JP2001288399A - Coating agent for imparting releasability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous coating agent for imparting releasability which can form a coating film having light transmissivity and not spoiling the appearance of the surface of a structure coated with the dry coating film, and also can easily and effectively modify the surface in such a way as to have releasability. SOLUTION: This coating agent for imparting releasability comprises a film-forming polymer and an aqueous medium, and is used for forming the coating-film imparting releasability and having light transmissivity on the surface of a structure. The film-forming polymer is set to contain an acrylic silicone and to have the silicon content of 5-65 mass %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD [0001] The present invention relates to a structure,
More particularly, the present invention relates to a release coating agent for imparting releasability to a paper adhesive (adhesive, etc.). The present invention relates to a releasable coating agent for preventing paper sticking, which does not impair the aesthetic appearance of the surface and has a small environmental load.

[0002]

2. Description of the Related Art In recent years, a situation has frequently occurred where a sticker is stuck on the surface of an outdoor structure such as a building outer wall, a telephone pole, a telephone box or the like without permission. Such a sticking paper is a problem in that a part of the adhesive such as a sticking paper or an adhesive remains on the surface of the structure when peeled off, and this is a problem in that the appearance of the structure surface is impaired, and various methods for preventing the sticking paper are used. Is disclosed.

For example, there has been disclosed a method in which an embossed steel plate, a film having irregularities, or the like is pasted on the surface of a structure in advance to impart releasability to a pressure-sensitive adhesive of a pasting paper (Japanese Patent Laid-Open No. 55-55). No. 129,477, Japanese Patent Application Laid-Open No. Sho 60-255418, Japanese Utility Model Laid-Open No. 57-98474.
JP, JP-A-62-163267, JP-A-5-163267
No. 21059). However, in these methods, since the surface of the structure is covered with a low-transparency steel plate or film, there is a problem that the aesthetic appearance (color, pattern, design, etc.) of the structure surface is impaired.

[0004] Further, there is disclosed a method in which a film-forming polymer such as a silicone-based polymer is applied to the surface of a structure in advance to form a coating film, and the releasability of the adhesive paper from the adhesive is imparted. For example, Japanese Patent Application Laid-Open No. 11-269430 discloses an anti-sticking coating agent comprising a silicone-based polymer. This anti-paste coating agent is a one-pack type that does not require a curing process and is useful in that it does not require heat curing.However, since it is an organic solvent-type paint, odor due to the solvent during construction may cause a problem. Also, it is not preferable in that the load on the environment is large.

Here, acrylic silicones widely used in the fields of release agents, water repellents, lubrication, etc. are disclosed in
No. 94911), a material having both the adhesion (adhesion) of the acrylic to the substrate and the releasability of the pressure-sensitive adhesive of the silicone, and it is known that it can be prepared as an aqueous dispersion. Therefore, if acrylic silicone is used as a film-forming polymer, a coating-prevention coating agent that has both the adhesiveness of the coating film of the coating agent to the surface of the structure and the release property of the adhesive for the bonding paper and that does not use an organic solvent is constituted. Can be expected. Actually, a method for preventing sticking using acrylic silicone as a paint has already been proposed (JP-A-2-189).
372).

[0006]

However, since the coating disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2-189372 contains particles for forming irregularities such as aggregates, the coating having many irregularities on the surface of the coating. Are formed, and the aesthetic appearance of the structure surface is impaired. For example, the observer perceives that there is an originally unnecessary peelable coating film on the surface of the structure, and gives the observer a sense of incongruity (eg, the peelable coating film becomes unnecessarily conspicuous).

[0007] In addition, since the irregularity-forming particles are usually opaque, the coating film is not light-transmitting and draws characters, figures, and the like on the surface of the structure, and the design surface with the design property becomes invisible. Furthermore, it cannot be colored or decorated like a normal colored paint such as paint to impart design properties. Therefore,
A coating agent that gives a coating film containing the unevenness-forming particles could not modify the surface of the structure to a peeling property without impairing the appearance of the structure. In addition, it could not be used to color or decorate the structure so as to give it a design property, and at the same time, to modify the surface of the structure to be peelable.

