KR20180027388A - Electromagnetic wave shield film - Google Patents

Abstract

The present invention is to realize an electromagnetic wave shield film of which discoloration due to wiping of a fingerprint is not easily generated. According to the present invention, the electromagnetic wave shield film has an insulation layer (110) and a conductive layer (120). Sa is 0.8 μm or more, wherein Sa is three-dimensional arithmetic mean surface roughness on a surface of the insulation layer (110).

Description

ELECTROMAGNETIC WAVE SHIELD FILM

The present invention relates to an electromagnetic wave shield film.

2. Description of the Related Art In smart phones and tablet type information terminals, performance of transferring a large amount of data at high speed is required in recent years. In order to transmit a large amount of data at a high speed, it is necessary to use a high-frequency signal. However, when a high frequency signal is used, electromagnetic noise is generated from the signal circuit provided on the printed wiring board, and the peripheral device is liable to malfunction. In order to prevent such a malfunction, it is important to shield the printed wiring board from electromagnetic waves.

In order to shield a printed wiring board, a method of obtaining a shield print wiring board by heating and pressing an electromagnetic shielding film having an insulating layer and a shield layer on a printed wiring board (see, for example, Patent Document 1).

On the surface of the insulating layer of the electromagnetic wave shielding film, a protective film formed of polyethylene terephthalate (PET) resin or the like is bonded to protect the insulating layer from scratches or foreign matter. The protective film is peeled after the electromagnetic wave shielding film is bonded to the printed wiring board. Until the protective film is peeled off, the surface of the insulating layer is protected, and the shield printed wiring board can be handled with bare hands.

Japanese Patent Application Laid-Open No. 2004-095566

However, if the shield printed wiring board after peeling off the protective film is handled with bare hands, there is a possibility that the fingerprint is attached to the insulating layer from which the protective film has been removed. The place where the fingerprint is attached is discolored and the appearance is damaged, so that there is a problem that the yield is lowered.

Even if the fingerprint is attached to the insulating layer, there is almost no influence on the characteristics of shielding the electromagnetic wave. Therefore, discoloration of the insulating layer due to the attached fingerprint can be suppressed, and the yield of the shield printed wiring board can be suppressed from decreasing. As a method for suppressing the discoloration of the insulating layer by the attached fingerprint, it may be considered to remove the fingerprint. Detergents and solvents are generally used to remove fingerprints. However, in the case of the insulating layer of the electromagnetic wave shielding film, there is a fear that the electrical characteristics of the shielded printed circuit board may be affected, and a detergent or a solvent can not be used.

Further, in the case of the conventional electromagnetic wave shielding film, when the surface is rubbed with a nonwoven fabric or the like to wipe the fingerprint, the surface state is locally changed, and the degree of discoloration becomes rather large. Further, if a large force is applied and the surface is rubbed, the insulating layer may peel off from the shielding layer, and the electromagnetic wave shielding film may be damaged.

An object of the present invention is to realize an electromagnetic wave shielding film which does not easily cause discoloration due to wiping of a fingerprint.

The first aspect of the electromagnetic shielding film of the present invention includes an insulating layer and a conductive layer, and the insulating layer has a three-dimensional arithmetic average surface roughness Sa of 0.8 mu m or more.

In the first aspect of the electromagnetic wave shielding film, the insulating layer can have an 85 占 degree glossiness at the surface of 20 or less.

The second aspect of the electromagnetic shielding film of the present invention comprises an insulating layer and a conductive layer, and the insulating layer has a root mean square slope Sdq of 0.8 or more and a polished degree of 85 deg.

The third aspect of the electromagnetic shielding film of the present invention comprises an insulating layer and a conductive layer, and the insulating layer has a skewness Ssk at the surface of 0.1 or more and an 85 占 glossiness of 10 or less.

In each aspect of the electromagnetic wave shielding film, the insulating layer may have an L * value of 25 or less.

According to the electromagnetic shielding film of the present invention, discoloration due to wiping of the fingerprint can be prevented easily.

1 is a cross-sectional view showing an electromagnetic wave shielding film according to one embodiment.
2 is a cross-sectional view showing an electromagnetic wave shielding film according to a modification.
3 is a plot showing the relationship between the root mean square slope and the gloss of the insulating layer.
4 is a plot showing the relationship between the skewness and the gloss of the insulating layer.

Hereinafter, the electromagnetic shielding film of the present invention will be specifically described. However, the present invention is not limited to the following embodiments, and can be suitably modified and applied within the scope of the present invention.

(Electromagnetic wave shielding film)

1 is a schematic cross-sectional view schematically showing an electromagnetic wave shielding film of the present embodiment. As shown in Fig. 1, the electromagnetic wave shielding film has an insulating layer 110 and a shielding layer 120 which is a conductive layer. On the surface of the shielding layer 120 opposite to the insulating layer 110, an adhesive layer 130 may be provided if necessary. By providing the adhesive layer 130, the electromagnetic wave shielding film can be easily bonded to the printed wiring board.

- Insulation layer -

The insulating layer 110 is provided to protect the shielding layer. In the electromagnetic shielding film of the present embodiment, the insulating layer 110 has a three-dimensional arithmetic mean surface roughness Sa of 0.8 mu m or more, preferably 1.0 mu m or more, which is a parameter showing the surface property. When Sa is 0.8 탆 or more, the insulating layer having a surface with little discoloration due to wiping of the fingerprint can be formed. In this case, a surface on which a fingerprint is wiped off by virtue of the wiping of the fingerprint means that a portion to which the fingerprint is attached is wiped with a wiping cloth or the like, Surface.

