles, prior to biaxial stretching.

Additionally, in some preferred embodiments, the thickness tolerance of the adhesive layer in the composite structure is preferably less than 0.05 μm prior to biaxial stretching.

In some specific embodiments, from the standpoint that the matrix distribution of particles can be controlled more effectively, as shown in the upper half of step S-a1 in fig. 1, the composite structure is preferably formed by: an adhesive coating liquid containing no particles is coated on the extensible substrate and dried to form an adhesive layer, and the particles are coated on the adhesive layer in such a manner that at least a part of the particles are embedded in the adhesive layer. In this case, the coating method of the adhesive coating liquid is not particularly limited, and the coating method includes, but is not limited to, brush coating, dip coating, spin coating, bar coating, blade coating, curtain coating, screen printing, spray coating, slit coating, and the like. These coating methods may be used alone or in combination of two or more. In addition, in this case, the coating method of the functional particles is not particularly limited, and for example, a coating method such as a dip coating method, a spray coating method, or a deposition method may be employed. These covering methods may be used alone or in combination of two or more.

In other specific embodiments, from the standpoint that the alignment of particles can be more easily performed, as shown in the lower half of step S-a1 in fig. 1, the composite structure is preferably formed by: an adhesive coating liquid comprising the particles is coated on the extensible substrate and dried. In this case, the coating method includes, but is not limited to, a brush coating method, a dip coating method, a spin coating method, a bar coating method, a blade coating method, a curtain coating method, a screen printing coating method, a spray coating method, a slit coating method, and the like. These coating methods may be used alone or in combination of two or more. In addition, there is no particular limitation on the preparation method of the binder coating liquid containing particles, and in some preferred embodiments, the binder coating liquid containing particles is preferably prepared by mixing functional particles with the binder coating liquid by a method known in the art.

In the S-a1 step, there is no particular limitation on the manner of distribution of the particles in the composite structure, and in some preferred embodiments, the plurality of particles are preferably distributed in such a manner that at least a portion thereof is closely arranged.

In the step S-a1, there is no particular limitation on the drying method, and drying methods known in the art, such as air drying, oven drying, etc., may be employed. In some preferred embodiments, the drying temperature is preferably 40-60 ℃, and the drying time is preferably 0.1-3 hours, more preferably 0.5-2 hours. In this step, in the case of using a thermosetting adhesive, the drying process does not cause curing of the thermosetting adhesive.

(biaxial stretching (S-a 2))

As described above, the extensible substrate carrying the composite structure described above is biaxially stretched such that the projections of each of the particles onto at least one plane of the substrate formed by the first and second directions are separated from each other. As an example, as shown in step S-a2 of the example in fig. 1.

In this application, "the projections of each of the particles onto at least one plane of the substrate formed by the first direction and the second direction are separated from each other" means that the following exists: in addition to a plane formed by the first direction and the second direction, the projections of the particles and the particles on at least one other plane of the substrate are also separated from each other.

In addition, in some preferred embodiments, the plurality of particles are preferably arranged in a matrix in the form of a monolayer at least on one plane of the substrate formed by the first direction and the second direction after biaxial stretching, but 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 centers of other particles, but that the projections of each particle at least on that plane of the substrate are separated from each other.

In addition, in the present application, in the biaxially stretched composite structure, there is no particular limitation on the angles of the first direction and the second direction, and both of them. In some preferred embodiments, the first direction and the second direction are preferably perpendicular to each other in a plane formed by them from the standpoint that various particles can be more easily distributed in order, and mass production is more facilitated. In other preferred embodiments, a plane formed by the first direction and the second direction is parallel to the surface of the substrate for the same purpose. More preferably, the first direction is the transverse direction of the substrate and the second direction is the longitudinal direction of the substrate.

It is noted herein that the above-described first direction and second direction in the biaxially stretched composite structure do not necessarily correspond to the two stretching directions of biaxial stretching (i.e., the first direction and second direction respectively correspond to the two stretching directions of biaxial stretching, or at least one of the first direction and second direction does not correspond to the two stretching directions of biaxial stretching).

In the present application, the arrangement of the particles can be achieved at low cost by the stretching process, and the projection distance between the particles can be adjusted with the degree of stretching and the stretching angle in at least one plane formed by the first direction and the second direction.

In the S-a2 step, there is no particular limitation on the stretching method used, and biaxial stretching methods known in the art may be used. Specifically, fixed end stretching may be employed, or free end stretching may be employed.

In the S-a2 step, biaxial stretching may be performed in any direction (XY direction) perpendicular to the Z direction of the substrate, as long as projections of each particle on at least one plane of the substrate made of the first direction and the second direction are separated from each other. In addition, in the application, a connecting line between projection centers of any two adjacent particles can form any angle relative to the X direction. For example, as shown in fig. 1, the stretching direction may be the X direction and the Y direction (as in (S-a 2) in fig. 1), or other directions at an arbitrary angle with respect to the X direction in the XY direction.

In the S-a2 step, there is no particular limitation on the stretching mode, and the stretching mode may be an air stretching mode or may be an underwater stretching mode.

In the step S-a2, biaxial stretching may be simultaneous biaxial stretching or sequential biaxial stretching (for example, stretching in the Y direction is performed first and then stretching in the X direction is performed). In addition, the stretching step (S-a 2 step) may be performed in one stage, or may be performed in a plurality of stages (for example, stretching may be performed at a specific angle to adjust the angle after biaxial stretching in the X-direction and the Y-direction, as shown in the example of fig. 2). When stretching is performed in a plurality of stages, for example, the above-described free-end stretching and fixed-end stretching may be combined, and the above-described in-water stretching mode and in-air stretching mode may be also combined. When stretching is performed in a plurality of stages, the stretching ratio (maximum stretching ratio) described later is a product of the stretching ratios of the respective stages.

In the S-a2 step, the stretching temperature may be set to any appropriate value depending on, for example, the formation material of the base material, the specific composition of the particles, the stretching mode, and the like. In some preferred embodiments, the stretching temperature is 40-60 ℃.

In some preferred embodiments, the biaxial stretching is performed at a stretch ratio of 1 to 20 times, more preferably 1 to 10 times, in each stretching direction (e.g., X-direction, Y-direction, or other direction perpendicular to Z-direction) relative to the original dimension of the stretchable substrate.

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

In some preferred embodiments, the ratio of the degree of orientation in the X direction (TD direction) to the degree of orientation in the Y direction (MD direction) of the biaxially stretched substrate after undergoing step S-a2 is preferably 1 to 9.9, and may be, for example, 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, 8.0, 9.1, 9.3, 9.5, 9.6, 9.8, 9.9.9, etc. Here, the range between any two points and the engineering implementation error are all within the scope of the present application. In addition, the ratio of the degree of orientation in the X direction (TD direction) to the degree of orientation in the Y direction (MD direction) of the biaxially stretched substrate is more preferably 1.2 to 9, still more preferably 1.5 to 8.5, still more preferably 1.8 to 8, even more preferably 2 to 7.8, even more preferably 2.5 to 7. In these preferred embodiments, the alignment of particles can be flexibly performed while suppressing deterioration of the quality of the substrate, and the cost is sometimes reduced.

The degree of orientation of the substrate in the X direction and the degree of orientation of the substrate in the Y direction are not particularly limited as long as the ratio of the degrees of orientation can be satisfied. In some preferred embodiments, the substrate preferably has an orientation degree in the X direction of 1.5 to 8, more preferably 1.8 to 7, still more preferably 2 to 6, and still more preferably 2.5 to 5. In other preferred embodiments, the substrate preferably has a Y-direction orientation of 1.5 to 8, more preferably 1.8 to 7, still more preferably 2 to 6, and still more preferably 2.5 to 5. In these preferred embodiments, the alignment of particles can be performed more flexibly while suppressing deterioration of the quality of the substrate.

In addition, in some preferred embodiments, after undergoing the S-a2 step, the biaxially stretched substrate is preferably oriented at an angle of 0 to 90 °, more preferably 0 to 80 °, still more preferably 0 to 70 °, still more preferably 0 to 60 °, relative to the X-direction. In these preferred embodiments, the alignment of particles can be flexibly performed while suppressing deterioration of the quality of the substrate, and the cost is sometimes reduced.

In the present application, the degree of orientation and the angle of orientation are measured by a molecular orientation meter, for example, the molecular orientation meter MOA-8000 series of prince measuring instruments.

