Cover film and electronic component packaging

Abstract

This disclosure provides a cover film that offers good visibility of electronic components in image sensor camera inspection. [Solution] A cover film, The cover film is laminated in the following order: (A) a base layer, (B) at least one intermediate layer, and (C) a heat seal layer. A cover film wherein the scratch resistance measured under the following condition 1 on the outermost surface of the heat-seal layer (C) opposite to the surface in contact with the (B) at least one intermediate layer is 25 mN or more when an applied load is applied. [Condition 1] Stylus: Made of sapphire, tip diameter 500 μm Scratching speed: 10 μm / second Load condition: 100mN / 60 seconds Excitation conditions: Off

Description

[Technical Field]

[0001] This disclosure relates to cover films and electronic component packaging. [Background technology]

[0002] With the miniaturization of electronic devices, the electronic components used are also becoming smaller and more high-performance, and in addition, the assembly process of electronic devices is now being carried out to automatically mount components onto printed circuit boards. Surface-mount electronic components are housed in a carrier tape that has a continuous series of thermoformed pockets that can accommodate the shape of the electronic components. After housing the electronic components, a cover film is placed on top of the carrier tape as a lid material, and both ends of the cover film are continuously heat-sealed in the longitudinal direction with a heated sealing bar to form a package. As for the cover film material, a biaxially oriented polyester film is used as the base material, with a heat-seal layer of thermoplastic resin laminated on top. As for the carrier tape, mainly thermoplastic resins such as polystyrene and polycarbonate are used. Furthermore, there are techniques for adding conductive fine particles such as tin oxide or zinc oxide to the heat seal layer (for example, Patent Documents 1-3), and techniques for adding hydrazide compounds (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Public Gazette No. 2019 / 087999 [Patent Document 2] Japanese Patent Publication No. 2018-090326 [Patent Document 3] Japanese Patent Publication No. 2019-026384 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In recent years, various electronic components such as capacitors, resistors, ICs, LEDs, connectors, and switching elements have undergone remarkable miniaturization, weight reduction, and thinning. Electronic components are inspected while still in their packaging for the presence of components, their orientation, and for any missing or bent leads. Inspection of electronic components in packaging involves taking images through the cover film using image sensor cameras such as CCD (Charge Coupled Device) cameras and CMOS (Complementary Metal-Oxide-Semiconductor) cameras, and then performing image analysis.

[0005] The object of this disclosure is to provide a cover film that has good visibility of electronic components in image sensor camera inspection. [Means for solving the problem]

[0006] It is a cover film, The cover film is laminated in the following order: (A) a base layer, (B) at least one intermediate layer, and (C) a heat seal layer. A cover film wherein the scratch resistance measured under the following condition 1 on the outermost surface of the heat-seal layer (C) opposite to the surface in contact with the (B) at least one intermediate layer is 25 mN or more when an applied load is applied. [Condition 1] Stylus: Made of sapphire, tip diameter 500 μm Scratching speed: 10 μm / second Load condition: 100mN / 60 seconds Excitation conditions: Off

[0007] This disclosure includes the following aspects: It is a cover film, The cover film is laminated in the following order: (A) a base layer, (B) at least one intermediate layer, and (C) a heat seal layer. A cover film wherein the scratch resistance measured under the following condition 1 on the outermost surface of the heat-seal layer (C) opposite to the surface in contact with the (B) at least one intermediate layer is 25 mN or more when an applied load is applied. [Condition 1] Stylus: Made of sapphire, tip diameter 500μm Scratch speed: 10μm / second Load condition: 100mN / 60 seconds Vibration condition: Cut [Advantages of the Invention]

[0008] According to the present disclosure, it is possible to provide a cover film having good visibility of electronic components in image sensor camera inspection. [Brief Description of the Drawings]

[0009] [Figure 1] It is a schematic cross-sectional view showing the layer structure of the cover film according to an embodiment. [Modes for Carrying Out the Invention]

[0010] Hereinafter, an embodiment of the present disclosure will be described in detail. However, the scope of the present disclosure is not limited to the embodiment described here, 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. When a plurality of upper limit values and lower limit values are described for a specific parameter, any upper limit value and lower limit value among these can be combined to form a suitable numerical range. The lower limit value and / or upper limit value of the numerical range described in the present disclosure are numerical values within that numerical range, and can be replaced with the numerical values shown in the examples. The expression "X~Y" indicating a numerical range means "X or more and Y or less". When a specific description of an embodiment applies to other embodiments, the description may be omitted in other embodiments.

[0011] [Cover Film] The cover film according to this embodiment has a (A) base material layer, (B) at least one intermediate layer, and (C) heat seal layer laminated in this order, The cover film is such that the scratch resistance measured under the following condition 1 on the outermost surface of the heat-seal layer (C) opposite to the surface in contact with the (B) at least one intermediate layer is 25 mN or more when the applied load is 25 mN or more. [Condition 1] Stylus: Made of sapphire, tip diameter 500 μm Scratching speed: 10 μm / second Load condition: 100mN / 60 seconds Excitation conditions: Off

[0012] The above scratch resistance is preferably measured under conditions of 23°C and 50% humidity.

