WO2019033722A1

WO2019033722A1 - Conductive layer of electromagnetic shielding coating, electromagnetic shielding coating and preparation method therefor

Info

Publication number: WO2019033722A1
Application number: PCT/CN2018/075982
Authority: WO
Inventors: 闫勇; 高小君
Original assignee: 苏州城邦达力材料科技有限公司
Priority date: 2017-08-16
Filing date: 2018-02-09
Publication date: 2019-02-21
Also published as: KR20190001141U; CN207070595U

Abstract

An embodiment of the present invention provides a conductive layer of an electromagnetic shielding coating, an electromagnetic shielding coating and a preparation method therefor, pertaining to the field of electromagnetic shielding technology. The conductive layer of an electromagnetic shielding coating comprises a first conductive layer and a second conductive layer coated on one side of the first conductive layer; a conductive powder of the first conductive layer comprises a dendritic conductive powder, wherein the particle size of conductive particles in the dendritic conductive powder is 5-20 µm a conductive powder of the second conductive layer comprises a flaky conductive powder or a spherical conductive powder, wherein the particle size of conductive particles in the flaky conductive powder or the spherical conductive powder is the same as the thickness of the second conductive layer. The embodiment resolves a technical issue of the prior art in which attempts to improve the appearance of rough and uneven conductive layers of an electromagnetic shielding coating often lead to increased costs or lower conductive and shielding capabilities. Providing the second conductive layer compensates for the rough and uneven first conductive layer, and enables the conductive layer of the entire electromagnetic shielding coating to have a better shielding effect.

Description

Conductive layer of electromagnetic shielding film, electromagnetic shielding film and preparation method thereof

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. 2017210230742, entitled "Electromagnetic Shielding Electromagnetic Layer and Electromagnetic Shielding Film", filed on August 16, 2017, the entire contents of which are incorporated herein by reference. In the application.

Technical field

The present invention relates to the field of electromagnetic shielding technology, and in particular to a conductive layer of an electromagnetic shielding film and an electromagnetic shielding film.

Background technique

Electromagnetic shielding is widely used in communications, electronic products, network hardware, medical instruments, aerospace and defense. In communication, electromagnetic shielding is the separation of metal between two spatial regions to control electric, magnetic and electromagnetic waves. The induction and radiation of the area to another area. Specifically, the shield is used to surround the components, circuits, assemblies, cables, or interference sources of the entire system to prevent interference electromagnetic fields from spreading outward, or to surround the receiving circuits, devices, or systems with shields to prevent them. The electromagnetic shielding film is a commonly used shielding body under the influence of external electromagnetic fields.

The coating machine is mainly used for the surface coating process of film, paper, etc. It is a machine for coating a roll of substrate with a special function of glue, paint or ink, and then winding and storing it after drying. . The coating machine adopts a special multi-functional coating head, which can realize various forms of surface coating production. Since the development of the coating machine, laser transfer, bronzing, optical film, protective film, electronic film and dielectric exchange film have been realized. Coating process.

The coating production process of the existing electromagnetic shielding film is mainly to apply an insulating layer on the carrier film, and after drying and hardening the surface of the insulating layer, according to actual needs, the metal layer is processed on the outer side of the insulating layer to form a semi-finished product, and The outer side of the semi-finished product is coated with a conductive layer glue. Usually, the thickness of the conductive layer is 5-15 um. Finally, a protective film is attached on the outer side of the conductive layer to obtain an electromagnetic shielding film. In the manufacturing process of the electromagnetic shielding film, the shielding performance and the flatness of the electromagnetic shielding film often fail to balance.

Summary of the invention

The object of the embodiments of the present invention includes providing a conductive layer of an electromagnetic shielding film and an electromagnetic shielding film to solve the technical problems existing in the prior art.

The conductive layer of the electromagnetic shielding film provided by the embodiment of the present invention includes a first conductive layer and a second conductive layer coated on one side of the first conductive layer;

The conductive powder of the first conductive layer comprises a dendritic conductive powder, and the conductive particles of the dendritic conductive powder have a particle diameter of 5-20 um;

The conductive powder of the second conductive layer comprises a sheet-like conductive powder or a spherical conductive powder, and the particle diameter of the conductive particles of the sheet-like conductive powder or the spherical conductive powder is the same as the thickness of the second conductive layer.

