Marking film

Abstract

To provide a marking film that can easily remove an adhesive from an adherend without using an organic solvent.SOLUTION: A marking film has a substrate and an adhesive layer. The adhesive layer comprises a water-soluble compound including a polar functional group selected from the group consisting of a hydroxy group, an amino group, a carbonyl group and a benzoyl group and having a molecular weight of 1000 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a marking film.

Background Art

[0002] For the purposes of outdoor billboards, outdoor signs, outdoor advertisements, vehicle advertisements, etc., an adhesive film called a marking film is used. The marking film has a configuration in which an adhesive layer is laminated on one side of a base film, and by bonding the adhesive layer surface to a billboard, a building, a vehicle, etc., an advertising effect can be brought about by the color, characters, images, etc. applied to the base film.

[0003] Since the marking film may be used for advertising and promotional purposes as described above, it may be necessary to reattach it to another marking film after a certain period of time. At this time, it is necessary to peel the marking film from the adherend, but since the adhesive of the marking film has relatively strong adhesiveness, it is not easy to peel the marking film from the adherend. Furthermore, adhesive may remain on the surface of the adherend when peeling the marking film from the adherend.

[0004] In Patent Document 1, it is stated that by laminating an acrylic white adhesive containing a specific polymer on a colored base film and improving the adhesion between the colored film layer and the adhesive layer, it is possible to peel off without leaving an adhesive component on the adherend. Thus, the remaining of the adhesive on the adherend, so-called glue residue, has been studied heretofore.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Especially after a long period of time has passed, or when exposed to high temperatures such as in a place directly under the sun, when trying to peel off the marking film from the adherend, the adhesive may remain on the surface of the adherend. In such cases, it was necessary to remove the adhesive on the adherend, for example, by wiping it off using an organic solvent.

[0007] However, when using an organic solvent, there is a possibility that the paint on the signboard or vehicle, which is the adherend, may peel off, and the use of an organic solvent is a problem that needs to be considered.

[0008] Therefore, an object of the present invention is to provide a marking film that can be easily peeled off from an adherend without using an organic solvent. Another object of the present invention is to provide a marking film that can easily remove the adhesive from the adherend without using an organic solvent.

Means for Solving the Problems

[0009] The present invention is a marking film having a base material and an adhesive layer, wherein the adhesive layer has a polar functional group selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, and a benzoyl group, and contains a water-soluble compound having a molecular weight of 1000 or less.

Effects of the Invention

[0010] According to the marking film of the present invention, it can be easily peeled off from the adherend using an aqueous solvent. Further, according to the marking film of the present invention, the adhesive remaining on the adherend can be easily removed using an aqueous solvent.

Brief Description of the Drawings

[0011]

Figure 1

Modes for Carrying Out the Invention

[0012] Hereinafter, the present embodiment will be described in detail.

[0013] In this specification, "X to Y" indicating a range means "X or more and Y or less". Also, unless otherwise specified, operations, physical properties, etc. are measured under the conditions of room temperature (20 to 25°C) / relative humidity 45 to 55%RH. In this specification, "(meth)acrylate" refers to "acrylate or methacrylate", and "(meth)acrylic acid" refers to "acrylic acid or methacrylic acid".

[0014] The first embodiment of the present invention is a marking film having a base material and an adhesive layer, wherein the adhesive layer has a polar functional group selected from the group consisting of a hydroxyl group, an amino group, a carbonyl group, and a benzoyl group, and contains a water-soluble compound having a molecular weight of 1000 or less.

[0015] It is considered that the water-soluble compound contained in the adhesive layer in the marking film of the first embodiment reduces the cohesive force of the adhesive when it comes into contact with an aqueous solvent by wiping with water or spraying, etc., and makes it easier to peel the adhesive from the adherend.

[0016] Therefore, the marking film of the first embodiment can be easily peeled from the adherend using an aqueous solvent. Also, even if the adhesive remains on the surface of the adherend after peeling the marking film from the adherend, it can be easily removed (for example, by wiping) with an aqueous solvent. Hereinafter, the film property of being easily peeled from the adherend with an aqueous solvent is also referred to as the water-peeling property. Also, hereinafter, the adhesive property of being easily removed (for example, by wiping) from the adherend with an aqueous solvent is also referred to as the water-removing property.