[0013] In image sensor camera inspections of CCDs, CMOS sensors, etc., abnormalities may be detected even if there are no abnormalities in inspection items such as the presence or absence of components, the orientation of components, or defects or bends in leads. One possible reason for this is that immediately after heat sealing or during transportation, electronic components may come into contact with the heat seal layer of the cover film or adhere to the heat seal layer due to static electricity, causing scratches or whitening due to friction on the surface of the heat seal layer facing the electronic components. When scratches or whitening occur on the surface of the heat seal layer, the visibility by the image sensor camera decreases. The cover tape according to the present disclosure has a surface of the heat seal layer facing the electronic components housed in the carrier tape that has scratch resistance to an applied load of 25 mN or more, so that the electronic components are easily visible in image sensor camera inspections. As a result, it is easier to perform normal inspections of electronic components.

[0014] In one embodiment, the scratch resistance is preferably 25 to 90 mN, more preferably 30 to 70 mN, and even more preferably 40 to 65 mN. If the above scratch resistance is achieved under an applied load of 25-90 mN, even if the corners of electronic components come into contact with the heat seal layer due to shaking during transportation, the surface of the heat seal layer is less likely to be scratched. Furthermore, even if electronic components come into contact with or adhere to the heat seal layer due to static electricity, the surface of the heat seal layer is less likely to whiten. As a result, it becomes a cover tape that provides good visibility of electronic components during image sensor camera inspection.

[0015] There are no limitations on the method for adjusting scratch resistance. For example, one method is to use a highly rigid (hard) resin as the resin constituting the heat seal layer. However, using a hard resin in the heat seal layer may reduce the heat sealability with the carrier tape. Therefore, from the viewpoint of achieving both scratch resistance and heat sealability, it is preferable to adjust scratch resistance by devising the physical properties of the resin contained in the intermediate layer (B) as well as the resin contained in the heat seal layer (C). For example, if the intermediate layer (B) contains a thermoplastic resin (X) having a predetermined shear storage modulus G' as described later, and the heat seal layer (C) contains a thermoplastic resin (Y) (acrylic resin) having a predetermined glass transition temperature Tg (°C) as described later, it is easier to improve scratch resistance while maintaining excellent heat sealability.

[0016] <(A) Base material layer> (A) The base layer is preferably a layer containing biaxially oriented polyester or biaxially oriented nylon, and biaxially oriented polyethylene terephthalate (PET), biaxially oriented polyethylene naphthalate (PEN), biaxially oriented 6,6-nylon, and biaxially oriented 6-nylon can be used particularly suitably. In addition to those that are normally used as biaxially oriented PET, biaxially oriented PEN, biaxially oriented 6,6-nylon, and biaxially oriented 6-nylon, materials that have an antistatic agent coated or kneaded into them for antistatic treatment, or materials that have been treated with corona treatment or easy-adhesion treatment can be used. The thickness of the base layer is not limited, but is preferably 12 to 25 μm, more preferably 12 to 23 μm, and even more preferably 12 to 16 μm. A thickness of 12 μm or more makes it easier to suppress film breakage when peeling off the cover film. A thickness of 25 μm or less makes it easier to prevent a decrease in heat sealability to the carrier tape and can also reduce costs.

[0017] <(B) Middle layer> The cover film according to this embodiment has (A) a base layer on which (B) at least one intermediate layer (hereinafter also simply referred to as "(B) intermediate layer") is laminated. The (B) intermediate layer may be laminated on one side of the (A) base layer via an adhesive layer. The (B) intermediate layer is provided between the (A) base layer and the (C) heat seal layer.

[0018] (B) The resin contained in the intermediate layer is preferably a thermoplastic resin. The thermoplastic resin is not limited, but in one embodiment, (B) at least one intermediate layer has a shear storage modulus G' at 30°C measured under the following condition 2, which is 5.0 × 10 5 ~4.0×10 8 It is preferably Pa, and more preferably 6.0 × 10 5 ~4.0×10 8 Pa is more preferably 2.0 × 10 6 ~2.0×10 8 It is preferable to include a thermoplastic resin (X) which is Pa (hereinafter also referred to as "thermoplastic resin (X)"). [Condition 2] Dynamic viscoelasticity measuring device Measurement mode: Shear Heating rate: 5°C / min Frequency: 1Hz Strain condition: 0.0005 (B) At least one intermediate layer has a shear storage modulus G' at 30°C measured under condition 2 above, which is 5.0 × 10⁻⁶. 5 ~4.0×10 8 By including a thermoplastic resin (X) which is Pa, scratches and whitening of the (C) heat seal layer become less likely to occur even if electronic components come into contact with or adhere to the (C) heat seal layer.

