KR20160078033A - Preparation method of electromagnetic wave shielding film for flexible printed circuit board - Google Patents

Abstract

The present invention relates to a method of preparing a film of shielding an electromagnetic wave for a flexible printed circuit board. According to the present invention, the invention includes the steps of: (i) forming an insulation layer by coating a thermosetting resin composition for forming an insulation layer on a first surface of a first base film; (ii) laminating a peelable double-layer copper foil comprising a second copper foil, an adhesive layer and a first carrier copper foil on the insulation layer, wherein the first carrier copper foil is detached after coupling the insulation layer and the second copper foil; (iii) forming a conductive adhesive layer by coating a resin composition comprising a conductive filler and a thermosetting resin for forming a conductive adhesive layer on a first surface of a second base film, and drying the same; and (iv) laminating the first base film and the second base film, wherein the second copper foil of the first base film and the conductive adhesive layer of the second base film are arranged so as to be adjoined and compressed through a pressurization process. The present invention can minimize the loss of source materials resulting from repetitively performing multiple coating processes so as to form a plurality of coating layers when the electromagnetic wave shielding film is conventionally manufactured, and can enhance economic feasibility by simplifying the manufacturing process.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing an electromagnetic wave shielding film for a flexible printed circuit board,

TECHNICAL FIELD The present invention relates to a novel shielding film for shielding electromagnetic waves generated in communication devices or communication parts such as electronic parts such as a printed circuit board used for electronic products such as computers, communication devices, printers, mobile phones, video cameras, And a manufacturing method thereof.

In general, there is an increasing demand for miniaturization, planarization, and high functionality of electronic devices. In order to meet these demands, complex electromagnetic noise is generated by implementing components in different frequency ranges in the same electronic device, and it is becoming difficult to take measures against such complex electromagnetic noise. On the other hand, data transmission cables are also increasingly demanding for thinner and less electromagnetic noise emissions. In the case of transmitting a large amount of data, an error occurs in the data due to the interference of the data due to electromagnetic noise, and data is frequently lost.

In order to satisfy electromagnetic compatibility, it is necessary to reduce the electromagnetic noise generated from various electric / electronic and communication devices as much as possible and to reduce the electromagnetic susceptibility to the external electromagnetic environment so as to enhance the electromagnetic wave resistance of the device itself. The most important characteristics required for electromagnetic compatibility products to be inserted into various electrical, electronic and communication devices are that electromagnetic shielding ratio and absorption rate must be large, and electromagnetic compatibility products should be small and thin according to the trend of short and light equipment.

As a countermeasure for solving the electromagnetic noise problem described above, a shielding film in which a metal layer and a conductive adhesive layer are sequentially provided on one or more insulating layers is often used. Such a shielding film is generally produced by repeating a coating process at least twice to form a plurality of coating layers such as an insulating layer, a metal layer, a conductive adhesive layer and the like on a base film. When such a secondary multi-coating is performed, the loss of the primary coated raw material is essentially caused, which leads to a problem that the yield and physical properties of the final product are lowered.

The present inventors have devised in order to solve the above-mentioned problems. In the prior art, when a multi-coating process is repeatedly performed to form a plurality of coating layers at the time of manufacturing an electromagnetic wave shielding film, And the manufacturing process can be simplified.

Particularly, in the present invention, by using the separable double-layer copper foil produced by the continuous process at the time of manufacturing the electromagnetic wave shielding film containing a metal layer of a copper material, not only the above- A part of the manufacturing process of the existing electromagnetic wave shielding film can be shortened and the productivity can be improved by interlocking the process line.

Accordingly, it is an object of the present invention to provide a novel method for manufacturing an electromagnetic wave shielding film which can simultaneously minimize the loss of material, simplify the manufacturing process, and improve the productivity.

In order to achieve the above object, the present invention provides a method of manufacturing a semiconductor device, comprising the steps of: (i) forming an insulating layer by coating a first surface of a first base film with a thermosetting resin composition for forming an insulating layer; (ii) depositing a peelable double-layer copper foil comprising a second copper foil, a pressure-sensitive adhesive layer and a carrier first copper foil on the insulating layer, bonding the insulating layer and the second copper foil, step; (iii) coating a resin composition for forming a conductive adhesive layer including a conductive filler and a thermosetting resin on a first side of a second base film, and then drying to form a conductive adhesive layer; And (iv) depositing a first base film and a second base film, placing the second base film of the first base film and the conductive adhesive layer of the second base film in contact with each other, and then pressing them through a pressing process And a method for producing the electromagnetic wave shielding film.

Preferably, the insulating layer formed in step (i) is semi-cured (B-stage), and the conductive adhesive layer formed in step (iii) is semi-cured.

According to a preferred embodiment of the present invention, in the separable double-layered copper foil of step (ii), the thickness of the second copper foil is in the range of 1 to 12 占 퐉, and the thickness of the first copper foil is larger than that of the second copper foil.

According to another preferred embodiment of the present invention, it is preferable that the second copper of the step (ii) is attached on the first side of the insulating layer and used as a metal layer of the electromagnetic wave shielding film.

According to another preferred embodiment of the present invention, it is preferable that the first base film and the second base film are each a release-treated film. Further, it is preferable that the first base film disposed on the insulating layer side is matted, corona treated, or contains beads inside.

In the present invention, in manufacturing a conventional electromagnetic wave shielding film, it is possible not only to minimize the loss of material caused by repeatedly performing the coating process to form a plurality of coating layers, but also to improve the economical efficiency by simplifying the manufacturing process.

