JP2006028204A - Composition for anisotropic light-scattering film and anisotropic light-scattering film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anisotropic light-scattering film which has anisotropicity (forward or backward, and dependency of incidence angle) on scattering characteristics, can also easily control the scattering characteristics related to longitudinal and lateral scattering ranges, and does not change the color of display light dependent on an observation position, and to provide a composition for the film. <P>SOLUTION: This composition for the anisotropic light-scattering films is characterized by comprising at least (A) a thermoplastic resin, (B) a compound having at least one cation-polymerizable group in the molecule, and (C) a photopolymerization initiator which produces a radical species by chemical radiations, and having a difference between the refractive index of (A) the thermoplastic resin and the refractive index of (B) the compound having at least one cation-polymerizable group in the molecule. Portions having different refractive indexes are distributed in irregular shapes / thicknesses, and light and shade patterns comprising the unevenness of the refractive indexes are thereby formed. The anisotropic light-scattering film has a structure in which portions having different refractive indexes are distributed in a layer state inclined to the thickness direction of the film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composition for a light-scattering film and an anisotropic light-scattering film that have different scattering properties (or have an incident-angle selectivity) depending on the incident angle of light and have anisotropy in light scattering properties.

  In a display device using light such as a reflective liquid crystal display device or a transmissive liquid crystal display device, a viewing angle at the time of observation is ensured (that is, the display image is brightly displayed on the front surface of the display device), In order to make the display screen visible with uniform brightness over the entire surface of the display screen, a light diffusion film is disposed on the front surface of the apparatus. As a conventional light scattering film, a resin film whose surface is processed into a mat shape, a resin film including a diffusing material inside, or the like is used.

  In the case of a conventional resin film processed into a mat shape or a film containing a diffusing material inside, it is difficult in principle to have a function such as a change in scattering depending on the incident angle of incident light. There is no such function.

  In the case of a light-scattering film whose surface has been processed into a mat shape, the mat surface is physically formed on the film surface like a sand blaster treatment, or the mat surface is chemically formed by dissolution treatment with an acidic or alkaline solution. . Accordingly, it is difficult to control the light scattering property, and it is impossible to change the vertical and horizontal scattering properties, so that it is impossible to provide scattering anisotropy.

  In addition, even in a light scattering film including a diffusing material inside, an attempt has been made to control the refractive index, size, shape, etc. of the diffusing material in order to control the scattering property, but this is technically difficult. It is expensive and not practical enough.

  Therefore, in the above light scattering film, there is no scattering incident angle dependency and there is little or no light scattering anisotropy, so unnecessary scattered light is generated when used in a display device, and as a result. There is a problem that the brightness of the display and the contrast are lowered or the display image is blurred.

  On the other hand, Patent Document 1 is known as a proposal relating to a reflective liquid crystal display device using a scattering plate having anisotropy in light scattering. The scattering plate disclosed in the above publication is a scattering plate having little back scattering characteristics and strong forward scattering characteristics, and selectively scatters either incident light to the liquid crystal display device or outgoing display light from the liquid crystal display device. It has the characteristic to make it.

  However, in the above publication, the configuration of the scattering plate is not specifically described, but only describes “transparent fine particles solidified with a transparent polymerizable polymer”. In such a scattering plate, even if the scattering characteristic is given anisotropy (forward or backward), as in the case of the above-mentioned “light diffusing film including a diffusing material inside”, the vertical and horizontal scattering can be achieved. It is difficult to control even the characteristics.

Patent Document 2 is known as a proposal relating to a transmission type liquid crystal display device using a hologram as a scattering plate. The above proposal scatters display light emitted from a liquid crystal display device having a backlight, and employs a hologram as a scattering plate. Therefore, it is easy to make the scattering characteristics anisotropic, Although it is also possible to control the lateral scattering characteristics, it will inevitably involve spectroscopy (wavelength dispersion), so the color of the display light will change as the viewing point changes. Will be.
JP-A-8-20180 Japanese Patent Laid-Open No. 9-152602

  The present invention gives the scattering characteristics anisotropy (forward or backward, and dependency on the incident angle), makes it easy to control the scattering characteristics related to the vertical and horizontal scattering ranges, and displays them depending on the observation position. An object is to provide a composition and an anisotropic light scattering film for obtaining an anisotropic scatterer in which the color of light does not change.

