JP2009299038A - Pressure-sensitive adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive film having a sufficient initial adhesive force is difficult to cause variation by the progress of time or a heat treatment, and difficult to generate a residual paste after peeled off the pressure-sensitive adhesive film from the adhered subject. <P>SOLUTION: The pressure-sensitive adhesive film is composed of a base layer laminated with a pressure-sensitive adhesive layer formed from a resin composition containing 70-99 pts.wt. of a component (A) and 30-1 pts.wt. of a component (B). The component (A): an ethylene-ethylenic unsaturated ester copolymer (A1) and/or an ethylene-α-olefin copolymer (A2), (a-1): 0.01 or over of tanδ at 23°C, (a-2): 1-50 g/10 min of MFR and (a-3): 1.0 wt.% or less of a heptane extract. The component (B): an ethylene-α-olefin copolymer, (b-1): 3 g or over/10 min of MFR, (b-2): 1.5-7.0 wt.% of a heptane extract and (b-3): 910 kg/m<SP>3</SP>or less of density. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an adhesive film.

Generally, the pressure-sensitive adhesive film is composed of at least two layers of a pressure-sensitive adhesive layer and a base material layer that supports the pressure-sensitive adhesive layer. Among such adhesive films, those used to cover the surface of resin plates such as acrylic plates and polycarbonate plates, and metal plates such as aluminum plates and stainless steel plates are called surface protective films. It is one of the important uses of film. Resin plates and metal plates coated with a surface protective film are stored for several days to half a year in a warehouse or factory until shipment. For this reason, the adhesive strength of the surface protection film is small even if it is stored in the warehouse, and adhesive remains on the resin plate and metal plate even after peeling off the surface protection film after long-term storage until shipment. The characteristic which does not do was called for. In particular, when a surface protective film is used for an optical member such as a polarizing plate or a retardation plate used for forming a liquid crystal panel or an elliptical polarizing plate obtained by laminating them, the above characteristics are strongly demanded.
Therefore, Patent Document 1 describes a pressure-sensitive adhesive for a surface protective film using an acrylic polymer having a specific composition and elastic modulus as a component of the pressure-sensitive adhesive.

JP-A-5-163468

However, the surface protective film using an acrylic polymer for the adhesive layer as described above still has insufficient performance.
Under such circumstances, the problem to be solved by the present invention, that is, the object of the present invention is that the initial adhesive force is sufficient as compared with the conventional adhesive film, and the fluctuation of the adhesive force due to aging or heat treatment hardly occurs, and The present invention relates to providing an adhesive film in which an adhesive residue hardly occurs after the adhesive film is peeled off from an adherend.

That is, the present invention is an adhesive film in which an adhesive layer and a base material layer are laminated, and the adhesive layer comprises 70 to 99 parts by weight of the following component (A) and 30 to 1 part by weight of component (B). It is the adhesive film formed from the resin composition (however, the sum total of a component (A) and a component (B) shall be 100 weight part).
Component (A): ethylene-ethylenically unsaturated ester copolymer (A1) that satisfies the following conditions (a-1) and (a-2) and / or the following conditions (a-1)-(a-3) -Α-olefin copolymer (A2) satisfying all the requirements
(A-1): tan δ at 23 ° C. is 0.01 or more (a-2): Melt flow rate (MFR) is 1 to 50 g / 10 minutes (a-3): Heptane extract amount is 1.0 wt% or less (B): an ethylene-α-olefin copolymer that satisfies all the following conditions (b-1)-(b-3) (b-1): a melt flow rate (MFR) of 3 g or more / 10 minutes (b-2) ): Heptane extraction amount is 1.5 wt% or more and 7.0 wt% or less (b-3): density is 910 kg / m ³ or less

  According to the present invention, there is provided an adhesive film that has sufficient initial adhesive strength, hardly changes in adhesive strength due to aging or heat treatment, and hardly generates adhesive residue after peeling the adhesive film from the adherend. The

The pressure-sensitive adhesive film of the present invention is a pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer and a base material layer are laminated. This adhesion layer is formed from the resin composition containing the following components (A) and a component (B).
Component (A): ethylene-ethylenically unsaturated ester copolymer (A1) that satisfies the following conditions (a-1) and (a-2) and / or the following conditions (a-1)-(a-3) -Α-olefin copolymer (A2) satisfying all the requirements
(A-1): tan δ at 23 ° C. is 0.01 or more (a-2): Melt flow rate (MFR) is 1 to 50 g / 10 minutes (a-3): Heptane extract amount is 1.0 wt% or less (B): an ethylene-α-olefin copolymer that satisfies all the following conditions (b-1)-(b-3) (b-1): a melt flow rate (MFR) of 3 g or more / 10 minutes (b-2) ): Heptane extraction amount is 1.5 wt% or more and 7.0 wt% or less (b-3): density is 910 kg / m ³ or less

  As the component (A), an ethylene-ethylenically unsaturated ester copolymer (A1) and / or an ethylene-α-olefin copolymer (A2) can be used. Examples of the ethylene-ethylenically unsaturated ester copolymer (A1) include ethylene-vinyl ester copolymers such as ethylene-vinyl acetate copolymer and ethylene-vinyl propionate copolymer; ethylene-methyl methacrylate copolymer And ethylene-unsaturated carboxylic acid alkyl ester copolymers such as ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer. Among these, an ethylene-vinyl acetate copolymer and an ethylene-methyl methacrylate copolymer are preferable, and an ethylene-methyl methacrylate copolymer is more preferable.