In addition, the existing copper foil production line and the coating process line can be linked with each other to enable in-line continuous process, as well as to shorten the manufacturing process of existing electromagnetic wave shielding film, thereby enhancing productivity.

1 is a view showing a manufacturing process of an electromagnetic wave shielding film according to an embodiment of the present invention.
2 is a view showing a first lamination process of an insulating layer and a separable dual-layer copper foil in the process of manufacturing the electromagnetic wave shielding film of the present invention.
3 is a schematic diagram showing the configuration of an electromagnetic wave shielding film according to an embodiment of the present invention.
4 is an image of the separable dual-layer copper foil used in the present invention.
Fig. 5 shows a form of the coupon manufactured for evaluating the shielding rate of the electromagnetic wave shielding film.
6 is a view showing a method of evaluating chemical resistance of an electromagnetic wave shielding film and evaluation criteria.
Description of the Related Art
100: electromagnetic wave shielding film for forming a flexible circuit board
10: first base film 20: insulating layer
30: conductive adhesive layer 40: copper metal layer
50: second base film

Hereinafter, the present invention will be described in detail.

An electromagnetic wave shielding film refers to a film which is laminated on the outermost portion (coverlay portion) of a flexible printed circuit board for electromagnetic interference (EMI) noise shielding. These electromagnetic wave shielding films are required to have various physical properties, and they are required to have excellent electromagnetic wave shielding effect, bending property, excellent thermal stability, chemical resistance, abrasion resistance, low resistance change and the like.

As a conventional electromagnetic wave shielding film, a film in which a metal layer and a conductive adhesive layer are sequentially provided on one or more insulating layers is used. Such an electromagnetic wave shielding film must be repeatedly subjected to a multi-coating process in order to form a plurality of layers, which leads to the loss of the primary coated raw material and deteriorates the yield and physical properties of the final product.

Accordingly, in the present invention, a multi-coating process which is repeatedly performed to form the plurality of coating layers described above is first coated and then laminated. By changing the manufacturing process as described above, it is possible not only to minimize the loss of the primary coated raw material (20 to 100 m), but also to improve the production speed of the electromagnetic shielding manufacturing process due to the introduction of the lamination process.

Particularly, the present invention aims at examining overall fairness according to application of a metal layer for high frequency material development.

At this time, when a peelable double layer copper foil produced by a continuous process is used as the metal layer in manufacturing an electromagnetic wave shielding film including a metal layer of a copper material, the above-described material loss can be minimized and the manufacturing process can be simplified. In addition, the existing copper foil production line and the coating process line can be interlocked with each other to enable in-line continuous process. As described above, when the copper foil production line is interlocked with the existing copper foil production line, it is preferable to interlock the insulating layer formation process. Further, by interlocking with the copper foil production line, it is possible to shorten the manufacturing process of a part of the existing electromagnetic wave shielding film, for example, the additional surface treatment (the mat treatment) of the copper foil, thereby improving the productivity.

In addition, since the conductive adhesive layer can be configured for each unit process, an independent manufacturing line constituting the conductive adhesive layer can be separately formed. Therefore, facility investment can be minimized and economic efficiency can be improved.

≪ Method for producing electromagnetic wave shielding film for forming flexible printed circuit board >

Hereinafter, a method of manufacturing an electromagnetic wave shielding film for forming a flexible printed circuit board according to the present invention will be described. However, the present invention is not limited to the following production methods, and the steps of each process may be modified or optionally mixed as required.

(I) forming an insulating layer on the first surface of the first base film by coating a thermosetting resin composition for forming an insulating layer on the first surface of the first base film; (ii) depositing a peelable double-layer copper foil comprising a second copper foil, a pressure-sensitive adhesive layer and a carrier first copper foil on the insulating layer, bonding the insulating layer and the second copper foil, step; (iii) coating a resin composition for forming a conductive adhesive layer including a conductive filler and a thermosetting resin on a first side of a second base film, and then drying to form a conductive adhesive layer; And (iv) depositing a first base film and a second base film, placing the second base film of the first base film and the conductive adhesive layer of the second base film in contact with each other, and then pressing them through a pressing process .

Fig. 1 is an operation flow chart for manufacturing the electromagnetic wave shielding film of the present invention. Hereinafter, the manufacturing method will be described separately for each step with reference to FIG.

First, 1) a resin composition for forming an insulating layer is coated on a first surface of a first base film to form an insulating layer.

The resin composition for forming an insulating layer may be formed by curing a thermosetting composition comprising a conventional thermosetting resin and a curing agent known in the art. The insulating layer formed at this time may be in a B-stage state or a fully cured state (C-stage), preferably in a B-stage state.

Non-limiting examples of thermosetting resins usable in the present invention include epoxy resin, phenol resin, vegetable oil-modified phenol resin, xylene resin, guanamine resin, diallyl phthalate resin, vinyl ester resin, unsaturated polyester resin, furan resin, A polyimide resin, a polyurethane resin, a cyanate resin, a maleimide resin, and a benzocyclobutene resin. Preferably, it is an epoxy resin, a phenol resin or a vegetable rubidic phenolic resin. The double epoxy resin is preferred because of its excellent reactivity and heat resistance.

The epoxy resin may be any conventional epoxy resin known in the art, and it is preferable that two or more epoxy groups are present in one molecule.

Examples of usable epoxy resins include, but are not limited to, bisphenol A type / F type / S type resin, novolak type epoxy resin, alkylphenol novolak type epoxy resin, biphenyl type, aralkyl type, naphthol Naphthol type, dicyclopentadiene type, or mixed form thereof.

