Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
  • G02B1/045—Light guides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B25/00—Layered products comprising a layer of natural or synthetic rubber
  • B32B25/04—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B25/08—Layered products comprising a layer of natural or synthetic rubber comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
  • B32B27/302—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/06—Interconnection of layers permitting easy separation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
  • C09J7/24—Plastics; Metallised plastics based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C09J7/241—Polyolefin, e.g.rubber
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/40—Adhesives in the form of films or foils characterised by release liners
  • C09J7/401—Adhesives in the form of films or foils characterised by release liners characterised by the release coating composition
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/02—Diffusing elements; Afocal elements
  • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
  • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
  • G02B5/0231—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having microprismatic or micropyramidal shape
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/04—Prisms
  • G02B5/045—Prism arrays
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/70—Other properties
  • B32B2307/748—Releasability
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2457/00—Electrical equipment
  • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
  • B32B2457/202—LCD, i.e. liquid crystal displays
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2551/00—Optical elements
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils

Definitions

• the present invention relates to a surface protective film for a prism sheet, a manufacturing method thereof, and a prism sheet to which the film is attached.
• the prism sheet has a plurality of triangular prisms serving as lens surfaces on one side, and can improve the brightness of the liquid crystal display.
• a surface protection film is attached to the prism formed on the surface of the prism sheet for protection.
• the adhesive used for the surface protective film is a rubber-based adhesive that has a small increase in adhesive strength due to heating or passage of time. An adhesive is used.
• the surface protection film is handled as a scroll.
• the rubber-based pressure-sensitive adhesive generally has a large force (development force) required for unwinding from the scroll, and there is a problem that the deployment force gradually increases when stored as a scroll for a long period of time.
• a surface protective film with a large unfolding force is drawn out from the roll while the surface protective film is pulled. Therefore, when the surface protective film is affixed to the prism sheet, the surface protective film is lifted from the adhesive surface with the prism sheet. There is a problem that a so-called “float” is generated. For this reason, there has been a demand for a surface protective film having a small development force (so-called “light development”).
• Patent Document 1 proposes a surface protective film in which a release layer is difficult to transfer to an adhesive layer.
• the release layer of the surface protective film described in Patent Document 1 is formed by applying a release agent to the substrate.
• a release agent is applied using an organic solvent, the load on the environment is large. Further, when an aqueous dispersion of a release agent is applied, a drying process is required.
• an ultraviolet curable resin liquid as a release agent is applied, an ultraviolet irradiation device is required.
• An object of the present invention is to provide a surface protection film for a prism sheet that has a small development force from a scroll and is less likely to have a decrease in adhesive force even if a release layer adheres to the adhesive layer.
• Another object of the present invention is to provide a method for producing a surface protective film for a prism sheet of the present invention.
• the present invention provides a surface protective film of the following [1] to [6], a method for producing the surface protective film of the following [7], and a prism sheet on which the surface protective film of the following [8] is attached.
• [1] Molding raw material A containing saturated fatty acid bisamide and polyolefin resin, and molding raw material B containing styrene elastomer Manufactured by co-extrusion, (A) A release layer mainly composed of saturated fatty acid bisamide and having a thickness of 1 to 100 nm; (B) a polyolefin resin layer as a base material layer; and (C) a styrene elastomer layer as an adhesive layer.
• Surface protection film for prism sheets are examples of the following [1] to [6], a method for producing the surface protective film of the following [7], and a prism sheet on which the surface protective film of the following [8] is attached.
• the saturated fatty acid bisamide is ethylene bis stearamide, methylene bis stearamide, or hexamethylene bis stearamide.
• the saturated fatty acid bisamide is a saturated fatty acid aromatic bisamide.
• a prism sheet having a plurality of triangular prisms on the lens surface and (A) a release layer mainly composed of saturated fatty acid bisamide and having a thickness of 1 to 100 nm, (B) Including a surface protective film for a prism sheet in which a polyolefin resin layer as a material layer, and (C) a styrene elastomer layer as an adhesive layer are laminated, A prism sheet having a surface protective film attached thereto, wherein a depth of penetration of the prism into the pressure-sensitive adhesive layer is 0.3 ⁇ m or more.
• a surface protective film for a prism sheet that has a small development force from a scroll and that does not easily lower the adhesive force even when a release layer adheres to the adhesive layer.
• the surface protective film for a prism sheet of the present invention is (A) A release layer mainly composed of saturated fatty acid bisamide and having a thickness of 1 to 100 nm, (B) a polyolefin resin layer as a base material layer, and (C) a styrene elastomer layer as an adhesive layer in this order. Are stacked.
