JP2007260983A - Optical sheet and method for producing adhesive layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sheet having an adhesive layer excellent in adhesive properties and a method for producing the adhesive layer. <P>SOLUTION: A prism sheet 30 includes an adhesive layer 34 which is disposed between a prism layer 32 and a substrate 36 and bonds the prism layer 32 and the substrate 36 together. The adhesive layer 34 contains a styrene-butadiene copolymer and a dichloro-s-trialine derivative and is formed through a step of drying at 130°C or above. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical sheet such as a prism sheet, and a method for manufacturing an adhesive layer that bonds a plurality of layers.

  In recent years, an optical lens sheet such as a prism sheet is used to make the display of an electronic display such as a liquid crystal clear, and the brightness of the display is adjusted. As a method of manufacturing such a lens sheet, a method of manufacturing a lens sheet by applying an optical member such as a photocurable resin on a support is known. In this case, since the optical characteristics of the lens sheet change depending on the application accuracy of the optical member on the support, it is important that the optical member is appropriately applied on the support. Under such circumstances, several techniques for appropriately coating the optical member on the support have been proposed.

  For example, Patent Document 1 proposes a method for manufacturing a lenticular lens. In this production method, a primer containing an acrylic polymer is applied to at least one surface of a base material, so that a lenticular lens excellent in adhesiveness to the base material can be obtained with a primer having excellent adhesion.

  Patent Document 2 proposes a method for manufacturing a sheet having a fine uneven shape. In this manufacturing method, the first curable resin and the second curable resin are laminated to form a radiation curable resin, and the reaction cured product of the first curable resin is the second curable resin. It has higher releasability with respect to a roll-shaped mold than a reaction-cured product.

  By the way, a polyester resin film, especially a polyethylene terephthalate biaxially stretched film is excellent in mechanical properties, flame resistance, chemical resistance, etc., so it has been widely used in recent years for magnetic tape, photographic film, packaging film, OHP film, etc. It has been used as a base material for anti-reflection films for OCR equipment, etc., and its demand has been increasing significantly in recent years. In these applications, the film is required to have a desired adhesion. For example, packaging film is adhesive to printing ink and laminate, photographic film is adhesive to photosensitive layer formed on base film, magnetic tape is magnetic recording layer, OCR equipment It is desired that the UV-preventing film has good adhesion to the UV-absorbing paint. However, the polyester film has high surface cohesion due to its crystal orientation and has poor adhesion to various materials.

  Corona treatment, plasma treatment, flame treatment, and the like are known as methods for improving the surface properties of the polyester film, and these treatments are generally used. However, in these treatments, the adhesiveness is improved by physically changing the shape of the film surface, so the performance and transparency of the polyester film may be deteriorated over time.

  In view of such circumstances, a method of providing an easy-adhesion layer by applying a coating on a film has been proposed. As the easy adhesion layer disposed between the film and the laminated member, organic solvent-based and water-based layers are often used. In particular, considering the influence of volatilization and scattering of the easy adhesion layer on the environment, the water-based easy adhesion layer is preferable from the viewpoints of safety, hygiene, and resource saving.

  Therefore, it has been proposed to form the easy-adhesion layer with an aqueous coating agent, and for example, it has been proposed to use a water-soluble or water-dispersible polyester resin. However, depending on the physical properties of the easy-adhesion layer, the adhesion between the polyester film and the easy-adhesion layer can be improved, but the affinity between the laminated material such as coating agents, adhesives, and inks and the easy-adhesion layer is reduced. I might let you. Moreover, if the adhesion between the laminated member and the easy-adhesion layer is improved, the adhesion between the polyester film and the easy-adhesion layer may be reduced, and an easy-adhesion layer having sufficient adhesiveness is selected as the intermediate layer. It is difficult. Furthermore, depending on changes in temperature and humidity during storage, the films may be blocked, and uniform application of surface agents such as diazo paints and UV inks may be difficult.

In view of such circumstances, for example, Patent Document 3 proposes a polyester film having an easy adhesion layer formed by crosslinking an acrylic resin and an acrylic-modified polyester resin. Patent Document 4 proposes a polyester film having a layer containing a styrene-butadiene resin or acrylonitrile-butadiene resin and a specific polyester resin.
JP 2002-365405 A JP 2004-249655 A JP-A-1-108037 Japanese Patent Publication No. 3-22899

  In the prism sheet using the easy-adhesion film produced by the method as described above as a support, the adhesive force between the prism layer formed of the UV curable resin and the support tends to be insufficient.

  The “adhesive strength between the prism layer and the support” as used herein means that the support and the prism layer are separated when the prism layer is peeled off from the mold at the time of manufacture so that the UV curable resin does not remain on the mold side. Adhesive strength, adhesive strength to prevent UV curable resin from falling off the support during prism sheet cutout processing, or adhesive strength to maintain adhesiveness even under conditions used for liquid crystal panel materials , Etc.

  This invention is made | formed in view of the above-mentioned situation, The objective is to provide the optical sheet which has an adhesive layer with the outstanding adhesiveness, and the manufacturing method of such an adhesive layer.

  In order to solve the above-described problems, an optical sheet according to an aspect of the present invention includes an adhesive layer that is provided between a first layer and a second layer and bonds the first layer and the second layer. In the optical sheet, the adhesive layer contains a styrene-butadiene copolymer and a dichloro-s-trialine derivative, and is formed by drying at a temperature of 130 ° C. or higher.

  According to this aspect, an optical sheet including an excellent adhesive layer is provided. The adhesive layer is preferably dried at a temperature of 130 ° C. to 200 ° C., more preferably 150 ° C. to 190 ° C.

