JP6686167B2 - Surface conductive laminated sheet and electronic component packaging container - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a surface conductive laminated sheet made of a thermoplastic resin, and a carrier tape using the laminated sheet, an electronic component packaging container such as a tray for carrying electronic components.

  Vacuum packaging trays, embossed carrier tapes and the like obtained by heat-forming sheets are used for packaging containers for intermediate products of various industrial products such as electronic devices and automobiles. Then, as a sheet for a packaging container of an IC that dislikes static electricity or various electronic parts having an IC, a sheet obtained by laminating a polystyrene resin containing a conductive filler such as carbon black on a base material layer made of a polystyrene resin is provided. It is used (for example, see Patent Documents 1 to 3).

  In recent years, with the miniaturization of electronic components, when picking up electronic components stored in the embossed part (also called pocket) of the carrier tape and automatically mounting them on the printed circuit board, the pickup nozzle does not contact the carrier tape and the accuracy is improved. It is becoming difficult to pick up electronic parts often. When the pick-up nozzle comes into contact with the carrier tape, the carrier tape is crushed or deformed, which causes a so-called pick-up defect that occurs when the pick-up nozzle obstructs the path of the pick-up.

JP-A-9-76422 JP, 9-76425, A JP, 9-174769, A

  The present invention, for example, in a carrier tape having conductivity, a surface conductive laminated sheet which can suppress crushing and deformation of the carrier tape even when the pickup nozzle comes into contact with the carrier tape during electronic component mounting, and which has excellent strength, and An object of the present invention is to provide an electronic component packaging container formed by molding it, more specifically, a carrier tape or an electronic component transport tray.

  The present inventors, as a result of diligent study on these problems, by containing a polystyrene resin having a conjugated diene content in a specific range in the base layer and the surface layer, a surface conductive laminate that has solved all of the above problems. The inventors have found that a sheet can be obtained, and completed the present invention.

That is, in the present invention, the conjugated diene content is 2.0 to 7.4% by mass on both surfaces of the sheet base material layer made of the polystyrene resin having a conjugated diene content of 3.0 to 8.2% by mass. It is a surface conductive laminated sheet having a Martens hardness of 50 to 130 N / mm ² , in which a surface layer made of a conductive resin composition containing a polystyrene resin and a conductive filler is laminated. The conductive filler is preferably carbon black. When the conductive filler is carbon black, the conductive resin composition of the surface layer preferably further contains a hydrogenated resin of an olefin resin and an aromatic vinyl-conjugated diene block copolymer.

  Further, the surface layer is hydrogenated with a polystyrene-based resin 46 to 85 mass%, carbon black 13 to 23 mass%, an olefinic resin 1.5 to 20 mass%, and an aromatic vinyl-conjugated diene-based block copolymer. It is preferable that the resin contains 0.5 to 11% by mass.

  The volume average particle diameter of the conjugated diene contained in the polystyrene resin used for the base material layer and the surface layer is preferably 0.5 to 4.0 μm.

  Furthermore, the present invention includes an electronic component packaging container formed from the above surface conductive laminated sheet, specifically, a carrier tape or an electronic component transport tray.

  According to the present invention, since the polystyrene-based resin having a conjugated diene content in a specific range is used as the base material layer and the surface layer, for example, in a carrier tape having conductivity, the pick-up nozzle is used as a carrier tape when mounting electronic components. It is possible to obtain a surface conductive laminated sheet which can suppress the crushing and deformation of the carrier tape even if they come into contact with each other and which has practically sufficient strength, and an electronic component packaging container such as a carrier tape using the sheet.

  Hereinafter, modes for carrying out the present invention will be described in detail, but the present invention is not limited to the embodiments including the following examples.