  In the anisotropic scattering film obtained from the present invention, a portion having different refractive indexes is distributed in an irregular shape / thickness inside the film, so that a light and shade pattern having a refractive index is formed. By optimizing the size, shape, and distribution of different parts of the film along the longitudinal and lateral directions on the film surface and the thickness direction of the film, the scattering characteristics depending on the incident angle can be changed and unnecessary. The present invention is characterized in that light is scattered only in a necessary direction (range) without scattering light in the direction, and the present invention has a difference in refractive index between the thermoplastic resin and the cationic polymerizable compound. An anisotropic scattering film composition is provided.

  The invention according to claim 1 comprises at least a thermoplastic resin (A), a compound (B) having a cationic polymerizable group, and a photopolymerization initiator (C) that generates cationic species by actinic radiation, An anisotropic light-scattering film composition characterized in that there is a difference between the refractive index of the thermoplastic resin (A) and the refractive index of the cationically polymerizable compound (B).

  The invention according to claim 2 is the composition for anisotropic light scattering film according to claim 1, wherein the thermoplastic resin (A) is composed of either a bisphenol A type phenoxy resin or a bisphenol F type phenoxy resin. It is a thing.

  In the invention according to claim 3, the compound (B) having the cationic polymerizable group is composed of at least one compound selected from a compound having an oxirane ring, a compound having an oxetane ring, or a vinyl ether compound. The composition for anisotropic light-scattering films according to claim 1, wherein the composition is an anisotropic light-scattering film.

  The invention according to claim 4 is characterized in that the compound (B) having the cationic polymerizable group is blended in the range of 10 to 300 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A). Item 4. The composition for anisotropic light scattering film according to any one of Items 1 to 3.

  The invention according to claim 5 is the composition for anisotropic light scattering film according to claim 2, wherein the thermoplastic resin (A) has a weight average molecular weight in the range of 10,000 to 100,000. It is.

  Invention of Claim 6 provides the resin layer which consists of a composition for anisotropic light-scattering films in any one of Claim 1 to 5 in a base material, and exposes this resin layer, The inside of a resin layer, The anisotropic light-scattering film is characterized in that a portion having a different refractive index is distributed with an irregular shape and thickness, thereby forming a shaded portion having a high and low refractive index.

  The invention according to claim 7 is the anisotropic light according to claim 6, characterized in that the portions having different refractive indexes are distributed in a layered manner inclined with respect to the thickness direction of the resin layer. It is a scattering film.

  The invention according to claim 8 is the anisotropic light scattering film according to claim 6 or 7, wherein the substrate is a plastic film.

If this composition is used, light scattering occurs for light incident at a predetermined angle, and conversely, it functions as a transparent film for light perpendicular thereto, thereby providing light scattering with incident angle selectivity. Therefore, light that requires scattering and light that does not require scattering can be separated by the incident angle on the film, and as a result, when used in a display device, etc., display is performed without unnecessary scattering. It is possible to produce a light scattering film having effects such as improving the brightness, fineness, and contrast of the display and reducing blurring of the display image.

  In addition, when light is incident at an incident angle at which light scattering occurs, it is possible to produce a film having a scattering anisotropy in which the spread of the scattered light differs vertically and horizontally. Therefore, it is possible to emit scattered light only in a necessary direction. As a result, when used in a display device or the like, there is an effect of improving display brightness and contrast without causing unnecessary scattering.

  The present invention will be described below with reference to the drawings. FIG. 1 shows a light scattering film 1 in which portions having different refractive indexes are distributed in an irregular shape and thickness, and a light and shade pattern having a high and low refractive index (expressed in white and black in the figure) is formed. Are left side plan views and right side sectional views.

  As can be seen from the plan view, the shape of the portion having a different refractive index is horizontally long. Further, as can be seen from the cross-sectional view, the portions having different refractive indexes have a structure distributed in a layer shape inclined with respect to the thickness direction of the film. In FIG. 1, the refractive index distribution is uniform (the color does not change in the inclined direction) in the direction in which the portions having different refractive indexes are inclined in layers.

  Drawing 2 is an explanatory view showing light scattering film 1 concerning another embodiment, and the left is a top view and the right is a sectional view. In FIG. 2, the shape of the part with different refractive index is vertically long, and the refractive index distribution is irregular in the direction in which the part with different refractive index is inclined in layers (the color changes even in the inclined direction). Is).

