JP2007108408A - Manufacturing method of optical sheet, the optical sheet and manufacturing device of the optical sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique of manufacturing high-quality optical sheets by appropriately pressing a pattern roller against a member, such as resin. <P>SOLUTION: A web W coated with optical resin is nipped by an embossing roller 13 and a nip roller 14, and is wound around the embossing roller 13, a prescribed pattern formed on the embossing roller 13 is transferred to the optical resin, and thereby an optical sheet is manufactured. Therein, nip pressure P (MPa) against the web W by means of the embossing roller 13 and the nip roller 14 and viscosity η(mPa s) of an optical member are set so as to satisfy relation; (1/2)×log<SB>10</SB>η-3≤log<SB>10</SB>P≤(1/2)×log<SB>10</SB>η-2, (1≤η≤10,000). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical sheet having a predetermined pattern formed on the surface and a method for manufacturing the same, and, for example, to a technique applicable to a prism sheet having a predetermined uneven pattern formed on the surface and used in a liquid crystal display device or the like.

  In order to make the display of an electronic display such as a liquid crystal display clear, an optical sheet such as a prism sheet on which a predetermined uneven pattern is formed is used to adjust the brightness of the display. As a method for producing such an optical sheet, for example, a method of producing an optical sheet by applying a photocurable resin on a support and forming a predetermined uneven pattern on the photocurable resin is known. In this case, since the optical characteristics of the optical sheet change according to the application accuracy of the photocurable resin to the support, it is important that the photocurable resin is appropriately applied on the support. Under such circumstances, several techniques for appropriately applying an optical member such as a photo-curing resin on a support have been proposed.

For example, Patent Document 1 discloses a film manufacturing apparatus that cures a resin to form a desired uneven pattern on a film. This manufacturing apparatus has been proposed for the purpose of making it difficult to produce an incompletely shaped film.
JP-A-11-300768

  With the recent increase in demand for electronic displays, the demand for optical sheets such as prism sheets is also increasing. In addition, the use of the concavo-convex sheet represented by the prism sheet is diverse, and the technical field that requires the concavo-convex sheet is expected to further expand in the future. Therefore, it is socially desired that rugged sheets of various sizes are manufactured in large quantities.

  However, as the size of the concavo-convex sheet increases, and the production speed of the concavo-convex sheet increases, manufacturing errors tend to occur and it becomes difficult to ensure a certain high quality. In particular, when a predetermined concavo-convex pattern is formed on a resin by pressing the pattern roll against a liquid or semi-liquid resin, the quality of the concavo-convex sheet is greatly influenced by the magnitude of the pressing force of the pattern roll against the resin. The For example, when the pressing force of the pattern roll against the resin is small, air is caught in the resin, and the surface state of the resin is deteriorated. Further, when the pressing force of the pattern roll against the resin is large, streaky unevenness occurs in the resin, and the surface state of the resin is deteriorated. Further, when a resin having a high viscosity is used, the application state of the resin on the support tends to be uneven, and the quality of the optical sheet formed by the resin may be deteriorated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical sheet manufacturing method capable of manufacturing a high-quality optical sheet by appropriately pressing a pattern roll against a member such as a resin. It is to provide the technology about.

In order to solve the above-mentioned problems, an optical sheet manufacturing method according to an aspect of the present invention is formed on a pattern roll by niping a support coated with an optical member between a pattern roll and an entrance roll and winding the support around the pattern roll. An optical sheet manufacturing method for manufacturing an optical sheet by transferring a predetermined pattern to the optical member, the nip pressure P (MPa) on the support by the pattern roll and the inlet roll, and the viscosity of the optical member η (mPa · s) is set so as to satisfy the relationship of (1/2) × log ₁₀ η−3 ≦ log ₁₀ P ≦ (1/2) × log ₁₀ η−2 (1 ≦ η ≦ 10000). Is done.

  According to this aspect, the nip pressure P is set in a preferable range with respect to the viscosity η of the optical member, and a high-quality optical sheet can be manufactured by pressing the pattern roll against the optical member with an appropriate force. it can.

  In addition, an optical member refers to the whole member to which an optical function is provided, and members, such as resin generally used, are contained in an optical member. The optical member may be in a liquid state, a solid state, or an intermediate state between the liquid and the solid.

  The optical sheet refers to all sheets having optical functions. For example, an uneven optical sheet such as a prism sheet, a fly-eye lens sheet (an eyelet lens sheet), or a lenticular sheet is an optical sheet. include.

  Moreover, it is preferable that at least an entrance roll is formed by a rigid member among a pattern roll and an entrance roll. Such an entrance roll has a very small change in shape with respect to the load, and thus the support on which the optical member is applied can be appropriately held together with the pattern roll. Here, examples of the rigid body include metals and ceramics.

  The viscosity η (mPa · s) of the optical member may satisfy 10 ≦ η ≦ 1000. In this case, the viscosity η of the optical member is set in a more preferable range, and the pattern roll can be pressed against the optical member with a more appropriate force.