Further, the first conductive layer has a thickness of 5-10 um.

Further, the conductive particles of the sheet-like conductive powder or the spherical conductive powder have a particle diameter of 1-3 um, and the second conductive layer has a thickness of 1-3 um.

Further, the dendritic conductive powder has a powder content of 30-40% in the first conductive layer.

Further, the conductive particles of the first conductive layer and the second conductive layer comprise one or more of silver, copper, iron, nickel, zinc, a silver alloy, a copper alloy, an iron alloy, a nickel alloy, and a zinc alloy. .

Further, the material of the first conductive layer comprises a thermosetting epoxy resin, an acrylic resin or a polyurethane.

Further, the material of the second conductive layer comprises a thermosetting epoxy resin, an acrylic resin or a polyurethane. Further, a side of the first conductive layer away from the second conductive layer is further coated with a third conductive layer, and the third conductive layer includes a metal layer and/or a graphene layer.

Further, the conductive powder of the second conductive layer (200) includes at least one of a sheet-like conductive powder and a spherical conductive powder.

The present invention also provides an electromagnetic shielding film comprising the conductive layer of the electromagnetic shielding film according to any one of the above aspects.

Further, the carrier film, the insulating layer and the protective film are further included;

The insulating layer is coated on one side of the carrier film, the first conductive layer is coated on a side of the insulating layer facing away from the carrier film, and the protective film is attached to the second conductive layer to face away from One side of the first conductive layer is disposed.

Further, the material of the insulating layer comprises a thermosetting epoxy resin, an acrylic resin or a polyurethane glue.

Further, the material of the protective film comprises a release film or a release paper.

Further, a metal layer or a graphene layer is further disposed between the insulating layer and the conductive layer of the electromagnetic shielding film.

The embodiment of the invention further provides a method for preparing an electromagnetic shielding film, comprising:

Providing a carrier film;

Forming a first conductive layer on one side of the carrier film, and the conductive powder of the first conductive layer comprises a dendritic conductive powder;

A second conductive layer is formed on a side of the first conductive layer away from the insulating layer, and the conductive powder of the second conductive layer (200) comprises a sheet-like conductive powder or a spherical conductive powder.

Further, before the step of forming the first conductive layer, the method further includes:

An insulating material is coated on one side of the carrier film to form an insulating layer, and the first conductive layer is disposed on a side of the insulating layer away from the carrier film.

Further, after the step of forming the insulating layer, the method further includes:

A metal layer or a graphene layer is formed on a side of the insulating layer away from the carrier film to form a third conductive layer.

Further, after the step of forming the second conductive layer, the method further includes:

A protective film is attached to a side of the second conductive layer away from the first conductive layer.

The conductive layer of the electromagnetic shielding film provided by the embodiment of the invention includes a first conductive layer and a second conductive layer, and the second conductive layer is coated on one side of the first conductive layer, and the electromagnetic shielding film is improved by using two conductive layers. The appearance of the conductive layer is rough and uneven, and the electromagnetic shielding film can have better electrical conductivity and shielding effectiveness. Specifically, the conductive powder of the first conductive layer includes a dendritic conductive powder, and the dendritic conductive powder is excellent in mutual adhesion due to a dendritic shape, and can be electrically conductive in horizontal and vertical directions, and is dendritic conductive. The particle size of the conductive particles of the powder is 5-20 um. Since the particle size of the conductive particles of the first conductive layer is larger, the adhesion between the conductive particles is further increased, so that the first conductive layer has good electrical conductivity and Shield performance.

In order to prevent the particle size of the conductive particles of the first conductive layer from being excessively large, and the coating thickness is small, the conductive layer of the electromagnetic shielding film has a rough appearance and unevenness, and the second conductive layer is coated on one side of the first conductive layer due to The thickness of the conductive layer of the overall electromagnetic shielding film is not increased, so that the cost is not increased, and since the conductive particles of the first conductive layer have a large particle diameter, the conductive properties of the conductive layer of the electromagnetic shielding film are not lowered. Shield performance.

