Cover tape and electronic component package including the same

Abstract

To provide a cover tape which is unlikely to absorb moisture even under high temperature and low humidity, and has good visibility, and an electronic component package including the same.SOLUTION: A cover tape has transmittance at a wavelength of 1,300 to 1,500 nm of 75% or more, and a haze value of less than 30%. Preferably, the cover tape has transmittance at a wavelength of 1,200 to 1,600 nm of 75% or more. Preferably, an increase / decrease rate of transmittance (T2) at a wavelength of 1,600 nm to transmittance (T1) at a wavelength of 1,200 nm, which is represented by the following expression (1), is 90% or more. Expression (1): (T2 / T1)×100(%).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a cover tape and an electronic component package including the same. [Background technology]

[0002] As electronic devices become smaller, the electronic components used are also becoming smaller and more powerful. At the same time, electronic components are being automatically mounted on printed circuit boards during the assembly process of electronic devices. These chip-type surface-mount electronic components are housed in a carrier tape with a series of thermoformed storage pockets formed to fit the shape of the electronic components. After the electronic components are housed in each storage pocket, a cover tape is placed on top of the carrier tape as a lid, and both ends of the cover tape are heat-sealed continuously in the longitudinal direction with a heated sealing iron to form a package for the electronic components.

[0003] However, cover tapes may be exposed to high-temperature and high-humidity environments during transportation and storage, which can cause the cover tape to absorb moisture. If the moisture absorption rate of the cover tape becomes too high, problems such as blocking may occur in the rolled cover tape and reduced heat-sealing properties may occur. Furthermore, if the cover tape absorbs moisture after being used as an electronic component package, there is a concern that this may affect the electronic components contained therein.

[0004] To address this issue, for example, Patent Document 1 proposes a cover tape that is less likely to cause blocking even when exposed to high temperature or high temperature and humidity environments. On the other hand, no study has been conducted on a cover tape that is less likely to absorb moisture even under high temperature and high humidity conditions.

[0005] Furthermore, the cover tape used in the electronic component package is required to have sufficient visibility to allow the enclosed electronic components to be visually observed from the cover tape side. However, no cover tape that is resistant to moisture absorption even under high temperature and high humidity conditions and also has good visibility is known. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2013 / 054867 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a cover tape that is resistant to moisture absorption even under high temperature and high humidity conditions and has good visibility, and an electronic component package including the same. [Means for solving the problem]

[0008] As a result of extensive research into the above-mentioned problems, the present inventors have surprisingly found that there is a correlation between the transmittance of a cover tape in the near-infrared wavelength range and the moisture absorption rate of the cover tape under high temperature and high humidity conditions, and that a cover tape with high transmittance and a low haze value can solve all of the above-mentioned problems. Specifically, they have found that a cover tape with a transmittance of 75% or more in the wavelength range of 1300 to 1500 nm and a haze value of less than 30% is less likely to absorb moisture even under high temperature and high humidity conditions and also has good visibility. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a cover tape that is resistant to moisture absorption even under high temperature and high humidity conditions and has good visibility, and an electronic component package including the same. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a graph showing transmittance measurement results for cover tapes of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present disclosure will be described in detail below. However, the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. Furthermore, when multiple upper and lower limits are described for a particular parameter, any of these upper and lower limits can be combined to form a suitable numerical range. Furthermore, the lower and / or upper limits of a numerical range described in this disclosure are numerical values ​​within that range and may be replaced with numerical values ​​shown in the examples. The expression "X to Y" indicating a numerical range means "X or more and Y or less." If a specific description described for one embodiment also applies to other embodiments, that description may be omitted in other embodiments.

[0012] The configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited to the embodiments. Each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

[0013] [Cover tape] A first embodiment of the present disclosure relates to a cover tape. The cover tape according to the first embodiment has a transmittance of 75% or more in the wavelength range of 1300 to 1500 nm and a haze value of less than 30%. Light with a wavelength of 1300 to 1500 nm is in the near-infrared wavelength range. Thus, a cover tape with a transmittance of 75% or more in the near-infrared wavelength range and a haze value of less than 30% is less likely to absorb moisture even under high temperature and high humidity conditions. It also has good visibility.

[0014] In this disclosure, "transmittance of 75% or more at wavelengths of 1300 to 1500 nm" means that the transmittance of the cover tape is 75% or more at any wavelength within that wavelength range, which is different from an average transmittance of 75% or more in that wavelength range. In addition, in this disclosure, "good visibility" includes the ability to confirm the orientation of the enclosed electronic components and the letters and serial numbers printed on the surface of the electronic components from the cover tape side using a digital microscope or the like when the cover tape is used as an electronic component packaging body.

[0015] <Transmittance> The transmittance of the cover tape according to the first embodiment can be measured by the following method. (Transmittance measurement method) The measurement and analysis equipment used is an ultraviolet-visible-near-infrared spectrophotometer (e.g., Shimadzu Corporation, product name "UV-3600") and a multipurpose large sample chamber (φ60 mm, with built-in integrating sphere; e.g., Shimadzu Corporation, product name "MPC-3100"). First, baseline correction is performed without cover tape, then cover tape is attached and the spectral transmittance is measured using the integrating sphere at wavelengths of 1200 to 1600 nm.

[0016] In one embodiment, from the viewpoint of easily obtaining a cover tape that is less likely to absorb moisture under high temperature and high humidity, the transmittance at a wavelength of 1300 to 1500 nm may be 77% or more, 78% or more, 79% or more, or even 80% or more. In one embodiment, the transmittance in this wavelength range may be 90% or more. Note that, from the viewpoint of obtaining a cover tape that is less likely to absorb moisture under high temperature and high humidity, the upper limit of the transmittance in this wavelength range is not particularly limited.