More specific examples thereof include epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, anthracene epoxy resin, biphenyl type epoxy resin, Cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol S novolak type epoxy resin, biphenyl novolac type epoxy resin, naphthol novolak type epoxy resin, naphthol phenol coaxial novolak type epoxy resin , Naphthol cholizole co-novolak type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, triphenyl methane type epoxy resin, tetraphenyl ethane type epoxy resin, dicyclopentadiene phenol addition reaction type epoxy resin, phenol aral A quarternary epoxy resin, a polyfunctional phenol resin, a naphthol aralkyl type epoxy resin There is. At this time, the above-mentioned epoxy resin may be used alone, or two or more epoxy resins may be used in combination.

In the present invention, conventional curing agents known in the art can be used without limitation, and can be appropriately selected depending on the type of epoxy resin to be used. Non-limiting examples of usable curing agents include phenol-based, anhydride-based, dicyanamide-based, and curing agents. Of these, phenolic curing agents are preferred because they can further improve heat resistance and adhesiveness.

Non-limiting examples of the phenolic curing agent include phenol novolak, cresol novolac, bisphenol A novolac, naphthalene type, etc. These may be used alone or in combination of two or more.

Meanwhile, the insulating layer according to the present invention may further include a conventional electrically nonconductive filler known in the art to effectively exhibit the mechanical properties and the low resistance change of the final product.

The electrically nonconductive filler may be an organic filler, an inorganic filler, or a mixture thereof. For example, it is preferable to use electrically nonconductive carbon black, black dye, or a mixture of at least one thereof.

The content of the electrically nonconductive filler can be appropriately adjusted in consideration of the mechanical properties of the insulating layer, the change in resistance, and other physical properties of the insulating layer, for example, 0.5 to 5 parts by weight based on 100 parts by weight of the insulating layer .

Since the insulating layer of the present invention preferably contains a flame retardant, it is preferable that the above-mentioned thermosetting resin and the curing agent component contain a flame retardant and cure.

As the flame retardant, conventional flame retardants known in the art may be used without limitation, but organic phosphorous flame retardants, organic nitrogen-containing compounds, nitrogen compounds, silicone flame retardants, metal hydroxides and other flame retardants are preferred.

Specific examples of the phosphorus compound-based flame retardant include triaryl isopropyl phosphate, tris (3-hydroxypropyl) phosphine oxide, 1,3-phenylene-naphthacylenyl phosphate, ester compounds based on condensation products of phenol condensates, phosphate complexes and aromatic condensed esters of polymerization product (polymerization degree 1 to 3) of p-hydroxyphenyl) propane trichlorophosphine oxide, or polyphosphoric acid ammonium, Polyphosphoric acid ammonium acid, butyl acid phosphate, butoxyethyl acid phosphate, melamine phosphate, or red phosphorus.

Specific examples of the nitrogen compound-based flame retardant include melamine derivatives such as melamine, melamine cyanurate, melam, merem, and melon. The above-mentioned flame retardants may be used singly or in combination of two or more.

The content of the flame retardant is not particularly limited and can be appropriately adjusted within the conventional range known in the art.

The first base film to be coated with the composition for forming an insulating layer may be a conventional plastic film known in the art without limitation, and examples thereof include polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate Polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer, polyvinyl alcohol film, polyethylene terephthalate film, A polystyrene film, a polyether sulfone film, a polyetherimide film, a polyimide film, a fluororesin film, a polyamide film, a polyimide film, a polystyrene film, , An acrylic resin film, a norbornene resin film, a cycloolefin resin There are such names. These plastic films may be either transparent or semitransparent, and may be colored or non-colored, and may be appropriately selected depending on the application.

When a polyimide (PI) film is used as the release film, the flexible film can be sequentially laminated on a flexible printed circuit board (FPCB), followed by hot pressing at about 220 ° C. In the case of a polyethylene terephthalate (PET) film, a low-temperature press of about 180 占 폚 may be used. Or deformity maps are available.

It is preferable that the first base film and the second base film are each treated with a releasing agent, and a release layer is disposed between the first base film and the insulating layer, and between the second base film and the conductive adhesive layer.

In the present invention, in the case where the resin composition for forming an insulating layer is applied on the first base film, the resin composition for forming the insulating layer may be applied to the first base film by a roll coater, a bar coater, a comer coater, a blade coater, a lip coater, a rod coater, a squeeze coater, A thermosetting resin composition may be coated on a substrate by a coater, a gravure coater, a spray coater, or the like and dried at a temperature of 50 to 130 ° C for 1 to 30 minutes.

Examples of the organic solvent usable in preparing the resin composition for forming the insulating resin layer include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate , And carbitol acetate; carbohydrates such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide; dimethylacetamide; and N-methylpyrrolidone. The organic solvents may be used alone or in combination of two or more.

2) A peelable double layer copper foil is laminated on the first surface of the insulating layer, and then the insulating layer and the second copper foil are bonded to each other in the separated double-layer copper foil and the carrier first copper foil is detached.

The separable dual-layer copper foil usable in the present invention may comprise a carrier copper foil, a release laver, and a second copper foil.

In the separable double-layered copper foil, the carrier first copper and the second copper each have a metal thin film form composed of a copper material.

Here, the carrier first copper protects the relatively thin copper foil and physically supports it. And then easily separates from the second copper foil.

The second copper foil is attached on the first surface of the insulating layer to serve as a metal layer of the electromagnetic wave shielding film, for example, a copper foil layer.

Since the carrier first copper and the second copper contain an adhesive layer therebetween, they have heat resistance and anti-corrosiveness. In particular, due to the adhesive component included in the adhesive layer, the first copper foil and the second copper foil can be easily separated from each other without physical damage during the desorption process.

