JP2000327024A - Cover tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cover tape wherein a difference between a maximum value and a minimum value of the peeling strength is small at the time of a peeling of the cover tape when being actually installed, and which can be stably peeled, and does not generate a cut of the cover tape. SOLUTION: This cover tape 1 is bonded to a carrier tape wherein recess sections in which an electronic part is housed are formed, and covers the recess sections. A base material layer 2 comprises an external layer 2a which is a biaxially drawn film layer, and an internal layer 2b of a thermoplastic polyurethane based resin layer. A bonding layer 3 includes an inter-layer peeling layer 3a comprising a thermoplastic polyurethane based resin which is provided on the surface of the internal layer 2b, and an adhesive layer 3b which can be peeled from the inter-layer peeling layer 3a and can be bonded to the carrier tape. The tensile strength of the inter-layer peeling layer 3a is 25 to 50 MPa and is lower than the tensile strength of the internal layer 2b.

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 covering the upper surface of a carrier tape used for storing and transporting fine parts (hereinafter simply referred to as parts) such as various electronic parts and precision equipment parts. Things.

[0002]

2. Description of the Related Art In recent years, packaging materials comprising a carrier tape and a cover tape have been used for storing, transporting, and mounting semiconductor components. The carrier tape has a concave portion corresponding to the shape of each component, and the cover tape is a cover material for the concave portion. Then, after the components are stored in the recesses, the cover tape is sealed on the carrier tape using a heat seal or an adhesive in order to prevent and protect the components from falling off. The cover tape is peeled off from the carrier tape at the time of component mounting, and the component removed from the recess is attached to the substrate. With this mounting technology, the mounting speed has been significantly increased year by year for the purpose of improving production efficiency.
The cover tape is peeled off from the carrier tape by a strong tension in a shorter time, and a larger load is applied to the cover tape than before.

[0003] At present, the structure of cover tapes that are distributed in the market is mainly composed of a single layer of base material and an adhesive layer for heat sealing to a carrier tape. As an adhesive used for such a heat seal type cover tape, a polyester resin, a polyurethane resin, a polyacrylic resin, a styrene resin, and an ethylene vinyl acetate resin are generally used. These adhesives are required to be able to adhere to the carrier tape with an appropriate adhesive strength, to prevent the stored components from falling off during transportation, and to be smoothly separated from the carrier tape during mounting.

[0004]

However, the peel strength required when the cover tape is peeled is very different from the adhesive strength of general packaging materials, and a very low value is required. In order to meet this demand, conventionally, a method of inhibiting the adhesive force of the adhesive, for example, adding a non-adhesive material to the adhesive or partially applying the adhesive has been performed. Although it is possible to obtain a predetermined peel strength by these methods, the difference between the maximum value and the minimum value of the peel strength (hereinafter, referred to as rash) may increase depending on the bonding site. This is a phenomenon that occurs because the adhesive tape is continuous, while the recessed and unmolded portions of the carrier tape are alternately arranged. There is a rampage inside.

[0005] When the carrier tape becomes unsteady, the stored parts dance, so that the parts are turned over at the part pick-up part, that is, the pickup part, or jump out of the concave parts, resulting in a pick-up defect that cannot be mounted. In addition, the carrier tape flaps and meanders due to the swelling, so that the cover tape is scratched in the mounter cassette, causing "cover tape breakage" and "delaminating", which causes peeling between the cover tape layers. , Resulting in defective parts removal. Each of these causes a reduction in the operating rate of the mounting machine.

[0006] Furthermore, with the increase in mounting speed, a large burden on the cover tape at the time of mounting has to be dealt with by a single-layer base material and an adhesive layer having lower mechanical strength than the base layer by giving priority to adhesiveness. I couldn't keep up, "Cover tape out", "Derami"
Failure to take out components frequently occurs due to factors such as this, and this is a factor that lowers the operating rate of the mounting machine.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a cover tape that can reduce peeling from a carrier tape, can be stably peeled off, and does not cause tape breakage.

[0008]

The present invention solves the above-mentioned problems by the following means. That is, the invention according to claim 1 includes a biaxially stretched film layer and a thermoplastic polyurethane-based resin layer in a cover tape adhered to a carrier tape having a storage recess for storing an electronic component and covering the storage recess. A base layer, provided on the surface of the thermoplastic polyurethane-based resin layer, a release layer containing a thermoplastic polyurethane-based resin, provided on the surface of the release layer, can be peeled from this release layer, and, An adhesive layer capable of adhering to a carrier tape, wherein a tensile strength of the release layer is lower than a tensile strength of the thermoplastic polyurethane-based resin layer.