In some preferred embodiments, after the biaxial stretching, the particles have a distance between at least one projection of the particles onto a plane of the substrate formed by the first and second directions (i.e. the distance between the nearest two points between two adjacent projections) of more than 0 μm and less than 25 μm, more preferably 1 μm to 15 μm, still more preferably 2 μm to 10 μm.

(specific examples)

In some particularly preferred embodiments, the method of aligning particles of the present application comprises the steps of:

s-a1 step: (1) coating an adhesive layer on a surface of a stretchable substrate: coating the solution type adhesive on a substrate, and baking at 40-60 ℃ for 30-120 min, wherein the thickness of the obtained adhesive layer is 1/4-1/2 of the particle diameter, and the thickness tolerance of the adhesive is 0.05 mu m; (2) compact arrangement of particles: the particles are closely arranged in the adhesive layer by a Dip Coating method (Dip Coating) or a precipitation method; and

s-a2 step: a substrate double-pulling process: placing the coated substrate into a film double-drawing device, and drawing at a temperature of 40-60 ℃ by controlling the drawing multiplying power and the drawing speed (the multiplying power is 1-20 times and the drawing speed is 2-40 mm/min) in the XY direction, so that the controllable arrangement of particles can be realized;

Or alternatively

S-a1 step: dispersing the particles in a solvent A, adding a solution type adhesive, uniformly stirring, coating the mixture on the surface of a stretchable substrate, and baking the mixture at 40-60 ℃ for 30-120 min to obtain an adhesive layer with the thickness of 1/4 to 1/2 of the particle diameter and the thickness tolerance of 0.05 mu m; and

s-a2 step: biaxial stretching was performed in the same manner as above.

< second aspect >

The application provides a manufacturing method of an anisotropic functional adhesive film, which comprises the following steps:

aligning functional particles having functional conductivity using the alignment method of particles described in the above < first aspect > to form a stretched composite structure;

another adhesive layer is formed on the stretched composite structure.

An example of a method of manufacturing an anisotropic functional adhesive film is shown in fig. 3. Of course, it is understood that the method of manufacturing the anisotropic functional adhesive film of the present application is not limited to the example shown in fig. 3.

The respective steps will be described in detail below.

(formation of stretched composite Structure (S-b 1))

As described above, the particles are aligned using the alignment method of particles described in the above < first aspect >, except that functional particles having functional conductivity are used as the particles to be aligned. Specifically, in this step, a composite structure including an adhesive layer (hereinafter sometimes referred to as an adhesive layer a) and functional particles, at least a portion of each functional particle being embedded in the adhesive layer a, is formed on an extensible substrate; the extensible substrate carrying the composite structure is biaxially stretched such that the projections of each functional particle onto at least one plane of the substrate made by the first and second directions are separated from each other, thereby forming a stretched composite structure comprising an adhesive layer a and aligned functional particles. As shown in the example of FIG. 3, the S-b1 step may be implemented by the S-a1 step and the S-a2 step.

In step S-b1, in some preferred embodiments, the plurality of functional particles are preferably arranged in a matrix in the form of a monolayer on at least one plane of the substrate made up of the first direction and the second direction, 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 centers of the other functional particles, but that the projections of each functional particle on at least one plane of the substrate made up of the first direction and the second direction are separated from each other.

In the S-b1 step, details of the extensible base material and the method of forming the stretched composite structure are the same as those in the arrangement method of the particles described in the above < first aspect >.

In the S-b1 step, the specific kind of the functional particles is not particularly limited as long as it is functional particles having functional conductivity (e.g., electrical conductivity, magnetic conductivity, thermal conductivity, etc.) that are known in the art to be useful in anisotropic functional adhesive films.

In some preferred embodiments, the functional particles are preferably functional particles as described in the following < third aspect > or < fifth aspect >, which are not described here.

In the present application, there is no particular limitation on the specific kind of adhesive used in the adhesive layer a, and those generally used in the art for forming an anisotropic functional adhesive film can be employed.

In some preferred embodiments, the adhesive used to form the adhesive layer a is preferably thermosetting, examples of which include, but are not limited to, epoxy-based adhesives, (meth) acrylic-based adhesives, isocyanate-based adhesives, silicone-based adhesives, polyurethane-based adhesives, and the like.

In some more preferred embodiments, the adhesive resin contained in the adhesive layer a is a thermosetting epoxy resin (i.e., the adhesive used in the adhesive layer a is a thermosetting epoxy resin-based adhesive) or a thermosetting (meth) acrylic resin (i.e., the adhesive used in the adhesive layer a is a (meth) acrylic resin-based adhesive). The details of these binders are the same as in the arrangement method of the particles described in the above < first aspect >.

The adhesive layer a of the anisotropic functional adhesive film of the present application may contain other components as needed in addition to the adhesive and the functional particles within a range that does not impair the technical effects of the present application. Examples of such other components include, but are not limited to, inorganic and/or organic particles other than the functional particles of the present application (which optionally have conductivity to electricity, heat, magnetism), various tackifying resins, crosslinking accelerators, silane coupling agents, anti-aging agents, colorants (e.g., pigments or dyes), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, antistatic agents, fibers, and the like. These other components may be used singly or in combination of two or more.

The amounts of these other components may be appropriately adjusted according to the actual needs.

(formation of another adhesive layer (S-b 2))

As described above, another adhesive layer (hereinafter sometimes referred to as adhesive layer B) is formed on the stretched composite structure, as shown in step S-B2 of the example in fig. 3.

In the S-B2 step, there is no particular limitation on the method of forming the adhesive layer B. For example, the adhesive layer B may be formed separately and then coated on the stretched composite structure; the adhesive layer B may be formed by applying a coating liquid for forming the adhesive layer B to the stretched composite structure.

In some preferred embodiments, the adhesive layer B is preferably formed by: the adhesive coating liquid is coated on the stretched composite structure and dried to form an adhesive layer B. In this case, the coating method of the adhesive coating liquid is not particularly limited, and the coating method includes, but is not limited to, brush coating, dip coating, spin coating, bar coating, blade coating, curtain coating, screen printing, spray coating, slit coating, and the like. These coating methods may be used alone or in combination of two or more.

In the S-B2 step, the composition of the adhesive layer B and the adhesive layer a described above may be the same or may be different. In some preferred embodiments, the adhesive layer B is identical in composition to the adhesive layer a described above from the standpoint that the adhesiveness of the anisotropic functional adhesive film of the present application can be further improved and stability is ensured.

In some preferred embodiments, from the standpoint that the adhesiveness and mechanical properties of the anisotropic functional adhesive film of the present application can be further improved, as shown in fig. 3, the adhesive layer B is integrated with the above-described adhesive layer a, forming a structure of coating functional particles.

In this application, in the case where at least one of the adhesive layer a and the adhesive layer B contains a thermosetting adhesive, the thermosetting adhesive in the anisotropic functional adhesive film obtained in this step is preferably uncured, and may be cured before or during the use of the adhesive film as required.

Furthermore, in some preferred embodiments, in the anisotropic functional adhesive film of the present application, the distance between the projections of the functional particles at least on one plane formed by the first direction and the second direction is preferably greater than 0 μm and 25 μm or less, more preferably 1 μm to 15 μm, still more preferably 2 μm to 10 μm.

In some preferred embodiments, after the formation of the adhesive layer B described above, the thickness of the resulting anisotropic functional adhesive film is preferably 10 to 50 μm. In addition, in some preferred embodiments, after the formation of the above adhesive layer B, the thickness of the resulting anisotropic functional adhesive film is preferably 3 to 15 times the average particle diameter of the functional particles.

In some preferred embodiments, after the formation of the above-described adhesive layer B, the resultant anisotropic functional adhesive film preferably has a total mass of the functional particles of 1 to 15 mass%, more preferably 1 to 10 mass%, still more preferably 2 to 8 mass%, relative to the total mass of the adhesives (all adhesives used in the adhesive layers a and B).

(other steps)

The method of manufacturing the anisotropic functional adhesive film of the present application may further include other steps within a range that does not impair the technical effects of the present application.

In some specific embodiments, the releasable protective film is coated on at least one of the surfaces of the adhesive film exposed to air before and/or after the adhesive layer B is formed.

< third aspect >

The present application provides a functional particle, wherein the functional particle comprises a core material and a metal layer coating the core material; the core material is formed of a polymer containing a unit based on a mono (meth) acrylate monomer having an epoxy group and a unit based on a monomer having two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer.

