JP6694387B2 - Cover film and electronic component package using the same - Google Patents

Description

  The present invention relates to a cover film used for a package of electronic parts and an electronic part package using the cover film.

  Along with the miniaturization of electronic devices, the miniaturization and high performance of electronic components used are also progressing. At the same time, in the assembly process of electronic devices, electronic components are automatically mounted on a printed circuit board. The surface-mounting electronic component is stored in a carrier tape in which embossed pockets that can be stored according to the shape of the electronic component are interlockedly formed. After accommodating the electronic components, a cover film is placed on the upper surface of the carrier tape as a lid material, and both ends of the cover film are continuously heat-sealed in the lengthwise direction with a heated seal bar to form a package. As the cover film material, a biaxially stretched polyester film on which a sealant layer of a thermoplastic resin is laminated is used.

  The cover film is peeled from the carrier tape by an automatic peeling device when the electronic component is mounted in the manufacturing process of the electronic device or the like. Therefore, as the function of the cover film, it is particularly important that the peel strength from the carrier tape is stable within an appropriate range. If the peel strength is too strong, the cover film may break, and if it is too weak, the cover film may peel off from the carrier tape when the carrier is transferred, and the electronic component that is the content may fall off. In addition, when the carrier is transferred, it may be exposed to a high temperature environment of 40 to 60 ° C., and the heat seal layer of the thermoplastic resin may be softened and the parts other than the heat sealed ends may be bonded to the carrier tape. However, the peel strength may increase. In particular, with the rapid increase in mounting speed, the peeling speed of the cover film has also become extremely high at 0.1 seconds or less / tact. At the time of peeling, a large impact stress is applied to the cover film. As a result, there is a problem called "film breakage" in which the cover film is cut.

  The peel strength of the cover film is 0.1 to 1.0 N for a carrier tape having a width of 8 mm and 0.1 to 1 for a carrier tape having a width of 12 mm to 56 mm when the peeling speed is set to 300 mm / min in JIS C0806-3. It is set to 3N. However, in the mounting process of electronic components, the peeling speed is faster than 300 mm / min, and in particular, when housing a large-sized connector component, it is often taped with the upper limit peeling strength, and as a result, the cover film is peeled off. It is easy to cause "a film break" when doing.

  On the other hand, the cover film may be required to have high transparency so that the electronic component that is a stored item can be easily identified. For example, in the inspection of electronic parts such as ICs, a method of discriminating defects such as deformation of IC pins by taking an image with a CCD camera on the cover film and analyzing the image is performed, and for that purpose, it is highly transparent. A cover film having properties is required. In such a usage method, a haze (fogging value) of 50% or less is required.

As a countermeasure against film breakage, a method has been proposed in which a layer having excellent impact resistance and tear propagation resistance such as polypropylene, nylon, or polyurethane is provided between a base material such as a biaxially stretched polyester film and a sealant layer (Patent: References 1 to 3). On the other hand, metallocene linear low-density polyethylene (LLDPE) having a specific gravity is used as the intermediate layer, and the adhesive layer between the intermediate layer and the base material layer has a low Young's modulus, so that stress propagation to the base material layer is improved. A method of preventing has been proposed (see Patent Document 4). Further, the seal temperature dependency of the peel-off strength, the change over time is small, and for the purpose of obtaining a stable seal film, a sealant resin composition is prepared by mixing polyethylene or polypropylene with styrene-butadiene-styrene block copolymer. A method for solving the problem has been proposed (see Patent Document 5). However, even with these methods, it has been difficult to sufficiently prevent film breakage during high-speed peeling of 100 m / min. As a measure against film breakage, a cover film has been proposed in which layers made of styrene-based hydrocarbon resin are coextruded to improve the adhesive force between layers (see Patent Document 6). However, in this method, the stability of the peel strength after heat sealing was insufficient.
JP-A-8-119373 Japanese Patent Laid-Open No. 10-250020 JP, 2000-327024, A JP, 2006-327624, A JP-A-8-324676 JP, 2007-90725, A

  An object of the present invention is to provide a cover film having a peel strength that is constant within a predetermined value range, excellent transparency, and less likely to cause “film breakage” during high-speed peeling.

  As a result of diligent studies on the above-mentioned problems, the present inventor provides a resin composition having a specific structure in an adhesive layer and a heat-sealing layer, which are located between a base material layer and an intermediate layer. The inventors have found that a cover film that overcomes the above problem can be obtained, and thus reached the present invention.

That is, the present invention is a cover film having (1) at least (A) base material layer, (B) adhesive layer, (C) intermediate layer and (D) heat seal layer, wherein (B) adhesive layer is The resin constituting the heat seal layer (D), which is composed of a cured product of a main agent containing a polyester resin and a curing agent containing 50% by mass or more of isophorone diisocyanate, contains 58% by mass to 82% by mass of the (d-1) olefin component. 50 mass% to 90 mass% of an olefin-based resin containing one or both of an olefin-styrene block copolymer containing mass% and an ethylene-vinyl acetate copolymer containing 75 mass% to 88 mass% of an olefin component; d-2) 10 mass% to 40 mass% of a potassium ionomer having an antistatic property, and (D) the surface resistance value of the outermost surface of the cover film on the heat seal layer side. A cover film to equal to or less than 10 ¹² Omega.

