JP4855093B2 - Surface protective film substrate, surface protective adhesive film, and method for producing the same - Google Patents

Description

  The present invention relates to a film substrate for surface protection. Moreover, this invention relates to the adhesive film for surface protection, and its manufacturing method.

  The pressure-sensitive adhesive film for surface protection of the present invention can be applied for surface protection of various substances. For example, a metal plate, a painted plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate, a polarizing plate, etc. When transporting, processing or curing an optical member such as a film or a liquid crystal panel, an electronic member, etc., it is used for affixing and protecting the surface of these members. In particular, it is useful as an adhesive film for surface protection of metal plates such as stainless steel plates, aluminum plates, and steel plates, and in particular, it is necessary to confirm the orientation of the surface of the adherend, such as the stretching direction and flow lines of the metal plate. It is suitable for protection in a case where

  Conventionally, when processing or transporting a metal plate such as a stainless steel plate, an aluminum plate, or a steel plate, a surface protective film is temporarily attached to prevent the surface of the metal plate from being scratched. We are trying to protect it. As the surface protective film of such a metal plate, an adhesive film (surface protective adhesive film) provided with an adhesive layer on one side of a base film is used. Conventionally, the adhesive film of a vinyl chloride base material has been the mainstream as the base material of such an adhesive film. However, in recent years, polyvinyl chloride (vinyl chloride) has been promoted from the viewpoint of environmental protection, and application of a polyolefin-based substrate as a substrate replacing the vinyl chloride-based substrate is being studied.

  However, as a first problem, the stretch direction is determined when processing the hairline or the like on the surface of the metal plate, and when using a polyolefin-based substrate, the adherend after pasting the adhesive film The direction of the flow line of the metal plate etc. cannot be confirmed, and when the metal plate as the adherend is processed and cut, the problem is that the protective film must be peeled off in order to confirm the above direction there were. In addition, as a second problem, when a polyolefin-based substrate is used, the back surface of the film is less slidable than a protective film using a conventional vinyl chloride-based substrate. When affixed metal plates are stacked and stored, the back side of the film and the heavy metal plate cause blocking and slipperiness is reduced, making it difficult to pull out the gold bent plate and making it easier to work than PVC adhesive films. It turns out that the problem gets worse.

  For the first problem described above, as a method for facilitating confirmation of the direction of the adherend, a method for printing on the protective film and a method for improving the transparency of the protective film have been studied. (For example, refer to Patent Document 1). However, the method using the printing process is not preferable from the viewpoint of productivity and cost because the number of processing processes increases. Further, for example, even when the transparency of the base material is improved so that the hue and pattern of the protected body (adhered body) can be identified as in the invention described in Patent Document 1, the above-mentioned second The problem of back-slip, which is the problem of, has not been solved yet. Furthermore, with the conventional method of improving transparency, naturally the protective film cannot be colored, and the material manufacturer uses the protective film surface for design and advertisement in order to differentiate their products and to advertise. I couldn't.

JP 2002-97430 A

  Accordingly, an object of the present invention is to solve the above-mentioned problems in the conventional surface protective film, the surface (flow line) of the surface protective adhesive film can be easily understood, and the surface on which the back side of the film is improved is improved. It is providing the adhesive film for protection, and its manufacturing method.

  Moreover, the objective of this invention is providing the film base material for surface protection used for the said adhesive film for surface protection.

  In order to achieve the above object, the present inventors have intensively studied the components of the back surface treatment layer. As a result, they have found the following surface protective film base material and have completed the present invention.

That is, the film substrate for surface protection of the present invention is
A film substrate for surface protection comprising at least one base layer (I) comprising a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof, wherein the base layer (I) Ethylene vinyl alcohol containing 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or a derivative thereof with respect to 100 parts by weight of the polyolefin resin, and dispersed in the base material layer (I) The major axis average length ( _LMD ) of the microregion of the copolymer and / or derivative thereof is 3.5 μm or more and the content area ratio of the microregion is 4% or more.

The surface protective film substrate of the present invention contains a specific amount of an ethylene vinyl alcohol copolymer and / or a derivative thereof in the substrate layer (I), so that it is uniformly dispersed with a small region in the polyolefin resin. It is presumed that streaks are formed in the stretching direction of the film, so that the flow lines can be seen at a glance, and the surface irregularities generated with the formation of the streaks improve the slipperiness. In addition, as long as the relative direction of both can be discriminate | determined, the extending | stretching direction etc. of the metal which is a to-be-adhered body, and the flow line of the surface protection film base material may be bonded in the same direction or another direction. In addition, the shape of the minute region has a major axis average length (L _MD ) of 3.5 μm or more and a content area ratio of the minute region of 4% or more. Is also preferable. Furthermore, since the present invention does not attempt to determine the orientation and direction of the adherend by the conventional improvement in transparency, the streaks (flow lines) can be determined by visual observation or surface tactile sensation. The base material layer and the base material surface can be colored and decorated. Therefore, it is possible to add a design effect and an advertising usage.

In the film substrate for surface protection, it is preferable that the ratio (L _MD / L _TD ) of the major axis average length (L _MD ) and minor axis average length (L _TD ) of the microregion is 2 or more.

  In the present invention, when a plurality of the base material layers (I) and other base material layers (II) are laminated, the base material layer (I) is used for the surface protection. It is necessary to be provided in the outermost layer of the film substrate.

  Moreover, in this invention, it is preferable that the 10-point average surface roughness (Rz) of the said base material layer (I) is 2.0 micrometers or more. In addition, the 10-point average surface roughness (Rz) in the present invention refers to a value measured in accordance with JIS-B0651.

  Furthermore, in the present invention, the base material layer (I) is a fine particle having a particle size of 0.5 to 100 parts by weight based on 100 parts by weight of a polyolefin mixture composed of the polyolefin resin and the ethylene vinyl alcohol copolymer and / or a derivative thereof. It is preferable to contain 10 parts by weight. By using the fine particles, the slipperiness of the back surface of the film can be improved and the workability can be improved more reliably.

  In the present invention, the fine particles are preferably synthetic zeolite and / or synthetic silica. The average particle size of the fine particles is preferably 1 to 20 μm. In particular, when the average particle diameter of the fine particles is larger than the thickness of the base material layer (I), the slipperiness is very good.

