Cover tape and electronic component packaging

Abstract

To provide a cover tape that has sufficient blocking resistance and can reduce the peel strength range, and an electronic component packaging using the same. [Solution] The cover tape comprises at least a base layer and a heat seal layer, the heat seal layer containing a copolymer (A) of styrene hydrocarbons and conjugated diene hydrocarbons, and component (A) comprises a block copolymer (A-1) of 10% by mass or more and less than 50% by mass of styrene hydrocarbons and more than 50% by mass and 90% by mass or less of conjugated diene hydrocarbons, and a block copolymer (A-2) of 50% by mass or more and 95% by mass or less of styrene hydrocarbons and 5% by mass or more and 50% by mass or less of conjugated diene hydrocarbons, the content of component (A-1) is 35 to 60% by mass based on the total amount of the heat seal layer, and the mass ratio of component (A-2) to component (A-1) is 0.30 to 1.0.

Description

Technical Field

[0006] , ,

[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 high-performance. 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).

[0004] When using an electronic component package, the cover tape is peeled off from the carrier tape, and the electronic components are automatically taken out and surface-mounted on an electronic circuit board. <00000​​​​​​​​​​​​​​​​​​​​​In recent years, electronic components have become significantly smaller, thinner, and lighter. However, in the process of mounting electronic components onto electronic circuit boards, if the difference between the maximum and minimum peel strength (hereinafter referred to as the "peel strength range") becomes too large when peeling the cover tape from the carrier tape, the carrier tape vibrates violently, causing the electronic components to fly off and increasing the likelihood of mounting defects.

[0007] Therefore, the inventors focused on the heat-seal layer of the cover tape and investigated the design of a heat-seal layer to reduce the peel strength range. Furthermore, since cover tapes are generally supplied in wound form when manufacturing electronic component packaging, blocking resistance also needs to be considered.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a cover tape that has sufficient blocking resistance and can reduce the peel strength range, and an electronic component packaging using the same. [Means for solving the problem]

[0009] 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 copolymer (A) of a styrene hydrocarbon and a conjugated diene hydrocarbon, and component (A) comprises a block copolymer (A-1) of 10% by mass or more and less than 50% by mass of styrene hydrocarbon and more than 50% by mass and 90% by mass or less of conjugated diene hydrocarbon, and a block copolymer (A-2) of 50% by mass or more and 95% by mass or less of styrene hydrocarbon and 5% by mass or more and 50% by mass or less of conjugated diene hydrocarbon, wherein the content of component (A-1) is 35 to 60% by mass based on the total amount of the heat seal layer, and the mass ratio of component (A-2) to component (A-1) is 0.30 to 1.0.

[0010] The above-mentioned cover tape is less prone to blocking even when wound into a coil, and when peeled off after heat sealing, it can reduce the peel strength range. As a result, in the manufacturing of electronic component packaging, it is possible to suppress unwinding defects from the coil, and in the manufacturing of electronic equipment, when peeling the cover tape off the electronic component packaging, it is possible to prevent electronic components from flying out and prevent mounting defects on the electronic circuit board.

[0011] The heat-seal layer described above may further contain an ethylene polymer (B) from the viewpoint of making it easier to achieve sealing properties with less thermal energy and from the viewpoint of suppressing blocking.

[0012] In addition to the points mentioned above, component (B) may also contain one or more of ethylene-α-olefin copolymers and ethylene-(meth)methyl acrylate copolymers from the viewpoint of film-forming properties.

[0013] 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.

[0014] The above-mentioned electronic component packaging can have a narrow peel strength range when removing the cover tape. This can significantly reduce the failure rate of electronic component mounting in the manufacturing of electronic devices. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a cover tape that has sufficient blocking resistance and can reduce the peel strength range, and an electronic component packaging body using the same. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view showing an embodiment of the cover tape. [Figure 2]It is a partially cut-away perspective view showing an embodiment of an electronic component package. [Figure 3] It is a diagram for explaining the peel strength range.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail.

[0018] [Cover Tape] The cover tape of this embodiment includes at least a base material layer and a heat-sealing layer.

[0019] FIG. 1 is a schematic cross-sectional view showing an embodiment of the cover tape. The cover tape 50 shown in (a) of FIG. 1 includes a base material layer 1, a heat-sealing layer 2 provided on one surface side of the base material layer 1, and an intermediate layer 3 provided between the base material layer 1 and the heat-sealing layer 2. Further, the cover tape 52 shown in (b) of FIG. 1 has two intermediate layers 3a and 3b provided between the base material layer 1 and the heat-sealing layer 2. The cover tape of this embodiment may have a two-layer structure without an intermediate layer, and may have a structure further including a layer such as an antistatic layer on the side of the base material layer 1 opposite to the heat-sealing layer 2. Also, the cover tape of this embodiment may have a structure further including a layer such as an antistatic layer on the side of the heat-sealing layer 2 opposite to the base material layer 1 within a range where the heat-sealing property of the heat-sealing layer is not impaired.

