JP2010121019A - Adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive film which has a proper adhesive strength and a stable peeling property to adherends having smooth surfaces, and little changes the adhesive strength with the passage of time. <P>SOLUTION: This adhesive film 10 comprises a substrate layer 11 and an adhesive layer 13. Therein, the substrate layer 11 comprises a low density polyethylene resin, and the adhesive layer 13 comprises a component A (50 to 90 pts of a flexible propylene polymer having an ethylene content of 0 to 30 mol% and an α-olefin content of 0 to 30 mol%, and having a melting point of <120°C or not having a melting point observed, when measured by differential scanning calorimetry), a component B (10 to 50 pts of isotactic polypropylene), and a component C (a hydrogenated diene-based copolymer), wherein the component C is contained in an amount of 1 to 30 pts per 100 pts of the total amount of the components A and B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an adhesive film, and more specifically, a molded product such as metal, glass, and plastic, a processed product, a painted product, and the like, in particular, by adhering to an adherent surface having a low surface roughness, The present invention relates to an adhesive film that protects scratches and dirt and can be easily peeled off during use.

  In the present specification, “ratio”, “part”, “%” and the like indicating the composition are based on mass unless otherwise specified, and the “/” mark indicates that they are integrally laminated. In addition, “EVA” is “ethylene-vinyl acetate copolymer”, “VA” is “vinyl acetate”, “E” is “ethylene”, and “LDPE” is an abbreviation of “low density polyethylene”, a functional expression, Common name or industry term.

  (Main use) The main use of the adhesive film of the present invention is to adhere to the surface of products and components such as building materials, daily necessities, stationery, home appliances, automobiles, various displays, etc. It protects scratches and dirt on the painted surface and can be peeled off during use. However, it is not particularly limited as long as it adheres to the adherend surface to protect scratches and dirt on the painted surface during transportation, storage, processing, and the like, and needs to be peeled off during use.

(Background Art) In an adherend having a decorative or glossy surface, an adhesive film is temporarily attached to protect the surface until use, and after transportation or storage, the adhesive film is peeled off and used. For example, there are various adherends such as a synthetic resin plate, a metal plate, a decorative plywood, and various nameplates.
For this reason, the pressure-sensitive adhesive film requires moderate adhesion to the adherend surface, flexibility not to damage the surface, corrosion resistance, and resistance to the environment. In addition, the adhesive film is consumed in a large amount, and after being used, it is peeled off and discarded, so that it can be manufactured at a low cost. Furthermore, these physical properties change little with the passage of time and temperature, and also require elongation, scratching, mechanical strength, and heat resistance when the coated plate is processed. Furthermore, an adhesive film made of a base material layer made of a thermoplastic resin such as polyolefin resin and an adhesive layer made of EVA, or an adhesive layer made of an elastomer such as a styrene block copolymer or a hydrogenated product thereof. Adhesive films are known. In some cases, these adhesive films have an increased adhesive strength under high temperature storage, making it difficult to peel off.
Conventionally, adherends are often given a design or the like, or have irregularities on the surface, or are often subjected to antifouling treatment, and an adhesive film in which an adhesive is applied to a plastic film Is generally used. Moreover, an adhesive film is normally manufactured in the winding state which rolled up the length of several hundred-several thousand m in roll shape, and post-processing, storage, and distribution | circulation are carried out. When the adhesive film is rewound from the wound form, it adheres between the base material layer and the adjacent adhesive layer, causing a blocking phenomenon, and is difficult to unwind. Or the adhesive film is broken.
Therefore, the pressure-sensitive adhesive film can be easily rewound in manufacturing and post-processing, and the pressure-sensitive adhesive strength increases due to changes with time under indoor and outdoor exposure and high-temperature storage, and peeling may be difficult. In particular, there is a demand for an adhesive film that has an appropriate adhesive strength and a stable peelability on an adherend having a smooth surface and has little change with time in strength.

