JP2013166833A - Surface-protecting sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provided a surface-protecting sheet which includes a base-material layer and an adhesive layer, and which exhibits no impairment to the external appearance and feel thereof even if foreign matter is present on the outermost surface of the base-material layer.SOLUTION: A surface-protecting sheet 100 includes a base-material layer 20 and an adhesive layer 10, and is obtained by integrally forming the base-material layer and the adhesive layer using co-extrusion moulding. The surface roughness (Ra) of the outermost surface of the base-material layer is in the range of 0.10-0.60 μm. The 60-degree gloss of the outermost surface of the base-material layer is in the range of 20.0-71.5.

Description

  The present invention relates to a surface protective sheet. In detail, this invention relates to the surface protection sheet containing a base material layer and an adhesion layer. The surface protective sheet of the present invention includes, for example, a metal plate, a paint plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate and other members, a polarizing film, an optical member such as a liquid crystal panel, and an electronic member. When transporting, processing, curing, etc., it is used for applications such as sticking to the surface for protection.

  The surface protective sheet is generally provided with an adhesive layer on one side of the base material layer. As a method for producing a surface protective sheet including such a base material layer and an adhesive layer, a method in which the base material layer and the adhesive layer are integrally formed by coextrusion molding has been proposed (for example, see Patent Document 1). .

  In general, not a few foreign substances can be present on the outermost surface of the base material layer in the surface protective sheet. For this reason, in the conventional surface protection sheet, when the outermost surface of a base material layer is made smooth, there exists a problem that an external appearance and a tactile sensation will be impaired because of the foreign material which exists.

JP-A-61-103975

  An object of the present invention is to provide a surface protection sheet including a base material layer and an adhesive layer, and the surface protection sheet does not impair the appearance and feel even if foreign matter is present on the outermost surface of the base material layer. There is to do.

The surface protective sheet of the present invention is
A surface protective sheet comprising a base material layer and an adhesive layer,
The base material layer and the adhesive layer are integrally formed by coextrusion molding,
The surface roughness Ra of the outermost surface of the base material layer is 0.10 μm to 0.60 μm,
60 degree gloss of the outermost surface of this base material layer is 20.0-71.5.

  In a preferred embodiment, the surface roughness Ra is 0.20 μm to 0.60 μm, and the 60 degree gloss is 20.0 to 65.0.

  In preferable embodiment, the said base material layer contains polyolefin resin as a main component.

  In preferable embodiment, the said base material layer contains a white type | system | group layer.

  In a preferred embodiment, the white layer contains a polyethylene resin as a main component.

  In a preferred embodiment, the polyethylene resin contains autoclaved polyethylene as a main component.

  In a preferred embodiment, the white layer further includes a resin different from the polyethylene resin.

  In a preferred embodiment, the resin different from the polyethylene resin is at least one selected from a polypropylene resin and an ethylene / vinyl acetate copolymer.

  In a preferred embodiment, the white layer includes particles.

  In preferable embodiment, the said base material layer contains a black-type layer.

  In a preferred embodiment, the black layer contains a polyethylene resin as a main component.

  In a preferred embodiment, the adhesive layer contains a styrenic thermoplastic elastomer.

  According to the present invention, there is provided a surface protective sheet comprising a base material layer and an adhesive layer, the surface protective sheet not impairing the appearance and tactile sensation even if foreign matter is present on the outermost surface of the base material layer. can do.

It is sectional drawing which shows typically the example of 1 structure of the surface protection sheet of this invention.

  The surface protective sheet of the present invention is a surface protective sheet including a base material layer and an adhesive layer. The surface protective sheet of the present invention may contain any appropriate other layer as long as the effects of the present invention are not impaired.

  The thickness of the base material layer is preferably 20 μm to 300 μm, more preferably 30 μm to 250 μm, still more preferably 40 μm to 200 μm, particularly preferably 45 μm to 150 μm, and most preferably 50 μm to 100 μm. is there. If the thickness of the base material layer falls within the above range, the base material layer is less likely to be torn or torn when it is peeled off after the surface protective sheet of the present invention is applied to the adherend. Since the increase in stiffness can be suppressed, it is difficult for floating and the like to occur after the surface protective sheet of the present invention is applied to the adherend.

  The thickness of the adhesive layer is preferably 1 μm to 50 μm, more preferably 2 μm to 40 μm, further preferably 3 μm to 30 μm, particularly preferably 4 μm to 20 μm, and most preferably 5 μm to 10 μm. . By keeping the thickness of the pressure-sensitive adhesive layer within the above range, it becomes easy to control the layer structure when producing the surface protective sheet of the present invention by coextrusion molding, and the surface protective sheet has sufficient mechanical strength. Can be obtained.

  The total thickness of the surface protective sheet of the present invention is preferably 30 μm to 150 μm, more preferably 35 μm to 140 μm, still more preferably 40 μm to 130 μm, particularly preferably 45 μm to 120 μm, and most preferably. Is 50 μm to 110 μm. By keeping the total thickness of the surface protective sheet of the present invention within the above range, a surface protective sheet having excellent mechanical properties and excellent handleability can be obtained.

  The surface protective sheet of the present invention is formed by integrally forming a base material layer and an adhesive layer by coextrusion molding. As the coextrusion molding, any appropriate coextrusion molding generally used for production of films, sheets and the like can be adopted. As the coextrusion molding, for example, an inflation method, a coextrusion T-die method, or the like can be adopted. These coextrusion molding is preferable in terms of cost and productivity.

