JPH10338852A - Production of pressure-sensitive silicone adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process used for producing a pressure-sensitive silicone adhesive tape which, when it is in the form of a winding, can be easily rewound with a suitable developing force and has high coating productivity by using a back-treating agent having a high adhesion to a substrate and the smoothness of a coated surface. SOLUTION: A layer of an alkyl isocyanate grafted saponified vinyl acetate (co)polymer or of a long-chain alkyl isocyanate grafted ethyleneimine (co)polymer is formed on one surface of a synthetic film base material, and silicone anchor agent is applied to the other surface. The film is one wound in a roll and cured, and a pressure-sensitive silicone adhesive layer is laminated on the surface of the anchor agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a silicone-based pressure-sensitive adhesive tape.

[0002]

2. Description of the Related Art Silicone pressure-sensitive adhesives have high adhesive strength,
In addition, because of its excellent adhesive properties such as excellent heat resistance, chemical resistance, water resistance, and aging resistance, it has been conventionally used for bonding to applications that require heat resistance and difficult-to-adhere surfaces. Has been used for However, since the silicone pressure-sensitive adhesive itself is expensive, the selectivity of the substrate to be used is strong, and the affinity between these substrates and the silicone-based pressure-sensitive adhesive is generally extremely low. When used, it is used only when it causes problems.

In addition, when the use of an acrylic pressure-sensitive adhesive causes problems, a silicone-based anchoring agent is also used in a silicone-based pressure-sensitive adhesive tape in order to ensure adhesion between the substrate and the silicone-based pressure-sensitive adhesive. Above all, when the anchor agent application process and the adhesive application process are separated, especially when the anchor agent is transferred to the back surface of the base material, as a result, when the obtained adhesive tape is peeled off from the end, blocking and heavy development are caused. However, to prevent this, it is necessary to sufficiently cure the anchoring agent, which requires a sufficient heating temperature and time for the curing, and is extremely productive. Was a bad thing. That is, for certain types of silicone anchors,
In order to prevent back transfer, for example, a heating temperature and time for curing are required to be 120 ° C. or more and 5 minutes or more.

[0004] After the anchor agent coating step is completed, it is sufficient that the silicone-based pressure-sensitive adhesive can be processed without winding the coated product into a roll, but in this case, there is a restriction that the production equipment becomes large. If the production equipment cannot apply the silicone adhesive without winding the coated product into a roll, once the coating of the anchor agent has been completed, once the coated product is wound into a roll and the base material before the adhesive process is applied. There is a need to produce as a counterproduct.

[0005] In order to reduce the developing force of the silicone-based pressure-sensitive adhesive tape and to optimize the use thereof, for example, Japanese Patent Application Laid-Open No. 2-11681 discloses a low-molecular-weight as a back surface treating agent for a silicone-based pressure-sensitive adhesive tape. Coating thickness of polyolefin polyol and polyisocyanate compound 10-1
It is disclosed to be used at 00 μm. However, it is extremely uneconomical to apply an extremely thick coating of the back surface treatment agent as 10 to 100 μm, which increases the cost of the silicone-based pressure-sensitive adhesive tape.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above facts, and has as its object
By using a back surface treatment agent that has high adhesion to the substrate and smoothness of the coated surface, the adhesive tape can be easily rewound from the wound adhesive tape with an appropriate developing force, and high coating production can be achieved. An object of the present invention is to provide a method for producing a silicone-based pressure-sensitive adhesive tape having properties.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a method for forming a layer of a modified alkyl isocyanate graft of a saponified vinyl acetate (co) polymer or a modified long chain alkyl isocyanate of an ethyleneimine (co) polymer on one surface. Applying a silicone-based anchoring agent to the other surface of the synthetic resin film substrate on which is formed, temporarily winding in a roll shape, curing, and then laminating a silicone-based pressure-sensitive adhesive layer on the anchoring agent-applied surface. A method for producing a silicone-based pressure-sensitive adhesive tape characterized by the following.

[0008] The synthetic resin film substrate used in the present invention is not particularly limited and may be appropriately selected and used depending on the application. Examples thereof include polyethylene terephthalate (PET), polycarbonate, polysulfone, and polysulfone. Films made of arylate, polyethersulfone, polypropylene and the like can be mentioned. These synthetic resin films may be composed of a single film, or may be composed of a composite film in which two or more synthetic resin films are laminated. It may include a fibrous or other reinforcing material.

An alkyl isocyanate graft-modified product of a saponified vinyl acetate (co) polymer formed on one surface of the synthetic resin film substrate or ethyleneimine (co)
The polymer long-chain alkyl isocyanate graft-modified layer is a saponified or partially saponified long-chain alkyl isocyanate-grafted modified copolymer of polyvinyl acetate or a copolymer of vinyl acetate and a copolymerizable monomer. Alternatively, it means a layer composed of polyethyleneimine or a long-chain alkyl isocyanate graft-modified copolymer of ethyleneimine and a copolymerizable copolymerizable monomer.