(Prior art) Conventionally, as an adhesive film with moderate adhesive strength (peel strength) and stable peel strength even if the peel rate is changed at the time of peel (lessly dependent on peel rate), and with little change in adhesive strength over time Amorphous olefin copolymer (a); 20 to 80 parts by mass, crystalline olefin polymer (b); 3 to 30 parts by mass and a block copolymer having a styrene block or a crystalline olefin block (c) ); 10 to 50 parts by mass [the total of (a), (b) and (c) is 100 parts by mass], and the surface of the adhesive layer is a methacrylic resin with Ra = 4.5 μm One having an adhesive strength of 450 to 800 N / 50 mm with respect to an adherend surface made of a resin plate is known (for example, see Patent Document 1).
In addition, it has good adhesiveness that can satisfy the initial adhesiveness and aging after outdoor exposure and after storage at high temperature, has excellent peelability after outdoor exposure and after storage at high temperature, and good stress relaxation As the pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer capable of forming a pressure-sensitive adhesive layer, the pressure-sensitive adhesive sheet is formed on at least one side of the substrate. (A) Propylene, α-olefin having 4 to 12 carbon atoms and ethylene And (B) ethylene-vinyl acetate copolymer, hydrogenated product of CBC type thermoplastic elastomer having a crystalline olefin block, homopolypropylene, ethylene / α-olefin binary copolymer, propylene / α-olefin binary copolymer, low density polyethylene, high density polyethylene and linear (linear) low Any at least one or more resins that are selected from degrees polyethylene, it is known to use an adhesive comprising a (e.g., see Patent Document 2.).
In addition, it has high rigidity and high heat resistance, so there is no wrinkling or shrinkage of the film when used at high temperatures, low blocking force when unwinding, high initial adhesive strength, and small change with time in adhesive strength after application As a low-cost surface protection film, it is rolled into a product as a film in which a surface layer is laminated on one side of the base material layer and an adhesive layer is laminated on the opposite side. A surface protective film that is attached to an adherend and can be peeled off, wherein the base layer is made of a resin mainly composed of polypropylene, the surface layer is made of a resin mainly composed of polyethylene, and the adhesive layer is made of A surface protective film is known in which the rewinding force of a film made of an adhesive material mainly composed of an α-olefin copolymer having 2 to 12 carbon atoms is 200 g / 25 mm or less (for example, patent document) Reference.).
However, the composition of the base material layer and the pressure-sensitive adhesive layer of Patent Documents 1 to 3 is different from the present invention, and Patent Documents 1 to 3 also have an increase due to time-dependent changes in the adhesive strength under indoor outdoor exposure or high-temperature storage. There is a problem that peeling may be difficult.

JP 2007-76127 A JP-A-226814 Japanese Patent Laid-Open No. 11-21519

  In order to solve the above-described problems, the present inventors have made extensive studies and have completed the present invention. The purpose is to provide a pressure-sensitive adhesive film having an appropriate pressure-sensitive adhesive strength and stable peelability even on an adherend having a smooth surface, and having little change with time in the pressure-sensitive adhesive strength.

