JP2002372632A - Light guide plate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide plate and a method for manufacturing the plate having preferable heat resistance, water proofing property, transparency and secondary processing property and improved optical strain. SOLUTION: The light guide plate is manufactured by forming a molding material containing a norbornene thermoplastic resin by a melt extrusion or solution flow cast method into a sheet and then forming recesses and projections having functions to reflect and/or refract light on at least one surface of the sheet. The method for manufacturing the plate includes the above steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate for a liquid crystal display and, more particularly, to reflect and / or refract light on at least one surface of a melt-extruded sheet of a norbornene-based thermoplastic resin or a sheet formed by a solution casting method. Heat resistance, obtained by forming irregularities having a function,
The present invention relates to a light guide plate for a liquid crystal display having high brightness, secondary workability, and low optical distortion, particularly to a light guide plate for a front light and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as a display section of a portable information terminal such as a personal display adapter or a portable telephone has become colorized, a reflection type color liquid crystal has been utilized by taking advantage of its clarity and low power consumption. A display device is employed. Such a reflection type color liquid crystal display device often uses an illumination device called a front light in order to be usable even in darkness. For this front light, a light guide plate is used as in the case of a conventionally used backlight. For the light guide plate for the front light, methacrylic resin that has been used as the light guide plate for the backlight conventionally,
Alternatively, a polycarbonate resin is employed. However, methacrylic resin has a limitation in heat resistance, and thus has a problem of deformation in a use environment or a problem of restriction on secondary processing conditions such as antireflection processing. Polycarbonate resins are excellent in heat resistance, but have problems in hue and birefringence, and have problems in use in color liquid crystals. Further, the light guide plate is usually manufactured by injection molding, but there is a problem that optical distortion due to the flow of resin during injection molding remains. On the other hand, the norbornene-based thermoplastic resin is excellent in heat resistance and also in optical distortion and hue. Therefore, taking advantage of these characteristics, it is being adopted as a front light guide plate. However, the light guide plate is usually manufactured by injection molding. However, since optical distortion remains due to the flow during injection molding, there is a problem in its use in applications where these requirements are severe.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and has as its object the problem that the conventional light guide plate made of a norbornene-based thermoplastic resin has good heat resistance. An object of the present invention is to provide a light guide plate having improved optical distortion while maintaining the properties, water resistance, transparency, and secondary workability, and a method for manufacturing the same.

[0004]

According to the present invention, as a means for solving the above problems, at least one sheet obtained by molding a molding material containing a norbornene-based thermoplastic resin by melt extrusion molding or solution casting is used. Reflect light on the surface and / or
Alternatively, a light guide plate provided with unevenness having a function of refraction is provided. Further, the present invention has a function of forming a molding material containing a norbornene-based thermoplastic resin into a sheet by melt extrusion molding or solution casting, and reflecting and / or refracting light on at least one surface of the obtained sheet. The method for manufacturing a light guide plate is provided, wherein the unevenness is transferred from a mold.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION <Molding material><Norbornene-based thermoplastic resin> Examples of the norbornene-based thermoplastic resin used in the present invention include the following polymers. Hereinafter, the homopolymer and the copolymer are collectively referred to as “(co) polymer”. A ring-opened homopolymer of a monomer represented by the following general formula (I) (hereinafter, referred to as “specific monomer”). A ring-opening copolymer of a specific monomer and another ring-opening copolymerizable monomer. A hydrogenated (co) polymer of the above ring-opened (co) polymer. A hydrogenated (co) polymer obtained by cyclizing the above-mentioned ring-opened (co) polymer by Friedel-Crafts reaction. A saturated copolymer of a specific monomer and another compound containing a polymerizable unsaturated double bond.

[0006]

Embedded image

[Wherein, R1 to R4 independently represent a hydrogen atom,
A halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or another monovalent organic group, which may be the same or different. R1 and R2 or R3 and R4
May combine to form a divalent hydrocarbon group;
1 or R2 and R3 or R4 may combine with each other to form a monocyclic or polycyclic structure. m is 0 or a positive integer, and p is 0 or a positive integer. However, when m is 0, p is also 0. ]

<Ring-opened (co) polymer> Specific monomer: As a preferable specific monomer, in the above formula (I), R1 and R3 are each a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. R2 and R4 are a hydrogen atom or a monovalent organic group, at least one of R2 and R4 represents a polar group other than a hydrogen atom and a hydrocarbon group, m is an integer of 0 to 3, and p is An integer from 0 to 3;
+ P is 0 to 4, preferably 0 to 2, particularly preferably 1. In particular, among the specific monomers, formula (II): — (CH ₂ ) _n COOR ⁵ (II) wherein R 5 has 1 to 12 carbon atoms, and n is usually 0
Is an integer of up to 5. Is preferable since the norbornene-based thermoplastic resin obtained has a high glass transition temperature and a low hygroscopicity. In the above formula (II), R5 has 1 to 1 carbon atoms.
Two hydrocarbon groups, for example, methyl, ethyl, propyl,
Isopropyl, butyl, sec-butyl, t-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl, cyclooctyl, phenyl, naphthyl and the like are preferable, and methyl and ethyl are preferable. In addition, n is usually 0 to 5, but a smaller value of n is preferable because the glass transition temperature of the obtained norbornene-based thermoplastic resin becomes higher.
Is preferred in that its synthesis is easy. Further, in the general formula (I), R1 or R3
Is preferably an alkyl group, and the alkyl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1. In particular, it is preferable that this alkyl group is bonded to the same carbon atom as the carbon atom to which the polar group represented by the above formula (II) is bonded. Further, the specific monomer in which m is 1 in the general formula (I) is preferable in that a norbornene-based thermoplastic resin having a high glass transition temperature can be obtained.