[0017] The cover tape according to the first embodiment preferably has a transmittance of 75% or more in the wavelength range of 1200 to 1600 nm. Studies by the present inventors have revealed that a cover tape having a transmittance of 75% or more in a wavelength range wider than the wavelength range of 1300 to 1500 nm is less likely to absorb moisture under high temperature and high humidity conditions. In the present disclosure, "a transmittance of 75% or more in the wavelength range of 1200 to 1600 nm" means that the cover tape has a transmittance of 75% or more at any wavelength within that wavelength range, which is different from an average transmittance of 75% or more within that wavelength range.

[0018] In one embodiment, the transmittance at wavelengths of 1200 to 1600 nm may be more than 75%, or may be 76% or more. In one embodiment, the transmittance at wavelengths of 1200 to 1600 nm may be 80% or more, 85% or more, or 87% or more. From the viewpoint of obtaining a cover tape that is less likely to absorb moisture under high temperature and high humidity conditions, the upper limit is not particularly limited.

[0019] In one embodiment, the change rate of the transmittance (T2) at a wavelength of 1600 nm relative to the transmittance (T1) at a wavelength of 1200 nm of the cover tape, as represented by the following formula (1), may be 90% or more. (T2 / T1) × 100(%) (1)

[0020] If the rate of change expressed by the formula (1) is 90% or more, the cover tape is likely to be less hygroscopic under high temperature and high humidity conditions. For example, when the transmittance (T2) at a wavelength of 1600 nm is 75%, a cover tape having a transmittance (T1) at a wavelength of 1200 nm of 83.3% or more is preferred as a cover tape that satisfies the formula (1). Furthermore, the cover tape having a transmittance of 75% or more at wavelengths of 1200 to 1600 nm is preferred because it is likely to have a rate of change expressed by the formula (1) of 90% or more.

[0021] The upper limit of the increase / decrease rate represented by the above formula (1) is not particularly limited as long as the effects of the present invention are achieved. Since the cover tape according to the first embodiment may include a mode where T1 < T2, the increase / decrease rate may be 100% or more. In one embodiment, the increase / decrease rate may be 90 to 105%, may be 90 to 102%, or may be 95 to 102%.

[0022] <Haze value> The haze value of the cover tape according to the first embodiment is less than 30%. By having the above-mentioned transmittance and a haze value less than 30%, a cover tape with good visibility and low moisture absorption even under high temperature and high humidity conditions can be obtained. The haze value of the cover tape can be measured by the following method. (Method for measuring haze value) In accordance with JIS K7361-1:1997, measure the haze value of the cover tape using a haze meter (for example, manufactured by Nippon Denshoku Industries Co., Ltd., product name "Haze Meter NDH 7000").

[0023] From the viewpoint that the visibility of the cover tape is more likely to be better, the haze value is preferably 28% or less, more preferably 26% or less, and even more preferably 25% or less.

[0024] Typical cover tapes, such as cover tape 7 shown in Comparative Example 1 below, tend to have a gradually decreasing transmittance as the wavelength shifts toward higher near-infrared wavelengths. In the case of cover tape 7 shown in Comparative Example 1, the transmittance at 1300 nm and 1400 nm is 75% or higher, but the transmittance at 1500 nm is less than 75%. Furthermore, the aforementioned increase / decrease rate for such cover tapes is less than 90%. The present inventors conducted research into cover tapes that are less likely to absorb moisture under high temperatures and high humidity and found a correlation between the transmittance in the near-infrared wavelength range and the moisture absorption rate under high temperatures and high humidity. That is, the present inventors found that cover tapes such as those in Comparative Example 1 are prone to moisture absorption under high temperatures and high humidity. Therefore, they investigated cover tapes with increased transmittance in the near-infrared wavelength range that are less likely to absorb moisture under high temperatures and high humidity and found that designing such high transmittance increases the haze value, which tends to reduce visibility. In other words, to create a cover tape that is resistant to moisture absorption even under high temperature and high humidity conditions and also has good visibility, it is necessary to increase the transmittance in the near-infrared wavelength range and reduce the haze value.However, as shown in Comparative Example 3, there is a trade-off between the transmittance and the haze value, so it is very difficult to achieve both. After extensive research, the inventors of the present application succeeded in developing a cover tape with a transmittance of 75% or more in the near-infrared wavelength range and a haze value of less than 30% by selecting the resin components constituting the cover tape (preferably by designing the resin components of the cover tape so that they do not contain polyamide-based resins) and by laminating each layer so that the layer surfaces are smooth (preferably by laminating so that the surface of the intermediate layer that contacts the heat seal layer is smooth). Such a cover tape is resistant to moisture absorption even under high temperature and high humidity conditions, making it less susceptible to problems caused by moisture absorption. Furthermore, it also provides good visibility when used in packaging for electronic components. In this disclosure, "polyamide-based resin" refers to a polyamide resin containing an aliphatic skeleton, commonly known as Nylon (registered trademark).

[0025] <Layer configuration> The cover tape according to the first embodiment can have a multi-layer structure in which a base layer, an intermediate layer, and a heat seal layer are laminated in this order. For each layer constituting the cover tape according to the first embodiment, it is preferable to select a thermoplastic resin, additives, etc. so that the transmittance of the cover tape at a wavelength of 1300 to 1500 nm is 75% or more. Furthermore, it is preferable to laminate each layer so that the layer surface is smooth. In a preferred embodiment, from the viewpoint of easily achieving the above transmittance, each layer constituting the cover tape does not contain a polyamide-based resin.

