JP2000345113A - Double coated tape and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare inexpensive cast-type double coated tape enabling a pressure sensitive adhesive layer to adhere on the side of one release liner without exception when torn off and also to provide its production method. SOLUTION: In a double coated tape 1 where an electron beam curing-type pressure sensitive adhesive layer 3 is formed on a release liner 2, adhesive powers between pressure sensitive adhesive layers on one surface 4 and the other surface 5 are made to differentiate by electron beam irradiation. A pressure sensitive adhesive coat is formed by coating a release liner 2 with an electron beam curing-type pressure sensitive adhesive and adhesive powers between pressure sensitive adhesive coats on one surface 4 and the other surface 5 are made to differentiate by electron beam irradiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cast type double-sided tape in which an adhesive is formed on a release liner without using a support, and a double-sided tape.

[0002]

2. Description of the Related Art A double-sided tape is a film adhesive having an adhesive surface on both sides and has features such as good workability which cannot be obtained with a liquid adhesive, and is economical. Widely used.

As a double-sided tape, an adhesive is generally formed on both sides of a support, but from the viewpoint of simplification of the manufacturing process, thinning of the product, etc., a support is not used, and a double-sided tape is formed on a release paper. 2. Description of the Related Art Cast-type double-sided tapes manufactured by applying an adhesive film are manufactured.

[0004] Such a double-sided tape of a cast type is usually formed by rolling an adhesive film formed on a release liner into a roll shape. When both sides have the same adhesive strength, a so-called tearing phenomenon may occur when the tape is used, in which the pressure-sensitive adhesive coating does not adhere to the release liner but adheres to the winding side.

Therefore, conventionally, in order to prevent such a tearing-off phenomenon, different treatments are applied to the front and back surfaces of the release liner to make the releasability of the front and back surfaces different, so that the peeled release liner is always coated with an adhesive film. Like that.

[0006]

However, when such a special release liner is used, the production process of the release liner itself is complicated, and the production cost of the release liner discarded after use is high. The cost of the tape itself will increase.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a cast-type double-sided tape that can always be provided with an adhesive layer on one release liner when peeled off, and that is inexpensive. And a method for producing the same.

[0008]

In order to solve the above problems, the present invention comprises forming an electron beam-curable pressure-sensitive adhesive layer on a release liner, and irradiating the electron beam with one of the pressure-sensitive adhesive layers. Provided is a double-sided tape characterized in that the adhesive force differs between the surface and the other surface, that is, a difference is generated in the adhesive force.

In this case, it is preferable that the adhesive strength of the pressure-sensitive adhesive layer on the release liner side of the pressure-sensitive adhesive layer is larger than the adhesive strength of the other surface. The pressure-sensitive adhesive layer has a thickness of 5 to 100 μm.
m is preferable.

[0010] The present invention also provides a pressure-sensitive adhesive film formed by applying an electron beam-curable pressure-sensitive adhesive on a release liner, and irradiating the film with an electron beam. And a method for producing a double-sided tape, characterized in that the adhesive strength differs between the two sides.

In this case, it is preferable that the pressure-sensitive adhesive film is irradiated with an electron beam from the side of the pressure-sensitive adhesive film so that the pressure-sensitive adhesive force of the pressure-sensitive adhesive film on the release liner side is larger than that of the other surface. Further, the acceleration voltage of the electron beam is preferably 30 to 125 kV. Furthermore, the film thickness of the pressure-sensitive adhesive coating is 5 to 5.
It is preferably 100 μm. Furthermore, it is preferable that the irradiation of the electron beam is performed by a vacuum tube type electron beam irradiation device.

In the present invention, since the adhesive strength of one side and the other side of the pressure-sensitive adhesive layer formed on the release liner is made different, a special release liner having a different releasability on the front and back surfaces is used. It is possible to ensure that an adhesive layer is attached to one of the release liners when peeling off without using a suitable material, and it is possible to obtain a cast-type double-sided tape at a lower cost than before.