From the viewpoint of the actual removability of the fingerprint component, Sa is preferably 10 m or less, more preferably 5 m or less, and further preferably 3 m or less. The smaller the Sa is, the easier the peeling of the insulating layer from the release film to be described later can be obtained. Further, if Sa exceeds the above-mentioned value, it becomes difficult to wipe the attached fingerprint.

The degree of discoloration due to the wiping of the fingerprint can be evaluated qualitatively by sensory evaluation in which the surface of the insulating layer 110 after the fingerprint is wiped is visually observed. Further, it can be evaluated quantitatively according to the change in gloss of the surface. As a method of quantitatively evaluating, a method of measuring the degree of gloss of 85 degrees on the surface of the insulating layer 110 after the fingerprint is attached and polished can be used. In this case, it is difficult to visually identify the trace of wiping the fingerprint when the degree of 85 ° gloss after the fingerprint is attached and polished is preferably 20 or less, more preferably 10 or less. As another quantitative evaluation method, a method of measuring the difference between the gloss of the surface of the insulating layer 110 after the fingerprint is attached and polished and the glossiness before the fingerprint is attached may be used. That is, the smaller the difference between the glossiness on the surface of the insulating layer 110 after the fingerprint is attached and polished and the glossiness before the fingerprint is applied, the smaller the degree of discoloration due to the fingerprint wiping. For example, in the case of an 85 degree gloss, when the difference in gloss between the fingerprints attached and polished and the degree of gloss before adhering the fingerprints is preferably 4 or less, more preferably 3 or less, It is difficult to distinguish between the fingerprint portion and the portion where the fingerprint is wiped.

In the electromagnetic shielding film of the present embodiment, the parameters of the surface property other than Sa on the surface of the insulating layer 110 can be as follows from the viewpoint of not easily causing discoloration due to wiping off of the fingerprint. The root-mean-square slope Sdq is preferably 0.8 or more, and more preferably 0.95 or more. The portion to which the fingerprint is attached is easier to reflect light than the portion where the fingerprint is not attached, so that the portion where the fingerprint is attached becomes conspicuous. Further, as the color tone of the surface of the insulating layer 110 is black and the L * value is smaller, the fingerprint attaching portion tends to be conspicuous. On the other hand, if Sdq is large enough, the light can be made into a surface that is easily scattered to an appropriate degree, and the increase of reflection due to the attachment of the fingerprint can be suppressed. In particular, when the L * value is 25 or less, it is effective to make Sdq large so that the fingerprint attaching portion is not conspicuous.

From the viewpoint of easy peeling of the insulating layer from the release film described later, Sdq is preferably 10 or less, more preferably 7.0 or less, still more preferably 3.0 or less.

The skewness Ssk is preferably 0.1 or more, more preferably 0.5 or more, and further preferably 1.0 or more. Ssk represents the symmetry of the convex portion and the concave portion with reference to the average surface in the concavo-convex surface, and the larger the Ssk is, the less the component of the convex portion with respect to the average surface becomes, and the portion (the valley portion) And the flat portion) are relatively increased. Therefore, the fingerprint can be easily wiped out by increasing Ssk to some extent.

The Ssk is preferably 10 or less, more preferably 5.0 or less, and further preferably 3.0 or less. By setting Ssk to such a range, an effect of easily peeling off the insulating layer from the release film described later can be expected.

In addition, the maximum peak height Sp is preferably 8.0 m or more. The square-root mean square deviation Sq is preferably 1.0 占 퐉 or more, more preferably 1.2 占 퐉 or more, and further preferably 1.3 占 퐉 or more. The projecting peak height Spk is preferably 1.0 占 퐉 or more, more preferably 1.5 占 퐉 or more, and further preferably 1.7 占 퐉 or more. The void volume Vvc of the core portion is preferably 1.1 ml / m ² or more, and more preferably 1.3 ml / m ² or more. The volumetric volume Vmp of the mountain part is preferably 0.07 ml / m ² or more, more preferably 0.08 ml / m ² or more, and still more preferably 0.1 ml / m ² or more.

Further, it is preferable that Sp is 20 탆 or less, more preferably 18 탆 or less, even more preferably 15 탆 or less. Sq is preferably 10 m or less, more preferably 5.0 m or less, and further preferably 3.0 m or less. The Spk is preferably 10 탆 or less, more preferably 5.0 탆 or less, and further preferably 3.0 탆 or less. The Vvc is preferably 10 ml / m ² or less, more preferably 5.0 ml / m ² or less, and further preferably 3.0 ml / m ² or less. The Vmp is preferably 1.0 ml / m ² or less, more preferably 0.5 ml / m ² or less, and further preferably 0.3 ml / m ² or less. Sp, Spk, Vvc and Vmp are in the above-described numerical ranges, respectively, and an effect of easily peeling off the insulating layer from the release film to be described later can be expected.