[0008] On the other hand, conventional acrylic silicones have been used as a mixture with other film-forming polymers because a coating film formed using a single substance lacked flexibility and had insufficient adhesion to a structure. Have been. The coating material disclosed in JP-A-2-189372 also contains a non-silicone film-forming polymer such as acrylic urethane as a main component (the content of other film-forming polymer is larger than the content of acrylic silicone). It means that the mass is relatively larger.) Therefore, the releasability of the entire film-forming polymer tends to decrease, and it has been difficult to modify the surface of the structure to the releasability.

Further, as a result of the study by the present inventors, when a coating film substantially made of a conventional acrylic silicone is formed in a relatively low temperature environment (for example, outdoors in winter in Japan, etc.), the coating film is formed on the coating film. Cracks easily occur, as they are (for example, without using an additive such as a film forming aid or improving physical properties such as a minimum film forming temperature of acrylic silicone).
It has been found that when used, a problem arises as a coating agent for modifying the surface of the structure to have releasability.

[0010] Accordingly, a first object of the present invention is to form a light-transmitting coating film that does not impair the aesthetic appearance of the structure surface coated with the dried coating film, and that the surface can be easily and effectively peeled off. An object of the present invention is to provide an aqueous release coating agent which can be modified into a water-based release coating agent. A second object of the present invention is to provide a surface of a structure coated with a dry coating, which can be colored or decorated without impairing the aesthetic appearance, and at the same time, the surface can be easily and effectively modified to a peeling property. An object of the present invention is to provide a coating agent that can be used as a peelable colored paint.

[0011]

Means for Solving the Problems According to one aspect of the present invention, in order to achieve the first object, a film-forming polymer and an aqueous medium are contained, and the surface of a structure is peelable and light-transmissive. In the peelable coating agent for forming a coating film of the above, the film-forming polymer contains acrylic silicone, and the Si content of the film-forming polymer is 5-6.
5% by mass is provided.

In another aspect, the present invention provides:
In order to achieve the second object, a film-forming polymer,
An aqueous medium, containing a pigment, a peelable coating agent that can be used as a coloring paint for forming a peelable colored coating film on the surface of the structure, wherein the film-forming polymer contains acrylic silicone, and Wherein the Si content of the film-forming polymer is 5 to 65% by mass;
A releasable coating agent is provided.

In the coating agent of the present invention, since the film-forming polymer contains acrylic silicone and the Si (silicon) content is within the above range, the surface can be easily formed without using irregularity-forming particles such as aggregate. In addition, it can be effectively modified into a peeling property, and the coating film can be made light transmissive.

When the coating agent of the present invention contains a pigment, it can be used as a peelable colored paint. That is,
Since the coating film of the film-forming polymer is light-transmitting, it can be colored to a desired color by adding a pigment. Also in such a case, since the film-forming polymer contains acrylic silicone and the Si content is within the above range, a colored coating film can be formed, and the surface can be effectively modified to be peelable.

The coating agent of the present invention is preferably an aqueous dispersion containing a film-forming polymer, and more preferably an acrylic dispersion having an acrylic chain having a glass transition temperature of 60 ° C. or lower. The content of the acrylic silicone is determined so that the Si content of the film-forming polymer is 5 to 65% by mass.

Further, when the coating agent of the present invention is used as a vehicle for dispersing a pigment, and a colored coating is formed and used as a releasable coating agent, an aqueous dispersion containing a film-forming polymer and a pigment may also be used. Certain ones are preferable, and those containing acrylic silicone having a glass transition temperature of an acrylic chain of 60 ° C. or less are suitable. The content of the acrylic silicone is such that the Si content of the film-forming polymer is 5 to 5.
It is determined to be 65% by mass.

