JP4679808B2 - Composition for forming retardation film - Google Patents

Description

  The present invention relates to a retardation film-forming composition containing particles having optical anisotropy, a retardation film formed using the retardation film-forming composition, a retardation element having the retardation film, and The present invention relates to a polarizing plate and a liquid crystal display element using these.

  In recent years, liquid crystal display devices (LCD) have been widely used in notebook personal computers, personal computer monitors, car navigation systems, TV monitors, and the like. It has been pointed out from the beginning that this liquid crystal display device is inferior in viewing angle characteristics as compared to a cathode ray tube (CRT), and various studies have been made for improving the viewing angle characteristics.

  For example, one method for improving viewing angle characteristics is to use a stretched film obtained by subjecting a transparent film such as polycarbonate to uniaxial or biaxial stretching as a retardation film. However, in this method, in order to improve the viewing angle characteristics over a wide range, it is necessary to bond a plurality of stretched films. For each stretched film, the birefringence is controlled, or the stretched film bonding angle is precise. It has been necessary to control the production cost, which has contributed to high manufacturing costs.

  In addition, in order to improve the viewing angle characteristics of TN type LCDs, which occupy the mainstream of liquid crystal display devices, the angle dependency of all liquid crystal molecules hybrid-aligned in the liquid crystal cell when the voltage is on (black display) is compensated. A retardation film has become necessary. For this reason, a retardation film in which a liquid crystalline discotic compound that can be a negative compensation film is hybrid-aligned and a retardation film in which a rod-shaped liquid crystalline compound is hybrid-aligned have been proposed. It is known that the viewing angle characteristics in the three directions, left and right and up and down, can be improved by using it.

  However, the film using these liquid crystalline compounds may change the viewing angle characteristics over a long period of use from the standpoint of stability of the liquid crystalline compound itself or the hybrid alignment formed by the liquid crystalline compound.

  In addition, the VA method, which has recently become the mainstream in TV monitors, displays a black state by vertically aligning a liquid crystal layer while the voltage is OFF, and a change in phase difference due to a viewing angle is large.

  Under these circumstances, there has been a growing need for an optical compensation film for a liquid crystal display device that can be applied to various liquid crystal types and that can maintain good viewing angle characteristics and the like over a long period of use.

  In addition, a laser beam pick-up device required for reading and writing of an optical disk such as a DVD or a CD-R is a wave plate obtained by coating a liquid crystal on a retardation film obtained by stretching a transparent film or a glass substrate. It is used as However, stretched retardation films may cause aberration problems due to phase variations and film surface waviness, and those coated with liquid crystals may change their properties over a long period of use. .

On the other hand, an antireflection film formed from a composition containing acicular particles is known (Patent Document 1).
And Patent Document 2). This antireflection film has improved antistatic properties, scratch resistance and transparency, and no disclosure is made on the birefringence of the film.

Further, Patent Document 3 discloses an optical resin material containing a transparent polymer resin and an inorganic substance having birefringence, and an acicular crystalline mineral is exemplified as the inorganic substance. However, this optical resin material is obtained by orienting an inorganic substance having a refractive index opposite to the birefringence generated by the orientation of the polymer resin so as to cancel the orientation refractive index of the polymer resin. 3, the difference between the refractive index in the major axis direction and the refractive index in the direction perpendicular to the major axis direction of the inorganic substance having birefringence causes a difference in refractive index between the film plane direction and the film thickness direction. This is not disclosed.
JP 2002-293839 A JP 2002-355936 A JP-A-11-293116

  The present invention is intended to solve the problems associated with the prior art as described above, and uses a retardation film, a retardation element, a polarizing plate, and the like that stably express good optical characteristics over a long period of time. It is an object of the present invention to provide a liquid crystal display element and a composition for forming the retardation film.

  The present inventor has intensively studied to solve the above problems, and forms a retardation film having excellent birefringence by arranging inorganic particles having both shape anisotropy and birefringence in the film. We found out what we could do and came to complete the invention.

That is, the composition for forming a retardation film according to the present invention is
(A) inorganic particles exhibiting shape anisotropy having a major axis and a minor axis, and having a refractive index in the major axis direction larger than an average refractive index in a direction perpendicular to the major axis direction, and birefringence;
(B) A retardation film-forming composition containing a binder that is a curable compound for fixing the inorganic particles (A),
The retardation film formed from the composition causes a difference in refractive index between the film surface parallel direction and the film thickness direction, and the film surface parallel direction refractive index is larger than the film thickness direction refractive index. It is said.

In the retardation film formed from the composition, the composition for forming the retardation film is arranged such that the major axis direction of the inorganic particles (A) is substantially parallel to the film plane,
Due to the difference between the refractive index in the major axis direction of the inorganic particles (A) and the refractive index in the direction perpendicular to the major axis direction, a difference in refractive index between the film surface parallel direction and the film thickness direction is caused in the retardation film. Is preferred. The difference between the refractive index in the film surface parallel direction and the refractive index in the film thickness direction of the retardation film is preferably 0.010 or more.

Before SL inorganic particles (A) preferably has an average major axis is an inorganic particle having the crystalline 2 [mu] m.
The curable compound comprises (i) a melamine compound, (ii) an isocyanate compound, (iii)
It is preferably an acrylate compound, (iv) an epoxy compound, or (v) a hydrolyzable silane compound. The amount of the binder (B) added is preferably 1 to 200 parts by weight with respect to 100 parts by weight of the inorganic particles (A).
The composition for forming a retardation film can also contain a curing initiator (C).

  The composition for forming a retardation film according to the present invention is excellent in coating performance and can form a retardation film excellent in birefringence and transparency. In addition, the retardation film according to the present invention stably exhibits excellent birefringence and transparency over a long period of time, and also exhibits good viewing angle characteristics.

  Hereinafter, the composition for forming a retardation film, the retardation film, the retardation element, the polarizing plate, and the liquid crystal display element according to the present invention will be described in more detail.

<Phase difference film forming composition>
The composition for forming a retardation film according to the present invention is a composition containing specific inorganic particles and a binder, and can form a retardation film having birefringence as described later.

(A) Inorganic particles:
The inorganic particles used in the present invention exhibit shape anisotropy having a major axis and a minor axis, and have a refractive index in the major axis direction larger than an average refractive index in a direction perpendicular to the major axis direction, and have birefringence. (Hereinafter referred to as “inorganic particles (A)”). Here, the long diameter means the longest diameter (hereinafter also referred to as “a-axis”) of the inorganic particles (A), and the short diameter means the shortest diameter among the axes perpendicular to the a-axis (hereinafter referred to as “b-axis”). ")". In this specification, an axis perpendicular to both the a-axis and the b-axis is defined as “c-axis”.

Inorganic particles (A), the length of a-axis (major axis: L _a) and the length of b-axis (short diameter: D _b) the ratio of ( "aspect ratio") is (L _a / D _b), Usually, it is 1.5 or more, preferably 2.0 or more, more preferably 5.0 to 10000, particularly preferably 10.0 to 1000. The length of the c axis (D _c) and the length of the b-axis (D _b) the ratio of (D _c / D _b) is generally 1.0 to 1.5, preferably 1.0 to 1. 3. When the aspect ratio (L _a / D _b ) is within the above range, when forming the retardation film, the inorganic particles (A) can be easily formed so that the major axis direction of the inorganic particles (A) is parallel to the film plane. The birefringence of the retardation film can be easily controlled. When the aspect ratio (L _a / D _b ) is less than 1.5, the inorganic particles (A) may be arranged in any direction in the film, and the resulting film has birefringence. May not have. For this reason, in particular, acicular inorganic particles are preferably used.

  The average major axis of the inorganic particles (A) is not particularly limited as long as a transparent retardation film can be formed, but is usually 2 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less, particularly preferably 0.1 μm or less. is there. Here, the average major axis is the number average value (n = 100) of the major axis of the particles measured by observation with a transmission electron microscope. When the average major axis exceeds the above upper limit, the inorganic particles may not be uniformly dispersed, and storage stability may be lacking, and when forming a retardation film, the inorganic particles are likely to settle, and are obtained by light scattering. The transparency of the film may decrease, and the turbidity (haze value) may increase.

  The inorganic particles (A) may contain particles having a major axis of 10 μm or more as long as the average major axis is in the above range, but the particles having a major axis of 10 μm or more are preferably less than 10% by weight, more preferably. Is less than 5% by weight, particularly preferably less than 1% by weight, most preferably less than 0.1% by weight. When the content of particles having a major axis of 10 μm or more is in the above range, the light transmittance can be increased, and the difference between the refractive index in the film surface parallel direction and the refractive index in the film thickness direction of the obtained retardation film. Will also be easier to control.

The inorganic particles (A) are particles having birefringence in which the refractive index in the a-axis direction (major axis direction) is larger than the average refractive index in the direction orthogonal to the major axis direction. Refractive index in the a-axis direction (major axis direction) (n _a
) And the difference between the average value of the refractive index in the direction orthogonal to the a-axis _{(n r) (Δn p =} n a -n r) is parallel to the film surface direction of the refractive index of the obtained retardation film and the film thickness Although it will not specifically limit if the difference with the refractive index of a direction becomes the range which is mentioned later, Usually, 0.010 or more, Preferably it is 0.050 or more, More preferably, it is 0.100 or more, Especially preferably, it is 0.00. 200 or more. When this Δn _p is in the above range, the refractive index in the film thickness direction of the retardation film can be easily adjusted, and the difference between the refractive index in the film surface parallel direction and the refractive index in the film thickness direction can be easily controlled. can do.

  In addition, the inorganic particles (A) have an average value of the refractive index in the a-axis direction (major axis direction) and the refractive index in the direction orthogonal to the a-axis, that is, the average refractive index of the entire particle is usually less than 3, preferably 2. 5 or less, more preferably 2.0 or less. When the average refractive index of the entire particle is in the above range, light scattering in the formed retardation film can be suppressed.

As the inorganic particles (A) having both shape anisotropy and birefringence, an inorganic compound in which the refractive index in the major axis direction is larger than the refractive index in the direction perpendicular to the major axis direction when the particles are formed. As long as it is a particle having a main component, specifically, the component has a remarkable birefringence, and the relationship between the particle shape and the refractive index satisfies the above-described conditions, SiC, ZnS, _{As 2 Se 3, LiNbO 3,} TiO 2, SnO 2, BaTiO 3, BeO, is MgF _2, KH ₂ PO ₄ are preferred, TiO _2, especially rutile, SnO _2, Al ₂ O ₃ corundum doped with antimony Is preferred .

As the particles containing the inorganic compound as a main component, if the inorganic particles have both shape anisotropy and birefringence as described above, for example, the following finely pulverized inorganic minerals should be used. Can do.
Sulphide minerals such as pyrite steel, chalcopyrite, cinnabar, porphyry steel, chicken calcite, and stone yellow;
Oxidizing minerals such as spinel, corundum, red iron steel, gold red stone, gold green stone, and protein stone;
Quartz, such as quartz, red quartz, jasper and chalcedony;
Halogenated minerals such as fluorite, cryolite and rock salt;
Carbonate minerals such as calcite, aragonite, chrysantumite, peacock stone, kyanite, etc .;
Sulphate minerals such as barite, celestite, gypsum and lead ore;
Phosphate minerals such as turquoise, barisherite, apatite and strength stone;
Arsenate minerals such as Adamite;
Meteorite, stone meteorite, topaz, zircon, kyanite, columbite, datoite, chlorite, habitite, vesuvite, beryl, tourmaline, chalcopyrite, cordierite, axite, beni, to Stone, diopside, lithiateite, jadeite, hornblende, leebeckite, rose pyroxene, wollastonite, talc, pylorite, muscovite, biotite, lithia mica, grapestone, fisheye stone, serpentine, blue Silicate minerals such as gold stone and sodalite;
Feldspars such as potash feldspar, plagioclase, feldspar;
Zeolites such as calcite, chabazite, pyroxenite, lumbarite, soda zeolite, turbidite, etc .;
Examples include tungstate minerals; molybdenum minerals; borate minerals; vanadate minerals.

  In addition, such inorganic minerals are used as the main raw material, and other components are mixed as required, and from the melt by methods such as the CZ method, FZ method, skull melt method, Bernoulli method, Bridgman method, etc. A melt method for growing a single crystal; a solution method for growing a single crystal mainly by dissolving water in a solvent; an inorganic substance melted instead of water, such as lead oxide, lead fluoride, molybdenum oxide, tungsten oxide, boron oxide Crystal growth by a flux method using vanadium oxide or the like as a solvent; Hydrothermal method mainly used in quartz; Gas phase method such as CVD or PVD; Sol-gel method or the like as described above Inorganic particles (A) having both anisotropy and birefringence can also be prepared.

The structure of the inorganic particles (A) is not particularly limited as long as it has both shape anisotropy and birefringence as described above. Is preferable, and a single crystal is particularly preferable. By using the crystalline inorganic particles (A), the birefringence of the retardation film can be expressed more accurately and efficiently. Further, the crystal system is not particularly limited as long as the particles have both shape anisotropy and birefringence as described above, and any of triclinic, monoclinic, oblique, ridge, square, hexagonal, and cubic can be used. Good.

  The inorganic particles (A) are usually 1 to 95% by weight, preferably 5 to 70% by weight, more preferably 5 to 50% by weight, particularly preferably 5 to 30% by weight, based on the total amount of the retardation film forming composition. Contained. When the content of the inorganic particles (A) is in the above range, the composition for forming a retardation film exhibits good coating properties, and the birefringence of the obtained retardation film is particularly excellent.

  In order to further improve the dispersibility of the inorganic particles (A) or to further improve the adhesion with the component formed by the binder (B) described later when a retardation film is formed, a coupling agent or the like You may surface-treat with the processing agent. By using the surface-treated inorganic particles (A), not only the dispersibility is further improved, but also the transparency of the obtained retardation film is ensured over a long period of time, and the storage stability of the retardation film forming composition is further improved. It can be improved further. Here, the surface treatment means an operation of modifying the surface by mixing the inorganic particles (A) and the surface treatment agent, and the method comprises applying a surface treatment agent to the inorganic particles (A). Any of the method of physical adsorption and the method of chemically bonding the inorganic particles (A) and the surface treatment agent may be used, but from the viewpoint of the effect of the surface treatment, the method of chemically bonding is preferably used.

As the surface treatment agent, isopropyl triisostearoyl titanate, titanium n-butoxide, titanium ethoxide, titanium 2-ethylhexoxide, titanium isobutoxide, titanium isopropoxide, titanium methoxide, titanium methoxypropoxide, Titanium n-nonyl oxide, titanium n-propoxide, titanium stearyl oxide, triisopropoxy heptadecinate titanium;
Compound groups having an unsaturated double bond in the molecule such as γ-methacryloxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane; γ-glycidoxypropyltriethoxysilane, γ-glycyl Compounds having an epoxy group in the molecule such as sidoxypropyltrimethoxysilane;
compounds having an amino group in the molecule such as γ-aminopropyltriethoxysilane and γ-aminopropyltrimethoxysilane;
compounds having a mercapto group in the molecule such as γ-mercaptopropyltriethoxysilane and γ-mercaptopropyltrimethoxysilane;
Alkylsilanes such as methyltrimethoxysilane, methyltriethoxysilane, and phenyltrimethoxysilane;
Examples of the coupling agent include tetrabutoxy titanium, tetrabutoxy zirconium, and tetraisopropoxy aluminum. These coupling agents can be used alone or in combination of two or more.