In this case, the polymer core of the functional particles of the present application comprises specific two structural units, so that the molecular chain structure is flexible and tunable, and can be chemically bonded to the metal in the metal layer based on the active groups converted by the epoxy groups on the surface thereof. Therefore, the functional particles can have the expected morphology and hardness degree according to the requirement, the metal layer is not easy to fall off, and the reliability is high. Meanwhile, the manufacturing method of the functional particles is stable and simple, and the obtained functional particles have uniform size. Therefore, the functional particles are suitable for being contained in the anisotropic functional adhesive film as functional particles, so that the anisotropic functional adhesive film can have excellent conductivity, precision and functional stability and is suitable for different application scenes.

In this application, the functional particles are preferably particles having a spherical shape or a spheroid shape. The average particle diameter of the functional particles is not particularly limited and may be appropriately adjusted according to the specific use thereof. In some preferred embodiments, the functional particles preferably have an average particle diameter of 1 to 15 μm, more preferably 1 to 10 μm, still more preferably 3 to 10 μm, from the viewpoint of being more suitable as functional particles used in the anisotropic functional adhesive film. In addition, in other preferred embodiments, the particle size distribution of the functional particles is preferably +/-1.5 μm, more preferably +/-1 μm, still more preferably +/-0.5 μm from the standpoint of being more suitable as functional particles for use in anisotropic functional adhesive films. Here, "+/-X μm" means a range of (R-X) μm to (R+X) μm, where R is the average particle diameter of the functional particles.

Here, the "average particle size" and "particle size distribution" are measured by means well known in the art, and can be measured, for example, by a commercial particle size analyzer or an electron scanning microscope.

In the present application, the surface morphology of the functional particles is not particularly limited, and may be appropriately adjusted according to actual needs. In some preferred embodiments, the functional particles have a roughened surface.

In the present application, by "roughened surface" is meant that the surface of the functional particles of the present application has upward protrusions or downward depressions (having a concave-convex structure) relative to an absolutely smooth curved surface. In the present application, the specific structure of the roughened surface of the functional particle is not particularly limited, and for example, the roughened surface may have a random uneven structure or a regular uneven structure. In addition, the surface structure may be determined by the morphology of the polymer core itself, or may be obtained by other treatments. In some preferred embodiments, the roughened surface structure of the functional particles of the present application is determined by the morphology of the polymer core itself from a cost reduction standpoint.

In some preferred embodiments, from the standpoint of enabling the functional particles to have a more suitable surface morphology, which can provide more excellent conductivity when used in an anisotropic functional adhesive film, the roughened surface of the functional particles preferably has a roughened structure formed of a plurality of burr structures, more preferably, the roughened surface of the functional particles is entirely a roughened structure formed of a plurality of burr structures. Here, the "burr structure" means a structure in which a cross-sectional area of a protrusion parallel to a direction away from the center of a particle becomes gradually smaller based on a true spherical surface having a radius of a minimum radius of the particle (a minimum distance between the particle surface and the center of the particle).

The polymer core material and the metal layer of the functional particles of the present application will be described in detail below.

(core material)

As described above, the core material contained in the functional particles of the present application is formed of a polymer containing a unit based on a mono (meth) acrylate monomer having an epoxy group and a unit based on a monomer having two or more vinyl groups.

In the present application, the unit based on the mono (meth) acrylate monomer having an epoxy group (hereinafter sometimes referred to as structural unit a) is a structural unit derived from the mono (meth) acrylate monomer having an epoxy group.

In the present application, the specific type of the mono (meth) acrylate monomer having an epoxy group is not particularly limited, and may be appropriately selected according to actual needs. In some preferred embodiments, the mono (meth) acrylate monomer bearing an epoxy group is preferably represented by the following formula a.

Wherein R is ₁ Is methyl or hydrogen atom, R ₂ Is an aliphatic alkylene group having 1 to 12 carbon atoms, an aliphatic oxaalkylene group having 1 to 12 carbon atoms, or an alicyclic alkylene group having 3 to 12 carbon atoms, Q is an epoxy group having 3 to 6 carbon atoms, and Q and R are each ₂ Can be connected by single bond, or at R ₂ Is a cycloaliphatic alkylene group, and forms a ring structure.

In some more preferred embodiments, the mono (meth) acrylate monomer bearing an epoxy group is more preferably glycidyl (meth) acrylate or 2, 3-epoxycyclohexylmethyl (meth) acrylate, still more preferably glycidyl (meth) acrylate, from the standpoint of cost and structural adjustability.

In the present application, the unit based on a monomer having two or more vinyl groups (hereinafter sometimes referred to as a structural unit B) is a structural unit derived from a monomer having two or more vinyl groups.

In the present application, the specific kind of the monomer having two or more vinyl groups is not particularly limited, and may be appropriately selected according to actual needs. In some preferred embodiments, the monomer having two or more vinyl groups is at least one selected from the group consisting of 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.

Examples of the above polyvalent (meth) acrylate monomers include, but are not limited to, tricyclodecanedimethanol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane 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, neopentyl glycol di (meth) acrylate, and the like.

Examples of the above polyvalent vinyl ester monomers include, but are not limited to, divinyl oxalate, divinyl malonate, divinyl succinate, divinyl glutarate, divinyl adipate, divinyl pimelate, divinyl suberate, divinyl azelate, divinyl sebacate, divinyl dodecanoate, trivinyl benzoates and the like.

Examples of the polyvalent vinyl ether monomer 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, neopentyl glycol divinyl ether

Examples of the above polyvalent olefin monomers include, but are not limited to, divinylbenzene, trivinylbenzene, and the like.

In some more preferred embodiments, the monomer having two or more vinyl groups is at least one selected from the group consisting of 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.

The polymer may contain, in addition to the above-mentioned structural units a and B, units based on other comonomers (hereinafter sometimes also referred to as structural units C) without impairing the technical effects of the present application. In general, the specific kind of the other comonomer is not particularly limited as long as it can polymerize with the above-mentioned mono (meth) acrylate monomer having an epoxy group and the above-mentioned monomer having two or more vinyl groups.

Generally, examples of such other comonomers include, but are not limited to: mono-olefin monomers such as ethylene, propylene, butene, styrene, p-methylstyrene, α -methylstyrene, p-methoxystyrene, benzyl chlorostyrene, 4-t-butylstyrene, etc.; conjugated diene monomers such as butadiene and isoprene; mono (meth) acrylate monomers having no epoxy group 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; (meth) acrylamide monomers such as N-phenylacrylamide, N-phenylmethacrylamide, N-benzylacrylamide, N- (4-chlorophenyl) acrylamide, N-t-butylacrylamide, N-dodecylacrylamide, N-octadecylacrylamide, N-diethylacrylamide, N-dibutylacrylamide and the like; etc. These other comonomers may be used singly or in combination of two or more.

In the present application, the content ratio of each of the structural unit a, the structural unit B, and the structural unit C is not particularly limited, and may be appropriately adjusted according to actual needs.

In some preferred embodiments, the ratio of the above structural unit a is preferably 80 to 98 mass%, more preferably 90 to 98 mass%, still more preferably 94 to 98 mass%, relative to the total structural units of the polymer, from the standpoint of enabling the functional particles to have a more suitable morphology and/or degree of softness and to provide a stronger binding force with the metal layer and a stronger reliability.

In some preferred embodiments, the above-mentioned ratio of the structural unit B is preferably 2 to 20% by mass, more preferably 2 to 10% by mass, still more preferably 2 to 6% by mass, relative to the total structural units of the polymer, from the viewpoint of making the functional particles have a more suitable degree of softness.

In some preferred embodiments, the mass ratio of the structural unit A to the structural unit B is preferably 80/20 to 98/2.

In some preferred embodiments, the ratio of the above structural unit C is preferably 20 mass% or less, more preferably 10 mass% or less, still more preferably 5 mass% or less, with respect to the entire structural units of the polymer.

In some preferred embodiments, the K30% hardness of the core material is preferably 500 to 2500N/mm ² More preferably 1000 to 1500N/mm ² . K30% hardness was measured by micro-durometer MCT (manufactured by Shimadzu corporation).

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

(Metal layer)

As described above, the metal layer of the functional particles of the present application coats the polymer core and is chemically bonded to the polymer. In some preferred embodiments, the surface topography formed by the metal layer is dependent on the topography of the surface of the polymer core.

In the present application, the specific composition of the metal layer is not particularly limited, and may be appropriately selected according to actual needs (e.g., functions to be conducted). In this application, the metal layer may contain a single metal or two or more metals.

In some preferred embodiments, the metal layer is a layer comprising gold, silver, copper, nickel, palladium, platinum, or any combination thereof, from the standpoint that the functional particles are capable of providing more excellent conductivity and functional stability when used in an anisotropic functional adhesive film.