[0017] Figure 1 is a schematic cross-sectional view showing a marking film. In Figure 1, the marking film 10 is composed of a base material 11, an adhesive layer 12, and a release liner 13. The base material 11 is disposed adjacent to the adhesive layer 12. When pasting, the release liner 13 is removed from the marking film 10, and the marking film is pasted on the adherend with the exposed adhesive layer 12.

[0018] In FIG. 1, it is a laminate having a base material 11, an adhesive layer 12, and a release liner 13 in this order. However, as long as the adhesive layer is exposed when attached to the adherend, other intermediate layers may be present on the base material and / or between the base material and the adhesive layer.

[0019] The marking film preferably has an adhesive strength of 2 N / 25 mm or more, more preferably 4 N / 25 mm or more, and even more preferably 5 N / 25 mm or more. By the adhesive strength of the marking film being above the above lower limit, the adhesiveness to the adherend is ensured. The marking film needs to be attached to the adherend for a long time and requires a certain degree of adhesiveness. The upper limit of the adhesive strength is not particularly limited, but it is 15 N / 25 mm or less. In addition, the value of the adhesive strength measured by the method described in the following examples is adopted.

[0020] Hereinafter, each component constituting the marking film will be described.

[0021] [Adhesive layer] The adhesive layer contains an adhesive and a water-soluble compound having a polar functional group (hereinafter also simply referred to as a water-soluble compound). Here, water-soluble refers to a compound that dissolves 1 g or more, preferably 3 g or more, and more preferably 10 g or more in 100 g of water (25 °C).

[0022] The polar functional groups in the water-soluble compound are a hydroxyl group, an amino group, a carbonyl group, and a benzoyl group. Among them, since the water removal characteristics of the adhesive remaining on the adherend are improved, the polar functional group is preferably a hydroxyl group or an amino group, and more preferably a hydroxyl group.

[0023] Examples of the compound having an amino group include polyethyleneimine, propylene oxide-modified polyethyleneimine, polyvinylamine, and the like.

[0024] Examples of the compound having a carbonyl group include 2-pyrrolidone, triethyl citrate, and the like.

[0025] As the water-soluble compound having a salicylic acid group, a polyhydric alcohol or a polyhydric alcohol derivative is preferable because the water-peeling property from the adherend and / or the water-removing property of the adhesive remaining on the adherend is further improved.

[0026] Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tripropylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butylene glycol, polyethylene glycol, glycerin, diglycerin, polyglycerin, pentanediol, hexamethylene glycol and the like. These may be used alone or in combination of two or more. Among them, the polyhydric alcohol is preferably at least one selected from the group consisting of ethylene glycol, triethylene glycol, polyethylene glycol, and glycerin.

[0027] Examples of the polyhydric alcohol derivative include polyhydric alcohol monoalkyl ethers (polyhydric alcohol ethers) having a hydroxyl group such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, and ethylene glycol monoethyl ether.

[0028] Further, as the water-soluble compound, at least one selected from the group consisting of a polyhydric alcohol, a polyhydric alcohol derivative, and polyethyleneimine is preferable because the water-peeling property from the adherend and / or the water-removing property of the adhesive remaining on the adherend is further improved. Further, from the viewpoint of improving adhesiveness, the water-soluble compound is more preferably a polyhydric alcohol.

[0029] The molecular weight of the water-soluble compound is 1000 or less. If the molecular weight of the water-soluble compound exceeds 1000, its solubility in water decreases, resulting in a decline in the water-peeling property and / or water-removing property. Preferably, the molecular weight of the water-soluble compound is 800 or less, and more preferably 500 or less. The lower limit of the molecular weight of the water-soluble compound is usually 30 or more, and may be 50 or more.

[0030] The water-soluble compound may be used alone or in combination of two or more.

