KR102459013B1 - Electromagnetic wave absorber and preparing method thereof - Google Patents

Abstract

The present invention provides an electromagnetic wave absorber and a preparing method thereof, wherein the electromagnetic wave absorber includes a protective layer for protecting a metal magnetic powder (MMP) layer included in the electromagnetic wave absorber so as to improve resistance to physical and chemical impact applied to an exposed surface of the MMP layer.

Description

Electromagnetic wave absorber and manufacturing method thereof

The present invention relates to an electromagnetic wave absorber having a cover-lay-integrated structure used in a flexible printed circuit board (FPCB) process, and more specifically, a protective layer for protecting the electromagnetic wave absorption layer included in the electromagnetic wave absorber. By laminating, it relates to an electromagnetic wave absorber having a coverlay-integrated structure having improved resistance to physical and chemical shocks, and a method for manufacturing the same.

Recently, as electronic components developed as electronic products become smaller and lighter, flexible circuit boards (FPCBs) that have excellent workability, have strong heat resistance, bending resistance, and chemical resistance, and are resistant to heat are widely used in various electronic components.

On the other hand, with the development of electronic and communication technologies, electromagnetic interference (EMI) problems such as causing malfunctions of devices due to mutual interference of electromagnetic waves are becoming more serious. In addition, as it is continuously reported that electromagnetic waves generated from electronic devices adversely affect the human body, in order to prevent the effects of electromagnetic waves, electromagnetic wave absorbers are applied to electronic components.

The electromagnetic wave absorber is formed by coating a liquid containing metal magnetic powder (MMP) used as a material for absorbing electromagnetic waves on a coverlay film (insulation film for circuit protection) to form a metal magnetic powder layer (MMP). It is known to manufacture an electromagnetic wave absorber of a coverlay-integrated structure by forming a layer).

During the FPCB process, the MMP layer is exposed in the hot press lamination process and surface treatment process (solder plating or gold plating, etc.) There is a problem that Accordingly, there is a need for technology development for improving resistance to physical and chemical shocks applied to the exposed surface of the MMP layer of the electromagnetic wave absorber.

An object of the present invention is to provide an electromagnetic wave absorber capable of improving resistance to physical and chemical shocks applied to an exposed surface of an MMP layer (Metal Magnetic Powder layer), and a method for manufacturing the same, compared to a conventional electromagnetic wave absorber.

The object of the present invention is not limited to the above-mentioned object, and other objects and advantages of the present invention not mentioned may be understood by the following description, and will be more clearly understood by the examples of the present invention. Moreover, it will be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

In order to solve the above technical problem, according to an aspect of the present invention, a first to-be-coated member layer; a metal foil layer formed under the first to-be-coated member layer; a first adhesive layer formed by coating a first liquid crude liquid containing a heat-resistant resin on a lower portion of the metal foil layer; an MMP layer (Magnetic Metal Powder Layer) formed of a composition including magnetic metal particles and a binder resin under the first adhesive layer; a second to-be-coated member layer formed under the MMP layer; and a second adhesive layer formed by coating a second liquid crude liquid containing a heat-resistant and insulating resin under the second to-be-coated member layer, wherein the MMP layer is disposed between the MMP layer and the first adhesive layer. It is possible to provide an electromagnetic wave absorber of a coverlay-integrated structure, characterized in that a protective layer for protection is additionally disposed.

In this case, the protective layer for protecting the MMP layer may be formed of one selected from the group consisting of a polyimide (PI) film, a polyethylene terephthalate (PET) film, and a polyethylene naphthalate (PEN) film.