  First, the optical characteristics of the light scattering film of FIGS. Light scattering occurs with respect to light incident at an angle along the tilt direction in which portions having different refractive indexes are distributed in layers (in the direction of arrow 2 in FIG. 2, which forms an angle θ from the normal of the film). Become.

  For light incident at an angle perpendicular to the tilt direction (the direction of arrow 3 in the figure), it functions as a simple transparent film, and the incident light is emitted without being scattered.

  Next, considering the plan view, if the shape of the part with different refractive index is vertically long (or horizontally long) and light incident on that part is scattered and emitted, the light scattering characteristics of the emitted light from each part However, it has anisotropy that is horizontally long (or vertically long). In FIG. 1, since the shape is horizontally long, the emitted light is scattered vertically. In FIG. 2, since the shape is vertically long, the emitted light is scattered horizontally.

  FIG. 3 is a graph showing an example of the incident angle dependency of the light scattering film 1 produced using the composition of the present invention. As indicated by the solid line in the figure, the haze value is 80% or more for light in a specific incident angle range (0 to 60 degrees in the figure), and conversely, the incident angle (-60 degrees in the figure) is symmetric. The haze value with respect to light of 0 degree to 20 degrees or less is 20% or less, which indicates the incident angle dependency of the scattering property referred to in this specification.

  In addition, as described above, when the shape of the part having different refractive index is vertically long (or horizontally long), when light incident on the part is scattered and emitted, the light scattering characteristics of the light emitted from each part are , Has anisotropy that is horizontally long (or vertically long) For example, if the shape is horizontally long as shown in FIG. 1, the scattered outgoing light from the light scattering film has a distribution that becomes a vertically long ellipse as shown in FIG.

  Next, the composition for anisotropic light scattering film of the present invention will be described in detail. As described above, the inside of the anisotropic light-scattering film produced with the composition of the present invention has a light and shade pattern with a high and low refractive index formed by irregularly distributed portions having different refractive indexes. Has been.

  If the difference in refractive index is too small, the scattering property is deteriorated. On the other hand, if the difference is too large, light scattering occurs regardless of the angle at which light is incident. It becomes difficult to have.

  The composition for anisotropic light scattering film of the present invention is a thermoplastic resin (A), a compound (B) having a cationic polymerizable group, and has a refractive index difference of 0.01 or more from the thermoplastic resin (A). A compound characterized by the above.

  The thermoplastic resin (A) is a resin that softens without being reacted by heating and exhibits plasticity, and that plasticity is reversibly maintained when cooling and heating are repeated. Thermoplastic resins are highly flexible, so that it is easy to move the compound having a cationic polymerizable group in an anisotropic light-scattering film, and the difference in refractive index is increased, so that the scattering property is improved. To do. Furthermore, since the produced light anisotropic scattering film also has flexibility, it can be easily used as an optical film.

  Examples of the thermoplastic resin (A) include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate or copolymers of various acrylates and methacrylates, and polyamide, polyester, polyvinyl acetate, polycarbonate, phenylene oxide, and polyacetal. There can be mentioned.

  Among these, preferable thermoplastic resin (A) includes bisphenol A type or bisphenol F type phenoxy resin. Phenoxy resin is tough and excellent in flexibility, and also has good properties as an anisotropic light scattering film because it has good adhesion to substrates such as PET (polyethylene terephthalate) and TAC (triacetate cellulose) films and fillers. Have.

  Furthermore, the preferred weight average molecular weight of the bisphenol A type or bisphenol F type phenoxy resin as the thermoplastic resin (A) is preferably 10,000 to 100,000. Bisphenol type resins having a molecular weight smaller than this average molecular weight are classified as epoxy resins, and are thermosetting resins. On the other hand, a bisphenol resin having a large average molecular weight has poor solubility in an organic solvent, making it difficult to use it as an anisotropic light scattering film.

  The refractive index of the thermoplastic resin (A) used in the present invention and the compound (B) having a cationic polymerizable group must be different. The greater the difference in refractive index, the more light is scattered, so-called Increases the haze rate. In general, the difference in refractive index is preferably 0.01 or more, more preferably 0.05 or more.

  The compound (B) having at least one cationic polymerizable group in the molecule used in the composition of the present invention needs to have a refractive index lower than that of the (A) thermoplastic resin, and is also liquid during heating after exposure. Such a thing is desirable. Furthermore, since it exists as a polymer in the produced anisotropic scattering film, there is no adverse effect such as thermal deterioration, and the properties of the cured product can be improved by combining appropriate compounds.