Examples of commercially available coupling agents include A-1100, A-1102, A-1110, A-1120, A-1122, Y-9669, A-1160, AZ-6166 manufactured by Nippon Unicar Co., Ltd. , A-151, A-171, A-172, A-174, Y-9936, AZ-6167, AZ-6134, A-186, A-187, A-189, AZ-6129, A-1310, AZ -6189, A-162, A-163, AZ-6171, A-137, A-153, A-1230, A-1170, A-1289, Y-5187, A-2171, Y-11597, etc. Examples include SH6020, SH6023, SH6026, SZ6030, SZ6032, AY-43-038, SH6040, SZ6050, SH6062, SH6076, SZ6083, and SZ6300 manufactured by Corning Silicone.

The surface treatment agent is usually added in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the inorganic particles (A). It is desirable. When the addition amount of the surface treatment agent is less than the above lower limit, the surface treatment effect may not be sufficiently exhibited, and when the addition amount of the surface treatment agent exceeds the above upper limit, it is unreacted in the composition for forming a retardation film. A large amount of the surface treatment agent remains, and the storage stability of the composition may deteriorate, and the antistatic performance and mechanical strength of the retardation film may be insufficient.

  A retardation film formed using the retardation film-forming composition by containing the inorganic particles (A) having both shape anisotropy and birefringence in the retardation film-forming composition. The birefringence of can be easily controlled.

(B) Binder:
The binder (B) used in the present invention is preferably one that can immobilize the inorganic particles (A) and has little visible light absorption. Specific examples include melamine compounds, isocyanate compounds, acrylate compounds, epoxidized products, hydrolyzable silane compounds, and homopolymers or copolymers thereof, homocondensates or cocondensates, and hydroxyl group-containing polymers. . Furthermore, high molecular compounds such as polycarbonate, triacetyl cellulose (TAC), polystyrene, cyclic olefin resins such as norbornene resin described later, and polyethersulfone can also be used. These can be used individually by 1 type or in mixture of 2 or more types.

  Moreover, it is preferable to use these, melt | dissolving in the organic solvent (D) mentioned later. The concentration of these compounds with respect to the organic solvent (D) is preferably 5 to 95% by weight, more preferably 10 to 90% by weight, and particularly preferably 20 to 80% by weight. If the concentration of the polymer compound is less than the above lower limit, the thickness of the retardation film may become too thin, or adjustment of the film thickness may be difficult if the film thickness is increased. On the other hand, when the concentration of the polymer compound exceeds the above upper limit, it may be difficult to make the thickness of the retardation film uniform.

  In the present invention, by using the binder (B) as described above, not only the inorganic particles (A) can be fixed, but also the scratch resistance, transparency, birefringence and stability of these properties of the retardation film. It can also improve sex.

  Moreover, in this invention, a sclerosing | hardenable compound is used preferably among the above binders (B). By using the curable compound, the dispersibility of the inorganic particles (A) and the adhesion to the binder are further improved, and the arrangement of the inorganic particles (A) in the retardation film exhibits birefringence. In addition, scratch resistance, transparency, solvent resistance, and durability stability of these characteristics of the obtained retardation film are further improved.

  Specific examples of the curable compound include the following compounds.

(I) Melamine compounds:
The melamine compound used in the present invention is most preferably a melamine compound having two or more of any one of a methylol group and an alkoxylated methyl group or the aforementioned substituent in the molecule. Specific examples include methylated melamine compounds such as hexamethyl etherified methylol melamine compounds, hexabutyl etherified methylol melamine compounds, methylbutyl mixed etherified methylol melamine compounds, methyl etherified methylol melamine compounds, and butyl etherified methylol melamine compounds.

  Moreover, in this invention, you may use together the hydroxyl-containing polymer which can react with this melamine compound. Examples of such a hydroxyl group-containing polymer include polyvinyl acetal resin (polyvinyl butyral resin, polyvinyl formal resin), polyvinyl alcohol resin, polyacrylic resin, polyphenolic resin, phenoxy resin, and the like. These resins can be used alone or in combination of two or more.

Of these resins, polyvinyl butyral resins (including modified polyvinyl butyral resins) that are excellent in adhesion to the substrate and mechanical properties and in which uniform dispersion of the inorganic particles (A) is relatively easy are most preferable.

(Ii) Isocyanate compound:
In the present invention, the isocyanate compound is not particularly limited as long as it has an isocyanate group capable of reacting with a hydroxyl group-containing polymer. The said hydroxyl-containing polymer can use the same polymer as the hydroxyl-containing polymer used together with a melamine compound. Specific examples of the isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate. 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate , 3,3′-dimethylphenylene diisocyanate, 4,4′-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethylhexamethylene diisocyanate, bis (2-isocyanatoethyl) Malate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,3-bis (isocyanate) Methyl) cyclohexane, tetramethylxylylene diisocyanate, 2,5 (or 2,6) -bis (isocyanatomethyl) -bicyclo [2.2.1] heptane, and the like. These isocyanate compounds can be used individually by 1 type or in mixture of 2 or more types.

  Of these isocyanate compounds, 2,4-tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, methylene bis (4-cyclohexyl isocyanate), and 1,3-bis (isocyanate methyl) cyclohexane are preferred.

(Iii) Acrylate compound:
The acrylate compound used in the present invention is not particularly limited as long as it has at least one (meth) acryloyl group in the molecule. For example, a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound are mentioned. Among these, a polyfunctional (meth) acrylate compound is preferable, and the reactivity of the retardation film forming composition can be improved.

Specific examples of the monofunctional (meth) acrylate compound include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, tert -Butyl (meth) acrylate, pentyl (meth) acrylate, amyl (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 , Alkyl (meth) acrylates such as lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate;
Hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and the like Of phenoxyalkyl (meth) acrylates;
Alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate;
Polyethylene glycol (meth) acrylates such as polyethylene glycol mono (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate;
Polypropylene glycol (meth) acrylates such as polypropylene glycol mono (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, nonylphenoxy polypropylene glycol (meth) acrylate;
Cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, bornyl (meth) acrylate, isobornyl ( Cycloalkyl (meth) acrylates such as (meth) acrylate and tricyclodecanyl (meth) acrylate;
Examples include benzyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate and the like. These monofunctional (meth) acrylate compounds can be used individually by 1 type or in mixture of 2 or more types.

Specific examples of the polyfunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4 -Alkylene glycol di (meth) acrylates such as butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate;
Trimethylolpropane tri (meth) acrylate, trimethylolpropane trihydroxyethyl tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa Poly (meth) acrylates of polyhydric alcohols such as (meth) acrylate and hydroxypivalate neopentyl glycol di (meth) acrylate;
Isocyanurate poly (meth) acrylates such as isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate;
Poly (meth) acrylates of cycloalkanes such as tricyclodecanediyldimethyldi (meth) acrylate;
Di (meth) acrylate of bisphenol A ethylene oxide adduct, di (meth) acrylate of propylene oxide adduct of bisphenol A, di (meth) acrylate of alkylene oxide adduct of bisphenol A, ethylene oxide addition of hydrogenated bisphenol A Di (meth) acrylate, di (meth) acrylate of propylene oxide adduct of hydrogenated bisphenol A, di (meth) acrylate of alkylene oxide adduct of hydrogenated bisphenol A, bisphenol A diglycidyl ether and (meth) acrylic (Meth) acrylate derivatives of bisphenol A such as (meth) acrylate obtained from acids;
3,3,4,4,5,5,6,6-octafluorooctanedi (meth) acrylate, 3- (2-perfluorohexyl) ethoxy-1,2-di (meth) acryloylpropane, Nn And fluorine-containing (meth) acrylates such as -propyl-N-2,3-di (meth) acryloylpropyl perfluorooctylsulfonamide. These polyfunctional (meth) acrylate compounds can be used individually by 1 type or in mixture of 2 or more types.

  Among these polyfunctional (meth) acrylate compounds, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, etc. have many acryloyl groups contained in one molecule, and the crosslinking density A polyfunctional (meth) acrylate compound that can improve the thickness and give excellent film hardness is particularly preferred.

(Iv) Epoxy compound:
The epoxy compound used in the present invention is not particularly limited as long as it has at least one epoxy group in the molecule. Examples thereof include bisphenol type epoxy compounds, novolac type epoxy compounds, alicyclic epoxy compounds, aliphatic epoxy compounds, aromatic epoxy compounds, glycidylamine type epoxy compounds, halogenated epoxy compounds and the like.

Specifically, bisphenol type epoxy compounds such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether;
Novolac epoxy compounds such as phenol novolac epoxy compounds and cresol novolac epoxy compounds;
3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3 , 4-epoxycyclohexylmethyl) adipate, vinylcyclohexylene oxide, 4-vinylepoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3 ′, 4 '-Epoxy-6'-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylene bis (3,4 Epoxycyclohexanecarboxylate), epoxidized tetrabenzyl alcohol, lactone-modified 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, lactone-modified epoxidized tetrahydrobenzyl alcohol, cyclohexene oxide, hydrogenated bisphenol A diglycidyl Alicyclic epoxy compounds such as ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol AD diglycidyl ether;
Aliphatic epoxy compounds such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether;
Halogenated epoxy compounds such as brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether;
Examples thereof include glycidylamine type epoxy compounds such as tetraglycidylaminophenylmethane.

In addition to the above compounds, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers; obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin. Polyglycidyl ethers of polyether polyols; diglycidyl esters of aliphatic long-chain dibasic acids; monoglycidyl ethers of higher aliphatic alcohols; polyethers obtained by adding phenol, cresol, butylphenol or alkylene oxides to these Monoglycidyl ethers of alcohol; glycidyl esters of higher fatty acids; epoxidized soybean oil, butyl epoxy stearate, octyl epoxy stearate, epoxy Such as linseed oil, and the like.

  Moreover, the epoxy resin which superposed | polymerized 1 type or 2 types or more of these compounds in the suitable range suitably can also be used.

  Furthermore, as an epoxy compound used in the present invention, a polymer of a conjugated diene monomer, a copolymer of a conjugated diene monomer and a compound having an ethylenically unsaturated bond group, a diene monomer and an ethylenically unsaturated bond group And a compound obtained by epoxidizing a (co) polymer such as a natural rubber and a copolymer.

  Among these epoxy compounds, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane- An alicyclic epoxy compound having excellent curability such as meta-dioxane is particularly preferable.

(V) Hydrolyzable silane compound:
The hydrolyzable silane compound used in the present invention is not particularly limited as long as it has at least one hydrolyzable group in the molecule. Examples thereof include hydrolyzable silane compounds exemplified in JP-A 2000-1648 and the like, and single condensates or cocondensates of the hydrolyzable silane compounds. Moreover, a commercial item can be used for the condensate of a hydrolysable silane compound. For example, it can be obtained as KR282, KR155, KR211, Polon MF40, KC89, KC88 (manufactured by Shin-Etsu Silicone).

  The amount of the binder (B) added is not particularly limited as long as it can fix the inorganic particles (A) when the retardation film is formed, but is usually 0 with respect to 100 parts by weight of the inorganic particles (A). 0.01 to 1,000 parts by weight, preferably 0.1 to 300 parts by weight, more preferably 1 to 200 parts by weight is desirable. When the addition amount of the binder (B) is less than the above lower limit, the curability may be lowered when the retardation film is formed using the retardation film forming composition, and the addition amount of the binder (B) is When the upper limit is exceeded, the storage stability of the composition for forming a retardation film may be lowered. In addition, by forming a retardation film using a retardation film-forming composition containing the binder (B) in an amount in the above range, the scratch resistance, solvent resistance, transparency, and birefringence of the retardation film are formed. The characteristics such as sex are further improved.

(C) Curing initiator:
The composition for forming a retardation film according to the present invention preferably further contains a curing initiator (C). By adding the curing initiator (C), the retardation film can be formed in a short time and with low energy.

  Examples of the curing initiator (C) used in the present invention include a thermal acid generator, a photoacid generator, a photopolymerization initiator (photo radical generator), and the like. These curing initiators can be used alone or in combination of two or more.

(I) Thermal acid generator:
In the present invention, it is preferable to use a thermal acid generator in curing the melamine compound, curing the melamine compound and the hydroxyl group-containing polymer, and curing the epoxy compound. Specific examples of the thermal acid generator include aliphatic sulfonic acid, aliphatic sulfonate, aliphatic carboxylic acid, aliphatic carboxylate, aromatic sulfonic acid, aromatic sulfonate, aromatic carboxylic acid, aromatic Examples thereof include carboxylates, metal salts, and phosphate esters. These thermal acid generators can be used alone or in combination of two or more.

  Among such thermal acid generators, aromatic sulfonic acid is most preferable as the thermal acid generator used for curing the melamine compound and curing the melamine compound and the hydroxyl group-containing polymer. In this case, the curing rate can be further improved by using aromatic sulfonic acid.

  The amount of the thermal acid generator added is not particularly limited as long as the curing reaction proceeds sufficiently, but is usually 0.1 to 15 parts by weight, preferably 1 to 10 parts per 100 parts by weight of the binder (B). A part by weight is desirable. When the addition amount of the thermal acid generator is less than the above lower limit, the curing reaction of the binder (B) does not proceed sufficiently, and a retardation film having sufficient hardness may not be obtained. Moreover, when the addition amount of a thermal acid generator exceeds the said upper limit, the weather resistance and heat resistance of the phase difference film obtained may fall.

(Ii) Photoacid generator:
In the present invention, as in the case of the thermal acid generator, the curing of the melamine compound, the curing of the melamine compound and the hydroxyl group-containing polymer, and the curing of the condensate of epoxy compound, hydrolyzable silane compound, and hydrolyzable silane compound In this case, it is also preferable to use a photoacid generator. Specific examples of the photoacid generator include (4-n-decyloxyphenyl) phenyliodonium hexafluoroantimonate, [4- (2-hydroxy-n-tetradecyloxy) phenyl] phenyliodonium hexafluoroantimonate, [ 4- (2-hydroxy-n-tetradecyloxy) phenyl] phenyliodonium trifluorosulfonate, [4- (2-hydroxy-n-tetradecyloxy) phenyl] phenyliodonium hexafluorophosphate, [4- (2-hydroxy -N-tetradecyloxy) phenyl] phenyliodonium tetrakis (pentafluorophenyl) borate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate, bis (4-t-butylphenyl) iodonium hexaful Lophosphate, bis (4-t-butylphenyl) iodonium trifluorosulfonate, bis (4-t-butylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoro Borate, bis (dodecylphenyl) iodonium hexafluorophosphate, bis (dodecylphenyl) iodonium trifluoromethylsulfonate, diphenyldisulfone, ditosyldisulfone, bis (phenylsulfonyl) diazomethane, bis (chlorophenylsulfonyl) diazomethane, bis (xylylsulfonyl) ) Diazomethane, phenylsulfonylbenzoyldiazomethane, bis (cyclohexylsulfonyl) methane, 1,8 Naphthalenedicarboxylic acid imidomethyl sulfonate, 1,8-naphthalenedicarboxylic acid imidotosyl sulfonate, 1,8-naphthalenedicarboxylic acid imide trifluoromethyl sulfonate, 1,8-naphthalenedicarboxylic acid imide camphor sulfonate, succinimide phenyl sulfonate, succinic acid Imidosyl sulfonate, succinimide trifluoromethyl sulfonate, succinimide camphor sulfonate, phthalic imide trifluorosulfonate, cis-5-norbornene-endo-2,3-dicarboxylic acid imide trifluoromethyl sulfonate, benzoin tosylate, 1 , 2-Diphenyl-2-hydroxypropyl tosylate, 1,2-di (4-methylmercaptophenyl) -2-hydroxypropyl tosylate , Pyrogallol methyl sulfonate, pyrogallol ethyl sulfonate, 2,6-dinitrophenyl methyl tosylate, ortho-nitrophenyl methyl tosylate, para-nitrophenyl tosylate and the like. These photoacid generators can be used singly or in combination of two or more.

