JP2019156970A - Film for marking - Google Patents

Abstract

To provide a film for marking that has a high initial adhesive strength and the adhesive strength is retained high even when used outdoors for a long time, and has an excellent weather resistance.SOLUTION: Provided is a film for marking comprising: a substrate in which an epoxy-based stabilizer, an ultraviolet absorber and a plasticizer are blended to a polyvinyl chloride; a primer layer containing acrylic resin having a primary amino group; and an adhesive layer containing an acryl-based adhesive and an isocyanate-based curing agent, in this order, and in which the isocyanate-based curing agent is blended in an amount of 0.4 pts.wt. or less to 100 pts.wt. of the acryl-based adhesive.SELECTED DRAWING: Figure 1

Description

The present invention relates to a marking film.

The polyvinyl chloride film is sometimes used by being attached to an article for purposes such as marking and repair.

For example, in Patent Document 1, a glass transition point is provided on one side of a soft vinyl chloride resin film containing an ultraviolet absorber via an acrylic ester resin primer layer having a glass transition point of 50 to 100 ° C. An agricultural covering material repair tape is disclosed, in which an acrylic ester resin pressure-sensitive adhesive layer having a temperature of −70 to −30 ° C. is provided, and a dustproof layer is provided on the other surface.

Japanese Patent Laid-Open No. 3-131678

Polyvinyl chloride film is exposed to high-temperature environments (for example, environments exposed to direct sunlight) when used on outdoor articles (for example, factory piping, utility poles, etc.) for marking purposes. The adhesive strength was not maintained for a long time, and discoloration was sometimes observed.

The present invention has been made in view of the above situation, and provides a marking film that has high initial adhesive strength, maintains high adhesive strength even when used outdoors for a long period of time, and has excellent weather resistance. It is for the purpose.

As a marking film, the present inventor uses a base material in which an epoxy stabilizer, an ultraviolet absorber and a plasticizer are blended in polyvinyl chloride, a primer layer containing an acrylic resin having a primary amino group, an acrylic If the amount of the isocyanate curing agent in the pressure-sensitive adhesive layer is within the predetermined range after using the laminate with the pressure-sensitive adhesive and the pressure-sensitive adhesive layer containing the isocyanate-based curing agent, the initial adhesive strength is increased. The inventors have found that the adhesive strength is kept high even when used outdoors for a long period of time and that the weather resistance is enhanced, and the present invention has been completed.

The marking film of the present invention includes a base material in which an epoxy stabilizer, an ultraviolet absorber and a plasticizer are blended with polyvinyl chloride, a primer layer containing an acrylic resin having a primary amino group, and an acrylic adhesive. A pressure-sensitive adhesive layer containing an agent and an isocyanate curing agent, and the isocyanate curing agent is blended in an amount of 0.4 parts by weight or less based on 100 parts by weight of the acrylic pressure-sensitive adhesive. To do.

The ultraviolet absorber is preferably a benzophenone ultraviolet absorber or a benzotriazole ultraviolet absorber.

The ultraviolet absorber is preferably blended in an amount of 0.2 to 2 parts by weight based on 100 parts by weight of the polyvinyl chloride.

According to the marking film of the present invention, it is possible to realize a marking film having high initial adhesive strength, high adhesive strength even when used outdoors for a long period of time, and excellent weather resistance.

It is a cross-sectional schematic diagram which shows an example of the film for marking of this invention.

The marking film of the present invention includes a base material in which an epoxy stabilizer, an ultraviolet absorber and a plasticizer are blended with polyvinyl chloride, a primer layer containing an acrylic resin having a primary amino group, and an acrylic adhesive. A pressure-sensitive adhesive layer containing an agent and an isocyanate curing agent, and the isocyanate curing agent is blended in an amount of 0.4 parts by weight or less based on 100 parts by weight of the acrylic pressure-sensitive adhesive. To do.

In the present specification, “film” is synonymous with “sheet”, and the two are not distinguished by thickness.

In the present specification, “X to Y” means “X or more and Y or less”.

FIG. 1 is a schematic cross-sectional view showing an example of the marking film of the present invention. As shown in FIG. 1, the marking film 1 includes a base material 2, a primer layer 3, and an adhesive layer 4 in order.

<Base material>
The base material 2 is a polyvinyl chloride film in which an epoxy stabilizer, an ultraviolet absorber and a plasticizer are blended.