  Preferred examples of the compound having an oxirane ring include aliphatic polyhydric alcohols or (poly) glycidyl ethers of alkylene oxide adducts thereof. Typical examples include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, (di, tri, poly) ethylene. Examples include diglycidyl ether of glycol, diglycidyl ether of (di, tri, poly) propylene glycol, and the like.

  Other compounds having an oxirane ring include 1,2,5,6-diepoxy-4,7-methanoperhydroindene, 2- (3,4-epoxycyclohexyl) -3 ′, 4′-epoxy-1, 3-dioxane-5-spirocyclohexane, 1,2-ethylenedioxy-bis (3,4-epoxycyclohexylmethane), 4 ', 5'-epoxy-2'-methylcyclohexylmethyl-4,5-epoxy-2 -Methylcyclohexylcarboxylate, ethylene glycol-bis (3,4-epoxycyclohexylcarboxylate), bis- (3,4-epoxycyclohexylmethyl) adipate, 1,2,7,8-diepoxyoctane or 3, 4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylcarboxylate Alicyclic epoxy compound having an epoxy group or an epoxycyclohexyl group such as and the like.

  Preferred compounds having an oxetane ring are trimethylene oxide, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and 3-ethyl-3- (phenoxymethyl) oxetane. , 3-ethyl-3- (p-tolylmethyl) oxetane, 3-ethyl-3- (naphthoxymethyl) oxetane, 3,3′-bis (phenoxymethyl) oxetane, 1,4-bis {[(3-ethyl -3-oxetanyl) methoxy] methyl} benzene and the like.

Preferred examples of the vinyl ether compound include vinyl-2-chloroethyl ether, vinyl-n-propyl ether, vinyl-n-butyl ether, vinyl isoamyl ether, vinyl-n-octadecyl ether, triethylene glycol divinyl ether, 1,4-cyclohexane. Vinyl ethers such as methanol divinyl ether, trimethylol methane trivinyl ether, phenyl vinyl ether, p-tolyl vinyl ether, p-methoxyphenyl vinyl ether, naphthyl vinyl ether, bis (4-vinyloxymethylcyclohexylmethyl) glutarate, bis (4-vinyloxybutyl) isophthalate Compounds, but not limited to these. Moreover, the refractive index of these compounds needs to be lower than (A) thermoplastic resin.
In addition to these monofunctional cation monomers, a polyfunctional cation monomer may be included, or a mixture thereof may be used, and (A) the difference in refractive index from the thermoplastic resin is 0.01 or more. It is necessary to select a monomer. In addition, these compounds can be used as monomers or as oligomers or reactive polymers.