  The variation in the distance between the pattern roll and the entrance roll may be 50 μm or less. In this case, since the variation in the distance between the pattern roll and the entrance roll is reduced, the nip pressure by the entrance roll and the pattern roll applied to the support coated with the optical member is made uniform. Thereby, the pattern roll can be pressed against the optical member with a uniform force, and a high-quality optical sheet can be manufactured.

  The variation in the diameter of the entrance roll may be 50 μm or less. In this case, since the variation in the distance between the center axis of the entrance roll and the circumference is reduced, the nip pressure by the entrance roll and the pattern roll applied to the support on which the optical member is applied is made uniform. The Thereby, the pattern roll can be pressed against the optical member with a uniform force, and a high-quality optical sheet can be manufactured.

  Another aspect of the present invention is an optical sheet manufactured by the above-described optical sheet manufacturing method. According to this aspect, the pattern roll is pressed against the optical member with an appropriate force, and a high-quality optical sheet is provided.

Another aspect of the present invention is an optical sheet manufacturing apparatus. This apparatus is an optical sheet manufacturing apparatus for manufacturing an optical sheet, and sandwiches a pattern roll having a predetermined pattern and a support coated with an optical member together with the pattern roll, and the predetermined pattern of the pattern roll is optical member. And an entrance roll to be transferred. The nip pressure P (MPa) on the support by the pattern roll and the inlet roll and the viscosity η (mPa · s) of the optical member are (1/2) × log ₁₀ η−3 ≦ log ₁₀ P ≦ (1/2 ) × log ₁₀ η−2 (1 ≦ η ≦ 10000).

  According to this aspect, a high-quality optical sheet can be manufactured by pressing the pattern roll against the optical member with an appropriate force.

  According to the present invention, the pattern roll is pressed against the optical member with an appropriate force corresponding to the viscosity of the optical member, and a high-quality optical sheet is provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram showing a configuration of an embossed sheet manufacturing apparatus 10. The embossed sheet manufacturing apparatus 10 includes a web supply unit 11, a coating unit 12, a drying unit 19, a nip roll (entrance roll) 14, and an embossing roll (pattern roll) 13 that is an uneven roll, which are sequentially arranged from upstream to downstream. , A resin curing unit 15, a peeling roll 16, a protective film supply unit 17, and a sheet winding unit 18.

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

  The application unit 12 is an apparatus that sequentially applies resin to the surface of the web W and forms a resin layer on the web W.

  FIG. 2 is a cross-sectional view showing the positional relationship between the web W and the resin layer L. The resin layer L is a part constituting a concavo-convex sheet (prism layer) provided as a final product, and a predetermined concavo-convex pattern is formed by the embossing roll 13 installed in the subsequent stage. In addition, the sheet-like laminated body comprised by the web W and the resin layer L is hereafter called "resin coating sheet S".

  As shown in FIG. 1, the application unit 12 includes a resin supply tank (resin supply source) 12 </ b> A that supplies resin, an application head 12 </ b> C that discharges resin, and a liquid feed that sends resin from the resin supply tank 12 </ b> A to the application head 12 </ b> C. It includes a pump 12B and a support roller 12D that wraps and supports the web W to be coated with resin. In addition, piping and a pump for supplying resin from the resin supply tank 12A to the coating head 12C are provided.

  A coating head 12C shown in FIG. 1 is an extrusion type die coater, and discharges the liquid to be discharged stored in the liquid reservoir from the tip of the head through the slit-shaped flow path. The coating head 12C is not limited to the above-described extrusion type die coater, and any type of ejection head can be used, and the resin can be appropriately coated on the web W. Anything is acceptable.

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

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

FIG. 3 is a diagram showing an outline of a cross section of the embossing roll 13. As for the embossing roll 13 shown by FIG. 1 and FIG. 3, the fine uneven | corrugated predetermined pattern is formed in the surface. Therefore, when the embossing roll 13 is pressed against the resin layer L of the resin-coated sheet S, an uneven pattern on the roll surface is transferred and formed on the resin layer L. For this reason, the embossing roll 13 is required to have the precision of the uneven pattern, the mechanical strength, the roundness, etc. adjusted appropriately. As such an embossing roll 13, for example, a metal rigid roll is preferable.

  The fine uneven pattern on the outer peripheral surface of the embossing roll 13 is required to be a shape pattern obtained by inverting the fine uneven pattern on the surface of the embossed sheet provided as a product. As the embossed sheet thus provided, for example, a sheet in which fine uneven patterns are two-dimensionally arranged like a lenticular lens or a prism sheet, a sheet in which fine uneven patterns are three-dimensionally arranged like a fly-eye lens, A sheet or the like in which fine cones such as a cone and a pyramid are arranged in the X and Y directions like a flat lens is an object. Therefore, the fine uneven pattern on the outer peripheral surface of the embossing roll 13 needs to correspond to the fine uneven pattern on the surface of the embossed sheet.

