JPH11105181A - Cover tape for packing electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cover tape from being broken when it is peeled off by specifying respectively draw ratio in the longitudinal direction and in the transverse direction of the base layer of the cover tape, and preparing it of a monoaxially strongly drawn plastic film with specified draw ratios in the longitudinal direction and the transverse direction and a heat sealant layer. SOLUTION: A cover tape is constituted by providing a monoaxially strongly drawn plastic film wherein the draw ratio of the base layer 1 of the cover tape is 2-8-fold in the longitudinal direction and 1-3-fold in the transverse direction and the draw ratio in the longitudinal direction is at least 2-fold of the draw ratio in the transverse direction and if necessary, a heat sealant layer 4 through an intermediate layer 5. The plastic used for the monoaxially strongly drawn film is selected from polyethylene terephthalate, nylon 6, polypropylene, polycarbonate, polyimide, etc. As a method for drawing the film, monoaxial drawing in the transverse or longitudinal direction, successive biaxial drawing, simultaneous biaxial drawing, etc., can be applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin container for accommodating various industrial parts, for example, a semiconductor device is accommodated in a pocket of a concave portion formed continuously in a carrier tape, and the accommodating portion is covered and heat sealed. A cover tape for a carrier tape belongs to a cover tape that does not break and can be easily peeled off when mounted on a small electronic component.

[0002]

2. Description of the Related Art Heretofore, a carrier tape which has been filled with electronic components and heat-sealed has been used as a cover tape comprising a base layer made of a biaxially stretched plastic film mainly composed of a biaxially stretched polyester film, and a carrier tape. And a heat sealant layer which can be easily peeled off. An intermediate layer (cushion layer) is provided between the base material layer and the heat sealant layer so that the pressure of the heat seal can be uniformly adjusted, or the heat sealant layer of the cover tape heat-sealed with the carrier tape is provided. It was constituted by providing an intermediate layer (peeling strength adjusting layer) for adjusting the peeling strength with the substrate layer. In addition, when mounting electronic components from a carrier tape or in order to prevent destruction of electronic components due to static electricity generated during transport, blend or apply an antistatic agent to the carrier tape or cover tape. Had been used. Each layer of the cover tape has been laminated and formed by providing an adhesive or an adhesive resin layer via a primer layer as necessary. The heat sealant layer also has a relationship with the material of the heat sealing surface of the carrier tape, but heat sealants made of thermoplastic resin such as vinyl chloride / vinyl acetate copolymer, polyurethane, polyester resin, ethylene / vinyl acetate copolymer, etc. A sealant is provided by coating, or a monolayer film or a co-extruded multilayer film is laminated on a base sheet to form a cover sheet.

In recent years, the technology for surface mounting on printed circuit boards has been improved, and electronic components have been reduced in size. As a result, the width of the carrier tape has become narrower, and accordingly the width of the cover tape has also become narrower. Along with this, the cover tape is also peeled off at a higher speed than before and electronic components are mounted,
There has been a problem that the cover tape is broken.

[0004]