From the viewpoint of initial adhesive strength, the ethylene-ethylenically unsaturated ester copolymer (A1) has a tan δ at 23 ° C. of 0.01 or more, preferably 0.05 or more, more preferably 0.07 or more. It is. Further, 23 ° C. tan δ is usually 0.2 or less, preferably 0.18 or less, and more preferably 0.17 or less.
Tan δ is measured by the following method. The resin to be measured is pressed to produce a measurement sheet having a width of 3 mm and a thickness of 0.3 mm. The measurement sheet was measured using a viscoelasticity measuring device DMS200 manufactured by Seiko Denshi Kogyo Co., Ltd. at a distance between chucks of 20 mm, a temperature rising rate of 5 ° C./min, and a frequency of 5 Hz, and a value of 23 ° C. was read.

  In the ethylene-ethylenically unsaturated ester copolymer (A1), the content of structural units based on ethylene is usually 50% by weight or more, preferably 60 to 99% by weight, more preferably 70 to 97% by weight, More preferably, it is 75-95 weight%, Most preferably, it is 75-80 weight%. However, the content of all structural units in the ethylene-ethylenically unsaturated ester copolymer is 100% by weight. In addition, content of the structural unit based on ethylene is measured by the infrared method.

The tan δ at 23 ° C. of the ethylene-ethylenically unsaturated ester copolymer (A1) depends on the type and content of the ethylenically unsaturated ester used. For example, when vinyl acetate is used as the ethylenically unsaturated ester, ethylene -When the vinyl acetate-derived monomer unit content in the vinyl acetate copolymer is 5% by weight, the tan δ of the ethylene-vinyl acetate copolymer is about 0.13, and the vinyl acetate-derived monomer unit content Tan δ of the ethylene-vinyl acetate copolymer is about 0.05 when the content is 26% by weight, and tan δ of the ethylene-vinyl acetate copolymer is about 0 when the monomer unit content derived from vinyl acetate is 20% by weight. .17.
When methyl methacrylate is used as the ethylenically unsaturated ester, when the content of monomer units derived from methyl methacrylate contained in the ethylene-methyl methacrylate copolymer is 5% by weight, the ethylene-methyl methacrylate copolymer The tan δ of the coalescence is about 0.01, and when the monomer unit content derived from methyl methacrylate is 30% by weight, the tan δ of the ethylene-methyl methacrylate copolymer is about 0.05, the monomer derived from methyl methacrylate When the unit content is 20% by weight, the tan δ of the ethylene-methyl methacrylate copolymer is about 0.17.

  The melt flow rate (MFR) of the ethylene-ethylenically unsaturated ester copolymer (A1) is 1 to 50 g / 10 min. More preferably, it is 3-20 g / 10min, More preferably, it is 5-15g / 10min. An ethylene-ethylenically unsaturated ester copolymer having an MFR in the above range is excellent in processability. The MFR is measured under the conditions of a load of 21.18 N and a temperature of 190 ° C. according to JIS K7210 (1995).

  As a method for producing the ethylene-ethylenically unsaturated ester copolymer (A1), a known method is used. For example, the ethylene-unsaturated ester compound and the ethylenically unsaturated ester compound can be obtained by a high pressure radical polymerization method, a solution polymerization method, an emulsion polymerization method, The method of copolymerizing with ethylene can be mentioned.

Examples of the α-olefin in the ethylene-α-olefin copolymer (A2) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention include propylene, butene-1, pentene-1, 4-methylpentene-1, Hexene-1, octene-1, decene-1, etc. are mentioned. From the inexpensive point, it is preferably propylene, butene-1, hexene-1, octene-1, more preferably butene-1, hexene-1, Octene-1.

Examples of the ethylene-α-olefin copolymer (A2) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention include an ethylene-propylene copolymer, an ethylene-butene-1 copolymer, and ethylene-4-methylpentene. -1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-propylene-butene-1 copolymer, etc., preferably ethylene-propylene copolymer, ethylene -Butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, more preferably ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene -Octene-1 copolymer.

From the viewpoint of initial adhesive strength, the ethylene-α-olefin copolymer (A2) contained in the adhesive layer of the adhesive film of the present invention has a tan δ at 23 ° C. of 0.01 or more, preferably 0.05 or more. And more preferably 0.07 or more. Further, 23 ° C. tan δ is usually 0.2 or less, preferably 0.18 or less, and more preferably 0.17 or less.
The method for measuring tan δ is the same as (A1).

  The melt flow rate (MFR) of the ethylene-α-olefin copolymer (A2) is 1 to 50 g / 10 minutes. More preferably, it is 3-20 g / 10min, More preferably, it is 5-15g / 10min. An ethylene-α-olefin copolymer having an MFR in the above range is excellent in processability. The MFR is measured under the conditions of a load of 21.18 N and a temperature of 190 ° C. according to JIS K7210 (1995).

