JPH02208384A - Release agent and releasing film, and self-adhesive member and separator - Google Patents

Abstract

PURPOSE:To enable the preparation of a releasing film which has an excellent printability with an oil-base ink and a good balance between release and adhesion by making a composite film comprising a combination of a urethane resin with silicone. CONSTITUTION:A release agent is prepd. by compounding 100 pts.wt. film- forming urethane resin, 0.1-500 pts.wt. silicone, and an aq. medium. One side of a substrate is coated with said release agent and the other side with a self adhesive to give a self-adhesion member; one side or both sides are coated with said release agent to give a separator.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a release film containing urethane resin and silicone that has excellent oil-based ink printability and a good balance between release and adhesion, and an aqueous release agent for forming such a film. , and an adhesive member and a separator having such a film.

Conventional technology and issues Release films applied to adhesive tapes, separators, etc. to facilitate peeling from the adhesive surface require an appropriate balance of peeling and adhesion with the adherend due to winding, etc. Ru. It is also desirable that it be printable for purposes such as writing addresses.

Furthermore, from the viewpoint of environmental hygiene and fire safety, it is desirable that the stripping agent can be prepared as an aqueous stripping agent, thereby avoiding the use of organic solvents.

Conventionally, peelable films made of cured silicone films have been known. However, there are problems in that the balance between peeling and adhesion to adherends is poor, and the peeling performance is too good, making it impossible to overlay adhesive tapes, for example. There was also the problem that printing was not possible because the oil-based ink was used as a bullet.

On the other hand, in order to provide oil-based ink printability, a silicone-based release agent has been proposed, which is a mixture of special polysiloxane with fine powder and ethyl cellulose (JP-A-59-1
No. 26475, No. 59-147048). However, this has the fatal problem that the release agent does not harden sufficiently, and the balance between release and adhesion to the adherend is also insufficient.

Another problem is that in order to ensure the viscosity and homogeneity of the stripping agent, it is necessary to prepare it as a liquid using an organic solvent.

Means for Solving the Problems The present inventors have overcome the above problems and have developed a release film that can be prepared as an aqueous release agent, has an excellent balance of release and adhesion with adherends, and has oil-based ink printability. As a result of extensive research in order to develop this, it was discovered that the objective could be achieved with a composite film of ureta 1-silicone, and the present invention was completed.

That is, the present invention provides a release agent characterized by containing a urethane resin having film-forming ability and 0.1 to 500 parts by weight of silicone per 100 parts by weight of this resin in a medium consisting of water, and a urethane resin. A releasable film comprising a composite film of resin and silicone and having oil-based ink printability, and a supporting base material having the releasable film on one side and an adhesive layer on the other side. The present invention provides a separator characterized by having the above-mentioned peelable film on one or both sides of a support base material.

By creating a composite film consisting of a combination of urethane resin and silicone, the wettability of oil-based inks based on urethane resin and the releasability (based on silicone) are combined, resulting in excellent oil-based ink printing performance and an excellent balance of release and adhesion. A peelable film is formed.Furthermore, by using such components, it is possible to prepare an aqueous release agent consisting of an emulsion or an aqueous solution.

Examples of Constituent Elements of the Invention The urethane resin used in the present invention may be any urethane resin as long as it has film-forming ability. Urethane resins of any structure, such as aromatic type, non-yellowing type, reactive type, non-reactive type, water-soluble type, or non-water-soluble type, may be used. When preparing an aqueous release agent using a urethane resin that is non-aqueous and non-self-emulsifying, it is used by making an emulsion by forced emulsification using a surfactant or the like.

The silicone used in the present invention is a polyorganosiloxane. Generally, oily polyorganosiloxanes that are cured through functional groups are used.

Accordingly, any of the known silicones in conventional release agents may be used. As a typical example, a polyorganosiloxane having an alkenyl group and a polyorganosiloxane are blended so that the molar ratio based on SiH units/C=C units is 0.1 to 10, Addition reaction silicone cured with a platinum-based catalyst, condensation reaction silicone cured with a catalyst such as metal) J rubonate of polyorganosiloxane and polyorganohydrodiene siloxane having silanol groups, and epoxy group Examples include cationically polymerized silicones in which polyorganosiloxanes having the following are cured with onium salt catalysts such as diazonium salts, sulfonium salts, and iodonium salts.