  The term “optical sheet” as used herein includes all sheets having an optical function. For example, a sheet in which fine concavo-convex patterns are two-dimensionally arranged, such as a lenticular lens or a prism sheet, or a fly-eye lens. Various embossed sheets such as a sheet in which fine concavo-convex patterns are three-dimensionally arranged, a sheet in which fine cones such as a cone and a pyramid are arranged in the XY direction, such as a flat lens, can also be an object of the present invention.

  Another embodiment of the present invention is also an optical sheet. This optical sheet is an optical sheet that is provided between the first layer and the second layer, and includes an adhesive layer that adheres the first layer and the second layer. It contains a resin and an epoxy crosslinking agent having an average epoxy functional group number of 3.5 or more, and is formed by drying at a temperature of 150 ° C. or more.

  Also in this aspect, an optical sheet provided with an excellent adhesive layer is provided. The adhesive layer is preferably dried at a temperature of 150 ° C. or higher, and more preferably dried at a temperature of 150 ° C. to 190 ° C. in consideration of transportability.

  Yet another embodiment of the present invention is also an optical sheet. This optical sheet is an optical sheet that is provided between the first layer and the second layer, and includes an adhesive layer that adheres the first layer and the second layer. It contains a resin and a carbodiimide-based crosslinking agent and is formed by drying at a temperature of 120 ° C. or higher.

  Also in this aspect, an optical sheet provided with an excellent adhesive layer is provided. The adhesive layer is preferably dried at a temperature of 120 ° C. or higher, and more preferably 120 ° C. to 190 ° C. A carbodiimide-based crosslinking agent is more suitable for low-temperature conditions than an epoxy-based crosslinking agent because it exhibits excellent reactivity even in a low-temperature drying environment.

  The adhesive layer may be a single layer. In this case, the adhesive layer can have a simple configuration.

  The first layer may be a polyester film. In the case where the polyester film is used as the first layer, the present invention can effectively exhibit the effect.

  The adhesive layer may be provided on the first layer that has been subjected to at least one of corona treatment, plasma treatment, glow discharge treatment, and ultraviolet treatment. In this case, the first layer and the adhesive layer are bonded in a better state.

  The second layer may be a prism layer. The present invention can effectively exert its effect on an optical sheet including a prism layer.

  Yet another embodiment of the present invention is a method for producing an adhesive layer. This method is a method for producing an adhesive layer that is provided between a first layer and a second layer and adheres the first layer and the second layer, and includes a styrene-butadiene copolymer and dichloromethane. a step of preparing an adhesive layer solution containing a -s-trialin derivative, and a step of drying the adhesive layer solution at a temperature of 150 ° C. or higher.

  According to this aspect, an adhesive layer having excellent adhesiveness can be produced. The adhesive layer solution is preferably dried at a temperature of 150 ° C. or higher, and more preferably dried at a temperature of 150 ° C. to 190 ° C.

  Yet another embodiment of the present invention is also a method for producing an adhesive layer. This method is a method for producing an adhesive layer that is provided between a first layer and a second layer and adheres the first layer and the second layer, and includes an aqueous urethane resin and an average number of epoxy functional groups. A step of preparing an adhesive layer solution containing an epoxy crosslinking agent of 3.5 or more and a step of drying the adhesive layer solution at a temperature of 150 ° C. or higher.

  Also in this aspect, an adhesive layer having excellent adhesiveness can be produced. In addition, 3.5 or more are preferable and, as for the average number of epoxy functional groups of an epoxy crosslinking agent, 3.5-6.5 are more preferable. Moreover, it is preferable that the solution for contact bonding layers is dried at the temperature of 150 degreeC or more, and it is more preferable that it is dried at 150 to 190 degreeC.

  Yet another embodiment of the present invention is also a method for producing an adhesive layer. This method is a method for producing an adhesive layer that is provided between a first layer and a second layer and adheres the first layer and the second layer, and includes a water-based urethane resin and a carbodiimide-based crosslinking agent. And a step of preparing a solution for an adhesive layer containing, and a step of drying the solution for an adhesive layer at a temperature of 120 ° C. or higher.

  Also in this aspect, an adhesive layer having excellent adhesiveness can be produced. The adhesive layer solution is preferably dried at a temperature of 120 ° C. or higher, and more preferably dried at a temperature of 120 ° C. to 190 ° C.

  In addition, as illustrated in the following embodiments, examples, and the like of the present invention, the above-described actions and effects of the present invention have been confirmed by experiments and the like.

  According to the present invention, it is possible to provide an adhesive layer having excellent adhesiveness and an optical sheet having such an adhesive layer.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment, an example in which the present invention is applied to a prism sheet will be described. The prism sheet in the following embodiments has good transparency and light transmission, and prevents peeling of each layer at the time of manufacturing such as coating, transferring and conveying, and handling such as transportation, cutting and bonding. Therefore, excellent adhesiveness can be maintained even in a high temperature and high humidity environment.

  First, the manufacturing process of a prism sheet is demonstrated.

  FIG. 1 is a conceptual diagram showing a configuration of a prism sheet manufacturing apparatus 10 according to the present embodiment. The prism sheet manufacturing apparatus 10 includes a support supply unit 11, a coating unit 12, a drying unit 19, a nip roll 14, an embossing roll 13 that is a concavo-convex roll, a resin curing unit 15, and a peeling unit, which are sequentially arranged from upstream to downstream. A roll 16, a protective film supply unit 17, and a sheet winding unit 18 are provided.

  The support body supply unit 11 is configured by a feed roll or the like around which a sheet-like support body W (web) is wound, and functions as a sheet-like body supply unit that sequentially feeds the support body W.

  The support W of this embodiment is a sheet-like member in which a single-layer adhesive layer is laminated on a base (see FIG. 4 described later). In addition, the support body W may contain other layers, such as an antistatic layer and a protective layer, as needed.