[0020] (Base Material Layer) The base material layer may be a film formed 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, these films are preferably biaxially stretched films, and more preferably biaxially stretched polyethylene terephthalate films from the viewpoints of transparency and toughness.

[0021] Examples of polystyrene resins include polystyrene, high impact polystyrene (HIPS), styrene-butadiene copolymers or hydrogenated products thereof, styrene-isoprene copolymers or hydrogenated products thereof, graft copolymers of styrene and ethylene, styrene-butene-butadiene copolymers, copolymers of methacrylic acid and styrene, etc., and polymers having a styrene unit in a molar ratio 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.

[0022] Examples of polyethylene resins 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)methyl acrylate copolymer, ethylene-(meth)ethyl acrylate copolymer, ethylene-propylene rubber, etc., and those having an ethylene unit in a molar ratio 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.

[0023] From the viewpoint of obtaining extrusion stability when forming the film, various additives such as commonly used antioxidants and lubricants may be added to the base material layer.

[0024] The base material layer may be a single layer or may have a multilayer structure.

[0025] From the viewpoints of mechanical strength and heat transfer properties 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.

[0026] (Intermediate layer) The intermediate layer can be provided for the purpose of strengthening the adhesion strength between the base material layer and the heat seal 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) Ethylene-1-butene, copolymers of ethylene and unsaturated carboxylic acids, ethylene-(meth)acrylic acid copolymers, ethylene-vinyl acetate copolymers, and terpolymers with acid anhydrides, and mixtures thereof. (iii) Styrene-ethylene graft copolymers, styrene-propylene graft copolymers, styrene-ethylene-butadiene block copolymers, and mixtures thereof These are some examples.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] (Heat seal layer) The heat-seal layer contains a copolymer (A) of styrene hydrocarbons and conjugated diene hydrocarbons (hereinafter sometimes referred to as component (A)).

[0034] Examples of styrene-based hydrocarbons include styrene, α-methylstyrene, and various alkyl-substituted styrenes. Examples of conjugated diene hydrocarbons include butadiene and isoprene.

[0035] Component (A) may include a block copolymer (A-1) (hereinafter sometimes referred to as component (A-1)) of 10% to less than 50% by mass of styrene hydrocarbons and more than 50% to 90% by mass of conjugated diene hydrocarbons, and a block copolymer (A-2) (hereinafter sometimes referred to as component (A-2)) of 50% to 95% by mass of styrene hydrocarbons and more than 5% to 50% by mass of conjugated diene hydrocarbons.

[0036] Examples of component (A-1) include styrene-butadiene copolymer, styrene-butylene-butylene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, and styrene-isoprene-styrene copolymer. Component (A-1) can be used individually or in combination of two or more.

[0037] The mass ratio of styrene hydrocarbons to conjugated diene hydrocarbons in component (A-1) may be 10 / 90 to 45 / 55, 30 / 70 to 45 / 55, or 35 / 75 to 45 / 55, from the viewpoint of easily adjusting the peel strength and the film-forming properties.

[0038] From the viewpoint of reducing the peel strength range and improving blocking resistance, the content of component (A-1) can be 35 to 60% by mass, 40 to 55% by mass, or 40 to 50% by mass, based on the total amount of the heat seal layer.

[0039] Examples of component (A-2) include styrene-butadiene copolymer, styrene-butylene-butylene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, and styrene-isoprene-styrene copolymer. Component (A-2) can be used individually or in combination of two or more.

[0040] The mass ratio of styrene hydrocarbons to conjugated diene hydrocarbons in component (A-2) may be 50 / 50 to 95 / 5, 70 / 30 to 90 / 10, or 80 / 20 to 85 / 15.

[0041] From the viewpoint of reducing the peel strength range and improving blocking resistance, the mass ratio of component (A-2) to component (A-1) can be 0.30 to 1.0, may be 0.50 to 0.90, or may be 0.65 to 0.85.

[0042] The total content of components (A-1) and (A-2) in the heat seal layer may be 50-100% by mass, 60-100% by mass, or 70-90% by mass, based on the total amount of the heat seal layer, from the viewpoint of film formation properties and blocking resistance of the film.

