CN207885103U - An electromagnetic wave shielding film - Google Patents

Abstract

The utility model provides an electromagnetic wave shielding film, at least, including one deck electromagnetic shield layer, one side of electromagnetic shield layer is the adhesive linkage, the opposite side is the insulating layer, at least one side of insulating layer is coarse, the roughness is 2 ~ 10 mu m, the electromagnetic shield layer is copper plate or silvered film, the adhesive linkage is modified epoxy layer, modified polyurethane layer or modified acrylate gluing agent layer, there is the inorganic particle adhesive layer in addition between insulating layer and the electromagnetic shield layer, the thickness of insulating layer is 1 ~ 10 mu m, the thickness of electromagnetic shield layer is 10 ~ 5000nm, the surface of tie coat has still pasted the protection film, electromagnetic wave shielding film still includes from type carrier film layer. The utility model discloses a to insulating layer surface coating contain inorganic particle's resin or adhesive, perhaps directly add inorganic particle in the insulating layer material, form the insulating layer of surface roughness, reach the purpose that carries out the alligatoring to insulating layer and electromagnetic shield faying face, ground resistance when showing and having reduced the electromagnetic shielding membrane and using.

Description

An electromagnetic wave shielding film

technical field

The utility model belongs to the field of insulation technology, in particular to an electromagnetic wave shielding film.

Background technique

In recent years, with the large increase in the demand for electromagnetic wave applications, people's research on electromagnetic waves has gradually deepened, and more and more application bands have been developed. In order to meet the needs of long-distance transmission and detection, the electromagnetic wave transmission power of radar, satellite communication and other equipment is also gradually increasing, and the intensity of electromagnetic waves has increased significantly, especially in the wide band from radio waves to microwaves. At present, electromagnetic waves are widely used in various fields such as medical care, television broadcasting, mobile communication, and optics, which provide many conveniences for life, but too much application of electromagnetic waves has caused a certain degree of electromagnetic wave pollution, making the electromagnetic environment of the space background increasingly complicated. , Various fields have begun to put forward requirements for anti-electromagnetic interference. In recent years, the research on optical technology has continued to deepen, and the diversity of applications of optical systems requires that they must effectively shield electromagnetic waves that interfere with the system under the premise of meeting normal use, especially in military and aerospace fields. The optical observation and detection equipment on various weapons and aircraft must meet two requirements at the same time: on the one hand, it can effectively shield the electromagnetic waves that affect the normal operation of the electronic devices in the system and interfere with the signal receiving equipment; It has excellent light transmission characteristics, so that it does not affect the imaging quality of the optical system, so as to meet the requirements of equipment detection and observation. In order to solve the problem of electromagnetic shielding, we began to continuously research and develop electromagnetic product shielding technology.

The core of the shielding film for circuit boards is the electromagnetic shielding layer. Around the electromagnetic shielding layer, there are many electromagnetic shielding films in various hierarchical forms. CN103763893A discloses an electromagnetic wave shielding film and a printed circuit board containing the shielding film. The manufacturing method includes hot pressing and curing the electromagnetic shielding film and the circuit board in the thickness direction, and using the rough surface of the electromagnetic shielding layer to pierce the adhesive layer to achieve grounding. Either the electromagnetic shielding film and the circuit board are heat-pressed and cured in the thickness direction, and the conductive material is used to pierce the shielding film to achieve grounding, or the electromagnetic shielding film and the circuit board are heat-pressed and cured in the thickness direction to form through holes or blind holes on the circuit board , the hole is metallized to achieve grounding. The shielding film adhesive layer of the invention does not contain conductive particles, which reduces the cost and insertion loss, and can meet the development needs of high-speed and high-frequency electronic products. The surface roughening method is the copper foil roughening method of the circuit board, which needs to be roughened first, then cured, and then passivated, or the method of micro-etching of the circuit board is used, which is roughened first and then passivated. These roughening methods The reagents used may pollute the environment, and some actually even contain toxic substances. CN106061107A discloses a rigid-flex circuit board with an electromagnetic shielding film and a preparation method thereof. The rigid-flex circuit board with an electromagnetic shielding film includes a rigid region and a flexible region, and the rigid region includes sequentially stacked first rigid substrates board, bonding sheet, flexible sub-board, bonding sheet and a second rigid sub-board, the flexible area includes an electromagnetic shielding film, a cover film, a flexible sub-board, a cover film and an electromagnetic shielding film stacked in sequence, and the electromagnetic shielding film includes sequentially stacked The first release film, insulating layer, and conductive adhesive layer are stacked. The rigid-flexible circuit board with electromagnetic shielding film of the invention is used after the rigid-flexible circuit board is uncovered to expose the flexible area during the manufacturing process of the rigid-flexible board. The specially designed auxiliary gasket enables the electromagnetic shielding film to be well subjected to pressure and heat during the lamination process and to be reliably attached to the surface of the flexible zone. However, the material of the conductive adhesive layer in this invention is copper paste or silver paste, and the cost higher. CN104883866A discloses an electromagnetic shielding film with good thermal conductivity and its manufacturing process. The electromagnetic shielding film includes: a carrier film layer, a flexible ink layer, a thermally conductive ink layer, and a conductive adhesive layer coated on the thermally conductive ink layer. The thermally conductive ink layer endows the electromagnetic shielding film with good thermal conductivity, and the thermal conductivity can reach more than 2.0W/m*k. The flexible ink layer makes the electromagnetic shielding film have good flexibility, which meets the needs of flexible circuit boards. The invention The manufacturing process is easy to implement in existing industrial production, and is convenient for industrial popularization and application. However, the shielding film of the invention has many layers, which increases the manufacturing cost.