(other constitution)

In addition to the polymer core and metal layers described above, the functional particles of the present application may also include other constituents to make the functional particles of the present application suitable for various application scenarios and/or to impart other functions.

In some specific embodiments, the functional particles of the present application may have magnetic particles embedded in the polymer core.

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

< fourth aspect >

The present application also provides a method for producing the functional particles described above in the < third aspect > of the present application, the method comprising: adding at least a mono (meth) acrylate monomer having an epoxy group and a monomer having two or more vinyl groups to a dispersion medium containing a surfactant to polymerize to form initial polymer particles; activating epoxy groups on the surface of the initial polymer particles with an activator to form activated polymer particles; the activated polymer particles are added to an aqueous metal compound solution and a metal layer is formed on the surface thereof with a reducing agent.

By this production method of the present application, it is possible to achieve polymerization of a mono (meth) acrylate monomer having an epoxy group and a monomer having two or more vinyl groups in various ratios to obtain initial polymer particles having high dimensional uniformity and chemical bonding of a metal layer to a polymer core material formed of the initial polymer particles, so that functional particles having strong adjustability of morphology and hardness, strong reliability of the metal layer, and uniform size can be easily obtained. In addition, the manufacturing method is environment-friendly, simple in flow and convenient for mass production.

FIG. 4 shows a specific example of a method for producing functional particles of the present application (polymer particles are formed using GMA and EDGMA as monomers, gold as metal, mercapto as an active group, sodium borohydride NaBH as a reducing agent) ₄ ). Of course, it is understood that the method of manufacturing the functional particles of the present application is not limited to the example shown in fig. 4.

The respective steps will be described in detail below.

(production of initial Polymer particles (S-c 1))

As described above, at least the mono (meth) acrylate monomer having an epoxy group and the monomer having two or more vinyl groups are added to the dispersion medium containing the surfactant to polymerize to form the initial polymer particles, as shown in step S-c1 of the example in fig. 4. An example of the initial polymer particles (using emulsion polymerization of GMA and EDGMA at 75 ℃) is shown in fig. 5.

Details of the mono (meth) acrylate monomer having an epoxy group, the monomer having two or more vinyl groups, and the other comonomer optionally participating in polymerization are as described in "< first aspect >" above, and are not described here.

In the S-c1 step, there is no particular limitation on the polymerization method used, as long as the initial polymer particles can be produced. Examples of such polymerization methods include, but are not limited to: emulsion polymerization, dispersion polymerization, precipitation polymerization, seed swelling, suspension polymerization, SPG membrane emulsification, and the like.

The dispersion polymerization method comprises two stages of polymerization nucleation and polymer particle growth, can prepare nano-scale to micron-scale particles, has uniform and adjustable particle size distribution (even compared with an emulsion polymerization method), can select a medium with low toxicity and low danger as a dispersion medium, reduces environmental pollution, and is one of the main methods for preparing the particles at present.

The emulsion polymerization method comprises four stages of initiation, primary particle formation by nuclear, secondary particle coagulation and ball growth, and has the advantages of high reaction rate, high weight average molecular weight of the product, simple post-treatment by taking water as a medium, green production, simple process and poor uniformity of particle size distribution.

The precipitation polymerization method comprises a precipitation nucleation stage and a polymer particle growth stage, wherein the polymer has uniform and clean particle size, low viscosity of a polymerization system, no surfactant or stabilizer is needed, but the yield of particles is low, and the solvent toxicity is high.

The seed swelling method firstly uses soap-free emulsion polymerization, dispersion polymerization and the like to prepare small-particle-size monodisperse polymer particles, and then uses the small-particle-size monodisperse polymer particles as seeds to swell and grow the particles, so that the seed swelling method is a good method for synthesizing micron-sized particles and is one of the main commercial methods at present.

The suspension polymerization method includes liquid-liquid dispersing period, particle growth period and particle constant period, and is to stir monomer under the action of dispersant to form one kind of dynamic balance of dispersion and aggregation in water, and the dispersion and aggregation may be used in preparing 5-1000 micron spherical particle with easy polydispersion.

The SPG film emulsifying method comprises mixing two immiscible liquids in the presence of appropriate amount of surfactant to obtain emulsion, and making hydrophobic monomer into N with SPG film ₂ Micro liquid drops are formed through micropores of the membrane under the action of pressure, so that particles with uniform particle size are prepared, and the method can be used for preparing monodisperse polymer particles with the particle size of 10-1000 mu m, but has low preparation yield and high manufacturing cost.

In some preferred embodiments, the polymerization is carried out by emulsion 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 under the action of an initiator.

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

Surfactants can be generally classified into emulsifiers known in the art and stabilizers known in the art. As the surfactant, either an emulsifier or a stabilizer may be used alone or in combination. In this step, the specific types of the emulsifier and the stabilizer to be used are not particularly limited, and may be appropriately selected depending on the type and proportion of the monomer to be polymerized, the composition of the dispersion medium, the morphology of the desired polymer core material, and the like.

Generally, examples of the emulsifier include, but are not limited to, nonionic emulsifiers such as polyoxyalkylene ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene styrenated phenyl ether, polyoxyalkylene benzylated phenyl ether, polyoxyalkylene cumyl phenyl ether, fatty acid polyglycol ether, sorbitan fatty acid ester, and the like; anionic emulsifiers such as fatty acid soaps, rosin acid soaps, alkyl sulfonates, alkylaryl sulfonates, alkyl sulfate salts, alkyl sulfosuccinates, and sulfate salts, phosphate salts, ether carboxylates, sulfosuccinates, and the like of nonionic emulsifiers having polyoxyalkylene chains; cationic emulsifiers, for example, stearyl trimethylammonium salt, cetyl trimethylammonium salt, lauryl trimethylammonium salt, dialkyl dimethylammonium salt, alkyl dimethylbenzyl ammonium salt, alkyl dimethylhydroxyethyl ammonium salt, and the like. In some preferred embodiments, the emulsifier is preferably at least one selected from the group consisting of sodium dodecyl benzene sulfonate, ammonium dodecyl benzene chloride, polyoxyethylene ether, and sodium dodecyl benzene sulfonate.

Generally, examples of stabilizers include, but are not limited to, natural polymeric stabilizers such as gelatin, agar, pectin, alginate, and the like; cellulose stabilizers such as methyl cellulose, ethyl cellulose, carboxyl cellulose, hydroxymethyl cellulose, and hydroxypropyl cellulose; such as polyvinyl alcohol, poly (meth) acrylate, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and the like. In some preferred embodiments, the stabilizer is preferably at least one selected from polyvinylpyrrolidone, polyethylene glycol, and polyvinyl alcohol.

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

The specific kind of the initiator is not particularly limited, and in some preferred embodiments, the initiator is preferably an initiator for radical polymerization. Examples of the initiator include, but are not limited to, azo-based initiators such as azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, and the like; organic peroxide initiators, for example tert-butyl peroxyneoheptanoate, tert-butyl peroxyneodecanoate, di-sec-butyl peroxydicarbonate, di-hexadecyl dicarbonate, tert-amyl peroxyneodecanoate, tert-butyl peroxypivalate, di- (4-tert-butylcyclohexyl) peroxydicarbonate, dicyclohexyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-butyl peroxydicarbonate, di- (2-ethylhexyl) peroxydicarbonate, tert-butyl peroxy2-ethylhexanoate, ditetradecyl peroxydicarbonate, tert-butyl peroxyacetate, cumene peroxyneodecanoate, di-tert-butyl peroxide, cyclohexylsulfonyl acetyl peroxide, dibenzoyl peroxide, 1, 3-tetramethylbutyl peroxyneodecanoate, di-3-methoxybutyl peroxydicarbonate, 1, 3-tetramethylbutyl peroxypivalate; persulfate initiators such as ammonium persulfate, potassium persulfate, and the like. In some preferred embodiments, the initiator is preferably at least one selected from the group consisting of ammonium persulfate, potassium persulfate, azobisisobutyronitrile, azobisisoheptonitrile.

In the S-c1 step, the ratio of the amounts of the components to each other is not particularly limited. In some preferred embodiments, the surface morphology of the initial polymer particles may be adjusted, preferably by adjusting the ratio between the emulsifier, the stabilizer, the initiator, the mono (meth) acrylate monomer with epoxy groups, the monomer with two or more vinyl groups, and the dispersion medium.