Since the base material 2 contains polyvinyl chloride, it is easy to stretch and is not easily broken, so that the marking film 1 can be easily attached to a three-dimensional curved surface. Moreover, since the epoxy stabilizer is mix | blended with polyvinyl chloride, the thermal stability of polyvinyl chloride is ensured. Since the epoxy-based stabilizer does not easily migrate to the pressure-sensitive adhesive layer 4, even if it is used outdoors for a long time, the pressure-sensitive adhesive force of the marking film 1 is hardly reduced. Moreover, according to the base material 2, the weather resistance improvement effect by an ultraviolet absorber is also acquired. Furthermore, since the plasticizer is mix | blended with the polyvinyl chloride, the soft polyvinyl chloride film to which the softness | flexibility was provided as the base material 2 is obtained. According to the soft polyvinyl chloride film, the marking film 1 is affixed to a three-dimensional curved surface as compared with a hard polyvinyl chloride film (polyvinyl chloride not containing a plasticizer), a polyethylene terephthalate film, or the like. Is extremely easy.

(PVC)
Examples of polyvinyl chloride include a homopolymer of vinyl chloride, a copolymer of vinyl chloride and other monomers, and the like. Among these, from the viewpoint of dimensional stability, a homopolymer of vinyl chloride is preferable.

When polyvinyl chloride is a copolymer of vinyl chloride and other monomers, examples of other monomers include vinyl esters such as vinyl acetate and vinyl propionate; ethylene, propylene, styrene, and the like. Olefins; (meth) acrylic acid esters such as methyl acrylate, ethyl acrylate and methyl methacrylate; maleic acid diesters such as dibutyl maleate and diethyl maleate; fumaric acid diesters such as dibutyl fumarate and diethyl fumarate; acrylonitrile; And vinyl cyanides such as methacrylonitrile; vinyl halides such as vinylidene chloride and vinyl bromide; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, and the like. These monomers may be used alone or in combination of two or more.

When the polyvinyl chloride is a copolymer of vinyl chloride and another monomer, the content of the other monomer in the copolymer is usually 50% by weight or less, preferably 10% by weight. % Or less. When the content of other monomers is more than 50% by weight, the bending resistance of the substrate 2 may be lowered.

The average degree of polymerization of polyvinyl chloride is appropriately adjusted according to the desired hardness of the substrate 2, the amount of plasticizer used to adjust the hardness, etc., but from the viewpoint of workability, it is preferable. Is 800-1300. In the present specification, “average degree of polymerization of polyvinyl chloride” means an average degree of polymerization measured in accordance with JIS K6721 “Testing method for vinyl chloride resin”.

(Epoxy stabilizer)
The epoxy stabilizer is blended as a stabilizer for polyvinyl chloride, and is preferably an epoxy resin that is solid (powder) at room temperature (about 23 ° C.). If the epoxy-based stabilizer is a solid (powdered) epoxy resin at room temperature, the epoxy-based stabilizer is extremely difficult to migrate to the pressure-sensitive adhesive layer 4 as compared with the case where it is liquid. Even when used for a long period of time, a decrease in the adhesive strength of the marking film 1 is sufficiently suppressed. Examples of such an epoxy stabilizer (epoxy resin) include epoxidized 1,2-polybutadiene, epoxidized fatty acid octyl ester, and the like.

The epoxy stabilizer is preferably blended in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of polyvinyl chloride. When the blending amount of the epoxy stabilizer is less than 0.5 parts by weight, the thermal stability of polyvinyl chloride may not be sufficiently increased. When there are more compounding quantities of an epoxy-type stabilizer than 10 weight part, an epoxy-type stabilizer may transfer to the surface of the base material 2, and may eject.

(UV absorber)
The ultraviolet absorber is preferably a benzophenone ultraviolet absorber or a benzotriazole ultraviolet absorber. Thereby, compatibility with polyvinyl chloride is sufficiently ensured, and the weather resistance of the marking film 1 is further increased.

Examples of benzophenone-based ultraviolet absorbers include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5′-methylenebis (2-hydroxy-4-methoxy). Benzophenone) and the like. These benzophenone ultraviolet absorbers may be used alone or in combination of two or more.

