Cover tape and electronic component packaging

Abstract

This cover tape has at least a base material layer and a heat seal layer, wherein the heat seal layer contains a polystyrene-based resin (A) and an ethylene-(meth)acrylic acid copolymer (B), and the content of component (A) and the content of component (B) are, respectively, greater than 80 parts by mass but less than or equal to 95 parts by mass, and greater than or equal to 5 parts by mass but less than 20 parts by mass, with respect to a total of 100 parts by mass of component (A) and component (B).

Description

Technical Field

[0001] The present invention relates to a cover tape and an electronic component package.

Background Art

[0002] With the miniaturization of electronic devices, the electronic components used are also becoming smaller and more highly functional. In the assembly process of electronic devices, components are automatically mounted on printed circuit boards. For the conveyance of such surface-mount electronic components, an electronic component package in which electronic components are accommodated in a carrier tape having pockets continuously thermally formed in accordance with the shape of the electronic components so that the electronic components can be continuously supplied is used.

[0003] An electronic component package is manufactured by accommodating electronic components in the pockets of a carrier tape, then overlaying a cover tape having a heat-sealing layer as a lid material on the upper surface of the carrier tape, and continuously heat-sealing both ends of the cover tape in the length direction with a heated seal bar (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, various electronic components such as capacitors, resistors, ICs, LEDs, connectors, and switching elements have been significantly miniaturized, lightened, and thinned, and the number of components mounted on a substrate has also increased. Therefore, from the perspective of improving the productivity of electronic component packages, the demand for high-speed sealing of cover tapes has been increasing. Also, from the perspective of energy conservation, reduction of the energy required for heat sealing is demanded.

[0006] One possible way to address these requirements is to lower the softening temperature of the heat-seal layer of the cover tape. However, in that case, as the softening temperature of the heat-seal layer decreases, the tapes tend to stick together more easily, and blocking is more likely to occur.

[0007] This invention has been made in view of the above circumstances, and aims to provide a cover tape that can be heat-sealed with less thermal energy while suppressing the occurrence of blocking, and an electronic component packaging using the same. [Means for solving the problem]

[0008] To solve the above problems, one aspect of the present invention provides a cover tape comprising at least a base layer and a heat seal layer, wherein the heat seal layer contains a polystyrene resin (A) and an ethylene-(meth)acrylic acid copolymer (B), and the content of component (A) and component (B) is such that, based on 100 parts by mass of the total of components (A) and (B), it is more than 80 parts by mass and 95 parts by mass or less, and 5 parts by mass or more and less than 20 parts by mass.

[0009] The cover tape described above is less prone to blocking and can be heat-sealed with less thermal energy. This prevents production line stoppages due to blocking, while enabling faster and lower-temperature heat sealing, thereby improving productivity and saving energy in the manufacturing of electronic component packaging.

[0010] The above component (A) may include a copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon, and impact-resistant polystyrene. In this case, it becomes easier to ensure stable peel strength.

[0011] The above component (B) may include an ethylene-methyl methacrylate copolymer from the viewpoint of achieving sealing properties with less thermal energy and suppressing blocking.

[0012] Another aspect of the present invention provides an electronic component packaging comprising a carrier tape having a housing section, an electronic component housed in the housing section of the carrier tape, and the above-mentioned cover tape heat-sealed to the carrier tape as a lid material. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a cover tape that can be heat-sealed with less thermal energy while suppressing the occurrence of blocking, and an electronic component packaging using the same. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view showing an embodiment of the cover tape. [Figure 2] This is a partially cutaway perspective view showing one embodiment of an electronic component packaging. [Modes for carrying out the invention]

[0015] Preferred embodiments of the present invention will be described in detail below.

[0016] [Cover tape] The cover tape of this embodiment includes at least a base layer and a heat-seal layer.