According to another aspect of the present invention, (a) applying a pressure-sensitive adhesive to the lower portion of the first to-be-coated member layer, and then disposing a metal foil layer, and then lamination (lamination) to prepare a first coating product; (b) a second liquid crude liquid containing heat-resistant and insulating resin is applied on the second to-be-coated member layer, coated to form a second adhesive layer with a thickness of 10 to 30 μm, and then laminated with a release base layer to obtain a second preparing a coated product; (c) forming an MMP layer (Magnetic Metal Powder Layer) by coating a composition containing magnetic metal particles and a binder resin on one surface of the protective layer having a thickness of 2 to 7 μm; (d) preparing a third coated product by arranging the second coated member layer of the second coated product in contact with the lower MMP layer formed on one surface of the protective layer in step (c), and then laminating; and (e) coating a first liquid crude liquid containing a heat-resistant resin on the lower portion of the metal foil layer of the first coating product of step (a) to form a first adhesive layer having a thickness of 3 to 10 μm, and then After arranging the protective layer of the third coating product prepared in step (d) in contact with the lower portion of the first adhesive layer, lamination to prepare a fourth coating product; Manufacturing of an electromagnetic wave absorber comprising a method can be provided.

The electromagnetic wave absorber according to the present invention has an effect of improving resistance to physical and chemical shocks applied to the exposed surface of the MMP layer while having an MMP layer (Metal Magnetic Powder layer) having excellent electromagnetic wave absorption effect.

In addition, the method for manufacturing an electromagnetic wave absorber according to the present invention can manufacture an electromagnetic wave absorber having an integrated coverlay structure, and has the effect of achieving a thin film of the electromagnetic wave absorber and increased production efficiency.

The effect of the present specification is not limited to the above-mentioned effects, and another effect not mentioned will be clearly understood by those skilled in the art from the following description. In addition to the above-described effects, the specific effects of the present invention will be described together while describing specific details for carrying out the invention below.

1 and 2 are cross-sectional views of an electromagnetic wave absorber having a coverlay-integrated structure according to an embodiment of the present invention.
3 and 4 show the gold plating evaluation results performed according to Experimental Example 2 for Comparative Examples 1 and 1, respectively, of the present invention.

The above-described objects, features and advantages will be described below in detail with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention pertains will be able to easily implement the technical idea of the present invention. In describing the present invention, if it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

Among the contents not described in the present specification, those skilled in the art that can be technically inferred will be omitted.

In the present specification, that any component is disposed on the "upper (or lower)" of the component or "upper (or below)" of the component means that any component is disposed in contact with the upper surface (or lower surface) of the component. In addition, it may mean that other components may be interposed between the component and any component disposed on (or under) the component.

As used herein, the singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as "consisting of" or "comprising" should not be construed as necessarily including all of the various components described in the specification, and some components may not be included, or additional components. It should be construed as being able to include more elements.

Among the terms used in the present invention, "coverlay" refers to a composite film in which an adhesive is coated on a member layer (mainly, polyimide) to be coated, mainly on the exposed surface of the etched FPCB (Flexible Printed Circuit Board) circuit. It is used to protect and insulate, and "coverlay-integrated electromagnetic wave absorber" refers to an electromagnetic wave absorber that can be provided in an integrated state with a layer (film) having an electromagnetic wave absorption effect.

As shown in a schematic cross-sectional view in FIG. 1, the electromagnetic wave absorber of the present invention includes: a first to-be-coated member layer 10 sequentially stacked; a metal foil layer 20 formed under the first to-be-coated member layer 10; a first adhesive layer 30 formed by coating a first liquid crude liquid containing a heat-resistant resin on a lower portion of the metal foil layer; An MMP layer (Magnetic Metal Powder Layer) 50 formed of a composition including magnetic metal particles and a binder resin under the first adhesive layer 30; a second to-be-coated member layer 60 formed under the MMP layer; and a second adhesive layer 70 formed by coating a second liquid crude liquid containing a heat-resistant and insulating resin on a lower portion of the second to-be-coated member layer, wherein the MMP layer 50 and the first adhesive layer A protective layer 40 for protecting the MMP layer 50 may be additionally disposed between the 30 .