  On the other hand, the surface-protective pressure-sensitive adhesive film of the present invention is characterized by having a pressure-sensitive adhesive layer on one surface of any one of the above-mentioned surface-protective film substrates. In the case where the surface protective film base material is formed by laminating a plurality of the base material layer (I) and other base material layers (II), the base material layer (I) is the surface protective film base. A pressure-sensitive adhesive layer is provided on the surface of the outermost layer opposite to the base material layer (I) so as to be the outermost layer of the material (the outermost surface of the pressure-sensitive adhesive film). Since the surface protective adhesive film of the present invention includes the surface protective film substrate having the above-described functions, the direction (flow line) of the surface protective adhesive film and the stretching direction of the metal plate as the adherend can be easily understood. In addition, the slidability of the back surface of the film can be improved and workability can be improved.

  Moreover, in the said surface protection adhesive film, it is preferable that the said film base material and the said adhesive layer are integrally formed by coextrusion molding.

  In addition, the adhesive film for surface protection in this invention means the film which has an adhesive layer used in order to protect the surface of a to-be-adhered body, and includes a sheet form and a tape form thing.

On the other hand, the method for producing a surface protective pressure-sensitive adhesive film of the present invention is a method for producing a surface protective pressure-sensitive adhesive film comprising a step of integrally forming a film substrate and a pressure-sensitive adhesive layer by coextrusion molding,
The film base is provided with at least one base layer (I) made of a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof, and the base layer (I) is An ethylene vinyl alcohol copolymer containing 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or its derivative with respect to 100 parts by weight of a polyolefin resin and dispersed in the base material layer (I). And / or the length average length ( _LMD ) of the microregion of the derivative thereof is 3.5 μm or more and the content area ratio of the microregion is 4% or more.

  By using the production method of the present invention, the direction of the adhesive film for surface protection (flow line), the stretching direction of the metal plate as the adherend, etc. can be easily understood, and the surface protection with improved slipping on the back side of the film The adhesive film for use can be easily obtained by omitting complicated processes such as printing.

  Hereinafter, embodiments of the present invention will be described in detail.

The film substrate for surface protection of the present invention is
A film substrate for surface protection comprising at least one base layer (I) comprising a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof, wherein the base layer (I) Ethylene vinyl alcohol containing 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or a derivative thereof with respect to 100 parts by weight of the polyolefin resin, and dispersed in the base material layer (I) The major axis average length ( _LMD ) of the microregion of the copolymer and / or derivative thereof is 3.5 μm or more, and the content area ratio of the microregion is 4% or more.

  The film substrate for surface protection of the present invention (hereinafter sometimes referred to as “substrate film”) is a film substrate in which at least one layer of the substrate layer (I) is provided. The film base material may be composed of the base material layer (I), or may be a laminate of a plurality of the base material layers (I) and other base material layers (II). . Moreover, when the said base material layer (I) and other base material layers (II) are laminated | stacked in multiple numbers, the said base material layer (I) is an outermost layer of the said surface protective film base material. It is necessary to be provided.

The base material layer (I) of the present invention is made of a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof. The base layer (I) contains 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or a derivative thereof with respect to 100 parts by weight of the polyolefin-based resin, and the base layer (I) The average length (L _MD ) of the microregion of the ethylene vinyl alcohol copolymer and / or derivative thereof dispersed in the microregion is 3.5 μm or more and the content area ratio of the microregion is 4% or more. And

  The base material layer (I) of the present invention is not particularly limited as long as it is a polyolefin resin that can disperse the ethylene vinyl alcohol copolymer and / or its derivative and can be formed into a sheet or film. It is preferable that the polyolefin resin has heat resistance and solvent resistance and has flexibility. When the base material layer has flexibility, it can be wound into a roll and various processes can be appropriately performed.

  Examples of the polyolefin resin used as a constituent component of the base material layer (I) include polymers containing α-olefins having 2 to 12 carbon atoms, for example, α-olefins such as ethylene, propylene and 1-butene. Homopolymer or olefin (co) polymer, ethylene / olefin copolymer, polyethylene resin, propylene or propylene resin composed of propylene and ethylene components, ethylene vinyl acetate copolymer, and ethylene / polar vinyl copolymer For example, coalescence. These polymers may be used alone or in combination of two or more.

  More specifically, as the polyolefin-based resin, for example, low density polyethylene, linear low density polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer, Ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 4-methyl-1-pentene copolymer, ethylene / 1-octene copolymer, ethylene / methyl acrylate copolymer, ethylene -Methyl methacrylate copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer and the like.

  Moreover, base material layer (I) may be used by a single layer, and may be comprised from two or more layers. In particular, when the base material layer (I) is composed of two or more layers, each adjacent layer can form a strong bond with each other by melt coextrusion. Preferably there is.

  The content of the olefinic resin in the base material layer (I) is usually 50 in the matrix resin of the base material layer (I) (that is, the base polymer excluding the ethylene vinyl alcohol copolymer and / or its derivative). It is about -100 weight%, It is preferable that it is about 60-100 weight%, and it is more preferable that it is 70-100 weight%.

  In the present invention, the base material layer (I) may appropriately contain various known additives generally used for this type of film base material to the extent that the effects of the present invention are not impaired. For example, powders such as silane coupling agents, tackifiers, colorants, pigments, dyes, surfactants, plasticizers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers UV absorbers, polymerization inhibitors, heat stabilizers, antistatic agents, inorganic or organic fillers, metal powders, particles, foils and the like can be added as appropriate according to the intended use.

  In addition, the surface of the base material layer (I) may be subjected to easy attachment treatment such as corona treatment or plasma treatment.

  Furthermore, the thickness of the base material layer (I) is usually about 30 to 200 μm, preferably about 50 to 150 μm when the surface protecting film base material is made of the base material layer (I). Moreover, when the said base material for film | membrane for surface protection has laminated | stacked two or more said base material layers (I) and other base material layers (II), it is provided in the outermost layer of the said film base material for surface protection. The thickness of the substrate layer (I) is usually 0.5 to 80 μm, preferably about 1 to 40 μm.

  Moreover, the said base material for film | membrane for surface protection may be a thing in which the said base material layer (I) and other base material layers (II) are laminated | stacked two or more.