Further, the peelable coating agent of the present invention preferably has a minimum film-forming temperature of 5 ° C. or lower, and preferably has a viscosity of 500 to 8000 mPa · sec. It is preferable to include them.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A peelable coating agent according to a preferred embodiment of the present invention is characterized in that acrylic silicone having an Si content within a predetermined range is contained as a film-forming polymer. The releasable coating agent of the present invention is excellent in adhesiveness to the surface of a structure, releasability to a pressure-sensitive adhesive for pasting paper, and coatability, does not impair the aesthetic appearance of the surface of the structure, and has a low environmental load. . Hereinafter, the peelable coating agent as the anti-sticking coating agent of the present invention will be described.

(1) Film-forming polymer In the present specification, the term “film-forming polymer” refers to a polymer capable of forming a coating film (that is, film forming) when applied to the surface of a structure and dried. In other words, in the present invention, acrylic silicone is an essential component.

“Acrylic silicone” as used herein
Is a so-called silicone-modified acrylic polymer, which means a comb-shaped polymer having an acrylic polymer as a main chain and having a plurality of silicone side chains. Acrylic silicone is a material that has both the adhesion (adhesion) of the acrylic to the substrate and the releasability of the pressure-sensitive adhesive of the silicone. Combined, peelable coating agent (hereinafter referred to as "coating agent")
Can be configured.

The acrylic silicone can be produced by copolymerizing (graft copolymerizing) a polysiloxane macromer having a polymerizable functional group such as a vinyl group at at least one end with an acrylic monomer or acrylic oligomer. .

With respect to the releasability of the pressure-sensitive adhesive, the peel strength at room temperature under a tensile speed of 300 mm / min and a 180 ° peel test is preferably less than 1500 g / 25 mm, more preferably less than 1200 g / 25 mm, Particularly preferred is less than 1000 g / 25 mm. In order to obtain such peel strength, the Si content of the acrylic silicone may be controlled.

The acrylic silicone used in the present invention usually has a Si content of 5 to 65% by mass, as measured by H-NMR. If the Si content is too low, the releasability of the adhesive sheet from the adhesive may decrease, while if it is too high, the adhesiveness to the surface of the structure may decrease.

In the present invention, it is preferable to determine the Si content of the film-forming polymer in order to secure the above effects. For example, in a peelable coating agent that forms a light-transmitting coating film, the content of acrylic silicone contained in the film-forming polymer relative to the entire film-forming polymer is usually 50% by mass or more, preferably 60% by mass or more. And particularly preferably 70% by mass or more. In this case, it is better that the Si content of the acrylic silicone is relatively large,
60% by mass.

On the other hand, when the Si content of the acrylic silicone is relatively small, the content of the acrylic silicone contained in the film-forming polymer relative to the entire film-forming polymer is usually 90% by mass or more, preferably 95% by mass. As described above, the content is particularly preferably about 100% by mass. In this case, the Si content of the acrylic silicone may be usually in the range of 5 to 65% by mass, and preferably 10 to 60% by mass.

Further, the content of the acrylic silicone is preferably at least 40% by mass based on the total mass of the dried coating film obtained by applying and drying the coating agent,
More preferably 50% by mass or more, and 70% by mass.
It is particularly preferable that the above is satisfied. If the content of the acrylic silicone in the dried coating film is too low, the releasability of the pressure-sensitive adhesive decreases, while if it is too high, the adhesive force on the surface of the structure decreases, and the coating film is peeled off when the paper is peeled off. This is because the coating film may be damaged.

Further, the acrylic silicone in the present invention preferably has a glass transition temperature (hereinafter, referred to as “main chain Tg”) of an acryl chain as a main chain of 60 ° C. or lower. When the main chain Tg exceeds 60 ° C., the formed coating film lacks flexibility, and the adhesion to the structure becomes insufficient.

On the other hand, when the main chain Tg is too low, it is not preferable in that tack is generated on the surface of the coating film or the abrasion resistance of the coating film is reduced. Therefore, the main chain Tg is -3
The temperature is preferably from 0 to 60C, more preferably from -20 to 50C, and particularly preferably from -10 to 40C.

The main chain Tg is determined by appropriately selecting the type of a single acrylic monomer as a starting material of the main chain.
Alternatively, it can be controlled by appropriately selecting a plurality of acrylic monomers and adjusting the mixing ratio.
An acrylic silicone having a desired main chain Tg can be obtained by copolymerizing (grafting) these acrylic monomers (which may be oligomers) with a polysiloxane macromer.