In order to solve the above problems, the pressure-sensitive adhesive film according to the invention of claim 1 is a pressure-sensitive adhesive film comprising a base material layer and a pressure-sensitive adhesive layer, wherein the base material layer is made of a low-density polyethylene resin, and the pressure-sensitive adhesive layer is Component A), (Component B), and (Component C) are included.
(Component A) Soft propylene polymer 50 having an ethylene content of 0 to 30 mol%, an α-olefin content of 0 to 30 mol%, a melting point of less than 120 ° C. or no melting point measured by differential scanning calorimetry ~ 90 parts by mass, (Component B) 10 to 50 parts by mass of isotactic polypropylene, (Component C) hydrogenated diene copolymer with respect to 100 parts by mass in total of (Component A) and (Component B) ˜30 parts by mass.
The pressure-sensitive adhesive film according to claim 2 is characterized in that the hydrogenated diene copolymer is a vinyl aromatic compound polymer block (A), a conjugated diene polymer, or a random copolymer block of a vinyl aromatic compound and a conjugated diene ( B), a taper block (C) in which vinyl aromatic compounds gradually increase among vinyl aromatic compounds and conjugated dienes, comprising at least block (A) and block (B) (A)-(B) block co-weight A block copolymer selected from a polymer, (A)-(B)-(A) block copolymer, and (A)-(B)-(C) block copolymer is hydrogenated to form a conjugated diene diene. One or a plurality of hydrogenated diene copolymers saturated with 80% or more of the heavy bonds.
In the pressure-sensitive adhesive film according to the invention of claim 3, the vinyl aromatic compound is styrene or α-methylstyrene, and the conjugated diene is 1,3-butadiene, isoprene, or 1,3-pentadiene, or It is what was made to be plural.
In the pressure-sensitive adhesive film according to the invention of claim 4, the base material layer comprises an intermediate layer and a back layer, the thickness of the intermediate layer occupies 50% or more of the thickness of the base material layer, and a colorant is present in the intermediate layer. It is added and manufactured by an inflation method.

According to the first to third aspects of the present invention, it is easy to unwind in manufacturing and post-processing, and under indoor and outdoor exposure and high-temperature storage, the adhesive strength increases with time, and peeling may be difficult. . In particular, even an adherend having a smooth surface can be provided with an adhesive film having an appropriate adhesive strength and a stable peelability and having little change with time in strength.
According to this invention of Claim 4, it can manufacture at lower temperature, the bridge | crosslinking and oxidation of material are suppressed, and external appearance with few fish eyes etc. can be improved. In addition, since coloring can be performed simultaneously with film formation, manufacturing costs can be reduced, and by coloring the intermediate layer, there is no color transfer to others, and forgetting to stick to the adherend or forgetting to peel off during use is prevented. An adhesive film that can be provided is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of an adhesive film showing one embodiment of the present invention.
FIG. 2 is a cross-sectional view of an adhesive film showing one embodiment of the present invention.

  (Adhesive Film) The adhesive film 10 of the present invention comprises an adhesive layer 13 and a base material layer 11 as shown in FIG. The adhesive layer 13 includes the following (component A) (component B) (component C), and the base material layer 11 is made of a low-density polyethylene resin. (Component A) is a soft propylene polymer having an ethylene content of 0 to 30 mol%, an α-olefin content of 0 to 30 mol%, a melting point measured by differential scanning calorimetry of less than 120 ° C, or no melting point observed. 50 to 90 parts by mass, (Component B) is 10 to 50 parts by mass of isotactic polypropylene, and (Component C) is a hydrogenated diene copolymer to a total of 100 parts by mass of (Component A) and (Component B). On the other hand, it is 5-30 mass parts.

  (Base Material Layer) As the base material layer 11, a low density polyethylene resin is used. Moreover, as the base material layer 11, as shown in FIG. 2, it is good also as multiple layers, for example, it is good also as two layers, the back surface layer 21 and the intermediate | middle layer 23. FIG. Preferably, the thickness of the intermediate layer 23 occupies 50% or more of the thickness of the base material layer 11, and by adding a colorant to the intermediate layer 23, the film can be colored at the same time as the film formation. In addition, by coloring the intermediate layer, it is possible to prevent forgetting to attach or peel off the adhesive film 10.

  (Adhesion layer) (Component A), (Component B) and (Component C) contained in the adhesion layer 13 will be described in detail.