Specifically, the conductive powder of the second conductive layer comprises a sheet-like conductive powder or a spherical conductive powder, and the sheet-like conductive powder or the spherical conductive powder provides the second conductive layer with good electrical conductivity, thereby enabling the second conductive layer to be electrically conductive with the first conductive layer. The layer is turned on, and since the particle diameter of the conductive particles of the sheet-like conductive powder or the spherical conductive powder is the same as the thickness of the second conductive layer, the vertical conductivity between the second conductive layer and the first conductive layer is satisfied, so that the second The conductive layer mainly functions as a vertical conduction, and the first conductive layer serves as a main shielding function, so that the shielding effect of the conductive layer of the entire electromagnetic shielding film is more excellent, and the particle diameter of the conductive particles of the second conductive layer and the second conductive layer The thickness of the layer is the same, and the appearance of the second conductive layer can be made flat, thereby making up for the appearance of the conductive layer being rough and uneven due to the excessively large coating particle size of the conductive particles of the first conductive layer.

DRAWINGS

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the specific embodiments or the description of the prior art will be briefly described below, and obviously, the attached in the following description The drawings are some embodiments of the present invention, and other drawings may be obtained from those of ordinary skill in the art without departing from the scope of the invention.

1 is a schematic structural view of an electromagnetic shielding film in the prior art;

2 is a schematic structural view of a first embodiment of an electromagnetic shielding film according to an embodiment of the present invention;

3 is a schematic structural view of a second embodiment of an electromagnetic shielding film according to an embodiment of the present invention;

4 is a schematic structural view of a third embodiment of an electromagnetic shielding film according to an embodiment of the present invention.

Icons: 100 - first conductive layer; 200 - second conductive layer; 300 - carrier film; 400 - insulating layer; 500 - protective film; 600 - metal layer; 700 - graphene layer.

Detailed ways

The technical solutions of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is obvious that the described embodiments are a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" appear. The orientation or positional relationship indicated by the figures is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description of the present invention and a simplified description, and does not indicate or imply that the device or component referred to has a specific orientation. It is constructed and operated in a particular orientation and is therefore not to be construed as limiting the invention. Moreover, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The inventors have found that in the manufacturing process of the electromagnetic shielding film, in order to obtain an excellent electrical conductivity and shielding effectiveness of the electromagnetic shielding film, the conductive particles of the conductive layer select a dendritic, sheet-like or spherical conductive powder having a larger particle diameter. Usually, the conductive powder has a particle size of 5-20 um. Due to the larger particle size, the adhesion between the conductive particles is increased, so that the electrical conductivity and shielding effectiveness of the electromagnetic shielding film are good, but since the particle size of the conductive particles is large when the conductive layer is applied, when the conductive layer is coated 5-15 um At the thickness, the larger particle size makes the appearance of the conductive layer rougher and uneven.

In order to improve the roughness and unevenness of the appearance of the conductive layer, it is usually improved by increasing the thickness of the conductive layer, but the increase in the thickness of the conductive layer causes an increase in cost, and the appearance of the conductive layer is improved by reducing the particle diameter of the conductive particles. The roughness and unevenness of the conductive particles are reduced due to the decrease in the particle size of the conductive particles, which in turn affects the conductivity of the conductive layer and the shielding effectiveness.

Embodiment 1 and Embodiment 2 will be described in detail below with reference to the accompanying drawings:

1 is a schematic structural view of an electromagnetic shielding film in the prior art; FIG. 2 is a schematic structural view of a first embodiment of an electromagnetic shielding film according to an embodiment of the present invention; FIG. 3 is a schematic view of an electromagnetic shielding film according to an embodiment of the present invention. FIG. 4 is a schematic structural view of a third embodiment of an electromagnetic shielding film according to an embodiment of the present invention.

Referring to FIG. 1 to FIG. 1 , FIG. 1 is a schematic structural diagram of an electromagnetic shielding film in the prior art. In the prior art, the conductive layer of the electromagnetic shielding film uses only a single layer of the first conductive layer 100. The particle size of the conductive particles of the conductive layer 100 is too large, and when the coating thickness is small, the conductive layer of the electromagnetic shielding film is likely to be rough and uneven. In order to improve the roughness and unevenness of the appearance of the conductive layer, it is possible to improve the method of increasing the thickness of the first conductive layer 100. However, the increase in the thickness of the first conductive layer 100 requires more conductive material, which causes an increase in cost. If the roughness of the conductive layer is improved by reducing the particle size of the conductive particles, the unevenness of the conductive particles is reduced, and the mutual adhesion between the conductive particles is lowered, which in turn affects the conductivity of the conductive layer and the shielding effectiveness.

