JP2717190B2 - Release agent and release film, adhesive member and separator - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a release film excellent in oil-based ink printability and release / adhesion balance, comprising a urethane resin and silicone, and a water-based release agent for forming such a film. And an adhesive member and a separator having such a film.

2. Description of the Related Art In order to facilitate peeling from an adhesive surface, a peelable film applied to an adhesive tape or a separator is required to have a proper peeling / adhesion balance with an adherend due to a winding process or the like. You.
In addition, it is also desirable that printing be possible because of the need for address writing and the like. Furthermore, from the viewpoint of environmental hygiene and safety against fire, it is desirable to be able to prepare as a water-based release agent and to avoid using an organic solvent.

Heretofore, a release film made of a cured silicone film has been known. However, there has been a problem that the peeling / adhesion balance with the adherend is inferior and the peeling performance is too high, for example, in the case of a pressure-sensitive adhesive tape, it is not possible to overlap and adhere. In addition, there is also a problem that printing cannot be performed because the oil-based ink is repelled.

On the other hand, in order to impart oil-based ink printability, a silicone-based release agent in which fine powdered silica or ethylcellulose is blended with a special polysiloxane has been proposed (JP-A-59-12647).
No. 5, JP-A-59-147048). However, there is a fatal problem that the release agent is not sufficiently cured, and the balance between release and adhesion to the adherend is not sufficient. There is also a problem that it is necessary to prepare a liquid using an organic solvent in order to ensure the viscosity and homogeneity of the release agent.

Means for Solving the Problems The present inventors have overcome the above problems, can be prepared as a water-based release agent, excellent in the balance of separation and adhesion with the adherend,
As a result of intensive studies to develop a peelable film having oil-based ink printability, they have found that a composite film of a urethane resin and silicone can achieve the object, and have accomplished the present invention.

That is, the present invention is characterized in that, in a medium composed of water, 100 parts by weight of a siloxane segment-free urethane resin that forms a composite film together with a separately blended silicone, and 0.1 to 500 parts by weight of the silicone. Release agent, and composed of a composite film of a urethane resin and silicone, a release film characterized by having oil-based ink printability, and the release film on one side of the support substrate,
An object of the present invention is to provide an adhesive member having an adhesive layer on the other surface, and a separator having the peelable film on one or both surfaces of a supporting substrate.

Action By forming a composite film consisting of a combination of urethane resin and silicone, the wettability of oil-based ink based on urethane resin and the releasability based on silicone are fused, and the releasability is excellent in oil-based ink printability and excellent balance between release and adhesion. A film is formed. Further, the use of such a component makes it possible to prepare a water-based release agent comprising an emulsion or an aqueous solution.

Examples of constituent elements of the invention The urethane resin used in the present invention does not contain a siloxane segment in molecules such as side chains, and has the ability to form a film, and forms a composite film with silicone which is separately compounded. Should be fine. Urethane resins having any structure that does not contain a siloxane segment in the molecule, such as an aromatic type, a non-yellowing type, a reactive type, a non-reactive type, a water-soluble type and a water-insoluble type, may be used. When a water-based release agent is prepared using a water-insoluble and non-self-emulsifying urethane resin, an emulsification is performed by forced emulsification using a surfactant in combination.

The silicone used in the present invention is a polyorganosiloxane. Generally, an oily polyorganosiloxane that is cured through a functional group is used. Thus, any of the known silicones in conventional release agents can be used. As a typical example, a polyorganosiloxane having an alkenyl group and a polyorganohydrogensiloxane are blended in a molar ratio based on SiH units / C = C units of 0.1 to 10 so as to be cured with a platinum-based catalyst. Addition-reaction type silicone, polyorganosiloxane having silanol group and polyorganohydrogensiloxane which are cured with a catalyst such as metal carboxylate, polyorganosiloxane having epoxy group, diazonium salt, sulfonium And cationic polymerization type silicone cured with an onium salt-based catalyst such as a salt or an iodonium salt.

The release agent of the present invention is prepared as a liquid using water as a medium, using one or more urethane resins and silicone. However, even if a release agent is prepared as a solution using an organic solvent, a release film composed of a target composite film can be formed.