It is also possible to define a surface which does not easily cause discoloration due to wiping of the fingerprint by other parameters without being defined by Sa. For example, in order to make the surface which does not easily cause discoloration due to the wiping of the fingerprint, a surface having a small proportion of convex portions based on the average surface and a high convex portion is considered to be preferable. Therefore, Sp may be 7.0 탆 or more, preferably 8.0 탆 or more, and Ssk may be 0 or more, and preferably 0.1 or more. Further, Sp may be 7.0 탆 or more, preferably 8.0 탆 or more, and Sdq may be 0.8 or more, and preferably 0.9 or more. Further, Sq may be 1.0 占 퐉 or more and Ssk may be 0 or more, and preferably 0.1 or more. Also, Sq may be 1.0 탆 or more, preferably 1.2 탆 or more, and Sdq may be 0.8 or more, and preferably 0.9 or more. Further, the Spk may be 1.0 탆 or more and the Ssk may be 0 or more, and preferably 0.1 or more. Further, the Spk may be 1.0 탆 or more, preferably 1.5 탆 or more, and Sdq may be 0.8 or more, and preferably 0.9 or more.

Further, Sp may be 20 탆 or less, preferably 18 탆 or less, and Ssk may be 10 or less, preferably 5 or less. Further, Sp may be 20 탆 or less, preferably 18 탆 or less, and Sdq may be 10 or less, preferably 3.0 or less. Further, Sq is 10 mu m or less, preferably 5 mu m or less, and Ssk is 10 or less, preferably 5.0 or less. Further, Sq may be 10 탆 or less, preferably 5.0 탆 or less, and Sdq may be 10 or less, preferably 3.0 or less. Further, the Spk is 10 탆 or less, preferably 5.0 탆 or less, and the Ssk is 10 or less, preferably 5.0 or less. Further, the Spk is 10 탆 or less, preferably 5.0 탆 or less, and Sdq is 10 or less, preferably 3.0 or less. With such a range, an effect of easily peeling the insulating layer from the peeling film can be expected.

The surface property in the present invention is a value measured based on ISO 25178-6: 2010, and a specific measuring method will be described in the embodiment.

The degree of gloss of the insulating layer 110 before the fingerprint is attached is preferably 3 or less, more preferably 2 or less, and still more preferably 1 or less. Further, the degree of gloss of 85 ° is preferably 20 or less, more preferably 15 or less, further preferably 10 or less, still more preferably 5 or less, and still more preferably 3 or less.

When the glossiness before the fingerprint is attached is set to such a value, scattering of light to a suitable degree occurs on the surface of the insulating layer 110, and the glossiness is suppressed to an appropriate degree. Thus, discoloration due to wiping of the fingerprint can be prevented more easily.

Particularly, the 60 degree glossiness before the fingerprint of the insulating layer 110 is adhered is preferably 3 or less, more preferably 2 or less, further preferably 1 or less, and the 85 degree glossiness is preferably 20 or less , More preferably not more than 15, even more preferably not more than 10, still more preferably not more than 5, and even more preferably not more than 3, to a surface which is hardly discolored due to wiping of the fingerprint can do.

The 60 占 glossiness and 85 占 glossiness in the present disclosure can be measured by the method shown in Examples.

Particularly, when Sdq is not less than 0.8, preferably not less than 0.9, and 85 占 glossiness is not more than 10, preferably not more than 5, and more preferably not more than 3, discoloration due to wiping of the fingerprint can be easily prevented have.

Further, by setting Ssk to be greater than 0, preferably not less than 0.1, more preferably not less than 0.5, and an 85 ° glossiness of not more than 10, preferably not more than 5, more preferably not more than 3, It is possible to prevent the discoloration caused by the light emitting layer from easily occurring.

In this disclosure, the method of obtaining the insulating layer 110 is not particularly limited, and a known method can be used. For example, the resin composition for forming the insulating layer 110 is coated on the surface of the release film provided with the concavo-convex shape by embossing and dried, thereby transferring the concavoconvex shape of the release film to the insulation layer 110, Can be used. A method may be employed in which a resin composition containing unevenness-forming particles is applied to the surface of the shielding layer 120 and then dried to form the insulating layer 110 having a concavo-convex shape. A method of spraying dry ice or the like on the surface of the insulating layer 110 can be used. A method of applying the active energy ray-curable composition to the surface of the shielding layer 120 and then pressing the mold having the concave-convex shape to cure the curable composition layer and peeling the mold may be used. Other known methods may be used.

Among these methods, from the viewpoint of productivity, a method of applying the resin composition containing the unevenness-forming particles and drying the resin composition to obtain the insulating layer 110 having the concavo-convex shape is preferable. In this case, the unevenness-forming particles are not particularly limited, and for example, resin fine particles or inorganic fine particles can be used. The resin fine particles may be acrylic resin fine particles, polyacrylonitrile fine particles, polyurethane fine particles, polyamide fine particles, and polyimide fine particles. The inorganic fine particles may be fine particles of calcium carbonate, calcium silicate fine particles, clay, kaolin, talc, silica fine particles, glass fine particles, diatomaceous earth, mica powder, alumina fine particles, magnesium oxide fine particles, zinc oxide fine particles, Calcium sulfate fine particles, and magnesium carbonate fine particles. These resin fine particles and inorganic fine particles may be used alone or in combination of two or more. From the viewpoint of enhancing the anti-friction property of the insulating layer, inorganic fine particles are preferable.

The unevenness-forming particles preferably have a 50% average particle size of 2 탆 or more, more preferably 4 탆 or more, and more preferably 10 탆 or less, from the viewpoint of obtaining proper surface irregularities on the surface of the insulating layer 110, Mu m or more. Further, in order to suppress whitening of the insulating layer, it is preferable that the 50% average particle diameter is 30 占 퐉 or less, more preferably 20 占 퐉 or less.

The amount of the unevenness-forming particles added to the insulating layer 110 is preferably 3% by mass or more, more preferably 5% by mass or more from the viewpoint of obtaining a predetermined surface property. From the viewpoint of suppressing the whitening of the insulating layer, it is preferably 30 mass% or less, more preferably 20 mass% or less, and further preferably 17 mass% or less.