The release agent of the present invention is prepared as a liquid using water as a medium using one or more types of urethane resin and silicone. However, even if the release agent is prepared as a solution using an organic solvent, it is possible to form the desired release film consisting of a composite film.

A water-based release agent can be prepared by any appropriate method, such as making an emulsion or aqueous solution of urethane resin or silicone and mixing it, or adding each component to an aqueous medium and stirring it to form an emulsion. You can go there. A silicone emulsion can be obtained by stirring silicone with water using a stirrer such as a homogenizer in combination with an appropriate surfactant and emulsion stabilizer.

When mixing a urethane resin emulsion and a silicone emulsion, if the combination of surfactants used for emulsification is a cationic type and an anionic type, the emulsion particles may be destroyed and a stable mixture may not be formed. In addition, when the curing catalyst for silicone is mixed separately, it is preferable to mix the silicone and the curing catalyst and then mix it with the urethane resin emulsion in terms of the curability of the resulting release agent.

The appropriate amount of silicone to be used is 0.1 to 500 parts by weight per 00 parts by weight of the urethane resin. If the amount used is less than 0.1 parts by weight, the peeling performance will be poor, and if it exceeds 500 parts by weight, the oil-based ink printability will be poor, resulting in a composite film with excessive peeling performance in terms of the balance of peeling and adhesion.

When the stripping agent of the present invention is an emulsion type, the above-mentioned mixed solution is diluted with water as necessary to reduce the non-volatile content to 0.1.
It is appropriate to adjust the amount to 80% by weight. If the content is less than 0.1% by weight, the stability of the emulsified state in the release agent will be poor.

On the other hand, if it exceeds 80% by weight, it becomes difficult to form a thin peelable film and its composition tends to vary.

Note that appropriate additives such as fillers may be added to the release agent as necessary.

Formation of the peelable film may be performed by a known method.

Therefore, the release agent is coated on the object to be treated using an appropriate coating method using, for example, a roll coater, kiss coater, slot die coater, squeeze coater, or the like. Coating amount is 0.01-10
g/n? is common. The coating layer can then be dried and cured to form the coating layer. When curing by heat treatment, drying and curing can be performed in one step. The heat treatment temperature is generally 60 to 200°C. In addition, when a plurality of curing methods such as heat treatment and ultraviolet irradiation treatment can be used, the curing method may be determined as appropriate.

The silicone release agent of the present invention can be used, for example, in the formation of separators and in the back treatment of adhesive members such as adhesive tapes.
It 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.

The adhesive member of the present invention has the above-mentioned releasable film provided on one side of a supporting base material and an adhesive layer provided on the other side. Furthermore, the separator is one in which such a releasable film is provided on one or both sides of a supporting base material. There are no particular limitations on the supporting base material to be used. Generally, paper, plastic laminated paper,
Cloth, plus deck laminate cloth, plastic film, metal foil/foam, etc. are used. Note that the adhesive member may be formed by a known method such as a method of applying an adhesive to the other surface of a supporting base material on which a releasable film has been previously provided.

Effects of the Invention Since the releasable film of the present invention is composed of a composite film of urethane resin and silicone, it has an excellent balance of release and adhesion to adherends, and has excellent oil-based ink printability. In addition, the release agent can be prepared as an aqueous medium, and the coating layer has excellent curability and is less likely to fall off from the object to be treated.

As a result, according to the adhesive member and separator of the present invention having such a releasable film, the adhesive surface is less likely to be contaminated by the releasable film, and adhesive strength is maintained well.

Examples Example 1 Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM768,
After thoroughly stirring and mixing 75 parts (solid content 30% by weight) (parts by weight, same hereinafter) and 2.5 parts of a curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-6) with a homogenizer, a non-yellowing urethane resin was added to the mixture. Emulsion (manufactured by Asahi Denka Co., Ltd., I-I U X-2
90H) Solids content 65% by weight) lo.

1,375 parts of distilled water were added and thoroughly stirred and mixed using a homogenizer to prepare a stable stripping agent of the present invention.