[0019] The material of the thermoplastic resin (X) is not limited, but from the viewpoint of easily increasing the shear storage modulus G', it is preferable to include a resin composition containing a styrene-based resin mainly composed of a styrene-diene block copolymer and an ethylene-α-olefin random copolymer, or a hydrogenated aromatic vinyl-conjugated diene copolymer having an aromatic vinyl group content of 15 to 35% by mass, or an ethylene-vinyl acetate copolymer containing 75 to 91% by mass of olefin components, or a combination thereof. Among these, hydrogenated styrene-isoprene copolymer resins and hydrogenated styrene-butadiene copolymer resins having a styrene ratio of 15 to 35% by mass are suitable for use because they exhibit less variation in peel strength when peeling the cover film.

[0020] (B) The intermediate layer consists of one or more layers, preferably two or more layers, and may consist of two to five layers, two or three layers, or just two layers. If the intermediate layer consists of two or more layers, at least one of the layers should contain the thermoplastic resin (X) having the above-mentioned shear storage modulus G', and from the viewpoint of further suppressing scratches and whitening of the heat seal layer (C), it is preferable that the thermoplastic resin (X) is contained in the layer of the intermediate layer (B) that has a surface in contact with the heat seal layer (C).

[0021] In one embodiment, the (B) intermediate layer preferably includes a (B1) first intermediate layer and a (B2) second intermediate layer. In this case, the (B1) first intermediate layer and the (B2) second intermediate layer are preferably distinguished by differences in the composition and / or content of the resin or other components they contain, and / or by differences in the thickness of the layers.

[0022] (B) Preferably, the intermediate layer is laminated in the following order: (A) base layer, (B2) second intermediate layer, (B1) first intermediate layer, and (C) heat seal layer. In one preferred embodiment, from the viewpoint of further suppressing scratches and whitening of the (C) heat seal layer, the thermoplastic resin (X) is included in the (B1) first intermediate layer.

[0023] ((B1) First intermediate layer) (B1) The first intermediate layer is a layer included in the (B) intermediate layer, and preferably has a surface that contacts the (C) heat-sealing layer described later.

[0024] In one embodiment, from the viewpoint of further suppressing scratches and whitening of the (C) heat-sealing layer, the (B1) first intermediate layer preferably contains a thermoplastic resin (X) having a specific shear storage modulus G' (Pa).

[0025] The shear storage modulus G' at 30 °C is preferably 5.0×10 5 ~4.0×10 8 Pa, more preferably 6.0×10 5 ~4.0×10 8 Pa, and even more preferably 2.0×10 6 ~2.0×10 8 Pa. When the thermoplastic resin (X) with a shear storage modulus G' at 30 °C in the range of 5.0×10 5 ~4.0×10 8 Pa is included in the (B1) first intermediate layer, the effect of relaxing the stress from the components applied to the heat-sealing layer is more easily obtained.

[0026] In one embodiment, it is preferable that the (B1) first intermediate layer contains the thermoplastic resin (X), and the (C) heat-sealing layer described later contains a thermoplastic resin (Y) (acrylic resin) having a predetermined glass transition temperature Tg (°C). When the (B1) first intermediate layer contains the thermoplastic resin (X) and the (C) heat-sealing layer described later contains a thermoplastic resin (Y) (acrylic resin) having a predetermined glass transition temperature Tg (°C), the scratch resistance is likely to be high. As a result, it becomes easier to prevent whitening caused by friction between the electronic components stored in the carrier tape and the cover tape, and scratches generated on the surface of the heat-sealing layer facing the electronic components. As a result, it becomes easier to ensure good visibility of the electronic components in the image sensor camera inspection.

[0027] (B1) The thickness of the first intermediate layer is not limited, but is preferably in the range of 0.1 to 15 μm, and more preferably in the range of 0.1 to 10 μm. (B1) If the thickness of the first intermediate layer is 0.1 μm or more, scratches and whitening will be less likely to occur even if electronic components come into contact with or adhere to the (C) heat seal layer. In addition, sufficient peel strength can be achieved when the cover film is heat-sealed to the carrier tape. (B1) If the thickness of the first intermediate layer is 15 μm or less, variations in peel strength will be less likely to occur when peeling the cover film. Note that this (B1) first intermediate layer is usually formed by extrusion film formation, but if it is formed by a coating method, the thickness referred to here is the thickness after drying.

[0028] (B1) In the first intermediate layer, organic particles such as spherical or crushed acrylic particles, styrene particles, or silicone particles, or inorganic particles such as talc particles, silica particles, mica particles, calcium carbonate, or magnesium carbonate can be added to prevent blocking when the cover film is wound. In particular, the reduction in transparency when acrylic particles or silica particles are added is small, making them more suitable for use. The maximum frequency diameter obtained from the particle mass distribution curve is preferably 1 to 10 μm, and more preferably 2 to 7 μm. When the maximum frequency diameter is 1 μm or more, the blocking prevention effect due to particle addition is more easily obtained. When it is 10 μm or less, costs can be reduced, and visible irregularities are less likely to occur on the surface of the heat seal layer of the cover film, making it easier to maintain a good appearance of the cover film. (B1) The mass fraction of fine particles in the first intermediate layer is preferably 0 to 15 mass%, and more preferably 5 to 10 mass%. Within this range of addition, a balance is achieved in terms of transparency, heat sealability, and blocking prevention effect.