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

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

  As shown in FIG. 1, the nip roll 14 is a roll forming that presses the resin layer L on the web W in a pair with the embossing roll 13 and transfers a predetermined uneven pattern of the embossing roll 13 to the resin layer L. Processing. For this reason, the nip roll 14 is required to have its mechanical strength, roundness, etc. adjusted appropriately. Examples of the member constituting the nip roll 14 include metal, ceramic, rubber such as silicon rubber, and the like. If the longitudinal elastic modulus (Young's modulus) of the surface of the nip roll 14 is too small, the roll forming process tends to be insufficient. On the other hand, when the longitudinal elastic modulus (Young's modulus) of the surface of the nip roll 14 is too large, the influence of foreign matters such as dust becomes large. Therefore, the longitudinal elastic modulus of the nip roll 14 surface is preferably set to an appropriate value.

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

  The resin curing unit 15 is a light irradiation hand throw provided so as to face the embossing roll 13 on the downstream side of the nip roll 14. The resin curing unit 15 radiates light (radiation) having a wavelength corresponding to the curing characteristics of the resin layer L with a light amount corresponding to the conveyance speed of the resin coated sheet S. The light emitted by the resin curing unit 15 transmits the web W and cures the resin layer L. As such a resin hardening part 15, the columnar lamp of the length substantially the same as the width | variety of the resin application sheet S is employable, for example. Note that a plurality of the cylindrical lamps may be provided in parallel, and a reflector may be provided on the back surface of the cylindrical lamp.

  The peeling roll 16 is paired with the embossing roll 13 to peel the resin coated sheet S from the embossing roll 13. That is, the resin coating sheet S wound on the peripheral surface of the embossing roll 13 is sandwiched between the embossing roll 13 and the peeling roll 16 at the peeling portion and wound around the peeling roll 16. Thereby, the resin coating sheet S which has the cured resin layer L in which the predetermined pattern was formed is peeled from the embossing roll 13 and sent to the subsequent stage. Such a peeling roll 16 is required to have its mechanical strength, roundness, etc. adjusted appropriately. Moreover, when the temperature of resin etc. rises by hardening, in order to improve the peelability of the resin coating sheet S by cooling the resin coating sheet S at the time of peeling, an arbitrary cooling device is provided in the peeling roll 16. Is preferred.

  Although not shown in the figure, the resin-coated sheet S is wound between the pressing portion by the nip roll 14 (position at 9 o'clock in FIG. 1) and the peeling portion by the peeling roll 16 (position at 3 o'clock in the drawing). A plurality of backup rolls may be provided so as to face the embossing roll 13 formed. In this case, since the resin layer L is cured while the resin coating sheet S is supported by the plurality of backup rolls and the embossing rolls 13, the predetermined uneven pattern of the embossing rolls 13 is accurately transferred to the resin layer L. .

  The sheet winding unit 18 includes a winding roll that winds the resin coated sheet S, and winds and stores the resin coated sheet S peeled from the embossing roll 13. When the resin coated sheet S is stored by the sheet winding unit 18, the protective film H is supplied from the protective film supply unit 17 onto the resin coated sheet S, and the web W, the resin layer L, and the protective film H are formed. In the overlapped state, the sheet is wound around the sheet winding unit 18.

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

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

  In the embossed sheet manufacturing apparatus 10 having the above-described configuration, each roll is provided with an arbitrary drive device, and each roll is rotated in the direction of the arrow in the drawing by these drive devices.

  Next, the relationship between the nip pressure P by the embossing roll 13 and the nip roll 14 with respect to the resin coated sheet S and the viscosity η of the resin of the resin layer L on the web W will be described.

  In the present embodiment, the nip pressure P applied to the resin coated sheet S by the embossing roll 13 and the nip roll 14 is determined according to the viscosity η of the UV curable resin constituting the resin layer L. That is, the nip pressure P (MPa) applied to the resin coated sheet S and the viscosity η (mPa · s) of the UV curable resin are determined so that the following expression (1) is satisfied.

(1/2) × log ₁₀ η−3 ≦ log ₁₀ P ≦ (1/2) × log ₁₀ η−2
(1 ≦ η ≦ 10000)
FIG. 4 shows the relationship between the nip pressure P (vertical axis) applied to the resin coated sheet S by the embossing roll 13 and the nip roll 14 and the viscosity η (horizontal axis) of the UV curable resin constituting the resin layer L. FIG. The hatched portion in FIG. 4 indicates a range that satisfies the above formula (1).

  By determining the nip pressure P applied to the resin coated sheet S based on the above formula (1), the surface shape of the resin layer L on which the predetermined uneven pattern is formed by the embossing roll 13 is stabilized, and the size of the resin layer L is increased. Experiments have confirmed that the influence of the transfer speed of the predetermined uneven pattern on the quality of the resin layer L can be reduced. Therefore, by determining the nip pressure P so that the above formula (1) is satisfied, it becomes possible to manufacture a large number of resin layers L of various sizes on which a predetermined uneven pattern is formed with stable quality. In addition, according to the experiment, when the viscosity η (mPa · s) of the resin is set in a range satisfying the following expression (2), the planar shape of the resin layer L on which the predetermined uneven pattern is formed by the embossing roll 13. Was confirmed to be more stable.

