JP2003183604A - Removable adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a removable adhesive film capable of attaching to a polystyrene-based adherend, not requiring release of the adherend when the adherend is used for regeneration and readily releasing the film when the film is reutilized. <P>SOLUTION: This removable adhesive film is obtained by laminating an adhesive layer and a releasable sheet on a polystyrene-based film base. In the adhesive film, adhesive force with time to the polystyrene-based adherend is 2.0 to 4.0 N/25 mm at 5 mm/min release rate and 8.0 to 12.0 N/25 mm at 300 mm/min release rate. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive film which can be attached to a polystyrene-based adherend and has excellent removability. More specifically, the present invention relates to a removable pressure-sensitive adhesive film that does not need to be peeled off when reusing a polystyrene-based adherend and can be easily peeled off when reusing it.

[0002]

2. Description of the Related Art A polystyrene-based adherend formed by molding a polystyrene-based resin such as polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), or modified polyphenylene ether (modified PPE) is a casing for OA equipment and home electric appliances. It is used as a body. Generally, a label for displaying a caution or a warning is attached to the housing. The label is produced by printing an adhesive film which is a raw material for the label. In recent years, in order to recycle these casings, it has been known to use a polystyrene film of the same material as the casing as a base material of an adhesive film which is a label raw material. In this case, the casing can be easily recycled by crushing, melting, pelletizing, and re-molding the label without removing it from the casing. Specific examples thereof are described in JP-A-9-13256 and JP-A-10-105063. On the other hand, recently, attention has been paid to reusing a housing after reuse, rather than recycling. That is, after the housing is used, the label is peeled off and reused, and when the housing is no longer resistant to reuse after being reused several times, the label is recycled without being peeled off. However, when the conventional label is peeled off from the housing, the adhesive of the label remains on the polystyrene-based adherend of the housing and contaminates the adherend. In addition, the polystyrene film as the base material is torn and the work efficiency of peeling is reduced. However, in view of the above, when the adhesive force of the pressure-sensitive adhesive layer is reduced and the label is easily peeled off,
There is a problem that it falls off from the polystyrene-based adherend.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the problems of a pressure-sensitive adhesive film obtained by laminating a polystyrene-based film substrate, a pressure-sensitive adhesive layer and a release sheet, which are attached to a polystyrene-based adherend, It is an object of the present invention to provide a removable pressure-sensitive adhesive film that does not need to be peeled when reusing an adhered body and can be easily peeled when reusing.

[0004]

Means for Solving the Problems As a result of earnest research, the present inventors have found that the problems can be solved by using the following adhesive film. That is, the removable pressure-sensitive adhesive film of the present invention is a pressure-sensitive adhesive film obtained by laminating a polystyrene-based film substrate, a pressure-sensitive adhesive layer and a release sheet,
Adhesion with time to polystyrene adherend has a peeling speed of 5
The releasable pressure-sensitive adhesive film is characterized in that it has a peeling speed of 2.0 to 4.0 N / 25 mm and a peeling speed of 300 mm / min and is 8.0 to 12.0 N / 25 mm.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The removable pressure-sensitive adhesive film according to the present invention will be specifically described below. The removable pressure-sensitive adhesive film of the present invention has a time-dependent adhesive strength (that is, a temperature of 60 ° C., a humidity of 90% RH, a peel adhesive strength after a lapse of 3 days) to a polystyrene adherend of 2.0 to 2.0 at a peeling speed of 5 mm / min.
It is controlled to be in the range of 4.0 N / 25 mm and 8.0-12.0 N / 25 mm at a peeling speed of 300 mm / min. If the adhesive strength over time is less than this range, the removable pressure-sensitive adhesive film is pushed up by the gas generated from the inside of the polystyrene-based adherend after sticking, and floating occurs at one end thereof. On the other hand, if the adhesive strength over time exceeds this range, the adhesive may remain on the polystyrene-based adherend during peeling, or the polystyrene-based film of the substrate may break. here,
The time-dependent adhesive force at a low peeling speed of 5 mm / min is mainly related to the likelihood of floating of the removable peelable adhesive film from the polystyrene-based adherend during sticking. In addition, the adhesive strength with time at a high speed of 300 mm / min mainly relates to the ease of peeling off the removable pressure-sensitive adhesive film when the polystyrene-based adherend is recycled. The measuring method of the adhesive strength with time is as follows. 23 mm wide removable adhesive film
It is attached to a polystyrene adherend at a temperature of 65 ° C. and a humidity of 65% RH and left at 60 ° C. and a humidity of 90% RH for 3 days. next,
The measurement is performed by peeling the substrate at 23 ° C. and a humidity of 65% RH at an angle of 180 degrees at each peeling speed.