  The base material layer (II) of the present invention is not particularly limited as long as it is a resin that can be formed into a sheet shape or a film shape, and is a polyolefin-based resin having heat resistance and solvent resistance and flexibility. It is preferable. When the base material layer has flexibility, it can be wound into a roll and various processes can be appropriately performed.

  Examples of the component (polymer) of the base material layer (II) include polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer, ethylene / 1- Polyolefin film such as butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyester film such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyacrylate Examples include films, polystyrene films, nylon 6, nylon 6,6, polyamide films such as partially aromatic polyamide, polyvinyl chloride films, polyvinylidene chloride films, and polycarbonate films. Of these, polyethylene, polypropylene and the like are preferable. These polymers may be used alone or in combination of two or more.

  In the present invention, the base material layer (II) may appropriately contain various known additives generally used for this type of film base material to the extent that the effects of the present invention are not impaired. For example, powders such as silane coupling agents, tackifiers, colorants, pigments, dyes, surfactants, plasticizers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers UV absorbers, polymerization inhibitors, heat stabilizers, antistatic agents, inorganic or organic fillers, metal powders, particles, foils and the like can be added as appropriate according to the intended use.

  In addition, the surface of the base material layer (II) may be subjected to easy attachment treatment such as corona treatment and plasma treatment.

  Furthermore, the thickness of the base material layer (II) is usually about 10 to 200 μm, preferably about 30 to 150 μm.

  The thickness of the entire surface protecting film substrate is usually about 20 to 300 μm, preferably about 20 to 250 μm, more preferably about 40 to 200 μm. If the substrate layer is less than 20 μm, the substrate may be torn or torn during peeling, and if it exceeds 300 μm, the stiffness of the substrate becomes large, and floating or the like tends to occur after sticking.

In the present invention, the base layer (I) is made of a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof. The base material layer (I) contains 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or a derivative thereof with respect to 100 parts by weight of the polyolefin resin, and the base material layer (I) That the average length (L _MD ) of the microregions of the ethylene vinyl alcohol copolymer and / or derivative thereof dispersed therein is 3.5 μm or more and the content area ratio of the microregions is 4% or more. Features.

  The ethylene vinyl alcohol copolymer and / or derivative thereof of the present invention is a copolymer of ethylene and vinyl alcohol, as well as functional group conversion of the main chain, side chain, and terminal of the ethylene vinyl alcohol copolymer, or other molecules. The derivative is not particularly limited as long as it is a derivative subjected to molecular modification such as addition.

  Regarding the degree of polymerization of the ethylene / vinyl alcohol copolymer and / or derivative, it exhibits an appropriate surface migration, but when the adhesive layer is directly provided on the base material layer (I) or when it is stored in a roll form, etc. In that the degree of polymerization is 300 to 3,000, the degree of polymerization is more preferably 400 to 3,000, and the degree of polymerization is 500 to 2,500. Some are more preferred. The degree of polymerization is a value calculated from the number average molecular weight obtained by polystyrene conversion by GPC (gel permeation chromatography).

  Further, the content of the ethylene structural unit is preferably 5 to 90 mol% in view of good compatibility (dispersibility) with the resin (matrix resin) constituting the base material layer (I). More preferably, it is -80 mol%, and it is further more preferable that it is 20-70 mol%.

  Specific examples of the ethylene vinyl alcohol copolymer derivative include, for example, those obtained by molecularly modifying a hydroxyl group of a vinyl alcohol unit with an acid anhydride or an isocyanate compound.

  Examples of the isocyanate compounds include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, aliphatic isocyanates such as hexamethylene diisocyanate, octyl isocyanate, nonyl isocyanate, decyl isocyanate, undecyl isocyanate, and dodecyl. Long chain alkyl isocyanates such as isocyanate, stearyl isocyanate, lauryl isocyanate and the like can be mentioned. These compounds may be used alone or in combination of two or more.

  Moreover, in the said base material layer (I), although 3-20 weight part of ethylene vinyl alcohol copolymers and / or its derivative are contained with respect to 100 weight part of said polyolefin resin, 3-15 weight part It is preferably contained, more preferably 4 to 14 parts by weight, and even more preferably 6 to 13 parts by weight. If it is less than 3 parts by weight, it is difficult to discriminate muscles (flow lines) with the naked eye, while if it exceeds 20 parts by weight, film forming may be difficult.

In the present invention, the major axis average length (L _MD ) of the microregion of the ethylene vinyl alcohol copolymer and / or derivative thereof dispersed in the base material layer (I) is 3.5 μm or more, and The content area ratio of the minute region is 4% or more.

  In addition, the said micro area | region in this invention is the said ethylene in the state by which the said ethylene vinyl alcohol copolymer and / or its derivative are microphase-separated in the polyolefin resin which is a matrix resin of a base material layer (I). An assembly region (domain) of a vinyl alcohol copolymer and / or a derivative thereof. By including a stretching treatment or a stretching step when manufacturing the surface protective film substrate (or surface protective adhesive film), the microregion becomes an elliptical shape (elliptical sphere) flattened in the stretching direction. The unevenness and streaks (flow lines) on the surface of the film substrate, which is a feature of the present invention, are expressed by the region, the orientation of each minute region, and the aggregate form thereof.

Moreover, in this invention, the length of the extending | stretching direction which performed the extending | stretching process at the time of film base-material (or adhesive film for surface protection) manufacture becomes a major axis average length ( _LMD ) of the said micro area | region normally, and is the extending | stretching direction The length in the vertical direction is usually the average length of the major axis (L _TD ) of the minute region.

  Moreover, the content area ratio of the micro area | region in this invention means the area ratio (%) of the said micro area | region in the cross section of base material layer (I).

In addition, the major axis average length ( _LMD ), minor axis average length ( _LTD ), and content area ratio of the microregions are those calculated by cross-sectional observation with a scanning electron microscope (SEM). In calculating the length, an image observed at a magnification of 300 to 10,000 is usually used. For example, the image is observed at a magnification of 1,000, 3,000, or 5,000. It is preferable to calculate using the obtained image.

In the present invention, the major axis average length ( _LMD ) of the microregion is 3.5 μm or more, preferably 4 μm or more, more preferably 6 μm or more, and further preferably 8 μm or more. preferable.

  In the present invention, the content area ratio of the microregion is 4% or more, preferably 8% or more, more preferably 11% or more, and further preferably 15% or more. .

Furthermore, in the present invention, the ratio (L _MD / L _TD ) of the major axis average length (L _MD ) and minor axis average length (L _TD ) of the microregion is preferably 2 or more, and is 3 or more. Is more preferably 4 or more, still more preferably 5 or more.

Incidentally, the major axis average length of the minute region _{(L MD)} and the ratio _(L MD _/ L _TD) of the major axis average length of the minute region _{(L MD)} and minor axis average length _{(L TD)} is the manufacturing process Fine adjustment is usually possible by the stretching step (stretching treatment).

  In the present invention, a mixture of the polyolefin resin and the ethylene vinyl alcohol copolymer and / or a derivative thereof is referred to as a polyolefin mixture.

  In the present invention, the ten-point average surface roughness (Rz) of the base material layer (I) is preferably 2.0 μm or more, more preferably 3.0 μm or more, and 4.0 μm or more. More preferably it is.

The ten-point average surface roughness (Rz) is a value measured according to JIS-B0651, and specifically, a value calculated as follows. That is, as shown in the following equation (I), a reference length l is extracted from the roughness curve in the direction of the average line, and the altitude of the highest peak from the highest peak to the fifth peak (from the average line of this extracted part) The sum of the average of the absolute values of Yp) and the average of the absolute values of the altitudes (Yv) of the bottom valley from the lowest valley bottom to the fifth is called ten-point average surface roughness (Rz).
Formula (I):
Rz = [| Yp1 + Yp2 + Yp3 + Yp4 + Yp5 | + | Yv1 + Yv2 + Yv3 + Yv4 + Yv5 |] / 5

  Furthermore, in the present invention, it is preferable that the base material layer (I) further contains fine particles. By using the fine particles, the slipperiness of the back surface of the film can be improved and the workability can be improved more reliably.

  In the present invention, the base material layer (I) preferably further contains 0.5 to 10 parts by weight, more preferably 1 to 8 parts by weight, with respect to 100 parts by weight of the polyolefin mixture. More preferably, it is contained in an amount of 1.5 to 5 parts by weight. A larger amount of addition is preferable for the slipperiness of the back surface of the film, but if it is too much, film forming tends to be difficult.

  Examples of the fine particles include synthetic zeolite, natural zeolite, aluminum silicate porous ore, synthetic silica, natural silica, acrylic crosslinked particles, styrene crosslinked particles, polymer beads, crosslinked PMMA (polymethylmethacrylate), ultra-high Examples thereof include molecular weight PE (polyethylene), talc, hydrous magnesium silicate and surface treated products thereof, and other organic fillers and inorganic fillers. Among these, it is preferable to use synthetic zeolite and / or synthetic silica as the fine particles. These fine particles may be used alone or in combination of two or more.

  The average particle size (average particle size) of the fine particles is preferably 1 to 20 μm, more preferably 3 to 15 μm, and further preferably 4 to 13 μm. In particular, when the average particle diameter of the fine particles is larger than the thickness of the base material layer (I), the slipperiness is very good.

  The film substrate for surface protection of the present invention has the configuration as described above.

  On the other hand, the pressure-sensitive adhesive film for surface protection of the present invention is characterized in that a pressure-sensitive adhesive layer is provided on one side of the above-mentioned surface protective film substrate. In the case where the surface protective film base material is formed by laminating a plurality of the base material layer (I) and other base material layers (II), the base material layer (I) is the surface protective film base. A pressure-sensitive adhesive layer is provided on the surface of the outermost layer opposite to the base material layer (I) so as to be the outermost layer of the material. Since the surface protective adhesive film of the present invention includes the surface protective film substrate having the above-described functions, the direction (flow line) of the surface protective adhesive film and the stretching direction of the metal plate as the adherend can be easily understood. In addition, the slidability of the back surface of the film can be improved and workability can be improved.

  The components of the pressure-sensitive adhesive layer in the present invention are not particularly limited, and are usually pressure-sensitive pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, polyvinyl ether-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and natural rubber and / or synthetic. Examples thereof include an adhesive having rubber as a main component (base polymer). These pressure-sensitive adhesives may be used alone or in combination of two or more.

  Examples of the acrylic pressure-sensitive adhesive include polyacrylic acid esters such as polyacrylic acid, polymethyl acrylate, and polyethyl acrylate, polymethacrylic acid esters such as polyethyl methacrylate and polybutyl methacrylate, and polyacrylonitrile. The thing which has a main component is mention | raise | lifted.

  Examples of the polyvinyl ether-based pressure-sensitive adhesive include those mainly composed of polyvinyl ethyl ether, polybutyl isobutyl ether, and the like.

  Examples of the silicone pressure-sensitive adhesive include those containing dimethylpolysiloxane as a main component.

  Examples of the pressure-sensitive adhesive mainly composed of the synthetic rubber include olefin copolymers, aromatic group-containing olefin / diene copolymers or hydrogenated products thereof, and mixtures thereof.

  Examples of the olefin copolymer include an α-olefin copolymer containing at least two α-olefins selected from α-olefins having 2 to 12 carbon atoms as main components.

  Examples of the α-olefin having 2 to 12 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene. Examples include 3-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene and the like.

  Among the α-olefin copolymers composed of a combination of these α-olefins, there is a pressure-sensitive adhesive mainly composed of a copolymer composed of three components of propylene, 1-butene and an α-olefin having 5 to 12 carbon atoms. preferable.

  In particular, a pressure-sensitive adhesive having a main component (base polymer) of a copolymer having a composition of 10 to 85 mol% of propylene, 3 to 60 mol% of 1-butene and 10 to 85 mol% of an α-olefin having 6 to 12 carbon atoms. Is preferable from the viewpoint of excellent adhesive properties at around room temperature, and more preferably a copolymer having a composition of 15 to 70 mol% of propylene, 5 to 50 mol% of 1-butene and 15 to 70 mol% of α-olefin. The pressure sensitive adhesive is preferred. Specific examples of this copolymer include propylene / 1-butene / 4-methyl-1-pentene copolymer.

  Further, when a copolymer composed of three components of propylene, 1-butene and an α-olefin having 5 to 12 carbon atoms is used as the main agent of the pressure-sensitive adhesive, the content ratio of the copolymer in the pressure-sensitive adhesive is usually , 30% by weight or more, preferably 60% by weight or more.

  Further, in the present invention, in order to improve the adhesive performance of the pressure-sensitive adhesive layer, in addition to the above-mentioned copolymer composed of three components of propylene, 1-pentene and α-olefin having 5 to 12 carbon atoms, other α -It can be set as the adhesive layer containing the olefin copolymer.

  As the other α-olefin copolymer, (A) at least two copolymers selected from ethylene, propylene and 1-butene, and (B) at least selected from ethylene and α-olefin co-oligomers. One type of copolymer may be mentioned. These copolymers may be used alone or in combination of two or more.

  Examples of the copolymer (A) comprising at least two kinds selected from ethylene, propylene, and 1-butene include, for example, an ethylene / propylene copolymer, an ethylene / 1-butene copolymer, and a propylene / 1-butene copolymer. Examples thereof include polymers.

  Specific examples of the copolymer (A) include those commercially available as trade names Tuffmer P, Tuffma-S, Tuffma-A, Tuffma-XR, etc., manufactured by Mitsui Petrochemical Industries, Ltd.

  The (B) co-oligomer of ethylene and α-olefin is, for example, a low molecular weight copolymer of ethylene and α-olefin, which is liquid at room temperature.

  Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 4 Examples thereof include α-olefins having 3 to 20 carbon atoms such as methyl-1-pentene.

  When the (B) co-oligomer is used as a subcomponent in the constituent component of the pressure-sensitive adhesive layer of the present invention, the content ratio of the (B) co-oligomer in the pressure-sensitive adhesive layer is usually 20% by weight or less, preferably 10%. % By weight or less.

  Specific examples of the aromatic group-containing olefin / diene copolymer or hydrogenated product thereof include, for example, a styrene / butadiene / styrene block copolymer, a styrene / ethylene / butylene / styrene block copolymer, a styrene / isoprene / Examples thereof include styrene block copolymers and hydrogenated products thereof such as styrene / ethylene / propylene / styrene block copolymers. These copolymers may be used alone or in combination of two or more.

  The styrene / ethylene / butylene / styrene block copolymer (hereinafter sometimes referred to as “SEBS”) is obtained by hydrogenating a styrene / butadiene / styrene block copolymer. Specific examples of this SEBS Examples thereof include those commercially available under the trade name Clayton G manufactured by Shell Chemical Co., Ltd.

  When using said SEBS as a subcomponent of the said adhesive layer, the content rate of SEBS which occupies for an adhesive layer is 50 weight% or less normally, Preferably it is 45 weight% or less.

  Furthermore, a styrene / isoprene / styrene block copolymer (hereinafter sometimes referred to as “SIS”) is a block copolymer having a styrene polymer block and an isoprene polymer block. As a specific example of this SIS, Examples thereof include those commercially available under the trade name Clayton D manufactured by Shell Chemical Co., Ltd.

  In addition, there are styrene, ethylene, propylene, and styrene (hereinafter sometimes referred to as “SEPS”) as hydrogenated substances of this SIS, and as a specific example of SEPS, for example, commercially available as a product name Septon 2063 manufactured by Kuraray Co., Ltd. What is being done.

  When using SEPS which is the SIS or its hydrogenated product as a subcomponent of the pressure-sensitive adhesive layer, the content of the SIS or SEPS in the pressure-sensitive adhesive layer is usually 50% by weight or less, preferably 30% by weight or less. It is. However, when the SEBS and SIS or SEPS are used at the same time, the content of these total amounts in the pressure-sensitive adhesive layer is preferably 45% by weight or less.

  As a constituent component of the pressure-sensitive adhesive layer, a mixed resin comprising a combination of the above-mentioned α-olefin copolymer consisting of propylene / 1-butene / 4-methyl-1-pentene and (A) copolymer When used, it is advantageous in that the glass transition temperature is lowered, the initial adhesive strength is adjusted to an appropriate range, and the low-temperature adhesive properties can be improved.

  Further, when a mixed resin composed of a combination of the above α-olefin copolymer and (B) co-oligomer is used as a constituent component of the pressure-sensitive adhesive layer, the glass transition temperature is lowered and the initial pressure-sensitive adhesive strength is in an appropriate range. This is advantageous in that the viscosity can be adjusted to an appropriate range.

  Moreover, when a mixed resin composed of a combination of the above α-olefin copolymer and SEBS, SIS and / or SEPS is used as a constituent component of the pressure-sensitive adhesive layer, the glass transition temperature is lowered and the initial adhesive strength is appropriate. This is advantageous in that it can be adjusted within a range and the low-temperature adhesive properties can be improved.

  In addition to the α-olefin copolymer or the other α-olefin copolymer, the pressure-sensitive adhesive layer may be used in addition to the styrene / diene copolymer shown above as a particularly preferable subcomponent. The subcomponent may be included.

  For example, copolymers of α-olefin and various vinyl compounds. They may contain thermoplastic elastomers typified by resins such as graft modified products, plasticizers such as liquid butyl rubber, tackifiers such as polyterpenes, and the like.

  In the present invention, these subcomponents have adhesive functional groups and unsaturated bonds, and deteriorate the adhesive strength with time after heating (heating, pressurization, humidity, UV exposure, etc.). The type, blending amount, and the like can be adjusted so that they do not occur.

  Furthermore, the pressure-sensitive adhesive used in the present invention includes conventionally known various tackifiers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, heat stabilizers, polymerization inhibitors. , Silane coupling agents, lubricants, inorganic or organic fillers, powders such as metal powders, pigments, particles, foils, etc. can do.

  Moreover, as a formation method of the adhesive layer of this invention, the well-known method used for manufacture of an adhesive film is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

  Moreover, in the said surface protection adhesive film, it is preferable that the said film base material and the said adhesive layer are integrally formed by coextrusion molding.

  As the co-extrusion molding, a method generally used for film production or the like can be adopted, and it is not particularly limited. Specifically, for example, an inflation method, a coextrusion T-die method, or the like can be used.

  In addition, the surface of the pressure-sensitive adhesive layer requires surface treatment for the purpose of adhesiveness control and pasting workability, such as corona discharge treatment, ultraviolet irradiation treatment, flame treatment, plasma treatment and sputter etching treatment. It can also be applied accordingly.

  Moreover, the thickness of the whole surface protective adhesive film of this invention is about 10-300 micrometers normally, Preferably it is about 30-200 micrometers.

