JP2003175968A - Cover tape and carrier tape body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cover tape that has less change in joining strength in a high temperature/high humidity environment and has satisfactory transparency. <P>SOLUTION: The cover tape has a joining layer comprising an ethylene vinyl acetate copolymer resin and bridged acrylic particles, the ratio of bridged acrylic particles to ethylene vinyl acetate copolymer resin being 0.04 or greater. The cover tape can be formed from at least biaxially oriented film outermost layer, an intermediate layer, and the joining layer. The joining layer may comprise a surface-active agent and a conductive metal oxide filler. As the intermediate layer, a polyolefin resin can be used. <P>COPYRIGHT: (C)2003,JPO

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 packaging electronic parts and a carrier tape body using the cover tape.

[0002]

2. Description of the Related Art Contents such as electronic parts are stored and transported in a plastic carrier tape (also called a bottom tape or an embossed carrier tape) in which pockets are continuously embossed. The cover tape is used as a cover agent that prevents the contents from falling off. A cover tape in which a hot melt adhesive layer is laminated on a PET film as a base material is often used. For the bottom tape, a styrene-based resin or a polycarbonate-based resin that is easily embossed is often used. As examples of these, JP 2001-59077 A and 2001
-30430, JP-A-2000-16486, JP-A-2
000-7021, JP-A-11-301775 and the like.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a cover tape having good transparency and little fluctuation in adhesive strength in a high temperature and high humidity storage environment.

[0004]

The present invention provides an adhesive layer containing an ethylene vinyl acetate copolymer resin and crosslinked acrylic particles in a crosslinked acrylic particle / ethylene vinyl acetate copolymer resin ratio of 0.04 or more. A cover tape having the carrier tape body using the cover tape.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The adhesive layer can be obtained by coating a base film with an ethylene vinyl acetate copolymer resin emulsion and crosslinked acrylic particles and drying. Examples of the coating method include an air knife method, a curtain coating method, a roller coating method, a gravure coating method, and a bar coating method. The ethylene-vinyl acetate copolymer is a copolymer of ethylene and vinyl acetate, and it is also possible to use a copolymer obtained by copolymerizing a small amount of other components with a content of about 10% or less. It is also possible to use two or more materials having different compositions. Minimum film forming temperature Temperature is (A) 40 ° C to 65
0 to 30% by weight of ethylene vinyl acetate copolymer resin emulsion of less than ℃, calculated as solid content, (B) 65 to 85 ℃
Less than 0 to 100% by weight, (C) 85 ° C to 105 ° C
Blends consisting of less than 0 to less than 75% can be suitably used.

[0006] Crosslinked acrylic particles are particles of acrylic resin that are crosslinked. It may be a homopolymer or copolymer of an acrylic monomer, or a copolymer of an acrylic monomer and another monomer. It is a crosslinked polymer. The glass transition temperature of the polymer is preferably 25 ° C. or higher. It is also possible to use a particle having a functional group introduced on its surface, or a particle having at least a part thereof bound to a metal. The method for producing the crosslinked acrylic particles is not particularly limited. Emulsion polymerization and soap-free emulsion polymerization can be used. Cross-linked particles of polymethyl acrylate, polyethyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, etc. can be used. It is preferable that a substantial part of the particles are distributed in a particle size range of 1 to 90 μm. If the particle size is large, the blocking prevention effect is easily obtained. An average particle size of 0.1 to 50 μm can be used, preferably 7 μm or more and 15 μm.
The following is desirable from the viewpoint of transparency because the effect is easily obtained without adding a small amount.

The crosslinked acrylic particle / ethylene vinyl acetate copolymer resin ratio is 0.04 or more. If it is less than that, the anti-blocking effect and the peel strength stability over time deteriorate.
The crosslinked acrylic particle / ethylene vinyl acetate copolymer resin ratio is preferably 0.2 or less, more preferably 0.1 or less.