• the thickness of the surface protective film for a prism sheet of the present invention is not particularly limited, but the lower limit is usually 12 ⁇ m, preferably 20 ⁇ m, and the upper limit is usually 100 ⁇ m, preferably 60 ⁇ m, more preferably 50 ⁇ m, still more preferably. 45 ⁇ m.
• the release layer is mainly composed of saturated fatty acid bisamide.
• “consisting mainly of” means that the release layer is formed of saturated fatty acid bisamide bleeded out from the olefin resin layer. More specifically, it means that the content of saturated fatty acid bisamide is 90% by weight or more of the entire release layer.
• Saturated fatty acid bisamides include, for example, saturated fatty acid aliphatic bisamides such as ethylene bis stearamide, methylene bis stearamide, and hexamethylene bis stearamide; and m-xylylene bis stearamide, and NN ′ Saturated fatty acid aromatic bisamides such as distearyl isophthalic acid amide are preferred.
• saturated fatty acid aliphatic bisamides ethylene bis stearamide is more preferable.
• saturated fatty acid aromatic bisamides m-xylylene bisstearic acid amide is more preferable.
• the thickness of the release layer is 1 to 100 nm.
• the lower limit of the thickness is preferably 5 nm, more preferably 7 nm, and still more preferably 9 nm.
• the upper limit of the thickness is preferably 80 nm, more preferably 60 nm, and still more preferably 40 nm.
• the release layer is in contact with the pressure-sensitive adhesive layer and transferred to the surface of the pressure-sensitive adhesive layer. Therefore, if the ridgeline of the prism on the surface of the prism sheet breaks through the release layer and the depth of penetration of the prism into the adhesive is 0.3 ⁇ m or more, there will be no occurrence of floating, which is a practical problem. No adhesive force can be secured.
• the release layer When the release layer has a thickness of 100 nm or less, it adheres to the pressure-sensitive adhesive layer when the surface protection film is rewound from the roll by the ridgeline of the prismatic prism of the prism sheet when the prism sheet is attached ( That is, the transferred release layer is broken through, and the prism sheet and the pressure-sensitive adhesive layer come into contact with each other. Thereby, a practically sufficient adhesive strength can be obtained.
• the thickness of the release layer is 1 nm or more, the deploying force from the scroll can be sufficiently reduced.
• the thickness of the release layer is obtained by the following method.
• the surface protective film for a prism sheet of the present invention is dyed with ruthenium tetroxide, and the release layer and the base material layer are dyed using the difference in ease of dyeing.
• a resin sample in which a surface protective film is sealed is repeatedly thinned using an ultramicrotome (Reicart ULTRACUT S, manufactured by Leica Co., Ltd.) with a section thickness set to 70 nm to create a plurality of thin film pieces.
• An observation thin film piece capable of observing the cross section of the release layer and the base material layer is selected from a plurality of thin film pieces using a transmission electron microscope. The observation thin film piece was observed using a transmission electron microscope, and the thickness of the release layer was measured at three locations. The average value of the measured values is taken as the thickness of the release layer.
• Base material layer A base material layer consists of polyolefin resin.
• the release layer of the surface protective film for a prism sheet of the present invention is formed by bleeding out the release agent from the base material layer.
• the saturated fatty acid bisamide added to the polyolefin-based resin for forming the release layer remains.
• polyolefin resins examples include low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, ethylene- ⁇ -olefin copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-acetic acid.
• examples include vinyl copolymer resins, ethylene-methyl acrylate copolymer resins, ethylene-n-butyl acrylate copolymer resins, and polypropylene resins, and mixtures thereof.
• Such a resin may contain an additive usually added to the resin.
• the additive include an antioxidant, an ultraviolet absorber, and an antiaging agent.
• the amount of the additive is usually 5% by weight or less, preferably 3% by weight or less, based on the entire resin.
• the thickness of the base material layer can be appropriately adjusted according to the material of the prism sheet and the shape of the prism, and is generally set to 4 to 80 ⁇ m, preferably 20 to 50 ⁇ m.
• the pressure-sensitive adhesive layer contains a styrene-based elastomer.
• the pressure-sensitive adhesive layer mainly contains a styrene-based elastomer and preferably further contains a tackifier.
• the main component means that it occupies the most weight among all components of the pressure-sensitive adhesive layer, and preferably means that it is contained by 50% by weight or more.
• the styrene elastomer used in the present invention is preferably the following polymer (i), the following polymer (ii), or a mixture thereof.
• the “polymer (i)” includes the following polymer block A and the following polymer block B, and is represented by the general formula [AB] n (wherein A represents the polymer block A and B represents the polymer block B). , N represents an integer of 1 to 3, and is a copolymer (I) having a structure represented by the formula (I) or a hydrogenated product thereof.
