JP5572546B2 - Adhesive film - Google Patents

Description

The present invention relates to an adhesive film, and is suitable for, for example, a binding tape for binding an electric wire / cable such as an automobile wire harness by forming the adhesive film into a tape shape, and a marking film displaying characters and figures on the surface of the adhesive film. Can be used.

As various adhesive films such as insulating tape used for various electrical equipment in automobiles, railways, aircraft, ships, houses, factories, etc., it has moderate flexibility and extensibility, flame resistance, mechanical strength, An adhesive was applied to one side of a base material made from a resin composition containing a vinyl chloride resin, because of its excellent heat resistance, electrical insulation and moldability, and relatively low cost. Vinyl chloride adhesive film is used.

Generally, a softening agent is blended with the base material of the adhesive film in order to soften the base material. However, the softener sometimes moved from the base material to the pressure-sensitive adhesive layer with time. When the softener moves to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive softens and is squeezed out to the side of the rolled product, causing stickiness (side stick), and the pressure-sensitive adhesive cohesive force and pressure-sensitive adhesive force decrease. In some cases, the adhesive film peeled off the adherend. Further, when the adhesive film is peeled off, a part of the adhesive and the softening agent remain on the adherend, which may contaminate the adherend.

As an adhesive film that suppresses the migration of such a softener, an adhesive film in which a curable primer is provided between a soft substrate and an adhesive layer has been proposed (for example, Patent Document 1 and Patent Document 2). . However, these pressure-sensitive adhesive films are overlapped when wound in a roll shape unless the adhesive surface is protected with a base material separator or the back surface of the base material is not surface-treated. The surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film and the back surface of the other pressure-sensitive adhesive film are in direct contact with each other, and the softening agent moves between the pressure-sensitive adhesive films. Therefore, there is a problem that the movement of the softening agent cannot be sufficiently suppressed unless the glue surface and the back surface are further protected.

JP-A-11-263946 JP 2002-146274 A

An object of the present invention is to provide a pressure-sensitive adhesive film in which the softening agent is little transferred from the base material to the pressure-sensitive adhesive, has excellent pressure-sensitive adhesive force, unwinding force, and holding power and has little adhesive residue on the adherend.

The present invention achieves the above-mentioned object and has the following gist.
(1) A pressure-sensitive adhesive film comprising a base material comprising a vinyl chloride resin composition and a pressure-sensitive adhesive layer formed on at least one side of the base material, wherein the pressure-sensitive adhesive layer comprises (i) natural rubber and / Or an adhesive base agent comprising styrene-butadiene rubber,
(Ii) a graft polymer obtained by graft polymerizing a natural rubber and / or a styrene-butadiene rubber with a (meth) acrylic acid ester having an alkyl group, and (iii) a softening agent,
(A) The softener is blended in an amount of 0.3 to 4% by mass with respect to the adhesive constituting the adhesive layer.
(B) The graft polymer is blended in an amount of 10 to 50 parts by mass with respect to 100 parts by mass of the adhesive base agent made of natural rubber and / or styrene-butadiene rubber.
(C) An adhesive film in which the Mooney viscosity of the graft polymer is a Mooney viscosity of 60 to 90 Ms1 + 4 (100 ° C.) in accordance with JIS K 6300.
(2) The adhesive film according to (1), wherein the vinyl chloride resin composition contains 50% by mass or more of vinyl chloride resin with respect to the total amount of the resin component.
(3) The pressure-sensitive adhesive film according to (1), wherein the graft polymer is obtained by graft polymerization of 60 to 80% by mass of styrene-butadiene rubber and 20 to 40% by mass of (meth) acrylic acid ester having an alkyl group. .
(4) The above (1), wherein the (meth) acrylic acid ester having an alkyl group is selected from the group consisting of methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and a mixture thereof. The adhesive film as described in 2.
(5) The pressure-sensitive adhesive film according to (1), wherein the softening agent is diisononyl phthalate.
(6) The pressure-sensitive adhesive film according to (1), wherein the base material contains 15 to 45% by mass of a softening agent with respect to the total amount of resin components of the vinyl chloride resin composition.

ADVANTAGE OF THE INVENTION According to this invention, the transfer of the softening agent from a base material to an adhesive can be obtained, and the adhesive film which is excellent in adhesive force, unwinding force, and holding power, and has little adhesive residue to a to-be-adhered body can be obtained.