[0026] Below, we describe an example of a cover tape that has at least a base layer, an intermediate layer, and a heat seal layer and that is likely to achieve the transmittance requirements of the cover tape of the first embodiment, but the configuration of the cover tape of the first embodiment is not limited to the following.

[0027] <Base material layer> The substrate layer is a layer containing a thermoplastic resin, and is preferably made of a film formed from a thermoplastic resin. The thermoplastic resin constituting the substrate layer is preferably selected from the viewpoints of easily achieving a transmittance of 75% or more at a wavelength of 1300 to 1500 nm and satisfying the mechanical properties required of the cover tape. In one embodiment, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, polyolefin-based resins such as polypropylene, polycarbonate-based resins, etc. are preferred. Furthermore, it is more preferred that the substrate layer be composed of a biaxially stretched film.

[0028] The substrate layer preferably does not contain a polyamide resin, and is more preferably made of a polyester resin film such as a biaxially oriented polyethylene terephthalate film or a biaxially oriented polyethylene naphthalate film.

[0029] The thickness of the base layer is generally set arbitrarily within the range of 5 to 50 μm, taking into consideration the mechanical properties of the cover tape, etc. In the cover tape according to the first embodiment, the thickness of the base layer is preferably set so that the transmittance in the near-infrared wavelength range is 75% or more. From these viewpoints, the thickness of the base layer is preferably 10 to 30 μm, more preferably more than 10 μm but not more than 30 μm, and even more preferably 12 to 20 μm.

[0030] In one embodiment, at least one surface of the substrate layer may be surface-treated. Examples of the surface treatment include sandblasting, corona discharge treatment, and plasma treatment. In one embodiment, the surface of the substrate layer on which the intermediate layer is laminated is preferably surface-treated. By surface-treating the substrate layer, the adhesive strength between the substrate layer and the intermediate layer is likely to be improved.

[0031] <Middle class> The intermediate layer is a layer of a thermoplastic resin laminated on one side of the substrate layer, if necessary via an adhesive layer or an anchor coat layer. The present inventors have found that the transmittance of a cover tape in the near-infrared wavelength range is easily affected by the thermoplastic resin that constitutes the intermediate layer. As a result of further investigation, the present inventors have found that when the intermediate layer does not contain a polyamide-based resin, the transmittance in the wavelength range of 1300 to 1500 nm is likely to be 75% or more. Furthermore, from the viewpoint of also easily achieving a transmittance in the wavelength range of 1200 to 1600 nm of 75% or more, they have also found that it is preferable for the intermediate layer to contain no polyamide-based resin but to contain a polyolefin-based resin.

[0032] Examples of polyolefin resins that can be used include polyethylene (e.g., low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and very low-density polyethylene (VLDPE)), ethylene-propylene copolymers, ethylene-1-butene copolymers, ethylene-1-pentene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid ester copolymers, ethylene-maleic acid copolymers, styrene-ethylene graft copolymers, styrene-propylene graft copolymers, styrene-ethylene-butadiene block copolymers, and polypropylene. These polyolefin resins may be used alone or as a mixture of two or more. The intermediate layer may also be two or more layers made of different polyolefin resins, such as a layer made of polyethylene and a layer made of ethylene-1-butene copolymer.

[0033] From the viewpoint of easily obtaining a cover tape that has a transmittance of 75% or more at wavelengths of 1300 to 1500 nm and is less likely to absorb moisture under high temperature and high humidity conditions, it is preferable that the intermediate layer contains only a polyolefin resin as the resin component, and it is more preferable that it contains only LLDPE.

[0034] The intermediate layer may be composed of one layer (single layer structure), or may have a multilayer structure in which two or more layers are laminated. In the case of a multilayer structure, from the viewpoint of transmittance and the tendency for the haze value to be low, it is preferable to have a structure in which two or more layers of the same type of polyolefin resin are laminated. Here, "the same type of polyolefin resin" means that the olefin units contained in the polyolefin resin are the same, but the molecular weights, etc., may be different. In the case of a multilayer structure, the intermediate layer may be laminated directly on the substrate layer without an anchor coat layer therebetween.

[0035] When the intermediate layer contains LLDPE, linear low-density polyethylene (m-LLDPE) polymerized with a metallocene catalyst is preferred.

[0036] The m-LLDPE is a copolymer of ethylene and an olefin having 3 or more carbon atoms, preferably a linear, branched, or aromatic nucleus-substituted α-olefin having 3 to 18 carbon atoms, as a comonomer. 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. Examples of aromatic nucleus-substituted monoolefins include styrene. These comonomers can be copolymerized with ethylene either alone or in combination. In this copolymerization, polyenes such as butadiene, isoprene, 1,3-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene may be copolymerized.

[0037] In the cover tape, the thickness of the intermediate layer is generally 5 to 50 μm, and preferably 10 to 40 μm. The thickness of the intermediate layer is generally set from the viewpoint of various physical properties such as the adhesive strength between the intermediate layer and the base layer and the peel strength during heat sealing. In the cover tape according to the first embodiment, it is preferable to control the thickness of the intermediate layer from the viewpoint of providing a cover tape that has low moisture absorption under high temperature and high humidity conditions and has good visibility. In one embodiment, the thickness of the intermediate layer is preferably 10 to 40 μm, and more preferably 13 to 38 μm. Alternatively, the thickness of the intermediate layer may be 20 to 38 μm.

[0038] In a preferred embodiment, the intermediate layer and the heat seal layer are laminated so that the surface of the intermediate layer that comes into contact with the heat seal layer is smooth.