  The application unit 12 is an apparatus that applies a resin to the surface of the support W and forms a resin layer F on the support W as shown in FIG. The resin layer F is a portion constituting a concavo-convex prism sheet provided as a final product, and a predetermined concavo-convex pattern is formed by the embossing roll 13 installed in the subsequent stage. Hereinafter, a sheet-like laminate composed of the support W and the resin layer F is referred to as “resin-coated sheet S”.

  The application unit 12 shown in FIG. 1 includes a radiation curable resin supply source 12A for storing resin, a resin supply pump 12B that sends resin from the radiation curable resin supply source 12A to the application head 12C, an application head 12C that discharges resin, And a support roller 12D that wraps and supports the support W to be coated with resin. Moreover, piping, a pump, etc. which send resin are provided among the radiation curing resin supply source 12A, the resin supply pump 12B, and the coating head 12C.

  A coating head 12C shown in FIG. 1 is an extrusion-type die coater, and discharges a resin liquid to be discharged stored in a liquid reservoir from a head end portion through a slit-like channel. The coating head 12C is not limited to the above-described extrusion type die coater, and any type of ejection head can be used, and the resin can be appropriately coated on the support W. Anything is possible.

  The resin discharged from the coating head 12C of this embodiment is a radiation curable resin, and is a type of resin that cures when irradiated with predetermined light (radiation) radiated from the resin curing unit 15 installed in the subsequent stage. is there.

  The drying unit 19 dries the resin layer F applied to the surface of the support W by the application unit 12. The degree of drying of the resin layer F by the drying unit 19 can be adjusted. For example, the degree of drying of the resin layer F in the resin coated sheet S is adjusted so that the transfer of the predetermined pattern by the embossing roll 13 installed in the subsequent stage is effectively performed.

  FIG. 3 is a diagram schematically showing a cross section along the axial direction of the rotation axis (C) of the embossing roll 13. As for the embossing roll 13 shown by FIG. 1 and FIG. 3, the fine uneven | corrugated predetermined pattern is formed in the surface. When such an embossing roll 13 is pressed against the resin layer F of the resin coated sheet S, a predetermined pattern of irregularities on the roll surface is transferred and formed on the resin layer F. For this reason, the embossing roll 13 is required to have the precision of the uneven pattern, the mechanical strength, the roundness, etc. adjusted appropriately. As such an embossing roll 13, for example, a metal rigid roll is preferable.

  The fine uneven pattern on the outer peripheral surface of the embossing roll 13 is required to be a shape pattern obtained by inverting the fine uneven pattern on the surface of the prism sheet provided as a product. Therefore, the fine uneven pattern on the outer peripheral surface of the embossing roll 13 needs to correspond to the fine uneven pattern on the surface of the prism sheet.

  As a method for forming a fine uneven pattern on the outer peripheral surface of the embossing roll 13, for example, a method of directly forming an uneven pattern on the outer peripheral surface by cutting with a single point diamond tool, photo etching, electron beam drawing, laser processing, etc. After embossing the surface of a thin metal plate with a concavo-convex pattern formed by photoetching, electron beam drawing, laser processing, stereolithography, etc. A method of using the roll 13 is exemplified. In addition, a concavo-convex pattern is formed on the surface of a material that is easier to process than metal by photoetching, electron beam drawing, laser processing, stereolithography, etc., and an inverted mold of this shape is formed by electroforming, etc. It is also possible to employ a method in which a metal plate-like body is prepared, and this plate-like body is wound around and fixed to the embossing roll 13 around the roll. In particular, when the reversal mold is formed by electroforming or the like, there is a feature that a plurality of plate-like bodies having the same shape can be obtained from one master (mother).

  Note that the surface of the embossing roll 13 is preferably subjected to a mold release treatment. By performing the mold release process on the surface of the embossing roll 13, the shape of the fine concavo-convex pattern is favorably maintained over a long period of time. As the mold release treatment, various known methods can be employed. For example, a coating treatment with a fluororesin is employed.

  As shown in FIG. 1, the nip roll 14 is a roll that pairs with the embossing roll 13 to press the resin layer F on the support W and transfers a predetermined uneven pattern of the embossing roll 13 to the resin layer F. Perform molding. For this reason, the nip roll 14 is required to have its mechanical strength, roundness, etc. adjusted appropriately. If the longitudinal elastic modulus (Young's modulus) of the surface of the nip roll 14 is too small, the roll forming process tends to be insufficient. On the other hand, when the longitudinal elastic modulus (Young's modulus) of the surface of the nip roll 14 is too large, the influence of foreign matters such as dust becomes large. Therefore, the longitudinal elastic modulus of the surface of the nip roll 14 is preferably set to an appropriate value.

  Arbitrary fine adjustment for adjusting the size of the gap between at least one of the embossing roll 13 and the nip roll 14 so that the gap (clearance) between the embossing roll 13 and the nip roll 14 can be accurately controlled. An apparatus is preferably provided. Moreover, it is preferable that at least one of the embossing roll 13 and the nip roll 14 is provided with an arbitrary pressure device so that a predetermined pressing force is applied between the embossing roll 13 and the nip roll 14.

  The resin curing unit 15 is light irradiation means provided so as to face the embossing roll 13 on the downstream side of the nip roll 14. The resin curing unit 15 emits light (radiation) having a wavelength corresponding to the curing characteristics of the resin layer F with a light amount corresponding to the conveyance speed of the resin coated sheet S. The light emitted by the resin curing unit 15 passes through the support W and cures the resin layer F. Thereby, the fine uneven | corrugated pattern transcribe | transferred to the resin layer F is fixed, and the prism layer 32 is formed (refer FIG. 4 mentioned later).