  The amount of heptane extracted from the ethylene-α-olefin copolymer (A2) is 1.0 wt% or less, and preferably 0.8% or less from the viewpoint of adhesive residue when the adhesive film is peeled off from the adherend. . The amount of heptane extracted can be obtained by immersing 100 g of the pellet of the measurement sample in 250 cc of heptane at 30 ° C. for 9 hours, suction filtration with a glass filter, and measuring the amount extracted into the heptane solution.

The density of the ethylene -α- olefin copolymer (A2), from the viewpoint of initial adhesion, preferably at 920 kg / ^{m 3} or less, more preferably 915 kg / ^{m 3,} and most preferably 910 kg / ^{m 3} or less It is. Further, from the viewpoint of handling such as mutual adhesion of ethylene-α-olefin copolymer pellets, the density is preferably 860 kg / m ³ or more.

  The ethylene-α-olefin copolymer (A2) is a copolymer polymerized by a homogeneous catalyst from the viewpoint of suppressing adhesive residue after the pressure-sensitive adhesive film of the present invention is peeled off from the adherend. preferable. Here, the homogeneous catalyst is a catalyst containing a transition metal compound having a group having a cyclopentadiene type anion skeleton, that is, a so-called metallocene compound. More preferred metallocene compounds are those represented by the general formula MLcXn-c (wherein M is a group 4 or lanthanide series transition metal atom of the periodic table of elements. L is a group or heteroatom having a cyclopentadiene-type anion skeleton). A group having a cyclopentadiene-type anion skeleton, wherein a plurality of Ls may be cross-linked to each other, X is a halogen atom, hydrogen or a hydrocarbon group having 1 to 20 carbon atoms N represents a number corresponding to the valence of the transition metal atom, and c is an integer of 0 <c ≦ n. The above transition metal compounds may be used alone or in combination of two or more.

Furthermore, as the catalyst containing the above transition metal compound, the transition metal compound includes an organoaluminum compound such as triethylaluminum and triisobutylaluminum, an alumoxane compound such as methylalumoxane, and / or trityltetrakispentafluorophenylborate, N, A combination of ionic compounds such as N-dimethylanilinium tetrakispentafluorophenylborate is used. Examples of the catalyst containing the transition metal compound include transition metal compounds, organoaluminum compounds, alumoxane compounds, and / or ionic compounds, particulate inorganic carriers such as SiO ₂ and Al ₂ O ₃ , polyethylene, polystyrene A catalyst supported on a particulate organic polymer carrier such as the above may be used.

  Examples of the polymerization method of the ethylene-α-olefin copolymer (A2) include a solution polymerization method, a slurry polymerization method, a high-pressure ion polymerization method, and a gas phase polymerization method. Preferred are a gas phase polymerization method and a high pressure ion polymerization method.

  The component (A) contained in the adhesive layer of the adhesive film of the present invention is an ethylene-ethylenically unsaturated ester copolymer (A1) and / or an ethylene-α-olefin copolymer (A2). As the component (A), one or more ethylene-ethylenically unsaturated ester copolymers (A1) or one or more ethylene-α-olefin copolymers (A2) may be used. However, (A1) and (A2) may be blended by a known method. In the case of blending both, the weight ratio can be arbitrarily selected. Usually, the component (A1) / component (A2) is 95/5 to 5/95, preferably 90/10 to 10/90, More preferably, it is 80/20-20/80.

Component (B) contained in the adhesive layer of the adhesive film of the present invention is an ethylene-α-olefin copolymer. The α-olefin in the component (B) is an α-olefin having 3 or more carbon atoms. For example, propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, Examples include decene-1 and the like, preferably propylene, butene-1, hexene-1 and octene-1, and more preferably butene-1 and hexene-1.

  Examples of the ethylene-α-olefin copolymer (component (B)) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention include an ethylene-propylene copolymer, an ethylene-butene-1 copolymer, and ethylene-4. -Methylpentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-propylene-butene-1 copolymer and the like, preferably ethylene-propylene copolymer A copolymer, an ethylene-butene-1 copolymer, an ethylene-hexene-1 copolymer, and an ethylene-octene-1 copolymer, more preferably an ethylene-butene-1 copolymer and an ethylene-hexene-1 copolymer. It is a coalescence.

The melt flow rate (MFR) of the ethylene-α-olefin copolymer (component (B)) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is 3 g or more / 10 minutes, preferably 4 to 20 g / 10 minutes. More preferably, it is 5-10 g / 10 minutes. The ethylene-α-olefin copolymer (component (B)) having an MFR in the above range is excellent in processability. The MFR is measured under conditions of a temperature of 190 ° C. and a load of 21.18 N according to JIS K7210.

  The amount of heptane extracted from the ethylene-α-olefin copolymer (component (B)) contained in the adhesive layer of the adhesive film of the present invention is 1.5 wt% or more and 7.0 wt% or less. By using a copolymer (component (B)) with ethylene-α-olefin having a heptane extraction amount of 1.5 wt% or more, the pressure-sensitive adhesive film of the present invention is less susceptible to fluctuations in pressure-sensitive adhesive force due to aging or heat treatment. Become. Further, by using an ethylene-α-olefin copolymer (component (B)) having a heptane extraction amount of 7.0 wt% or less, an adhesive residue is generated after the adhesive film of the present invention is peeled off from the adherend. It becomes difficult to do. In addition, the heptane extraction amount of a component (component (B)) is calculated | required by the method similar to a component (A2).