In another aspect, a cover film comprising at least (A) a base material layer, (B) an adhesive layer, (C) an intermediate layer, and (D) a heat-sealing layer having a heat-sealable resin, B) The adhesive layer is composed of a cured product of a two-component curable adhesive composed of a main agent and a curing agent, the main agent is a polyester resin, and 50% by mass or more of the curing agent is isophorone diisocyanate, (D) The resin constituting the heat seal layer is either (d-1) an olefin-styrene block copolymer containing 58 to 82 mass% of an olefin component or an ethylene-vinyl acetate copolymer containing 75 to 88 mass% of an olefin component. 50 to 90% by mass of an olefin resin consisting of one or more kinds, and (d-2) 10 to 40% by mass of a potassium ionomer having antistatic properties, and (D) The surface resistance of Toshiru layer can be configured to be below 10 ¹² Omega.

  (2) In the present invention, it is preferable that the heat seal layer (D) contains a total of 10% by mass or less of one or both of (d-3) organic fine particles and inorganic fine particles.

(3) In the present invention, the content of isophorone diisocyanate in the pre-curing agent is preferably 4% by mass to 13% by mass based on the total amount of the polyester resin.

(4) In the present invention, the interlayer adhesive strength between the (A) base material layer and the (C) intermediate layer is preferably 5 N / 15 mm or more.

(5) In the present invention, the intermediate layer (C) is composed of a metallocene-based linear low-density polyethylene resin having a density of 0.900 × 10 ³ kg / m ^{3 to} 0.925 × 10 ³ kg / m ³ , and a thickness of Is preferably 15 μm to 25 μm.

(6) In the present invention, the heat-sealing layer (D) is provided with a second heat-sealing layer containing (E) an acrylic resin as a main component on the surface opposite to the (B) intermediate layer side. You can

(6) The present invention is an electronic component package, wherein the cover film according to any one of (1) to (6) is used as a lid material for a carrier tape made of a thermoplastic resin.

  According to the present invention, it is possible to obtain a cover film which has a constant peel strength within a predetermined value range, has excellent transparency, and is less likely to cause "film breakage" during high-speed peeling.

It is sectional drawing which shows an example of the laminated constitution of the cover film of this invention.

  As shown in FIG. 1, the cover film of the present invention includes at least (A) base material layer, (B) adhesive layer, (C) intermediate layer, and (D) heat seal layer. An example of the structure of the cover film of the present invention is shown in FIG. The cover film 1 shown in FIG. 1 includes a base material layer 2, an adhesive material layer 3, an intermediate layer 4, and a heat seal layer 5. In this cover film 1, a base material layer 2, an adhesive layer 3, an intermediate layer 4, and a heat seal layer 5 are laminated in this order.

[(A) Substrate layer]
The (A) substrate layer is a layer made of biaxially oriented polyester or biaxially oriented nylon, and is biaxially oriented polyethylene terephthalate (PET) or biaxially oriented polyethylene naphthalate (PEN), or biaxially oriented 6 , 6-nylon or 6-nylon can be particularly preferably used. As the biaxially stretched PET, the biaxially stretched PEN, the biaxially stretched 6,6-nylon or 6-nylon, an antistatic agent for antistatic treatment is applied or kneaded in addition to the commonly used ones. Those that have been subjected to corona treatment or easy adhesion treatment can be used. If the base material layer is too thin, the tensile strength of the cover film itself will be low, and thus “film breakage” tends to occur when the cover film is peeled off. On the other hand, if it is too thick, not only the heat sealability with respect to the carrier tape is deteriorated but also the cost is increased. Therefore, as the thickness of the base material layer (A), those having a thickness of usually 12 μm to 25 μm can be preferably used.

[(B) Adhesive layer]
The adhesive layer (B) is composed of a cured product of a two-component curable adhesive composed of a main agent and a curing agent, the main agent is a polyester resin, and 50% by mass or more of the curing agent is isophorone diisocyanate. Isophorone diisocyanate is preferably 60% by mass or more. The upper limit is not particularly limited and can be 80% by mass or less, 90% by mass or less, or 100% by mass. When other acrylic resin, olefin resin, or polyether resin is used as the base material, the adhesive strength with the (A) base material layer becomes insufficient.

  Examples of the polyester resin include polyester resins having active hydrogen such as two or more hydroxyl groups or amino groups in the molecule, specifically, polyester polyols and polyester polyamines. The polyester polyol preferably has a hydroxyl value (mgKOH / g) of 1 to 200 and a number average molecular weight of 1,000 to 50,000. The number average molecular weight here is a value measured according to JIS K7252. Examples of the polyester polyol include a condensation reaction product of a polyvalent hydroxyl group-containing compound, a polycarboxylic acid or anhydride, and an ester-forming derivative such as a lower alkyl (alkyl group having 1 to 4 carbon atoms) ester. ..

  The mass fraction of isophorone diisocyanate used as a curing agent is preferably 4 to 13% by mass, more preferably 5% to 10% by mass, based on the total weight of the polyester resin. By setting it to 4% by mass or more, it is possible to prevent the adhesive strength between the (A) base material layer and the (C) intermediate layer from becoming insufficient, and by setting it to 13% by mass or less, while suppressing an increase in cost, It is possible to prevent the material from becoming brittle and lowering the breaking strength.

  When an isocyanate other than isophorone diisocyanate, such as tolylene diisocyanate or xylene diisocyanate, is used alone as a curing agent, the adhesive layer (B) tends to be brittle, and sufficient breaking strength of the film may not be obtained. Further, when diphenylmethane diisocyanate is used as the other curing agent, the curing speed is remarkably faster than that of isophorone diisocyanate used in the present invention, so that coating stability over time is impaired and transparency is lowered. In addition, the adhesive strength between the (A) base material layer and the (C) intermediate layer may be insufficient.

