Anti-electromagnetic interference film and preparation method thereof

Abstract

An electromagnetic interference (EMI) resistant film includes a flexible composite metal layer, a transparent insulating layer, and a conductive adhesive layer. The conductive adhesive layer is formed by removing a solvent from a conductive adhesive component, which includes an acrylate solution, a divalent acid ester solution, multiple conductive particles, and a solvent. The present invention further includes a method for manufacturing the EMI resistant film.

Description

Technical Field

[0001] The present invention relates to an anti-electromagnetic interference film and a manufacturing method thereof, and in particular to an anti-electromagnetic interference film and a manufacturing method thereof that can take into account both adhesion strength and electrical reliability. Background Art

[0002] With the development of electronic products and the trend of miniaturization of electronic products, flexible printed circuit boards are becoming more and more important. Especially for office machines, communication machines and mobile electronic products, the electromagnetic interference problems that need to be dealt with by multifunctionality, high performance and miniaturization are more important. Therefore, electromagnetic wave shielding films are generally designed on many flexible printed circuit boards to shield electromagnetic noise. However, since the electromagnetic wave shielding films in the prior art must be able to be attached to irregular surfaces composed of various types of mechanisms or components, the metal content in the electromagnetic wave shielding films must be limited. However, such limitations will affect the electromagnetic wave shielding ability and thermal conductivity of the electromagnetic wave shielding film, and it is impossible to take into account the adhesion strength, heat resistance and electrical reliability at the same time.

[0003] Therefore, how to design an anti-electromagnetic interference film and a method for manufacturing the same, especially to solve the aforementioned technical problems of the prior art, is an important topic studied by the inventors of this case. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an anti-electromagnetic interference film, which can solve the problem that the electromagnetic wave shielding ability and thermal conductivity of the prior art cannot be improved, and achieve the purpose of taking into account the adhesion strength, heat resistance and electrical reliability at the same time.

[0005] In order to achieve the above-mentioned object, the present invention provides an anti-electromagnetic interference film including a flexible composite metal layer, a transparent insulating layer and a conductive adhesive layer. Wherein, the flexible composite metal layer includes at least two stacked metal layers. The transparent insulating layer is disposed on one side of the flexible composite metal layer. The conductive adhesive layer is disposed on the other side of the flexible composite metal layer, and the conductive adhesive layer is formed by removing the solvent from a conductive adhesive composition, and the conductive adhesive composition includes 30 to 40 parts by weight of an acrylate solution, 30 to 40 parts by weight of a divalent acid ester solution, 2 to 5 parts by weight of a plurality of conductive particles and a solvent. When the acrylate solution is 100 parts by weight, the acrylate solution includes 30 to 40 parts by weight of acrylate. 50% of the plurality of conductive particles have a particle size of 5 microns to 10 microns.

[0006] Furthermore, the acrylate includes one of methacrylate resin, methyl methacrylate resin, ethyl acrylate resin, ethyl methyl acrylate resin, propyl acrylate resin, propyl methyl acrylate resin, butyl acrylate resin and butyl methyl acrylate resin, and combinations thereof.

[0007] Furthermore, each conductive particle includes one of carbon particles, silver particles, copper particles, nickel particles, solder, and silver-coated copper particles, and combinations thereof.

[0008] Further, the solvent includes one of toluene, ethyl acetate, methyl ethyl ketone oxime, xylene, acetone, methyl ethyl ketone / methyl ethyl ketone, isopropyl alcohol, butyl acetate, and propylene glycol methyl ether acetate, and combinations thereof.

[0009] Furthermore, the conductive adhesive composition further includes 0.01 to 1 parts by weight of a nano-conductive additive, wherein the nano-conductive additive includes one of nano-carbon tubes, nano-silver, organic conductive coatings, and graphene, and a combination thereof.

[0010] Furthermore, the conductive adhesive composition further includes 1 to 5 parts by weight of additives, wherein the additives include one or a combination of a polymerization accelerator, a dispersant, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, a defoaming agent, a leveling agent, a filler, a flame retardant, a silicone coupling agent, an antioxidant, an antistatic agent, and a viscosity modifier.