Examples of the benzotriazole ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, and 2- (2-hydroxy- 3,5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy- 3,5-dicumylphenyl) benzotriazole, 2,2′-methylenebis (4-tert-octyl-6-benzotriazolylphenol), 2- (2-hydroxy-3-tert-butyl-5-carboxyphenyl) ) Polyethylene glycol ester of benzotriazole, 2- [2-hydroxy 3- (2-acryloyloxyethyl) -5-methylphenyl] benzotriazole, 2- [2-hydroxy-3- (2-methacryloyloxyethyl) -5-tert-butylphenyl] benzotriazole, 2- [2- Hydroxy-3- (2-methacryloyloxyethyl) -5-tert-octylphenyl] benzotriazole, 2- [2-hydroxy-3- (2-methacryloyloxyethyl) -5-tert-butylphenyl] -5-chloro Benzotriazole, 2- [2-hydroxy-5- (2-methacryloyloxyethyl) phenyl] benzotriazole, 2- [2-hydroxy-3-tert-butyl-5- (2-methacryloyloxyethyl) phenyl] benzotriazole , 2- [2-hydroxy-3-tert Amyl-5- (2-methacryloyloxyethyl) phenyl] benzotriazole, 2- [2-hydroxy-3-tert-butyl-5- (3-methacryloyloxypropyl) phenyl] -5-chlorobenzotriazole, 2- [ 2-hydroxy-4- (2-methacryloyloxymethyl) phenyl] benzotriazole, 2- [2-hydroxy-4- (3-methacryloyloxy-2-hydroxypropyl) phenyl] benzotriazole, 2- [2-hydroxy- 4- (3-methacryloyloxypropyl) phenyl] benzotriazole, and the like. These benzotriazole-based UV absorbers may be used alone or in combination of two or more.

The ultraviolet absorber is preferably blended in an amount of 0.2 to 2 parts by weight based on 100 parts by weight of polyvinyl chloride. When the blending amount of the UV absorber is less than 0.2 parts by weight, the UV absorption amount becomes insufficient and the weather resistance may not be sufficiently increased. When there are more compounding quantities of a ultraviolet absorber than 2 weight part, a ultraviolet absorber may transfer to the surface of the base material 2, and may eject.

(Plasticizer)
Examples of the plasticizer include high molecular weight polyester plasticizers; phthalic plasticizers such as octyl phthalate (di-2-ethylhexyl phthalate), dibutyl phthalate, dinonyl phthalate, diisononyl phthalate; dioctyl adipate, sebacine Aliphatic dibasic acid plasticizers such as dioctyl acid; and phosphoric acid plasticizers such as tricresyl phosphate and trioctyl phosphate. These plasticizers may be used alone or in combination of two or more.

Examples of the high molecular polyester plasticizer include polyalkylene glycol diesters such as polyethylene glycol diester, polypropylene glycol diester, and polyethylene glycol polypropylene glycol diester of phthalic acid; aliphatic dibasic acids such as adipic acid and sebacic acid, polyethylene And polyalkylene glycol diesters such as glycol diester, polypropylene glycol diester, and polyethylene glycol polypropylene glycol diester. These high molecular polyester plasticizers may be used alone or in combination of two or more.

The number average molecular weight of the plasticizer is preferably 350 to 5000. When the number average molecular weight of the plasticizer is smaller than 350, the plasticizer may move to the surface of the substrate 2 and be ejected. When the number average molecular weight of the plasticizer is larger than 5000, sufficient plasticity may not be imparted by the plasticizer, and the processability of the substrate 2 may deteriorate.

The plasticizer is preferably blended in an amount of 10 to 50 parts by weight based on 100 parts by weight of polyvinyl chloride. When the blending amount of the plasticizer is less than 10 parts by weight, sufficient plasticity may not be imparted by the plasticizer, and the workability of the substrate 2 may be lowered. When the blending amount of the plasticizer is more than 50 parts by weight, the plasticizer may move to the surface of the substrate 2 and be ejected.

The base material 2 may further contain additives such as a colorant, a foaming agent, a lubricant, a modifier, a filler, and a diluent. As these additives, those generally blended with polyvinyl chloride can be used.

The thickness of the substrate 2 is preferably 50 to 120 μm. When the thickness of the base material 2 is smaller than 50 μm, the flexibility of the base material 2 becomes too high, and the workability may be lowered. When the thickness of the base material 2 is larger than 120 μm, the flexibility of the base material 2 becomes too low, and the workability may be lowered.

Printing may be performed on the surface of the substrate 2 opposite to the primer layer 3. Thereby, the designability of the film 1 for marking increases. Examples of the printing method on the substrate 2 include a thermal transfer printing method. The thermal transfer printing on the base material 2 can be performed by using, for example, a thermal transfer type label printer. Since the base material 2 is a soft polyvinyl chloride film, the thermal transfer printing becomes easy.