  As such a resin hardening part 15, the columnar lamp of the length substantially the same as the width | variety of the resin application sheet S is employable, for example. Note that a plurality of the cylindrical lamps may be provided in parallel, and a reflector may be provided on the back surface of the cylindrical lamp. Further, in the case where the resin layer F and the adhesive layer 34 are bonded using light irradiated from the resin cured portion 15, not only the curing characteristics of the resin layer F but also the adhesive characteristics of the resin layer F and the adhesive layer 34. Is irradiated from the resin curing unit 15.

  FIG. 4 is a diagram illustrating a cross-sectional configuration of a prism sheet 30 (resin-coated sheet S) including the prism layer 32 formed by the resin layer F. In the prism sheet 30 manufactured by the manufacturing apparatus 10 of the present embodiment, the base body 36, the adhesive layer 34, and the prism layer 32 are stacked from the bottom to the top.

  The peeling roll 16 shown in FIG. 1 is paired with the embossing roll 13 to peel the prism sheet 30 (resin coating sheet S) from the embossing roll 13. That is, the prism sheet 30 wound on the circumferential surface of the embossing roll 13 is sandwiched between the embossing roll 13 and the peeling roll 16 at the peeling portion and wound around the peeling roll 16. Thereby, the prism sheet 30 having the cured resin layer F on which the predetermined pattern is formed is peeled from the embossing roll 13 and sent to the subsequent stage.

  Such a peeling roll 16 is required to have its mechanical strength, roundness, etc. adjusted appropriately. Moreover, when the temperature of resin etc. rises by hardening, it is preferable to provide an arbitrary cooling device in the peeling roll 16 and to improve the peelability of the prism sheet 30 by cooling the prism sheet 30 at the time of peeling.

  Although not shown in the figure, the resin-coated sheet S (prism sheet) is placed between the location pressed by the nip roll 14 (position at 9 o'clock in FIG. 1) and the location released by the release roll 16 (position at 3 o'clock in FIG. 1). A plurality of backup rolls may be provided so as to face the embossing roll 13 wound around 30). In this case, since the curing process of the resin layer F is performed in a state where the resin coating sheet S is supported by the plurality of backup rolls and the embossing rolls 13, the predetermined uneven pattern of the embossing rolls 13 is accurately transferred to the resin layer F. .

  The sheet winding unit 18 includes a winding roll or the like that winds up the prism sheet 30 (resin coating sheet S), and winds and stores the prism sheet 30 that has been peeled off from the embossing roll 13. When the prism sheet 30 is stored by the sheet winding unit 18, the protective film H is supplied from the protective film supply unit 17 onto the prism sheet 30, and the support W, the resin layer F, and the protective film H overlap. In this state, the sheet is wound around the sheet winding unit 18.

  The protective film supply unit 17 is provided adjacent to the sheet winding unit 18 and supplies the protective film H onto the prism sheet 30 immediately before being wound by the sheet winding unit 18. In addition, the protective film H can use arbitrary things as needed.

  In the prism sheet manufacturing apparatus 10, a conveyance path for the resin coated sheet S (prism sheet 30) is formed between the coating unit 12 and the embossing roll 13, or between the peeling roll 16 and the sheet winding unit 18. A guide roller or the like may be installed, or a tension roller or the like that absorbs slackness during conveyance of the resin-coated sheet S may be installed.

  In the prism sheet manufacturing apparatus 10 having the above-described configuration, each roll is provided with an arbitrary drive device (not shown), and each roll is rotated in the direction of the arrow in the drawing by these drive devices. Be made.

  Next, a specific configuration of the prism sheet 30 will be described.

  Examples of the polyester resin constituting the film of the substrate 36 of the present embodiment (hereinafter appropriately referred to as polyester) include an aromatic dibasic acid or an ester-forming derivative thereof, a diol or an ester-forming derivative thereof, Linear saturated polyester synthesized from the above.

  Specific examples of the polyester that can be used in this embodiment include polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene-2,6-phthalene. Carboxylate, and the like. Polyethylene terephthalate, polyethylene naphthalate, and the like are particularly preferable from the viewpoints of availability, economy, and effects.

  Further, as a material for the substrate 36, a copolymer of the above-mentioned polyester, a blend of the copolymer and a small proportion of other resins, or the like can be used as long as the effects of the present invention are not impaired. Furthermore, this polyester film may contain a small amount of inorganic or organic fine particles in order to improve slipperiness, for example, an inorganic filler such as titanium oxide, calcium carbonate, silica, barium sulfate, silicone, acrylic In addition, an organic filler such as benzoguanamine, Teflon and epoxy, an adhesion improver such as polyethylene glycol (PEG) and sodium dodecylbenzenesulfonate, and an antistatic agent can be contained.

  The polyester film constituting the substrate 36 of the present embodiment is formed into a film by melt extrusion of the above-described polyester resin, and then oriented and crystallized by biaxial stretching in the machine direction and the transverse direction, and crystallized by heat treatment. Can be formed. As the production method and production conditions of these films, known methods and conditions can be appropriately selected.

  The thickness of the polyester film constituting the substrate 36 is not particularly limited and can be appropriately selected depending on the purpose of use of the film. When used for manufacturing the prism sheet 30, it is generally preferable to use a polyester film having a thickness of 5 μm to 500 μm as the substrate 36.

  The adhesive layer 34 that can be used in the present embodiment contains a styrene-butadiene copolymer (hereinafter abbreviated as “SBR” as appropriate) or a water-based urethane resin, and a crosslinking agent. SBR is a copolymer mainly composed of styrene and butadiene, and means a copolymer obtained by copolymerizing other components as required. By adjusting the content ratio of styrene and butadiene constituting the copolymer, SBR having various physical properties can be obtained.

