JPH09175592A - Cover tape for packing electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a non-chargeable cover tape excellent in hermetic sealability and easy peelability and not fluffing pasteboard at a time of peeling by laminating a seal layer consisting of an ethylene polymer and a non-chargeable potassium ionomer in a specific ratio to apply activation treatment thereto. SOLUTION: A seal layer consisting of 70-90 pts.wt. of an ethylene polymer selected from low density polyethylene and an ethylene/unsaturated ester copolymer and 30-100 pts.wt. of a non-chargeable potassium ionomer is laminated on a base material layer, if necessary, through an intermediate layer and subjected to activation treatment by corona treatment. The non-chargeable potassium ionomer used in the seal layer contains 10-30wt.% of unsaturated carboxylic acid and consists of two or more kinds of ethylene/unsaturated carboxylic copolymers different in the content of unsaturated carboxylic acid and 0.1-5wt.% of polyhydric alcohol can be compounded with the seal layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover tape for a carrier tape made of paper in which storage cavities for storing chip-type electronic components are continuously scattered. More specifically, the present invention relates to a non-chargeable cover tape which is excellent in hermeticity and easy peeling property when heat-sealed to the carrier tape mount, and the mount does not fluff when peeled off.

[0002]

2. Description of the Related Art Chip type electronic components such as transistors, diodes and ICs are provided with storage cavities so that they can be easily attached to electronic circuit boards after their manufacture to prevent contamination during storage and transportation. It is stored in the carrier tape that it has.
As one of the structures of such a carrier tape, a mount portion is provided with continuous cutouts, and a back tape is adhered to one of the mounts to form the cutout portion as a storage space. It is known that a cover tape is adhered and sealed after being stored.

As such a cover tape, firstly,
In order to prevent damage to electronic parts due to static electricity generated during transportation or peeling of a cover tape, a material having excellent antistatic property is required. Further, the cover tape is required to be easily peeled off while having excellent sealability with the mount. When the cover tape is peeled off, it is also required that the backing paper does not fluff so that dust does not adhere to the electronic components.

A low density polyethylene or an ethylene / unsaturated ester copolymer blended with a tackifier and a low molecular weight organic antistatic agent has a suitable adhesive force and antistatic property, and is a cover tape. It can be said that the material is considerably excellent, but there is concern that the adhesive force to the mount and the antistatic performance change over time due to the bleed-out of the antistatic agent.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present inventors
We investigated cover tape materials that have long-lasting antistatic performance, excellent sealability to a backing paper, and easy peeling properties, and that the backing paper does not fluff when peeled from the backing paper.
As a result, they have found that the cover material having the following laminated structure has the above-mentioned properties, and have reached the present invention.

[0006]

According to the present invention, an ethylene polymer (A) 70 to 90 selected from low density polyethylene and an ethylene / unsaturated ester copolymer is provided in a base material layer, if necessary with an intermediate layer interposed therebetween. The present invention relates to a cover tape for packaging electronic parts, characterized in that a seal layer comprising 30 parts by weight of a non-charged potassium ionomer (B) and 30 parts by weight of the non-charged potassium ionomer is laminated, and the sealing layer is activated.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an ethylene polymer (A) selected from low-density polyethylene and an ethylene / unsaturated ester copolymer is used for a seal layer of a cover tape.
A composition of 70 to 90 parts by weight, preferably 75 to 85 parts by weight and 30 to 10 parts by weight, preferably 25 to 15 parts by weight of a non-charged potassium ionomer (B) is used.

As the ethylene polymer (A), low density polyethylene or ethylene / unsaturated ester copolymer can be used. The low density polyethylene has a density of 0.900 to 0.935 g / cm ³ , and preferably a density of 0.9.
It may be 905 to 0.930 g / cm ³ and may be obtained by a high pressure method, or may be obtained by copolymerizing ethylene and an α-olefin having 4 or more carbon atoms by a medium or low pressure method. A typical example of the latter method is a method in which a highly active titanium catalyst or a metallocene catalyst is used for copolymerization in a liquid phase or a gas phase, and such a method is already well known.

The ethylene / unsaturated ester copolymer has an unsaturated ester content of 1 to 30% by weight, preferably 5 to 20% by weight. Examples of the unsaturated ester include vinyl esters such as vinyl acetate, unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate and isobutyl methacrylate. be able to.

As the ethylene polymer (A), 19
The melt flow rate at 0 ° C. and 2160 g load is
0.1 to 200 g / 10 minutes, particularly 1 to 50 g / 10 minutes are preferable.