< Protective layer >

As described above, in the electromagnetic wave absorber of the present invention, a protective layer 40 for protecting the MMP layer 50 is additionally disposed between the MMP layer 50 and the first adhesive layer 30, so that in the process Even if the MMP layer is exposed, the resistance to physical and chemical impact may be improved. The protective layer 40 may be formed of one selected from the group consisting of a polyimide (PI) film, a polyethylene terephthalate (PET) film, and a polyethylene naphthalate (PEN) film. The thickness of the protective layer 40 is preferably 2 ~ 7㎛. When the thickness of the protective layer for protecting the MMP layer is less than 2 μm, the protective effect of the MMP layer is difficult to be exhibited, and when it exceeds 7 μm, performance degradation as an electromagnetic wave absorber may occur. In addition, from the viewpoint of exhibiting the electromagnetic wave absorption effect and the electromagnetic wave absorber having an appropriate thickness, the sum of the thicknesses of the protective layer 40 and the MMP layer 50 is preferably 15 to 150 μm, and 25 to 100 μm. more preferably.

<1st and 2nd to-be-coated member layer>

The first member layer 10 and the second member layer 60 of the present invention are each independently formed from the group consisting of a PI (Polyimide) film, a PET (Polyethylene terephthalate) film, and a PEN (Polyethylene naphthalate) film. It may be formed of one selected type.

< Metal foil layer >

The metal foil layer 20 of the present invention is a layer introduced to implement electromagnetic wave shielding and heat dissipation characteristics, and is not limited thereto, but is preferably formed to a thickness of 20 μm. The metal foil layer 20 may include at least one selected from the group consisting of aluminum (Al), copper (Cu), lead (Pb), nickel (Ni) and iron (Fe), and INVAR , and may include an alloy such as SUS.

< MMP layer >

The MMP layer 50 of the present invention is a layer introduced to exhibit electromagnetic wave absorption performance, and may be formed of a composition including magnetic metal particles and a binder resin. More specifically, it is a layer formed by dispersing magnetic metal particles in a binder resin, depending on the degree of electromagnetic wave absorption/shielding function. Based on the total weight of the composition, the content of the magnetic metal particles may be controlled within the range of 30 to 90% by weight. The magnetic metal particles include at least one selected from the group consisting of iron (Fe), silicon (Si), aluminum (Al), chromium (Cr), nickel (Ni), manganese (Mn), and zinc (Zn). and preferably Fe-Si-Al-based alloy (Sendust), Fe-Si-Cr-based alloy, high flux (Highflux), permalloy (Permalloy) alloy, Ni-Zn ferrite (Ferrite) and Mn-Zn ferrite (Ferrite) may be one selected from the group consisting of.

In addition, the binder resin is an epoxy resin, a phenoxy resin, an acrylic resin, a melamine resin, a synthetic rubber resin, a silicone resin, a fluorine resin, a polyamide resin, a polyester resin, a polyethylene resin, a polypropylene resin , and may be at least one selected from the group consisting of polyvinyl chloride-based resins. In this case, the thickness of the MMP layer 50 may be adjusted as needed, and may be formed within a range of 10 to 100 μm, but is not limited thereto.

< First adhesive layer >

The first adhesive layer 30 of the present invention is disposed under the metal foil layer 20 and may be formed by applying a first liquid crude liquid containing a resin having heat resistance. The thickness of the first adhesive layer 30 is preferably 3 to 10 μm. If the thickness of the first adhesive layer 30 is less than 3 μm, the adhesive force between the metal foil layer 20 and the protective layer 40 may be lowered to cause delamination between layers, and if it exceeds 10 μm, the radio wave absorption effect may be reduced. .

The heat-resistant resin included in the first liquid crude liquid may be one selected from a thermosetting resin or a thermoplastic resin. For example, as a thermosetting resin included in the first liquid crude liquid to form the first adhesive layer 30, 10 to 40% by weight of a synthetic rubber resin and 60 to 90% by weight of an epoxy resin and/or a phenoxy resin are mixed. may be used, and a mixture of at least one of a urethane-based resin and an acrylic resin may be used as the thermoplastic resin.

<Second adhesive layer>

The second adhesive layer 70 of the present invention is disposed under the MMP layer 50 and may be formed by applying a second liquid crude liquid containing a resin having heat resistance and insulation properties. The thickness of the second adhesive layer 70 may be 10 to 30 μm. When the thickness of the second adhesive layer 70 is less than 10 μm, there may be a problem of peeling due to reduced adhesive strength with the FPCB, and if it is more than 30 μm, there may be a design problem due to the high thickness of the finished product.