  When the adhesive layer 34 is formed between the substrate 36 and the prism layer 32 as in the present embodiment, the styrene-butadiene copolymer is preferably latex. Specifically, Nipole (trade name) from Nippon Zeon, Nogatex (trade name) from Sumitomo Naugatac, Crosslen (trade name) from Takeda Pharmaceutical Company Limited, Asahi Dow Latex (trade name) from Asahi Dow, etc. In addition, commercially available products sold by Dainippon Ink and Chemicals, Inc. and overseas manufacturers can be used as the styrene-butadiene copolymer.

  When latex is used as the styrene-butadiene copolymer, the particle size of the dispersion particles is preferably 5 μm or less, more preferably 1 μm or less, and even more preferably 0.2 μm or less. When the particle diameter of the latex dispersion particles is large, the particles may aggregate in the coating step of the adhesive layer 34, or the transparency and gloss of the film may deteriorate. Therefore, the smaller the particle size of the latex dispersion particles, the better. In particular, when the adhesive layer 34 needs to be thin, it is preferable to reduce the particle diameter of the dispersion particles in accordance with the thickness of the adhesive layer 34.

  The content ratio of styrene / butadiene in the styrene-butadiene copolymer constituting the adhesive layer 34 is preferably about 50/50 to 80/20. The ratio of SBR contained in the latex is preferably 30% by weight to 50% by weight as the solid content weight.

  A cross-linking agent is added to the adhesive layer 34 in order to improve the physical properties of SBR. The cross-linking agent is preferably a triazine-based cross-linking agent.

  In the present embodiment, when the support W including the adhesive layer 34 and the substrate 36 is manufactured, the adhesive layer coating containing a styrene-butadiene copolymer and a crosslinking agent on the substrate 36 of the polyester resin film. After applying the liquid, it is preferable to form the easily adhesive support W by drying the adhesive layer coating liquid at a high temperature.

  As the water-based urethane resin constituting the adhesive layer 34, those having water-soluble or self-dispersing properties in which some hydrophilic groups or hydrophilic segments are added to the urethane resin are preferable. Further, a self-emulsifying water-based urethane resin containing a silanol group in the side chain can also be used. Specifically, Superflex (trade name) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. or Takerak (trade name) manufactured by Mitsui Takeda Chemical Co., Ltd. can be used. It is preferable to add a crosslinking agent to the urethane resin layer constituting the adhesive layer 34 in order to improve the physical properties of the urethane resin. The crosslinking agent used at this time is preferably a polyfunctional epoxy crosslinking agent (average number of epoxy functional groups: 3.5 to 6.5) or a carbodiimide crosslinking agent.

  When applying the adhesive layer coating liquid onto the polyester substrate 36, a known coating device can be used, for example, reverse coater, gravure coater, rod coater, air doctor coater, etc. (by Yuji Harasaki, It is possible to use an apparatus of “Coating Method” (see Shinsho Store, published in October 1979).

  The timing for applying the adhesive layer coating liquid onto the polyester substrate 36 is preferably before biaxial stretching, after biaxial stretching, or just before coating the surface layer material. Further, an adhesive layer coating solution is applied to a polyester adhesive layer 34 (for example, see Japanese Patent Publication No. 41-8470) manufactured by uniaxial stretching by a roll stretching method, and the adhesive layer coating solution is appropriately applied. Immediately after drying or without drying the adhesive layer coating solution, the adhesive layer 34 coated with the adhesive layer coating solution is stretched in a direction perpendicular to the uniaxial stretching direction. A method of heat-treating the adhesive layer 34 can also be used (hereinafter referred to as “coating stretching method”). According to this coating stretching method, the adhesive layer 34 can be dried simultaneously with stretching, and the adhesive layer 34 is sufficiently stretched. As a result, the adhesive layer 34 can be formed thin, and a wide laminated film (the adhesive layer 34 and the substrate 36), which has been difficult by a method other than the coating stretching method, can be obtained.

  The thickness of the adhesive layer 34 on the substrate 36 is preferably in the range of 0.01 μm to 0.5 μm. When the thickness of the adhesive layer 34 is less than 0.01 μm, it is difficult to uniformly apply the adhesive layer 34 on the substrate 36, so that uneven application tends to occur, and the prism layer 32 and the adhesive layer 34 are not easily coated. Adhesion tends to be insufficient. On the other hand, if the thickness of the adhesive layer 34 exceeds 0.5 μm, there is a possibility that the layers are easily fixed to each other or the light transmittance of the prism sheet 30 is lowered.

  The adhesive layer 34 and the substrate 36 are, as necessary, an adhesion improving agent, a coating property improving agent, an antifoaming agent, an ultraviolet absorber, an antioxidant, an antistatic agent, a lubricant, an inorganic fine particle, a dye, a pigment, Etc. may be included.

  In order to evaluate the adhesiveness of the support W thus obtained, for example, a tape peeling test can be performed after the ultraviolet curable resin layer is formed on the surface of the adhesive layer 34. It is desirable that the support W has such a strength that peeling does not occur at any interface between adjacent layers in the tape peeling test.

  The adhesive layer 34 of this embodiment is formed on at least one side of a polyester film substrate 36. In particular, the adhesive layer 34 is formed on both surfaces of the base 36 when it is necessary for the function of the support W to have easy adhesion on both surfaces of the support W.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. Forms can also be included within the scope of the present invention.

  Next, specific examples based on the above-described embodiment will be described. The following examples are mainly implemented based on the above-described embodiment, and description of the same contents as those described above is omitted. In addition, the following Examples are illustrations and this invention is not limited to the following Examples.