SUMMARY OF THE INVENTION In order to prevent breakage of the cover tape, which is generated when the electronic component is mounted by peeling the narrow cover tape from the carrier tape on which the small electronic component is mounted, a base layer is provided. And the use of a substrate layer in which a biaxially oriented polyester film and a biaxially oriented nylon film are laminated. However, in the cover tape heat-sealed to the carrier tape, the end (heat-sealed portion) is deteriorated by heat and pressure, and the strength (tensile rupture strength, tear strength) of the base material layer itself is reduced. Further, it is presumed that the cover tape is broken in the mounting process due to a shift due to a difference in the degree of expansion and contraction between the carrier tape and the cover tape after heat sealing, and an increase or change in peel strength.
In particular, the conventionally used biaxially stretched plastic film has a problem that even when a very slight scratch is generated at the end portion, the film is likely to be torn due to the scratch and to break the film.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cover tape which comprises at least a base material layer and a heat sealant layer, and which can be heat-sealed to a carrier tape containing electronic components in recesses. The longitudinal stretching ratio of the base layer of the cover tape is 2 to 8 times,
Further, an electronic component packaging comprising a plastic film stretched strongly in a uniaxial direction having a stretch ratio in the transverse direction of 1 to 3 times and a stretch ratio in the longitudinal direction of at least 2 times the stretch ratio in the transverse direction, and a heat sealant layer. Cover tape. Also,
In the above cover tape, the stretching ratio in the longitudinal direction of the base material layer is 2 to 8 times, and the stretching ratio in the transverse direction is 1 to 3 times.
And a stretch ratio in the longitudinal direction is 1 to 3 times, and the stretch ratio in the longitudinal direction is 1 to 3 times, and the stretch ratio in the transverse direction is 1 to 3 times. And a heat sealant layer comprising a laminate of a plastic film strongly stretched in the transverse direction having a stretch ratio of 2 to 8 times and a stretch ratio in the longitudinal direction of 以下 or less of the stretch ratio in the transverse direction, and a heat sealant layer. It is a tape.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The cover tape 10 of the present invention is different from the cover tape 10 shown in FIG. 1 in that the stretch ratio of the base layer 1 of the cover tape in the longitudinal direction is 2 to 8 times.
The stretching ratio in the transverse direction is 1 to 3 times, and the stretching ratio in the longitudinal direction is 2 times or more the stretching ratio in the transverse direction. It is configured by providing a sealant layer 4. Further, in the cover tape 10 shown in FIG. 2, the stretching ratio in the vertical direction is 2 to 8 times, the stretching ratio in the horizontal direction is 1 to 3 times, and the stretching ratio in the vertical direction is A plastic film substrate layer 1A strongly stretched in a uniaxial direction at least twice the stretching ratio, and a stretching ratio in the longitudinal direction of 1 to 3;
And a base layer 1B made of a plastic film stretched in the transverse direction, wherein the stretch ratio in the transverse direction is 2 to 8 times, and the stretch ratio in the longitudinal direction is 以下 or less of the stretch ratio in the transverse direction. The intermediate layer 5 may be added to the base material layer 1 which is a laminate of
And a heat sealant layer 4 is provided through the intermediary.

[0007] The base material layer is required to have excellent transparency, dimensional stability, thermal stability, tensile strength, tear strength and the like. Usually, it is a stretched film of a thermoplastic resin having relatively excellent heat resistance. The film used as the substrate layer of the present invention is a film which is strongly stretched in a uniaxial direction. The plastic (thermoplastic resin) used is a polyester such as polyethylene terephthalate, a polyamide such as nylon 6 or nylon 66, or a polyolefin such as polypropylene. , Polycarbonate, polyimide and the like.

In the production of a film to be a base material layer, a thermoplastic resin as a raw material is melt-extruded by an extruder provided with a T-die to form a film, which is cooled and solidified by a cooling roll. Next, in a stretching step, the film is stretched in a longitudinal direction and / or a transverse direction at a predetermined stretching ratio. Further, in order to fix crystallization and molecular orientation, both ends of the film are held and heat fixing is performed at a temperature lower than the melting point under a constant tension condition.

As the stretching method of the film, known (horizontal or vertical) uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching and the like can be applied. The stretching device can be appropriately selected from a two-roll type vertical uniaxial stretching machine, a tenter type horizontal stretching machine, a tenter type or a tubular simultaneous biaxial stretching machine and the like. Then, using a tenter type or tubular type simultaneous biaxial stretching machine, the longitudinal stretching ratio is 2 to 8 times, and the transverse stretching ratio is 1 to 3 times. In addition, a plastic film to be a base material layer is formed by one layer which is strongly stretched in a uniaxial direction and has a stretching ratio in a longitudinal direction of 2 times or more as large as a stretching ratio in a transverse direction. Further, using a tenter type, or a simultaneous biaxial stretching machine of a tubular type, the stretching ratio in the transverse direction in which the transverse direction is strongly stretched is 2 to 8 times, and the stretching ratio in the longitudinal direction is 1 to 3 times, In addition, a plastic film that has been strongly stretched in a uniaxial direction with a stretching ratio in the transverse direction of at least twice the stretching ratio in the longitudinal direction is formed.

A base layer 1 for laminating a longitudinally uniaxially stretched film 1A and a laterally uniaxially stretched film 1B shown in FIG. 2 is dry-laminated through an adhesive layer 2, or not shown in the drawing. Each of the uniaxially stretched transversely oriented films is provided with a primer layer as necessary, and laminated by sandwich lamination with an adhesive resin layer. Then, the heat sealant layer is provided on any arbitrary surface of the horizontal uniaxially stretched film 1B or the vertical uniaxially stretched film 1A. Although not shown, an intermediate layer 5 such as a cushion layer can be provided between the vertically uniaxially stretched film 1A and the horizontally uniaxially stretched film 1B. By selecting the type and thickness of the adhesive layer 2 and the adhesive resin layer 3, the intermediate layer 5 can have a desired function.