The heat-resistant and insulating resin included in the second liquid crude liquid may be a thermosetting resin. For example, as the thermosetting resin included in the second liquid crude liquid for forming the second adhesive layer 70, 10 to 40% by weight of a synthetic rubber resin, and 60 to 90% by weight of an epoxy resin and/or a phenoxy resin are mixed. may have been In order for the second adhesive layer to have excellent heat resistance, the second liquid crude liquid may further include a flame retardant, and as the flame retardant, alumina oxide (Al ₂ O ₃ ) may be used, but is not limited thereto, and thermosetting resin 100 weight It may be mixed in an amount of 10 to 30 parts by weight based on parts.

< Release substrate layer >

As shown in the schematic cross-sectional view of FIG. 2 , a release substrate layer 80 disposed under the second adhesive layer 70 may be further included. The release base layer 80 may be formed of one selected from the group consisting of a release paper and a release-treated polyethylene terephthalate (PET) film, and the release film serves to protect the electromagnetic wave absorber. .

The method for manufacturing an electromagnetic wave absorber having the structure of FIG. 1 of the present invention may include the following steps.

(a) preparing a first coated product by applying a pressure-sensitive adhesive on the lower portion of the first to-be-coated member layer and then disposing a metal foil layer, followed by lamination;

(b) a second liquid crude liquid containing heat-resistant and insulating resin is applied on the second to-be-coated member layer, coated to form a second adhesive layer with a thickness of 10 to 30 μm, and then laminated with a release base layer to obtain a second preparing a coated product;

(c) forming an MMP layer (Magnetic Metal Powder Layer) by coating a composition containing magnetic metal particles and a binder resin on one surface of the protective layer having a thickness of 2 to 7 μm;

(d) The second coated member layer of the second coated product formed in (b) is placed under the MMP layer formed on one surface of the protective layer in step (c) so that it abuts, and then laminated to form a third coated product preparing a; and

(e) of the first coating product of step (a), a first liquid crude liquid containing a heat-resistant resin is applied to the lower portion of the metal foil layer and coated to form a first adhesive layer with a thickness of 3 to 10 μm, and then 1 After disposing the protective layer of the third coating product prepared in step (d) to contact the lower portion of the adhesive layer, laminating to prepare a fourth coating product.

< Step (a) >

The first coated product to be manufactured in step (a) is a so-called protective film, and is manufactured by disposing a metal foil layer on the first to-be-coated member layer. If it is a method for attaching the metal foil layer to the first to-be-coated member layer, various methods known in the art can be used. For example, after applying or coating a pressure-sensitive adhesive on one surface of the first to-be-coated member layer, the metal foil layer is applied. A method of producing by lamination after placing may be preferably adopted. In this case, the pressure-sensitive adhesive is for attaching or bonding the first to-be-coated member layer and the metal foil layer, and a general adhesive composition used in the art may be used, for example, a siloxane-based polymer pressure-sensitive adhesive or an acrylic polymer pressure-sensitive adhesive. can be used, but is not limited thereto. By applying pressure to the formulation of the pressure-sensitive adhesive as described above, the pressure-sensitive adhesive may be applied or coated to an appropriate thickness for adhering the metal foil layer to the first to-be-coated member layer. The thickness of applying or coating the pressure-sensitive adhesive composition is appropriately adjusted within a range that does not affect the appearance of the metal foil layer and the overall structure while providing sufficient adhesive force necessary for attaching the metal foil layer to the first coated member layer. may be, preferably 5 to 20㎛, more preferably it may be adjusted in the range of 5 ~ 10㎛.

The first to-be-coated member layer may be one selected from the group consisting of a polyimide (PI) film, a polyethylene terephthalate (PET) film, and a polyethylene naphthalate (PEN) film. The metal foil layer may include at least one selected from the group consisting of aluminum (Al), copper (Cu), lead (Pb), nickel (Ni) and iron (Fe), preferably INVAR , and may include an alloy such as SUS.