  The soft propylene polymer of (Component A) (Component A) has a melting point of less than 120 ° C. or no melting point measured by differential scanning calorimetry. Here, the fact that the melting point is not observed means that a crystal melting peak having a heat of crystal melting of 1 J / g or more is not observed in the range of −40 ° C. to 200 ° C. The soft propylene polymer has a propylene-derived constitutional unit of 40 to 100 mol%, an ethylene-derived constitutional unit of 0 to 30 mol%, and a C4 to C20 α-olefin-derived constitutional unit of 0 to 30 mol%. (Wherein the total of propylene, ethylene, and α-olefin having 4 to 20 carbon atoms is 100 mol%). More preferably, the structural unit derived from propylene is 60 to 80 mol%, the structural unit derived from ethylene is 12 to 23 mol%, and the structural unit derived from an α-olefin having 4 to 20 carbon atoms is in the range of 0 to 20 mol%. is there. A soft propylene polymer containing propylene, ethylene, and an α-olefin component having 4 to 20 carbon atoms in such a content has good compatibility with isotactic polypropylene, transparency and flexibility, heat resistance, Compression strain resistance can be obtained. Flexibility, heat resistance, and compression strain resistance are considered to contribute to prevention of adhesive strength under high temperature storage.

  The soft propylene polymer of the present invention can be produced using a metallocene catalyst for the production of isotactic polypropylene. For example, Mitsui Chemical's Notio has been promoted, and one grade is selected as appropriate. Or it can blend and use.

  (Component B) (Component B) may be a polypropylene homopolymer or a random copolymer of propylene and α-olefin as isotactic polypropylene, and has a melting point Tm of 140 measured by a differential scanning calorimeter. -170 ° C, preferably 145-170 ° C, more preferably 150-165 ° C. Examples of the α-olefin used in the case of the random copolymer include ethylene and α-olefins having 4 to 20 carbon atoms, preferably ethylene, 1-butene and 1-pentene, and the propylene content is 80. -100 mol%, preferably 85-100 mol%, more preferably 90-100 mol%. In addition, it is not preferable to use a block copolymer as (Component B) because the surface roughness of the pressure-sensitive adhesive layer becomes high and the pressure-sensitive adhesiveness is hardly expressed.

  (Component C) The vinyl aromatic compound used in the hydrogenated diene copolymer of (Component C) is styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenyl. Styrene, N, N-diethyl-p-aminoethylstyrene, vinylpyridine and the like can be mentioned, and styrene and α-methylstyrene are particularly preferable. Conjugated dienes are 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5- Examples include diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, etc. In order to obtain a hydrogenated diene copolymer excellent in physical properties, 1,3-butadiene, isoprene 1,3-pentadiene is preferred.

  The hydrogenated diene copolymer includes the vinyl aromatic compound polymer block (A), a conjugated diene polymer, or a random copolymer block (B) of a vinyl aromatic compound and a conjugated diene, and a vinyl aromatic compound. The conjugated diene is obtained by hydrogenating a diene block copolymer containing at least (A) and (B) of the tapered block (C) in which the vinyl aromatic compound gradually increases. Here, the diene block copolymer preferably has a configuration of (A)-(B), (A)-(B)-(A), or (A)-(B)-(C). Further, the block (A) and the block (B) do not necessarily need to be clearly distinguished, and a tapered portion where the vinyl aromatic compound gradually decreases as the block (A) shifts to the block (B). A configuration having Furthermore, in the hydrogenated diene copolymer of the present invention, 80% or more, preferably 90% or more of the conjugated diene portion of the block (B) needs to be hydrogenated and saturated. Here, when the hydrogenation rate is 80% or less, the heat resistance and weather resistance are poor. Examples of such a hydrogenated diene copolymer include Dynalon from JSR, Septon from Kuraray, Kraton from Kraton Polymer, Shibster from Kaneka, and the like.

  In the present invention, the hydrogenated diene copolymer as described above is added to the adhesive layer in an amount of 1 to 30 parts by mass with respect to a total of 100 parts by mass of the soft polypropylene polymer and isotactic polypropylene. By laminating the adhesive layer and a base material layer made of low-density polyethylene, the adhesive strength with respect to a smooth methacrylic resin surface can be stabilized within the range of 0.05 to 0.5 N, and the unwinding force is also 0. An adhesive film of less than 1 N / 25 mm can be obtained. Moreover, by setting it as such an adhesive layer composition, the raise of the adhesive strength under high temperature storage can be prevented.