The density of the ethylene-α-olefin copolymer (component (B)) contained in the adhesive layer of the adhesive film of the present invention is 910 kg / m ³ or less. The pressure-sensitive adhesive film of the present invention having the pressure-sensitive adhesive layer containing such an ethylene-α-olefin copolymer (B) is less susceptible to fluctuations in pressure-sensitive adhesive force due to aging or heat treatment. The density of the component (B) is preferably 907 kg / m ³ or less, more preferably 905 kg / m ³ or less.

  The ethylene-α-olefin copolymer (component (B)) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is non-uniform from the viewpoint of making it difficult for fluctuations in the pressure-sensitive adhesive force due to aging or heat treatment of the resulting pressure-sensitive adhesive film. A copolymer polymerized by a system catalyst is preferable. The heterogeneous catalyst here is generally a Ziegler-Natta catalyst, which is composed of titanium and halogen, and is usually composed of chloride and preferably magnesium. Ziegler-Natta catalysts have a titanium compound that can be trivalent and / or tetravalent and an organoaluminum compound as a co-catalyst. A known catalyst can be used as the Ziegler-Natta catalyst.

  The molecular weight distribution of the ethylene-α-olefin copolymer (component (B)) is preferably 3 or more, more preferably 4 or more. By using an ethylene-α-olefin copolymer having such a molecular weight distribution as the component (B), the resulting adhesive film is less susceptible to fluctuations in adhesive strength due to aging or heat treatment.

  Examples of the polymerization method of the ethylene-α-olefin copolymer (component (B)) include a solution polymerization method, a slurry polymerization method, a high pressure polymerization method, a gas phase polymerization method, and the like, and preferably a gas phase polymerization method. The high pressure ion polymerization method.

  The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention comprises an ethylene-ethylenically unsaturated ester copolymer (A1) and / or a component (A) composed of an ethylene-α-olefin copolymer (A2) and an ethylene-α-olefin. It is formed from a resin composition containing a copolymer (component (B)). The ratio of the component (A) and the component (B) contained in the resin composition is such that the total of the component (A) and the component (B) is 100 parts by weight, and the component (A) is 70 to 99 parts by weight, and the component (B) 30 to 1 part by weight, preferably 80 to 97 parts by weight of component (A) and 20 to 3 parts by weight of component (B), more preferably 85 to 95 parts by weight of component (A), And 15 to 5 parts by weight of component (B). The pressure-sensitive adhesive film of the present invention having a pressure-sensitive adhesive layer formed from a resin composition having components (A) and (B) in the above range is less susceptible to fluctuations in pressure-sensitive adhesive force due to aging or heat treatment. Adhesive residue after the film is peeled off hardly occurs.

  In the present invention, a polyolefin resin other than the components (A) and (B) and a modified polyolefin other than the components (A) and (B) are optionally added to the resin composition forming the adhesive layer within the range that does not substantially impair the characteristics of the present invention. Other resins such as resin, rosin resin, polyterpene resin, synthetic petroleum resin, coumarone resin, phenol resin, xylene resin, styrene resin, isoprene resin can be added.

  Examples of the polyolefin resin include isotactic polypropylene, syndiotactic polypropylene, random type polypropylene including a comonomer, polypropylene such as block type polypropylene by multistage polymerization, and low density polyethylene (LDPE).

  The modified polyolefin resin is modified with a modifying compound such as maleic anhydride, dimethyl maleate, diethyl maleate, acrylic acid, methacrylic acid, tetrahydrophthalic acid, glycidyl methacrylate, hydroxyethyl methacrylate, etc. Polyolefin. The polyolefin resin to be modified here is not a known polyolefin, for example, an ethylene resin such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), isotactic polypropylene. , Syndiotactic polypropylene, random type polypropylene containing comonomer, block type polypropylene by multistage polymerization, poly (4-methyl-1-pentene), poly (1-butene) and the like.

  Examples of the rosin resin include natural rosin, polymerized rosin, partially hydrogenated rosin, fully hydrogenated rosin, esterified products of these rosins (for example, glycerin ester, pentaerythritol ester, ethylene glycol ester, methyl ester), Examples include rosin derivatives (eg, disproportionated rosin, fumarized rosin, and lime rosin).

  Examples of the polyterpene resin include homopolymers of cyclic terpenes such as α-pinene, β-pinene, and dipentene, copolymers of the above cyclic terpenes, the above cyclic terpenes, and phenols such as phenol and bisphenol. Copolymers (eg, terpene-phenol resins such as α-pinene-phenol resin, dipentene-phenol resin, terpene-bisphenol resin), the above cyclic terpenes and aromatics An aromatic modified terpene resin which is a copolymer with a monomer may be mentioned.

The synthetic petroleum resins, for example, C ₅ fraction naphtha cracked oil, C ₆ -C ₁₁ fraction, other olefinic fractions homopolymer or a copolymer, the water of these homopolymers and copolymers Examples thereof include aliphatic petroleum resins, aromatic petroleum resins, alicyclic petroleum resins, and aliphatic-alicyclic copolymers that are additives. Examples of the synthetic petroleum resin further include a copolymer of the naphtha cracked oil and the terpene, and a copolymer petroleum resin that is a hydrogenated product of the copolymer.