In the present invention, since the electron beam is radiated to the electron beam-curable pressure-sensitive adhesive to make the adhesive strength different between one surface and the other surface of the pressure-sensitive adhesive film, the film of the film is coated. It is sufficient to irradiate an electron beam with an appropriate output according to the thickness, and it is very easy to make the adhesive strength differ between one surface and the other surface of the adhesive coating film.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. In the present invention, as shown in FIG. 1, in a cast-type double-sided tape 1 in which an adhesive layer 3 is formed on a release liner 2, the surface 4 of the adhesive layer 3 on the release liner 2 side and the upper surface 5 With different adhesive strength. As shown in FIG. 2, the double-sided tape 1 is wound up into a roll. Therefore, the upper surface 5 of the pressure-sensitive adhesive layer 3 is in close contact with the outer surface 6 of the release liner 2.

In this case, conventionally, since there is no difference in the adhesive strength between the two surfaces of the pressure-sensitive adhesive layer, different treatments are applied to the front and back surfaces of the release liner to prevent the release liner 2 and the pressure-sensitive adhesive layer 3 from tearing apart. In this case, the release properties of the front and back surfaces are changed so that the peeled release liner always has an adhesive layer.

On the other hand, as in the present invention, the pressure-sensitive adhesive layer 3
By making the adhesiveness of the front and back surfaces different from each other, it is possible to eliminate the necessity of subjecting the release liner 2 to a special treatment as in the related art.

In the present invention, the pressure-sensitive adhesive layer 3
As shown in FIG. 3, an electron beam-curable pressure-sensitive adhesive 7 is applied on the release liner 2 to make the adhesive force different between the surface 4 on the side of the release liner 2 and the upper surface 5. The coating film 3a is formed (first step), and then the electron beam 8 is irradiated from the side of the adhesive coating film 3a (second step).

At this time, the output of the electron beam to be irradiated is adjusted so that the electron beam reaches the middle of the adhesive coating 3a. That is, Japanese Unexamined Patent Application Publication No.
By irradiating the pressure-sensitive adhesive coating film 3a with an electron beam at an accelerating voltage having a reaching depth up to a predetermined depth in the thickness direction on the basis of No. 158413, the crosslink density up to that portion is increased. The crosslink density of the upper surface 5 of the adhesive coating 3a is higher than the crosslink density of the surface 4 on the release liner 2 side, and as a result, the adhesive force of the surface 4 on the liner side is higher than the adhesive force of the upper surface 5. be able to.

From the viewpoint of appropriately adjusting the reaching depth, the acceleration voltage of the electron beam is preferably 30 to 125 kV, more preferably 40 to 100 kV. The thickness of the pressure-sensitive adhesive layer 3 is preferably 5 to 100 μm. When the film thickness is less than 5 μm, it is difficult to make a difference in adhesive strength between the two surfaces, and when the film thickness exceeds 100 μm, it becomes too thick as a double-sided tape. A more preferable range of the film thickness is 10 to
70 μm, and an even more preferable range is 20 to 60 μm.
m.

30 to 125 kV (more preferably 40 to 125 kV)
In order to irradiate an electron beam with a low output of 100 kV), it is preferable to use an electron beam irradiation device having a vacuum tube type electron beam irradiation unit. As shown in FIG. 4A, the vacuum tube type electron beam irradiator is provided with a cylindrical vacuum container 11 made of glass, ceramic or metal, and provided inside the container 11 to emit electrons emitted from the cathode. An electron beam generating unit 12 for extracting and accelerating the electron beam as an electron beam;
An electron beam emitting unit 1 that is provided at an end of the device 1 and emits an electron beam
3 and a pin 14 for supplying power from a power supply unit (not shown)
And The electron beam emitting section 13 is provided with a thin-film irradiation window 15. Irradiation window 1 of electron beam emitting unit 13
Reference numeral 5 has a function of transmitting an electron beam without transmitting a gas, and has a flat shape as shown in FIG. Then, the irradiation window 1 is placed on the object to be irradiated arranged in the irradiation room.
The electron beam emitted from 5 is irradiated.

An electron beam irradiation apparatus having such a vacuum tube type electron beam irradiation section is disclosed in US Pat.
No. 4,267, and issued to American International
It is being studied as a Min-EB device by al Technologies (AIT). In this device, 100k
Even at a low accelerating voltage of V or less, the reduction in electron beam transmission power is small, and electron beams can be effectively extracted. This allows the electron beam to act on the coating material on the base material at a low depth.

A drum-type electron beam irradiation apparatus that has been widely used conventionally irradiates an electron beam while constantly evacuating the inside of the drum, and has a substantially large output and a low output area of an acceleration voltage of 100 kV or less. Although it is difficult to properly adjust the output by using the vacuum tube type, it is possible to easily control the acceleration voltage at an acceleration voltage of 100 kV or less by using the vacuum tube type.