• n represents an integer of 1 to 3
• the structure represented by the formula [AB] n includes, for example, AB, ABAB, And a structure represented by ABABABAB.
• a and B may be the same or different in repetition.
• the “polymer (ii)” includes the following polymer block A and the following polymer block B, and is represented by the general formula ABA (the symbols in the formula are as defined above) or the general formula (A— B) xY (wherein x represents an integer of 2 or more, Y represents a coupling agent residue, and other symbols are as defined above). Or a hydrogenated product thereof.
• the styrenic elastomer is a mixture of the polymer (i) and the polymer (ii), and the total amount and weight of the polymer block A contained in the polymer (i) and the polymer (ii).
• Polymer block A is a polymer block in which aromatic alkenyl compound units are continuous and mainly composed of aromatic alkenyl compound units.
• Polymer block B is an aromatic alkenyl-conjugated diene copolymer block containing conjugated diene compound units and aromatic alkenyl compound units randomly.
• the “aromatic alkenyl compound unit” is a repeating unit derived from an aromatic alkenyl compound.
• aromatic alkenyl compound examples include styrene, tert-butylstyrene, ⁇ -methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1-diphenylethylene, vinylnaphthalene, vinylanthracene, N , N-diethyl-p-aminoethylstyrene, vinylpyridine and the like.
• conjugated diene compound examples include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-octadiene, 1,3- Examples include hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, myrcene, and chloroprene.
• the thickness of the pressure-sensitive adhesive layer is not particularly limited, but is 2 to 20 ⁇ m, preferably 3 to 15 ⁇ m.
• the pressure-sensitive adhesive layer of the present invention usually contains a tackifier.
• the tackifier examples include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymers and alicyclic copolymers, and coumarone-indene resins. , Terpene resins, terpene phenol resins, polymerized rosin resins such as rosin, (alkyl) phenol resins, xylene resins or hydrogenated products such as those generally used for pressure-sensitive adhesives are used without particular limitation can do. It is more preferable to use a tackifier having a softening point of 90 to 140 ° C. These tackifiers may be used alone or in combination of two or more. In addition, in order to improve peelability and weather resistance, it is more preferable to use a hydrogenated resin as a tackifier. Moreover, you may use the tackifier marketed as a mixture with an olefin resin.
• the tackifier is preferably compatible with the polymer block B having a conjugated diene compound unit or a hydrogenated conjugated diene compound unit.
• the tackifier is used in an amount that can prevent adhesive residue when the surface protective film is peeled off from the adherend.
• the blending ratio of the tackifier is preferably 5 to 50 parts by weight, more preferably 20 to 40 parts by weight with respect to 100 parts by weight of the styrene elastomer.
• the blending ratio varies depending on the type of tackifier. For example, in the case of a tackifier having a softening point of 90 to 140 ° C., it is preferably 15 to 40 weights, more preferably 20 to 20 weights per 100 parts by weight of the styrene elastomer. 30 parts by weight. If the amount of the tackifier is within this range, even if the surface protective film is applied to the prism sheet for a long time, the adhesive force is not easily lowered, and the surface protective film bonded to the prism sheet is difficult to lift.
• known additives such as a softening agent, an antioxidant, and an adhesion progressing preventing agent can be blended as necessary for the purpose of controlling the adhesive strength.
• softener examples include low molecular weight diene polymer, polyisobutylene hydrogenated polyisoprene, hydrogenated polybutadiene, paraffin process oil, naphthene process oil, aromatic process oil, castor oil, tall oil, natural oil, liquid Examples thereof include polyisobutylene resin, polybutene, and hydrogenated products thereof. These softeners may be used alone or in combination of two or more.
• the antioxidant is not particularly limited.
• a phenol-based antioxidant eg, monophenol-based antioxidant, bisphenol-based antioxidant, polymer-type phenol-based antioxidant
• sulfur-based antioxidant examples thereof include phosphorus antioxidants.
• Adhesion progress inhibitors include fatty acid amides, polyethyleneimine long-chain alkyl grafts, soybean oil-modified alkyd resin (Arakawa Chemical Co., trade name “Arachid 251”), tall oil-modified alkyd resin (Arakawa Chemical Co., Ltd., product) Name "Arachid 6300").
• Adhesion progress inhibitors include fatty acid amides, polyethyleneimine long-chain alkyl grafts, soybean oil-modified alkyd resin (Arakawa Chemical Co., trade name “Arachid 251”), tall oil-modified alkyd resin (Arakawa Chemical Co., Ltd., product) Name "Arachid 6300").