In the insulating layer 110, a black coloring agent may be added. By adding the black coloring agent, the L * value of the insulating layer 110 can be made small, and the visibility of the marking (characters, figures, etc.) printed on the surface of the insulating layer can be improved. When the marking for printing on the insulating layer 110 is white, the L * value is preferably 25 or less, more preferably 20 or less, and even more preferably 18 or less. The L * value in the present disclosure can be measured in accordance with JIS Z 8781-4 (2013).

The black colorant may be a black pigment or a mixed pigment obtained by blackening a plurality of pigments by mixing them with each other. The black pigment may be any one of, for example, carbon black, ketjen black, carbon nanotube (CNT), perylene black, titanium black, iron black, and aniline black, or a combination thereof. The mixed pigments can be used by mixing pigments such as red, green, blue, yellow, purple, cyan and magenta.

The particle diameter of the black colorant is not limited so long as it can realize the required L * value. However, from the viewpoints of reduction in dispersibility and L * value, the average primary particle diameter is preferably 20 nm or more, more preferably 100 nm or less . The average primary particle diameter of the black colorant can be obtained from an average value of about 20 primary particles that can be observed from an image enlarged by about 50,000 to 100,000 times by a transmission electron microscope (TEM).

From the viewpoint of decreasing the L * value, the addition amount of the black coloring agent to the insulating layer 110 is preferably 0.5% by mass or more, and more preferably 1% by mass or more. However, the black coloring agent may be added as needed, and it may not be added.

In addition, the glossiness affects the visibility of the factors. From the viewpoint of the visibility of the print, the 60 ° gloss of the insulating layer 110 is preferably 3 or less, more preferably 2 or less, further preferably 1 or less. The 85 占 glossiness is preferably 20 or less, more preferably 15 or less, further preferably 10 or less, still more preferably 5 or less, and still more preferably 3 or less.

The insulating layer 110 preferably has necessary insulating properties and satisfies predetermined mechanical strength, chemical resistance, and heat resistance.

The resin material constituting the insulating layer is not particularly limited as long as it has sufficient insulating properties. For example, a thermoplastic resin composition, a thermosetting resin composition, and an active energy ray curable composition can be used.

The thermoplastic resin composition is not particularly limited, but a styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin composition, a polypropylene resin composition, an imide resin composition, and an acrylic resin composition may be used . The thermosetting resin composition is not particularly limited, but a phenol resin composition, an epoxy resin composition, a urethane resin composition, a melamine resin composition, and an alkyd resin composition can be used. The active energy ray curable composition is not particularly limited, and for example, a polymerizable compound having two or more (meth) acryloyloxy groups in the molecule can be used. These compositions may be used alone, or two or more of them may be used in combination.

In addition to the above-mentioned fine particles and the colorant, the insulating layer 110 may contain a curing accelerator, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, a defoamer, A leveling agent, a filler, a flame retardant, a viscosity adjusting agent, and an anti-blocking agent.

The thickness of the insulating layer 110 is not particularly limited and may be appropriately set as necessary. However, from the viewpoint of sufficiently protecting the shielding layer, the thickness is preferably 1 占 퐉 or more, more preferably 4 占 퐉 or more. Further, from the viewpoint of ensuring the flexibility of the electromagnetic wave shielding film, it is preferably 20 占 퐉 or less, more preferably 10 占 퐉 or less.

- Shielding layer -

The shielding layer 120 of the present embodiment may be a metal layer. The shielding layer 120 may be a metal layer made of any one of nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium and zinc, or an alloy containing two or more of them. The material and thickness of the metal layer may be suitably selected in accordance with the required electromagnetic wave shielding effect and repeated flexing and sliding resistance. From the viewpoint of obtaining a sufficient electromagnetic wave shielding effect, the thickness of the metal layer is preferably 0.1 mu m or more. Further, from the viewpoints of productivity and flexibility, it is preferable that the thickness is 8 占 퐉 or less. The metal layer can be formed by an electrolytic plating method, an electroless plating method, a sputtering method, an electron beam evaporation method, a vacuum evaporation method, a CVD method, a metal organic or the like. The metal layer may be formed of a metal foil, metal nanoparticles, scaly metal particles, or the like.

- Adhesive layer -

The electromagnetic shielding film of the present embodiment may be provided with the adhesive layer 130 on the side opposite to the insulating layer 110 of the shielding layer 120. [ The adhesive layer 130 can be formed of an adhesive resin composition. The adhesive resin composition is not particularly limited, and examples thereof include a styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin composition, a polypropylene resin composition, an imide resin composition, an amide resin composition, A thermosetting resin composition such as a phenol resin composition, an epoxy resin composition, a urethane resin composition, a melamine resin composition and an alkyd resin composition can be used. These may be used alone, or two or more of them may be used in combination.

The adhesive layer 130 may be a layer having isotropic (conductive) or anisotropic conductivity as required. When the adhesive layer 130 is made of a layer having isotropic or anisotropic conductivity, conductive fine particles may be added to the adhesive resin composition.

The conductive fine particles are not particularly limited, but fine metal particles, carbon nanotubes, carbon fibers, metal fibers and the like can be used. For example, metal fine particles such as silver powder, copper powder, nickel powder, solder powder, and aluminum powder can be used. It is also possible to use silver coated copper foil subjected to plating and metal coated fine particles coated with metal fine particles, glass beads or the like. Above all, from the viewpoint of economical efficiency, a copper powder or a silver coating copper which can be obtained at low cost is preferable.