[0043] The heat seal layer may contain polystyrene resins other than component (A). Examples of such polystyrene resins include high-impact polystyrene, general-purpose polystyrene, acrylonitrile-butadiene-styrene copolymer, and styrene-ethylene-propylene-styrene copolymer.

[0044] (A) The content of polystyrene resins other than component (A) may be greater than 0% by mass and less than or equal to 25% by mass, 5 to 20% by mass, or 5 to 10% by mass, based on the total amount of the heat seal layer, from the viewpoint of blocking resistance.

[0045] If the heat seal layer contains component (A-1), component (A-2), and impact-resistant polystyrene (hereinafter sometimes referred to as component (A-3)), the respective content ratios may be 35 to 60 parts by mass of component (A-1), 20 to 40 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).

[0046] The heat seal layer may further contain an ethylene polymer (B) (hereinafter sometimes referred to as component (B)) from the viewpoint of making it easier to achieve sealing properties with less thermal energy and suppressing blocking.

[0047] In addition to the points mentioned above, component (B) may include ethylene-α-olefin copolymer (B-1) (hereinafter sometimes referred to as component (B-1)) and ethylene-(meth)acrylic acid copolymer (B-2) (hereinafter sometimes referred to as component (B-2)) from the viewpoint of film formation properties. The heat seal layer may contain one or both of component (B-1) and component (B-2). Furthermore, component (B) may contain one or more of ethylene-α-olefin copolymer and ethylene-(meth)acrylate copolymer from the viewpoints of making it easier to achieve sealing properties with less thermal energy, suppressing blocking, and film formation properties.

[0048] Examples of α-olefins in ethylene-α-olefin copolymers include propylene, butene, pentene, and hexene.

[0049] As component (B-1), a random copolymer can be used, which has a structure in which the ethylene component and the α-olefin component are arranged in a disordered manner. Examples of such copolymers include ethylene-butene-1 random copolymer and ethylene-propylene-1 random copolymer.

[0050] Component (B-1) may have an ethylene content of 50-95% by mass, 70-95% by mass, or 80-95% by mass, from the viewpoint of making it easier to achieve sealing properties with less thermal energy and suppressing blocking.

[0051] (B-2) Examples of components 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 of two or more (as a mixture).

[0052] Component (B-2) may have an ethylene content ratio of 60-95% by mass or 65-90% by mass, from the viewpoint of making it easier to exhibit sealing properties with less thermal energy and suppressing blocking, and may be an ethylene-(meth)acrylate methyl copolymer having such an ethylene content ratio.

[0053] The content of component (B) may be 5 to 20% by mass or 10 to 15% by mass, based on the total amount of the heat seal layer.

[0054] 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.

[0055] From the viewpoint of reducing the peel strength range and improving blocking resistance, the total content of component (A) and component (B) in the heat seal layer may be 70 to 100% by mass or 90 to 100% by mass, based on the total amount of the heat seal layer.

[0056] 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.

[0057] 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 component (A), and optionally component (B) and other components in a solvent and coating the film of the base layer, or by coating it as an aqueous emulsion.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Cover tapes for electronic component packaging can, for example, be heat-sealed to carrier tapes.

[0064] 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.

[0065] The cover tape of this embodiment can be used in combination with carrier tapes such as polystyrene carrier tape or polycarbonate carrier tape.

[0066] <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.

[0067] 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.

[0068] Examples of electronic components and carrier tapes include those mentioned above.

[0069] The electronic component packaging of this embodiment can be used as a carrier tape wound on a reel for storing and transporting electronic components.

[0070] The electronic component packaging of this embodiment can be manufactured by a method that includes a step of heat-sealing the cover tape of this embodiment onto a carrier tape in which electronic components are housed in a housing section. Since the cover tape of this embodiment has sufficient blocking resistance, blocking is less likely to occur even when it is made into a wound body, poor unwinding from the wound body can be suppressed, and the heat-sealing process can be carried out efficiently.

[0071] 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.

[0072] The sealing temperature may be between 100 and 240°C, or between 120 and 220°C.

[0073] The electronic component packaging of this embodiment can have a smaller peel strength range when peeling off the cover tape. This makes it possible to significantly reduce the mounting defect rate of electronic components in the manufacturing of electronic devices.

[0074] Figure 3 shows an example of a peel strength chart obtained when a cover tape is peeled in the longitudinal direction. In the peel strength chart shown in Figure 3(a), the peel strength changes significantly in the longitudinal direction of the tape, and the peel strength range R1 exceeds 0.25 N. On the other hand, in the peel strength chart shown in Figure 3(b), the peel strength range R2 is less than 0.15 N, and such a cover tape is less likely to cause problems such as electronic components flying out due to vibration during peeling compared to the cover tape in (a). [Examples]

[0075] 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.

[0076] (Example 1) As component (A-1), 45 parts by mass of styrene-butadiene copolymer (manufactured by JSR Corporation, product name "TR2000", styrene / butadiene mass ratio = 40 / 60), as component (A-2), 25 parts by mass of styrene-butadiene copolymer (manufactured by Denka Co., Ltd., product name "Clearlen 170ZR", styrene / butadiene mass ratio = 83 / 17), as component (A-3), 10 parts by mass of high-impact polystyrene (manufactured by Toyo Styrene Co., Ltd., product name "HIPS H870"), and as an ethylene-α-olefin copolymer, 20 parts by mass of ethylene-1-butene random copolymer (manufactured by Mitsui Chemicals, Inc., product name "Tafmer A-4085S") 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.

[0077] (Examples 2-12, Comparative Examples 1-4) Cover tapes for Examples 2-12 and Comparative Examples 1-4 were obtained in the same manner as in Example 1, except that the polystyrene copolymer (components (A-1), (A-2), and (A-3)) and the ethylene copolymer were used in the compositions shown in Tables 1 and 2.

[0078] The details of the raw materials shown in Table 1 are as follows. SBR: Styrene-butadiene copolymer (manufactured by JSR Corporation, product name "TR2000", styrene / butadiene mass ratio = 40 / 60) SBC: Styrene-butadiene copolymer (manufactured by Denka Co., Ltd., product name "ClearLen 170ZR", styrene / butadiene mass ratio = 83 / 17) HIPS: High-impact polystyrene (manufactured by Toyo Styrene Co., Ltd., product name "HIPS H870") EB: Ethylene-1-butene random copolymer (manufactured by Mitsui Chemicals, Inc., product name "Tafmer A-4085S") 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)

[0079] The cover tapes for each example and comparative example were evaluated using the following method. The results are shown in Tables 1 and 2.

[0080] [Evaluation of Peel Strength Range] 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, and seal time 0.3 seconds, to obtain taping samples. The heat sealing temperature for each cover tape was determined by adjusting it so that the average peel strength obtained from the peel strength chart was 0.4 N (±0.03 N).

[0081] For the obtained taping samples, the cover tape was peeled longitudinally at a peeling angle of 170° to 180° at a peeling speed of 300 mm per minute under conditions of 23°C and 50% relative humidity. From the peel strength chart obtained when 100 mm was peeled, the difference between the maximum and minimum peel strength values ​​was calculated, and the peel strength range was evaluated according to the following criteria. <Judgment criteria> A: The difference between the maximum and minimum peel strength is less than 0.15 N. B: The difference between the maximum and minimum peel strength is 0.15 N or more.

[0082] [Evaluation of blocking resistance] A 21.5mm wide record-wound cover tape was left standing for one day in an atmosphere of 23°C and 50% relative humidity. Afterward, it was unwound at a speed of 2000mm per minute, and the load during unwinding was measured using a digital force gauge. The blocking resistance was evaluated based on the unwinding load according to the following criteria. <Judgment criteria> A: Load during unwinding is less than 100mN B: Load during unwinding is 100mN or more

[0083] [Table 1]

[0084] [Table 2]

[0085] As shown in Tables 1 and 2, the cover tapes of Examples 1 to 12, in which the content of component (A-1) was 35 to 60% by mass and the mass ratio of component (A-2) to component (A-1) was 0.30 to 1.0, were confirmed to have sufficient blocking resistance while suppressing the peel strength range to 0.15 N or less. [Explanation of Symbols]

[0086] 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 copolymer (A) of a styrene hydrocarbon and a conjugated diene hydrocarbon, The aforementioned component (A) includes a block copolymer (A-1) of 10% by mass or more and less than 50% by mass of styrene hydrocarbons and more than 50% by mass and 90% by mass or less of conjugated diene hydrocarbons, and a block copolymer (A-2) of 50% by mass or more and 95% by mass or less of styrene hydrocarbons and 5% by mass or more and 50% by mass or less of conjugated diene hydrocarbons. The content of component (A-1) is 35 to 60% by mass, based on the total amount of the heat seal layer. A cover tape in which the mass ratio of component (A-2) to component (A-1) is 0.30 to 1.

0.

2. The cover tape according to claim 1, wherein the heat seal layer further contains an ethylene polymer (B).

3. The cover tape according to claim 2, wherein the component (B) comprises one or more of ethylene-α-olefin copolymers and ethylene-(meth)acrylate methyl copolymers.

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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