[0011] Another object of the present invention is to provide a method for manufacturing an anti-electromagnetic interference film, which can solve the problem that the electromagnetic wave shielding ability and thermal conductivity of the prior art cannot be improved, thereby achieving the purpose of taking into account adhesion strength, heat resistance and electrical reliability at the same time.

[0012] In order to achieve the aforementioned other purpose, the method for making the anti-electromagnetic interference film proposed in the present invention includes: stacking at least two metal layers into a flexible composite metal layer. Disposing a transparent insulating layer on one side of the flexible composite metal layer. Disposing a conductive adhesive layer on the other side of the flexible composite metal layer. Wherein, the conductive adhesive layer is formed by removing the solvent from a conductive adhesive composition, and the conductive adhesive composition includes 30 to 40 parts by weight of an acrylate solution, 30 to 40 parts by weight of a divalent acid ester solution, 2 to 5 parts by weight of a plurality of conductive particles and a solvent. Wherein, when the acrylate solution is 100 parts by weight, the acrylate solution includes 30 to 40 parts by weight of acrylate. 50% of the plurality of conductive particles have a particle size of 5 microns to 10 microns.

[0013] Furthermore, the method for preparing the anti-electromagnetic interference film further includes: placing the conductive adhesive composition at room temperature and stirring the conductive adhesive composition at a rotation speed of 60 rpm for eight hours, then adding ethyl acetate or toluene after the conductive adhesive composition is allowed to stand for 60 minutes to control the viscosity of the conductive adhesive composition to 10 cps to 50 cps.

[0014] Furthermore, during the stirring of the conductive adhesive composition, energy is output to the conductive adhesive composition to improve the uniformity of the conductive adhesive composition.

[0015] Furthermore, the process of configuring a conductive adhesive layer on a flexible composite metal layer includes: placing a conductive adhesive composition at room temperature, and applying the conductive adhesive composition to the flexible composite metal layer, and then heating the conductive adhesive composition in an environment of 140 degrees Celsius to 150 degrees Celsius for 4 minutes to 5 minutes to remove the solvent from the conductive adhesive composition and form a conductive adhesive layer with a thickness of 3 microns to 5 microns.

[0016] Furthermore, the acrylate includes one of methacrylate resin, methyl methacrylate resin, ethyl acrylate resin, ethyl methyl acrylate resin, propyl acrylate resin, propyl methyl acrylate resin, butyl acrylate resin and butyl methyl acrylate resin, and combinations thereof.

[0017] Furthermore, each conductive particle includes one of carbon particles, silver particles, copper particles, nickel particles, solder, and silver-coated copper particles, and combinations thereof.

[0018] Further, the solvent includes one of toluene, ethyl acetate, methyl ethyl ketone oxime, xylene, acetone, methyl ethyl ketone / methyl ethyl ketone, isopropyl alcohol, butyl acetate, and propylene glycol methyl ether acetate, and combinations thereof.

[0019] Furthermore, the conductive adhesive composition further includes 0.01 to 1 parts by weight of a nano-conductive additive, wherein the nano-conductive additive includes one of nano-carbon tubes, nano-silver, organic conductive coatings, and graphene, and a combination thereof.

[0020] Furthermore, the conductive adhesive composition further includes 1 to 5 parts by weight of additives, wherein the additives include one or a combination of a polymerization accelerator, a dispersant, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, a defoaming agent, a leveling agent, a filler, a flame retardant, a silicone coupling agent, an antioxidant, an antistatic agent, and a viscosity modifier.

[0021] The beneficial effect of the present invention is that when the anti-electromagnetic interference film of the present invention is used, the flexible composite metal layer can be adhered to any surface of the electronic component through the conductive adhesive layer. Since the conductive adhesive layer is formed by removing the solvent from the conductive adhesive composition, and the acrylate solution included in the conductive adhesive composition can have both flexible bending resistance and heat resistance, especially for the application of flexible printed circuit boards, the conductive adhesive layer must have the effects of bending resistance, break resistance and component heating resistance, and can be applied to mechanical structures that need to be bent repeatedly, and the conductive adhesive layer of the present invention has an adhesion of more than 4N / cm, without worrying about the adhesion strength problem. In addition, since 50% of the number of multiple conductive particles has a particle size of 5 microns to 10 microns, the flatness and adhesion strength of the adhesion surface can be maintained, and since the multiple conductive particles only occupy 2 to 5 parts by weight in the conductive adhesive composition, the adhesion of the acrylate will not be significantly changed, and the conductive particles can also enable the conductive adhesive layer to have a shielding ability of 55dB against 1GHz electromagnetic interference.