The 50% average particle diameter of the conductive particles is not particularly limited, but is preferably 0.5 m or more from the viewpoint of obtaining good conductivity. Further, from the viewpoint of thinning the conductive adhesive layer, it is preferable that the thickness is 15 mu m or less.

The shape of the conductive particles is not particularly limited, and can be appropriately selected from a spherical shape, a flat shape, a scaly shape, a dendrite shape, and the like.

The thickness of the adhesive layer 130 can be adjusted as needed, but is preferably 0.5 占 퐉 or more from the viewpoint of obtaining good adhesion. Further, from the viewpoint of thinning the electromagnetic shielding film, it is preferable that the thickness is 20 mu m or less.

The electromagnetic shielding film has the insulating layer 110 and the shielding layer 120 and the adhesive layer 130. The insulating layer 110 and the isotropic conductive adhesive layer 140 as shown in FIG.

The insulating layer 110 may have the same structure as the electromagnetic shielding film shown in Fig. The isotropically conductive adhesive layer 140 can be formed of the same adhesive resin composition and conductive fine particles as the adhesive layer 130. The isotropic conductive adhesive layer 140 functions as a shielding layer.

- Method for producing shielding film -

The electromagnetic wave shielding film of the present embodiment can be produced by a known manufacturing method. An example is shown below.

First, a conductive adhesive layer 130 is formed on a support film having a surface subjected to releasing treatment. Specifically, a solution of an adhesive layer composition containing a material constituting the adhesive layer 130 is coated on the surface of the support film and dried to form the adhesive layer 130. [

Next, a shielding layer 120 is formed on the surface of the adhesive layer 130. Specifically, a method of bonding a metal foil previously formed to a predetermined thickness to the adhesive layer 130, or a method of forming a metal layer on the surface of the adhesive layer 130 by vapor deposition or plating or the like can be used.

Next, an insulating layer 110 is formed on the surface of the shielding layer 120. Specifically, a method of applying a solution of an insulating layer composition containing a material constituting the insulating layer 110 to the surface of the shielding layer 120 and drying may be used.

Thereafter, the support film is peeled off to obtain an electromagnetic wave shielding film.

The insulating layer 110 may be formed on the surface of the isotropic conductive adhesive layer 140 by using the adhesive layer 130 as the isotropic conductive adhesive layer 140.

The surface of the insulating layer 110 may be subjected to a treatment such as sandblasting in order to set the surface property of the surface of the insulating layer 110 to a predetermined state.

Is formed from the side of the adhesive layer 130. However, it may be formed sequentially from the side of the insulating layer 110. [ In this case, the surface property of the insulating layer 110 may be set to a predetermined state by transferring a fine pattern to the surface of the insulating layer 110 using a support film having a fine pattern.

[Example]

Hereinafter, the present invention will be described in detail by way of examples. The following examples are illustrative, and the present invention is not particularly limited.

<Fabrication of electromagnetic wave shielding film>

- Preparation of adhesive layer -

, 100 parts by mass of a bisphenol A type epoxy resin (jER1256, manufactured by Mitsubishi Chemical Corporation), 0.1 part by mass of a curing agent (ST14 manufactured by Mitsubishi Chemical Corporation), and 0.1 part by mass of a silane- (Average particle diameter: 13 mu m) were added and stirred to prepare a conductive adhesive layer composition. The resulting adhesive layer composition was applied to a PET film whose surface had been subjected to release treatment and then heated and dried to form an adhesive layer on the surface of the support film.

- Fabrication of shielding layer -

A rolled copper foil (copper foil) having a thickness of 2 占 퐉 was bonded to the surface of the obtained adhesive layer.

- Fabrication of insulation layer -

100 parts by mass of a bisphenol A type epoxy resin (jER1256, manufactured by Mitsubishi Chemical Corporation), 0.1 part by mass of a curing agent (ST14 manufactured by Mitsubishi Chemical Corporation) and 0.1 part by mass of carbon as a black colorant were added to toluene so that the solid content was 20 mass% 15 parts by mass of particles (Toka Black # 8300 / F, manufactured by Tokai Carbon Co., Ltd.) and predetermined amounts of unevenness-forming particles were blended to prepare an insulating layer composition. This composition was applied to the obtained shielding layer and dried by heating to obtain an electromagnetic wave shielding film.

&Lt; Property evaluation method &

[Measurement of surface property of insulating layer]

5 arbitrary portions of the surface of the insulating layer of the electromagnetic wave shielding film were measured using a confocal microscope (OPTELICS HYBRID manufactured by Lasertec Co., Ltd., objective lens 20 times), and then data was analyzed using data analysis software (LMeye7) And the surface properties were measured according to ISO 25178-6: 2010, and the arithmetic average thereof was obtained. The cutoff wavelength of the S filter was 0.0025 mm, and the cutoff wavelength of the L filter was 0.8 mm.

[Measurement of L * value]

The L * value was measured using an integral spherical spectrometer (X-Rite, Ci64, tungsten light source). The a * value and the b * value were also measured.