Among these photoacid generators, (4-n-decyloxyphenyl) phenyliodonium is used as a photoacid generator for curing epoxy compounds, hydrolyzable silane compounds, and condensates of hydrolyzable silane compounds. Most preferred is hexafluoroantimonate. In this case, the curing rate can be further improved by using (4-n-decyloxyphenyl) phenyliodonium hexafluoroantimonate.

  The amount of the photoacid generator added is not particularly limited as long as the curing reaction proceeds sufficiently, but is usually 0.1 to 15 parts by weight, preferably 1 to 10 parts per 100 parts by weight of the binder (B). A part by weight is desirable. When the addition amount of the photoacid generator is less than the above lower limit, the curing reaction of the binder (B) does not proceed sufficiently, and a retardation film having sufficient hardness may not be obtained. Moreover, when the addition amount of a photo-acid generator exceeds the said upper limit, the weather resistance and heat resistance of the phase difference film obtained may fall.

(Iii) Photopolymerization initiator (photo radical generator):
In the present invention, it is preferable to use a photopolymerization initiator (photo radical generator) when curing the acrylate compound. Specific examples of the photopolymerization initiator (photo radical generator) include 1-hydroxycyclohexyl phenyl ketone, 2,2′-dimethoxy-2-phenylacetophenone, xanthone, fluorene, fluorenone, benzaldehyde, anthraquinone, triphenylamine, and carbazole. 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoylpropyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl)- 2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxyl , 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethyl Amino-1- (4-morpholinophenyl) butan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methylpropan-1-one and the like can be mentioned. These photopolymerization initiators (photo radical generators) can be used alone or in combination of two or more.

  Of these photopolymerization initiators (photo radical generators), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide 1-hydroxycyclohexyl phenyl ketone is preferred.

  Moreover, a commercial item can be used for such a photoinitiator (photoradical generator). For example, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one is Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.), and 1-hydroxycyclohexyl phenyl ketone is It can be obtained as Irgacure 184 (manufactured by Ciba Specialty Chemicals).

  The addition amount of the photopolymerization initiator (photo radical generator) is not particularly limited as long as the curing reaction proceeds sufficiently, but is usually 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder (B). The amount is preferably 0.5 to 10 parts by weight. When the addition amount of the photopolymerization initiator (photo radical generator) is less than the lower limit, the curing reaction of the binder (B) does not proceed sufficiently, and a retardation film having sufficient hardness may not be obtained. Moreover, when the addition amount of a photoinitiator (photoradical generator) exceeds the said upper limit, the storage stability of the composition for phase-difference film formation may fall.

(D) Organic solvent:
In the present invention, it is preferable to use the binder (B) by dissolving it in an organic solvent (D). Such an organic solvent (D) can be appropriately determined depending on the dispersion stability of the inorganic particles (A), the solubility of the binder (B) and the curing initiator (C), the coating film thickness or the coating environment. Specific examples of the organic solvent (D) include ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetyl acetone; alcohols such as methanol, ethanol, isopropyl alcohol, n-butanol, and diacetone alcohol; ethyl cellosolve, butyl cellosolve, and propylene Ether group-containing alcohols such as glycol monomethyl ether; hydroxy esters such as methyl lactate, ethyl lactate and butyl lactate; β-ketoesters such as ethyl acetoacetate, methyl acetoacetate and butyl acetoacetate; aromatics such as toluene and xylene And hydrocarbons. These organic solvents (D) can be used individually by 1 type or in mixture of 2 or more types.

  By using such an organic solvent (D), the thickness of the retardation film can be easily controlled, and the obtained retardation film is rich in film thickness uniformity, and further the retardation film of the retardation element. The adhesion between the substrate and the substrate can be increased.

  In addition, when a thermoplastic resin having poor solvent resistance is used as a base material to be described later, smoothness on the surface of the retardation film, suppression of void generation inside the retardation film, and dispersibility and distribution state of fine particles in the retardation film It is preferable to use two or more kinds of solvents having different particle dispersibility and binder solubility in order to appropriately control the thickness and to improve the adhesion between the retardation film and the substrate. Specifically, it comprises a combination of at least one kind of ketone selected from methyl ethyl ketone, methyl isobutyl ketone and the like and at least one kind of alcohol selected from methanol, ethanol, isopropanol, n-butanol, t-butanol and the like. Mixed solvents are preferred.

(E) Additive:
The composition for forming a retardation film according to the present invention includes a photosensitizer, a polymerization inhibitor, a polymerization initiation assistant, a leveling agent, a wettability improver, and a surfactant as long as the object and effects of the present invention are not impaired. Further, additives such as a plasticizer, an ultraviolet absorber, an antioxidant, an antistatic agent, an inorganic filler, a pigment, and a dye can be further contained.

<Method for Preparing Composition for Forming Retardation Film>
The composition for forming a retardation film according to the present invention contains the inorganic particles (A), the binder (B), and, if necessary, a curing initiator (C), an organic solvent (D), and other additives at room temperature or It can prepare by mixing using mixers, such as a mixer, a kneader, a ball mill, and a 3 rolls, on heating conditions. In the case of mixing under heating conditions, it is preferable to carry out the reaction at a temperature or lower where reaction such as binder (B) and curing initiator (C) and alteration such as decomposition do not occur.

  The composition for forming a retardation film has a viscosity of usually 1 to 10,000 mPa · s, preferably 2 to 1,000 mPa · s, and more preferably 3 to 100 mPa · s. A retardation film can be formed and its film thickness can be easily controlled. As a result, a retardation film that expresses a desired retardation, that is, a retardation film having a desired retardation value can be easily obtained. In addition, a retardation film excellent in transparency and stability can be easily obtained. Here, the phase difference value means a retardation value defined by the product (Δnd) of the refractive index difference (Δn) of the birefringent light and the film thickness (d).

<Phase difference film>
The retardation film according to the present invention can be formed by applying (coating) the composition for forming a retardation film to a support such as a substrate described later, and drying and / or curing.

  The coating method is not particularly limited, and examples include dipping method, spray method, bar coating method, roll coating method, spin coating method, curtain coating method, gravure printing method, silk screen method, and ink jet method.

  When the retardation film forming composition contains an organic solvent (D), it is preferable to put a drying step (solvent removing step) for removing the organic solvent (D) before the curing step described later. . For example, the organic solvent (D) can be removed by evaporating the organic solvent (D) by applying (coating) the retardation film-forming composition to a substrate or the like and then putting it in a hot air dryer or a vacuum dryer. The drying temperature at this time is preferably lower than the temperature (bp + 100 ° C.) higher by 100 ° C. than the boiling point (bp) of the organic solvent (D), more preferably from the temperature (bp + 50 ° C.) higher by 50 ° C. than the boiling point (bp). At a lower temperature, particularly preferably a temperature lower than the temperature (bp + 20 ° C.) 20 ° C. higher than the boiling point (bp), most preferably a temperature lower than the boiling point. At this time, when a plurality of types of solvents are used, it is preferable that the drying temperature satisfy the above range for the solvent having the lowest boiling point (bp). Moreover, the preferable processing time of a drying process is 0.01 second-60 minutes, More preferably, it is 1 second-30 minutes, Most preferably, they are 1 minute-30 minutes. The amount of the organic solvent (D) remaining after the solvent removal step and before the curing step described later is preferably 10% by weight or less, more preferably 5% by weight or less, and particularly preferably 1% by weight or less. By removing the organic solvent (D) by the above method and setting the residual amount in the above range, the formation of bubbles in the finally obtained retardation film is prevented and the inorganic particles (A) and the binder (B) In addition, the arrangement of the inorganic particles (A) in the retardation film is more favorable for developing birefringence. Further, the scratch resistance, transparency and solvent resistance of the obtained retardation film and the adhesion between the retardation film and the substrate are further improved, and the durability stability of these characteristics is further improved.

  The method of curing the composition for forming a retardation film applied to a substrate or the like is not particularly limited as long as the effects of the present invention are not impaired, and a high energy beam such as an electron beam is used without using a curing initiator. Although it may be cured by irradiation, it is usually preferable to use a curing initiator because it cures more reliably.

When a photoacid generator or a photopolymerization initiator is used as a curing initiator, it is photocured by irradiation with ultraviolet rays or visible light. In this case, the exposure amount is usually 0.01 to 10 J / cm ² , preferably Is 0.1 to 5 J / cm ² , more preferably 0.3 to 3 J / cm ² . When the exposure amount is less than the lower limit, curing failure may occur. When the exposure amount exceeds the upper limit, the curing time becomes excessively long and the substrate may be deteriorated.

  Moreover, when using a thermal acid generator and a thermal polymerization initiator as a hardening initiator, hardening temperature is 60-200 degreeC normally, Preferably it is 80-170 degreeC. When the curing temperature is less than the above lower limit, poor curing may occur, and when the curing temperature exceeds the upper limit, the substrate may be altered or deformed by heat.

  In the retardation film formed from the retardation film forming composition by the above method, most of the inorganic particles (A) lie parallel to the film plane, and the major axis direction of the inorganic particles (A) Are parallel to the film plane, but the direction of the major axis direction of the inorganic particles (A) in the film plane is random. That is, most of the inorganic particles (A) only have to have a major axis direction perpendicular to the film thickness direction. Here, “the majority of the inorganic particles (A)” means an amount such that the remaining inorganic particles do not greatly affect the purpose and effect of the present invention.

  As a result, this retardation film has substantially no refractive index difference in the film plane direction (x direction, y direction, where the x direction and y direction are orthogonal), but the film plane direction and the film thickness direction. A difference in refractive index occurs between (z direction) and the refractive index in the film plane direction becomes larger than the refractive index in the film thickness direction.

  By the way, it is preferable that the component formed by the binder (B) in the retardation film is optically isotropic because its molecular chain is not substantially oriented. Here, “substantially oriented molecular chains” means that “the molecular chains constituting the component formed by the binder (B) are oriented with a certain degree of regularity and the birefringence of the retardation film. It means “orientation that exhibits birefringence to such a degree as to have a large effect”. Although it is difficult to measure the birefringence of only the component formed by the binder (B) in the retardation film, the birefringence is to some extent by forming a film by curing only the binder (B). Can be guessed. The difference in refractive index in the x, y, and z directions measured in this manner is preferably 0.001 or less, more preferably 0.0005 or less, and particularly preferably 0.0001 or less. When the birefringence of the component formed by the binder (B) in the retardation film is large, desired retardation characteristics may not be obtained.

In the retardation film according to the present invention, the difference (Δn _f ) between the refractive index in the film plane direction and the refractive index in the film thickness direction is usually 0.010 or more, preferably 0.020 or more, more preferably 0.030. That's it. When Δn _f is in the above range, the retardation film exhibits excellent birefringence, and a retardation can be satisfactorily expressed in transmitted light in the film thickness direction.

The thickness of the retardation film is not particularly limited, but is usually 50 to 30,000 nm, preferably 50 to 20,000 nm, more preferably 60 to 10,000 nm. If the thickness of the retardation film is less than the above upper limit, sufficient birefringence may not be obtained, and if the thickness of the retardation film exceeds the above upper limit, sufficient transmittance may not be obtained. In addition, the inorganic particles (A) may be improperly arranged in the retardation film, and birefringence may not be obtained. Further, the thickness unevenness of the retardation film is preferably within ± 10%, more preferably within ± 5% with respect to the average film thickness. When the thickness unevenness is in the above range, the retardation film has little unevenness and a good retardation film is obtained.

  The residual solvent amount in the retardation film is preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably 0.5% by weight or less. When the residual solvent amount is in the above range, characteristics such as weather resistance, heat resistance, and birefringence can be expressed well over a long period of time.

(Retardation film having transparent conductive film)
The retardation film according to the present invention may be a retardation film including the retardation film and a transparent conductive film described later. That is, a transparent conductive layer can be laminated on at least one side of the retardation film.

  As a material for forming the transparent conductive layer (transparent conductive film), metals such as Sn, In, Ti, Pb, Au, Pt, and Ag, or oxides thereof are generally used. These simple metal films can be formed on a substrate, and if necessary, this simple metal film can be oxidized to produce a transparent conductive film. In addition, there is a method of depositing as a metal oxide layer from the beginning of the film formation, but at the beginning of the film formation, a film is formed in the form of a single metal or a lower oxide, and thereafter, such as heating oxidation, anodization or liquid phase oxidation It can also be made transparent by oxidation treatment.

  These transparent conductive films may be formed by adhering a sheet, film or the like having another transparent conductive layer to the retardation film. Plasma polymerization method, sputtering method, vacuum deposition method, plating, ion plating method Alternatively, it may be formed directly on the retardation film by spraying, electrolytic deposition, or the like. The thickness of these transparent conductive films is appropriately determined depending on desired characteristics and is not particularly limited, but is usually 10 to 10,000 angstroms, preferably 50 to 5,000 angstroms.

When the transparent conductive layer is directly formed on the retardation film according to the present invention, an adhesive layer and an anchor coat layer may be formed between the retardation film and the transparent conductive film as necessary. The adhesive layer can be formed using a heat-resistant resin such as epoxy resin, polyimide, polybutadiene, phenol resin, or polyetheretherketone. In addition, the anchor coat layer is formed by curing by a known curing method, for example, UV curing or heat curing, using an anchor coating agent including an acrylic prepolymer such as epoxy diacrylate, urethane diacrylate, or polyester diacrylate. Can do.

(Combination of retardation film and antireflection film)
The retardation film according to the present invention may be used by forming an antireflection film on the film. By using the retardation film and the antireflection film in combination, an antireflection effect is obtained and the light transmittance is improved. The composition for forming the antireflection film (hereinafter referred to as “antireflection film forming composition”) is, for example, a fluorinated copolymer having a hydroxyl group and a curable compound having a functional group capable of reacting with the hydroxyl group. It is preferable to contain a thermal acid generator and / or an organic solvent. At this time, the refractive index of the antireflection film is preferably adjusted within a range of ± 10% from the value of the square root of the product of the refractive index in the film thickness direction of the retardation film and the refractive index of the medium such as a substrate in contact therewith, More preferably, it is adjusted within the range of ± 5% from this square root value. The light transmittance can be further improved by adjusting the refractive index of the antireflection film within the above range.

(1) Fluorine-containing copolymer having a hydroxyl group:
The fluorine-containing copolymer having a hydroxyl group used in the present invention (hereinafter simply referred to as “fluorine-containing copolymer”) is not particularly limited as long as it is a fluorine-containing copolymer having a hydroxyl group in the molecule, and is preferably used. can do. Specifically, a monomer containing a fluorine atom (hereinafter referred to as “monomer (I)”) and a monomer containing a hydroxyl group or an epoxy group (hereinafter referred to as “monomer (II)”)
Can be obtained by copolymerization. Further, it is preferable to add an ethylenically unsaturated monomer other than the monomer (I) and the monomer (II) (hereinafter referred to as “monomer (III)”) as necessary.

Monomers (I) include tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, chlorotrifluoroethylene, trifluoroethylene, tetrafluoroethylene, (fluoroalkyl) vinyl ether, (fluoroalkoxyalkyl) vinyl ether, perfluoro ( Alkyl vinyl ether), perfluoro (alkoxy vinyl ether), fluorine-containing (meth) acrylic acid ester, and the like. These monomers (I
) Can be used singly or in combination of two or more.