(2) Medium The coating agent of the present invention is obtained by dissolving or dispersing a film-forming polymer in some medium, and is particularly preferably an aqueous dispersion containing a film-forming polymer.
This is because it is preferable not to use an organic solvent because there is no problem of odor at the time of construction and the load on the environment is small.

As a medium for dissolving or dispersing the film-forming polymer mainly composed of acrylic silicone, in addition to water, an alkylene glycol monoalkyl ether ester (for example, 3-methyl-3-methoxybutyl acetate, etc.) ) Can also be used in combination. Acrylic silicones can be prepared as aqueous dispersions and are also commercially available in dispersion form. From such a viewpoint, it is preferable that the medium is water.

(3) Additives Various additives other than the film-forming polymer can be added to the coating agent of the present invention as long as the effects of the present invention are not impaired.

Film Forming Aid The coating agent of the present invention preferably contains a film forming aid. This is for improving the film forming property of the acrylic silicone.

[0034] The content of the film-forming aid is determined based on the total weight of the dried coating film obtained by applying and drying the coating agent.
It is preferably 0.1 to 40% by mass, more preferably 1 to 30% by mass, and particularly preferably 5 to 25% by mass. If the content of the film-forming aid is too small, the film-forming properties are reduced, while if it is too large, the strength of the film is reduced. Is likely to peel off.

The film-forming auxiliary is a liquid at room temperature (about 25 ° C.), is highly compatible with acrylic silicone, has a high boiling point (normally 150 ° C. or higher), and has a relatively low evaporation rate. is there. For example, alcohols such as hexanol and polyethylene glycol and derivatives thereof can be suitably used.

Thickener The coating agent of the present invention preferably contains a thickener. This is for increasing the viscosity of the coating agent to a viscosity suitable for application.

The viscosity of the coating agent is preferably from 500 to 8000 mPa · s, more preferably from 700 to 5000 mPa · s, and even more preferably from 800 to 3000 mPa · s, as measured by a B-type viscometer. preferable. If the viscosity is too low, dripping tends to occur when applied to a vertical surface of an outdoor structure, and it becomes difficult to form a coating film, while if it is too high, the coating operation itself becomes difficult.

[0038] The content of the thickener for controlling the viscosity of the coating agent within the above range is usually 0.1 to 10% by mass, preferably 0.2 to 7% by mass based on the total mass of the dried coating film. %, Particularly preferably 0.3 to 5% by mass.

As the thickener, for example, guar gum such as propylene oxide-modified guar gum, or a water-soluble polymer such as ammonia-modified polyacrylic acid can be suitably used. Polyacrylic acid is generally a compound formed by polymerizing a starting monomer mixture containing acrylic acid and an acrylate ester, which may be modified with ammonia to form a water-soluble polymer suitable as a thickener. it can.

Other Additives The coating agent of the present invention may contain additives other than the film-forming aid and the thickener according to the purpose. For example, a crosslinking agent,
A curing agent, a curing component such as a curing accelerator, an antifoaming agent, a leveling agent, an ultraviolet absorber, an antioxidant, and the like may be added.
A tackifier such as a silicate resin may be added as an agent for improving the strength of the coating film.

In addition, a pigment can be dispersed in a coating agent to form a peelable colored paint. Such a colored paint can be usually formed using a coating agent containing a film-forming polymer and an aqueous medium as a vehicle, and using a usual dispersing device or stirring device. Further, it can also be formed by mixing a coating agent containing acrylic silicone and an aqueous medium and containing no pigment, and an aqueous coloring paint containing no acrylic silicone. The aqueous coloring paint containing no acrylic silicone preferably contains an acrylic polymer as a film-forming polymer. Since the pigment used in the peelable coloring paint has a smaller particle size than the concavo-convex forming particles of conventional aggregates and the like, the coating film surface is smooth, and it is possible to effectively impart design properties to the structure surface. .