[0031] The addition amount of the water-soluble compound is appropriately set according to the type of the adhesive used, the type of the water-soluble compound, etc. Since the effects of the water-peeling property and / or water-wiping property are further exerted, the addition amount of the water-soluble compound is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 3% by mass or more based on the adhesive (for example, an acrylic copolymer). Also, from the viewpoint of adhesiveness, the addition amount of the water-soluble compound is preferably 30% by mass or less, and more preferably 25% by mass or less based on the adhesive (for example, an acrylic copolymer).

[0032] There is no particular limitation on the adhesive, and for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyurethane adhesive, a polyester adhesive, etc. can be used. From the viewpoint of the reliability of adhesion, an acrylic adhesive can be particularly preferably used.

[0033] The acrylic copolymer constituting the acrylic adhesive is formed by using (meth)acrylic acid alkyl ester as the main monomer component and, if necessary, a monomer copolymerizable with the (meth)acrylic acid alkyl ester (copolymerizable monomer). Here, the main component means 50% by mass or more (upper limit 100% by mass) in the monomer, preferably 65% by mass or more, and more preferably 85% by mass or more.

[0034] Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and the like. These may be used alone or in combination of two or more. Among them, as the (meth)acrylic acid alkyl, considering the adhesiveness, it is preferable to use n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate, more preferably 2-ethylhexyl (meth)acrylate, and even more preferably 2-ethylhexyl acrylate because sufficient adhesive strength can be obtained even in a low-temperature environment. When using n-butyl (meth)acrylate and / or 2-ethylhexyl (meth)acrylate, it is preferably 70 to 97% by mass, more preferably 80 to 95% by mass, based on the total amount of the monomers.

[0035] Also, from the viewpoint of tackiness, it is preferable to use methyl (meth)acrylate in combination with n-butyl (meth)acrylate and / or 2-ethylhexyl (meth)acrylate, and more preferably to combine methyl methacrylate. The content of methyl (meth)acrylate is preferably 0.5 to 25% by mass, more preferably 1 to 20% by mass, and even more preferably 5 to 20% by mass, based on the total amount of the monomers.

[0036] Examples of copolymerizable monomers copolymerizable with (meth)acrylic acid alkyl esters include carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, or their anhydrides; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and hydroxyl group-containing monomers such as glycerin dimethacrylate; amide group-containing monomers such as acrylamide, methacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide; amino group-containing monomers such as aminoethyl (meth)acrylate, (meth)acryloylmorpholine; aromatic vinyl compounds such as styrene and substituted styrene; cyano group-containing monomers such as acrylonitrile; vinyl esters such as vinyl acetate, etc. These may be used alone or in combination of two or more.

[0037] Among them, since the dispersion stability in the emulsion polymer in a preferred form is improved, it is preferable to use a carboxyl group-containing monomer or its anhydride as the copolymerizable monomer copolymerizable with the (meth)acrylic acid alkyl ester. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, myristoleic acid, palmitoleic acid, and oleic acid. Examples of the anhydride of the carboxyl group-containing monomer include maleic anhydride and itaconic anhydride. Among them, it is more preferable to use (meth)acrylic acid as the copolymerizable monomer copolymerizable with the (meth)acrylic acid alkyl ester, and it is even more preferable to use acrylic acid.

[0038] When using a carboxyl group-containing monomer or its anhydride, its content in the total monomers is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, and even more preferably 1 to 5% by mass.

[0039] The content in the pressure-sensitive adhesive layer of the acrylic copolymer is preferably 50 to 99.5% by mass, more preferably 60 to 99% by mass, and even more preferably 80 to 97% by mass.

[0040] The method for producing the acrylic copolymer is not particularly limited, and conventionally known methods such as solution polymerization method, emulsion polymerization method, suspension polymerization method, inverse suspension polymerization method, thin film polymerization method, spray polymerization method, etc. using a polymerization initiator can be used. In addition to the method of initiating polymerization with a polymerization initiator, a method of initiating polymerization by irradiating radiation, electron beams, ultraviolet rays, etc. can also be adopted. Among them, since the effects of the present invention are further exerted, it is preferable to use the emulsion polymerization method. That is, in a preferred embodiment of the present invention, the acrylic copolymer is an emulsion polymer.