The main components of the two-component reactive or thermosetting adhesive layer used for dry lamination when forming the two-layer substrate layer 1 of the present invention are polyester-based resins, polyether-based resins, and urethanes. Resin, urethane modified polyester resin, urethane polyether resin, vinyl copolymer, ethylene / vinyl acetate resin, ethylene / vinyl acetate / acrylic resin, acrylic resin, aromatic polyamine resin, polythiol Resin, ethylene
It is mainly composed of acrylic resin, epoxy resin, polyamide, various synthetic rubbers and the like. As the curing agent, tolylene diisocyanate, 4,4 ^, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, naphthylene-1,5 diisocyanate, polyamine, polythiol, etc., differ depending on the type, but 100 parts by weight of the main agent Is mixed in an amount of 1 to 100 parts by weight.

Further, an ionizing radiation curable resin can be used for the adhesive layer. For example, a prepolymer, oligomer, and / or a polymer having a polymerizable unsaturated bond or an epoxy group in a molecule.
Alternatively, a composition in which monomers are appropriately mixed is used. For example, there are urethane acrylate and polyester acrylate.

The method of applying the adhesive layer is not limited to gravure coating, roll coating and the like. The thickness (coating amount) of the reaction-curable adhesive layer is
This is a factor that gives the cover tape rigidity. The coating amount is ^{2 to} 10 g / m ² (solid content, hereinafter similarly described), and preferably 3 to 7 g / m ² . 2g /
m The ² below, can not be a bond strength evenly, also, 10 g
/ M ² or more adhesive layer is disadvantageous not only in terms of cost, but also has high rigidity, cracks in the cover tape and thickening of the adhesive layer. This is not preferable except when special rigidity is required.

The thermoplastic resin used for the adhesive resin layer when forming the base material layer by sandwich lamination includes:
Low density polyethylene, ethylene / vinyl acetate copolymer,
From the ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, etc., the type of the stretched film serving as the base material layer and the primer layer can be selected and used. The thickness of the adhesive resin layer is determined according to the intended use at a minimum thickness in a range where film formation and adhesion are stable, for example, 10 to 30 μm. For the purpose of firmly and stably bonding the adhesive resin layer with the stretched film, a method such as applying a corona discharge treatment to the film, providing a primer layer, or performing ozone treatment on the hot-melted adhesive resin resin. It is preferable to use one kind or a combination of these.

The thickness of the base material layer is preferably 3 to 38 μm regardless of the single layer or two layers (or two or more layers), although it depends on the width of the carrier tape. If the base material layer is less than 3 μm, the strength and thermal stability of the cover tape are poor, and if it exceeds 38 μm, the heat transfer to the heat sealant layer is reduced. When the heat transfer speed is reduced, it is necessary to reduce the filling speed by increasing the heat sealing time in order to steadily fill the electronic components, which adversely affects productivity. In order to keep the filling rate from decreasing, it is necessary to increase the set temperature of the heat seal bar, and the temperature difference between the surface of the cover tape or carrier tape and the surface of the heat sealant layer increases. Therefore, the cover tape or the base material layer is thermally deformed or thermally decomposed, and foreign matter adheres to the heat seal bar to lower the thermal efficiency, thereby causing a reduction in the filling speed or a heat seal failure.

On the surface opposite to the heat sealant layer of the cover tape, that is, on the outermost surface, if necessary, conductive fine particles such as a surfactant, an organosilicon compound, conductive carbon black, metal vapor deposition, and metal oxide may be used. For example, it is desirable to perform an antistatic treatment using a method such as a method to prevent adhesion of dust and dust on the surface of the base sheet or to prevent generation of static electricity due to contact with another surface.

The intermediate layer acts as a cushion to uniformly adhere both sheets when the cover tape is heat-sealed with the carrier tape, or when the heat-sealed cover tape is peeled off from the carrier tape.
The adhesive strength between the intermediate layer 5 and the heat sealant layer 4 can be adjusted so that delamination occurs between the heat sealant layer 4 and the heat sealant layer 4. The intermediate layer 5 may have either a single-layer structure or a multilayer structure, and can be formed by combining two or more thermoplastic resins. Then, it can be formed in a single layer or a multilayer by a normal film forming method by an inflation method using a circular die or a casting method using a T die.