[0017] Figure 1 is a schematic cross-sectional view showing an embodiment of a cover tape. The cover tape 50 shown in Figure 1(a) comprises a base layer 1, a heat seal layer 2 provided on one side of the base layer 1, and an intermediate layer 3 provided between the base layer 1 and the heat seal layer 2. The cover tape 52 shown in Figure 1(b) has two intermediate layers 3a and 3b provided between the base layer 1 and the heat seal layer 2. The cover tape of this embodiment may have a two-layer structure without intermediate layers, or it may have a structure in which a layer such as an antistatic layer is further provided on the side of the base layer 1 opposite to the heat seal layer 2. Furthermore, the cover tape of this embodiment may have a structure in which a layer such as an antistatic layer is further provided on the side of the heat seal layer 2 opposite to the base layer 1, to the extent that the heat sealability of the heat seal layer is not impaired.

[0018] (base material layer) The base layer may be a film made from a resin composition containing one or more thermoplastic resins selected from polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyolefin resins such as polypropylene, polyamide resins such as nylon, polystyrene resins, polyethylene resins, and polycarbonate resins. From the viewpoint of mechanical strength, biaxially oriented films are preferred, and from the viewpoint of transparency and toughness, biaxially oriented polyethylene terephthalate films are more preferred.

[0019] Examples of polystyrene-based resins include polystyrene, high-impact polystyrene (HIPS), styrene-butadiene copolymer or its hydrogenated derivative, styrene-isoprene copolymer or its hydrogenated derivative, styrene-ethylene graft copolymer, styrene-butene-butadiene copolymer, methacrylic acid-styrene copolymer, and other polymers having styrene units in a molar ratio of 1 / 2 or more in their molecular chains. These can be used individually or in combination (mixture) of two or more types.

[0020] Examples of the polyethylene-based resin include low-density polyethylene, linear low-density polyethylene, ultra-low density polyethylene, ethylene-α-olefin, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid methyl copolymer, ethylene-(meth)acrylic acid ethyl copolymer, ethylene-propylene rubber, etc., and those having a molar ratio of ethylene units of 1 / 2 or more in the molecular chain. These can be used alone or in combination (as a mixture) of two or more kinds.

[0021] From the perspective of obtaining extrusion stability during film formation, various additives such as commonly used antioxidants and lubricants may be added to the base material layer.

[0022] The base material layer may be a single layer or may have a multilayer structure.

[0023] From the perspectives of mechanical strength and heat transfer during heat sealing, the thickness of the base material layer may be 5 to 100 μm, may be 10 to 80 μm, or may be 12 to 30 μm.

[0024] (Intermediate layer) The intermediate layer can be provided for the purpose of strengthening the adhesion strength between the base material layer and the heat-sealing layer and can contain a thermoplastic resin. Examples of the thermoplastic resin include (i) Polyethylene resins such as low-density polyethylene, linear low-density polyethylene, and ultra-low density polyethylene (ii) Copolymers of ethylene-1-butene, ethylene and unsaturated carboxylic acids, ethylene-(meth)acrylic acid ester copolymers, ethylene-vinyl acetate copolymers, and terpolymers with acid anhydrides, and mixtures thereof (iii) Styrene-ethylene graft copolymers, styrene-propylene graft copolymers, block copolymers of styrene-ethylene-butadiene, and mixtures thereof and the like.

[0025] For thermoplastic resins, polyethylene-based resins are preferred in terms of the above-mentioned objectives and ease of layer formation, and low-density polyethylene resins and linear low-density polyethylene resins are more preferred.

[0026] Furthermore, the intermediate layer may have a structure of two or more layers. In this case, by producing a co-extruded film of the heat seal layer and the intermediate layer, the extrusion stability of the heat seal layer can be increased, while the adhesion between the co-extruded film and the substrate layer can be improved by the other intermediate layer. The intermediate layer having a structure of two or more layers may, for example, be a first intermediate layer on the side in contact with the heat seal layer, containing one or more of the resins shown in (i), (ii), and (iii) above, and a second intermediate layer on the side in contact with the substrate layer, containing one or more of the resins shown in (i) and (ii) above.

[0027] The intermediate layer may contain various additives, such as commonly used antioxidants and lubricants, from the viewpoint of obtaining extrusion stability when forming the film.