  The two-component curable adhesive is preferably diluted with a solvent and then mixed at a predetermined ratio before use. The diluting solvent is not particularly limited, and water, ethyl acetate, toluene, methyl ethyl ketone, etc. can be used. The adhesive layer (B) is formed by applying the two-component curable adhesive to the base material layer (A) and then drying it. The thickness after drying (that is, the thickness of the adhesive layer (B)) is preferably 1 μm to 5 μm. By setting the thickness to 1 μm or more, it is possible to prevent insufficient adhesion strength due to failure to follow the surface roughness of the intermediate layer (C), and by setting it to 5 μm or less, peel strength after heat sealing to a carrier tape. It is possible to prevent the variation from increasing.

[(C) Intermediate layer]
In the present invention, the intermediate layer (C) is laminated on one surface of the base material layer (A) via the adhesive layer (B). (C) As the resin constituting the intermediate layer, linear low-density polyethylene (hereinafter referred to as LLDPE), which is particularly flexible and has appropriate rigidity and is excellent in tear strength at room temperature, is suitable. By using a resin having a density of 0.900 × 10 ³ kg / m ^{3 to} 0.925 × 10 ³ kg / m ³ , the cover film can be used by heat or pressure during heat sealing. It is difficult for the intermediate layer resin to ooze out from the end. Therefore, not only does the iron on the heat seal become less likely to become dirty, but also the unevenness of the heat seal iron is mitigated by softening the intermediate layer during heat sealing of the cover film, which is stable when the cover film is peeled off. Easy to obtain peel strength.

  The LLDPE includes those polymerized with a Ziegler type catalyst and those polymerized with a metallocene catalyst (hereinafter referred to as m-LLDPE). Since the molecular weight distribution of m-LLDPE is controlled to be narrow, it has a particularly high tear strength, and it is particularly preferable to use m-LLDPE as the intermediate layer (B) of the present invention.

  The m-LLDPE is a copolymer of ethylene with an olefin having 3 or more carbon atoms as a comonomer, preferably a linear, branched or aromatic nucleus-substituted α-olefin having 3 to 18 carbon atoms. Examples of linear monoolefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1 -Octadecene and the like. Examples of branched monoolefins include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene and the like. Moreover, styrene etc. are mentioned as a mono-olefin substituted by the aromatic nucleus. These comonomers can be copolymerized alone or in combination of two or more with ethylene. In this copolymerization, polyenes such as butadiene, isoprene, 1,3-hexadiene, dicyclopentadiene and 5-ethylidene-2-norbornene may be copolymerized.

  The thickness of the intermediate layer (C) is preferably 15 μm to 25 μm, more preferably 15 μm to 20 μm. If the thickness of the intermediate layer (C) is less than 15 μm, it may be difficult to obtain the effect of alleviating unevenness of the heat-sealing iron when the cover film is heat-sealed on the carrier tape. On the other hand, if the thickness exceeds 25 μm, the total thickness of the cover film is large, and it may be difficult to obtain sufficient peel strength when heat sealing the cover film to the carrier tape.

[(D) Heat seal layer]
In the cover film of the present invention, the heat seal layer (D) is formed on the surface of the intermediate layer (C). (D) The resin of the heat seal layer contains (d-1) an olefin resin and (d-2) an antistatic potassium ionomer.

(D-1) Olefin-based resin (d-1) Olefin-styrene block copolymer containing 58 mass% to 82 mass% of olefin component and ethylene-vinyl acetate copolymer containing 75 mass% to 88 mass% of olefin component. The heat seal layer contains at least 50% by mass to 90% by mass of an olefin resin composed of one or more of the above.

  The olefin-styrene block copolymer, styrene-butadiene block copolymer hydrogenated product, styrene-isoprene block copolymer hydrogenated product, styrene-butadiene-styrene block copolymer hydrogenated product, styrene- Examples thereof include hydrogenated products of isoprene-styrene copolymer resin, and one or more selected from these can be used. Among them, a hydrogenated product of styrene-butadiene-styrene block copolymer or ethylene-vinyl acetate is excellent in heat sealability with a carrier tape composed of polystyrene, polycarbonate, polyethylene terephthalate, etc. at the time of heat sealing. Moreover, since it is difficult to cause film breakage, it can be particularly preferably used.

  In the hydrogenated product of the olefin-styrene block copolymer, the preferable content ratio of the olefin component is 58% by mass to 70% by mass. If the olefin component is less than 58% by mass, the content of styrene is large and the heat seal layer (D) becomes hard, so that the variation in peel strength tends to be large, and if it exceeds 82% by mass, the heat sealability is high. It tends to be insufficient.

  In the ethylene-vinyl acetate copolymer, the preferable olefin component ratio is 75% by mass to 84% by mass. When the olefin component is less than 75% by mass, the adhesiveness of the heat-sealing layer (D) becomes strong due to the large content of vinyl acetate, so that when exposed to a high temperature environment, the carrier tape is exposed at a place other than the heat-sealing portion. May adhere to the surface. If it exceeds 88% by mass, the heat sealability tends to be insufficient. The olefin-styrene block copolymer and the ethylene-vinyl acetate copolymer may be used in combination.

  (D) In the olefin resin constituting the heat seal layer, the preferable addition amount is 50% by mass to 70% by mass. If it is less than 50% by mass, the heat-sealing performance is insufficient, and if it exceeds 90% by mass, the tackiness of the (D) heat-sealing layer becomes strong. Adhesion to the carrier tape may occur.