The pressure-sensitive adhesive film of the present invention is a pressure-sensitive adhesive film composed of a base material made of a vinyl chloride resin composition and a pressure-sensitive adhesive layer formed on at least one side of the base material, and the pressure-sensitive adhesive layer comprises: Contains 0.3 to 4% by mass of a softening agent based on the pressure-sensitive adhesive, and a graft polymer obtained by graft-polymerizing (meth) acrylic acid ester having an alkyl group to natural rubber and / or styrene-butadiene rubber. It is formed by the pressure sensitive adhesive.

<I. Base material>
The vinyl chloride resin composition constituting the substrate is not particularly limited as long as it contains a vinyl chloride resin as a main component of the resin component. The vinyl chloride resin is a homopolymer resin that is a conventionally known homopolymer of vinyl chloride or various conventionally known copolymer resins, and is not particularly limited.

As the copolymer resin, a conventionally known copolymer resin can be used. A copolymer resin of vinyl chloride and vinyl esters such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl propionate copolymer resin; vinyl chloride-butyl acrylate Copolymer resins, copolymer resins of vinyl chloride and acrylates such as vinyl chloride-2-ethylhexyl acrylate copolymer resin; copolymer resins of vinyl chloride and olefins such as vinyl chloride-ethylene copolymer resin, vinyl chloride-propylene copolymer resin Vinyl chloride-acrylonitrile copolymer resin and the like are typically exemplified. It is particularly preferable to use a homopolymer resin, a vinyl chloride-ethylene copolymer resin, a vinyl chloride-vinyl acetate copolymer resin, or the like that is a homopolymer of vinyl chloride. In the copolymer resin, the content of the comonomer is not particularly limited, and can be determined according to the required quality such as moldability.

As a ratio of the vinyl chloride resin with respect to the resin component whole quantity of a vinyl chloride-type resin composition, it is 50 mass% or more, for example, Preferably it is 80 mass% or more, More preferably, it is 90-100 mass%. In addition, a flame retardant, a stabilizer, an antiaging agent, a pigment, an inorganic filler, etc. can be added as needed.

As the vinyl chloride resin, a soft vinyl chloride resin can be suitably used. Examples of the soft vinyl chloride resin include a vinyl chloride resin having a viscosity average polymerization degree of 900 to 1300 and an appropriate amount of a stabilizer, a softening agent, and the like. If the degree of polymerization of the vinyl chloride resin is less than 900, the substrate may be soft and have low heat resistance. On the other hand, when the degree of polymerization exceeds 1300, the dispersibility of the additive of the vinyl chloride resin-based resin composition may be deteriorated and the flexibility of the pressure-sensitive adhesive film may be deteriorated. The polymerization degree is calculated according to JIS K6720-2 by dissolving 200 g of resin in 50 ml of nitrobenzene, measuring the specific viscosity of this polymer solution in a thermostatic bath at 30 ° C. using an Ubbelohde viscometer.

<Softener>
A softener can be blended with the base material in order to soften the base material. The kind of softening agent that can be used for the substrate is not particularly limited, and a known softening agent can be employed. For example, DOP (dioctyl phthalate), DINP (diisononyl phthalate), DINA (diisononyl adipate), DBP (dibutyl phthalate) described in the adhesive handbook (Japan Adhesive Industry Association, 3rd edition, P-69) Dibasic acid esters such as TOTM (tri-2-ethylhexyl trimellitic acid) and DIDP (diisodecyl phthalate); liquid rubbers such as liquid polyisobutylene, liquid isoprene and liquid butene; aromatic process oils, naphthenic process oils, Common softeners such as paraffinic oil, castor oil and tall oil can be used. These may be used singly or in combination of two or more. The softener ratio is preferably 15 to 45% by mass, more preferably 15 to 30% by mass, based on the total amount of the resin components of the vinyl chloride resin composition. If the softening agent is less than 15% by mass, the substrate may be hardened. On the other hand, if it exceeds 45% by mass, troubles such as bending of the substrate or shrinkage of the substrate may occur during the production of the substrate.

The thickness in particular of a base material is not restrict | limited, Preferably it is 10-500 micrometers, More preferably, it is 12-200 micrometers, More preferably, it is 15-100 micrometers. In addition, the base material may have a single layer form or may have a multiple layer form.

The substrate may be subjected to various treatments such as back treatment, antistatic treatment, and undercoating treatment as necessary.

<II. Adhesive layer>
In the present invention, the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is 0.3 to 4% by mass of a softener, natural rubber and / or styrene-butadiene rubber (hereinafter referred to as “SBR”). And a graft polymer obtained by graft polymerization of an (meth) acrylic acid ester having an alkyl group.