[0022] To this end, the anti-electromagnetic interference film and the manufacturing method thereof described in the present invention can solve the problem that the electromagnetic wave shielding ability and thermal conductivity of the prior art cannot be improved, and achieve the purpose of taking into account the adhesion strength, heat resistance and electrical reliability at the same time.

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, but is not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the anti-electromagnetic interference film of the present invention;

[0025] Figure 2 is a schematic diagram of the drying steps of the anti-electromagnetic interference film of the present invention; and

[0026] Figure 3 and Figure 4 It is a schematic flow chart of the method for preparing the anti-electromagnetic interference film of the present invention.

[0027] Wherein, the reference numerals are:

[0028] 10: Flexible composite metal layer

[0029] 11: Soft silver metal layer

[0030] 12: Soft copper metal layer

[0031] 20: Transparent insulation layer

[0032] 30: Conductive adhesive layer

[0033] 40: First release film

[0034] 50: Second release film

[0035] 100: Heating unit

[0036] S1~S3: Steps

[0037] S31~S35: Steps DETAILED DESCRIPTION

[0038] The following describes the implementation of the present invention by means of specific embodiments, and those familiar with the art can easily understand other advantages and effects of the present invention from the contents provided in this specification. The present invention can also be implemented or applied by means of other different specific examples, and the details in the present invention specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0039] It should be noted that the structures, proportions, sizes, number of components, etc. shown in the drawings of this specification are only used to match the contents provided in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented, so they have no substantive technical significance. Any modification of the structure, change in the proportion relationship or adjustment of the size should fall within the scope of the technical content provided by the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0040] The structural principle and working principle of the present invention are described in detail below in conjunction with the accompanying drawings:

[0041] See also Figure 1 and Figure 2 As shown. Among them, Figure 1 It is a schematic structural diagram of the anti-electromagnetic interference film of the present invention. Figure 2 It is a schematic diagram of the drying steps of the anti-electromagnetic interference film of the present invention.

[0042] The anti-electromagnetic interference film proposed in the present invention includes a flexible composite metal layer 10, a transparent insulating layer 20 and a conductive adhesive layer 30. The flexible composite metal layer 10 includes at least two stacked metal layers. In an embodiment of the present invention, the flexible composite metal layer 10 may be formed by stacking a soft silver metal layer 11 and a soft copper metal layer 12, but the present invention is not limited thereto.

[0043] The transparent insulating layer 20 is disposed on one side of the flexible composite metal layer 10. In the embodiment of the present invention, the transparent insulating layer 20 is first disposed on one side of the flexible composite metal layer 10, and then the conductive adhesive layer 30 is disposed on the other side of the flexible composite metal layer 10, but the present invention is not limited thereto.

[0044] The conductive adhesive layer 30 is disposed on the other side of the flexible composite metal layer 10. The conductive adhesive layer 30 is formed by removing a solvent (not shown) from a conductive adhesive composition (not shown). The conductive adhesive composition may include 30 to 40 parts by weight of an acrylate solution, 30 to 40 parts by weight of a divalent acid ester solution, 2 to 5 parts by weight of a plurality of conductive particles, and a solvent. When the acrylate solution is 100 parts by weight, the acrylate solution may include 30 to 40 parts by weight of acrylate. That is, in addition to the solvent, the acrylate solution may include 30wt% to 40wt% of acrylate. 50% of the plurality of conductive particles have a particle size of 5 microns (μm) to 10 microns. The conductive adhesive layer 30 can electrically connect the flexible composite metal layer 10 to the flexible circuit board or the components of the circuit board to which the conductive adhesive layer 30 is adhered (for example, the ground wire of the connecting component).