At present, the basic structure of the shielding film contains a conductive adhesive layer, which will increase the insertion loss of the circuit board, and the metal particles contained in the conductive adhesive layer will reduce the bendability of the circuit board. Therefore, in order to meet the requirements, it is hoped that the electromagnetic shielding film without conductive adhesive layer can be obtained by changing the formation method, material type and hierarchical structure of the electromagnetic shielding layer and insulating layer, so as to avoid the reduction of insertion loss and bending performance .

Utility model content

In order to solve the deficiencies of the prior art, the purpose of the utility model is to provide an electromagnetic wave shielding film.

In order to achieve the above goals, the utility model adopts the following technical solutions:

An electromagnetic wave shielding film, comprising at least one electromagnetic shielding layer, one side of the electromagnetic shielding layer is an adhesive layer, the other side is an insulating layer, at least one side of the insulating layer is rough, with a roughness of 2 to 10 μm, preferably 1-8 μm.

Preferably, the electromagnetic shielding layer is a copper-plated layer or a silver-plated layer.

Preferably, the electromagnetic shielding layer is a copper-plated layer of metal material or a silver-plated layer of metal material.

Further preferably, the metal material is one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt or copper.

Further preferably, the metal material is an alloy formed of at least two of aluminum, titanium, zinc, iron, nickel, chromium, cobalt or copper.

Preferably, the adhesive layer is a modified epoxy resin layer, a modified polyurethane layer or a modified acrylate adhesive layer.

Preferably, the insulating layer is a modified polyurethane layer containing inorganic particles, a modified acrylate layer or a modified epoxy insulating ink layer.

Preferably, there is an adhesive layer of inorganic particles between the insulating layer and the electromagnetic shielding layer.

Preferably, the particle size of the inorganic particles is 2-15 μm.

Preferably, the adhesive layer has a thickness of 1-15 μm.

Preferably, the insulating layer has a thickness of 1-10 μm.

Preferably, the thickness of the electromagnetic shielding layer is 10-5000 nm, and the electromagnetic shielding layer is a copper-plated layer or a silver-plated layer.

Preferably, a protective film is attached to the outer surface of the bonding layer.

Preferably, the electromagnetic wave shielding film further includes a base film and/or a protective film.

Beneficial effects of the utility model

1. On the basis of the prior art, the utility model forms an insulating layer with a rough outer surface by coating the outer surface of the insulating layer with resin or adhesive containing inorganic particles, or directly adding inorganic particles to the insulating layer material, so as to achieve The purpose of roughening the joint surface of the insulating layer and the electromagnetic shielding layer is to significantly reduce the grounding resistance when the electromagnetic shielding film is applied;

2. The utility model uses an insulating adhesive layer to achieve the same conductive effect as the conductive tape, and the grounding resistance is significantly reduced, which is conducive to reducing the electromagnetic interference of the circuit board and improving the transmission performance of the signal. At the same time, the heat resistance of the shielding film and peeling off The strength is not adversely affected, the bending resistance is significantly improved, and the service life of the product is increased.