[0028] The thickness of the intermediate layer may be 3 to 70 μm, 5 to 60 μm, or 10 to 50 μm, from the viewpoint of ensuring the adhesive strength between the base layer and the heat seal layer and the peel strength of the cover tape.

[0029] The cover tape of this embodiment may have two or more base layers and / or intermediate layers. Such a cover tape may have, for example, a three-layer structure of base layer / intermediate layer / base layer, or a four-layer structure of intermediate layer / base layer / intermediate layer / base layer.

[0030] If the cover tape of this embodiment has two or more base layers and / or intermediate layers, a known adhesive can be used to strengthen the adhesion between the layers. Examples of adhesives include isocyanate-based adhesives and ethyleneimine-based adhesives. From the viewpoint of preventing large variations in the peel strength of the cover tape, the thickness of the adhesive layer is preferably 5 μm or less.

[0031] (Heat seal layer) The heat seal layer may contain a polystyrene resin (A) (hereinafter sometimes referred to as component (A)) and an ethylene-(meth)acrylic acid copolymer (B) (hereinafter sometimes referred to as component (B)). A cover tape having such a heat seal layer makes it easy to ensure sealing performance with carrier tapes of various materials, such as polystyrene carrier tapes and polycarbonate carrier tapes.

[0032] The heat seal layer may contain, as component (A), a copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon and impact-resistant polystyrene, or a mixture thereof.

[0033] Examples of styrene-based hydrocarbons include styrene, α-methylstyrene, and various alkyl-substituted styrenes. Examples of conjugated diene hydrocarbons include butadiene and isoprene.

[0034] The heat seal layer may contain a styrene-butadiene copolymer and impact-resistant polystyrene as component (A) from the viewpoint of stabilizing the peel strength of the cover tape, and may also contain a mixture thereof.

[0035] Component (A) may also contain, from the viewpoint of adjusting peel strength and film-forming properties, a block copolymer (A-1) (hereinafter also referred to as component (A-1)) of 50% to 95% by mass of styrene hydrocarbons and 5% to 50% by mass of conjugated diene hydrocarbons, a block copolymer (A-2) (hereinafter also referred to as component (A-2)) of 10% to less than 50% by mass of styrene hydrocarbons and more than 50% by mass and 90% by mass of conjugated diene hydrocarbons, and impact-resistant polystyrene (A-3) (hereinafter also referred to as component (A-3)). In this case, the respective content ratios may be 20 to 40 parts by mass of component (A-1), 35 to 60 parts by mass of component (A-2), and 5 to 15 parts by mass of component (A-3) per 100 parts by mass of the total of components (A-1), (A-2), and (A-3).

[0036] Examples of ethylene-(meth)acrylic acid copolymers (B) include ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and ethylene-glycidyl methacrylate-methyl acrylate copolymer (EGMA-MA). These can be used individually or in combination (mixture) of two or more.

[0037] (B) The ethylene content of component (B) may be 60-95% by mass or 65-90% by mass, from the viewpoint of achieving sealing performance with less thermal energy and suppressing blocking.

[0038] The heat seal layer may contain various additives, such as commonly used antioxidants and lubricants, from the viewpoint of obtaining extrusion stability when forming the film.

[0039] From the viewpoint of suppressing the occurrence of blocking and enabling heat sealing with less thermal energy, the content of component (A) and component (B) in the heat seal layer may be more than 80 parts by mass and 95 parts by mass or less, and 5 parts by mass or more and less than 20 parts by mass, respectively, per 100 parts by mass of the total of component (A) and component (B), and may also be 82 parts by mass or more and 95 parts by mass or less, and 5 parts by mass or more and 18 parts by mass or less. Furthermore, from the viewpoint of dispensing, the content of component (A) and component (B) in the heat seal layer may be 84 parts by mass or more and 95 parts by mass or less, and 5 parts by mass or more and 16 parts by mass or less, respectively, per 100 parts by mass of the total of component (A) and component (B), and may also be 85 parts by mass or more and 95 parts by mass or less, and 5 parts by mass or more and 15 parts by mass or less.