[0045] Furthermore, the resin composition that can be used to make the conductive adhesive layer 30 can be thermoplastic resin (polystyrene, vinyl acetate, polyester, polyethylene, polypropylene, polyamide, rubber, acrylic, etc.) or thermosetting resin (phenol, epoxy, urethane, melamine, alkyd, etc.). Among them, acrylic has both bending resistance and heat resistance, and is particularly reliable for use in flexible printed circuit boards that require repeated bending.

[0046] The acrylate described in the embodiments of the present invention refers to a resin containing an acrylate compound or an acrylate polymer, and acrylate is an ester derived from acrylic acid. Acrylic acid is generally an unsaturated carboxylic acid containing a vinyl group and a carboxyl group. The acrylate used in the present invention includes one of methacrylate resin, methyl methacrylate resin, ethyl acrylate resin, ethyl methyl acrylate resin, propyl acrylate resin, propyl methyl acrylate resin, butyl acrylate resin and butyl methyl acrylate resin and a combination thereof. In some embodiments of the present invention, the acrylate can use methacrylate resin or methyl methacrylate resin.

[0047] As mentioned above, the solvent in the acrylate solution or the solvent of the conductive adhesive composition may include toluene, ethyl acetate (EAC), methyl ethyl ketone oxime (MEKO), xylene, acetone, methyl ethyl ketone / methyl ethyl ketone (MEK), isopropyl alcohol (IPA), butyl acetate (BAC) and propylene glycol methyl ether acetate (PMA) and a combination thereof. In an embodiment of the present invention, the solvent in the acrylate solution may be ethyl acetate (EAC), and the solvent of the conductive adhesive composition may be toluene, but the present invention is not limited thereto. The solvent of the conductive adhesive composition may be adjusted so that the total weight parts are close to 100 weight parts. Alternatively, the solvent of the conductive adhesive composition may be increased or decreased as needed so that the conductive adhesive composition has a suitable viscosity when being coated.

[0048] Further, each conductive particle may include one of carbon particles, silver particles, copper particles, nickel particles, solder and silver-coated copper particles and a combination thereof. The silver-coated copper particles are prepared by silver plating copper powder. In an embodiment of the present invention, the conductive particles may use nickel particles, and at least 50% of the conductive particles have a particle size of 5 microns to 10 microns. In an embodiment of the present invention, the conductive adhesive composition further includes 0.01 to 1 parts by weight of nano-conductive additives and 1 to 5 parts by weight of additives. Among them, the nano-conductive additive may include a semiconductor filament with a length of less than 10 microns, such as one of carbon nanotubes, nanosilver, organic conductive coatings and graphene and a combination thereof. The organic conductive coating may be: poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS)). The additives may include one or a combination of polymerization accelerator, dispersant (such as silicone coupling agent), tackifier, antioxidant, pigment, dye, plasticizer, ultraviolet absorber, defoamer, leveling agent, filler, flame retardant, silicone coupling agent, antioxidant, antistatic agent and viscosity modifier. The polymerization accelerator may be used to control the adhesion time of the conductive adhesive layer 30 and improve the adhesion effect of the conductive adhesive layer 30.

[0049] In addition, in the actual manufactured product, the outer side of the transparent insulating layer 20 is covered with a first release film 40 to protect the transparent insulating layer 20 . The outer side of the conductive adhesive layer 30 is covered with a second release film 50 to protect the conductive adhesive layer 30 .

[0050] As mentioned above, the conductive adhesive layer 30 is formed by removing the solvent from the conductive adhesive composition. Figure 2 As shown, the conductive adhesive composition applied to the flexible composite metal layer 10 can be heated by the heating unit 100, so that the conductive adhesive composition is heated in an environment of 140 degrees Celsius to 150 degrees Celsius for 4 minutes to 5 minutes to remove the solvent from the conductive adhesive composition and form a conductive adhesive layer 30 with a thickness of 3 microns to 5 microns.

[0051] See also Figure 3 and Figure 4 FIG. 1 is a flow chart of the method for making the anti-electromagnetic interference film of the present invention. Figure 1 shown.