Description of drawings

Fig. 1 is a structural schematic diagram of an electromagnetic shielding film containing an inorganic particle adhesive layer between an insulating layer and an electromagnetic shielding layer.

Fig. 2 is a schematic structural view of an electromagnetic shielding film in which an insulating layer contains inorganic particles.

Detailed ways

The following examples are intended to further illustrate the content of the utility model, rather than limit the protection scope of the utility model claims.

Example 1

As shown in Figure 1, a kind of electromagnetic wave shielding film, carrier film 4 is provided with insulating layer 2, is provided with electromagnetic shielding layer 1 on insulating layer 2, is provided with adhesive layer 3 on electromagnetic shielding layer 1, and adhesive layer 3 surface A protective film 6 is attached, wherein the carrier film 4 is a PET film containing a non-silicon release material. There is an inorganic particle adhesive layer 5 between the electromagnetic shielding layer 1 and the insulating layer 2 .

Example 2

As shown in Figure 2, a kind of electromagnetic wave shielding film, carrier film 4 is provided with insulating layer 2, is provided with electromagnetic shielding layer 1 on insulating layer 2, is provided with adhesive layer 3 on electromagnetic shielding layer 1, and the outside of adhesive layer 3 The surface is covered with a protective film 6, and the insulating layer 2 contains inorganic particles with a particle size of 2-15 μm. Wherein, the contact surface 7 between the insulating layer 2 and the carrier film 4 is not completely smooth, and the roughness of the contact surface 5 between the insulating layer 2 and the electromagnetic shielding layer 1 is 2-10 μm. The carrier film 4 is a PET heavy-release film.

The preparation method of electromagnetic shielding film in embodiment 1 and embodiment 2, comprises the following steps:

(1) Coating the insulating layer 2 on one side of the carrier film 4, roughening the insulating layer 2, or adding inorganic particles to the material of the insulating layer 2, forming an insulating layer 2 with a roughened surface;

(2) The roughened surface treated in step (1) forms an electromagnetic shielding layer 1 by vacuum evaporation or sputtering;

(3) the surface coating of the electromagnetic shielding layer 1 formed in step (2) forms an adhesive layer 3;

(4) Cover the surface of the adhesive layer 3 formed in step (3) with a protective film 6 .

In step (1), the roughening treatment is to coat modified epoxy resin, modified polyurethane or modified acrylate adhesive containing inorganic particles on the outer surface of the insulating layer 2, such as the inorganic particle adhesive in Example 1. Floor.

In this embodiment, inorganic particles are added to the material of the insulating layer to form an insulating layer with a roughened surface.

Comparative example 1

An electromagnetic wave shielding film, the carrier film is provided with an insulating layer, the insulating layer is provided with an electromagnetic shielding layer, and the electromagnetic shielding layer is provided with an adhesive layer, wherein the carrier film is a PET heavy-release film.

The preparation method of the electromagnetic wave shielding film comprises the following steps:

(1) Select a PET heavy release film with a thickness of 50 μm and a width of 250 to 1500 mm, and coat the insulating layer material on one side of the release surface, and form an insulating layer with a thickness of 2 μm after complete curing;

(2) on the surface of the insulating layer after step (1) is cured, the electromagnetic shielding layer material is directly deposited on the roughened surface by vacuum evaporation, and the deposition forms an electromagnetic shielding layer with a thickness of 100 nm;

(3) directly coating the bonding layer material on the surface of the electromagnetic shielding layer formed in step (2) to form a bonding layer with a thickness of 2 μm;

(4) Covering the surface of the adhesive layer formed in step (3) with a protective film.

Comparative example 2

An electromagnetic wave shielding film, the carrier film is provided with an insulating layer, the insulating layer is provided with an electromagnetic shielding layer, and the electromagnetic shielding layer is provided with an adhesive layer, wherein the carrier film is a PET heavy-release film.