• the surface protective film for a prism sheet of the present invention may further include an intermediate layer between the base material layer and the pressure-sensitive adhesive layer.
• the release layer is formed by bleeding out to the surface in the process where the surface of the base material layer (opposite side of the adhesive layer) melted immediately after coextrusion comes into contact with the cooling roll and solidifies. At this time, saturated fatty acid bisamide bleeds out also on the surface of the base material layer opposite to the release layer. When the saturated fatty acid bisamide layer is in contact with the pressure-sensitive adhesive layer, the bonding force between the base material layer and the pressure-sensitive adhesive layer may be reduced.
• the intermediate layer has a function of preventing a decrease in the bonding force.
• the intermediate layer may be a resin that can be bonded to the base material layer and the adhesive layer, but a layer made of a polyolefin resin is preferable.
• the polyolefin resin in the intermediate layer contains a saturated fatty acid bisamide and a styrene elastomer.
• Such an intermediate layer may be manufactured using the end material of the surface protective film for prism sheet.
• the surface protective film for a prism sheet of the present invention is produced by co-extrusion of a molding raw material A made of a polyolefin resin containing a saturated fatty acid bisamide and a molding raw material B containing a styrene elastomer.
• the saturated fatty acid bisamide is usually synthesized by a dehydration condensation reaction between a diamine and a saturated fatty acid. For this reason, saturated fatty acid bisamide may contain diamine and saturated fatty acid as impurities.
• the diamine and saturated fatty acid described above are related to the characteristics of the method for producing a surface protective film for a prism sheet according to the present invention in which a release layer is formed by bleed out. It was found that the production apparatus was contaminated during the production of the prism sheet surface protective film. Therefore, the saturated fatty acid bisamide used in the present invention preferably has a low content of diamine and saturated fatty acid.
• Molding raw material A and molding raw material B can be prepared by mixing each component by a known method.
• the molding raw material A specifically, it can be prepared by pelletizing a polyolefin-based resin containing a saturated fatty acid amide with a twin screw extruder.
• the thickness of the release layer formed on the surface of the base material layer can be adjusted.
• the lower limit of the amount of the saturated fatty acid bisamide contained in the molding raw material A is preferably 1 part by weight, more preferably 1.5 parts by weight with respect to 100 parts by weight of the polyolefin-based resin in order to form a release layer by bleeding out. Part.
• the upper limit of the amount of saturated fatty acid bisamide contained in the molding raw material A is to obtain sufficient adhesive strength with the prism sheet by forming a release layer having an appropriate thickness, and the peeled release layer is formed on the molding roll. From the viewpoint of suppressing adhesion, the amount is preferably 4 parts by weight, more preferably 2 to 3 parts by weight with respect to 100 parts by weight of the polyolefin resin.
• a molding raw material A made of a polyolefin resin containing saturated fatty acid bisamide and a molding raw material B containing a styrene elastomer are coextruded by, for example, a T-die method using two or more multilayer extruders. Thereafter, the resin side from which the forming raw material A is extruded is rapidly cooled with a cooling roll. Thereby, a multilayer film is obtained.
• the extrusion temperature is preferably 160 to 230 ° C.
• a base material layer and an adhesive layer are formed by coextrusion.
• the base layer immediately after co-extrusion comes into contact with the cooling roll, and the saturated fatty acid bisamide contained in the forming raw material A bleeds out to the surface of the base layer due to its own properties, thereby forming a release layer. Is done.
• a release layer of 1 to 100 nm is formed on the surface of the base material layer.
• the surface protective film of the present invention thus formed is usually cooled by a cast roll, wound by a take-up roll, and stored as a roll.
• the cast roll temperature is set to 20 to 90 ° C.
• the release layer of the present invention is a layer formed on the surface of the base material layer opposite to the pressure-sensitive adhesive layer.
• the surface protective film for a prism sheet of the present invention is usually wound up and stored as a scroll.
• the release layer contacts the pressure-sensitive adhesive surface of the wound pressure-sensitive adhesive layer.
• a part of the release layer is transferred to the surface of the adhesive surface.
• the adhesive force of the surface protective film is significantly reduced by the transfer of the release layer.
• the ridge line of the prism of the prism sheet breaks through the transferred release layer. Thereby, even if the release layer is transferred, the adhesive force of the adhesive layer is exhibited.
• the prism biting depth of the prism sheet into the pressure-sensitive adhesive layer is preferably 0.3 ⁇ m or more. Thereby, an appropriate adhesive strength is exhibited.
• the upper limit of the bite depth is not particularly limited, but is usually 2 ⁇ m or less.