  A surface conductive laminated sheet according to an embodiment of the present invention is composed of a base material layer containing polystyrene (PS) resin as a main component and conductive surface layers laminated on both surfaces of the base material layer. It

  The polystyrene (PS) -based resin means a resin containing polystyrene resin (GPPS), impact-resistant polystyrene resin (rubber-modified styrene resin, HIPS), or a mixture thereof as a main component. Examples of the aromatic vinyl monomer constituting the polystyrene resin include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene. , Vinyl anthracene, 1,1-diphenylethylene and the like. Of these aromatic vinyl monomers, styrene, vinyltoluene, o-methylstyrene, etc., especially styrene, are usually used. The impact-resistant polystyrene resin is a polystyrene resin in which a styrene monomer is graft-polymerized on a rubber-like elastic body containing a conjugated diene as a main component. Examples of the conjugated diene used include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene and 1,3-hexadiene. The most common one is 1,3-butadiene.

  The polystyrene-based resin used for the base layer contains the conjugated diene in an amount of 3.0 to 8.2% by mass, preferably 3.0 to 5.0% by mass, and the polystyrene-based resin used in the surface layer contains 2 of the conjugated diene. 0.0 to 7.4% by mass, preferably 2.0 to 4.0% by mass. By setting the content of the conjugated diene in the polystyrene resin used for the base material layer and the surface layer in the above range, the range of Martens hardness described below can be achieved.

  The content of the conjugated diene in the polystyrene resin is conveniently adjusted by blending GPPS and HIPS, but it may be adjusted at the stage of manufacturing HIPS. Further, the melt flow index (measured according to JIS-K-7210) of GPPS or HIPS used for the base material layer and the surface layer is not particularly limited, but is 1 to 15 g under the conditions of 200 ° C. and a load of 5 kg. / 10 minutes is preferably used in terms of molding processing.

  The content of the polystyrene-based resin in the surface layer is preferably 46 to 85% by mass, more preferably 54 to 81% by mass, and further preferably 58 to 80% by mass. When the content is 85 mass% or less, a decrease in conductivity due to a decrease in the addition amount ratio of the conductive filler is suppressed, and when the content is 46 mass% or more, a decrease in tensile elastic modulus is suppressed.

  The volume average particle size of the conjugated diene contained in the polystyrene resin used for the base material layer and the surface layer is preferably 0.5 to 4.0 μm, and more preferably 2.0 to 3.5 μm. 2.4 to 3.0 μm is more preferable. Good mechanical performance can be obtained when the volume average particle diameter is within the above range. When the volume average particle diameter is 4.0 μm or less, the tensile elastic modulus is suppressed from decreasing, and when it is 0.5 μm or more, the folding endurance is suppressed from decreasing.

  The conductive filler contained in the surface layer is not particularly limited, but carbon black is particularly preferable from the viewpoint of moldability and the like. Carbon black is furnace black, channel black, acetylene black or the like, and preferably acetylene black is particularly preferable from the viewpoint that it has a large specific surface area and a high conductivity can be obtained with a small amount added to the resin. The amount added to the surface layer is preferably 13 to 23% by mass, more preferably 16 to 21% by mass. A content of 13% by mass or more provides a sufficient surface resistance value, and a content of 23% by mass or less suppresses the fluidity and the mechanical strength of the obtained sheet.

  The olefin resin may be added in order to prevent the desorption of carbon black in a resin composition consisting of polystyrene resin and carbon black, since desorption of carbon black may occur. The amount added to the surface layer is preferably 1.5 to 20% by mass, more preferably 2.5 to 18% by mass. When the addition amount is 1.5% by mass or more, the effect is obtained, and when the addition amount is 20% by mass or less, it becomes easy to uniformly disperse in the obtained polystyrene resin composition. By using the resin composition in which the olefin resin is uniformly dispersed, desorption of carbon from the produced sheet is less likely to occur. In addition, it is possible to suppress a decrease in the tensile elastic modulus of the produced sheet and a decrease in the strength of the pocket of the molded electronic component packaging container.

  Examples of the olefin-based resin include polyethylene resins such as high-density polyethylene, ultra-low-density polyethylene and linear low-density polyethylene, polypropylene, and C3 or higher α-olefin hydrocarbons such as propylene, 1-butene, and 1-hexene. Examples thereof include copolymerized ethylene-α olefin copolymers. Further, not only olefins but also copolymers with monomers having a polar group capable of copolymerizing with olefins are included. Examples of such resins include ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl acetate-vinyl chloride copolymer. And ternary copolymers with acid anhydride and the like. These olefin resins can be used alone or in combination with other olefin resins.