[0006] As an adhesive that satisfies such conditions,
An example is one in which a cross-linking agent is added to an adhesive main agent that does not contain a tackifying resin.

As the adhesive main agent, a known (meth) acrylic acid ester copolymer obtained by copolymerizing an adhesive monomer, an aggregating monomer, and a monomer having a functional group capable of reacting with a crosslinking agent is suitable for removability. There is. Examples of the adhesive monomer include (meth) acrylic acid esters having an alkyl group having 1 to 12 carbon atoms, such as ethyl acrylate, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, and n-nonyl acrylate. . The content of at least one of these is preferably 50 to 95 mass% with respect to the total amount of monomers. More preferably 6
It is 5 to 95 mass%. Particularly suitable monomers are n-butyl acrylate and 2-ethylhexyl acrylate.

Examples of the aggregating monomer include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic anhydride. Also,
Examples of the aggregating monomer other than α, β-unsaturated carboxylic acid include vinyl acetate, acrylonitrile, styrene, methyl (meth) acrylate and the like. The amount of at least one of these is preferably 0 to 15 mass% with respect to the total amount of monomers. More preferably, it is 0 to 15 mass%. Particularly suitable monomers are acrylic acid, methacrylic acid, vinyl acetate, methyl methacrylate, acrylonitrile.

Examples of the monomer having a functional group which reacts with the crosslinking agent include a hydroxyl group-containing monomer such as 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl acrylate and 2-hydroxypropyl (meth) acrylate. Examples of the amino group-containing monomer include acrylamide and N-methylol acrylamide. Furthermore, examples of the glycidyl group-containing monomer include glycidyl methacrylate. The amount of at least one of these is preferably 0 to 5 mass% with respect to the total amount of monomers. More preferably, it is 0 to 5 mass%. A particularly suitable monomer is 2-hydroxyethyl (meth) acrylate.

The amount of the monomer compounded is set so that the glass transition point temperature of the adhesive main agent produced by copolymerizing the monomers is -70 to -40 ° C. The adhesive main agent is manufactured by radically polymerizing each monomer in an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, and ketones such as methyl ethyl ketone and cyclohexanone. Examples of the polymerization catalyst used include azobisisobutyronitrile (AIBN) and benzoyl peroxide.

Generally, a rosin resin for improving the adhesive strength,
Tackifying resins such as terpene resins, petroleum resins, styrene resins, and xylene resins may be blended. However, in the present invention, when the pressure-sensitive adhesive film is peeled off, the pressure-sensitive adhesive will remain on the polystyrene-based adherend, and thus is not blended.

A cross-linking agent is added to the above-mentioned pressure-sensitive adhesive main agent in order to improve cohesive force and anchoring with the substrate. Examples of the cross-linking agent include isocyanate type, metal chelate, epoxy type, and melamine type. Particularly preferred is an isocyanate type, more preferably a polyfunctional isocyanate, for example, a trimethylolpropane adduct of tolylene diisocyanate. The amount of the crosslinking agent used is not particularly limited. However, if the addition amount of the cross-linking agent is small, the cross-linking is insufficient, which causes an increase in the adhesive strength and a residual adhesive when re-peeling. Further, if the addition amount is large, crosslinking becomes excessive, which causes floating of the adhesive film. Therefore, the addition amount of the cross-linking agent is 0.2 to 5.0 parts by mass with respect to 100 parts by mass of the adhesive main agent. More preferably, it is 0.5 to 2.0 parts by mass.

The amount of the adhesive applied is 10 to 30 on a dry weight basis.
A range of g / m ² is preferred. If it is less than 10 g / m ² , sufficient adhesive strength cannot be obtained, and if it exceeds 30 g / m ² , it causes the sticking out of the adhesive during printing.