• the biting depth was affixed at a speed of 300 mm / min using a 2 kg pressure rubber roller in an environment of a room temperature of 23 ° C. and a relative humidity of 50%, and left in that state for 30 minutes, and then a surface protective film was applied. This is a numerical value measured by freezing the prism sheet using a freezing microtome and observing the cut section using a scanning electron microscope.
• the bite depth is adjusted by adjusting the shear modulus and thickness of the pressure-sensitive adhesive layer of the surface protective film of the present invention according to the size of the prism ridge of the prism of the prism sheet to which the surface protective film of the present invention is applied. Can be adjusted.
• the shear modulus (23 ° C.) of the pressure-sensitive adhesive layer is preferably 5 ⁇ 10 6 or less.
• the shear elastic modulus is preferably 5 ⁇ 10 4 or more.
• the thickness of the pressure-sensitive adhesive layer is preferably 4 ⁇ m or more. However, from the viewpoint of cost, the thickness is preferably 15 ⁇ m or less.
• the roll of the surface protective film of the present invention can be easily rewound.
• the deploying force at a speed of 20 m / min with a 50 mm width scroll is preferably 3.5 N or less, more preferably 2 N or less.
• the surface protective film of the present invention preferably has a pasting adhesive strength at 23 ° C. measured under the following conditions of 0.05 to 0.50 N / 25 mm. [conditions] Within 3 days from the creation of the surface protective film, a 25 mm wide surface protective film is applied so as to cover the lens surface of the prism sheet. A prism sheet made of acrylic resin having a thickness of 130 ⁇ m and having a prism pitch of 50 ⁇ m and a height of 25 ⁇ m is used. A surface protective film is attached at a speed of 300 mm / min using a 2 kg pressure-bonded rubber roller in an environment of room temperature 23 ° C. and relative humidity 50%. After being left for 2 weeks in an environment of room temperature 23 ° C.
• the surface protective film is peeled off at a speed of 300 mm / min in accordance with JIS Z0237, and the 180 ° peel strength is measured.
• the direction in which the surface protective film is peeled off is the ridge line direction of the prism.
• the 180 degree peel strength measured in this way is defined as the adhesive strength with time at 23 ° C.
• the surface protective film for a prism sheet of the present invention is attached to the lens surface of the prism sheet.
• Prism sheet with a surface protective film to which the surface protective film for a prism sheet of the present invention is attached A prism sheet having a plurality of triangular prisms on the lens surface, and (A) a release layer mainly composed of saturated fatty acid bisamide and having a thickness of 1 to 100 nm, (B) Including a surface protective film for a prism sheet in which a polyolefin resin layer as a material layer, and (C) a styrene elastomer layer as an adhesive layer are laminated,
• a prism sheet to which the surface protective film for a prism sheet of the present invention is attached for example, in a plurality of triangular prisms having apex angles of about 90 ° on the ridge line on the lens surface, between the vertices of adjacent prisms.
• the distance is about 10 to 1000 ⁇ m.
• a prism sheet to which such a surface protective film is attached A prism sheet having a plurality of triangular prisms on a lens surface, and the prism sheet according to any one of [1] to [6] attached to a lens surface of the prism sheet; A prism sheet on which a surface protective film is attached, in which a depth of biting of the prism into the pressure-sensitive adhesive layer is 0.3 ⁇ m or more, is preferable.
• Example 1 As a forming raw material A, a mixture of 100 parts by weight of polypropylene “Y900GV (manufactured by Prime Polymer)” and 1 part by weight of ethylene bis-stearic acid amide “Alflow H50F (manufactured by NOF Corporation)” which is a saturated fatty acid bisamide, and a forming raw material B As a styrene elastomer “Dynalon 1320P (manufactured by JSR)” 100 parts by weight, tackifier “Alcon P100 (manufactured by Arakawa Chemical)” 20 parts by weight, and antioxidant “Irganox 1010 (manufactured by Ciba Specialty Chemicals)” The mixture consisting of 1 part by weight was coextruded by the T-die method under the following conditions to prepare a surface protective film.
• Y900GV polypropylene
• Alflow H50F manufactured by NOF Corporation
• the surface protective film had a substrate layer thickness of 34 ⁇ m and an adhesive layer thickness of 6 ⁇ m.
• the thickness of the release layer of the surface protective film was 6 nm.
• Method for measuring thickness of release layer> The thickness of the release layer was determined by the following method.
• the prism sheet surface protective film was dyed with ruthenium tetroxide, and the release layer and the base material layer were dyed separately using the difference in ease of dyeing.