10 ≦ η ≦ 1000 (2)
Further, when the embossing roll 13 and the nip roll 14 in which the variation in the distance between the embossing roll 13 and the nip roll 14 is 50 μm or less and the variation in the diameter of the nip roll 14 is set to 50 μm or less are used, a predetermined uneven pattern is formed. It was confirmed that the surface shape of the resin layer L was further stabilized. FIG. 5 is a perspective view showing a configuration of the nip roll 14, and a dotted line in the figure indicates a rotation axis of the nip roll 14. When the variation in diameter (for example, diameter 1, diameter 2, diameter 3 in FIG. 5) at different locations of the embossing roll 13 is 50 μm or less, the surface of the resin layer L is stabilized.

  Next, each material used in this embodiment will be described.

  As the material of the web W, a resin film, paper (resin coated paper, synthetic paper, etc.), metal foil (aluminum web, etc.) and the like can be used. As the material of the resin film, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyester, polyolefin, acrylic, polystyrene, polycarbonate, polyamide, PET (polyethylene terephthalate), biaxially stretched polyethylene terephthalate, Known materials such as polyethylene naphthalate, polyamideimide, polyimide, aromatic polyamide, cellulose acylate, cellulose triacetate, cellulose acetate propionate, and cellulose diacetate can be used. Of these, polyester, cellulose acylate, acrylic, polycarbonate, and polyolefin are particularly preferable.

  The width of the web W is generally 0.1 to 3 m, the length of the web W is generally 1000 to 100,000 m, and the thickness of the web W is generally 1 to 300 μm. Is done. However, sizes other than these may be applied.

  These webs W may be subjected in advance to corona discharge, plasma treatment, easy adhesion treatment, heat treatment, dust removal treatment, and the like. The surface roughness Ra of the web W is preferably 3 to 10 nm at a cutoff value of 0.25 mm.

  Note that the web W may be provided with a dry-cured base layer such as an adhesive layer in advance, or another functional layer may be provided in advance on the back surface. Further, as the web W, not only one composed of one layer but also one composed of two or more layers can be adopted. The web W is preferably a transparent body or an anti-transparent body that transmits light.

  Resins that can be used in this embodiment include radicals and cations capable of reacting reactive group-containing compounds such as (meth) acryloyl groups, vinyl groups, and epoxy groups with radiation groups such as ultraviolet rays. A compound containing a compound that generates an active species such as In particular, from the speed of curing, a combination of a reactive group-containing compound (monomer) containing an unsaturated group such as a (meth) acryloyl group or a vinyl group and a radical photopolymerization initiator that generates radicals by light is used. preferable. Of these, (meth) acryloyl group-containing compounds such as (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, and polyester (meth) acrylate are preferable. As the (meth) acryloyl group-containing compound, a compound containing one or more (meth) acryloyl groups can be used. Moreover, the reactive group containing compound (monomer) containing unsaturated groups, such as said acryloyl group and a vinyl group, may be used independently or may be used in mixture of multiple types as needed.

  Examples of such (meth) acryloyl group-containing compounds include monofunctional monomers containing only one (meth) acryloyl group-containing compound. As such monofunctional monomers, isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) Acrylate, benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth ) Acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, isobutyl (Meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, iso Stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, polyethylene Glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxy ethylene glycol (meth) acrylate, ethoxyethyl (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate.

  Furthermore, as a monofunctional monomer having an aromatic ring, phenoxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, 4-phenylphenoxyethyl (meth) acrylate, 3- (2-phenylphenyl) -2-hydroxypropyl (meth) acrylate, and p-cumylphenol reacted with ethylene oxide ( (Meth) acrylate, 2-bromophenoxyethyl (meth) acrylate, 4-bromophenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylate, 2,6-dibromophenoxyethyl ( Data) acrylate, 2,4,6-bromophenyl (meth) acrylate, 2,4,6-tribromophenoxyethyl (meth) acrylate.

  Examples of such commercially available aromatic monocyclic monocyclic monomers include Aronix M113, M110, M101, M102, M5700, TO-1317 (above, manufactured by Toagosei Co., Ltd.), Biscote # 192, # 193, # 220, 3BM (Osaka Organic Chemical Co., Ltd.), NK Ester AMP-10G, AMP-20G (Shin Nakamura Chemical Co., Ltd.), Light Acrylate PO-A, P-200A, Epoxy Ester M-600A, light ester PO (above, manufactured by Kyoeisha Chemical Co., Ltd.), New Frontier PHE, CEA, PHE-2, BR-30, BR-31, BR-31M, BR-32 (above, Daiichi Kogyo) Pharmaceutical Co., Ltd.).

  Examples of unsaturated monomers having two (meth) acryloyl groups in the molecule include alkyl diols such as 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, and 1,9-nonanediol diacrylate. Examples include polyalkylene glycol diacrylates such as diacrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol diacrylate, and tripropylene glycol diacrylate, neopentyl glycol di (meth) acrylate, and tricyclodecane methanol diacrylate.