Preferred _{C 5} fraction of naphtha cracked oil, for example, isoprene, cyclopentadiene, 1,3-pentadiene, 2-methyl-1-butene, methylbutene such as 2-methyl-2-butene, 1-pentene, 2 -Pentenes such as pentene and dicyclopentadiene. Preferably, the C _{6 to} C ₁₁ fraction is methyl styrenes such as indene, styrene, o-vinyl toluene, m-vinyl toluene, p-vinyl toluene, α-methyl styrene, β-methyl styrene, methyl indene, ethyl indene. Vinyl xylene and propenylbenzene. Other preferred olefinic fractions are butene, hexene, heptene, octene, butadiene, and octadiene.

  Examples of the chroman resin include a chroman homopolymer or a chroman and indene copolymer.

  Examples of the phenolic resin include alkylphenol resins, alkylphenol-acetylene resins obtained by condensation of alkylphenol and acetylene, and modified products of these resins. Here, these phenolic resins may be any of a novolak type resin obtained by methylolation of phenol with an acid catalyst or a resol type resin obtained by methylolization with an alkali catalyst.

  Examples of the xylene-based resin include a xylene-formaldehyde resin composed of m-xylene and formaldehyde, and a modified resin obtained by adding and reacting a third component thereto.

  Examples of the styrene resin include a low molecular weight polymer of styrene, a copolymer of α-methylstyrene and vinyltoluene, a copolymer of styrene, acrylonitrile and indene, a copolymer of styrene and butadiene, and styrene and ethylene. Examples include butylene copolymers.

Examples of the isoprene-based resin include a resin obtained by copolymerizing a C ₁₀ alicyclic compound that is a dimerized form of isoprene and a C ₁₀ chain compound.

  In the present invention, an antioxidant, an anti-blocking agent, a lubricant, an antistatic agent, a weathering stabilizer, a resin composition forming an adhesive layer, if necessary, within a range that does not substantially impair the characteristics of the present invention. Additives such as pigments, processability improvers, and metal soaps may be added, and two or more of these additives may be used in combination. The base material layer may also contain these additives within a range that does not substantially impair the characteristics of the present invention.

  It does not specifically limit as a manufacturing method of the resin composition of the component (A) and component (B) which forms the adhesion layer of this invention, A well-known blend method is mentioned. Known blending methods include, for example, dry blending or melt blending of components (A) and (B), and other components such as additives as necessary. Various blenders such as a Henschel mixer and tumbler mixer can be used for the dry blending method, and various mixers such as a single screw extruder, a twin screw extruder, a Banbury mixer, and a hot roll can be used for the melt blending method. Can be used.

  Although it does not specifically limit as a material which forms the base material layer of the adhesive film of this invention, It is preferable to form from resin and it is preferable that a main component is an olefin type polymer. Examples of the olefin polymer include ethylene resins, propylene resins, and modified polyolefin resins.

  Examples of the ethylene resin include polyethylene resins such as high density polyethylene, medium density polyethylene, low density polyethylene, and linear low density polyethylene, ethylene-propylene copolymer resin, ethylene-butene copolymer resin, and ethylene. -Pentene copolymer resin, ethylene-hexene copolymer resin, ethylene-α-olefin copolymer such as ethylene-octene copolymer resin, ethylene-styrene copolymer resin, ethylene-cyclic olefin copolymer resin Examples of the propylene resin include a propylene homopolymer or a random or block copolymer of propylene and a small amount of an α-olefin and / or ethylene, and the modified polyolefin resin is, for example, anhydrous Maleic acid, dimethyl maleate, male Polyolefin modified with a modifying compound such as diethyl acid, acrylic acid, methacrylic acid, tetrahydrophthalic acid, glycidyl methacrylate, hydroxyethyl methacrylate. The polyolefin resin used here may be a known polyolefin. For example, the above-mentioned ethylene resin, isotactic polypropylene, syndiotactic polypropylene, random type polypropylene containing a comonomer, block type polypropylene by multistage polymerization, poly (4 -Methyl-1-pentene), poly (1-butene) and the like. Of these, ethylene resins and propylene resins are preferred.

The thickness of the base material layer in the pressure-sensitive adhesive film of the present invention can be appropriately selected within a range that does not impair the adhesiveness and the like, and is generally 3 to 500 μm, preferably 5 to 200 μm. The thickness of the pressure-sensitive adhesive layer can be appropriately selected within a range that does not impair the adhesiveness and the like, and is generally 1 to 100 μm, preferably 3 to 50 μm, and more preferably 5 to 30 μm. By setting the thickness of the base material layer within the above range, wrinkles and the like are less likely to occur when bonding to an adherend, and the handling of the adhesive film is improved.
The thickness of the adhesive layer in the adhesive film of this invention is 5-100 micrometers normally, Preferably it is 10-50 micrometers, More preferably, it is 10-20 micrometers.

  For the base material layer of the pressure-sensitive adhesive film of the present invention, for example, antifouling treatment, acid treatment, alkali treatment, primer treatment, anchor coating treatment, corona treatment, plasma treatment, ultraviolet treatment, Antistatic treatment can also be performed.