(D-2) Antistatic Potassium Ionomer (D) In the heat-sealing layer, (d-2) antistatic potassium ionomer is added in the range of 10% by mass to 40% by mass. As the antistatic potassium ionomer (d-2), a part or all of the carboxyl groups of an ethylene copolymer composed of ethylene and an unsaturated carboxylic acid or, as an optional component, another monomer are neutralized with potassium. And potassium ionomers. These give a sufficient antistatic property to the outermost surface of the cover film on the side of the (D) heat seal layer, specifically, the atmospheric temperature is 23 ° C. and the atmospheric humidity is 30% R.V. H. The surface resistance value of the heat-sealing layer is 10 ¹² Ω or less, preferably 10 ¹¹ Ω or less.

  Examples of the unsaturated carboxylic acid in the antistatic potassium ionomer include acrylic acid, methacrylic acid, maleic anhydride, monoethyl maleate, etc., although they may vary depending on other additives contained in the heat seal layer. it can. Among these, acrylic acid or methacrylic acid is particularly preferable from the viewpoint of copolymerizability with ethylene. Further, as the above-mentioned other monomer that can be a copolymerization component, the above-mentioned vinyl ester and unsaturated carboxylic acid ester can be mentioned as typical examples. Such other monomer is contained in the above-mentioned copolymer in a proportion of, for example, 0 to 30% by mass.

The antistatic potassium ionomer is contained in the heat seal layer (D) in an amount of 10% by mass to 40% by mass. The preferable addition amount is 10% by mass to 30% by mass. If this component is less than 10% by mass, it is difficult to make the surface resistance value of the (D) heat-sealing layer 10 ¹² Ω or less, and if it exceeds 40% by mass, the heat-sealing property of the cover film deteriorates, which is sufficient. The peel strength may not be obtained.

(D-3) Fine particles (D) In the heat-sealing layer, in order to prevent blocking when the cover film is wound, (d-3) fine particles composed of one or more of organic fine particles and inorganic fine particles ( Hereinafter, it may simply contain (d-3) fine particles. (D-3) The fine particles include organic fine particles such as spherical or crushed acrylic particles, styrene particles, and silicone particles, and inorganic particles such as talc particles, silica particles, mica particles, calcium carbonate, and magnesium carbonate. Fine particles can be added. In particular, acrylic particles and silica particles are less likely to cause a decrease in transparency when added, and can be used more preferably.

(D-3) The maximum frequency diameter obtained from the mass distribution curve of fine particles is preferably 1 μm to 10 μm, more preferably 2 μm to 7 μm. If the maximum frequency diameter is less than 1 μm, the effect of preventing particle blocking may not be sufficiently exhibited. On the other hand, when it exceeds 10 μm, the effect of preventing blocking becomes good, but a large amount is added to prevent blocking, which causes an increase in cost and is visible on the heat-sealing layer surface of the cover film. Since the unevenness may occur, the appearance of the cover film may be impaired.
The maximum frequency diameter according to the mass distribution curve means the maximum frequency diameter obtained by a laser diffraction / scattering method, for example, "LS13320" manufactured by Beckman Coulter.

  The total content of the (d-3) fine particles in the heat seal layer (D) is preferably 10% by mass or less, and more preferably 5% by mass to 10% by mass. When the added amount is 10% by mass or less, the transparency, the heat-sealing property and the blocking prevention effect can be balanced.

  The thickness of the heat seal layer (D) is preferably 5 μm to 40 μm, more preferably 7 to 20 μm. If the thickness of the heat-sealing layer is less than 5 μm, sufficient peeling strength cannot be obtained when heat-sealed with the carrier tape, and the film may be broken. When it exceeds 40 μm, not only the cost is increased, but also the transparency tends to be lowered.

[(E) Second heat seal layer]
In the cover film of the present invention, a second heat seal layer (E) can be formed on the outermost surface of the heat seal layer (D) located on the opposite surface of the intermediate layer (C), if necessary. In other words, the second heat seal layer (E) can be formed on the surface of the heat seal layer (D) opposite to the intermediate layer side (B).

  (E) The second heat seal layer is made of a thermoplastic resin. The thermoplastic resin is not particularly limited, but a thermoplastic resin containing an acrylic resin as a main component is extremely excellent in heat sealability with respect to materials such as polystyrene and polycarbonate constituting the carrier tape. preferable. In particular, the glass transition temperature of the acrylic resin is preferably 45 ° C to 80 ° C, more preferably 50 ° C to 80 ° C. The “main component” means that the content of the acrylic resin in the thermoplastic resin is 30% by mass or more, preferably 50% by mass or more. Further, E) the second heat seal layer may be a layer made of an acrylic resin.

  (E) Examples of the acrylic resin forming the second heat seal layer include acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate. , A methacrylic acid ester such as butyl methacrylate and cyclohexyl methacrylate, and the like, which is a resin containing 50% by mass or more of at least one or more (meth) acrylate components, and may be a resin obtained by copolymerizing two or more of these.

  (E) The thickness of the second heat seal layer is preferably 0.1 μm to 5 μm, more preferably 0.1 μm to 3 μm, and further preferably 0.1 μm to 0.5 μm. When the thickness of the heat seal is 0.1 μm or more, the (E) second heat seal layer exhibits more sufficient peel strength. On the other hand, when the thickness of the heat seal layer is 5 μm or less, the increase in cost is suppressed and variation in peel strength when peeling the cover film hardly occurs.

  Further, (E) the second heat-sealing layer may contain an inorganic filler for the purpose of preventing blocking and imparting antistatic performance. The inorganic filler is not particularly limited, but can contain, for example, at least one of conductive tin oxide particles, conductive zinc oxide particles, and conductive titanium oxide particles. Among them, the use of tin oxide doped with antimony, phosphorus, or gallium improves conductivity and causes less decrease in transparency, and thus can be more preferably used. As the conductive tin oxide particles, conductive zinc oxide particles, and conductive titanium oxide particles, spherical or needle-like particles can be used. In particular, when needle-shaped tin oxide doped with antimony is used, a cover film having particularly good antistatic performance can be obtained.