[Evaluation of discoloration due to fingerprint]

The surface of a rubber stopper having a diameter of 2.5 cm was damaged with # 240 abrasive paper. Subsequently, 5 占 퐇 of artificial saliva (JIS C9606: manufactured by ISKEI) was dropped onto the surface of the PET film, and the damaged surface of the rubber stopper was pressed against the artificial mouth (500g load, 10 seconds). Then, a rubber stopper with an artificial mouthpiece was pressed against the surface of the insulating layer (500 g load for 10 seconds) to adhere the artificial mouthpiece. Subsequently, the nonwoven fabric (Wippher X70, manufactured by Japan Paper Cressia Co., Ltd.) was cut into a size of about 3 cm x 3 cm, placed on the artificial remover, and reciprocated 20 times at a load of 500 g (one-way distance = 10 cm). The value obtained by subtracting the value of the 85 ° glossiness before the attachment of the artificial mouthpiece from the value of 85 ° gloss after wiping was taken as an 85 ° gloss difference. 60 ° gloss and 85 ° gloss were measured using a BYK Gardner micro-gloss (portable gloss meter).

(Example 1)

As the unevenness-forming particles to be applied to the insulating layer, silica particles having an average particle size of 7 mu m were used and the blending amount was 40 parts by mass. The surface of the insulating layer of the obtained electromagnetic wave shielding film had a Sa of 1.02 占 퐉, an Sdq of 1.26 and a Ssk of 2.22. The 60 degree glossiness before the artificial mouth attachment was 1.1, and the 60 degree glossiness after the fingerprint was wiped was 5.2. The 85 degree glossiness before the artificial fixation was 1.5, the 85 degree glossiness after wiping off the fingerprints was 1.9, and the 85 degree glossiness difference was 0.4. The L * value was 21.3.

(Example 2)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1 except that the blending amount of the unevenness-forming particles was changed to 50 parts by mass. The surface of the insulating layer of the obtained electromagnetic wave shielding film had Sa of 1.18 占 퐉, Sdq of 1.26 and Ssk of 2.21. The 60 degree glossiness before attachment of the artificial mouth was 0.5, and the 60 degree glossiness after wiping off the fingerprints was 6.7. The 85 degree glossiness before the artificial fixation was 1.8, the 85 degree glossiness after wiping off the fingerprints was 2.4, and the 85 degree glossiness difference was 0.6. The L * value was 20.1.

(Example 3)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1 except that the blending amount of the unevenness-forming particles was changed to 35 parts by mass. The surface of the insulating layer of the obtained electromagnetic wave shielding film had Sa of 1.31 占 퐉, Sdq of 0.95, and Ssk of 1.47. The 60 degree glossiness before attachment of artificial mouth was 0.5, and the 60 degree glossiness after wiping fingerprints was 1.8. The 85 degree glossiness before the artificial fixation was 1.7, the 85 degree glossiness after wiping the fingerprints was 2.5, and the 85 degree glossiness difference was 0.8. The L * value was 20.1.

(Example 4)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1, except that silica particles having an average particle size of 9 占 퐉 were used as the unevenness-forming particles, and the blending amount was changed to 40 parts by mass. The surface SA of the obtained electromagnetic wave shielding film was 0.92 占 퐉, Sdq was 1.38, and Ssk was 3.10. The 60 degree glossiness before adhesion with artificial remedy was 2.1, and the 60 degree glossiness after wiping fingerprints was 6.1. The 85 degree glossiness before the artificial fixation was 2.1, the 85 degree glossiness after wiping the fingerprints was 2.6, and the 85 degree glossiness difference was 0.5. The L * value was 23.5.

(Example 5)

An electromagnetic wave shielding film was obtained in the same manner as in Example 4 except that the blending amount of the unevenness-forming particles was changed to 50 parts by mass. The surface of the insulating layer of the obtained electromagnetic wave shielding film had a Sa of 0.92 占 퐉, an Sdq of 1.02 and a Ssk of 2.53. The 60 degree glossiness before attachment of the artificial mouth was 1.5, and the 60 degree glossiness after wiping off the fingerprints was 4.9. The polish degree at 85 ° before the artificial fixation was 1.7, the polish degree at 85 ° was 3.2, and the polish degree at 85 ° was 1.5 after the fingerprints were wiped off. The L * value was 24.3.

(Example 6)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1, except that silica particles having an average particle diameter of 5 탆 were used as the unevenness-forming particles, and the blending amount was changed to 70 parts by mass. The surface of the insulating layer of the obtained electromagnetic wave shielding film had a thickness Sa of 1.05 μm, an Sdq value of 0.92, and an Ssk value of 0.80. The 60 degree glossiness before attaching the artificial mouth was 0.5, and the 60 degree glossiness after wiping the fingerprints was 2.4. The polish degree at 85 ° before adhesion with artificial mouth was 4.6, the polish degree at 85 ° was 6.3, and the polish degree at 85 ° was 1.7 after wiping off the fingerprints. The L * value was 23.6.

(Example 7)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1 except that silica particles having an average particle diameter of 7 탆 were used as the unevenness-forming particles, and the blending amount was changed to 60 parts by mass. The surface SA of the obtained electromagnetic wave shielding film was 1.11 mu m, Sdq was 1.12, and Ssk was 1.46. The 60 degree glossiness before attachment of the artificial mouth was 0.4, and the 60 degree glossiness after wiping off the fingerprints was 1.9. The 85 degree glossiness before the artificial fixation was 3.8, the 85 degree glossiness after wiping the fingerprints was 6.5, and the 85 degree glossiness difference was 2.7. The L * value was 21.9.