The method of applying the pressure-sensitive adhesive is as follows.
For example, a solid content of 20-
A coating liquid of 60 mass% is prepared. A release sheet such as polyethylene laminated paper, Krasin paper,
It is applied to a sheet in which a release agent of a silicone compound is applied to clay-coated paper, polyester film, polypropylene film and the like. After drying, it is attached to a polystyrene film substrate, the adhesive is transferred to the substrate and wound up. On the other hand, if the polystyrene film substrate is directly coated with the coating liquid, this coating method cannot be adopted because the substrate is dissolved by ethyl acetate or toluene in the coating liquid.

Examples of the coating device for the pressure-sensitive adhesive include known coating devices such as a knife coater, a comma coater, a gravure coater and a roll coater. A comma coater is particularly preferable.

The tensile strength at break of the polystyrene film substrate of the present invention is preferably 20 MPa or more in the MD direction and 15 MPa or more in the TD direction at a tensile speed of 200 mm / min. Here, the MD direction means the flow direction of the film, and the TD direction means the width direction of the film. MD
If it is less than 20 MPa in the direction and less than 15 MPa in the TD direction, the polystyrene film of the base material may not be able to withstand the adhesive force and may be cut when peeled from the polystyrene adherend.

The elongation at break of the polystyrene film base material of the present invention is 200 mm / min at a pulling speed, and the MD direction and T
It is preferably 30 to 60% in both D directions. 30%
If it is less than 100%, it may cause paper breakage during adhesive processing, and may cause film breakage during scraping during printing processing as described above, and the adhesive strength of the polystyrene film as the base material when peeling from the polystyrene adherend. It will not be able to endure and it will cause cutting. If it exceeds 60%, the rigidity (waist) is reduced and the workability of sticking the label is deteriorated. Further, when the label is peeled off, the film stretches, which causes a deterioration in peeling workability.

The methods for measuring the tensile strength at break and the elongation at break are as follows. Width 10 mm, marked line length 100 mm
The polystyrene-based film substrate punched out in the dumbbell shape of No. 2 was used for 200 at 23 ° C. and a humidity of 65% RH in a MD and TD direction using a Tensilon type tensile tester.
The value at break was measured by pulling at a speed of mm / min.

The polystyrene resin of the polystyrene film substrate of the present invention includes polystyrene resin (GPP).
S resin), impact-resistant polystyrene resin (HIPS resin) obtained by graft-polymerizing styrene to rubber, and GPPS
Impact polystyrene resin (MIPS resin) blended with HIPS and styrene / acrylonitrile copolymer (AS resin), styrene / methyl methacrylate copolymer resin, styrene / butadiene / acrylonitrile copolymer resin (ABS resin) ), Modified polyphenylene ether resin obtained by alloying GPPS with polyphenylene ether (modified PPE resin), and the like. A flexible HIPS resin or MIPS resin is preferable.
More preferably, it is a HIPS resin.

The rubber in HIPS is a component that imparts flexibility to the film, and synthetic rubber such as styrene-butadiene rubber (SBR) or polybutadiene rubber is preferably used as the rubber. SBR is more preferred. The copolymerization ratio of SBR is preferably 30 to 50% by mass, more preferably 35 to 45% by mass. If it is less than 30% by mass, the flexibility of the film is insufficient and the film is easily broken. If it exceeds 50%, the film becomes too soft and the workability of attaching and peeling the label deteriorates and the weather resistance becomes poor.

When coloring the film, a colorant (masterbatch) prepared by kneading titanium oxide with a HIPS resin can be added. HI added as film base
The masterbatch containing 50% by mass of titanium oxide is preferably 5 to 20 parts by mass, more preferably 10 to 15 parts by mass, relative to 100 parts by mass of the PS resin. If it is less than 5 parts by mass, the hiding property of the film will be poor. If it is 20 parts by mass or more, the film is likely to be torn, and foreign matters such as fish eyes are likely to occur on the film.

The method for forming a polystyrene-based film substrate includes a biaxial stretching method and a non-stretching method, but the non-stretching method in which shrinkage of the film due to heat is smaller is preferable. In addition, it is preferable to perform corona discharge treatment on both surfaces of the film in order to improve anchoring of printing ink and adhesive.