2-4 is a schematic structural diagram of an electromagnetic shielding film provided by the embodiment. The embodiment provides a conductive layer of an electromagnetic shielding film, and the conductive layer of the electromagnetic shielding film includes a first conductive layer 100 and is coated on the first The second conductive layer 200 on one side of the conductive layer 100, specifically:

The conductive powder of the first conductive layer 100 comprises a dendritic conductive powder, and the conductive particles of the dendritic conductive powder have a particle size of 5-20 um;

The conductive powder of the second conductive layer 200 includes a sheet-like conductive powder or a spherical conductive powder, and the particle diameter of the conductive particles of the sheet-like conductive powder or the spherical conductive powder is the same as the thickness of the second conductive layer 200. As shown in FIG. 2, the conductive layer of the electromagnetic shielding film includes a first conductive layer 100 and a second conductive layer 200. The second conductive layer 200 is coated on one side of the first conductive layer 100, and is improved by using two conductive layers. The conductive layer of the electromagnetic shielding film has a rough appearance and an unevenness, and at the same time, the electromagnetic shielding film can have better electrical conductivity and shielding effectiveness. Specifically, the conductive powder of the first conductive layer 100 includes a dendritic conductive powder, and the conductive particles in the dendritic conductive powder have a dendritic shape, and the conductive particles are excellent in adhesion to each other, so that the first conductive layer 100 can be Electrical conduction is achieved both in the horizontal direction of the plane in which the first conductive layer 100 is located and in the vertical direction perpendicular to the plane in which the first conductive layer 100 is located. Moreover, the conductive particles of the dendritic conductive powder may have a particle diameter of 5-20 um. Since the particle diameter of the conductive particles of the first conductive layer 100 is larger, the adhesion between the conductive particles is further increased, thereby making the first conductive Layer 100 has good electrical conductivity and shielding effectiveness.

In the embodiment of the present application, in the first conductive layer 100, in order to prevent the particle size of the conductive particles of the first conductive layer 100 from being excessively large, and the coating thickness is small, the surface of the first conductive layer 100 is rough and uneven. One side is also coated with a second conductive layer 200. The conductive layer of the electromagnetic shielding film in the embodiment of the present application is provided by two conductive layers, and the conductive powder used in the two conductive layers is different, the first conductive layer 100 includes a dendritic conductive powder, and the second conductive layer 200 includes a sheet-shaped conductive layer. Powder or spherical conductive powder. The first conductive layer 100 in the conductive layer in the embodiment of the present application includes a dendritic conductive powder, and the conductive particles of the dendritic conductive powder have better adhesion and can achieve a level compared to an electromagnetic shielding film that uses only one conductive layer. Conductive conduction in the direction and the vertical direction, while the second conductive layer 200 passes through the sheet-like conductive powder or the spherical conductive powder, and the particle diameter of the conductive particles of the sheet-like conductive powder or the spherical conductive powder is the same as or similar to the thickness of the second conductive layer. The sheet-like conductive powder or the spherical conductive powder can achieve electrical conduction in the vertical direction between the second conductive layer 200 and the first conductive layer 100. The conductive layer of the electromagnetic shielding film having the first conductive layer 100 and the second conductive layer 200 in the embodiment of the present application is not provided with the same electromagnetic shielding performance as compared with the electromagnetic shielding film provided with only one conductive layer. The thickness of the overall conductive layer is increased, since the thickness of the conductive layer of the overall electromagnetic shielding film is not increased, so that the cost is not increased, and since the particle size of the conductive particles of the first conductive layer 100 is large, it does not decrease. The conductive layer and the shielding effectiveness of the conductive layer of the electromagnetic shielding film make the conductive layer in the embodiment of the present application have good electromagnetic shielding property.

In addition, if the thickness of the conductive layer of the electromagnetic shielding film in the embodiment of the present application is the same as the thickness of the conductive layer in the electromagnetic shielding film provided with only one conductive layer, the conductive layer of the electromagnetic shielding film in the embodiment of the present application has the first a conductive layer 100 and a second conductive layer 200. The first conductive layer 100 includes a dendritic conductive powder, and the second conductive layer 200 includes at least one of a sheet-like conductive powder or a spherical conductive powder. The electromagnetic shielding in the embodiment of the present application. The conductive layer of the film has better electromagnetic shielding performance and better electrical conductivity than the single conductive layer.