The aqueous medium-based release agent can be prepared by an appropriate method such as, for example, a method of mixing urethane resin or silicone as an emulsion or an aqueous solution and mixing them, or a method of adding each component to an aqueous medium and stirring them to form an emulsion. You can go in. The silicone emulsion can be obtained by stirring the silicone with water using a stirrer such as a homogenizer while using an appropriate surfactant and an emulsion stabilizer.

In the case of mixing a urethane resin emulsion and a silicone emulsion, if the combination of surfactants used for emulsification is a cationic type or an anionic type, emulsion particles may be broken and a stable mixture may not be formed. In addition,
When a silicone curing catalyst is separately mixed, a method in which the silicone and the curing catalyst are mixed and then mixed with a urethane resin emulsion is preferable from the viewpoint of the curability of the release agent obtained.

The appropriate amount of silicone used is 0.1 to 500 parts by weight per 100 parts by weight of the urethane resin. If the amount used is less than 0.1 part by weight, the peeling performance is poor, and if it exceeds 500 parts by weight, the printability of the oil-based ink is poor and a composite film having an excessive peeling performance in the peeling / adhesion balance is obtained.

The release agent of the present invention, in the case of an emulsion system, the mixed solution is diluted with water as needed, and the content of non-volatile components is 0.1%.
It is appropriate to prepare it to be about 80% by weight. If the content is less than 0.1% by weight, the stability of the emulsified state in the release agent becomes poor. On the other hand, if it exceeds 80% by weight, it becomes difficult to form a thin film of the peelable film, and the composition tends to vary. In addition, an appropriate additive such as a filler may be added to the release agent as needed.

The formation of the peelable film may be performed by a known method. Therefore, the release agent is applied to the object to be processed by an appropriate application means using, for example, a roll coater, a kiss coater, a slot die coater, a squeeze coater, or the like. The coating amount is generally 0.01 to 10 g / m ² . Next, the coating layer can be formed by drying and curing. When curing by heat treatment, drying and curing can be performed in one step. The heat treatment temperature is generally from 60 to 200 ° C. When a plurality of curing methods such as a heat treatment and an ultraviolet irradiation treatment can be used, the curing method may be appropriately determined.

The silicone-based release agent of the present invention is preferably used in applications where it is desired to be adhered to an adhesive surface and to be easily peeled off from the adhesive surface, such as formation of a separator or back surface treatment of an adhesive member such as an adhesive tape.

The pressure-sensitive adhesive member of the present invention has the above-mentioned releasable film provided on one surface of a support substrate and a pressure-sensitive adhesive layer provided on the other surface. Also,
The separator has such a peelable film provided on one or both sides of a supporting substrate. There is no particular limitation on the supporting substrate used. Generally, paper, plastic laminated paper, cloth, plastic laminated cloth, plastic film, metal foil, foam, and the like are used. The formation of the pressure-sensitive adhesive member may be performed by a known method such as a method of applying a pressure-sensitive adhesive to the other surface of the support substrate on which the peelable film is provided in advance.

Effects of the Invention Since the peelable film of the present invention is composed of a composite film of a urethane resin and silicone, it has an excellent balance of peeling and adhesion to an adherend and is excellent in oil-based ink printability. In addition, the release agent can be prepared as an aqueous medium, and the coating layer is excellent in curability and hardly falls off from the object.

As a result, according to the pressure-sensitive adhesive member and the separator of the present invention having such a peelable film, the adhesive surface is less likely to be contaminated by the peelable film, and the adhesion is favorably maintained.

EXAMPLES Example 1 75 parts (parts by weight, hereinafter the same) of a silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM-768, solid content: 30% by weight) and 2.5 parts of a curing catalyst (PM-6, manufactured by Shin-Etsu Chemical Co., Ltd.) are homogenized. And 100 parts of a non-yellowing urethane resin emulsion (HUX-290H, solid content 65% by weight, siloxane segment-free material) and 1375 parts of distilled water are added to the mixture. And sufficiently mixed to prepare a stable release agent of the present invention.

Next, the above-mentioned release agent was applied to a wire bar coater (Rod No.
In 3), a coating amount of 7 g / m ² (liquid base) is applied to the laminated surface of polyethylene laminated kraft paper having a thickness of 120 μm, and this is applied in a hot air circulation type dryer (10
(0 ° C.) for 5 minutes to obtain a separator.