(E) The mass fraction of the inorganic filler in the second heat-sealing layer is 50% by mass to 90% by mass, and preferably 65% by mass to 90% by mass. If the amount of conductive particles added is less than 50% by mass, the surface resistance of the cover film on the side of the (D) heat seal layer may not be 10 ¹² Ω or less, and if it exceeds 90% by mass, Since the relative amount of the thermoplastic resin decreases, it may be difficult to obtain sufficient peel strength by heat sealing.

[Cover film manufacturing method]
The method for producing the cover film is not particularly limited, and a general method can be used. For example, a two-component curable adhesive composed of a polyester resin and isophorone diisocyanate is applied to the surface of the biaxially stretched polyester film of the base layer (A) to form the adhesive layer (B) and then the intermediate layer (C). A resin composition containing m-LLDPE as a main layer is extruded from a T-die and coated on the coated surface of the adhesive layer (B) to form a layer composed of (A) a base layer and (C) an intermediate layer. The layer film is formed and the adhesive is cured. Further, the target cover film can be obtained by coating the surface of the intermediate layer (C) with the heat seal layer resin (D) extruded from the T die.

  As another method, the films constituting the (C) intermediate layer and the (D) heat-sealing layer are each formed into a film by a T die casting method, an inflation method, or the like, and (A) a biaxially stretched PET film, It is also possible to obtain the target cover film by a dry laminating method in which the respective films are bonded via a two-component curing type adhesive layer composed of a polyester resin and isophorone diisocyanate.

  As another method, the target cover film can be obtained also by the sand laminating method. That is, the film constituting (D) the heat-sealing layer is formed by the T die casting method or the inflation method. Next, a resin composition containing melted m-LLDPE as a main component is supplied between the (D) heat seal layer film and the (A) base layer film to form (C) an intermediate layer and laminate the layers. A method of obtaining a target cover film. Also in the case of this method, as in the case of the above-mentioned method, the one in which the surface of the base material layer film (A) to be laminated is coated with a two-component curable adhesive composed of a polyester resin and isophorone diisocyanate is used.

  In particular, in the cover film of the present invention, (C) the resin composition containing m-LLDPE as the main component, which is the intermediate layer, and (D) the heat seal layer resin are subjected to a T-die casting method using a multi-manifold or a feed block. Alternatively, it is laminated by coextrusion by an inflation method or the like, and the two-layer film is laminated by extrusion lamination onto a PET film coated with a two-component curing type adhesive layer consisting of polyester resin and isophorone diisocyanate to form a cover film. Preferably obtained. Furthermore, it is more preferable to laminate this two-layer film on a PET film coated with a two-component curing type adhesive layer composed of a polyester resin and isophorone diisocyanate by a dry lamination method. In these methods, by co-extruding the (C) intermediate layer with the (D) heat-sealing layer, the adhesive strength between the (C) intermediate layer and the (D) sealant layer becomes stronger, and therefore, during peeling. It is considered that the starting point of the cut of the cover film due to the stress applied to the film is unlikely to occur, and therefore the film breaking strength of the cover film, which is the main subject of the present invention, is further improved.

  In addition to the above steps, at least one surface of the cover film can be subjected to antistatic treatment, if necessary. As the antistatic agent, for example, a surfactant type antistatic agent such as anionic, cationic, nonionic or betaine type, a polymer type antistatic agent, a conductive material dispersed in a binder, or the like is used as a gravure roll. It can be applied by a roll coater, a lip coater, a spray or the like. Further, in order to apply these antistatic agents uniformly, it is preferable to perform corona discharge treatment or ozone treatment on the film surface before performing antistatic treatment, and particularly preferable is corona discharge treatment.

[Electronic parts packaging]
The electronic component package of the present invention is a package in which the above-mentioned cover film is used as a cover material for a carrier tape which is a container for storing electronic components. The carrier tape is a strip having a width of about 8 mm to 100 mm and having a pocket for storing an electronic component. When heat-sealing the cover film as a cover material, the material forming the carrier tape is not particularly limited, and commercially available materials can be used, for example, polystyrene, polyester, polycarbonate, polyvinyl chloride, etc. can be used. You can When an acrylic resin is used for the second heat seal layer, a combination with a carrier tape of polystyrene and polycarbonate is preferably used. The carrier tape is one in which conductivity is imparted by kneading carbon black or carbon nanotubes into a resin, one in which an antistatic agent or conductive filler is kneaded, or a surfactant type antistatic agent or polypyrrole on the surface. It is also possible to use a material obtained by applying an antistatic property by applying a coating liquid in which a conductive material such as polythiophene is dispersed in an organic binder such as acrylic.

  The package containing the electronic component is, for example, after the electronic component is stored in the electronic component storage portion of the carrier tape, the cover film is used as a cover material, and both edges in the longitudinal direction of the cover film are continuously heat-sealed. It is obtained by packaging and winding on a reel. By packaging in this form, electronic components and the like are stored and transported. A package containing electronic components is intermittently peeled off the cover film while being transported using a hole called a sprocket hole for carrier tape transportation, which is provided at the longitudinal edge of the carrier tape. With this, the electronic component is taken out while confirming the existence, orientation, and position of the electronic component and mounted on the substrate.