In order to protect the second copper foil, the thickness of the carrier first copper foil is preferably larger than that of the second copper foil. For example, the thickness of the second copper foil is in the range of 1 to 12 mu m, and the thickness of the first copper foil is not particularly limited as long as it is larger than the second copper foil.

In the present invention, it is preferable to use a copper foil formed by a conventional continuous in-line process as the separable double-layered copper foil or the carrier first and second copper foils included therein. In this case, the coating process line can be linked to the copper foil production line to make it in-line capable of being continuously produced, thereby shortening the additional surface treatment of the copper foil, for example, a mat treatment process .

On the other hand, Figs. 1 and 2 are diagrams showing a step of lamination, desorption and primary lamination of an insulating layer and a separable double-layer copper foil in the process of manufacturing the electromagnetic wave shielding film of the present invention.

In a preferred example of the step (ii), the separable double-layer copper foil is laminated on the first surface of the insulating layer, the insulating layer and the second copper foil are brought into contact with each other, and the carrier copper foil and the adhesive layer are then detached, do.

For example, referring to FIG. 1, after a dielectric layer is formed on a first surface of a first base film, a separable dual-layer copper foil, which is separately manufactured in a B-stage state, The first copper-adhesive layer-second copper], and thereafter removing the carrier copper foil.

2, an insulating layer is formed on a copper foil by a continuous process with a copper foil production line, followed by drying in a semi-cured state, and then the carrier copper foil is removed. In both of the above processes, it is preferable that the insulating layer proceeds in a semi-hardened (B-stage) state.

After the above two steps, a structure in which an insulating layer and a second copper foil layer are sequentially laminated is formed on the first base film.

3) A composition for forming a conductive adhesive layer is coated on the first side of the second base film and dried to form a conductive adhesive layer.

The second base film may also be made of any conventional plastic film known in the art without limitation, and a mold release map can be used. The second base film may be the same as or different from the first base film.

The composition for forming a conductive adhesive layer to be coated on the second base film may be formed by curing a thermosetting composition comprising a conventional thermosetting resin component and an electrically conductive filler known in the art. The conductive adhesive layer formed at this time is desirably semi-cured (B-stage) in consideration of the adhesion and adhesion of the first base film to the second copper foil in the subsequent step.

The conductive filler may be any conventional conductive filler known to those skilled in the art. For example, it may be a copper filler or a nickel filler coated with Ag, Cu, Ni, Al or Ag. A polymer filler, a filler obtained by metal plating on a resin ball or a glass bead, a mixture thereof, or the like.

Here, silver (Ag) is expensive, copper (Cu) is insufficient in reliability of heat resistance, and aluminum (Al) Ni) filler is preferably used.

The content of the conductive filler is not particularly limited as long as it exhibits an electromagnetic wave shielding effect, and may be, for example, 30 to 70 parts by weight based on 100 parts by weight of the composition for forming a conductive adhesive.

Resins usable in the conductive adhesive layer of the present invention may be any of conventional thermosetting resins known in the art. For example, the same component as the thermosetting resin constituting the above-described insulating layer. At this time, it may further include a curing agent, a flame retardant, or both, and these components may also be the same as or different from the components constituting the above-described insulating layer.

In the present invention, in the case where the resin composition for forming a conductive adhesive layer is applied onto the second base film, for example, a roll coater, a bar coater, a comer coater, a blade coater, a lip coater, a rod coater, a squeeze coater, a reverse coater, A thermosetting resin composition may be coated on a substrate by a coater, a gravure coater, a spray coater, or the like and dried at a temperature of 50 to 130 ° C for 1 to 30 minutes.

4) The first base film and the second base film are laminated, and the second copper foil of the first base film and the conductive adhesive layer of the second base film are arranged so as to be in contact with each other, followed by compression through a pressing process.

In the present invention, the conditions of the pressing process can be appropriately adjusted within the conventional range known in the art. Thermocompression Lami. The conditions for the process (roll-to-roll) are not particularly limited, but may be performed at a temperature of from room temperature to 130 ° C, a pressure of 3 to 50 kgf / cm ² , and a compression rate of 3 m / min to 30 m / min.

At this time, the first base film in which the sheet-like first base film, the insulating layer, and the second copper film are sequentially laminated and the second base film on which the conductive adhesive layer is formed may be rolled up into rolls and laminated continuously, It is also possible to perform the lamination after cutting both rolls of the sheet.

After the above step, the above-mentioned electromagnetic wave shielding film can be slit to an appropriate size.

The electromagnetic wave shielding film of the present invention manufactured as described above may have the structure shown in FIG.

≪ Electromagnetic wave shielding film for forming flexible printed circuit board (FPCB)

The present invention also provides an electromagnetic wave shielding film produced by the above-described method.

Hereinafter, an electromagnetic wave shielding film for forming a flexible printed circuit board (FPCB) according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view showing a preferred embodiment of the electromagnetic wave shielding film according to the present invention.

The electromagnetic wave shielding film of the present invention can be roughly classified into an insulating layer 10 and a conductive layer, wherein the conductive layer includes a copper foil layer 40 and a conductive adhesive layer 30.

3, the electromagnetic wave shielding film 100 includes a first base film 10, an insulating layer 20, a copper foil layer 40 on one side of the insulating layer, a conductive adhesive layer 30, And a second base film 50, which have a structure in which they are sequentially laminated. At this time, the first base film 10 and the second base film 50 may each be a release film subjected to a release treatment.