Specifically, the conductive powder of the second conductive layer 200 includes a sheet-like conductive powder or a spherical conductive powder, and the sheet-like conductive powder or the spherical conductive powder provides the second conductive layer 200 with good electrical conductivity, thereby enabling the second conductive layer 200 to The first conductive layer 100 is turned on, and since the particle diameter of the conductive particles of the sheet-like conductive powder or the spherical conductive powder is the same as the thickness of the second conductive layer 200, the vertical between the second conductive layer 200 and the first conductive layer 100 is satisfied. The conductivity makes the second conductive layer 200 mainly perform vertical conduction, and the first conductive layer 100 plays a main shielding role, thereby making the shielding effect of the conductive layer of the entire electromagnetic shielding film more excellent, and the second conductive layer 200 The particle diameter of the conductive particles is the same as the thickness of the second conductive layer 200, and the appearance of the second conductive layer 200 can be made flat, thereby compensating for the coating thickness being low due to the excessive particle size of the conductive particles of the first conductive layer 100. The resulting conductive layer has a rough appearance and is uneven.

In a specific embodiment, the thickness of the first conductive layer 100 may be 5-10 um, and the thickness of the conductive layer of the electromagnetic shielding film is generally 5-15 um, and the thickness of the first conductive layer 100 is set to 5-10 um. The first conductive layer 100 can play a main shielding role, and at the same time, since the particle diameter of the conductive particles of the first conductive layer 100 is large, and the thickness of the first conductive layer 100 is low, the surface of the first conductive layer 100 is relatively Rough, uneven, the particle size of the conductive particles of the sheet-like conductive powder or the spherical conductive powder of the second conductive layer 200 is set to 1-3 um, and the thickness of the second conductive layer 200 is 1-3 um, so that the second conductive layer The thickness of 200 is the same as or similar to the particle diameter of the conductive particles of the second conductive layer 200, satisfying the vertical conductivity between the second conductive layer 200 and the first conductive layer 100, thereby making the conductive layer of the entire electromagnetic shielding film The shielding effect is more excellent, and at the same time, the surface of the second conductive layer 200 can be flattened, and the appearance of the conductive layer due to the excessively large coating thickness of the conductive particles of the first conductive layer 100 and the unevenness of the coating layer are rough and uneven. Since the thickness of the first conductive layer 100 is 5-10 um and the thickness of the second conductive layer 200 is 1-3 um, the thickness of the conductive layer of the overall electromagnetic shielding film is not increased, so that no increase in cost is caused.

In an alternative embodiment of the present invention, the powder content of the dendritic conductive powder in the first conductive layer 100 may be 30-40%, so that the powder content of the dendritic conductive powder in the first conductive layer 100 is small. Therefore, the processing cost can be reduced, and at the same time, since the conductive particles in the dendritic conductive powder have a dendritic shape, the conductive density of the conductive particles in the dendritic conductive powder is also large in the case where the content of the conductive layer powder is lowered. The cost of the electromagnetic shielding film is lowered and the shielding effectiveness is not affected. Through experimental research, the first conductive layer 100 of the electromagnetic shielding film on the soft board and the hard board is connected with the soft board and the hard board. The experimental results show that the shielding performance of the conductive layer of the electromagnetic shielding film provided by the embodiment reaches 50 dB. As described above, the shielding effect is excellent, and the cost of the conductive layer of the electromagnetic shielding film is lowered due to the small powder content of the dendritic conductive powder in the first conductive layer 100.

Specifically, the conductive particles of the dendritic conductive powder in the first conductive layer 100 may include one or more of silver, copper, iron, nickel, zinc, a silver alloy, a copper alloy, an iron alloy, a nickel alloy, and a zinc alloy. The conductive particles in the sheet-like conductive powder or the spherical conductive powder in the second conductive layer 200 may include one or more of silver, copper, iron, nickel, zinc, a silver alloy, a copper alloy, an iron alloy, a nickel alloy, and a zinc alloy. . The conductive particles are made of easily conductive silver, copper, iron, nickel, zinc, silver alloy, copper alloy, iron alloy, nickel alloy and zinc alloy, which can ensure the electromagnetic shielding film has excellent electrical conductivity and shielding effectiveness.