[0040] The total content of component (A) and component (B) in the heat seal layer may be 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass, based on the total amount of the heat seal layer.

[0041] Each of the aforementioned layers can be formed into a film by methods such as the inflation method, T-die method, casting method, or calendering method. In this case, each component constituting each layer is blended using a mixer such as a Henschel mixer, tumbler mixer, or mazerer, and this is directly formed into a film using an extruder, or the blend can be kneaded and extruded once using a single-screw or twin-screw extruder to obtain pellets, and then the pellets can be further extruded into a film using an extruder.

[0042] The heat seal layer may be formed by methods such as blown molding or extrusion molding such as T-die extrusion to form a film, by dissolving the above-mentioned components (A) and (B) in a solvent and coating it onto the film of the base layer, or by coating it as an aqueous emulsion.

[0043] When manufacturing a film for a heat seal layer by extrusion molding, it is preferable to co-extrude the intermediate layer to improve extrusion stability. For example, the resin constituting the intermediate layer and the resin constituting the heat seal layer can be melt-kneaded using separate single-screw or twin-screw extruders, laminated and integrated via a feed block or multi-manifold die, and then extruded from a T-die to obtain a two-layer film in which the intermediate layer and the heat seal layer are laminated.

[0044] Furthermore, the heat-sealing film obtained by extrusion molding may be laminated with a base layer using common methods such as dry lamination or extrusion lamination to form a cover tape.

[0045] The overall thickness of the cover tape can be 30 to 100 μm, 35 to 80 μm, or 40 to 70 μm. Within this range, it is easy to ensure the strength and sealing properties of the tape.

[0046] The cover tape of this embodiment is suitable for packaging electronic components. Examples of electronic components include ICs, LEDs (light-emitting diodes), resistors, liquid crystals, capacitors, transistors, piezoelectric resistors, filters, crystal oscillators, diodes, connectors, switches, potentiometers, relays, inductors, and the like. The electronic components may be intermediate products using the above components, or they may be final products.

[0047] For the above applications, it is preferable to impart antistatic properties to the base layer and heat seal layer in order to prevent dust adhesion and dissipate the static charge of the cover tape itself. Commonly used antistatic agents that impart antistatic properties include surfactant-type agents, conductive metal oxide nanoparticles, and electronically conductive polymers. These antistatic agents can be kneaded into the resin depending on the desired performance, but from the viewpoint of efficiently exhibiting their effects, they can be coated onto both surface layers of the cover tape using a gravure coater or similar method.

[0048] Cover tapes for electronic component packaging can, for example, be heat-sealed to carrier tapes.

[0049] The carrier tape may have pockets for housing electronic components, formed by methods such as pressure molding or vacuum forming. Suitable materials for the carrier tape include easily moldable materials such as polyvinyl chloride (PVC), polystyrene (PS), polyester (A-PET, PEN, PET-G, PCTA), polypropylene (PP), polycarbonate (PC), polyacrylonitrile (PAN), and acrylonitrile-butadiene-styrene copolymer (ABS). These resins can be used individually or in combination. The carrier tape may also be a laminate consisting of multiple layers.

[0050] The cover tape of this embodiment can be used in combination with carrier tapes such as polystyrene carrier tape or polycarbonate carrier tape.

[0051] <Electronic component packaging> The electronic component packaging of this embodiment comprises a carrier tape having a housing portion capable of housing electronic components, electronic components housed in the housing portion of the carrier tape, and a cover tape of this embodiment heat-sealed to the carrier tape as a lid material.

[0052] Figure 2 is a partially cutaway perspective view showing one embodiment of an electronic component packaging. The electronic component packaging 200 shown in Figure 2 comprises an embossed carrier tape 16 with a housing section 20, an electronic component 40 housed in the housing section 20, and a cover film 50 heat-sealed to the embossed carrier tape 16. The embossed carrier tape 16 is provided with feed holes 30 that can be used for transporting various electronic components such as ICs during the encapsulation process. In addition, a hole (not shown) for inspecting the electronic component is provided at the bottom of the housing section 20.