(Thickness) The pressure-sensitive adhesive film 10 of the present invention is basically a film having a two-layer structure of pressure-sensitive adhesive layer 13 / base material layer 11, and the thickness is preferably in the range of 40 μm to 120 μm. If it is less than 40 μm, the rigidity at the time of bonding and peeling is insufficient, and if it exceeds 120 μm, the cost is increased, which is not preferable.
The thickness of the adhesive layer is preferably in the range of 10 to 30% of the total thickness. If the thickness of the pressure-sensitive adhesive layer 13 is less than 10% of the total thickness, there is a possibility that the strength of the pressure-sensitive adhesive layer 13 may be partially increased due to the variation in the thickness of the pressure-sensitive adhesive layer 13, which is not preferable. Further, if it exceeds 30% of the whole, the rigidity of the film is insufficient, which is not preferable.

  (Production) The pressure-sensitive adhesive film 10 of the present invention is preferably formed by an inflation method. In general, the T-die method has a higher film forming temperature than the inflation method, so that the decomposition of the soft propylene polymer and isotactic polypropylene used for the adhesive layer and the base material layer is promoted, or hydrogenated diene is used. Oxidation of the conjugated diene unsaturation in the system copolymer may be promoted. Degradation of polypropylene and oxidation of a hydrogenated diene copolymer cause fish eyes and are not preferable.

  (Change in adhesive force over time) In the case of an adhesive film in which the conventional adhesive layer is made of an elastomer such as EVA, a styrene block copolymer, or a hydrogenated product thereof, the adhesive force changes over time at high temperatures or for long-term storage, In many cases, it has risen to make it difficult to peel off the adherend, and the adhesive remains on the surface of the adherend after peeling. For this reason, it is preferable that the adhesive strength with respect to a smooth methacrylic resin surface is in the range of 0.05 to 0.5 N as the adhesive strength even in the initial adhesive strength and storage at high temperatures and for a long period of time.

  (Rewinding force) Moreover, the adhesive film 10 is usually wound up in a roll shape, and rewound again and used. When unwinding, the unwinding force (peeling force between the adhesive layer and the adjacent base material layer) unwinding force is less than 0.1 N / 25 mm. If the unwinding force increases, it becomes difficult to unwind at the time of use, the handleability is poor, and if it is remarkable, the adhesive film is broken.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, it is not limited to this. In addition, except a solvent, each composition of each layer is a mass part of solid content conversion.

(Example 1) Using the 65 mmφ extruder, 90 mmφ extruder, 65 mmφ extruder, the following adhesive layer 13, intermediate layer 23 and back layer 21 were extruded, and the adhesive layer 13, intermediate layer 23 and back surface were subjected to multilayer inflation method. The pressure-sensitive adhesive film 10 of Example 1 having an overall thickness of 50 μm was obtained as follows.
・ Adhesive layer 10μ (65mmφ extruder)
Mitsui Chemicals Notio PN0040 65 parts Prime polymer E233GV 35 parts Clayton polymer Clayton MD6649 16 parts Intermediate layer 30μ (90 mmφ extruder)
Sumitomo Chemical F425P 100 parts ・ Back layer 10μ (65mmφ extruder)
Sumitomo Chemical F425P 100 parts

(Example 2) An adhesive film 10 of Example 2 was obtained in the same manner as in Example 1 except that the following adhesive layer 13, intermediate layer 23, and back layer 21 were used, and the thicknesses were set as follows.
・ Adhesive layer 7μ (65mmφ extruder)
Mitsui Chemicals Notio PN0040 65 parts Prime polymer E233GV 35 parts Clayton polymer Clayton MD6649 16 parts Intermediate layer 30μ (90 mmφ extruder)
Sumitomo Chemical F425P 100 parts ・ Backside layer 13μ (65mmφ extruder)
Sumitomo Chemical F425P 100 parts