The material of the first conductive layer 100 may include at least one of a thermosetting epoxy resin, an acrylic resin, or a polyurethane. The material of the second conductive layer 200 may include at least one of a thermosetting epoxy resin, an acrylic resin, or a polyurethane. Kind. Thermosetting epoxy resin, acrylic resin or polyurethane has good physical and chemical properties. It has excellent bonding strength to metal and non-metal materials, good dielectric properties, small deformation shrinkage, and good dimensional stability of products. The hardness is high and the flexibility is good, so that the functions of the first conductive layer 100 and the second conductive layer 200 can be ensured.

This embodiment provides an electromagnetic shielding film including the conductive layer of the electromagnetic shielding film in Embodiment 1. Since the conductive layer uses two conductive layers, in order to prevent the particle size of the conductive particles of the first conductive layer 100 from being too large, and the coating thickness is small, the conductive layer of the electromagnetic shielding film has a rough appearance and is uneven, and the first conductive layer 100 is in the first conductive layer 100. Coating the second conductive layer 200 on one side does not increase the thickness of the conductive layer of the overall electromagnetic shielding film, and thus does not cause an increase in cost, and at the same time, since the particle diameter of the conductive particles of the first conductive layer 100 is large, It does not reduce the electrical conductivity and shielding effectiveness of the conductive layer of the electromagnetic shielding film.

In a specific embodiment, as shown in FIG. 2, the electromagnetic shielding film may further include a carrier film 300, an insulating layer 400, and a protective film 500. Specifically, the insulating layer 400 is coated on one side of the carrier film 300, the first conductive layer 100 is coated on the side of the insulating layer 400 facing away from the carrier film 300, and the protective film 500 is attached to the second conductive layer 200 away from the first conductive layer. One side of the 100 is set, so that a complete electromagnetic shielding film can be obtained, and the safety and service life of the electromagnetic shielding film can be improved.

Specifically, the material of the insulating layer 400 includes a thermosetting epoxy resin, an acrylic resin or a urethane glue. Thermosetting epoxy resin, acrylic resin or polyurethane glue has good physical and chemical properties. It has excellent bonding strength to metal and non-metal materials, good dielectric properties, small deformation shrinkage, and dimensional stability of products. Good, high hardness, and good flexibility, so that the function of the insulating layer 400 can be ensured.

The material of the protective film 500 includes a release film or a release paper. Usually, in order to increase the release force of the plastic film, the plastic film is plasma-treated, so that it can exhibit extremely light and stable release force for various organic pressure-sensitive adhesives. The use of the release film or the release paper of the protective film 500 enables the protective film 500 to achieve an extremely light and stable release force upon peeling.

In an alternative embodiment of this embodiment, as shown in FIG. 3, a metal layer 600 is further disposed between the insulating layer 400 and the conductive layer of the electromagnetic shielding film. The metal layer 600 can be selectively disposed according to actual needs, and the metal layer 600 can be disposed to enable the electromagnetic shielding film to obtain better electrical conductivity and shielding performance. The metal layer may be disposed between the insulating layer 400 and the first conductive layer 100 as a third conductive layer.

In another alternative of this embodiment, as shown in FIG. 4, a graphene layer 700 is further disposed between the insulating layer 400 and the conductive layer of the electromagnetic shielding film. The graphene layer 700 can be selected according to actual needs. Graphene is a new type of nano material which is the thinnest, strongest, and most conductive and thermally conductive. The setting of the graphene layer 700 can make the electromagnetic shielding film better. Conductivity and shielding properties. The graphene layer 700 may be disposed between the insulating layer 400 and the first conductive layer 100 as a third conductive layer.

The embodiment of the present application further provides a method for preparing an electromagnetic shielding film, which comprises the following steps.

In step S101, a carrier film 300 is provided.

The thickness and size of the carrier film 300 can be determined according to actual needs. The material of the carrier film 300 can also be selected according to actual conditions. The specific material of the carrier film 300 is not limited in the embodiment of the present application.

Step S102, forming a first conductive layer 100 on the side of the carrier film, and the conductive powder of the first conductive layer 100 comprises a dendritic conductive powder.

When the electromagnetic shielding film is formed, a conductive material may be coated on the side of the carrier film 300, and the branched conductive powder is included to form the first conductive layer 100. The conductive particles of the dendritic conductive powder may have a particle diameter of 5-20 um.

