JP2014100884A - Surface protection sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface protection sheet having a substrate layer with a rough-surfaced outermost surface, which is sufficient to make a foreign substance inconspicuous even if enclosed between the surface protection sheet and an adherend, the surface protection sheet capable of exerting sufficient and appropriate adhesive strength either on a smooth-surfaced adherend or a rough-surfaced adherend.SOLUTION: A surface protection sheet includes a white-based substrate layer, a black-based substrate layer and an adhesive layer in this order. The white-based substrate layer is an outermost layer. Surface roughness Ra of an outermost surface of the white-based substrate layer is 0.30 μm or more, and surface glossiness at 60° gloss of the outermost surface of the white-based substrate layer is 65 or lower.

Description

  The present invention relates to a surface protective sheet. Specifically, the present invention relates to a surface protective sheet including a white base material layer, a black base material layer, and an adhesive layer in this order, and the white base material layer is an outermost 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). .

  The outermost surface of the base material layer in the surface protective sheet may be preferably smooth from the viewpoint of the appearance. However, if the outermost surface of the base material layer in the surface protection sheet is too smooth, the foreign matter existing between the surface protection sheet and the adherend becomes noticeable, and the tactile sensation is deteriorated. This causes a problem that the accuracy of the image quality decreases, which also affects productivity.

  Moreover, the conventional surface protection sheet does not have a sufficient and moderately high adhesive force in the state of being attached to the adherend. For this reason, when processing the adherend to which the conventional surface protective sheet is attached, there is a problem that a part of the surface protective sheet is peeled off. For example, the adhesive strength at low-speed peeling at 23 ° C. may not be sufficiently and moderately high, or the similar adhesive strength after 1 week after sticking may not be sufficiently and moderately high.

  Furthermore, the conventional surface protection sheet has a problem of low adhesion to a rough surface. For example, when the surface is attached to a SUS hairline plate whose hairline has been processed, there is a problem that sufficient and appropriate adhesiveness cannot be exhibited, such as peeling or tearing during processing.

JP-A-61-103975

  The problem of the present invention is that the outermost surface of the base material layer is roughened to such an extent that foreign matter is present between the surface protective sheet and the adherend, and the adherend is smooth. It is an object of the present invention to provide a surface protective sheet that can exhibit a sufficient and appropriate adhesive force even with a rough adherend.

The surface protective sheet of the present invention is
A surface protective sheet comprising a white base layer, a black base layer and an adhesive layer in this order,
The white base layer is the outermost layer;
The surface roughness Ra of the outermost surface of the white base layer is 0.30 μm or more,
The surface glossiness of 60 ° gloss on the outermost surface of the white base material layer is 65 or less.

  In a preferred embodiment, inorganic particles are contained in the white base material layer.

  In preferable embodiment, the content rate of the inorganic particle in the said white-type base material layer is 2 weight%-8 weight%.

  In preferable embodiment, the average particle diameter of the said inorganic particle is 5 micrometers-10 micrometers.

In a preferred embodiment, the inorganic particles are at least one selected from SiO ₂ and CaCO ₃ .

  In a preferred embodiment, the white base material layer, the black base material layer, and the adhesive layer are integrally formed by coextrusion molding.

  In preferable embodiment, the said white-type base material layer contains a polyethylene-type resin as a main component.

  In preferable embodiment, the said polyethylene-type resin contains a low density polyethylene.

  In preferable embodiment, the said black-type base material layer contains a polyethylene-type resin as a main component.

  In preferable embodiment, the said polyethylene-type resin contains a low density polyethylene.

  In preferable embodiment, the said polyethylene-type resin contains a linear low density polyethylene.

  In a preferred embodiment, the surface protective sheet of the present invention has an initial adhesive strength to a SUS430BA plate at 23 ° C. of 1.0 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min.

  In a preferred embodiment, the surface protective sheet of the present invention has an adhesive strength of one week after sticking to a SUS430BA plate at 23 ° C. at 2.0 ° N / 180 ° peel at a tensile rate of 0.3 m / min. It is 20 mm or more.

  In a preferred embodiment, the surface protective sheet of the present invention has an initial adhesive force of SUS304 hairline plate at 23 ° C. of 1.5 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min.

  In a preferred embodiment, the surface protective sheet of the present invention has an adhesive strength of 1 week after application to a SUS304 hairline plate at 23 ° C. at 2.0 N at 180 ° peel at a tensile speed of 0.3 m / min. / 20 mm or more.

  In a preferred embodiment, the surface protective sheet of the present invention has a breaking strength of 20 N / 20 mm or more.

  In a preferred embodiment, the surface protective sheet of the present invention has an elongation at break of 200% or more.

