JP2008087169A - Pressure-sensitive adhesive film and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To set a pressure-sensitive adhesive before processed into a pressure-sensitive adhesive film to pressure-sensitive adhesive strength to a degree easy to preserve and to process the pressure-sensitive adhesive to manufacture the pressure-sensitive adhesive film before enhancing the pressure-sensitive adhesive strength. <P>SOLUTION: The pressure-sensitive adhesive film is constituted by laminating a pressure-sensitive adhesive layer, which contains an olefinic copolymer obtained by polymerizing at least two kinds of monomers selected from the group consisting of ethylene and a 3-20C α-olefin and satisfies (1) both of crystal fusion heat quantity and crystalization heat quantity have no peak of 1 J/g or above in differential scanning heat-of-quantity of measurement according to JIS K 7122 and (2) a molecular weight distribution (Mw/Mn) is 3 or below and a base material layer containing a thermoplastic resin and the pressure-sensitive adhesive layer is irradiated with energy rays of 1-100 kGy. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an adhesive film and a method for producing the same.

Conventionally, an adhesive film using an acrylic or (meth) acrylic adhesive, an emulsion adhesive film thereof, or the like has been widely used as an adhesive film. However, since these are produced through a step of dissolving or dispersing the pressure-sensitive adhesive (or its precursor) in a solvent, there is a problem that the solvent tends to remain in the pressure-sensitive adhesive film.

As an adhesive film obtained without using a solvent, for example, Patent Document 1 discloses at least two types selected from the group consisting of a base material layer made of a thermoplastic resin and ethylene and an α-olefin having 3 to 20 carbon atoms. An adhesive film comprising an adhesive layer comprising an olefin copolymer containing an olefin polymerization unit and satisfying the following (a) and (b) is disclosed.
(A) In the differential scanning calorimetry according to JIS K7122, the olefin copolymer has a peak with a heat of crystal melting of 1 J / g or more and a peak with a heat of crystallization of 1 J / g or more. I don't have it.
(B) The molecular weight distribution (Mw / Mn) of the olefin copolymer is 3 or less.

JP 2002-302659 A

The pressure-sensitive adhesive film is extremely excellent in adhesive strength. For this reason, it may be difficult to store the olefin copolymer constituting the pressure-sensitive adhesive layer for a long time before processing into the pressure-sensitive adhesive film. It was. However, if the adhesive strength of the pressure-sensitive adhesive is reduced for easy storage, the pressure-sensitive adhesive film obtained by processing the pressure-sensitive adhesive naturally has poor adhesive strength. Therefore, the present inventors have determined that the pressure-sensitive adhesive before being processed into a pressure-sensitive adhesive film has a pressure-sensitive adhesive force that can be easily stored, and that the pressure-sensitive adhesive must be improved after the pressure-sensitive adhesive is processed into a pressure-sensitive adhesive film. The present invention has been conceived.

That is, the present invention provides an olefin system satisfying the following (1) and (2) obtained by polymerizing at least two monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms. A pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer containing a copolymer and a base material layer containing a thermoplastic resin are laminated, and the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer irradiated with an energy ray of 1 to 100 kGy. is there.
(1) In differential scanning calorimetry according to JIS K7122, there is no peak with a crystal melting heat quantity of 1 J / g or more and a peak with a crystallization heat quantity of 1 J / g or more.
(2) The molecular weight distribution (Mw / Mn) is 3 or less.
Furthermore, the present invention provides an olefin system satisfying the following (1) and (2) obtained by polymerizing at least two types of monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms. It is a manufacturing method of the adhesive film which irradiates the 1-100 kGy energy beam to the layer surface containing the said olefin type copolymer of the laminated | multilayer film by which the layer containing a copolymer and the layer containing a thermoplastic resin were laminated | stacked.
(1) In differential scanning calorimetry according to JIS K7122, there is no peak with a crystal melting heat quantity of 1 J / g or more and a peak with a crystallization heat quantity of 1 J / g or more.
(2) The molecular weight distribution (Mw / Mn) is 3 or less.