The surface of the substrate 2 opposite to the primer layer 3 may be subjected to surface processing such as embossing. When the embossing is performed on the surface of the substrate 2 opposite to the primer layer 3 to give an embossed shape (uneven shape), the embossed shape improves the texture. Will increase.

<Primer layer>
The primer layer 3 contains an acrylic resin having a primary amino group.

According to the primer layer 3, adhesion between the base material 2 and the pressure-sensitive adhesive layer 4 is increased. Furthermore, since the primer layer 3 contains an acrylic resin having a primary amino group, migration of the plasticizer in the substrate 2 to the pressure-sensitive adhesive layer 4 is prevented. As a result, even if it is used outdoors for a long time, the adhesive force of the marking film 1 is hardly reduced.

(Acrylic resin having primary amino group)
Examples of the acrylic resin having a primary amino group include aminoethylated acrylic polymers.

When forming the primer layer 3, the usage-amount (application amount) of the acrylic resin which has a primary amino group becomes like this. Preferably it is 2-12 g / m.

<Adhesive layer>
The pressure-sensitive adhesive layer 4 contains an acrylic pressure-sensitive adhesive and an isocyanate curing agent.

According to the pressure-sensitive adhesive layer 4, the marking film 1 can be easily attached. In addition, acrylic pressure-sensitive adhesives are excellent in tackiness, processability, heat aging resistance, moisture aging resistance, and weather resistance, and the cross-linking reaction is promoted by combining with an isocyanate curing agent, resulting in In particular, the adhesive strength is remarkably increased.

(Acrylic adhesive)
The acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive containing an acrylic polymer. Examples of the acrylic pressure-sensitive adhesive include a homopolymer of (meth) acrylic acid alkyl ester, a copolymer of (meth) acrylic acid alkyl ester and another monomer, and the like.

(Isocyanate curing agent)
Examples of the isocyanate curing agent include tolylene diisocyanate and hexamethylene diisocyanate.

The isocyanate-based curing agent is blended in an amount of 0.4 parts by weight or less and preferably 0.05 to 0.4 parts by weight with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive. When the compounding amount of the isocyanate curing agent is more than 0.4 parts by weight, the cohesive force of the acrylic pressure-sensitive adhesive is lowered, and as a result, the pressure-sensitive adhesive force is lowered. On the other hand, when the amount of the isocyanate curing agent is too small, for example, less than 0.05 parts by weight, the crosslinking reaction with the acrylic pressure-sensitive adhesive becomes insufficient, and the adhesive strength may be lowered. Here, the blending amounts of the acrylic pressure-sensitive adhesive and the isocyanate curing agent described above refer to blending amounts excluding these dilution solvents.

The thickness of the pressure-sensitive adhesive layer 4 is preferably 10 to 60 μm, more preferably 10 to 40 μm. When the thickness of the pressure-sensitive adhesive layer 4 is smaller than 10 μm, sufficient adhesive strength may not be obtained. When the thickness of the pressure-sensitive adhesive layer 4 is larger than 60 μm, the flexibility of the pressure-sensitive adhesive layer 4 becomes too low, and the workability may be lowered.

The marking film 1 may further have a separator on the surface of the pressure-sensitive adhesive layer 4 opposite to the primer layer 3. This prevents the pressure-sensitive adhesive layer 4 from being exposed during the production, transportation, and storage of the marking film 1, thereby preventing the pressure-sensitive adhesive layer 4 from being deteriorated and improving the handleability of the marking film 1. The separator may be peeled off immediately before the marking film 1 is attached.

As a separator, what is normally used in the field | area of a film can be used, For example, a release film, a release paper, etc. are mentioned.

As a release film, for example, a release treatment by applying a silicon release agent, an alkyd release agent, a fluorine release agent or the like on the surface of the resin film such as a polyethylene terephthalate film that is attached to the adhesive layer 4 Is given.

As the release paper, for example, the surface of the high-quality paper that is attached to the pressure-sensitive adhesive layer 4 is subjected to release treatment by application of a silicon release agent, an alkyd release agent, a fluorine release agent, or the like. Can be mentioned.

As described above, according to the marking film 1, a marking film having high initial adhesive strength, high adhesive strength even when used outdoors for a long time, and excellent weather resistance is realized.

The marking film 1 only needs to be used for marking purposes. For example, the marking film 1 may be attached to a factory pipe (for example, a pipe or cable), a utility pole, or the like. Since the marking film 1 is excellent in weather resistance, it is effectively used particularly outdoors. Further, the marking film 1 can be attached at room temperature or while being heated.