[0041] When the acrylic copolymer is an emulsion polymer, it is preferably not crosslinked by a crosslinking agent. That is, preferably, the acrylic copolymer is a non-crosslinked product.

[0042] Examples of the emulsion polymerization method include a method of adding an emulsifier and a polymerization initiator to a monomer mixture containing the above-mentioned monomers and performing emulsion polymerization.

[0043] In addition, in emulsion polymerization, from the viewpoint of polymerization stability, it is preferable that the monomer mixture dissolves the emulsifier (or a part of the emulsifier) in the monomer mixture or is previously in the state of an O / W type emulsion.

[0044] Examples of the procedure for performing emulsion polymerization include the following methods (1) to (3). (1) Charge the total amounts of the monomer mixture, emulsifier, water, etc., raise the temperature, and dropwise add or divide and add the total amount of the polymerization initiator dissolved in water to carry out polymerization. (2) Charge water, emulsifier, and a part of the monomer mixture into the reaction vessel, raise the temperature, then dropwise add or divide and add the polymerization initiator dissolved in water to allow the polymerization reaction to proceed, and then dropwise add or divide and add the remaining monomer mixture in total amount to continue the polymerization. (3) After charging a polymerization initiator dissolved in water into the reaction vessel and raising the temperature, the entire amount of an emulsion consisting of a monomer mixture, an emulsifier, and water is added dropwise or in portions and polymerized.

[0045] The emulsifier is not particularly limited, but from the viewpoint of improving the dispersion stability of the emulsion polymer, an anionic emulsifier or a nonionic emulsifier is preferable, and an anionic emulsifier is more preferable.

[0046] Examples of the anionic emulsifier include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl ether sulfate ester, allyl alkyl sulfosuccinate ester salt, and the like. Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and the like. These emulsifiers may be used alone or in combination of two or more.

[0047] From the viewpoint of the stability of the emulsion polymerization reaction and preventing the deterioration of physical properties due to the remaining unreacted emulsifier, the addition amount of the emulsifier is preferably 0.5 to 12 parts by mass, more preferably 0.5 to 8 parts by mass, and still more preferably 0.7 to 6 parts by mass with respect to 100 parts by mass of the monomer mixture.

[0048] The emulsifier may be added directly to a solution obtained by adding water to the monomer mixture, may be added to the polymerization vessel in advance, or they may be used in combination.

[0049] The polymerization initiator may be either water-soluble or oil-soluble. Examples include azo compounds such as 2,2'-azobis(2-methylpropionamidine) dihydrochloride and 2,2'-azobis(2-amidinopropane) dihydrochloride, persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate, and peroxides such as benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide. A redox initiator composed of a combination of a persulfate and sodium bisulfite, or a combination of a peroxide and sodium ascorbate, etc. may also be used. The polymerization initiator may be used alone or in combination of two or more. Among these, from the viewpoint of excellent polymerization stability, persulfates or redox initiators are preferred.

[0050] From the viewpoint of accelerating the polymerization rate, the addition amount of the polymerization initiator is preferably 0.01 to 6 parts by mass, more preferably 0.03 to 4 parts by mass, and still more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the monomer mixture.

[0051] In addition, the polymerization initiator may be added to the reaction vessel in advance, may be added immediately before the start of polymerization, may be added in multiple portions after the start of polymerization, may be added to the monomer mixture in advance, or may be added to the emulsion prepared from the monomer mixture.

[0052] Further, a known chain transfer agent or pH buffer may be added during emulsion polymerization.

[0053] For emulsion polymerization, ion-exchanged water is preferably used as the water. The amount of water used is preferably 30 to 400 parts by mass, more preferably 35 to 200 parts by mass, and still more preferably 40 to 150 parts by mass with respect to 100 parts by mass of the monomer mixture.