[0039] <Heat seal layer> The heat seal layer is selected from the viewpoint of containing a thermoplastic resin that has heat sealability to the carrier tape and exhibits easy peelability, allowing for easy peeling during use. In this embodiment, it is also preferable to select a material that is likely to have a transmittance of 75% or more at wavelengths of 1300 to 1500 nm and a low haze value. From these viewpoints, preferred thermoplastic resins contained in the heat seal layer include ethylene-based resins such as polyethylene (e.g., LDPE, LLDPE, VLDPE, etc., as exemplified for the intermediate layer above), ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butene-1 random copolymer; and styrene-based resins such as styrene-butadiene copolymer (SB), styrene-butadiene-styrene block copolymer (SBS) or its hydrogenated product (SEBS), polystyrene (PS), styrene-butadiene copolymer (SBC), and high impact polystyrene (HIPS). These thermoplastic resins may be used alone or in combination of two or more.

[0040] In a preferred embodiment, from the viewpoint of making it easier to obtain a cover tape having a transmittance of 75% or more at wavelengths of 1200 to 1600 nm, it is more preferable that the heat seal layer contains at least one styrene-based resin selected from SB, SEBS, and SBC as a main component, or contains only an olefin-based resin.

[0041] The thickness of the heat seal layer is generally set from the viewpoint of heat sealing properties with the carrier tape. In the cover tape according to the first embodiment, it is preferable to control the thickness of the heat seal layer from the viewpoint of easily controlling the transmittance at wavelengths of 1300 to 1500 nm to 75% or more and easily obtaining a cover tape with a haze value of less than 30%. In one embodiment, the thickness of the heat seal layer is preferably less than 20 μm, preferably 3 μm or more and less than 20 μm, and more preferably 5 to 15 μm.

[0042] In one embodiment, the heat seal layer may contain one or more antistatic agents, which will be described later. When the heat seal layer contains an antistatic agent, the heat seal layer has both heat sealability and antistatic properties.

[0043] (adhesive layer or anchor coat layer) In one embodiment, an adhesive layer or anchor coat layer can be provided between the intermediate layer and the base layer, or between the intermediate layer and the heat seal layer. When providing an adhesive layer or anchor coat layer, anchor coating agents such as polyurethane adhesives, polyethyleneimine, modified polybutadiene, and organic titanate compounds, and hot melt adhesives such as polyolefin resins, ethylene-vinyl acetate resins, ethylene-acrylic ester resins, and vinyl chloride-vinyl acetate resins can be used. Among these, from the viewpoint of providing a cover tape that is less likely to absorb moisture under high temperature and high humidity conditions and has good visibility, it is preferable that the anchor coat layer contain a polyurethane adhesive.

[0044] In one embodiment, it is preferable to provide an anchor coat layer between the intermediate layer and the base layer. When the intermediate layer is laminated via an anchor coat layer, the polyolefin resin constituting the intermediate layer is preferably a single layer, and more preferably, the intermediate layer is configured as a base layer / anchor coat layer / polyolefin resin such as LLDPE. With such a configuration, the aforementioned transmittance is likely to be 75% or more, and the cover tape is likely to have low moisture absorption under high temperature and high humidity conditions. In addition, the haze value is likely to be less than 30%.

[0045] (antistatic layer) The cover tape according to the first embodiment may further include an antistatic layer. The antistatic layer may be provided on the heat seal layer and / or on the surface of the base layer that is not in contact with the intermediate layer. The inclusion of the antistatic layer provides the cover tape with an antistatic effect, making it easier to prevent static breakdown of electronic components. As mentioned above, if the heat seal layer contains an antistatic agent, it is not necessary to provide an antistatic layer on the heat seal layer.

[0046] The antistatic layer is a layer containing an antistatic agent. The antistatic agent is selected from the viewpoint of easily achieving the surface resistivity required for the cover tape and easily achieving the aforementioned transmittance. In one embodiment, the antistatic agent may be selected from conductive fine particles such as barium sulfate, tin oxide, zinc oxide, indium oxide, titanium oxide, aluminum oxide, and antimony-doped tin oxide (ATO); ionic liquids containing cyclic quaternary nitrogen-containing cations; cationic surfactants such as quaternary ammonium salts; polyalkylene oxides (e.g., polyethylene glycol, polypropylene glycol, polybutylene glycol, ethylene oxide-propylene oxide copolymer, etc.), polyether esters having a polyoxyalkylene structure and an ester bond, and the like.

[0047] As the ionic liquid containing a cyclic quaternary nitrogen-containing cation (hereinafter simply referred to as "ionic liquid"), from the viewpoint of easily achieving the above-mentioned transmittance and easily imparting the desired antistatic properties, for example, 1,3-dimethylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-dimethylimidazolium phosphate, 1,3-dimethylimidazolium hydrozine sulfate, etc. can be used.

[0048] As the quaternary ammonium salt, from the viewpoint of easily achieving the aforementioned transmittance and easily imparting the desired antistatic properties, for example, trimethyl lauryl ammonium methyl sulfate, ethyl dimethyl stearyl ammonium ethyl sulfate, ethyl dimethyl oleyl ammonium ethyl sulfate, ethyl dimethyl lauryl ammonium ethyl sulfate, ethyl dimethyl stearyl ammonium metasulfonium, ethyl dimethyl lauryl ammonium metasulfonium, etc. can be used.