According to the method for producing an adhesive film of the present invention, the adhesive force can be improved after film processing. The adhesive film of the present invention is excellent in adhesive strength.

In the pressure-sensitive adhesive film of the present invention, an energy ray is applied to a layer containing an olefin copolymer obtained by polymerizing at least two types of monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms. An adhesive film in which an adhesive layer formed by irradiation and a base material layer containing a thermoplastic resin are laminated. Hereinafter, the layer before irradiation with energy rays is referred to as “a layer containing an olefin copolymer”, and the layer after irradiation is referred to as “adhesion layer”.
The olefin copolymer in the layer containing the olefin copolymer in the pressure-sensitive adhesive film of the present invention is at least two olefin monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms. A copolymer obtained by polymerization, which satisfies the following (1) and (2).
(1) In differential scanning calorimetry according to JIS K7122, there is no peak with a crystal melting heat quantity of 1 J / g or more and a peak with a crystallization heat quantity of 1 J / g or more.
(2) The molecular weight distribution (Mw / Mn) is 3 or less.

Examples of the α-olefin having 3 to 20 carbon atoms include linear and branched α-olefins, and examples of the linear α-olefin include propylene, 1-butene and 1-pentene. 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nanodecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene, and 2,2,4 -Trimethyl-1-pentene can be exemplified. Among these, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-pentene, 3-methyl-1-butene, and 4-methyl-1- Pentene is preferred.

In addition to at least two kinds of olefin monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms, the copolymer may contain a polyene compound monomer, a cyclic olefin monomer, if necessary. A monomer selected from the group consisting of a monomer and a vinyl aromatic compound monomer may be copolymerized.

In the differential scanning calorimetry according to JIS K 7122, the olefin copolymer of the present invention has a peak of 1 J / g or more in crystallization K and a heat of crystallization of 1 J / g. It is a copolymer having no peak of any peak of g or more, and the molecular weight distribution (Mw / Mn) is 3 or less. Preferably, the heat of crystal fusion does not have a peak of 0.5 J / g or more, and the heat of crystallization preferably does not have a peak of 0.5 J / g or more.

The molecular weight distribution of the olefin copolymer is determined from the weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of polystyrene measured by GPC. Specifically, about 5 mg of a sample is dissolved in 5 ml of o-dichlorobenzene to obtain a solution having a concentration of about 1 mg / ml, 400 μl of the solution is injected into a GPC apparatus, an elution temperature of 140 ° C., and an elution solvent flow rate of 1.0 ml. / Min, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the sample can be measured and determined. The molecular weight distribution is preferably 2.8 or less, more preferably 2.5 or less.

The adhesive film may be peeled off after being applied to the adherend. When the adhesive film is used on the premise that it is peeled off, the intrinsic viscosity [η] of the olefin copolymer is preferably 0.5 / g, and is 1.0 to 8.0 dl / It is more preferable that it is g, and it is still more preferable that it is 1.3-6.0 dl / g. By using such an olefin copolymer, the pressure-sensitive adhesive layer hardly remains on the adherend surface when it is peeled off.

The polymerization method of the olefin copolymer in the present invention is not particularly limited, and polymerization may be performed using a known polymerization catalyst such as a Ziegler-Natta type catalyst or a single site catalyst (for example, a metallocene catalyst). Can do.

Among these, a metallocene catalyst is generally used. From the viewpoint of flexibility of the resulting olefin copolymer, the metallocene catalyst has at least one cyclopentadiene type anion skeleton, and has a C1 symmetrical structure. A transition metal complex of Group 3 to Group 12 of the periodic table is preferred.