< Step (b) >

The second coating product to be manufactured in step (b) is a so-called coverlay, and is manufactured by disposing a second adhesive layer on the second coated member layer. In addition, the release base layer may be additionally disposed under the second adhesive layer, the release base layer may be disposed together in step (b), or the release base layer may be disposed on the lower portion of the fourth coated product in step (e). The release base layer may be formed by further comprising the step (f) of forming the base layer.

The second member layer to be coated may be one selected from the group consisting of a polyimide (PI) film, a polyethylene terephthalate (PET) film, and a polyethylene naphthalate (PEN) film. The second adhesive layer may be formed of a second liquid crude liquid containing a thermosetting resin having heat resistance and insulation properties. For example, the thermosetting resin is 10 to 40 wt% of a synthetic rubber resin, an epoxy resin and/or a phenoxy resin. It may be a mixture of 60 to 90% by weight of the resin. The second liquid crude liquid may further include a flame retardant.

By applying pressure to the second liquid crude liquid formulation as described above, the second liquid crude liquid may be applied to or coated with an appropriate thickness on the second to-be-coated member layer. The thickness to which the second liquid crude liquid is applied may be preferably 10 to 30 µm, and if it is less than 10 µm, there may be a problem of peeling due to reduced adhesion with the FPCB, and if it is more than 30 µm, the thickness of the finished product is high There may be design issues.

< Steps (c) and (d) >

The manufacturing target of step (c) is a laminate of a magnetic metal powder layer (MMP) having an electromagnetic wave absorption function and a protective layer for protecting the MMP layer. Specifically, it can be formed by applying or coating a composition for forming an MMP layer on one surface of a thin film protective layer having a thickness of 2 to 7 μm to which a carrier film having a thickness of 20 to 70 μm is attached and lamination. have. The carrier film is removed after the protective layer is formed on the MMP layer. The applied or coated MMP layer may be in either a B-stage (semi-cured) or C-stage (completely cured) state, and may be selected according to the process of the target.

The thickness of the MMP layer prepared in step (c) may be 10 ~ 100㎛, the thickness of the protective layer may be 2 ~ 7㎛, the sum of the thickness of the MMP layer and the protective layer is 15 ~ 150㎛ desirable.

The MMP layer may be formed of a composition including magnetic metal particles and a binder resin, and the magnetic metal particles and the binder resin are the same as those described in <MMP layer> . The protective layer may be formed of one selected from the group consisting of a polyimide (PI) film, a polyethylene terephthalate (PET) film, and a polyethylene naphthalate (PEN) film.

The third coated product to be manufactured in step (d) is placed in contact with the second coated member layer of the second coated product formed in step (b) under the MMP layer formed in step (c), followed by lamination is manufactured by

< Step (e) >

The fourth coating product to be manufactured in step (e) is an electromagnetic wave absorber that is the final manufacturing target of the present invention, and may be applied as an electromagnetic wave shielding sheet of a digitizer of an electronic product.

Specifically, in the first coating product (coating film) prepared in step (a), a first liquid crude liquid containing a heat-resistant resin is applied or coated on the lower portion of the metal foil layer to form a first adhesive layer with a thickness of 3 to 10 μm. Then, the third coating product prepared in step (d) is laminated on the lower portion of the first adhesive layer to prepare a fourth coating product.

The heat-resistant resin included in the first liquid crude liquid may be one selected from a thermosetting resin or a thermoplastic resin. For example, the thermosetting resin included in the first liquid crude liquid may be a mixture of 10 to 40 wt% of a synthetic rubber resin and 60 to 90 wt% of an epoxy-based resin and/or a phenoxy-based resin, and a urethane-based resin as the thermoplastic resin and a mixture of one or more of acrylic resins may be used.

< Step (f) >

In the case where the release base layer is not formed in step (b), in order to manufacture the electromagnetic wave absorber according to the structure of FIG. 2 of the present invention, (f) the release base layer under the fourth coated product in step (e) Forming (80); may further include.

The object described in steps (a) to (f) is the same as the description of the configuration of the electromagnetic wave absorber described in detail with reference to FIG. 1 , and the entire manufacturing method of the electromagnetic wave absorber is a roll to roll process ) can be done through

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and cannot be construed as limiting the present invention in any sense.