  The pressure-sensitive adhesive film for surface protection of the present invention can be bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface (pressure-sensitive adhesive layer) as necessary. As a base material constituting the separator, there are paper and plastic film, but a plastic film is preferably used from the viewpoint of excellent surface smoothness.

  The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer Polyolefin films such as ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, etc. Polyester film, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate film Etc., and the like.

  The thickness of the film is usually about 5 to 200 μm, preferably about 10 to 100 μm. The adhesive layer bonding surface of the film may be appropriately treated with a release agent such as a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like.

On the other hand, the method for producing a surface protective pressure-sensitive adhesive film of the present invention is a method for producing a surface protective pressure-sensitive adhesive film comprising a step of integrally forming a film substrate and a pressure-sensitive adhesive layer by coextrusion molding,
The film base is provided with at least one base layer (I) made of a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof, and the base layer (I) is An ethylene vinyl alcohol copolymer containing 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or its derivative with respect to 100 parts by weight of a polyolefin resin and dispersed in the base material layer (I). And / or the length average length ( _LMD ) of the microregion of the derivative thereof is 3.5 μm or more and the content area ratio of the microregion is 4% or more.

  By using the production method of the present invention, the direction of the adhesive film for surface protection (flow line), the stretching direction of the metal plate as the adherend, etc. can be easily understood, and the surface protection with improved slipping on the back side of the film The adhesive film for use can be easily obtained by omitting complicated processes such as printing.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

<Measurement of length of micro area>
The major axis average length (L _MD ), minor axis average length (L _TD ), and content area ratio of the micro area of each adhesive film were calculated by cross-sectional observation (magnification: 5,000) of a scanning electron microscope (SEM). did. More specifically, the sample was vapor-stained for 2 hours at room temperature using a 0.5% ruthenium aqueous solution. Thereafter, the sample was microtomed, fixed to a sample stage with a conductive adhesive tape, and subjected to Pt—Pd sputtering for 20 seconds to observe each measurement.

<Evaluation of muscle (flow)>
The surface of each adhesive film was visually observed from a distance of 30 cm under a fluorescent lamp. The evaluation criteria are as follows.
・ If the streaks (flow lines) are particularly distinguishable: ◎
・ If muscles (flow lines) can be clearly distinguished: ○ ⁺
・ If muscles (flow lines) can be identified: ○
・ If the muscle (flow line) cannot be identified: ×

<Measurement of ten-point average surface roughness (Rz)>
The ten-point average surface roughness (Rz) (μm) was measured using a value measured according to JIS-B0651. More specifically, a stylus type surface roughness measuring instrument (manufactured by KLA-Tencor Corporation, P-15, measurement direction: moving the needle perpendicular to the stretching direction of the film, measurement range: 8 mm, stylus moving speed: 50 μm / Sec, stylus pressure: 6 mg).

<Measurement of surface friction force>
Each adhesive film is cut into 5cm x 15cm (flow direction) and placed on a metal horizontal table, and an iron jig (contact area: 60cm ² , load: 3kg) is placed on the back of the film. The surface friction force (N) was measured at a speed of 0.3 m / min. In addition, in the surface protection use of a metal plate, the friction force is preferably 15 N or less, and more preferably 5 to 14 N.

[Example 1]
As a polyolefin mixture used for the base material layer (I), for 100 parts by weight of polyethylene (manufactured by Nippon Polyethylene Co., Ltd., Novatec LD LF547), for 7 parts by weight of an ethylene vinyl alcohol copolymer (manufactured by Yufu Kogyo Co., Ltd., Pyroyl 1010S) It was. Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, an extruder temperature: 200 ° C., a die temperature: 200 ° C., and the resin is melted), and a two-layer adhesive film (thickness: A base material layer (base material layer (I)) / adhesive layer = 100 μm / 9 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 5.6 μm, the content area ratio is 15.9%, the aspect ratio (L _MD / L _TD ) is 9.3, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) It was confirmed that the roughness (Rz) was 4.8 μm.

[Example 2]
As a polyolefin mixture used for the base material layer (I), 7 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray Co., E171B) was used with respect to 100 parts by weight of polyethylene (Novatec LD LC604, manufactured by Nippon Polyethylene Co., Ltd.). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single screw extruder, the extruder temperature is 200 ° C., the die temperature is 200 ° C., the resin is melted), and two layers of adhesive films (thickness: A base material (base material layer (I)) / adhesive layer = 100 μm / 8 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 4.8 μm, the content area ratio is 15.5%, the aspect ratio (L _MD / L _TD ) is 8.7, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) The roughness (Rz) was confirmed to be 5.2 μm.

Example 3
As a polyolefin mixture used for the base material layer (I), 7 parts by weight of ethylene vinyl alcohol copolymer (Kuraray Co., E171B) was used with respect to 100 parts by weight of polyethylene (Novatec LD LC720, manufactured by Nippon Polyethylene Co., Ltd.). Moreover, 100 weight part of polyethylene (Nippon Polyethylene Co., Ltd. product, Novatec LD LC720) was used as the base material layer (II). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 1320P) was used as an adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, the resin is melted at an extruder temperature: 200 ° C. and a die temperature: 200 ° C.), and a three-layer adhesive film (thickness: Substrate layer (I) / substrate layer (II) / adhesive layer = 5 μm / 95 μm / 8 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 6.7 μm, the content area ratio is 16.2%, the aspect ratio (L _MD / L _TD ) is 14.9, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) It was confirmed that the roughness (Rz) was 5.6 μm.

Example 4
As a polyolefin mixture used for the base material layer (I), 12 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray, E171B) was used with respect to 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LF440C). Moreover, 100 weight part of polyethylene (Nippon Polyethylene Co., Ltd. product, Novatec LD LC720) was used as the base material layer (II). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 1320P) was used as an adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, the resin is melted at an extruder temperature: 200 ° C. and a die temperature: 200 ° C.), and a three-layer adhesive film (thickness: Base layer (I) / base layer (II) / adhesive layer = 5 μm / 94 μm / 8 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 5.9 μm, the content area ratio is 21.5%, the aspect ratio (L _MD / L _TD ) is 11.6, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) It was confirmed that the roughness (Rz) was 7.8 μm.