(Comparative Example 1)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1 except that silica particles having an average particle diameter of 2 탆 were used as the unevenness-forming particles, and the blending amount was changed to 60 parts by mass. On the surface of the insulating layer of the obtained electromagnetic wave shielding film, Sa was 0.57 占 퐉, Sdq was 0.80, and Ssk was 0.07. The 60 degree glossiness before attaching the artificial mouth was 0.8, and the 60 degree glossiness after wiping the fingerprints was 2.2. The polish degree at 85 ° before the artificial fixation was 16.8, the polish degree at 85 ° was 26.7 and the polish degree at 85 ° was 9.9 after the fingerprints were wiped off. The L * value was 24.4.

(Comparative Example 2)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 1 except that the blending amount of the unevenness-forming particles was changed to 65 parts by mass. Sa, Sdq, and Ssk of the surface of the insulating layer of the obtained electromagnetic wave shielding film were 0.66 占 퐉, 0.90, and -0.22, respectively. The 60 degree glossiness before attachment of the artificial mouth was 0.5, and the 60 degree glossiness after wiping off the fingerprints was 3.9. The 85 degree glossiness before the artificial mouth attachment was 15.9, the 85 degree glossiness after wiping the fingerprints was 30.4, and the 85 degree glossiness difference was 14.5. The L * value was 21.9.

(Comparative Example 3)

An insulating layer composition containing no particles for forming irregularities was prepared. This was coated on the surface of the support film and dried and cured to obtain an insulating layer. The support film was a releasably treated PET film having a thickness of 20 mu m provided with a concavo-convex shape (Sa = 0.60 mu m, Sdq = 0.61) on the surface by embossing. Next, after the insulating layer was bonded to the shielding layer prepared in the same manner as in Example 1, the support film was peeled off to obtain an electromagnetic wave shielding film. The surface of the insulating layer of the obtained electromagnetic wave shielding film had a S a of 0.58 μm, an S dq of 0.65, and an Ssk of -0.78. The 60 degree glossiness before attachment of the artificial mouth was 4.2, and the 60 degree glossiness after wiping fingerprints was 9.1. The 85 degree glossiness before the artificial fixation was 34.0, the 85 degree glossiness after polishing the fingerprints was 42.8, and the 85 degree glossiness difference was 8.8. The L * value was 25.3.

(Comparative Example 4)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that silica fine particles were blended as a support film to give a concavo-convex shape (Sa = 0.6 mu m, Sdq = 0.47 mu m) on the surface. The surface of the insulating layer of the obtained electromagnetic wave shielding film had a thickness of 0.59 mu m, an Sdq of 0.49, and an Ssk of -0.85. The 60 degree glossiness before adhesion with artificial mouth was 7.6, and the 60 degree glossiness after wiping fingerprints was 13.3. The 85 ° glossiness before attachment to the artificial mouth was 38.7, the 85 ° gloss after polishing the fingerprint was 48.0, and the 85 ° gloss difference was 9.3. The L * value was 28.2.

(Comparative Example 5)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that the support film was provided with a concavo-convex shape (Sa = 0.47 mu m, Sdq = 0.59 mu m) on the surface by sand mat processing. Sa, Sdq, and Ssk of the surface of the insulating layer of the obtained electromagnetic wave shielding film were 0.45 占 퐉, 0.58 and -0.25, respectively. The degree of 60 ° gloss before adhesion with artificial mouth was 5.4, and the degree of 60 ° gloss after cleansing fingerprints was 11.9. The 85 ° glossiness before the artificial fixation was 26.1, the 85 ° glossiness after polishing the fingerprints was 51.0, and the 85 ° glossiness difference was 24.9. The L * value was 27.2.

(Comparative Example 6)

As the support film, an electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3, except that the surface was provided with a concavo-convex shape (Sa = 0.45 mu m, Sdq = 0.56 mu m) by sand matting. The surface of the insulating layer of the obtained electromagnetic wave shielding film had a Sa of 0.45 mu m, an Sdq of 0.54, and an Ssk of -0.60. The 60 degree glossiness before attachment of the artificial mouth was 9.2, and the 60 degree glossiness after wiping fingerprints was 16.6. The 85 degree glossiness before attachment of the artificial mouth was 30.4, the 85 degree glossiness after polishing the fingerprints was 54.7, and the 85 degree glossiness difference was 24.3. The L * value was 27.2.

(Comparative Example 7)

As the support film, an electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that the surface was provided with a concavo-convex shape (Sa = 0.51 mu m, Sdq = 0.55 mu m) by sand matting. The surface Sa of the obtained electromagnetic wave shielding film had an insulating layer surface of 0.49 mu m, Sdq of 0.55, and Ssk of -0.37. The degree of 60 ° gloss before adhesion with artificial mouth was 8.6, and the degree of 60 ° gloss after polishing fingerprints was 16.7. The polish degree at 85 ° before adhesion with the artificial fix was 21.6, the polish degree at 85 ° was 56.7 and the polish degree at 85 ° was 35.1 after the fingerprints were wiped off. The L * value was 27.2.

(Comparative Example 8)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that silica fine particles were blended as a support film to give a concavo-convex shape (Sa = 0.43 mu m, Sdq = 0.40 mu m) on the surface. Sa, Sdq and Ssk of the surface of the insulating layer of the obtained electromagnetic wave shielding film were 0.42 mu m, 0.38 mu m and -1.19, respectively. The 60 ° glossiness before adhesion with the artificial mouth was 11.7, and the 60 ° gloss after polishing the fingerprints was 17.9. The 85 ° glossiness before the artificial fixation was 52.4, the 85 ° glossiness after polishing the fingerprints was 58.9, and the 85 ° glossiness difference was 6.5. The L * value was 27.9.