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

In the S-c1 step, there is no particular limitation on the polymerization atmosphere. In some preferred embodiments, the polymerization is carried out in an inert gas atmosphere such as nitrogen, helium, and the like.

In the step S-c1, the polymerization conditions are not particularly limited, and may be appropriately selected depending on the kind of the monomer used, and the like.

In some preferred embodiments, the polymerization temperature is preferably 50 to 120 ℃, more preferably 60 to 100 ℃.

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

In some preferred embodiments, the polymerization is performed under dynamic action. Here, examples of dynamic action include, but are not limited to, ultrasound, stirring, shaking, and the like.

In the step S-c1, the mode of adding the monomers is not particularly limited, and the monomers may be added together, or may be added in portions in any combination, or may be added dropwise continuously in any combination.

After the polymerization is completed, the initial polymer particles of the present application may be isolated (e.g., centrifuged or filtered, etc.), washed (e.g., soaked or rinsed, etc.), dried (e.g., oven dried, etc.), as desired, by means commonly used in the art.

(activation of initial Polymer particles (S-c 2))

As described above, the epoxy groups on the surface of the initial polymer particles are activated with an activator to form activated polymer particles, as shown in step S-c2 of the example of FIG. 4.

In the S-c2 step, the manner of contacting the activator with the starting polymer particles is not particularly limited. In some preferred embodiments, the initial polymer particles are dispersed in a dispersion medium, and an activator is added and reacted.

Here, examples of the dispersion medium are described in the above "(production of initial polymer particles)", and are not described here. The dispersion medium used in this step may be the same as or different from that used in the polymerization of the initial polymer particles described above. In some preferred embodiments, the dispersion medium used in the present step is preferably water from the viewpoint of reaction convenience.

In the S-c2 step, the activating group formed on the surface of the initial polymer particle by activation is not particularly limited as long as a metal can be grafted in the subsequent formation of the metal layer. In some preferred embodiments, the activating group is preferably a hydroxyl, amino, carboxyl or sulfhydryl group, more preferably a carboxyl or sulfhydryl group, yet more preferably a sulfhydryl group.

The specific type of the activator to be used is not particularly limited, and may be appropriately selected depending on the type of the activating group to be obtained. Examples of active agents include, but are not limited to, ozone (O) ₃ ) The method comprises the steps of carrying out a first treatment on the surface of the Such as hydrogen sulfide (H) ₂ S), weak acids such as acetic acid, oxalic acid, hypochlorous acid and the like; such as sulfuric acid, nitric acid, hydrochloric acid, and the like. In some preferred embodiments, the activator is preferably selected from ozone (O ₃ ) Hydrogen sulfide (H) ₂ S), acetic acid, oxalic acid, sulfuric acid, nitric acid,

Additionally, in some preferred embodiments, the mass ratio of the activator to the initial polymer particles is preferably from 1:50 to 1:200, more preferably from 1:50 to 1:150, still more preferably from 1:50 to 1:100.

In the step S-c2, the activation reaction conditions are not particularly limited, and may be appropriately selected depending on the activator and the like used.

In some preferred embodiments, the reaction temperature is preferably 40-60 ℃.

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

In some preferred embodiments, the activation reaction is performed under dynamic action. Here, examples of dynamic action include, but are not limited to, ultrasound, stirring, shaking, and the like.

After the reaction is completed, the activated polymer particles of the present application may be separated (e.g., centrifuged or filtered, etc.), washed (e.g., soaked or rinsed, etc.), dried (e.g., oven dried, etc.), as desired, by means commonly used in the art.

(construction of Metal layer (S-c 3))

As described above, the resulting activated polymer particles are added to an aqueous metal compound solution and a metal layer is formed on the surface thereof with a reducing agent. Specifically, the activating groups present on the surface of the activated polymer particles may react with the metal ions reduced by the reducing agent in the aqueous metal compound solution to produce a firm metal layer. As shown in step S-c3 of the example in fig. 4.

In this step, the metal compound to be used is not particularly limited, and may be appropriately selected according to the kind of the metal layer to be formed and the kind of the activating group. In some preferred embodiments, 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, chloroplatinic acid from the viewpoint of more effectively forming the metal layer.

In the S-c3 step, the reducing agent may be one commonly used in the art, for example, sodium borohydride, hydrazine hydrate, and the like.

In the step S-c3, the amounts of the metal compound and the reducing agent are not particularly limited, and may be appropriately adjusted depending on the type of the activating group, the type of the metal compound, the type of the reducing agent, and the like.

In the step S-c3, the reaction conditions for the metal layer formation reaction are not particularly limited, and may be appropriately selected depending on the type of the activating group, the type of the metal compound, the type of the reducing agent, and the like.

After the reaction is completed, the functional particles of the present application may be separated (e.g., centrifuged or filtered, etc.), washed (e.g., soaked or rinsed, etc.), dried (e.g., oven dried, etc.), as desired, by means commonly used in the art.

(other steps)

In addition to the above steps, the method for producing functional particles of the present application may include other steps depending on the composition of the functional particles finally obtained.

In some specific embodiments, the non-conductive inorganic particles are deposited, coated with a resin and/or elastomer, plated with a metal, and the like.

(specific examples)

In some particularly preferred embodiments, the functional particles of the present application are obtained by the following method:

adding an emulsifying agent, a stabilizing agent and a dispersing medium into a reaction kettle, stirring thoroughly, flushing nitrogen, then raising the temperature to 60 ℃, adding a mixed solution of an initiator, a mono (methyl) acrylic ester monomer with epoxy groups, a monomer with more than two vinyl groups and the dispersing medium into the reaction solution, and continuing to react for 1 hour after the dripping is finished. And then, obtaining the initial polymer particles with the surfaces containing epoxy groups through centrifugation and washing.

Adding initial polymer particles into water, adding an activating agent, wherein the mass ratio of the activating agent to the polymer particles is 1:50-200, stirring and reacting for 30-120 min at the reaction temperature of 40-60 ℃, and centrifugally washing to obtain polymer particles with carboxyl or sulfhydryl groups on the surfaces;

the prepared activated polymer particles with a large number of active functional groups on the surfaces are added into a metal compound aqueous solution, then a reducing agent is added, and the mixture is stirred for 30 to 120 minutes at the temperature of 40 to 60 ℃ to obtain the functional particles with the metal layers on the surfaces.

< fifth aspect >

The present application provides a functional particle obtained by a manufacturing method comprising: adding at least a mono (meth) acrylate monomer having an epoxy group and a monomer having two or more vinyl groups to a dispersion medium containing a surfactant to polymerize to form initial polymer particles (production of initial polymer particles (S-d 1)); activating epoxy groups on the surface of the initial polymer particles with an activator to form activated polymer particles (activation of initial polymer particles (S-d 2)); the activated polymer particles are added to an aqueous metal compound solution and a metal layer is formed on the surface thereof with a reducing agent (construction of a metal layer (S-d 3)).

In this case, the functional particles of the present application are obtained by a specific method, enabling polymerization of a mono (meth) acrylate monomer having an epoxy group and a monomer having two or more vinyl groups in various ratios to form an initial polymer particle and chemical bonding of a metal layer to a polymer core formed of the initial polymer particle. The molecular chain structure of the polymer core material of the functional particle is flexible and adjustable, and the binding force between the functional particle and the metal layer is strong, so that the functional particle can have the expected morphology and hardness degree according to the requirement, the metal layer is not easy to fall off, and the reliability is strong; while the functional particles are of uniform size. Therefore, the functional particles are particularly suitable for being contained in the anisotropic functional adhesive film as functional particles, so that the anisotropic functional adhesive film can have excellent conductivity, precision and functional stability and is suitable for different application scenes.

In the above step S-d1, as described above, the initial polymer particles are formed so as to serve as a basis for the polymer core of the functional particles.

In the above step S-d2, as described above, the epoxy groups on the surface of the starting polymer particles are activated, and the activated groups on the formed activated polymer particles are used for binding metals in a later step.

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

Details of the steps S-d1, S-d2, S-d3 (including preferred embodiments) are the same as those of the steps S-c1, S-c2, S-c3 in the method for producing functional particles described in the above < fourth aspect >, respectively, and are not described in detail here.

In addition to the steps S-d1, S-d2, and S-d3 described above, the method for producing functional particles according to the present aspect may include other steps depending on the composition of the functional particles finally obtained.