Example 5
As a polyolefin mixture used for the base material layer (I), 12 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray Co., E171B) is used with respect to 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LF443). To 100 parts by weight of the mixture, 1.5 parts by weight of synthetic silica (average particle size: 5 μm, manufactured by Tokai Chemical Industry Co., Ltd., ML-369) was used. Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single screw extruder, the extruder temperature is 200 ° C., the die temperature is 200 ° C., the resin is melted), and two layers of adhesive films (thickness: A base material layer (base material layer (I)) / adhesive layer = 100 μm / 10 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 5.2 μm, the content area ratio is 20.8%, the aspect ratio (L _MD / L _TD ) is 9.3, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) The roughness (Rz) was confirmed to be 8.2 μm.

Example 6
As a polyolefin mixture used for the base material layer (I), 12 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray Co., E171B) is used with respect to 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LF443). For 100 parts by weight of the mixture, 1.5 parts by weight of synthetic zeolite (average particle size: 5 μm) was used. Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, an extruder temperature: 200 ° C., a die temperature: 200 ° C., and the resin is melted), and a two-layer adhesive film (thickness: A base material layer (base material layer (I)) / adhesive layer = 100 μm / 9 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 5.6 μm, the content area ratio is 24.3%, the aspect ratio (L _MD / L _TD ) is 11.7, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) The roughness (Rz) was confirmed to be 8.5 μm.

Example 7
As the polyolefin mixture used for the base material layer (I), 12 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray, E171B) is used with respect to 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LF440C). For 100 parts by weight of the mixture, 1.5 parts by weight of synthetic zeolite (average particle size: 5 μm) was used. Moreover, 100 weight part of polyethylene (Nippon Polyethylene Co., Ltd. product, Novatec LD LC720) was used as the base material layer (II). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 1320P) was used as an adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, the resin is melted at an extruder temperature: 200 ° C. and a die temperature: 200 ° C.), and a three-layer adhesive film (thickness: Substrate layer (I) / substrate layer (II) / adhesive layer = 5 μm / 95 μm / 8 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 4.7 μm, the content area ratio is 22.4%, the aspect ratio (L _MD / L _TD ) is 11.8, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) It was confirmed that the roughness (Rz) was 8.8 μm.

Example 8
As the polyolefin mixture used for the base material layer (I), 12 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray, E171B) is used with respect to 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LF440C). For 100 parts by weight of the mixture, 1.5 parts by weight of synthetic zeolite (average particle size: 10 μm) was used. Moreover, 100 weight part of polyethylene (Nippon Polyethylene Co., Ltd. product, Novatec LD LC720) was used as the base material layer (II). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 1320P) was used as an adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, the resin is melted at an extruder temperature: 200 ° C. and a die temperature: 200 ° C.), and a three-layer adhesive film (thickness: Substrate layer (I) / substrate layer (II) / adhesive layer = 5 μm / 95 μm / 10 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 4.5 μm, the content area ratio is 21.8%, the aspect ratio (L _MD / L _TD ) is 10.7, and the ten-point average surface of the outermost surface of the adhesive film (base material layer (I)) The roughness (Rz) was confirmed to be 9.2 μm.

Example 9
As the polyolefin mixture used for the base material layer (I), 12 parts by weight of an ethylene vinyl alcohol copolymer (Kuraray, E171B) is used with respect to 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LF440C). Synthetic zeolite (average particle size: 10 μm) (3.0 parts by weight) was used with respect to 100 parts by weight of the mixture. Moreover, 100 weight part of polyethylene (Nippon Polyethylene Co., Ltd. product, Novatec LD LC720) was used as the base material layer (II). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 1320P) was used as an adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, the resin is melted at an extruder temperature: 200 ° C. and a die temperature: 200 ° C.), and a three-layer adhesive film (thickness: Base layer (I) / Base layer (II) / Adhesive layer = 5 μm / 95 μm / 9 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 5.3 μm, the content area ratio is 23.5%, the aspect ratio (L _MD / L _TD ) is 9.0, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) It was confirmed that the roughness (Rz) was 9.7 μm.

Example 10
As a polyolefin mixture used for the base material layer (I), 3 parts by weight of ethylene vinyl alcohol copolymer (Kuraray, E171B) was used with respect to 100 parts by weight of polyethylene (Novatec LD LC720, manufactured by Nippon Polyethylene Co., Ltd.). Moreover, 100 weight part of polyethylene (Nippon Polyethylene Co., Ltd. product, Novatec LD LC720) was used as the base material layer (II). Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 1320P) was used as an adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, the resin is melted at an extruder temperature: 200 ° C. and a die temperature: 200 ° C.), and a three-layer adhesive film (thickness: Substrate layer (I) / substrate layer (II) / adhesive layer = 5 μm / 95 μm / 10 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 4.3 μm, the content area ratio is 8.2%, the aspect ratio (L _MD / L _TD ) is 4.7, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) The roughness (Rz) was confirmed to be 3.2 μm.

[Comparative Example 1]
As a base material layer, 100 parts by weight of polyethylene (manufactured by Nippon Polyethylene Co., Ltd., Novatec LD LF547) was used. Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, an extruder temperature: 200 ° C., a die temperature: 200 ° C., and the resin is melted), and a two-layer adhesive film (thickness: Substrate layer / adhesive layer = 100 μm / 9 μm) was obtained.

  When the cross-sectional observation (magnification: 5,000) of the base material layer of the produced adhesive film was carried out by SEM, it was confirmed that there is no substance stripe. Moreover, it was confirmed that the ten-point average surface roughness (Rz) of the outermost surface of the adhesive film is 0.4 μm.

[Comparative Example 2]
As a polyolefin mixture used for the base material layer (I), for 100 parts by weight of polyethylene (Nippon Polyethylene, Novatec LD LC604), 10 parts by weight of ethylene vinyl acetate copolymer (EVA) (Nippon Polyethylene, LV440) It was. Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single screw extruder, the extruder temperature is 200 ° C., the die temperature is 200 ° C., the resin is melted), and two layers of adhesive films (thickness: A base material layer (base material layer (I)) / adhesive layer = 100 μm / 10 μm was obtained.

  When the cross-sectional observation (magnification: 5,000) of the base material layer of the produced adhesive film was carried out by SEM, it was confirmed that there is no substance stripe. Moreover, it was confirmed that the ten-point average surface roughness (Rz) of the outermost surface of the adhesive film is 0.7 μm.