  Furthermore, when peeling off the cover film, if the peeling strength is too small, it may peel off from the carrier tape, and the stored parts may fall off, and if it is too large, peeling from the carrier tape becomes difficult and the cover film Since there is a risk of breaking during peeling, when heat-sealed at 120 ° C. to 220 ° C., it is preferable that the peel strength is 0.05 N to 1.0 N, and the variation in peel strength is 0. It is preferably less than 4N (less than 0.4N).

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples, the following resin raw materials were used for (A) base material layer, (B) adhesive layer, (C) intermediate layer, and (D) heat seal layer.
(A) Resin of base material layer (a-1) Biaxially stretched polyethylene terephthalate film (o-PET): E-5100 (manufactured by Toyobo Co., Ltd.), thickness 16 μm

(B) Main agent component in the adhesive layer (b-1) Main agent: LIOSTAR1000 (manufactured by Toyo Morton), polyester resin (polyester polyol), ethyl acetate solution, solid content concentration 50% by mass
(B-2) Main agent: LIS-441A (manufactured by Toyo Morton), olefin resin, methyl ethyl ketone solution, solid content concentration 50% by mass
(B-3) Main agent: Seikabond A-159 (manufactured by Dainichiseika Co., Ltd.), polyether resin, ethyl acetate solution, solid content concentration 60 mass%
(B-4) Main agent: N-3495HS (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), acrylic resin, ethyl acetate / toluene / acetone solution, solid content concentration 45 mass%

(B) Curing agent component (b-5) curing agent in the adhesive layer: LIOSTAR500H (manufactured by Toyo Morton), isophorone diisocyanate, ethyl acetate solution, solid content concentration 70% by mass
(B-6) Curing agent: CAT-CT (manufactured by Toyo Morton), diphenylmethane diisocyanate, ethyl acetate solution, solid content concentration 70% by mass
(B-7) Curing agent: CAT-10 (manufactured by Toyo Morton Co., Ltd.), tolylene diisocyanate, ethyl acetate solution, solid content concentration 75 mass%
(B-8) Curing agent: CAT-RT8 (manufactured by Toyo Morton), xylylene diisocyanate, ethyl acetate solution, solid content concentration 75 mass%

(C) Resin (c-1) m-LLDPE for the intermediate layer: Yumerit 2040F (manufactured by Ube Maruzen Polyethylene Co., Ltd.),
MFR 4.0g / 10min (measurement temperature 190 ° C, load 2.16kgf),
Density 0.904 × 10 ³ kg / m ³

(D) Resin for heat-sealing layer (d-1-1) Resin: Tuftec H1041 (manufactured by Asahi Kasei Chemicals Corporation), hydrogenated resin (SEBS) of styrene-butadiene-styrene triblock copolymer, 70% by mass of olefin component
(D-1-2) Resin: Septon 2007 (manufactured by Kuraray Co., Ltd.), hydrogenated resin (SEPS) of styrene-isoprene-styrene triblock copolymer, 70% by mass of olefin component
(D-1-3) Resin: Tuftec H1051 (manufactured by Asahi Kasei Chemicals Corporation), hydrogenated resin (SEBS) of styrene-butadiene-styrene triblock copolymer, 58% by mass of olefin component
(D-1-4) Resin: Tuftec H1062 (manufactured by Asahi Kasei Chemicals Corporation), hydrogenated resin (SEBS) of styrene-butadiene-styrene triblock copolymer, 82% by mass of olefin component
(D-1-5) Resin: Tuftec H1221 (manufactured by Asahi Kasei Chemicals Corporation), hydrogenated resin (SEBS) of styrene-butadiene-styrene triblock copolymer, 88% by mass of olefin component
(D-1-6) Resin: Tuftec H1517 (manufactured by Asahi Kasei Chemicals Corporation), hydrogenated resin (SEBS) of styrene-butadiene-styrene triblock copolymer, 57% by mass of olefin component
(D-1-7) Resin: Tuftec H1043 (manufactured by Asahi Kasei Chemicals Corporation), hydrogenated resin (SEBS) of styrene-butadiene-styrene triblock copolymer, 33% by mass of olefin component

(D-1-8) Resin: Evaflex EV360 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 75% by mass
(D-1-9) Resin: Evaflex EV460 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 81 mass%
(D-1-10) Resin: Evaflex V5714 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 84 mass%
(D-1-11) Resin: Evaflex V421 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 72% by mass
(D-1-12) Resin: Evaflex P1205 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 88 mass%
(D-1-13) Resin: Evaflex EV170 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 67% by mass
(D-1-14) Resin: Evaflex V5711 (manufactured by Mitsui DuPont Polychemical Co., Ltd.), ethylene-vinyl acetate copolymer resin (EVA), olefin component 90% by mass

(D) Antistatic agent in heat-sealing layer (d-2-1) Antistatic agent: Entila MK440 (manufactured by Mitsui-DuPont), potassium ionomer (d-2-2) antistatic agent: Perestat HS (Sanyo Chemical Co., Ltd.) Company), polyetheresteramide (d-2-3) antistatic agent: Erest Master HE-110 (manufactured by Kao Corporation), nonionic surfactant masterbatch (nonionic surfactant 1% by mass, High-density polyethylene 99% by mass)

(D) Fine particles in heat-sealing layer (d-3) Fine particles: PEX-ABT-16 (manufactured by Tokyo Ink Co., Ltd.), talc, silica masterbatch (talc content 5% by mass, silica content 45% by mass, low density polyethylene 50) mass%)

(E) Resin of second heat seal layer (e-1) Resin: NK polymer ECS-706 (manufactured by Shin-Nakamura Chemical Co., Ltd.), styrene-butyl methacrylate random copolymer emulsion, solid content concentration 36% by mass
(E) Conductive filler added to heat seal layer 2
(E-2) Conductive filler: SN-100D (manufactured by Ishihara Sangyo Co., Ltd.), spherical antimony-doped tin oxide, number average major axis 0.1 μm, water dispersion type, solid content concentration 30% by mass.