<Adhesive base agent>
The adhesive contains natural rubber and / or styrene-butadiene rubber as an adhesive base.

Natural rubber is widely used as a base for adhesive compositions. SBR is a typical general-purpose rubber and is excellent in aging resistance, creep resistance, plasticizer resistance, and the like. Commercial products can be used for natural rubber and SBR.

As SBR, publicly known or commonly used SBR can be used. The ratio of styrene and butadiene as monomer components in SBR is not particularly limited. The type or grade of SBR is not particularly limited, and various types or grades of SBR can be used.

<Softener>
As the softening agent that can be blended in the pressure-sensitive adhesive layer, the above-mentioned known softening agents can be employed in the same manner as can be used for the substrate.
The content rate of the softening agent in an adhesive layer is 0.3-4 mass% with respect to an adhesive, Preferably it is 1-3 mass%. When the content of the softener is less than 0.3% by mass, the migration of the softener from the base material made of the vinyl chloride resin composition cannot be suppressed, and the cohesive strength of the pressure-sensitive adhesive is reduced, or the pasting time The adhesive strength increases with time, and adhesive residue may occur when the adhesive film is peeled off. On the other hand, if the content of the softening agent exceeds 4% by mass, the initial adhesive may have insufficient cohesive strength regardless of the elapsed time, and adhesive residue may be generated when the adhesive film is peeled off. When the softener is present in the pressure sensitive adhesive in the specific amount, the transition of the softener from the base material to the pressure sensitive adhesive can be suppressed by the principle of chemical equilibrium.

The softener content in the present invention is measured by the following method.
Device name: Gas Chromatography (GC JEOL Ltd.)
Test method: The pressure-sensitive adhesive of the pressure-sensitive adhesive film is peeled off and extracted with normal hexane and dried at 40 ° C. for measurement.

<Graft polymer>
The graft polymer in the present invention is excellent in softening agent resistance that hardly causes deterioration of adhesive properties, and also has an effect of further suppressing a decrease in adhesive cohesive force due to migration of the softening agent. Moreover, since the (meth) acrylic acid ester having an alkyl group is grafted, adhesion to various adherends and unwinding force can be improved, and efficiency of workability at low temperatures can be improved. The compounding quantity of a graft polymer is 10-50 mass parts with respect to 100 mass parts of adhesion base agents which consist of natural rubber and / or SBR, Preferably it is 20-50 mass parts. If the graft polymer is less than 10 parts by mass, appropriate adhesion and rewinding force to various adherends may not be obtained. On the other hand, if the graft polymer exceeds 50 parts by mass, the graft polymer may become too hard to be used as an adhesive.

The graft polymer has both a highly polar constituent molecule ((meth) acrylate ester having an alkyl group) and a low polar constituent molecule (natural rubber, SBR) in the molecular structure of the graft polymer. Adhesion to an adherend that is difficult to adhere as an adhesive film and high unwinding force can be exhibited. Therefore, since both constituent molecules need to be appropriately distributed, in the graft polymer, natural rubber and / or SBR is 60 to 80% by mass, and (meth) acrylic acid ester having an alkyl group is 20 to 40% by mass. It is preferable to polymerize so that. More preferably, it is preferable to polymerize 65 to 75% by mass of natural rubber and / or SBR and 25 to 35% by mass of (meth) acrylic acid ester having an alkyl group.

Such alkyl (meth) acrylic acid esters include methyl (meth) acrylate (hereinafter abbreviated as “MMA”), ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) Acrylate, undecyl (meth) acrylate, isoundecyl (meth) acrylate, dodecyl (meth) acrylate, isotridecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like. Used in combination of two or more. Of these, methyl (meth) acrylate, n-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are preferably used.

The Mooney viscosity of the graft polymer in the present invention is 60 to 90 Ms1 + 4 (100 ° C.), preferably 70 to 90 Ms1 + 4 (100 ° C.). When the Mooney viscosity of the graft polymer is less than 60 Ms1 + 4 (100 ° C.), the resistance to the fluidity of the pressure-sensitive adhesive is weak, and a high cohesive force may not be obtained. On the other hand, when the Mooney viscosity exceeds 90 Ms1 + 4 (100 ° C.), the cohesive force of the pressure-sensitive adhesive may become too high. The method for adjusting the Mooney viscosity includes known methods, and is not particularly limited. For example, mastication using an open roll, a Banbury mixer, a kneader, or the like can be mentioned. Among them, the method of mastication with an open roll is preferable because the Mooney viscosity can be easily adjusted. The measurement of Mooney viscosity is based on JIS K-6300.