[Comparative Example 3]
As a polyolefin mixture used for the base material layer (I), 1.5 parts by weight of an ethylene vinyl alcohol copolymer (manufactured by Yufu Kogyo Co., Ltd., Pyroyl 1010S) per 100 parts by weight of polyethylene (manufactured by Nippon Polyethylene, Novatec LDLC604). Using. Further, 100 parts by weight of a hydrogenated polymer (manufactured by JSR, Dynalon 8601P) was used as the adhesive layer.

  These resin materials are formed into a film by melt coextrusion molding (in a single-screw extruder, an extruder temperature: 200 ° C., a die temperature: 200 ° C., and the resin is melted), and a two-layer adhesive film (thickness: A base material layer (base material layer (I)) / adhesive layer = 100 μm / 9 μm was obtained.

When the substrate of the adhesive film was produced (base material layer (I)) was cross-sectional observation by SEM, the major axis average length of micro-regions in the substrate layer (I) (ethylene-vinyl alcohol copolymer domains) (L _MD ) Is 3.1 μm, the content area ratio is 3.5%, the aspect ratio (L _MD / L _TD ) is 6.89, and the ten-point average surface of the adhesive film outermost surface (base material layer (I)) It was confirmed that the roughness (Rz) was 1.8 μm.

  According to the said method, each measurement and evaluation of the produced adhesive film were performed. The obtained results are shown in Table 1.

  From the results of Table 1 above, when the surface protective sheet prepared according to the present invention was used (Examples 1 to 10), in any of the examples, the surface of the base material was not impaired without impairing the film formability. It was revealed that visible streaks can be expressed and the effect of reducing the surface friction force is paralleled.

  On the other hand, when an ethylene vinyl alcohol copolymer and / or a derivative thereof was not used (Comparative Example 1), a visible line could not be expressed on the outermost surface of the base material, and the surface frictional force was increased. became. Further, when ethylene vinyl acetate copolymer was used instead of ethylene vinyl alcohol copolymer and / or its derivative (Comparative Example 2), the content of ethylene vinyl alcohol copolymer and / or its derivative was 1.5. In the case of using parts by weight (Comparative Example 3), effective microphase separation as in the present invention did not occur, so that visible streaks could not be expressed on the outermost surface of the substrate, and the surface frictional force increased. As a result. Therefore, in any of the comparative examples, it is impossible to parallel the expression of the direction (flow line) of the visible adhesive film and the reduction of the surface friction force, which is not suitable for the surface protective adhesive film in the application of the present invention. It became clear.

  From the above, the pressure-sensitive adhesive film for surface protection of the present invention is a pressure-sensitive adhesive film for surface protection that can easily understand the direction (flow line) of the pressure-sensitive adhesive film and improve the slidability of the back surface of the film to improve workability. I understand.

Claims (14)

A film substrate for surface protection comprising at least one base layer (I) comprising a polyolefin-based resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof, wherein the base layer (I) Ethylene vinyl alcohol containing 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or a derivative thereof with respect to 100 parts by weight of the polyolefin resin, and dispersed in the base material layer (I) Surface protective film base material characterized in that the average length (L _MD ) of the microregion of the copolymer and / or derivative thereof is 3.5 μm or more and the content area ratio of the microregion is 4% or more . 2. The surface protection according to claim 1, wherein a ratio (L _MD / L _TD ) of a major axis average length (L _MD ) and a minor axis average length (L _TD ) of the minute region is 2 or more. Film substrate.   The said base material layer (I) is provided in the outermost layer of the said surface protection film base material, The film base material for surface protection of Claim 1 or 2 characterized by the above-mentioned.   The film base material for surface protection according to claim 1, wherein the base material layer (I) has a ten-point average surface roughness (Rz) of 2.0 μm or more.   The base material layer (I) further contains 0.5 to 10 parts by weight of fine particles with respect to 100 parts by weight of a polyolefin mixture composed of the polyolefin resin and the ethylene vinyl alcohol copolymer and / or a derivative thereof. The film substrate for surface protection according to any one of claims 1 to 4.   6. The film substrate for surface protection according to claim 5, wherein the fine particles are synthetic zeolite and / or synthetic silica.   The average particle diameter of the fine particles is 1 to 20 µm, The film substrate for surface protection according to claim 5 or 6.   The film substrate for surface protection according to claim 5, wherein an average particle diameter of the fine particles is larger than a thickness of the substrate layer (I).   A pressure-sensitive adhesive film for surface protection, comprising a pressure-sensitive adhesive layer on one side of the surface-protective film base material according to claim 1.   The surface-protective pressure-sensitive adhesive film according to claim 9, wherein the surface-protective film substrate and the pressure-sensitive adhesive layer are integrally formed by coextrusion molding. A method for producing an adhesive film for surface protection comprising a step of integrally forming a film substrate and an adhesive layer by coextrusion molding,
The film base is provided with at least one base layer (I) made of a polyolefin resin containing an ethylene vinyl alcohol copolymer and / or a derivative thereof, and the base layer (I) is An ethylene vinyl alcohol copolymer containing 3 to 20 parts by weight of an ethylene vinyl alcohol copolymer and / or its derivative with respect to 100 parts by weight of a polyolefin resin and dispersed in the base material layer (I) And / or its derivative microregions have a major axis length average (L _MD ) of 3.5 μm or more, a minor region average major axis length (L _MD ) of 2 μm or more, and a content area ratio of the minute region of 4% or more. A method for producing a pressure-sensitive adhesive film for surface protection. 12. The surface protection according to claim 11, wherein a ratio (L _MD / L _TD ) of a major axis average length (L _MD ) and a minor axis average length (L _TD ) of the minute region is 2 or more. A method for producing an adhesive film.   The method for producing an adhesive film for surface protection according to claim 11 or 12, wherein the ten-point average surface roughness (Rz) of the base material layer (I) is 2.0 µm or more.   The base material layer (I) further contains 0.5 to 10 parts by weight of fine particles with respect to 100 parts by weight of a polyolefin mixture composed of the polyolefin resin and the ethylene vinyl alcohol copolymer and / or a derivative thereof. The manufacturing method of the adhesive film for surface protection in any one of Claims 11-13 characterized by the above-mentioned.