(Example 1)
50% by mass of styrene-styrene-butadiene-styrene triblock copolymer hydrogenated resin ("Tuftec H1041" manufactured by Asahi Kasei Chemicals Co., Ltd., olefin component content 70% by mass) and styrene as resins constituting the sealant layer (heat seal layer) -Butadiene-styrene triblock copolymer hydrogenated resin (Asahi Kasei Chemicals Corporation, "Tuftec H1043", olefin component amount 33% by weight) 30% by weight, and potassium ionomer (Mitsui DuPont, "MK440") 20% by mass was preblended with a tumbler and kneaded at 200 ° C. using a single screw extruder having a diameter of 40 mm to obtain a resin composition constituting a sealant layer at a line speed of 20 m / min. Separate uniaxial extrusion of this resin composition and metallocene-based linear low-density polyethylene (manufactured by Ube Maruzen Polyethylene Co., Ltd., "Umerit 2040F") as olefin-based resins constituting the intermediate layer (C) in Tables 1 and 2 The film was extruded from the machine and laminated and extruded with a multi-manifold T-die to obtain a two-layer film having a heat seal layer (D) thickness of 10 μm and an intermediate layer (C) thickness of 20 μm. Next, on the bonding surface of the biaxially stretched polyethylene terephthalate film (thickness: 16 μm), a polyester resin (“LIOSTAR1000” manufactured by Toyo Morton Co., Ltd.) as a main component and isophorone diisocyanate (Toyo as a main component) as a curing agent were prepared by a gravure method. Morton Co., Ltd., "LIOSTAR500H") two-component curing type adhesive is mixed in a solid content conversion of 91 (base agent): 9 (curing agent), and the thickness after drying is 3 μm (B) Adhesion An agent layer was formed, and the (C) intermediate layer surface of the two-layer film was laminated by a dry lamination method to obtain a cover film for a carrier tape of an electronic component having the configuration shown in FIG.

(Examples 2-11, Examples 13-24, Examples 26-40, Comparative Examples 1-22)
A cover film was produced in the same manner as in Example 1 except that the adhesive layer and the heat seal layer were formed using the raw materials such as the resins shown in Tables 1 to 5.

(Example 12)
Using the laminated film obtained in Example 4, (D) the surface of the heat-sealing layer was subjected to corona treatment, and then relative to 20% by mass of a styrene-butyl methacrylate random copolymer [(e-1) resin]. [(E-2) Conductive filler] 80% by mass of a solution was applied so that the thickness after drying was 0.3 μm to obtain a carrier tape cover film having conductive performance.

(Example 25)
A cover film was produced in the same manner as in Example 12, except that the laminated film obtained in Example 17 was used.

<Evaluation method>
The following evaluations were performed on the cover films for carrier tapes of electronic parts produced in the respective examples and the comparative examples. The results are summarized in Tables 1 to 5, respectively.

(1) Haze value According to the measuring method A of JIS K 7105: 1998, the haze value was measured using an integrating sphere type measuring device. The results are shown in the haze value column of Tables 1-5.

(2) Sealability Using a taping machine (NK-600, Nagata Seiki Co., Ltd.), seal head width 0.5 mm × 2, seal head length 24 mm, seal pressure 0.5 kgf, feed length 12 mm, seal time 0.3 seconds A cover film having a width of 21.5 mm and a carrier film made of polycarbonate having a width of 24 mm (manufactured by Denki Kagaku Kogyo) and polystyrene carrier tape (Denki Kagaku Kogyo) Product) was heat-sealed. After being left in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50% for 24 hours, the cover film was peeled off at a speed of 300 mm / min and a peeling angle of 170 ° to 180 ° in the atmosphere of a temperature of 23 ° C. and a relative humidity of 50%. .. The sealability was evaluated based on the average peel strength when heat-sealed at 10 ° C intervals from the seal iron temperature of 140 ° C to 190 ° C. The number of samples whose peel strength was measured at each temperature was 3.
"Excellent": The average peel strength was in the range of 0.3 N to 0.9 N at all temperatures.
“Good”: The average peel strength was 1 to 5 points out of the range of 0.3 N to 0.9 N.
"Poor": The average peel strength was out of the range of 0.3 N to 0.9 N at all temperatures. The results are shown in the sealability column of Tables 1-5.

(3) Variation in Peel Strength Heat sealing was performed so that the peel strength of the polystyrene carrier tape (manufactured by Denki Kagaku Kogyo Co., Ltd.) was 0.4N. The cover film was peeled off under the same conditions as in (2) Sealability. The variation in peel strength was derived from the chart obtained when the cover film for 100 mm was peeled in the peeling direction. A peel strength variation of less than 0.2 N was marked as "excellent", a variation of 0.2 N to 0.4 N was marked as "good", and a peel strength variation of more than 0.4 N was marked as "poor". The results are shown in the peel strength variations column of Tables 1-5.

(4) Blocking property Heat sealing was performed under the conditions of (3) so that the peeling strength was 0.4 N, and then a carrier tape was wrapped around a paper tube having a diameter of 95 mm so that the cover film was in the outer peripheral direction. Then, it was left in an environment of 60 ° C. for 24 hours. At this time, those with no adhesive on the flange part of the pocket part (located between them) molded in the carrier tape (to store the electronic parts) are marked as “good”, and those found are marked as “bad” did. The results are shown in the blocking property column of Tables 1-5.