[0049] The antistatic layer may further contain the antistatic agent and a binder resin. Examples of binder resins include polyurethane resins, acrylic resins, polyvinyl chloride resins, ethylene-vinyl acetate resins, polyester resins, butadiene resins, styrene resins including hydrogenated resins, and acrylic-modified polyester resins, which may be used singly or in combination. From the viewpoint of easily controlling the transmittance at wavelengths of 1300 to 1500 nm to 75% or more, it is preferable that the binder resin does not contain a polyamide resin.

[0050] When the cover tape according to the first embodiment has an antistatic layer, it is preferable that the cover tape contains at least one selected from an ionic liquid, ATO, and alumina oxide, from the viewpoint that the transmittance at wavelengths of 1300 to 1500 nm is likely to be 75% or more and that the transmittance at wavelengths of 1200 to 1600 nm is likely to be 75% or more. When the above-mentioned preferable antistatic agent is blended, the proportion of the antistatic agent is preferably 90% by mass or less based on the total mass of the resin composition constituting the antistatic layer.

[0051] The thickness of the antistatic layer is preferably 0.01 to 2.0 μm, from the viewpoint of easily achieving both antistatic properties and the above-mentioned transmittance.

[0052] (Total thickness of cover tape) The total thickness of the cover tape according to the first embodiment is preferably 40 to 65 μm, from the viewpoints of transmittance and haze, which facilitates achieving the various physical properties required of the cover tape. Furthermore, from the viewpoint of easily obtaining a cover tape with a 90 to 100% increase / decrease rate, the total thickness of the cover tape may be 40 to 50 μm, 42 μm or more but less than 50 μm, or 45 μm or more but less than 50 μm.

[0053] <Cover tape manufacturing method> The cover tape according to the first embodiment can be manufactured by laminating the aforementioned layers so that the transmittance at wavelengths of 1300 to 1500 nm is 75% or more and the haze value is less than 30%. Hereinafter, one embodiment of a method for manufacturing a cover tape comprising at least a base layer, an intermediate layer, and a heat seal layer as the cover tape according to the first embodiment will be described.

[0054] The manufacturing method according to this embodiment includes laminating a base layer, an intermediate layer, and a heat-sealing layer to achieve a transmittance of 75% or more at wavelengths of 1300 to 1500 nm and a haze value of less than 30%. In this case, from the viewpoint of easily achieving the transmittance of 75% or more, it is preferable to include selecting the thermoplastic resins for each layer so that the thermoplastic resins constituting the base layer, intermediate layer, and heat-sealing layer do not contain polyamide-based resins (step (1)). Furthermore, from the viewpoint of more easily controlling the transmittance to 75% or more, it is preferable to select the thermoplastic resins for each layer so that the intermediate layer contains an olefin-based resin. Furthermore, from the viewpoint of easily achieving a haze value of less than 30%, it is preferable to laminate the layers so that the layer surfaces are smooth, and it is more preferable to laminate so that the surface of the intermediate layer that contacts the heat-sealing layer is smooth.

[0055] In one embodiment, after the step (1), the process may include forming a heat seal layer (step (2)), applying a thermoplastic resin composition constituting an intermediate layer (hereinafter referred to as "resin composition for intermediate layer") to the base layer (step (3)), and laminating the base layer, intermediate layer, and heat seal layer (step (4)).

[0056] (Process (2)) The heat seal layer can be formed by, for example, a T-die casting method, an inflation method, etc. When an antistatic agent is blended into the heat seal layer, a resin composition containing the antistatic agent may be preblended in advance using a tumbler, and the resin composition may be formed into a film.

[0057] (Step (3)) Examples of coating the intermediate layer resin composition on the substrate layer include extruding the intermediate layer resin composition (preferably a polyolefin resin, particularly preferably containing LLDPE) through a T-die onto the surface of the substrate layer (preferably a biaxially oriented polyester film). Before coating the intermediate layer resin composition, an anchor coating agent (preferably a polyurethane adhesive) may be applied to the surface of the substrate layer, if necessary, and the intermediate layer may be laminated on the surface coated with the anchor coating agent. By extrusion-coating the molten resin composition for the intermediate layer onto the surface of the base layer and laminating the intermediate layer on the base layer, the surface of the intermediate layer that comes into contact with the heat seal layer tends to become smooth, making it easier to control the haze value to less than 30%.

[0058] (Step (4)) When laminating the base layer, intermediate layer, and heat seal layer, it is preferable to sandwich laminate the heat seal layer formed in step (3) on the intermediate layer obtained in step (3).

[0059] (Step (5)) In a preferred embodiment, the method further includes laminating an antistatic layer on the heat seal layer (step (5)). In laminating the antistatic layer on the heat seal layer, it is preferable to apply the resin composition constituting the antistatic layer using, for example, a gravure coater, a reverse coater, a kiss coater, an air knife coater, a Mayer bar coater, a dip coater, or the like.

[0060] In one embodiment, the manufacturing method may include, after the step (1), forming a two-layer film consisting of an intermediate layer and a heat-sealing layer (step (6)), and laminating the two-layer film and the base layer (step (7)).

[0061] (Process (6)) To produce a two-layer film consisting of an intermediate layer and a heat-sealing layer, the aforementioned resin composition for the intermediate layer (preferably a polyolefin resin, particularly preferably LLDPE) and the resin composition for the heat-sealing layer (hereinafter referred to as the "resin composition for the heat-sealing layer") are preferably extruded from separate single-screw extruders and laminated using a multi-manifold die. By laminating the intermediate layer and the heat-sealing layer into a two-layer film in this way, the surface of the intermediate layer that comes into contact with the heat-sealing layer tends to be smooth, making it easier to control the haze value to less than 30%.