The uncharged potassium ionomer (B) used in the seal layer is a part or all of the ethylene copolymer consisting of ethylene and an unsaturated carboxylic acid or, as an optional component, another monomer, which is potassium. Neutralized potassium ionomer which imparts sufficient antistatic property to the sealing layer, for example, a surface resistivity at 23 ° C. and 30% RH of 10 ¹³ Ω or less, preferably 10 ¹² Ω or less. It is a thing. Such a non-chargeable potassium ionomer varies depending on whether or not an additive effective for improving the non-charge property is blended in the seal layer, but the unsaturated carboxylic acid content and the degree of neutralization should be adjusted to an appropriate range. Can be obtained by Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic anhydride, monoethyl maleate and the like, but acrylic acid or methacrylic acid is particularly preferable. Examples of the other monomer which can be a copolymer component include the above-mentioned vinyl ester and unsaturated carboxylic acid ester as representative examples. Such another monomer can be contained in the copolymer at a ratio of, for example, 0 to 30% by weight.

As the non-charged potassium ionomer,
It is preferable to use an ionomer obtained by neutralizing two or more kinds of ethylene / unsaturated carboxylic acid copolymers having different average acid contents with potassium ions. One example of such an ionomer is, for example, two or more kinds of copolymers having different acid contents having an average acid content of 10 to 30% by weight, preferably 11 to 20% by weight, for example, the highest acid content and the lowest acid content. Of two or more kinds of ethylene / unsaturated carboxylic acid copolymers having a difference in acid content of 1 wt% or more, preferably 2 to 20 wt%, the average degree of neutralization with potassium ions is 60% or more, preferably It is a mixed ionomer of 70% or more. In this case, when using one having a low average acid content, it is desirable to use an antistatic agent such as a polyhydric alcohol together. As another example, an acid content of 13-
30% by weight, preferably 15-25% by weight of ethylene
The unsaturated carboxylic acid copolymer has a degree of neutralization with potassium ions of 60% or more, preferably 70% or more.
Also in this case, it is preferable to use a non-static property improver when using a compound having a low acid content.

The seal layer may contain various additives in addition to the ethylene polymer (A) and the non-charged potassium ionomer (B). As such an additive,
Examples thereof include antistatic agents such as glycerin, trimethylolpropane, pentaerythritol and polyethylene glycol, antioxidants, various stabilizers, slip agents and colorants. The antistatic property improver is effectively added, for example, in a proportion of 0.1 to 5% by weight, particularly 0.2 to 3% by weight.

The cover tape of the present invention is one in which a seal layer made of the above composition is formed on a base material with or without an intermediate layer, and the seal layer is activated. The base material is preferably a thermoplastic resin having excellent mechanical strength,
For example, polypropylene, polyethylene terephthalate,
Biaxially oriented films such as nylon 6 and nylon 66 are suitable materials. Examples of the optionally used intermediate layer include those that improve the adhesiveness between the base material and the seal layer, such as those exemplified above as the ethylene polymer which is one component of the seal layer.

Although the thickness of each layer in the cover tape is arbitrary, for example, the base material has a thickness of 1 to 200 μm, particularly 10 to 5
0 μm, intermediate layer 0 to 50 μm, especially 10 to 30 μm
m, the sealing layer is 5 to 100 μm, especially 10 to 50 μm
It is preferable to set it in the range. Such a cover tape can be obtained by a known laminating method. For example, a method of extrusion laminating a seal layer on a substrate, a method of co-extrusion laminating an intermediate layer and a seal layer on a substrate, and the like can be mentioned.

If the laminate obtained as described above is used as it is as a cover tape, the adhesive strength to the mount is too small and the sealing property is poor. By activating the seal layer, it is possible to impart an appropriate adhesive force to the mount and prevent fuzz of the mount when peeled from the mount. Examples of the activation treatment include corona treatment and ozone treatment, but corona treatment is the most simple and preferable. The corona treatment condition is, for example, 5 watt / m ² /
It is preferable that the discharge amount is not less than min, preferably 10 to 200 watt / m ² / min.

[0017]

The cover tape of the present invention has excellent properties as a carrier tape for packaging electronic parts. That is, after storing electronic components in a carrier tape in which electronic component storage cavities are continuously provided, which is obtained by adhering a back tape to a mount provided with cutout portions that are continuously scattered, this is sealed. When used as a cover tape for, since the cover tape of the present invention is excellent in antistatic property,
It is possible to prevent damage to electronic components due to electrostatic damage. The mount is resin-coated, and when the cover tape of the present invention is heat-sealed to such a mount, it can be sealed in a wide temperature range and with an appropriate seal strength, and the seal strength does not deteriorate with time. It has excellent sealing properties and can be easily peeled off. In addition, the cover tape peels off neatly during peeling, and the fuzz of the mount does not occur.