(5) Interlayer adhesion strength After cutting the cover film into a length of 300 mm and a width of 15 mm, the (A) base material layer and the (C) intermediate layer are peeled off in advance, and a tensile tester (EZ Test manufactured by Shimadzu Corporation) is used. The peeled end portions were placed on the plate, and the interlayer adhesion strength was evaluated by T-shaped peeling at a rate of 200 mm / min under the condition of 23 ° C. If the interlayer adhesive strength is less than 5 N / 15 mm, the adhesive strength of 5 N / 15 mm or more may occur because there is a possibility of peeling between the (A) base material layer and the (C) intermediate layer during the electronic component mounting process. Was evaluated as "good", and those having an adhesive strength of less than 5 N / 15 mm were described as "bad". The results are shown in the column of interlayer adhesive strength in Tables 1 to 5.

(6) Breaking resistance of the cover film Heat sealing was performed so that the peel strength with respect to the polystyrene carrier tape (manufactured by Denki Kagaku Kogyo) was 1.0 N. The cover film was peeled off under the same conditions as in (2) Sealability. The carrier tape with the cover film sealed was cut into a length of 550 mm, and at 23 ° C., the bottom of the pocket of the carrier tape was attached to the vertical wall to which the double-sided adhesive tape was attached. The cover film was peeled off by 50 mm from the top of the attached carrier tape, the cover film was sandwiched by clips, and a weight of 1000 g was attached to the clips. After that, when the weight was allowed to fall naturally, even if one of the 50 samples did not have the cover film cut, it was “excellent”, and 1 to 5 samples of the 50 samples had the cover film cut, “good”, 6 samples or more The cut pieces were marked as "bad". The results are shown in the film breakability column of Tables 1 to 5.

(7) Stability of peel strength with time Under the same conditions as in (3) Sealability, heat sealing was performed so that the peel strength was 0.4N. It is put in an environment of temperature 60 ° C, relative humidity 10%, and temperature 60 ° C, relative humidity 95% for 7 days, and after taking out, it is left for 24 hours in an atmosphere of temperature 23 ° C, relative humidity 50%, and the same temperature 23 ° C. The peel strength was measured under an atmosphere of 50% relative humidity. The peel strength was measured under the same conditions as the above (3) Sealability. Those having an average peel strength in the range of 0.3N to 0.5N are defined as "excellent", and those in the range of 0.2N to less than 0.3N and more than 0.5N and 0.6N or less are defined as "good". The average peel strength other than the above was described as “poor”. The results are shown in the sealability column of Tables 1-5.

(8) Surface resistance value The surface resistance value of the surface of the heat-sealing layer was measured at a temperature of 23 ° C., an atmospheric humidity of 50% RH, and an applied voltage of 500 V by the method of JIS K6911 using Hiresta UP MCP-HT450 manufactured by Mitsubishi Chemical Corporation. .. The results are shown in the surface resistance column of Tables 1-5.

  As is clear from Tables 1 to 3, the cover films of Examples 1 to 40 are cover films used in combination with carrier tapes such as polystyrene and polycarbonate, and peeling when peeling the cover film to take out an electronic component. The strength of the cover film is continuously constant within a predetermined range, is excellent in transparency, and does not easily cause "film breakage" during high-speed peeling.

1 Cover Film 2 Base Layer 3 Adhesive Layer 4 Intermediate Layer 5 Heat Seal Layer

Claims (7)

A cover film having at least (A) base material layer, (B) adhesive layer, (C) intermediate layer, and (D) heat-sealing layer,
(A) The base material layer is made of biaxially stretched polyester or biaxially stretched nylon and has a thickness of 12 to 25 μm,
(B) The adhesive layer is composed of a cured product of a main agent containing a polyester resin and a curing agent containing 50% by mass or more of isophorone diisocyanate,
(C) The intermediate layer is made of a linear low-density polyethylene resin having a density of 0.900 × 10 ³ kg / m ^{3 to} 0.925 × 10 ³ kg / m ³ , and a thickness of 15 μm to 25 μm,
(D) The resin forming the heat seal layer is
(D-1) One or both of an olefin-styrene block copolymer containing 58% by mass to 82% by mass of an olefin component and an ethylene-vinyl acetate copolymer containing 75% by mass to 88% by mass of an olefin component are contained. 50% by mass to 90% by mass of olefin resin,
(D-2) 10 mass% to 40 mass% of a potassium ionomer having an antistatic property,
Moreover, the surface resistance value of the outermost surface of the cover film on the side of the heat-sealing layer (D) is 10 ¹² Ω or less.   The cover film according to claim 1, wherein the heat-sealing layer (D) contains a total of 10% by mass or less of one or both of the organic fine particles and the inorganic fine particles (d-3).   The cover film according to claim 1 or 2, wherein the content of isophorone diisocyanate in the curing agent is 4% by mass to 13% by mass based on the total amount with the polyester resin.   The cover film according to any one of claims 1 to 3, wherein the interlayer adhesive strength between the (A) base material layer and the (C) intermediate layer is 5 N / 15 mm or more. (C) The intermediate layer is made of a metallocene linear low-density polyethylene resin having a density of 0.900 × 10 ³ kg / m ^{3 to} 0.925 × 10 ³ kg / m ³ , and a thickness of 15 μm to 25 μm. The cover film according to any one of claims 1 to 4.   The heat-sealing layer (D) has a second heat-sealing layer containing (E) an acrylic resin as a main component on the surface of the heat-sealing layer (B) opposite to the intermediate layer side. The cover film described. An electronic component package using the cover film according to any one of claims 1 to 6 as a cover material for a carrier tape made of a thermoplastic resin.

Images