The layer containing the olefin polymer in the present invention may contain a thermoplastic resin other than the olefin polymer, a thermoplastic elastomer, an additive, or the like. Examples of the thermoplastic resin include polypropylene resin; polyethylene resin such as high density polyethylene, medium density polyethylene, low density polyethylene and linear low density polyethylene (LLDPE); copolymer resin of ethylene and acrylic acid monomer; ethylene Copolymer resin of ethylene and vinyl acetate; copolymer resin of ethylene and methacrylic acid monomer; polybutene resin; poly-4-methyl-pentene-1 resin; polystyrene resin; polyester resin; polyamide resin; A polyphenylene oxide resin; a polyacetal resin; and a polycarbonate resin. Among these, it is preferable that a polyolefin resin such as a polypropylene resin or a polyethylene resin is included.

In the case where the pressure-sensitive adhesive film of the present invention is used as a pressure-sensitive adhesive film that is used on the premise of peeling, an olefin copolymer is used in order to prevent the pressure-sensitive adhesive layer from remaining on the adherend surface when peeled. The layer to be contained preferably contains a polyolefin resin having a melting point of 80 to 176 ° C, and more preferably contains a polyolefin resin having a melting point of 90 to 176 ° C. The polyolefin resin preferably has a heat of crystal fusion of 30 to 120 J / g, and more preferably 60 to 120 J / g.

When the adhesive layer contains a thermoplastic resin other than the olefin copolymer and the olefin copolymer, the blending ratio of the olefin copolymer and the thermoplastic resin is not particularly limited. From the viewpoint of the flexibility and heat resistance of the adhesive layer, the blending ratio (weight ratio) of olefin copolymer / thermoplastic resin is preferably 95/5 to 1/99, more preferably 90/10 to 3/97. Particularly preferably, it is 80/20 to 5/95.

Additives contained in the layer containing the olefin copolymer include stabilizers such as anti-aging agents, antioxidants, ozone degradation inhibitors, ultraviolet absorbers, and light stabilizers; antistatic agents, slip agents. Internal release agents, colorants, dispersants, antiblocking agents, lubricants, fillers such as fluororesins; and mineral oil softeners such as naphthenic oils and paraffinic mineral oils. Moreover, the tackifier may be contained.

The layer containing the olefin polymer is formed by a known method using a crosslinking agent (which is a common method in rubber vulcanization) such as sulfur crosslinking, peroxide crosslinking, metal ion crosslinking, silane crosslinking, and resin crosslinking. May be cross-linked. The additive required for crosslinking is not particularly limited. The thermoplastic resin composition comprising an olefin copolymer and a thermoplastic resin may be dynamically crosslinked in the presence of a crosslinking agent.

When the layer containing the olefin copolymer contains other components such as a thermoplastic resin and an additive, a composition obtained by melt-kneading the olefin copolymer and other components in advance is usually used. Use. Examples of the method for producing the composition include a method of kneading each component with a known kneading apparatus such as a rubber mill, a Brabender mixer, a Banbury mixer, a pressure kneader, a ruder, and a twin screw extruder. The kneading apparatus may be either a closed type or an open type, but a closed type apparatus that can be replaced with an inert gas is preferable. The kneading temperature is usually 120 to 250 ° C, preferably 140 to 240 ° C. The kneading time depends on the type and amount of components used and the type of kneading apparatus, and is usually about 3 to 10 minutes when a kneading apparatus such as a pressure kneader or a Banbury mixer is used. In the kneading step, a method of kneading each component in a lump may be adopted, or a multistage division kneading method in which a part of each component is kneaded and then the remainder is added to continue kneading may be adopted. Good.

