JP2002154573A - Cover tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover tape with low dependence on a heat-sealing temperature and whose peeling strength can be easily adjusted, and to provide a carrier tape body comprising the cover tape. SOLUTION: The cover tape includes a biaxially oriented film layer, an intermediate layer of a polyolefin based resin and a heat seal layer of an ethylene-vinyl acetate based copolymer wherein a thickness of the heat seal layer is 2 μm or more, and the cover tape has a modulus in tension of 1,100 to 1,900 Mpa and a thickness of 70 μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover tape and a carrier tape body using the same, all of which are suitably used for packaging electronic parts.

[0002]

2. Description of the Related Art A cover tape is a bottom tape (also called a carrier tape or an embossed carrier tape).
It is mainly used for packaging electronic components as a lid material. The cover tape is required to have a heat seal property for easily obtaining a practical peel strength, and an easy-open property in which contents are not scattered at the time of opening and can be easily taken out.

[0003]

However, in the conventional cover tape, the peel strength changes greatly when the heat sealing temperature changes, and a stable peel strength can be obtained only in a specific heat sealing temperature range. In the case where the peel strength is less dependent on the sealing temperature, there is a problem that the heat sealing temperature is not sufficiently increased even if the heat sealing temperature is increased in order to further increase the peel strength. SUMMARY OF THE INVENTION The present invention provides a cover tape having a low dependence on the heat sealing temperature and capable of easily adjusting the peel strength, and a carrier tape body using the same.

[0004]

That is, the present invention comprises a biaxially stretched film layer, an intermediate layer of a polyolefin resin, and a heat seal layer of an ethylene vinyl acetate copolymer.
The thickness of the heat seal layer is 2 μm or more and the tensile modulus is 11
It is a cover tape having a thickness of 70 to 1900 MPa and a thickness of 70 μm or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The biaxially stretched film layer is composed of a biaxially stretched film of a thermoplastic resin. For example, a biaxially oriented polyethylene terephthalate film, a biaxially oriented polypropylene film, a biaxially oriented polystyrene, a biaxially oriented polyamide film, or the like can be used. In particular, it is preferable to use a biaxially stretched polyethylene terephthalate film. An antistatic agent coated or kneaded and subjected to antistatic treatment, corona treatment, or the like can also be used.

[0006] The intermediate layer is made of a polyolefin resin,
Here, the polyolefin-based resin is obtained by polymerizing an olefin as a main component, for example, low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, ethylene-1-butene copolymer, ethylene vinyl acetate-based resin. Copolymer, ethylene-acrylate copolymer,
There are ethylene-maleic acid copolymer, styrene-ethylene graft copolymer, styrene-propylene graft copolymer, styrene-ethylene-butadiene block copolymer, propylene polymer, ethylene polymer and the like and blends thereof. These can be used alone or in combination of two or more. Ethylene-1
-Blend or copolymerized with butene or a copolymer of ethylene and a vinyl group having a carboxylic acid group, for example, an ethylene-acrylate ester, an ethylene-vinyl acetate copolymer, or a terpolymer with an acid anhydride. Can also. Further, thermoreversible cross-linking resins described in JP-A-6-57062, JP-A-7-94029 and JP-A-11-106578 can also be used.

If a biaxially stretched film layer, an intermediate layer of a polyolefin resin and a heat seal layer of an ethylene vinyl acetate copolymer are provided, the adhesive strength between the biaxially stretched film layer and the intermediate layer will be more sufficient. For this purpose, use of an anchor coating agent or surface treatment is one of the preferable constitutions in the present invention. As the anchor coating agent, a two-component curable isocyanate-based anchor coating agent can be used to strengthen the adhesion between the biaxially oriented polyethylene terephthalate of the biaxially oriented film layer and the polyolefin resin of the intermediate layer. In order to further strengthen the adhesion between the anchor coating agent and the biaxially oriented polyethylene terephthalate film, a corona treatment can be applied to the biaxially oriented polyethylene terephthalate film and an ozone treatment can be applied to the polyolefin resin.

The thickness of the heat seal layer is preferably 2 μm or more. The thinner the heat seal layer, the better the transparency of the cover tape, but if it is less than 2 μm, it is difficult to obtain a stable peel strength. An increase in the thickness of the heat seal layer does not significantly affect the peel strength, but is preferably within 10 μm to improve transparency.

The ethylene-vinyl acetate copolymer of the heat seal layer is a copolymer obtained by copolymerizing ethylene and vinyl acetate as essential components, and a copolymer obtained by copolymerizing other components within a range not to impair the object of the present invention. Can also be used. (A) 0 to 30% by weight having a glass transition temperature of 40 ° C. or more and less than 65 ° C., (B) 65 ° C. or more and 85 ° C.
Less than 0 to 100% by weight, (C) 85 ° C or more and 1
Those having a temperature of less than 05 ° C and containing 0 to 75% by weight can be suitably used. Here, if (A) is more than 30% by weight, the low-temperature sealing property will be good, but blocking will easily occur, and if (C) exceeds 75% by weight, it will be difficult to obtain low-temperature sealing property. An organic or inorganic filler or a fatty acid amide can be used together as a blocking inhibitor in the heat seal layer. The fatty acid amide preferably has a melting point of 70 ° C. to 120 ° C. For example, olefin acid amide, erucic acid amide, stearic acid amide and the like can be used. As the filler, inorganic particles such as silicon nitride and aluminum oxide, and plastic particles such as polystyrene particles and polyethylene resin can be used. The heat seal layer can be obtained by applying a water / various alcohol-ethylene-vinyl acetate copolymer emulsion, for example, water / isopropyl alcohol, to the film of the intermediate layer. As a coating method, any of known methods can be used. For example, there are an air knife method, a curtain coating method, a roller coating method, a gravure coating method, and a bar coating method.