• a plurality of thin film pieces were prepared by repeatedly thinning a resin sample in which a surface protective film was encapsulated using an ultramicrotome (REICART ULTRACUT S, manufactured by Leica Co., Ltd.) having a section thickness set to 70 nm.
• An observation thin film piece capable of observing the cross section of the release layer and the base material layer was selected from a plurality of thin film pieces using a transmission electron microscope (JEM-2100, manufactured by JEOL). Observation thin film pieces were observed using a transmission electron microscope (JEOL, JEM-2100), and the thickness of the release layer was measured at three locations. The average value of the measured values was taken as the thickness of the release layer.
• Example 2 A surface protective film was prepared in the same manner as in Example 1 except that the amount of ethylenebisstearic acid amide was 1.5 parts by weight.
• the surface protective film had a substrate layer thickness of 34 ⁇ m, an adhesive layer thickness of 6 ⁇ m, and a release layer thickness of 9 nm.
• Example 3 A surface protective film was prepared in the same manner as in Example 1 except that the amount of ethylenebisstearic acid amide was 3 parts by weight.
• the surface protective film had a substrate layer thickness of 34 ⁇ m and an adhesive layer thickness of 6 ⁇ m. Moreover, the thickness of the release layer of the surface protective film was 80 nm.
• Example 4 The end material produced when both ends of the surface protective film of the present invention were trimmed was molded into pellets using a twin screw extruder.
• a forming raw material A a mixture composed of 100 parts by weight of polypropylene “Y900GV (manufactured by Prime Polymer)” and 1 part by weight of ethylene bis-stearic acid amide “Alflow H50F (manufactured by NOF Corporation)” which is a saturated fatty acid bisamide, and an intermediate layer
• the surface protective film had a base material layer thickness of 28 ⁇ m, an intermediate layer thickness of 6 ⁇ m, and an adhesive layer thickness of 6 ⁇ m. Moreover, the thickness of the release layer of the surface protective film was 65 nm.
• Example 5 A surface protective film was prepared in the same manner as in Example 1 except that 3 parts by weight of methylene bis stearamide “Bisamide LA (manufactured by Nippon Kasei Co., Ltd.)” was used as the saturated fatty acid bisamide.
• the surface protective film had a substrate layer thickness of 34 ⁇ m and an adhesive layer thickness of 6 ⁇ m. Moreover, the thickness of the release layer of the surface protective film was 40 nm.
• Example 6 A surface protective film was prepared in the same manner as in Example 1 except that 2.5 parts by weight of hexamethylene bis-stearic acid “Sripacs ZHS (manufactured by Nippon Kasei Co., Ltd.)” was used as the saturated fatty acid bisamide.
• the surface protective film had a substrate layer thickness of 34 ⁇ m and an adhesive layer thickness of 6 ⁇ m. Moreover, the thickness of the release layer of the surface protective film was 15 nm.
• Example 7 A surface protective film was prepared in the same manner as in Example 1 except that 2.5 parts by weight of m-xylylene bis stearamide “Sripacs PXS (Nihon Kasei Co., Ltd.)” was used as the saturated fatty acid bisamide.
• the surface protective film had a substrate layer thickness of 34 ⁇ m and an adhesive layer thickness of 6 ⁇ m. Moreover, the thickness of the release layer of the surface protective film was 30 nm.
• Comparative Example 1 A surface protective film was obtained in the same manner as in Example 1 except that the saturated fatty acid bisamide was not used.
• Example 2 A surface protective film was prepared in the same manner as in Example 1 except that the amount of ethylenebisstearic acid amide was changed to 0.5 parts by weight. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.
• Example 3 A surface protective film was prepared in the same manner as in Example 1 except that the amount of ethylenebisstearic acid amide was changed to 5 parts by weight. The thickness of the release layer of the surface protective film was 200 nm.
• Example 4 A surface protective film was prepared in the same manner as in Example 1 except that 3 parts by weight of stearic acid amide “Alflow S-10 (manufactured by NOF Corporation)” was used as the saturated fatty acid amide. A surface protective film was prepared. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.
• Example 5 Similar to Example 1 except that 3 parts by weight of oleic acid amide “Alflow E-10 (manufactured by NOF Corporation)” which is an unsaturated fatty acid amide was used instead of ethylene bisstearic acid amide which is a saturated fatty acid bisamide.
• the surface protection film was created by the method. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.
• Example 6 The same procedure as in Example 1 except that 3 parts by weight of erucic acid amide “Alflow P-10 (manufactured by NOF Corporation)” which is an unsaturated fatty acid amide was used instead of ethylene bisstearic acid amide which is a saturated fatty acid bisamide.
