TW202408889A - Cover tape and electronic component packaging body including same - Google Patents

Abstract

The present invention addresses the problem of providing a cover tape to which an electronic component is less likely to adhere when the cover tape is released to extract the electronic component. This cover tape comprises an insulative heat seal layer provided on one surface and a conductive layer directly laminated on the heat seal layer, wherein a heat seal layer side has a surface resistivity of 1 * 1010[Omega] / □ or less, and the heat seal layer has a thickness of less than 600 nm.

Description

Cover tape and electronic component packaging body containing the same

The present invention relates to a cover tape and an electronic component packaging body containing the cover tape.

Along with the miniaturization of electronic equipment, there has been progress in miniaturization and high performance of electronic components used, and in the assembly process of electronic equipment, a step of automatically mounting the components on a printed circuit board is performed. This type of surface-mounted electronic component is accommodated in a carrier tape that has pockets continuously formed by thermal formation according to the shape of the electronic component. After storing the electronic components, overlap the cover tape as the cover material on the top surface of the carrier tape, and then use the heated sealing rod to continuously heat seal the two ends of the cover tape in the length direction to form a package.

In recent years, various electronic components such as capacitors, resistors, ICs, LEDs, connectors, and switching components have been significantly reduced in size, weight, and thickness. When peeling off the cover tape in order to take out the contained electronic components from the aforementioned package, The required performance is more stringent than in the past. In addition, static electricity generated when the cover tape is peeled off from the carrier tape in order to take out the electronic components can easily cause problems during the installation process when the electronic components adhere to the cover tape and fly out. Therefore, antistatic measures against carrier tapes and cover tapes have become an important issue.

In the cover tape currently on the market, as a countermeasure against static electricity, a conductive agent such as conductive tin oxide is added to the heat seal layer to suppress the adhesion of parts (Patent Document 1).

Patent Document 1: International Publication No. 2019/087999

However, in the method of adding a conductive agent to the heat seal layer, the frictional charging of the electronic components sometimes causes inductive charging in the heat seal layer, thereby generating charges on the surface of the heat seal layer. When charges are generated, electrostatic attraction is generated, which may become the main cause of the adhesion of electronic components, so sometimes the static electricity countermeasure is not satisfactory. In view of the above situation, the present invention aims to provide a cover tape that reduces the risk of electronic components adhering to the cover tape when the cover tape is peeled off to remove the electronic components.

As a result of in-depth research on the above-mentioned subject, the present inventors found that by providing an insulating heat sealing layer on one surface instead of providing a heat sealing layer containing a conductive agent, and by providing a conductive layer directly laminated on the heat sealing layer, Furthermore, the surface resistivity of the heat sealing layer side is 1×10 ¹⁰ Ω/□ or less, and the thickness of the heat sealing layer is less than 600 nm, so that the generation of electrostatic attraction between the heat sealing layer and the electronic component can be suppressed, thereby completing the present invention. .

The present invention for solving the above problems is composed of the following: (1) A cover tape having an insulating heat sealing layer provided on one surface and a conductive layer directly laminated on the heat sealing layer, wherein the heat sealing layer The surface resistivity on the layer side is 1×10 ¹⁰ Ω/□ or less; the average thickness of the heat sealing layer is less than 600 nm; (2) The cover tape as described in (1), wherein the conductive layer contains resin and conductive agent. (3) The cover tape as described in (1) or (2), wherein the conductive agent is selected from the group consisting of conductive tin oxide particles, conductive polymers and carbon nanomaterials; (4) As in (4) 2) The cover tape described in (3), wherein the conductive layer contains 65 to 95% by mass of a conductive agent, and the conductive agent is conductive tin oxide particles; (5) As described in (3) or (4) The cover tape, wherein the conductive tin oxide particles are antimony-doped tin dioxide (ATO); (6) The cover tape as described in any one of (1) to (5), which has a heat sealing layer in sequence, Conductive layer and base material layer; (7) The cover tape as described in any one of (1) to (6), which has a heat sealing layer, a conductive layer, an intermediate layer, and a base material layer in order; (8) ) The cover tape as described in any one of (1) to (7), wherein the thickness of the heat sealing layer is 30 to 250 nm; (9) The cover as described in any one of (1) to (8) A tape used as a cover material for an electronic component package; (10) An electronic component package including: a carrier tape and a cover tape as described in any one of (1) to (9).

According to the present invention, it is possible to obtain a cover tape in which there is little risk that electronic components will adhere to the cover tape when the cover tape is peeled off in order to take out the electronic components.

Various embodiments of the cover tape will be described below, followed by a method for manufacturing the cover tape. However, if a specific description of one embodiment is also applicable to other embodiments, the description will be omitted in the other embodiments.

[First embodiment] The cover tape according to the first embodiment of the present invention is a cover tape having an insulating heat-sealing layer provided on one surface and a conductive layer directly laminated on the heat-sealing layer, wherein the surface resistivity of the heat-sealing layer side is 1×10 ¹⁰ Ω/□ or less, and the average thickness of the heat-sealing layer is less than 600nm. The structure of the cover tape of this embodiment is shown in FIG1. The cover tape 1 shown in FIG1 is provided with a heat-sealing layer 2, a conductive layer 3, and a base material layer 4 in sequence. In the cover tape 1, the heat-sealing layer 2 constitutes one of the surfaces, and the base material layer 4 constitutes the other surface.