  As unsaturated monomers having a bisphenol skeleton, ethylene oxide-added bisphenol A (meth) acrylic acid ester, ethylene oxide-added tetrabromobisphenol A (meth) acrylic acid ester, propylene oxide-added bisphenol A (meth) acrylic acid ester, propylene oxide-added Tetrabromobisphenol A (meth) acrylic acid ester, bisphenol A epoxy (meth) acrylate obtained by epoxy ring-opening reaction of bisphenol A diglycidyl ether and (meth) acrylic acid, tetrabromobisphenol A diglycidyl ether and (meth) Tetrabromobisphenol A epoxy (meth) acrylate, bisphenol F diglycidyl ether and (meth) obtained by epoxy ring-opening reaction with acrylic acid Bisphenol F epoxy (meth) acrylate obtained by epoxy ring-opening reaction with crylic acid, tetrabromobisphenol F epoxy (meth) acrylate obtained by epoxy ring-opening reaction of tetrabromobisphenol F diglycidyl ether and (meth) acrylic acid Etc.

  Commercially available unsaturated monomers having such a structure include Biscote # 700 and # 540 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), Aronix M-208, M-210 (above, Toagosei Co., Ltd.) ), NK ester BPE-100, BPE-200, BPE-500, A-BPE-4 (above, Shin-Nakamura Chemical Co., Ltd.), light ester BP-4EA, BP-4PA, epoxy ester 3002M, 3002A 3000M, 3000A (above, manufactured by Kyoeisha Chemical Co., Ltd.), KAYARAD R-551, R-712 (above, manufactured by Nippon Kayaku Co., Ltd.), BPE-4, BPE-10, BR-42M (above, No. 1) Manufactured by Ichi Kogyo Seiyaku Co., Ltd.), Lipoxy VR-77, VR-60, VR-90, SP-1506, SP-1506, SP-1507, SP-1509, SP 1563 (manufactured by Showa High Polymer Co., Ltd.), NEOPOL V779, NEOPOL V779MA (manufactured by Japan U-PICA Co., Ltd.), and the like.

  Furthermore, as a trifunctional or higher functional (meth) acrylate unsaturated monomer, a trihydric or higher polyhydric alcohol (meth) acrylate such as trimethylolpropane litho (meth) acrylate, pentaerythritol tri (meth) acrylate or trimethylol. Propane trioxyethyl (meth) acrylate, tris (2-acryloyloxyethyl) isocyanurate, etc. are listed, and commercially available products include Aronix M305, M309, M310, M315, M320, M350, M360, M408 (and above, Toagosei) Made by Co., Ltd., Biscoat # 295, # 300, # 360, GPT, 3PA, # 400 (Osaka Organic Chemical Co., Ltd.), NK ester TMPT, A-TMPT, A-TMM-3, A- TMM-3L, A-TMMT (above, Shinnaka Chemical Co., Ltd.), Light Acrylate TMP-A, TMP-6EO-3A, PE-3A, PE-4A, DPE-6A (above, Kyoeisha Chemical Co., Ltd., KAYARAD PET-30, GPO-303, TMPTA) , TPA-320, DPHA, D-310, DPCA-20, DPCA-60 (manufactured by Nippon Kayaku Co., Ltd.) and the like.

  In addition, a urethane (meth) acrylate oligomer may be blended. Examples of urethane (meth) acrylates include polyether polyols such as polyethylene glycol and polytetramethyl glycol; succinic acid, adipic acid, azelaic acid, sebacic acid, phthalic acid, tetrahydro (anhydrous) phthalic acid, hexahydro (anhydrous) phthalic acid Obtained by reaction of a dibasic acid such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, etc. Polyester polyols; polyε-caprolactone-modified polyols; polymethylvalerolactone-modified polyols; ethylene glycol, propylene glycol, 1,4-butanediol, 1 Alkyl polyols such as 6-hexanediol and neopentyl glycol; bisphenol A skeleton alkylene oxide modified polyols such as ethylene oxide-added bisphenol A and propylene oxide-added bisphenol A; bisphenol F skeleton alkylene oxides such as ethylene oxide-added bisphenol F and propylene oxide-added bisphenol F Modified polyols or mixtures thereof and organic polyisocyanates such as tolylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, etc. Made from hydroxy group-containing (meth) acrylate And urethane (meth) acrylate oligomers. A urethane (meth) acrylate oligomer is preferable for maintaining the viscosity of the curable composition at an appropriate level.

  As a commercially available monomer of these urethane (meth) acrylates, for example, Aronix M120, M-150, M-156, M-215, M-220, M-225, M-240, M-245, M-270 ( As mentioned above, manufactured by Toagosei Co., Ltd.), AIB, TBA, LA, LTA, STA, Viscoat # 155, IBXA, Viscoat # 158, # 190, # 150, # 320, HEA, HPA, Viscoat # 2000, # 2100, DMA, biscort # 195, # 230, # 260, # 215, # 335HP, # 310HP, # 310HG, # 312 (above, manufactured by Osaka Organic Chemical Industry Co., Ltd.), Light Acrylate IAA, LA, SA BO-A, EC-A, MTG-A, DMP-A, THF-A, IB-XA, HOA, HOP-A, HOA-MP , HOA-MPE, light acrylate 3EG-A, 4EG-A, 9EG-A, NP-A, 1,6HX-A, DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), KAYARADTC-110S, HDDA, NPGDA , TPGDA, PEG400DA, MANDA, HX-220, HX-620 (manufactured by Nippon Kayaku Co., Ltd.), FA-511A, 512A, 513A (manufactured by Hitachi Chemical Co., Ltd.), VP (manufactured by BASF), ACMO, DMAA, DMAPAA (manufactured by Kojin Co., Ltd.) and the like.

  The urethane (meth) acrylate oligomer is obtained as a reaction product of (a) hydroxy group-containing (meth) acrylate, (b) organic polyisocyanate and (c) polyol, but (a) hydroxy group-containing (meth). A reaction product obtained by reacting an acrylate with (b) an organic polyisocyanate and then (c) a polyol is preferable.

  The above unsaturated monomers may be used alone, or a plurality of them may be mixed as necessary.

  Examples of the photo radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole. 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl)- 2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Xanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Examples thereof include bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, ethyl-2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, and the like.

  Examples of commercially available radical photopolymerization initiators include Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI 11850, CG 24-61, Darocurl 116, 1173 (above, Ciba Specialty Chemicals ( Co., Ltd.), Lucirin LR8728, 8893X (manufactured by BASF), Ubekrill P36 (manufactured by UCB), KIP150 (manufactured by Lamberti), and the like. Among these, Lucirin LR8883X is preferable from the viewpoint of being liquid and easily dissolved and having high sensitivity.

  The radical photopolymerization initiator is preferably blended in the total composition in an amount of 0.01 to 10% by weight, particularly 0.5 to 7% by weight. The upper limit of the blending amount is preferably this range from the viewpoint of the curing characteristics of the composition, the mechanical and optical properties of the cured product, the handling, etc., and the lower limit of the blending amount is preferable from the viewpoint of preventing the curing rate from being lowered.

  The composition may further contain a photosensitizer. Examples of the photosensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, 4-dimethylaminobenzoic acid. Examples thereof include methyl, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate and the like, and examples of commercially available products include Ubekryl P102, 103, 104, 105 (manufactured by UCB).

  Furthermore, in addition to the above components, various additives as necessary include, for example, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, coating surface improvers, thermal polymerization inhibitors, leveling agents, surfactants. Colorants, storage stabilizers, plasticizers, lubricants, solvents, fillers, anti-aging agents, wettability improvers, mold release agents, and the like can be blended as necessary.

  Here, examples of the antioxidant include Irganox 1010, 1035, 1076, 1222 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Antigen P, 3C, FR, GA-80 (manufactured by Sumitomo Chemical Co., Ltd.). Examples of the ultraviolet absorber include Tinuvin P, 234, 320, 326, 327, 328, 329, 213 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Seesorb 102, 103, 110, 501; 202, 712, 704 (above, manufactured by Sipro Kasei Co., Ltd.) and the like. Examples of the light stabilizer include Tinuvin 292, 144, 622LD (above, manufactured by Ciba Specialty Chemicals Co., Ltd.), Sanol LS770 ( Sankyo Co., Ltd.), Sumisorb TM-061 ( As a silane coupling agent, for example, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and a commercially available product. SH6062, 6030 (above, manufactured by Toray Dow Corning Silicone Co., Ltd.), KBE903, 603, 403 (above, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. Examples include silicone additives such as polyether and nonionic fluorosurfactants, and commercially available silicone additives include DC-57, DC-190 (above, manufactured by Dow Corning), SH-28PA, SH- 29PA, SH-30PA, SH-190 (above, Toray Dow Corning Silicone KF351, KF352, KF353, KF354 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), L-700, L-7002, L-7500, FK-024-90 (above, Nihon Unicar Co., Ltd.) ), Non-ionic fluorosurfactants commercially available as FC-430, FC-171 (above 3M), MegaFuck F-176, F-177, R-08 (above Dainippon Ink, Inc.) And a release agent such as Prisurf A208F (Daiichi Kogyo Seiyaku Co., Ltd.).

  The organic solvent for adjusting the viscosity of the resin liquid may be any organic solvent that can be mixed without unevenness such as precipitates, phase separation, and cloudiness when mixed with the above resin liquid. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone , Ethanol, propanol, butanol, 2-methoxyethanol, cyclohexanol, cyclohexane, cyclohexanone, toluene and the like, and a mixture of these may be used if necessary. . When an organic solvent is added, it is necessary to dry and evaporate the organic solvent during the product manufacturing process. However, if a large amount of residual solvent remains in the product, the mechanical properties of the product will deteriorate. There is also a concern that the organic solvent evaporates and diffuses during use as a product, causing bad odors and adverse health effects. For this reason, organic solvents having a high boiling point are not preferable because the amount of residual solvent increases. However, if the boiling point is too low, it will evaporate violently, resulting in rough surface, condensation water adhering to the surface of the composition due to the heat of vaporization during drying, resulting in surface defects and vapor concentration. It becomes higher and the risk of ignition etc. increases. Accordingly, the boiling point of the organic solvent is preferably 50 ° C. or more and 150 ° C. or less, more preferably 70 ° C. to 120 ° C. Methyl ethyl ketone (bp. 79.6 ° C.), 1-propanol (bp. 97.2 ° C.) and the like are preferable as the organic solvent from the viewpoint of the solubility of the material and the boiling point.

The amount of the organic solvent added to the resin solution depends on the type of the solvent and the viscosity of the resin solution before the addition of the solvent, but in order to sufficiently improve the coatability, it is 10 to 40% by weight. Between 15% and 30% by weight. If the amount is too small, the effect of reducing the viscosity and the effect of increasing the coating amount are small, and the coating property is not sufficiently improved. However, when the amount is too much diluted, the viscosity is too low and the liquid flows on the sheet-like body to cause unevenness, or the liquid may circulate on the back surface of the sheet-like body. In addition, the product cannot be sufficiently dried in the drying process, and a large amount of organic solvent remains in the product, resulting in deterioration of product function, volatilization during product use, generating bad odors, and adversely affecting health. The resin liquid can be produced by mixing the above-mentioned components by a conventional method, and can be produced by heating and dissolving as necessary.

  The viscosity of the resin liquid thus prepared is usually 10 to 50,000 mPa · s / 25 ° C. When supplying a resin liquid to a substrate or embossing roll, if the viscosity is too high, it will be difficult to supply the composition uniformly, and when manufacturing a lens, uneven coating, undulation, and mixing of bubbles may occur. Therefore, it becomes difficult to obtain the target lens thickness, and the lens performance cannot be fully exhibited. In particular, this tendency becomes remarkable when the line speed is increased. Accordingly, in this case, the liquid viscosity is preferably low, 10 to 100 mPa · s, and more preferably 10 to 50 mPa · s. Such a low viscosity can be adjusted by adding an appropriate amount of the organic solvent. It is also possible to adjust the viscosity by setting the heat retention of the coating solution. On the other hand, if the viscosity after evaporation of the solvent is too low, it may be difficult to control the lens thickness when embossing the mold, and a uniform lens with a constant thickness may not be formed. The preferred viscosity is 100 to 3,000 mPa · s. It is. When an organic solvent is mixed, a low viscosity is provided when the resin liquid is supplied by providing a process for evaporating the organic solvent by heat drying, etc., between the process of supplying the resin liquid and embossing with the embossing roll. Thus, when the embossing roll is used for embossing, the embossing roll can be uniformly embossed with a resin liquid obtained by drying the organic solvent and increasing the viscosity.

  Next, a preferred example when a prism sheet is manufactured as an optical sheet will be described.

  It is particularly preferable that the cured product obtained by curing the resin liquid with radiation has the following physical properties. The refractive index of the cured product at 25 ° C. is preferably 1.55 or more, and more preferably 1.56 or more. When the refractive index is less than 1.55, when a prism lens sheet is formed using this composition, sufficient front luminance may not be ensured.

  Furthermore, the softening point of the cured product is preferably 40 ° C. or higher, particularly 50 ° C. or higher. When the softening point is less than 40 ° C., the heat resistance may not be sufficient.

  As described above, according to this embodiment, the nip pressure P and the resin viscosity η with respect to the resin coating sheet S by the embossing roll 13 and the nip roll 14 are adjusted to appropriate values, and the embossing roll 13 is compared with the resin layer F. To be pressed appropriately. Accordingly, it is possible to appropriately prevent air from being mixed into the resin layer F between the embossing roll 13 and the nip roll 14 and to prevent the embossing roll 13 and the nip roll 14 from being excessively pressed against the resin layer F. An embossed sheet (optical sheet) is manufactured. In particular, the resin layer F is defective between the embossing roll 13 and the nip roll 14 as in the case where an optical sheet having a relatively large width is manufactured or the sheet conveying speed is increased in order to increase the manufacturing speed of the optical sheet. Even if it is easy to generate | occur | produce, according to the above-mentioned method which concerns on this embodiment, a desired emboss sheet (optical sheet) can be manufactured with sufficient quality.

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

  For example, in the above-described embodiment, the example in which the resin layer F is directly formed on the web W has been described. However, the present invention is not limited to this. For example, as shown in FIG. 6, an adhesive layer B may be provided between the web W and the resin layer F to improve the adhesion between the web W and the resin layer F. In this case, the adhesive layer B may be formed in advance on the web W, or the adhesive layer B may be applied to the web W immediately before the resin layer F is applied to the web W.

  Next, specific examples based on the present invention will be described. In addition, the following examples are illustrations and do not limit the present invention.

Example 1
In this example, the prism sheet was manufactured by the embossed sheet manufacturing apparatus 10 shown in FIG.

  As the web W, a PET (polyethylene terephthalate) film having a width of 400 mm and a thickness of 175 μm was used.

  The conveyance speed (line speed) of the web W and the resin coated sheet S was adjusted to 5 m / min.

  As the embossing roll 13, a roll having a diameter of 350 mm and a width of 400 mm was used. Specifically, an iron roll was subjected to copper plating, a prism shape was processed on the copper plating portion, and a hard chrome plating was further used as the embossing roll 13.

  The predetermined uneven pattern formed on the embossing roll 13 has a pattern shape such that the prism transferred to the resin layer L by the embossing roll 13 has a shape with an apex angle of 90 °, a height of 25 μm, and a width of 50 μm. It has become.