  The hydrogenated resin of the aromatic vinyl-conjugated diene block copolymer can be added to serve as a compatibilizing agent for uniformly mixing the polystyrene resin and the polyolefin resin. When the conductive resin composition of the surface layer contains a polystyrene resin and a polyolefin resin, the addition amount of the hydrogenated resin of the aromatic vinyl-conjugated diene block copolymer in the conductive resin composition of the surface layer is The amount is preferably 0.5 to 11% by mass, more preferably 0.5 to 7% by mass. When the addition amount is 0.5% by mass or more, the effect is obtained, and when the addition amount is 11% by mass or less, it is easy to uniformly disperse in the obtained polystyrene resin composition. When the resin composition in which the hydrogenated resin of the aromatic vinyl-conjugated diene block copolymer is uniformly dispersed is used, carbon black is less likely to be detached from the produced sheet. In addition, a decrease in tensile modulus of elasticity of the produced sheet and a decrease in rigidity of the molded electronic component packaging container are suppressed.

  As the hydrogenated resin of the aromatic vinyl-conjugated diene block copolymer, typically, a hydrogenated resin of a styrene-butadiene block copolymer, a hydrogenated resin of a styrene-isoprene block copolymer and the like can be mentioned. Among them, hydrogenated resin of styrene-butadiene block copolymer, that is, SEBS (styrene-ethylene-butylene-styrene block copolymer) and SBBS (styrene-butadiene-butylene-styrene block copolymer) are particularly preferably used. .

  SEBS is, for example, a styrene-butadiene block copolymer having a structure of styrene block-butadiene block-styrene block, styrene block- (butadiene-styrene random block) -styrene block, butadiene block-styrene block-butadiene block-styrene block, and the like. And SBBS are obtained by selectively hydrogenating a specific part of butadiene. The production method is not particularly limited, but it is disclosed in JP-A-64-38402, JP-A-60-220147, JP-A-61-33132, JP-A-61-28507, JP-A-61-57524 and the like. It has been reported and a commercially available product can be used as it is.

  The base material layer and the surface layer may contain various kinds of lubricants, plasticizers, heat stabilizers, processing aids, inorganic fillers, matting agents, etc., if necessary, within a range that does not impair the properties required for the purpose of the present invention. It is possible to add additives.

The surface resistivity of the surface layer of the surface-conductive laminated sheet is preferably 10 ² to 10 ¹⁰ Ω / □, 10 ³ to 10 ⁹ Ω / □, or 10 ⁴ to 10 ⁷ Ω / □. By setting the surface resistivity to 10 ¹⁰ Ω / □, it is possible to suppress the destruction of electronic parts due to static electricity, and by setting the surface resistivity to 10 ² Ω / □ or more, it is difficult for electricity to flow from outside due to static electricity or the like. Therefore, it is possible to prevent the electronic parts from being destroyed.

The Martens hardness of the surface conductive laminated sheet may be 50 to 130 N / mm ² , 65 to 120 N / mm ² , or 70 to 120 N / mm ² . By setting the Martens hardness to 130 N / mm ² or less, reduction in folding strength can be suppressed, and by setting it to 50 N / mm ² or more, it becomes easy to suppress crushing and deformation of the sheet.
The tensile elastic modulus of the surface conductive laminated sheet may be 1600 to 2200 MPa, 1650 to 2100 MPa, or 1650 to 2000 MPa.
Further, the folding resistance of the surface conductive laminated sheet may be at least 50 times, at least 400 times, at least 600 times, at least 800 times, or at least 1000 times.

  The total thickness of the surface conductive laminated sheet is generally 0.1 to 3.0 mm from its application, and the thickness of the surface layer in the total thickness is preferably 2 to 80%, and 5 to 60%. Is particularly preferable. When the total thickness is 0.1 mm or more, a certain strength can be obtained even when it is molded into a packaging container, and when it is 3.0 mm or less, molding such as pressure molding, vacuum molding, hot plate molding is easy. Becomes Further, when the thickness of the surface layer is 2% or more, when molded into a packaging container, the surface resistivity is suppressed from significantly increasing, and a sufficient static electricity suppressing effect is obtained. It is possible to suppress deterioration of formability such as vacuum forming and hot plate forming.