According to a second aspect of the present invention, in the cover tape according to the first aspect, the release layer has a tensile strength of 25M.
A cover tape having a pressure of Pa to 50 MPa.

[0010]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a sectional view of a cover tape according to an embodiment of the present invention, and FIG.
FIG. 4 is a cross-sectional view showing a state in which the cover tape according to the embodiment of the present invention is bonded to a carrier tape. FIG.
FIG. 3 is a cross-sectional view showing a state in which the cover tape according to the embodiment of the present invention has been peeled off from the carrier tape.

As shown in FIG. 2, the cover tape 1 is heat-sealed to a flange surface 9 of a carrier tape 8 in which a concave portion 7 for accommodating the component 6 is continuously formed in a flow direction. It is a member that covers and seals. As shown in FIG. 1, the cover tape 1 includes a base layer 2 composed of two layers, an outer layer 2a and an inner layer 2b, a delamination layer 3a, and an adhesive layer 3.
b). Delamination layer 3a
Is made of a thermoplastic polyurethane resin having a tensile strength (JISK 7311) of 50 MPa or less, and the adhesive layer 3b is made of a matrix of barium sulfate particles coated with conductive tin oxide and a thermoplastic acrylic resin. Have been. The adhesive layer 3b is, as shown in FIG.
When the cover tape 1 is peeled off from the upper flange surface 9 and the concave portion 8 is taken out from the component 6, a part is left on the flange surface 9.

The base layer 2 has an outer layer 2a made of a biaxially stretched polymer film and an inner layer 2b in which at least one layer of a thermoplastic polyurethane resin is laminated on the adhesive layer side. Examples of the biaxially stretched film used for the outer layer 2a of the base material include a biaxially stretched film such as polyester, polyamide, and polyolefin, and a film in which a coating agent such as a conductivity imparting agent or a primer is applied to the surface of the film. . Among these, in consideration of heat resistance, transparency and rigidity, a biaxially stretched polyester film or a biaxially stretched polyester film coated with the above coating agent is desirable. The thickness of the outer layer 2a of the substrate is 5 to 50 μm.
If m is less than 5 μm, the rigidity is insufficient, and if it exceeds 50 μm, the flexibility is lacking.

The thermoplastic polyurethane-based resin used for the inner layer 2b of the base material includes one containing one-component polyurethane, two-component curable polyurethane or thermoplastic polyurethane as a main component. This polyurethane resin is synthesized by reacting a prepolymer, a diisocyanate and a chain extender. As a prepolymer, polyester, polyether, polycarbonate or a copolymer thereof is used, and as a chain extender, an active hydrogen compound such as a diol or a diamine is used.

The one-pack type polyurethane is obtained by dissolving a soluble thermoplastic polyurethane in an organic solvent, and is essentially included in the thermoplastic polyurethane. This thermoplastic polyurethane is a linear polymer in which diisocyanate groups and active hydrogen functional groups are mixed in equal amounts. (In the following text, one-component polyurethane and thermoplastic polyurethane will be distinguished from each other.)

[0015] Commercially available thermoplastic polyurethanes are provided in powder or pellet form, can be formed into any shape by heat melting, and are produced by extrusion or calendering to obtain sheet-like products. The other one-component polyurethane is obtained by dissolving a thermoplastic polyurethane in an organic solvent such as toluene, dimethylformamide, and methyl ethyl ketone, and is a material suitable for obtaining a sheet by coating.

The two-part curable urethane is composed of a polymer in which an active hydrogen functional group is blended more than a diisocyanate group,
This is a type of polyurethane obtained by mixing a diisocyanate or a chain extender immediately before molding and curing almost simultaneously with molding. This two-part curable urethane is a two-part liquid material composed of a prepolymer, a diisocyanate, a urethane oligomer (including an organic solvent solution of the above-mentioned thermoplastic urethane) and a chain extender. Suitable to get.

The thermoplastic polyurethane resin used for the inner layer 2b of the substrate has a tensile strength (JIS K 731).
1) exceeding 50 MPa is used, and 50 MPa
If it is less than, the load at the time of mounting at a high speed cannot be sufficiently coped with, and the cover tape may be broken. The thickness range is 5 to 50 μm. If the thickness is less than 5 μm, physical properties as a base material cannot be expected. If the thickness exceeds 50 μm, heat conduction is poor and poor sealing is caused, so that the thickness is particularly preferably 20 to 40 μm.