The blending amount of the monomer (I) in the production of the fluorine-containing copolymer is not particularly limited, but is usually 10 to 99 mol%, preferably 15 to 97 mol%.

  Monomers (II) include hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, hydroxyhexyl vinyl ether, hydroxyethyl allyl ether, hydroxybutyl allyl ether, glycerol monoallyl ether, allyl alcohol, hydroxyethyl ( And (meth) acrylic acid esters. These monomers (II) can be used alone or in combination of two or more.

  The blending amount of the monomer (II) in the production of the fluorine-containing copolymer is not particularly limited, but is usually 1 to 20 mol%, preferably 3 to 15 mol%.

Examples of the monomer (III) include methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, and octyl vinyl ether. These monomers (III) can be used alone or in combination of two or more.

The blending amount of the monomer (III) in the production of the fluorine-containing copolymer is not particularly limited, but is usually 5 to 45 mol%, preferably 10 to 40 mol%.

  The degree of polymerization of the fluorine-containing copolymer is appropriately determined in consideration of the mechanical strength and coating properties of the antireflection film. For example, the intrinsic viscosity (using N, N-dimethylacetamide solvent, measuring temperature 25 ° C.) affecting the mechanical strength and coating properties is usually 0.05 to 2.0 dl / g, preferably 0.1 to 1. It is preferable to adjust the degree of polymerization so as to be 5 dl / g. When the intrinsic viscosity is in the above range, the obtained antireflection film exhibits excellent mechanical strength and applicability.

  The polymerization method of the fluorine-containing copolymer is not particularly limited, and examples thereof include a solution polymerization method using a radical polymerization initiator, a suspension polymerization method, an emulsion polymerization method, and a bulk polymerization method.

(2) A curable compound having a functional group capable of reacting with a hydroxyl group:
As the curable compound having a functional group capable of reacting with a hydroxyl group used in the present invention (hereinafter also referred to as “curable compound for antireflection film”), a melamine compound, a urea compound, a guanamine compound, a phenol compound, an epoxy compound, An isocyanate compound, a polybasic acid, etc. are mentioned. These compounds can be used individually by 1 type or in combination of 2 or more types.

  Among these compounds, by using the same type of compound as the binder (B) in the composition for forming a retardation film, the compatibility between the retardation film and the antireflection film is improved, and further excellent transmittance and Adhesion can be obtained.

  Of the curable compounds for antireflection films, melamine compounds having two or more methylol groups and alkoxylated methyl groups or the above substituents in the molecule are preferred. By using such a melamine melamine compound, the composition for forming an antireflection film is excellent in storage stability and can be cured at a low temperature. Among such melamine compounds, methylated melamine compounds such as hexamethyletherified methylolmelamine compounds, hexabutyletherified methylolmelamine compounds, methylbutyl mixed etherified methylolmelamine compounds, methyletherified methylolmelamine compounds, butyletherified methylolmelamine compounds, More preferred.

  In the present invention, a compound having a functional group capable of reacting with the binder (B) of the composition for forming a retardation film and a photopolymerizable functional group can also be used as the curable compound for the antireflection film.

  The addition amount of the curable compound for antireflection film is preferably 1 to 70 parts by weight with respect to 100 parts by weight of the fluorinated copolymer. When the addition amount of the curable compound for antireflection film is less than 1 part by weight, curing of the fluorine-containing copolymer having a hydroxyl group may be insufficient, and when it exceeds 70 parts by weight, the composition for forming an antireflection film Storage stability of the product may be reduced.

(3) Thermal acid generator:
The thermal acid generator used in the present invention is not particularly limited as long as the curing reaction of the composition for forming an antireflection film sufficiently proceeds. For example, the thermal acid generator used for the composition for forming a retardation film is used. The same thing as an agent is mentioned.

The addition amount of the thermal acid generator is not particularly limited, but is usually 0.1 to 30 weights with respect to 100 parts by weight of the total amount of the fluorine-containing copolymer and the curable compound for antireflection film. Parts, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight. When the addition amount of the thermal acid generator is less than the above lower limit, the effect of adding the thermal acid generator may not be exhibited, and when the addition amount of the thermal acid generator exceeds the above upper limit, Storage stability may be reduced.

(4) Organic solvent:
As the organic solvent used in the present invention, it is preferable to use the same organic solvent as the organic solvent (D) used in the composition for forming a retardation film.

  The addition amount of the organic solvent is preferably 100 to 10,000 parts by weight with respect to 100 parts by weight of the fluorine-containing copolymer. When the addition amount of the organic solvent is less than 100 parts by weight, it may be difficult to form an antireflection film having a uniform thickness, and when it exceeds 10,000 parts by weight, the composition for forming an antireflection film The storage stability of may decrease.

<Phase difference element>
The retardation element according to the present invention has the retardation film. The retardation element may be formed by using a retardation film obtained by drying and / or curing the retardation film forming composition alone, and the retardation film is formed on a substrate. You may form using the film | membrane (retardation film) which apply | coated (coating) the forming composition and dried and / or hardened | cured.

  The retardation element according to the present invention may further have a transparent conductive film. This transparent conductive film may be directly formed on the surface of the retardation film, or may be formed at a location other than the base material or other retardation film. Here, the retardation film is as described above.

  Further, in the retardation element according to the present invention, a transparent conductive layer can be laminated on at least one surface thereof as in the above-described retardation film, and at this time, an adhesive layer and an anchor coat layer can be formed.

<Base material>
The base material is not particularly limited as long as it does not impair the object and effect of the present invention, and the material and shape can be appropriately selected according to desired characteristics. For example, a transparent inorganic compound such as glass or quartz, a transparent plastic sheet or film can be used as the substrate. Moreover, you may use a lens or a prism-shaped molded article as a base material. Furthermore, a reflective base material can also be used. When the retardation film is formed on a reflective substrate, the phase difference of reflected light can be controlled. Among such substrates, it is preferable to use a transparent film generally used as an optical film as a substrate in consideration of productivity.

  In addition, a film such as a uniaxially stretched film or a biaxially stretched film, to which optical properties such as birefringence are suitably imparted, for example, a retardation film can also be used.

  It is desirable that the thickness of the base material is normally within ± 20%, preferably within ± 10%, more preferably within ± 5%, particularly preferably within ± 3% with respect to the average value. When the thickness distribution of the base material is within the above range, the birefringence unevenness (position) is present even when the film comprising the retardation film and the base material is stretched and oriented after the retardation film forming composition is applied. Phase difference) can be prevented.

Such a substrate can be obtained from, for example, glass, polycarbonate resin, polyester resin, acrylic resin, triacetyl acetate resin (TAC), or cyclic olefin resin such as norbornene resin. By using a retardation element including a substrate made of these resins, an excellent display effect can be obtained in the field of application of a retardation film for liquid crystal display and a viewing angle compensation film. Among the above-mentioned resins, when using a base material made of a resin having relatively low heat resistance such as acrylic resin or triacetyl acetate resin (TAC), the retardation film is formed by photocuring rather than thermal curing. It is preferable. By forming the retardation film by photocuring, an excellent display effect can be obtained even if the substrate is made of a resin having poor heat resistance.

  Moreover, you may use such a base material after surface-treating. As the surface treatment method, the surface of the substrate is generally treated by a hydrophilic treatment method, for example, a method of laminating an acrylic resin or a sulfonate group-containing resin by coating or lamination, or a corona discharge treatment or plasma treatment. And the like, and the like.

In the present invention, among the above-mentioned substrates, a substrate obtained from a cyclic olefin resin is particularly preferably used. Examples of the cyclic olefin-based resin include the following (co) polymers. (1) A ring-opening polymer of a polycyclic monomer represented by the following general formula (1).
(2) A ring-opening copolymer of a polycyclic monomer and a copolymerizable monomer represented by the following general formula (1).
(3) A hydrogenated (co) polymer of the ring-opening (co) polymer of (1) or (2) above.
(4) A (co) polymer obtained by cyclization of the ring-opening (co) polymer of the above (1) or (2) by Friedel-Craft reaction and then hydrogenation.
(5) A saturated copolymer of a polycyclic monomer represented by the following general formula (1) and an unsaturated double bond-containing compound.
(6) Addition type of one or more monomers selected from polycyclic monomers represented by the following general formula (1), vinyl cyclic hydrocarbon monomers and cyclopentadiene monomers (co-polymers) ) A polymer and its hydrogenated (co) polymer.
(7) An alternating copolymer of a polycyclic monomer represented by the following general formula (1) and an acrylate.

(Wherein, R ¹ to R ⁴ are each a hydrogen atom, a halogen atom, a hydrocarbon group, or other monovalent organic group, having 1 to 30 carbon atoms, which may be the same or different from each .R ¹ And R ² or R ³ and R ⁴ may be combined to form a divalent hydrocarbon group. R ¹ or R ² and R ³
Alternatively, R ⁴ may be bonded to each other to form a monocyclic or polycyclic structure. m is 0 or a positive integer, and p is 0 or a positive integer. )
[Ring-opening (co) polymer]
(Polycyclic monomer)
Specific examples of the polycyclic monomer include the following compounds, but the present invention is not limited to these specific examples.
Bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] -8-decene,
Tricyclo [4.4.0.1 ^2,5 ] -3-undecene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
Pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] -4-pentadecene,
5-methylbicyclo [2.2.1] hept-2-ene,
5-ethylbicyclo [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 [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-propoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-isopropoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-butoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-ethylidenebicyclo [2.2.1] hept-2-ene,
8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
5-phenylbicyclo [2.2.1] hept-2-ene,
8-phenyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -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 [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-difluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, 8-pentafluoroethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-tris (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrafluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9,9-tetrakis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8-difluoro-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-trifluoromethoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,8,9-trifluoro-9-pentafluoropropoxytetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-fluoro-8-pentafluoroethyl-9,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-difluoro-8-heptafluoroiso-propyl-9-trifluoromethyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-chloro-8,9,9-trifluorotetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8,9-dichloro-8,9-bis (trifluoromethyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,
5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8- (2,2,2-trifluoroethoxycarbonyl) tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene.

  These can be used individually by 1 type or in combination of 2 or more types.

Among the polycyclic monomers, preferred are those in the general formula (1) wherein R ¹ and R ³ are hydrogen atoms or 1 to 10 carbon atoms, more preferably 1 to 4, particularly preferably 1 to 2. R ² and R ⁴ are hydrogen atoms or monovalent organic groups, and at least one of R ² and R ⁴ represents a polar group having a polarity other than hydrogen atoms and hydrocarbon groups , M is an integer of 0-3, p is an integer of 0-3, more preferably m + p = 0-4, more preferably 0-2, particularly preferably m = 1, p = 0. . The polycyclic monomer in which m = 1 and p = 0 is preferable in that the obtained cyclic olefin-based resin has a high glass transition temperature and excellent mechanical strength.

  Examples of the polar group of the polycyclic monomer include a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, an allyloxycarbonyl group, an amino group, an amide group, and a cyano group. These polar groups are linked to a methylene group or the like. It may be bonded via a group. In addition, a hydrocarbon group in which a divalent organic group having a polarity such as a carbonyl group, an ether group, a silyl ether group, a thioether group, or an imino group is bonded as a linking group can also be exemplified. Among these, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or an allyloxycarbonyl group is particularly preferable.

Furthermore, a monomer in which at least one of R ² and R ⁴ is a polar group represented by the chemical formula — (CH ₂ ) _n COOR is obtained by using a cyclic olefin-based resin having a high glass transition temperature, low hygroscopicity, It is preferable at the point which has the outstanding adhesiveness with material. In the above chemical formula, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms, and preferably an alkyl group. In addition, n is usually 0 to 5, but the smaller the value of n, the higher the glass transition temperature of the obtained cyclic olefin-based resin, which is preferable. Further, n is 0. The body is preferred because it is easy to synthesize.

In the general formula (1), R ¹ or R ³ is preferably an alkyl group, preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 to 2 carbon atoms, particularly preferably a methyl group. In addition, the hygroscopic property of the resulting cyclic olefin-based resin that the alkyl group is bonded to the same carbon atom as the carbon atom to which the polar group represented by the chemical formula — (CH ₂ ) _n COOR is bonded. Is particularly preferable in that it can be lowered.

(Copolymerizable monomer)
Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene. As carbon number of a cycloolefin, 4-20 are preferable, More preferably, it is 5-12. These can be used individually by 1 type or in combination of 2 or more types.

  A preferred ratio of the polycyclic monomer and the copolymerizable monomer (polycyclic monomer / copolymerizable monomer) is 100/0 to 50/50 by weight, and more preferably. Is 100/0 to 60/40.

(Catalyst for ring-opening polymerization)
In the present invention, (1) a ring-opening polymer of the polycyclic monomer, and (2) a ring-opening copolymer of the polycyclic monomer and a copolymerizable monomer are obtained. The ring polymerization reaction is performed in the presence of a metathesis catalyst.

This metathesis catalyst is
(A) at least one compound selected from compounds having W, Mo and Re (hereinafter referred to as compound (a));
(B) Deming periodic table group IA elements (for example, Li, Na, K, etc.), group IIA elements (for example, Mg, Ca, etc.), group IIB elements (for example, Zn, Cd, Hg, etc.), group IIIA elements (For example, B, Al, etc.), a compound having a group IVA element (for example, Si, Sn, Pb, etc.), or a group IVB element (for example, Ti, Zr, etc.), The catalyst comprises a combination of at least one compound selected from compounds having at least one bond between this element and hydrogen (hereinafter referred to as compound (b)). Further, in order to enhance the activity of the catalyst, an additive (c) described later may be further added.

Examples of the compound (a) include WCl ₆ , MoCl ₆ , ReOCl ₃ and the like.
No. 26, page 8, lower left column, line 6 to page 8, upper right column, line 17 can be mentioned.

As the compound _{(b), n-C 4} H 9 Li, (C 2 H 5) 3 Al, (C 2 H 5) 2 AlCl, (C 2 H 5) 1.5 AlCl 1.5, (C 2 H 5) AlCl ₂ , compounds such as methylalumoxane, LiH and the like, described in JP-A No. 1-132626, page 8, upper right column, line 18 to page 8, lower right column, line 3.

  As the additive (c) component, alcohols, aldehydes, ketones, amines and the like can be suitably used. JP-A-1-132626, page 8, lower right column, lines 16 to 9 The compounds shown in the upper left column, line 17 can also be used.

  The amount of the metathesis catalyst used is such that the molar ratio of the compound (a) to the polycyclic monomer (compound: polycyclic monomer) is usually from 1: 500 to 1: 50,000, preferably 1. : The quantity used as 1,000-1: 10,000 is preferable.

  The ratio of compound (a) to compound (b) (compound (a): compound (b)) is 1: 1 to 1:50, preferably 1: 2 to 1:30 in terms of metal atom ratio.

  The ratio of compound (a) to compound (c) (compound (c): compound (a)) is 0.005: 1 to 15: 1, preferably 0.05: 1 to 7: 1 in molar ratio. desirable.