(Heat sealing layer) The heat seal layer is a layer that has the function of being welded to another resin by heat. As shown in Figure 1, it is a layer constituting one surface of the cover tape. The heat sealing layer preferably contains thermoplastic resin as its main component. Here, the meaning of "as a main component" means that it contains more than 50% by mass in the resin. In one embodiment, the resin of the heat sealing layer may contain 70 mass% or more, or 90 mass% or more of the thermoplastic resin. As the thermoplastic resin constituting the heat sealing layer, polyolefin resin, acrylic resin, styrene-acrylic acid copolymer, etc. can be used. Acrylic resin is a resin containing at least a structure derived from an acrylic monomer in a repeating unit. Specific examples of the acrylic monomer include acrylic esters such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, Methacrylates such as butyl methacrylate, cyclohexyl methacrylate, etc. These acrylic monomers may be used individually or in combination of two or more types. Styrene-acrylic copolymer is a copolymer with styrene-based monomer and (meth)acrylic-based monomer as the main components. Examples of styrene-based monomers include: styrene, α-methylstyrene , o-methylstyrene, m-methylstyrene, p-methylstyrene, p-phenylstyrene, etc., especially styrene is preferred. These styrenic monomers can be used alone or in combination of two or more. Examples of the (meth)acrylic monomer include acrylic esters such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate; methyl methacrylate, ethyl methacrylate, and propyl methacrylate. , butyl methacrylate, cyclohexyl methacrylate and other methacrylates, etc. These (meth)acrylic monomers can be used alone or in combination of two or more. In addition to the styrene-based monomer and the (meth)acrylic acid-based monomer, other monomers copolymerizable with these monomers may also be copolymerized in a small amount.

The aforementioned resin containing styrene-acrylic copolymer as its main component has extremely excellent heat sealability with respect to polystyrene, polycarbonate, etc., which are materials constituting the carrier tape. In particular, a resin whose main component is a styrene-acrylic copolymer having a mass average molecular weight of 5,000 to 80,000, preferably 10,000 to 50,000 is used. If the mass average molecular weight is 5,000 or more, installation problems in which storage parts adhere to the heat-sealing layer due to stickiness can be suppressed. On the other hand, if the mass average molecular weight is 80,000 or less, breakage due to significant increase in peel strength when the peel speed increases can be suppressed. In addition, the glass transition temperature of the styrene-acrylic copolymer is preferably 50°C to 90°C. By setting the temperature to 50°C or higher, it is possible to reduce the possibility that the contained parts will adhere to the heat seal of the cover tape under transportation conditions such as shipping. In addition, the mass average molecular weight was measured using the following GPC measuring device and conditions. Device name: High-speed GPC device HLC-8220 (manufactured by Tosoh Corporation) Column: PLgelMIXED-B3 tubes in series Temperature: 40°C Detection: Differential refractive index Solvent: Tetrahydrofuran Concentration: 2wt% Calibration curve: prepared using standard polystyrene (manufactured by Polymer Laboratories), and calculating the mass average molecular weight (Mw) as a molecular weight converted to polystyrene.

The heat sealing layer in this embodiment is insulating. By insulating, for example, the surface resistivity measured under the conditions of ambient temperature 23°C, ambient humidity 50%RH, and applied voltage 10V is 10 ¹¹ Ω according to JISK6911. /□ or above. It is preferably 10 ¹³ Ω/□ or more, more preferably 10 ¹⁴ Ω/□ or more. In a further embodiment of the present invention, the content of an additive that imparts conductivity (such as a conductive agent, etc.) in the heat sealing layer is preferably less than 0.01% by mass in the heat sealing layer, and more preferably does not contain a conductive agent.

The meaning of polyolefin resin refers to a resin composed of a polymer containing α-olefin as a monomer, including polyethylene resin and polypropylene resin. As polyethylene resin, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, linear medium-density polyethylene, etc. can be used. In addition, not only monomers but also copolymers, grafts, and mixtures having such structures can be used. Examples of the latter resin include ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-pentene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylate copolymers, ethylene-maleic acid copolymers, styrene-ethylene graft copolymers, styrene-propylene graft copolymers, styrene-ethylene-butadiene block copolymers, or copolymers and mixtures of resins having polar groups in the polyethylene chain further mixed with terpolymers of acid anhydrides, etc.

In addition, as the polypropylene resin, homopolypropylene, random polypropylene, block polypropylene, etc. can be used. When homopolypropylene is used, the structure of the homopolypropylene can be arbitrarily in the same row, in a mixed row, or in a opposite row. When using random polypropylene, as the α-olefin copolymerized with propylene, preferably one having 2 to 20 carbon atoms, more preferably one having 4 to 12 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene can be used. When using block polypropylene, block copolymers (block polypropylene), block copolymers containing rubber components, or graft copolymers can be used. In addition to using these olefin resins alone, other olefin resins can also be used in combination.