[0052] The method for manufacturing the anti-electromagnetic interference film of the present invention comprises: laminating at least two metal layers into a flexible composite metal layer 10 (step S1). Disposing a transparent insulating layer 20 on one side of the flexible composite metal layer 10 (step S2). Disposing a conductive adhesive layer 30 on the other side of the flexible composite metal layer 10 (step S3).

[0053] In an embodiment of the present invention, the method for making an anti-electromagnetic interference film further includes: preparing a conductive adhesive composition (step S31), wherein the conductive adhesive composition may include: 30 to 40 parts by weight of an acrylate solution, 30 to 40 parts by weight of a divalent acid ester solution, 2 to 5 parts by weight of a plurality of conductive particles, 0.01 to 1 parts by weight of a nano conductive additive, 1 to 5 parts by weight of an additive and a solvent added in sequence. When the acrylate solution is 100 parts by weight, the acrylate solution includes 30 to 40 parts by weight of acrylate. 50% of the plurality of conductive particles have a particle size of 5 microns to 10 microns.

[0054] Next, the conductive adhesive composition is placed at room temperature (e.g., 25 degrees Celsius), and the conductive adhesive composition can be stirred at a speed of 60 rpm by a stirrer (not shown) for eight hours (step S32), and then the conductive adhesive composition is allowed to stand for 60 minutes and ethyl acetate (EAC) or toluene is added to control the viscosity of the conductive adhesive composition to 10cps to 50cps (step S33). During the stirring of the conductive adhesive composition, energy can be output to the conductive adhesive composition by an energy output unit (not shown) to improve the uniformity of the conductive adhesive composition. The energy output unit may include thermal energy (such as a water bath, an oil bath, an electric heater, a heat exchange tube), radiation energy (such as ultraviolet light irradiation, gamma ray irradiation) or a combination of the foregoing, to increase the energy of the conductive adhesive composition during the reaction, so as to increase its temperature, so as to improve the uniformity of heat transfer and reaction. For example, the conductive adhesive composition can be heated and stirred at the same time.

[0055] Finally, the conductive adhesive composition is placed at room temperature (e.g., 25 degrees Celsius) and coated (e.g., by Die Coater mold coating) on ​​the flexible composite metal layer 10 (step S34), and then the conductive adhesive composition is heated in an environment of 140 degrees Celsius to 150 degrees Celsius for 4 minutes to 5 minutes to remove the solvent from the conductive adhesive composition and form a conductive adhesive layer 30 with a thickness of 3 microns to 5 microns (step S35).

[0056] When the anti-electromagnetic interference film of the present invention is used, the flexible composite metal layer 10 can be adhered to any surface of the electronic component through the conductive adhesive layer 30. Since the conductive adhesive layer 30 is formed by removing the solvent from the conductive adhesive composition, and the acrylate solution included in the conductive adhesive composition can have both flexible bending resistance and heat resistance, especially for the application of flexible printed circuit boards, the conductive adhesive layer 30 must have the effects of bending resistance, break resistance and component heating resistance, and can be used on mechanical structures that need to be bent repeatedly. The conductive adhesive layer 30 of the present invention has an adhesion of more than 4N / cm, and there is no need to worry about the adhesion strength problem. In addition, since 50% of the number of multiple conductive particles has a particle size of 5 microns to 10 microns, the flatness and adhesion strength of the adhesion surface can be maintained, and since the multiple conductive particles only occupy 2 to 5 parts by weight of the conductive adhesive composition, the adhesion of the acrylate will not be significantly changed, and the conductive particles can also enable the conductive adhesive layer 30 to have a shielding ability of 55dB against 1GHz electromagnetic interference.

[0057] To this end, the anti-electromagnetic interference film and the manufacturing method thereof described in the present invention can solve the problem that the electromagnetic wave shielding ability and thermal conductivity of the prior art cannot be improved, and achieve the purpose of taking into account the adhesion strength, heat resistance and electrical reliability at the same time.