As the resin used for the intermediate layer, any of a homopolymer, a copolymer, and a polymer alloy can be used. However, while controlling the adhesive strength (peeling strength) with the heat sealant layer, the carrier tape and the cover tape can be used. Can be selected from those having a cushioning effect when heat sealing. For example, besides polyester, polyethylene, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer, ionomer, ethylene / propylene rubber, polypropylene, polyethylene, styrene / butadiene copolymer ,
It can be formed of a polymer alloy composed of two or more resins including a hydrogenated styrene / butadiene copolymer.

The intermediate layer has a glass transition temperature of 4 in addition to the above.
It can also be formed from a linear saturated polyester at 0 ° C. or higher. Examples of the linear saturated polyester having a glass transition temperature of 40 ° C. or more include alcohol components such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, and aliphatic dicarboxylic acids such as adipic acid and sebacic acid. Polyesters with dicarboxylic acids such as acids and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and diphenylcarboxylic acid. Specifically, ethylene glycol and terephthalic acid,
Ethylene glycol and isophthalic acid and terephthalic acid,
A cocondensation polymer of 1,4 cyclohexanedimethanol and ethylene glycol with terephthalic acid, or propylene glycol with terephthalic acid or isophthalic acid is used.
The reason why the glass transition temperature was set to 40 ° C. or higher was that the environmental conditions for using the cover tape did not reach 40 ° C. or higher.

The intermediate layer having the single-layer structure has a thickness of 10 to 100 μm.
m is preferred. If the thickness is less than 10 μm, the film-forming property is poor, and if it exceeds 100 μm, the heat sealing property with the cover tape is reduced.

The heat sealant layer of the cover tape of the present invention is formed of a thermoplastic resin comprising at least one of polyester, polyurethane, vinyl chloride / vinyl acetate copolymer, acrylic resin, and conductive fine particles described later. I have. Examples of combinations of two or more thermoplastic resins include a mixed varnish of polyurethane and a vinyl chloride / vinyl acetate copolymer (mixing ratio: 9: 1 to 4: 6), a polyester and a vinyl chloride / vinyl acetate copolymer. Mixed varnish with polymer (mixing ratio is 5: 5 to 9.5: 0.5), mixed varnish of acrylic resin and vinyl chloride / vinyl acetate copolymer (mixing ratio is 5: 5 to 9.5) : 0.5). When the intermediate layer is formed of a linear saturated polyester at 40 ° C., it is preferable to use a mixed varnish of polyurethane and a vinyl chloride / vinyl acetate copolymer.

The heat sealant layer of the cover tape of the present invention is mainly composed of one selected from carbon black, tin oxide fine particles, bisammonium organic sulfur semiconductor, and various surfactants. Then, it can be kneaded with a varnish made of a thermoplastic resin or a thermoplastic elastomer, or provided with a solution dispersed in a water / isopropyl alcohol-based solvent by roll coating or gravure coating. The coating amount of the electrostatic diffusion layer in the present invention is 0.01 to 30 g / m ² , preferably 0.05 to ² g / m ² .
m ² .

The material of the carrier tape to be used for the cover tape of the present invention is polyvinyl chloride, polystyrene, polyester (A-PET, PEN, PET-G,
PCTA), polypropylene, polycarbonate, polyacrylonitrile, ABS and the like. Then, as an antistatic measure, conductive carbon black fine particles, metal fine particles, conductive fine particles obtained by imparting conductivity to a metal oxide, an organosilicon compound or a surfactant are kneaded or coated with these. There is something to do. In addition, a polystyrene or ABS resin sheet is laminated on one or both sides of a polystyrene or ABS resin containing carbon black on one or both sides by co-extrusion. No. Alternatively, as the conductive treatment, a treatment in which a conductive polymer is formed on the surface of a plastic sheet can also be mentioned.

Hereinafter, the embodiment will be described in more detail. (Example 1) On one surface of a commercially available longitudinally uniaxially stretched polypropylene film having a draw ratio of 3.5 (base layer 1), 40% by weight of an ethylene / α-olefin copolymer and styrene.
Blend with 60% by weight of a butadiene block copolymer and dry lamination with a 30 μm-thick intermediate layer 5 made of a saacular die through a polyether / urethane-based adhesive layer 2. Further, a heat sealant layer 4 composed of 20% by weight of polyurethane, 4% by weight of a vinyl chloride / vinyl acetate copolymer and 36% by weight of tin oxide fine particles is coated on the intermediate layer 5 by gravure reverse so that the coating amount is 3 g / m ^2. The cover tape of Example 1 shown in FIG.