Examples of the photopolymerization initiator (C) that generates cationic species by actinic radiation used in the composition of the present invention include J. Org. Photochem. Sci. Technol. , 2, 283 (1987). And specifically, iron arene complexes, trihalogenomethyl-substituted s-triazines, sulfonium salts, diazonium salts, phosphonium salts, selenonium salts, arsonium salts, iodonium salts, and the like. Moreover, as an iodonium salt, Macromolecules, 10, 1307 (1977). Compounds such as diphenyliodonium, ditolyliodonium, phenyl (p-anisyl) iodonium, bis (m-nitrophenyl) iodonium, bis (p-tert-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium, etc. Iodonium chloride, bromide or sulfonium organoboron complexes such as borofluoride, hexafluorophosphate salt, hexafluoroarsenate salt, aromatic sulfonate, and diphenylphenacylsulfonium (n-butyl) triphenylborate You can list things.
(C) The photoinitiator that generates a cationic species by actinic radiation according to the present invention (D) The sensitizing dye includes cyanine or merocyanine derivatives, coumarin derivatives, chalcone derivatives, xanthene derivatives, thioxanthene derivatives, and azurenium derivatives. Organic dye compounds such as squarylium derivatives and porphyrin derivatives can be used, and in addition, “Dye Handbook” (Shin Okawara et al., Kodansha 1986), “Chemicals of Functional Dye” (Shin Okawara et al., CM 1981), The dyes and sensitizers described in “Special Functional Materials” (Chemical Icmori, et al., CMC 1986) are used. In addition, it is not limited to these, If it is a pigment | dye and sensitizer which show absorption with respect to the light of other visible region, it can be used. Two or more of these may be used in any ratio as required.
The amount of the compound (B) having at least one cationic polymerizable group in the molecule contained in the composition of the present invention is 10 to 300 parts by weight, preferably 20 parts per 100 parts by weight of the (A) thermoplastic resin. To 200 parts by weight. The amount of the photopolymerization initiator (C) that generates cationic species by actinic radiation is 0.1 to 50 parts by weight with respect to 100 parts by weight of the compound (B) having at least one cationic polymerizable group in the molecule. The amount is preferably 1 to 30 parts by weight. Further, the amount of the (D) sensitizing dye is 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the compound (B) having at least one cationic polymerizable group in the molecule. It is possible to take a range up to a part. The amount used is limited by the film thickness of the photosensitive layer and the optical density of the film thickness. That is, it is preferable to use the optical density within a range not exceeding 2.
Each of these components is appropriately selected, and the photosensitive solution obtained by mixing at an arbitrary ratio is a glass plate using a known coating means such as a bar coater, applicator, doctor blade, roll coater, die coater, comma coater, It is applied to a substrate such as a PET film or a TAC film.
In addition, when apply | coating a photosensitive solution, you may dilute with a suitable solvent as needed, but in that case, after apply | coating on a base material, drying is required. Examples of the solvent include dichloromethane, chloroform, acetone, 2-butanone, cyclohexanone, ethyl acetate, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-methoxy. Ethyl ether, 2-ethoxyethyl ether, 2- (2-ethoxyethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate , Tetrahydrofuran, 1,4-dioxane and the like.
Furthermore, since the recordable refractive index difference is limited by the manufacturing method and recording material, the film thickness is reduced when there is a large refractive index difference, and the film thickness is increased when there is a small refractive index difference. Thus, it is possible to realize an anisotropic light scattering film using the composition of the present invention.

  The sizes of the portions having different refractive indexes are random and non-regular in order to cause light scattering, but in order to have the necessary scattering properties, the average size is within a range of 0.1 μm to 300 μm in diameter. It selects suitably according to the scattering property required for each use.

Further, the distribution of the portions having different refractive indexes on the film surface is random and non-regular in order to cause light scattering. When>, the probability distribution exhibits a normal distribution centered on <n>. Alternatively, it may be distributed according to a probability distribution in which the minimum value n _min of the refractive index n decreases exponentially and the maximum value n _max of the refractive index decreases, or a probability distribution that increases monotonically.

  The means for producing the anisotropic light scattering film of the present invention will be described below. The light scattering film of the present invention can be produced by optical exposure means. FIG. 5 is an explanatory diagram showing an example of an optical system manufactured using a random mask pattern. The ultraviolet light emitted from the UV light source 6 is converted into parallel light 8 by the collimating optical system 7 and irradiated on the mask original plate 9.

  The photosensitive material 5 is disposed in close contact with the surface of the mask original 9 opposite to the UV irradiation side, and the pattern of the mask original 9 is exposed to the photosensitive material 5 by exposure. At this time, the UV parallel light 8 and the mask original plate 9 are inclined at a predetermined angle α as shown in the figure, so that pattern exposure is performed at a predetermined angle in the photosensitive material 5. Since this angle corresponds to the inclination angle of the portion having a different refractive index in the anisotropic light-scattering film (that is, the incident angle-dependent scattering angle θ), the angle is 0 to 60 degrees depending on the application. It selects suitably within the range of a grade.

  The mask original plate 9 having a predetermined random pattern used in FIG. 5 is obtained by etching the black and white pattern data prepared from the random number calculation using a computer as the metal chromium pattern 11 on the glass substrate 10 by the photolithography technique. It may be used. Of course, the method for preparing the mask original plate is not limited to the above-described method, and it is well known that a similar mask can be manufactured even if it is manufactured by a photographic technique using a squirrel plate.

  FIG. 6 is an explanatory view showing an example of an optical system for producing the anisotropic light scattering film having the structure shown in FIG. 2 using a speckle pattern. A glass 15 is irradiated with a laser beam 14 emitted from a laser light source 13. The photosensitive material 5 is disposed at a predetermined distance F on the surface opposite to the laser irradiation side of the frosted glass 15, and a speckle pattern, which is a complicated interference pattern generated by the laser light transmitted and scattered by the frosted glass 15, is formed on the photosensitive material 5. Exposure exposure.

  At this time, since the ground glass 10 and the photosensitive material 5 are inclined at a predetermined angle α as shown in the figure, the speckle pattern is exposed in the photosensitive material at a predetermined angle. Since this angle corresponds to the inclination of the portion having a different refractive index in the anisotropic light-scattering film (that is, the incident angle-dependent scattering peak angle θ), the angle is 0 to 60 degrees depending on the application. It selects suitably within the range of a grade.

  The laser light source used for recording can be appropriately selected from the 514.5 nm, 488 nm, 57.9 nm, 363.5 nm, and 357.1 nm wavelengths of an argon ion laser according to the sensitivity of the photosensitive material. . Other than the argon ion laser, any laser light source having good coherency can be used. For example, a semiconductor laser capable of oscillating at 532 nm and 355 nm, such as a helium neon laser and a krypton ion laser, can be used.

  The speckle pattern is a bright and dark speckle pattern that occurs when light with good coherence is scattered or reflected or transmitted by a rough surface, and is generated because light scattered by minute irregularities on the rough surface interferes with an irregular phase relationship. Is.

  According to the description (p.266-p.268) of “Light Measurement Handbook” (Asakura Shoten, Toshiharu Tamitsu et al., Published on November 25, 1994), specifications that show random values depending on the position of concentration and phase. In the pattern, the average size of the pattern is determined in inverse proportion to the angle at which the diffusion plate is viewed from the photosensitive material. Therefore, when the size of the diffusion plate is made larger in the vertical direction than in the horizontal direction, the pattern recorded on the photosensitive material is finer in the vertical direction than in the horizontal direction.

The speckle pattern by the manufacturing method in the optical system of FIG. 6 has a wavelength λ of the laser beam to be used, a size D of the ground glass, and a distance F between the ground glass and the photosensitive material, and the average size d of the speckle pattern to be recorded. Generally, it is expressed by the following formula.
d = 1.2λF / D
The average length t in the depth direction of the speckle pattern is t = 4.0λ (F / D) ²
It is represented by

  As described above, an anisotropic light scattering film having a desired three-dimensional refractive index distribution can be obtained by optimizing the values of λ and F / D so as to have an optimum scattering property.

  As an example, when λ = 0.5 μm and F / D = 2, d = 1.2 μm and t = 8 μm, and the shading pattern on the film surface is distributed with an average of 1.2 μm, and in the film thickness direction, It is distributed with an average size of 8 μm in the direction according to the inclination angle.

  However, these sizes are only average sizes, and in fact, the portions with different refractive indexes of various sizes, mainly these sizes, are distributed on the surface and in the depth direction. Thus, the anisotropic light scattering film of the present invention as shown in FIG. 2 is obtained.

  In addition, when it is set as the film which provided the anisotropic scattering film integrally with base materials, such as the above-mentioned plastic film, it is necessary to set it as the composition which was excellent in adhesiveness with a base material, and also separates adhesives etc. It is necessary to have excellent adhesion even after exposure without using a member.

The above-mentioned problem is solved by a thermoplastic resin (A) comprising either a bisphenol A type phenoxy resin or a bisphenol F type phenoxy resin, a compound (B) having at least one cation polymerizable group in the molecule, and a cationic species by actinic radiation. This can be solved by using an anisotropic light-scattering film composition containing a photopolymerization initiator (C) that generates water.
Hereinafter, embodiments of the present invention will be described with reference to specific examples and comparative examples for clarifying the features of the present invention.

<Example 1>
100 parts by weight of phenoxy resin (trade name biscoat 1256, weight average molecular weight 51,000, manufactured by Japan Epoxy Resin Co., Ltd.), 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexylcarboxylate (Nippon Specialty Chemicals ( Product name Araldite CY179) 100 parts by weight and (4-methylphenyl) [4- (2-methylpropyl) phenyl] iodonium hexafluorophosphate (Ciba Specialty Chemicals, Inc., trade name IRGACURE250) 5.0 A photosensitive solution was prepared by mixing and dissolving 0.25 parts by weight of 4,4′-bis (diethylamino) benzophenone in 100 parts by weight of 2-butanone. The photosensitive solution was applied to a TAC film (trade name FUJITAC TD-80 (80 μm thickness) manufactured by Fuji Photo Film Co., Ltd.) with a doctor blade so as to have a film thickness of about 30 μm, and dried to obtain a recording medium.