[0058] The following may be multiple embodiments of the present invention:

[0059] <Example 1>

[0060] First, prepare an acrylate solution, with 12.5 grams of polyalkyl acrylate compound and 22.5 grams of ethyl acetate (EAC), stir evenly at room temperature using a 300 ml three-necked glass reactor, stir evenly for two hours with a two-impeller stirrer, then add 35.0 grams of dibasic acid ester solution, 25 grams of solvent (toluene), 3 grams of nickel particle powder (more than 50% of the particle size is 5-10um), 2 parts by weight of dispersant, 0.5 grams of PEDOT:PSS with a concentration of 1-2.5%, continue stirring at room temperature for eight hours, let stand for one hour, and then add EAC or toluene as needed to adjust the viscosity, so as to control the viscosity of the conductive adhesive composition to 30cps-50cps. The ingredients are shown in Table 1. After production, the resin composition is coated on the flexible composite metal layer by a Die Coater mold coating method at room temperature. After coating, the surface is dried by heating. The heating conditions can heat the conductive adhesive composition in an environment of 140 degrees Celsius to 150 degrees Celsius for 4 minutes to 5 minutes to remove the solvent from the conductive adhesive composition and form a conductive adhesive layer 30 with a thickness of 3 microns to 5 microns.

[0061] <Example 2>

[0062] Resin composition 2 was prepared in the same manner as in Example 1, except that the amount of the polyalkyl acrylate compound in the acrylate solution was adjusted to 10 g and the weight of EAC was adjusted to 25 g, as shown in Table 1.

[0063] <Example 3>

[0064] Resin composition 3 was prepared in the same manner as in Example 1, except that the amount of the polyalkyl acrylate compound in the acrylate solution was adjusted to 14 g and the weight of EAC was adjusted to 21 g, as shown in Table 1.

[0065] <Example 4>

[0066] Resin composition 4 was prepared in the same manner as in Example 1, except that the amount of the acrylic acid ester solution was adjusted to 30 g and the weight of the dibasic acid ester solution was adjusted to 40 g, as shown in Table 1.

[0067] <Example 5>

[0068] Resin composition 5 was prepared in the same manner as in Example 1, except that the amount of the acrylic acid ester solution was adjusted to 40 g and the weight of the dibasic acid ester solution was adjusted to 30 g, as shown in Table 1.

[0069] <Example 6>

[0070] Resin composition 6 was prepared in the same manner as in Example 1, except that PEDOT:PSS was replaced with 0.05 g of carbon nanotubes, as shown in Table 1.

[0071] <Comparative Example 1>

[0072] A control resin composition 1' was prepared in the same manner as in Example 1, except that the amount of the polyalkyl acrylate compound in the acrylate solution was adjusted to 7 g and the weight of EAC was adjusted to 28 g, as shown in Table 1.

[0073] <Comparative Example 2>

[0074] A control resin composition 2' was prepared in the same manner as in Example 1, except that the amount of the polyalkyl acrylate compound in the acrylate solution was adjusted to 17.5 g and the weight of EAC was adjusted to 17.5 g, as shown in Table 1.

[0075] <Comparative Example 3>

[0076] A control resin composition 3' was prepared in the same manner as in Example 1, except that the amount of the acrylic acid ester solution was adjusted to 20 g and the weight of the dibasic acid ester solution was adjusted to 50 g, as shown in Table 1.

[0077] <Comparative Example 4>

[0078] A control resin composition 4' was prepared in the same manner as in Example 1, except that the amount of the acrylic acid ester solution was adjusted to 50 g and the weight of the dibasic acid ester solution was adjusted to 20 g, as shown in Table 1.

[0079] <Comparative Example 5>

[0080] A control resin composition 5' was prepared in the same manner as Example 1, except that the original nickel particles were replaced with 80% by number of nickel particles having a particle size of 1 to 4 microns, as shown in Table 1.

[0081] <Comparative Example 6>

[0082] A control resin composition 6' was prepared in the same manner as in Example 1, except that no PEDOT:PSS or carbon nanotubes were added, as shown in Table 1.

[0083] [Table 1]

[0084]

[0085] Note: Supplementary instructions for finished product inspection items:

[0086] [Peeling test]

[0087] The adhesive layer of the EMI shielding film is laminated with PP or copper foil, and then the EMI shielding film and the object are peeled off and the tensile force (unit: N / cm) of the adhesive layer is measured with a tensile tester.