≪ Insulating layer &

In the electromagnetic wave shielding film of the present invention, the insulating layer is finally present at the outermost position of the film, and exhibits thermal stability, chemical resistance, scratch resistance, etc. in addition to the bending property of the film while giving mechanical strength to the electromagnetic wave shielding film .

The insulating layer may be formed by curing a thermosetting composition including a conventional thermosetting resin and a curing agent known in the art as a coating layer or a film.

The thickness of the insulating layer can be appropriately adjusted in consideration of handling property of the film, physical rigidity, thinning of the substrate, and the like. For example, in the range of 5 to 20 mu m, and preferably in the range of 5 to 7 mu m.

The insulating layer according to the present invention can exhibit bendability equivalent to that of the conventional flexible copper clad laminate (FCCL), and can exhibit scratch resistance and excellent chemical resistance not less than 1H.

≪ Conductive adhesive layer &

In the electromagnetic wave shielding film of the present invention, the conductive adhesive layer includes a conductive material and exhibits an electromagnetic wave shielding effect, and exhibits an adhesive force, a bending property, and an interlaminar adhesive force. Further, since the function of fixing the electromagnetic wave shielding film to the adherend is also provided, it can be stably connected to the electric circuit of the printed circuit board when attached to the flexible printed circuit board (FPCB) It is possible to effectively prevent intrusion into the printed circuit board.

The conductive adhesive layer includes a thermosetting resin component and a conductive filler in order to exhibit an adhesive force and an electromagnetic wave shielding effect.

The thickness of the conductive adhesive layer can be appropriately adjusted in consideration of electromagnetic wave shielding force, bending property, adhesive force, interlayer adhesive force, and the like of the film. For example, in the range of 2 to 30 mu m, and preferably in the range of 3 to 15 mu m.

According to an embodiment of the present invention, the total thickness of the conductive layer combined with the metal layer and the conductive adhesive layer can be appropriately adjusted according to the use for flexibilization or the application for high-stage difference. For example, the conductive layer may have a thickness in the range of 3 to 5 占 퐉 when it is used in an ultra-bending mode, and may be in the range of 13 to 15 占 퐉 when it is used for high-end applications.

In addition, the conductive layer according to the present invention can secure a high adhesive force with a cover printed on a flexible printed circuit board (FPCB), for example, 1.0 kgf / cm or more. The bendability of the conductive layer may be equivalent to that of the conventional flexible copper clad laminate (FCCL). In addition, the electromagnetic wave shielding force of the conductive layer may be 60 dB or more.

≪ Copper foil layer &

In the electromagnetic wave-shielding film of the present invention, the copper foil layer is formed on one side of the insulating layer, and includes a conductive material to exert an electromagnetic wave shielding effect.

The copper foil layer may be any conventional copper foil known in the art without limitation, including all copper foils produced by the rolling and electrolytic methods. Preferably a copper foil formed by a continuous in-line process. Here, the copper foil may be rust-proofed to prevent the surface from being oxidized and corroded.

The thickness of the copper foil layer can be appropriately adjusted in consideration of the electromagnetic shielding force of the film. For example, in the range of 1 to 12 mu m, and preferably in the range of 1 to 6 mu m.

According to a preferred embodiment of the present invention, the electromagnetic wave shielding film may include a release film on the insulating layer and the conductive adhesive layer, respectively.

In the present invention, the first release film and the second release film are respectively disposed on the insulating layer and the conductive adhesive layer. At this time, in consideration of the bonding process between the flexible printed circuit board and the electromagnetic shielding film, it is preferable that the interlayer adhesive force between the insulating layer and the first release film is adjusted to be higher than the interlayer adhesion force between the conductive adhesive layer and the second release film.

To this end, the first release film disposed on the insulating layer is subjected to surface treatment by an oxidation method, an irregularization method or the like on one surface or both surfaces, if necessary, for the purpose of improving adhesion with an insulating layer provided on the surface of the first release film can do. Examples of the oxidation method include a corona discharge treatment, a plasma treatment, a chromic acid treatment (wet), a flame treatment, a hot air treatment, an ozone / ultraviolet ray irradiation treatment and the like. a sand blast method, a solvent treatment method, and the like. These surface treatment methods are appropriately selected depending on the kind of the base film, but generally mat treatment and corona discharge treatment are preferable in terms of effect and operability. Or beads inside the release film.

The thickness of the release film is not particularly limited, but is adjustable within the conventional range known in the art. The release film may be disposed on the insulating layer and the conductive adhesive layer. The thickness of the upper release film (first release film) contacting the insulation layer may be in the range of 50 to 75 mu m, and the lower release film (Second release film) may range from 75 to 150 mu m.

According to another example of the present invention, a release layer may be included on the above-mentioned release film. This release layer has a function of easily separating the release layer and the conductive adhesive layer from each other so that the insulating layer and the conductive adhesive layer can maintain their shape without being damaged. Here, the release layer may be a commonly used film-type release material.

The component of the releasing agent used in the releasing layer is not particularly limited, and conventional releasing agent components known in the art can be used. Non-limiting examples thereof include epoxy-based releasing agents, releasing agents comprising fluororesins, silicone-based releasing agents, alkyd resin-based releasing agents, and water-soluble polymers. The thickness of the release layer is not particularly limited and the interlaminar adhesion between the insulation layer and the first release film is adjusted to be higher than the interlaminar adhesion between the conductive adhesive layer and the second release film in consideration of the bonding process between the printed circuit board and the electromagnetic shielding film . The releasability of the release film may range from 50 to 500 gf / inch. As an example, the release force of the first release film may range from 50 to 200 gf / inch, and the release force of the second release film may range from 30 to 50 gf / inch

The method for forming the releasing layer is not particularly limited, and known methods such as hot press, heat roll laminate, extrusion laminate, application of a coating liquid, and drying can be employed.