The base material layer in the pressure-sensitive adhesive film of the present invention contains a thermoplastic resin. The thermoplastic resin is not particularly limited, and is random or at least one monomer selected from the group consisting of homopropylene, propylene, a small amount of ethylene, and an α-olefin having 4 to 20 carbon atoms. Polypropylene resins such as block copolymers; polyethylene resins such as low density polyethylene, medium density polyethylene, high density polyethylene and linear low density polyethylene; poly-4-methyl-pentene-1; Examples thereof include a polymer; an ethylene-vinyl acetate copolymer; an ethylene-methyl methacrylate copolymer, and a combination thereof. Among these, from the viewpoint of obtaining an adhesive film having an excellent balance between adhesiveness and peelability, a polyethylene resin or a polypropylene resin having good compatibility with the olefin copolymer constituting the adhesive layer in the adhesive film of the present invention. Is preferred. By selecting the same type of resin as the olefin copolymer constituting the adhesive layer as the thermoplastic resin constituting the base material layer, the base material layer and the adhesive layer are less likely to peel off and are excellent in recyclability. It can be set as an adhesive film.

When a polypropylene resin is used as the resin constituting the substrate layer of the pressure-sensitive adhesive film of the present invention, it is preferable to use homopolypropylene having excellent heat resistance from the viewpoint of improving the productivity of the pressure-sensitive adhesive film.

Moreover, as a resin constituting the base material layer, an adhesive film having excellent hand cutting properties by using a polypropylene-based resin having an MFR of 30 g / 10 min or more at 230 ° C. and a load of 2.16 kg measured according to JIS K 6922-1. It can be.

The base material layer may contain a colorant such as a pigment, an antioxidant, a dispersant, a filler, an antistatic agent, a release agent, and the like. The base material layer may contain a thermoplastic elastomer or the like. As the thermoplastic elastomer, an olefin thermoplastic elastomer that is a copolymer of ethylene and α-olefin such as EPR and EBR is preferably used.

The base material layer in the pressure-sensitive adhesive film of the present invention may be a single layer or a multilayer. When the base material layer is a multilayer, it may be a laminated film of a thermoplastic resin layer and another film made of paper, cloth, metal or the like having good hand cutting properties.

The thickness of the base material layer in the pressure-sensitive adhesive film of the present invention is generally 1 to 100 μm, preferably 10 to 50 μm, more preferably 15 to 25 μm. It is technically difficult to produce a film having a thickness of less than 1 μm, and when it exceeds 100 μm, the hand-cut property of the adhesive film may be hindered. The surface of the base material layer may be subjected to treatment such as corona discharge treatment, plasma treatment, flame treatment, electron beam irradiation treatment, and ultraviolet irradiation.

The pressure-sensitive adhesive film of the present invention may be a pressure-sensitive adhesive film having a pressure-sensitive adhesive layer on one side of the base material layer, or may be a pressure-sensitive adhesive film having pressure-sensitive adhesive layers on both sides of the base material layer.

The thickness of the adhesive film of this invention is 0.001-5 mm normally, Preferably it is 40-400 micrometers. By forming the thickness of the pressure-sensitive adhesive film of the present invention from 40 to 400 μm and forming a plurality of groove-shaped recesses on at least one surface, a pressure-sensitive adhesive film having excellent hand cutting properties can be obtained. In particular, the depth of the recess is 0.03 to 0.3 mm, the distance between the recesses is 0.5 to 5 mm, and the difference between the thickness of the adhesive film and the depth of the recess is 0.01 to 0.1 mm. By forming the film, it is possible to obtain an adhesive film having extremely excellent hand cutting properties. The depth of the recesses is preferably 0.04 to 0.12 mm, and the interval between the recesses is preferably 0.6 to 1.4 mm.

As for the shape of the recessed part provided in the adhesive film of this invention, the shape of a buoy (V) trough shape continuously formed from one end of the adhesive film to the other end, for example is mentioned. Although the shape of such a recess is preferable from the viewpoint of hand cutting properties and good appearance of the cut portion when cut by hand, the shape of the recess according to the adhesive film of the present invention is not limited to this shape. , A shape like a U-shaped valley may be used, and a recess formed discontinuously with a cut may be used.