  The pressure-sensitive adhesive film of the present invention includes at least one base layer and at least one pressure-sensitive adhesive layer, and one surface layer is made of a resin composition containing a predetermined amount of component (A) and component (B). If so, the other layer configuration or the number of stacked layers is not particularly limited, but is usually about 2 to 7 layers. Examples of the layer structure of the pressure-sensitive adhesive film of the present invention include base material layer / adhesive layer, base material layer / adhesive layer / base material layer / adhesive layer, base material layer / adhesive layer / base material layer / adhesive layer, and the like. It is done.

  Examples of the method for producing the pressure-sensitive adhesive film of the present invention include a coextrusion molding method and a laminate molding method. As the co-extrusion molding method, for example, a base layer and an adhesive layer are extruded in a molten state and laminated by a known method such as a T-die molding method or an inflation molding method, and then a cooling means such as a cooling roll. The method of cooling by is mentioned. Further, as a lamination molding method, for example, a base material layer is prepared in advance by an extrusion molding method, and an adhesive layer is extruded in a molten state and laminated thereon, and then cooled by a cooling roll or the like. Although a method of cooling by means is mentioned, the co-extrusion method is preferred from the viewpoint of a wide variety of product designs. Moreover, the pressure-sensitive adhesive film of the present invention may be stretched in at least a uniaxial direction.

  When the pressure-sensitive adhesive film of the present invention is produced by extrusion molding, the resin temperature at the exit of the extruder is appropriately selected depending on the type of molding machine and the type and molecular weight of the resin used in each layer. ° C, preferably about 150 to 300 ° C. Moreover, the extruder and die used may be known ones and are not particularly limited.

  The pressure-sensitive adhesive film of the present invention is suitably used as a surface protective film. When the pressure-sensitive adhesive film of the present invention is used as a surface protective film, as its adherend, 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 product Examples of the optical member such as a polarizing plate, a retardation plate, a viewing angle widening plate, and a brightness enhancement plate used for a machine and a flat panel display such as an automobile body or a liquid crystal display at the time of manufacture can be exemplified. And suitable for a phase difference plate. Here, the polarizing plate, the retardation plate, the viewing angle widening plate, and the brightness enhancement plate include those referred to as a polarizing film, a retardation film, a viewing angle widening film, and a brightness enhancement film, respectively. Since the pressure-sensitive adhesive film of the present invention is excellent in transparency, it can be easily inspected while being bonded to an adherend, and thus is particularly suitable as a surface protective film for optical members.

The following examples further illustrate the present invention.
[I] Measuring method The physical properties were measured as follows.
(1) tan δ
The tan δ of the component (A) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is obtained by pressing the component (A) to produce a measurement sheet having a width of 3 mm and a thickness of 0.3 mm. Using a viscoelasticity measuring device DMS200, the distance between chucks was 20 mm, the heating rate was 5 ° C./min, and the frequency was 5 Hz, and the value at 23 ° C. was read.
(2) Melt flow rate (unit: g / 10 min)
The melt flow rate of component (A) and component (B) contained in the adhesive layer of the adhesive film of the present invention was measured according to JIS K 7210 at a test temperature of 190 ° C. and a test load of 21.18N.
(3) Heptane extraction amount (unit: wt%)
The amount of heptane extracted from the ethylene-α-olefin copolymer of component (A) and component (B) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention was obtained by immersing 100 g of pellets in 250 cc of heptane at 30 ° C. for 9 hours. Then, it filtered by suction with the glass filter and measured and calculated | required the quantity extracted to the heptane solution.
(4) Density (Unit: kg / m ³ )
The density of the ethylene-α-olefin copolymer of component (A) and component (B) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention is measured according to the method defined in method A of JIS K7112-1980. did. In addition, the measurement sample piece was annealed according to the method of low density polyethylene described in JIS K6760-1995 and used for measurement.
(5) Molecular weight distribution The molecular weight distribution of the component (B) contained in the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention was determined by measurement under the following conditions using a gel permeation chromatograph (GPC) method.
Equipment: 150C ALC / GPC manufactured by Waters
Column: Shodex Packed Column A-80M manufactured by Showa Denko KK Temperature: 140 ° C
Solvent: o-dichlorobenzene elution solvent flow rate: 1.0 ml / min Sample concentration: 1 mg / ml
Measurement injection volume: 400 μl
Molecular weight standard substance: Standard polystyrene detector: Differential refraction (6) Monomer unit content derived from ethylenically unsaturated ester in component (A1) <In the case of monomer unit content derived from methyl methacrylate>
FT / IR-7300 manufactured by JASCO Corporation was used as an apparatus, and it was determined from the following formula 1 based on the infrared absorption spectrum analysis method of a sheet having a thickness of 0.3 mm.
MMA = {4.1 × log (I ₀ /I)/t}−5.3 Equation 1