[0062] (Process (7)) To laminate the two-layer film and the base layer, it is preferable to apply an anchor coating agent (preferably a polyurethane adhesive) to the surface of the base layer (preferably a biaxially oriented polyester film) as needed, and then laminate the two-layer film onto the side coated with the anchor coating agent by a dry lamination method.

[0063] (Process (8)) After step (7), step (8) may further comprise laminating an antistatic layer on the surface of the heat seal layer. Step (8) may be performed by the same method as step (5) described above.

[0064] In one embodiment, the manufacturing method may include, after step (1), forming a two-layer film consisting of a part of the intermediate layer and a heat seal layer (step (9)), coating the base layer with a resin composition that constitutes a part of the intermediate layer (step (10)), and laminating them so that the surface of the two-layer film facing the intermediate layer is in contact with the surface of the base layer facing the intermediate layer (step (11)).

[0065] (Process (9)) To produce a two-layer film consisting of a part of the intermediate layer and a heat-sealing layer, it is preferable to extrude the resin composition (preferably a polyolefin resin, particularly preferably containing LLDPE) that constitutes a part of the intermediate layer and the resin composition for the heat-sealing layer from separate single-screw extruders and laminate them using a multi-manifold die.

[0066] (Step (10)) The resin composition constituting a part of the intermediate layer is preferably applied to the substrate layer by extruding the resin composition constituting a part of the intermediate layer (preferably a polyolefin resin, particularly preferably LLDPE) from a T-die onto the surface of the substrate layer (preferably a biaxially oriented polyester film). Before applying the resin composition, an anchor coating agent (preferably a polyurethane adhesive) may be applied to the surface of the substrate layer, if necessary, and the intermediate layer may be laminated on the surface coated with the anchor coating agent. By combining steps (9) and (10), the surface of the intermediate layer that comes into contact with the heat seal layer tends to be smooth, and the haze value can be easily controlled to less than 30%.

[0067] (Step (11)) After step (10), the two-layer film and the substrate layer are laminated together so that the surface of the intermediate layer of the two-layer film contacts the surface of the intermediate layer of the substrate layer (sand lamination). Step (12) may also be included in which an antistatic agent is laminated on the heat seal layer. Step (11) may be the same method as step (5).

[0068] The intermediate layer of the cover tape obtained by the above steps (9) to (11) (or steps (9) to (12)) has a two-layer structure consisting of a layer formed by co-extrusion with the heat seal layer and a layer formed by sand lamination. The thickness of the layer formed by sand lamination is preferably 10 to 20 μm, from the viewpoints that the transmittance mentioned above is likely to be 75% or more and the haze value is likely to be less than 30%.

[0069] In addition to the above-described steps, the manufacturing method according to this embodiment may, if necessary, include antistatic treatment of the surface of the base layer of the cover tape (the surface not in contact with the intermediate layer). Examples of antistatic agents include those described above, and preferred examples of these are also the same. The antistatic treatment can be carried out by a roll coater using a gravure roll, a lip coater, a spray, or the like. Furthermore, in order to apply these antistatic agents uniformly, it is preferable to perform corona discharge treatment or ozone treatment on the film surface before the antistatic treatment, and corona discharge treatment is particularly preferable.

[0070] As described above, the cover tape according to the first embodiment is resistant to moisture absorption even under high temperature and high humidity conditions. In one embodiment, the moisture absorption rate of the cover tape under the following conditions is preferably 5000 ppm by mass or less. In a preferred embodiment, the moisture absorption rate may be 4500 ppm by mass or less, 4000 ppm by mass or less, or 3500 ppm by mass or less. <Condition> As a pretreatment, the cover tape is stored under dry conditions of 60°C / 20% RH for 12 hours, followed by 24 hours at 60°C / 90% RH. After that, the moisture absorption rate of the cover tape is measured at a holding temperature of 280°C according to JIS K0068:2001 "Karl Fischer titration method, moisture evaporation-coulometric titration method."

[0071] [Application] The cover tape according to the first embodiment can be used as a cover tape for an electronic component package. The cover tape according to the first embodiment has low moisture absorption under high temperature and high humidity conditions. Therefore, it can be used, for example, as a low-moisture-absorption cover tape for an electronic component package. Furthermore, the cover tape according to the first embodiment has good visibility, so it can be used, for example, as a high-visibility cover tape for an electronic component package.

[0072] [Electronic component packaging] A second embodiment of the present disclosure relates to an electronic component packaging body. A package containing electronic components, etc. (hereinafter referred to as "electronic component package") can be obtained, for example, by placing the electronic components, etc. in recesses in a carrier tape for storing the electronic components, etc., and then using a cover tape as a lid, continuously heat-sealing both longitudinal edges of the cover tape using a heat iron or the like to package the components, and then winding the package onto a reel. Packaged in this form, the electronic components, etc. are stored and transported. The electronic component package according to the second embodiment can be used to store and transport various electronic components, such as connectors, ICs, diodes, transistors, capacitors, resistors, and LEDs.

[0073] The electronic component package is transported using holes called sprocket holes for transporting the carrier tape, which are provided on the longitudinal edge of the carrier tape, while the cover tape is intermittently peeled off.The electronic components are then removed using a component mounting device, while checking the presence, orientation, and position of the electronic components, and are then mounted on a board.