[0029] ((B2) Second middle tier) (B2) The second intermediate layer is preferably provided directly on the (A) base layer. (B2) The resin constituting the second intermediate layer is preferably a low-density polyolefin that is particularly flexible and has appropriate rigidity. Examples of low-density polyolefins include low-density polyethylene (LDPE) and low-density polyolefins, but linear low-density polyethylene (hereinafter referred to as LLDPE) can be suitably used from the viewpoint of having excellent tear strength at room temperature. As for LLDPE, a density of 0.880 to 0.925 (×10) is particularly preferable. 3 kg / m 3 By using resin within the specified range, the adhesive layer resin is less likely to seep out from the edges of the cover film due to the heat and pressure during heat sealing. This not only reduces contamination of the soldering iron during heat sealing, but also softens the adhesive layer when the cover film is heat-sealed, mitigating uneven contact with the heat-sealing iron, thus making it easier to obtain stable peel strength when removing the cover film.

[0030] LLDPEs include those polymerized with a Tigler-type catalyst and those polymerized with a metallocene-based catalyst (hereinafter referred to as m-LLDPE). Because m-LLDPE has a narrowly controlled molecular weight distribution, it has particularly high tear strength, and it is especially preferable to use m-LLDPE as the second intermediate layer (B1) in this disclosure.

[0031] The above-mentioned m-LLDPE is a copolymer of ethylene and an α-olefin substituted with an olefin having 3 or more carbon atoms, preferably a linear, branched, or aromatic nucleus 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 monoolefins substituted with aromatic nuclei include styrene. These comonomers can be copolymerized with ethylene individually or in combination of two or more. In this copolymerization, polyenes such as butadiene, isoprene, 1,3-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene may be copolymerized.

[0032] (B2) The thickness of the second intermediate layer is not limited, but is preferably 5 to 50 μm, and more preferably 10 to 40 μm. (B2) If the thickness of the second intermediate layer is 5 μm or more, it is easier to mitigate uneven contact of the heat sealing iron when heat sealing the cover film to the carrier tape. If it is 50 μm or less, the total thickness of the cover film is not too thick, and sufficient peel strength is easily obtained when heat sealing the cover film to the carrier tape.

[0033] <(C) Heat seal layer> The cover film according to this embodiment preferably has a configuration in which a heat-seal layer (C) is formed on the surface of a first intermediate layer (B1). (C) The heat-seal layer is a layer that has the effect of heat-welding to the carrier tape. By heat-welding the heat-seal layer of the cover film to the carrier tape, an electronic component packaging body is produced that has a lid material made of the cover film and a carrier tape made of thermoplastic resin.

[0034] (C) The heat seal layer contains a thermoplastic resin. From the viewpoint of easily improving scratch resistance, a thermoplastic resin (Y) mainly composed of an acrylic resin is preferred as the thermoplastic resin. Here, "main component" means that the resin contains more than 50% by mass, 70% by mass or more, or 90% by mass or more of an acrylic resin. Preferably used acrylic resins include styrene-acrylic copolymers and acrylic emulsions. The acrylic resin may be used alone or in combination of two or more types. Styrene-acrylic copolymers are copolymers comprising a styrene monomer and a (meth)acrylic monomer as essential components. Examples of styrene monomers include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and p-phenylstyrene, with styrene being particularly preferred. These styrene monomers can be used individually or in combination of two or more. Examples of (meth)acrylic monomers include acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate, and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate. These (meth)acrylic monomers can be used individually or in combination of two or more. In addition, a small amount of other monomer copolymerized with styrene monomers and (meth)acrylic monomers may also be used. Examples of acrylic emulsions include those produced by emulsion polymerization of monomers such as acrylic acid esters using an emulsifier.

[0035] In one embodiment, the acrylic resin is preferably one with a glass transition temperature of 15°C or higher and less than 40°C. Furthermore, the glass transition temperature is preferably 18 to 35°C, and more preferably 25 to 35°C. A glass transition temperature of 15°C or higher and less than 40°C makes it easier to achieve both the desired scratch resistance and sealing properties.

[0036] The glass transition temperature is measured in accordance with JIS K 7121. A PerkinElmer Japan input-compensated differential scanning calorimeter (DSC) DSC8500 is used. A 5 mg sample of acrylic resin is placed in an aluminum pan under nitrogen gas sealing, and the temperature is increased from -50°C to 150°C at a heating rate of 10°C per minute. As the temperature rises, the intersection of the reference line and the tangent line at the inflection point where the temperature changes to the endothermic side is read as the glass transition temperature.

[0037] As mentioned above, the shear storage modulus G' is 5.0 × 10⁻⁶ 5 ~4.0×10 8 By using a heat-seal layer (C) containing a thermoplastic resin (X) in the Pa range in the first intermediate layer (B1), and a thermoplastic resin (Y) (acrylic resin) having a glass transition temperature Tg (°C) in the aforementioned range, it is easy to achieve both scratch resistance and heat-sealability. As a result, even if electronic components come into contact with or adhere to the heat-seal layer (C), scratches and whitening of the heat-seal layer (C) are less likely to occur, and the visibility of electronic components in image sensor camera inspection is improved. In addition, a cover film with excellent heat-sealability with the carrier tape is easily obtained.