[0088] [Surface Residue Analysis]

[0089] After the EMI shielding film is laminated to the copper foil, the film is exposed to 85°C and 85% humidity for 24 hours. The EMI shielding film is peeled off and examined with an optical microscope. Five points per unit area of ​​10 cm are randomly selected within the A4 size of the copper foil. 2 The residual glue condition inside.

[0090] As shown in Table 1 above, Examples 1 to 5 of the present invention have excellent film-forming properties, heat resistance and adhesion that can reach 4N / cm or more. The appearance of the actual finished product can also be kept flat without bubbles or unevenness, the hygroscopicity can still be maintained below 0.5%, and the amount of residual glue on the surface of the attached object is low. Among them, adding necessary conductive additives, such as PEDOT:PSS or nanocarbon tubes, to the composition of Examples 1 to 6 of the present invention can make the anti-electromagnetic interference film of the present invention have a shielding ability of 55dB against 1GHz electromagnetic interference (EMI).

[0091] In addition, the control resin compositions 1 and 3 listed in Table 1 have poor film-forming properties, insufficient heat resistance, poor surface molding, and insufficient adhesion of the finished products with lower content of polyalkyl acrylate. The control resin compositions 2 and 4 have higher content of polyalkyl acrylate, and the actual finished products have uneven film-forming surfaces and serious surface residual glue. In addition, because the film is thicker than 5 microns, the conductive nickel particles have fewer contact points with the grounding wire when attached to the copper foil, so the electromagnetic interference shielding capability of 1GHz can only reach 40dB. The control resin composition 5 further verifies that if a smaller particle composition is used, such as 80% of the nickel particles have a particle size of 1 micron to 4 microns, the electromagnetic interference shielding capability of 1GHz can only reach 30dB. The control resin composition 6 shows that if no auxiliary conductive additives such as PEDOT:PSS or carbon nanotubes are added to the solvent composition, the electromagnetic interference shielding capability of 1GHz can only reach 50dB.

[0092] The anti-electromagnetic interference film of the present invention is tested in an environment of 85 degrees Celsius and 85% humidity, and can still maintain a low resistance value so that the shielding function is not invalidated. The composite metal layer adopts a double-layer structure to effectively improve the conductivity and the reliability of electromagnetic interference shielding.

[0093] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. An anti-electromagnetic interference film, characterized in that: include: A flexible composite metal layer comprising at least two stacked metal layers; a transparent insulating layer, disposed on one side of the flexible composite metal layer; as well as a conductive adhesive layer disposed on the other side of the flexible composite metal layer, the conductive adhesive layer being formed by removing a solvent from a conductive adhesive composition, the conductive adhesive composition comprising 30 to 40 parts by weight of an acrylate solution, 30 to 40 parts by weight of a divalent acid ester solution, 2 to 5 parts by weight of a plurality of conductive particles, and the solvent; Wherein, when the acrylate solution is 100 parts by weight, the acrylate solution includes 30 parts by weight to 40 parts by weight of an acrylate; 50% of the plurality of conductive particles have a particle size of 5 micrometers to 10 micrometers, The outer side of the conductive adhesive layer is covered with a release film to protect the conductive adhesive layer.

2. The anti-electromagnetic interference film according to claim 1, characterized in that: The acrylic ester includes one of methacrylate resin, methyl methacrylate resin, ethyl acrylate resin, ethyl methyl acrylate resin, propyl acrylate resin, propyl methyl acrylate resin, butyl acrylate resin and butyl methyl acrylate resin, and combinations thereof.

3. The anti-electromagnetic interference film according to claim 1, characterized in that: Each of the conductive particles includes one of carbon particles, silver particles, copper particles, nickel particles, solder, and silver-coated copper particles, and combinations thereof.

4. The anti-electromagnetic interference film according to claim 1, characterized in that: The solvent includes one of toluene, ethyl acetate, methyl ethyl ketone oxime, xylene, acetone, methyl ethyl ketone / methyl ethyl ketone, isopropyl alcohol, butyl acetate and propylene glycol methyl ether acetate, and a combination thereof.

5. The anti-electromagnetic interference film according to claim 1, characterized in that: The conductive adhesive composition further includes 0.01 to 1 parts by weight of a nano conductive additive, wherein the nano conductive additive includes one of nano carbon tubes, nano silver, organic conductive coatings and graphene, and a combination thereof.