In addition, in the present invention, the electromagnetic wave shielding film may be laminated on a printed circuit board, preferably a cover layer of a flexible printed circuit board (FPCB), and then bonded.

At this time, the bonding between the flexible printed circuit board and the electromagnetic wave shielding film can be performed by a conventional method known in the art. For example, it may be bonded by an adhesive, or may be bonded in a non-adhesive form without using an adhesive.

In one preferred embodiment of the manufacturing process of the EMI shielding film for a flexible printed circuit board, for example, (I) an electromagnetic wave shielding film is laminated on a flexible printed circuit board cover layer, the first base film provided on the conductive adhesive layer side is removed Stacking the exposed conductive adhesive layer on the coverlay of the flexible printed circuit board and thermocompression bonding; And (II) removing the second base film located at the top of the squeeze.

The flexible printed circuit board may be a flexible copper clad laminate (FCCL) having a cover layer, for example, a copper foil layer and a cover layer sequentially stacked on a polyimide (PI). The printed circuit board in the present invention refers to a printed circuit board laminated in a single layer or two to three or more layers by a plating through hole method, a build-up method, or the like, and may be a sectional shape or a double-sided type.

The conditions for the thermocompression bonding step are not particularly limited. For example, the thermocompression bonding step may be performed at a temperature of 150 to 170 DEG C, a pressure of 30 to 80 kgf / cm < ² >

In the present invention, excellent electromagnetic wave shielding performance can be exhibited by bonding the electromagnetic wave shielding film on the flexible printed circuit board as described above.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the scope of the present invention is not limited by the following Examples and Experimental Examples.

[Example 1]

1-1. Preparation of insulating layer coating liquid

9.1 wt% of a halogen-free flame-retardant epoxy resin (National Kagaku KDP555) as a thermosetting resin, 8.1 wt% of a bisphenol A type epoxy resin (Dow DER383), 3.5 wt% of a low dielectric epoxy resin (Nippon XD1000) 4.8% by weight of a phosphorus flame retardant (Otsuka Chemical SPB-100), 24.2% by weight of a rubber (KKNB 40H) as a thermoplastic resin, 0.02% by weight of polyvinyl butyral 12.1 wt% of resin (Unochem KS23Z), 10.7 wt% of dicyanamide as a latent curing agent, 0.6 wt% of an imidazole derivative (Ildong Chemical 2E4MZ) as a catalyst type curing agent, 9.8 wt% of methylcellosolve as a solvent, Layer coating solution.

1-2. Conductive adhesive layer coating solution preparation

, 5.5 wt% of a halogen-free flame-retardant epoxy resin (National Kagaku KDP555), 4.9 wt% of a bisphenol A type epoxy resin (Dow DER383), 2.1 wt% of a low dielectric epoxy resin (Nippon XD1000), a bisphenol novolac epoxy resin (KPBN 110), 48.6% by weight of Dendrite powder (CuGe10 CHL5 UF manufactured by GGP) coated with copper as a conductive filler, 21.9% by weight of rubber (KKNB 40H) as a thermoplastic resin, 0.3% by weight of an imidazole derivative (Ildong Chemical 2E4MZ) as a catalyst type curing agent, and 4.9% by weight of propylene glycol monomethyl ether acetate as a solvent were mixed and dissolved to prepare a coating solution for forming a conductive adhesive layer.

1-3. Manufacture of electromagnetic wave shielding film

An insulation layer was formed on the first side of the prepared first base film by micrograye coating and dried at 130 ° C for 3 minutes and 30 seconds to form a semi-cured state of 5 to 6 μm Was formed.

Layered copper foil on the insulating layer of the first base film using a peelable double layer copper foil (electrolytic copper foil (1 탆) + separating layer + carrier copper foil (35 탆), Olin Brass (1 탆 electrolytic copper foil) After bonding the second copper foil, the carrier first copper foil was detached.

The conductive adhesive layer coating composition prepared in 1-2 above was coated on the first side of the prepared second base film with a comma coating to form a conductive adhesive layer and dried at 130 캜 for 3 minutes and 30 seconds to form a 4 to 5 탆 semi-cured Conductive adhesive layer was formed.

The second copper foil formed on the first base film and the conductive adhesive layer formed on the second base film are arranged so as to be in contact with each other and then pressed together through a heating and pressing process at 80 DEG C and 10 kgf / cm to form an electromagnetic wave shielding film for a flexible printed circuit board .

At this time, an image of the separable dual-layer copper foil (Olin Brass (1 탆) electrolytic copper foil) is shown in FIG.

[Examples 2 to 4]

An electromagnetic wave shielding film for a flexible printed circuit board was produced in the same manner as in Example 1, except that the thickness of the electrolytic copper foil of the separable double-layer copper foil was changed as shown in Table 1 below.

In Examples 2 to 3, a 2 μm electrolytic copper foil (Mitsui (Japan), 2 μm electrolytic copper foil) and a 3 μm electrolytic copper foil (Mitsui (Japan), 3 μm electrolytic copper foil) A 6 탆 rolled copper foil (Mitsui (Japan), 6 탆 electrolytic copper foil) composed of a single copper layer was used.

[Example 5]

An insulating layer was formed on the first side of the prepared first substrate film by micrograye coating and dried at 130 ° C for 3 minutes and 30 seconds to form a coating layer having a radius of 5 to 6 μm Thereby forming an insulating layer in an oxidized state.