In the present invention, as described above, the release liner 2 does not need to have different releasability on both sides.
What has been subjected to the same processing on both sides may be used. As the material of the release liner 2, use paper such as high-quality paper, glassine paper, a laminate of polyethylene on both sides of the paper, or a polyethylene or polyester film coated with a release agent such as a silicone resin on both sides. Can be.

The pressure-sensitive adhesive layer 3 includes a vinyl polymerizable type (cyanoacrylate type, diacrylate type, unsaturated polyester resin type), a condensation type (phenol resin type, urea resin type, melamine resin type) and a polyaddition type (epoxy type). Resin-curable (monomer-type, oligomer-type) resins and the like.

In the above embodiment, the adhesive force of the surface 4 on the liner side is higher than the adhesive force of the upper surface 5 in the adhesive layer 3, but may be reversed. Is performed with the pressure-sensitive adhesive layer side outward, or the electron beam irradiation is performed from the release liner side. Further, the formation of the pressure-sensitive adhesive layer may be performed by an extruder or the like.

[0026]

Embodiments of the present invention will be described below. (Example 1) An electron beam-curable pressure-sensitive adhesive, Biscotac (manufactured by Osaka Organic Chemical Industry Co., Ltd.) was applied on a release liner (SP-PET-B1-50-BU manufactured by Tosero Co., Ltd.) using the same applicator on both sides. Coating to a film thickness of about 40μm
Is formed using an AIT Min-EB electron beam irradiation apparatus at an oxygen concentration of 50 ppm or less and an acceleration voltage of 6
An electron beam was irradiated at 5 kV so as to have three levels of absorbed dose, and the ball tack on one surface (irradiated surface) was measured. Furthermore, the adhesive is stuck on the PET film using a roller,
After removing the release liner, ball tack was measured on two surfaces (side surfaces of the release liner). The film thickness was measured by μ-mate manufactured by Sony Corporation, and the ball tack was measured in accordance with JIS Z 0237, a tilted ball tack. Also, the absorbed dose when irradiating the electron beam is
Far West Technology, FWT
Measured with a 60-00 dosimetry film. Table 1 shows the irradiation conditions of the electron beam at that time, and Table 2 shows the measurement results of the ball tack.

[0027]

[Table 1]

[0028]

[Table 2]

As shown in Table 2, the tackiness was always greater on the two surfaces than on the one surface, and the adhesive force was successfully differentiated between the two surfaces of the adhesive coating film.

Example 2 In this example, an experiment was performed in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive film was changed to 20 μm and the acceleration voltage was changed to 50 kV. Table 3 shows the electron beam irradiation conditions at that time, and Table 4 shows the ball tack measurement results.

[0031]

[Table 3]

[0032]

[Table 4]

As shown in Table 4, as in Example 1, the tackiness was always greater on the two surfaces than on the one surface, and the adhesive force was successfully differentiated between the two surfaces of the adhesive coating film. did.

Example 3 In this example, an experiment was performed in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive coating film was changed to 60 μm and the acceleration voltage was changed to 80 kV. Table 5 shows the electron beam irradiation conditions at that time, and Table 6 shows the ball tack measurement results.

[0035]

[Table 5]

[0036]

[Table 6]

As shown in Table 6, as in Examples 1 and 2,
The tack is always larger on two sides than on one side,
We succeeded in making a difference in the adhesive strength between the two surfaces of the adhesive coating.

Comparative Example 1 Example 1 as a release liner
SP-PET-B1-50- manufactured by TOCELLO CO., LTD.
After forming a 60 μm pressure-sensitive adhesive film on the BU using the same electron beam-curable pressure-sensitive adhesive as in the above example, an electron beam irradiation device EBC-2 manufactured by Nissin High Voltage Co., Ltd.
Pressurizing voltage 150kV, 3m using 00-20-30
A, an electron beam was irradiated under the conditions of an absorbed dose of 30 kGy, and the ball tack was measured in the same manner as in the example. As a result, 1
The ball tack value was 9 on both sides and no difference was observed in the adhesive strength.