  According to the present invention, the outermost surface of the base material layer is roughened to such an extent that foreign matter is present between the surface protective sheet and the adherend, and the adherend is smooth. Even if it is a rough adherend, the surface protection sheet which can express sufficient and moderate adhesive force can be provided.

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 white base material layer, a black base material layer, and an adhesive layer in this order. One of the outermost layers of the surface protective sheet of the present invention is a white base material 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 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 adjusting the total thickness of the surface protective sheet of the present invention within the above range, it can be a surface protective sheet having excellent handleability and sufficient mechanical strength.

  The white base material 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, Preferably it is 80% or more, Most preferably, it is 85% or more. The white base 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 base material layer contains a white pigment, the content is preferably 0.1% by weight to 50% by weight and more preferably 1% with respect to the resin component forming the white base material layer. % By weight to 40% by weight, more preferably 2% by weight to 30% by weight. By adjusting the content ratio of the white pigment to the resin component forming the white base material layer within the above range, a surface protective sheet having excellent weather resistance can be obtained, and extrudability and other moldability are also excellent.

The resin component forming the white base layer is preferably a polyolefin resin. Specific examples of the polyolefin resin include high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene, a propylene component, and an ethylene component. Propylene resin, 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 And ethylene / vinyl alcohol copolymer. The resin component forming the white base material layer is more preferably a propylene polymer or an ethylene polymer. Specific examples of the resin component forming the white base layer include homopolypropylene, block polypropylene, random polypropylene, high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low density. Polyethylene (LLDPE) is preferred. The white base material layer preferably contains a polyethylene resin as a main component. The density of the polyethylene resin 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 , and still more preferably 0 .880 g / cm ^{3 to} 0.915 g / cm ³ . When the white base layer contains a polyethylene resin as a main component, the white base layer can have heat resistance, solvent resistance, and flexibility, and the surface protection sheet of the present invention can be easily rolled. It becomes possible to wind up. When the white base material layer contains a polyethylene resin as a main component, the polyethylene resin preferably contains low density polyethylene. When the polyethylene resin contains low-density polyethylene, the white base layer can have sufficient heat resistance, solvent resistance, and flexibility, and the surface protective sheet of the present invention can be more easily rolled. It can be wound up.

  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.

  The content of the polyolefin-based resin in the white base layer is preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and particularly preferably 85% by weight. Or more, and most preferably 90% by weight or more. Such polyolefin resin may use only 1 type, and may use 2 or more types.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of a white-type base material 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 base material layer is a layer showing a black color tone. The black base 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 a black base material layer contains a black pigment, the content ratio is preferably 0.01% by weight to 10% by weight, and more preferably 0.1% with respect to the resin component forming the black base layer. % By weight to 5% by weight, more preferably 0.5% by weight to 3% by weight. By adjusting the content ratio of the black pigment to the resin component forming the black base layer within the above range, a surface protective sheet excellent in weather resistance can be obtained, and extrudability and other moldability are also excellent.

The resin component forming the black base layer is preferably a polyolefin resin. Specific examples of the polyolefin resin include high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene, a propylene component, and an ethylene component. Propylene resin, 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 And ethylene / vinyl alcohol copolymer. The resin component forming the black base layer is more preferably a propylene polymer or an ethylene polymer. Specific examples of the resin component forming the black base layer include homopolypropylene, block polypropylene, random polypropylene, high density polyethylene (HDPE), medium density polyethylene, low density polyethylene (LDPE), and linear low density. Polyethylene (LLDPE) is preferred. The black base material layer preferably contains a polyethylene resin as a main component. The density of the polyethylene resin 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 , and still more preferably 0 .880 g / cm ^{3 to} 0.915 g / cm ³ . When the black base material layer contains a polyethylene resin as a main component, the base material 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 shape. It becomes possible to take. When the black base material 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-based resin contains at least one selected from low-density polyethylene and linear low-density polyethylene, the black base material layer can sufficiently have heat resistance, solvent resistance, and flexibility, It becomes possible to wind the surface protection sheet of the present invention into a roll more easily.

  The content of the polyolefin-based resin in the black base layer is preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and particularly preferably 85% by weight. Or more, and most preferably 90% by weight or more. Such polyolefin resin may use only 1 type, and may use 2 or more types.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of a black base material 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 white base material layer preferably contains inorganic particles. Such inorganic particles can be applied as long as they are generally known as inorganic particles, but in order to sufficiently exhibit the effects of the present invention, at least selected from SiO ₂ and CaCO ₃ is preferable. One type.