Example 1
(Preparation of substrate)
Prepared PET (polyethylene terephthalate) pellets with a phenol / tetrachloroethane weight ratio of “phenol / tetrachloroethane = 6/4” and an intrinsic viscosity of 0.66 measured in an environment at 25 ° C. did. The PET pellets were dried at 130 ° C. for 4 hours, melted at 300 ° C., extruded from a T-die, and then rapidly cooled to prepare an unstretched film having a thickness after heat setting of 100 μm. This unstretched film was longitudinally stretched 3.3 times by rolls having different peripheral speeds, and then stretched 4.5 times by a tenter. The environmental temperature during longitudinal stretching was 110 ° C., and the environmental temperature during lateral stretching was 130 ° C. Thereafter, the stretched film was heat-set at 240 ° C. for 20 seconds, and then the stretched film was relaxed by about 4% in the transverse direction at the same temperature. And the slit was formed in the chuck | zipper part of a tenter, the knurl process was given to the both ends of the slit, and the film was wound up in the ratio of 4 kg / cm < ² >. In this way, a roll of the substrate 36 having a width of 2.4 m, a length of 5000 m, and a thickness of 180 μm was obtained.

(Process before application of adhesive layer)
Prior to application of the adhesive layer coating solution, the following surface treatment was performed. Using a solid state corona treatment machine 6KVA model manufactured by Pillar, both surfaces of the substrate 36 were treated at a rate of 20 m / min in the length direction at room temperature. From the current and voltage readings at this time, it was found that the substrate 36 was treated at 0.375 kV · A · min / m ² . The treatment frequency at this time was 9.6 kHz, and the gap clearance between the electrode and the dielectric roll was 1.6 mm. An adhesive layer 34 composed of the two layers described below was applied on the substrate 36 subjected to such treatment.

An adhesive layer coating solution having the following components was applied to one side of the substrate 36 at a rate of 6 ml / m ² and dried at 185 ° C. for 5 minutes to form an adhesive layer 34 having a thickness of 0.15 μm. Formed on top. In this example, “butadiene-styrene copolymer latex” is used as a styrene-butadiene copolymer, and “2,4-dichloro-6-hydroxy-S-triazine sodium salt” is used as a dichloro-s-trialine derivative. Utilized.

(Composition of coating solution for adhesive layer)
Butadiene-styrene copolymer latex (solid content 43%, butadiene / styrene weight ratio = 32/68) 13 ml
2,4-dichloro-6-hydroxy-S-triazine sodium salt 8% aqueous solution 7 ml
0.5 ml of 2% aqueous solution of polystyrene particles (average particle size: 1.8 μm)
9.5 ml of distilled water
(Preparation of prism layer)
(Preparation of resin solution)
The compounds shown in FIG. 5 were mixed in the weight ratio shown in FIG. 5, heated to 50 ° C., and each compound was dissolved and mixed by stirring to obtain a resin liquid for the prism layer 32. In FIG. 5, “EB3700”, “BPE200”, “BR31”, “LR8883X”, and “MEK” indicate compounds contained in the resin liquid constituting the prism layer 32. “MEK content” indicates the MEK content in the resin liquid constituting the prism layer 32, and “liquid viscosity” indicates the viscosity of the resin liquid. The names and contents of each compound are as follows.

EB3700: Everkrill 3700, manufactured by Daicel UC Corporation,
Bisphenol A type epoxy acrylate (viscosity 2200mPa · s, 65 ° C)
BPE200: NK ester BPE-200, manufactured by Shin-Nakamura Chemical Co., Ltd.
Ethylene oxide-added bisphenol A methacrylate (viscosity 590 mPa · s, 25 ° C)
BR-31: New Frontier BR-31, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Tribromophenoxyethyl acrylate (solid at room temperature, melting point 50 ° C or higher)
LR8883X: Lucirin LR8883X,
Photo radical generator manufactured by BASF Corporation,
Ethyl-2,4,6-trimethylbenzoylethoxyphenylphosphine oxide MEK: methyl ethyl ketone (formation of prism layer)
The prism layer 32 (resin layer F) was formed on the support W using the prism sheet manufacturing apparatus 10 shown in FIG.

  The width of the support W was 500 mm.

  As the embossing roll 13, a roll having a length in the width direction of the sheet W of 700 mm, a diameter of 300 mm, made of S45C and having a surface material of nickel was used. Grooves having a pitch of 50 μm in the roll axis direction were formed on the entire circumference of the surface of the embossing roll 13 by a cutting process using a diamond tool (single point). The cross-sectional shape of the groove was a triangular shape with an apex angle of 90 degrees, and the bottom of the groove was a triangular shape with a 90 degree without a flat portion. That is, the groove width was 50 μm and the groove depth was about 25 μm. This groove was formed in an endless shape without a seam in the circumferential direction of the embossing roll 13. A prism lens (prism layer 32) was formed on the resin layer F by the embossing roll 13 having such grooves. The surface of the embossing roll 13 was subjected to nickel plating after the groove processing.

  As the coating unit 12, a die coater including an extrusion type coating head 12C was used.

  As the resin liquid constituting the resin layer F, each liquid shown in FIG. 5 was used. In addition, the sample used by each Example and each comparative example was manufactured based on the combination of the resin liquid and traveling speed which are shown in FIG. 6 mentioned later.

  The amount of resin liquid supplied to the coating head 12C was controlled by the resin supply pump 12B so that the film thickness of the resin layer F after drying the organic solvent was 20 μm.

  In the drying unit 19, a hot air circulation type drying device was used. The temperature of the hot air was 100 ° C.

  As the nip roll 14, a roll having a surface of a silicon rubber layer having a diameter of 200 mm and a rubber hardness of 90 was used. The effective nip pressure when pressing the resin coating sheet S (support W and resin layer F) with the embossing roll 13 and the nip roll 14 was set to 0.5 Pa.

A metal halide lamp was used as the resin curing part 15, and light having an energy of 1000 mJ / cm ² was emitted from the resin curing part 15.

  As described above, a prism sheet 30 according to Example 1 was obtained.