[0054] It is preferable to add an alkaline aqueous solution such as aqueous ammonia, various water-soluble amines, an aqueous sodium hydroxide solution, or an aqueous potassium hydroxide solution to the emulsion polymer dispersion obtained by emulsion polymerization and adjust the pH to 5 to 9 (preferably pH 6 to 8.5).

[0055] The solid content concentration of the emulsion polymer dispersion is preferably 10 to 80% by mass, more preferably 25 to 70% by mass, and still more preferably 45 to 65% by mass.

[0056] The viscosity of the emulsion polymer dispersion at 25°C is preferably 50 to 12000 mPa·s, more preferably 100 to 10000 mPa·s, and still more preferably 200 to 9000 mPa·s. In this specification, the viscosity is a value measured using a B-type rotational viscometer.

[0057] The emulsion polymer has an emulsion shape (particle shape) in which the emulsion polymer is dispersed. At this time, the average particle diameter of the emulsion polymer is preferably 500 nm or less, more preferably 300 nm or less, and still more preferably 200 nm or less. Also, the average particle diameter of the emulsion polymer is usually 50 nm or more, and more preferably 100 nm or more. Here, the average particle diameter of the emulsion polymer is the volume-based median diameter measured by the laser diffraction scattering method.

[0058] The pressure-sensitive adhesive layer may contain a tackifier. The tackifier is not particularly limited, and examples thereof include alicyclic petroleum resins, terpene resins, polymerized rosin ester resins, and styrene resins.

[0059] The pressure-sensitive adhesive layer may further contain other conventionally known additives. Examples of such additives include fillers, pigments, and ultraviolet absorbers. Examples of the filler include zinc white, silica, and calcium carbonate.

[0060] The method for forming the adhesive layer is not particularly limited. However, the adhesive composition for forming the adhesive layer (hereinafter, also simply referred to as the adhesive composition) may be directly applied onto the substrate to form the adhesive layer, or the adhesive layer may be formed on the release liner and then laminated onto the substrate. Specifically, a method of applying the adhesive composition onto the release liner and transferring the adhesive layer composed of the adhesive composition onto the substrate can be mentioned.

[0061] The method for applying the adhesive composition onto the substrate or the release liner is not particularly limited. For example, it can be applied using known coating apparatuses such as a roll coater, a knife coater, an air knife coater, a bar coater, a blade coater, a slot die coater, a lip coater, a gravure coater, etc.

[0062] The thickness of the adhesive layer (film thickness after drying) is usually 5 to 100 μm, preferably 10 to 50 μm.

[0063] <Substrate> The substrate is not particularly limited. For example, paper substrates such as kraft paper and Japanese paper, resin substrates, synthetic paper, etc. can be mentioned. Among these, from the viewpoint of durability, the substrate is preferably a resin substrate.

[0064] Examples of the resin constituting the resin substrate include olefin resins having α-olefins such as polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), etc. as monomer components; polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.; polyvinyl chloride (PVC); vinyl acetate resins; polycarbonate (PC); acrylic resins; polyurethanes, etc. These resins may be used alone or in combination of two or more. Among these, from the viewpoints of weather resistance and flexibility, the resin constituting the resin substrate is preferably polyvinyl chloride, acrylic resin, or polyurethane.

[0065] Examples of the synthetic paper include a polyester film and a polypropylene film having fine voids.

[0066] The thickness of the base material is appropriately selected depending on the type of the base material used, but is preferably 10 to 200 μm, more preferably 20 to 150 μm, and even more preferably 30 to 100 μm.

[0067] The base material may be transparent or opaque.

[0068] Further, the base material may be colored or colorless. In the case of being colored, any colorant can be used. The production of the colored base material can be carried out by blending a colorant with the resin of the raw material, melt-kneading and molding it into a film, or by a casting film-forming method in which it is cast on a process film, dried and molded.