  FIG. 1 is a cross-sectional view schematically showing a configuration example of the surface protective sheet of the present invention when inorganic particles are contained in a white base material layer. In FIG. 1, one example of a structure in case the surface protection sheet 100 of this invention has a laminated structure of "white base material layer 21 / black base material layer 22 / adhesion layer 10" is shown typically. In the white base material layer 21, inorganic particles 30 are included.

  When inorganic particles are contained in the white base material layer, the content ratio of the inorganic particles in the white base material layer is preferably 2% by weight to 8% by weight, more preferably 2% by weight to 7% by weight. More preferably, it is 2 to 6% by weight. By adjusting the content ratio of the inorganic particles in the white base layer within this range, the outermost base layer is not noticeable even if foreign matter is present between the surface protection sheet and the adherend. The surface can be sufficiently roughened. When the content of the inorganic particles in the white base material layer is less than 2% by weight, and when the outermost surface of the base material layer is observed when foreign matter is present between the surface protection sheet and the adherend There is a risk that foreign objects will be noticeable. When the content of the inorganic particles in the white base layer exceeds 8% by weight, not only poor dispersion of the white pigment and falling off of the inorganic particles are likely to occur, but also the strength properties of the film are lowered, and the adherend is processed. At times, the film may be broken and the damage to the adherend may occur.

  When inorganic particles are contained in the white base material layer, the average particle diameter of the inorganic particles is preferably 5 μm to 10 μm, more preferably 5 μm to 9 μm, and further preferably 6 μm to 8 μm. By adjusting the average particle diameter of the inorganic particles within this range, the outermost surface of the base material layer is sufficiently roughened to such an extent that no foreign matter is present between the surface protective sheet and the adherend. Can be When the average particle size of the inorganic particles is less than 5 μm, if foreign matter is present between the surface protective sheet and the adherend, the foreign matter may be noticeable when the outermost surface of the base material layer is observed. . When the average particle diameter of the inorganic particles exceeds 10 μm, not only is the white pigment poorly dispersed or the inorganic particles are likely to fall off, but the strength properties of the film are lowered, and the film breaks during the processing of the adherend and the accompanying deposition. May cause damage to the body.

  Unlike the white base material layer, the black base material layer preferably contains no inorganic particles. The content ratio of the inorganic particles in the black base layer is preferably 1% by weight or less, more preferably 0.1% by weight or less, and further preferably substantially 0% by weight. By adjusting the content ratio of the inorganic particles in the black base layer within this range, the outermost base layer is not noticeable even if foreign matter is present between the surface protection sheet and the adherend. The surface can be sufficiently roughened.

  The white base material layer and the black 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.

  The white base material layer and the black base material layer preferably contain a light stabilizer. When the white base layer or the black base layer contains a light stabilizer, sufficient weather resistance can be imparted to the surface protective sheet of the present invention.

  Any appropriate light stabilizer can be adopted as the light stabilizer as long as the effects of the present invention are not impaired. As such a light stabilizer, for example, a hindered amine light stabilizer (HALS) is preferably exemplified.

  When the white base layer or the black base layer contains a light stabilizer, the content ratio of the light stabilizer is preferably 0.10% by weight with respect to the total weight of the surface protective sheet of the present invention. More preferably, it is 0.20 wt% to 0.64 wt%, more preferably 0.30 wt% to 0.60 wt%, and particularly preferably 0.34 wt% to 0.55 wt%. % By weight. When the white base material layer or the black base material layer contains a light stabilizer, if the content ratio of the light stabilizer is adjusted within the above range with respect to the weight of the entire surface protective sheet of the present invention, More sufficient weather resistance can be imparted to the surface protective sheet of the invention.

  A back surface treatment may be performed on the outermost surface of the white 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 processing such as embossing and uneven processing, a method of containing a fatty acid derivative, and the like. Only one kind of such fatty acid derivative may be used, or two or more kinds thereof may be used.

  When the white base layer contains a fatty acid derivative, the content ratio of the fatty acid derivative in the white base layer is preferably 0.05% by weight to 1.00% with respect to the resin component in the white base layer. % By weight, more preferably 0.10% by weight to 0.90% by weight, and still more preferably 0.30% by weight to 0.80% by weight. If the content ratio of the fatty acid derivative in the white base layer is adjusted within the above range with respect to the resin component in the white base layer, the roll-shaped surface protective sheet of the present invention can be easily rewound. This makes it possible to sufficiently exhibit the mold release effect and sufficiently suppress contamination of the fatty acid derivative due to bleeding.

  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, ethylene bis behenate amide, N, N-dioleyl adipate amide, N-stearyl- N-stearyl-N′-stearylamide such as N′-stearyl urea, zinc stearate and the like can be mentioned.