The preparation method of the electromagnetic wave shielding film comprises the following steps:

(1) Select a PET heavy release film with a thickness of 40 μm and a width of 250 to 1500 mm, and coat the insulating layer material on one side of the release surface, and form an insulating layer with a thickness of 10 μm after complete curing;

(2) Deposit the electromagnetic shielding layer material on the roughened surface directly by sputtering on the surface of the insulating layer after step (1), and deposit and form an electromagnetic shielding layer with a thickness of 500nm;

(3) directly coating the bonding layer material on the surface of the electromagnetic shielding layer formed in step (2) to form a bonding layer with a thickness of 8 μm;

(4) Covering the surface of the adhesive layer formed in step (3) with a protective film.

The electromagnetic wave shielding films of Example 1 and Example 2 were compared with the electromagnetic wave shielding films of Comparative Example 1 and Comparative Example 2, and the results are shown in Table 1.

Table 1 Performance of electromagnetic wave shielding film

Performance Testing Example 1 Example 2 Comparative example 1 Comparative example 2 Ground resistance (ohm) 0.4 0.2 1.2 0.8 Peel strength (Kgf/cm) 1.1 1.3 1.4 1.0 Heat resistance (300℃, immersion tin) OK OK OK OK Bending resistance (times) 15600 10800 8320 9350

The roughness of the interface between layers has a significant impact on the grounding performance of the electromagnetic shielding film. Comparing Examples 1-2 and Comparative Examples 1-2 in Table 1, the grounding resistance of the interlayer bonding surface decreases significantly after the roughening treatment. The surface becomes soft and flows so that the electromagnetic shielding layer contacts the ground pad of the circuit board, which significantly reduces the ground resistance. The optimal roughness of the surface roughening treatment of the insulating layer is 1-8 μm. If the roughness is too small, the requirements for the pressing step difference are relatively high, and it is easy to have poor contact, resulting in increased grounding resistance. Excessive roughness will cause the adhesive layer to be coated. Uneven cloth.

The utility model adopts the insulating adhesive layer and can still achieve the conductive effect brought by the conductive adhesive tape, and the reduction of the grounding resistance is beneficial to reduce the electromagnetic interference of the circuit board and improve the signal transmission performance. There is no significant change in other properties, indicating that the electromagnetic wave shielding film is not adversely affected on the premise of ensuring electromagnetic shielding and good electrical conductivity (low grounding resistance). The bending resistance is significantly improved, which is beneficial to prolonging the service life of the product.

The above-mentioned embodiment is a preferred implementation of the utility model. In addition, the utility model can also be realized in other ways. Any obvious replacement is within the scope of protection of the utility model without departing from the concept of the utility model. Inside.

Claims (10)

1. An electromagnetic shielding film, characterized in that it comprises at least one layer of electromagnetic shielding layer, one side of the electromagnetic shielding layer is an adhesive layer, and the other side is an insulating layer, and at least one side of the insulating layer is rough , the roughness is 2-10μm. 2. The electromagnetic wave shielding film according to claim 1, wherein the electromagnetic shielding layer is a copper-plated layer or a silver-plated layer. 3. The electromagnetic wave shielding film according to claim 1, wherein the adhesive layer is a modified epoxy resin layer, a modified polyurethane layer or a modified acrylate adhesive layer. 4. The electromagnetic wave shielding film according to claim 1, wherein the insulating layer is a modified polyurethane layer containing inorganic particles, a modified acrylate layer or a modified epoxy insulating ink layer. 5. The electromagnetic wave shielding film according to claim 1, characterized in that there is an adhesive layer of inorganic particles between the insulating layer and the electromagnetic shielding layer. 6 . The electromagnetic wave shielding film according to claim 1 , wherein the adhesive layer has a thickness of 1-15 μm. 7 . The electromagnetic wave shielding film according to claim 1 , wherein the insulating layer has a thickness of 1-10 μm. 8. The electromagnetic wave shielding film according to claim 1, wherein the thickness of the electromagnetic shielding layer is 10-5000 nm. 9. The electromagnetic wave shielding film according to claim 1, characterized in that, a protective film is attached to the outer surface of the adhesive layer. 10. The electromagnetic wave shielding film according to claim 1, characterized in that, the electromagnetic wave shielding film further comprises a base film and/or a protective film.