[0038] In one embodiment, the (C) heat seal layer preferably contains an acrylic resin and an inorganic filler. The acrylic resin is as described above. The inorganic filler can contain at least one of the following: conductive tin oxide particles, conductive zinc oxide particles, and conductive titanium oxide particles. In particular, tin oxide doped with antimony, phosphorus, or gallium is preferable because it improves conductivity and reduces the transparency of the heat seal layer. Conductive tin oxide particles, conductive zinc oxide particles, and conductive titanium oxide particles can be spherical or needle-shaped. When needle-shaped tin oxide doped with antimony is used in particular, a cover film with particularly good antistatic performance can be obtained. When good antistatic performance is achieved, it is easier to prevent electronic components from adhering to the (C) heat seal layer due to static electricity, so scratches and whitening are less likely to occur on the (C) heat seal layer, and the visibility of electronic components is better in image sensor camera inspection.

[0039] The inorganic filler content is preferably 100 to 500 parts by mass, more preferably 100 to 300 parts by mass, and particularly preferably 100 to 200 parts by mass, relative to 100 parts by mass of the thermoplastic resin (Y) constituting the (C) heat seal layer. When the amount of inorganic filler added is 100 parts by mass or more, the antistatic or conductive properties of the (C) heat seal layer side of the cover film tend to be sufficient, and it becomes easier to prevent scratches on the surface of the heat seal layer facing the electronic components due to static electricity adhesion or whitening due to friction. If the amount is 500 parts by mass or less, it becomes easier to obtain sufficient peel strength by heat sealing.

[0040] (C) The thickness of the heat seal layer is preferably 0.1 to 5 μm, more preferably 0.1 to 3 μm, and even more preferably 0.1 to 0.5 μm. When the heat seal thickness is 0.1 μm or more, the (C) heat seal layer is more likely to exhibit sufficient peel strength. When the thickness of the heat seal layer is 5 μm or less, the increase in cost can be suppressed, and variations in peel strength when peeling the cover film can be easily prevented.

[0041] <Other layers> In the cover film according to this embodiment, a second intermediate layer (B2) can be laminated on one side of the base layer (A) via an adhesive layer. That is, the cover film may have an adhesive layer between the base layer (A) and the intermediate layer (B) (particularly the second intermediate layer (B2)). The adhesive layer can be selected from polyurethane, polyester, polyolefin, etc., and two or more of these may be used in combination. The thickness of the adhesive layer is preferably 1 to 5 μm, more preferably 2 to 4 μm, and even more preferably 3 μm.

[0042] <Cover film> Figure 1 is a schematic cross-sectional view showing the layer structure of a cover film according to one embodiment. As shown in Figure 1, the cover film 1 includes (A) a base layer 2, (B2) a second intermediate layer 3, (B1) a first intermediate layer 4, and (C) a heat seal layer 5 in this order. The total thickness of the cover film is preferably 30 to 50 μm. A cover film thickness of 30 to 50 μm makes it easier to obtain a favorable sealing performance with respect to the carrier tape.

[0043] <Method for manufacturing cover film> The method for producing the above cover film is not particularly limited, and general methods can be used. Specifically, an adhesive such as polyurethane, polyester, polyolefin, or polyethyleneimine is applied to the surface of the biaxially oriented polyester film of the base layer (A), and the second intermediate layer resin composition constituting the second intermediate layer (B2) is extruded from a T-die and coated onto the adhesive-coated surface to form a two-layer film consisting of the base layer (A) and the second intermediate layer (B2). Furthermore, the first intermediate layer resin composition constituting the first intermediate layer (B1) can be applied to the surface of the second intermediate layer (B2) using, for example, a gravure coater, reverse coater, kiss coater, air knife coater, Meyer bar coater, dip coater, etc. to form the first intermediate layer (B1). In this case, it is preferable to perform corona treatment or ozone treatment on the surface of the second intermediate layer (B2) before coating, and corona treatment is particularly preferable. Furthermore, the desired cover film can be obtained by coating (B1) the first intermediate layer with (C) a resin composition for a heat seal layer using, for example, a gravure coater, reverse coater, kiss coater, air knife coater, Meyer bar coater, dip coater, etc.

[0044] Alternatively, the first intermediate layer (B1) and the second intermediate layer (B2) can be pre-fabricated by a T-die-casting method or an inflation method, and then a film can be obtained in which the biaxially oriented polyester film of the base layer (A), the second intermediate layer (B2), and the first intermediate layer (B1) are laminated in this order by a dry lamination method in which the films are bonded to the biaxially oriented polyester film of the base layer (A) via an adhesive such as polyurethane, polyester, or polyolefin. The desired cover film can then be obtained by applying a heat-seal resin composition constituting the heat-seal layer (C) to the surface of the first intermediate layer (B1).