As described above, in order to improve the ink adhesion to the polystyrene film base material, it is preferable to perform corona discharge treatment. However, since the effect of improving the ink adhesion decreases with corona discharge treatment,
It is more preferable to provide an anchor coat layer having no attenuation. The anchor coat layer is formed by applying a coating agent comprising an ink-adsorbing pigment, a binder resin and a dispersion medium on one surface of the film. As the pigment, known calcium carbonate, titanium oxide, synthetic silica and the like can be used. Synthetic silica is more preferred. As the binder resin, acrylic resin, polyvinyl alcohol resin, ethylene / vinyl acetate copolymer resin, ethylene / vinyl alcohol copolymer resin, styrene / butadiene copolymer resin and the like can be used. Acrylic resin is preferable from the viewpoint of durability. The dispersion medium is selected so that it does not dissolve the HIPS of the base film. Basically, it is mainly composed of alcohol such as isopropyl alcohol and ethanol.
The content of the anchor coating agent is preferably 5 to 10 parts by mass of the pigment, 20 to 30 parts by mass of the binder resin, and 60 to 70 parts by mass of the dispersion medium. The coating amount of the coating agent is 0.5 to 4.0 g /
m ² is preferable, and more preferably 2.0 to 3.0 g / m ^2.
Is.

A knife coater, a gravure coater, a roll coater or the like can be used as a method for applying the anchor coat agent to the polystyrene film substrate. A gravure coater is particularly preferable.

The thickness of the polystyrene film substrate of the present invention is preferably 50 to 120 μm. 50μ
If it is less than m, wrinkles and entrapment of air bubbles are likely to occur when the removable pressure-sensitive adhesive film is attached to the polystyrene-based adherend. In addition, the scrap portion is easily cut during so-called scrap lifting to remove unnecessary portions during printing. On the other hand, when it exceeds 120 μm, when the pressure-sensitive adhesive film on which the release sheet and the pressure-sensitive adhesive are laminated is wound up, floating easily occurs between the pressure-sensitive adhesive and the release sheet.

Thus, the removable pressure-sensitive adhesive film of the present invention can be obtained. Such a removable pressure-sensitive adhesive film can be attached to a polystyrene-based adherend and need not be peeled off when the adherend is reused. On the other hand, it can be easily peeled off for reuse.

[0027]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In the examples, "parts" and "%" are based on mass unless otherwise specified.

(1) Synthesis of Adhesive Main Agent [Adhesive Main Agent (A)] In a reaction vessel equipped with a stirrer, cold flow cooler, thermometer, dropping funnel and nitrogen gas inlet,
59 parts of ethylhexyl acrylate, 32.6 parts of n-butyl acrylate, 5 parts of vinyl acetate, 3 parts of acrylic acid,
0.4 parts of 2-hydroxyethyl acrylate and 0.2 of azobisisobutyronitrile (AIBN) as a polymerization catalyst
Parts and 100 parts of ethyl acetate were charged, polymerized at 80 ° C. for 8 hours, and then diluted with toluene to obtain an adhesive main agent A having a glass transition temperature of −58 ° C. and a solid content of 40%. [Adhesive main agent (B)] In a reaction vessel equipped with a stirrer, a cold flow cooler, a thermometer, a dropping funnel and a nitrogen gas inlet,
85 parts of ethylhexyl acrylate, 14 parts of methyl acrylate, 0.9 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate, 0.2 parts of azobisisobutyronitrile (AIBN) as a polymerization catalyst and 1 part of ethyl acetate.
00 parts were charged, the mixture was polymerized at 80 ° C. for 8 hours, diluted with toluene, and the solid content 3 having a glass transition temperature of −61 ° C.
0% of the adhesive main agent B was obtained. [Adhesive main agent (C)] In a reaction vessel equipped with a stirrer, a cold flow cooler, a thermometer, a dropping funnel and a nitrogen gas inlet, n-
Butyl acrylate 92.9 parts, vinyl acetate 5 parts, acrylic acid 2 parts, 2-hydroxyethyl acrylate 0.1
Part and azobisisobutyronitrile (AI) as a polymerization catalyst
BN) 0.2 part and ethyl acetate 100 parts,
After being polymerized at 80 ° C. for 8 hours, it was diluted with toluene, and a pressure-sensitive adhesive main agent C having a glass transition temperature of −65 ° C. and a solid content of 45%.
Got