[0069] Various additives such as an ultraviolet absorber, a plasticizer, a heat stabilizer, a dispersion solvent, and a dilution dispersion solvent can be contained in the base material. Examples of the ultraviolet absorber include salicylic acid-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and triazole-based ultraviolet absorbers. Examples of the plasticizer include phosphate-based plasticizers, phthalate-based plasticizers, adipic acid-based plasticizers, and polyester-based plasticizers. Examples of the heat stabilizer include lead salt-based heat stabilizers, metal soap-based heat stabilizers, and organotin compound-based heat stabilizers. Examples of the dispersion solvent include ketones such as diisobutyl ketone and methyl isobutyl ketone, esters such as butyl acetate, and glycol ethers such as butyl cellosolve. Further, examples of the dilution dispersion solvent include paraffinic hydrocarbons, naphthenic hydrocarbons, aromatic hydrocarbons, and terpenes.

[0070] When an adhesive layer is provided on one side of the base material, one side of the base material may be surface-treated in order to improve the adhesion to the adhesive layer. Examples of the surface treatment include corona discharge treatment, plasma treatment, and primer treatment.

[0071] <Release Liner> The marking film may include a release liner. The release liner is a member that is used before attaching the adhesive film to the adherend, protects the adhesive layer, and has the function of preventing a decrease in adhesiveness before use.

[0072] The release liner is not particularly limited, but examples include plastic films such as polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene; and papers such as high-quality paper, glassine paper, kraft paper, and clay-coated paper.

[0073] There is no particular limitation on the thickness of the release liner, but it is usually 10 to 400 μm. Further, a layer composed of a release agent composed of silicone or the like for improving the releasability from the adhesive layer may be provided on the surface of the release liner.

[0074] <Uses of the Marking Film> On the surface of the base material 11 of the marking film 10 according to an embodiment of the present invention that is not in contact with the adhesive layer 12, colors and patterns may be applied by a method such as inkjet printing through an ink-receiving layer or the like as necessary. For such a marking film, by removing the release liner 13 and attaching the exposed surface of the adhesive layer 12 to the surface of the adherend, the colors and patterns applied to the base material 11 can be presented on the adherend while concealing the colors and patterns of the adherend. Further, the adherend to which this marking film is attached can have the marking film easily peeled off from the adherend by an aqueous medium even after being attached to the outdoor environment for a certain period, and also, even if an adhesive remains on the adherend after peeling the marking film from the adherend, the adhesive can be easily removed by wiping with water. Therefore, the marking film according to an embodiment of the present invention can be suitably used for the purpose of decorating adherends (such as signboards, advertisements, vehicles, buildings, traffic signs, etc.) used outdoors for a certain period.

[0075] <Method for Peeling a Marking Film from an Adherend> The second embodiment of the present invention is a method for peeling a film from an adherend using an aqueous solvent, which is a method for peeling a marking film from an adherend. The marking film of the first embodiment has an adhesive layer containing a water-soluble compound having a polar functional group and a molecular weight of 1000 or less. Therefore, by using an aqueous solvent, the marking film can be easily and simply peeled from the adherend (without using an organic solvent that affects painting, etc.).

[0076] The aqueous solvent refers to a solvent containing 60% by mass or more (upper limit 100% by mass) of water, preferably 70% by mass or more, more preferably 85% by mass or more, and most preferably the aqueous solvent is water.

[0077] Examples of components other than water contained in the aqueous solvent include organic solvents soluble in water and surfactants. Examples of organic solvents soluble in water include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, dimethylformamide, methyl cellosolve, and tetrahydrofuran.

[0078] Examples of the method for peeling the marking film from the adherend include a method of slightly peeling the marking film from the adherend and peeling it while spraying the aqueous solvent on the interface between the marking film and the adherend. In the case of spraying the aqueous solvent, the aqueous solvent may be sprayed at high pressure.

[0079] <Method for Removing Adhesive> The third embodiment of the present invention is a method for removing the adhesive from the adherend using an aqueous solvent when the adhesive of the marking film of the first embodiment remains on the adherend. As described above, the marking film of the first embodiment can be easily peeled from the adherend using an aqueous solvent, but even when the adhesive remains on the surface of the adherend, it has excellent water removal characteristics.

[0080] As the aqueous solvent, the same one as described in the column of the second embodiment can be used.