[0074] <Carrier tape> The carrier tape included in the electronic component packaging according to the second embodiment is a strip-shaped material approximately 4 mm to 100 mm wide and having a recess for storing electronic components. When the cover tape according to the first embodiment is heat-sealed as a lid, the material of the carrier tape is not particularly limited, but carrier tapes containing polystyrene-based resins, polyester-based resins, or polycarbonate-based resins are suitable. The carrier tape may be imparted with conductivity by incorporating carbon black or carbon nanotubes into the resin; or may be imparted with a surfactant-based antistatic agent such as a cationic, anionic, or nonionic antistatic agent, or a persistent antistatic agent such as polyether ester amide; or may be imparted with antistatic properties by applying a coating liquid to the surface in which a surfactant-based antistatic agent or a conductive material such as polypyrrole or polythiophene is dispersed in an organic binder such as an acrylic resin.

[0075] When storing or transporting electronic component packages, it is necessary to prevent moisture absorption by the electronic component packages, including the cover tape, due to changes in temperature and humidity, and to prevent problems with the stored contents (electronic components) caused by this. Furthermore, it is also required that the orientation and front / back of the enclosed electronic components be confirmed from the cover tape side, and that serial numbers printed on the surfaces of the electronic components be detected from the cover tape side. The electronic component package according to the second embodiment includes the aforementioned cover tape, making it less likely to absorb moisture even under high temperature and high humidity conditions. Therefore, problems with the electronic components caused by moisture absorption by the cover tape are also easily prevented. Furthermore, the electronic component package according to the second embodiment has good visibility, making it possible to check for defects in the enclosed electronic components from the cover tape side.

[0076] Furthermore, the electronic component packaging is inspected by an IR camera to detect defects in the enclosed electronic components and to recognize circuits printed on the electronic components, etc. The electronic component packaging according to the second embodiment includes a cover tape that has high transmittance in the near-infrared wavelength range and a small haze value, and therefore has good visibility with an IR camera.

[0077] Another embodiment of the present disclosure is a method for suppressing moisture absorption by a cover tape under high temperature and high humidity conditions and improving visibility of the cover tape by controlling the transmittance of the cover tape at wavelengths of 1300 to 1500 nm to 75% or more and controlling the haze value to less than 30%. The method preferably further includes controlling the transmittance of the cover tape at wavelengths of 1200 to 1600 nm to 75% or more. Furthermore, the method preferably includes controlling the rate of change of the transmittance (T2) at a wavelength of 1600 nm relative to the transmittance (T1) at a wavelength of 1200 nm, as expressed by the following formula (1), to 90% or more. (T2 / T1) × 100(%) (1) [Example]

[0078] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following description.

[0079] <Production of cover tapes 1 to 7> The thermoplastic resins listed in Table 1 were selected as the thermoplastic resins constituting each layer. The thickness of each layer was determined as listed in Table 1. Then, following the steps (2) to (5) described above, a base layer, an intermediate layer, a heat-seal layer, and an antistatic layer were laminated in this order. Specifically, the resin composition for the heat-seal layer was extruded using a single-screw extruder by the T-die method to form a heat-seal layer. Next, the formed heat-seal layer and a base layer (PET film) were extrusion-sand-laminated with a molten resin composition for the intermediate layer, thereby laminating the base layer, intermediate layer, and heat-seal layer in this order. Furthermore, an antistatic layer was coated on the heat-seal layer and dried to obtain cover tapes 1 to 7. For cover tapes 2 to 6, an anchor coat layer (urethane adhesive) was provided on the base layer, and then an intermediate layer was laminated on the surface of the anchor coat layer.

[0080] <Production of cover tapes 8 and 9> The thermoplastic resins listed in Table 1 were selected as the thermoplastic resins constituting each layer, and the thickness of each layer was determined as listed in Table 1. Then, the base layer, intermediate layer, heat seal layer, and antistatic layer were laminated according to the above-mentioned steps (2) to (5). Cover tapes 8 to 9 were manufactured in the same manner as cover tapes 1 to 7, except that anchor coat layers were provided between the base layer and intermediate layer, and between the intermediate layer and heat seal layer.

[0081] [Table 1]

[0082] The components listed in Table 1 are as follows: <Base material layer> PET: Biaxially oriented polyethylene terephthalate film <Middle class> m-LLDPE Polyamide resin (nylon) <Heat seal layer> Styrene-based resin 1: Resin composition containing SBC and SB Styrene-based resin 2: SEBS Styrene-based resin 3: SB Ethylene resin: LLDPE Mixed resin: Resin composition containing SB and LLDPE (containing LLDPE as the main component) <Antistatic layer> Antistatic agent 1: A mixture of an ionic liquid (1-ethyl-3-methylimidazolium ethyl sulfate), a quaternary ammonium salt (ethyl dimethyl lauryl ammonium ethyl sulfate), and polyethylene glycol (antistatic agent concentration: 0.5% by mass). Antistatic agent 2: ATO Antistatic agent 3: Aluminum oxide Antistatic agent 4: Barium sulfate Antistatic agent 5: A mixture of barium sulfate and tin oxide In addition, the notation "-" in Table 1 means that no anchor coat layer was provided.

[0083] [Examples 1 to 6 and Comparative Examples 1 to 3] For cover tapes 1 to 9, the transmittance and haze value were measured by the following method. Furthermore, the moisture absorption rate was evaluated under high temperature and high humidity conditions as follows. Furthermore, electronic component packages were produced by the following method, and visibility was evaluated. The results are shown in Table 2.

[0084] <Transmittance> The transmittance of cover tapes 1 to 9 at wavelengths of 1200 to 1600 nm was measured by the following method, and the results are shown in Table 2 and FIG. The measurement and analysis equipment used was an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu Corporation, product name "UV-3600") and a multipurpose large sample chamber (φ60 mm, with built-in integrating sphere; Shimadzu Corporation, product name "MPC-3100"). First, baseline correction was performed without cover tape, and then the cover tape was attached and the spectral transmittance was measured using the integrating sphere at wavelengths of 1200 to 1600 nm.