The conductive adhesive layer composition prepared in Example 1-2 was coated on the first side of the prepared second base film with a comma coating to form a conductive adhesive layer and dried at 130 캜 for 3 minutes and 30 seconds to form a conductive semi-cured state of 14 to 15 탆 Layer.

Layered copper foil on the insulating layer of the first base film using a peelable double layer copper foil (electrolytic copper foil (1 탆) + separating layer + carrier copper foil (35 탆), Olin Brass (1 탆 electrolytic copper foil) After bonding the second copper foil, the carrier first copper foil was detached.

Thereafter, the second copper foil formed on the first base film and the conductive adhesive layer formed on the second base film are arranged so as to be in contact with each other, and then they are pressed together through a heating and pressing process at 80 캜 and 10 kgf / cm, A film was prepared.

[Examples 6 to 8]

An electromagnetic wave shielding film for a flexible printed circuit board was produced in the same manner as in Example 5 except that the thickness of the electrolytic copper foil of the separable double layer copper foil was changed as shown in Table 1 below.

In Examples 6 to 7, a 2 탆 electrolytic copper foil (Mitsui Sun, 2 탆 electrolytic copper foil) and a 3 탆 electrolytic copper foil (Mitsui Sun, 3 탆 electrolytic copper foil) A 6 탆 rolled copper foil (Mitsui (Japan), 6 탆 electrolytic copper foil) composed of a single copper layer was used.

[Comparative Example 1]

An electromagnetic wave shielding film for a flexible printed circuit board was produced in the same manner as in Example 1, except that the separable double layer copper foil was not used.

More specifically, the insulating layer formed on the first base film and the conductive adhesive layer formed on the second base film were placed so as to be in contact with each other, and then pressed through a heating and pressing process under the conditions of 80 캜 and 10 kgf / cm, A film was prepared.

[Comparative Example 2]

An electromagnetic wave shielding film for a flexible printed circuit board was produced in the same manner as in Example 5, except that the separable double layer copper foil was not used.

More specifically, the insulating layer formed on the first base film and the conductive adhesive layer formed on the second base film were arranged so as to be in contact with each other, and then pressed through a heating and pressing process under the conditions of 80 캜 and 10 kgf / cm, A film was prepared.

[Evaluation example] Evaluation of electromagnetic wave shielding film

The following properties of the electromagnetic wave shielding films prepared in Examples 1 to 8 and Comparative Examples 1 and 2 were evaluated, respectively, and the results are shown in Table 1 below.

1) Adhesion

After the prepared second base film was removed, the conductive adhesive layer was disposed so as to be in contact with a 50 탆 PI film (SKC Kolon), laminated at 80 to 100 캜, and then the upper first base film was removed.

To form the supporting layer of the laminated adhesive force evaluation coupon, a bonding sheet and a prepreg impregnated with a resin in a glass fiber matrix were laminated on the bottom of a 50 mu m PI film, and a bonding sheet and a 25 mu m PI film (SKC Kolon) was laminated and subjected to a pressing process at a temperature of 150 ° C for 60 minutes under a pressure of 35 kgf per unit area to completely cure the insulating layer and the conductive adhesive layer.

The fully cured coupon was measured for a 90 degree (vertical) adhesive force (kgf / cm) for the PI film at a pulling rate of 50 mm / min.

2) Heat Resistance Characteristics (Solder Deeping)

After the second base film of the prepared electromagnetic wave shielding film was removed, the 25 μm-thick PI film (SKC Kolon) was placed so as to be in contact with the conductive adhesive layer, followed by compression at 150 ° C. for 60 minutes under a pressure of 35 kgf per unit area, Completely cured and the upper first base film was removed.

The electromagnetic wave shielding film from which the upper first base film was removed was immersed in a 300 ° C water bath for 10 seconds to observe the appearance of defects such as lifting and cracking of the electromagnetic wave shielding film and color change of the insulating layer. In this case, it was judged as NG when the appearance defects such as lifting and cracking occurred, and when the appearance defects such as lifting and cracking were not found, it was judged as Pass.

3) Evaluation of chemical resistance in insulating layer:

Evaluation of Heat Resistance Characteristic The coupon was produced by the lamination and compression process in the same manner as the coupon manufacturing method, and the upper first base film was removed. An electromagnetic wave shielding film from which the upper first base film was removed was immersed in an aqueous solution of HCl (2 mol / L) for 10 minutes to prepare a coupon.

The electromagnetic wave shielding film from which the upper first base film was removed was immersed in an aqueous solution of HCl (3%), H2SO4 (5%, NaOH (5%)) for 30 minutes to prepare a coupon. The evaluation of the chemical resistance of the insulating layer was carried out according to ASTM D 3359. The evaluation method and judgment criteria are shown in Fig.

4) Pencil Hardness

The hardness of the coating film was measured using the strength of graphite, which is the core of a pencil. First, the upper first base film was removed by producing a coupon by a lamination and pressing process in the same manner as the heat resistance evaluation coupon manufacturing method.

The pencil was shaved bluntly by the strength of the pencil, and the underside of the shim was smoothly rubbed with fine sandpaper. Thereafter, the upper first base film was pushed three times with a weight of 500 g so that the pencil lead reached the surface of the insulating layer of the electromagnetic wave shielding film from which the upper first base film was removed, and the insulating layer was peeled off or judged based on scratches.