[0045] Furthermore, the desired cover film can also be obtained by the sand lamination method. Specifically, a film constituting the (B1) first intermediate layer is manufactured by the T die-casting method or the inflation method. Next, a resin composition mainly composed of molten m-LLDPE is supplied between the (B1) first intermediate layer film and the (A) base layer film to form and laminate the (B2) second intermediate layer, thereby obtaining a film in which the (A) base layer, the (B2) second intermediate layer, and the (B1) first intermediate layer are laminated in this order. The desired film can then be obtained by applying the (C) heat seal layer to the surface on the (B1) first intermediate layer side. In this method as well, it is common to use a (A) base layer film with an adhesive coated on the lamination side.

[0046] In addition to the above steps, the (A) substrate layer of the cover film can be treated with an antistatic agent as needed. For example, surfactant-type antistatic agents such as anionic, cationic, nonionic, and betaine-type agents, polymer-type antistatic agents, and conductive agents dispersed in a binder can be applied using a roll coater with a gravure roll, a lip coater, a spray, etc. Furthermore, in order to uniformly apply these antistatic agents, it is preferable to treat the film surface with corona discharge or ozone before performing the antistatic treatment, and corona discharge treatment is particularly preferred.

[0047] [Electronic component packaging] The electronic component packaging relating to this disclosure comprises the cover film and carrier tape described above. The cover film is as described above and therefore will not be described here. A carrier tape is a strip-shaped material approximately 8 mm to 100 mm wide that has pockets for housing electronic components. When heat-sealing a cover film as a lid material, the material constituting the carrier tape is not particularly limited and commercially available materials can be used, such as polystyrene, polyester, polycarbonate, and polyvinyl chloride. When an acrylic resin is used for the heat-seal layer, a combination with a polystyrene and / or polycarbonate carrier tape is preferably used. Carrier tapes can be made conductive by kneading carbon black or carbon nanotubes into the resin, or they can have antistatic agents or conductive fillers kneaded into them, or they can have antistatic properties applied to the surface by coating it with a coating liquid in which a surfactant-type antistatic agent or conductive material such as polypyrrole or polythiophene is dispersed in an organic binder such as acrylic.

[0048] A package containing electronic components is obtained, for example, by placing electronic components in the electronic component storage section of a carrier tape, then using a cover film as a lid, continuously heat-sealing both longitudinal edges of the cover film, and winding it onto a reel. Electronic components are stored and transported in this form. The package containing electronic components is transported using holes called sprocket holes for carrier tape transport provided on the longitudinal edge of the carrier tape, and the cover film is intermittently peeled off. The electronic components are then removed by a component mounting device while confirming their presence, orientation, and position, and mounted onto a circuit board. Furthermore, when peeling off the cover film, if the peel strength is too low, it may peel off from the carrier tape, potentially causing the stored components to fall out. If it is too high, it may become difficult to peel off from the carrier tape, and there is a risk of tearing the cover film when peeling it off. Therefore, when heat-sealed at 120-220°C, a peel strength of 0.05-1.0N is preferable, and the variation in peel strength should preferably be less than 0.4N.

[0049] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of this disclosure are disclosed below. [1] A cover film, The cover film is laminated in the following order: (A) a base layer, (B) at least one intermediate layer, and (C) a heat seal layer. A cover film wherein the scratch resistance measured under the following condition 1 on the outermost surface of the heat-seal layer (C) opposite to the surface in contact with the (B) at least one intermediate layer is 25 mN or more when an applied load is applied. [Condition 1] Stylus: Made of sapphire, tip diameter 500 μm Scratching speed: 10 μm / second Load condition: 100mN / 60 seconds Excitation conditions: Off [2] The (B) at least one intermediate layer has a shear storage modulus G' at 30°C of 5.0 × 10⁻¹⁰ as measured under the following condition 2. 5 ~4.0×10 8 A cover film of [1] comprising a thermoplastic resin (X) which is Pa. [Condition 2] Dynamic viscoelasticity measuring device Measurement mode: Shear Heating rate: 5°C / min Frequency: 1Hz Strain condition: 0.0005 [3] The cover film according to [1] or [2], wherein the (C) heat seal layer comprises an acrylic resin and an inorganic filler. [4] The cover film according to [3], wherein the glass transition temperature (Tg) of the acrylic resin is 15°C or higher and less than 40°C. [5] The cover film according to [3], wherein the acrylic resin comprises butyl acrylate and / or butyl methacrylate. [6] The cover film according to [3], wherein the inorganic filler comprises antimond-doped tin oxide. [7] The cover film according to any one of [1] to [6], wherein the (B) at least one intermediate layer comprises (B1) a first intermediate layer and (B2) a second intermediate layer. [8] An electronic component packaging comprising a cover film as described in any of [1] to [7] and a carrier tape. Each configuration and its combination in each embodiment is an example, and additions, omissions, substitutions, and other modifications can be made as appropriate without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments. [Examples]

[0050] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0051] In the examples and comparative examples, the following resin raw materials were used for (A) the base layer, (B1) the first intermediate layer, (B2) the second intermediate layer, and (C) the heat seal layer.