The functional particles of the present aspect comprise a core material and a metal layer coating the core material. The core material is formed of a polymer containing a unit based on a mono (meth) acrylate monomer having an epoxy group and a unit based on a monomer having two or more vinyl groups; the metal in the metal layer is chemically bonded to the polymer. The details of the functional particles of this aspect are the same as those described in the above < third aspect >, and are not described here again.

< sixth aspect >

The present application also provides an anisotropic functional adhesive film which is a film-like adhesive material comprising an adhesive and the above functional particles in < third aspect > or < fifth aspect > of the present application.

The anisotropic functional adhesive film has the advantages that the anisotropic functional adhesive film contains the functional particles with strong shape and hardness degree adjustability, strong metal layer reliability and uniform size, and the anisotropic functional adhesive film can have excellent conductivity, precision and functional stability no matter how the functional particles are arranged, and is suitable for different application scenes.

In the present application, the arrangement of the functional particles in the anisotropic functional film is not particularly limited, and may be appropriately selected according to actual needs.

In some specific embodiments, from the standpoint that the anisotropic functional adhesive film of the present application can be formed more easily, it is preferable that the functional particles are randomly dispersed in the adhesive. In this case, the anisotropic functional adhesive film of the present application may be obtained by a method well known in the art, for example, mixing a material for forming an adhesive with functional particles, and then coating on a substrate and drying, however, it is understood that the forming method is not limited thereto.

In other specific embodiments, the functional particles are distributed in such a manner that projections on at least one plane of the adhesive film formed by the first direction and the second direction are separated from each other from the viewpoint of being better capable of combining excellent conductivity, precision and functional stability and being suitable for different application scenarios.

Here, there is no particular limitation on the angles of the first direction and the second direction, and both of them. In some preferred embodiments, the first direction and the second direction are preferably perpendicular to each other. In other preferred embodiments, a plane defined 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.

In this case, the anisotropic functional adhesive film of the present application can be obtained by a method well known in the art. In some preferred embodiments, the projections of the functional particles onto at least one plane formed by the first direction and the second direction are preferably at a distance from each other of more than 0 μm and less than 25 μm, more preferably 0 μm to 9 μm, still more preferably 2 μm to 6 μm.

Furthermore, in other preferred embodiments, the anisotropic functional adhesive film of the present application can be obtained by the method described in the above < second aspect >. In this case, for convenience purposes, the term "Z direction" means a direction perpendicular to the film or the surface of the substrate carrying the film (i.e., the thickness direction), the term "X direction" means a direction corresponding to the transverse direction of the substrate carrying the film (sometimes also referred to as the width direction, i.e., the TD direction), the term "Y direction" means a direction corresponding to the longitudinal direction of the substrate carrying the film (sometimes also referred to as the mechanical direction, i.e., the MD direction), and the term "XY direction" means a direction parallel to the film or the surface of the substrate carrying the film (i.e., the plane direction), wherein the term "surface of the film" is generally understood to be that surface of the substrate carrying the film that contacts the film during the fabrication of the film.

In some preferred embodiments, the thickness of the anisotropic functional adhesive film is preferably 10-50 μm. In addition, in some preferred embodiments, the thickness of the anisotropic functional adhesive film is preferably 3 to 15 times the average particle diameter of the functional particles from the viewpoint that the anisotropic functional adhesive film better ensures excellent conductivity, precision, and functional stability.

In this application, in some preferred embodiments, the total mass of the functional particles is preferably 1 to 15 mass%, more preferably 1 to 10 mass%, still more preferably 2 to 8 mass%, relative to the total mass of the binder in the adhesive film.

In the present application, the form of the anisotropic functional adhesive film is not particularly limited, and may be in the form of an adhesive film without a base material, or may be in the form of an adhesive film carried on a base material (for example, a base material for carrying an adhesive film used in a manufacturing process).

The components will be described in detail below.

(functional particles)

The details of the functional particles of the present application have been described in "< third aspect > or < fifth aspect >" above, and are not described here again.

(adhesive)

In the present application, the specific kind of the adhesive is not particularly limited, and various adhesives commonly used in the art for forming an anisotropic functional adhesive film may be employed.

In some preferred embodiments herein, the adhesive is preferably thermosetting, examples of which include, but are not limited to, epoxy-based adhesives, (meth) acrylic-based adhesives, isocyanate-based adhesives, silicone-based adhesives, polyurethane-based adhesives, and the like.

In the present application, where the adhesive in the anisotropic functional adhesive film comprises a thermosetting adhesive, the thermosetting adhesive is preferably uncured, and may be cured before or during use of the adhesive film as desired.

In some more 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 binders are the same as in the arrangement method of the particles described in the above < first aspect >.

(other Components)

The anisotropic functional adhesive film of the present application may contain other components as needed in addition to the adhesive and the functional particles within a range not to impair the technical effects of the present application. Examples of such other components include, but are not limited to, inorganic and/or organic particles other than the functional particles of the present application (which optionally have conductivity to electricity, heat, magnetism), various tackifying resins, crosslinking accelerators, silane coupling agents, anti-aging agents, colorants (e.g., pigments or dyes), ultraviolet absorbers, antioxidants, chain transfer agents, plasticizers, softeners, antistatic agents, fibers, and the like. These other components may be used singly or in combination of two or more.

(application scenario)

In the application, the application area of the anisotropic functional adhesive film is very wide, and the anisotropic functional adhesive film can endow a plurality of devices with anisotropic performance, for example, as the anisotropic conductive adhesive, the anisotropic functional adhesive film can be used for electrically interconnecting an IC, an FPC/COF and the like with a display device in a terminal product; the anisotropic magnetic conductive adhesive can be used for signal transmission and prevent signal crosstalk; as anisotropic heat-conducting adhesive, a good heat-dissipating effect can be formed on a chip or a device module.

Taking anisotropic conductive adhesive as an example, its system architecture and scenario are described below, as an example, specifically shown in fig. 7.

The anisotropic conductive adhesive is stuck on the conductive convex points of the substrate, and then after the other device linking components are stuck on the alignment, the anisotropic adhesive film is softened (in a colloid state) after being pressurized and heated, and conductive particles can flow and be uniformly distributed, so that each circuit has a certain number of conductive particles, and a stable resistance value is ensured. Under the action of adhesive pressure, the insulating film of the conductive particles is broken, a plurality of pressed and deformed conductive particles are clamped between the convex points on the wafer and the ITO circuits on the glass substrate corresponding to the convex points, the deformed conductive particles realize the electric interconnection between the upper convex points and the lower convex points, and particles in other areas without being pressed are not contacted with each other, so that the anisotropic interconnection in the insulation Z direction in the XY direction is realized.

< example >

The embodiments of the present application are described in detail below, but the present application is not limited to the following embodiments.

Embodiment one: preparation of anisotropic conductive adhesive film

(1) Preparation of conductive particles

(S-c 1) preparation of initial Polymer particles:

adding an emulsifying agent, a stabilizing agent and a dispersing medium into a reaction kettle, stirring thoroughly, then flushing nitrogen, raising the temperature to 60 ℃, adding a mixed solution of an initiator, glycidyl methacrylate, trimethylolpropane tetraacrylate and the dispersing medium into the reaction solution, and continuing to react for 1 hour after the dripping is finished. And then, obtaining the initial polymer particles with the surfaces containing epoxy groups through centrifugation and washing.

Wherein the emulsifier is sodium dodecyl benzene sulfonate, the stabilizer is polyvinylpyrrolidone, the dispersion medium is ethanol, and the initiator is ammonium persulfate. The mass ratio of the sodium dodecyl benzene sulfonate, the polyvinylpyrrolidone, the ammonium persulfate, the glycidyl methacrylate, the trimethylolpropane tetraacrylate and the ethanol is as follows: 1:1:0.1:50:10:100.

(S-c 2) activation of initial Polymer particles:

adding initial polymer particles into water, adding an activating agent, wherein the mass ratio of the activating agent to the initial polymer particles is 1:50, stirring and reacting for 30min at the reaction temperature of 40 ℃, and centrifugally washing to obtain activated polymer particles with carboxyl on the surfaces; wherein the activator is O ₃ 。

(S-c 3) constructing a metal layer on the surface of the activated polymer particles:

dispersing the surface-activated polymer particles in water, adding sodium borohydride, then dropwise adding chloroauric acid tetrahydrate solution, and reacting for 30min under stirring; wherein, the mass ratio of the polymer particles to the water to the sodium borohydride to the chloroauric tetrahydrate is 1:50:0.2:0.1, and the functional particles with gold grafted on the surfaces can be obtained and then centrifugally washed;

the reactions involved are: 8HAuCl ₄ ·4H ₂ O+3NaBH ₄ →8Au+3H ₃ BO ₃ +29HCl+3NaCl+23H ₂ O

Wherein HAuCl ₄ ·4H ₂ O is chloroauric acid tetrahydrate, naBH ₄ Sodium borohydride, au is gold particles, H ₃ BO ₃ Is boric acid.