(Example 2)
An adhesive layer coating solution having the following components was applied to one side of the substrate 36 at a rate of 6 ml / m ² and dried at 185 ° C. for 5 minutes to form an adhesive layer 34 having a thickness of 0.15 μm. Formed on top. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

(Composition of coating solution for adhesive layer)
30% aqueous dispersion of Takelac W6061 (water-based urethane resin manufactured by Mitsui Takeda Chemical Company) 7.9 ml
Denacol EX-521 (manufactured by Nagase ChemteX) 100% 0.5ml
0.5 ml of 2% aqueous solution of polystyrene particles (average particle size: 1.8μ)
Emarex 710 (Nippon Emulsion Polyoxyethylene alkyl ether) 1% 0.7ml
Distilled water 90.4ml
(Example 3)
An adhesive layer coating solution having the following components was applied to one side of the substrate 36 at a rate of 6 ml / m ² and dried at 130 ° C. for 5 minutes to form an adhesive layer 34 having a thickness of 0.15 μm. Formed on top. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W. In this example, “carbodilite V-02-L2” was used as a carbodiimide-based crosslinking agent.

(Composition of coating solution for adhesive layer)
Superflex 460 (Daiichi Kogyo Seiyaku Co., Ltd. water-based urethane resin) 38% 6.2 ml
0.3 ml of 2% aqueous solution of polystyrene particles (average particle size: 1.8μ)
Carbodilite V-02-L2 (Nisshinbo Co., Ltd.) Solid content 40% 1.6 ml
Distilled water 90.4ml
(Comparative Example 1)
As a coating solution for the adhesive layer constituting the adhesive layer 34, a coating solution having the following composition from which the crosslinking agent was removed was used. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

Butadiene-styrene copolymer latex (solid content 43%, butadiene / styrene weight ratio = 32/68) 13 ml
Polystyrene particles (average particle size: 1.8μ) 2% aqueous solution 0.5 ml
Distilled water 79.5ml
(Comparative Example 2)
The drying temperature of the adhesive layer coating solution (adhesive layer 34) applied to the substrate 36 was 130 ° C. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

(Comparative Example 3)
As the adhesive layer coating liquid constituting the adhesive layer 34, a coating liquid having the following composition in which the urethane resin was changed to an acrylic resin was used. The other points were the same as in Example 2 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

Julimer ET-410 (Nippon Pure Chemicals acrylic resin) 30% aqueous dispersion 7.9ml
Denacol EX-521 (manufactured by Nagase ChemteX) 100% 0.5ml
Polystyrene particles (average particle size: 1.8μ) 2% aqueous solution 0.5 ml
Emarex 710 (Nippon Emulsion Polyoxyethylene alkyl ether) 1% 0.7ml
Distilled water 90.4ml
(Comparative Example 4)
As the adhesive layer coating liquid constituting the adhesive layer 34, a coating liquid having the following composition from which carbodiimide was removed was used. The other points were the same as in Example 3 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

Superflex 460 (Daiichi Kogyo Seiyaku Co., Ltd. water-based urethane resin) 38% 6.2 ml
Polystyrene particles (average particle size: 1.8μ) 2% aqueous solution 0.3 ml
Distilled water 90.4ml
(Comparative Example 5)
The support W used in Example 1 was used as the first layer, and a second layer having the following configuration was formed on the first layer. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

(Configuration of the second layer)
An undercoat liquid having the following composition was applied on the support W (first layer) having the easy adhesion property used in Example 1. Specifically, the undercoat liquid was applied onto the first layer at a rate of 9 ml / m ² using a wire bar. And the undercoat liquid apply | coated on the 1st layer was dried for about 5 minutes in 175 degreeC environment. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

Gelatin 0.9g
Acetic acid 10% 0.5ml
98.6ml of distilled water
(Comparative Example 6)
The corona treatment was not performed before applying the adhesive layer coating solution (adhesive layer 34) onto the substrate 36. Other points were the same as in Example 1 described above, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

(Comparative Example 7)
A coating solution for an adhesive layer containing the following composition in which the epoxy crosslinking agent (Denacol EX-521) of Example 2 described above was changed was used. The other points were the same as in Example 2, and a prism sheet 30 was obtained using a film having easy adhesion as a support W.

(Composition of coating solution for adhesive layer)
Takelac W6061 (Mitsui Takeda Chemical's water-based urethane resin) 30% aqueous dispersion
7.9ml
Denacol EX-313 (manufactured by Nagase ChemteX) 100% 0.5ml
Polystyrene particles (average particle system: 1.8 μm) 2% aqueous solution 0.5 ml
EMALEX 710 (Nippon Emulsion Polyoxyethylene alkyl ether) 1% 0.7ml
Distilled water 90.4ml
(Evaluation of easy adhesive film)
FIG. 6 shows the peelability of the support W. In FIG. 6, “easy-adhesive layer main component” indicates the main component of the adhesive layer 34, and “drying temperature” indicates the drying temperature of the adhesive layer 34.

(Adhesive evaluation during transfer: Transfer peeling test)
In the above-described Examples and Comparative Examples, when the prism layer 32 was formed in the prism sheet manufacturing apparatus 10, the residual amount of the UV curable resin that did not adhere to the support W and adhered to the embossing roll 13 was measured. In FIG. 6, the case where no UV curable resin remains on the embossing roll 13 is indicated by ◯, the case where the UV curable resin partially remains on the embossing roll 13 is indicated by △, and the UV curable resin is the entire surface of the embossing roll 13. What remained was shown by x.