Before the first conductive layer 100 is formed, the insulating layer 400 may be formed on the side of the carrier film 300, and the insulating layer 400 may be formed by coating an insulating material. After the insulating layer 400 is completed, the first conductive layer 100 is formed on the side of the insulating layer 400 away from the carrier film 300.

In step S103, a second conductive layer 200 is formed on a side of the first conductive layer 100 away from the insulating layer 400. The conductive powder of the second conductive layer 200 includes a sheet-shaped conductive powder or a spherical conductive powder.

After the first conductive layer 100 is completed, the second conductive layer 200 can be formed on the side of the first conductive layer 100 away from the carrier film 300. The second conductive layer 200 can be formed by coating a conductive material to form a second conductive layer. The conductive powder of 200 includes at least one of a sheet-like conductive powder and a spherical conductive powder. The particle diameter of the conductive particles of the sheet-like conductive powder or the spherical conductive powder is the same as or similar to the thickness of the second conductive layer 200. The conductive particles of the sheet-like conductive powder or the spherical conductive powder may have a particle diameter of 1-3 um, and the second conductive layer 200 may have a thickness of 1-3 um.

In a specific embodiment, after the step of forming the insulating layer 400, the method may further include the following steps.

Step S104, at least one of the metal layer 600 or the graphene layer 700 is formed on a side of the insulating layer 400 away from the carrier film 300 to form a third conductive layer.

By forming the third conductive layer, the overall shielding performance of the electromagnetic shielding film and the electrical conductivity of the conductive layer can also be improved. The thickness of the third conductive layer and the materials selected may be determined according to actual conditions.

In another specific embodiment, after the step of forming the second conductive layer, the method may further include the following steps.

In step S105, the protective film 500 is attached to the side of the second conductive layer 200 away from the first conductive layer 100.

After the second conductive layer 200 is completed, the release film or the release paper may be attached to the side of the second conductive layer 200 away from the first conductive layer 100 to form a protective film 500 to achieve electrical conduction in the electromagnetic shielding film. The protection of the layer prevents other objects from damaging the conductive layer when it comes into contact with other objects.

In the embodiment of the present application, a conductive layer having two conductive powders is formed by forming the first conductive layer 100 and the second conductive layer 200 on the carrier film 300, and the conductive powder used in the first conductive layer 100 includes a dendritic shape. The conductive powder, the conductive powder used in the second conductive layer 200 includes at least one of a sheet-like conductive powder or a spherical conductive powder. The conductive particles of the dendritic conductive powder have better adhesion, and electrical conduction in the horizontal direction and the vertical direction can be achieved, while the second conductive layer 200 passes through the sheet-shaped conductive powder or the spherical conductive powder, and the sheet-like conductive powder or the spherical conductive powder The particle diameter of the conductive particles is the same as or similar to the thickness of the second conductive layer, so that the sheet-like conductive powder or the spherical conductive powder can achieve electrical conduction in the vertical direction between the second conductive layer 200 and the first conductive layer 100. The conductive layer of the electromagnetic shielding film having the first conductive layer 100 and the second conductive layer 200 in the embodiment of the present application is provided with the same electromagnetic shielding performance as compared with the electromagnetic shielding film provided with only one conductive layer. The thickness of the overall conductive layer is not increased, and since the thickness of the conductive layer of the overall electromagnetic shielding film is not increased, the cost is not increased, and since the particle diameter of the conductive particles of the first conductive layer 100 is large, The conductive performance and shielding effectiveness of the conductive layer in the electromagnetic shielding film are reduced, so that the electromagnetic shielding film in the embodiment of the present application has good electromagnetic shielding property.

Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Industrial applicability

The embodiment of the invention provides a conductive layer of an electromagnetic shielding film, an electromagnetic shielding film and a preparation method thereof, and the electromagnetic shielding film is improved by providing a conductive layer including a first conductive layer and a second conductive layer in the electromagnetic shielding film. The single-layer conductive layer indicates a rough and uneven phenomenon, and at the same time, the electromagnetic shielding film can have better electrical conductivity and shielding effectiveness.

