JP3469945B2 - Adhesive tape for splicing release paper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive tape coated with a silicone-based pressure-sensitive adhesive, and more particularly to a pressure-sensitive adhesive tape useful as a paper splicing tape for release paper.

[0002]

2. Description of the Related Art Conventionally, a silicone adhesive tape having a silicone adhesive applied to a substrate has been used for connecting silicone-treated release papers to each other. The connected release paper is processed into a pressure-sensitive adhesive label / sheet by laminating a pressure-sensitive adhesive and a base material on the silicone-treated surface. A silicone-based adhesive tape used for connecting silicone-treated release papers to each other is, for example, as shown in FIG.
One side 10 of the tape substrate 10 as shown in FIG.
a is provided with a silicone adhesive layer 11, and the other tape back surface 10b is treated with a non-silicone release agent effective for the silicone adhesive used for the tape itself, or is not treated. It is known that the silicone adhesive layer 11 and the tape back surface 10b are in direct contact with each other without a release liner and in a tape shape. When the above silicone-based adhesive tape is used as a splicing tape for release paper, the back surface 10b has no releasability against general adhesives such as acrylic and rubber adhesives used for adhesive labels and sheets. In the production of pressure-sensitive adhesive labels / sheets, etc., with conventional release paper connected with silicone adhesive tape, when acrylic adhesive or rubber adhesive is coated on the release paper, it will be separated from the silicone adhesive tape. It had a defect that peeling failure occurred on the back surface of the tape at the paper connection point.

Therefore, as a paper splicing tape in which the back surface of a silicone-based adhesive tape and an adhesive layer such as an adhesive label / sheet do not cause peeling failure, it is found in JP-A-58-27333 or JP-A-58-180258. Such silicone-based adhesive tapes have been proposed. This tape is shown in Figure 3.
As shown in FIG. 2, a silicone-based adhesive layer 21 is provided on one surface 20a of the tape substrate 20, and a silicone-based release agent layer 22 is provided on the opposite surface 20b thereof, and the silicone-based adhesive layer 21 and the tape back surface 20b of the tape are provided. The release liner 23 coated with a non-silicone release agent having releasability with respect to the silicone-based adhesive is attached to the silicone-based pressure-sensitive adhesive layer 21 so that the silicone-based release agent layer 22 and the silicone-based release agent layer 22 do not contact each other. It is configured as a tape shape with a mated release liner.

Furthermore, as a silicone-based adhesive tape which can be used for connecting a release paper and has a performance in which the connection point does not cause a peeling failure during the production of an adhesive label or sheet, etc. 5-2223
Silicone pressure-sensitive adhesive tapes such as those found in No. 45 have been proposed. The structure of this tape is such that a silicone-based pressure-sensitive adhesive layer is provided on one side of a tape base material and a silicone-based release agent layer is provided on the other side, and the silicone-based release agent layer is directly contacted with the silicone-based pressure-sensitive adhesive layer. In the adhesive tape, the silicone release agent layer has a shear modulus of 1 × 10 ⁷ dyn / cm ² to 6 × 10 ⁷ dy according to JIS K7213.
The tape is formed of a release agent containing dimethylpolysiloxane as a main component in the range of n / cm ² , and the silicone-based adhesive layer is formed of a dimethylpolysiloxane-based silicone adhesive.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the silicone pressure-sensitive adhesive tape (FIG. 3) described in No. 333 or Japanese Utility Model Laid-Open No. 58-180258, first, when the silicone-treated release paper is connected, the release liner 23 attached to the tape is first peeled off to remove the silicone. The system pressure-sensitive adhesive layer 21 is attached to a silicone-treated release paper surface for connection. In this case, since the back surface 20b of the connecting tape is treated with silicone, even if an acrylic adhesive or a rubber adhesive is coated on the release paper at the time of manufacturing an adhesive label, a sheet, or the like, no peeling failure occurs at the connection point. Absent. When the silicone-based release agent layer 22 and the silicone-based pressure-sensitive adhesive layer 21 of this tape are brought into contact with each other, the release agent layer and the pressure-sensitive adhesive layer are firmly adhered to each other, making it impossible to develop the tape.
Release liner required. However, it is very troublesome and the work is difficult to remove the release liner when using the tape. Further, the release liner attached to the silicone-based pressure-sensitive adhesive layer as described above generally has an uneven surface shape due to embossing or the like, and in this case, the silicone-based pressure-sensitive adhesive surface which is in contact is also It has irregularities and has a drawback that the adhesive strength to silicone-treated release paper is poor.