The method for producing a pressure-sensitive adhesive film of the present invention includes an olefin-based copolymer of a laminated film in which a layer containing an olefin copolymer that satisfies the above requirements (1) and (2) and a layer containing a thermoplastic resin are laminated. This is a method of irradiating a layer surface made of a polymer with an energy ray of 1 to 100 kGy. As a method for producing a laminated film in which a layer containing an olefin copolymer and a layer containing a thermoplastic resin are laminated, a method of co-extrusion using an apparatus such as an inflation film production apparatus or a T-die film production apparatus, A method of extrusion coating (also referred to as “extrusion laminating method”) can be exemplified.

The pressure-sensitive adhesive film of the present invention may be stretched in a uniaxial direction or a biaxial direction as necessary. As a preferred method for uniaxial stretching, a commonly used roll stretching method can be exemplified. Examples of the biaxial stretching method include a sequential stretching method in which biaxial stretching is performed after uniaxial stretching, and a simultaneous biaxial stretching method such as a tubular stretching method.

By irradiating the layer surface containing the olefin copolymer of the laminated film with an energy ray of 1 to 100 kGy, the adhesive force can be increased more than before irradiation. Examples of energy rays to be irradiated include electromagnetic waves, particle beams, and combinations thereof. Examples of electromagnetic waves include ultraviolet rays (UV), visible light, infrared rays, γ rays, and X rays, and examples of particle rays include electron beams (EB) and α rays. Among these, it is preferable to use ultraviolet rays (UV) or electron beams (EB). These energy rays can be irradiated using a known apparatus. The acceleration voltage when irradiating an electron beam (EB) is 0.1 to 10 MeV. When irradiating with ultraviolet rays (UV), a lamp having a radiation wavelength of 200 nm to 450 nm can be suitably used. In the case of an electron beam (EB), for example, a tungsten filament can be used as the radiation source. Is mentioned. Thus, an adhesive layer can be formed by irradiating an energy ray to the layer containing an olefin copolymer.

When the pressure-sensitive adhesive film of the present invention is overlaid, from the viewpoint of ease of pulling out the pressure-sensitive adhesive film from the roll, that is, from the viewpoint of self-peeling property, a release paper is sandwiched in the roll, or a release agent is applied to the surface of the base material layer. Also good. Examples of the release agent include silicone release agents and non-silicone release agents. Examples of the silicone release agent include thermosetting silicone release agents, photocurable silicone release agents, copolymer release agents with other polymers, and blend release agents with other polymers. Examples of the non-silicone release agent include a long-chain alkyl polymer, polyolefin, and a release agent mainly composed of a fluorine compound.

When the pressure-sensitive adhesive film of the present invention has a plurality of groove-shaped recesses on one surface, it can be produced by the following method. That is, a laminated film having a thickness of 40 to 400 μm in which a layer containing an olefin copolymer and a layer containing a thermoplastic resin are laminated is pressed with a squeeze roll and a smooth roll, and the following (3 )-(5), a plurality of groove-shaped recesses are formed, and then the layer surface containing the olefin copolymer is irradiated with an energy ray of 1 to 100 kGy.
(3) Depth of recess is 0.03-0.3mm
(4) The interval between the recesses is 0.5 to 5 mm.
(5) The difference between the thickness of the adhesive film and the depth of the recess is 0.01 to 0.1 mm.

In the case of forming the recesses by the above method, the film still in the softened state immediately after being extruded from the extruder may be pressed as it is between the squeeze roll and the smooth roll, or a film at room temperature ( After the film in the solidified state is heated and softened, it may be pressed between the squeeze roll and the smooth roll. In the case of producing a film having a concave portion by the above method, unless the shape of the concave portion is deformed to an inconvenient level, for the purpose of improving the physical properties of the film, for example, by a squeeze roll and a smooth roll. The film may be stretched after pressing.

When forming a plurality of groove-shaped recesses on both sides of the pressure-sensitive adhesive film of the present invention, after forming the recesses on one surface by the above-described method, the recesses may be formed on the opposite surface in the same manner. Alternatively, a laminated film may be pressed between the squeezing rolls using a pair of squeezing rolls.