Example 3 An adhesive film 10 of Example 3 was obtained in the same manner as in Example 1 except that the following adhesive layer 13, intermediate layer 23 and back layer 21 were used.
・ Adhesive layer 10μ (65mmφ extruder)
Mitsui Chemicals Notio PN2060 75 parts Prime polymer E233GV 25 parts Clayton polymer Clayton MD6649 25 parts Intermediate layer 30μ (90 mmφ extruder)
Mitsubishi Chemical LF547 100 parts ・ Back layer 10μ (65mmφ extruder)
Mitsubishi Chemical LF547 100 parts

(Example 4) An adhesive film 10 of Example 4 was obtained in the same manner as in Example 1 except that the following adhesive layer 13, intermediate layer 23 and back layer 21 were used.
・ Adhesive layer 10μ (65mmφ extruder)
Mitsui Chemicals Notio PN2060 63 parts Prime polymer E233GV 37 parts Clayton polymer Clayton MD6649 25 parts Intermediate layer 30μ (90 mmφ extruder)
Mitsubishi Chemical LF547 100 parts Dainichi Seika PE-M E7608 (light blue) 3 parts ・ Back layer 10μ (65mmφ extruder)
Mitsubishi Chemical LF547 100 parts

Comparative Example 1 An adhesive film 10 of Comparative Example 1 was obtained in the same manner as in Example 1 except that the following adhesive layer 13, intermediate layer 23 and back layer 21 were used.
・ Adhesive layer 10μ (65mmφ extruder)
Mitsui DuPont V5714 (VA 16% EVA) 100 parts ・ Intermediate layer 30μ (90mmφ extruder)
Sumitomo Chemical F425P 100 parts ・ Back layer 10μ (65mmφ extruder)
Sumitomo Chemical F425P 100 parts

(Comparative Example 2) A pressure-sensitive adhesive film 10 of Comparative Example 2 was obtained in the same manner as in Example 1 except that the following pressure-sensitive adhesive layer 13, intermediate layer 23 and back layer 21 were used and the thicknesses were set to the following values.
・ Adhesive layer 7μ (65mmφ extruder)
Nippon Polyethylene Kernel KF360T (density 0.898) 90 parts Clayton polymer Clayton MD6649 10 parts Intermediate layer 30μ (90mmφ extruder)
Sumitomo Chemical F425P 100 parts ・ Backside layer 13μ (65mmφ extruder)
Sumitomo Chemical F425P 100 parts

(Comparative Example 3) A pressure-sensitive adhesive film 10 of Comparative Example 3 was obtained in the same manner as in Example 1 except that the following pressure-sensitive adhesive layer 13, intermediate layer 23, and back layer 21 were used and the thicknesses were set to the following.
・ Adhesive layer 10μ (65mmφ extruder)
Ube Industries Umerit 1540F (density 0.913) 100 parts ・ Intermediate layer 30μ (90mmφ extruder)
Mitsubishi Chemical LF547 100 parts ・ Back layer 10μ (65mmφ extruder)
Mitsubishi Chemical LF547 100 parts

(Evaluation method) Evaluation was performed by initial adhesive strength, adhesive strength after storage, and rewinding strength.
(Initial adhesive strength; test method) The adhesive films 10 of Examples 1 to 4 and Comparative Examples 1 to 3 are defined in JIS Z0237 on a 3 mm thick acrylic plate (methacrylic plate) and a 180 μ polyester sheet (Toyobo A4100, PET). Using the resulting rubber roll (weight 2 kg, width 45 mm, roll diameter 95 mm, rubber hardness 80 ± 5 Hs), one reciprocal pressure bonding was performed, and the peel strength after one hour was measured at a tensile speed of 300 mm / min, and the initial adhesive strength and did.

  (Adhesive strength after storage; test method) The above initial adhesive strength; adhesive films 10 of Examples 1 to 4 and Comparative Examples 1 to 3 obtained by the test method are attached to an acrylic plate (methacrylic plate) and a PET sheet. In the attached state, it preserve | saved 23 degreeC x 7 days and 50 degreeC x 7 days, and measured the peeling strength after a preservation | save. In addition, what was preserve | saved 50 degreeC x 7 days was, after cooling at 23 degreeC for 1 hour, peel strength was measured at a tensile rate of 300 mm / min.