<Additives>
For the adhesive, various additives as required, for example, various stabilizers such as plasticizers, ultraviolet absorbers, antioxidants, tackifiers, fillers, colorants, antistatic agents, foaming agents, surface active agents Various known additives such as an agent may be blended.

The tackifier resin used for the tackifier can be selected in consideration of the softening point, compatibility with each component, and the like. For example, terpene resin, rosin resin, hydrogenated rosin resin, chroman indene resin, styrene resin, aliphatic and alicyclic petroleum resin, terpene-phenol resin, xylene resin, other aliphatic hydrocarbon resins Or an aromatic hydrocarbon resin etc. can be mentioned. The softening point of the tackifying resin is 65 to 170 ° C, preferably 80 to 150 ° C. The compounding quantity of tackifying resin is 50-200 mass parts with respect to 100 mass parts of adhesives, Preferably it is the range of 100-150 mass parts. If the amount of tackifying resin is too small, the pressure-sensitive adhesive film may not be able to exhibit high adhesive strength. On the other hand, when there are too many tackifying resins, the adhesive force of an adhesive film may become too high.

<III. Adhesive film>
The pressure-sensitive adhesive film of the present invention includes a base material made of a vinyl chloride resin composition and a pressure-sensitive adhesive layer formed on at least one surface of the base material. Usually, the pressure-sensitive adhesive layer is formed only on one side of the substrate, but may be formed on both sides. The pressure-sensitive adhesive film can be produced by forming a pressure-sensitive adhesive layer on at least one surface of a substrate using a conventional method such as a coating method. The pressure-sensitive adhesive layer may be protected by a peeling substrate (peeling liner). Moreover, the adhesive film may have another layer (for example, intermediate | middle layer, undercoat layer etc.) in the range which does not impair the effect of this invention.

The means for forming the substrate is not particularly limited, but the above-mentioned various materials are used by conventional melt-kneading and various mixing devices (single- or twin-screw extruder, roll, Banbury mixer, various kneaders, etc.). Then, the components are mixed so that they are uniformly dispersed, and the mixture is formed into a substrate by a calender molding machine and cut into a desired tape width. As a roll arrangement method in calendar molding, for example, a known method such as L-type, reverse L-type, and Z-type can be adopted, and the roll temperature is usually set in the range of 150 to 200 ° C, preferably 160 to 180 ° C. .

The means for applying the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer to the substrate is not particularly limited. For example, a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, A spray coater can be used. Although the thickness after drying of an adhesive layer can be suitably selected in the range which does not impair adhesiveness or handleability, the thickness of an adhesive layer is 5-100 micrometers, for example, Preferably it is 10-50 micrometers. If it is thinner than this, the adhesive force and the unwinding force may be reduced. On the other hand, if it is thicker than this, the coating performance may be deteriorated, and adhesive residue may easily occur.

The pressure-sensitive adhesive film of the present invention can be produced as a pressure-sensitive adhesive tape (pressure-sensitive adhesive film wound in a roll shape) having a state or form wound in a roll shape by winding in a roll shape. When it is not wound into a roll, it can be produced as an adhesive sheet.
When the adhesive film is formed on the adhesive tape, the adhesive film can be wound into a roll by applying a release agent on the back surface (non-glue surface) of the adhesive film and providing a back treatment layer. The movement of the softener between them can be prevented more reliably. Similarly, the release liner is interposed between the surface of the pressure-sensitive adhesive layer of one pressure-sensitive adhesive film and the back surface of the other pressure-sensitive adhesive film by laminating the surface of the pressure-sensitive adhesive layer with the release surface of the release liner in contact with each other. The movement of the softener between the adhesive films can be prevented more reliably.

Hereinafter, the present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited to these examples.