(2) Preparation of Adhesive [Adhesive (a-1)] 100 parts by mass of the above-mentioned adhesive main agent (A) was added to an isocyanate crosslinking agent ("Coronate L-55" manufactured by Nippon Polyurethane Industry Co., Ltd.). 8 parts was added and stirred for 15 minutes to obtain an adhesive (a-1). [Adhesive (a-2)] In the adhesive (A-1), an adhesive (a-2) was obtained under the same conditions except that the amount of the isocyanate crosslinking agent added was 0.8 parts to 1.0 part. It was [Adhesive (a-3)] In the adhesive (A-1), an adhesive (a-3) was obtained under the same conditions, except that the addition amount of the isocyanate crosslinking agent was 0.8 part. It was [Adhesive (a-4)] Adhesive (a-) under the same conditions except that 30 parts of rosin-based tackifying resin ("Pentaline CJ" manufactured by Rika Hercules Co., Ltd.) was added to the adhesive (A-1). 4) was obtained. [Adhesive (b-1)] 0.2 part of an isocyanate cross-linking agent ("Coronate L-55" manufactured by Nippon Polyurethane Industry Co., Ltd.) was added to 100 parts by mass of the above-mentioned adhesive main agent (B) and stirred for 15 minutes. , And an adhesive (b-1) was obtained. [Adhesive (c-1)] 1.2 parts of an isocyanate crosslinking agent (“Coronate L-55” manufactured by Nippon Polyurethane Industry Co., Ltd.) and 100 parts by weight of the above-mentioned adhesive main agent (C) and a rosin-based tackifying resin (Rika) Hercules "Pentaline C"
J ”) is added and stirred for 15 minutes to prepare an adhesive (c-
1) was obtained.

(3) Production of polystyrene film substrate [polystyrene film substrate (I)] Styrene and SB
HI graft-polymerized with R of 60 parts and 40 parts respectively
A blend obtained by adding 15 parts of a masterbatch containing 50% titanium oxide to 100 parts of PS resin was melt extruded at 200 ° C. using an inflation film forming machine to obtain an unstretched film having a thickness of 70 μm. . Then, both sides of the film were subjected to corona discharge treatment. Further, an acrylic coating agent (“SF Primer SRK # 6 Matt” manufactured by Dainippon Ink and Chemicals, Inc.) was applied to one side of the film subjected to double-sided corona discharge treatment by using a gravure coater to obtain a coating amount of 2.
An anchor coat layer of 5 g / m ² was provided to obtain a polystyrene film base material (I). [Polystyrene film substrate (II)] A polystyrene film substrate (II) was obtained under the same conditions as the polystyrene film substrate (I) except that the thickness of the unstretched film was 100 µm. [Polystyrene film substrate (III)] A polystyrene film substrate (III) was obtained under the same conditions as the polystyrene film substrate (I) except that the thickness of the unstretched film was 30 µm. [Polystyrene film substrate (IV)] A polystyrene film substrate (IV) was obtained under the same conditions as the polystyrene film substrate (I) except that the thickness of the unstretched film was 150 µm. [Polystyrene film substrate (V)] The polystyrene film substrate (V) was prepared under the same conditions except that the polymerization ratios of styrene and SBR were 55 parts and 45 parts, respectively, in the polystyrene film substrate (II). ) Got. [Polystyrene film substrate (VI)] The polystyrene film substrate (VI) was prepared under the same conditions except that the polymerization ratio of styrene and SBR was 50 parts and 50 parts, respectively. ) Got. [Polystyrene film substrate (VII)] In the polystyrene film substrate (II), styrene and SBR
A polystyrene-based film substrate (VII) was obtained under the same conditions except that the polymerization ratios of and were set to 80 parts and 20 parts, respectively.

[Example 1] A pressure-sensitive adhesive (a-1) was applied to a release sheet ("OKB-105NC" manufactured by Oji Paper Co., Ltd.) in which polyethylene compound paper was coated with a silicone compound, and the release sheet was applied at 80 ° C for 90 seconds. Dry to dry weight 20g / m ²
The pressure-sensitive adhesive layer of 1 was formed and bonded to the polystyrene film substrate (I) to obtain a pressure-sensitive adhesive sheet.