The average thickness of the heat sealing layer is less than 600nm, preferably 580nm or less, more preferably 400nm or less, still more preferably 250nm or less, still more preferably 200nm or less. The lower limit of the average thickness of the heat sealing layer is not particularly limited within the scope of implementation, and may be 5 nm or more, 10 nm or more, 20 nm or more, 30 nm or more, or 50 nm or more. A preferred range of the average thickness of the heat sealing layer is, for example: 5 nm or more and less than 600 nm, 10 nm or more and 580 nm or less, 20 nm or more and 400 nm or less, 30 nm or more and 250 nm or less, or 50 nm or more and 200 nm or less. By setting the average thickness of the heat sealing layer to a certain value or more, insulation properties can be obtained. By setting the average thickness of the heat sealing layer to less than 600 nm, the generation of electrostatic attraction can be suppressed. As will be described later, the heat sealing layer is usually formed by coating. However, when formed by a coating method, the thickness described here refers to the thickness after drying. The method for measuring the average thickness will be described later.

In addition, in the cover tape of one embodiment of the present invention, an inorganic filler is added to the heat seal layer. The cover tape of this embodiment is heat-sealed to the surface of the carrier tape containing the electronic components, and then baked at 60°C for 72 hours or at 80°C for about 24 hours to remove the moisture contained in the sealing resin. In this case, if the electronic components as the contents are adhered to the cover tape, problems will occur in the process of peeling off the cover tape and installing the electronic components. In the cover tape of the present embodiment, the deviation of the peeling strength when peeling off the cover tape is small, and the adhesion of the heat seal layer to the electronic parts of the content can still be controlled at a high temperature of 60 to 80°C, so the adhesion problem of such electronic parts can be solved to a considerable extent. However, if an inorganic filler is added to the heat seal layer, the effect of preventing adhesion can be achieved more reliably. Here, the added inorganic filler can be any material as long as it can significantly achieve the above-mentioned effect of preventing adhesion, but it is preferably other than materials that impart conductivity. For example, spherical or crushed talc particles, silica particles, aluminum oxide particles, mica particles, calcium carbonate, magnesium carbonate, etc. can be cited. In order to maintain the transparency of the cover tape, the inorganic filler has a median particle size (D50) of less than 400 nm and contains, for example, 10 to 30 mass %.

(Conductive layer) As shown in FIG1 , the conductive layer is a layer constituting the cover tape and is directly laminated on the heat seal layer. The conductive layer in the present embodiment has conductivity. The so-called "conductive" means, for example, that the surface resistivity measured under the conditions of an ambient temperature of 23°C, an ambient humidity of 50%RH, and an applied voltage of 10V according to JIS K6911 is 10 ¹⁰ Ω/□ or less. Preferably, it is 10 ⁹ Ω/□ or less, and more preferably, it is 10 ⁸ Ω/□ or less.

The average thickness of the conductive layer is preferably 0.005-100 μm, more preferably 0.01-1 μm, even more preferably 0.05-0.1 μm. By setting the thickness of the conductive layer to 0.005 μm or more, coating omissions during application of the conductive layer can be suppressed. On the other hand, by setting the thickness to 100 μm or less, costs can be suppressed. In addition, as will be described later, the conductive layer is usually formed by coating. However, when formed by a coating method, the thickness described here refers to the thickness after drying.

The conductive layer preferably contains a thermoplastic resin. The thermoplastic resin constituting the conductive layer is a resin containing olefins as components, for example, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-maleic acid copolymer, styrene-ethylene graft copolymer, styrene-propylene graft copolymer, styrene-ethylene-butadiene block copolymer, propylene, etc. These polyolefins can be used alone or in combination of two or more thereof.

In one embodiment of the present invention, the conductive layer contains a conductive agent. Examples of the conductive agent include conductive tin oxide particles, conductive zinc oxide particles, conductive titanium oxide particles, and the like. Among them, tin oxide doped with antimony, phosphorus or gallium exhibits high conductivity and reduced transparency loss, so it is more suitable for use. The conductive tin oxide particles, the conductive zinc oxide particles, and the conductive titanium oxide particles can be in the form of spheres, needles, or mixtures thereof. Particularly in the case of using antimony-doped acicular tin oxide, a cover tape with particularly good antistatic properties can be obtained. The amount of the conductive agent added is preferably 65 to 95 mass %, more preferably 67 to 93 mass %, and still more preferably 70 to 90 mass % with respect to the material constituting the conductive layer. By setting the addition amount of conductive fine particles to 65 mass % or more, the surface resistivity of the heat sealing layer side of the cover tape is suppressed from becoming 10 ¹⁰ Ω/□ or more; by setting it to 95 mass % or less, the surface resistivity of the thermoplastic resin is suppressed. The amount is relatively reduced, and the decrease in peel strength caused by the heat sealing layer is suppressed.

As the conductive agent, carbon nanomaterials such as carbon nanotubes and carbon nanofibers can be included. Among them, carbon nanotubes with an aspect ratio of 10 to 10,000 are preferred. The amount of carbon nanomaterial added is 1 to 50 mass%, preferably 5 to 45 mass%, relative to the material constituting the conductive layer. By setting the addition amount to 1 mass % or more, the effect of imparting conductivity by adding carbon nanomaterials can be obtained; by setting it to 50 mass % or less, an increase in cost and a decrease in the transparency of the cover tape can be suppressed. In addition, as the conductive agent, conductive polymers such as water-soluble polymer hydrogel, polythiophene-based conductive polymer, polyaniline-based conductive polymer, and polypyrrole-based conductive polymer may be included. The amount of the conductive polymer added is 1 to 50 mass %, preferably 5 to 45 mass %, based on the material constituting the conductive layer.