The materials used in the examples are as shown below.
(1) Vinyl chloride resin: TH-1000 (manufactured by Taiyo PVC Co., Ltd .: degree of polymerization 1100), TH-1300 (manufactured by Taiyo PVC Co., Ltd .: degree of polymerization 1300)
(2) Softener: DINP (manufactured by DIC)
(3) Tackifier: C5C9 petroleum resin (Esso Chemical Co., softening point 94 ° C)
(4) Stabilizer: Ca—Zn stabilizer (manufactured by Mizusawa Chemical Co., Ltd.)
(5) Modifier: MBS (manufactured by Nippon Synthetic Rubber)
(6) Graft polymer obtained by graft-polymerizing MMA to natural rubber: MEGAPOLY30 (manufactured by ASIATIC: graft polymer obtained by graft-polymerizing 30% by mass of MMA to 70% by mass of natural rubber)
(7) Graft polymer obtained by graft-polymerizing MMA on natural rubber: MEGAPOLY50 (manufactured by ASIATIC: graft polymer obtained by graft-polymerizing 50% by mass of MMA to 50% by mass of natural rubber)
(8) Graft polymer obtained by graft polymerizing MMA on SBR: SGMM-30 (manufactured by Denki Kagaku Kogyo Co., Ltd .: graft polymer obtained by graft polymerizing 30% by mass of MMA to 70% by mass of SBR)
(9) Graft polymer obtained by graft polymerization of butyl methacrylate on SBR: SGBM-30 (manufactured by Denki Kagaku Kogyo Co., Ltd .: graft polymer obtained by graft polymerization of 30% by mass of butyl methacrylate on 70% by mass of SBR)
(10) Graft polymer obtained by graft polymerization of butyl acrylate on SBR: SGBA-30 (manufactured by Denki Kagaku Kogyo Co., Ltd .: graft polymer obtained by graft polymerization of 30% by mass of butyl acrylate on 70% by mass of SBR)

In Tables 1 and 2, “initial adhesive strength” was measured in accordance with JIS Z 0237. After leaving the adhesive film in an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH for 24 hours or more, the adhesive film is applied to various adherends (SUS, PE, PVC, PET) with 2000 g. The roller was reciprocated twice for pasting, and after 30 minutes, the 180 ° peel strength (N / 10 mm) was measured. 1 N / 10 mm or more is preferable.

In Tables 1 and 2, “change in adhesive strength with respect to SUS” was measured in accordance with JIS Z 0237. After leaving the adhesive film in an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH for 24 hours or more, the adhesive film was attached to a SUS304 steel plate by reciprocating a 2000 g roller twice. After 1 minute, 180 degree peel strength (N / 10 mm) was measured after 1 month. Also, after leaving the adhesive film in the evaluation test chamber set at −20 ± 2 ° C. for 24 hours or more, the adhesive film was attached to the SUS304 steel plate by reciprocating a 2000 g roller twice, and peeled 180 degrees after 30 minutes. The strength (N / 10 mm) was measured. In any case, 1N / 10 mm or more is preferable.

In Tables 1 and 2, “holding force” was measured according to JIS Z 0237. After allowing the adhesive film to stand for 24 hours or more in an evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH, a SUS304 steel plate is used as the adherend, and the size is 20 × 20 mm. An adhesive film was affixed. Thereafter, under an atmosphere of 40 ° C., a load of 500 g was applied in the direction of gravity, and the falling time (minute) of the weight was measured at n = 3 or more. The numerical values in the table are average values. 300 minutes or more is good.

In Tables 1 and 2, “rewinding force” was measured according to JIS Z 0237. When the adhesive film is rewound at a speed of 15.8 m / min for about 3 seconds after being left in the evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH for 24 hours or more. Were measured at n = 3 or more. The numerical values in the table are average values. The range of 6-8 N / 10 minutes is good.

In Tables 1 and 2, “peeling” was measured according to JIS G 4305. After leaving the adhesive film in the evaluation test chamber set at a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH for 24 hours or more, the adhesive film is pressure-bonded to the SUS304 steel plate, 30 minutes after the initial, and 7 days later. The wearing state was visually observed, and the superiority or inferiority was evaluated according to the following criteria. The crimping method was performed in one reciprocation at a crimping speed of 5 mm / s using a 200 g roller according to JIS K 6253.
Good: No peeling

In Tables 1 and 2, “adhesive residue” was measured in accordance with JIS G 4305. After the adhesive film is allowed to stand for 24 hours or more in an evaluation test chamber set to a temperature of 23 ± 2 ° C. and a humidity of 50 ± 5% RH, the adhesive film is pressure-bonded to a SUS304 steel plate, 30 minutes after the initial, and one month later. The adhesive film was peeled off at a rate of 300 mm / min in the 180 ° direction, and the surface of the SUS304 steel plate after peeling was visually observed, and the superiority or inferiority was evaluated according to the following criteria. The crimping method was performed by one reciprocation at a crimping speed of 5 mm / s using a 200 g roller in accordance with JIS K 6253.
Good: No glue residue Bad: There is glue residue