• the surface protection film was created by the method. A surface protective film was prepared. An attempt was made to measure the thickness of the release layer, but the release agent layer could not be observed.
• Example 7 Example 1 except that 3 parts by weight of ethylene bisoleic acid amide “Alflow AD-281 (manufactured by NOF Corporation)”, an unsaturated fatty acid bisamide, was used instead of ethylene bisstearic acid amide, which is a saturated fatty acid bisamide.
• a surface protective film was prepared in the same manner. The thickness of the release layer of the surface protective film was 20 nm.
• Each surface protective film was wound around a paper core having an inner diameter of 3 inches to create a 50 mm wide scroll. Based on JIS Z0237, the surface protection film was rewound from the roll at a rewinding speed of 20 m / min, and the high-speed rewinding force was measured. The obtained measured value is the deployment force. Excellent when the deployment force is 2 N / 50 mm or less ((), better than 2 N / 50 mm, good when it is 3.5 N / 50 mm or less ( ⁇ ), poor when the deployment force exceeds 3.5 N / 50 mm ( X).
• the prism is made of an acrylic resin with a thickness of 130 ⁇ m, and the prism pitch is 50 ⁇ m and the height is 25 ⁇ m.
• a test piece was prepared by attaching a surface protective film having a width of 25 mm so as to cover the lens surface of the sheet. The surface protective film was attached to the prism sheet at a rate of 300 mm / min using a 2 kg pressure-bonded rubber roller at a room temperature of 23 ° C. and a relative humidity of 50%. After leaving the test piece in that state for 30 minutes, the presence or absence of floating was evaluated. Those in which no floating occurred were evaluated as good ( ⁇ ), and those in which floating occurred were evaluated as poor ( ⁇ ).
• the initial adhesive force of the test piece in which no lifting occurred was measured.
• the surface protective film was peeled off at a speed of 300 mm / min, and the 180-degree peel strength was measured.
• the direction in which the surface protective film was peeled was the ridge line direction of the prism.
• the obtained 180 degree peel strength is the initial adhesive strength.
• the depth of penetration into the adhesive was 0.6 ⁇ m.
• a surface protective film having a width of 25 mm was attached so as to cover the lens surface of the prism sheet.
• a prism sheet made of acrylic resin having a thickness of 130 ⁇ m and a prism pitch of 50 ⁇ m and a height of 25 ⁇ m was used.
• a surface protective film was attached at a speed of 300 mm / min using a 2 kg pressure-bonded rubber roller in an environment of room temperature of 23 ° C. and relative humidity of 50%. After being left for 2 weeks in an environment of room temperature 23 ° C. and relative humidity 50%, the surface protective film was peeled off at a speed of 300 mm / min in accordance with JIS Z0237, and the 180 ° peel strength was measured.
• the direction in which the surface protective film was peeled was the ridge line direction of the prism.
• the 180 degree peel strength measured in this way was defined as the adhesive strength with time at 23 ° C.
• Example 8 As a forming raw material A, a mixture of 100 parts by weight of polypropylene “Y900GV (manufactured by Prime Polymer)” and 3 parts by weight of ethylene bis stearic acid amide “Alflow H50F (manufactured by NOF Corporation)” which is a saturated fatty acid bisamide, and a forming raw material B As 100 parts by weight of a styrene elastomer “Dynalon 1320P (manufactured by JSR)”, 15 parts by weight of a tackifier “Alcon P100 (manufactured by Arakawa Chemical)” as a tackifier, and “Irganox 1010 as an antioxidant” (Ciba Specialty Chemicals Co., Ltd.) "A mixture consisting of 1 part by weight was coextruded by the T-die method under the following conditions to produce a surface protective film.
• Y900GV manufactured by Prime Polymer
• Alflow H50F manufactured by
• the surface protective film had a thickness of 40 ⁇ m, a base material layer thickness of 34 ⁇ m, and an adhesive layer thickness of 6 ⁇ m. Moreover, the thickness of the release layer of the surface protective film was 49 nm. ⁇ Conditions> Extrusion temperature: 200 ° C Cast roll temperature: 25 ° C
• Example 9 A surface protective film was obtained in the same manner as in Example 8, except that the amount of the tackifier “Arakawa Chemical Co., Ltd.)” was 20 parts by weight. Moreover, the thickness of the release layer of the surface protective film was 50 nm.
• Example 10 A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier “Arakawa Chemical Co., Ltd.)” was 25 parts by weight. Moreover, the thickness of the release layer of the surface protective film was 48 nm.