An argon laser (363.5 nm) was used as a light source, and the light spread by the lens was exposed from the surface of the recording material through the ground glass 15 (α = 30 °, 50 mJ / c), heated at 85 ° C. for 5 minutes, and then high pressure The recording medium was fixed by irradiating the entire surface with a mercury lamp to obtain an anisotropic light scattering film. The thickness of the obtained film was 31 μm.
Evaluation was made by measuring transmittance (wavelength range: 400-600 nm) at each angle using a spectrophotometer manufactured by Shimadzu Corporation. The results (total wavelength average transmittance) are shown in Table 1.
Moreover, when the adhesiveness with a base material was evaluated by the crosscut tape peel test, it was 100/100 and was favorable.
<Example 2>
Example of using phenoxy resin (product name PKHB, product name PKHB, weight average molecular weight 32,000) instead of phenoxy resin (product name Biscoat 1256, weight average molecular weight 51,000) made by Japan Epoxy Resin Co., Ltd. The same operation as in Example 1 was performed to obtain an anisotropic light scattering film. The thickness of the obtained film was 33 μm. The results are shown in Table 1.
Moreover, when the adhesiveness with a base material was evaluated by the crosscut tape peel test, it was 100/100 and was favorable.

<Example 3>
Instead of phenoxy resin (Inchem Corp, trade name PKHH, weight average molecular weight 52,000), phenoxy resin (Japan Epoxy Resin Co., Ltd., trade name biscoat 1256, weight average molecular weight 51,000) was used, and TAC film ( The product was applied to Fuji Photo Film Co., Ltd. (trade name: Fujitac TD-80, thickness: 80 μm) and dried so that the dry film thickness was about 25 μm. Except for the above, the same operation as in Example 1 was carried out to obtain an anisotropic light scattering film. The obtained film had a thickness of 25 μm. Table 1 shows the results of the total wavelength transmittance at each angle.

Moreover, when the adhesiveness with a base material was evaluated by the crosscut tape peel test, it was 100/100 and was favorable.
<Example 4>
1,4-bis {[((3-ethyl-3-oxetanyl)) instead of 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexyl carboxylate (trade name Araldite CY179 manufactured by Nippon Specialty Chemicals Co., Ltd.) An anisotropic light scattering film was obtained in the same manner as in Example 1 except that methoxy] methyl} benzene (trade name OXT-121, manufactured by Toagosei Co., Ltd.) was used. The obtained film had a thickness of 28 μm. Table 1 shows the results of the total wavelength transmittance at each angle.

Moreover, when the adhesiveness with a base material was evaluated by the crosscut tape peel test, it was 100/100 and was favorable.
<Example 5>
Instead of (4-methylphenyl) [4- (2-methylpropyl) phenyl] iodonium hexafluorophosphate (manufactured by Ciba Specialty Chemicals Co., Ltd., trade name IRGACURE250), triallylsulfonium hexafluorophosphate (Daicel UCB) (Trade name: UVACURE1591) manufactured by KK, and instead of 4,4′-bis (diethylamino) benzophenone, 9,10-dibutoxyanthracene is used, and krypton is used instead of an argon laser (363.5 nm) as a light source. An anisotropic light scattering film was obtained by operating in the same manner as in Example 1 except that the laser (413 nm) was used. The obtained film had a thickness of 31 μm. The results are shown in Table 1.

＜比較例１＞
３，４−エポキシシクロヘキシルメチル−３’，４’−エポキシシクロヘキサンカルボキシレート（日本スペシャリティケミカルズ（株）製商品名アラルダイトＣＹ１７９）の代わりに液状ビスフェノールＡ型エポキシ樹脂（ジャパンエポキシジレン（株）製商品名 エピコート８２８ エポキシ当量１８４〜１９４）を使う以外は実施例１と同様にして操作し、異方性光散乱性フィルムの作製を試みた。しかしながら散乱性が発現しなかった。
＜比較例２＞
フェノキシ樹脂（ジャパンエポキシレジン（株）製、商品名ビスコート１２５６、重量平均分子量５１，０００）の代わりにエポキシ樹脂（ジャパンエポキシレジン（株）製、商品名エピコート１００７、重量平均分子量２，９００）を用い、ＴＡＣフィルム（富士写真フィルム（株）製 商品名フジタックＴＤ−８０ 厚み８０μｍ）に乾燥膜厚が約３０μｍとなるように塗布、乾燥した。前記以外は実施例１と同様にして操作し、異方性光散乱性フィルムを得た。得られた当該フィルムの厚みは３０μｍであった。