[Example]

Example 1

(1) Step: Prepare a 25㎛ PI film (first member to be coated), apply a pressure-sensitive adhesive of polysiloxane resin to the lower portion to a thickness of 10㎛, and then place a 20㎛ metal foil layer of aluminum (Al) component Roll laminated together to form a first coated article.

Step (2): Separately from step (1), prepare a 12.5 μm PI film (second coating member layer), and a liquid crude liquid (second adhesive layer) in which a synthetic rubber resin and an epoxy component are mixed in a 3:7 ratio ) was applied to a thickness of 15 μm, and then a silicone-treated release base layer was placed on PET thereon, and then roll-laminated together to form a second coated product.

Step (3): Separately from the steps (1) and (2), Fe-Si-Al-based magnetic metal particles and acrylic binder resin were added to a 3 μm PET film (protective layer) to which a 50 μm carrier film was attached. An MMP layer of 35 μm was applied by applying a liquid crude solution in which the epoxy component was mixed in a ratio of 7:3. Then, the MMP layer prepared in step (3) is positioned on one side of the PI film (second member to be coated layer) prepared in step (2) on which the second adhesive layer is not formed, and roll lamination is performed together. Then, the carrier film attached to the protective layer was removed to form a third coated product.

Step (4): In the first coating product prepared in step (1), a liquid crude liquid (first adhesive layer) of an acrylic binder resin component is applied to the lower portion of the metal foil layer to a thickness of 5 μm, and then the lower portion of the first adhesive layer The protective layer of the third coated product prepared in step (3) was placed in contact with each other and roll-laminated together to form a fourth coated product, thereby preparing a final electromagnetic wave absorber of Example 1.

Comparative Example 1

Performed in the same manner as in Example 1, except that the steps (3) and (4) are replaced with the following steps (3)' and (4)', and a protective layer for protecting the MMP layer is not provided. A non-electromagnetic wave absorber was prepared.

Step (3)': Fe-Si-Al-based metal magnetic particles and acrylic particles on one side of the PI film (second coated member layer) prepared in step (2) of Example 1, on which the second adhesive layer is not formed. A liquid crude liquid in which a binder resin and an epoxy component were mixed in a 7:3 ratio was applied to apply an MMP layer of 35 μm, and then roll lamination was performed to form a third coating product.

Step (4)': In the first coating product prepared in step (1) of Example 1, a liquid crude liquid (first adhesive layer) of an acrylic binder resin component was applied to the lower portion of the metal foil layer to a thickness of 5 μm, and then The 'MMP layer' of the third coating product prepared in step (3)' is placed in contact with the lower portion of the first adhesive layer and roll-laminated together to form a fourth coated product to prepare the final electromagnetic wave absorber of Comparative Example 1 did.

[Experimental example]

Experimental Example 1: Evaluation of the coefficient of performance

1) Samples for the electromagnetic wave absorber prepared in Example 1 and Comparative Example 1 (size: 100 mm × 100 mm , using a specimen cutter for a product cured at a surface pressure of 50 kgf in a hot press having a temperature of 180 ° C.) Thickness: 35 μm) were prepared, respectively.

2) After installing the impedance measuring instrument in Permeability mode, it was calibrated.

3) After checking the magnetic permeability (μ') value after scanning for 3 cycles at a frequency of 3 MHz, it was converted into a coefficient of performance value by substituting it into the coefficient of performance conversion formula of Equation (1) below, and repeating this three times to derive the average value, It is shown in Table 1 below.

Equation (1): coefficient of performance = (μ'-1) × thickness

Coefficient of performance 1 time Episode 2 3rd time medium Comparative Example 1 7880 7950 7840 7890 Example 1 8105 7867 8003 7992

The coefficient of performance required for each electronic product to which the electromagnetic wave shielding absorber is applied has different values. In Experimental Example 1, the PC model is the standard, and in this case, the coefficient of performance is required to have a value in the range of 6325 to 8645.

As can be seen from Table 1, Comparative Example 1 and Example 1 both satisfy the required value because the coefficient of performance value is similar. Could know.