Claims

A conductive layer of an electromagnetic shielding film, comprising: a first conductive layer (100) and a second conductive layer (200) coated on one side of the first conductive layer (100);

The conductive powder of the first conductive layer (100) comprises a dendritic conductive powder, and the conductive particles of the dendritic conductive powder have a particle diameter of 5-20 um;

The conductive powder of the second conductive layer (200) includes a sheet-like conductive powder or a spherical conductive powder, and the particle diameter of the conductive powder of the sheet-like conductive powder or the spherical conductive powder and the second conductive layer (200) The thickness is the same.
The conductive layer of the electromagnetic shielding film according to claim 1, wherein the first conductive layer (100) has a thickness of 5 to 10 um.
The conductive layer of the electromagnetic shielding film according to any one of claims 1 to 2, wherein the sheet-like conductive powder or the conductive particles of the spherical conductive powder have a particle diameter of 1-3 um, the second The conductive layer (200) has a thickness of 1-3 um.
The conductive layer of the electromagnetic shielding film according to claim 1 or 2, wherein the dendritic conductive powder has a powder content of 30-40% in the first conductive layer (100).
The conductive layer of the electromagnetic shielding film according to any one of claims 1 to 4, wherein the conductive particles of the first conductive layer (100) and the second conductive layer (200) comprise silver, copper, One or more of iron, nickel, zinc, silver alloy, copper alloy, iron alloy, nickel alloy, and zinc alloy.
The conductive layer of the electromagnetic shielding film according to any one of claims 1 to 5, wherein the material of the first conductive layer (100) comprises at least one of a thermosetting epoxy resin, an acrylic resin or a polyurethane. Kind.
The conductive layer of the electromagnetic shielding film according to any one of claims 1 to 5, wherein the material of the second conductive layer (200) comprises at least one of a thermosetting epoxy resin, an acrylic resin or a polyurethane. Kind.
The conductive layer of the electromagnetic shielding film according to any one of claims 1 to 7, characterized in that the side of the first conductive layer (100) away from the second conductive layer (200) is further coated with A third conductive layer comprising a metal layer and/or a graphene layer.
The conductive layer of the electromagnetic shielding film according to any one of claims 1 to 8, wherein the conductive powder of the second conductive layer (200) comprises at least one of a sheet-like conductive powder and a spherical conductive powder.
An electromagnetic shielding film comprising the conductive layer of the electromagnetic shielding film according to any one of claims 1-9.
The electromagnetic shielding film according to claim 10, further comprising a carrier film (300), an insulating layer (400), and a protective film (500);

The insulating layer (400) is coated on one side of the carrier film (300), and the first conductive layer (100) is coated on the insulating layer (400) away from the carrier film (300) On the side, the protective film (500) is disposed on a side of the second conductive layer (200) facing away from the first conductive layer (100).
The electromagnetic shielding film according to any one of claims 10 or 11, wherein the material of the insulating layer (400) comprises a thermosetting epoxy resin, an acrylic resin or a urethane glue.
The electromagnetic shielding film according to any one of claims 10 or 11, wherein the material of the protective film (500) comprises a release film or a release paper.
The electromagnetic shielding film according to any one of claims 10 to 14, wherein a metal layer (600) or graphene is further disposed between the insulating layer (400) and the conductive layer of the electromagnetic shielding film. Layer (700).
A method for preparing an electromagnetic shielding film, comprising:

Providing a carrier film;

Forming a first conductive layer on one side of the carrier film, and the conductive powder of the first conductive layer comprises a dendritic conductive powder;

A second conductive layer is formed on a side of the first conductive layer away from the insulating layer, and the conductive powder of the second conductive layer (200) comprises a sheet-like conductive powder or a spherical conductive powder.
The method of preparing an electromagnetic shielding film according to claim 15, wherein before the step of forming the first conductive layer, the method further comprises:

An insulating material is coated on one side of the carrier film to form an insulating layer, and the first conductive layer is disposed on a side of the insulating layer away from the carrier film.
The method of manufacturing an electromagnetic shielding film according to claim 15, wherein after the step of forming an insulating layer, the method further comprises:

A metal layer or a graphene layer is formed on a side of the insulating layer away from the carrier film to form a third conductive layer.
The method of preparing an electromagnetic shielding film according to claim 15, wherein after the step of forming the second conductive layer, the method further comprises:

A protective film is attached to a side of the second conductive layer away from the first conductive layer.