On the other hand, in the pressure-sensitive adhesive tape described in JP-A-5-222345, the tape developability is very good, but the silicone-based release agent of the pressure-sensitive adhesive tape peels when exposed to air. There is a problem that the property is lost (hereinafter referred to as "exposed air"). The outermost release agent layer of the silicone adhesive tape is always exposed to the outside air,
When acrylic adhesive or rubber adhesive is applied to release paper connected using this layer, peeling failure may occur on the back surface of the tape at the connection point of the silicone adhesive tape and release paper. There is a nature.

[0007]

As a result of various studies to solve the above-mentioned problems, the present inventors have found that a silicone-based release agent containing an addition type polyorganosiloxane having a specific alkenyl group is a silicone-based adhesive. It has been found that the release agent is effective for both adhesives and rubber-based adhesives and has a well-balanced performance. That is, an object of the present invention is to splice a release paper having a release agent layer containing an addition type polyorganosiloxane having an alkenyl group and an addition type dimethylpolysiloxane silicone adhesive layer.
The purpose of the present invention is to provide a pressure-sensitive adhesive tape. Release paper of the present invention
In the adhesive tape for paper splicing , the silicone adhesive layer is provided on one surface of the tape base material, and the release agent layer is provided on the opposite surface, and the release agent layer is directly contacted with the silicone adhesive layer. In a pressure-sensitive adhesive tape for paper splicing of release paper, the release agent layer comprises a silicone release agent containing an addition-type polyorganosiloxane having an alkenyl group having 4 or more carbon atoms as a functional group, and the silicone pressure-sensitive adhesive layer is It consists of an addition type dimethylpolysiloxane silicone adhesive.

The adhesive tape for splicing release paper of the present invention is
As shown in FIG. 1, the tape substrate 1, its one side 1
Silicone pressure-sensitive adhesive layer 2 provided on a and the opposite surface 1
It consists of the silicone-based release agent layer 3 provided in b. As the tape substrate 1 in the present invention, a PET film, an OPP film, a polyethylene film, a polyetherimide film, a polyimide film, an aramid paper or a laminated body of these, and other various synthetic papers can be used. As the silicone-based pressure-sensitive adhesive applied to the tape substrate 1 to form the silicone-based pressure-sensitive adhesive layer 2, dimethylpolysiloxane-based silicone pressure-sensitive adhesive obtained by curing dimethylpolysiloxane as a gum component with a platinum-based catalyst. Agents are used, and typical ones are
SD-458 made by Toray Dow Corning Silicone
0 (trade name) is known. The coating amount of the silicone adhesive in ^20g / ^{m 2 ~200g} / m 2 solids, preferably it is 50 g / ^m about ² solids. The silicone adhesive may be applied by a conventionally known method, for example, comma coating or roll coating.

The release agent coated on the back surface 1b of the tape substrate 1 to form the release agent layer 3 is a silicone containing an addition type polyorganosiloxane having an alkenyl group having 4 or more carbon atoms as a functional group. It consists of a system release agent. For example, an addition type polyorganosiloxane containing an alkenyl group having 4 or more carbon atoms as a functional group is represented by the following formula:

[0010]

[Chemical 1]

It is preferred to have In the formula, n is preferably 2 to 8, and more preferably 4 (hexenyl group). Further, x and y are appropriately selected in consideration of the peeling performance of the adhesive tape and the suitability for coating.
As the other component of the silicone-based release agent, a polyorganosiloxane having a silicon atom-bonded hydrogen atom, a polyorganosiloxane having an alkenyl group and a silicon atom-bonded hydrogen atom, and a polyorganosiloxane having no functional group are appropriately selected. Usually, a platinum-based catalyst is added and heated to form a cured film. The vinyl group-containing addition-type dimethylsiloxane-based release agent that has been conventionally used cannot obtain releasability from an acrylic adhesive or a rubber adhesive after being exposed to the outside air. The silicone release agent may be applied by a conventionally known method. Examples thereof include gravure roll coating, bar coating and air knife coating.

[0012]

When the pressure-sensitive adhesive tape for splicing release paper according to the present invention is used to connect the release paper and the release paper, the back surface of the tape at the connection point is treated with the above-mentioned alkenyl group-containing polyorganosiloxane silicone release agent. Therefore, since it has releasability with respect to the acrylic adhesive or the rubber adhesive used for the adhesive label / sheet, the acrylic or rubber adhesive is placed on the release paper at the time of manufacturing the label / sheet. Even if it is applied, no peeling defect occurs at the tape connecting portion. Further, a paper splice of the release paper of the present invention
The adhesive tape for use is limited to the combination of the addition-type dimethylpolysiloxane-based silicone adhesive and the silicone-based release agent containing the alkenyl group-containing polyorganosiloxane, and the back surface of the tape directly contacts the silicone-based adhesive. Since the conventional adhesive tape with release liner had to be peeled off before use, the silicone-based adhesive surface was exposed and it had to be attached to release paper. for,
In the tape of the present invention, since the silicone adhesive is exposed at the same time as the tape is developed, the workability is improved simply by sticking it on the release paper. Further, it has a feature that it is not necessary to dispose of the release liner.