(Product adhesion evaluation: Tape peel test)
Eleven cuts were formed on the surface of the obtained prism sheet 30 with an NT cutter. Each of these cuts was cross-cut to a depth of 1 mm to a depth penetrating the polyester film (base 36). Then, a cellophane tape (cello tape: manufactured by Nichiban Co., Ltd.) was affixed to the entire surface of the subject, and a peel test was performed to remove the cellophane tape. This peeling test was repeated three times in the prism ridge line direction and the prism parallel direction. And the number of the cut pieces of the prism layer 32 which adhered to a cellophane tape and peeled was measured. In FIG. 6, the case where no separation of the prism layer 32 occurred is indicated by ◯, the case where the separation of the prism layer 32 partially occurred is indicated by △, and the separation of the prism layer 32 is performed over the entire surface of the cellophane tape. What occurred was indicated by a cross.

  As is apparent from FIG. 6, in Examples 1 to 3 according to the above-described embodiment, the support W is excellent in adhesiveness with the prism layer 32 formed on the surface, and the polyester film base 36, adhesive layer No peeling phenomenon was observed between 34 and the prism layer 32. In addition, it was confirmed by visual observation that all of the supports W according to Examples 1 to 3 have high light transmittance.

(Environmental reliability)
FIG. 7 shows conditions for the environmental reliability test of the prism sheet 30. In FIG. 7, “item” indicates an environmental element to be tested, and “condition” indicates a specific test condition. In addition, “normal humidity” in FIG. 7 is the humidity in the room where the test was performed, specifically 50%. In FIG. 7, a case where peeling of each layer constituting the prism sheet 30 did not occur at all is indicated by ◯, a case where peeling of each layer partially occurred is indicated by a triangle, and the peeling of each layer occurred over the entire surface of the cellophane tape. What occurred was indicated by a cross.

  As is clear from FIG. 7, in any of the prism sheets 30 of Examples 1 to 3 according to the above-described embodiment, no peeling of each layer constituting the prism sheet 30 occurred. Therefore, it was confirmed that the prism sheet 30 according to the above-described embodiment has excellent adhesiveness that is strong against environmental changes.

  As described above, the easy-adhesive support W according to the above-described embodiment is a binder used for various paints including a photo-curing resin, an adhesive, or a photosensitive layer, for example, even in a high-temperature and high-humidity atmosphere. Excellent adhesion to resin etc. Moreover, the easily-adhesive support W according to the above-described embodiment has an excellent effect that the transparency and light transmittance are good. Therefore, according to the above-described embodiment, it is possible to produce a high-quality prism sheet in which the adhesiveness between the support W and the prism layer 32 is kept good.

It is a conceptual diagram which shows the structure of the manufacturing apparatus of the prism sheet which concerns on this embodiment. It is a figure which shows the cross-sectional structure of a support body and a resin layer. It is a figure which shows the outline of the cross section along the axial direction of the rotating shaft of an embossing roll. It is a figure which shows the cross-sectional structure of the prism sheet containing the prism layer formed of a resin layer. An example of the resin liquid which comprises a resin layer is shown. The peelability of the support is shown. The conditions of the environmental reliability test of the prism sheet are shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Manufacturing apparatus of a prism sheet, 11 ... Support body supply part, 12 ... Application | coating part, 12A ... Radiation curable resin supply source, 12B ... Resin supply pump, 12C ... Application | coating head, 12D ... Support roller, 13 ... Embossing roll, 14 Nip roll, 15 resin curing part, 16 peeling roller, 17 protective film supply part, 18 sheet take-up part, 19 drying part, 30 prism sheet, 32 prism layer, 34 adhesive layer, 36 Base, W ... support, F ... resin layer, S ... resin-coated sheet

Claims (10)

An optical sheet comprising an adhesive layer provided between the first layer and the second layer, for bonding the first layer and the second layer,
The optical sheet contains a styrene-butadiene copolymer and a dichloro-s-trialine derivative, and is formed by drying at a temperature of 130 ° C. or higher. An optical sheet comprising an adhesive layer provided between the first layer and the second layer, for bonding the first layer and the second layer,
The adhesive sheet contains an aqueous urethane resin and an epoxy crosslinking agent having an average epoxy functional group number of 3.5 or more, and is formed by drying at a temperature of 150 ° C. or more. An optical sheet comprising an adhesive layer provided between the first layer and the second layer, for bonding the first layer and the second layer,
The adhesive sheet contains an aqueous urethane resin and a carbodiimide crosslinking agent, and is formed by drying at a temperature of 120 ° C. or higher.   The optical sheet according to claim 1, wherein the adhesive layer is a single layer.   The optical sheet according to any one of claims 1 to 4, wherein the first layer is a polyester film.   6. The adhesive layer according to claim 1, wherein the adhesive layer is provided on the first layer that has been subjected to at least one of a corona treatment, a plasma treatment, a glow discharge treatment, and an ultraviolet treatment. An optical sheet according to crab.   The optical sheet according to claim 1, wherein the second layer is a prism layer. A method of manufacturing an adhesive layer that bonds the first layer and the second layer by being disposed between the first layer and the second layer,
Preparing a solution for an adhesive layer containing a styrene-butadiene copolymer and a dichloro-s-trialine derivative;
Drying the adhesive layer solution at a temperature of 150 ° C. or higher;
The manufacturing method of the contact bonding layer characterized by the above-mentioned. A method of manufacturing an adhesive layer that bonds the first layer and the second layer by being disposed between the first layer and the second layer,
A step of preparing a solution for an adhesive layer containing an aqueous urethane resin and an epoxy crosslinking agent having an average epoxy functional group number of 3.5 or more;
Drying the adhesive layer solution at a temperature of 150 ° C. or higher;
The manufacturing method of the contact bonding layer characterized by the above-mentioned. A method of manufacturing an adhesive layer that bonds the first layer and the second layer by being disposed between the first layer and the second layer,
Preparing an adhesive layer solution containing a water-based urethane resin and a carbodiimide-based crosslinking agent;
Drying the adhesive layer solution at a temperature of 120 ° C. or higher;
The manufacturing method of the contact bonding layer characterized by the above-mentioned.

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