Specific examples of the specific monomer represented by the above general formula (I) include the following compounds. Bicyclo [2.2.1] hept-2-ene, tricyclo [5.2.1.02,6] -8-decene, tetracyclo [4.4.0.12, 5.17,10] -3- Dodecene, pentacyclo [6.5.1.13, 6.02,7.
09,13] -4-pentadecene,

Pentacyclo [7.4.0.12,5.1
9,12.08,13] -3-pentadecene, tricyclo [4.4.0.12,5] -3-undecene, 5-methylbicyclo [2.2.1] hept-2-ene, 5-ethyl Bicyclo [2.2.1] hept-2-ene, 5-methoxycarbonylbicyclo [2.2.1] hept-2-
Ene, 5-methyl-5-methoxycarbonylbicyclo [2.2.1] hept-2-ene, 5-cyanobicyclo [2.2.1] hept-2-ene, 8-methoxycarbonyltetracyclo [4. 4.0.12, 5.17, 1
0] -3-dodecene,

8-ethoxycarbonyltetracyclo [4.4.0.12,5.17,10] -3-dodecene, 8-n-propoxycarbonyltetracyclo [4.
4.0.12, 5.17, 10] -3-dodecene, 8-
Isopropoxycarbonyltetracyclo [4.4.0.
12,5.17,10] -3-dodecene, 8-n-butoxycarbonyltetracyclo [4.4.0.12,5.
17,10] -3-dodecene, 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.12,5.1
7,10] -3-dodecene,

8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.12,5.17,10] -3-
Dodecene, 8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.12, 5.17,10]-
3-dodecene, 8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.12, 5.17,1
0] -3-dodecene, 8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.12, 5.17,
10] -3-dodecene,

Dimethanooctahydronaphthalene, ethyltetracyclododecene, 6-ethylidene-2-tetracyclododecene, trimethanooctahydronaphthalene,
Pentacyclo [8.4.0.12, 5.19, 12.0
8,13] -3-hexadecene, heptacyclo [8.
7.0.13, 6.110, 17.112, 15.0
2,7.011,16] -4-eicosene,

Heptacyclo [8.8.0.14,7.1
11, 18.113, 16.03, 8.012, 17]
-5-heneicosene, 5-ethylidenebicyclo [2.
2.1] Hept-2-ene, 8-ethylidenetetracyclo [4.4.0.12, 5.17,10] -3-dodecene, 5-phenylbicyclo [2.2.1] hept-2-
En,

8-phenyltetracyclo [4.4.0.
12,5.17,10] -3-dodecene, 5-fluorobicyclo [2.2.1] hept-2-ene, 5-fluoromethylbicyclo [2.2.1] hept-2-ene, 5
-Trifluoromethylbicyclo [2.2.1] hept-
2-ene, 5-pentafluoroethylbicyclo [2.
2.1] Hept-2-ene, 5,5-difluorobicyclo [2.2.1] hept-2-ene, 5,6-difluorobicyclo [2.2.1] hept-2-ene, 5, 5-
Bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene, 5-methyl-5
-Trifluoromethylbicyclo [2.2.1] hept-
2-ene, 5,5,6-trifluorobicyclo [2.
2.1] Hept-2-ene, 5,5,6-tris (fluoromethyl) bicyclo [2.2.1] hept-2-ene, 5,5,6,6-tetrafluorobicyclo [2.
2.1] Hept-2-ene, 5,5,6,6-tetrakis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,

5,5-difluoro-6,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-
Ene, 5,6-difluoro-5,6-bis (trifluoromethyl) bicyclo [2.2.1] hept-2-ene,
5,5,6-trifluoro-5-trifluoromethylbicyclo [2.2.1] hept-2-ene, 5-fluoro-5-pentafluoroethyl-6,6-bis (trifluoromethyl) bicyclo [ 2.2.1] Hept-2-ene, 5,6-difluoro-5-heptafluoro-iso
-Propyl-6-trifluoromethylbicyclo [2.
2.1] hept-2-ene,

5-chloro-5,6,6-trifluorobicyclo [2.2.1] hept-2-ene, 5,6-dichloro-5,6-bis (trifluoromethyl) bicyclo [2.2 .1] hept-2-ene, 5,5,6-trifluoro-6-trifluoromethoxybicyclo [2.2.
1] hept-2-ene,

5,5,6-trifluoro-6-heptafluoropropoxybicyclo [2.2.1] hept-2-
Ene, 8-fluorotetracyclo [4.4.0.12,
5.17,10] -3-dodecene, 8-fluoromethyltetracyclo [4.4.0.12, 5.17,10]-
3-dodecene, 8-difluoromethyltetracyclo [4.4.0.12,5.17,10] -3-dodecene,

8-trifluoromethyltetracyclo [4.4.0.12,5.17,10] -3-dodecene, 8-pentafluoroethyltetracyclo [4.4.
0.12, 5.17, 10] -3-dodecene, 8, 8-
Difluorotetracyclo [4.4.0.12,5.1
7,10] -3-dodecene, 8,9-difluorotetracyclo [4.4.0.12,5.17,10] -3-dodecene,

8,8-bis (trifluoromethyl) tetracyclo [4.4.0.12,5.17,10] -3-
Dodecene, 8,9-bis (trifluoromethyl) tetracyclo [4.4.0.12,5.17,10] -3-dodecene, 8-methyl-8-trifluoromethyltetracyclo [4.4.0] .12, 5.17, 10] -3-dodecene, 8,8,9-trifluorotetracyclo [4.
4.0.12, 5.17, 10] -3-dodecene, 8,
8,9-tris (trifluoromethyl) tetracyclo [4.4.0.12,5.17,10] -3-dodecene;

8,8,9,9-tetrafluorotetracyclo [4.4.0.12,5.17,10] -3-dodecene, 8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.12, 5.17,1
0] -3-dodecene, 8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.
12,5.17,10] -3-dodecene, 8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.12,5.17,10] -3-dodecene; 8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.12,5.17,1
0] -3-dodecene,

8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.12,5.1
7,10] -3-dodecene, 8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.
4.0.12, 5.17, 10] -3-dodecene, 8-
Fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1
2,5.17,10] -3-dodecene, 8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.12,5.
17,10] -3-dodecene, 8-chloro-8,9,9
-Trifluorotetracyclo [4.4.0.12,5.
17,10] -3-dodecene,

8,9-Dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.12,5.
17,10] -3-dodecene, 8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.
0.12,5.17,10] -3-dodecene, 8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.12,5.17,1
0] -3-dodecene and the like. These specific monomers may be used alone or in combination of two or more.

Among these specific monomers, 8-methyl-
8-methoxycarbonyltetracyclo [4.4.0.1
2,5.17,10] -3-dodecene, 8-ethylidenetetracyclo [4.4.0.12,5.17,10]-
3-dodecene, 8-ethyltetracyclo [4.4.0.
12,5.17,10] -3-dodecene, pentacyclo [7.4.0.12,5.19,12.08,13]-
3-Pentadecene is preferable in that the finally obtained norbornene-based thermoplastic resin has excellent heat resistance, and particularly preferable is 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.12. , 5.17,1
0] -3-dodecene.

Other copolymerizable ring-opening monomer: In the ring-opening polymerization step for obtaining the norbornene-based thermoplastic resin of the present invention, the above-mentioned specific monomer may be subjected to ring-opening polymerization alone. The ring-opening copolymer can also be obtained by subjecting the specific monomer and the copolymerizable monomer to ring-opening polymerization. Specific examples of the copolymerizable monomer used in this case include cyclobutene,
Cyclopentene, cycloheptene, cyclooctene, tricyclo [5.2.1.02,6] -3-decene, 5-
Examples thereof include cycloolefins such as ethylidene-2-norbornene and dicyclopentadiene. The number of carbon atoms in the cycloolefin is preferably from 4 to 20, and more preferably from 5 to 12. Specified in the presence of unsaturated hydrocarbon-based polymers containing a carbon-carbon double bond in the main chain, such as polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-nonconjugated diene copolymer, and polynorbornene The monomer may be subjected to ring-opening polymerization. The hydrogenated ring-opening (co) polymer obtained in this case is useful as a raw material for a resin having high impact resistance.

Ring-opening polymerization catalyst: A ring-opening polymerization reaction of a specific monomer or a specific monomer and another ring-opening polymerizable monomer is carried out in the presence of a metathesis catalyst. This metathesis catalyst comprises (a) at least one selected from compounds of W, Mo, and Re; (b) a group IA element (eg, Li, Na, K, etc.) of the Deming periodic table; and a group IIA element (eg, M
g, Ca, etc.), Group IIB elements (eg, Zn, Cd, Hg)
A group IIIB element (eg, B, Al, etc.), a group IVA element (eg, Ti, Zr, etc.) or a compound of a group IVB element (eg, Si, Sn, Pb, etc.) A catalyst comprising a combination of at least one selected from those having a bond or the element-hydrogen bond. In this case, in order to increase the activity of the catalyst, an additive (c) described below may be added.

Representative examples of W, Mo or Re compounds suitable as component (a) include WCl6, MoCl
5, compounds such as ReOCl3 described in JP-A-1-240517. Specific examples of the component (b) include n-C4H9Li, (C
2H5) 3Al, (C2H5) 2AlCl, (C2H
5) 1.5AlCl1.5, (C2H5) AlCl2,
JP-A-1-24051 such as methylalumoxane and LiH
No. 7 can be mentioned. Representative examples of the above additive (c) include alcohols,
Aldehydes, ketones, amines and the like can be preferably used, and further, compounds described in JP-A-1-240517 can be used.

The amount of the metathesis catalyst used is such that the molar ratio of the component (a) to the specific monomer is such that "component (a): specific monomer" is usually 1: 500 to 1: 50000. , Preferably in the range of 1: 1000 to 1: 10000. The ratio of the component (a) to the component (b) is such that “(a) :( b)” is in the range of 1: 1 to 1:50, preferably 1: 2 to 1:30 in terms of metal atom ratio. . The ratio of the component (a) to the component (c) is “(c) :( a)” in molar ratio.
Is 0.005: 1 to 15: 1, preferably 0.05: 1
７7: 1.

Molecular weight regulator: The molecular weight of the ring-opened polymer can be controlled by the polymerization temperature, the type of catalyst, and the type of solvent. In the present invention, the molecular weight regulator is prepared by coexisting in the reaction system. Adjustment is preferred. Here, preferred molecular weight regulators include, for example, ethylene,
Propene, 1-butene, 1-pentene, 1-hexene,
Examples thereof include α-olefins such as 1-heptene, 1-octene, 1-nonene, and 1-decene, and styrene, of which 1-butene and 1-hexene are particularly preferable. These molecular weight regulators can be used alone or
A mixture of more than one species can be used. The amount of the molecular weight modifier used may be the specific monomer 1 to be subjected to the ring-opening polymerization reaction.
0.005 to 0.6 mol, preferably 0.1 to 0.5 mol per mol.
02 to 0.5 mol.

Solvent for ring-opening polymerization reaction: Examples of the solvent (solvent for dissolving the specific monomer, the metathesis catalyst and the molecular weight modifier) used in the ring-opening polymerization reaction include, for example, pentane, hexane, heptane, octane, nonane, decane Alkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; chlorobutane, bromohexane, methylene chloride, dichloroethane, hexamethylene Dibromide, chlorobenzene, chloroform,
Halogenated alkanes such as tetrachloroethylene; compounds such as aryl; saturated carboxylic esters such as ethyl acetate, n-butyl acetate, iso-butyl acetate, methyl propionate and dimethoxyethane; ethers such as dibutyl ether, tetrahydrofuran and dimethoxyethane These can be used alone or as a mixture. Of these, aromatic hydrocarbons are preferred. The amount of the solvent used is such that “solvent: specific monomer (weight ratio)” is usually 1: 1 to 10: 1, preferably 1: 1 to 5: 1. .

<Hydrogenated (co) polymer> The above-mentioned ring-opened (co) polymer can be used as it is as a norbornene-based thermoplastic resin in the light guide plate of the present invention. ) It is more preferably used as a polymer. The hydrogenation reaction is carried out in a usual manner, that is, a hydrogenation catalyst is added to a solution of the ring-opening (co) polymer, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm is added at 0 to 200 ° C. , Preferably at 20 to 180 ° C. As the hydrogenation catalyst, those used in ordinary hydrogenation reactions of olefinic compounds can be used. As this hydrogenation catalyst,
Heterogeneous and homogeneous catalysts are known. Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst substance such as palladium, platinum, nickel, rhodium and ruthenium is supported on a carrier such as carbon, silica, alumina and titania. Further, as a homogeneous catalyst, nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride,
Rhodium acetate, chlorotris (triphenylphosphine) rhodium, dichlorotris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorocarbonyltris (triphenylphosphine) ruthenium and the like can be mentioned. The form of the catalyst may be powdery or granular. These hydrogenation catalysts have a “ring-opening (co) polymer: hydrogenation catalyst (weight ratio)” of 1: 1 × 10 −6 to 1: 2.
It is used at a ratio of As described above, the hydrogenated (co) polymer obtained by hydrogenation has excellent thermal stability, and its properties are not deteriorated by heating during molding or use as a product. . Here, the hydrogenation rate is usually 50% or more, preferably 70%
Above, more preferably 90% or more.

<Saturated copolymer> The saturated copolymer is obtained by subjecting a specific monomer and a compound having a copolymerizable unsaturated double bond to a copolymerization reaction. Examples of the unsaturated double bond-containing compound include olefin compounds having 2 to 12 carbon atoms, preferably 2 to 8 carbon atoms, such as ethylene, propylene, and butene.

Polymerization catalyst: As the catalyst used for the copolymerization reaction between the specific monomer and the unsaturated double bond-containing compound, a catalyst comprising a vanadium compound and an organoaluminum compound is used. The vanadium compound is represented by the general formula V
O (OR) aXb or V (OR) cXd (where R
Is a hydrocarbon group, 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ a + b ≦
3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, 3 ≦ c + d ≦ 4) vanadium compounds, or adducts of these electron donors are used. Examples of electron donors include alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic or inorganic acids, ethers, acid amides, acid anhydrides, oxygen-containing electron donors such as alkoxysilanes, ammonia, amines, nitriles, Examples include nitrogen-containing electron donors such as isocyanates. As the organoaluminum compound catalyst component, at least one selected from those having at least one aluminum-carbon bond or aluminum-hydrogen bond is used. The ratio of the catalyst component is the ratio of aluminum to vanadium (Al /
V) is 2 or more, preferably 2 to 50, particularly preferably 3
-20.

Reaction solvent: The above copolymerization reaction is usually carried out in a solvent. As the solvent used, for example, alkanes such as pentane, hexane, heptane, octane, nonane, decane, cycloalkanes such as cyclohexane and methylcyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, and halogen derivatives thereof. Among them, cyclohexane is preferable.

<Conditions of Resin> The intrinsic viscosity (ηinh) of the norbornene-based thermoplastic resin used in the present invention measured in chloroform at 30 ° C. is preferably 0.2 to 5 dl / g, and more preferably. 0.3-4.
As the molecular weight, the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 8,000 to 100,000,
Weight average molecular weight (Mw) of 20,000 to 300,00
Those in the range of 0 are preferred.

It is preferable that the norbornene-based thermoplastic resin used in the present invention has little foreign matter causing visual defects and abnormal bright spots when it is used as an optical material, and it is preferably present as little as possible. The content of such foreign matters is at least 5
It is preferable that the number of foreign particles having a particle size of 0 μm or more is 0/10 g, preferably the number of foreign particles having a particle size of 30 μm or more is 0/10 g, and particularly preferably the number of foreign particles having a particle size of 20 μm or more is 0/10 g. The amount of foreign matter is measured by dissolving the resin in a solvent such as toluene or cyclohexane, which has solubility for the resin used in the molded article, filtering the mixture through a filter, and observing it with a microscope to count the size and number. Will be Similarly, foreign particles in a solvent in which a resin is dissolved can be counted using a commercially available fine particle counter based on light scattering.

<Other Components> In addition to the norbornene-based thermoplastic resin, which is an essential component, the molding material used in the present invention may be, if necessary, known in a range that does not impair the transparency and heat resistance of the molded product. Thermoplastic resins, thermoplastic elastomers, rubbery polymers, organic fine particles, inorganic fine particles, dyes,
A pigment, a hydrocarbon-based low molecular resin, or the like may be blended. Further, a known antioxidant, for example, 2, 6
-Di-t-butyl-4-methylphenol, 2,2'-
Dioxy-3,3'-di-t-butyl-5,5'-dimethyldiphenylmethane, tetrakis [methylene-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate] methane; UV absorber, for example, 2,4
-Dihydroxybenzophenone, 2-hydroxy-4-
Stability can be increased by adding methoxybenzophenone, benzylidene malonate ester compound, or the like. Further, an additive such as a lubricant may be added for the purpose of improving workability.

--Method of Manufacturing Light Guide Plate-- The light guide plate of the present invention is obtained by first molding the above molding material into a sheet (flat plate) by a known melt extrusion method or solution casting method, and then reflecting light. It can be manufactured by forming irregularities having a function of refraction and / or refraction on the surface. Flat plate obtained by melt extrusion method or solution casting method,
When the light guide plate has a small optical distortion in the plane, the display unit has an excellent image quality.

Here, the melt extrusion method means that a thin melt is extruded from a film or sheet die attached to the tip of an extruder, and cooled or solidified by various rolls or belts to obtain a film or sheet. Is the way. The extruder used for the melt extrusion method is not particularly limited, and a known extruder can be used. Usually, a single-screw or twin-screw extruder is used, and a single-screw extruder is preferably used. The cylinder diameter of the extruder is usually 10 to 100 mm. Known screws are used as the screws. For example, in the case of a single shaft, a combination of a full flight and a subflight, a combination of a dalmage, and a screw in which the screw pitch or groove depth changes in the same screw can be mentioned. In the case of a twin screw, two or three screws,
In the case of different directions or co-rotation, and the method of freely combining screw parts, it is possible to freely select and incorporate the shape of screw parts from screw type, reverse feed screw, paddle type screw, helical paddle type screw etc. is there. Although one extruder can be operated, a combination of two or more extruders or a combination of a continuous type and a batch type kneader may be used.

The solution casting method is a method in which a molding material is dissolved in a solvent in which the molding material is soluble, the solution is cast into a sheet, and the solvent is separated by a known method.
For example, it can be manufactured by a method disclosed in JP-A-5-148413. Examples of the solvent used in the solution casting method include aromatic compounds such as benzene, toluene, and xylene, butyl acetate, tetrahydrofurandimethoxyethane, chloroform, methylene dichloride, and methyl ethyl ketone. As a method of performing the solution casting, the solution is extruded from a die having a constant width onto a metal drum, a steel belt, a polyester film, a Teflon (registered trademark) belt, or the like, and dried over a temperature and time. In addition, a sheet having a desired thickness can be produced by applying a solution by spraying, brushing, rolling, spin coating, dipping, or the like, and arbitrarily applying temperature and time.

The sheet produced by any of the above-mentioned methods usually has a long shape with a uniform thickness. For example, the shape of the die is tapered and the thickness is inclined. It may have a certain shape.

The sheet obtained by the above method may be used as it is in the form of a long sheet for secondary processing such as surface shaping, hard coating or anti-reflection processing, or may be cut to a desired size to obtain a sheet. It may be used for the next processing. As a method of cutting, a method of cutting with a mechanical cutter with a metal blade or a diamond blade, a melt cutting method using a blade or a wire heated above the melting point of the norbornene-based thermoplastic resin, an ultrasonic wave was used. cutter,
A known method of cutting using a laser beam, a method of applying water or fine particles of metal or the like to water at a high pressure, and cutting the material can be used. The end surface of the cut sheet can be smoothed by a known method such as polishing or hot melting.

A sheet cut to a desired size is usually provided on its surface with irregularities having a function of reflecting and / or refracting light, for example, JP-A-5-341133, JP-A-5-341133.
-250715, JP-A-2000-347041, JP-A-2
000-314882, a prism or a dot pattern as disclosed in JP-A-2001-35227 is formed, but the light incident on the light guide plate is efficiently emitted without causing obstacles such as interference, and the like. The shape is not particularly limited as long as it has a shape capable of emitting more light.

Such unevenness is formed by a known method.
Hereinafter, a method for forming the irregularities will be exemplified, but the method is not particularly limited. Tg to Tg + 80 ° C., preferably Tg + 10 ° C. to T, based on the glass transition temperature Tg of the cyclic olefin resin.
A method in which a sheet is pressed against a mold or a stamper heated to a temperature of g + 40 ° C. to form irregularities. A heat or ultraviolet curable liquid resin (composition), for example, a known organic compound (composition) such as acrylic, epoxy, or norbornene is applied to the surface of the sheet,
Thereafter, a mold is pressed, and then the liquid resin (composition) is cured or dried by a known method such as heat or light to form irregularities. In the case where the sheet is prepared by a melt extrusion method, the sheet is preliminarily shaped and transferred onto a roll or a metal belt for cooling and solidifying the sheet. When prepared by the solution casting method, a method of imparting a shape in advance to a drum or a metal belt on which the solution of the cyclic olefin-based resin of the present invention is cast, and transferring the solution. A method in which a groove shape is provided in advance to a sheet die of a melt extrusion method or a solution casting method, and a groove-shaped pattern is formed on the sheet surface. A method of forming a concavo-convex pattern by cutting the sheet surface by a known method or etching it with a laser or the like. And so on.

Further, a film, sheet or molded plate having irregularities having a function of reflecting and / or refracting light by a known method may be laminated on the surface of the sheet of the present invention. The film, sheet or molded plate to be laminated is
Although it is preferable to use the norbornene-based thermoplastic resin used in the present invention from the viewpoint of heat resistance and the like, a methacrylic resin or a polycarbonate may be used,
It is also possible to use a methacrylic transparent resin obtained by a cast polymerization method. As the bonding method at the time of laminating, for example, a method using a known thermosetting or UV-curing adhesive or the like, a method of fusing with heat, ultrasonic waves, high frequency, or the like can be used. .

The light guide plate of the present invention can be subjected to antireflection processing by a known method. In particular, when a front light guide plate is used, it is preferable to perform anti-reflection processing. For the antireflection processing of the light guide plate, known dry or wet methods can be used. For the dry type anti-reflection processing, for example, a method of coating an inorganic compound on the surface of a norbornene-based resin disclosed in JP-A-4-89821 and JP-A-9-120001 can be adopted. As the inorganic compound used for the antireflection processing, known oxides such as silicon, titanium, germanium, aluminum, tantalum, and zirconium, nitrides, and fluorides are used. The method of vacuum deposition is not particularly limited, but a known technique of PVD or CVD is used. In addition, even if one coating layer
It may have a multilayer structure of more than two layers. Although the thickness per layer is not particularly limited, it is usually laminated in a range of 10 nm to 500 nm. Wet anti-reflection processing is described in, for example,
A known organic compound as disclosed in Japanese Patent Publication No.
It is performed by applying to the front light surface by a method such as brush coating, roll coating, dipping, spin coating, or spraying.

In the present invention, for efficient antireflection, the refractive index of the organic compound used is preferably 1.45 or less. For example, vinylidene fluoride / hexafluoropropylene polymer, tetrafluoroethylene /
A vinylidene fluoride / hexafluoropropylene terpolymer, a perfluoroalkyl ether copolymer, a fluorinated methacrylate polymer, or the like can be used.
These organic substances can be cured by a method such as thermal curing, UV curing, or electron beam curing. These antireflection treatments may be a single or multilayer inorganic coat layer, a single or multilayer organic coat layer, or a combination of an inorganic coat and an organic coat. The antireflection treatment is preferable because the cycloolefin resin or the cyclic olefin resin composition used in the present invention can be processed without any particular pretreatment when it contains one or more polar groups. When a polar group is not contained, it is preferable to perform pretreatment such as chromic anhydride-acetic acid, chloric acid-sulfuric acid, and dichromic acid-sulfuric acid.

The light guide plate of the present invention is useful for front lights and backlights. In addition, a known component, for example, a light source such as a cold-cathode tube, an LED, and a light guide, a polarizing plate, a diffusion plate, a reflection plate, a touch panel, a protection plate, and the like are combined as necessary to mainly provide an illumination unit for a liquid crystal display device Assembled as

The light guide plate of the present invention preferably has a small in-plane birefringence, that is, a small phase difference, and a small in-plane phase difference deviation. The in-plane retardation is preferably 3
It is 0 nm or less, more preferably 25 nm or less, even more preferably 20 nm or less. The difference between the maximum value and the minimum value of the in-plane retardation is preferably 5 nm or less, more preferably 3 nm.
It is as follows.

Since the light guide plate of the present invention is excellent in heat resistance and low optical distortion, it can be widely used as a lighting device for a liquid crystal display, particularly a front light type lighting device.

[0052]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited by these examples. In the following, “parts” indicates “parts by weight”.

Reference Example 1 Synthesis Method of Norbornene-Based Thermoplastic Resin: (A-1) 8-Methyl-8-methoxycarbonyltetracyclo [4.4.0.12, 5.17,10] -3- 250 parts of dodecene (specific monomer), 41 parts of 1-hexene (molecular weight modifier), and 750 of toluene (solvent for ring-opening polymerization reaction)
The reaction solution was charged in a reaction vessel in which
Heated to 0 ° C. Then, a toluene solution of triethylaluminum (1.5 mol / l) was added to the solution in the reaction vessel.
0.62 parts of a toluene solution of tungsten hexachloride (t-butanol: methanol: tungsten = 0.35 mol: 0.3 mol: 1 mol) modified with t-butanol / methanol (concentration: 0.05 mol / l) ), And the mixture was heated and stirred at 80 ° C for 3 hours to cause a ring-opening polymerization reaction to obtain a ring-opening polymer solution. The polymerization conversion in this polymerization reaction was 97%.

The ring-opened polymer solution 4 thus obtained
000 parts was charged into an autoclave, and RuHCl (CO) [P (C6H5) 3] 30.
48 parts were added, and the mixture was heated and stirred for 3 hours under the conditions of a hydrogen gas pressure of 100 kg / cm 2 and a reaction temperature of 165 ° C., thereby causing a hydrogenation reaction. After cooling the obtained reaction solution (hydrogenated polymer solution), the pressure of hydrogen gas was released. The hydrogenated polymer thus obtained: 60 MH of (A-1)
z, the hydrogenation rate measured by 1H-NMR is substantially 100%
Met.

Reference Example 2 Method for Synthesizing Norbornene-Based Thermoplastic Resins: (A-2) to (A-4) Ring opening using the specific monomers shown in Table 1 in the same manner as in Reference Example 1. Hydrogenated (co) polymer: (A-2) to (A-
4) was obtained. The hydrogenation rate of the obtained olefinically unsaturated bonds (A-2) to (A-4) measured at 60 MHz and 1H-NMR was substantially 100%. However, (A-
The aromatic ring of 4) was not substantially hydrogenated. In addition,
The molecular weights (ηinh) of (A-2) to (A-4) were adjusted by appropriately selecting the amount of 1-hexene added as a molecular weight regulator. (A-1) to (A-) obtained in Reference Examples 1 and 2.
4) Molecular weight (ηinh) and glass transition temperature (Tg)
Are shown in Table 1.

Other thermoplastic resins used in Comparative Examples: methacrylic resin: specific gravity = 1.19, Tg = 108 ° C., M
FR (260 ° C., 10 kg load) = 154 Polycarbonate resin: specific gravity = 1.20, Tg = 146
° C, MFR (260 ° C, 10 kg load) = 34

[0057]

[Table 1]

[Examples 1 to 6 and Comparative Examples 1 to 5] (Production method of light guide plate) A resin sheet was formed according to the following method, the shape of the prism pattern was transferred, and then an antireflection film was formed. Thus, a light guide plate was manufactured. Tables 2 and 3 show the resin, the method of forming the resin sheet, and the method of forming the antireflection film used in each of the examples and comparative examples. 1) Manufacturing method of sheet or flat plate Manufacturing method: A thermoplastic resin is melted at 300 ° C. in a 90 mm vented extruder (GM90-32V, manufactured by M.M.E.C.) and using a gear pump (MSDP240, manufactured by Normac). 65
Discharge rate 120kg / h from 0mm width coat hanger die
Extruded into a film at r. The sheet was guided to a single-sided belt-type roll having a cast drum heated to 160 ° C. by an oil temperature control unit, and polished with a roll having a peripheral speed of 4 m / min. At this time, the sheet temperature when the sheet was released from the pressure between the belt and the cast drum was 161 ° C. Further, while controlling the sheet tension to 5 kgf by the tension control unit, a 0.8 mm thick sheet was taken out. Production method: Dissolve in methylene chloride so that the concentration of the thermoplastic resin becomes 30% by weight. Further, the solution was cast on a stainless steel endless belt having a width of 500 mm. Thereafter, the first-stage drying is performed on the endless belt at 40 ° C. for 40 minutes, the film is peeled from the endless belt, and then the second-stage drying is performed at 100 ° C. for 180 minutes. Further, the drying room was moved to an atmosphere of 120 ° C., and finally the third-stage drying was performed for 120 minutes to obtain a resin film having a thickness of 0.5 mm. The residual solvent concentration of the obtained film was 0.12%. Production method: After drying the thermoplastic resin in a vacuum dryer maintained at 100 ° C. for 4 hours, 100 × 1 by injection molding.
A molded product having a thickness of 50 mm and a thickness of 0.8 mm was obtained. The mold used was a mirror-finished one, and the molding machine was SG75M-2 manufactured by Sumitomo Heavy Industries, Ltd.
It was used. The molding conditions were a resin temperature of 320 ° C. and a mold temperature of 140 ° C.

2) Method for Transferring Prism Pattern Shape The sheet obtained by the above method was cut into a size of 50 mm × 70 mm using a laser cutting machine. Furthermore, the pitch 250μm,
By pressing a mold in which a continuous prism having a height of 10 μm is cut, a concave and convex having a prism function having a cross-sectional shape shown in FIG. 1 (left and right sides and a bottom side are omitted in a broken form). Formed a continuous pattern. The mold surface temperature in this case was set to the glass transition temperature Tg of the used norbornene-based plastic resin material +15 to 25 ° C.

3) Method of forming antireflection film The sample on which the prism pattern was transferred by the above method was used as a test piece, and an antireflection film coating layer was formed on the mirror side where no prism was formed. Coat: under vacuum of 10-4 Torr, SiO: 140n
m, then TiO2: 120 nm, SiO2: 1 on the outermost layer
70 nm was deposited. In this case, the substrate surface temperature is 100 ° C.
Met. Coat: 70 parts of a copolymer having a number average molecular weight (polystyrene conversion value by GPC measurement) of 4.5 × 104 obtained by copolymerizing 70 parts of vinylidene fluoride and 30 parts of hexafluoropropylene, and 30 parts of dipentaerythritol hexaacrylate as a solvent Was added to 2500 parts of methyl isobutyl ketone, and stirred and mixed for 1 hour to obtain a coating material having a concentration of 4%. This paint is applied on the same test piece as that of the coat 1 by dipping, and then heated to 60 ° C. to sufficiently evaporate the solvent, and an electron beam is applied thereto using an electron beam irradiator so that the dose becomes 3 Mrad. Cured by irradiation

With respect to the light guide plate of each example obtained as described above, a test for measuring characteristics under the following conditions was performed. * Durability The light guide plate was held in a gear oven and a constant temperature and humidity chamber, and the shapes of the molded plates before and after the test were compared.・ Heat resistance 100 ℃ × 300 hours ・ Humidity and heat resistance 85 ℃, 85RH% × 300 hours Evaluation was performed in the following three stages ○ -No change △ -Small change x-Large change ※ Optical strain Birefringence measurement device (Oji measurement The maximum value and the minimum value of the in-plane residual retardation were measured by KOBRA-21ADH manufactured by K.K. * Adhesion of anti-reflection film Initial adhesion: adhesion immediately after film formation. Durable adhesion: adhesion after 100 ° C. × 300 hours. The evaluation was performed on a 1 mm × 1 mm square 100 on the antireflection film side.
Each piece was cut with a cutter, a cellophane tape peeling test was performed, and the test was performed according to the following evaluation criteria. ：: The number of peeled eyes is 0 Δ: The number of peeled eyes is 1 to 10 ×: The number of peeled eyes exceeds 10

The results of the above test are shown in Tables 2 and 3. From these results, it is understood that the light guide plate of the present invention has excellent heat / moisture / heat resistance, low birefringence, and extremely small optical distortion.

[0063]

[Table 2]

[0064]

[Table 3]

[0065]

The light guide plate of the present invention has excellent heat / moisture / heat resistance, low birefringence and extremely low optical distortion. Therefore,
Most suitable as a light guide plate used for front lights and the like.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional shape of a sheet-like molded product having a prism pattern (irregularities) on a surface obtained in an example.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Kasai, 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72) Zengen Wada, 2--11-24 Tsukiji, Chuo-ku, Tokyo Jay F-term in SR Co., Ltd. (reference) 2H038 AA55 BA06 2H091 FA14X FA16X FA23X FB02 FC01 FC19 LA12 4F209 AA12 AC03 AH73 PA03 PB02 PC05 PG12 PQ01

Claims (5)

[Claims] 1. A sheet obtained by molding a molding material containing a norbornene-based thermoplastic resin by melt extrusion molding or a solution casting method, and reflects and / or reflects light on at least one surface of a sheet.
Alternatively, a light guide plate formed with irregularities having a function of refraction. 2. The light guide plate according to claim 1, wherein the norbornene-based thermoplastic resin has a polar group. 3. The light guide plate according to claim 1, wherein the light guide plate is a light guide plate for a front light. 4. A molding material containing a norbornene-based thermoplastic resin is formed into a sheet by melt extrusion or solution casting, and at least one surface of the obtained sheet has a function of reflecting and / or refracting light. The method for manufacturing a light guide plate according to claim 1, wherein the unevenness is transferred from a mold. 5. The shape formed on the roll surface by rotating the roll mold while pressing the surface of the sheet against the surface of the roll mold, wherein the mold has a roll shape on the surface. The method according to claim 4, wherein is transferred onto the surface of the sheet.