JP3201507B2 - Cover tape for packaging electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the storage and transportation of electronic components,
A cover tape that can be heat-sealed to a plastic carrier tape formed with a storage pocket, of a package having a function of protecting electronic components from contamination during mounting, aligning and mounting for mounting on an electronic circuit board, and removing the package. is there.

[0002]

2. Description of the Related Art In recent years, transistors such as ICs, transistors, diodes, capacitors, piezoelectric element resistors,
Electronic components for surface mounting, such as a package, consist of a plastic carrier tape formed continuously with embossed pockets that can be stored according to the shape of the electronic component, and a cover tape that can be heat-sealed to the carrier tape. It is packaged and supplied. After peeling off the cover tape of the package, the electronic components of the contents are automatically taken out and surface-mounted on the electronic circuit board. The strength at which the cover tape is peeled off from the carrier tape is called peel-off strength. If the strength is too low, the cover tape comes off when the package is transported, and there is a problem that the electronic components as contents fall off. On the other hand, if the cover tape is too strong, the carrier tape vibrates when the cover tape is peeled off, causing a phenomenon of jumping out of the storage pocket immediately before the electronic component is mounted, that is, a jumping trouble. In addition, when a sample in which the cover tape is sealed with a cover tape or a carrier tape (hereinafter referred to as a taping sample) is stored for a long time under high temperature or high humidity, unwinding of the cover tape becomes difficult, so-called blocking or taping occurs. When the sample was peeled off, the peel-off strength sometimes became stronger or weaker than before storage. There were many cover tapes whose peel-off strength was sensitive to the temperature conditions at the time of taping, and the required peel-off strength could not be easily obtained.

[0003]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention solves the above problem by making the peel-off strength dependent on the sealing temperature.
As a result of earnestly studying to obtain a cover tape with a small sealing effect and a stable sealing property, the polyester,
Via a biaxially stretched film of either polypropylene or nylon and an anchor coat agent layer, the sealant is hydrogenated styrene-
Obtaining that a cover tape comprising a mixture with an isoprene-styrene block copolymer has good properties,
The present invention has been completed.

[0004]

SUMMARY OF THE INVENTION The present invention is a cover tape which can be heat-sealed to a plastic carrier tape in which pockets for accommodating electronic components are formed continuously.
The cover tape is characterized in that the outer layer is a biaxially stretched film of any of polyester, polypropylene and nylon, and the sealant is made of a mixture of polyethylene or polypropylene and a hydrogenated styrene-isoprene-styrene block copolymer. Electronic component packaging cover tape. In a preferred embodiment of the present invention, the biaxially stretched film as the outer layer has a thickness of 5 to 30 μm, the thickness of the sealant is 5 to 30 μm, and the melt flow rate is 10 to 50 g / 10 min. On the other hand, a hydrogenated styrene-isoprene-styrene block copolymer having a melt flow rate of 6 to 250 g / 10 minutes is 10 to 1000.
Parts by weight of the mixture, and the adhesive force between the sealant of the cover tape and the sealing surface of the carrier tape is the seal width.
It is 10 to 120 gr per 1 mm, and the visible light transmittance of the cover tape is 80% or more.

[0005]

The components of the cover tape 1 of the present invention will be described with reference to FIG. 1. The outer layer 2 is a biaxially stretched film made of any one of polyester, polypropylene, and nylon, and has a thickness of 5 to 30 .mu. Film. When the thickness is 5 μm or less, the rigidity is lost and the cover tape is easily cut. If it exceeds 30 μm, the seal becomes too hard and the seal becomes unstable. Sealant 5 has a melt flow rate of 10 to 50
g / 10 minutes polyethylene or polypropylene 1
The melt flow rate is 6 to 250 parts by weight based on 00 parts by weight.
A resin composition comprising a mixture containing 10 to 1000 parts by weight of a hydrogenated styrene-isoprene-styrene block copolymer of g / 10 minutes is formed into a thin film of 5 to 30 μm. With respect to the method of forming the above-mentioned multilayer film, the extrusion lamination method is inexpensive and most desirable from the viewpoint of hygiene.

When the melt flow rate of polyethylene or polypropylene is 50 g / 10 min or more, or the melt flow rate of hydrogenated styrene-isoprene-styrene block copolymer is 250 g / 10 min or more, necking is severe during extrusion lamination. Film cannot be formed.
When the melt flow rate of polyethylene or polypropylene is less than 10 g / 10 min or the melt flow rate of the hydrogenated styrene-isoprene-styrene block copolymer is less than 6 g / 10 min, the film is wound during extrusion lamination. The thickness in the direction is not constant, and a stable product cannot be obtained. When the thickness of the sealant is less than 5 μm, the peel-off strength is easily affected by the shape of the carrier tape when peeled from the carrier tape, and the peel-off strength cannot be stably obtained. Further, after the film is formed, the film is easily cooled, and the adhesion to the outer layer is deteriorated. If it exceeds 20 μm, the heat conductivity at the time of heat sealing deteriorates, and a high temperature is required to obtain an appropriate peel-off strength.

[0007] Polyethylene or polypropylene 100
If the amount of the hydrogenated styrene-isoprene-styrene block copolymer is at least 1,000 parts by weight based on the weight of the film, the film cannot be unwound violently when formed into a film. If the amount is less than 10 parts by weight, an appropriate peel-off strength cannot be obtained. In addition, for the purpose of improving the lamination strength of the outer layer and the sealant, both may be laminated to a thermosetting type anchor coat layer such as an isocyanate type or an imine type via a low density polyethylene layer. The density of the low-density polyethylene layer is 0.91-0.92 g / cm2
It is suitable that the thickness is 5 to 50 μm. When the thickness is 5 μm or less, the peel-off strength is unstable due to the influence of the shape of the carrier tape due to the low elasticity of the cover tape when sealing with the carrier tape. Further, after film formation, the film is easily cooled, and the adhesion to the sealant is deteriorated. If it exceeds 50 μm, heat will not be easily transmitted to the sealant, and the required peel-off strength will not be obtained.

In order to provide an electrostatic effect, an antistatic treatment layer or a conductive layer may be provided on the outer layer side, that is, on the front and back surfaces of the biaxially stretched polyester film. In this case, the sealant resin is formed so that the adhesive strength between the cover tape 1 and the carrier tape 6 is 10 to 120 gr, more preferably 10 to 70 gr per 1 mm of the seal width. If the peel-off strength is lower than 10 gr, there is a problem that the cover tape comes off when the package is transferred, and the electronic components as contents fall off. Conversely, if it is higher than 120 gr, the carrier tape will vibrate when the cover tape is peeled off, causing a phenomenon of jumping out of the storage pocket immediately before mounting the electronic component, that is, a jumping trouble. ADVANTAGE OF THE INVENTION According to this invention, the dependence on sealing conditions is low, and the target performance with little change with time of the peel-off strength by storage environment can be obtained.

The visible light transmittance of the cover tape is 80.
% Or more, preferably 85% or more, so that the internal electronic components sealed in the carrier tape can be visually or mechanically confirmed. If it is lower than 10%, it is difficult to confirm the electronic components inside. When the hydrogenated styrene-butadiene-styrene block copolymer disclosed in JP-A-2-214656 is used instead of the hydrogenated styrene-isoprene-styrene block copolymer, the peel-off strength is lowered and the transparency is remarkably increased. Getting worse.
In addition, the processability during extrusion lamination also deteriorates.

[0010]

EXAMPLES Examples of the present invention are shown below, but the present invention is not limited by these examples. << Examples 1-6 >><< Comparative Examples 1-6 >> A biaxially stretched polyester film having a thickness of 25μ and a thickness of 15
A cover tape having a layer structure shown in FIG. 1 was obtained in which a sealant was formed to a film thickness of 15 μm by extrusion lamination on the polyethylene side of a μ polyethylene laminate product. After slitting the obtained cover tape to a width of 5.3 mm, it was heat-sealed with a carrier tape made of polystyrene having a width of 8 mm, the peel-off strength and the visible light transmittance were measured, and the characteristic evaluation results were shown in Tables 1 and 2. Indicated. * The upper row of the number of the compound shows the weight ratio of the resin contained in the sealant, and the lower row shows the melt flow rate. Heat sealing ^{conditions: 160 ℃ / 1kg / cm 2} /0.1sec. , Seal width 0.4mm × 2 Peel condition: 180 ゜ peel, peel speed 300m
m / min. n = 3

Table 1 Example 1 2 3 4 5 6 Sealant formulation Polyethylene 100 100 100 40 20 10 Polypropylene 100 100 100 15 20 20 SEPS 900 20 800 15 300 400 25 70 30 190 25 25 Visible light transmittance (%) 87 85 93 95 84 82 Initial peel-off strength (g / 1mm width) 66 20 62 15 43 50

Table 2 Comparative Example 1 2 3 4 5 6 Formulation of sealant Polyethylene 100 100 100 40 20 10 Polypropylene 100 100 100 15 20 20 SEBS 5 800 700 100 70 20 20 25 SEPS 2000 5 25 30 Visible light transmittance (%) Not possible 90 93 62 73 50 Initial value of peel-off strength (g / 1 mm width) Not possible 3 2 50 41 16

[0013]

According to the present invention, the peel-off strength is 1 m.
point that can be set arbitrarily in the range of 10 to 120 gr per m,
It is possible to solve the conventional problems that the peel-off strength is largely dependent on the sealing conditions, the problem that changes with time due to the storage environment, and the transparency problem, and obtain a stable peel-off strength.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a layer structure of a cover tape of the present invention;

FIG. 2 is a cross-sectional view showing a state in which the cover tape of the present invention is adhered to a carrier tape and used.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65D 85/86 B32B 27/00 B65D 73/02

Claims (5)

(57) [Claims] 1. A cover tape that can be heat-sealed to a plastic carrier tape in which storage pockets for storing electronic components are continuously formed, wherein the cover tape has an outer layer made of any of polyester, polypropylene, and nylon. A biaxially stretched film, wherein the sealant has a melt flow rate of 10 to 50 g / 10 min. And polyethylene or polypropylene having a melt flow rate of 6 to 250 g / 10 min. Styrene block copolymer is 10
A cover tape for packaging electronic components, wherein the visible light transmittance of the mixture is from 80% to 80% by weight. 2. The thickness of the biaxially stretched film of the outer layer is 5 to 3
2. The cover tape for packaging electronic parts according to claim 1, wherein the sealant has a thickness of 0 μm and a thickness of the sealant is 5 to 20 μm. 3. The cover tape for packaging electronic parts according to claim 1, wherein a low-density polyethylene layer is provided between the outer layer and the sealant. 4. The thickness of the biaxially stretched film of the outer layer is 5 to 3
0μ and the thickness of the polyethylene film of the intermediate layer is 5
The cover tape for packaging electronic parts according to claim 3, wherein the thickness of the sealant is 5 to 30μ. 5. The hydrogenated styrene-isoprene-styrene block copolymer according to claim 1, wherein the molar ratio of styrene in one molecule is 10 to 70%. 4. Cover tape for packaging electronic components according to item 4.