Fields in which the adhesive film of the present invention is suitably used include electronics fields such as back grind tape for semiconductor wafers, dicing tape, protective tape for transporting electronic components, and protective tape for printed circuit boards; protective film for window glass, baking coating Automotive fields such as film for protection, guard film for protecting automobiles to users, marking film for display, marking film for decoration, and sponge tape for cushioning, protection, heat insulation and soundproofing; adhesive bandages and transdermal patches Medical and hygiene materials fields; and electrical insulation, identification, duct construction, window glass protection, curing, packaging, packing, office, household, fixing, binding and repair The housing / construction field such as adhesive film and protective film can be exemplified. The adhesive film of the present invention particularly protects the surface of a synthetic resin plate, a stainless steel plate (for example, for building materials), an aluminum plate, a decorative plywood, a steel plate, a glass plate, a home appliance, a precision machine, and an automobile body at the time of manufacture. To prevent scratches when stacking, storing and transporting articles; and to prevent scratches when secondary processing (for example, bending and pressing) of articles. Can be preferably used.

The following examples further illustrate the present invention, but the present invention is not limited thereto.

The physical properties of the olefin copolymer were measured by the following methods.
1. The composition analysis qualitative analysis of the olefin copolymer, the IR analysis, rocking vibration of methylene group ethylene units 720 cm ^-1 is the rocking vibration of the methyl group of the propylene unit to 1154cm ^-1, 770cm ^-1 Since the horizontal vibration of the methyl group in the ethyl group of the 1-butene unit was observed, it was confirmed that the obtained copolymer had an ethylene unit, a propylene unit and a 1-butene unit.

About the quantitative analysis, it calculated | required in the following procedures (i)-(ii) using the apparatus by the brand name made from Bruker company AC-250.
(I) First, in the ¹³ C-NMR spectrum, from the ratio between the spectral intensity of carbon derived from the methyl group in the propylene unit and the spectral intensity of carbon derived from the methyl group in the 1-butene unit, The composition ratio with 1-butene unit is calculated.
(Ii) Next, in the ¹ H-NMR spectrum, from the ratio of the spectral intensity of hydrogen derived from a methine group and a methylene group and the spectral intensity of hydrogen derived from a methyl group, an ethylene unit, a propylene unit and 1-butene The composition ratio of the unit is calculated.

2. Crystal melting point (° C), crystal melting heat (mj / mg), crystallization temperature (° C), crystallization heat (mj / mg)
Using a differential scanning calorimeter (DSC220C type) manufactured by Seiko Denshi Kogyo Co., Ltd., the measurement was performed at a temperature rising rate and a temperature falling rate of 10 ° C./min.

3. Molecular weight distribution (Mw / Mn)
About 5 mg of a sample is dissolved in 5 ml of o-dichlorobenzene to obtain a solution having a concentration of about 1 mg / ml. 400 μl of the solution is injected into a GPC apparatus, and the conditions of elution temperature 140 ° C. and elution solvent flow rate 1.0 ml / min are obtained. Below, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the sample, and molecular weight distribution (Mw / Mn) were calculated | required. Here, Waters 150C type (refractive index detector) is used as the GPC apparatus, and the trade name Showa Denko Column A-80M is used as the column, and the molecular weight of the sample (converted to the molecular weight of polystyrene). As a standard substance for determining the molecular weight, Tosoh polystyrene having a molecular weight range of 68 to 8,400,000 was used.

4). A solution of 3 mg / ml concentration obtained by dissolving 300 mg of intrinsic viscosity sample in 100 ml of tetralin is diluted 1/2, 1/3 and 1/5, and the viscosity of each diluted solution is 135 ± 0.1 ° C. Each measurement was performed three times using an Ubbelohde viscometer, and an average value of the measured values was obtained.