In Formula 1, MMA is the content (% by weight) of methyl methacrylate monomer unit, I is the transmitted light intensity at a frequency of 3448 cm ⁻¹ , I ₀ is the incident light intensity at a frequency of 3448 cm ⁻¹ , and t is a measurement sample. The sheet thickness (cm) is shown. The baseline for determining I ₀ was 3510-3310 cm ⁻¹ .
<In the case of monomer unit content derived from vinyl acetate>
It measured according to JIS K6730-1981.
(7) Initial adhesive strength (unit: N / 25mm width)
In accordance with JIS-K-Z0237, in a temperature-controlled room at 23 ° C., the pressure-sensitive adhesive film in which the base material layer / the pressure-sensitive adhesive layer is laminated is cut into a strip shape (width 25 mm, length 150 mm), and is 50 mm wide and 150 mm long. On the polarizing plate cut out, the pasting roller was reciprocated once at a pasting speed of 300 mm / min to cause pressure bonding, and this was left at 23 ° C. for 30 minutes. In an atmosphere of 23 ° C., the force required to peel the adhesive film from the polarizing plate by the 180 ° peeling method under the condition of a peeling speed of 300 mm / min was measured by an autograph AGS-500D manufactured by Shimadzu Corporation. This was defined as initial adhesive strength.
(8) Adhesive strength after heat treatment (unit: N / 25mm width)
In accordance with JIS-K-Z0237, in a temperature-controlled room at 23 ° C., the pressure-sensitive adhesive film in which the base material layer / the pressure-sensitive adhesive layer is laminated is cut into a strip shape (width 25 mm, length 150 mm), and is 50 mm wide and 150 mm long. On the polarizing plate cut out, a pasting roller was reciprocated once at a pasting speed of 300 mm / min to cause pressure bonding, and this was heat-treated at 80 ° C. for 3 hours and further left at 23 ° C. for 30 minutes. In an atmosphere of 23 ° C., the force required to peel the adhesive film from the polarizing plate by the 180 ° peeling method under the condition of a peeling speed of 300 mm / min was measured by an autograph AGS-500D manufactured by Shimadzu Corporation. This was taken as the adhesive strength after heat treatment.
(9) Fluctuation of adhesive strength before and after heat treatment The initial adhesive strength and the value of the adhesive strength after heat treatment (= adhesive strength after heat treatment / initial adhesive strength) were taken as the adhesive force increase ratio. The closer this value is to 1, the less variation in adhesive strength before and after heat treatment.
(10) Adhesive residue after heat treatment In a thermostatic chamber at 23 ° C., the adhesive film in which the base material layer / adhesive layer is laminated is cut into a strip shape (25 mm in width, 150 mm in length) to a size of 50 mm in width and 150 mm in length. On the cut-out polarizing plate, the bonding roller was reciprocated once at a bonding speed of 300 mm / min to be pressure-bonded, heat-treated at 80 ° C. for 3 hours, and further left at 23 ° C. for 30 minutes. The surface of the polarizing plate of the sample obtained by peeling the adhesive film from the polarizing plate by a 180 ° peeling method was visually observed in a 23 ° C. atmosphere under a peeling speed of 300 mm / min, and evaluated as follows.
X: Adhesive residue is recognized.
○: No adhesive residue is observed.
(11) Transparency (unit:%)
Using the obtained adhesive film, the haze value was measured according to JIS K 7105. The smaller this value, the higher the transparency.

Example 1
As the resin for the adhesive layer, an ethylene-methyl methacrylate copolymer (trade name: ACLIFT WH303, manufactured by Sumitomo Chemical Co., Ltd., MFR = 7 g / 10 min, tan δ = 0.09 at 23 ° C., methacrylic) 95 parts by weight of methyl acid monomer unit content = 18 wt%) and ethylene-butene-1 copolymer (trade name: Excellen VL VL700, manufactured by Sumitomo Chemical Co., Ltd., MFR: 10 g / 10 min) as component (B) , Density: 905 Kg / m ³ , heptane extract amount = 2.0 wt%, molecular weight distribution = 4.6, heterogeneous catalyst) 5 parts by weight was melt kneaded at 230 ° C. in advance with a single screw extruder, and component (A) And a mixture (AB) of the component (B) was obtained. The adhesive films for evaluation of the above (7), (8) and (9) were produced according to the following method.
[Create adhesive film]
A polyethylene-based resin (trade name: L211, manufactured by Sumitomo Chemical Co., Ltd., MFR = 2 g / 10 min) is used as the base layer resin, and the above mixture (AB) is used as the adhesive layer resin. Using a 30 mmφ type 2 double-layer T die film molding machine (T die width 250 mm, lip opening 0.9 mm) manufactured by Plastic Co., Ltd., a die temperature 190 ° C., a cooling roll 30 ° C., a take-up speed 6.0 m / Minutes, each layer had a thickness of 10 μm, a base layer of 50 μm, and a total film thickness of 60 μm.
[Evaluation of the obtained film]
The obtained film was bonded to a polarizing plate and evaluated. The results are shown in Table 1.

Example 2
An adhesive film was prepared and evaluated in the same manner as in Example 1 except that 90 parts by weight of component (A) and 10 parts by weight of component (B) were used. The results are shown in Table 1.

Example 3
An adhesive film was prepared and evaluated in the same manner as in Example 1 except that 70 parts by weight of the component (A) in Example 1 and 30 parts by weight of the component (B) were used. The results are shown in Table 1.