(Solvent for polymerization reaction)
Examples of the solvent used in the ring-opening polymerization reaction include alkanes such as pentane, hexane, heptane, octane, nonane, decane; cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane; benzene, toluene, xylene Aromatic hydrocarbons such as chlorobutane, bromohexane, methylene chloride, dichloroethane, hexamethylene dibromide, chloroform, tetrachloroethylene; aryl halide compounds such as chlorobenzene; ethyl acetate, n-butyl acetate , Saturated carboxylic acid esters such as iso-butyl acetate, methyl propionate and dimethoxyethane; ethers such as dibutyl ether, tetrahydrofuran and dimethoxyethane Kind, and the like. These can be used alone or in admixture of two or more. Of these, aromatic hydrocarbons are preferred. Such a solvent is used as a solvent for dissolving the solvent constituting the molecular weight regulator solution, the polycyclic monomer and / or the metathesis catalyst.

  The amount of the solvent used is such that the weight ratio of the solvent to the polycyclic monomer (solvent: polycyclic monomer) is usually 1: 1 to 10: 1, preferably 1: 1 to 5: 1. Is desirable.

(Molecular weight regulator)
The molecular weight of the resulting ring-opening (co) polymer can be adjusted by the polymerization temperature, the type of catalyst, and the type of solvent, but can also be adjusted by allowing a molecular weight regulator to coexist in the reaction system. .

  Suitable molecular weight regulators include, for example, α-olefins such as ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, and styrene. Of these, 1-butene and 1-hexene are particularly preferred. These molecular weight regulators can be used alone or in admixture of two or more.

  The amount of the molecular weight regulator used is usually 0.005 to 0.6 mol, preferably 0.02 to 0.5 mol, per 1 mol of the polycyclic monomer subjected to the ring-opening polymerization reaction. is there.

(Unsaturated hydrocarbon polymer)
The ring-opening copolymer can be obtained by ring-opening polymerization of the polycyclic monomer and the copolymerizable monomer in a ring-opening copolymerization reaction to be described later, such as polybutadiene and polyisoprene. In the presence of unsaturated hydrocarbon polymers such as conjugated diene compounds, styrene-butadiene copolymers, ethylene-nonconjugated diene copolymers, polynorbornene, etc. that contain two or more carbon-carbon double bonds in the main chain. Polycyclic monomers may be subjected to ring-opening polymerization.

(Ring-opening (co) polymerization reaction)
The method for producing the ring-opening copolymer can use a known ring-opening polymerization reaction for a cyclic olefin, and the polycyclic monomer and the copolymerizable monomer are converted into the catalyst for ring-opening polymerization. It can be produced by ring-opening polymerization in the presence of a solvent for polymerization reaction, and if necessary, the molecular weight regulator.

[Hydrogenated (co) polymer]
The ring-opening (co) polymer obtained by the above method may be used as it is, or may be used as a hydrogenated (co) polymer obtained by hydrogenation thereof. This hydrogenated (co) polymer is useful as a raw material for resins having high impact resistance.

  In the hydrogenation reaction, a hydrogenation catalyst is added to a usual method, that is, a solution of a ring-opening (co) polymer, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm, is added to 0 to 200 ° C., Preferably it is performed by operating at 20 to 180 ° C.

  Thus, by hydrogenation, the resulting hydrogenated (co) polymer has excellent thermal stability, and its properties deteriorate even when heated during molding or as a product. There is nothing.

  The hydrogenation rate of the hydrogenated (co) polymer is usually 50% or more, preferably 70% or more, more preferably 90% or more, particularly preferably 98% or more, most preferably measured by 500 MHz and 1H-NMR. 99% or more. The higher the hydrogenation rate, the better the stability to heat and light. When used as a base material for a retardation element, stable characteristics can be obtained over a long period of time.

  The hydrogenated (co) polymer used as the cyclic olefin-based resin preferably has a gel content contained in the hydrogenated (co) polymer of 5% by weight or less, particularly 1% by weight or less. It is preferable that

(Hydrogenation catalyst)
As a hydrogenation catalyst, what is used for the hydrogenation reaction of a normal olefinic compound can be used. Examples of the hydrogenation catalyst include a heterogeneous catalyst and a homogeneous catalyst.

  Examples of the heterogeneous catalyst include a solid catalyst in which a noble metal catalyst material such as palladium, platinum, nickel, rhodium, and ruthenium is supported on a carrier such as carbon, silica, alumina, and titania. Homogeneous catalysts include nickel naphthenate / triethylaluminum, nickel acetylacetonate / triethylaluminum, cobalt octenoate / n-butyllithium, titanocene dichloride / diethylaluminum monochloride, rhodium acetate, chlorotris (triphenylphosphine) rhodium, dichloro Examples thereof include tris (triphenylphosphine) ruthenium, chlorohydrocarbonyltris (triphenylphosphine) ruthenium, dichlorocarbonyltris (triphenylphosphine) ruthenium, and the like. The form of the catalyst may be powder or granular.

In these hydrogenation catalysts, the weight ratio of the ring-opening (co) polymer to the hydrogenation catalyst (ring-opening (co) polymer: hydrogenation catalyst) is 1: 1 × 10 ⁻⁶ to 1: 2. Used in proportions.

(Cyclization by Friedel-Craft reaction)
As the hydrogenated (co) polymer, one obtained by hydrogenating the ring-opened (co) polymer as described above may be used, but the ring-opened (co) polymer may be circulated by Friedel-Craft reaction. Then, a hydrogenated (co) polymer can be used.

The method for cyclizing the ring-opened (co) polymer by Friedel-Craft reaction is not particularly limited, but a known method using an acidic compound described in JP-A No. 50-154399 can be employed. . Specific examples of the acidic compound include AlCl ₃ , BF ₃ , FeCl ₃ , A
Lewis acids such as l ₂ O ₃ , HCl, CH ₃ ClCOOH, zeolite, activated clay, and Bronsted acid are used. The cyclized ring-opening (co) polymer can be hydrogenated by the same method as the hydrogenation reaction of the ring-opening (co) polymer.

[Saturated copolymer]
As the cyclic olefin-based resin, a saturated copolymer of the polycyclic monomer and an unsaturated double bond-containing compound can also be used. This saturated copolymer can be obtained by a usual addition polymerization reaction using a catalyst.

(Unsaturated double bond-containing compound)
Examples of the unsaturated double bond-containing compound include olefinic compounds having preferably 2 to 12 carbon atoms, more preferably 2 to 8 carbon atoms, such as ethylene, propylene, and butene.

  A preferred weight ratio of the polycyclic monomer to the unsaturated double bond-containing compound (the polycyclic monomer / unsaturated double bond-containing compound) is 90/10 to 40/60, Preferably it is 85 / 15-50 / 50.

(Addition polymerization catalyst)
As the addition polymerization catalyst, at least one compound selected from a titanium compound, a zirconium compound and a vanadium compound, and an organoaluminum compound as a co-catalyst are used.

  Examples of the titanium compound include titanium tetrachloride and titanium trichloride. Examples of the zirconium compound include bis (cyclopentadienyl) zirconium chloride and bis (cyclopentadienyl) zirconium dichloride.

As a vanadium compound, the following formula
VO (OR) _a X _b or V (OR) _c X _d
(Wherein R is a hydrocarbon group, X is a halogen atom, and 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, 2 ≦ (a + b) ≦ 3, 0 ≦ c ≦ 4, 0 ≦ d ≦ 4, (3 ≦ (c + d) ≦ 4)
The vanadium compound represented by these, or these electron donor adducts are used.

  Examples of the electron donor include oxygen-containing electron donors such as alcohols, phenols, ketones, aldehydes, carboxylic acids, esters of organic acids or inorganic acids, ethers, acid amides, acid anhydrides, alkoxysilanes; ammonia, amines, Examples thereof include nitrogen-containing electron donors such as nitrile and isocyanate.

  As the promoter, at least one organoaluminum compound selected from compounds containing at least one aluminum-carbon bond or aluminum-hydrogen bond is used.

  In the addition polymerization reaction, for example, when a vanadium compound is used as a catalyst, the ratio of the vanadium compound to the organoaluminum compound is such that the ratio of aluminum atom to vanadium atom (Al / V) is 2 or more, preferably 2 to 50, particularly preferably. 3-20 are desirable.

(Solvent for polymerization reaction and molecular weight adjustment method)
As the solvent for the polymerization reaction used in the addition polymerization reaction, the same solvent as that used in the ring-opening polymerization reaction can be used. Moreover, the molecular weight of the resulting saturated copolymer is usually adjusted using hydrogen.

[Additional (co) polymers and their hydrogenated (co) polymers]
As the cyclic olefin resin, an addition type (co) polymer of at least one monomer selected from the polycyclic monomer, vinyl cyclic hydrocarbon monomer, and cyclopentadiene monomer, and its Hydrogenated (co) polymers can also be used.

(Vinyl cyclic hydrocarbon monomer)
Examples of the vinyl cyclic hydrocarbon monomer include vinyl cyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene; vinyl such as 4-vinylcyclopentane and 4-isopropenylcyclopentane. Vinylated 5-membered hydrocarbon monomers such as cyclopentane monomers; 4-vinylcyclohexene, 4-isopropenylcyclohexene, 1-methyl-4-isopropenylcyclohexene, 2-methyl-4-vinylcyclohexene, Vinylcyclohexene monomers such as 2-methyl-4-isopropenylcyclohexene; vinylcyclohexane monomers such as 4-vinylcyclohexane and 2-methyl-4-isopropenylcyclohexane; styrene, α-methylstyrene, 2- Methylstyrene, 3- Styrenic monomers such as styrene styrene, 4-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 4-phenylstyrene, p-methoxystyrene; d-terpene, 1-terpene, diterpene, d-limonene, 1- Terpene monomers such as limonene and dipentene; vinylcycloheptene monomers such as 4-vinylcycloheptene and 4-isopropenylcycloheptene; 4-vinylcycloheptane, 4-isopropenylcycloheptane and the like And vinyl cycloheptane monomers. Of these, styrene and α-methylstyrene are preferred. These can be used individually by 1 type or in combination of 2 or more types.

(Cyclopentadiene monomer)
Examples of the cyclopentadiene monomer include cyclopentadiene, 1-methylcyclopentadiene, 2-methylcyclopentadiene, 2-ethylcyclopentadiene, 5-methylcyclopentadiene, 5,5-methylcyclopentadiene, and the like. Of these, cyclopentadiene is preferred. These can be used individually by 1 type or in combination of 2 or more types.

(Addition polymerization reaction and hydrogenation reaction)
The addition polymerization reaction of at least one monomer selected from the polycyclic monomer, vinyl cyclic hydrocarbon monomer and cyclopentadiene monomer is the addition polymerization reaction in the above-mentioned saturated copolymer. The same method can be used. The hydrogenated (co) polymer of this addition type (co) polymer can be obtained by the same hydrogenation method as the hydrogenated (co) polymer of the ring-opening (co) polymer described above.

[Alternate copolymer]
As the cyclic olefin resin, an alternating copolymer of the polycyclic monomer and acrylate can also be used. Here, the “alternate copolymer” means a copolymer in which the structural unit derived from the polycyclic monomer always has a structure adjacent to the structural unit derived from acrylate. However, this does not deny a structure in which acrylate-derived structural units are adjacent to each other. That is, it means a copolymer having a structure in which acrylate-derived structural units may be adjacent to each other but structural units derived from the polycyclic monomer are not adjacent to each other.

(Acrylate)
Examples of the acrylate include linear, branched or cyclic alkyl acrylates having 1 to 20 carbon atoms such as methyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate; carbon atoms such as glycidyl acrylate and 2-tetrahydrofurfuryl acrylate. 2-20 heterocyclic group-containing acrylate; benzyl acrylate and other aromatic ring group-containing acrylates such as benzyl acrylate; isobornyl acrylate, dicyclopentanyl acrylate, etc. having a polycyclic structure of 7-30 carbon atoms An acrylate is mentioned.

(Alternating copolymer polymerization method)
In the presence of a Lewis acid, the alternating copolymer of the polycyclic monomer and acrylate is usually the polycyclic monomer with respect to a total amount of 100 mol of the polycyclic monomer and acrylate. Is 30 to 70 mol, acrylate is 70 to 30 mol, preferably 40 to 60 mol of the polycyclic monomer and acrylate is 60 to 40 mol, particularly preferably the polycyclic monomer. Can be obtained by radical polymerization at a ratio of 45 to 55 mol and acrylate of 55 to 45 mol.

  The amount of the Lewis acid is 0.001 to 1 mol per 100 mol of acrylate. Also, a known organic peroxide that generates free radicals or a known azobis-based radical polymerization initiator can be used. The polymerization reaction temperature is usually -20 ° C to 80 ° C, preferably 5 ° C to 60 ° C. Moreover, the same solvent as used for the ring-opening polymerization reaction can be used as the solvent for the polymerization reaction.

The cyclic olefin resin used in the present invention has an intrinsic viscosity [η] _inh of 0.2 to 5 dl /
g, more preferably 0.3 to 3 dl / g, particularly preferably 0.4 to 1.5 dl / g, and the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is 8. 1,000 to 100,000, more preferably 10,000 to 80,000, particularly preferably 12,000 to 50,000, and a weight average molecular weight (Mw) of 20,000 to 300,000, more preferably 30. From 50,000 to 250,000, particularly preferably from 40,000 to 200,000 is preferred. When the intrinsic viscosity [η] _inh , number average molecular weight and weight average molecular weight are in the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties of the cyclic olefin resin and the film of the cyclic olefin resin are determined. The balance with the stability of the phase difference of transmitted light when used as a base material of a phase difference element becomes good.

  The glass transition temperature (Tg) of the cyclic olefin-based resin is usually 100 ° C. or higher, preferably 120 to 350 ° C., more preferably 130 to 250 ° C., and particularly preferably 140 to 200 ° C. When Tg is less than the above lower limit, a change in optical characteristics of the obtained retardation element may be increased due to heat from the light source and other adjacent components. Moreover, when Tg exceeds the said upper limit, when heating and processing the base material which consists of this cyclic olefin resin to the temperature of Tg vicinity, such as extending | stretching process, possibility that a resin will carry out thermal degradation will become high.

  The saturated water absorption rate at 23 ° C. of the cyclic olefin resin is preferably 0.05 to 2% by weight, more preferably 0.1 to 1% by weight. If the saturated water absorption rate is within this range, the cyclic olefin resin film can be imparted with uniform optical characteristics, and the adhesion between the cyclic olefin resin film and the retardation film is excellent, and it is peeled off during use. In addition, it is excellent in compatibility with an antioxidant and the like, and a large amount of an antioxidant can be added. When the saturated water absorption is less than the above lower limit, the adhesion with the retardation film or other transparent support becomes poor, and peeling easily occurs, and when the upper limit is exceeded, the cyclic olefin resin film absorbs water. Dimensional changes are likely to occur. In addition, said saturated water absorption is a value obtained by immersing in 23 degreeC water for 1 week, and measuring an increase weight according to ASTM D570.

The cyclic olefin-based resin has a photoelastic coefficient (C _P ) of 0 to 100 (× 10 ⁻¹² Pa ⁻¹ ) and a stress optical coefficient (C _R ) of 1,500 to 4,000 (× Those satisfying 10 ⁻¹² Pa ⁻¹ ) can be preferably used. Here, the photoelastic coefficient (C _P ) and the stress optical coefficient (
C _R ) is based on various documents (Polymer Journal, Vol. 27, No. 9, pp 943-950 (1995); Journal of the Japanese Society of Rheology, Vol. 19, No. 2, pp 93-97 (1991); This is a well-known fact that is described in Elastic Experimental Method, Nikkan Kogyo Shimbun, 7th edition of 1975. The former represents the degree of phase difference caused by stress in the glass state of the polymer, while the latter Represents the degree of phase difference due to stress in the flow state.

The large photoelastic coefficient (C _P ) makes it easy to generate a phase difference sensitively to external factors or stress generated from strains generated by freezing strain when the polymer is used in a glass state. It represents that. For example, it means that an unnecessary phase difference is likely to be generated due to a minute stress generated by shrinkage of a material due to a temperature change or a humidity change. From this, it is better that the photoelastic coefficient (C _P ) is as small as possible.

On the other hand, a large stress optical coefficient (C _R ) means that a desired retardation can be obtained with a small stretch ratio when a cyclic olefin resin film is imparted with retardation, or a large retardation is exhibited. There is a great merit that the film can be thinned compared to a film having a small stress optical coefficient (C _R ) when it is easy to obtain a film that can be imparted or when the same retardation is required.

From the above viewpoint, the photoelastic coefficient (C _P ) is preferably 0 to 100 (× 10 ⁻¹² Pa ⁻¹ ), more preferably 0 to 80 (× 10 ⁻¹² Pa ⁻¹ ), and particularly preferably. 0-50 (x1
0 ⁻¹² Pa ⁻¹ ), more preferably 0 to 30 (× 10 ⁻¹² Pa ⁻¹ ), and most preferably 0 to 20 (× 10 ⁻¹² Pa ⁻¹ ). When the photoelastic coefficient (C _P ) exceeds the above upper limit, when used as a base material for a phase difference element, a cyclic olefin type is generated due to stress generated during the formation of a phase difference film or environmental changes during use of the phase difference element Due to the change in birefringence of the resin film, the amount of transmitted light may decrease when used as a retardation element.

The water vapor permeability of the cyclic olefin resin is usually 1 to 400 g / m ² · 24 hr when a film having a thickness of 25 μm is formed under the conditions of 40 ° C. and 90% RH, preferably 5
It is -350g / m < ² > * 24hr, More preferably, it is 10-300g / m < ² > * 24hr. When the water vapor transmission rate is in the above range, the characteristic change due to the moisture content of the adhesive or adhesive when used as the base material of the retardation element and the characteristic change due to the humidity of the environment where the retardation element is used are reduced. It can be avoided.

  The cyclic olefin resin used in the present invention is composed of at least one (co) heavy rigid body among the (co) polymers of (1) to (7) described above. It can be further stabilized by adding an inhibitor, an ultraviolet absorber or the like. Moreover, in order to improve workability, the additive used in conventional resin processings, such as a lubricant, can also be added.

  Examples of the antioxidant include 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. Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone.

  In addition, the cyclic olefin-based resin used in the present invention may use any of the (co) polymers of (1) to (7) described above, but (1) to (7). Two or more kinds of (co) polymers selected from (co) polymers may be blended and used. Blending can be performed by a method of mixing in a pellet state using an extruder or the like, a method of mixing in a solution state, or the like.

  In the present invention, when a cyclic olefin-based resin film is used as the substrate, the cyclic olefin-based resin is used in the form of a film or a sheet by a melt molding method or a solution casting method (solvent casting method). Of these, the solvent casting method is preferred from the viewpoint of good film thickness uniformity and surface smoothness.

  The method for obtaining the cyclic olefin-based resin film by the solvent casting method is not particularly limited, and a known method may be applied. For example, there may be mentioned a method in which the cyclic olefin resin is dissolved or dispersed in a solvent to form a solution with an appropriate concentration, poured onto a suitable carrier, or coated, and then dried and peeled off from the carrier.

  Below, although various conditions of the method of obtaining a cyclic olefin resin film by a solvent cast method are shown, this invention is not limited to these conditions.

When the cyclic olefin-based resin is dissolved or dispersed in a solvent, the concentration of the resin is usually 0.1 to 90% by weight, preferably 1 to 50% by weight, and more preferably 10 to 35% by weight. If the resin concentration is less than the above lower limit, it becomes difficult to ensure the thickness of the film, and problems such as difficulty in obtaining the surface smoothness of the film due to foaming due to solvent evaporation and the like arise. On the other hand, if the concentration exceeds the above upper limit, the solution viscosity becomes too high and the thickness and surface of the cyclic olefin resin film obtained are difficult to be uniform.

  The viscosity of the solution at room temperature is usually 1 to 1,000,000 mPa · s, preferably 10 to 100,000 mPa · s, more preferably 100 to 50,000 mPa · s, and particularly preferably 1,000. ˜40,000 mPa · s.

  Solvents used include aromatic solvents such as benzene, toluene and xylene; cellosolve solvents such as methyl cellosolve, ethyl cellosolve and 1-methoxy-2-propanol; diacetone alcohol, acetone, cyclohexanone, methyl ethyl ketone, 4-methyl Ketone solvents such as 2-pentanone; ester solvents such as methyl lactate and ethyl lactate; cycloolefin solvents such as cyclohexanone, ethylcyclohexanone and 1,2-dimethylcyclohexane; 2,2,3,3-tetrafluoro- Examples thereof include halogen-containing solvents such as 1-propanol, methylene chloride and chloroform; ether solvents such as tetrahydrofuran and dioxane; alcohol solvents such as 1-pentanol and 1-butanol.

Moreover, even if it is a solvent other than the above, the solubility parameter (SP value) is preferably 10 to 30 (MPa ^1/2 ), more preferably 10 to 25 (MPa ^1/2 ), and particularly preferably 15 to 25. If a solvent in the range of (MPa ^1/2 ), most preferably 15 to 20 (MPa ^1/2 ) is used, a cyclic olefin resin film having good surface uniformity and optical properties can be obtained.

The said solvent can be used individually or in mixture of multiple. When mixed and used, the SP value of the mixed solvent is preferably within the above range. The SP value of the mixed solvent can be predicted by the weight ratio of the solvent. For example, when two kinds of solvents (solvent 1 and solvent 2) are mixed, the weight fractions are expressed as W ₁ , W _2, SP value SP value of the mixed solvent with the SP _1, SP ₂ can be calculated by the following equation.

SP value = W ₁ · SP ₁ + W ₂ · SP ₂
As a method for producing a cyclic olefin-based resin film by a solvent casting method, the above solution is used with a die or a coater, a metal drum, a steel belt, a polyester film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), The method of apply | coating on support bodies, such as a Teflon (R) belt, and drying a solvent after that and peeling a film from a support body is mentioned. Alternatively, the solution can be applied to the support by spraying, brushing, roll spin coating, dipping, etc., and then the solvent is dried to peel the film from the support. In addition, thickness, surface smoothness, etc. are controllable by apply | coating repeatedly.

  The drying process of the solvent casting method is not particularly limited and can be carried out by a generally used method, for example, a method of passing through a drying furnace through a large number of rollers. If this occurs, the characteristics of the film are remarkably deteriorated. Therefore, in order to avoid this, it is preferable to make the drying process into a plurality of processes of two or more stages and to appropriately control the temperature or the air volume in each process.

  The amount of residual solvent in the cyclic olefin-based resin film is usually 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably 0.5% by weight or less. When the residual solvent amount exceeds the above upper limit, the change with time of the dimensions of the cyclic olefin-based resin film may become large. In addition, the residual solvent may lower Tg and reduce heat resistance.

  Moreover, in order to perform the extending | stretching process mentioned later suitably, a cyclic olefin resin film may need to contain a trace amount residual solvent. Specifically, in order to obtain a film in which the retardation is stably and uniformly expressed by stretching orientation, the residual solvent amount is usually 10 to 0.1% by weight, preferably 5 to 0.1% by weight, Preferably it may be 1 to 0.1% by weight. By leaving a trace amount of solvent, stretching may be facilitated, and the control of retardation development may be facilitated.

  The thickness of the cyclic olefin resin film is usually 1 to 500 μm, preferably 10 to 300 μm, and more preferably 30 to 100 μm. If the thickness of the film is less than the above lower limit, handling becomes substantially difficult. Moreover, when the thickness of the film exceeds the above upper limit, it becomes difficult to wind in a roll shape, and the light transmittance may be lowered.

  The cyclic olefin resin film used as the base material of the retardation element can also be used as a retardation film, and a cyclic olefin resin film obtained by the above method is preferably used. Specifically, it can be produced by a known uniaxial stretching method or biaxial stretching method. That is, a horizontal uniaxial stretching method using a tenter method, a compression stretching method between rolls, a longitudinal uniaxial stretching method using rolls with different circumferences, a biaxial stretching method combining a horizontal uniaxial and a longitudinal uniaxial, a stretching method using an inflation method, etc. Can be used.

  In the case of the uniaxial stretching method, the stretching speed is usually 1 to 5,000% / minute, preferably 50 to 1,000% / minute, more preferably 100 to 1,000% / minute, Preferably, it is 100 to 500% / min.

  In the biaxial stretching method, there are a method of simultaneously stretching in two directions and a method of stretching in a direction different from the initial stretching direction after uniaxial stretching. In these methods, the intersecting angle of the two stretching axes is usually in the range of 120 to 60 degrees. The stretching speed may be the same or different in each stretching direction, and is usually 1 to 5,000% / min, preferably 50 to 1,000% / min, more preferably 100 to 1,000% / min, particularly preferably 100 to 500% / min.

  The stretching temperature is not particularly limited, but is usually Tg ± 30 ° C., preferably Tg ± 10 ° C., more preferably Tg-5, based on the glass transition temperature (Tg) of the above-mentioned cyclic olefin resin. It is the range of -Tg + 10 degreeC. When the stretching temperature is within the above range, the occurrence of unevenness in retardation can be suppressed, and the control of the refractive index ellipsoid is facilitated.

  The draw ratio is not particularly limited because it is determined by the desired properties, but is usually 1.01 to 10 times, preferably 1.1 to 5 times, and more preferably 1.1 to 3 times. When the draw ratio exceeds 10 times, it may be difficult to control the phase difference.

  The stretched film may be cooled as it is, but it is allowed to stand in a temperature atmosphere of Tg-20 ° C. to Tg for at least 10 seconds, preferably 30 seconds to 60 minutes, more preferably 1 minute to 60 minutes. preferable. Thereby, the retardation film which consists of a cyclic olefin-type resin film with few retardation changes with time, and stable can be obtained.

The linear expansion coefficient of the cyclic olefin resin film is preferably 1 × 10 ⁻⁴ (1 / ° C.) or less, more preferably 9 × 10 ⁻⁵ (1 / ° C.) in the temperature range of 20 ° C. to 100 ° C. Or less, particularly preferably 8 × 10 ⁻⁵ (1 / ° C.) or less, and most preferably 7 × 10 ⁻⁵ (1 / ° C.) or less. In the case of a retardation film made of a cyclic olefin resin, the difference in linear expansion coefficient between the stretching direction and the direction perpendicular thereto is preferably 5 × 10 ⁻⁵ (1 / ° C.) or less, more preferably 3 × 10. ^-5 (1 / ° C) or less, particularly preferably 1 × 10 ^-5 (1 / ° C) or less. When the linear expansion coefficient is within the above range, when a retardation film made of a cyclic olefin-based resin film is used as a base material for a retardation element, the level of transmitted light affected by changes in stress due to temperature, humidity, etc. during use. It is possible to obtain a retardation element that suppresses a change in phase difference and maintains good adhesion with a retardation film and has stable optical characteristics over a long period of time.

  The film stretched as described above has molecules oriented by stretching and gives a retardation to transmitted light. The retardation imparting performance depends on the retardation value and stretching ratio of the film before stretching. It can be controlled by the temperature and the thickness of the film after stretching orientation.

  When the film before stretching has a certain thickness, the larger the stretching ratio, the larger the absolute value of the retardation. Therefore, the retardation film having a desired retardation value can be obtained by changing the stretching ratio. Can do.

  The retardation value in the film plane with a light wavelength of 590 nm of the retardation film made of the cyclic olefin resin film used in the present invention is preferably 1 to 3,000 nm, more preferably 10 to 1,000 nm, and particularly preferably 50. ~ 500 nm. Further, the thickness direction retardation value is preferably 1 to 1000 nm, more preferably 10 to 500 nm, and particularly preferably 50 to 250 nm.

<Polarizing plate>
The polarizing plate according to the present invention is a polarizing plate obtained by laminating a protective film (a), a polarizing film (b), and a protective film (c) in this order, and the protective film (a) and / or ( c) is a polarizing plate comprising the retardation film or the retardation element. In addition, the polarizing plate according to the present invention can also have a transparent conductive layer laminated on at least one surface thereof, like the above-described retardation film and retardation element, and at this time, an adhesive layer and an anchor coat layer are formed. You can also.

  The polarizing film (b) used in the present invention is, for example, a film made of polyvinyl alcohol (PVA) or a polymer obtained by formalizing a part of PVA with a dichroic substance made of iodine or a dichroic dye. It is a film obtained by performing treatment, stretching treatment, crosslinking treatment, etc. in an appropriate order and method, and is transmitted as linearly polarized light when natural light is incident thereon. In particular, those having a high light transmittance and an excellent degree of polarization are preferably used. In general, the thickness of the polarizing film (b) is preferably 5 to 80 μm, but is not limited to this in the present invention. As the polarizing film (b), in addition to the PVA-based film, other films may be used as long as they exhibit similar characteristics. For example, a film made of a cyclic olefin resin may be subjected to a dyeing process, a stretching process, a crosslinking process, and the like in an appropriate order and method.

  When the retardation film or the retardation element is used for only one of the protective films (a) and (c), the remaining protective film includes transparency, mechanical strength, thermal stability and moisture shielding properties. A film made of a polymer excellent in the above is preferably used. For example, cellulose films such as diacetyl cellulose and triacetyl cellulose (TAC); polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; acrylic resin films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate A polycarbonate film, a polyethersulfone film, a polysulfone film, a polyimide film, a cyclic olefin resin film, and the like can be used. These films can be suitably produced by a solution casting method (casting method) or a melt molding method. Moreover, the thickness of this protective film is 20-250 micrometers normally, Preferably it is 30-100 micrometers.

  Among such films, the protective films (a) and (b) can be further improved from the viewpoint that the polarizing plate can further improve the moisture resistance, heat resistance and optical properties of the polarizing plate, and is excellent in adhesion to the polarizing plate. ) Is preferably used as a film made of a cyclic olefin resin, and it is particularly preferable to use a film made of a cyclic olefin resin for both protective films.

Further, the polarizing plate according to the present invention can further be provided with various functional layers on one side or both sides of the polarizing plate. For example, as a functional layer. Examples thereof include a pressure-sensitive adhesive layer, an antiglare layer, a hard coat layer, an antireflection layer, a half reflection layer, a reflection layer, a phosphorescent layer, a diffusion layer, and an electroluminescence layer. These functional layers can also be installed in combination of two or more layers, and examples thereof include a combination of an antiglare layer and an antireflection layer, a phosphorescent layer and a reflective layer, a phosphorescent layer and a light diffusion layer, and the like. The combination of functional layers is not limited to these.
(Production method of polarizing plate)
The polarizing plate according to the present invention can be produced by bonding the polarizing film (b) and the protective films (a) and (c) by a known method. In the present invention, at least one of the protective films (a) and (c) may be the retardation film or the retardation element. In order to bond the polarizing film (b) and the protective films (a) and (c), an adhesive or an adhesive can be used. As the pressure-sensitive adhesive and adhesive, those having excellent transparency are preferable. Specifically, pressure-sensitive adhesives such as natural rubber, synthetic rubber, vinyl acetate / vinyl chloride copolymer, polyvinyl ether, acrylic resin, modified polyolefin resin, etc. A curable pressure-sensitive adhesive obtained by adding a curing agent such as an isocyanate group-containing compound to the resin having a functional group such as a hydroxyl group or an amino group; a polyurethane-based dry laminate adhesive; a synthetic rubber-based adhesive; an epoxy-based adhesive Agents and the like.