[0013]

EXAMPLES Next, the present invention will be described based on Examples and Comparative Examples.
The adhesive tape for joining the release paper will be described. Example 1 A silicone-based release agent containing a hexenyl group-containing polyorganosiloxane on one side of a 25 μm-thick PET film (manufactured by Toray Dow Corning Silicone, trade name:
LTC 750A) was applied and heat-cured at 150 ° C. for 60 seconds to form a silicone-based release agent layer having a thickness of about 1.5 μm. Next, a dimethylpolysiloxane-based silicone pressure-sensitive adhesive (Toray Dow Corning Silicone, trade name: SD-4580) was applied to the opposite surface of the PET film and heat-cured at 130 ° C. for 2 minutes to give a thickness of about 50 μm. A silicone-based pressure-sensitive adhesive layer was formed, and a single-layer silicone pressure-sensitive adhesive tape was prepared by directly contacting the silicone-based release agent layer and the silicone-based pressure-sensitive adhesive layer.

Comparative Example 1 The silicone-based release agent of Example 1 was used as a dimethylpolysiloxane-based release agent having a vinyl group as a functional group (Toray Dow Corning Silicone Co., Ltd., trade name: SRX211). An adhesive tape was prepared according to Example 1. Regarding the adhesive tapes obtained in the above Examples and Comparative Examples, after curing, the developability of the tape, the adhesiveness of the tape to commercially available release paper, and the commercially available acrylic solvent type that is typically used for the tape back surface and the adhesive label or sheet The peelability from the adhesive was tested and evaluated, and the results are summarized in Table 1 below.

[0015]

[Table 1]

The performance evaluation test in Table 1 was conducted as follows. * 1 Evaluated by the peeling force between the tape backside adhesive tape and the adhesive layer (deformation speed 1 m / min, peel angle 180 ° peel) * 2 Adhesive adhesive tape between tape and commercial release paper (KP manufactured by Lintec Co., Ltd.
-8) was pressure-bonded with a 2 kg roller, and evaluated by the adhesive force after leaving for 30 minutes (deformation speed 0.3 m / min, peeling angle 18
Peel on the 0 ° tape side. * 3 Releasable from the commercial acrylic adhesive on the back of the tape after exposure to the outside air. Made by
Product name: BPS-5127) coated (30 μm dry), PET 50 μm And the peeling force
Measurement (deformation speed 10m / min, peeling angle 180 °
PET 50μm side peeled)

As is clear from Table 1, the peel strength of the adhesive tape obtained in Example 1 was 460 g / 20 mm (deformation speed = 1 m / min), and the tape could be developed. The exposure to the outside air was also good. However, in the pressure-sensitive adhesive tape obtained in Comparative Example 1, the pressure-sensitive adhesive and the release agent were firmly adhered to each other and could not be peeled off, and the exposure to the outside air was also poor.

[0018]

EFFECTS OF THE INVENTION According to the adhesive tape for splicing release paper of the present invention, the back surface of the tape is subjected to a release treatment with a silicone-based release agent having excellent exposure to the outside air. No peeling trouble at the paper connection,
Further, since the tape does not require a release liner, it has an effect that the work is simple and the disposal of the liner is not troublesome.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of an adhesive tape for paper piecing of release paper of the present invention.

FIG. 2 is a diagram showing a structure of a conventional adhesive tape.

FIG. 3 is a diagram showing the configuration of another conventional adhesive tape.

[Explanation of symbols]

1 Tape base material 1a One side 1b opposite side 2 Silicone adhesive layer 3 Silicone release agent layer 10 Tape base material 10a one side 10b back 11 Silicone adhesive layer 20 Tape base material 20a one side 20b back 21 Silicone adhesive layer 22 Silicone release agent layer 23 Release liner

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C09J 7/02

Claims (3)

(57) [Claims] 1. A silicone-based pressure-sensitive adhesive layer provided on one surface of the tape base, the release agent layer on the opposite surface is provided that, the release of the release agent layer is brought Taise' directly silicone adhesive layer
In a pressure-sensitive adhesive tape for paper splicing , the release agent layer comprises a silicone release agent containing an addition-type polyorganosiloxane having an alkenyl group having 4 or more carbon atoms as a functional group, and the silicone pressure-sensitive adhesive layer is added. A pressure-sensitive adhesive tape for splicing release paper, characterized by comprising a dimethylpolysiloxane-based silicone adhesive. 2. The addition-type polyorganosiloxane containing an alkenyl group has the following formula: (Wherein n = 2 to 8), the release paper according to claim 1
Adhesive tape for paper splicing . 3. The adhesive tape for splicing release paper according to claim 2, wherein the alkenyl group is a hexenyl group.