[0081] As a method for removing an adhesive from an adherend using an aqueous solvent, specifically, wiping the adherend surface with a cloth or non-woven fabric containing the aqueous solvent; spraying the aqueous solvent under high pressure, etc. can be mentioned.

Example

[0082] The effects of the present invention will be described using the following examples and comparative examples. Although the display of "parts" or "%" may be used in the examples, unless otherwise specified, it represents "parts by mass" or "mass%". Also, unless otherwise specified, each operation is performed at room temperature (25°C).

[0083] (Example 1) Into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, 84 parts by mass of 2-ethylhexyl acrylate, 12.5 parts by mass of methyl methacrylate, and 3.5 parts by mass of acrylic acid as raw material monomers, and 4 parts by mass (0.96 parts by mass in terms of solid content) of sodium lauryl sulfate ("Emal AD-25R" manufactured by Kao Corporation) as an emulsifier and 35 parts by mass of deaerated ion-exchanged water were charged and stirred to prepare an emulsion.

[0084] Separately, 40 parts by mass of deaerated ion-exchanged water was charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, and the temperature was raised to 80°C. Next, the emulsion was transferred to the dropping funnel and dropped over 4 hours. In parallel with this, 4 parts by mass of an aqueous solution of potassium persulfate with a concentration of 3% by mass as a polymerization initiator solution was dropped, and emulsion polymerization was carried out at a reaction temperature of 80°C. After the dropping was completed, it was aged at 80°C for 2 hours to obtain an emulsion polymerization composition. Then, it was cooled to room temperature and adjusted to a pH of 7.0 with 25% by mass of aqueous ammonia and 25% by mass of an aqueous sodium hydroxide solution to obtain an aqueous dispersion of an acrylic polymer.

[0085] 1 part by mass of ethylene glycol was added to 100 parts by mass in terms of solid content of the obtained aqueous acrylic polymer solution to obtain an adhesive composition.

[0086] The obtained pressure-sensitive adhesive composition was applied onto the release agent-coated surface of a release liner obtained by applying a silicone-based release agent at a thickness of 0.1 μm onto a polyethylene terephthalate film with a thickness of 38 μm using a knife coater so that the dry film thickness was 15 μm, and then dried at 90°C to obtain a laminate of the release liner and the pressure-sensitive adhesive layer.

[0087] A polyvinyl chloride film with a thickness of 50 μm was used as a base material and laminated to the pressure-sensitive adhesive layer surface of the above laminate to obtain a marking film.

[0088] (Example 2) A marking film was obtained in the same manner as in Example 1, except that the addition amount of ethylene glycol was 10 parts by mass.

[0089] (Example 3) A marking film was obtained in the same manner as in Example 1, except that the addition amount of ethylene glycol was 20 parts by mass.

[0090] (Example 4) A marking film was obtained in the same manner as in Example 2, except that ethylene glycol was changed to triethylene glycol.

[0091] (Example 5) A marking film was obtained in the same manner as in Example 2, except that ethylene glycol was changed to polyethylene glycol (molecular weight 600).

[0092] (Example 6) A marking film was obtained in the same manner as in Example 2, except that ethylene glycol was changed to glycerin.

[0093] (Example 7) A marking film was obtained in the same manner as in Example 2, except that ethylene glycol was changed to polyethyleneimine (molecular weight 600, Epomin SP-006 manufactured by Nippon Shokubai Co., Ltd.).

[0094] (Comparative Example 1) In Example 1, a marking film was obtained in the same manner as in Example 1, except that ethylene glycol was not added.

[0095] (Measurement method: Adhesion) The marking films obtained in the examples and comparative examples were allowed to stand in a standard environment (23°C, 50% RH) for 1 day. After peeling off the release liner and attaching the adhesive layer surface to a SUS plate (SUS304 steel plate), the adhesion was measured. Specifically, using a tensile tester, the sheet was peeled off at a test speed of 300 mm / min in the 180° direction, and the adhesion was measured. The numerical values were converted to the peeling force per 25 mm of sheet width (N / 25 mm). The results are shown in Table 1.