(2) Solvent-based epoxy resin adhesive coating liquid preparation:

and (3) mixing the solid epoxy resin, the liquid epoxy resin, the latent curing agent, the toughening agent and the solvent according to the weight ratio of 1:1:0.05:0.1:3, and uniformly stirring to obtain the solvent type epoxy resin adhesive coating liquid.

Wherein the solid epoxy resin is solid phenolic epoxy resin with weight average molecular weight of about 12000, the liquid epoxy resin is bisphenol A epoxy resin, the latent curing agent is dimethyl imidazole, the toughening agent is core-shell polymer plasticizer, and the solvent is methylene dichloride.

(3) Preparation of an anisotropic conductive adhesive film:

(S-b 1) arrangement of functional particles

Dispersing functional particles in tetrahydrofuran, adding the solvent-based epoxy resin adhesive coating liquid, stirring uniformly, coating the mixture on a PET film (wherein the mass ratio of the polymer particles to the epoxy resin in the solvent-based epoxy resin adhesive coating liquid is 1:5:1), baking at 40 ℃, drying the solvent, and then entering a film drawing stage, wherein the stretching multiple in the X direction is 1, the stretching multiple in the Y direction is 1, and the stretching in the XY direction is 10 degrees (stretching is symmetrically performed at 10 degrees relative to the X direction and is synonymous as shown in figure 3). The anisotropic conductive paste was controllably adjusted in such a manner that the projection distance between the finally obtained particles in the XY direction was 1 μm.

In the substrate subjected to biaxial stretching, the degree of orientation in the X direction was 1.8, the degree of orientation in the Y direction was 3.0, the ratio of the degree of orientation in the X direction to the degree of orientation in the Y direction was 1.7, and the orientation angle with respect to the X direction was 45 °.

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

(S-b 2) formation of Anisotropic conductive film

And (2) coating a layer of the solvent type epoxy resin adhesive coating liquid on the arranged functional particle initial adhesive film prepared in the step (S-b 1), baking at 40 ℃, and fusing the solvent type epoxy resin adhesive coating liquid with the initial adhesive film prepared in the step (S-b 1) into a whole after solvent drying, so that the anisotropic conductive adhesive film with the total thickness of 10 mu m can be obtained.

The prepared anisotropic conductive adhesive film with the size of 2mm multiplied by 19mm is stuck on a glass substrate of an IZO circuit at the temperature of 80 ℃ and the pressure of 0.98MPa, the diaphragm is peeled off, the bump of the chip and the glass substrate with the IZO circuit are positioned, heating or hot pressing is carried out from the upper part of the chip at the temperature of 160 ℃, formal connection is carried out, and the electrical property test is carried out. As a result, the average value of on-resistance is less than 2Ω, and the insulation resistance is greater than or equal to 10 ⁹ The proportion of Ω is 100%.

Embodiment two: preparation of an anisotropic magnetic conductive adhesive film:

(1)magnetic conductionPreparation of sexual granules

(S-c 1) preparation of initial Polymer particles: adding an emulsifier, a stabilizer and a dispersion medium into a reaction kettle, stirring thoroughly, then flushing nitrogen, raising the temperature to 100 ℃, adding a mixed solution of an initiator, glycidyl methacrylate, trimethylolpropane trimethacrylate and the dispersion medium into the reaction solution, and continuing to react for 3 hours after the dripping is finished. And then, obtaining the initial polymer particles with the surfaces containing epoxy groups through centrifugation and washing.

The emulsifier is sodium dodecyl benzene sulfonate, the stabilizer is polyvinyl alcohol, the initiator is ammonium persulfate, and the dispersion medium is isopropanol. Wherein, the mass ratio of the sodium dodecyl benzene sulfonate, the polyvinyl alcohol, the ammonium persulfate, the glycidyl methacrylate, the trimethylolpropane trimethacrylate and the isopropanol is as follows: 1:2:1:100:20:200.

(S-c 2) activation of initial Polymer particles:

the method comprises the steps of adding initial polymer particles into water, adding an activating agent, wherein the mass ratio of the activating agent to the initial polymer particles is 1:200, stirring and reacting for 120min at the reaction temperature of 60 ℃, and centrifugally washing to obtain activated polymer particles with mercapto on the surfaces; wherein the activator is H ₂ S。

dispersing the surface-activated polymer particles in water, adding hydrazine hydrate, then dropwise adding silver nitrate solution, and reacting for 50min while stirring; wherein the proportion of the activated polymer particles, water, hydrazine hydrate and silver nitrate is 1:200:5:5, and the functional particles with silver plated surfaces can be obtained and then centrifugally washed.

(2) Solvent-based epoxy resin adhesive coating liquid preparation:

and (3) mixing the solid epoxy resin, the liquid epoxy resin, the latent curing agent, the toughening agent and the solvent according to the weight ratio of 1:5:0.2:0.1:10, and uniformly stirring to obtain the solvent type epoxy resin adhesive coating liquid.

Wherein the solid epoxy resin is bisphenol solid epoxy resin, the liquid epoxy resin is bisphenol F epoxy resin 862, and the latent curing agent is boron trifluoride and ethylamine complex thereof; the toughening agent is a core-shell plasticizer, and the solvent is dioxane.

(3) Preparing an anisotropic magnetic conductive adhesive film:

(S-b 1) arrangement of functional particles

Dispersing functional particles in cyclohexanone, adding solvent-based epoxy resin adhesive coating liquid, uniformly stirring, and coating onto a PET film, wherein the mass ratio of the polymer particles to the epoxy resin in the solvent-based epoxy resin adhesive coating liquid is 1:20:5, baking at 60 ℃, drying the solvent, entering a film drawing stage, wherein the stretching multiple in the X direction is 5, the stretching multiple in the Y direction is 5, and the stretching in the XY direction is 60 degrees. The projection distance between the particles in the XY direction was controlled to be 5. Mu.m.

In the substrate subjected to biaxial stretching, the degree of orientation in the X direction was 3.2, the degree of orientation in the Y direction was 6.8, the ratio of the degree of orientation in the X direction to the degree of orientation in the Y direction was 2.1, and the orientation angle with respect to the X direction was 30 °.

(S-b 2) formation of Anisotropic magnetic conductive film

And (3) coating a layer of the solvent type epoxy resin adhesive coating liquid on the arranged functional particle initial adhesive film prepared in the step (S-b 1), baking at 60 ℃, and fusing the solvent type epoxy resin adhesive coating liquid with the initial adhesive film prepared in the step (S-b 1) into a whole after the solvent is dried, so that the anisotropic magnetic adhesive film with the total thickness of 50 mu m can be obtained.

For the anisotropic magnetic conductive adhesive film, an Agilent radio frequency network/frequency spectrum/impedance analyzer 4396B and a magnetic material test fixture 16454A are adopted to test that the magnetic permeability in the Z direction is more than or equal to 200 and the magnetic permeability in the XY direction is less than or equal to 5.

Embodiment III:an anisotropic heat-conducting adhesive mainly comprises the following steps:

(1) Guide railHeat of the bodyPreparation of sexual granules

(S-c 1) preparation of initial Polymer particles:

adding an emulsifier, a stabilizer and a dispersion medium into a reaction kettle, stirring thoroughly, then flushing nitrogen, raising the temperature to 80 ℃, adding an initiator into the reaction solution, adding a mixed solution of glycidyl methacrylate, triethylene glycol diacrylate and the dispersion medium, and continuing to react for 2 hours after the dripping is finished. And then, obtaining the initial polymer particles with the surfaces containing epoxy groups through centrifugation and washing.

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

(S-c 2) activation of initial Polymer particles:

The method comprises the steps of adding initial polymer particles into water, adding an activating agent, wherein the mass ratio of the activating agent to the polymer particles is 1:100, stirring and reacting for 80min at the reaction temperature of 50 ℃, and centrifugally washing to obtain activated polymer particles with carboxyl on the surfaces; wherein the activator is acetic acid.

dispersing the surface-activated polymer particles in water, adding sodium borohydride, then dropwise adding copper sulfate solution, and reacting for 40min while stirring; wherein the ratio of the polymer particles to water to sodium borohydride to copper sulfate is 1:100:2:2, so that functional particles with copper plated on the surface can be obtained, and the functional particles are centrifugally washed.