[0052] ((A) Resin of the base layer) (a-1) Substrate: Biaxially oriented polyethylene terephthalate film, 16 μm thick ((B) At least one intermediate layer of resin) ((B1) The resin of the first intermediate layer) (b-1-1) Resin: Hydrogenated resin of styrene-butadiene-styrene triblock copolymer (SEBS), styrene-derived monomer unit content (hereinafter referred to as styrene component content) 30% by mass (b-1-2) Resin: Styrene-butadiene block copolymer (SBC) resin (styrene content 80%) (b-1-3) Resin: Styrene-butadiene block copolymer (SBC) resin (styrene content 40%) (b-1-4) Resin: Resin of ethylene-1-butene random copolymer (b-1-5) Resin: High-impact polystyrene resin (b-1-6) Resin: Ethylene-vinyl acetate copolymer resin (b-1-7) Resin: Styrene-isoprene block copolymer resin ((B2) Second intermediate layer resin) (b-2)m-LLDPE MFR 4.0g / 10min (measurement temperature 190℃, load 2.16kgf), density 0.904×10 3 kg / m 3 ((C) Resin of the heat-seal layer) (c-1-1) Styrene-acrylic copolymer emulsion (Tg 32℃) (c-1-2) Styrene-acrylic copolymer emulsion (Tg 18℃) (c-1-3) Acrylic copolymer emulsion (Tg 39℃) (c-1-4) Styrene-acrylic copolymer emulsion (Tg 26℃) (c-1-5) Acrylic copolymer emulsion (Tg 12℃) (c-1-6) Acrylic copolymer emulsion (Tg 44℃) (c-1-7) Acrylic copolymer emulsion (Tg 65℃) ((C) Inorganic filler to be added to the heat seal layer) (c-2-1) Conductive agent: Spherical antimond-doped tin oxide, number average major diameter 0.1 μm, water dispersion type, solid content concentration 30% by mass (c-2-2) Conductive agent: Needle-shaped antimond-doped tin oxide, number average major diameter 2 μm, water dispersion type, solid content concentration 20% by mass (c-2-3) Antistatic agent: Spherical tin oxide, primary particle size 2 nm, pH 10, Dispersant: Ammonia

[0053] (Examples 1-11, Comparative Examples 1-3, 5-6) Cover tapes for each example were prepared with the compositions shown in Tables 1 and 2. Specifically, the (B1) first intermediate layer resin composition and the (B2) second intermediate layer resin composition were extruded from separate single-screw extruders and laminated extruded using a multi-manifold T-die to obtain a two-layer film with a thickness of 10 μm for the (B1) first intermediate layer and a thickness of 20 μm for the (B2) second intermediate layer. Then, a polyurethane adhesive was applied to the (A) base layer (thickness 16 μm) to create an adhesive layer with a thickness of 3 μm, and the (B2) second intermediate layer surface of the two-layer film and the adhesive layer were bonded together by dry lamination. After corona treatment of the (B2) second intermediate layer surface, a (C) heat seal layer (thickness 0.4 μm) was formed to obtain a cover film with the configuration shown in Figure 1 (the adhesive layer is not shown in Figure 1). This cover film is constructed by laminating (A) a base layer, (B2) a second intermediate layer, (B1) a first intermediate layer, and (C) a heat-seal layer in this order.

[0054] (Comparative Example 4) (B) A cover film was prepared in the same manner as in Example 1, except that (B2) at least one intermediate layer was replaced with only the second intermediate layer.

[0055] (Comparative Example 7) (B) A cover film was prepared in the same manner as in Example 1, except that at least one intermediate layer was (B1) the first intermediate layer.

[0056] (Glass transition temperature of the heat seal layer) In accordance with JIS K7121, the glass transition temperature of the thermoplastic resin in the (C) heat seal layer was measured. Using a differential scanning calorimeter (DSC) (Perkin Elmer, "DSC8500"), the temperature was increased from -50°C to 150°C under a heating condition of 10°C / 60 seconds, and the glass transition temperature (°C) was measured under a nitrogen atmosphere. The results are shown in the (C) heat seal layer column of Tables 1 and 2.

[0057] (Shear storage modulus of the first intermediate layer) (B1) For each resin used in the first intermediate layer, the cross-sectional storage modulus G'(Pa) at 30°C was measured using a TA Instruments DHR-2 dynamic viscoelasticity rheometer, with the measurement mode set to shear, heating rate of 5°C / min, frequency of 1 Hz, and strain condition of 0.0005.

[0058] <Evaluation Method> The cover films prepared in each example and comparative example were evaluated as follows. These results are summarized in Tables 1 and 2, respectively.