Example 2 An adhesive sheet was obtained under the same conditions as in Example 1 except that the polystyrene film substrate (II) was used as the polystyrene film substrate.

[Example 3] As an adhesive, an adhesive (a-
An adhesive sheet was obtained under the same conditions as in Example 2 except that 2) was used.

Example 4 An adhesive sheet was obtained under the same conditions as in Example 1 except that the polystyrene film substrate (V) was used as the polystyrene film substrate.

Comparative Example 5 An adhesive sheet was obtained under the same conditions as in Example 1 except that the polystyrene film substrate (III) was used as the polystyrene film substrate.

[Comparative Example 6] An adhesive sheet was obtained under the same conditions as in Example 1 except that the polystyrene film base material (IV) was used as the polystyrene film base material.

[Comparative Example 7] An adhesive sheet was obtained under the same conditions as in Example 1 except that the polystyrene film substrate (VI) was used as the polystyrene film substrate.

Comparative Example 8 An adhesive sheet was obtained under the same conditions as in Example 1 except that the polystyrene film substrate (VII) was used as the polystyrene film substrate.

[Comparative Example 1] As a pressure-sensitive adhesive, a pressure-sensitive adhesive (a-
An adhesive sheet was obtained under the same conditions as in Example 2 except that 3) was used.

[Comparative Example 2] As a pressure-sensitive adhesive, a pressure-sensitive adhesive (a-
An adhesive sheet was obtained under the same conditions as in Example 2 except that 4) was used.

[Comparative Example 3] As a pressure-sensitive adhesive, a pressure-sensitive adhesive (b-
An adhesive sheet was obtained under the same conditions as in Example 2 except that 1) was used.

[Comparative Example 4] An adhesive (c-
An adhesive sheet was obtained under the same conditions as in Example 2 except that 1) was used.

The evaluation method will be described below. <Adhesion with Time> A releasable pressure-sensitive adhesive film having a width of 25 mm and a length of 100 mm is attached to a polystyrene-based adherend at 23 ° C. and a humidity of 65% RH, and after reciprocating a pressure of 2 kg with a roller, the pressure is applied 8 times.
Leave for 3 days at 60 ° C. and humidity of 90% RH. Then 23
5m at a temperature of 180 ° under RH and 65% RH
Peeling was performed at a peeling speed of m / min and 300 mm / min, and the adhesive force with time was measured.

<Thickness> The thickness of the polystyrene film substrate was measured using a thickness meter.

<Tensile breaking strength and breaking elongation> Width 10 m
Using a Tensilon tensile tester in MD and TD, a polystyrene-based film substrate punched out in a dumbbell shape having a length of m and a marked line length of 100 mm was used at a speed of 200 mm / min at 23 ° C. and a humidity of 65% RH. And the value at break was measured.

<Attachability> A releasable adhesive film having a width of 25 mm and a length of 100 mm was attached to a polystyrene adherend at 23 ° C. and a humidity of 65% RH, and wrinkles were not formed on the releasable adhesive film at that time. The inclusion of bubbles was observed and evaluated according to the following criteria. Good: No wrinkles or air bubbles are observed. Δ: Wrinkles are slightly generated, but air bubbles are not involved. Can be used. X: Occurrence of wrinkles and inclusion of bubbles. Cannot be used.

<Floating resistance> 25 mm width × 100 mm length
The re-peelable pressure-sensitive adhesive film of is attached to a polystyrene-based adherend at 23 ° C. and a humidity of 65% RH, and a reciprocating pressure of 2 kg roller is applied 8 times. After leaving at 60 ° C and humidity 90% RH for 3 days,
The floating condition of the pressure-sensitive adhesive film was observed at 23 ° C. and a humidity of 65% RH and evaluated according to the following criteria. ○: No floating is observed. Δ: Lifting is recognized, but within 2 mm from the end x: Lifting of 2 mm or more is recognized from the end

<Removability> Width 25 mm x length 100 mm
The re-peelable pressure-sensitive adhesive film of is attached to a polystyrene-based adherend at 23 ° C. and a humidity of 65% RH, and a reciprocating pressure of 2 kg roller is applied 8 times. After leaving at 60 ° C and humidity 90% RH for 3 days,
The adhesive film was peeled off by hand at 23 ° C. and a humidity of 65% RH, and the cutting of the polystyrene-based film base material and the adhesive residue on the adherend at that time were observed and evaluated according to the following criteria. ⊚: No cutting of the base material and no residual adhesive were observed. ○: There was cutting or elongation of the base material, but no adhesive remained. Can be used. Δ: The base material was not cut or stretched, but some adhesive remained. Can be used. X: There is also cutting of the base material and residual adhesive. Cannot be used.