[0018]

EXAMPLES The types of materials used for the layers of the laminates used in the examples, the laminating conditions, the corona treatment conditions, the heat seal strength measuring method for the laminates, etc. are as follows.

1. Laminated Material (1) Base Material Layer: Biaxially Stretched Polypropylene Film (TOPU Cell Corporation, OPU-1, Thickness 20 μm)

(2) Intermediate layer: low-density polyethylene (Mitsui Petrochemical Industry Co., Ltd., Mirason 16, MFR = 4 g /
10 minutes)

(3) Seal layer resin Composition comprising the following (a) (b) (c) (a) Ethylene / vinyl acetate copolymer (vinyl acetate content 1
0% by weight, MFR 9g / 10 minutes) ... 8
0% by weight (b) Non-charged potassium ionomer Two types of ethylene / methacrylic acid copolymers below: Methacrylic acid content 15% by weight, MFR 60 g / 10
Min Methacrylic acid content 10% by weight, MFR 40g / 10
A composition consisting of an ionomer obtained by neutralizing 83% by mole of a 1/1 mixture of potassium ion with 19% by weight and (c) glycerin with 1% by weight (MFR = 8 g / 10 min).

2. Laminating conditions Equipment Modern Machinery Extruder 65mmφ L / D = 28 Screw Three Stage Type CR = 4.78 Die Inner Deckel Type Die Aperture 0.8 × 500mm Air Gap 120mm Die Setting Temperature 230 ℃ Line Speed 80m / min

3. Corona treatment condition device Corona surface treatment machine manufactured by Kasuga Electric Co., Ltd. Corona voltage 160V Current 10A Line speed 40m / min Corona treatment density 60W ・ min / m ²

[0024] 4. Heat seal strength measurement method Substrate to be sealed Carrier tape paper (Honshu Paper Co., Ltd., HJ carrier tape paper, 580 g / m ² ) Sealing conditions Seal pressure 0.2 MPa Sealing time 0.5 seconds Seal bar 10 × 300 mm Tensile Test Tensile speed 300 mm / min Peeling angle 180 degrees Specimen width 5 mm

[0025]

EXAMPLE A PP biaxially stretched film of (1) having a thickness of 20 μm as a substrate, a low-density polyethylene of (2) extruded and laminated to have a thickness of 20 μm as an intermediate layer, and a extrusion layer having a thickness of 30 μm as a sealing layer ( Using the ethylene copolymer / potassium ionomer composition of 3), a three-layer constitution film was prepared under the above-mentioned laminating conditions.

This three-layered film and its seal layer, which had been subjected to corona treatment under the above conditions, were heat-sealed with a carrier tape paper (manufactured by Honshu Paper Co., Ltd.) and the heat-sealing strength was measured. The results are shown in Table 1.
As a result, the heat-sealing strength of the corona-treated three-layered film of the present invention against carrier tape paper was improved to about twice as much as that without corona treatment, and the strength did not decrease with time. was gotten. Moreover, the cover tape was peeled off neatly at the time of peeling, and no fuzz of the mount was caused.

[0027]

[Table 1]

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B65D 73/02 B65D 73/02 B

Claims (5)

[Claims] 1. An uncharged potassium ionomer containing 70 to 90 parts by weight of an ethylene polymer (A) selected from low-density polyethylene and an ethylene / unsaturated ester copolymer in a base material layer, if necessary with an intermediate layer interposed therebetween. (B) A cover tape for packaging electronic parts, comprising a sealing layer comprising 30 to 10 parts by weight, the sealing layer being activated. 2. An uncharged potassium ionomer (B)
Is an ionomer of two or more kinds of ethylene / unsaturated carboxylic acid copolymers having an average unsaturated carboxylic acid content of 10 to 30% by weight and different in unsaturated carboxylic acid content. tape. 3. The non-chargeable potassium ionomer is an ionomer of an ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 13 to 30% by weight.
Or the cover tape according to 2. 4. The sealing layer contains polyhydric alcohol in an amount of 0.1 to 10.
The cover tape according to any one of claims 1 to 3, wherein the cover tape is blended at a ratio of 5% by weight. 5. The activation treatment is a corona treatment.
The listed cover tape.