Example 4
As the resin for the adhesive layer, an ethylene-vinyl acetate copolymer (trade name: Evaate H3011, manufactured by Sumitomo Chemical Co., Ltd., MFR = 7 g / 10 min, tan δ = 0.15 at 23 ° C., vinyl acetate A monomer unit content = 15 wt% was prepared and evaluated in the same manner as in Example 1 except that 90 parts by weight were used. The results are shown in Table 1.

Example 5
As resin of the adhesive layer, component (B) ethylene-butene-1 copolymer (trade name: Excellen VL EUL731, manufactured by Sumitomo Chemical Co., Ltd., MFR: 10 g / 10 min, density: 895 Kg / m ³ , heptane extract amount = 6.1 wt%, molecular weight distribution = 4.0, heterogeneous catalyst) was used and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6
As resin of the adhesion layer, ethylene-hexene-1 copolymer (trade name: Excellen FX CX4008, manufactured by Sumitomo Chemical Co., Ltd., MFR: 8 g / 10 min, heptane extract amount = 0.8 wt%, as component (A) A pressure-sensitive adhesive film was prepared and evaluated in the same manner as in Example 1 except that the density was 880 kg / m ³ , tan δ at 23 ° C .: 0.02, and homogeneous catalyst). The results are shown in Table 2.

Example 7
As an adhesive layer resin, an ethylene-hexene-1 copolymer polymerized by a homogeneous catalyst as component (A) (trade name: Excellen FX CX8008, manufactured by Sumitomo Chemical Co., Ltd., MFR: 14 g / 10 min, heptane Extraction amount = 0.5 wt%, density: 894 Kg / m ³ , tan δ at 23 ° C .: 0.03, homogeneous catalyst) Except for 90 parts by weight, an adhesive film was prepared and evaluated in the same manner as in Example 1. went. The results are shown in Table 2.

Comparative Example 1
As an adhesive layer resin, ethylene-methyl methacrylate copolymer (trade name: ACRIFTH WH303, manufactured by Sumitomo Chemical Co., Ltd., MFR = 7 g / 10 min, tan δ = 0.09 at 23 ° C., methacrylic) It was prepared and evaluated in the same manner as in Example 1 except that only 100 parts by weight of methyl acid monomer unit content = 18 wt% was used. The results are shown in Table 3.

Comparative Example 2
As an adhesive layer resin, an ethylene-butene-1 copolymer (trade name: Excellen VL VL700, manufactured by Sumitomo Chemical Co., Ltd., MFR: 10 g / 10 min, density: 903 Kg / m ³ , heptane extraction as component (B) An amount of 2.0 wt%, a heterogeneous catalyst) was prepared and evaluated in the same manner as in Example 1 except that only 100 parts by weight was used. The results are shown in Table 3.

Comparative Example 3
As resin of the adhesive layer, component (B) ethylene-butene-1 copolymer (trade name: Excellen VL VL200, manufactured by Sumitomo Chemical Co., Ltd., MFR: 2 g / 10 min, density: 900 Kg / m ³ , heptane extract amount = 2.5 wt%, heterogeneous catalyst) was used and evaluated in the same manner as in Example 1. The results are shown in Table 3.

Comparative Example 4
As resin of the adhesive layer, component (B) ethylene-hexene-1 copolymer (trade name: Excellen FX CX4008, manufactured by Sumitomo Chemical Co., Ltd., MFR: 8 g / 10 min, density: 880 Kg / m ³ , heptane extract amount = 0.8 wt%, homogeneous catalyst) was used and evaluated in the same manner as in Example 1. The results are shown in Table 3.

Claims (6)

A pressure-sensitive adhesive film in which a pressure-sensitive adhesive layer and a base material layer are laminated, wherein the pressure-sensitive adhesive layer contains 70 to 99 parts by weight of the following component (A) and 30 to 1 part by weight of component (B) ( However, the pressure-sensitive adhesive film formed from 100 parts by weight of the sum of the component (A) and the component (B).
Component (A): ethylene-ethylenically unsaturated ester copolymer (A1) that satisfies the following conditions (a-1) and (a-2) and / or the following conditions (a-1)-(a-3) -Α-olefin copolymer (A2) satisfying all the requirements
(A-1): tan δ at 23 ° C. is 0.01 or more (a-2): Melt flow rate (MFR) is 1 to 50 g / 10 minutes (a-3): Heptane extract amount is 1.0 wt% or less (B): an ethylene-α-olefin copolymer that satisfies all the following conditions (b-1)-(b-3) (b-1): a melt flow rate (MFR) of 3 g or more / 10 minutes (b-2) ): Heptane extraction amount is 1.5 wt% or more and 7.0 wt% or less (b-3): density is 910 kg / m ³ or less   The pressure-sensitive adhesive film according to claim 1, wherein the ethylene-α-olefin copolymer (A2) is an ethylene-α-olefin copolymer polymerized by a homogeneous catalyst.   The pressure-sensitive adhesive film according to claim 1, wherein the component (B) is an ethylene-α-olefin copolymer polymerized by a heterogeneous catalyst.   The pressure-sensitive adhesive film according to claim 1, wherein a main component forming the base material layer is an olefin polymer.   The pressure-sensitive adhesive film according to claim 1, obtained by co-extrusion of a base material layer and a pressure-sensitive adhesive layer.   The pressure-sensitive adhesive film according to claim 1, which is a surface protective film for optical members.