  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, ethylene bis behenic acid amide, N-stearyl-N′-stearyl acid amide. It is a seed.

  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 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 adjusting 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 protection has sufficient mechanical strength. A sheet can be obtained.

  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.

  Preferred examples of the styrenic thermoplastic elastomer include hydrogenated styrene / butadiene rubber (HSBR), a styrene block copolymer, and 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.

  The styrene content in the styrenic thermoplastic elastomer (styrene block content in the case of a styrene block copolymer) is preferably 0.5 wt% to 25 wt%, more preferably 1 wt% to 20 wt%. More preferably, it is 2 to 18% by weight, and particularly preferably 3 to 15% by weight. By adjusting the styrene content within the above range, the surface protective sheet of the present invention exhibits a sufficient and appropriate adhesive force regardless of whether the surface is a smooth adherend or a rough adherend. Can do. When the styrene content decreases, there is a risk that adhesive residue due to insufficient cohesive force of the adhesive layer is likely to occur. When the styrene content increases, 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, it is possible to more sufficiently and appropriately express the adhesive force in the state of being applied to the adherend, while the adhesive force when peeling off after being attached to the adherend is improved. More adequate and moderate size. Therefore, it can be easily peeled off from the adherend with moderately slight force. Furthermore, the adhesive strength when exposed to the environmental load of long-term storage is fully and moderately expressed. 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. By adjusting the proportion of the butylene structure in the ethylene-butylene copolymer block within the above range, it is possible to more adequately and appropriately express the adhesive force in the state of sticking to the adherend, while on the adherend. Adhesive strength when peeling after being applied is more sufficient and moderate in size, and therefore, it can be peeled off from the adherend more easily with moderately slight force, and further exposed to the environmental load of long-term storage. In this case, the adhesive strength can be expressed sufficiently and moderately. 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.

  The softening point of the tackifier is preferably 100 ° C. or higher, more preferably 105 ° C. or higher, still more preferably 110 ° C. or higher, and particularly preferably 115 ° C. or higher. The upper limit value of the softening point is, for example, preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower. By adjusting the softening point of the tackifier within the above range, the surface protective sheet of the present invention is sufficient and appropriate for both a smooth surface and a rough surface. Adhesive strength can be further developed.

  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, particularly C5 hydrogenated aromatic petroleum resins, are preferable from the viewpoints 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.

  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.

  In the surface protective sheet of the present invention, the outermost surface roughness Ra of the white base layer is 0.30 μm or more, preferably 0.30 μm to 1.0 μm, more preferably 0.30 μm to 0. .80 μm, particularly preferably 0.30 μm to 0.60 μm. By adjusting the surface roughness Ra of the outermost surface of the white base layer in the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention is provided between the surface protective sheet and the adherend. The outermost surface of the base material layer can be roughened to such an extent that foreign matter is not noticeable. A method for measuring the surface roughness Ra will be described later.

  In the surface protective sheet of the present invention, the 60 ° gloss surface glossiness of the outermost surface of the white base layer is 65 or less, preferably 20 to 65, more preferably 25 to 60, and particularly preferably. Is 25-55. By adjusting the 60 ° gloss surface glossiness of the outermost surface of the white base layer in the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention comprises a surface protective sheet, an adherend, Even if foreign matter is present between the two, it may be as inconspicuous as possible. A method for measuring the surface gloss will be described later.

  In the surface protective sheet of the present invention, the initial adhesive strength to the SUS430BA plate at 23 ° C. is preferably 1.0 N / 20 mm or more, more preferably 1.0 N at 180 ° peel at a tensile speed of 0.3 m / min. / 20 mm to 3.0 N / 20 mm, more preferably 1.2 N / 20 mm to 2.8 N / 20 mm, and particularly preferably 1.4 N / 20 mm to 2.5 N / 20 mm. By adjusting the initial adhesive strength of the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention can exhibit a sufficiently high and moderate adhesive strength at low speed peeling at room temperature. In addition, the measuring method of the various adhesive force with respect to a SUS430BA board is mentioned later.

  In the surface protective sheet of the present invention, the adhesive strength after 1 week to the SUS430BA plate at 23 ° C. is preferably 2.0 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min. More preferably, it is 2.0N / 20mm-4.0N / 20mm, More preferably, it is 2.0N / 20mm-3.8N / 20mm, Most preferably, it is 2.0N / 20mm-3.5N / 20mm is there. By adjusting the adhesive strength of the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention is sufficiently and moderately high in low-speed peeling when exposed to an environmental load for long-term storage. Can be expressed. In addition, the measuring method of the various adhesive force with respect to a SUS430BA board is mentioned later.