The marking film 1 can be manufactured, for example, by the following method.

First, an epoxy stabilizer, an ultraviolet absorber, a plasticizer, and the like are blended with polyvinyl chloride to prepare a polyvinyl chloride composition. And after melt-kneading the obtained polyvinyl chloride-type composition with apparatuses, such as a Banbury mixer, a kneader, and an extruder, the base material 2 is formed by shaping | molding methods, such as calendar molding, extrusion molding, and injection molding. Examples of the calendar format used at the time of calendar molding include an inverted L shape, a Z shape, an upright two shape, an L shape, and an inclined three shape.

Next, the primer layer 3 is formed on the surface of the base material 2 by applying an acrylic resin having a primary amino group on the surface of the base material 2 and drying it.

Next, an isocyanate-based curing agent is blended with the acrylic pressure-sensitive adhesive to prepare an acrylic pressure-sensitive adhesive composition. And the adhesive layer 4 is once formed on the surface of a separator by apply | coating the obtained acrylic adhesive composition on the surface of a separator, and making it dry. Thereafter, the pressure-sensitive adhesive layer 4 is formed (transferred) on the surface of the primer layer 3 opposite to the substrate 2 by attaching the separator to the primer layer 3 from the pressure-sensitive adhesive layer 4 side. As a result, the marking film 1 is obtained. In addition, what is necessary is just to peel a separator when sticking the film 1 for marking. Moreover, when forming the adhesive layer 4, you may apply | coat an acrylic adhesive composition on the surface on the opposite side to the base material 2 of the primer layer 3, and may make it dry.

EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail about this invention, this invention is not limited only to these Examples.

Example 1
First, with respect to 100 parts by weight of polyvinyl chloride, 3 parts by weight of an epoxy stabilizer (“Marproof (registered trademark) G-0150M” manufactured by NOF Corporation: solid (powder) at room temperature) and benzophenone 1 part by weight of an ultraviolet absorber (“ADEKA STAB (registered trademark) 1413” manufactured by ADEKA) and 20 parts by weight of a polymer polyester plasticizer (“PN-7230” manufactured by ADEKA) A vinyl chloride composition was prepared. And after melt-kneading the obtained polyvinyl chloride type composition with a Banbury mixer, the base material was formed by performing calendar molding. The thickness of the base material was 80 μm.

Next, an acrylic resin having a primary amino group ("Polyment (registered trademark) NK-380" manufactured by Nippon Shokubai Co., Ltd.) is applied on the surface of the base material and dried to thereby form the primer layer on the surface of the base material Formed on top.

Next, with respect to 100 parts by weight of an acrylic pressure-sensitive adhesive (“SK Dyne (registered trademark) 1502C” manufactured by Soken Chemical Co., Ltd.) diluted with a diluent solvent (solid content concentration: 39% by weight), an isocyanate-based curing agent An acrylic pressure-sensitive adhesive composition was prepared by blending 0.1 part by weight (solid concentration: 46% by weight) of “L-45” (manufactured by Soken Chemical Co., Ltd.) diluted with a diluent solvent. In the obtained acrylic pressure-sensitive adhesive composition, the isocyanate-based curing agent (solid content) was 0.12 parts by weight with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive (solid content). And the adhesive layer obtained was once formed on the surface of the separator by apply | coating the obtained acrylic adhesive composition on the surface of a separator, and making it dry. Thereafter, the pressure-sensitive adhesive layer was formed (transferred) on the surface of the primer layer opposite to the base material by attaching the separator to the primer layer from the pressure-sensitive adhesive layer side. The thickness of the pressure-sensitive adhesive layer was 25 μm. As a result, the marking film of Example 1 was obtained.