  In the surface protective sheet of the present invention, the outermost surface roughness Ra of the base material layer is 0.10 μm to 0.60 μm, preferably 0.20 μm to 0.60 μm, more preferably 0.25 μm to The thickness is 0.60 μm, more preferably 0.30 μm to 0.60 μm, particularly preferably 0.35 μm to 0.60 μm, and most preferably 0.40 μm to 0.60 μm. When the surface roughness Ra of the outermost surface of the base material layer falls within the above range, the outermost surface of the base material layer can be effectively roughened. It is possible to provide a surface protective sheet that does not impair the appearance and feel even if it is inherent. In addition, the detail of the measuring method of surface roughness Ra is mentioned later.

  In the surface protective sheet of the present invention, the 60 ° gloss on the outermost surface of the base material layer is 20.0 to 71.5, preferably 20.0 to 65.0, more preferably 20.0 to 63. 0.0, more preferably 20.0 to 60.0, particularly preferably 20.0 to 55.0, and most preferably 20.0 to 50.0. When the 60-degree gloss on the outermost surface of the base material layer falls within the above range, the outermost surface of the base material layer can be effectively matted, and even if foreign matter is present on the outermost surface of the base material layer. It is possible to provide a surface protective sheet that does not impair the appearance and feel even if it is inherent. The details of the 60-degree gloss measurement method will be described later.

  In the surface protective sheet of the present invention, it is preferable that both the surface roughness Ra of the outermost surface of the base material layer and the 60 degree gloss of the outermost surface of the base material layer fall within the above range. For example, in the surface protective sheet of the present invention, preferably, the outermost surface roughness Ra of the base material layer is 0.10 μm to 0.60 μm, and the outermost surface of the base material layer has a 60 degree gloss. It is 20.0-71.5, More preferably, surface roughness Ra is 0.20 micrometer-0.60 micrometer, and 60 degree gloss is 20.0-65.0. When the surface roughness Ra of the outermost surface of the base material layer and the 60 degree gloss of the outermost surface of the base material layer are within the above ranges, the outermost surface of the base material layer is effectively roughened and matted. It is possible to effectively provide a surface protective sheet that does not impair the appearance and feel even if foreign substances are present on the outermost surface of the base material layer.

  The base material layer preferably contains a polyolefin resin as a main component. When the base material layer contains a polyolefin-based resin as a main component, it can have heat resistance, solvent resistance, and flexibility, and can be easily wound into a roll. The polyolefin resin contained in the base material layer may be only one type or two or more types.

  The base material layer may be a single layer or a plurality of layers.

  Here, the “main component” in the present invention is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably 80% by weight or more. Yes, and most preferably 90% by weight or more.

  Examples of the polyolefin resin include a polyethylene resin, a polypropylene resin, and an ethylene / α-olefin copolymer.

  Specific examples of the polyolefin resin include polyethylene resins such as high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low density polyethylene (LLDPE); homopolypropylene, block Polypropylene resins such as polypropylene and random polypropylene; poly (1-butene); poly (4-methyl-1-pentene); ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer Polymer, 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 Ethylene · alpha-olefin copolymer, such as alcohol copolymers; and the like.

  When the base material layer is composed of two or more layers, each adjacent layer should be selected as a resin component that can form a strong bond with each other by melt coextrusion. Is preferred.

  The base material layer may include a white layer. When the base material layer includes a white layer, a surface protective sheet having excellent weather resistance can be obtained.

  The base material layer may include a black layer. When the base material layer includes a black layer, a surface protective sheet having excellent weather resistance can be obtained.

  The base material layer preferably includes at least two layers of a white layer and a black layer. When the base material layer includes at least two layers of a white layer and a black layer, a surface protective sheet having excellent weather resistance can be obtained.

  When the base material layer includes at least two layers of a white layer and a black layer, examples of the laminated structure of the surface protective sheet of the present invention include “white layer / black layer / adhesive layer”, “black layer” As long as the effects of the present invention are not impaired, such as “/ white color layer / adhesive layer”, any appropriate laminated structure can be adopted. FIG. 1 is a cross-sectional view schematically showing a configuration example in the case where the surface protective sheet 100 of the present invention has a laminated configuration of “white layer 21 / black layer 22 / adhesive layer 10”. The white layer 21 and the black layer 22 become the base material layer 20.

  The white layer is a layer showing a white color tone. For example, the whiteness defined by JIS-L-1015 is preferably 60% or more, more preferably 70% or more, and still more preferably. It is 80% or more, and particularly preferably 85% or more. The white layer preferably contains a white pigment. Any appropriate white pigment can be adopted as the white pigment. An example of such a white pigment is titanium oxide. When the white layer contains a white pigment, the content is preferably 0.1% by weight to 50% by weight, more preferably 1% by weight to 40%, with respect to the resin component forming the white layer. % By weight, more preferably 2% by weight to 30% by weight. When the content ratio of the white pigment to the resin component forming the white layer falls within the above range, a surface protective sheet having excellent weather resistance can be obtained, and extrudability and other moldability are also excellent.

  The white layer preferably contains a polyolefin resin as a main component. Examples of the polyolefin resin that can be contained in the white layer include a polyethylene resin, a polypropylene resin, and an ethylene / α-olefin copolymer. As the polyolefin resin that can be contained in the white layer, only one kind may be used, or two or more kinds may be used.