  In the surface protective sheet of the present invention, the initial adhesive force to the SUS304 hairline plate at 23 ° C. is preferably 1.5 N / 20 mm or more, more preferably at 1.80 N peel at a tensile speed of 0.3 m / min. 5N / 20mm to 3.0N / 20mm, more preferably 1.5N / 20mm to 2.8N / 20mm, and particularly preferably 1.5N / 20mm to 2.5N / 20mm. By adjusting the initial adhesive strength of the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention is sufficient even for an adherend having a rough surface at low speed peeling at room temperature. Moreover, moderately high adhesive force can be expressed. In addition, the measuring method of the various adhesive force with respect to a SUS304 hairline board is mentioned later.

  The surface protective sheet of the present invention has an adhesive force of 1 week after sticking to a SUS304 hairline board at 23 ° C., preferably at 2.0 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min. More preferably 2.0 N / 20 mm to 4.0 N / 20 mm, still more preferably 2.0 N / 20 mm to 3.8 N / 20 mm, particularly preferably 2.0 N / 20 mm to 3.5 N / 20 mm. It is. By adjusting the adhesive force in the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention is an adherend having a rough surface in low-speed peeling when exposed to an environmental load for long-term storage. In contrast, sufficient and moderately high adhesive strength can be expressed. In addition, the measuring method of the various adhesive force with respect to a SUS304 hairline board is mentioned later.

  In addition, what is called a "SUS hairline board" in this specification is a SUS board by which the surface was hairline processed, Comprising: Surface roughness Ra has a rough surface of 0.210 micrometer-0.310 micrometer. This surface roughness Ra was measured in a direction perpendicular to the stripe direction of the hairline in a hairline-processed SUS plate using a contact surface roughness meter (SJ400: manufactured by Mitutoyo Corporation) (measuring condition: JIS-B). -0601: measured in accordance with (2001), specifically, measured at a stylus radius of 2 μm, a cut-off value of 0.8 mm, and a measurement length of 4 mm).

  The surface protective sheet of the present invention has a breaking strength of preferably 20 N / 20 mm or more, more preferably 20 N / 20 mm to 50 N / 20 mm, still more preferably 20 N / 20 mm to 45 N / 20 mm, and particularly preferably. It is 20N / 20mm-40N / 20mm. By adjusting the breaking strength of the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention can exhibit sufficient mechanical strength. A method for measuring the breaking strength will be described later.

  The surface protective sheet of the present invention has an elongation at break of preferably 200% or more, more preferably 200% to 600%, still more preferably 200% to 500%, and particularly preferably 200% to 400%. %. By adjusting the elongation at break in the surface protective sheet of the present invention within the above range, the surface protective sheet of the present invention can exhibit sufficient mechanical strength. A method for measuring elongation at break will be described later.

  The surface protective sheet of the present invention is preferably formed by integrally forming a white base material layer, a black 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.

  The method for producing a surface protective sheet of the present invention is preferably produced by integrally forming a white base material layer, a black base material layer, and an 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 white base material layer and the adhesive layer are not in contact with each other in the melt-heated state. There is no transfer to the layer, excellent rewinding property is 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. In accordance with JIS B0601 (2001), the surface roughness Ra (μm) of the white base layer of the attached surface protective sheet is adjusted to a stylus tip diameter of 2 μm, a measurement length of 4 mm, and a cutoff of 0.8 mm. Measured.

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

(Measurement of initial adhesive strength to SUS430BA board)
The initial adhesion force to a SUS430BA plate at 23 ° C. at 180 ° peel at a tensile speed of 0.3 m / min was measured as follows.
That is, the initial adhesive strength was measured according to JIS-Z-0237 (2000). Specifically, an SUS430BA plate was used as an adherend, the surface of the SUS430BA plate was washed with toluene, a 2 kg roller was reciprocated once, and an evaluation sample was pressure-bonded. After 30 minutes, an Instron type tensile tester The tensile speed was set to the above speed (manufactured by Shimadzu Corporation, Autograph), and the initial adhesive force was measured at 180 ° peel. At this time, the measurement environment and the storage environment were a temperature of 23 ° C./humidity of 50%.

(Measurement of adhesive strength one week after sticking to SUS430BA board)
The adhesive strength after 1 week from the sticking to the SUS430BA plate at 23 ° C. at 180 ° peel at a tensile speed of 0.3 m / min was measured as follows.
That is, the said adhesive force was measured based on JIS-Z-0237 (2000). Specifically, an SUS430BA plate was used as an adherend, the surface of the SUS430BA plate was washed with toluene, a 2 kg roller was reciprocated once, and an evaluation sample was pressure-bonded. Using a machine (manufactured by Shimadzu Corporation, Autograph), the tensile speed was set to the above speed, and the adhesive strength was measured at 180 ° peel. At this time, the measurement environment was a temperature of 23 ° C./humidity of 50%.