Next, the above release agent was coated with a wire bar coater (RodNo.
, 3), the coating amount was 7 g/1I on the laminated surface of polyethylene laminated kraft paper with a thickness of 120 parts m.
i (liquid base), and dried and cured in a hot air circulation dryer (100°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 urethane resin colloidal solution (manufactured by Asahi Denka Co., Ltd., HUX-232, solid content 30
A stable stripping agent of the present invention was prepared according to Example 1 using 100 parts (% by weight) and 1250 parts of distilled water, and a separator was obtained.

Example 3 Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KM-765
, solid content 23% by weight) 30 parts, curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-4F) 2 parts, non-yellowing type urethane resin emulsion (manufactured by Mudenka Co., Ltd., HUX-290H, solid content 65% by weight)
) and 590 parts of distilled water to prepare a stable stripping agent of the present invention according to Example 1, and obtain a separator.

Example 4 Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., K M-76
8. Solid content 30% by weight) 30 parts, curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-6) 1 part, non-yellowing type urethane resin emulsion (manufactured by Mudenka Co., Ltd., HU X-290H1 solid content 65% by weight) 100 parts A stable stripping agent of the present invention was prepared according to Example 1 using 610 parts of distilled water, and a separator was obtained.

Comparative Example 1 Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., KMT68,
Example 1 using 100 parts of solid content (solid content: 30% by weight), 3 parts of curing catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., PM-6), and 200 parts of distilled water.
A separator was obtained by preparing a release agent according to . Therefore, the peelable 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 (manufactured by Shin-Etsu Chemical Co., Ltd., PM-6) 5 parts, polyester emulsion (manufactured by Toyobo Co., Ltd., Pyronal MD-1200, solid content 35% by weight) 100 parts, and distilled water 1475 parts Example 1 using part
A separator was obtained by preparing a release agent according to . Therefore, the peelable film contains a polyester component instead of the urethane resin component.

The following properties of the separators obtained in the evaluation test examples and comparative examples were investigated.

[Curability] The peelable film of the separator was evaluated as ◯ if there was no stickiness, △ if there was some stickiness, and × if there was a lot of stickiness.

[Printability] Letters were written on the surface of the releasable film on the separator using a commercially available oil-based ink pen, and evaluation was made as ◎ if there was no repelling at all, ○ if there was almost no repelling, △ if there was some, and × if there was significant repelling.

[Peeling force] 20°C, 65%R,)1. At the bottom, a commercially available adhesive tape (manufactured by Nitto Denko Corporation, Craft Tape R1H712) with a width of 25+ nm was pressed onto the releasable film surface of the separator by moving a rubber roller weighing 2 kg back and forth once, and then a 50 g /cn? It was left at 20°C for 48 hours under a load of . After that, the load was released and the temperature was increased to 20°C.
The adhesive tape was left under 5% R, H for 2 hours, and the adhesive tape was peeled off using a Schopper at a speed of 300 + nm/min (180 degrees beer), and the force required for peeling was determined (for 4 samples). Average value).

[Residual adhesion rate] (Non-staining property of adhesive surface) After measuring the above peeling force, the adhesive tape was placed at 20°C, 65% R, H, under stainless steel plate (SOS27CP) and waterproof abrasive paper (2
80), and then apply a 2k weight coat to the cleaned surface.
The force required for peeling was determined in the same manner as above for the sample which was pressed by moving the rubber roller (g) back and forth once and then left for 30 minutes. Then, the ratio of the residual adhesive force of the obtained measured value to the measured value obtained for the adhesive tape that had never been brought into contact with the releasable film surface in the same manner as above was calculated as the residual adhesive rate (average of 4 samples). value).

The results are shown in the table.

As is clear from the table, the release agent of the present invention has excellent curability, and its release film has excellent oil-based ink printability and a balance of release and adhesion to adherends such as adhesive surfaces.

Patent applicant: Nitto Denko Corporation

Claims (1)

[Scope of Claims] 1. A release agent characterized by containing a urethane resin having film-forming ability and 0.1 to 500 parts by weight of silicone per 100 parts by weight of this resin in a medium consisting of water. 2. A peelable film consisting of a composite film of urethane resin and silicone, which is characterized by having oil-based ink printability. 3. An adhesive member comprising the releasable film according to claim 2 on one side of a supporting base material and an adhesive layer on the other side. 4. A separator comprising the releasable film according to claim 2 on one or both sides of a supporting base material.