(2) Solvent-based (meth) acrylic resin-based adhesive preparation:

blending (methyl) acrylic resin, a cross-linking agent, a thermal initiator, a toughening agent, a polymerization inhibitor and a solvent according to the weight ratio of 1:0.5:0.2:0.5:0.1:10, and uniformly stirring to obtain solvent type (methyl) acrylic resin adhesive coating liquid.

Wherein the (methyl) acrylic resin is polyurethane modified (methyl) acrylic resin, the cross-linking agent is dipentaerythritol hexaacrylate, the initiator is diisobutyryl peroxide, and the polymerization inhibitor is diethyl hydroxylamine.

(3) Preparing an anisotropic heat conduction adhesive film:

(S-b 1) arrangement of functional particles

Dispersing the functional particles with gold plating on the surface in ethylene oxide, adding solvent type (methyl) acrylic resin adhesive coating liquid, uniformly stirring, and coating on a PET film, wherein the mass ratio of the functional particles to the ethylene oxide to the (methyl) acrylic resin contained in the solvent type (methyl) acrylic resin adhesive coating liquid is 1:15:3, after baking at 50 ℃, the solvent is dried, the film drawing stage is carried out, the X-direction stretching multiple is 4, the Y-direction stretching multiple is 10, and the XY direction is subjected to 30-degree angle stretching. The projection distance between the particles in the XY direction was controlled to be 4. Mu.m.

In the substrate subjected to biaxial stretching, the degree of orientation in the X direction was 2.8, the degree of orientation in the Y direction was 7.3, the ratio of the degree of orientation in the X direction to the degree of orientation in the Y direction was 2.6, and the orientation angle with respect to the X direction was 80 °.

(S-b 2) formation of Anisotropic Heat conductive film

A layer of solvent type (methyl) acrylic resin type adhesive coating liquid is coated on the arranged functional particle initial adhesive film prepared in the step (S-b 1), and after baking at 40 ℃, the solvent is dried and then is integrated with the initial adhesive film prepared in the step (S-b 1), so that the anisotropic heat-conducting adhesive film with the overall thickness of 30 mu m can be obtained.

For the anisotropic heat conduction adhesive film, a heat conduction coefficient in the Z direction is measured to be 105 w/(m.k) by adopting a heat conduction coefficient measuring instrument, and the heat conduction coefficient in the XY direction is smaller than 20 w/(m.k). Therefore, by introducing particles with high heat conduction and copper-containing surfaces, heat conduction in the Z direction is realized, and heat conduction in the XY direction is not realized, so that a good anisotropic heat conduction effect is realized.

The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of apparatus, systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.

It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by hardware (e.g., circuits or ASICs (Application Specific Integrated Circuit, application specific integrated circuits)) which perform the corresponding functions or acts, or combinations of hardware and software, such as firmware, etc.

Although the invention is described herein in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The embodiments of the present application have been described above, the foregoing description is exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method of aligning particles, the method comprising:

2. The method of claim 1, wherein the first direction and the second direction are perpendicular to each other in a plane in which they are formed.

3. The method according to claim 1 or 2, wherein a plane formed by the first direction and the second direction is parallel to the surface of the substrate.

4. A method of aligning particles according to any one of claims 1 to 3, wherein 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 to 9.9.

5. The method according to any one of claims 1 to 4, wherein 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.

6. The method according to any one of claims 1 to 5, wherein 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.

7. The method according to any one of claims 1 to 6, wherein the biaxially stretched substrate has an orientation angle of 0 to 90 ° with respect to the transverse direction.

8. The method according to any one of claims 1 to 7, wherein the first direction is a transverse direction of the base material, and the second direction is a longitudinal direction of the base material.

9. The method of arranging particles according to any one of claims 1 to 8, wherein the composite structure is formed by: an adhesive coating liquid that does not contain the particles is coated on the extensible substrate and dried to form an adhesive layer, and the particles are further covered on the adhesive layer in such a manner that at least a part thereof is embedded in the adhesive layer.

10. The method of arranging particles according to any one of claims 1 to 8, wherein the composite structure is formed by: an adhesive coating liquid comprising the particles is coated on the extensible substrate and dried.

11. The method according to any one of claims 1 to 10, wherein the extensible base material is at least one selected from the group consisting of polyethylene terephthalate resin, polybutylene terephthalate resin, polycarbonate resin, polypropylene resin, and polymethyl methacrylate resin.

12. The method of arranging particles according to any one of claims 1 to 11, wherein the particles are functional particles comprising a core material and a metal layer coating the core material;

13. The method according to any one of claims 1 to 12, wherein the binder resin contained in the binder layer is a thermosetting epoxy resin or a thermosetting (meth) acrylic resin.

14. The method of arranging particles according to any one of claims 1 to 13, wherein a thickness of the adhesive layer is 1/6 to 1/1 of an average particle diameter of the particles before the biaxial stretching is performed.

15. The method of arranging particles according to any one of claims 1 to 14, wherein the thickness tolerance of the adhesive layer is less than 0.05 μm before the biaxial stretching is performed.

16. The method according to any one of claims 1 to 15, wherein the biaxial stretching is performed at a stretching ratio of 1 to 20 times and a stretching speed of 2 to 40mm/min.

17. The method according to any one of claims 1 to 16, wherein projections of the particles on at least one plane of the substrate formed by the first direction and the second direction after the biaxial stretching are spaced from each other by a distance of more than 0 μm and 25 μm or less.

18. A method for manufacturing an anisotropic functional adhesive film, the method comprising:

aligning functional particles having functional conductivity to form a stretched composite structure on a substrate using the alignment method of particles according to any one of claims 1 to 17;

another adhesive layer is formed on the stretched composite structure.

19. A functional particle, characterized in that the functional particle comprises a core material and a metal layer coating the core material;

20. The functional particles of claim 19, wherein the functional particles have an average particle size of 1 to 15 μm.

21. The functional particle of claim 19 or 20, having a roughened surface.

22. The functional particle of claim 21, wherein the roughened surface has a roughened structure formed from a plurality of burr structures.

23. The functional particles of any one of claims 19 to 22, wherein the core material has a k30% hardness of 500 to 2500N/mm ² 。

24. The functional particles of any one of claims 19-23 wherein the polymer has a degree of crosslinking of 0.5% to 20%.

25. Functional particle according to any one of claims 19 to 24, characterized in that the ratio of units based on mono (meth) acrylate monomers bearing epoxy groups is 80 to 98 mass% relative to the total structural units of the polymer.

26. Functional particle according to any one of claims 19 to 25, characterized in that the ratio of units based on monomers bearing more than two vinyl groups is 2 to 20 mass% relative to the total structural units of the polymer.

27. The functional particle of any one of claims 19-26, wherein the metal layer is a layer comprising at least one of gold, silver, copper, nickel, palladium, and platinum.

28. A method of manufacturing a functional particle according to any one of claims 19 to 27, wherein the method comprises:

29. The method of claim 28, wherein the mass ratio of the activator to the initial polymer particles is from 1:50 to 1:200.

30. The method for producing functional particles according to claim 28 or 29, wherein the activator is at least one selected from ozone, hydrogen sulfide, acetic acid, oxalic acid, sulfuric acid, nitric acid, and hydrochloric acid.

31. The method for producing functional particles according to any one of claims 28 to 30, wherein 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.

32. Functional particles, characterized in that they are obtained by a manufacturing process comprising:

33. An anisotropic functional adhesive film, characterized in that it is a film-like adhesive material comprising an adhesive and functional particles according to any one of claims 19-27 or functional particles according to claim 32.

34. The anisotropic functional adhesive film of claim 33, wherein the functional particles are randomly dispersed in the adhesive.

35. The anisotropic functional adhesive film according to claim 33, wherein the functional particles are distributed in such a manner that projections on at least one plane of the adhesive film formed by the first direction and the second direction are separated from each other.

36. The anisotropic functional adhesive film according to claim 35, wherein the functional particles have a distance of more than 0 μm and 25 μm or less between each other projected at least on one plane of the adhesive film formed by the first direction and the second direction.

37. The anisotropic functional film according to any of claims 33 to 36, wherein the total mass of the functional particles is 1 to 15 mass% with respect to the total mass of the adhesive.

38. The anisotropic functional adhesive film according to any of claims 33 to 37, wherein the adhesive resin contained in the anisotropic functional adhesive film is a thermosetting epoxy resin or a thermosetting (meth) acrylic resin.