  The method for producing the surface conductive laminated sheet is not particularly limited. For example, the raw materials for the base material layer and the surface layer are uniformly mixed by a high-speed mixer, or further kneaded and pelletized by a known method using an extruder or the like, and then the mixture is formed by a known method using an extruder or the like. The surface conductive laminated sheet in one embodiment of the invention can be used.

  As a method of laminating the surface layer on the base material layer, it is also possible to form each into a sheet or film by a separate extruder and then laminate the layers stepwise by a heat laminating method, a dry laminating method, an extrusion laminating method or the like. Alternatively, it is also possible to laminate the resin composition to be the surface layer on both sides of the preformed base material layer sheet by a method such as extrusion coating, but in order to produce at a lower cost, a multi-manifold die It is preferable to obtain a laminated sheet at once by a multi-layer coextrusion method using a feed block. In addition, in the method for manufacturing a laminated sheet of this type, it is general to crush scrap resin generated in the manufacturing process of the sheet or the molding container and recycle it to the base material layer, and the surface conductivity in one embodiment of the present invention. Also in the laminated sheet, the scrap resin can be mixed with the base material layer within a range that does not significantly affect the strength reduction and the occurrence of burrs when slitting or the like.

  The surface conductive laminated sheet can be formed into a shape according to the application by a known thermoforming method such as a vacuum forming method, a pressure forming method and a press forming method.

  The surface conductive laminated sheet is used as a material for a semiconductor such as an IC, a packaging container for electronic parts using the IC, a vacuum forming tray, a magazine, an embossed carrier tape, and an electronic part housed in the embossed carrier tape, and the top surface thereof is covered. The tape can be heat-sealed for use in an electronic component packaging body and the like, and particularly preferably used for an embossed carrier tape.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Evaluation methods]
Each evaluation was performed by the following method by sampling in the sheet extrusion direction.
(1) Martens hardness Based on ISO14577, about a sheet sample, arbitrary 5 points on the surface were measured using Nano Indenter G200 by Toyo Technica, and the average value was made into the Martens hardness. At this time, the measurement was performed at an approach speed of the indenter of 500 nm / s and a maximum test load of 5 mN.
(2) Tensile Elastic Modulus The sheet sample was measured with a test piece type 5 using Strograph VE-1D manufactured by Toyo Seiki Seisakusho in accordance with JIS-K-7127.
(3) Folding strength A sheet sample was made into a test piece with a length of 150 mm, a width of 15 mm, and a thickness of 0.2 mm in accordance with JIS-P-8115 (2001), and a MIT folding fatigue test manufactured by Toyo Seiki Seisakusho. The MIT folding endurance strength was measured using a machine. At this time, the test was conducted at a bending angle of 135 degrees, a bending speed of 175 times per minute, and a measurement load of 250 g.
(4) Surface resistance value It measured using Mitsubishi Chemical Analytech company Hiresta-UX (MCP-HT800).
(5) conjugated diene content of the conjugated diene content impact in polystyrene is an infrared absorption spectrum method which is generally used in rubber-modified polystyrene, 960 cm ^-1, was determined by measuring the absorbance at 910 cm ^-1 .
(6) Volume average particle diameter The volume average particle diameter of the dispersed particles was measured by dissolving 0.5 g of impact-resistant polystyrene in 100 g of dimethylformamide and using a Coulter Counter (LS-230) manufactured by Nikkaki Co., Ltd.

  Table 1 shows the polystyrene resins used in Examples and Comparative Examples.