(Measurement of initial adhesive strength to SUS304 hairline board)
The initial adhesion force to the SUS304 hairline plate at 23 ° C. at 180 ° peel at a tensile speed of 0.3 m / min was measured as follows.
That is, the initial adhesive strength was measured according to JIS-Z-0237 (2000). Specifically, an SUS304 hairline plate is used as an adherend, the surface of the SUS304 hairline plate is washed with toluene, a 2 kg roller is reciprocated once, and an evaluation sample is pressure-bonded. With a testing machine (manufactured by Shimadzu Corporation, Autograph), the tensile speed was set to the above speed, and the initial adhesive force was measured at 180 ° peel. At this time, the measurement environment and the storage environment were a temperature of 23 ° C./humidity of 50%.

(Measurement of adhesive strength one week after sticking to SUS304 hairline board)
The adhesive force after one week from the sticking to the SUS304 hairline plate at 23 ° C. at 180 ° peel at a tensile speed of 0.3 m / min was measured as follows.
That is, the said adhesive force was measured based on JIS-Z-0237 (2000). Specifically, an SUS304 hairline plate is used as an adherend, the surface of the SUS304 hairline plate is washed with toluene, a 2 kg roller is reciprocated once, and an evaluation sample is pressure-bonded. With a tensile tester (manufactured by Shimadzu Corporation, Autograph), the tensile speed was set to the above speed, and the adhesive strength was measured at 180 ° peel. At this time, the measurement environment was a temperature of 23 ° C./humidity of 50%.

(Measurement of breaking strength)
The breaking strength was measured as follows.
A tensile test was performed according to JIS-K-7127. The measurement sample was a surface protection sheet cut into the shape of the test piece type 2 described in JIS-K-7127, and the measurement was performed at a chuck interval of 50 mm, a test piece width of 10 mm, and a test speed of 300 mm / min. Moreover, the testing machine used for the measurement was an Instron type tensile testing machine (manufactured by Shimadzu Corporation, Autograph). The strength when the sample at the time of the tensile test broke was calculated by N / 20 mm.

(Measurement of elongation at break)
The elongation at break was measured as follows.
A tensile test was performed according to JIS-K-7127. The measurement sample was a surface protection sheet cut into the shape of the test piece type 2 described in JIS-K-7127, and the measurement was performed at a chuck interval of 50 mm, a test piece width of 10 mm, and a test speed of 300 mm / min. Moreover, the testing machine used for the measurement was an Instron type tensile testing machine (manufactured by Shimadzu Corporation, Autograph). The amount of elongation when the sample at the time of the tensile test broke was calculated in% based on the distance between chucks of 50 mm.

(Bending test)
The bending test was measured as follows.
A stainless steel plate (304HL) having a thickness of 2.0 mm is pressure-bonded with a 2 kg roller, and a surface protective sheet is attached. After the surface protective sheet is placed on the opposite side of the punch, a metal V bending process test (V block method) ) (JIS-Z-2248). At this time, the die V angle is 88 degrees, the die V width (L width) is 16 or 12 mm, the die R is 2.0 or 1.0 mm, the punch angle is 88 degrees, and the punch R is 0.6. The case where the surface protective sheet was cut after the bending process was evaluated as x, and the case where the surface protective sheet was not generated was evaluated as ◯. Moreover, the surface protection sheet after a process was peeled and the presence or absence of the damage | wound on a stainless steel plate surface was confirmed. The case where a flaw occurred was marked with ×, and the case where no flaw occurred was marked with ○.

(Foreign matter visibility)
Alumina particles (average particle size = 10 μm, Showa Denko, CB-A10S) were attached to a cotton swab and adhered to the surface of a SUS430BA plate. A surface protection sheet was attached to the SUS430BA plate with the alumina particles adhered to the surface, laminated at 0.4 MPa, and then visually checked for the presence or absence of biting particles. The case where the entrained particles were visible was marked as x, and the case where the particles were not visible was marked as o.