Example 2 A polyethylene terephthalate was melt-extruded with a T-die at 280 ° C. to form an unstretched film, and then stretched at 100 ° C. in a longitudinal direction at 3.5.
After stretching twice, it was heat-set at 210 ° C. to prepare a 6 μm-thick longitudinally uniaxially stretched film 1A. The unstretched film formed by the melt extrusion was stretched 3.5 times in the transverse direction at a stretching temperature of 120 ° C., and then heat-fixed at 210 ° C. to prepare a 6 μm-thick uniaxially stretched film 1B. And
The above-mentioned vertically uniaxially stretched film 1A and horizontal uniaxially stretched film 1
B was dry-laminated via a polyether / urethane-based adhesive layer 2 to form a base layer 1 having a thickness of 16 μm as shown in FIG. Then, in the same manner as in Example 1, the intermediate layer 5 is laminated via the adhesive layer 2 and then the heat sealant layer 4 is provided, and the cover tape 1 of Example 2 shown in FIG.
0 was configured.

Example 3 A commercially available product having a thickness of 10 μm
And a uniaxially stretched polypropylene film 1B having a draw ratio of 2 times and a uniaxially stretched polyester film 1 having a thickness of 6 μm and a draw ratio of 3.5 times prepared in Example 2.
A was dry-laminated via the adhesive layer 2 in the same manner as in Example 2 to form a base material layer 1 having a thickness of 16 μm shown in FIG. Then, a primer layer 2A is provided on the polyether / isocyanate-based surface of the longitudinally uniaxially stretched polyester film 1A, and a modified ethylene / vinyl acetate film (heat sealant layer 4A) having a thickness of 30 μm is combined with low density polyethylene (adhesive resin layer 3). 3) to form a cover tape 10 of Example 3 shown in FIG. 3 by sandwich lamination.

Each sample of the example was slit to a width of 5.5 mm, and a carrier tape 270 made of 3M polycarbonate was used.
Using five types, a heat seal temperature of 170 ° C., a heat seal time of 0.5 seconds, and a heat seal pressure of 3 kg / cm ²
The electronic component was filled under the conditions described above, but no deterioration of the base material layer was recognized by heat or pressure at that time. In addition, as a result of a high-speed mounting test, the cover tape was loaded without any breakage and with stable work.

[0028]

As described in detail above, the cover tape of the present invention is strongly stretched in the longitudinal direction and has a stretch ratio in the longitudinal direction of 2 times or more in the transverse direction, thereby reducing the size of the electronic component. A cover tape that can be sealed with a narrow carrier tape used for parts can be configured. Then, in the high-speed mounting process of the miniaturized electronic component, even if the cover tape is peeled off at a high speed, the cover tape can be used without being broken.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a cross section of a cover tape of the present invention.

FIG. 2 is a conceptual diagram showing a cross section of a cover tape on which a base material layer of the present invention is laminated.

FIG. 3 is a conceptual diagram showing a cross section of a cover tape showing another configuration of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base material layer 1A longitudinally stretched film 1B laterally stretched film 2 adhesive layer 2A primer layer 3 adhesive resin layer 4, 4A heat sealant layer 5 intermediate layer 10 cover tape

Claims (2)

[Claims] 1. A cover tape comprising at least a base material layer and a heat sealant layer and capable of being heat-sealed to a carrier tape having electronic components housed in recesses, wherein the stretch ratio of the base material layer of the cover tape in the longitudinal direction is 2 to 2. 8 times,
In addition, the stretch ratio in the transverse direction is 1 to 3 times, and the stretch ratio in the longitudinal direction is twice or more the stretch ratio in the transverse direction. Cover tape for packaging electronic components. 2. The cover tape, wherein a stretch ratio in the longitudinal direction of the base material layer is 2 to 8 times, a stretch ratio in the transverse direction is 1 to 3 times, and a stretch ratio in the longitudinal direction is horizontal. A plastic film strongly stretched uniaxially at least twice the stretching ratio in the direction, and the stretching ratio in the longitudinal direction is 1 to 3 times,
The stretch ratio in the transverse direction is 2 to 8 times, and the stretch ratio in the longitudinal direction is not more than の of the stretch ratio in the transverse direction. A cover tape for packaging electronic components.