6. The anti-electromagnetic interference film according to claim 1, characterized in that: The conductive adhesive composition further includes 1 to 5 parts by weight of an additive, which includes one or a combination of a polymerization accelerator, a dispersant, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, a defoamer, a leveling agent, a filler, a flame retardant, a silicone coupling agent, an antistatic agent, and a viscosity modifier.

7. A method for preparing an anti-electromagnetic interference film, characterized in that: include: laminating at least two metal layers into a flexible composite metal layer; Disposing a transparent insulating layer on one side of the flexible composite metal layer; as well as Disposing a conductive adhesive layer on the other side of the flexible composite metal layer; The conductive adhesive layer is formed by removing a solvent from a conductive adhesive composition, wherein the conductive adhesive composition includes 30 to 40 parts by weight of an acrylic acid ester solution, 30 to 40 parts by weight of a divalent acid ester solution, 2 to 5 parts by weight of a plurality of conductive particles, and the solvent; Wherein, when the acrylate solution is 100 parts by weight, the acrylate solution includes 30 parts by weight to 40 parts by weight of an acrylate; 50% of the plurality of conductive particles have a particle size of 5 micrometers to 10 micrometers, The outer side of the conductive adhesive layer is covered with a release film to protect the conductive adhesive layer.

8. The method for producing the anti-electromagnetic interference film according to claim 7, characterized in that: Also includes: The conductive adhesive composition is placed at room temperature and stirred at a rotation speed of 60 rpm for eight hours. Then, the conductive adhesive composition is allowed to stand for 60 minutes and then ethyl acetate or toluene is added to control the viscosity of the conductive adhesive composition to be between 10 cps and 50 cps.

9. The method for producing an anti-electromagnetic interference film according to claim 8, characterized in that: During the stirring of the conductive adhesive composition, energy is output to the conductive adhesive composition to improve the uniformity of the conductive adhesive composition.

10. The method for manufacturing the anti-electromagnetic interference film according to claim 7, characterized in that: The process of disposing the conductive adhesive layer on the flexible composite metal layer comprises: The conductive adhesive composition is placed at room temperature and coated on the flexible composite metal layer, and then the conductive adhesive composition is heated in an environment of 140 degrees Celsius to 150 degrees Celsius for 4 minutes to 5 minutes to remove the solvent from the conductive adhesive composition and form a conductive adhesive layer with a thickness of 3 microns to 5 microns.

11. The method for manufacturing the anti-electromagnetic interference film according to claim 7, characterized in that: The acrylic ester includes one of methacrylate resin, methyl methacrylate resin, ethyl acrylate resin, ethyl methyl acrylate resin, propyl acrylate resin, propyl methyl acrylate resin, butyl acrylate resin and butyl methyl acrylate resin, and combinations thereof.

12. The method for manufacturing the anti-electromagnetic interference film according to claim 7, characterized in that: Each of the conductive particles includes one of carbon particles, silver particles, copper particles, nickel particles, solder, and silver-coated copper particles, and combinations thereof.

13. The method for manufacturing the anti-electromagnetic interference film according to claim 7, characterized in that: The solvent includes one of toluene, ethyl acetate, methyl ethyl ketone oxime, xylene, acetone, methyl ethyl ketone / methyl ethyl ketone, isopropyl alcohol, butyl acetate and propylene glycol methyl ether acetate, and a combination thereof.

14. The method for manufacturing the anti-electromagnetic interference film according to claim 7, characterized in that: The conductive adhesive composition further includes 0.01 to 1 parts by weight of a nano conductive additive, wherein the nano conductive additive includes one of nano carbon tubes, nano silver, organic conductive coatings and graphene, and a combination thereof.

15. The method for manufacturing the anti-electromagnetic interference film according to claim 7, characterized in that: The conductive adhesive composition further includes 1 to 5 parts by weight of an additive, which includes one or a combination of a polymerization accelerator, a dispersant, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, a defoamer, a leveling agent, a filler, a flame retardant, a silicone coupling agent, an antistatic agent, and a viscosity modifier.

Images