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

[Example 1]
As shown in Table 1, 80 parts by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ) and silica (average particle size = 6.8 μm, Unimin, Minex 4) 2 parts by weight was blended, and further 18 parts by weight of a white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) was blended to obtain a white base material layer forming material.
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (1) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

[Example 2]
As shown in Table 1, 78.5 parts by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle diameter = 6.8 μm, Unimin, Minex) 4) 3.5 parts by weight was blended, and 18 parts by weight of a white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) was blended to obtain a white base layer forming material.
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (2) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 3
As shown in Table 1, 75 parts by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ) and silica (average particle size = 6.8 μm, manufactured by Unimin, Minex 4) 7 parts by weight was further blended, and further 18 parts by weight of a white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) was blended to obtain a white base layer forming material.
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (3) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 4
As shown in Table 1, 80 parts by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle size = 8.7 μm, Unimin, Minex 4F) 2 parts by weight was blended, and further 18 parts by weight of a white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) was blended to obtain a white base material layer forming material.
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (4) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 5
As shown in Table 1, 78.5 parts by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle size = 8.7 μm, manufactured by Unimin, Minex) 4F) 3.5 parts by weight was blended, and further 18 parts by weight of a white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) was blended to obtain a white base layer forming material.
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (5) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 6
As shown in Table 1, 75 parts by weight of low density polyethylene (manufactured by Tosoh, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle size = 8.7 μm, Unimin, Minex 4F) 7 parts by weight was further blended, and further 18 parts by weight of a white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) was blended to obtain a white base layer forming material.
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (6) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 7
As shown in Table 1, 80 parts by weight of low-density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), calcium carbonate (average particle size = 8.0 μm, Bihoku powdering industry ( Co., Ltd., Softon BF300) 2 parts by weight, and further white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) 18 parts by weight were blended to obtain a white base layer forming material. .
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (7) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

Example 8
As shown in Table 1, 78 parts by weight of low-density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), calcium carbonate (average particle size = 8.0 μm, Bihoku Powdered Industries ( Co., Ltd., Softon BF300) 4 parts by weight, and further white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) 18 parts by weight were blended to obtain a white base layer forming material. .
Next, as shown in Table 1, linear low density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., trade name) was added to 89 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ). : Exelen FX FX307, density = 0.890 g / cm ³ ) 10 parts by weight, and carbon black MB (manufactured by Sumika Color, trade name: Black SPEMB-865, carbon content 20%) 5 parts by weight Thus, a black base material layer forming material was obtained.
Furthermore, as shown in Table 1, 82 parts by weight of HSBR (styrene content = 10% by weight, manufactured by JSR, trade name: Dynalon 1321P) and a tackifier (C5 hydrogenated aromatic petroleum resin, manufactured by Idemitsu Kosan Co., Ltd., trade name) : Imabe P140, softening point = 140 ° C.) and 18 parts by weight were blended to obtain an adhesive layer forming material.
Using the white base layer forming material, black base layer forming material, and adhesive layer forming material obtained above, a three-layer structure (white base layer / black base group) is obtained by coextrusion molding using an inflation method. A surface protective sheet (8) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) was obtained.
The results are shown in Table 1.

[Comparative Example 1]
In the preparation of the white base material layer forming material in Example 1, 81 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle diameter = 6. 8 μm, Unimin, Minex 4) 1 part by weight was mixed, and white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) 18 parts by weight was added, and the same procedure as in Example 1 was performed. Surface protective sheet (C1) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) )
The results are shown in Table 2.

[Comparative Example 2]
In the preparation of the white base material layer forming material in Example 1, 80 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle diameter = 3. 5 μm, Unimin, Minex 7) 2 parts by weight were blended, and white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) 18 parts by weight was blended in the same manner as in Example 1, Surface protective sheet (C2) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) )
The results are shown in Table 2.

[Comparative Example 3]
In the preparation of the white base material layer forming material in Example 1, 78.5 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle diameter = Example 1 except that 3.5 μm, Unimin, Minex 7) 3.5 parts by weight and further 18 parts by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) were added. Surface protection sheet (C3) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base layer / adhesive layer = 20 μm) / 35 μm / 5 μm).
The results are shown in Table 2.

[Comparative Example 4]
In the preparation of the white base layer forming material in Example 1, 75 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), silica (average particle diameter = 3. 5 μm, Unimin, Minex 7) 7 parts by weight, further white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) 18 parts by weight, except that the same as Example 1, Surface protective sheet (C4) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base layer / adhesive layer = 20 μm / 35 μm / 5 μm) )
The results are shown in Table 2.