<Ability to Take Up> An adhesive is applied to a release sheet, dried, and then the adhesive sheet laminated with a polystyrene film substrate is taken up on a paper tube having an inner diameter of 25.4 mm. 1
The degree of floating between the pressure sensitive adhesive and the release sheet was observed from above the paper tube when it was wound up at 0 revolutions, and evaluated according to the following criteria. ◯: No floating is observed between the adhesive and the release sheet Δ: There is some floating between the adhesive and the release sheet. Can be used. X: There is floating between the adhesive and the release sheet. Cannot be used.

<Scraping Suitability> A long release sheet is coated with an adhesive and dried, and then laminated with a long polystyrene-based film substrate to prepare a long adhesive sheet. Then width 6
A long adhesive sheet is produced by cutting it to 0 mm. 50 mm wide, 50 m wide using a spiral blade from the surface of the polystyrene film substrate through the adhesive to just before the release sheet
Continuously punch in squares of m. The distance between one square and the next square is 10 mm. Roll up only the part of the adhesive sheet excluding the square (hereinafter referred to as "dust"). The cutting of the dust at that time was observed and evaluated according to the following criteria. ◯: No cutting was observed on the residue. B: Can be wound up although some of the residue is cut. Can be used. X: Scrap is cut. Cannot be used.

<Comprehensive Evaluation> The final judgment of use as a removable pressure-sensitive adhesive film is as follows. ◎: Most suitable for use ○: Suitable for use △: Some problems but can be used ×: Cannot be used

Table 1 shows the evaluation results of the examples and comparative examples.

[0053]

[Table 1]

[0054]

EFFECTS OF THE INVENTION The removable pressure-sensitive adhesive film of the present invention satisfies the adhesive strength that does not cause floating when adhered to a polystyrene-based adherend, suitability for winding up and suitability for scraping during labeling, Since it uses a base material of the same material as the body, it does not need to be peeled off when recycled, and it can be easily peeled off when reused, and it has the property that the adhesive does not remain easily. Can greatly contribute to

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the structure of a removable pressure-sensitive adhesive film of the present invention.

[Explanation of symbols]

1. Anchor coat layer 2. Polystyrene film substrate 3. Adhesive layer 4. Release sheet

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J004 AA09 AA10 AA17 AB01 AB04                       CA03 CC02 DB02                 4J040 DB061 DF011 DF021 DF041                       DF051 DF081 EB132 EC002                       EF212 EF262 JA09 JB09                       KA26 PA23 PA42

Claims (4)

[Claims] 1. A pressure-sensitive adhesive film obtained by laminating a polystyrene-based film substrate, a pressure-sensitive adhesive layer, and a release sheet, wherein the time-dependent adhesion to a polystyrene-based adherend is a peeling speed of 5 m.
2.0 to 4.0 N / 25 mm at m / min, and peeling speed 3
A releasable pressure-sensitive adhesive film, which is 8.0 to 12.0 N / 25 mm at 00 mm / min. 2. The tensile breaking strength of the polystyrene film base material is 20 mm / min at a tensile speed of 200 mm / min.
The removable pressure-sensitive adhesive film according to claim 1, which has a pressure of at least 15 MPa and a pressure of at least 15 MPa in the TD direction. 3. The elongation at break of the polystyrene-based film substrate at a tensile speed of 200 mm / min, MD direction and TD
The releasable pressure-sensitive adhesive film according to claim 1 or 2, which is 30 to 60% in both directions. 4. The removable pressure-sensitive adhesive film according to claim 1, 2 or 3, wherein the polystyrene film substrate has a thickness of 50 to 120 μm.