[0059] (1) Sealing properties Using a taping machine (Shibuya Kogyo Co., Ltd., ETM-480), a 5.5 mm wide cover film was heat-sealed onto 8 mm wide polycarbonate carrier tape (manufactured by Denki Kagaku Kogyo Co., Ltd.) and polystyrene carrier tape (manufactured by Denki Kagaku Kogyo Co., Ltd.) at a sealing iron temperature of 160°C with a seal head width of 0.5 mm x 2, seal head length of 32 mm, seal pressure of 0.1 MPa, feed length of 4 mm, and seal time of 0.1 seconds x 8 times. After being left for 24 hours in an atmosphere of 23°C and 50% relative humidity, the cover film was peeled off at a speed of 300 mm per minute and a peeling angle of 170-180° in the same atmosphere of 23°C and 50% relative humidity. Films with an average peel strength in the range of 0.3-0.6 N were classified as having "excellent" sealing performance, those with an average peel strength of 0.2-0.8 N were classified as having "good" sealing performance, and those with an average peel strength outside the range of 0.2-0.8 N were classified as having "poor" sealing performance. The results are shown in the sealing performance column of Tables 1 and 2.

[0060] (2) Ultra-thin film scratch tester The ultrathin film scratch test was performed using an ultrathin film scratch tester (CSR5100, manufactured by Resca Co., Ltd.) with a stylus having a tip diameter of R500 (tip material: sapphire), a scratching speed of 10 μm / sec, a load condition of 100 mN / min, and excitation cutting conditions.

[0061] (3) Component vibration friction test Under conditions of 23°C and 50% relative humidity, an electronic component (Texas Instruments, SOT-223-6: 6.45mm x 3.45mm x 1.80mm) was loaded onto a polycarbonate carrier tape (manufactured by Denki Kagaku Kogyo Co., Ltd.), and then a cover film was heat-sealed at 190°C to create a 20cm tape-cut sample. One end of the tape-cut sample was fixed to a vibration tester (AS-ONE, ENVIRONMENTAL VIBRATION TESTER CV-101), and a friction vibration test with the electronic component was conducted at a frequency of 20Hz, acceleration of 1.5G, amplitude of 2mm, and time of 1 minute. Samples with no scratches on the heat-sealed surface of the cover film were classified as "Excellent," samples with scratches on one of the four corners of the electronic component were classified as "Good," and samples with scratches on two or more corners were classified as "Poor." The results are shown in the friction test with electronic component column of Tables 1 and 2.

[0062] (4) Visibility evaluation using a CMOS camera The visibility of the areas containing electronic components in the tape-cut samples evaluated in the component vibration friction test described above (3) was confirmed using an image processing inspection device (VISCO Technologies, VTV-9000) under the following conditions. [conditions] Camera resolution: 5 million Lens: 1.5x Field of view: 5.6mm x 4.7mm Resolution: 2.4 μm / pixel Lighting: Ring lighting Images obtained through image processing inspection were reviewed, and those where no white spots caused by scratches on the surface of the heat-seal layer of the cover film facing the electronic components were visible and the printing of the electronic components was clearly visible were classified as "Excellent," those where white spots were present but the printing of the electronic components was clearly visible were classified as "Good," and those where white spots were present and the printing of the electronic components was unclear were classified as "Poor." The results are shown in the "Visibility Evaluation by CMOS Camera" column of Tables 1 and 2.

[0063] [Table 1]

[0064] [Table 2] [Industrial applicability]

[0065] The cover film and electronic component packaging of this embodiment have industrial applicability because they can provide a cover film that allows for good visibility of electronic components during inspection with an image sensor camera. [Explanation of Symbols]

[0066] 1 Cover film 2 Base material layer 3. The second middle class 4. The first middle class 5 Heat seal layer

Claims

1. It is a cover film, The cover film is laminated in the following order: (A) a base layer, (B) at least one intermediate layer, and (C) a heat seal layer. A cover film wherein the scratch resistance measured under the following condition 1 on the outermost surface of the heat-seal layer (C) opposite to the surface in contact with the (B) at least one intermediate layer is 25 mN or more when an applied load is applied. [Condition 1] Stylus: Made of sapphire, tip diameter 500 μm Scratching speed: 10 μm / second Load condition: 100 mN / 60 seconds Excitation conditions: Off

2. The above (B) at least one intermediate layer has a shear storage modulus G' at 30°C measured under the following condition 2, which is 5.0 × 10 ５ ~4.0 x 10 ８ The cover film according to claim 1, comprising a thermoplastic resin (X) which is Pa. [Condition 2] Dynamic viscoelasticity measuring device Measurement mode: Shear Heating rate: 5°C / min Frequency: 1 Hz Strain condition: 0.0005

3. The cover film according to claim 1 or 2, wherein the (C) heat seal layer comprises an acrylic resin and an inorganic filler.

4. The cover film according to claim 3, wherein the glass transition temperature (Tg) of the acrylic resin is 15°C or higher and less than 40°C.

5. The cover film according to claim 3, wherein the acrylic resin comprises butyl acrylate and / or butyl methacrylate.

6. The cover film according to claim 3, wherein the inorganic filler contains antimond-doped tin oxide.

7. The cover film according to claim 1 or 2, wherein the (B) at least one intermediate layer includes (B1) a first intermediate layer and (B2) a second intermediate layer.

8. An electronic component packaging comprising a cover film according to claim 1 or 2 and a carrier tape.

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