(Comparative Example 9)

An electromagnetic wave shielding film was obtained in the same manner as in Example 1 except that silica particles having an average particle diameter of 5 탆 were used as particles to be applied to the insulating layer and the blending amount was changed to 40 parts by mass. Sa, Sdq, and Ssk of the surface of the insulating layer of the obtained electromagnetic wave shielding film were 0.49 占 퐉, 0.74, and -0.77, respectively. The 60 degree glossiness before adhesion with artificial mouth was 1.0, and the 60 degree glossiness after wiping fingerprints was 19.8. The 85 degree glossiness before attachment of the artificial mouth was 33.2, the 85 degree glossiness after polishing the fingerprints was 61.0, and the 85 degree glossiness difference was 27.8. The L * value was 22.0.

(Comparative Example 10)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that silica fine particles were blended as a support film to give a concavo-convex shape (Sa = 0.36 mu m, Sdq = 0.36 mu m) on the surface. Sa, Sdq, and Ssk of the surface of the insulating layer of the obtained electromagnetic wave shielding film were 0.35 占 퐉, 0.36 and -0.31, respectively. The 60 degree glossiness before adhesion with artificial remedy was 6.9, and the 60 degree glossiness after wiping fingerprints was 12.1. The 85 degree glossiness before attachment of the artificial mouth was 58.6, the 85 degree glossiness after polishing the fingerprints was 63.0, and the 85 degree glossiness difference was 4.4. The L * value was 26.3.

(Comparative Example 11)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that silica fine particles were blended as a support film to give a concavo-convex shape (Sa = 0.46 mu m, Sdq = 0.65 mu m) on the surface. Sa, Sdq, and Ssk of the surface of the insulating layer of the obtained electromagnetic wave shielding film were 0.43 占 퐉, 0.62, and -0.40, respectively. The 60 degree glossiness before attachment to the artificial mouth was 2.4, and the 60 degree glossiness after wiping fingerprints was 16.6. The 85 degree glossiness before adhesion with artificial mouth was 42.6, the 85 degree glossiness after wiping off the fingerprints was 71.8, and the 85 degree glossiness difference was 29.2. The L * value was 28.2.

(Comparative Example 12)

An electromagnetic wave shielding film was obtained in the same manner as in Comparative Example 3 except that silica fine particles were blended as a support film to give a concavo-convex shape (Sa = 0.31 mu m, Sdq = 0.58 mu m) on the surface. The surface of the insulating layer of the obtained electromagnetic wave shielding film had Sa of 0.34 mu m, Sdq of 0.55, and Ssk of -0.48. The 60 degree glossiness before adhesion with artificial mouth was 4.3, and the 60 degree glossiness after wiping fingerprints was 30.2. The 85 degree glossiness before the artificial mouth attachment was 64.2, the 85 degree glossiness after wiping off the fingerprints was 80.6, and the 85 degree glossiness difference was 16.4. The L * value was 24.4.

(Comparative Example 13)

An insulating layer was applied to the surface of the support film in the same manner as in Comparative Example 3 except that a PET film having a concavo-convex shape (Sa = 1.5 占 퐉, Sdq = 4.89 占 퐉) was imparted to the surface by embossing as a support film, Cured. Next, the insulating layer was bonded to the shielding layer produced in the same manner as in Example 1. [ Subsequently, although the support film was intended to be peeled off, the support film and the insulating layer strongly adhered to each other, and interfacial destruction of the insulating layer / shielding layer occurred in a part thereof. On the surface of the insulating layer where interface failure was not observed, Sa was 1.3 mu m, Sdq was 3.6, and Ssk was -1.60. In this Comparative Example, since the interface failure occurred, the gloss and the L * value were not measured.

Table 1 shows the surface properties and the discoloration of the electromagnetic wave shielding films of the respective Examples and Comparative Examples. Table 1 also shows values of Sp, Sq, Spk, Vvc, Vmp, a * and b *.

[Table 1]

Fig. 3 shows the relationship between Sdq and 85 占 glossiness. When the Sdq is at least 0.8 and the 85 degree gloss is 10 or less, the gloss difference becomes 4 or less, and discoloration due to wiping of the fingerprint is not easily caused.

Fig. 4 shows the relationship between Ssk and the 85 占 glossiness. When the Ssk is at least 0.1 and the 85 degree gloss is 10 or less, the gloss difference becomes 4 or less, and discoloration due to wiping of the fingerprint is not easily caused.

INDUSTRIAL APPLICABILITY The electromagnetic shielding film of the present invention can prevent easily discoloration due to wiping of a fingerprint, and is useful as an electromagnetic wave shielding film for use in printed wiring boards and the like.

110: insulating layer
120: shielding layer
130: adhesive layer
140: isotropic conductive adhesive layer

Claims (5)

An insulating layer and a shield layer,
Wherein the insulating layer has a three-dimensional arithmetic mean surface roughness Sa on the surface of not less than 0.8 mu m. The method according to claim 1,
Wherein the insulating layer has an 85 占 degree gloss on the surface of 20 or less. An insulating layer and a shielding layer,
Wherein the insulating layer has a square mean square root slope Sdq at the surface of 0.8 or more and an 85 占 glossiness of 10 or less. An insulating layer and a shielding layer,
Wherein the insulating layer has a skewness Ssk at the surface of 0.1 or more and an 85 ° gloss of 10 or less. 5. The method according to any one of claims 1 to 4,
Wherein the insulating layer has an L * value of 25 or less.

Images