<Example>
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by this Example. “Parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

  First, a method for measuring each physical property value and a method for evaluating the physical property will be described.

(1) Total light transmittance, haze value:
Measurement was performed using a haze meter HGM-2DP type manufactured by Suga Test Instruments Co., Ltd.

(2) Average refractive index of the composition:
The composition was sufficiently dried to remove the solvent and cured to produce a right-angle prism having two sides of 2 cm, an angle formed by the two sides of 90 °, and a thickness of 3 mm. Using this right angle prism, the average refractive index at a wavelength of 590 nm was measured with a refractometer KPR-200 manufactured by Kalnew Optical Co., Ltd. By observation with an electron microscope, it was confirmed that inorganic particles were arranged in a regular manner in this right-angle prism.

(3) Phase difference of transmitted light:
The phase difference value in the film thickness direction at a wavelength of 590 nm of transmitted light was measured using KOBRA-21ADH manufactured by Oji Scientific Instruments. Here, the retardation value in the film thickness direction is given by the following equation.

Thickness direction retardation value = (refractive index in film surface parallel direction−refractive index in film thickness direction) × film thickness (4) Thickness of retardation film:
A retardation film was formed on one side of unstrained glass (BK7) to prepare a measurement sample. The surface of the sample where the retardation film is not formed is painted with black spray, the reflection from the back surface is eliminated, and the reflectance is measured using a reflection spectral film thickness meter FTM-1000 manufactured by Otsuka Electronics Co., Ltd. The thickness of the retardation film was calculated.

(5) The difference between the refractive index in the direction parallel to the film surface of the retardation film and the refractive index in the film thickness direction:
For the obtained retardation film, an automatic birefringence meter KOBRA-21ADH manufactured by Oji Scientific Instruments Co., Ltd. and the average refractive index of the composition were used to determine the three-dimensional refractive indexes Nx, Ny, and Nz at a wavelength of 590 nm. The refractive index in the film surface parallel direction and the film thickness parallel direction of the obtained retardation film was calculated by the following equation.

Film surface parallel direction: (Nx + Ny) / 2
Film thickness direction: Nz
(6) Adhesiveness of retardation film:
In accordance with a cross cellophane tape peeling test described in JIS K5400, evaluation was made based on the remaining film rate (%) of 100 cross cells (1 mm square).

(7) Particle dispersibility in retardation film:
The cross section of the retardation film was observed with an electron microscope. A film in which no void was generated in the retardation film and no fine particles were aggregated was determined to be a retardation film having good particle dispersibility.

(8) Wet heat test:
The retardation element was held for 500 hours in an environment of a temperature of 40 ° C. and a relative humidity of 95%.

(9) Dry heat test:
The retardation element was held in an environment at a temperature of 80 ° C. for 500 hours.

<Production Example 1>
(Preparation of rutile needle-like titanium oxide particle dispersion (1))
Rutile needle-shaped titanium oxide fine powder (Ishihara Techno Co., Ltd., trade name: TTO-S-4, length of major axis (L _a ): 70 nm, ratio of major axis to minor axis length (L _a / D _b ) : 5) 3.5 parts by weight, Denkabutyral # 2000-L (manufactured by Denki Kagaku Kogyo Co., Ltd., polyvinyl butyral resin, average degree of polymerization: about 300, polyvinyl alcohol unit in one molecule: 21% by weight or more, glass transition Point (Tg): 71 ° C., PVB # 2000L (0.6 parts by weight), methyl isobutyl ketone (MIBK) (12 parts by weight), and t-butanol (8 parts by weight) were mixed and dispersed using glass beads for 10 hours. The glass beads were removed to obtain 24 parts by weight of a rutile needle-like titanium oxide particle dispersion (1). The obtained rutile-type acicular titanium oxide particle dispersion (1) was weighed on an aluminum dish and dried on a hot plate at 120 ° C. for 1 hour to determine the total solid content concentration. The total solid content was 17% by weight. Further, the rutile needle-like titanium oxide particle dispersion (1) was weighed in a magnetic crucible, preliminarily dried for 30 minutes on a hot plate at 80 ° C., and then fired in a muffle furnace at 750 ° C. for 1 hour. From the amount of inorganic residue and the total solid content, the inorganic content in the total solid content was determined to be 85% by weight.

<Production Example 2>
(Preparation of rutile needle-like titanium oxide particle dispersion (2))
Mixing 3.5 parts by weight of the rutile needle-like titanium oxide fine powder, 0.6 parts by weight of ethylene oxide-propylene oxide copolymer (average degree of polymerization: about 20), 12 parts by weight of MIBK, and 8 parts by weight of t-butanol After dispersing for 10 hours using glass beads, the glass beads were removed to obtain 24 parts by weight of a rutile needle-like titanium oxide particle dispersion (2). The total solid concentration of the rutile needle-like titanium oxide particle dispersion (2) and the inorganic content in the total solid were measured in the same manner as in Production Example 1. The total solid content was 17% by weight and the inorganic content was 85% by weight.

<Production Example 3>
(Preparation of zirconia-coated rutile needle-like titanium oxide particle dispersion)
Instead of rutile needle-like titanium oxide fine powder, rutile needle-like titanium oxide fine powder coated with zirconia (manufactured by Ishihara Techno Co., Ltd., trade name: TTO-S-2, length of major axis (L _a ): 70 nm
A zirconia-coated rutile needle-like titanium oxide particle dispersion was prepared in the same manner as in Production Example 2, except that the ratio of the length of the major axis to the minor axis (L _a / D _b ): 5) was used. The total solid concentration of the zirconia-coated rutile needle-like titanium oxide particle dispersion and the inorganic content in the total solid were measured in the same manner as in Production Example 1. The total solid content was 17% by weight and the inorganic content was 85% by weight.

<Production Example 4>
(Preparation of acicular tin oxide particle dispersion)
Instead of rutile acicular titanium oxide fine powder, acicular tin oxide fine powder (manufactured by Ishihara Techno Co., Ltd., trade name: FS-10P, length of major axis (L _a ): 1000 nm, major axis and minor axis length An acicular tin oxide particle dispersion was prepared in the same manner as in Production Example 2 except that the ratio (L _a / D _b ): 70) was used. The total solid content concentration of this acicular tin oxide particle dispersion and the inorganic content in the total solid content were measured in the same manner as in Production Example 1. The total solid content was 17% by weight and the inorganic content was 85% by weight.

<Comparative Production Example 1>
(Preparation of spherical titanium oxide particle dispersion)
Instead of rutile needle-like titanium oxide fine powder, spherical titanium oxide fine powder (manufactured by Ishihara Techno Co., Ltd., trade name: TTO-51 (D), length of major axis (L _a ): 40 nm, length of major axis and minor axis Ratio of (
A spherical titanium oxide particle dispersion was prepared in the same manner as in Production Example 2 except that L _a / D _b ): 1.2) was used. The total solid content concentration of this spherical titanium oxide particle dispersion and the inorganic content in the total solid content were measured in the same manner as in Production Example 1. The total solid content was 17% by weight and the inorganic content was 85% by weight.

<Comparative Production Example 2>
(Preparation of potassium titanate particle dispersion)
Instead of rutile acicular titanium oxide fine powder, potassium titanate fine powder (Otsuka Chemical Co., Ltd., trade name: TISMO N, major axis length (L _a): 15 [mu] m, the ratio of the length of the major axis to the minor axis ( L _a / D _b
): A potassium titanate particle dispersion was prepared in the same manner as in Production Example 2 except that 30) was used. The total solid content concentration and the inorganic content in the total solid content of this potassium titanate particle dispersion were measured in the same manner as in Production Example 1. The total solid content was 17% by weight and the inorganic content was 85% by weight.

  In a container, 100 parts by weight of the rutile needle-like titanium oxide particle dispersion (1) prepared in Production Example 1, 4 parts by weight of methoxylated methylmelamine (Cymel 303, Mitsui Cytec Co., Ltd.) as a binder, and start of curing 1 part by weight of catalyst 4050 (manufactured by Mitsui Cytec Co., Ltd., active ingredient concentration: 32% by weight) was added as an agent to obtain a uniform retardation film forming composition (1). The total solid concentration in the composition (1) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (1) was 5 mPa * s.

A uniform solution in the same manner as in Example 1 except that the rutile needle-like titanium oxide particle dispersion (2) prepared in Production Example 2 was used instead of the rutile needle-like titanium oxide particle dispersion (1). A retardation film forming composition (2) was obtained. The total solid content concentration in the composition (2) was measured in the same manner as in Production Example 1. The total solid content was 20% by weight. The viscosity (25 ° C.)
) Was 5 mPa · s.

  In place of the rutile needle-like titanium oxide particle dispersion (1), a uniform solution was prepared in the same manner as in Example 1 except that the zirconia-coated rutile needle-like titanium oxide particle dispersion prepared in Production Example 3 was used. A composition for forming a retardation film (3) was obtained. The total solid content concentration in the composition (3) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (3) was 5 mPa * s.

  Retardation film formation of a uniform solution in the same manner as in Example 1 except that the acicular tin oxide particle dispersion prepared in Production Example 4 was used instead of the rutile-type acicular titanium oxide particle dispersion (1). A composition (4) was obtained. The total solid content concentration in the composition (4) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (4) was 5 mPa * s.

  In a container, 100 parts by weight of the rutile needle-like titanium oxide particle dispersion (1) prepared in Production Example 1 and 4 parts by weight of Duranate MF-B60X (manufactured by Asahi Kasei Co., Ltd.) are added. A composition for forming a retardation film (5) was obtained. The total solid concentration in this composition (5) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (5) was 5 mPa * s.

  In the container, 100 parts by weight of the rutile needle-like titanium oxide particle dispersion (2) prepared in Production Example 2, 4 parts by weight of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.), and Irgacure 184 (Ciba) 1 part by weight of Specialty Chemicals Co., Ltd.) was added to obtain a uniform retardation film forming composition (6). The total solid concentration in this composition (6) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of the composition (6) was 5 mPa * s.

  In a container, 100 parts by weight of rutile needle-like titanium oxide particle dispersion (2) prepared in Production Example 2, 4 parts by weight of Adekaoptomer KRM-2110 (manufactured by Asahi Denka Kogyo Co., Ltd.), and Adekaoptomer SP-170 (manufactured by Asahi Denka Kogyo Co., Ltd.) was added in an amount of 1 part by weight to obtain a uniform retardation film forming composition (7). The total solid concentration in this composition (7) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (7) was 5 mPa * s.

  In the container, 100 parts by weight of the rutile needle-like titanium oxide particle dispersion (2) prepared in Production Example 2, 4 parts by weight of KC89 (manufactured by Shin-Etsu Silicone), Adekaoptomer SP-170 (Asahi Denka) 1 part by weight of Kogyo Co., Ltd. was added to obtain a uniform solution retardation film forming composition (8). The total solid concentration in this composition (8) was measured in the same manner as in Production Example 1. The total solid concentration was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (7) was 5 mPa * s.

<Comparative Example 1>
A uniform film-forming composition (as in Example 1) except that the spherical titanium oxide particle dispersion prepared in Comparative Production Example 1 was used instead of the rutile needle-like titanium oxide particle dispersion (1). a) was obtained. The total solid content concentration in the composition (a) was measured in the same manner as in Production Example 1. The total solid content was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (a) was 5 mPa * s.

<Comparative Example 2>
A uniform film-forming composition (as in Example 1) except that the potassium titanate particle dispersion prepared in Comparative Production Example 2 was used instead of the rutile needle-like titanium oxide particle dispersion (1). b) was obtained. The total solid content concentration in the composition (b) was measured in the same manner as in Production Example 1. The total solid content was 20% by weight. Moreover, the viscosity (25 degreeC) of this composition (b) was 10 mPa * s.

<Comparative Example 3>
Cymel 303 (Mitsui Cytec Co., Ltd.) 21 parts by weight, Catalyst 4050 (Mitsui Cytec Co., Ltd.) 1 part by weight, methyl isobutyl ketone 50 parts by weight and tert-butanol were added, and the phase difference of the uniform solution A film-forming composition (c) was obtained. The total solid concentration in the composition (c) was measured in the same manner as in Production Example 1. The total solid content was 20% by weight. Moreover, the viscosity (25 degreeC) of the composition (6) was 10 mPa * s.

  Tables 1 and 2 show the composition (parts by weight), total solid content concentration (% by weight), viscosity (mPa · s), and composition of the film-forming compositions prepared in Examples 1 to 8 and Comparative Examples 1 to 3. Indicates the average refractive index of the object.

Using the wire bar coater (# 12), the composition for forming a retardation film (1) prepared in Example 1 was cyclic olefin resin film (ARTON film manufactured by JSR Corporation, film thickness 100 μm, water absorption: 0.17%, photoelastic coefficient 3 × 10 ⁻¹³ cm ² / dyne), and unstrained glass (BK7: thickness 1 mm), respectively. In addition, a water absorption is the value calculated | required from the weight change at the time of being immersed in 23 degreeC water for 24 hours. This was dried at 120 ° C. for 60 minutes using an oven to obtain a retardation element (1) having a retardation film (1). The retardation value (nm), refractive index difference, film thickness (μm), and particle dispersibility in the retardation film of the retardation film (1) were evaluated. Further, the total light transmittance (%), haze (%), retardation value (nm), and adhesion of the retardation element (1) were evaluated. Table 3 shows the evaluation results for the retardation film (1) and the retardation element (1).

  The obtained retardation film (1) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (1), the adhesion between the retardation film (1) and the cyclic olefin-based resin film was good. In the retardation film (1) and the retardation element (1), no significant change from the initial characteristics was observed in the evaluation even after the wet heat test and the dry heat test.

  The retardation film (2) was prepared in the same manner as in Example 9, except that the retardation film forming composition (2) prepared in Example 2 was used instead of the retardation film forming composition (1). The phase difference element (2) which has was obtained. Evaluation similar to Example 9 was performed about this retardation film (2) and retardation element (2). Table 3 shows the evaluation results for the retardation film (2) and the retardation element (2).

  The obtained retardation film (2) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (2), the adhesion between the retardation film (2) and the cyclic olefin-based resin film was good. In the retardation film (2) and the retardation element (2), no significant change from the initial characteristics was observed in the evaluation even after the wet heat test and the dry heat test.

  The retardation film (3) was prepared in the same manner as in Example 9, except that the retardation film forming composition (3) prepared in Example 3 was used instead of the retardation film forming composition (1). The phase difference element (3) which has was obtained. Evaluation similar to Example 9 was performed about this retardation film (3) and retardation element (3). Table 3 shows the evaluation results of the retardation film (3) and the retardation element (3).

  The obtained retardation film (3) was excellent in transparency, and the retardation value in the film thickness direction was about 120 nm. In addition, in the retardation element (3), the adhesion between the retardation film (3) and the cyclic olefin-based resin film was good. In the retardation film (3) and the retardation element (3), no significant change from the initial characteristics was observed in the evaluation even after the wet heat test and the dry heat test.

  The retardation film (4) was prepared in the same manner as in Example 9, except that the retardation film forming composition (4) prepared in Example 4 was used instead of the retardation film forming composition (1). The phase difference element (4) which has was obtained. Evaluation similar to Example 9 was performed about this retardation film (4) and retardation element (4). Table 3 shows the evaluation results of the retardation film (4) and the retardation element (4).