Experimental Example 2: Gold plating evaluation

1) The adhesive layer (second adhesive layer) side of the coverlay of the electromagnetic wave absorber manufactured in Example 1 and Comparative Example 1 and the FPCB circuit part simulating pattern application were cured at a surface pressure of 50 kgf in a hot press with a temperature of 180 ° C. did it

2) The cured products of Example 1 and Comparative Example 1 were subjected to the following gold plating process according to the following flowchart.

[Gold plating process flow chart]

① Pretreatment process

①-1. Soft Etching Process: A process that gives fine irregularities to the Cu layer inside the FPCB so that Ni/Au components can adhere uniformly during electroplating.

①-2. Sulfuric acid washing process: A process to prevent contamination of plating chemicals and Cu oxidation (use 5g NiSO ₄ per 1 liter of distilled water)

② Plating process

Electroless Ni & Au Plating: A process of sequentially plating Ni (1~3㎛) and Au (0.03~0.05㎛) by substitution reaction of Ni and Au components on the surface of Cu layer in FPCB

3) After completion of the gold plating, it was visually checked whether the liquid penetrated the front of the product, and the results of Comparative Example 1 are shown in FIG. 3 and the results of Example 1 are shown in FIG. 4 .

As can be seen in FIG. 3 , the electromagnetic wave absorber of Comparative Example 1 without a protective layer was oxidized as a result of penetrating the front of the product during gold plating evaluation, and was weak to chemical shock, and it was confirmed that there was a lift. there was. On the other hand, as can be seen from FIG. 4 , the electromagnetic wave absorber of Example 1 having a protective layer did not oxidize on the front surface of the product and a smooth surface was observed. could check

Experimental Example 3: Vibration foreign matter drop-off (Metal magnetic particle drop-off of MMP layer) evaluation

1) A part of the electromagnetic wave absorber of Example 1 and Comparative Example 1 was cut to 80 × 80 mm, the cut surface was sealed, placed in a self-made 100 × 100 mm frame, covered with a cover, and each vibrated with a Vortex Mixer . (Vortex Mixer conditions: 1,000rpm / 30min)

2) Using a loupe of ×10 magnification, the number of dropped magnetic metal particles existing in the frame was checked. This was repeated three times to derive an average value, and is shown in Table 2 below.

Vibration foreign material dropout evaluation (ea) 1 time Episode 2 3rd time medium Comparative Example 1 9 6 13 9.3 Example 1 One 0 0 0.7

As can be seen from Table 2, Comparative Example 1 without a protective layer for protecting the MMP layer was vulnerable to a physical shock such as vibration, and many magnetic particles were dropped, but Example 1 having a protective layer had an MMP layer It was found that the magnetic particles were hardly dropped off because they were protected from physical impact.

As described above, the present invention has been described with reference to the illustrated drawings, but the present invention is not limited by the embodiments and drawings disclosed in the present specification. It is obvious that variations can be made. In addition, even if the effects of the configuration of the present invention are not explicitly described and described while describing the embodiments of the present invention, it is natural that the effects predictable by the configuration should also be recognized.

10: first to-be-coated member layer
20: metal foil layer
30: first adhesive layer
40: protective layer
50: MMP layer
60: second to-be-coated member layer
70: second adhesive layer
80: release base layer

Claims (16)