Example 2 150 parts of silicone emulsion (same as above), 4.5 parts of curing catalyst (same as above), non-yellowing type urethane resin colloid solution (manufactured by Asahi Denka, HUX-232, solid content 30% by weight, siloxane segment-free) A stable release agent of the present invention was prepared in the same manner as in Example 1 using 100 parts) and 1250 parts of distilled water to obtain a separator.

Example 3 30 parts of a silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM-765, solid content: 23% by weight), a curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-4)
F) 2 parts, 100 parts of non-yellowing urethane resin emulsion (HUX-290H, solid content 65% by weight, manufactured by Asahi Denka Co., Ltd.) and distilled water 590
Using the parts, a stable release agent of the present invention was prepared according to Example 1 to obtain a separator.

Example 4 30 parts of silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM-768, solid content: 30% by weight), curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-6)
Using 1 part, 100 parts of a non-yellowing type urethane resin emulsion (manufactured by Asahi Denka Co., HUX-290H, solid content 65% by weight) and 610 parts of distilled water, a stable release agent of the present invention was prepared according to Example 1. Thus, a separator was obtained.

Comparative Example 1 100 parts of a silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM-768, solid content: 30% by weight), a curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-
6) A release agent was prepared according to Example 1 using 3 parts and 200 parts of distilled water to obtain a separator. Therefore, the release film does not contain a urethane resin component.

Comparative Example 2 Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM-768, solid content 30% by weight) 175 parts, curing catalyst (Shin-Etsu Chemical Co., Ltd., PM-
6) 5 parts, polyester emulsion (Toyobo Co., Ltd.,
A release agent was prepared in the same manner as in Example 1 using 100 parts of Vironal MD-1200 (solid content: 35% by weight) and 1475 parts of distilled water to obtain a separator. Therefore, the peelable film contains a polyester component instead of the urethane resin component.

Evaluation Test The following characteristics were examined for the separators obtained in the examples and comparative examples.

[Curability] When the peelable film of the separator did not have stickiness, it was evaluated as ○, when there was some stickiness, as Δ, and when the stickiness was large, as X.

[Printability] With a commercially available oil-based ink pen, letters were written on the surface of the peelable film on the separator, and 場合 was evaluated when no repelling was observed, ○ when almost no repelling was observed, Δ was slightly observed, and X was marked when extremely remarkable.

[Peeling force] A commercially available adhesive tape of 25 mm width (Kraft tape No. 712, manufactured by Nitto Denko Corporation) is reciprocated on a 2 kg rubber roller once at 20 ° C and 65% RH on the peelable film surface of the separator. After pressure bonding, the adhesive tape is left under a load of 50 g / cm ² at 20 ° C. for 48 hours. Thereafter, the load was released, and the tape was left at 20 ° C and 65% RH for 2 hours. The adhesive tape was peeled off at a speed of 300 mm / min with a shopper (180 ° peel), and the force required for the peeling was determined. (Average value of 4 samples).

[Residual adhesive rate] (Non-staining property of the adhesive surface)
H. Under the stainless steel plate (SUS27CP) water-resistant abrasive paper (No. 280)
After the rubber roller having a weight of 2 kg was reciprocated once and pressed against the cleaned surface, the force required for peeling was determined in the same manner as above for the one left for 30 minutes. Then, the ratio of the residual adhesive force of the obtained measured value to the measured value of the pressure-sensitive adhesive tape which was not brought into contact with the peelable film surface in the same manner as described above was calculated as the residual adhesive ratio (average of four samples). value).

 The results are shown in the table.

As is clear from the table, the release agent of the present invention is excellent in curability, and the release film is excellent in oil-based ink printability and excellent balance between release and adhesion to an adherend such as an adhesive surface.

Claims (4)

(57) [Claims] In a medium comprising water, 100 parts by weight of a siloxane segment-free urethane resin which forms a composite film together with a separately formulated silicone;
A release agent comprising 0 parts by weight. 2. A releasable film comprising a composite film of a urethane resin and silicone and having oil-based ink printability. 3. A pressure-sensitive adhesive member having a release film according to claim 2 on one side of a support substrate and a pressure-sensitive adhesive layer on the other side. 4. A separator comprising the releasable film according to claim 2 on one or both sides of a support substrate.