[0096] (Evaluation method: Rubbing test) In the examples and comparative examples, instead of attaching a polyvinyl chloride film, a release liner was attached. One release liner was peeled off, and an adhesive (15 μm) was attached to a melamine-coated plate and allowed to stand in a 40°C environment for 7 days. After peeling off the other release liner, the appearance after wiping the adhesive surface 20 times back and forth with a wiper containing water (Bencot (registered trademark), manufactured by Asahi Kasei Corporation) was evaluated.

[0097] ○: Completely wiped off △: Partially wiped off ×: Unable to wipe off

[0098] (Evaluation method: Ease of peeling when water is sprayed) The marking films obtained in the examples and comparative examples were allowed to stand in a standard environment (23°C, 50% RH) for 1 day. After peeling off the release liner and attaching the adhesive layer surface to a melamine-coated plate, they were allowed to stand in a 40°C environment for 7 days. After peeling off the end of the marking film, while spraying water at a water pressure of 10 MPa onto the interface between the marking film and the adherend, the end was held and peeled off. The ease of peeling at that time was evaluated.

[0099] 〇: Easily peelable △: Difficult but peelable ×: Cannot be peeled off.

[0100] The results are shown in Table 1.

[0101]

Table 1

[0102] As can be seen from the above results, the marking films of Examples 1 to 7 could be easily peeled off from the adherend by water, and the remaining adhesive on the adherend could be removed by wiping with water.

Explanation of reference signs

[0103] 10 Marking film, 11 Substrate, 12 Adhesive layer, 13 Release liner.

Claims

1. A marking film having a base material and an adhesive layer, wherein the adhesive layer contains a water-soluble compound having a polar functional group selected from the group consisting of a hydroxyl group and an amino group and having a molecular weight of 1000 or less, and an acrylic copolymer, the acrylic copolymer is formed by using 80% by mass or more and 97% by mass or less of 2-ethylhexyl (meth)acrylate based on the total amount of monomers, the water-soluble compound is at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tripropylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butylene glycol, glycerin, diglycerin, polyglycerin, pentanediol, hexamethylene glycol, and polyhydric alcohol alkyl ethers thereof, and compounds having an amino group, provided that when the water-soluble compound is propylene glycol, the addition amount is 3% by mass or more based on the acrylic copolymer. A marking film.

2. A marking film having a base material and an adhesive layer, wherein the adhesive layer contains a water-soluble compound having a polar functional group selected from the group consisting of a hydroxyl group and an amino group and having a molecular weight of 1000 or less, and an acrylic copolymer, the acrylic copolymer is formed by using 80% by mass or more and 97% by mass or less of 2-ethylhexyl (meth)acrylate based on the total amount of monomers, the water-soluble compound is at least one selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tripropylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butylene glycol, glycerin, diglycerin, polyglycerin, pentanediol, hexamethylene glycol, and polyhydric alcohol alkyl ethers thereof, and compounds having an amino group, and the addition amount of the water-soluble compound is 3% by mass or more based on the acrylic copolymer. A marking film.

3. The water-soluble compound is ethylene glycol, diethylene glycol, triethylene glycol, tri The marking film according to claim 1 or 2, which is at least one selected from the group consisting of call, tripropylene glycol, propylene glycol, 1,3-propanediol, dipropylene glycol, 1,3-butylene glycol, glycerin, diglycerin, polyglycerin, pentanediol, hexamethylene glycol, and polyhydric alcohol alkyl ethers thereof, and polyethyleneimine.

4. The marking film according to any one of claims 1 to 3, wherein the adhesive layer contains an emulsion-based acrylic copolymer.

5. The marking film according to any one of claims 1 to 4, wherein methyl (meth)acrylate is used in combination with 2-ethylhexyl (meth)acrylate.

6. The marking film according to any one of claims 1 to 5, wherein the substrate is a resin substrate.

7. A method for peeling a marking film from an adherend, the method using an aqueous solvent to peel the marking film from the adherend, the marking film being according to any one of claims 1 to 6.

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