JP2013119177A - Shaped sheet, resin-coated shaped sheet, and method for producing optical sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaped sheet which is excellent in shape reproducibility even when a complicated and finely-rugged shape is formed thereon and which can allow deformation of a rugged shape of an optical film or warp of the whole optical sheet to be prevented or reduced when the optical sheet is molded by using the shaped sheet or when the shaped sheet is peeled from the optical sheet and to provide a resin-coated shaped sheet and a method for producing the optical sheet by using the shaped sheet.SOLUTION: The shaped sheet is obtained by layering a finely rugged layer on a base material. The finely rugged layer comprises a cured product of a finely-rugged layer formation resin composition containing an acrylate-based ionizing radiation-curable resin and a phosphate-based mold release agent, at the least. The cured product has ≥2B pencil hardness when measured at 20 g load according to JIS K 5600-5-4.

Description

  The present invention relates to a shaping sheet, a resin-coated shaping sheet, and a method for producing an optical sheet using the shaping sheet.

Liquid crystal display devices (LCDs) are thinner and lighter than existing cathode ray tube (CRT) image display devices, and are now widely used. The LCD is composed of a panel (liquid crystal panel), which is a central unit for generating and controlling images, and a surface light source device (backlight unit) provided on the back side of the liquid crystal panel. Depending on the light position, there are edge light type and direct type. The edge light type surface light source device includes a light guide plate and the like in addition to the light source, and the light sent from the light source is guided toward the end face while being scattered and reflected in the light guide plate. The light is gradually emitted from the light exit surface.
In recent years, with increasing demands for reducing power consumption and improving the brightness of display screens, how to efficiently irradiate liquid crystal panels with illumination light from a light source has become a major issue. Conventionally, cold cathode fluorescent lamps (CCFLs) have been the mainstream as light sources, but because of their excellent color reproducibility, miniaturization, and low power consumption, more and more light emitting diodes (LEDs) are used as light sources. ing. In the case of a light source that has high light rectilinearity, such as an LED light source, light is diffused by a method of diffusing light by printing or mat-concave pattern like the conventional light guide plate to emit light from the light guide plate. It was difficult to efficiently collect light in the normal direction of the light exit surface. In view of this, a light guide plate has been proposed in which a fine uneven shape such as a prism shape or a lens shape is formed on the surface of the light guide plate to reduce diffusion of emitted light.

  In addition to the light guide plate, an optical sheet having a concavo-convex shape on its surface, such as a prism sheet, a lens sheet, and an antireflection sheet having a nano fine concavo-convex shape, is used in an image display device such as an LCD. Yes. These optical sheets express a desired function by modulating light by geometric optical action such as refraction or reflection, or by wave optical action such as diffraction. The shape is determined. In order to increase the functionality of an optical sheet, an optical sheet having a very uneven shape, an asymmetric shape, or a complicated uneven shape such as a moth-eye structure is required.

However, in the conventional injection molding and extrusion molding adopted as a method for producing an optical sheet, the shape reproducibility of the uneven shape is insufficient, and in the case of forming a complicated uneven shape, the unevenness of the optical sheet Part of the shape may be chipped or bubbles may be generated at the top of the uneven portion of the optical sheet, making it difficult to mold accurately and accurately. In addition, the injection molding has a problem that it is difficult to produce a large or thin product. On the other hand, the 2P method in which a UV resin is molded with a mold has good moldability reproducibility, but is inferior in productivity when producing a thick sheet product and is not suitable for mass production.
In addition, an optical sheet having a function of guiding light like a light guide plate is required to have no distortion in the optical sheet, but in conventional extrusion molding, a plate shape that cannot be bent like a light guide plate. When the optical sheet is peeled off from the mold before the resin is completely cooled, there is a problem in that the resulting optical sheet is likely to be deformed into a concavo-convex shape or optically distorted.

  As a measure for improving the method by extrusion molding, for example, Patent Document 1 discloses a method of using a metal belt mold instead of a roll metal mold at the time of extrusion molding. Patent Document 2 and Patent Document 3 disclose an extrusion method using a resin-made shaping sheet.

  However, the method disclosed in Patent Document 1 is a method in the case where the uneven shape to be shaped is a shallow uneven shape or a simple shape. The methods disclosed in Patent Documents 2 and 3 have a step of winding a sheet material during the manufacturing process, and can be applied to the manufacture of a non-bent plate-like optical sheet such as a light guide plate. Can not. In addition, in any of these Patent Documents 1 to 3, there is no mention of preventing deformation of the concavo-convex shape of the optical sheet or distortion of the entire optical sheet that occurs when the mold or the shaping sheet is peeled from the optical sheet. Absent.

JP-A-56-157310 Japanese Patent Laid-Open No. 8-211205 JP 2001-225376 A

  The present invention has been made to solve the above problems, and is excellent in mold reproducibility even when it is desired to form a complicated fine concavo-convex shape, and peels the mold sheet from the optical sheet during molding with the mold sheet. Providing a molding sheet and a resin-coated molding sheet that can prevent or reduce deformation of the irregular shape of the optical sheet and distortion of the entire optical sheet, and a method for producing an optical sheet using the molding sheet The purpose is to do.

The shaping sheet according to the present invention is a shaping sheet in which a fine uneven layer is laminated on a substrate,
The fine concavo-convex layer is made of a cured product of a resin composition for forming a fine concavo-convex layer containing at least an acrylate ionizing radiation curable resin and a phosphate ester-based release agent, and is JIS K5600-5-4 after curing. The pencil hardness (20 g load) specified in 1 is 2B or more.

  In the moldable sheet according to the present invention, the resin composition for forming a fine concavo-convex layer comprises 80% by weight or more of the acrylate ionizing radiation curable resin and 0.03 to 0.70% by weight of the phosphate ester-based release agent. It is preferable that a monomer is contained and the monomer content in the acrylate ionizing radiation curable resin is 80 to 98% by weight.

  In the shaped sheet according to the present invention, the concavo-convex shape of the fine concavo-convex layer has a portion in which the ratio of height to pitch (height / pitch) is 1/5 or more and the deepest reaching portion of the concave portion has a spire shape. Can be.

  In the shaping sheet according to the present invention, a plurality of concave and convex shapes of the fine concave and convex layers are arranged on the same surface in a direction perpendicular to the extending direction of groove-shaped unit concave and convex structures obtained by inverting the side surfaces of the columnar shape. Or a shape obtained by inverting the moth-eye structure of the nanometer order.

  In the shaped sheet according to the present invention, it is preferable from the viewpoint of quality control that the base material and the fine uneven layer are formed of a light transmissive material.

  The resin-coated shaped sheet according to the present invention is formed by laminating a melted thermoplastic resin on the concavo-convex surface of the fine concavo-convex layer of the shaped sheet according to the present invention. It is a feature.

  The resin-coated shaped sheet according to the present invention has a peel strength (based on JIS K6854) of 25 mm width and a peeled-off 90 ° measurement of 0.01 N or more and 1 N when the molded sheet and the resin layer are peeled off. It is preferable from the point which is excellent in shaping reproducibility.

The method for producing an optical sheet according to the present invention comprises forming a resin layer by laminating a molten thermoplastic resin on the concavo-convex surface of the fine concavo-convex layer of the molding sheet according to the present invention, and applying a resin coating. Forming a mold sheet, a resin-coated molded sheet forming step;
A molding sheet peeling step, which obtains an optical sheet by peeling the molding sheet from the resin-coated molding sheet,
The peeling strength (based on JIS K6854) when peeling the shaping sheet from the resin-coated shaping sheet is 0.01 N or more and less than 1 N in the measurement of 25 mm width and 90-degree peeling.

  The optical sheet manufacturing method according to the present invention can use the optical sheet as a light guide plate.

  In the method for producing an optical sheet according to the present invention, the concavo-convex shape formed on the surface of the optical sheet can have a moth-eye structure.

  According to the present invention, even when it is desired to form a complicated fine uneven shape, the reproducibility of forming is excellent, and the uneven shape of the optical sheet generated when the forming sheet is peeled off from the optical sheet during molding with the forming sheet. It is possible to provide a molding sheet and a resin-coated molding sheet that can prevent or reduce deformation and distortion of the entire optical sheet, and further provide a method for producing an optical sheet using the molding sheet. it can.

It is a schematic perspective view which shows an example of the shaping sheet which concerns on this invention. It is a figure explaining an example of the manufacturing method of the shaping sheet which concerns on this invention. It is the schematic explaining an example of the manufacturing method of the optical sheet which concerns on this invention. It is the schematic which shows an example of the apparatus used for the manufacturing method of the optical sheet which concerns on this invention. It is the schematic which shows another example of the apparatus used for the manufacturing method of the optical sheet which concerns on this invention.

  Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the spirit thereof.

In the present invention, (meth) acrylic resin represents acrylic resin and / or methacrylic resin, and (meth) acrylate represents acrylate and / or methacrylate.
In the present invention, the resin is a concept including a polymer in addition to a monomer and an oligomer.
In the definition of film and sheet in JIS-K6900, a sheet is thin and generally refers to a flat product whose thickness is small for the length and width, and the film is extremely thick compared to the length and width. A thin, flat product that is small and has an arbitrarily limited maximum thickness, typically supplied in the form of a roll. Therefore, it can be said that a film having a particularly thin thickness among the sheets is a film, but the boundary between the sheet and the film is not clear and is difficult to distinguish clearly. Therefore, in the present invention, the meaning of both a thick sheet and a thin sheet is meant. Is defined as “sheet”. In the present invention, a plate-like member that cannot be bent is also included in the “sheet”. In the present invention, the term “plate-like” does not mean that it does not bend completely, but it means that it does not bend so that it can be wound, and it may be bent by applying a load.
In the present invention, the molecular weight means a weight average molecular weight which is a polystyrene equivalent value measured by gel permeation chromatography (GPC) in a THF solvent when having a molecular weight distribution, and when having no molecular weight distribution, It means the molecular weight of the compound itself.

(Molding sheet)
The shaping sheet according to the present invention is obtained by laminating a fine concavo-convex layer on a substrate, and the fine concavo-convex layer comprises at least an acrylate ionizing radiation curable resin and a phosphate ester release agent. The pencil hardness (20 g load) prescribed | regulated to JISK5600-5-4 after hardening consists of hardened | cured material of the resin composition for fine uneven | corrugated layer formation containing, It is characterized by the above-mentioned.
When an optical sheet is manufactured by extrusion molding using a conventional shaped sheet, when forming a complex uneven shape, the details of the uneven portion of the shaped sheet, especially the thermoplastic for forming the optical sheet at the deepest part The resin is not filled, and uneven portions may be chipped or bubbles may be generated, which makes it difficult to mold accurately and accurately. Also, when peeling the shaping sheet from the optical sheet, because the peel strength is too strong, if the uneven shape of the optical sheet is deformed or the optical sheet is a plate that cannot be bent, the entire optical sheet In some cases, distortion occurred.
Therefore, as a result of intensive studies, the present inventors have determined that the fine uneven layer which is the uneven portion of the shaping sheet is a fine uneven layer containing at least an acrylate ionizing radiation curable resin and a phosphate ester release agent. By making the cured product of the resin composition for formation and the pencil hardness (20 g load) defined in JIS K5600-5-4 after curing 2B or more, the mold sheet is complicated and fine. It has been found that even when it is desired to form a concavo-convex shape, the mold reproducibility is excellent, and the deformation of the concavo-convex shape of the optical sheet and the distortion of the entire optical sheet that occur when the molded sheet is peeled can be prevented or reduced. This is because the fine concavo-convex layer is formed using the resin composition for forming the fine concavo-convex layer of the present invention, and the hardness of the fine concavo-convex layer is set to the hardness specified by the present invention, whereby the concavo-convex of the fine concavo-convex layer It is considered that the thermoplastic resin can be filled without generating bubbles to the details of the portion, and that the peel strength when peeling the shaped sheet from the cured thermoplastic resin becomes appropriate.
In addition, when extrusion molding is performed using a metal mold that has been widely used in the past, the thermoplastic resin is filled into the mold, and at the same time, the temperature of the thermoplastic resin decreases due to the temperature difference between the thermoplastic resin and the mold. As a result, since the fluidity is also impaired, there is a problem that the resin is not sufficiently filled in the uneven portions of the mold and the moldability is poor. However, the moldable sheet according to the present invention has a high heat insulating effect because the fine concavo-convex layer is formed by using the specific resin composition for forming the fine concavo-convex layer, and the thermoplastic resin is used for the moldable sheet. Even if the uneven portions are filled, the temperature does not drop immediately and the fluidity is maintained, so that the mold reproducibility is good.

In FIG. 1, the schematic perspective view of the shaping sheet 1 by which the fine uneven | corrugated layer 3 was laminated | stacked on the base material 2 as an example of the shaping sheet which concerns on this invention is shown.
Hereinafter, the base material and the fine concavo-convex layer of the molding sheet according to the present invention and the entire molding sheet will be described in detail, and further, the method for producing the molding sheet according to the present invention will be described.

A. Base material The base material which the shaping sheet which concerns on this invention has has a role as a support body of a shaping sheet. It does not specifically limit as said base material, A well-known resin-made base material can be used, It is preferable that it is a light-transmitting resin base material especially. This is because when the base material is light transmissive, foreign substances and bubbles can be visually inspected when producing the shaping sheet, and quality control becomes easy. Moreover, when the base material which a shaping | molding sheet has is light-transmitting and a fine uneven | corrugated layer is also light-transmitting, quality control at the time of producing an optical sheet using the said shaping | molding sheet becomes easy.
The light-transmitting resin is not particularly limited, and examples thereof include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polycarbonate (PC) and polymethyl methacrylate (PMMA), and cellulose triacetate (TAC). Cellulose resins, olefin resins and the like can be mentioned, and among them, PET is preferable.
The base material is not particularly limited, but is preferably a biaxially stretched resin base material because of excellent heat resistance.

  Although the said base material is not specifically limited, From a viewpoint of quality control, it is preferable that a total light transmittance is 80% or more, and it is more preferable that it is 90% or more. The total light transmittance can be measured with a haze meter.

  Further, as the base material, the resin composition for forming a fine concavo-convex layer laminated on the base material is cured even when ionizing radiation is irradiated from the base material side when manufacturing the shaping sheet. It is preferable to use what can be made.

  Although the said base material is not specifically limited, It is preferable that the heat resistance measured by JISK7206 is 100 degreeC or more, and it is especially preferable that it is 120 degreeC or more. It is because there exists a possibility that a base material may deform | transform in the manufacture process of a shaping sheet as the heat resistance of a base material is less than 100 degreeC.

  Although the thickness of the said base material is not specifically limited, From a viewpoint of handleability and cost, it is 50-250 micrometers normally.

B. Fine concavo-convex layer The fine concavo-convex layer of the shaping sheet according to the present invention has a concavo-convex shape on the surface thereof, and the concavo-convex shape can be an original plate having a concavo-convex shape formed on the surface of the optical sheet. In the present invention, the “original plate” means a mold in which a raw material is poured in order to mold an inverted shape to be fitted. The “inverted shape” means a shape in which one concavo-convex convex portion and the other concavo-convex concave portion can be fitted to each other without a gap. Therefore, the uneven | corrugated shape which the fine uneven | corrugated layer of a shaping sheet has is made into the shape which reversed the uneven | corrugated shape formed in the surface of an optical sheet.
The fine concavo-convex layer is made of a cured product of a resin composition for forming a fine concavo-convex layer containing at least an acrylate ionizing radiation curable resin and a phosphate ester-based release agent, and is cured JIS K5600-5-4. The pencil hardness (20 g load) specified in 1 is 2B or more. Thereby, the said fine uneven | corrugated layer becomes the thing excellent in heat resistance and shaping reproducibility.
This is an ionizing radiation curable resin that is excellent in heat resistance and has an appropriate hardness. In addition, among release agents, a phosphate ester type mold release having an ester group in the same manner as an acrylate resin. This is thought to be due to the combination of agents. By combining an acrylate resin having an ester group and a phosphate ester release agent in common, the release agent bleeds out to the surface of the fine uneven layer while being uniformly dispersed in the resin composition. Thereby, it is possible to fill the thermoplastic resin without generating bubbles up to the details of the concavo-convex portion of the fine concavo-convex layer, and the fine concavo-convex layer is appropriate for the thermoplastic resin laminated on the concavo-convex surface. It is considered to have a peel strength. Since the fine uneven layer is excellent in filling property of the thermoplastic resin and the peel strength is appropriate, the uneven shape formed on the thermoplastic resin is almost not partly missing, Good reproducibility. Also, if the peel strength is moderate, the optical sheet has a concave-convex shape that occurs when the shaping sheet is peeled off from the optical sheet, or the optical sheet is a plate that cannot be bent. Distortion of the entire sheet is prevented or reduced. In addition, when the resin composition for forming the fine uneven layer has a pencil hardness of 2B or more after curing, when the fine uneven layer is filled with a thermoplastic resin, it is thermally cured by deformation of the fine uneven shape or the like. It is considered that the generation of bubbles in the conductive resin is prevented, and this also improves the reproducibility of forming the fine uneven layer.
Furthermore, since the resin composition for forming the fine uneven layer is excellent in filling property to the mold used when producing the shaping sheet itself, and the peel strength from the mold becomes appropriate, the fine uneven layer By forming the fine concavo-convex layer using the forming resin composition, the shape reproducibility when producing the shaped sheet itself is excellent.

As the acrylate ionizing radiation curable resin, a resin that can be cured by ionizing radiation in which an acrylate prepolymer and / or a monomer having a radical polymerizable unsaturated bond in the molecule is appropriately mixed is used.
The ionizing radiation means electromagnetic waves or charged particles having energy that can be cured by polymerizing molecules. For example, all ultraviolet rays (UV-A, UV-B, UV-C), visible rays, gamma rays X-rays, electron beams, and the like are mentioned, but ultraviolet rays (UV) or electron beams (EB) are preferably used from the viewpoint of excellent heat resistance.
As the ionizing radiation curable resin, one kind may be used alone, or two or more kinds may be mixed and used.

  The acrylate prepolymer having a radically polymerizable unsaturated bond in the molecule is not particularly limited. For example, polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, melamine (meth) acrylate, A triazine (meth) acrylate etc. are mentioned. Among them, those having a benzene ring such as bisphenol A type epoxy acrylate and biphenyloxyethyl acrylate are preferable from the viewpoint of excellent heat resistance.

  The molecular weight of the prepolymer is not particularly limited, but is usually 250 to 100,000, and 500 to 10,000 is particularly preferable from the viewpoint of heat resistance.

  The acrylate monomer having a radically polymerizable unsaturated bond in the molecule is not particularly limited, and examples thereof include monofunctional monomers such as methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and phenoxyethyl (meth) acrylate. And diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta ( And polyfunctional monomers such as (meth) acrylate and dipentaerythritol hexa (meth) acrylate. Among them, those having a benzene ring such as bisphenol A type epoxy acrylate and biphenyloxyethyl acrylate are preferable from the viewpoint of excellent heat resistance.

As the acrylate ionizing radiation curable resin, these monomers or prepolymers are used alone, or two or more monomers are mixed, two or more prepolymers are mixed, or one monomer is used. A mixture of the above and one or more prepolymers can be used.
The acrylate ionizing radiation curable resin is not particularly limited, but an epoxy acrylate is preferable, and bisphenol A epoxy diacrylate is more preferable.

  The acrylate ionizing radiation curable resin is not particularly limited, but the monomer content is preferably 80 to 98% by weight, and particularly preferably 90 to 95% by weight. Thereby, it becomes easy to make pencil hardness (20g load) prescribed | regulated to JISK5600-5-4 of the said fine uneven | corrugated layer to be 2B or more.

  In the present invention, the acrylate ionizing radiation curable resin is preferably one having a pencil hardness (20 g load) as defined in JIS K5600-5-4 after curing of 2B or more, and HB or more. It is particularly preferable to use Thereby, it becomes easy to make the pencil hardness (20 g load) prescribed | regulated to JIS K5600-5-4 of the said fine uneven | corrugated layer into 2B or more, and the shaping reproducibility of the shaping sheet which concerns on this invention can be improved. it can.

  The acrylate ionizing radiation curable resin is not particularly limited, but a light transmissive resin is preferably used. Thereby, since a fine uneven | corrugated layer becomes what has excellent light transmittance, when producing a shaping sheet, mixing of a foreign material or a bubble can be visually inspected and quality control becomes easy. Moreover, when the fine uneven | corrugated layer which a shaping sheet has is a light transmittance and a base material is also a light transmittance, the quality control at the time of producing an optical sheet using the said shaping sheet becomes easy.

  The content of the acrylate ionizing radiation curable resin in the resin composition for forming a fine concavo-convex layer is not particularly limited, but is based on solid content (nonvolatile component) from the viewpoint of hardness and adhesion to a substrate. It is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more. In addition, since the said resin composition for fine uneven | corrugated layer formation also contains a phosphoric-ester type mold release agent as an essential component, content of the said acrylate type ionizing radiation-curable resin is less than 100 weight%.

The resin composition for forming a fine concavo-convex layer includes a phosphoric ester release agent.
Although it does not specifically limit as said phosphate ester mold release agent, For example, C4-C20 polyfluoroalkyl group containing phosphate ester, polyoxyethylene alkyl ether phosphoric acid and its salt, polyoxyethylene alkyl phenyl ether Examples thereof include phosphoric acid and its salt, and alkyl phosphoric acid and its salt.

  Although content of the said phosphate ester type release agent in the said resin composition for fine uneven | corrugated layer formation is not specifically limited, It is 0.01-1.00 weight% on solid content (nonvolatile component) basis. It is preferably 0.03 to 0.70% by weight, more preferably 0.05 to 0.50% by weight, still more preferably 0.10 to 0.25% by weight. When the content is less than the lower limit value, the releasability is inferior, and when the mold sheet is peeled from the optical sheet, deformation of the uneven shape of the optical sheet or distortion of the entire optical sheet is likely to occur, which exceeds the upper limit value. When the mold sheet is peeled off from the optical sheet, the mold sheet is peeled off from the substrate when the mold sheet is peeled off from the optical sheet. May end up.

When an ultraviolet curable resin is used as the acrylate ionizing radiation curable resin, the resin composition for forming a fine uneven layer may include a photopolymerization initiator. As such a photopolymerization initiator, for example, acetophenones, benzophenones, Michler benzoylbenzoate, α-amyloxime ester, thioxanthones, and the like can be used.
Moreover, the resin composition for forming a fine uneven layer may contain n-butylamine, triethylamine, tri-n-butylphosphine or the like as a photosensitizer.

The resin composition for forming a fine concavo-convex layer may contain various additives depending on the physical properties of the acrylate ionizing radiation curable resin after curing. Examples of such additives include a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, an adhesion improver, a leveling agent, a plasticizer, an antifoaming agent, a filler, and a solvent. .
The resin composition for forming a fine uneven layer may contain other additives, for example, an antioxidant, a slip agent, an antiblocking agent, a UVA absorber, a crystal nucleating agent and the like as necessary. .

  As the viscosity before curing of the resin composition for forming a fine concavo-convex layer, it can be used as long as it can form a fine concavo-convex layer having a desired shape when used in a method for producing a shaping sheet, which will be described later. Although not limited, it is usually within a range of 20 to 200,000 cps at 25 ° C., and particularly preferably within a range of 300 to 3,000 cps.

The fine concavo-convex layer has a pencil hardness (20 g load) as defined in JIS K5600-5-4 after curing of 2B or more, and particularly preferably HB or more. Thereby, it is considered that bubbles are less likely to occur when the thermoplastic resin is filled and cured in the fine uneven layer of the shaping sheet according to the present invention, and as a result, the fine uneven layer is excellent in shaping reproducibility. . If the pencil hardness of the fine concavo-convex layer is less than 2B, the fine concavo-convex layer may be deformed at the time of heat molding when laminating a thermoplastic resin melted on the fine concavo-convex layer, resulting in poor mold reproducibility. In addition, although the upper limit of the pencil hardness of the said fine uneven | corrugated layer is not specifically limited, It is desirable that it is 3H or less. This is because if the pencil hardness is higher than 3H, the possibility of damaging the molded product at the time of peeling increases.
The pencil hardness can be adjusted by the type and content of the resin contained in the resin composition for forming a fine uneven layer.

  Although the said fine uneven | corrugated layer is not specifically limited, From a viewpoint of quality control, it is preferable that a total light transmittance is 80% or more, and it is more preferable that it is 90% or more. The total light transmittance can be measured with a haze meter.

  The fine concavo-convex layer preferably has a heat resistant temperature measured according to JIS K7206 of 100 ° C. or higher, particularly preferably 120 ° C. or higher. This is because if the heat resistance temperature is less than 100 ° C., the fine uneven layer may be deformed or the like at the processing temperature during the production of the optical sheet.

The concavo-convex shape of the fine concavo-convex layer is not particularly limited, but in the present invention, the effect of the present invention can be achieved even when the concave portion having the concavo-convex shape reaches the deepest portion, that is, the concave tip is narrow and is not easily filled with the thermoplastic resin. Can be played. That is, the concavo-convex shape of the fine concavo-convex layer has a ratio (height / pitch) of height (projection height of the convex portion as shown by h in FIG. 1) and pitch (p in FIG. 1) to 1. / 5 or more and the concave / convex shape having a portion where the deepest part of the concave portion has a spire shape can be formed. Under more preferable conditions, the height / pitch can be 1/3 or more, and Under preferable conditions, the height / pitch can be ½ or more. In the present invention, the deepest reaching portion of the concave portion is a spire shape means that the concave and convex portion has a flat shape without a flat bottom surface, for example, in a vertical cross section of the concave and convex shape. The shape etc. with which a recessed part is V-shaped valley shape are mentioned.
Further, the upper limit of the height / pitch can be set to 5/1 even if a small estimate is made.

The pitch is not particularly limited and can be adjusted as appropriate. However, the moldable sheet according to the present invention has a complex concavo-convex shape, and the moldability reproducibility when a thermoplastic resin is laminated on the concavo-convex shape. The pitch can be accurately shaped even if it is 1000 nm or less, which is required for nanoimprint products, for example. Under more preferable conditions, it can be accurately shaped even if it is 150 nm or less required for a moth-eye type antireflection sheet. Can be typed. The pitch is usually 50 nm or more even in a moth-eye type antireflection sheet.
When using the shaping sheet which concerns on this invention for manufacture of a light-guide plate, the said pitch is although it does not specifically limit, It is preferable that it is 10-100 micrometers, and it is especially preferable that it is 20-60 micrometers. The pitch is usually 1000 nm or more in the case of a prism sheet.

  The concavo-convex shape of the fine concavo-convex layer is not particularly limited. For example, the groove-shaped unit concavo-convex structure obtained by inverting the side surface of the columnar shape is the same as the direction orthogonal to the extending direction (direction in which the ridge line runs). It can be made into the shape which arranged in multiple numbers on the surface, or the shape which reversed the moth-eye structure of nanometer order.

The columnar shape is not particularly limited, and examples thereof include a prismatic shape and a curved columnar shape.
As the groove-shaped unit concavo-convex structure in which the prismatic side surface portion is inverted, a groove-shaped unit prism in which the prismatic side surface portion such as a triangular prism (see FIG. 1), a trapezoidal quadrangular column, a pentagonal column, or the like is inverted. Strictly speaking, the structure is not a straight side, but a groove-like unit prism structure in which side faces of a substantially prismatic shape such as a substantially triangular prism shape that is a polygonal line or a curve consisting of two or more straight lines are inverted. It is done.
The groove-shaped unit concavo-convex structure in which the curved columnar side surface portion is inverted typically includes a groove-shaped unit lens structure in which the semicylindrical or semi-elliptical columnar side surface portion is inverted.
In the present invention, the terms “prism” and “lens” mean shape elements (optical elements) that can exert various optical actions (for example, reflection and refraction) on incident light. Terms such as “prism” and “lens” are not distinguished from each other as a shape element (optical element) based solely on the difference in designation.

  Further, in the present invention, the “moth eye structure” is a structure having a regular protrusion arrangement like a moth eye, and the protrusion shape includes a hemisphere, a half-spheroid shape of a spheroid, a conical shape and a quadrangular pyramid shape. And the like. The moth-eye structure in the nanometer order means a structure in which the protrusions are arranged at a pitch of several tens of nanometers to several hundreds of nanometers. The optical sheet having such a nanometer-order moth-eye structure is not particularly limited, but is mainly used as an antireflection sheet. In the present invention, an antireflection sheet having a moth-eye structure may be referred to as a “moth-eye type antireflection sheet”.

The thickness of the fine concavo-convex layer is not particularly limited, but from the viewpoint of handleability and cost, it is usually 10 to 300 μm in the case of a prism sheet, and usually 0.05 to 10 μm in the case of a moth-eye type antireflection sheet. is there.
In addition, in this invention, the thickness of a fine uneven | corrugated layer means the distance (t in FIG. 1) from the vertex of the highest convex part to the boundary with a base material.

C. The entire shaping sheet The total thickness of the shaping sheet according to the present invention is not particularly limited, but is preferably 50 to 550 μm and more preferably 100 to 200 μm from the viewpoints of handleability and cost. In the present invention, the total thickness of the shaping sheet is the sum of the thickness of the substrate and the thickness of the fine uneven layer.

  Although the total light transmittance of the shaping sheet which concerns on this invention is not specifically limited, It is preferable that it is 80% or more, and it is more preferable that it is 90% or more. The total light transmittance can be measured with a haze meter.

  As an application of the shaping sheet according to the present invention, in addition to shaping the uneven shape of the optical sheet, it can be laminated on the uneven surface of the optical sheet and used as a protective sheet. When using the shaping sheet concerning this invention as a protective sheet, it is preferable that the shape of the uneven surface of an optical sheet and the uneven shape of the said shaping sheet fit.

D. Method for Producing Molding Sheet The method for producing the shaping sheet according to the present invention is not particularly limited. For example, first, the fine concavo-convex layer is formed between the concavo-convex shape of the original for forming a shaped sheet and the substrate. The resin composition is filled and cured to form a fine concavo-convex layer in which the concavo-convex shape of the original plate for forming sheet is formed. Then, the method etc. which peel the laminated body which consists of the said fine uneven | corrugated layer and the said base material from the said original plate for shaping sheet formation, and obtain a shaping sheet etc. can be mentioned.
The method for forming the concave / convex shape of the original for forming a forming sheet into a fine concave / convex layer can be appropriately selected according to the type of the resin composition for forming the fine concave / convex layer, for example, a coating curing method (ionizing radiation curing) Law).

The concavo-convex shape of the forming sheet forming original plate is the same as the concavo-convex shape of the optical sheet. Such an original plate for forming a sheet is not particularly limited as long as it is not deformed and worn when repeatedly used, and may be made of metal or resin. Usually, metal is preferably used. This is because it is excellent in deformation resistance and wear resistance.
Moreover, the shape of the original plate for forming sheet is not particularly limited as long as a desired shape can be formed. For example, the shape may be a flat plate shape or a roll shape. However, it is preferable to use a roll-shaped mold (hereinafter sometimes referred to as “roll mold”) from the viewpoint of improving productivity.
In addition, as described above, the concavo-convex shape formed on the shaping sheet forming original plate is appropriately selected according to the shape of the desired shaping sheet forming original plate. May be formed so as to be orthogonal to the advancing direction of the shaping sheet forming original plate (see FIG. 2), or may be formed so as to be parallel. Especially, it is preferable that it is formed so that it may become parallel with the advancing direction of the original plate for shaping sheet formation. This is because when manufacturing by a method such as cutting with an NC lathe, the accuracy and processing speed can be excellent, and bubbles are difficult to enter during molding.
As a method for producing such a roll mold, a general method for producing an original master for molding can be used. Specifically, depending on a desired shape to be molded, a roll-shaped mold material is used. And a method of cutting grooves with an NC lathe.

  Among the method for producing a shaped sheet according to the present invention, a specific method by the coating and curing method includes, for example, a method as shown in FIG. That is, a roll mold 4 and a substrate 2 are prepared as a master for forming a forming sheet having an uneven shape obtained by inverting the uneven shape of the fine uneven layer of the forming sheet. The resin composition 6 for forming a fine uneven layer is extruded and filled between the materials 2 from the extruder 5, and ionizing radiation is applied from the surface side of the substrate 2 on which the resin composition 6 for forming the fine uneven layer is not laminated. By irradiating, the fine concavo-convex layer forming resin composition 6 is cured, whereby the fine concavo-convex layer 3 having the concavo-convex shape obtained by inverting the concavo-convex shape of the roll mold 4 is formed on the substrate 2. A mold sheet is obtained. In this example, the concavo-convex shape 4a in the roll mold 4 which is the original plate for forming the shaping sheet is, for convenience of explanation, the traveling direction (rotation direction) of the roll mold 4 and the ridge line of the concavo-convex shape 4a are orthogonal to each other. That is, the ridge line of the concavo-convex shape 3a of the fine concavo-convex layer 3 of the shaped sheet to be formed is orthogonal to the longitudinal direction of the shaped sheet, but is not particularly limited. For example, although not shown, the traveling direction (rotation direction) of the roll mold 4 and the ridge line of the concavo-convex shape 4a are parallel, that is, the ridge line of the concavo-convex shape 3a of the fine concavo-convex layer 3 and the longitudinal direction of the shaping sheet May be parallel to each other.

  The temperature at the time of ionizing radiation curing and the amount of ionizing radiation irradiation are not particularly limited as long as the fine uneven layer can be formed in the uneven shape fitted to the shaping sheet forming original plate. .

  In addition, in order to impart releasability to the fine uneven layer of the shaping sheet, EB treatment (electromagnetic field treatment) may be performed after forming the fine uneven layer on the substrate.

  Moreover, this process may apply | coat a primer layer beforehand on a base material from a viewpoint of the adhesive improvement of a base material and a fine uneven | corrugated layer. As a material for such a primer layer, an ionizing radiation curable resin or the like can be suitably used. Furthermore, an antistatic agent and a mold release agent can also be used as needed.

(Optical sheet manufacturing method)
Next, a method for producing an optical sheet using the shaping sheet according to the present invention will be described.
The method for producing an optical sheet according to the present invention comprises forming a resin layer by laminating a molten thermoplastic resin on the concavo-convex surface of the fine concavo-convex layer of the molding sheet according to the present invention, and applying a resin coating. A resin-coated molded sheet forming step of forming a mold sheet; and a molded sheet peeling step of separating the molded sheet from the resin-coated molded sheet to obtain an optical sheet.
According to the method for manufacturing an optical sheet according to the present invention, it is possible to produce a large product having a length of 2 m or more and a thin product having a thickness of 0.4 mm or less, which cannot be realized by conventional injection molding, and is also mass-productive. An optical sheet can be produced excellently and inexpensively.
In the manufacturing method according to the present invention, the type of the thermoplastic resin for forming the optical sheet is appropriately selected, and the thickness of the resin layer to be formed is changed, so that the obtained optical sheet has a plate shape. It can also be made windable.

  In FIG. 3, the schematic explaining an example of the manufacturing method of the optical sheet which concerns on this invention is shown. First, the above-described shaping sheet 1 according to the present invention is prepared (FIG. 3A), and a thermoplastic resin for forming an optical sheet is formed on the concavo-convex surface of the fine concavo-convex layer 3 of the shaping sheet 1. The resin layer 7 is laminated by melt extrusion to form a resin-coated shaping sheet 8 (FIG. 3B). Subsequently, the optical sheet 9 which consists of the resin layer 7 in which the uneven | corrugated shape of the fine uneven | corrugated layer 3 was shape | molded by peeling the shaping sheet 1 from the resin coating shaping sheet 8 can be obtained (FIG.3 (c)). ). Therefore, the uneven shape on the surface of the optical sheet obtained by the manufacturing method of the present invention is a shape obtained by inverting the uneven shape of the shaping sheet. The optical sheet obtained by the method of the present invention may be composed of only a resin layer formed by laminating a thermoplastic resin, and further laminated with other layers such as a protective sheet. Also good.

  The thermoplastic resin laminated on the uneven surface of the fine uneven layer of the shaping sheet is not particularly limited and is appropriately selected depending on the optical sheet to be manufactured. For example, acrylic resin, polyester resin, polycarbonate resin, polyethylene resin And polypropylene resin. Among them, acrylic resin and polycarbonate resin are preferable because of excellent heat resistance, small optical anisotropy, and high light transmittance. An acrylic resin is particularly preferable from the viewpoint of light transmission, and a polycarbonate resin is particularly preferable from the viewpoint of heat resistance.

Examples of the acrylic resin include a homopolymer of (meth) acrylic acid ester monomers, a copolymer of two or more different (meth) acrylic acid ester monomers, (meth) acrylic acid ester monomers and other vinyl monomers And a copolymer obtained by copolymerization of
The (meth) acrylic acid ester monomer is not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate.
Although it does not specifically limit as said other vinyl monomer, For example, styrene, ethylene, etc. are mentioned.
In addition, in the copolymer of the (meth) acrylic acid ester monomer and other vinyl monomers, the copolymer component preferably contains 50% by weight or more of the (meth) acrylic acid ester monomer, and is 80% by weight. It is especially preferable that it is contained above.
As the acrylic resin, a homopolymer or copolymer of (meth) acrylic acid ester monomer is preferable from the viewpoint of excellent light transmittance. Specifically, polymethyl methacrylate resin (PMMA) is particularly preferable. preferable. From the viewpoint of excellent heat resistance, a copolymer of (meth) acrylic acid ester monomer and styrene is preferable, specifically, a copolymer of polymethyl methacrylate resin (PMMA) and styrene is particularly preferable, and PMMA. More preferably, the ratio of styrene to styrene (PMMA: styrene) is 90:10 to 60:40.

  The polycarbonate resin is a polymer obtained by a phosgene method in which a dihydroxydiaryl compound and phosgene are reacted or a transesterification method in which a dihydroxydiaryl compound and a carbonic ester such as diphenyl carbonate are reacted. Examples thereof include polycarbonate resins produced from 2,2-bis (4-hydroxyphenyl) propane and bisphenol A, and among them, those obtained by polymerizing bisphenol A and carbonyl chloride by an interfacial polymerization method are preferable.

As the heating temperature when laminating the melted thermoplastic resin on the uneven surface of the fine uneven layer of the shaping sheet, if the thermoplastic resin can be laminated on the uneven shape of the shaping sheet, It is not specifically limited, It sets suitably according to the thermoplastic resin etc. which are used.
The shaped sheet according to the present invention is superior in heat insulation compared to a metal mold or the like, so that the thermoplastic resin is maintained at a temperature above the softening point, that is, in a state having flexibility, It becomes possible to make it press-fit to a shaping sheet with time. Therefore, a thermoplastic resin spreads to the detail of the uneven | corrugated shape of a shaping sheet, and a desired uneven | corrugated shape can be shape | molded. Thereafter, the thermoplastic resin can be cooled and cured to fix the shaped uneven shape.
The pressure at the time of pressure bonding is not particularly limited as long as the uneven shape of the shaping sheet can be shaped, and is appropriately adjusted according to the thermoplastic resin used.

  The resin-coated mold sheet formed by laminating a melted thermoplastic resin on the mold sheet according to the present invention is formed by coating a resin layer serving as an optical sheet on the uneven surface of the mold sheet. The uneven shape of the sheet and the uneven shape of the resin layer are arranged so as to fit each other. Therefore, since the adhesiveness is high and the storage property is excellent, the possibility that dirt such as scratches and dust adheres to the uneven surface of the optical sheet in the manufacturing process of the optical sheet can be extremely reduced. Even when the optical sheet is stored, it is possible to extremely reduce the possibility that dirt such as scratches and dust adheres to the uneven surface of the optical sheet by storing it in the state of the resin-coated shaped sheet.

After forming the resin-coated molded sheet, the optical sheet is obtained by peeling the molded sheet from the resin-coated molded sheet.
The peel strength (in accordance with JIS K6854) when peeling the shaped sheet from the resin-coated shaped sheet is preferably 0.01 N or more and less than 1 N in the measurement of 25 mm width and 90-degree peeling. When the peel strength is less than the lower limit value, the molded sheet and the resin layer do not adhere to each other, and the obtained optical sheet may not be accurately molded. When the upper limit value is exceeded, the resin-coated molded sheet This is because a large force is required to peel off the shaping sheet, so that the uneven shape of the obtained optical sheet may be deformed or the entire optical sheet may be distorted. By making the peel strength within the above range, when the mold sheet is peeled from the optical sheet, the uneven shape of the optical sheet is not deformed or the entire optical sheet is not distorted. Even if the concavo-convex shape is a complicated shape, the effect of the present invention that the optical sheet can be accurately shaped is further enhanced. As a result, the optical sheet manufacturing method according to the present invention has a plate-like shape such as a light guide plate and should not be distorted in order to guide light, or a moth-eye structure of nanometer order. This is particularly useful in the production of optical sheets having complicated and uneven shapes. In order to further enhance the effect of the present invention, the peel strength is particularly preferably 0.05 to 0.2 N / 25 mm (measurement of 90 degree peel).

In the manufacturing method of the optical sheet which concerns on this invention, the process of cut | judging a resin coating shaping sheet or an optical sheet to a desired size may be included in the process. For example, after cutting the resin-coated molded sheet to a desired size, the molded sheet may be peeled from the resin-coated molded sheet, or the optical sheet obtained by peeling the molded sheet from the resin-coated molded sheet The sheet may be cut into a desired size.
Examples of the cutting method include router, laser, press, shearing, dicing and the like.

  When producing a light guide plate as an optical sheet, the light incident end surface on the side where the light source of the light guide plate is disposed is mirror-finished by a mirror polishing apparatus that rotates and polishes a blade or a method that thermally transfers a mold polished to a mirror surface. It may be polished.

  Moreover, in the manufacturing method of the optical sheet which concerns on this invention, in order to protect the surface (back surface) without an uneven | corrugated shape of an optical sheet from a damage | wound, dirt, etc., a back surface side protective film is bonded to the back surface side of an optical sheet. Alternatively, after peeling off the molding sheet from the resin-coated molding sheet, a surface-side protective film may be bonded onto the surface (surface) having the irregular shape of the optical sheet. As said back surface side protective film and surface side protective film, the general thing used as a protective film of the conventional optical sheet can be used, for example.

Examples of the plate-like optical sheet obtained by the production method according to the present invention include a light guide plate. Although it does not specifically limit as a light-guide plate obtained by the manufacturing method which concerns on this invention, For example, one or more of the light emission surface, the back surface facing the said light emission surface, and the side surface between the said light emission surface and the said back surface And a unit prism formed on the light exit surface and linearly formed along the light guide direction on the same surface in a direction perpendicular to the light guide direction. One having a plurality of light-emitting surface optical element portions arranged therein is mentioned.
The light guide plate is inferior in the function of guiding light when the body portion is distorted, but in the manufacturing method of the present invention, the peeling strength when peeling the molding sheet from the resin-coated molding sheet is appropriate. Further, the main body portion of the light guide plate is hardly distorted and has an excellent function of guiding light.
The concavo-convex shape of the light exit surface optical element portion can be shaped by the shaping sheet according to the present invention. The unit prism of the light exit surface optical element portion is not particularly limited, but preferably has a triangular prism shape or a substantially triangular prism shape. Since the manufacturing method of the present invention is a method having excellent shaping reproducibility, even if the light-emitting surface optical element portion has a complicated uneven shape, it can be shaped accurately.
The back surface may be a flat surface or a surface having a shallow concavo-convex shape with a height of 10 μm or less, or a unit formed linearly so as to be orthogonal to the unit prism of the light exit surface optical element portion. It can also be a surface having a back optical element portion in which a plurality of prisms are arranged on the same surface. The shape of the unit prism of the back surface optical element portion may be the same as or different from the shape of the unit prism of the light exit surface optical element portion. As a method of forming the back surface optical element portion, for example, a method of forming a desired uneven shape on the back surface at the time of forming the uneven shape of the light exit surface using the shaping sheet according to the present invention may be used. A general forming method used when shaping the optical element portion of a conventionally known light guide plate may be used.

Although the thickness of the light-guide plate obtained by the manufacturing method which concerns on this invention is not specifically limited, Usually, it is 0.1 mm-10.0 mm, It is preferable that it is 0.2 mm-4 mm especially, It is 0.4 mm-2 mm. It is particularly preferred.
The light guide plate obtained by the manufacturing method according to the present invention is not particularly limited, but usually has a uniform thickness. The thickness of the light guide plate means the distance from the apex of the highest convex part of the concavo-convex shape of the light exit surface to the back surface, and when the concavo-convex shape is also formed on the back surface, the uneven surface of the light exit surface is the highest It means the distance from the apex of the convex part to the apex of the convex part having the highest uneven shape on the back surface.

  The rollable optical sheet obtained by the production method according to the present invention is not particularly limited, and examples thereof include a prism sheet, a lens sheet, and an antireflection sheet. The optical sheet that can be wound is not particularly limited, but usually has a concavo-convex shape formed by the shaping sheet according to the present invention on the front surface side, and the back surface is a flat surface or a shallow height of 10 μm or less. It is a surface having an uneven shape. The uneven shape on the surface side is not particularly limited as long as the uneven shape of the shaping sheet according to the present invention is inverted, but particularly those having the effect of the present invention being particularly effective are particularly complex uneven. This is a case of a moth-eye structure of nanometer order which is a shape. The optical sheet that can be wound is less likely to cause a problem that the main body is distorted like the light guide plate, but is manufactured by the manufacturing method of the present invention when the uneven surface shape is complicated. Thereby, the said uneven | corrugated shape can be shape | molded correctly.

The thickness of the rollable optical sheet obtained by the production method according to the present invention is not particularly limited, but is usually 0.025 mm to 1.0 mm, and preferably 0.05 mm to 0.5 mm.
The rollable optical sheet is not particularly limited, but usually has a uniform thickness, and the thickness is from the apex of the highest convex part of the concavo-convex shape on the front side to the back side (back side). In the case where a concavo-convex shape is also formed, it means the distance to the apex of the highest convex portion of the concavo-convex shape.

  FIG. 4 shows a schematic diagram of an example of an apparatus used in the method for producing an optical sheet according to the present invention. In the optical sheet manufacturing apparatus 100 shown in FIG. 4, the shaping sheet 10 is disposed between the rolls 11a and 11b, and the molten thermoplastic resin 13 is extruded and heated from the extruder 12 to a temperature equal to or higher than the softening point. The rolls 11a and 11b are gradually pressed onto the uneven shape of the shaping sheet 10. Then, it cools with the roll 11c (cooling roll), and the resin coating shaping sheet 14 which the resin layer which consists of the thermoplastic resin 13 coat | covered the shaping sheet 10 is formed. Next, the back surface protective film 15 is laminated on the resin layer side surface (the back surface of the optical sheet) of the resin coating shaped sheet 14 and cut by the cutting machine 17. Although not shown, the optical sheet can be obtained by peeling the shaping sheet thereafter.

FIG. 5 shows a schematic diagram of another example of an apparatus used in the method for producing an optical sheet according to the present invention. In the optical sheet manufacturing apparatus 101 shown in FIG. 5, after forming the resin-coated molding sheet 14 in the same manner as the optical sheet manufacturing apparatus 100 shown in FIG. 4, the molding sheet 10 is peeled from the resin-coated molding sheet 14, Subsequently, the back surface protective film 15 is laminated on the surface without the uneven shape of the resin layer 13 ′ having the uneven shape (the back surface of the optical sheet), and the surface protective film 16 is formed on the surface with the uneven shape (the surface of the optical sheet). Are laminated and cut by a cutting machine 17 to obtain an optical sheet.
In addition, as shown in FIG.4 and FIG.5, the shaping sheet which concerns on this invention is not limited to using it in a roll shape, A flat plate-shaped thing can also be used.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Example 1
1. Preparation of prism-type shaping sheet Grooves such that the cross-sectional shape in the axial direction on the circumference of a roll mold plated with copper on the surface is a triangular shape with apex angle 90 °, pitch 50 μm, height 25 μm, diamond bite Was cut with an NC lathe to obtain an original plate of a prism type shaping sheet.
Phosphate-based mold release agent (Daihachi Chemical Industry Co., Ltd.) so that it becomes 0.05 wt% of the total amount of UV curable acrylate resin (epoxy acrylate 1) blended with the following ingredients in the above-mentioned master for sheet From the back side of the PET substrate while filling the resin composition for forming a fine uneven layer to which AP-10) was added and making contact with a 125 μm thick PET substrate as a support substrate for forming a shaped sheet. UV irradiation was performed using a lamp (manufactured by Fusion, H bulb). The resin composition for forming a fine concavo-convex layer is cured in a mold by adjusting the cumulative amount of UV light to be 500 mJ, and the cured resin composition for forming a fine concavo-convex layer (fine concavo-convex layer) and a PET substrate Were peeled from the original plate for shaping sheet to obtain a prism type shaping sheet having a thickness of 153 μm.
When the pencil hardness (20 g load) prescribed | regulated to JISK5600-5-4 was measured about the fine uneven | corrugated layer of the obtained prism type shaping sheet, it was 2B.

<Epoxy acrylate 1>
Bisphenol A epoxy acrylate oligomer component: 16 parts by weight Phenoxyethyl acrylate monofunctional monomer component: 32 parts by weight Bisphenol A diacrylate polyfunctional monomer component: 52 parts by weight Photoinitiator (1-hydroxycyclohexyl phenyl ketone: 3 parts by weight

2. Preparation of laminate (resin coated molding sheet) of molding sheet and plate-shaped optical sheet Next, a pellet-shaped thermoplastic acrylic resin (Acrypet VH6 manufactured by Mitsubishi Rayon Co., Ltd.) is used as a resin for forming a plate-shaped optical sheet. From the hopper to the extruder, the shaping sheet is passed between the first roll and the second roll installed under the die of the extruder, and the thermoplastic acrylic resin is extruded from the die to the extrusion temperature of 200 ° C. between the rolls. The material was extruded at an extrusion speed of 3 m / min and rolled between rolls together with the shaping sheet. Then, it cooled with the 3rd roll and shape | molded in the flat plate shape, and obtained the laminated body by which the 0.8 mm-thick optical sheet was arrange | positioned on the shaping sheet. Next, the laminate was cut into a predetermined size by laser cutting to produce a laminate of the shaping sheet and the plate-like optical sheet.

(Examples 2 to 5)
Lamination of the shaping sheet and the plate-like optical sheet in the same manner as in Example 1 except that the content of the phosphate ester-based release agent in the fine uneven layer forming resin composition was changed as shown in Table 1. Got the body.

(Example 6)
1. Fabrication of moth-eye mold forming sheet An aluminum roll mold surface is anodized to form a so-called moth-eye structure of fine concavo-convex shape of a cylindrical or conical shape having an average pitch of about 100 nm and a height of about 200 nm, or an intermediate shape thereof. A roll mold having a moth-eye structure densely arranged at random on the same surface was prepared, and used as a master plate for a moth-eye mold forming sheet.
Fine irregularities obtained by adding a phosphoric ester-based mold release agent (manufactured by Daihachi Chemical Industry Co., Ltd., AP-10) to the epoxy acrylate 1 so as to be 0.05% by weight of the epoxy resin acrylate plate. A UV lamp (H bulb manufactured by Fusion) is used from the back side of the PET substrate while filling the layer forming resin composition and contacting the PET substrate having a thickness of 125 μm as the support substrate for forming the shaped sheet. UV irradiation. The resin composition for forming a fine concavo-convex layer is cured in a mold by adjusting the cumulative amount of UV light to be 500 mJ, and the cured resin composition for forming a fine concavo-convex layer (fine concavo-convex layer) and a PET substrate Were peeled from the original plate for shaping sheet to obtain a moth-eye shaping sheet having a thickness of 128 μm.
When the pencil hardness (20 g load) prescribed | regulated to JISK5600-5-4 was measured about the fine uneven | corrugated layer of the obtained moth-eye type shaping sheet, it was 2B.

2. Production of laminate (resin-coated shaped sheet) of shaped sheet and plate-shaped optical sheet Example 1 except that the moth-eye shaped shaped sheet obtained above was used instead of the prism shaped shaped sheet Similarly, a laminate of a shaping sheet and a plate-like optical sheet was produced.

(Examples 7 to 10)
Lamination of the shaping sheet and the plate-like optical sheet in the same manner as in Example 6 except that the content of the phosphate ester-based release agent in the fine uneven layer forming resin composition was changed as shown in Table 1. Got the body.

(Comparative Example 1)
A laminate of a shaping sheet and a plate-like optical sheet in the same manner as in Example 1 except that the epoxy acrylate 2 containing the following components was used as the UV curable acrylate resin, without using the epoxy acrylate 1. Got.

<Epoxy acrylate 2>
Phenoxyethyl acrylate monofunctional monomer component: 55 parts by weight Bisphenol A diacrylate polyfunctional monomer component: 42 parts by weight Photoinitiator (1-hydroxycyclohexyl phenyl ketone: 3 parts by weight

(Comparative Example 2)
A laminate of a shaping sheet and a plate-like optical sheet was obtained in the same manner as in Example 6 except that the epoxy acrylate 2 was used instead of the epoxy acrylate 1 as the UV curable resin.

(Evaluation of mold reproducibility)
For each of the above examples and comparative examples, the shaping sheet was peeled from the laminate of the shaping sheet and the plate-like optical sheet, and the fine uneven shape of the obtained optical sheet was measured with an electron microscope (manufactured by JEOL Ltd.). JSM-5800LV). In the case of an optical sheet obtained by using a prism type shaping sheet, the observation is made in a range of 100 μm × 100 μm, and in the case of an optical sheet obtained by using a moth-eye type shaping sheet, the observation is made in a range of 5 μm × 5 μm. did. The fine irregular shape of the shaped sheet after molding is also observed in advance with an electron microscope (JSM-5800LV, manufactured by JEOL Ltd.), and the optical sheet is finer than the fine irregular shape of the molded sheet after molding. Molding reproducibility is indicated by ○ indicating that the deformation is not observed on the uneven shape, △ indicating that the deformation is partially observed on the protrusion portion of the fine uneven shape, and × indicating that the deformation is recognized on the entire surface. evaluated. The evaluation results are shown in Table 1.
Moreover, about the optical sheet obtained by each said Example and each comparative example, the defect which can be observed visually is shown in Table 1 as "the defect of a molded article."

(Measurement of peel strength)
The laminate of the shaping sheet and the plate-like optical sheet obtained in each of the above examples and comparative examples was cut to a width of 25 mm, and a digital force gauge manufactured by Imada Co., Ltd. and a slide table for 90-degree peeling were used. The 25 mm width sample was fixed to the table with an adhesive tape, and the others were measured for peel strength between the optical sheet and the shaping sheet by a method based on JIS K6854. The measurement results are shown in Table 1.

As can be seen from Table 1, in Examples 1 to 10, since the shaping sheet according to the present invention was used, the obtained optical sheet was excellent in shaping reproducibility, the deformation of the uneven shape of the optical sheet and the entire optical sheet There was almost no distortion. In addition, since the optical sheet obtained in Examples 4 and 9 had a relatively high peel strength when the shaping sheet and the optical sheet were peeled off, a slight warpage was observed as compared with other examples. In addition, the optical sheets obtained in Examples 5 and 10 have relatively small adhesion between the shaping sheet and the optical sheet, the peel strength cannot be measured, and the obtained optical sheet is observed visually. Although there were some portions where the fine uneven shape was not shaped (indicated as “partial molding failure” in Table 1), the portion where the fine uneven shape of the optical sheet was shaped was observed with an electron microscope. Then, deformation of the fine uneven shape was not recognized, and the mold reproducibility was good. In addition, in the optical sheet obtained in Example 1, the deformation of the fine unevenness was partially recognized by observation with an electron microscope, and in the optical sheets obtained in Examples 3, 7 and 8, visually. Although some bubbles were observed, all were within the practical range.
On the other hand, in the optical sheet obtained in Comparative Example 1, many bubbles were visually observed, and when the fine uneven shape was observed with an electron microscope, deformation of the fine uneven shape was observed on the entire surface. This is considered to be because the fine uneven layer of the shaping sheet used in Comparative Example 1 was too soft with a pencil hardness of 3B.
In addition, the optical sheet obtained in Comparative Example 2 was observed with the naked eye, the fine uneven shape appeared to be formed uniformly, and no other defects were observed, but the fine uneven shape was When observed with an electron microscope, deformation was observed on the entire surface compared to the shaped sheet. This is considered to be because the fine uneven layer of the shaping sheet used in Comparative Example 2 was too soft with a pencil hardness of 3B.

DESCRIPTION OF SYMBOLS 1 Molding sheet 2 Base material 3 Fine uneven | corrugated layer 4 Roll die 5 Extruder 6 Resin composition for fine uneven | corrugated layer formation 7 Resin layer 8 Resin coating shaped sheet 9 Optical sheet 10 Molded sheets 11a, 11b, 11c, 11d Roll 12 Extruder 13 Thermoplastic resin 14 Resin-coated shaping sheet 15 Back surface protective film 16 Surface protective film 17 Cutting machine 100 Optical sheet manufacturing apparatus 101 Optical sheet manufacturing apparatus

Claims (10)

A shaped sheet in which a fine uneven layer is laminated on a substrate,
The fine concavo-convex layer is made of a cured product of a resin composition for forming a fine concavo-convex layer containing at least an acrylate ionizing radiation curable resin and a phosphate ester-based release agent, and is JIS K5600-5-4 after curing. The shaped sheet is characterized in that the pencil hardness (20 g load) specified in 1 is 2B or more.   The resin composition for forming a fine uneven layer contains 80 wt% or more of the acrylate ionizing radiation curable resin and 0.03 to 0.70 wt% of the phosphoric ester release agent, and the acrylate. The shaping sheet | seat of Claim 1 whose monomer content in the type | system | group ionizing radiation-curable resin is 80 to 98 weight%.   The concavo-convex shape of the fine concavo-convex layer has a portion in which the ratio of height to pitch (height / pitch) is 1/5 or more and the deepest reaching portion of the concave portion has a spire shape. Molding sheet.   The concavo-convex shape of the fine concavo-convex layer is a shape formed by arranging a plurality of groove-like unit concavo-convex structures in which columnar side surfaces are inverted on the same plane in a direction orthogonal to the extending direction, or a moth-eye of nanometer order The shaping sheet according to any one of claims 1 to 3, which has a shape having an inverted structure.   The shaped sheet according to any one of claims 1 to 4, wherein the base material and the fine uneven layer are formed of a light transmissive material.   A resin coating composition comprising a resin layer formed by laminating a melted thermoplastic resin on the concavo-convex surface of the fine concavo-convex layer of the molding sheet according to any one of claims 1 to 5. Mold sheet.   The peeling strength (based on JIS K6854) when peeling the said shaping | molding sheet and the said resin layer is 0.01 N or more and less than 1N by the measurement of 25 mm width and 90 degree | times peeling. Resin-coated shaped sheet. A resin layer is formed by laminating a molten thermoplastic resin on the concavo-convex surface of the fine concavo-convex layer of the molding sheet according to any one of claims 1 to 5, thereby forming a resin-coated molding sheet. Forming a resin-coated molded sheet; and
A molding sheet peeling step, which obtains an optical sheet by peeling the molding sheet from the resin-coated molding sheet,
Peeling strength (based on JIS K6854) when peeling the shaping sheet from the resin-coated shaping sheet is 0.01 N or more and less than 1 N in a measurement of 25 mm width and 90-degree peeling, Manufacturing method of optical sheet.   The method for producing an optical sheet according to claim 8, wherein the optical sheet is a light guide plate.   The method for producing an optical sheet according to claim 8, wherein the uneven shape formed on the surface of the optical sheet has a moth-eye structure.

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