  Specific examples of the polyolefin resin that can be contained in the white layer include polyethylene such as high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Polypropylene resins such as homopolypropylene, block polypropylene, and random 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 Body, ethylene-alpha-olefin copolymers such as ethylene-vinyl alcohol copolymer; and the like.

  The content of the polyolefin-based resin in the white layer is preferably 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and particularly preferably 80% by weight or more. Yes, most preferably 90% by weight or more.

  The white layer preferably contains a polyethylene resin as a main component. When the white layer contains a polyethylene resin as a main component, the base layer can have heat resistance, solvent resistance, and flexibility, and the surface protective sheet of the present invention can be easily wound into a roll. Is possible.

  When the white layer includes a polyethylene resin as a main component, the polyethylene resin preferably includes a low density polyethylene as a main component. When the polyethylene resin contains low-density polyethylene as a main component, the base material layer can have sufficient heat resistance, solvent resistance, and flexibility, and the surface protection sheet of the present invention can be more easily rolled. It becomes possible to wind up.

  Examples of the polyethylene resin that can be included in the white layer include autoclaved polyethylene and tubular polyethylene.

  Autoclaved polyethylene has a relatively wide molecular weight distribution and a large amount of high molecular weight components compared to tubular polyethylene. For this reason, when the autoclave method polyethylene is adopted as the main component of the polyethylene resin that can be contained in the white layer, the outermost surface of the white layer can be effectively matted. In addition, autoclaved polyethylene has long chain branching, and an expansion phenomenon accompanying pressure loss called swell occurs during extrusion. For this reason, when the autoclave method polyethylene is adopted as the main component of the polyethylene resin that can be contained in the white layer, the outermost surface of the white layer can be effectively roughened. As the polyethylene resin that can be contained in the white layer, autoclave polyethylene and tubular polyethylene may be used in combination.

The density of the polyethylene resin that can be contained in the white layer is preferably 0.880 g / cm ^{3 to} 0.940 g / cm ³ , more preferably 0.880 g / cm ^{3 to} 0.923 g / cm ³ . , more preferably from ^{0.880g / cm 3 ~0.915g / cm 3} . When the density of the polyethylene resin that can be contained in the white layer falls within the above range, the outermost surface of the white layer can be effectively roughened and matted.

  The MFR of the polyethylene resin that can be contained in the white layer is preferably 0.1 g / 10 min to 10 g / 10 min, more preferably 0.3 g / 10 min to 5 g / 10 min, and still more preferably 0.3 g / 10 min to 3 g / 10 min. When the MFR of the polyethylene resin that can be contained in the white layer falls within the above range, the outermost surface of the white layer can be effectively roughened and matte.

  When the white layer includes a polyethylene resin as a main component, the white layer may further include a resin different from the polyethylene resin (this may be referred to as a “different resin”). When the white layer contains a different resin, combined with the polyethylene resin, the outermost surface of the white layer can be effectively roughened and matted. As such a different resin, any appropriate resin can be adopted as long as the effects of the present invention are not impaired. Examples of such a different resin include at least one selected from a polypropylene resin and an ethylene / vinyl acetate copolymer. When the white layer contains such a different resin, the content ratio of the different resin in the white layer is preferably 5% by weight to 70% by weight, more preferably 10% by weight to 50% by weight. More preferably, it is 10 to 40% by weight, and particularly preferably 10 to 30% by weight. When the content ratio of such a different resin in the white layer falls within the above range, combined with the polyethylene resin, the outermost surface of the white layer is more effectively roughened and matted. can do.

  The white layer may contain particles. When the white layer contains particles, the outermost surface of the white layer can be effectively roughened and matted. As such particles, any appropriate particles can be adopted as long as the effects of the present invention are not impaired. Examples of such particles include organic particles and inorganic particles. Examples of the organic particles include acrylic beads prepared from PMMA and the like. Examples of the inorganic particles include silica and zeolite. When the white layer contains such particles, the content ratio of such particles in the white layer is preferably 0.3 wt% to 10 wt%, more preferably 0.5 wt% to 7 wt%. % By weight, more preferably 0.5% by weight to 5% by weight, and particularly preferably 0.5% by weight to 3% by weight. When the content ratio of such particles in the white layer falls within the above range, the outermost surface of the white layer can be more effectively roughened and matted.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of a white type | system | group layer according to the objective. Such thickness is preferably 2 μm to 100 μm, more preferably 3 μm to 80 μm, still more preferably 4 μm to 60 μm, and particularly preferably 5 μm to 50 μm.

  The black layer is a layer showing a black color tone. The black layer preferably contains a black pigment. Any appropriate black pigment can be adopted as the black pigment. An example of such a black pigment is carbon black. When the black layer contains a black pigment, the content is preferably 0.01% by weight to 10% by weight and more preferably 0.1% by weight with respect to the resin component forming the black layer. -5% by weight, more preferably 0.5-3% by weight. When the content ratio of the black pigment to the resin component forming the black layer falls within the above range, a surface protective sheet having excellent weather resistance can be obtained, and extrudability and other moldability are also excellent.

  The black layer preferably contains a polyolefin resin as a main component. Examples of the polyolefin resin that can be contained in the black layer include a polyethylene resin, a polypropylene resin, and an ethylene / α-olefin copolymer. As the polyolefin resin that can be contained in the black layer, only one kind may be used, or two or more kinds may be used.

  Specific examples of polyolefin resins that can be included in the black layer include polyethylenes such as high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low density polyethylene (LLDPE). Polypropylene resins such as homopolypropylene, block polypropylene, and random 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 Body, ethylene-alpha-olefin copolymers such as ethylene-vinyl alcohol copolymer; and the like.

  The content ratio of the polyolefin resin in the black layer is preferably 50% by weight or more, more preferably 60% by weight or more, further preferably 70% by weight or more, and particularly preferably 80% by weight or more. Yes, most preferably 90% by weight or more.

  The black layer preferably contains a polyethylene resin as a main component. When the black layer contains a polyethylene resin as a main component, the base layer can have heat resistance, solvent resistance, and flexibility, and the surface protection sheet of the present invention can be easily wound into a roll. Is possible.

  When the black layer contains a polyethylene resin as a main component, the polyethylene resin preferably contains at least one selected from low density polyethylene and linear low density polyethylene. When the polyethylene resin contains at least one selected from low-density polyethylene and linear low-density polyethylene, the base material layer can have sufficient heat resistance, solvent resistance, and flexibility. It becomes possible to wind the surface protective sheet in a roll shape more easily.

The density of the polyethylene resin that can be contained in the black layer is preferably 0.880 g / cm ^{3 to} 0.940 g / cm ³ , more preferably 0.880 g / cm ^{3 to} 0.924 g / cm ³ . , more preferably from ^{0.880g / cm 3 ~0.915g / cm 3} . When the density of the polyethylene resin that can be contained in the black layer falls within the above range, the base layer can have sufficient heat resistance, solvent resistance, and flexibility, and the surface protective sheet of the present invention can be obtained. It can be more easily wound up in a roll shape.

  The MFR of the polyethylene resin that can be contained in the black layer is preferably 1 g / 10 min to 10 g / 10 min, more preferably 1 g / 10 min to 5 g / 10 min, and even more preferably 2 g / 10 min to 4 g / 10 min. is there. When the MFR of the polyethylene resin that can be contained in the black layer falls within the above range, the base material layer can have sufficient heat resistance, solvent resistance, and flexibility, and the surface protective sheet of the present invention can be obtained. It can be more easily wound up in a roll shape.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of a black type | system | group layer according to the objective. Such thickness is preferably 2 μm to 100 μm, more preferably 3 μm to 80 μm, still more preferably 4 μm to 60 μm, and particularly preferably 5 μm to 50 μm.

  The base material layer may contain any appropriate additive. Examples of such additives include antioxidants, ultraviolet absorbers, anti-aging agents, light stabilizers, antistatic agents, surface lubricants, leveling agents, plasticizers, low molecular weight polymers, corrosion inhibitors, and polymerization prohibitions. Agents, silane coupling agents, inorganic and organic fillers (eg, calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, etc.), metal powders, colorants, pigments, heat stabilizers, anti-spot agents, lubricants And anti-blocking agents.

  A back surface treatment may be applied to the outermost layer on the side opposite to the adhesive layer of the base material layer. Any appropriate method can be adopted as the back surface processing method as long as the effects of the present invention are not impaired. Examples of the back treatment method include surface treatment such as embossing and uneven processing, and a method of containing a long-chain alkyl back treatment agent and a fatty acid derivative. Such long-chain alkyl-based back treatment agents and fatty acid derivatives may be used alone or in combination of two or more.

  When the base material layer contains a fatty acid derivative, the content ratio of the fatty acid derivative in the base material layer is preferably 0.05% by weight to 1.00% by weight with respect to the resin component in the base material layer, More preferably, it is 0.10 weight%-0.90 weight%, More preferably, it is 0.30 weight%-0.80 weight%. If the content ratio of the fatty acid derivative in the base material layer is within the above range with respect to the resin component in the base material layer, the roll-shaped surface protection sheet of the present invention can be easily rewound. Thus, the mold release effect can be sufficiently exhibited, and the contamination of the fatty acid derivative by bleeding can be sufficiently suppressed.

  The fatty acid derivative refers to a compound containing a fatty acid derivative structure in the molecular structure.

  Examples of the fatty acid derivatives include saturated fatty acid bisamides, unsaturated fatty acid bisamides, aromatic bisamides, substituted ureas, and fatty acid metal salts. Specific examples of fatty acid derivatives include methylene bis stearamide, ethylene bis stearamide, ethylene bis oleate, N, N-dioleyl adipamide, N-stearyl-N′-stearyl urea, and the like. N-stearyl-N′-stearylamide, zinc stearate and the like.

  The fatty acid derivative is preferably a fatty acid amide, more preferably at least one selected from methylene bis stearic acid amide, ethylene bis stearic acid amide, and N-stearyl-N′-stearyl acid amide.

  The fatty acid derivative preferably has a melting point of 100 ° C. or higher. A fatty acid derivative having a melting point of less than 100 ° C. has a significant transfer to the surface of the adhesive layer, and there is a risk that a decrease in adhesive strength is likely to occur.

  The adhesive layer preferably contains a thermoplastic resin as a main component. The thermoplastic resin contained in the adhesive layer may be only one type or two or more types.

  Any appropriate thermoplastic resin can be adopted as the thermoplastic resin. Examples of such thermoplastic resins include olefin resins, aromatic group-containing olefin / diene copolymers, styrene resins, ester resins, and the like. Among these thermoplastic resins, styrene resins are preferable, and styrene thermoplastic elastomers are more preferable.

  The styrenic thermoplastic elastomer is preferably a styrenic block copolymer or a hydrogenated product thereof.

  Examples of styrene block copolymers include styrene ABA block copolymers (triblock copolymers) such as styrene / butadiene / styrene copolymers (SBS) and styrene / isoprene / styrene copolymers (SIS). ); Styrenic ABAB type block copolymer (tetrablock copolymer) such as styrene / butadiene / styrene / butadiene copolymer (SBSB), styrene / isoprene / styrene / isoprene copolymer (SISI); styrene / butadiene・ Styrene-based ABABA block copolymer (pentablock copolymer) such as styrene / butadiene / styrene copolymer (SBSBS), styrene / isoprene / styrene / isoprene / styrene copolymer (SISIS); Styrene group having repeating units Click copolymers; and the like.

  Examples of hydrogenated styrenic block copolymers include styrene / ethylene-butylene copolymer / styrene copolymer (SEBS), styrene / ethylene-propylene copolymer / styrene copolymer (SEPS), and styrene. -Ethylene-butylene copolymer-Styrene-ethylene-butylene copolymer copolymer (SEBSEB);

  Only one type of styrenic thermoplastic elastomer may be used, or two or more types may be used.

  When the styrenic thermoplastic elastomer is a styrenic block copolymer or a hydrogenated product thereof, the styrene block content in the styrenic thermoplastic elastomer is preferably 5 wt% to 40 wt%, more preferably 7 wt%. % To 30% by weight, more preferably 9% to 20% by weight. When the styrene block content is reduced, adhesive residue due to insufficient cohesive force of the adhesive layer may be easily generated. When the styrene block content is increased, the pressure-sensitive adhesive layer becomes hard, and there is a possibility that good adhesion to a rough surface cannot be obtained.

  As the styrene-based thermoplastic elastomer, hydrogenation of a styrene-based block copolymer having a repeating structure (ABA type, ABAB type, ABABA type, etc.) more than a triblock copolymer composed of styrene (A) and butadiene (B). Goods (SEBS, SEBSEB, SEBSEBS, etc.) are preferred. By adopting such a styrenic thermoplastic elastomer, the adhesive force in the state of being applied to the adherend can be increased more moderately, while the adhesive force when peeling off after being attached to the adherend is more appropriate. Therefore, it can be peeled off from the adherend more easily with a slight force, and the increase in adhesive strength when exposed to an environmental load for long-term storage at relatively high temperatures is further suppressed. it can.

  Hydrogenated product of styrene-based block copolymer in which the styrene-based thermoplastic elastomer has a repetitive structure (ABA type, ABAB type, ABABA type, etc.) of a triblock copolymer or more composed of styrene (A) and butadiene (B) (SEBS, SEBSEB, SEBSEBS, etc.) The proportion of the butylene structure in the ethylene-butylene copolymer block is preferably 60% by weight or more, more preferably 70% by weight or more, and even more preferably 75. % By weight or more. When the proportion of the butylene structure in the ethylene-butylene copolymer block falls within the above range, the adhesive force in the state of application to the adherend can be increased more moderately, on the other hand, after being attached to the adherend Adhesive strength at the time of peeling is a more appropriate size, therefore, it can be peeled off from the adherend more easily with a slight force, and further exposed to the environmental load of long-term storage at relatively high temperatures. In this case, the increase in adhesive strength can be further suppressed. The proportion of the butylene structure in the ethylene-butylene copolymer block is preferably 90% by weight or less.

  The pressure-sensitive adhesive layer may contain other styrenic thermoplastic elastomers within the range that does not impair the object of the present invention for the purpose of adjusting the adhesiveness.

  Other styrene thermoplastic elastomers include styrene block copolymers other than those described above; styrene / butadiene copolymers (SB), styrene / isoprene copolymers (SI), and copolymers of styrene / ethylene-butylene copolymers. AB block polymers such as polymers (SEB) and styrene / ethylene-propylene copolymer (SEP); styrene random copolymers such as styrene / butadiene rubber (SBR); styrene / ethylene-butylene copolymer Examples thereof include ABC type styrene / olefin crystal block polymers such as a polymer / olefin crystal copolymer (SEBC); hydrogenated products thereof.

  In the formation of the adhesive layer, for the purpose of controlling adhesive properties, etc., for example, softening agents, tackifiers, polyolefin resins such as those used for the base material layer, silicone polymers, liquid acrylic copolymers are used. Polymer, Phosphate ester compound, Anti-aging agent, Light stabilizer, UV absorber, Surface lubricant, Leveling agent, Plasticizer, Low molecular weight polymer, Antioxidant, Corrosion inhibitor, Polymerization inhibitor, Silane cup Additives such as ring agents, inorganic and organic fillers (for example, calcium oxide, magnesium oxide, silica, zinc oxide, titanium oxide, etc.), metal powder, colorants, pigments, heat stabilizers, etc. may be added as appropriate. it can.

  For example, corona discharge treatment, ultraviolet irradiation treatment, flame treatment, plasma treatment, sputter etching treatment, and other surface treatments for the purpose of adhesion control and pasting workability are performed on the adhesive layer surface as necessary. You can also.

  The formulation of the tackifier is effective for improving the adhesive strength. However, the blending amount of the tackifier is appropriately determined according to the adherend to which the surface protective sheet is applied in order to avoid the occurrence of the adhesive residue problem due to the decrease in cohesive force. The compounding amount of the tackifier is preferably 80% by weight or less, more preferably 40% by weight or less, and further preferably 20% by weight or less with respect to the base polymer of the adhesive layer. In addition, when the adherend to which the surface protective sheet is applied is a metal plate, it is preferable not to add a tackifier when forming the adhesive layer.

  Examples of the tackifier include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymer systems and alicyclic copolymers, and coumarone-indene resins. Terpene resins, terpene phenol resins, rosin resins such as polymerized rosin, (alkyl) phenol resins, xylene resins, hydrogenated products thereof, etc. Things can be used without any particular restrictions. Only one type of tackifier may be used, or two or more types may be used. Among these tackifiers, hydrogenated tackifiers are preferable from the viewpoint of peelability and weather resistance. In addition, what is marketed as a blend with an olefin resin can also be used for a tackifier.

  The blending of the softener is effective for improving the adhesive strength. Examples of the softening agent include low molecular weight diene polymers, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, and derivatives thereof. Examples of such derivatives include those having an OH group or a COOH group at one or both ends, specifically hydrogenated polybutadiene diol, hydrogenated polybutadiene monool, hydrogenated polyisoprene diol, water Examples thereof include polyisoprene monool. In particular, hydrogenated products of diene polymers such as hydrogenated polybutadiene and hydrogenated polyisoprene, olefinic softeners, and the like are preferable for the purpose of suppressing the improvement in adhesiveness to the adherend. As such a softening agent, specifically, trade name “Kuraprene LIR-200” manufactured by Kuraray Co., Ltd. is available. These softeners may be used alone or in combination of two or more.

  The molecular weight of the softening agent can be appropriately set to any appropriate amount, but if the molecular weight is small, there is a risk of causing material transfer or heavy peeling from the adhesive layer to the adherend, while the molecular weight is large. Since there exists a tendency for it to become scarce at the improvement effect of adhesive force, the number average molecular weight of a softener becomes like this. Preferably it is 5000-100,000, More preferably, it is 10,000-50,000.

  When using a softener, the amount added can be appropriately set to any appropriate amount. However, as the amount added increases, the adhesive residue tends to increase at high temperatures and when exposed outdoors. On the other hand, it is preferably 100% by weight or less, more preferably 60% by weight or less, and still more preferably 40% by weight or less. In addition, when the adherend to which the surface protective sheet is applied is a metal plate, it is preferable not to add a softener when forming the adhesive layer.

  A polyolefin-based resin may be added to the adhesive layer for the purpose of suppressing an increase in adhesive force. Examples of the polyolefin resin can be the same as those used for forming the base material layer. This polyolefin resin may be only one kind or two or more kinds. The blending amount of the polyolefin resin is preferably 50% by weight or less, more preferably 30% by weight or less, and further preferably 20% by weight or less with respect to the base polymer of the adhesive layer.

  If necessary, a separator or the like can be temporarily attached to the adhesive layer until it is put to practical use.

  The method for producing the surface protective sheet of the present invention is preferably produced by integrally forming the base material layer and the adhesive layer by coextrusion molding. Thereby, the surface protection sheet of the laminated structure which has predetermined | prescribed thickness can be manufactured highly efficiently and cheaply. As the coextrusion molding, any appropriate coextrusion molding generally used for production of films, sheets and the like can be adopted. As the coextrusion molding, for example, an inflation method, a coextrusion T-die method, or the like can be adopted.

  According to the co-extrusion molding, the outermost surface on the opposite side of the adhesive layer of the base material layer and the adhesive layer are not in contact with each other in the melt-heated state. There is no production of by-products and no transfer of the by-products to the adhesive layer, and excellent unwinding properties are exhibited, and contamination of the adhesive layer surface can be suppressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all.

(Density measurement)
The density (g / cm ³ ) of the resin was a value measured according to ISO 1183.

(Measurement of surface roughness Ra)
The surface protection sheet was affixed to the SUS430BA plate by a reciprocating 2 kg roller. The surface roughness Ra (μm) of the attached surface protective sheet on the white layer side was measured according to JIS B0601 (2001) at a stylus tip diameter of 2 μm, a measurement length of 4 mm, and a cutoff of 0.8 mm.

(Measurement of 60 degree gloss)
A 60 ° angle reflectance was measured using a micro trigloss manufactured by Gardner.

(Appearance evaluation)
The surface protective sheet was affixed to the SUS430BA plate by a reciprocating 2 kg roller, and observed visually from the white layer side of the adhered surface protective sheet.
The case where bubbles or foreign matters were noticeably observed at the time of pasting was rated as x, and the case where bubbles or foreign matters were hardly seen due to roughening or low gloss of the surface was marked as ◯.

(Coextrusion molding conditions)
In Examples and Comparative Examples, molding was performed by an inflation method according to the following melting temperature conditions.
Base material layer: 165 ° C
Adhesive layer: 165 ° C
Coextrusion temperature: 165 ° C

[Example 1]
Low-density polyethylene (Nippon polyethylene, trade name: Novatec LD LF440C, density = 0.923 g / cm ³ , MFR = 2.8 g / 10 min, autoclaved polyethylene) 82% by weight, white pigment (titanium oxide, manufactured by Dupont, product) Name: Ti-Pure R103) 18 wt% was blended to obtain a white layer forming material.
Next, 95% by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), carbon black MB (manufactured by Sumika Color, trade name: black SPEMB-865, carbon content) 20%) was blended with a blend of 5% by weight to obtain a black layer forming material.
Furthermore, SEBS (hydrogenated SEBS, styrene content = 15% by weight, manufactured by JSR, trade name: Dynalon 8600P) 82% by weight, tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan, trade name: Imabu P140) ) 18 wt% was blended to obtain an adhesive layer forming material.
Using the white layer forming material, black layer forming material, and adhesive layer forming material obtained above, the surface of a three-layer structure (white layer / black layer / adhesive layer) by coextrusion molding by the inflation method A protective sheet (1) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

[Example 2]
As a white layer forming material, low-density polyethylene (manufactured by Tosoh, trade name: Petrocene 172, density = 0.920 g / cm ³ , MFR = 0.3 g / 10 min, autoclave polyethylene) 82% by weight, white pigment (titanium oxide) , Manufactured by Dupont, trade name: Ti-Pure R103) 3 layer structure (white layer / black), except that a white layer forming material obtained by blending 18% by weight was used. A surface protective sheet (2) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 3
As white-type layer forming material, low-density polyethylene (trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) manufactured by Tosoh, 73% by weight, long chain alkyl type Back treatment agent (Ashio Sangyo Co., Ltd., ashioresin RA95HS (fully saponified polyvinyl octadecylcarbamate release agent)) 9 wt%, white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) 18 wt% The surface protective sheet (3) (thickness: 3 layer structure (white layer / black layer / adhesive layer)) was carried out in the same manner as in Example 1 except that the white layer-forming material thus obtained was used. White layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 1.

Example 4
Low-density polyethylene (manufactured by Nippon Polyethylene, trade name: Novatec LD LC720, density = 0.922 g / cm ³ , MFR = 9.4 g / 10 min, autoclaved polyethylene) 47% by weight, white density layer forming material, low-density polyethylene (Product name: Petrocene 172, density = 0.920 g / cm ³ , MFR = 0.3 g / 10 min, autoclaved polyethylene) 35% by weight, white pigment (titanium oxide, manufactured by Dupont, product name: Ti-Pure R103) A surface protective sheet having a three-layer structure (white layer / black layer / adhesive layer) was carried out in the same manner as in Example 1 except that the white layer-forming material obtained by blending 18% by weight was used. (4) (Thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 5
As a white layer forming material, low-density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 32% by weight, low-density polyethylene ( Product name: Petrocene 172, density = 0.920 g / cm ³ , MFR = 0.3 g / 10 min, autoclave polyethylene 50% by weight, white pigment (titanium oxide, manufactured by Dupont, product name: Ti-Pure R103 ) A surface protective sheet having a three-layer structure (white layer / black layer / adhesive layer) was carried out in the same manner as in Example 1 except that the white layer-forming material obtained by blending 18% by weight was used. 5) (Thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 6
Low-density polyethylene (made by Nippon Polyethylene, trade name: Novatec LD LF440C, density = 0.923 g / cm ³ , MFR = 2.8 g / 10 min, autoclave polyethylene) 47% by weight, low-density polyethylene (made by Tosoh, trade name: Petrocene 172, density = 0.920 g / cm ³ , MFR = 0.3 g / 10 min, autoclaved polyethylene 35% by weight, white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) 18% by weight The surface protective sheet (6) (thickness: 3 layer structure (white layer / black layer / adhesive layer)) was carried out in the same manner as in Example 1 except that the white layer forming material obtained in this manner was used. White layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 1.

Example 7
As a white layer forming material, low-density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 77% by weight, acrylic beads MB ( Made by Sumika Color Co., Ltd., trade name: Kinoplus EMB-Y-1231, acrylic beads concentration 5%) 5% by weight, white pigment (titanium oxide, made by Dupont, trade name: Ti-Pure R103) 18% by weight A surface protective sheet (7) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer) was carried out in the same manner as in Example 1 except that the obtained white layer forming material was used. / Black type layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

Example 8
As a white layer forming material, low-density polyethylene (trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) manufactured by Tosoh, 72% by weight, acrylic beads MB ( Made by Sumika Color Co., Ltd., trade name: Kinoplus EMB-Y-1231, acrylic beads concentration 5%) 10% by weight, white pigment (titanium oxide, made by DuPont, trade name: Ti-Pure R103) 18% by weight A surface protective sheet (8) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer) was carried out in the same manner as in Example 1 except that the obtained white layer forming material was used. / Black type layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

Example 9
As a white layer forming material, low-density polyethylene (manufactured by Nippon Polyethylene, trade name: Novatec LD LF440C, density = 0.923 g / cm ³ , MFR = 2.8 g / 10 min, autoclave polyethylene) 77% by weight, acrylic beads MB (Sumika Color Co., Ltd., trade name: Kinoplus EMB-Y-1231, acrylic bead concentration 5%) 5% by weight, white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) 18% by weight A surface protective sheet (9) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer) was carried out in the same manner as in Example 1 except that the obtained white layer forming material was used. Layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

Example 10
As the white layer forming material, low-density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 72% by weight, polypropylene (Nippon Polypro) Except for using white layer forming material obtained by blending 10% by weight, Novatec PP EG8B), 18% by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) 1. Surface protective sheet (10) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) Obtained.
The results are shown in Table 2.

Example 11
As a white layer forming material, 62% by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular method polyethylene), polypropylene (Nippon Polypro) Except for using a white layer forming material obtained by blending 20% by weight, Novatec PP EG8B), 18% by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) 1. Surface protection sheet (11) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) Obtained.
The results are shown in Table 2.

Example 12
As a white layer forming material, low-density polyethylene (manufactured by Nippon Polyethylene, trade name: Novatec LD LC720, density = 0.922 g / cm ³ , MFR = 9.4 g / 10 min, autoclaved polyethylene) 62% by weight, ethylene / acetic acid It was obtained by blending 20% by weight of a vinyl copolymer (Mitsui / Dupont Polychemical, trade name: Everflex EV360RC) and 18% by weight of a white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103). A surface protective sheet (12) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer / black) was carried out in the same manner as in Example 1 except that the white layer forming material was used. System layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

[Comparative Example 1]
Low-density polyethylene (trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 82% by weight as white layer forming material, white pigment (oxidized) Titanium, manufactured by Dupont, trade name: Ti-Pure R103) Except for using a white layer-forming material obtained by blending 18% by weight, a three-layer structure (white layer / A surface protective sheet (C1) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) of black layer / adhesive layer was obtained.
The results are shown in Table 3.

[Comparative Example 2]
As a white layer forming material, low-density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 72% by weight, low-density polyethylene ( Product name: Petrocene 172, density = 0.920 g / cm ³ , MFR = 0.3 g / 10 min, autoclave polyethylene 10% by weight, white pigment (titanium oxide, manufactured by Dupont, product name: Ti-Pure R103 ) A surface protective sheet having a three-layer structure (white layer / black layer / adhesive layer) was carried out in the same manner as in Example 1 except that the white layer-forming material obtained by blending 18% by weight was used. C2) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 3.

[Comparative Example 3]
As a white layer forming material, low-density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 62% by weight, low-density polyethylene ( Product name: Petrocene 172, density = 0.920 g / cm ³ , MFR = 0.3 g / 10 min, autoclave polyethylene 20% by weight, white pigment (titanium oxide, manufactured by Dupont, product name: Ti-Pure R103 ) A surface protective sheet having a three-layer structure (white layer / black layer / adhesive layer) was carried out in the same manner as in Example 1 except that the white layer-forming material obtained by blending 18% by weight was used. C3) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 3.

[Comparative Example 4]
As a white layer forming material, low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular polyethylene) 72% by weight, metallocene polypropylene (Japan) Other than using a white layer-forming material obtained by blending 10% by weight of Polypro, trade name: Wintech WFX6) and 18% by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) Was carried out in the same manner as in Example 1, and the surface protective sheet (C4) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer / black layer / adhesive layer = 20 μm / 35 μm) / 5 μm).
The results are shown in Table 3.

[Comparative Example 5]
Low-density polyethylene (product name: Petrocene 186R, density = 0.924 g / cm ³ , MFR = 3.0 g / 10 min, tubular method polyethylene) 72% by weight, ethylene / vinyl acetate as white layer forming material White obtained by blending 10% by weight of a copolymer (Mitsui / DuPont Polychemical, trade name: Everflex EV360RC) and 18% by weight of a white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) A surface protective sheet (C5) having a three-layer structure (white layer / black layer / adhesive layer) (thickness: white layer / black layer) was carried out in the same manner as in Example 1 except that the layer forming material was used. Layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 3.

  From Table 1, Table 2, and Table 3, the surface protective sheet of the present invention is a surface protective sheet including a base material layer and an adhesive layer, and the outermost surface of the base material layer is effectively roughened to form a mat. It can be seen that the appearance and tactile sensation are not impaired even if foreign matter is present.

  The surface protective sheet of the present invention includes, for example, a metal plate, a paint plate, an aluminum sash, a resin plate, a decorative steel plate, a vinyl chloride laminated steel plate, a glass plate and other members, a polarizing film, an optical member such as a liquid crystal panel, and an electronic member. When transporting, processing, curing, etc., it is used for applications such as sticking to the surface for protection.

DESCRIPTION OF SYMBOLS 100 Surface protection sheet 10 Adhesion layer 20 Base material layer 21 White type layer 22 Black type layer

Claims (12)

A surface protective sheet comprising a base material layer and an adhesive layer,
The base material layer and the adhesive layer are integrally formed by coextrusion molding,
The surface roughness Ra of the outermost surface of the base material layer is 0.10 μm to 0.60 μm,
The 60 degree gloss of the outermost surface of the base material layer is 20.0 to 71.5.
Surface protection sheet.   The surface protective sheet according to claim 1, wherein the surface roughness Ra is 0.20 μm to 0.60 μm, and the 60-degree gloss is 20.0 to 65.0.   The surface protection sheet of Claim 1 or 2 in which the said base material layer contains polyolefin resin as a main component.   The surface protection sheet in any one of Claim 1 to 3 in which the said base material layer contains a white type | system | group layer.   The surface protection sheet according to claim 4, wherein the white layer includes a polyethylene resin as a main component.   The surface protection sheet according to claim 5, wherein the polyethylene-based resin contains autoclaved polyethylene as a main component.   The surface protection sheet according to claim 5 or 6 in which said white system layer further contains resin different from said polyethylene system resin.   The surface protective sheet according to claim 7, wherein the resin different from the polyethylene resin is at least one selected from a polypropylene resin and an ethylene / vinyl acetate copolymer.   The surface protection sheet in any one of Claim 4 to 8 in which the said white type | system | group layer contains particle | grains.   The surface protection sheet in any one of Claim 1-9 in which the said base material layer contains a black-type layer.   The surface protection sheet according to claim 10, wherein the black layer includes a polyethylene resin as a main component. The surface protection sheet in any one of Claim 1-11 in which the said adhesion layer contains a styrene-type thermoplastic elastomer.

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