(Examples 2 to 4 and Comparative Examples 1 to 4)
A marking film of each example was manufactured in the same manner as in Example 1 except that the specifications of the base material, the primer layer, and the pressure-sensitive adhesive layer were changed as shown in Tables 1 and 2. In addition, the epoxy-type stabilizer mix | blended in the comparative examples 2 and 4 was the epoxidized soybean oil "ADEKA SIZER (trademark) O-130P" (liquid state at normal temperature) by ADEKA. In Examples 2 to 4 and Comparative Examples 1 to 3, the blending amounts (solid blending amounts) of the acrylic pressure-sensitive adhesive and the isocyanate curing agent are as shown in Tables 1 and 2. In addition, an acrylic adhesive diluted with a diluent solvent (solid content concentration: 39% by weight) and an isocyanate curing agent diluted with a diluent solvent (solid content concentration: 46% by weight) are mixed at a predetermined ratio. Then, an acrylic pressure-sensitive adhesive composition was prepared. In Tables 1 and 2, the types of acrylic adhesives A, B, and C are as follows.
A: “SK Dyne 1502C” manufactured by Soken Chemical Co., Ltd.
B: “Olivein (registered trademark) BPS5762K” manufactured by Toyochem
C: “Acryset (registered trademark) AST-8155” manufactured by Nippon Shokubai Co., Ltd.

[Evaluation]
The following evaluation was performed about the marking film of each example. The results are shown in Tables 1 and 2.

(Adhesive)
First, the marking film was cut to prepare a test piece having a length of 150 mm and a width of 25 mm (in a state where the separator was peeled off). Next, the obtained test piece is attached to a test plate made of stainless steel (SUS) and a test plate made of polypropylene (PP) resin, and left in an environment at a temperature of 80 ° C. for 7 days. The adhesive strength before and after was measured. The measurement of adhesive force was performed by the method (180 degree peeling test) based on JIS Z0237 "Test method of an adhesive tape and an adhesive sheet". And the adhesive force retention was computed by following formula (X).
“Adhesive strength retention (%)” = 100 × “Adhesive strength after high-temperature storage test (N / 25 mm)” / “Adhesive power before high-temperature storage test (N / 25 mm)” (X)

(Weatherability)
First, the base material simple substance which comprises the film for marking was cut | judged, and the test piece of length 30mm and width 30mm was produced. Next, the accelerated weathering test which exposes to the obtained test piece for 96 hours using the metal halide weathering tester (made by Suga Test Instruments Co., Ltd.) was performed on condition of the following.
Light source: Metal halide irradiance: 1.2 kW / m ² (wavelength: 300 to 400 nm)
Black panel temperature (BPT): 53 ° C
Humidity in the tank: 40%
Test cycle: Irradiation 20 hours → dark + condensation 4 hours (within 20 hours of irradiation, shower (rain) is carried out every 15 minutes for 10 seconds)
And the color difference ((DELTA) E) before and behind an accelerated weathering test was measured. Here, the smaller the color difference, the higher the weather resistance.

In Examples 1 to 4, the adhesive strength and adhesive strength retention before and after the high-temperature standing test were high, and the weather resistance was high (no significant discoloration was observed). That is, according to Examples 1 to 4, a marking film having high initial adhesive strength, high adhesive strength even when used outdoors for a long time, and excellent weather resistance was realized.

In Comparative Example 1, since the primer layer was not provided, the adhesive strength was greatly reduced after the high temperature storage test, and the adhesive strength retention was low.

In Comparative Example 2, the primer layer was not provided, and in the pressure-sensitive adhesive layer, the amount of the isocyanate-based curing agent was significantly larger than 0.4 parts by weight with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive. The adhesive strength before and after the standing test, particularly the adhesive strength after the high temperature standing test was very low, and the adhesive strength retention was very low.

In Comparative Example 3, the primer layer was not provided, and in the pressure-sensitive adhesive layer, the amount of the isocyanate curing agent was more than 0.4 parts by weight with respect to 100 parts by weight of the acrylic pressure-sensitive adhesive. The adhesive strength before and after was low.

In Comparative Example 4, the base material alone (state in which neither the primer layer nor the pressure-sensitive adhesive layer was provided) was evaluated, but the weather resistance was very low because no ultraviolet absorber was blended.

1: Marking film 2: Base material 3: Primer layer 4: Adhesive layer

Claims (3)

A base material in which an epoxy stabilizer, an ultraviolet absorber and a plasticizer are blended with polyvinyl chloride;
A primer layer containing an acrylic resin having a primary amino group;
A pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive and an isocyanate curing agent, and in order,
The marking film, wherein the isocyanate curing agent is blended in an amount of 0.4 parts by weight or less based on 100 parts by weight of the acrylic pressure-sensitive adhesive. The marking film according to claim 1, wherein the ultraviolet absorber is a benzophenone ultraviolet absorber or a benzotriazole ultraviolet absorber. The marking film according to claim 1 or 2, wherein the ultraviolet absorber is blended in an amount of 0.2 to 2 parts by weight with respect to 100 parts by weight of the polyvinyl chloride.

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