[0053] Examples of electronic components and carrier tapes include those mentioned above.

[0054] The electronic component packaging of this embodiment can be used as a carrier tape wound on a reel for storing and transporting electronic components.

[0055] The electronic component packaging of this embodiment can be manufactured by a method that includes the step of heat-sealing the cover tape of this embodiment onto a carrier tape in which the electronic components are housed in the housing section.

[0056] For heat sealing of cover tape, a component called a sealing iron can be used, which can apply a predetermined amount of heat and a predetermined pressure to the heat sealing layer. The cover tape can be heat-sealed to the surface of the carrier tape by pressing such a sealing iron onto the carrier tape from above the cover tape. Specifically, methods such as a repetitive sealing method in which the sealing iron is pressed multiple times while the embossed carrier tape is being transported, or a continuous sealing method in which the sealing iron is continuously applied to the cover tape to heat seal it, can be applied.

[0057] The sealing temperature may be 100-240°C or 120-220°C.

[0058] According to the manufacturing method described above, by using the cover tape of this embodiment, it becomes possible to speed up and lower the temperature of heat sealing, thereby improving productivity and saving energy in the manufacturing of electronic component packaging. [Examples]

[0059] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0060] (Example 1) As a polystyrene-based resin, 35 parts by mass of styrene-butadiene copolymer (manufactured by Denka Co., Ltd., product name "Clearlen 170ZR", styrene / butadiene mass ratio = 83 / 17), 55 parts by mass of styrene-butadiene copolymer (manufactured by JSR Corporation, product name "TR2000", styrene / butadiene mass ratio = 40 / 60), 5 parts by mass of high-impact polystyrene (manufactured by Toyo Styrene Co., Ltd., product name "HIPS H870"), and as an ethylene-(meth)acrylic acid copolymer, 5 parts by mass of ethylene-methyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., product name "Aclift WH303-F", methyl methacrylate content: 18% by mass, ethylene content: 82% by mass) were kneaded in a twin-screw extruder to obtain a resin composition constituting the heat seal layer. This resin composition and linear low-density polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., product name "Yumerit 2040F") as the first intermediate layer were co-extruded using the T-die method to obtain a two-layer film (total thickness 30 μm) consisting of a first intermediate layer (thickness 20 μm) and a heat-seal layer (thickness 10 μm). This two-layer film was laminated with a biaxially oriented polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name "Ester Film E5100", thickness 16 μm) via a second intermediate layer (thickness 13 μm) made of low-density polyethylene resin using the extrusion lamination method to obtain the cover tape of Example 1.

[0061] (Examples 2-8, Comparative Examples 1-3) Cover tapes for Examples 2-8 and Comparative Examples 1-3 were obtained in the same manner as in Example 1, except that the polystyrene resin and ethylene-(meth)acrylic acid copolymer were used in the compositions shown in Table 1.

[0062] The details of the raw materials shown in Table 1 are as follows. SBC: Styrene-butadiene copolymer (manufactured by Denka Co., Ltd., product name "ClearLen 170ZR", styrene / butadiene mass ratio = 83 / 17) SBR: Styrene-butadiene copolymer (manufactured by JSR Corporation, product name "TR2000", styrene / butadiene mass ratio = 40 / 60) HIPS: High-impact polystyrene (manufactured by Toyo Styrene Co., Ltd., product name "HIPS H870") EMMA: Ethylene-methyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., product name "Aclift WH303-F", methyl methacrylate content: 18% by mass, ethylene content: 82% by mass) EGMA-MA: Ethylene-glycidyl methacrylate-methyl acrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., product name "BondFirst BF-7M", glycidyl methacrylate content: 6% by mass, methyl acrylate content: 27% by mass, ethylene content: 67% by mass) EMA: Ethylene-methyl acrylate copolymer (manufactured by Nippon Polyethylene Co., Ltd., product name "Rexpearl EB240H", methyl acrylate content: 20% by mass, ethylene content: 80% by mass) EEA: Ethylene-ethyl acrylate copolymer (manufactured by Ube Maruzen Polyethylene Co., Ltd., product name "UBE Polyethylene ZE735", ethyl acrylate content: 19% by mass, ethylene content: 81% by mass)

[0063] The cover tapes for each example and comparative example were evaluated using the following method. The results are shown in Table 1.