The content of the acrylic silicone contained in the film-forming polymer is usually determined so that the Si content of the film-forming polymer falls within the above-mentioned predetermined range. On the other hand, pigments are usually inorganic substances such as inorganic oxides, and thus have relatively low affinity for the adhesive of the paper. Therefore, in the case of the coating agent as a peelable coloring paint, the amount of acrylic silicone contained in the film-forming polymer can be relatively reduced as compared with the case of the coating agent that forms the light-transmitting coating film described above. it can.

As the pigment, those used in ordinary aqueous paints can be used as they are. The proportion of the pigment contained in the whole paint is usually 10 to 50% by mass, preferably 15 to 3% by mass.
0% by mass. The particle size of the pigment is usually 0.1 to
It is 200 μm, preferably 0.5 to 100 μm.

(4) Coating Agent The coating agent of the present invention can be produced by stirring and mixing a film-forming polymer, various additives, and a medium with a mixer such as a high-speed mixer or a homomixer. The coating agent thus produced can be applied to the surface of the structure using, for example, a brush or a roller.

The solid content concentration with respect to the total mass of the coating agent is preferably 5 to 70% by mass,
The content is more preferably 60% by mass, and particularly preferably 15 to 50% by mass. If the solid content is too low, it becomes difficult to form a coating film with a sufficient thickness, and the drying speed is reduced, or dripping easily occurs when applied to a vertical surface of the structure. is there. On the other hand, if the solid content is too high, it is not preferable in that the coating operation itself becomes difficult.

As a coating agent, a coating film is formed when applied to the surface of a structure and dried (that is, film formation).
There is a lower temperature limit at which the film formation can be performed, and in this specification, the lower temperature limit is referred to as a “minimum film forming temperature (hereinafter referred to as“ MFT ”)”.
Called. For example, when a coating agent having an MFT of 15 ° C. or more is applied and dried in a use environment lower than the MFT, such as when the coating agent is applied outdoors in winter, film formation becomes extremely difficult, and the coating film cracks in a flake shape. It easily peels off from the surface.

Therefore, it is necessary to design the MFT of the coating agent to be compatible with the environment in which the coating agent is used. Assuming that the outdoor construction is performed in winter as described above, the MFT is preferably 5 ° C. or less. The MFT of the coating agent can be controlled by adjusting the type and blending ratio of the acrylic monomer as a starting material of the acrylic silicone main chain, as in the case of the main chain Tg, or by adding a film forming aid. It is.

The coating agent of the present invention preferably has a thickness of 5 to 1000 μm, more preferably has a thickness of 5 to 500 μm, and more preferably has a thickness of 10 to 250 μm. Is particularly preferred.
If the dried coating film formed is too thin, or if the surface of the structure to be coated is porous, or if there are minute irregularities, the coating may not be able to follow the irregularities on the surface of the structure, If it is too much, it is not preferable from the viewpoint of work, for example, it is necessary to apply a coating agent repeatedly.

When the coating agent of the present invention is applied to the surface of the structure, the film-forming polymer forms a dry coating film and imparts releasability to the adhesive for paper. Since the coating agent of the present invention can impart high releasability by the film-forming polymer itself, the addition of aggregate particles for reducing the true contact area is unnecessary, and the aesthetic appearance of the structure surface is not impaired. Further, since the adhesion of the dried coating film to the surface of the structure is good, the dried coating film is not easily peeled off by an action such as scratching with a nail.

In the coating agent of the present invention, the coating film is light-transmitting when no pigment is contained. The light transmittance of the coating film is preferably 50% or more, and preferably 60% or more, as measured by a spectrophotometer using light of 550 nm.
More preferably, it is the above.

The coating film formed from the coating agent of the present invention has good releasability to any of general-purpose adhesives such as acrylics, rubbers, silicones, and urethanes, or pressure-sensitive adhesives. Demonstrate.

As described above, the coating agent of the present invention has an effect of preventing a paper from being stuck on the surface of a structure. Another embodiment is the use as a bulletin board. That is, a coating film is formed by applying and drying a coating agent on the surface of a structure such as an outer wall of a building, and the dried coating film is used as a bulletin board. This is because the coating agent of the present invention does not contain aggregate particles and the surface of the dried coating film is smooth, so that the posted matter can be stuck and easily peeled off. According to such a method, it is not necessary to separately install a bulletin board.