  The obtained retardation film (4) was excellent in transparency, and the retardation value in the film thickness direction was about 80 nm. In addition, in the retardation element (4), the adhesion between the retardation film (4) and the cyclic olefin-based resin film was good. The retardation film (4) and the retardation element (4) showed no significant change from the initial characteristics in the evaluation even after the wet heat test and the dry heat test.

  The retardation film (5) was prepared in the same manner as in Example 9, except that the retardation film forming composition (5) prepared in Example 5 was used instead of the retardation film forming composition (1). The phase difference element (5) which has was obtained. Evaluation similar to Example 9 was performed about this retardation film (5) and retardation element (5). Table 3 shows the evaluation results of the retardation film (5) and the retardation element (5).

  The obtained retardation film (5) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (5), the adhesion between the retardation film (5) and the cyclic olefin-based resin film was good. The retardation film (5) and the retardation element (5) showed no significant change from the initial characteristics in the evaluation even after the wet heat test and the dry heat test.

The retardation film forming composition (6) prepared in Example 6 was applied to each of the cyclic olefin resin film and the unstrained glass (BK7: thickness 1 mm) using a wire bar coater (# 12). Worked. To this, using a metal halide lamp, 250 mW / cm ² , 1
Irradiation with J / cm ² ultraviolet rays gave a retardation element (6) having a retardation film (6). Evaluation similar to Example 9 was performed about this retardation film (6) and retardation element (6). Table 3 shows the evaluation results of the retardation film (6) and the retardation element (6).

  The obtained retardation film (6) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (6), the adhesion between the retardation film (6) and the cyclic olefin-based resin film was good. The retardation film (6) and the retardation element (6) showed no significant change from the initial characteristics in the evaluation even after the wet heat test and the dry heat test.

  In the same manner as in Example 14, except that the retardation film forming composition (7) prepared in Example 7 was used instead of the retardation film forming composition (6), the retardation film (7) and A phase difference element (7) was obtained. Evaluation similar to Example 9 was performed about this retardation film (7) and retardation element (7). Table 3 shows the evaluation results of the retardation film (7) and the retardation element (7).

  The obtained retardation film (7) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (7), the adhesion between the retardation film (7) and the cyclic olefin-based resin film was good. The retardation film (7) and the retardation element (7) showed no significant change from the initial characteristics in the evaluation even after the wet heat test and the dry heat test.

  In the same manner as in Example 14 except that the retardation film forming composition (8) prepared in Example 8 was used instead of the retardation film forming composition (6), the retardation film (8) and A phase difference element (8) was obtained. Evaluation similar to Example 9 was performed about this retardation film (8) and retardation element (8). Table 3 shows the evaluation results of the retardation film (8) and the retardation element (8).

  The obtained retardation film (8) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (8), the adhesion between the retardation film (8) and the cyclic olefin-based resin film was good. In the retardation film (8) and the retardation element (8), no significant change from the initial characteristics was observed in the evaluation even after the wet heat test and the dry heat test.

Example 14 except that a polycarbonate film (manufactured by Teijin Chemicals Ltd., water absorption: 0.2%, photoelastic coefficient 70 × 10 ⁻¹³ cm ² / dyne) was used instead of the cyclic olefin resin film. Similarly, a retardation film (9) and a retardation element (9) were obtained. Evaluation similar to Example 9 was performed about this retardation film (9) and retardation element (9). Table 3 shows the evaluation results of the retardation film (9) and the retardation element (9).

  The obtained retardation film (9) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. In addition, in the retardation element (9), the adhesion between the retardation film (9) and the cyclic olefin resin film was good.

  Although the performance of the retardation film (9) after the wet heat test and after the dry heat test hardly changed, the retardation value in the retardation element (9) decreased by about 10 nm from the initial evaluation result. Moreover, the adhesiveness after a wet heat test fell about 5%.

<Comparative example 4>
In the same manner as in Example 9, except that the film forming composition (a) prepared in Comparative Example 1 was used instead of the phase difference film forming composition (1), the phase having the phase difference film (a) was used. A phase difference element (a) was obtained. Evaluation similar to Example 9 was performed about this retardation film (a) and retardation element (a). Table 4 shows the evaluation results for the retardation film (a) and the retardation element (a). Although the obtained retardation film (a) had good transparency, a retardation value in the film thickness direction could not be obtained.

<Comparative Example 5>
In the same manner as in Example 9, except that the film forming composition (b) prepared in Comparative Example 2 was used instead of the phase difference film forming composition (1), the phase having the phase difference film (b) was used. A phase difference element (b) was obtained. Evaluation similar to Example 9 was performed about this retardation film (b) and retardation element (b). Table 4 shows the evaluation results for the retardation film (b) and the retardation element (b). The obtained retardation film (b) was not transparent, and the retardation value in the film thickness direction could not be measured.

<Comparative Example 6>
In the same manner as in Example 14, except that the film forming composition (c) prepared in Comparative Example 3 was used instead of the phase difference film forming composition (1), A phase difference element (c) was obtained. Evaluation similar to Example 9 was performed about this retardation film (c) and retardation element (c). Table 4 shows the evaluation results of the retardation film (c) and the retardation element (c). Although the obtained retardation film (c) had good transparency, a sufficient retardation value in the film thickness direction could not be obtained.

<Reference Production Example 1>
(Production of fluoropolymer)
A stainless steel autoclave with an electromagnetic stirrer with an internal volume of 1.5 L was sufficiently replaced with nitrogen gas, and then 500 g of ethyl acetate, 43.2 g of perfluoro (propyl vinyl ether) (FPVE), 41.2 g of ethyl vinyl ether (EVE), hydroxyethyl 21.5 g of vinyl ether (HEVE), 40.5 g of “ADEKA rear soap NE-30” (manufactured by Asahi Denka Kogyo Co., Ltd.) as a nonionic reactive emulsifier, and “VPS-1001” (Wako Jun) as an azo group-containing polydimethylsiloxane 6.0 g of Yakuhin Kogyo Co., Ltd. and 1.25 g of lauroyl peroxide were added and cooled to −50 ° C. with dry ice-methanol, and then oxygen in the system was removed again with nitrogen gas.

Next, 97.4 g of hexafluoropropylene (HFP) was added, and the temperature increase was started. The pressure when the temperature in the autoclave reached 60 ° C. was 5.3 × 10 ⁵ Pa. Thereafter, the reaction was continued with stirring at 70 ° C. for 20 hours. When the pressure dropped to 1.7 × 10 ⁵ Pa, the autoclave was cooled with water to stop the reaction. After reaching room temperature, unreacted monomers were released and the autoclave was opened to obtain a polymer solution having a solid content concentration of 26.4%. The obtained polymer solution was put into methanol to precipitate a polymer, washed with methanol, and vacuum dried at 50 ° C. to obtain 220 g of a fluoropolymer.

  The obtained polymer has a polystyrene-equivalent number average molecular weight (Mn) of 48,000 by gel permeation chromatography (GPC), a glass transition temperature (Tg) of 26.8 ° C. by DSC, and a fluorine content by the alizarin complexone method. It was 50.3%.

<Reference Production Example 2>
(Preparation of composition for forming antireflection film)
100 g of the fluoropolymer obtained in Reference Production Example 1 was dissolved in 900 g of MIBK together with 30 g of Cymel 303 (Mitsui Cytec Co., Ltd.), and reacted at 100 ° C. for 5 hours with stirring. By adding 100 g of the obtained reaction liquid and 2 g of catalyst 4050 (manufactured by Mitsui Cytec Co., Ltd., aromatic sulfonic acid compound, solid concentration 32 wt%) as a curing catalyst to 900 g of MIBK, An antireflection film-forming composition was prepared. The MIBK solution of this composition was applied onto a silicon wafer by a spin coater so that the thickness after drying was about 0.1 μm. This was heated at 120 ° C. for 60 minutes using an oven to obtain an antireflection film. With respect to the obtained antireflection film, the refractive index (n _D ²⁵ ) at a wavelength of 589 nm at 25 ° C. was measured using an ellipsometer, and it was 1.41.

  On the retardation film (6) obtained in Example 14, the antireflection film-forming composition prepared in Reference Production Example 2 was further coated using a wire bar coater (# 3). This was dried at 120 ° C. for 60 minutes using an oven to obtain a retardation film (10) having an antireflection film as an upper layer. When the film thickness of this antireflection film was calculated by reflectance measurement, it was about 0.1 μm. Evaluation similar to Example 9 was performed about this retardation film (10) and retardation element (10). Table 3 shows the evaluation results of the retardation film (10) and the retardation element (10).

  The obtained retardation film (10) was excellent in transparency, and the retardation value in the film thickness direction was about 150 nm. Further, the transmittance was improved to 90% or more. In addition, in the retardation element (10), the adhesion between the retardation film (10) and the cyclic olefin-based resin film was good. The retardation film (10) and the retardation element (10) showed no significant change from the initial characteristics in the evaluation even after the wet heat test and the dry heat test.

(Preparation of a polarizing plate using a retardation film composed of a retardation film and a transparent film as a protective film)
A polyvinyl alcohol film having a thickness of 50 μm was uniaxially stretched up to 4 times in about 5 minutes while being immersed in a 40 ° C. bath composed of 5 g of iodine, 250 g of potassium iodide, 10 g of boric acid, and 1000 g of water to obtain a polarizing film. On the surface of this polarizing film, 100 parts of an acrylic resin comprising 90% by weight of n-butyl acrylate, 7% by weight of ethyl acrylate and 3% by weight of acrylic acid and trimethylolpropane (1 mole) of tolylene diisocyanate (3 moles). Using the pressure-sensitive adhesive obtained by mixing 2 parts of a 75% by weight ethyl acetate solution of the adduct, the retardation element (1) prepared in Example 9, and a triacetyl cellulose film (thickness) 80 μm: manufactured by Fuji Photo Film Co., Ltd.) was adhered to one side of the polarizing film to obtain a polarizing plate (1). This polarizing plate (1) was subjected to a durability test for 500 hours under the conditions of 80 ° C. and 90% relative humidity, and when the appearance change was visually observed, no abnormality in the appearance such as whitening or swelling was observed. Further, the degree of polarization was also confirmed to have a good degree of durability since the degree of polarization was maintained at 95% or more with respect to the initial value.

(Preparation of a polarizing plate using a retardation film composed of a retardation film and a retardation film as a protective film)
A retardation element (11) was produced in the same manner as in Example 9 using a cyclic olefin resin film (ARTON film manufactured by JSR Corporation) whose in-plane retardation value was adjusted to 100 nm by uniaxial stretching in advance. A polarizing plate (2) was obtained in the same manner as in Example 19 except that this retardation element (11) was used instead of the retardation element (1). When this polarizing plate (2) was subjected to a durability test for 500 hours under the conditions of 80 ° C. and 90% relative humidity, and the appearance change was visually observed, none of the appearance abnormalities such as whitening or blistering were observed. Further, the degree of polarization was also confirmed to have a good degree of durability since the degree of polarization was maintained at 95% or more with respect to the initial value.

(Preparation of a polarizing plate having a transparent conductive film)
With respect to the retardation element (1) obtained in Example 9, the surface opposite to the surface on which the retardation film is provided, using a sputtering machine (manufactured by Chugai Kogyo Kogyo Co., Ltd.), transparent conductivity under the following conditions A film (ITO film) was formed to obtain a retardation element (12) having a transparent conductive film.

Power supply: High frequency power supply of MHz Substrate temperature: 70 ° C
Target: Alloy of In ₂ O ₃ / SnO ₂ = 90/10 (weight ratio) Atmosphere: Under argon gas inflow Sputter speed: 270 Å / min Sputter pressure: 10 ⁻² Torr
The obtained ITO film had a thickness of 2,500 Å and a specific resistance of 1.5 × 10 ⁻³ Ω · cm. When the adhesion of the ITO film was evaluated in the same manner as in Example 9, the residual film ratio was 100%. A polarizing plate (3) was obtained in the same manner as in Example 19 except that this retardation element (12) was used instead of the retardation element (1). When this polarizing plate (3) was subjected to an endurance test for 500 hours under the conditions of 80 ° C. and 90% relative humidity, and visually observed for changes in its appearance, none of the appearance abnormalities such as whitening or swelling were observed. Further, the degree of polarization was also confirmed to have a good degree of durability since the degree of polarization was maintained at 95% or more with respect to the initial value.

(Preparation of a polarizing plate having a transparent conductive film)
A phase difference element (13) was obtained in the same manner as in Example 21 except that the phase difference element (11) obtained in Example 20 was used instead of the phase difference element (1).

The obtained ITO film had a thickness of 2,500 Å and a specific resistance of 1.5 × 10 ⁻³ Ω · cm. When the adhesion of the ITO film was evaluated in the same manner as in Example 9, the residual film ratio was 100%. A polarizing plate (4) was obtained in the same manner as in Example 19 except that this retardation element (13) was used instead of the retardation element (1). This polarizing plate (4) was subjected to a durability test for 500 hours under the conditions of 80 ° C. and 90% relative humidity, and when the appearance change was visually observed, no appearance abnormality such as whitening or blistering was observed. Further, the degree of polarization was also confirmed to have a good degree of durability since the degree of polarization was maintained at 95% or more with respect to the initial value.

The retardation film, retardation element, and polarizing plate according to the present invention have excellent birefringence and transparency, and can obtain a stable viewing angle over a long period of time. Can be used. For example, mobile phones, digital information terminals, pagers, navigation, in-vehicle liquid crystal displays, liquid crystal monitors, dimming panels, OA equipment displays, AV equipment displays and other liquid crystal display elements, electroluminescence display elements, touch panels, etc. Can be used. CD, CD-R, MD, MO,
It is also useful as a wave plate used in an optical disk recording / reproducing apparatus such as a DVD.

Claims (7)

(A) needle-like inorganic particles exhibiting shape anisotropy having a major axis and a minor axis, and having a birefringence greater than the average refractive index in the direction perpendicular to the major axis direction in the major axis direction;
(B) A retardation film-forming composition containing a binder that is a curable compound for immobilizing the acicular inorganic particles (A),
A difference in refractive index between the film surface parallel direction and the film thickness direction is caused in the unstretched retardation film formed from the composition, and the refractive index in the film surface parallel direction is higher than the refractive index in the film thickness direction. A composition for forming a retardation film, which is large. In the retardation film formed from the retardation film forming composition, the major axis direction of the needle-like inorganic particles (A) is arranged substantially parallel to the film plane,
Due to the difference between the refractive index in the major axis direction of the needle-like inorganic particles (A) and the refractive index in the direction perpendicular to the major axis direction, the retardation film has a difference in refractive index between the film surface parallel direction and the film thickness direction. The composition for forming a retardation film according to claim 1, wherein the composition is formed.   3. The composition for forming a retardation film according to claim 1, wherein a difference between a refractive index in the film surface parallel direction and a refractive index in the film thickness direction of the retardation film is 0.010 or more.   The composition for forming a retardation film according to any one of claims 1 to 3, wherein the acicular inorganic particles (A) are acicular inorganic particles having crystallinity having an average major axis of 2 µm or less. object.   The curable compound is (i) a melamine compound, (ii) an isocyanate compound, (iii) an acrylate compound, (iv) an epoxy compound, or (v) a hydrolyzable silane compound. 5. The composition for forming a retardation film according to any one of 4 above.   The retardation film according to any one of claims 1 to 5, wherein the amount of the binder (B) added is 1 to 200 parts by weight with respect to 100 parts by weight of the needle-like inorganic particles (A). Forming composition.   The composition for forming a retardation film according to claim 1, further comprising a curing initiator (C).