Base material 2 comprising outer layer 2a and inner layer 2b
As a method of laminating a polyurethane film on a biaxially stretched film, for example, a biaxially stretched polyethylene terephthalate film, an extrusion laminating method in which a polyurethane resin melted in the biaxially stretched film is laminated simultaneously with the formation of a film, or There is a method of dissolving a polyurethane resin in a solvent such as toluene or ethyl acetate on a stretched film, coating the film, and laminating the film, but is not particularly limited in the present invention. In order to firmly adhere the biaxially stretched film to the polyurethane resin, an isocyanate-based, amine-based, imine-based anchoring agent may be used, or the biaxially stretched film may be subjected to corona treatment.

The adhesive layer 3 of the present invention has a higher tensile strength (J) than the thermoplastic polyurethane resin used for the inner layer 2b of the base material.
An interlayer release layer 3a made of a polyurethane resin having a low IS K 7311) and an adhesive layer 3b made of a mixture of barium sulfate particles coated with conductive tin oxide and a thermoplastic acrylic resin. The method of laminating the delamination layer 3a and the adhesive layer 3b on the substrate 2 is as follows.
Any coating method using an inexpensive and simple gravure coat, a comma coater or the like can be adopted.

The thermoplastic polyurethane resin used for the delamination layer 3a may be one containing one-pack polyurethane, two-pack curing polyurethane or thermoplastic polyurethane as a main component, and has a tensile strength (JIS K 7311).
Is lower than the polyurethane resin of the inner layer 2b of the base material,
When the pressure exceeds 50 MPa, the peel strength becomes large, and the occurrence of pick-up failure and “cut cover tape” due to the dance of the stored components 6 increases, and the operating rate of the mounting machine decreases. Lower.
If the pressure is lower than 25 MPa, the peel strength increases due to an increase in the tackiness of the polyurethane resin, and a mounting failure such as a pick-up failure due to a part dance or a cover tape breakage occurs. If the thickness of the delamination layer 3a is 0.5 μm or less, the sealing is insufficient, and if it exceeds 15 μm, the sealing is clearly excessive, and sufficient sealing properties can be obtained without increasing the thickness. To 15 μm, particularly preferably 0.5 to 10 μm.

The thermoplastic acrylic resin used for the adhesive layer 3b together with the barium sulfate particles coated with conductive tin oxide is usually polymethyl methacrylate,
It is a soluble material mainly composed of polyethyl methacrylate, polybutyl methacrylate and the like. The glass transition temperature varies depending on the combination of the above resins, the introduced functional groups, and the molecular weight, etc., and includes various grades having different thermal characteristics and substances.

An adhesive layer 3 made of barium sulfate particles coated with a thermoplastic acrylic resin and conductive tin oxide
For the formation of b, the mixture of the two is used as an ink and
b. First, a thermoplastic acrylic resin is dissolved in a solvent such as toluene or ethyl acetate to a concentration of 5 to 50%, and barium sulfate particles coated with conductive tin oxide are dispersed in the solution. In this case, if the amount of the barium sulfate particles coated with the conductive tin oxide is less than 150 parts by weight with respect to 100 parts by weight of the thermoplastic acrylic resin, the conductivity is insufficient, and if it exceeds 400 parts by weight, it becomes brittle. Therefore, 150 to 400 parts by weight is desirable. If the thickness of the adhesive layer 3b is less than 0.3 μm, the sealing is insufficient, and if it exceeds 3 μm, it is clearly excessive, and sufficient sealing properties can be obtained without increasing the thickness.
In particular, the thickness is preferably 0.5 to 1 μm.

A cover tape 1 according to an embodiment of the present invention
Has tear resistance inside the outer layer 2a of the biaxially stretched film,
By providing the inner layer 2b having excellent tensile strength, it is possible to prevent the cover tape from breaking due to a load during high-speed mounting. Also, an interlayer release layer 3a having flexibility and relatively low mechanical strength such as tensile strength is provided between the adhesive layer 3b and the base material layer 2 which are heat-sealed to the carrier tape 8; The adhesive layer 3 was firmly adhered to the base material layer 2, and the structure was such that peeling proceeded due to interface destruction between the adhesive layer 3 b and the interlayer peeling layer 3 a. As a result, it is possible to obtain a stable peel strength with less swelling. Further, by using a thermoplastic acrylic resin to which a conductive filler is added for the adhesive layer 3b,
The cover tape 1 having transparency and conductivity can be obtained.