(Example 1)
As the carbon black, acetylene black particles manufactured by Denka Co. were used.
As an olefin resin, ethylene-ethyl acrylate copolymer resin (hereinafter referred to as EEA) has an ethyl acrylate content (measured according to JIS-K-7192) = 18%, melt flow index (JIS-K-7192). (Measurement according to the above) = 5.0 g / 10 min. A high-density polyethylene resin (hereinafter referred to as HDPE) having a melt flow index (measured according to JIS-K-6922-2) = 0.20 g / 10 min was used.
As a hydrogenated resin of an aromatic vinyl-conjugated diene block copolymer, a styrene-ethylene-butylene-styrene block copolymer (hereinafter referred to as SEBS) has a melt flow index (measured according to JIS-K-7192) = The amount used was 4.0 g / 10 minutes, and the mass% ratio of styrene and butadiene was 60:40.
For the surface layer, as shown in Table 2, polystyrene resin and impact-resistant polystyrene resin A, carbon black, EEA, HDPE, and SEBS were weighed in a ratio of 29: 31: 20: 9: 8: 3, respectively. After uniformly mixing with a high-speed mixer, the mixture was kneaded with a φ45 mm bent type twin-screw extruder and pelletized by a strand cut method to obtain a conductive resin composition.
On the other hand, for the base material layer, as shown in Table 2, the polystyrene resin and the impact-resistant polystyrene resin B were weighed out in a ratio of 43:57, and a uniform mixture was obtained by a high-speed mixer.
For the base material layer, the pelletized conductive resin composition and a uniform mixture of the polystyrene resin and the high impact polystyrene resin B are used so that the surface layers have substantially the same thickness on both surfaces of the base material layer. As a φ65 mm extruder (L / D = 28), as a surface layer using a φ40 mm extruder (L / D = 26), and a 500 mm-wide T-die as a feed block method. A surface-conductive laminated sheet having a ratio of 1: 18: 1 and a total thickness of 0.2 mm was obtained.

(Examples 2 to 13, Comparative Examples 1 to 4)
According to the method of Example 1, a surface conductive laminated sheet was obtained. Tables 2 and 3 show each raw material and the mixing ratio thereof.

  The evaluation results of the sheets prepared in the respective examples and comparative examples are shown in Tables 2 and 3.

  From the results shown in Tables 2 and 3, the following things became clear. Surface conductive laminated sheet of each example, as a sheet for packaging various electronic components, while ensuring practically sufficient tensile elastic modulus, folding strength and surface resistivity, also high Martens hardness, these sheets, It was confirmed that the carrier tape obtained by molding was not crushed or deformed even when the pickup nozzle came into contact with it. On the other hand, the surface conductive laminated sheets of Comparative Examples 1 and 3 have too high Martens hardness and low folding endurance, and the surface conductive laminated sheets of Comparative Examples 2 and 4 have too low Martens hardness. It was confirmed that the carrier tape obtained by molding the sheet was crushed or deformed by contact with the pickup nozzle.

Claims (7)

Polystyrene resin having a conjugated diene content of 2.0 to 7.4% by mass on both sides of a sheet base material layer made of a polystyrene resin having a conjugated diene content of 3.0 to 8.2% by mass, and A surface conductive laminated sheet in which a surface layer made of a conductive resin composition containing a conductive filler is laminated and has a Martens hardness of 50 to 130 N / mm ² .   The surface conductive laminated sheet according to claim 1, wherein the conductive filler is carbon black.   The surface conductive laminated sheet according to claim 2, wherein the conductive resin composition of the surface layer further contains an olefin resin and a hydrogenated resin of an aromatic vinyl-conjugated diene block copolymer.   The surface layer comprises polystyrene resin 46 to 85% by mass, carbon black 13 to 23% by mass, olefin resin 1.5 to 20% by mass, and hydrogenated resin 0 of aromatic vinyl-conjugated diene block copolymer. The surface conductive laminated sheet according to claim 3, wherein the surface conductive laminated sheet contains 0.5 to 11% by mass.   The surface conductive laminated sheet according to any one of claims 1 to 4, wherein the conjugated diene contained in the polystyrene resin used for the base material layer and the surface layer has a volume average particle diameter of 0.5 to 4.0 µm. .   An electronic component packaging container formed from the surface conductive laminated sheet according to claim 1.   The electronic component packaging container according to claim 6, which is a carrier tape or a tray for transporting electronic components.