[Comparative Example 5]
In the preparation of the white base material layer-forming material in Example 7, 80 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), calcium carbonate (average particle diameter = 3) .2 μm, 2 parts by weight of Shiroishi Calcium Co., Ltd., PO-150-B-10) are blended, and 18 parts by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) is blended. Was carried out in the same manner as in Example 7, and the surface protective sheet (C5) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base) Layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

[Comparative Example 6]
In the preparation of the white base material layer forming material in Example 7, 75 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), calcium carbonate (average particle diameter = 3) .2 μm, 7 parts by weight of Shiraishi Calcium Co., Ltd., PO-150-B-10) are blended, and 18 parts by weight of white pigment (titanium oxide, manufactured by Dupont, trade name: Ti-Pure R103) is blended. Was carried out in the same manner as in Example 7, and the surface protective sheet (C6) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base) Layer / adhesive layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

[Comparative Example 7]
In the preparation of the white base material layer forming material in Example 7, 80 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), calcium carbonate (average particle diameter = 1) .5 μm, 2 parts by weight of Bihoku Flour Industries Co., Ltd., Softon 1500), and other than 18 parts by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) Surface protection sheet (C7) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base layer / adhesive) Layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

[Comparative Example 8]
In the preparation of the white base material layer forming material in Example 7, 75 parts by weight of low density polyethylene (manufactured by Tosoh Corporation, trade name: Petrocene 186R, density = 0.924 g / cm ³ ), calcium carbonate (average particle diameter = 1) .5 μm, 7 parts by weight of Bihoku Powder Chemical Co., Ltd., Softon 1500), and other than 18 parts by weight of white pigment (titanium oxide, manufactured by DuPont, trade name: Ti-Pure R103) Surface protection sheet (C8) having a three-layer structure (white base layer / black base layer / adhesive layer) (thickness: white base layer / black base layer / adhesive) Layer = 20 μm / 35 μm / 5 μm).
The results are shown in Table 2.

  From Table 1 and Table 2, the surface protective sheet of the present invention has a surface roughness Ra of 0.30 μm or more on the outermost surface of the white base layer, and 60 ° gloss on the outermost surface of the white base layer. The surface glossiness is 65 or less, and the outermost surface of the base material layer is roughened to the extent that foreign matter is not noticeable between the surface protection sheet and the adherend, and the surface is smooth. Even if it is a to-be-adhered body or a rough adherend, it exhibits sufficient and appropriate adhesive strength, excellent mechanical properties such as breaking strength and elongation at break, and excellent bending workability. I understand.

  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 21 White base material layer 22 Black base material layer 30 Inorganic particle

Claims (17)

A surface protective sheet comprising a white base layer, a black base layer and an adhesive layer in this order,
The white base layer is the outermost layer;
The surface roughness Ra of the outermost surface of the white base layer is 0.30 μm or more,
The surface glossiness of 60 ° gloss on the outermost surface of the white base layer is 65 or less,
Surface protection sheet.   The surface protection sheet according to claim 1, wherein inorganic particles are contained in the white base material layer.   The surface protection sheet of Claim 2 whose content rate of the inorganic particle in the said white type | system | group base material layer is 2 weight%-8 weight%.   The surface protection sheet of Claim 2 or 3 whose average particle diameter of the said inorganic particle is 5 micrometers-10 micrometers. The surface protection sheet according to any one of claims 2 to 4, wherein the inorganic particles are at least one selected from SiO ₂ and CaCO ₃ .   The surface protection sheet according to any one of claims 1 to 5, wherein the white base material layer, the black base material layer, and the adhesive layer are integrally formed by coextrusion molding.   The surface protection sheet in any one of Claim 1 to 6 in which the said white-type base material layer contains a polyethylene-type resin as a main component.   The surface protection sheet of Claim 7 in which the said polyethylene-type resin contains a low density polyethylene.   The surface protection sheet in any one of Claim 1-8 in which the said black base material layer contains a polyethylene-type resin as a main component.   The surface protection sheet of Claim 9 in which the said polyethylene-type resin contains a low density polyethylene.   The surface protection sheet of Claim 9 or 10 in which the said polyethylene-type resin contains a linear low density polyethylene.   The surface protective sheet according to any one of claims 1 to 11, wherein an initial adhesive force to the SUS430BA plate at 23 ° C is 1.0 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min.   The adhesive strength one week after sticking to a SUS430BA plate at 23 ° C is 2.0 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min. A surface protective sheet according to 1.   The surface protection sheet according to any one of claims 1 to 13, wherein an initial adhesive force to the SUS304 hairline plate at 23 ° C is 1.5 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min. .   The adhesive strength after one week from the sticking to the SUS304 hairline plate at 23 ° C is 2.0 N / 20 mm or more at 180 ° peel at a tensile speed of 0.3 m / min. The surface protection sheet of crab.   The surface protection sheet in any one of Claim 1-15 whose breaking strength is 20 N / 20mm or more. The surface protection sheet according to any one of claims 1 to 16, which has an elongation at break of 200% or more.

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