The physical properties of the adhesive film were measured by the following methods.
1. It measured by the method which consists of procedure (1)-(4) below peeling strength.
(1) Affix an adhesive film on an acrylic board.
(2) This is pressure-bonded with a rubber-coated roller weighing 2 kg.
(3) Leave at 23 ° C. for 24 or 96 hours, and 70 ° C. for 24 or 96 hours.
(4) In an atmosphere of 23 ° C., the force required to peel the adhesive film from the acrylic plate under the conditions of a peeling width of 25 mm, a peel angle of 180 °, and a peeling speed of 300 mm / min was measured. g / 25 mm).

[Reference Example] (Production of olefin copolymer)
From the bottom of a 100 L stainless steel polymerizer equipped with a stirrer, hexane (solvent) was 83 L / hour, propylene was 12 kg / hour, 1-butene was 1.3 kg / hour, dimethylsilyl (tetra Methylcyclopentadienyl) (3-tert-butyl-5-methyl-2-phenoxy) titanium dichloride 0.005 g / hour, triphenylmethyltetrakis (pentafluorophenyl) borate 0.260 g / hour, triisobutylaluminum Are continuously fed at a rate of 1.654 g / hr, while the polymer solution in the polymerizer is continuously withdrawn from the top of the polymerizer at a rate of maintaining 100 L, while hydrogen as a molecular weight regulator. 3 is used to circulate cooling water through a jacket attached to the outside of the polymerization vessel. Propylene and 1-butene were copolymerized at 4 ° C. After adding a small amount of ethanol to the polymerization solution extracted from the polymerization vessel to stop the polymerization reaction, depolymerization and water washing are performed, and then the solvent is removed with steam in a large amount of water to obtain a copolymer. The copolymer was taken out and dried under reduced pressure at 80 ° C. day and night. A propylene-1-butene copolymer (hereinafter referred to as “olefin copolymer”) was obtained at a rate of 2.9 kg / hour. Table 1 shows the physical properties of the olefin copolymer.

[Example 1]
50 parts by weight of an olefin copolymer and 50 parts by weight of a polypropylene resin (FS2011DG3 manufactured by Sumitomo Chemical Co., Ltd .; MFR = 2.5 g / 10 min at 230 ° C. and 2.16 Kg load) are manufactured by Brabender Plasticorder PLV151 type Was pre-kneaded at 200 ° C. for 2 minutes at a screw speed of 10 rpm, and then kneaded at 200 ° C. for 10 minutes at 80 rpm to obtain a resin composition for forming a layer containing an olefin copolymer. The resin composition and a propylene-based resin (FLX81K9 manufactured by Sumitomo Chemical Co., Ltd .; MFR = 7.0 g / 10 min at 230 ° C. under a load of 2.16 Kg) were used in a co-extrusion test laminator manufactured by Modern Machinenary Co., Ltd. Supplied to the extruder, co-extruded at an extruder temperature of 230 to 250 ° C., a die temperature of 250 to 280 ° C., a cooling temperature of 30 to 40 ° C. with a chill roll, and a take-off speed of 5 to 10 m / min. Obtained. Using an electron beam irradiation apparatus manufactured by Iwasaki Electric Co., Ltd., the layer surface containing the olefin copolymer of the laminated film was irradiated with an electron beam of 50 kGy to obtain an adhesive film. The adhesive film was allowed to stand at 23 ° C. for 24 hours, 23 ° C. for 96 hours, 70 ° C. for 24 hours, and 70 ° C. for 96 hours, and then the adhesive strength was measured. Moreover, it measured similarly about the adhesive film obtained by irradiating an electron beam of 100 kGy. The results are shown in Table 2.

[Example 2]
Example except that a resin composition obtained by kneading 70 parts by weight of an olefin copolymer and 330 parts by weight of FS2011DG was used as a resin composition for forming a layer containing an olefin copolymer. In the same manner as in No. 1, an adhesive film was produced. The results evaluated in the same manner as in Example 1 are shown in Table 2.