[0085] <Haze value> The haze values ​​of cover tapes 1 to 9 were measured in accordance with JIS K7361-1:1997 using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "Haze Meter NDH 7000").

[0086] <Evaluation of moisture absorption rate under high temperature and humidity conditions> The moisture absorption rates of cover tapes 1 to 9 were measured by the following method. As a pretreatment, the cover tape was stored under dry conditions at 60°C / 20% RH for 12 hours. After 24 hours at 60°C / 90% RH, the moisture absorption rate of the cover tape was measured at a holding temperature of 280°C according to JIS K0068:2001, "Karl Fischer titration method, moisture evaporation-coulometric titration method." Evaluation was also conducted according to the following criteria, with a rating of B or higher considered a pass. The results are shown in Table 2. (Evaluation criteria) Good: The moisture absorption rate under high temperature and humidity conditions was less than 3000 mass ppm. Acceptable: The moisture absorption rate under high temperature and high humidity conditions was 3000 mass ppm or more and less than 5000 mass ppm. Unacceptable: The moisture absorption rate under high temperature and humidity conditions was 5000 mass ppm or more.

[0087] <Visibility evaluation> An electronic component (manufactured by Toshiba Corporation, product name "TCR2EN30") with a surface facing the cover tape measuring 0.8 mm x 0.8 mm square and with 0.25 mm characters printed on the surface was housed in a carrier tape. The cover tape was then heat-sealed to the carrier tape under the following conditions: sealing temperature: 150°C, sealing pressure: 0.5 kgf, sealing time: 0.3 seconds, and sealing time: 1 time, to create an electronic component package. The electronic component packaged inside was then photographed from the cover tape side using a digital microscope (Opto Science Corporation, product name "Dino-Lite Edge AM4815ZT") at a magnification of 150x. Images taken from the cover tape side in which the orientation of the electronic component could be confirmed and the characters were clearly readable were deemed pass, while images in which the orientation of the electronic component could not be confirmed or the characters were unclear and unreadable were deemed fail.

[0088] [Table 2]

[0089] As shown in Table 2 and FIG. 1, Examples 1 to 6 (cover tapes 1 to 6), which had a transmittance of 75% or more at wavelengths of 1300 to 1500 nm and a haze value of less than 30%, exhibited low moisture absorption and good visibility under high temperature and high humidity conditions. Cover tape 7 of Comparative Example 1, which had a transmittance of 75% or more at wavelengths of 1300 to 1500 nm but a haze value of 30% or more, exhibited low moisture absorption under high temperature and high humidity conditions but poor visibility. Furthermore, Comparative Examples 2 and 3 (cover tapes 8 and 9), which had a haze value of less than 30% but a transmittance of less than 75% at wavelengths of 1300 to 1500 nm, exhibited good visibility but very high moisture absorption under high temperature and high humidity conditions. These results confirm that the cover tape according to the present disclosure exhibits low moisture absorption and good visibility under high temperature and high humidity conditions.

[0090] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure are set forth below. [1] A cover tape having a transmittance of 75% or more at wavelengths of 1300 to 1500 nm and a haze value of less than 30%. [2] The cover tape according to [1], which has a transmittance of 75% or more at wavelengths of 1200 to 1600 nm. [3] The cover tape according to [1] or [2], wherein the rate of increase or decrease of the transmittance (T2) at a wavelength of 1600 nm relative to the transmittance (T1) at a wavelength of 1200 nm, as represented by the following formula (1), is 90% or more. (T2 / T1) × 100(%) (1) [4] The cover tape according to any one of [1] to [3], which does not contain a polyamide resin. [5] At least a base layer, an intermediate layer, and a heat seal layer are laminated in this order, The cover tape according to any one of [1] to [4], wherein the intermediate layer contains a polyolefin resin. [6] At least a base layer, an intermediate layer, and a heat seal layer are laminated in this order, The cover tape according to any one of [1] to [5], wherein the intermediate layer does not contain a polyamide resin. [7] The cover tape according to [5] or [6], wherein the thickness of the heat seal layer is less than 20 μm. [8] The cover tape according to any one of [1] to [7], which is for use in packaging for electronic components. [9] An electronic component packaging body comprising the cover tape according to any one of [1] to [8].

Claims

1. A cover tape having a transmittance of 75% or more at wavelengths of 1300 to 1500 nm and a haze value of less than 30%.

2. The cover tape according to claim 1, which has a transmittance of 75% or more at wavelengths of 1200 to 1600 nm.

3. 3. The cover tape according to claim 1, wherein the rate of change in transmittance (T2) at a wavelength of 1600 nm relative to the transmittance (T1) at a wavelength of 1200 nm, as represented by the following formula (1), is 90% or more. (T2 / T1)×100(%)...(1)

4. The cover tape according to claim 1 or 2, which does not contain a polyamide resin.

5. At least a base layer, an intermediate layer, and a heat seal layer are laminated in this order, The cover tape according to claim 1 or 2, wherein the intermediate layer comprises a polyolefin resin.

6. At least a base layer, an intermediate layer, and a heat seal layer are laminated in this order, The cover tape according to claim 1 or 2, wherein the intermediate layer does not contain a polyamide-based resin.

7. The cover tape of claim 5 , wherein the heat seal layer has a thickness of less than 20 μm.

8. The cover tape according to claim 1 or 2, which is for use in packaging for electronic components.

9. An electronic component package comprising the cover tape according to claim 1 or 2.

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