<Comparative Example 1>
Instead of 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate (trade name Araldite CY179, manufactured by Nippon Specialty Chemicals Co., Ltd.), liquid bisphenol A type epoxy resin (trade name, manufactured by Japan Epoxy Diylene Co., Ltd.) An anisotropic light-scattering film was produced in the same manner as in Example 1 except that Epicoat 828 (epoxy equivalents 184 to 194) was used. However, scattering was not expressed.
<Comparative example 2>
Instead of phenoxy resin (Japan Epoxy Resin Co., Ltd., trade name Biscote 1256, weight average molecular weight 51,000), epoxy resin (Japan Epoxy Resin Co., Ltd. trade name Epicoat 1007, weight average molecular weight 2,900) was used. The TAC film (Fuji Photo Film Co., Ltd., trade name Fujitac TD-80, thickness 80 μm) was applied and dried so that the dry film thickness was about 30 μm. Except for the above, the same operation as in Example 1 was carried out to obtain an anisotropic light scattering film. The obtained film had a thickness of 30 μm.

  Moreover, when the adhesiveness with a base material was evaluated by the crosscut tape peel test, it peeled from the base material at 0/100.

It is explanatory drawing which shows the light-scattering film of this invention, the left is a top view and the right is sectional drawing. It is explanatory drawing which shows the light-scattering film of this invention, the left is a top view and the right is sectional drawing. The graph which shows an example of the incident angle dependence which the light-scattering film of this invention has. It is a figure explaining the anisotropy of the light scattering which the light-scattering film of this invention has. It is explanatory drawing which shows an example of the optical system which produces the light-scattering film of the structure shown in FIG. 1 using a mask pattern. It is explanatory drawing which shows an example of the optical system which produces the light-scattering film of the structure shown in FIG. 2 using a speckle pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light-scattering film 2 ... Illumination light incident from the scattering direction 3 ... Illumination light incident from the transmission direction 4 ... Plot of measured haze value 5 ... Photosensitive material 6 ... UV light source 7 ... Collimate optical system 8 ... Parallel light 9 ... Mask master 10 ... Glass substrate 11 ... Chrome pattern 12 ... Optical fiber 13 ... Laser light source 14 ... Laser light 15 ... Ground glass 16 ... Beam expander 17 ... Collimator

Claims (8)

  The thermoplastic resin comprising at least a thermoplastic resin (A), a compound (B) having at least one cationic polymerizable group in the molecule, and a photopolymerization initiator (C) that generates cationic species by actinic radiation. An anisotropic light-scattering film composition, wherein there is a difference between the refractive index of (A) and the refractive index of the compound (B) having the cationic polymerizable group.   2. The composition for anisotropic light scattering film according to claim 1, wherein the thermoplastic resin (A) is composed of either a bisphenol A type phenoxy resin or a bisphenol F type phenoxy resin.   The compound (B) having a cationic polymerizable group is composed of at least one compound selected from a compound having an oxirane ring, a compound having an oxetane ring, or a vinyl ether compound. The composition for anisotropic light-scattering films according to claim 1.   The amount of the compound (B) having a cationic polymerizable group is in the range of 10 to 300 parts by weight with respect to 100 parts by weight of the thermoplastic resin (A). The composition for anisotropic light-scattering films as described in 2.   The composition for anisotropic light scattering film according to claim 2, wherein the thermoplastic resin (A) has a weight average molecular weight in the range of 10,000 to 100,000.   The resin layer which consists of a composition for anisotropic light-scattering films in any one of Claims 1-5 is provided in a base material, The part from which a refractive index differs irregularly inside a resin layer by exposing this resin layer. An anisotropic light-scattering film, wherein a light-and-dark part having a high and low refractive index is formed by being distributed in various shapes and thicknesses.   The anisotropic light-scattering film according to claim 6, wherein the portions having different refractive indexes have a structure distributed in a layered manner inclined with respect to the thickness direction of the resin layer.   The anisotropic light scattering film according to claim 6 or 7, wherein the substrate is a plastic film.

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