A surfactant and a conductive metal oxide can be added to the adhesive layer as an antistatic treatment. Organic or inorganic fillers and fatty acid amides can be added as antiblocking agents. As the fatty acid amide, one having a melting point of 70 ° C. to 120 ° C. is preferable, and for example, olefin acid amide, erucic acid amide, stearic acid amide, etc. can be used, and inorganic particles of silicon nitride, aluminum oxide, titanium oxide, etc. as the filler. It is also possible to use plastic particles such as polystyrene particles and polyethylene resin. When these organic and inorganic fillers modified with a conductive metal are used, it is possible to have both blocking properties and antistatic properties. When a polymer type surfactant is used, troubles such as adhesive strength due to bleed-out phenomenon hardly occur.
In order to obtain transparency, it is desirable to obtain the antistatic effect by using a surfactant. In order to obtain an antistatic effect, for example, stannic oxide sol, zinc antimonate sol, antimony-doped tin oxide or the like can be added as a conductive metal oxide. In order to improve the transparency, it is preferable to use a needle-shaped conductive filler having a small particle size and to reduce the addition amount.

In the cover tape comprising a base film / adhesive layer, the base film preferably has an outermost layer / intermediate layer structure composed of a biaxially stretched film. Outermost layer of biaxially stretched film
The structure is an intermediate layer / adhesive layer.

The outermost biaxially stretched film is, for example, a biaxially stretched polyethylene terephthalate film,
Polyester resin film such as polyethylene naphthalate, polyolefin resin film such as polypropylene,
Examples include polystyrene film and polyamide film.
A biaxially stretched polyester resin film can be preferably used. It is also possible to use an antistatic-treated or corona-treated biaxially stretched film coated or kneaded with an antistatic agent.

The intermediate layer enhances the adhesion between the adhesive layer and the carrier tape at the time of heat sealing, and plays a role of a cushion material at the time of heat sealing at the carrier tape. A polyolefin resin can be preferably used for the intermediate layer. As the polyolefin resin, low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene-1-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, ethylene-malein. Examples thereof include acid copolymers, styrene-ethylene graft copolymers, styrene-propylene graft copolymers, styrene-ethylene-butadiene block copolymers, propylene polymers, ethylene polymers and the like, and blends thereof. They can be used alone or in combination. Blended with ethylene-1-butene or a copolymer of ethylene and a vinyl group having a carboxylic acid group, for example, an ethylene-acrylic acid ester, an ethylene-vinyl acetate copolymer, or a ternary copolymer with an acid anhydride. The above can be preferably used. JP-A-6-57
062, JP-A-7-94029, and JP-A-11-10.
The thermoreversible cross-linking resin described in 6578 can also be used. An anchor coating agent may be used or a surface treatment may be applied to further increase the adhesive force between the biaxially stretched film and the polyolefin resin. As the anchor coating agent, in particular, in order to strengthen the adhesion between the biaxially stretched polyethylene terephthalate and the polyolefin resin, 2
A liquid-curable isocyanate-based anchor coating agent can be preferably used. In order to strengthen the adhesion between the anchor coating agent and the biaxially stretched polyethylene terephthalate film, the biaxially stretched polyethylene terephthalate film side may be subjected to corona treatment and the polyolefin resin side may be subjected to ozone treatment.

The surface resistivity of the adhesive layer of the cover tape is 10
It is preferably in the range of ⁶ to 10 ¹² Ω / □. If the surface resistivity is high, the antistatic effect is deteriorated, and it becomes difficult to protect electronic parts and the like that require protection from electrostatic damage. If it is low, the electronic components may be energized from the outside through the cover tape, increasing the risk of electrical damage to the electronic components.

The cover tape is preferably transparent and preferably has a haze value of 30% or less. The haze value is represented by the percentage of diffused light transmittance / total light transmittance, and the lower the value, the better the transparency.

The cover tape may be subjected to antistatic treatment. Antistatic treatment is performed on the outermost layer of the biaxially stretched film by using a surfactant-based antistatic agent as an antistatic agent, a polymer type antistatic agent or a conductive agent made of a metal oxide such as a conductive oxide sol. be able to.

The cover tape can be preferably used as a cover material for a carrier tape. An electronic component or the like can be stored in the embossed portion of the carrier tape, and the cover tape can be heat-sealed to the carrier tape to form a carrier tape body.

[0016]

EXAMPLES Examples and comparative examples of the present invention are shown below. Example 1 An antistatic treated biaxially stretched polyester film (16 μm thickness, manufactured by Toyobo Co., Ltd.) was used as an outermost layer, and a cross-linked polyethylene resin (Rex Pearl, manufactured by Nippon Polyolefin Co., Ltd.) was extrusion coated as an intermediate layer. A material film was produced. Cross-linked acrylic particles with an average particle size of 7 μm (M
R7G, manufactured by Soken Chemical Industry Co., Ltd.) was added to obtain an ethylene vinyl acetate copolymer emulsion (minimum film forming temperature 70 ° C., Et ratio 83 wt%) in which a crosslinked acrylic particle / ethylene vinyl acetate copolymer resin ratio was 0.04. After coating and drying, a film sample for cover tape was obtained.

Example 2 The same base film as in Example 1 was used. Bondip (made by Konishi) as an antistatic agent is a crosslinked acrylic particle (MR7G, manufactured by Soken Chemical Co., Ltd.) having an antistatic agent solid content / ethylene vinyl acetate copolymer resin ratio of 0.125 and an average particle size of 7 μm.
Ethylene vinyl acetate copolymer emulsion in which the ratio of crosslinked acrylic particles / ethylene vinyl acetate copolymer resin was 0.08 (minimum film forming temperature 70 ° C., Et ratio 83
wt%) was coated on a base film and dried to obtain a film sample for a cover tape.

Example 3 The same base film as in Example 1 was used. As an antistatic agent, conductive acicular antimony-doped tin oxide (FS-10P,
(Ishihara Techno Co., Ltd.) is a solid content of antistatic agent / ethylene vinyl acetate copolymer resin ratio 0.4, crosslinked acrylic particles (MR7G, Soken Chemical Co., Ltd.) having an average particle size of 7 μm are crosslinked acrylic particles / ethylene vinyl acetate copolymer weight. A base film was coated with an ethylene-vinyl acetate copolymer emulsion (AD-37P2795J, manufactured by Toyo Morton Co., Ltd.) added to give a combined resin ratio of 0.08 and dried to obtain a cover tape film sample.

Comparative Example 1 The same base film as in Example 1 was used. An ethylene-vinyl acetate copolymer emulsion (minimum film-forming temperature 70 ° C, Et ratio 83 wt%) to which Bondip (manufactured by Konishi) was added as an antistatic agent at an antistatic agent solid content / ethylene-vinyl acetate copolymer resin ratio of 0.125. ) Was coated and dried to obtain a film sample for a cover tape.

Comparative Example 2 The same base film as in Example 1 was used. Bondip (made by Konishi) as an antistatic agent is a crosslinked acrylic particle (MR7G, manufactured by Soken Chemical Co., Ltd.) having an antistatic agent solid content / ethylene vinyl acetate copolymer resin ratio of 0.125 and an average particle size of 7 μm.
Ethylene vinyl acetate copolymer emulsion in which a cross-linked acrylic particle / ethylene vinyl acetate copolymer resin ratio was 0.02 (minimum film forming temperature 70 ° C., Et ratio 83
wt%) was coated on a base film and dried to obtain a film sample for a cover tape.

Comparative Example 3 The same base film as in Example 1 was used. Bondip (manufactured by Konishi) as an antistatic agent is a crosslinked acrylic particle (MR2G, manufactured by Soken Chemical Co., Ltd.) having an antistatic agent solid content / ethylene vinyl acetate copolymer resin ratio of 0.125 and an average particle diameter of 2 μm.
Ethylene vinyl acetate copolymer emulsion in which a cross-linked acrylic particle / ethylene vinyl acetate copolymer resin ratio was 0.02 (minimum film forming temperature 70 ° C., Et ratio 83
wt%) was coated on a base film and dried to obtain a film sample for a cover tape.

Comparative Example 4 The same base film as in Example 1 was used. As an antistatic agent, conductive acicular antimony-doped tin oxide (FS-10P,
(Ishihara Techno Co., Ltd.) is an ethylene vinyl acetate copolymer dispersion liquid (V10) having an antistatic agent solid content / ethylene vinyl acetate copolymer resin ratio of 0.4 and an average particle diameter of 12 μm.
Ethylene vinyl acetate copolymer dispersion particles / ethylene vinyl acetate copolymer resin ratio of 0.24 (AD-37P2795J, Toyo Morton Co., Ltd.) Product) on the base film and dried,
A film sample for cover tape was obtained.

Comparative Example 5 The same base film as in Example 1 was used. As an antistatic agent, conductive acicular antimony-doped tin oxide (FS-10P,
Low molecular weight ethylene dispersion liquid (W400, manufactured by Mitsui Chemicals, Inc.) having an antistatic agent solid content / ethylene vinyl acetate copolymer resin ratio of 0.4 and an average particle size of 4 μm is used as a low molecular weight ethylene dispersion particle. / Ethylene vinyl acetate copolymer resin ratio 0.24 added ethylene vinyl acetate copolymer emulsion (AD-
37P2795J, manufactured by Toyo Morton Co., Ltd.) was coated on a substrate film and dried to obtain a film sample for a cover tape.

The obtained film sample for a cover tape was cut to obtain a cover tape as a cover material for a carrier tape. The following evaluations were performed for them. Heat sealability evaluation Seal head width 0.5mm × 2, Seal pressure 0.4MP
a, at 170 ° C. under the condition of a sealing rate of 2 times / sec, the cover tape was sealed on a transparent polystyrene sheet for electronic packaging material (Clearene sheet CST-2401, Denki Kagaku Kogyo), and the initial average The peel strength was determined. As an accelerated environmental test, in a hot and humid environment (52 ° C, 95% R
After the carrier tape body sealed in (H) was stored for 5 days, the peel strength was measured. Evaluation of surface resistance value using Hiresta UP manufactured by Mitsubishi Chemical Co., Ltd., measurement voltage of 500V based on JIS method, measurement time of 1 minute, measurement environment of 23 ° C. 5
The surface resistance value was determined at 0% RH. Transparency evaluation Haze (cloudiness value) was measured using an integrating sphere type measuring device according to measuring method A according to JIS-K7105 (1998). The unit is%.

[0025]

[Table 1]

At the initial stage of the peeling morphology, all were peeled off by cohesive failure. 52 ° C 95%
R. H. After storage for 5 days, the examples were peeled by cohesive failure, the comparative example 1 by interfacial peeling, and the comparative examples 2, 3 by interfacial breaking.

[0027]

As is apparent from Examples 1 to 3, the ethylene vinyl acetate copolymer resin and the crosslinked acrylic particles were mixed with each other at a crosslinked acrylic particle / ethylene vinyl acetate copolymer resin ratio of 0.
A cover tape having an adhesive layer contained in a proportion of 04 or more shows almost no decrease in peel strength even after being left for 5 days in a high temperature and high humidity environment storage. Comparative Example 1 containing no crosslinked acrylic particles,
Comparative Examples 2 and 3 in which the ratio is 0.04 or less even if contained
In, the peel strength is significantly reduced. Particles other than the crosslinked acrylic particles do not have sufficient effect of improving the decrease in peel strength with time in a hot and humid environment as compared with the crosslinked acrylic particles as in Comparative Examples 4 and 5.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 7/02 C09J 123/08 4J040 123/08 B65D 85/38 SN F term (reference) 3E067 AA11 AB41 AC04 BA02A BA24A BB14A BB16A BB25A BB26A BC07A CA11 CA21 EA04 EA12 EA32 EB27 FA09 FC01 3E086 AB02 AC06 AD24 BA04 BA15 BA24 BA35 BB22 BB35 BB52 CA31 3E096 AA06 BA08 CA14 CC01 DA17 DB06 DC03 EA11Y FA07 FA22 FA31 GA07 4F100 AA33 AB21 AB22 AK03B AK25C AK41 AK68C AL01C AR00A AR00B BA03 BA07 BA10A BA10C CA22 CB00C DE01C EH46 EJ38A GB15 GB41 JB12C JG03 JL11C JN01 YY00C 4J004 AA07 AA09 AA10 AA17 AA18 CC03 CD01 FA05 4J040 DA051 DF002 JA09

Claims (8)

[Claims] 1. A cover tape having an adhesive layer containing an ethylene vinyl acetate copolymer resin and crosslinked acrylic particles in a crosslinked acrylic particle / ethylene vinyl acetate copolymer resin ratio of 0.04 or more. 2. The cover tape according to claim 1, comprising at least an outermost layer of a biaxially stretched film, an intermediate layer, and an adhesive layer. 3. The cover tape according to claim 1, wherein the adhesive layer further contains a surfactant and a conductive metal oxide filler. 4. The cover tape according to claim 1, which is an intermediate layer containing a polyolefin resin. 5. The cover tape according to claim 1, which has been subjected to an antistatic treatment. 6. The surface resistance value of the adhesive layer is 10 ⁶ to 10 ¹² Ω /
The cover tape according to any one of claims 1 to 5, which is in a range of □. 7. The cover tape according to any one of claims 1 to 6, which has a haze value of 30% or less. 8. A carrier tape body using the cover tape according to any one of claims 1 to 7.