a first to-be-coated member layer;
a metal foil layer formed under the first to-be-coated member layer;
a first adhesive layer formed by coating a first liquid crude liquid containing a heat-resistant resin on a lower portion of the metal foil layer;
an MMP layer (Magnetic Metal Powder Layer) formed of a composition including magnetic metal particles and a binder resin under the first adhesive layer;
a second to-be-coated member layer formed under the MMP layer; and
a second adhesive layer formed by coating a second liquid crude liquid containing a heat-resistant and insulating resin on a lower portion of the second to-be-coated member layer;
including,
A protective layer for protecting the MMP layer is further disposed between the MMP layer and the first adhesive layer,
The thickness of the protective layer is characterized in that 2 ~ 7㎛,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The protective layer is characterized in that it is formed of one selected from the group consisting of a PI (Polyimide) film, a PET (Polyethylene terephthalate) film, and a PEN (Polyethylene naphthalate) film,
Electromagnetic wave absorber with integrated coverlay structure.
delete According to claim 1,
The sum of the thickness of the protective layer and the MMP layer is characterized in that 15 ~ 150㎛,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The first member layer to be coated and the second member layer to be coated are each independently formed of one selected from the group consisting of a PI (Polyimide) film, a PET (Polyethylene terephthalate) film, and a PEN (Polyethylene naphthalate) film. to do,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The magnetic metal particles include at least one selected from the group consisting of iron (Fe), silicon (Si), aluminum (Al), chromium (Cr), nickel (Ni), manganese (Mn), and zinc (Zn). characterized in that
Electromagnetic wave absorber with integrated coverlay structure.
7. The method of claim 6,
The magnetic metal particles are Fe-Si-Al-based alloy (Sendust), Fe-Si-Cr-based alloy, high flux (Highflux), permalloy (Permalloy) alloy, Ni-Zn ferrite (Ferrite), and Mn-Zn ferrite (Ferrite) characterized in that one selected from the group consisting of,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The binder resin is an epoxy-based resin, a phenoxy-based resin, an acrylic resin, a melamine-based resin, a synthetic rubber resin, a silicone-based resin, a fluorine-based resin, a polyamide-based resin, a polyester-based resin, a polyethylene-based resin, a polypropylene-based resin, and Characterized in that at least one selected from the group consisting of polyvinyl chloride-based resins,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The metal foil layer is characterized in that it comprises at least one selected from the group consisting of aluminum (Al), copper (Cu), lead (Pb), nickel (Ni) and iron (Fe),
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The heat-resistant resin contained in the first liquid crude liquid is characterized in that one selected from the group consisting of a thermosetting resin and a thermoplastic resin,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
The heat-resistant and insulating resin contained in the second liquid crude liquid is a thermosetting resin,
Electromagnetic wave absorber with integrated coverlay structure.
According to claim 1,
Further comprising a release base layer disposed under the second adhesive layer,
The release base layer is characterized in that it is formed of one selected from the group consisting of a release paper and a release-treated PET (Polyethylene terephthalate) film,
Electromagnetic wave absorber with integrated coverlay structure.
(a) preparing a first coated product by applying a pressure-sensitive adhesive on the lower portion of the first to-be-coated member layer and then disposing a metal foil layer, followed by lamination;
(b) a second liquid crude liquid containing heat-resistant and insulating resin is applied on the second to-be-coated member layer, coated to form a second adhesive layer with a thickness of 10 to 30 μm, and then laminated with a release base layer to obtain a second preparing a coated product;
(c) forming an MMP layer (Magnetic Metal Powder Layer) by coating a composition containing magnetic metal particles and a binder resin on one surface of the protective layer having a thickness of 2 to 7 μm;
(d) preparing a third coated product by arranging the second coated member layer of the second coated product in contact with the MMP layer formed on one surface of the protective layer in step (c), and then laminating; and
(e) of the first coating product of step (a), a first liquid crude liquid containing a heat-resistant resin is applied to the lower portion of the metal foil layer and coated to form a first adhesive layer with a thickness of 3 to 10 μm, and then 1 step of laminating the protective layer of the third coating product prepared in step (d) on the lower portion of the adhesive layer and then laminating to prepare a fourth coating product;
characterized in that it comprises,
A method for manufacturing an electromagnetic wave absorber.
14. The method of claim 13,
The sum of the thickness of the protective layer and the MMP layer prepared in step (c) is characterized in that 15 ~ 150㎛,
A method for manufacturing an electromagnetic wave absorber.
14. The method of claim 13,
The protective layer is characterized in that it is formed of one selected from the group consisting of a PI (Polyimide) film, a PET (Polyethylene terephthalate) film, and a PEN (Polyethylene naphthalate) film,
A method for manufacturing an electromagnetic wave absorber.
16. The method according to any one of claims 13 to 15,
The method of manufacturing the electromagnetic wave absorber is characterized in that it is performed in a roll to roll process (roll to roll process),
A method for manufacturing an electromagnetic wave absorber.

Images