The cover tape of the present invention has a tensile modulus of 11
00 to 1900 MPa, and the total thickness is within 70 μm. In such a configuration, good peel strength can be obtained. That is, when the peel strength changes for each material to be heat-sealed, by adjusting the film thickness without changing the sealant composition, it is possible to obtain a cover tape having stable strength in a wide temperature range. The peel strength can be adjusted by changing the thickness of the intermediate layer and the biaxially stretched film layer constituting the film. When the thickness of the intermediate layer is increased, the peel strength after heat sealing increases, and when it is reduced, the peel strength can be decreased. When the thickness of the biaxially stretched film is reduced, the peel strength after heat sealing increases, and when the thickness is increased, the peel strength can be reduced. By controlling the thickness of the intermediate layer and the biaxially stretched film layer, the peel strength can be controlled.

It is preferable that at least one surface of the cover tape is subjected to an antistatic treatment. As the antistatic agent, a surfactant type antistatic agent, a polymer type antistatic agent, a conductive agent and the like can be used. Although there is no particular limitation on the antistatic treatment method, for example, a method such as coating with a roll coater using a gravure roll or the like and kneading the adhesive layer can be used.

Commercially available products such as a biaxially stretched polyethylene terephthalate film, a polyolefin-based resin, and an ethylene-vinyl acetate-based copolymer can be used. Additives that do not impair the significance of the invention,
Fillers and other thermoplastic resins can be used in combination.

The cover tape is an IC together with the bottom tape.
And the like, and can be suitably used as a packaging body for electronic components and a carrier tape body. The type of the bottom tape is not particularly limited, and for example, a tape made of a styrene-based resin or a polycarbonate-based resin can be suitably used.

[0014]

Embodiments of the present invention will be described below. (Examples 1 to 14, Comparative Example 1) A biaxially stretched polyethylene terephthalate film (manufactured by Unitika) as a biaxially stretched film layer and a crosslinked polyethylene resin (trade name: Lexpearl: manufactured by Nippon Polyolefin Co., Ltd.) as a polyolefin resin for an intermediate layer ) To prepare a film in which the thicknesses of the biaxially stretched film layer and the intermediate layer were changed. An aqueous emulsion ethylene-vinyl acetate copolymer was used as the heat seal layer, and its glass transition temperature was (A) 40 ° C.
(A): (B): (C) 25:50: (B) 65 ° C or more and less than 85 ° C, (C) 85 ° C or more and less than 105 ° C. 25% by weight, as a blocking inhibitor, a mixture of 0.7% by weight of stearic acid amide (manufactured by Nippon Kasei Co., melting point: 102 ° C.) and 1% by weight of silica (manufactured by Nippon Silica) were coated and dried. Then, a cover tape was obtained. (Comparative Example 2) Thermofilm ALS which is a commercially available cover tape
(Manufactured by Denki Kagaku Kogyo KK) was used. For these, the heat sealability shown below was evaluated. Seal head width 32
A heat seal film was applied to a polystyrene carrier tape for electronic packaging at 140 ° C. under the conditions of mm × 0.5 mm, a seal pressure of 0.4 MPa, and a seal speed of 2 times / second.
Sealing was performed at 50 ° C and 170 ° C on a polycarbonate carrier tape, and the average peel strength was measured. This is shown in Table 1,
It is shown in FIG.

[0015]

[Table 1]

[0016]

[Table 2]

In the examples, all the heat seal layers were cohesively broken.

According to the present invention, there is provided a cover tape excellent in easy-opening property which has a small seal temperature dependency and can be adjusted so that the practical peel strength becomes almost constant in a wide temperature range. can do.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 7/00 CFD C08L 23/08 4J002 C08L 23/08 31/04 S 31/04 B65D 85/38 SF Terms (reference) 3E067 AA11 AB41 AC04 BA02A BB14A BB15A BB25A CA21 CA24 EA09 EA13 EB27 EC07 FA01 FB08 FC01 3E086 AB02 AD30 BA04 BA15 BB51 CA31 3E096 AA06 BA08 CA14 CC01 DA17 DC03 EA02 BA03 GA03 FA01 BA03 FA03 4F100 AA20 AH03 AK03B AK04 AK42 AK68C AT00A BA03 BA07 BA10A BA10C CA17 CA22C EH46 EJ38A GB41 JA05C JG03C JK01C JK06 JL12C JL14 YY00C 4J002 BB06W BB06X BB06Y BE03Y BE03X BE03Y BE03X

Claims (5)

[Claims] 1. A biaxially stretched film layer, an intermediate layer of a polyolefin resin and a heat seal layer of an ethylene vinyl acetate copolymer, wherein the heat seal layer has a thickness of 2 μm or more, a tensile modulus of 1100 to 1900 MPa, 7 thickness
A cover tape having a thickness of 0 μm or less. 2. An ethylene-vinyl acetate copolymer having a glass transition temperature of (A) 40 ° C. or higher and lower than 65 ° C.
% By weight, (B) from 65 ° C. to less than 85 ° C. 0 to 100
% By weight, and (C) 85 ° C. or higher and lower than 105 ° C. 0
Cover tape consisting of ~ 75% by weight. 3. The cover tape according to claim 1, wherein at least one surface is subjected to an antistatic treatment. 4. A carrier tape body comprising the cover tape and the bottom tape according to claim 1, wherein the carrier tape houses electronic components. 5. The carrier tape according to claim 4, wherein the bottom tape is made of a styrene resin or a polycarbonate resin.