  As the nip roll 14, a hard rubber roll having a diameter of 70 mm and a width of 400 mm was used. The variation in the diameter of the nip roll 14 was 50 μm or less.

  As the application unit 12, a Barco overnight application device was used.

  A resin containing an acrylic UV curable resin was used as the resin applied on the web W by the application unit 12.

  FIG. 7 shows the surface shape of the resin layer F (see “surface shape” in the figure) in Example 1 in which the fine unevenness pattern was formed by the embossing roll 13. In particular, the embossing roll 13 under the above conditions. 2 shows the surface shape of the resin layer F when the nip pressure P (MPa) on the resin-coated sheet S by the nip roll 14 and the viscosity η (mPa · s) of the resin constituting the resin layer F are changed. The surface shape of the resin layer F was determined by visual observation. Further, “Remarks” in FIG. 7 mainly describes the surface shape of the resin layer F.

(Example 2)
Also in this example, the prism sheet was manufactured by the embossed sheet manufacturing apparatus 10 shown in FIG. Detailed description of the same conditions as those in the first embodiment will be omitted.

  In this example, a hard rubber roll having a diameter of 70 mm and a width of 400 mm was used as the nip roll 14. The variation in the diameter of the nip roll 14 was 100 μm or less.

  FIG. 8 shows the surface shape of the resin layer F in Example 2 in which the fine uneven pattern is formed by the embossing roll 13 (see “surface shape” in the drawing). In particular, the embossing roll 13 under the above conditions. 2 shows the surface shape of the resin layer F when the nip pressure P (MPa) on the resin-coated sheet S by the nip roll 14 and the viscosity η (mPa · s) of the resin constituting the resin layer F are changed.

(Consideration of each example)
From the result of the surface shape of the resin layer F of the result of Example 1 (see FIG. 7), the nip pressure P (MPa) applied to the resin coated sheet S by the embossing roll 13 and the nip roll 14, and the resin constituting the resin layer F It can be seen that it is preferable to adjust the viscosity η (mPa · s) so that the above formula (1) is satisfied.

  Further, comparing the results of Examples 1 and 2 described above (see FIGS. 7 and 8), it can be seen that at least the variation in the diameter of the nip roll (entrance roll) 14 is preferably 50 μm or less.

It is a conceptual diagram which shows the structure of the manufacturing apparatus of an embossed sheet. It is sectional drawing which shows the arrangement | positioning relationship of a web and a resin layer. It is a figure which shows the outline of the cross section of an embossing roll. It is a figure which shows the relationship between the nip pressure (vertical axis) applied with respect to a resin application sheet with an embossing roll and a nip roll, and the viscosity (horizontal axis) of UV curable resin which comprises a resin layer. It is a perspective view which shows the structure of a nip roll. It is sectional drawing which shows the modification of the arrangement | positioning relationship of a web and a resin layer. The surface shape of the resin layer in Example 1 in which the fine uneven | corrugated pattern was formed with the embossing roll is shown. The surface shape of the resin layer in Example 2 in which the fine uneven | corrugated pattern was formed with the embossing roll is shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Embossed sheet manufacturing apparatus, 11 ... Web supply part, 12 ... Application | coating part, 13 ... Embossing roll, 14 ... Nip roll, 15 ... Resin hardening part, 16 ... Peeling roll, 17 ... Protection film supply part, 18 ... Sheet winding Take part, W ... web, F ... resin layer

Claims (6)

An optical for producing an optical sheet by nipping a support coated with an optical member between a pattern roll and an entrance roll and winding the support on the pattern roll to transfer a predetermined pattern formed on the pattern roll to the optical member. A sheet manufacturing method comprising:
The nip pressure P (MPa) against the support by the pattern roll and the inlet roll, and the viscosity η (mPa · s) of the optical member,
(1/2) × log ₁₀ η−3 ≦ log ₁₀ P ≦ (1/2) × log ₁₀ η−2
(1 ≦ η ≦ 10000)
An optical sheet manufacturing method characterized in that the optical sheet is set so as to satisfy the relationship. The viscosity η (mPa · s) of the optical member is
10 ≦ η ≦ 1000
The method for producing an optical sheet according to claim 1, wherein:   The method for producing an optical sheet according to claim 1, wherein a variation in distance between the pattern roll and the entrance roll is 50 μm or less.   The method for producing an optical sheet according to any one of claims 1 to 3, wherein a variation in diameter of the entrance roll is 50 m or less.   The optical sheet manufactured by the manufacturing method of the optical sheet of any one of Claims 1 thru | or 4. An optical sheet manufacturing apparatus for manufacturing an optical sheet,
A pattern roll having a predetermined pattern;
An entrance roll that sandwiches the support coated with the optical member together with the pattern roll and transfers a predetermined pattern of the pattern roll to the optical member, and
The nip pressure P (MPa) against the support by the pattern roll and the inlet roll, and the viscosity η (mPa · s) of the optical member,
(1/2) × log ₁₀ η−3 ≦ log ₁₀ P ≦ (1/2) × log ₁₀ η−2
(1 ≦ η ≦ 10000)
The optical sheet manufacturing apparatus is characterized by being set to satisfy the relationship.

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