• Example 11 A surface protective film was obtained in the same manner as in Example 8, except that the amount of the tackifier “Alcon P100 (manufactured by Arakawa Chemical Co.)” was 30 parts by weight. Moreover, the thickness of the release layer of the surface protective film was 53 nm.
• Example 12 A surface protective film was obtained in the same manner as in Example 8, except that the amount of the tackifier “Alcon P100 (manufactured by Arakawa Chemical Co.)” was 35 parts by weight. Moreover, the thickness of the release layer of the surface protective film was 55 nm.
• Example 13 A surface protective film was obtained in the same manner as in Example 8 except that the amount of the tackifier “Arakawa Chemical Co., Ltd.)” was 40 parts by weight. Moreover, the thickness of the release layer of the surface protective film was 48 nm.
• Example 14 A surface protective film was obtained in the same manner as in Example 8, except that the amount of the tackifier “Arakawa Chemical Co., Ltd.)” was 45 parts by weight. Moreover, the thickness of the release layer of the surface protective film was 52 nm.
• Example 8 A surface protective film was obtained in the same manner as in Example 8 except that no saturated fatty acid bisamide was used.
• Comparative Example 9 A surface protective film was obtained in the same manner as in Example 8 except that the saturated fatty acid bisamide was not used and the tackifier “Alcon P100 (Arakawa Chemical Co., Ltd.)” was changed to 30 parts by weight.
• Each surface protective film was wound around a paper core having an inner diameter of 3 inches to prepare a 50 mm wide scroll. Based on JIS Z0237, the surface protection film was rewound from the roll at a rewinding speed of 20 m / min, and the high-speed rewinding force was measured. The measured value obtained is the deployment force. Excellent when the deployment force is 2 N / 50 mm or less ( ⁇ ), better than 2 N / 50 mm, good when it is 3.5 N / 50 mm or less ( ⁇ ), poor when the deployment force exceeds 3.5 N / 50 mm ( X).
• Adhesive strength at 23 ° C pasting time Adhesive strength measured by the same method as the initial adhesive strength except that the surface protective film was left to stand for 1 week in a 23 ° C environment was defined as 23 ° C pasting adhesive strength at 23 ° C. [result]
• the surface protective film not using the saturated fatty acid bisamide has an appropriate adhesive force, but is inferior in the developing force in spite of the amount of the tackifier being suppressed.
• the surface protective film of the present invention using ethylene bis stearic acid amide which is a saturated fatty acid bisamide can obtain an appropriate developing force and an appropriate initial adhesive force.
• Example 15 As a forming raw material A, a mixture of 100 parts by weight of polypropylene “Y900GV (manufactured by Prime Polymer)” and 3 parts by weight of ethylene bis stearic acid amide “Alflow H50F (manufactured by NOF Corporation)” which is a saturated fatty acid bisamide, and a forming raw material B As 100 parts by weight of a styrene elastomer “Dynalon 1320P (manufactured by JSR)”, 20 parts by weight of a tackifier “Alcon P100 (manufactured by Arakawa Chemical)” as a tackifier, and “Irganox 1010 as an antioxidant” (Ciba Specialty Chemicals Co., Ltd.) "A mixture of 1 part by weight was coextruded by the T-die method under the following conditions to prepare a surface protective film.
• the surface protective film had a thickness of 40 ⁇ m, a base material layer
• Adhesive strength room temperature
• a surface protection film roll was prepared and then cured for one week in a constant temperature layer at 23 ° C., and then adhered to the lens surface of the prism sheet and the acrylic plate.
• Pasting conditions were as follows: JIS Z0237 was a product that was pasted at a speed of 300 mm / min using a 2 kg pressure rubber roller in an environment of room temperature 23 ° C. and relative humidity 50%, and then left in a 23 ° C. environment for 1 day.
• the 180 degree peel strength at 25 mm width was measured at a speed of 300 mm / min.
• the measured adhesive force was made into lens surface adhesive force (normal temperature) and flat surface adhesive force (normal temperature), respectively.
• Adhesive strength (40 ° C) The adhesive strength measured by the same method as the adhesive strength (room temperature) except that the curing condition of the roll of the surface protective film was 40 ° C., respectively, the lens surface adhesive strength (40 ° C.) and the flat surface adhesive strength (40 ° C.). It was.
• the surface protective film not using saturated fatty acid bisamide is excellent in adhesive temperature stability but inferior in developing ability.
• the surface protective film of the present invention using ethylene bis-stearic acid amide which is a saturated fatty acid bisamide, when applied to the lens surface of the prism sheet, has both the temperature stability of the adhesive force and the development force. Also excellent.
• the surface protective film of the present invention can be used for protecting the lens surface of the prism sheet.

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