5) Evaluation of electromagnetic wave shielding rate

Evaluation of Heat Resistance Characteristic The coupon was produced by the lamination and compression process in the same manner as the coupon manufacturing method, and the upper first base film was removed. The electromagnetic wave shielding film of the removed electromagnetic wave shielding film was prepared as shown in FIG. 5 and the electromagnetic wave shielding ratio for a frequency range of 30 MHz to 1 GHz was measured according to ASTM 4935-1. At this time, the tester used the Agilent 8719C Network Analyzer.

6) Contact resistance measurement

Two inner layer circuits were formed on the prepared cross-section FCCL with a width of 5 mm, a length of 50 mm and a spacing distance of 10 mm.

PI film 12.5 탆 and adhesive layer 15 탆 so that a square having a diameter of 0.15 mm and an area of 5 mm x 5 mm is positioned at the end of the inner layer circuit, Was subjected to a thermocompression bonding process at 150 DEG C for 60 minutes. The electroless gold plating was applied to the inner layer circuit which exposed copper by 0.15mm and 5mm × 5mm size by the coverlay punched out after the thermocompression process.

After the second base film of the prepared electromagnetic wave shielding film was removed, the electromagnetic wave shielding film was cut and layered in a width of 10 mm in the area of 0.15 mm located at the center of the inner layer circuit, and thermocompression process was performed at 150 캜 for 60 minutes at 35 kgf per unit area. The contact resistances of the two inner layer circuits exposed to a size of 5 mm were measured.

Second
the year before
Copper foil
(탆) Conductive adhesive layer thickness
(탆) Adhesion Heat resistance
(Solder) Chemical resistance
(Cross cut) pencil
Hardness Shielding rate
(dB) contact
resistance
(Ω) Comparative Example 1 0 4 to 5 ≥ 1.2 Pass 5B 1H 38 to 39 1.3 Example 1 One ≥ 1.2 Pass 5B 1H 83 0.1 Example 2 2 ≥ 1.2 Pass 5B 1H 84 0.1 Example 3 3 ≥ 1.2 Pass 5B 1H 88 0.1 Example 4 6 ≥ 1.2 Pass 5B 1H 99 0.1 Comparative Example 2 0 14-15 ≥ 1.2 Pass 5B 1H 45 to 46 0.3 Example 5 One ≥ 1.2 Pass 5B 1H 85 0.1 Example 6 2 ≥ 1.2 Pass 5B 1H 87 0.1 Example 7 3 ≥ 1.2 Pass 5B 1H 92 0.1 Example 8 6 ≥ 1.2 Pass 5B 1H 102 0.1

As a result of the experiment, it was confirmed that the electromagnetic wave shielding film according to the present invention not only exerts excellent electromagnetic shielding ratio, adhesive force, heat resistance and adhesive resistance, but also can simplify the manufacturing process by minimizing the multi- I could.

Claims (12)

(i) forming an insulating layer by coating a first surface of a first base film with a thermosetting resin composition for forming an insulating layer;
(ii) depositing a peelable double-layer copper foil comprising a second copper foil, a pressure-sensitive adhesive layer and a carrier first copper foil on the insulating layer, bonding the insulating layer and the second copper foil, step;
(iii) coating a resin composition for forming a conductive adhesive layer including a conductive filler and a thermosetting resin on a first side of a second base film, and then drying to form a conductive adhesive layer; And
(iv) depositing a first base film and a second base film, placing the second base film of the first base film and the conductive adhesive layer of the second base film in contact with each other,
Wherein the electromagnetic wave shielding film is made of a metal. The method according to claim 1,
Wherein the thickness of the second copper foil is in the range of 1 to 12 占 퐉 and the thickness of the first copper foil is larger than that of the second copper foil in the separable double-layer copper foil of step (ii). The method according to claim 1,
Wherein the second copper foil of step (ii) is attached on the first side of the insulating layer and is used as a metal layer of the electromagnetic wave shielding film. The method according to claim 1,
Wherein the thermosetting resin composition for forming an insulating layer in the step (i) comprises a thermally-decomposable resin and 0.5 to 5 parts by weight of an electrically non-conductive filler based on 100 parts by weight of the composition . The method according to claim 1,
Wherein the thickness of the insulating layer formed in step (i) is in the range of 5 to 20 占 퐉. The method according to claim 1,
Wherein the conductive filler of the resin composition for forming a conductive adhesive layer in step (iii) is a copper filler, a nickel filler, or a polymer filler coated with Ag, Cu, Ni, Al or Ag. The method according to claim 1,
Wherein the content of the conductive filler is in the range of 30 to 70 parts by weight based on 100 parts by weight of the composition. The method according to claim 1,
The insulating layer formed in the step (i) is semi-hardened (B-stage)
Wherein the conductive adhesive layer formed in step (iii) is semi-cured (B-stage). The method according to claim 1,
Wherein the first base film and the second base film are made of polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, a polyethylene film, a polypropylene film, a cellophane, a diacetylcellulose film, a triacetylcellulose film, Polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film (PET) selected from the group consisting of polyethylene terephthalate (PET), polyethylene terephthalate (PET), polyether sulfone film, polyetherimide film, polyimide film, fluorine resin film, polyamide film, acrylic resin film, norbornene resin film and cycloolefin resin film Characterized in that the electromagnetic wave absorber Method of producing a film. The method according to claim 1,
Wherein the first base film and the second base film are each a release-treated film. The method according to claim 1,
Wherein the first base film disposed on the insulating layer side is matted, corona-treated, or contains beads inside. The method according to claim 1,
Wherein the total thickness of the second copper foil and the conductive adhesive layer is in the range of 3 to 5 占 퐉 or in the range of 13 to 15 占 퐉.

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