[0024]

Next, the present invention will be described with reference to examples.
The present invention is not limited to the description of this embodiment.

[0025]

[Table 1]

PET shown in Table 1 is biaxially stretched polyethylene terephthalate, and TPU is a thermoplastic polyurethane resin. As shown in Table 1, a thermoplastic polyurethane was extruded on a biaxially stretched polyethylene terephthalate film having one surface coated with an anchor coating agent by extrusion lamination. Next, a solution of a thermoplastic polyurethane resin and polymethyl methacrylate 100
300 parts by weight of barium sulfate (average particle size: 0.4 μm) mixed and dispersed with conductive tin oxide was applied (laminated) to each part by weight by gravure coating to obtain a cover tape. Table 1 also shows the tensile strength and thickness of the thermoplastic polyurethane resin.

After slitting the obtained cover tape to a width of 21.0 mm, a carrier tape made of polystyrene and a taping machine VN3200 (Vanguard Taping, product name)
Using a sealing pressure of 3 kg, a sealing temperature of 170 ° C.,
Heat sealing was performed under the conditions of a sealing time of 0.4 seconds and a sealing width of 0.5 mm × 2, and both were peeled at a peeling speed of 300 mm / min and 50,000 mm / min, and peel strength and presence or absence of tape breakage were measured. Table 1 shows the results.
Shown in

As shown in Table 1, in Examples 1 to 5, the tensile strength of the delamination layer 3a was set to 30 MPa to 45 MPa, and the tensile strength of the delamination layer 3a was smaller than that of the inner layer 2b. Things. In this case, there was no breakage of the cover tape at the time of high-speed peeling, and the difference between the maximum value and the minimum value of the peeling strength was 9 g or less, and the rash was small.
On the other hand, in Comparative Example 1, the inner layer 2b shown in FIG. 1 was omitted, and the delamination layer 3a was provided on the outer layer 2a. Roughness was greater than in Examples 1 to 5. In Comparative Example 2, the interlayer peeling layer 3a shown in FIG. 1 was omitted and the adhesive layer 3b was provided on the inner layer 2b. As shown in Table 1, there was no breakage of the cover tape at the time of high-speed peeling. The rug was quite big. In Comparative Example 3, the tensile strength of the inner layer 2b and the delamination layer 3a shown in FIG.
As shown in, there is a break in the cover tape at the time of high-speed peeling,
It was big.

[0029]

As described above in detail, according to the present invention, in a cover tape which is adhered to a carrier tape having a housing recess for housing an electronic component, and covers the housing recess, a biaxially stretched film layer is provided. A base layer containing a thermoplastic polyurethane resin layer, a release layer provided on the surface of the thermoplastic polyurethane resin layer and containing a thermoplastic polyurethane resin, and a release layer provided on the surface of the release layer and peeled off from the release layer And an adhesive layer capable of adhering to the carrier tape, wherein the tensile strength of the release layer is lower than the tensile strength of the thermoplastic polyurethane resin layer. The ruggedness becomes smaller,
Peeling can be performed stably, and breakage of the cover tape can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cover tape according to an embodiment of the present invention.

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

FIG. 3 is a cross-sectional view showing a state in which the cover tape according to the embodiment of the present invention has been peeled off from the carrier tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cover tape 2 Base layer 2a Outer layer 2b Inner layer 3 Adhesive layer 3a Delamination layer 3b Adhesive layer 6 Parts 7 Recess 8 Carrier tape 9 Flange surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E067 AA11 AB41 AB49 AC04 AC11 BA26A BB14A BB25A BC07A CA30 EA12 EB27 FA01 FA09 FC09

Claims (2)

[Claims] 1. A cover tape adhered to a carrier tape having a storage recess for storing an electronic component and covering the storage recess, the cover tape comprising a base layer including a biaxially stretched film layer and a thermoplastic polyurethane-based resin layer. , Provided on the surface of the thermoplastic polyurethane resin layer,
A release layer containing a thermoplastic polyurethane resin; and an adhesive layer provided on a surface of the release layer and peelable from the release layer, and capable of adhering to the carrier tape. The cover tape, wherein the strength is lower than the tensile strength of the thermoplastic polyurethane resin layer. 2. The cover tape according to claim 1, wherein the release layer has a tensile strength of 25 MPa to 50 MPa.