[0053]

EXAMPLES Hereinafter, the effects of the coating agent of the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples. In Examples, six types of coating agents shown in Table 1 were prepared, and the effects of Si content, main chain Tg, MFT, and viscosity were evaluated. In addition, each of the coating agents A to F is an aqueous dispersion composed of only acrylic silicone whose film-forming polymer has an Si content of 5 to 65% by mass as measured by H-NMR, and a film-forming aid and a thickener. It does not contain additives such as

[0054]

[Table 1]

Example 1 25 mm × 10 mm × 100
The weight of the dried coating film is 20
A coating agent was applied using a brush so as to be ５０50 g / m ² , dried in an oven at 60 ° C. for 2 hours, and left overnight to form a dry coating film.

An adhesive filament tape (manufactured by 3M, product number # 898) is attached to the surface of the formed dried coating film,
Five reciprocations were performed with a roller having a mass of 2 kg, and pressure was applied. After curing under conditions of normal temperature (about 25 ° C.) / 30 minutes and 50 ° C./3 days, a 180 ° peel test was performed at a tensile speed of 300 mm / min to evaluate the peel strength.

Coating agent A as coating agent
Was used in Example 1-1, the one using the coating agent B was Example 1-2, and the one using no coating agent was Comparative Example 1-1. Table 2 shows the results.
Shown in

[0058]

[Table 2]

As shown in Table 2, the Si content was 5 to 5.
In Examples 1-1 and 1-2 in which a coating film was formed using a coating agent in the range of 65% by mass, the peel strength was 1000.
g / 25 mm, which was low, and the adhered pressure-sensitive adhesive tape could be easily peeled off without transferring the pressure-sensitive adhesive to the surface of the mortar test piece. In addition, compared with Example 1-1, S
In Example 1-2 having a small i content, the releasability at room temperature / 30 minutes and the releasability after aging at 50 ° C. for 3 days were slightly lowered.

On the other hand, Comparative Example 1 in which no coating film was formed
In Example 1, the peel strength was 1000 g /
As high as more than 25 mm, it was difficult to peel off the adhered adhesive tape. After aging at 50 ° C. for 3 days, the tape was broken when the adhered adhesive tape was to be peeled, and the tape could not be peeled.

(Example 2) A coating agent was applied to the surface of a steel sheet using a brush so that the weight of the dried coating film became 20 to 50 g / m ^2, and dried in an oven at 60 ° C for 2 hours.
A dry coating film was formed by leaving it to stand overnight. The adhesiveness between the surface of the steel sheet and the dried coating was evaluated based on the degree of peeling when the formed dried coating was scratched with a nail.

Coating agent C as coating agent
Example 2 using the coating agent, Example 2-2 using the coating agent D, Example 2-3 using the coating agent A, and Example 2 using the coating agent E. -4, Example 2-5 using coating agent F. Table 3 shows the results.

[0063]

[Table 3]

As shown in Table 3, the main chain Tg was 60 ° C.
In Examples 2-2 to 2-5 below, the adhesion between the steel plate and the dried coating film was good, and the dried coating film did not peel off even when scratched with a nail. On the other hand, in Example 2-1 in which the main chain Tg exceeded 60 ° C., the coating film was brittle and peeled off from the steel sheet surface when scratched with a nail.

Example 3 Under a low temperature environment of 5 ° C., a coating agent was applied to the surface of a steel sheet using a brush so that the mass of the dry coating film became 20 to 50 g / m ² ,
At room temperature overnight to form a dry coating film.
The coatability in a low temperature environment was evaluated by observing the state of the dried coating film after standing overnight.

Coating agent A as coating agent
Was used as Example 3-1 and that using coating agent B was referred to as Example 3-2. Table 4 shows the results.