(Substrate layer) The base material layer preferably contains thermoplastic resin. As the thermoplastic resin constituting the base material layer, a resin containing at least one of polyester resin, polyolefin resin, and super engineering plastic can be used.

The polyester resin is a polyester resin having two or more active hydrogens such as hydroxyl groups and amine groups in the molecule. Specific examples thereof include polyester polyol, polyester polyamine, and the like. The polyester polyol preferably has a hydroxyl value (mgKOH/g) of 1 to 200 and a number average molecular weight of 1,000 to 50,000. In addition, the number average molecular weight described here is a value measured based on JISK7252. Examples of the polyester polyol include condensation reaction products of polyvalent hydroxyl-containing compounds and ester-forming derivatives such as polycarboxylic acids or acid anhydrides and lower alkyl (alkyl having 1 to 4 carbon atoms) esters thereof. More specific examples include: polyethylene terephthalate, polyethylene naphthalate, polyarylate, polyethylene 2,6-naphthalate, polyethylene terephthalate, and Examples of copolymer components include glycol components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol; adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalene dicarboxylic acid. Polyester resin made by copolymerization of dicarboxylic acid components such as formic acid, etc. The content of the polyester resin when combining the polyester resin with other resins is not particularly limited. For example, the content of the polyester resin in the thermoplastic resin may be 50 mass% or more, 70 mass% or more, or 90 mass% or more.

Examples of polyolefin-based resins include polyethylene-based resins and polypropylene-based resins. As the polyethylene-based resin, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, linear medium-density polyethylene, etc. can be used, and not only monomers but also those having structures such as these can be used. Copolymers, grafts, blends. Examples of the latter resin include those obtained by copolymerizing monomers having polar groups in the polyethylene chain, and those obtained by blending them. Examples of those obtained by copolymerizing monomers having polar groups in the polyethylene chain include: ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylate copolymer, ethylene-methyl Acrylate copolymers, ethylene-vinyl acetate-vinyl chloride copolymers, terpolymers of the aforementioned copolymers and acid anhydrides.

In addition, as polypropylene resins, homopolypropylene, random polypropylene, block polypropylene, etc. can be used. When homopolypropylene is used, the structure of the homopolypropylene can be any of the same row, mixed row or opposite row. When using random polypropylene, the α-olefin copolymerized with propylene is preferably one with 2 to 20 carbon atoms, and more preferably one with 4 to 12 carbon atoms, for example, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene can be used. When using block polypropylene, block copolymers (block polypropylene), block copolymers containing rubber components, or graft copolymers can be used. In addition to using these olefin resins alone, other olefin resins can also be used in combination. The content of the polyolefin resin when the polyolefin resin is combined with other resins is not particularly limited, and for example, the content of the polyolefin resin in the thermoplastic resin is 50% by mass or more, 70% by mass or more, or 90% by mass or more.

Examples of super engineering plastics include fluororesins such as polytetrafluoroethylene and polyvinylidene fluoride; polyphenylene sulfide, liquid crystal polymer, polyacrylate, thermoplastic polyimide, ketone resin, sulfonate resin, etc. When super engineering plastics are combined with other resins, the content of super engineering plastics is not particularly limited. For example, the content of super engineering plastics in the resin can be 50% by mass or more, 70% by mass or more, or 90% by mass or more.

The film used as the substrate layer may be unstretched, uniaxially stretched or biaxially stretched.

The average thickness of the substrate layer is preferably 5 to 50 μm, more preferably 8 to 30 μm. By setting the thickness of the substrate layer to 5 μm or more, the occurrence of "film rupture" when peeling off the cover tape due to the reduction in the tensile strength of the cover tape itself can be suppressed. On the other hand, by setting the thickness to 50 μm or less, the reduction in heat sealing properties to the carrier tape and the increase in cost can be suppressed. The method for measuring the average thickness is as described above.

(Cover Tape) The cover tape of this embodiment has a surface resistivity of 1×10 ¹⁰ Ω on the heat sealing layer side surface measured in accordance with JISK6911 under the conditions of an ambient temperature of 23° C., an ambient humidity of 50% RH, and a voltage of 10 V. /□ or less, preferably 1×10 ⁶ to 5×10 ⁹ Ω/□, more preferably 1×10 ⁶ to 2×10 ⁸ Ω/□. On the other hand, the lower limit value is not particularly limited within the feasible range, and may be 1×10 ⁴ Ω/□, 1×10 ⁵ Ω/□, or 1×10 ⁶ Ω/□. The preferable range of the surface resistivity of the side surface of the heat sealing layer can be, for example, 1×10 ⁴ Ω/□～1×10 ¹⁰ Ω/□, 1×10 ⁵ Ω/□～1×10 ⁹ Ω/□, or 1 ×10 ⁶ Ω/□～1×10 ⁸ Ω/□. The surface resistivity value of the cover tape of this embodiment is lower than the value measured for the surface resistivity of the heat sealing layer alone, but it is considered to be due to the influence of the directly laminated conductive layer. The surface resistivity of the heat sealing layer side of the cover tape can be adjusted by changing the content of the conductive agent in the heat sealing layer and the conductive layer, and the thickness of the heat sealing layer. In addition, in the cover tape according to one embodiment of the present invention, it is preferable that the layers other than the conductive layer are insulating, and it is more preferable that the content of the conductive additive (such as conductive agent, etc.) in this layer is less than 0.01 mass. %, and preferably does not contain conductive agent.

In one embodiment of the present invention, the average thickness of the cover tape is preferably 20 to 80 μm, and more preferably 40 to 60 μm. By setting the average thickness of the cover tape to be greater than 20 μm, cutting when peeling the cover tape can be prevented. On the other hand, by setting the average thickness of the cover tape to be less than 80 μm, not only can the cost increase be suppressed, but also the productivity can be improved by shortening the sealing time. The thickness of the layer is measured by cutting out a 20 mm square section from 5 points at equal intervals in the width direction of the cover tape, smoothing the end face so that the layer structure can be determined, and then using a laser microscope (made by KEYENCE: VK-8510). The average thickness of the cover tape refers to the average value of the thickness from the surface of one side of the cover tape to the surface of the other side. The average thickness of each layer of the cover tape is measured at 5 points, and the arithmetic mean is taken as the average thickness.

[Second embodiment] As shown in FIG. 2 , the cover tape of the second embodiment of the present invention has an intermediate layer between the base layer and the conductive layer. The cover tape 1 shown in FIG. 2 is provided with a heat seal layer 2, a conductive layer 3, an intermediate layer 5, and a base layer 4 in sequence. In the cover tape 1, the heat seal layer 2 constitutes one surface, and the base layer 4 constitutes the other surface.

(Middle layer) The middle layer preferably contains a thermoplastic resin. As the thermoplastic resin constituting the middle layer, linear low-density polyethylene (hereinafter referred to as LLDPE) which has flexibility, moderate rigidity, and excellent tear strength at room temperature is preferably used. In particular, by using a resin having a density in the range of 0.900 to 0.925 (×10 ³ kg/m ³ ), it is difficult for the middle layer of resin to protrude from the end of the cover tape due to heat and pressure during heat sealing. Therefore, not only is it difficult for the soldering iron to fall out and become dirty during heat sealing, but the middle layer softens during heat sealing of the cover tape to alleviate uneven contact with the heat sealing soldering iron, making it easy to obtain stable peeling strength.

LLDPE includes those polymerized using Zigler type catalysts and those polymerized using metallocene catalysts (hereinafter referred to as m-LLDPE). Since the molecular weight distribution of m-LLDPE is controlled to be very narrow, it has high tear strength and can be suitably used as the middle layer of the present invention.

The m-LLDPE mentioned above is a copolymer of an olefin having more than 3 carbon atoms, preferably a linear, branched, or aromatic substituted α-olefin having 3 to 18 carbon atoms, as a comonomer, and ethylene. Examples of linear monoolefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. Examples of branched monoolefins include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, and 2-ethyl-1-hexene. In addition, examples of aromatic substituted monoolefins include styrene. These comonomers can be copolymerized with ethylene alone or in combination of two or more. In the copolymerization, polyenes such as butadiene, isoprene, 1,3-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene can be copolymerized. Among them, 1-hexene and 1-octene are preferably used as copolymer monomers because of their high tensile strength and excellent cost.

The average thickness of the intermediate layer is preferably 5 to 60 μm, more preferably 10 to 50 μm, and most preferably 15 to 40 μm. By setting the thickness of the intermediate layer to 5 μm or more, damage to the cover tape when the heat-sealed cover tape is peeled off at high speed can be suppressed, and when the cover tape is heat-sealed to the carrier tape, it is easier to obtain the insufficiency of the hot iron. Even contact lightening effect. On the other hand, by setting the thickness to 60 μm or less, since the total thickness of the cover tape is thick, it can be suppressed that sufficient peel strength cannot be obtained when the cover tape is heat-sealed to the carrier tape. The method for measuring the average thickness is as described above.

In one embodiment of the invention, an anchor coating is provided between the base material layer and the intermediate layer. In other words, a base material layer, an anchor coating, an intermediate layer, a conductive layer, and a heat sealing layer are provided in this order. The adhesive used for the anchor coating can be: polyurethane adhesive, polyvinyl acetate adhesive, polyacrylate adhesive, reactive (meth)acrylic adhesive, cyanide adhesive Acrylate based adhesives, ethylene copolymer based adhesives composed of copolymers of ethylene and vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid and other monomers, polyester based adhesives, polyamide Adhesives, polyimide adhesives, amine resin adhesives composed of urea resin or melamine resin, phenolic resin adhesives, epoxy adhesives, chloroprene rubber, Rubber-based adhesives and other adhesives composed of styrene-butadiene rubber, etc. The composition system of the above-mentioned adhesive can be any composition form such as water-based type, solution type, emulsion type, dispersion type, etc., and its shape can be any form such as film/sheet, powder, solid, etc. In addition, the bonding mechanism can be any type such as chemical reaction type using a curing agent, solvent volatile type, hot melt type, hot pressing type, etc.

The average thickness of the anchor coating is usually in the range of 50 to 7000 nm, preferably in the range of 100 to 5000 nm. By setting the thickness of the peeling layer to 50 nm or more, coating omissions of the anchor coating layer are suppressed. On the other hand, by setting the thickness of the anchor coating layer to 7000 nm or less, the influence of the solvent remaining after drying is suppressed. The method for measuring the average thickness is as described above. The above-mentioned adhesive can be applied by, for example, roller coating, gravure roller coating, kiss coating, other coating methods, or printing methods. The ideal coating amount is 0.1 to 10 g/m ² (dry). condition).

[Other embodiments] In a cover tape according to another embodiment of the present invention, a peeling layer having a thermoplastic resin as a main component is provided between the intermediate layer and the conductive layer. Examples of the thermoplastic resin used for the release layer include acrylic resins, polyester resins, ethylene-vinyl acetate copolymer resins (hereinafter referred to as EVA), ethylene-acrylic acid copolymer resins, ethylene-methacrylic acid copolymer resins, styrene-isoprene diblock copolymer resins, styrene-isoprene diblock copolymer hydrogenated resins, styrene-butadiene diblock copolymer resins, styrene-butadiene diblock copolymer hydrogenated resins, styrene-isoprene-styrene triblock copolymer hydrogenated resins (hereinafter referred to as SEPS), styrene-butadiene-styrene triblock copolymer hydrogenated resins (hereinafter referred to as SEBS), styrene-butadiene random copolymer hydrogenated resins, styrene-isoprene random copolymer hydrogenated resins, and the like. Among them, considering the small deviation in peeling strength when peeling off the cover tape, it is better to use SEPS and SEBS with a styrene ratio of 15 to 35 mass%.

The average thickness of the release layer is usually in the range of 0.1 to 3 μm, preferably in the range of 0.1 to 1.5 μm. By setting the thickness of the release layer to 0.1 μm or more, it is possible to suppress insufficient peeling strength when heat-sealing the carrier tape to the cover tape. On the other hand, by setting the thickness of the release layer to 3 μm or less, it is possible to suppress the deviation in peeling strength when peeling the cover tape. In addition, as described later, the release layer is usually formed by coating, and when formed by coating, the thickness here refers to the thickness after drying. The method for measuring the average thickness is as described above.

[Manufacturing method of cover tape] The manufacturing method of the cover tape is not particularly limited, and a general method can be used. For example, an anchor coating agent is applied to the surface of the film-formed base layer if necessary, and the film-formed intermediate layer or the intermediate layer pressed from the T-mold is dry-laminated to form a base layer and an intermediate layer. laminated film. In addition, the resin composition constituting the conductive layer is coated on the conductive layer by, for example, a gravure coater, a reverse coater, a kiss coater, a knife coater, a wire bar coater, a dip coater, etc. A conductive layer is formed on the intermediate layer. In addition, the target cover tape can be obtained by coating the resin composition constituting the heat sealing layer on the conductive layer to form the heat sealing layer.

As another method, the conductive layer can be prepared in advance by a T-die casting method, an inflation method, or the like, and a resin composition constituting a heat-sealing layer can be coated thereon to obtain a film having a conductive layer and a heat-sealing layer.

[usage] Cover tape can be used as a cover material for holding containers for electronic components, that is, carrier tapes. The carrier tape is a strip with a width of approximately 8 mm to 100 mm and has a pocket for accommodating electronic components. When a cover tape is used as the cover material for heat sealing, the material constituting the carrier tape is not particularly limited, and commercially available products can be used. For example, thermoplastic resins such as polystyrene, polyester, polycarbonate, and polyvinyl chloride can be used. When an acrylic resin is used for the heat seal layer, it is most ideal to use it in combination with a carrier tape such as polystyrene or polycarbonate. Carrier tapes can be used that have conductivity imparted by mixing carbon black and carbon nanotubes into the resin, mixed with antistatic agents and conductive agents, or surface-coated with dispersed surfactant-type antistatic agents, polypyrrole, A coating liquid containing conductive materials such as polythiophene and an organic binder such as acrylic acid to impart antistatic properties.

An electronic component packaging body containing electronic components is, for example, after accommodating the electronic components in the electronic component storage portion of the carrier tape, a cover tape is used as a cover material, and the cover tape is continuously heat-sealed and packaged along both longitudinal edges, and Wound on a shaft. This form of packaging is used to store and transport electronic components. Packages containing electronic components, etc., are transported using carrier tape transport holes called sprocket holes provided on the longitudinal edges of the carrier tape. While transporting, the cover tape is intermittently peeled off and the parts are installed after confirmation. The presence, orientation and position of electronic components on the device are taken out at the same time and mounted on the substrate.

In addition, when peeling off the cover tape, if the peeling strength is too small, it will peel off from the carrier tape, and there is a risk that the contained parts will fall off; if it is too large, it will be difficult to peel off from the carrier tape, and the cover tape may break during peeling, so the temperature between 120 and 220 When heat-sealed at 0.15 N, it is preferable to have a peel strength of 0.15 N or more and less than 1.5 N, and more preferably 0.2 N or more and less than 0.8 N.

The present invention is described in detail below based on embodiments, but the present invention is not limited thereto.

Various raw materials used in Examples and the like are as follows. (Heat sealing layer) ・Resin: Acrylic resin Digital BR-106 (manufactured by Mitsubishi Chemical Co., Ltd.), mass average molecular weight 30,000, glass transition temperature 50°C, acid value 3.5 mgKOH/g ・Conductive agent: Antimony-doped tin dioxide (ATO) FSS-10M (manufactured by Ishihara Industrial Co., Ltd.), needle-shaped antimony-doped tin oxide, medium diameter (D50), average major diameter 2 μm, average short diameter 0.1 μm, MEK dispersion type (conductive layer) ・Resin: Styrene-ethylene-butadiene copolymer resin Tuftec H1272 (manufactured by Asahi Kasei Co., Ltd.) ・Conductive agent: Antimony-doped tin oxide (ATO) FSS-10M (manufactured by Ishihara Industrial Co., Ltd.), needle-shaped antimony-doped tin oxide, medium diameter (D50), average major diameter 2 μm, average short diameter 0.1 μm, MEK dispersion type (Substrate layer) ・Biaxially stretched polyethylene terephthalate film T6142 (manufactured by Toyobo Co., Ltd.) thickness 12 μm (anchor coating) ・Main ingredient: Polyurethane adhesive (polyether polyol) TM-319 (manufactured by Toyo Morton Co., Ltd.), ethyl acetate solution, solid content concentration 70% by mass ・Hardening agent: Polyisocyanate-based hardening agent (diphenylmethane diisocyanate) CAT-11B (manufactured by Toyo Morton Co., Ltd.), ethyl acetate solution, solid content concentration 60% by mass (middle layer) ・Polyethylene film TCS (manufactured by Mitsui Tohcello Co., Ltd.), thickness 30 μm

(Example 1) Anchor coating and hardener (thickness: 4000nm) were applied to a biaxially stretched polyethylene terephthalate film (thickness: 12μm) as a substrate layer, and a polyethylene film (thickness: 30μm) was dry-laminated as an intermediate layer. Then, an ATO dispersion was mixed with a styrene-ethylene-butadiene copolymer resin dissolved in toluene to make the ATO content 80% by mass, and the surface of the intermediate layer was coated with a wire rod coater and dried (800nm thickness) as a conductive layer. Then, on the surface of the conductive layer, an acrylic resin dissolved in MEK was coated with a wire rod coater and dried to a thickness of 50nm as a heat seal layer.

(Example 2) The same method as Example 1 was used except that the acrylic resin was applied by a wire rod coater and dried so that the thickness of the heat seal layer was 100 nm.

(Example 3) Except that the acrylic resin was applied by a wire rod coater and dried so that the thickness of the heat seal layer was 200 nm, it was prepared in the same manner as in Example 1.

(Example 4) It was produced in the same manner as in Example 1, except that the acrylic resin was coated with a wire bar coater and dried so that the thickness of the heat seal layer was 300 nm.

(Example 5) It was produced in the same manner as in Example 1, except that the acrylic resin was coated with a wire bar coater and dried so that the thickness of the heat seal layer was 400 nm.

(Example 6) A conductive layer was prepared in the same manner as in Example 3 except that the ATO dispersion liquid was blended into the styrene-ethylene-butadiene copolymer resin so that the ATO content was 90% by mass.

(Example 7) A conductive layer was prepared in the same manner as in Example 3, except that the ATO dispersion was blended into the styrene-ethylene-butadiene copolymer resin so that the ATO content was 70% by mass.

(Example 8) The same method as Example 1 was used except that the acrylic resin was applied by a wire rod coater and dried so that the thickness of the heat seal layer was 500 nm.

(Comparative example 1) A heat sealing layer was prepared in the same manner as in Example 3, except that the ATO dispersion liquid was blended into the acrylic resin dissolved in MEK so that the ATO content was 80% by mass.

(Comparative example 2) A heat sealing layer was prepared in the same manner as in Example 3 except that the ATO dispersion was blended into the styrene-ethylene-butadiene copolymer resin so that the ATO content was 60% by mass.

(Comparative Example 3) The same method as Example 1 was used except that the acrylic resin was applied by a wire rod coater and dried so that the thickness of the heat seal layer was 600 nm.

<Evaluation method> The cover tapes prepared in each embodiment and each comparative example were evaluated as follows. The results are shown in Table 1. (1) Surface resistivity of cover tape The surface resistivity of the heat-sealed layer side of the cover tape was evaluated using HirestaUP MCP-HT450 manufactured by Nitto Seiko Analytical Science Co., Ltd. in accordance with the JIS K6911 method at an ambient temperature of 23°C, an ambient humidity of 50% RH, and an applied voltage of 10V.