[Example 3]
Adhesion using 56 parts by weight of an olefin copolymer and 44 parts by weight of a polyethylene resin having a grade name F208-0 manufactured by Sumitomo Chemical Co., Ltd. (MFR = 2.0 g / 10 min at 190 ° C. under a load of 2.16 kg) A 45 μm adhesive film was obtained in the same manner as in Example 1 except that a layer was obtained and that the base material layer was laminated with the adhesive layer extruded from an extruder using a PET film manufactured by Toyobo Co., Ltd. Was manufactured and irradiated with an electron beam. Table 2 shows the physical properties of this adhesive film.

[Comparative Example 1]
The laminated film obtained in Example 1 was allowed to stand at 23 ° C. for 24 hours, 23 ° C. for 96 hours, 70 ° C. for 24 hours, and 70 ° C. for 96 hours without being irradiated with an electron beam, and then the adhesive strength was measured. The results are shown in Table 3.

[Comparative Example 2]
The laminated film obtained in Example 2 was allowed to stand at 23 ° C. for 24 hours, 23 ° C. for 96 hours, 70 ° C. for 24 hours, and 70 ° C. for 96 hours without being irradiated with an electron beam, and then the adhesive strength was measured. The results are shown in Table 3.

[Comparative Example 3]
The laminated film obtained in Example 3 was allowed to stand at 23 ° C. for 24 hours, 23 ° C. for 96 hours, 70 ° C. for 24 hours, and 70 ° C. for 96 hours without being irradiated with an electron beam, and then the adhesive strength was measured. The results are shown in Table 3.

Claims (4)

An olefin copolymer satisfying the following (1) and (2), which is obtained by polymerizing at least two monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms. An adhesive film in which an adhesive layer and a base material layer containing a thermoplastic resin are laminated, wherein the adhesive layer is an adhesive layer irradiated with an energy ray of 1 to 100 kGy.
(1) In differential scanning calorimetry according to JIS K7122, there is no peak with a crystal melting heat quantity of 1 J / g or more and a peak with a crystallization heat quantity of 1 J / g or more.
(2) The molecular weight distribution (Mw / Mn) is 3 or less. 2. The adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a thickness of 40 to 400 μm and has a plurality of groove-shaped concave portions that satisfy the following (3) to (5) on at least one surface. Adhesive film.
(3) Depth of recess is 0.03-0.3mm
(4) The interval between the recesses is 0.5 to 5 mm.
(5) The difference between the thickness of the adhesive film and the depth of the recess is 0.01 to 0.1 mm. An olefin copolymer satisfying the following (1) and (2), which is obtained by polymerizing at least two monomers selected from the group consisting of ethylene and an α-olefin having 3 to 20 carbon atoms. A method for producing a pressure-sensitive adhesive film, comprising irradiating an energy ray of 1 to 100 kGy on a layer surface containing the olefin copolymer of a laminated film in which a layer and a layer containing a thermoplastic resin are laminated.
(1) In differential scanning calorimetry according to JIS K7122, there is no peak with a crystal melting heat quantity of 1 J / g or more and a peak with a crystallization heat quantity of 1 J / g or more.
(2) The molecular weight distribution (Mw / Mn) is 3 or less. The method for producing an adhesive film according to claim 3, wherein a laminated film having a thickness of 40 to 400 μm in which a layer containing an olefin copolymer and a layer containing a thermoplastic resin are laminated is formed by a squeeze roll and a smooth roll. Pressing to form a plurality of groove-shaped recesses satisfying the following (3) to (5) on one surface, and then irradiating the layer surface containing the olefin copolymer with 1 to 100 kGy of energy rays. A method for producing a pressure-sensitive adhesive film.
(3) Depth of recess is 0.03-0.3mm
(4) The interval between the recesses is 0.5 to 5 mm.
(5) The difference between the thickness of the adhesive film and the depth of the recess is 0.01 to 0.1 mm.