[0064] [Evaluation of low-temperature sealing performance] Using a taping machine (Nagata Seiki Co., Ltd., product name "NK-600"), a 21.5 mm wide cover tape was heat-sealed onto a 24 mm wide polystyrene carrier tape (Denka Co., Ltd., product name "EC-R") under the following conditions: seal head width 0.5 mm x 2, seal head length 24 mm, seal pressure 0.5 kgf, feed length 12 mm, seal time 0.3 seconds, and seal iron temperature 140°C. Subsequently, under conditions of 23°C and 50% relative humidity, the peel strength was measured when the cover tape was peeled at a peeling speed of 300 mm per minute at a peeling angle of 170° to 180°, and the low-temperature sealability was evaluated according to the following criteria. <Judgment criteria> A: Peel strength of 0.2N or higher C: Peel strength less than 0.2N

[0065] [Evaluation of blocking resistance] A 21.5mm wide record-wound cover tape was left undisturbed for one day in an atmosphere of 23°C and 50% relative humidity. After that, it was unwound at a speed of 2000mm per minute, and the load during unwinding was measured with a digital force gauge.

[0066] Furthermore, the cover tape was manually unwound to check for blocking and evaluated for blocking resistance according to the following criteria. A: No blocking B: There is blocking in some places. C: There is blocking throughout.

[0067] [Table 1]

[0068] As shown in Table 1, the cover tapes of Examples 1 to 8 were confirmed to enable heat sealing with less thermal energy while suppressing the occurrence of blocking.

[0069] On the other hand, the cover tape of Comparative Example 1, in which the heat seal layer did not contain an ethylene-(meth)acrylic acid copolymer, had low peel strength when sealed at low temperatures. The cover tapes of Comparative Examples 2 and 3, in which the ethylene-(meth)acrylic acid copolymer content in the heat seal layer exceeded the range according to the present invention, had a large load during dispensing and also experienced blocking. [Explanation of Symbols]

[0070] 1...Base layer, 2...Heat seal layer, 3,3a,3b...Intermediate layer, 16...Embossed carrier tape, 20...Housing section, 30...Feed hole, 40...Electronic component, 50,52...Cover tape, 200...Electronic component packaging.

Claims

1. It comprises at least a base layer and a heat seal layer, The heat seal layer contains a polystyrene resin (A) and an ethylene-(meth)acrylic acid copolymer (B), The aforementioned component (A) comprises a copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon, and impact-resistant polystyrene. The content of component (A) and component (B) is such that, with respect to 100 parts by mass of the total of component (A) and component (B), it is greater than 80 parts by mass and 95 parts by mass or less, and 5 parts by mass or more and less than 20 parts by mass. A cover tape in which the heat-seal layer does not contain a hydrogenated resin of a block copolymer of an aromatic vinyl compound and a conjugated diene hydrocarbon compound.

2. The cover tape according to claim 1, wherein the (B) component comprises an ethylene-methyl methacrylate copolymer.

3. The cover tape according to claim 1 or 2, wherein the component (A) comprises, as the copolymer, a block copolymer (A-1) of 50% to 95% by mass of styrene hydrocarbons and 5% to 50% by mass of conjugated diene hydrocarbons, and a block copolymer (A-2) of 10% to less than 50% by mass of styrene hydrocarbons and more than 50% by mass and 90% by mass or less of conjugated diene hydrocarbons.

4. An electronic component packaging comprising: a carrier tape having a storage section; an electronic component housed in the storage section of the carrier tape; and a cover tape according to any one of claims 1 to 3, heat-sealed to the carrier tape as a lid material.

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