(2) Adhesion rate of parts to cover tape Under the conditions of ambient temperature of 23°C and ambient humidity of 50%RH, the cover tape, carrier tape, and 15 parts were packaged after removing static electricity with an ionizer. The heat seal layer of the cover tape and the parts were fixed in contact and vibrated for 10 minutes at a speed of 2000 rpm using CuteMixer (manufactured by Tokyo Rikkigi Co., Ltd.). When the cover tape was peeled off at a peeling speed of 600 mm/min and a peeling angle of 170 to 180 degrees, the number of parts attached to the cover tape was evaluated and the part adhesion rate was calculated. A conductive polystyrene carrier tape was used as the carrier tape. The following parts were used as parts. (Part 1) DFN package, width 0.8mm x depth 0.8mm x thickness 0.4mm, weight 0.6mg (Part 2) BGA package, width 1.0mm x depth 1.0mm x thickness 0.4mm, weight 1.5mg When the adhesion rate is less than 5%, it is "excellent"; when it is more than 5% and less than 15%, it is "good"; when it is more than 15%, it is rated as "unacceptable".

(3) Electrostatic voltage of parts Under the conditions of an ambient temperature of 23°C and an ambient humidity of 50%RH, the cover tape, carrier tape and 15 parts were packaged after removing static electricity using an ionizer. The heat seal layer of the cover tape was fixed to the parts and vibrated at a speed of 2000 rpm for 10 minutes using CuteMixer (manufactured by Tokyo Rikki Co., Ltd.). After the carrier tape was peeled off while the heat seal layer of the cover tape was in contact with the parts, the parts were clamped with ceramic tweezers that had been de-staticized, and the electrostatic voltage of the contact surface with the heat seal layer was measured. Using an electrostatic voltmeter (manufactured by MONROE ELECTRONICS), the average electrostatic voltage of the 15 parts was obtained. Conductive polystyrene carrier tape was used as the carrier tape. The following parts were used as the parts. (Part 1) DFN package with a width of 0.8 mm x a depth of 0.8 mm x a thickness of 0.4 mm and a weight of 0.6 mg (Part 2) BGA package with a width of 1.0 mm x a depth of 1.0 mm x a thickness of 0.4 mm and a weight of 1.5 mg

[Table 1]

The results shown in Table 1 reveal the following. In all the cover tapes of Examples 1 to 8, the adhesion rate of electronic components to the cover tape due to static electricity was less than 15%, and the adhesion to the cover tape was suppressed. It is speculated that this is because electrostatic attraction is generated inside the cover tape, which suppresses the electrostatic attraction from the surface of the heat seal layer to the outside. On the other hand, the adhesion rate of the cover tapes of Comparative Examples 1 and 2 is at least as high as 25%, which is difficult to be fully suppressed. In particular, the cover tape of Comparative Example 1 contains a conductive agent in the heat seal layer, so induced charging is generated in the heat seal layer. It is speculated that electrostatic attraction is generated due to the generation of charge. In addition, in the cover tape of Example 2, since the content of the conductive agent in the conductive layer is low, the induction charging in the conductive layer is difficult to occur, and it is estimated that the electrostatic attraction of the self-heat-sealing layer surface to the outside cannot be suppressed. The adhesion rate of the cover tape of Example 3 is as high as 20% in the case of part 1, and it is difficult to say that the adhesion is fully suppressed.

The present invention has been described above using various embodiments, but the technical scope of the present invention is certainly not limited to the scope described in the above embodiments. It is obvious that a person with ordinary knowledge in the relevant field can add various changes or improvements to the above embodiments. In addition, it can be seen from the description of the patent application scope that the various changes or improvements added are also included in the technical scope of the present invention.

The cover tape of this embodiment can suppress the generation of electrostatic attraction between the heat seal layer and the electronic components, and can provide a cover tape with a low risk of the electronic components adhering to the cover tape when the cover tape is peeled off to remove the electronic components, and has industrial applicability.

1: Cover tape 2: Heat seal layer 3: Conductive layer 4: Base material layer 5: Intermediate layer

FIG1 is a cross-sectional view showing the layer structure of the cover tape of the first embodiment of the present invention. FIG2 is a cross-sectional view showing the layer structure of the cover tape of the second embodiment of the present invention.

1: Cover tape

2: Heat sealing layer

3: Conductive layer

4: Base material layer

Claims (10)

A cover tape having: an insulating heat sealing layer provided on one surface, and a conductive layer directly laminated on the heat sealing layer, with the surface resistivity of the heat sealing layer side being 1×10 ¹⁰ Ω/□ or less; Thermal The average thickness of the sealing layer is less than 600nm. The cover tape of claim 1, wherein the conductive layer contains resin and a conductive agent. The cover tape of claim 2, wherein the conductive agent is selected from the group consisting of conductive tin oxide particles, conductive polymers and carbon nanomaterials. In the cover tape of claim 2 or 3, the conductive layer contains 65-95 mass % of a conductive agent, and the conductive agent is conductive tin oxide particles. The cover tape of claim 4, wherein the conductive tin oxide particles are antimony-doped tin dioxide (ATO). The cover tape of claim 1 or 2 comprises a heat sealing layer, a conductive layer, and a substrate layer in sequence. For example, the cover tape of claim 1 or 2 has a heat sealing layer, a conductive layer, an intermediate layer, and a base material layer in order. The cover tape of claim 1 or 2, wherein the thickness of the heat seal layer is 30 to 250 nm. The cover tape of claim 1 or 2 is used as a cover material for an electronic component package. An electronic parts packaging body, which includes: a carrier tape and a cover tape according to claim 1 or 2.

Images