The thickness of the layer of the above-mentioned saponified vinyl acetate (co) polymer modified with alkyl isocyanate or the modified long-chain alkyl isocyanate with ethyleneimine (co) polymer is not particularly limited. However, it is preferably 0.01 to 10 μm, more preferably 0.03 to 0.5 μm. The thickness of the above layer is 0.01
If it is less than μm, the adhesive force of the silicone-based adhesive layer wound thereon may increase with time, and it may be difficult to rewind the adhesive tape from the adhesive tape roll with an appropriate developing force, On the other hand, if the thickness exceeds 10 μm, the peeling function is saturated, and the cost is merely increased.

Means for applying the alkyl isocyanate graft-modified saponified vinyl acetate (co) polymer or the long-chain alkyl isocyanate graft-modified ethyleneimine (co) polymer to a synthetic resin film substrate is as follows:
There is no particular limitation, and examples thereof include a reverse roll coater, a kiss coater, a nip coater, a gravure coater, a comma coater, a knife coater, a spray coater, and a cast coater.

The silicone-based anchoring agent is not particularly limited as long as it is used for a silicone-based pressure-sensitive adhesive tape, and any commercially available silicone-based anchoring agent may be used. The silicone-based anchoring agent is a base material on which a layer of a saponified vinyl acetate (co) polymer modified with alkyl isocyanate or a modified long-chain alkyl isocyanate of ethyleneimine (co) polymer is formed. It is coated on the opposite side, but after coating, it is once wound into a roll and cured. The coating thickness of the silicone-based anchor agent is appropriately set for each type of anchor agent used.

The silicone-based pressure-sensitive adhesive is not particularly limited as long as it is used for a silicone-based pressure-sensitive adhesive tape, and any commercially available one may be used. The silicone-based pressure-sensitive adhesive is applied on the cured silicone-based anchor agent layer.

The means for applying the silicone-based anchoring agent and silicone-based pressure-sensitive adhesive is not particularly limited.
The same method as the above-mentioned means for applying the alkyl isocyanate graft modified product of the saponified vinyl acetate (co) polymer or the long chain alkyl isocyanate graft modified product of the ethyleneimine (co) polymer may be used.

The method for producing a silicone-based pressure-sensitive adhesive tape according to the present invention comprises applying a silicone-based anchoring agent to a synthetic resin film substrate treated with a specific back surface treatment agent as described above, and temporarily winding the film in a roll. The coating process is divided into two steps, the silicone-based pressure-sensitive adhesive coating process in the later step, and curing during that time. Therefore, there is no restriction on the production equipment, and there is no restriction on the productivity of the anchoring agent coating. Productivity can be greatly improved. Moreover, even if the rolled material coated with the silicone-based anchor agent stays for a considerable period of time, the silicone-based anchor agent migrates to the back surface of the base material and blocks when the silicone-based pressure-sensitive adhesive coating process is restarted. When unwinding the roll, the peeling force is increased, making it difficult to pull out the raw material to the coating device, or the silicone-based adhesive agent is partially peeled off the silicone-based anchor agent-coated surface, resulting in a silicone-based adhesive. A silicone-based pressure-sensitive adhesive can be applied without fear of lowering the anchor of the agent.

The proof that the silicone-based pressure-sensitive adhesive is firmly anchored to the synthetic resin film substrate is that a wide-width silicone-based pressure-sensitive adhesive tape coated in this manner is further used to separate narrow-width silicone-based adhesive tapes. When slitting the pressure-sensitive adhesive tape, it can be seen from the fact that the above-mentioned pressure-sensitive adhesive layer does not peel off from the slit portion and that the number of the side sticks of the individual silicone pressure-sensitive adhesive tapes is small.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

Example 1 An octadecyl isocyanate graft-modified product of a partially saponified vinyl acetate copolymer (on the other hand, trade name "Piroyl 10
10)) so as to have a coating thickness of 1 μm, and 13
A silicone-based anchoring agent (trade name “X-40-3006A” manufactured by Shin-Etsu Chemical Co., Ltd.) having a thickness of 3 μm was applied to the opposite surface of the PET film substrate having a thickness of 50 μm dried at 0 ° C. for 3 minutes.
, And once wound up and cured at room temperature for 24 hours.

Next, the backed and anchored raw material wound up in a roll is pulled out, and a silicone-based adhesive (trade name "X-40-3068" manufactured by Shin-Etsu Chemical Co., Ltd.) is used.
Was applied to a thickness of 30 μm to prepare a silicone-based pressure-sensitive adhesive tape.

(Example 2) Same as Example 1 except that the drying conditions at the time of applying the partially octadecyl isocyanate graft modified product of the partially saponified vinyl acetate copolymer of Example 1 were changed to 130 ° C for 90 seconds. To prepare a silicone-based pressure-sensitive adhesive tape.

(Example 3) Same as Example 1 except that the drying conditions at the time of applying the partially octadecyl isocyanate graft modified product of the partially saponified vinyl acetate copolymer of Example 1 were changed to 130 ° C for 15 seconds. To prepare a silicone-based pressure-sensitive adhesive tape.

Example 4 An octadecyl isocyanate graft modified ethyleneimine copolymer (Ohara Palladium Co., Ltd., trade name: A silicone-based pressure-sensitive adhesive tape was produced in the same manner as in Example 1, except that NPU ") was used.

(Example 5) A silicone-based copolymer was prepared in the same manner as in Example 2 except that the drying conditions for coating the octadecyl isocyanate graft modified product of the ethyleneimine copolymer of Example 2 were changed to 130 ° C for 90 seconds. An adhesive tape was produced.

Example 6 Silicone was prepared in the same manner as in Example 2 except that the drying conditions for coating the octadecyl isocyanate graft modified product of the ethyleneimine copolymer of Example 2 were changed to 130 ° C. for 15 seconds. An adhesive tape was prepared.

Comparative Example 1 A silicone-based pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the partially octadecyl isocyanate-grafted modified product of the vinyl acetate copolymer of Example 1 was not used.

In order to evaluate the production methods of the silicone pressure-sensitive adhesive tapes of Examples 1 to 6 and Comparative Example 1, the blocking performance of the roll-shaped raw material before the application of the silicone pressure-sensitive adhesive was evaluated by the following test method. . The evaluation results are shown in Table 1.

(Evaluation method) Blocking test: After leaving the back-treated and anchor-treated raw material at 23 ° C. for 24 hours, when pulling out the raw material from the unroll stand of the silicone-based pressure-sensitive adhesive coating apparatus, ア ン カ ー: anchor No transfer was visually observed on the back surface of the PET film substrate, and the dispensing was smooth. X: The transfer of the anchor agent was visually confirmed, and the dispensing of the raw material was heavier than usual. It was evaluated in two stages.

[0028]

[Table 1]

(Example 7) Except that the coating thickness of the octadecyl isocyanate graft modified product of the partially saponified vinyl acetate copolymer of Example 1 was changed to 0.1 μm,
A silicone pressure-sensitive adhesive tape was produced in the same manner as in Example 1. The raw material subjected to the back surface treatment and the anchor treatment was substantially free from blocking, and could be extremely smoothly fed when the silicone pressure-sensitive adhesive was applied.
Comparative Example 2 A silicone pressure-sensitive adhesive tape was produced in the same manner as in Comparative Example 1, except that the coating thickness of the silicone pressure-sensitive adhesive of Comparative Example 1 was changed to 0.1 μm.

In order to evaluate the production methods of the silicone-based pressure-sensitive adhesive tapes of Examples 1, 7 and Comparative Example 2, the self-back surface adhesive force, spreading force, and curl performance of the roll-shaped raw material before the application of the silicone-based pressure-sensitive adhesive were evaluated. Was evaluated by the following test method.
Table 2 shows the evaluation results.

(Evaluation method) Self-back surface adhesive strength: According to JIS Z 0237, the self-back surface adhesive force is 2 degrees by a 90 degree peeling method.
After standing at 3 ° C. for 24 hours and at 70 ° C. for 24 hours,
It measured about the sample left at 23 degreeC for 20 minutes.

2. Developing force: The peeling (developing) force required when a 25-mm-wide sample wound on a 3-inch paper core is wound onto a paper core of the same diameter at a speed of 30 m / min is measured, and the result is measured by a self-recording recorder. Recorded.

3. Curl: Using a tape dispenser manufactured by Elm Industry Co., Ltd., trade name "M-1000", the state of operation due to the curl was evaluated in two stages: ：: good operation, X: malfunction did.

[0034]

[Table 2]

[0035]

The method for producing a silicone-based pressure-sensitive adhesive tape according to the present invention is constituted as described above, so that a synthetic resin film can be produced at a low cost without using a special back surface treating agent such as expensive silicon fluoride. It shows good adhesion to the substrate and a smooth coated surface, and shows excellent rewinding and peeling properties of the adhesive tape, and enhances the productivity of the anchor agent coating and the productivity of the silicone adhesive tape. It can be greatly improved. Moreover, even if the rolled material coated with the silicone-based anchor agent stays for a considerable period of time, the silicone-based anchor agent migrates to the back surface of the base material and blocks when the silicone-based pressure-sensitive adhesive coating process is restarted. When unwinding the roll, the peeling force is increased, making it difficult to pull out the raw material to the coating device, or the silicone-based adhesive agent is partially peeled off the silicone-based anchor agent-coated surface, resulting in a silicone-based adhesive. A silicone-based pressure-sensitive adhesive can be applied without fear of lowering the anchor of the agent.

Claims (1)

[Claims] 1. A synthetic resin film base on one surface of which a layer of a modified alkyl isocyanate graft of a saponified vinyl acetate (co) polymer or a modified long chain alkyl isocyanate of an ethyleneimine (co) polymer is formed. A silicone-based pressure-sensitive adhesive tape characterized by applying a silicone-based anchoring agent to the other surface of the material, winding it once into a roll, curing it, and then laminating a silicone-based pressure-sensitive adhesive layer on the anchoring agent-coated surface. Manufacturing method.