Example 1
(I) 100 parts by mass of a vinyl chloride resin having a polymerization degree of 1100 (TH-1000 manufactured by Taiyo PVC Co., Ltd.), 25 parts by mass of DINP (manufactured by DIC) as a softening agent, C5C9 petroleum resin (manufactured by Esso Chemical Co., Ltd.) as a tackifier , Softening point 94 ° C.) 10 parts by mass, 2 parts by mass of MBS (manufactured by Nippon Synthetic Rubber Co., Ltd.) as a modifier, 2 parts by mass of Ca—Zn-based stabilizer (manufactured by Mizusawa Chemical Co., Ltd.), St acid ( 0.2 parts by mass of Nippon Oil & Fats Co., Ltd. and 2 parts by mass of MMA (manufactured by Kaneka Chemical Co., Ltd.) were mixed with a Henschel mixer, and a sheet having a thickness of 120 μm was formed by calendar molding (roll temperature: 145 to 180 ° C.). A sheet obtained by winding the sheet at a specified length (20 m) was annealed at 120 ° C. for 8 hours to obtain a substrate.
(Ii) 100 parts by mass of natural rubber (Mooney viscosity = 45), 20 parts by mass of graft polymer (MEGAPOLY30 manufactured by ASIATIC) obtained by graft polymerization of 30% by mass of MMA to 70% by mass of natural rubber, DINP (DIC) 100 parts by mass of a terpene resin (YShara Chemical YS Resin PX-1000) as a tackifier resin, 4 ethyl 6-tert-butylphenol (Kawaguchi Chemical Co., Ltd.) as an anti-aging agent 2 parts by mass of ANTAGE W-500) were mixed in toluene so as to be based on 30% by mass, and blended to obtain an adhesive.
(Iii) Apply a pressure-sensitive adhesive on one side of the substrate with a reverse roll coater, and after passing through the drying process, form a pressure-sensitive adhesive layer with a thickness of 20 μm after drying, cut into a tape with a width of 25 mm, A film was obtained.

(Examples 2-9)
A pressure-sensitive adhesive film was produced in accordance with Example 1 except that the composition of the pressure-sensitive adhesive and the substrate was variously changed as shown in Table 1.

(Comparative Examples 1-6)
A pressure-sensitive adhesive film was produced according to Example 1 except that the composition of the pressure-sensitive adhesive was variously changed as shown in Table 2.

As is clear from Tables 1 and 2, according to the present invention, the initial adhesive strength (30 minutes after application) on various adherends (SUS, PE, PVC, PET) is excellent. Further, even when the adhesive strength with SUS is changed with time (from 30 minutes to 1 month, a low temperature of −20 ° C.), high adhesive strength is maintained. From these facts, it can be seen that an adhesive film with a small amount of softener transfer from the base material to the adhesive, excellent adhesive force, unwinding force and holding force and less adhesive residue on the adherend can be easily obtained. .

Claims (5)

A pressure-sensitive adhesive film comprising a base material comprising a vinyl chloride resin composition and a pressure-sensitive adhesive layer formed on at least one side of the base material, wherein the pressure-sensitive adhesive layer is
(I) an adhesive base agent comprising natural rubber and / or styrene-butadiene rubber;
(Ii) scan styrene - containing butadiene rubber 60 to 80 wt%, having an alkyl group (meth) graft polymer and 20 to 40 wt% of acrylic acid ester is graft polymerized, and (iii) a softening agent,
(A) The softener is blended in an amount of 0.3 to 4% by mass with respect to the adhesive constituting the adhesive layer.
(B) The graft polymer is blended in an amount of 10 to 50 parts by mass with respect to 100 parts by mass of the adhesive base agent made of natural rubber and / or styrene-butadiene rubber.
(C) An adhesive film in which the Mooney viscosity of the graft polymer is a Mooney viscosity of 60 to 90 Ms1 + 4 (100 ° C.) in accordance with JIS K 6300.   The pressure-sensitive adhesive film according to claim 1, wherein the vinyl chloride resin composition contains 50% by mass or more of vinyl chloride resin with respect to the total amount of the resin components.   The pressure-sensitive adhesive according to claim 1, wherein the (meth) acrylic acid ester having an alkyl group is selected from the group consisting of methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and a mixture thereof. the film.   The pressure-sensitive adhesive film according to claim 1, wherein the softening agent is diisononyl phthalate. The substrate, the adhesive film according to softener 15-45 wt% including claim 1 with respect to the resin component total amount of the vinyl chloride resin composition.