(Rewinding force) Each of the adhesive films 10 of Examples 1 to 4 and Comparative Examples 1 to 3 was cut out in a state where 10 or more films were overlapped, cut into a 25 mm width strip, The peel strength between the pressure-sensitive adhesive layer surface and the substrate layer of the pressure-sensitive adhesive film adjacent thereto was measured at a pulling speed of 300 mm / min, and used as the rewind force.
Table 1 shows the results of initial adhesive strength, adhesive strength after storage, and unwinding force.

(Evaluation results) In Examples 1 to 4, even after storage for 7 days at 23 ° C. and 50 ° C., the increase and decrease from the initial adhesive force was extremely small for the acrylic plate and the PET sheet, and the unwinding force was 0. It was able to work well with 03-0.04.
In Comparative Example 1, the increase from the initial adhesive strength is small after storage at 23 ° C. for 7 days, but the increase is large after storage at 50 ° C. for 7 days, and peeling may be difficult depending on storage conditions. It was thought that there was. The unwinding force was 0.04, which was a workable range. In Comparative Example 2, the initial adhesive strength was large, and after storage for 7 days at 23 ° C., the initial adhesive strength increased slightly, and after storage for 7 days at 50 ° C., it increased significantly. Although the unwinding force can be set to 0.18, the load on the machine and the efficiency are significantly reduced. In the comparative example 3, it did not adhere to an acrylic board and a PET sheet, and did not function as an adhesive film.
As is clear from the above results, the pressure-sensitive adhesive film 10 of the present invention is excellent in peelability, rewinding property, and storage property, and contributes industrially.

It is sectional drawing of the adhesive film which shows one Example of this invention. It is sectional drawing of the adhesive film which shows one Example of this invention.

Explanation of symbols

10: Adhesive film 11: Base material layer 13: Adhesive layer 21: Back layer 23: Intermediate layer

Claims (4)

In the pressure-sensitive adhesive film comprising the base material layer and the pressure-sensitive adhesive layer, the base material layer is made of a low-density polyethylene resin, and the pressure-sensitive adhesive layer contains the following (Component A), (Component B) and (Component C). Adhesive film.
(Component A) Soft propylene polymer 50 having an ethylene content of 0 to 30 mol%, an α-olefin content of 0 to 30 mol%, a melting point of less than 120 ° C. or no melting point measured by differential scanning calorimetry ~ 90 parts by mass (Component B) 10-50 parts by mass of isotactic polypropylene (Component C) 1-30 of the hydrogenated diene copolymer with respect to 100 parts by mass in total of (Component A) and (Component B) Parts by mass The hydrogenated diene copolymer is a vinyl aromatic compound polymer block (A), a conjugated diene polymer or a random copolymer block of vinyl aromatic compound and conjugated diene (B), a vinyl aromatic compound and a conjugated diene. (A)-(B)-(B)-(A)-(B) block copolymer containing at least the block (A) and the block (B) of the taper block (C) in which the vinyl aromatic compound gradually increases. A hydrogenated diene obtained by hydrogenating a block copolymer selected from A) block copolymer and (A)-(B)-(C) block copolymer to saturate 80% or more of the double bond of the conjugated diene. The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film is one or a plurality of copolymer. The vinyl aromatic compound is styrene or α-methylstyrene, and the conjugated diene is 1,3-butadiene, isoprene, 1,3-pentadiene, or a plurality thereof. The adhesive film as described. The base layer is composed of an intermediate layer and a back layer, the thickness of the intermediate layer occupies 50% or more of the thickness of the base layer, a colorant is added to the intermediate layer, and the base layer is manufactured by an inflation method. The pressure-sensitive adhesive film according to any one of claims 1 to 3.

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