[0067]

[Table 4]

As shown in Table 4, the MFT was 0 to 5 ° C.
In Example 3-2, film formation was possible even in a low temperature environment of 5 ° C., and a film-like dry coating film could be formed. On the other hand, for Example 3-1 in which the MFT exceeded 15 ° C., the dried coating film cracked in a flake shape,
It easily peeled off from the steel sheet surface.

(Example 4) The coating agent was applied to the vertical surface of the structure with a brush, and the dripping of the coating agent was evaluated by observing the state of the undried coating film immediately after application. Example 4-1 was prepared using the coating agent A as the coating agent, and the amount of the ammonia-modified polyacrylic acid (part number: AES60; ROHM
And Haas Co.) was added to Example 4-2. Table 5 shows the results.

[0070]

[Table 5]

As shown in Table 5, Example 4-2 in which the viscosity measured by a B-type viscometer was 3000 mPa · sec.
As a result, a uniform coating film could be formed without sagging. On the other hand, Example 4-1 having a viscosity of 30 mPa · s
In this case, sagging occurred and it was difficult to form a coating film.

(Example 5) In accordance with the method of Example 1, coating agents A to F were applied to the surface of a mortar test piece having characters and figures drawn with black ink on the surface to form a dried coating film. The coating film formed with any of the coating agents was colorless and transparent and had light transmittance, and characters and figures on the surface of the test piece could be visually recognized through the coating film. That is, the appearance of the mortar test piece surface was not impaired.

(Example 6) According to the method of Example 1, a dried coating film of a peelable coating agent containing acrylic silicone and a pigment and usable as a coloring paint was formed on the surface of a mortar test piece. The peel strength was evaluated in the same manner as in Example 1. However, the curing condition was only room temperature (about 25 ° C.) / 30 minutes.

The coating agents were commercially available water-based paints A to D shown in Table 6 (without acrylic silicone),
The coating agent A is mixed with a film-forming polymer (a mixture of an acrylic silicone and a polymer containing no silicone) contained in the peelable coloring coating agent so that the Si content is 30.
It was prepared by mixing so as to be mass%. Example 6-1 using water-based paint A as water-based paint, water-based paint B
Was used as Example 6-2, the one using water-based paint C was Example 6-3, and the one using water-based paint D was Example 6-4. Table 7 shows the results.

[0075]

[Table 6]

[0076]

[Table 7]

As shown in Table 7, Examples 6-1 to 6
In any of the cases of No. -4, the pressure-sensitive adhesive tape could be easily peeled from the coating film surface without peeling off the dried coating film. For comparison, the peel strength was similarly evaluated for coating films formed using only the aqueous coloring paints A to D without mixing the coating agent A. As a result, in all of the aqueous coloring paints, the closer the pressure-sensitive adhesive tape and the coating film were to each other, the higher the peel strength was. When the pressure-sensitive adhesive tape was to be peeled, all or part of the coating film was peeled off.

[0078]

As described above, the releasable coating agent of the present invention is excellent in adhesiveness to the surface of a structure, releasability to a pressure-sensitive adhesive for pasting paper, and applicability, and aesthetic appearance of the surface of a structure. Does not impair. Further, since no organic solvent is used as a medium, odor due to the solvent does not pose a problem during construction, and the load on the environment is small.

Claims (4)

[Claims] Claims: 1. A film-forming polymer, comprising an aqueous medium,
In a peelable coating agent for forming a peelable and light-transmitting coating film on a structure surface, the film-forming polymer contains acrylic silicone, and the Si content of the film-forming polymer is 5 to 5. 65% by mass
A releasable coating agent, characterized in that: 2. The releasable coating agent according to claim 1, wherein the coating agent further contains a film-forming auxiliary. 3. The releasable coating agent according to claim 1, wherein the minimum film forming temperature of the coating agent is 5 ° C. or lower. 4. A peelable coating agent containing a film-forming polymer, an aqueous medium, and a pigment, which can be used as a coloring paint for forming a peelable colored coating film on the surface of a structure. The film-forming polymer contains acrylic silicone, and the Si content of the film-forming polymer is 5 to 65% by mass.
A releasable coating agent, characterized in that: