JPH07233227A - Ionizing radiation curable resin composition for optical sheet, optical sheet and method for producing the same - Google Patents

Abstract

(57) [Summary] [Structure] An epoxy acrylate (a) having a cyclic structure and having two or more acrylate groups, a monofunctional acrylate (b) having a cyclic structure, and light added as necessary. It is composed of an initiator (c), has an acrylate functional group of 0.2 to 5.0 mmol / g, a viscosity at 25 ° C. of 1000 to 12000 cps, and a curing shrinkage ratio of 5.5% or less. Ionizing radiation curable resin composition for optical sheet, optical sheet using the ionizing radiation curable resin composition, and method for producing the optical sheet. [Effects] The present invention is useful for Fresnel lenses, lenticular lenses, back reflection lenses, etc., has a high surface hardness, does not have the problem of deformation during curing and deterioration of weather resistance, and has a short curing time and excellent productivity, An ionizing radiation curable resin composition for an optical sheet having a fine structure on the surface, an optical sheet, and a method for producing the same can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sheet having a fine structure on the surface of a Fresnel lens, a lenticular lens, a back reflection lens, a hologram or the like used in a liquid crystal display, a video projector or the like, and a resin composition for the optical sheet. And a method for manufacturing the optical sheet.

[0002]

2. Description of the Related Art In recent years, due to the rapid development of liquid crystal displays, it has become possible to use television monitors, video monitors and computer displays outdoors and in vehicles, and for backlights used in these applications. Use as an optical sheet for light diffusing plates, light collecting plates, lenticular lenses for projection television screens, Frennel lenses, etc. under high temperature, low temperature conditions, or high humidity, low humidity conditions not previously considered. The urgent development of an optical sheet that can withstand the above requirements is required.

Conventionally, an optical sheet has been disclosed in US Pat.
It is generally manufactured by injection molding or hot press molding of a thermoplastic resin disclosed in US Pat. No. 98, US Pat. No. 3,565,978, or the like. However, these manufacturing methods have problems that a long time is required for heating and cooling during manufacturing, productivity is low, and durability of the manufactured optical sheet is not sufficient. .

In recent years, there has been proposed a method for producing a replica of a lens master by interposing a reactive resin between the lens master and the transparent film and curing the reactive resin by heat or ultraviolet rays. . US Patent 252486
Japanese Patent Publication No. 2 describes a method of producing an optical component by photopolymerization of a monomer such as (meth) acrylic acid or methylmethacrylate, or a partially polymerized composition thereof.

Further, in US Pat. No. 3,689,346 and US Pat. No. 3,935,359, a crosslinkable resin composition such as a partially polymerized acrylic ester is injected into a lens matrix to generate active energy rays and heat. Describes a method of continuously producing an optical sheet by a method of solidifying.

In Japanese Patent Laid-Open No. 48-21546, a solventless photocurable resin is sandwiched between transparent sandwiching members, exposed from a transparent portion to cure the exposed portion, and the sandwiching member is contacted. Disclosed is a method for manufacturing an optical element, which comprises obtaining a photocurable resin molded body having a shape corresponding to a surface.

Further, US Pat. No. 4,376,800 describes a method of producing an optical article by ultraviolet curing a composition comprising an acrylic monomer and urethane acrylate. However, such a method causes deterioration of the work environment due to the use of a monomer having strong skin irritation and toxicity,
It took time until the reaction was completed, and it had a drawback of being inferior in productivity. Further, there are problems that mechanical properties are poor and that the film is curled or otherwise deformed due to shrinkage during curing.

In Japanese Patent Publication No. 62-51725, a radiation die-polymerizable resin containing a saturated hydrocarbon or a phenyl group is deposited on a metal die (master die) having an information track, and then the polymerizable resin. A substrate on the surface opposite to the die, or after depositing the polymerizable resin layer on the substrate in advance, depositing a polymerizable molding resin layer having the substrate on the die, Discloses a method of replicating a plastic information carrier such as a CD or LD by photo-curing a polymerizable molding resin and then removing the polymerizable molding resin layer and the substrate bonded thereto from the die.

Further, in US Pat. No. 4,576,850 and Japanese Patent Publication No. 4-5681, a mixture of compounds called a so-called soft segment and a hard segment is crosslinked and cured by ultraviolet irradiation to improve thermal dimensional stability. A method of improving mechanical properties is disclosed. However, these methods still have the problems that the curing time is long, the surface hardness of the resulting cured product is reduced by the introduction of the soft segment, the optical sheet is deformed during curing, and the weather resistance is reduced.

Further, an optical sheet produced by bringing a conventional ultraviolet curable layer and a resin transparent base material into close contact with each other has excellent mechanical strength as an optical sheet, but there is a problem in the adhesiveness at the contact interface. Problems remained in terms of long-term adhesion and durability.

[0011]

The problem to be solved by the present invention is that the surface hardness of the optical sheet is high, there is no problem of deformation of the sheet at the time of curing and deterioration of weather resistance, and the curing time is short, and the production is improved. An ionizing radiation curable resin composition for an optical sheet having excellent properties, an optical sheet, and a method for producing the same.

[0012]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an ionizing radiation curable resin having a fine structure using a specific ionizing radiation curable resin composition. An optical sheet comprising three layers of a composition layer (A), an adhesive layer (B) and a sheet-like transparent resin layer (C) has excellent durability while maintaining the hardness of the surface of the cured product, And, a novel ionizing radiation curable resin composition having extremely small deformation such as curl during curing as an optical sheet, and having a thin film thickness, capable of designing a fine pattern, having a high curing speed,
The present invention has been completed by finding an optical sheet using the resin composition and a method for producing the same.

That is, the present invention has an epoxy acrylate (a) having a cyclic structure and having two or more acrylate groups, and a monofunctional acrylate (b) having a cyclic structure.
And a photoinitiator (c) added as necessary,
The acrylate functional group is 0.2 to 5.0 mmol / g,
An ionizing radiation curable resin composition for an optical sheet, which has a viscosity at 25 ° C. of 1000 to 12000 cps and a curing shrinkage calculated by Formula 1 of 5.5% or less. Curing shrinkage (%) = (DS-DL) / DS × 100 (Equation 1) (where DL represents the specific gravity of the composition before curing, and DS represents the specific gravity after curing).

The present invention also provides an epoxy acrylate (a) having a cyclic structure and having two or more acrylate groups.
Is an epoxy acrylate having a structure of bisphenol A and / or hydrogenated bisphenol A, which is an ionizing radiation curable resin composition for an optical sheet, which further has a cyclic structure and has two or more acrylate groups. The epoxy acrylate (a) having the formula (1) is an epoxy acrylate having a structure of partially halogen-substituted bisphenol A and / or hydrogenated bisphenol A, including a resin composition for an optical sheet.

The monofunctional acrylate (b) having a cyclic structure of the resin composition for an optical sheet of the present invention is particularly isobornyl (meth) acrylate, glycidyl cyclocarbonate (meth) acrylate, or tetrahydrofurfuryl (meth) acrylate. Or 2-hydroxy-3-phenoxy-propyl (meth) acrylate.

The present invention also provides an ionizing radiation-curable resin composition layer (A) having a fine structure, which is composed of the above-mentioned ionizing radiation-curable resin composition for optical sheets, and an adhesive layer (B) provided as necessary. And the sheet-shaped transparent resin layer (C).

In the optical sheet of the present invention, the adhesive layer (B) comprises a cellulose resin (b1) and a polyisocyanate (b2), and the adhesive layer (B) has a molecular weight of 3000. 30,000 polyester resin (b3)
And a polyisocyanate (b2), and the adhesive layer (B) comprises a polyester resin (b3) having a molecular weight of 3,000 to 30,000, an epoxy acrylate having a cyclic structure, and a photoinitiator, and the epoxy resin The optical sheet has an acrylate content of 10% to 60%.

The optical sheet of the present invention is an optical sheet characterized in that the sheet-shaped transparent resin layer (C) is a polyester or a polycarbonate resin. An optical sheet comprising a layer (A) having a fine structure made of an ionizing radiation-curable resin composition, an adhesive layer (B), and a sheet-like transparent resin layer (C) made of polyester or polycarbonate resin. It is

Further, the optical sheet of the present invention comprises a layer (A) having a fine structure comprising the above-mentioned ionizing radiation-curable resin composition for an optical sheet, a cellulose resin (b1) and a polyisocyanate (b2). An optical sheet comprising an adhesive layer (B) composed of (1) and a sheet-shaped transparent resin layer (C) composed of polyester or polycarbonate resin,

Similarly, a layer (A) having a fine structure composed of the above-mentioned ionizing radiation curable resin composition for an optical sheet.
An adhesive layer (B) comprising a polyester resin (b3) having a molecular weight of 3000 to 30,000 and a polyisocyanate (b2), and a sheet-like transparent resin layer (C) comprising a polyester or polycarbonate resin. Composed optical sheet
And

A layer (A) having a fine structure composed of the above-mentioned ionizing radiation curable resin composition for an optical sheet, a polyester resin having a molecular weight of 3,000 to 30,000, an epoxy acrylate having a cyclic structure, and a photoinitiator. And the content of epoxy acrylate is 10% to 60%
An optical sheet comprising an adhesive layer (B) made of the resin composition and a sheet-like transparent resin layer (C) made of polyester or polycarbonate resin.

Further, the present invention comprises a step of rotating a roll intaglio on which a mold having a desired fine concavo-convex shape is formed, and at least a recess of the roll intaglio is filled with an ionizing radiation curable resin liquid; A contact step of bringing a transparent resin sheet base material, which travels in synchronization with the rotation direction of the roll intaglio, into contact with the ionizing radiation-curable resin liquid filled in the roll intaglio;

In the contacting step, while the sheet base material is in contact with the roll intaglio plate, the ionizing radiation curable resin liquid between the roll intaglio plate and the sheet base material is cured by irradiating it with ionizing radiation. A step of adhering the ionizing radiation curable resin liquid that is cured in the curing step and the sheet base material;

A curing step of peeling the sheet base material from the roll intaglio and the cured product of the ionizing radiation curable resin liquid adhered in the adhering step; and the ionizing radiation curable resin liquid is the above-mentioned optical sheet. Is an ionizing radiation-curable resin composition for use in an optical sheet.

The present invention also includes a step of coating an adhesive layer on a transparent resin sheet base material; rotating a roll intaglio on which a mold having a desired fine concavo-convex shape is rotated, and curing at least recesses of the roll intaglio by ionizing radiation. A filling step of filling a mold resin liquid; a transparent resin sheet substrate that travels in synchronization with the rotating direction of the roll intaglio resin resin liquid filled in the roll intaglio plate in the filling step. A contact step of contacting the adhesive layer side;

In the contacting step, while the sheet base material is in contact with the roll intaglio plate, the ionizing radiation-curable resin liquid between the roll intaglio plate and the sheet base material is cured by irradiating it with ionizing radiation. A step of adhering the ionizing radiation curable resin liquid that is cured in the curing step and the sheet base material through an adhesive layer;

The ionizing radiation-curable resin liquid is used for the above-mentioned optical sheet, which includes a peeling step of peeling the cured product of the ionizing radiation-curable resin liquid adhered in the contacting process and the sheet base material from the roll intaglio plate. It includes a method for producing an optical sheet, which is an ionizing radiation curable resin composition.

The present invention also relates to the adhesive layer (B) of the optical sheet.
The absorption wavelength of the photoinitiator contained therein is 400 nm or less, and the absorption wavelength of the photoinitiator contained in the ionizing radiation curable resin composition layer (A) is 450 nm or less. It includes a sheet manufacturing method.

The present invention will be described in detail below. The present invention has a high curing rate, a specific ionizing radiation curable resin composition for optical sheets, and an ionizing radiation curable resin composition layer (A) having a fine structure using the ionizing radiation curable resin composition, It is an optical sheet comprising three layers of an adhesive layer (B) provided as necessary and a sheet-shaped transparent resin layer (C), and a method for producing the same. The present invention provides an optical sheet that has excellent durability while maintaining the hardness of the surface of the optical sheet, has very little deformation such as curling during curing, has a thin film thickness, and can be designed for a fine pattern. .

The hardness of the ionizing radiation curable resin is influenced by the rigidity of the resin skeleton, the crosslink density, the reaction rate and the like. If a soft component is introduced as the resin skeleton, the hardness becomes low at the same crosslink density. However, if the crosslinking density is increased to compensate for the hardness, the curing shrinkage becomes large when the ionizing radiation curable resin is cured, and the optical sheet is likely to be deformed.

In order to reduce the deformation of the optical sheet, that is, the curl of the sheet, one method of reducing the crosslinking density of the ionizing radiation-curable resin composition is to add a UV-reactive oligomer having a large molecular weight to the composition. Also, the addition of thermoplastic polymers has been investigated.

However, in order to reduce the cross-linking density of the ionizing radiation curable resin composition, if a UV-reactive oligomer having a large molecular weight or a thermoplastic polymer is used, the viscosity of the resin composition before curing becomes extremely high. .

However, the viscosity of the resin composition used is 10 at 25 ° C. for uniform coating of the ionizing radiation-curable resin composition on the mother mold and for replication of the mother mold having a fine structure.
It is desirable to be in the range of 00 cps to 12000 cps, and if it exceeds 12000 cps, or conversely 1000 cps or less, it becomes impossible to sufficiently mold the resin composition to the fine portion of the mother mold, and continuous coating is difficult. Becomes

To further improve this, if a solvent or the like is added to reduce the viscosity of the composition, a step of volatilizing these solvents is required, and a fine matrix is formed during patterning after the solvent is volatilized. It becomes difficult to transfer the mold pattern. Further, in order to reduce the viscosity of the resin composition, when a large amount of a reactive diluent is added, the curing shrinkage rate of the composition increases,
It is not preferable because the optical sheet is deformed during manufacturing or over time.

Further, it is considered that the elastic modulus of the cured coating film is reduced and the curl property is reduced by the rigidity of the transparent sheet as the base material. Here, as a method of lowering the elastic modulus of the cured coating film, as a soft segment component having a low glass transition point in the molecular structure, polyether or aliphatic polyester, polysiloxane, polyolefin, or a polyacrylate mainly containing an acrylic ester is used. A method of introducing acrylic or the like can be considered. However, the introduction of such a soft segment component reduces the hardness of the cured product,
This causes problems such as scratches on the surface and reduced durability.

In order to solve these problems, the ionizing radiation curable resin composition for optical sheets according to the present invention basically has no soft segment in the resin composition, is structurally hard, and has a hardness of the cured product. However, since the crosslink density is not high, the deformation of the sheet can be suppressed. That is, the ionizing radiation curable resin composition for an optical sheet according to the present invention has a polar functional group in the molecule, and the polar functional group has a structure for forming a hydrogen bond between the molecules. .

Generally, a hydrogen bond is formed between the X-H group of the atoms X and Y having high electronegativity and the Y atom, and examples of the atom having high electronegativity include oxygen and nitrogen atoms. To be More specifically, a hydrogen bond is formed between the hydroxyl group of X = O and the oxygen atom of Y = O contained in the epoxy acrylate or the monofunctional acrylate in the ionizing radiation curable resin composition for an optical sheet according to the present invention. It is formed.

The binding energy of hydrogen bond is 1 to 8 Kc.
Although it is al / mol, which is weaker than a normal chemical bond, a pseudo cross-linking structure is formed between molecules due to hydrogen bonds formed between the molecules. That is, hydrogen bonds formed between the molecules increase the cohesive force between the molecules, thereby increasing the curing speed and further increasing the physical strength.

As described above, the ionizing radiation-curable resin composition for an optical sheet according to the present invention has the ability to form intermolecular hydrogen bonds, and thus, compared with a resin composition composed only of hard segments, Fast curing speed,
In addition, since the cured product has toughness, the problem of cracking of the optical sheet during manufacturing and the impact resistance of the optical sheet can be improved.

That is, as the epoxy acrylate (a) having a cyclic structure of the present invention, bisphenol A type epoxy acrylate, phenol novolac, cresol novolac type epoxy acrylate, naphthalene skeleton epoxy acrylate, bisphenol F type epoxy acrylate and Those hydrogenated epoxy acrylates can be used.

The compounds having these cyclic structures generally have a higher refractive index than a resin cured product in which a soft segment and a hard segment are used in combination, and the thickness of the cured product for obtaining the desired refractive index can be set thin. There is an advantage that can be done. Brominated epoxy acrylates, which are partially brominated, are preferable because they have a higher refractive index after curing, can reduce the shape of the lens, and can obtain flame retardant properties. Further, two or more kinds of these epoxy acrylates having a cyclic structure may be used in combination.

These epoxy acrylates are obtained by reacting a glycidyl ether compound having a cyclic structure in the molecule with a compound having an ethylenically unsaturated double bond and a carboxylic acid. The glycidyl ether is opened by a carboxylic acid. It is produced by an addition reaction. At this time, the ring opening of glycidyl ether produces a secondary hydroxyl group as a residue, and this hydroxyl group becomes a proton donor that forms a hydrogen bond.

As the monofunctional acrylate (b) having a cyclic structure, a monofunctional acrylate having a saturated or unsaturated cyclic structure and a monofunctional acrylate having a heterocyclic structure as a carbon cyclic structure may be used alone or in combination of two or more kinds. They can be used in combination, and known and commonly used ones can be used. Further, a monofunctional acrylate (b) having these cyclic structures
Preferably has a polar functional group in the molecule, and these polar functional groups can form an intermolecular hydrogen bond.

Only representative examples thereof are isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl cyclocarbonate (meth) acrylate, phenoxyethyl acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, Dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, glycidyl (meth) acrylate, 2-hydroxy-3-phenoxy-propyl (meth) acrylate,

(Meth) acryloyloxyphthalic acid, phenoxyethylene glycol (meth) acrylate, adamantyl (meth) acrylate, monophorine (meth) acrylate and the like. Further, a monofunctional reactive diluent having a cyclic structure other than the monofunctional acrylate can be used in the present invention. Typical examples thereof include styrene and vinylpyrrolidone.

Examples of the polar functional group include a hydroxyl group, a cyclic ether group, a cyclocarbonate group, an amino group, a carboxyl group, an acid group such as a phosphoric acid group and a sulfonic acid group, and an alkali metal salt thereof. As the monofunctional reactive diluent having a cyclic structure having such a polar functional group, there are overlapped with those described above, but tetrahydrofurfuryl (meth) acrylate, glycidyl cyclocarbonate (meth) acrylate, phenoxyethyl acrylate, 2- Hydroxy-3-phenoxy-propyl (meth) acryl and the like can be preferably used.

In the present invention, ionizing radiation is used as the energy ray. As the ionizing radiation, visible rays, ultraviolet rays, electromagnetic waves such as X-rays, or charged particle beams such as electron beams are used. Of these, the most often practically used are
Visible rays, ultraviolet rays, or electron rays. In particular, when the resin preparation and the resin composition of the present invention are cured using visible light or ultraviolet light, the wavelength is 1,000 to
A photo (polymerization) initiator (c) that dissociates and generates radicals by ultraviolet rays or visible rays of 8,000 angstroms should be used.

As the photo (polymerization) initiator, any of known and commonly used ones can be used in combination, and typical examples thereof include 4-dimethylaminobenzoic acid and 4-dimethylaminobenzoic acid ester. , Alkoxy acetophenone, benzyl dimethyl ketal, benzophenone and benzophenone derivatives, alkyl benzoylbenzoate, bis (4-dialkylaminophenyl) ketone,

Benzyl and benzyl derivatives, benzoin and benzoin derivatives, benzoin alkyl ethers, 2-hydroxy-2-methylpropiophenone, 1
-Hydroxycyclohexyl phenyl ketone, thioxanthone and thioxanthone derivatives, 2,4,6-trimethylbenzoyldiphenoylphosphine oxide,

2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 and the like can be mentioned. .

Among these, 1-hydroxycyclohexyl phenyl ketone, thioxanthone and thioxanthone derivatives, 2,4,6-trimethylbenzoyldiphenoylphosphine oxide, 2-methyl-1-
[4- (Methylthio) phenyl] -2-morpholino-1
-Propanone, 2-benzyl-2-dimethylamino-1
One or two or more kinds of mixed systems selected from the group of-(4-morpholinophenyl) -butan-1-one are particularly preferable because they have high curability.

A publicly known and commonly used photosensitizer can be used in combination with the photo (polymerization) initiator. Examples of such photosensitizers include only amines, ureas, sulfur-containing compounds, phosphorus-containing compounds, chlorine-containing compounds, nitrites, and other nitrogen-containing compounds. .

In the manufacturing process, energy rays such as ultraviolet rays are irradiated through the surface of the transparent substrate (sheet-shaped transparent resin layer (C)) serving as a support, so that the photoinitiator that can be used is in the long wavelength region. An initiator having a light-absorbing ability is preferable,
UV light in the range of 360 nm to 450 nm, especially 400
It is desirable to use a photoinitiator that has a photoinitiating ability at 1 to 440 nm. Those that absorb light of 450 nm or more have poor stability of the composition, and it is necessary to manufacture them in an environment in which they are completely shielded from light, and their handling becomes extremely difficult.

Examples of the initiator capable of absorbing and initiating light at such a wavelength of light include 2,4,6-trimethylbenzoyldiphenoylphosphine oxide, thioxanthone and substituted thioxanthones, 2-benzyl-2-dimethylamino-1. -(4-morpholinophenyl) -butanone-
1,2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one and the like can be mentioned. When an electron beam is used, these photoinitiator and photosensitizer are unnecessary.

Epoxy acrylate having cyclic structure (a) and monofunctional acrylate having cyclic structure (b)
And a photoinitiator (c) which is added as necessary, the resin composition of the present invention has a acrylate functional group of 0.
It is necessary to be 2 to 5.0 mmol / g, and if the acrylate functional group concentration is lower than 0.2 mmol / g,
The curability decreases, the viscosity increases, and the workability deteriorates.

The acrylate functional group concentration is 5.0 m
If it is higher than mol / g, the cured sheet will curl due to curing shrinkage. 0.2 mmol / g-5.0 mmol
With an acrylate functional group concentration of / g, curability is good, it is possible to prevent deformation of the film such as curling during curing, and good surface hardness can be obtained.

The curl caused by the deformation of the optical sheet in the present invention is obtained by cutting out the produced optical lens sheet into A4 size and leaving it still on the horizontal surface with the lens forming surface facing upward, and the edge of the lens sheet is curled from the horizontal surface. The height can be evaluated by measuring the height. From the viewpoint of mountability and reliability as a lens, the curl in this evaluation method needs to be 1 mm or less.

The deformation of the optical sheet, that is, the curl property, has a strong correlation with the curing shrinkage of the resin. The cure shrinkage is calculated from the resin specific gravity (DL) before curing and the resin specific gravity (DS) after curing.
The curing shrinkage rate of the resin composition used in the present invention, which can be calculated by Equation 1, must be 5.5% or less. Curing shrinkage rate (%) = (DS-DL) / DS × 100 (Equation 1)

The optical sheet produced according to the present invention may cause a coating film defect such as a scratch on the surface of the cured product when the sheet is produced or mounted on a display. Minute scratches are fatal defects. Therefore, the resin composition used in the present invention is required to have a high surface hardness, specifically, as a pencil hardness,
According to JIS K-5400, H or more is required.

That is, the compounding ratio of the present invention is such that the epoxy acrylate (a) having a cyclic structure is 10% to 90%, preferably 30% to 85%. The photoinitiator is preferably added in the range of 0.5% by weight to 10% by weight.

The viscosity of this ionizing radiation curable resin is 1000 cps / 25 ° C. to 12000 cps /
It is preferably 25 ° C., and preferably 1000 cp
s / 25 ° C to 8000 cps / 25 ° C. Further, if necessary, in order to improve the coating property in the ionizing radiation-curable resin layer for imparting this pattern, the coating suitability, and the releasability from the mother mold, various additives such as an ultraviolet absorber are used. ,
A light stabilizer, an antioxidant, a rheology control agent, a silicon additive, a defoaming agent, etc. can be added.

In the optical sheet of the present invention, the above-mentioned ionizing radiation-curable resin composition layer (A) is optionally provided on at least one surface of the sheet-like transparent resin layer (C). After laminating via the layer (B), a mother die having a desired fine shape is brought into close contact with the ionizing radiation-curable resin composition layer (A), and the ionizing radiation-curable resin layer is cured by irradiation with ultraviolet rays. It is manufactured as an optical sheet which is peeled from the master mold and duplicated the fine structure of the master mold.

The sheet-shaped transparent resin layer (C) mentioned here
Is used for the purpose of imparting the physical strength of the optical sheet and for obtaining the smoothness of the surface on the opposite side of the master die having the fine structure. When such a sheet-shaped transparent resin layer (C) is not used for an optical sheet, in order to obtain such a smooth surface,
A transparent and smooth substrate may be brought into contact with the surface opposite to the mold having a fine structure, the smooth surface may be transferred, and the resin may be cured by UV irradiation, and then the smooth substrate may be peeled off from the UV resin layer. Will be needed.

In such a peeling step, the number of steps increases and the peelability between the transfer surface having a smooth surface and the ionizing radiation curable resin layer becomes a problem, resulting in limitation of productivity and materials. Further, the optical sheet formed only of the ionizing radiation-curable resin layer has a strength against physical shock when the optical sheet is produced, when the optical sheet is attached to the optical device, or when the optical device is used. I'm not satisfied.

Therefore, it is possible to increase the film thickness of the ionizing radiation curable resin layer to give it strength. However, when the film thickness of the ionizing radiation curable resin layer is increased, the degree of curing in the film thickness direction becomes uneven. Hardening strain is likely to occur. Therefore, integrating the sheet-shaped transparent resin layer (C) and the ionizing radiation curable resin layer (A) is a preferable method from the viewpoint of manufacturing and strength of the optical sheet.

The sheet-like transparent resin layer (C) has mechanical strength such as breaking strength and tensile strength against physical impact, and has a uniform film thickness, smoothness, transparency,
It is necessary to have flexibility and durability.

Specifically, the transparent resin layer (C) is preferably in the form of a sheet, especially from 20 μm to 1 μm.
mm is preferable, processability, film physical properties,
From the viewpoint of transparency, 50 μm to 150 μm is particularly preferable. The surface of the transparent resin layer (C) may be subjected to an easy adhesion treatment such as a corona discharge treatment, a plasma treatment, an easy adhesion primer coat or the like in order to improve the adhesion with the ionizing radiation curable resin layer (A). .

Specifically, a polyester sheet such as polyethylene terephthalate having good transparency, an acrylic sheet such as polymethylmethacrylate, a polycarbonate sheet, a vinyl chloride sheet, a polystyrene sheet or the like can be used. Particularly, from the viewpoint of durability, polyethylene terephthalate-based or polycarbonate-based sheets are preferable.

In the present invention, not only the durability of the ionizing radiation-curable resin layer (A) but also the durability of the sheet-shaped transparent resin layer (C) as a base material, and further the ionizing radiation-curable resin layer (A) Adhesion between the sheet-shaped transparent resin layer (C) and the sheet-shaped transparent resin layer (C) is also very important. It is preferable to have a layer (B).

However, the transparent resin layer (C) which becomes the base sheet
With sufficient adhesion to the ionizing radiation-curable resin layer (A), or by a corona discharge treatment on the surface of the transparent resin layer (C), a plasma treatment, an easy adhesion treatment such as an easy adhesion primer coat, etc. If the adhesion is sufficient, the adhesive layer (B)
Is unnecessary. Further, for the purpose of further strengthening the adhesiveness, the easy adhesion treatment and the adhesive layer (B) can be used together.

The adhesive layer (B) is selected from those having excellent adhesive ability to both the transparent resin layer (C) serving as a support and the ionizing radiation curable resin layer (A) forming a fine structure. There must be. As the adhesive layer (B) of the present invention, a thermoplastic resin and polyisocyanate (b2), or a resin composition of a thermoplastic resin and an acrylate compound,
Alternatively, a resin composition composed of polyisocyanate (b2) and polyester (b3) has excellent adhesion,
Particularly preferably used.

As the thermoplastic resin referred to here, known and conventional ones can be used, but preferably, various cellulose esters such as cellulose ester and cellulose ether (b1), and various (meth) acrylic acid ester polymers. Examples thereof include acrylic resin such as acrylic lacquer, polyester resin such as high molecular weight oil-free polyester, polycarbonate resin, and polyester or polyether polyurethane. Of these, the cellulose resin (b1) and the polyester resin (b3) are particularly preferable.

The cellulose ester resin referred to here is
Hydroxyl groups in cellulose are partially esterified with acids, and are obtained by esterification with one or more acids such as nitric acid, sulfuric acid, acetic acid, propionic acid, butyric acid, and other higher fatty acids. . In particular, a cellulose ester resin esterified with acetic acid, propionic acid or butyric acid is preferably used. A cellulose ether resin can be used similarly to the cellulose ester resin. Cellulose resins having ester and ether bonds are also preferably used.

The polyester resin (b3) referred to here is a known and conventional one obtained by an esterification reaction or a transesterification reaction between a saturated or unsaturated polyol and a polybasic acid or a lower alkyl ester. The molecular weight is preferably 3,000 to 30,000. As such a polyol raw material, known and conventional ones can be used, and typical examples thereof include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol,

1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4-trimethyl-1,3- Pentanediol, 3-methyl-
1,5-pentanediol, dichloroneopentylglycol, dibromoneopentylglycol, hydroxypivalic acid neopentylglycol ester, cyclohexanedimethylol,

1,4-cyclohexanediol, trimethylolethane, trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipententaerythritol, tripentaerythritol, spiroglycol, tricyclo Decane dimethylol, hydrogenated bisphenol A and the like.

Further, as the polybasic acid compound, various known and commonly used carboxylic acids or their acid anhydrides, and esterified products of these carboxylic acid compounds and lower alkyl alcohols can be used. To exemplify only the typical ones, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, het acid, hymic acid, chlorendic acid, dimer acid, adipic acid, succinic acid, alkenyl amber Acid, sebacic acid, azelaic acid,

2,2,4-trimethyladipic acid, 1,
4-cyclohexanedicarboxylic acid, terephthalic acid, 2-
Di-lower alkyl of 5-sodium-sulfoisophthalic acid, such as sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, or dimethyl- or diethyl ester. Esters, orthophthalic acid, 4-sulfophthalic acid,
1,10-decamethylenedicarboxylic acid,

Muconic acid, oxalic acid, malonic acid, glutaric acid, trimellitic acid, hexahydrophthalic acid, tetrabromophthalic acid, methylcyclohexene tricarboxylic acid or pyromellitic acid, or their acid anhydrides, or methanol, ethanol. Examples thereof include alcohol ester compounds.

As the (meth) acrylic acid ester as used herein, known and commonly used ones can be used, but more specifically, alkyl (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate, and , (Meth) acrylate having a cyclic structure, polyoxyalkylene (meth) acrylate, and the like.

Further, as the cyclic ester compound, γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, D-glucono-1,4-lactone, 1,10-phenanthrenecarbolactone, 4-
Lactones such as pentene-5-olide and 12-dodecanolide are mentioned.

As the acrylate compound which can be preferably used in the adhesive layer, those usually used as a reactive diluent, various acrylate oligomers and acrylate polymers can be used, and these acrylate compounds include epoxy acrylate, Urethane acrylate,
Polyester acrylate, polyether acrylate, etc. can be used alone or in combination of two or more kinds.

Of these, epoxy acrylate compounds are particularly preferable from the viewpoint of adhesion to the ionizing radiation curable resin layer having a fine pattern. As the epoxy acrylate used here, those exemplified in the above ionizing radiation-curable resin composition can be used, and these acrylate compounds are preferably 10% to 60% in the adhesive layer resin. .

When the content of the acrylate compound is 10% or less, the adhesion with the ionizing radiation-curable resin layer, which is the upper layer of the adhesive layer, is deteriorated, and a phenomenon such as whitening is observed in the water resistance test. Further, when the amount of the acrylate compound is 60% or more, the adverse effect that the adhesiveness with the base material is reduced is likely to occur.

Further, as the polyester or polyether type polyurethane, etc., polyester polyol, polyethylene glycol, polypropylene glycol, etc., in which the above-mentioned polyester has a molecular weight of about 500 to 4000,
A polyurethane resin obtained by reacting a polyalkylene oxide such as polytetramethylene glycol with a polyisocyanate can be used.

The polyisocyanate referred to here is
It is needless to say that the polyisocyanate in the form of isocyanurate and the isocyanate compound may be used alone or in combination, and any known and commonly used difunctional or higher isocyanate may be used. However, if only to exemplify these representative ones, tolylene diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate, dicyclohexylmethane diisocyanate or isophorone diisocyanate, such as hydrogenated xylylene diisocyanate, various alicyclic diisocyanate compounds,

Further, various compounds such as various aliphatic diisocyanate compounds such as hexamethylene diisocyanate or lysine diisocyanate can be used. Also, the above isocyanate monomer is a buret,
Alohanates, isocyanurate-polymerized isocyanate multimers, and polyisocyanates obtained by reaction with polyol can also be used. These may be used alone or in combination. Among these, a polyisocyanate compound having 3 or more isocyanate groups in the molecule is preferable, and a polyisocyanate derived from hexamethylene diisocyanate is particularly preferable.

The ratio of the thermoplastic resin to the polyisocyanate is such that the ratio of the hydroxyl group equivalent of the thermoplastic resin to the isocyanate equivalent of the polyisocyanate and the OH equivalent / NCO equivalent ratio are in the range of 0.1 to 5, preferably. , 0.1 to 1 is desirable in terms of reliability of adhesion.
Further, the thickness of the adhesive layer (B) is appropriately in the range of 0.2 μm to 10 μm.

The sheet-like transparent resin layer (C) is coated with the adhesive layer (B), and if necessary, a setting time is provided, or a temperature is applied to volatilize the solvent and the like. Thereafter, the ionizing radiation-curable resin layer (A) is coated, a mother die having a desired fine shape is brought into close contact, and in this state, the ionizing radiation-curable resin layer is cured by ionizing radiation, whereby the sheet and the ionizing radiation-curable resin are cured. Adhesion of layers can be obtained.

It is preferable to add a photo (polymerization) initiator to the adhesive layer (B), particularly to the resin composition system of the thermoplastic resin and the acrylate compound, from the viewpoint of increasing the reactivity of the adhesive layer. The above-mentioned photoinitiator can be used.

Next, the outline of the method for producing an optical sheet of the present invention will be described with reference to FIG. First, in FIG. 1, reference numeral 1 is a roll intaglio plate on which desired irregularities are formed, 2 is a recess of the roll intaglio plate 1, 3 is an uncured ionizing radiation curable resin liquid, 3a
Is a cured ionizing radiation curable resin, 4 is a sheet substrate (C) with an adhesive layer (B), 5 is a pressing roll for pressing the roll intaglio 1, 6 and 8 are feed rolls, and 7 is an ionizing radiation irradiation device. , 9 is an optical sheet, 10 is a T-die type nozzle, 11
Is a drying device, and 12 is a liquid reservoir.

As a method for filling the recesses 2 of the roll intaglio 1 with the ionizing radiation-curable resin 3, a predetermined amount of the ionizing radiation-curable resin liquid 3 is previously applied to the surface of the roll intaglio 1, as shown in FIG. After being processed, when the base sheet 4 is supplied to the roll intaglio 1, the ionizing radiation curing type coated through the base sheet 4 by the pressure from the back side of the base of the pressing roll 5. The resin liquid 3 is distributed and filled in the recess 2.

In this case, a solvent type curable resin can be used, and the solvent can be volatilized and removed by the drying device 11. The ionizing radiation irradiation device 7 may be one as shown in FIG. 1, but a plurality of curing devices may be provided to cure the resin liquid 3 in the roll intaglio 1 in multiple stages. In this way, a sufficient irradiation amount can be obtained even if the traveling speed of the sheet base material 4 is increased, and the curing strain of the resin liquid 3 and the curling and strain of the sheet base material 4 can be obtained by gradually curing. Is preferable for reducing

Next, while the sheet base material 4 is in contact with the roll intaglio 1 (specifically, when it is located between the pressure roll 5 and the feed roll 6 in the figure), an ionizing radiation irradiation device is provided. The ionizing radiation curable resin 3 is cured by 7. When the ionizing radiation is irradiated by the ionizing radiation irradiating device 7, it is performed from the side of the sheet base material 4, but the roll intaglio is formed by a material having a high ionizing radiation permeability such as quartz or glass. Irradiation can also be performed from the inside of 1 (specifically, by an irradiation device installed in the roll hollow). Irradiation may be performed from both the sheet substrate side and the intaglio inside side.

By the ionizing radiation irradiation device 7, the ionizing radiation curable resin 3 in the concave portion 2 of the roll intaglio 1 is brought into close contact with the sheet base material 4. After passing through the ionizing radiation irradiation device 7, the sheet base material 4 is peeled from the roll intaglio 1. As a result, the cured ionizing radiation-curable resin liquid 3a is integrated with the sheet base material 4 and is detached from the recess 2 to obtain the optical sheet 9 having an uneven surface.

The ionizing radiation of the ionizing radiation irradiation device means an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing and cross-linking molecules, and usually, ultraviolet rays,
An electron beam or the like is used, and in the case of ultraviolet rays, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a black light lamp or a metal halide lamp can be used.

In the case of electron beam, irradiation sources such as Cockloft-Walton type, Van de Graaff type, resonance transformer type insulating core transformer type, or various electron beam accelerators such as linear type, dynamitron type, high frequency type, etc. Can be used, and can be 100 to 1000 KeV, preferably 100
Irradiate with electrons having an energy of ~ 300 KeV. The irradiation dose is usually preferably about 0.5 to 30 Mrad.

The solvent drying device 11 is a device for volatilizing the solvent of the resin. As the solvent drying device 11, warm air, an infrared heater or the like can be used. The drying device 11 is not necessary when a solventless ionizing radiation curable resin is used.

Next, the optical sheet of the present invention and the display device using the same will be described. The display device includes various known types including a liquid crystal display device, and may be monochrome or color. Further, it is used for displaying images, numbers and characters such as clocks, electronic desk calculators, various measuring instruments, word processors, televisions, and computer displays. In addition, the fine structure for line control in the optical sheet refracts the light beam from the light source (line light source or point light source),
It converges, diverges, diffuses or transmits, or diffusely reflects, and various shapes are used.

2 to 6 are diagrams schematically showing some fine structure examples of the optical sheet manufactured by the present invention. Here, FIG. 2 shows a triangular prism type lenticular lens, FIG. 3 shows a cylindrical convex lenticular lens, FIG. 4 shows a cylindrical concave lenticular lens, FIG. 5 shows a pyramidal lens, and FIG. 6 shows a fly-eye (fly-eye) lens. .

As a master mold having a fine shape of the optical sheet, a mold for providing a Fresnel lens, a lenticular lens, a fly-eye (fly eyes) lens, or a modification thereof is, for example, a polygonal pyramid, a truncated cone, or a polygonal pyramid. It is possible to form a plurality of isotropically arranged identical shapes and shapes of the same kind on a plane. Here, if a regular pyramid (or a truncated cone), a regular quadrangular pyramid (or a truncated cone), or a regular hexagonal pyramid (or a truncated cone) is used as the pyramid or the truncated pyramid, it is possible to arrange them in a plane without a gap and the shape is isotropic. Therefore, it is possible to have the same half-value angle in both the horizontal and vertical directions, which is preferable because there is no change depending on the place.

Alternatively, a metal or a synthetic resin, which is a surface having the same shape as the shape of the optical portion, such as an array of a plurality of continuous triangular or tetrahedral prism elements, and the shape of which has an inverted concavo-convex shape. Can be used. Further, such a master block can be manufactured even if it has a fine shape on a plane or a surface of a cylindrical shape. An example of continuous production using such a cylindrical master die is US Pat. No. 368.
It is described in Japanese Patent No. 9346, Japanese Patent Application Laid-Open No. 5-169015, and the like.

[0103]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention should not be limited to these. All parts and% in the examples are on a weight basis unless otherwise specified.

(Examples 1 to 5) The compositions of the ionizing radiation curable resin composition (A) for the optical sheet and the adhesive layer (B) were prepared according to the formulations shown in Table 1. Next, as a sheet-shaped transparent resin layer (C), a transparent PET film (film thickness 100
Micron), and the adhesive layer (B) was coated thereon with a roll coater so that the dry film thickness was about 1 micron.
At this time, the solvent contained in the adhesive layer composition was adjusted to 80%.
It was dried by heat treatment at 30 ° C. for 30 seconds.

(Resin Composition of Adhesive Layer (B) of Examples 1, 4 and 5) High molecular weight oil-free polyester resin (terephthalic acid, isophthalic acid, adipic acid, ethylene glycol, 1,6-hexanediol, neo) A total of 20 parts was obtained by adding 10 parts of a condensate of pentyl glycol, a molecular weight of about 5000), 2 parts of bisphenol A epoxy acrylate, 4 parts of toluene and 4 parts of butyl acetate.

(Resin Composition of Adhesive Layer (B) of Examples 2 and 3) Cellulose acetate butyrate resin (butylation degree 37%, acetylation degree 13%, residual hydroxyl group 2%) 15
Parts, toluene 40 parts, methyl ethyl ketone 40 parts, hexamethylene diisocyanate trimethylolpropane adduct type polyisocyanate (NCO% = 16.7).
%) 5 parts, for a total of 20 parts.

Next, the method for producing the optical sheet of the present invention will be specifically described with reference to FIG. As shown in FIG.
While rotating around a shaft, a metal roll intaglio having a retroreflective lens having a shape in which a plurality of regular tetrahedrons arranged in a row at a pitch of 0 micron are two-dimensionally arranged The ionizing radiation-curable resin composition (A) is applied to the roll surface from a die-type nozzle, and at a speed synchronized with the peripheral speed of the roll intaglio plate,

Sheet-like transparent resin layer (C) (transparent PET
While the film is running, the side of the transparent PET film coated with the adhesive (B) and the surface of the roll intaglio are brought into close contact with each other with the ionizing radiation-curable resin composition (A) interposed therebetween, and the PET film is used as it is. From the side, high pressure mercury lamp (160
(W / cm) 2 lamps were irradiated from a position of 10 cm to cure the resin layer and at the same time, to bond it to the PET film.

At this time, the irradiation amount of the ultraviolet rays with which the surface of the PET film was irradiated was 500 mj / cm ² . After curing, the PET film was peeled off together with the ionizing radiation curable resin layer from the roll intaglio plate to produce a continuous optical sheet in which the desired roll intaglio plate shape was transferred. Tables 5 to 7 show the results of evaluating the physical properties of the optical sheet and the cured resin.

[0110]

(Epoxy acrylate having a cyclic structure and having two or more acrylate groups) a1: bisphenol A epoxy acrylate a2: brominated bisphenol A acrylate

(Monofunctional acrylate having a cyclic structure) b1: Isobornyl acrylate b2: Glycidyl cyclocarbonate methacrylate b3: Tetrahydrofurfuryl acrylate b4: 2-Hydroxy-3-phenoxy-propyl (meth) acrylate

(Photoinitiator) c1: 1-hydroxycyclohexyl phenyl ketone c2: benzyl dimethyl ketal

(Comparative Examples 1 to 4) Except that the ionizing radiation curable resin layers of Comparative Examples 1 to 4 were prepared according to the formulations shown in Table 2.
Optical sheets were manufactured in the same manner as in Examples 1 to 5. The evaluation results are shown in Tables 5-7.

[0115]

(Acrylate of Comparative Example) e1: dipentaerythritol hexaacrylate e2: polyethylene glycol diacrylate (molecular weight about 370)

Comparative Examples 5 and 6 The same as Examples 1 to 5 except that the ionizing radiation curable resin layers of Comparative Examples 5 to 8 were prepared by the formulations of Table 3 and the formulation of the adhesive layer shown below. An optical sheet was manufactured by the method. The evaluation results are shown in Tables 5-7.

[0118]

(Resin Composition of Adhesive Layers of Comparative Examples 5 and 6) High molecular weight oil-free polyester resin (terephthalic acid,
Isophthalic acid, adipic acid, ethylene glycol, 1,
A total of 20 parts was obtained by condensing 6-hexanediol and neopentyl glycol, having a molecular weight of about 5,000 (12 parts), toluene (4 parts) and butyl acetate (4 parts).

(Comparative Examples 7 and 8) Ionizing radiation-curable resins were prepared according to the formulations shown in Table 3 and were coated on a transparent PET film.
An optical sheet was prepared by using the same device and the same method as those of the examples without coating the adhesive layer. Table 5-7 shows the evaluation results.
Shown in.

Comparative Example 9 667 parts of isophorone diisocyanate and 0.01 stannous chloride were placed in a reactor equipped with a stirrer, a thermometer, an addition funnel, and a dry air sparger.
5 parts were charged and heated to 70 ° C. While stirring the reaction contents, heated polycaprolactone diol (TON
E P0201) 795 parts was added.

The mixture was stirred for 13 hours at 70 ° C. to produce a polycaprolactone urethane polymer having a terminal isocyanate. Next, 2-hydroxyethyl methacrylate 400
Parts were added over 3.5 hours. Until the residual isocyanate is not substantially observed by the infrared spectrum,
The reaction continued for about 13 hours.

Next, to this urethane acrylate, 2
(N-Butylcarbamyl) ethyl methacrylate 46
5.5 parts and 11.6 parts of 2,2-diethoxyacetophenone as a photoinitiator were added and mixed and dissolved to prepare a desired curable composition of Example 2 described in US Pat. No. 4,576,850.

(Measurement / Evaluation Method) The measurement / evaluation method will be described below.

(1) Viscosity Measurement Viscosity measurement (cps) at 25 ° C. was performed using an E-type rotational viscometer.

(2) Judgment of Initial Appearance The appearance of the manufactured optical sheet was visually judged. Judgment criteria are as follows: a uniform lens surface shape was obtained, a partial crack or shape omission was observed, and a crack or shape omission was observed on the entire surface. did.

(3) Pencil Hardness Measurement The pencil hardness was measured according to JIS K5400. A value of H or more was evaluated as ◯, and a value of F or less was evaluated as x.

(4) Initial Adhesion Measurement Adhesion between the transparent PET of the substrate and the ionizing radiation curable resin layer forming the optical sheet layer was measured according to JIS K5400.

(5) Measurement of Boiling Water Adhesion The prepared optical lens sheet was dipped in boiling water at 95 ° C. or higher for 4 hours.
Soak for 2 hours, remove to room temperature, and measure the adhesion after 2 hours.
It was measured according to IS K5400. 100/100
Indicates that all the pieces were in close contact. 0/100 indicates that all the small pieces were peeled off.

(6) Appearance evaluation after boiling water The prepared optical lens sheet was dipped in boiling water at 95 ° C or higher for 4 hours.
It was immersed for a period of time, taken out at room temperature, and the appearance of the coating film was visually evaluated.

(7) Accelerated weathering adhesion The prepared optical lens sheet was measured with a fade meter (Suga tester: black panel temperature: 63 ± 3 ° C.) at 400
Time-accelerated weathering test was performed to determine adhesion according to JIS K5
It measured based on 400.

(8) Curling property measuring method The prepared optical sheet was cut out into A4 size and left still on the horizontal surface with the sheet forming surface upward, and the edge of the optical sheet naturally curled from the horizontal surface (mm). ) Was measured.

(9) Method of Measuring Curing Shrinkage Rate The ionizing radiation curable resin compositions of Examples and Comparative Examples were placed in stainless steel pans having an inner diameter of 30 mm and a height of 10 mm, respectively.
High pressure mercury lamp (80W / cm)
1 in an air atmosphere using the conveyor type ultraviolet irradiation device
A cured product for specific gravity measurement was prepared by irradiating ultraviolet rays of 000 mj / cm ² .

The specific gravity (DS) of the cured product was measured at 23 ± 2 ° C. according to JIS K7112 B method. However, distilled water was used as the immersion liquid, the specific gravity (DL) of the resin composition was measured at 23 ± 2 ° C., and the curing shrinkage rate was calculated by the following formula. The measurement result is shown as an average value of two measurement results. Curing shrinkage rate (%) = (DS-DL) / DS × 100

(10) Curability 1 A high pressure mercury lamp of 80 W / cm, a lamp height of 15 cm,
When irradiation was performed at a line speed of 10 m / min, the number of irradiations until surface tack free was measured. The smaller the number of irradiations, the better the curability.

(11) Curability 2 Photo DSC (Perkin Elmer Co., Ltd., DPA
-7 type) shows the reaction rate constant (under nitrogen atmosphere).

(12) Surface hardness Ionizing radiation curing in air (high pressure mercury lamp; 80 W / cm,
The pencil hardness of the surface when subjected to 1000 mj / cm ² ) is shown.

(13) Refractive index The compositions of Examples 1 to 5 and Comparative Example 9 were placed on a glass plate to give 5
The coating was applied to a thickness of 0 μm and irradiated with 1000 mj / cm ² of ultraviolet rays by a high pressure mercury lamp (80 W / cm) to cure it. The cured layer was peeled from the glass plate to prepare a sample. 1-Bromonaphthalene was used as an intermediate solution for bringing the sample into close contact with the prism, and the sample was measured with an Abbe refractometer at a sample temperature of 25 ° C. The results are shown in Table 9.

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

INDUSTRIAL APPLICABILITY The present invention is useful for Fresnel lenses, lenticular lenses, back reflection lenses and the like, has a high surface hardness, does not have the problem of deformation at the time of curing and deterioration of weather resistance, and has a short curing time, which improves productivity. An excellent ionizing radiation curable resin composition for an optical sheet having a fine structure on the surface, an optical sheet, and a method for producing the same can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a continuous manufacturing method of an optical sheet according to the present invention.

FIG. 2 is a diagram schematically showing an example of an optical sheet according to the present invention.

FIG. 3 is a diagram schematically showing an example of an optical sheet according to the present invention.

FIG. 4 is a diagram schematically showing an example of an optical sheet according to the present invention.

FIG. 5 is a diagram schematically showing an example of an optical sheet according to the present invention.

FIG. 6 is a diagram schematically showing an example of an optical sheet according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 roll intaglio 2 recesses 3 uncured ionizing radiation curable resin composition (A) 3a cured ionizing radiation curable resin composition (A) 4 sheet substrate (C) 5 with an adhesive layer (B) 5 pressing roll 6 Feed Roll 7 Curing Device 8 Feed Roll 9 Optical Sheet 10 T Die Type Nozzle 11 Drying Device 12 Liquid Reservoir

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G03F 7/028 // B29K 63:00 B29L 11:00 (72) Inventor Toshikazu Nishio Shinjuku-ku, Tokyo Ichigaya Kagacho 1-1-1 Dai Nippon Printing Co., Ltd. (72) Inventor Hiroyuki Amemiya 1-1-1 Ichigaya Kagacho Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. (72) Inventor Michiko Takeuchi Tokyo 1-1-1 Ichigaya-Kagacho, Shinjuku-ku Dai Nippon Printing Co., Ltd.

Claims (18)

[Claims] 1. An epoxy acrylate (a) having a cyclic structure and having two or more acrylate groups, a monofunctional acrylate (b) having a cyclic structure, and a photoinitiator (c) optionally added. ), The acrylate functional group is 0.2 to 5.0 mmol / g, the viscosity at 25 ° C. is 1000 to 12000 cps, and the cure shrinkage calculated by Formula 1 is 5.5% or less. An ionizing radiation curable resin composition for an optical sheet, comprising: Curing shrinkage (%) = (DS-DL) / DS × 100 (Equation 1) (where DL represents the specific gravity of the composition before curing, and DS represents the specific gravity after curing). 2. The epoxy acrylate (a) having a cyclic structure and having two or more acrylate groups is an epoxy acrylate having a structure of bisphenol A and / or hydrogenated bisphenol A. 1. The ionizing radiation curable resin composition for an optical sheet according to 1. 3. The epoxy acrylate (a) having a cyclic structure and having two or more acrylate groups is an epoxy acrylate having a partially halogen-substituted bisphenol A and / or hydrogenated bisphenol A structure. A resin composition for an optical sheet according to claim 1. 4. The resin composition for an optical sheet according to claim 1, wherein the monofunctional acrylate (b) having a cyclic structure is isobornyl (meth) acrylate. 5. The resin composition for an optical sheet according to claim 1, wherein the monofunctional acrylate (b) having a cyclic structure is glycidyl cyclocarbonate (meth) acrylate. . 6. The resin composition for an optical sheet according to any one of claims 1 to 4, wherein the monofunctional acrylate (b) having a cyclic structure is tetrahydrofurfuryl (meth) acrylate. . 7. The monofunctional acrylate (b) having a cyclic structure is 2-hydroxy-3-phenoxy-propyl (meth) acrylate.
5. The resin composition for an optical sheet according to any one of items 1 to 4. 8. An ionizing radiation curable resin composition layer (A) having a fine structure, comprising the ionizing radiation curable resin composition for an optical sheet according to any one of claims 1 to 7.
An optical sheet comprising an adhesive layer (B) provided as necessary and a sheet-shaped transparent resin layer (C). 9. The adhesive layer (B) is a cellulose resin (b).
9. The optical sheet according to claim 8, which comprises 1) and polyisocyanate (b2). 10. The adhesive layer (B) comprises a polyester resin (b3) having a molecular weight of 3,000 to 30,000 and a polyisocyanate (b2).
The optical sheet described. 11. The adhesive layer (B) comprises a polyester resin (b3) having a molecular weight of 3000 to 30000, an epoxy acrylate having a cyclic structure, and a photoinitiator, and the content of the epoxy acrylate is 10%. The optical sheet according to claim 8, which is -60%. 12. The optical sheet according to claim 8, wherein the sheet-shaped transparent resin layer (C) is a polyester or a polycarbonate resin. 13. A layer (A) having a fine structure comprising the ionizing radiation-curable resin composition for an optical sheet according to claim 1, and a cellulose resin (b1).
And an adhesive layer (B) composed of polyisocyanate (b2)
And a sheet-shaped transparent resin layer (C) made of polyester or polycarbonate resin. 14. A layer (A) having a fine structure, which comprises the ionizing radiation-curable resin composition for an optical sheet according to claim 1, and a molecular weight of 3000 to 300.
00 polyester resin (b3) and polyisocyanate
An optical sheet comprising an adhesive layer (B) composed of a sheet (b2) and a sheet-shaped transparent resin layer (C) composed of polyester or polycarbonate resin. 15. A layer (A) having a fine structure, comprising the ionizing radiation-curable resin composition for an optical sheet according to claim 1, and a molecular weight of 3000 to 300.
No. 00 polyester resin, an epoxy acrylate having a cyclic structure, a photoinitiator, and an adhesive layer (B) made of a resin composition having an epoxy acrylate content of 10% to 60%, polyester or An optical sheet comprising a sheet-shaped transparent resin layer (C) made of a polycarbonate resin. 16. A filling step of rotating a roll intaglio on which a mold having a desired fine concavo-convex shape is formed, and filling at least a concave portion of the roll intaglio plate with an ionizing radiation-curable resin liquid; A contact step of bringing a transparent resin sheet base material traveling in synchronism with the rotation direction of the roll intaglio into contact with the filled ionizing radiation-curable resin liquid; and in the contact step, the sheet base material is the roll intaglio plate. Curing step of irradiating the ionizing radiation-curable resin liquid between the roll intaglio plate and the sheet base material with ionizing radiation while being in contact with; and the ionizing radiation-curable resin cured in the curing step. A contact step of bringing the liquid and the sheet base material into close contact with each other; a cured product of the ionizing radiation-curable resin liquid and the sheet base material, which have been adhered in the contact step, are peeled off from the roll intaglio plate. A releasing step; and the ionizing radiation-curable resin liquid is the ionizing radiation-curable resin composition for an optical sheet according to any one of claims 1 to 7. . 17. A step of coating an adhesive layer on a transparent resin sheet base material; rotating a roll intaglio on which a mold having a desired fine concavo-convex shape is rotated, and an ionizing radiation curable resin liquid at least in the recess of the roll intaglio. And a filling step of filling the roll intaglio plate in the filling step with the ionizing radiation-curable resin liquid, the adhesive layer of the transparent resin sheet base material running in synchronization with the rotation direction of the roll intaglio plate. A contact step of contacting sides; and irradiating the ionizing radiation to the ionizing radiation curable resin liquid between the roll intaglio and the sheet base material while the sheet base material is in contact with the roll intaglio plate in the contact step. And a curing step of curing the ionizing radiation-curable resin liquid that is cured in the curing step and the sheet base material through an adhesive layer; The cured product of a radiation-curable resin liquid and a peeling step of peeling the sheet base material from the roll intaglio, wherein the ionizing radiation-curable resin liquid is the optical material according to any one of claims 1 to 7. An ionizing radiation curable resin composition for a sheet, which is a method for producing an optical sheet. 18. The absorption wavelength of the photoinitiator contained in the adhesive layer (B) is 400 nm or less, and the absorption wavelength of the photoinitiator contained in the ionizing radiation-curable resin composition layer (A) is It exists below 450 nm, It is characterized by the above-mentioned.
The method for producing an optical sheet according to 6 or 17.