Comparative Example 2 Example 1 was used as a release liner.
SP-PET-B1-50 manufactured by TOSERO CORPORATION
Using BU, a pressure-sensitive adhesive containing a pressure-sensitive acrylic resin (pressure-sensitive adhesive Oribain BPS315 manufactured by Toyo Ink Mfg. Co., Ltd.)
6D) and a tolylene diisocyanate derivative-based curing agent (a curing agent BHS85 manufactured by Toyo Ink Mfg. Co., Ltd.)
15) The coating liquid obtained by stirring and mixing 3 parts was dried with a dry film thickness of 40 μm.
After drying in an oven at 90 ° C. for 3 minutes, the same release liner was laminated at a pressure of 3 kgf / cm ² to obtain a double-sided tape. As a result of trying to peel the release liner from this double-sided tape, one surface of the pressure-sensitive adhesive layer appeared five times out of ten times, and the surface of the pressure-sensitive adhesive layer two appeared five times, and a so-called tear-off phenomenon was exhibited. The ball tack was 9 on both sides of the pressure-sensitive adhesive layer.

[0040]

As described above, according to the present invention,
One side of the adhesive layer and the other side have different adhesive strength, so without using a special release liner with different releasability on the front and back, make sure to stick to one side release liner when peeling off A coating film can be applied, and a cast-type double-sided tape can be obtained at a lower cost than before.

Further, since the electron beam-curable pressure-sensitive adhesive is irradiated with an electron beam to make the adhesive strength different between one surface and the other surface of the pressure-sensitive adhesive film, the pressure-sensitive adhesive can be appropriately adjusted according to the thickness of the film. It is only necessary to irradiate the electron beam with an appropriate output, and it is possible to make the adhesive strength of one side of the adhesive coating different from that of the other side very easily.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a structure of a double-sided tape according to the present invention.

FIG. 2 is a side view schematically showing a state where a double-sided tape is wound up.

FIG. 3 is a view for explaining a manufacturing process of the method for manufacturing a double-sided tape according to the present invention.

FIG. 4 is a side view and a bottom view showing an electron beam irradiation unit of an electron beam irradiation apparatus that can be suitably used in the method for producing a double-sided tape according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Double-sided tape 2 ... Release liner 3 ... Adhesive layer 3a ... Adhesive coating film 4 ... Release liner side surface 5 ... Top

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Kunihiko Ozaki 2-13-13 Kyobashi, Chuo-ku, Tokyo F-term in Toyo Ink Manufacturing Co., Ltd. (reference) 4J004 AA01 AA06 AA10 AA12 AA13 AA14 AA15 AB06 CA02 CA04 CA06 CB02 CC02 CD01 DA02 DA04 DB03 EA01 EA05 GA01 GA02

Claims (8)

[Claims] An electron beam-curable pressure-sensitive adhesive layer is formed on a release liner, and the pressure-sensitive adhesive layer has a different adhesive strength between one surface and the other surface by irradiation with an electron beam. Double-sided tape. 2. The double-sided tape according to claim 1, wherein the pressure-sensitive adhesive layer has a pressure-sensitive adhesive force on the release liner side of the pressure-sensitive adhesive layer that is larger than the pressure-sensitive adhesive force on the other surface. 3. The double-sided tape according to claim 1, wherein the pressure-sensitive adhesive layer has a thickness of 5 to 100 μm. 4. An adhesive film is formed by applying an electron beam-curable pressure-sensitive adhesive on a release liner, and irradiating with an electron beam to adhere to one surface and the other surface of the pressure-sensitive adhesive film. A method for producing a double-sided tape, wherein the force is made different. 5. The pressure-sensitive adhesive film, wherein the pressure-sensitive adhesive film is irradiated with an electron beam from the pressure-sensitive adhesive film side, so that the pressure-sensitive adhesive surface of the pressure-sensitive adhesive film on the release liner side is larger than the pressure-sensitive adhesive force of the other surface. Item 6. The method for producing a double-sided tape according to Item 4. 6. The method for producing a double-sided tape according to claim 4, wherein the acceleration voltage of the electron beam is 30 to 125 kV. 7. The pressure-sensitive adhesive film has a thickness of 5 to 100 μm.
The method for producing a double-sided tape according to any one of claims 4 to 6, wherein: 8. The method for producing a double-sided tape according to claim 4, wherein the irradiation of the electron beam is performed by a vacuum tube type electron beam irradiation device.