KR20100109475A - Light diffusing layer and light diffusing sheet - Google Patents

Abstract

PURPOSE: A light diffusing layer and a light diffusing sheet are provided to have excellent light transmitting property and light diffusing property to be used in lighting fixture, lighting signboard, transmitting screen, and a liquid crystal display. CONSTITUTION: A light diffusing layer comprises the binder resin and the silicon resin particle. The amount of the silicon resin particle is approximately 10 to 600 mass for the binder resin 100 mass. The composition containing the binder resin and the silicon resin particle is spread on the transparent support body.

Description

Light diffusing layer and light diffusing sheet {LIGHT DIFFUSING LAYER AND LIGHT DIFFUSING SHEET}

The present invention relates to a light diffusing layer for use in a light diffusing sheet useful for lighting fixtures, lighting signs, transmissive screens, liquid crystal displays, and the like and a light diffusing sheet having the light diffusing layer.

As a light diffusing member used for a backlight of a liquid crystal display, a light diffusing plate and a light diffusing sheet are used. In large-sized displays, in particular, a light diffusing plate is often used because light transmittance and light diffusivity are required. On the other hand, in a small display, since light weight and thinning are especially required, a light-diffusing sheet is often used. In recent years, the weight reduction and thickness reduction are calculated | required also in a large display, and the light diffusive sheet with high light transmittance and light diffusivity is calculated | required.

As a light-diffusion agent used for a light-diffusion member, For example, inorganic fine powders, such as calcium carbonate, barium sulfate, aluminum hydroxide, a zirconium oxide, lithium fluoride, a calcium fluoride, talc, a silica; Organic fine powders such as fluororesin, epoxy resin, polyethylene, acrylic resin, polystyrene, nylon and phenol resin; Silicone resin particle is mentioned. Silicone resin particles are optimal in terms of light transmittance and light diffusivity.

As a light diffusing sheet, the light diffusing sheet (refer patent documents 1-4 etc.) which consist of a resin composition which mix | blended the light diffusing agent, for example, and the light diffusing layer which disperse | distributed the light diffusing agent are laminated | stacked on a transparent support body. The light diffusing sheet (refer patent document 5 etc.) formed is well-known. Compared with the former, the latter is advantageous in terms of resource saving and low cost since the amount of the light diffusing agent can be reduced.

Japanese Patent Laid-Open No. 2008-65142 Japanese Patent Laid-Open No. 2006-037008 Japanese Patent Laid-Open No. 2000-226486 Japanese Patent Laid-Open No. 2006-010819 Japanese Patent Publication No. 9-197109

In the case where the silicone resin particles are used as the light diffusing agent in these light diffusing sheets, the particles easily fall off from the light diffusing sheet, and in particular, when the light diffusing sheet is rolled around and transported, The light diffusing sheet has a problem that the surface of the light diffusing sheet itself is damaged, and the latter light diffusing sheet is scratched on the surface of the light diffusing layer or the surface of the transparent support.

This invention is made | formed in view of the said situation, and an object of this invention is to provide the light diffusing layer which mix | blended the silicone resin particle which is hard to fall off, and the light diffusing sheet which has this light diffusing layer.

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, the present inventors earnestly examined and came to complete this invention. That is, the present invention firstly,

In the light diffusing layer containing the binder resin and the silicone resin particles,

The silicone resin particles contain R ¹ SiO _3/2 units (wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms) of 70 to 100 mol% of all siloxane units, and an organic solvent Is insoluble in the surface, and has at least one organic group selected from the group consisting of an aryl group, an alkenyl group, an acryloyloxy group and a methacryloyloxy group on the surface, and has a light diffusivity which is a spherical particle having a volume average particle diameter of 0.5 to 20 μm. Provide a layer.

Secondly, the present invention provides a light diffusing sheet having the light diffusing layer and a transparent support, on which the light diffusing layer is laminated on the transparent support.

Since the light diffusing sheet of the present invention is lightweight, thin, and is excellent in light transmittance and light diffusing property, the light diffusing sheet can be widely used in lighting equipment, lighting signs, transmissive screens, liquid crystal displays and the like. Moreover, since the fall of the silicone resin particle is suppressed low from the light diffusing layer of this invention, the light diffusing sheet of this invention is hard to be damaged at the time of transport etc.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

[Binder Resin]

The binder resin used in the light diffusing layer of the present invention is not particularly limited as long as it is a transparent resin, and examples thereof include polyesters such as polyethylene terephthalate and polyethylene naphthalate; Acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, polymethyl acrylate, and polyethyl acrylate; Polycarbonate resins; polystyrene; Polyimide resins; Polyolefins such as polyethylene and polypropylene, polycycloolefins; Polyurethane resins; Triacetate cellulose; and the like. Among them, acrylic resins are preferred in terms of weather resistance.

[Silicone Resin Particles]

The silicone resin particles used in the light diffusing layer of the present invention contain R ¹ SiO _3/2 units (wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms) and 70 of the total siloxane units. To 100 mol%, insoluble in organic solvents, having at least one organic group selected from the group consisting of aryl groups, alkenyl groups, acryloyloxy groups, and methacryloyloxy groups on the surface, with a volume average particle size of 0.5 to 20 μm spherical particles. More specifically, the silicone resin particles, R ¹ SiO _3/2 units and from 70 to 100 mol%, R ¹ ₂ SiO _2/2 units, R _{¹ 3} SiO _^1/2 units and SiO _4/2 units (wherein, R <^1> is the thing which consists of 0-30 mol% of at least 1 sort (s) of structural unit chosen from the group which consists of the above).

The formula of R ¹ is unsubstituted or substituted with 1 to 20 carbon atoms, preferably from group 1 of 1 to 6 hydrocarbons, examples of the R ^1, for example a methyl group, an ethyl group, a propyl group, a butyl group, Pen Alkyl groups, such as a methyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, tridecyl group, tetradecyl group, hexadecyl group, an octadecyl group, and an acyl group; Cycloalkyl groups such as cyclobutyl group, cyclopentyl group and cyclohexyl group; Alkenyl groups such as vinyl group and allyl group; Aryl groups, such as a phenyl group and a tolyl group; aralkyl groups such as β-phenylpropyl group; And monovalent hydrocarbon groups in which at least a part of the hydrogen atoms bonded to carbon atoms of these groups is substituted with functional groups such as amino groups, epoxy groups, acryloyloxy groups, methacryloyloxy groups, mercapto groups and cyano groups, for example The monovalent hydrocarbon group substituted by the methacryloyloxy group, such as the monovalent hydrocarbon group substituted by the acryloyloxy group, such as acryloyloxypropyl group, and the methacryloyloxypropyl group, etc. are mentioned. Among these, R ¹ in the silicone resin particles is independently selected from the group consisting of a monovalent hydrocarbon group substituted with a methyl group or an aryl group, an alkenyl group, an acryloyloxy group and a methacryloyloxy group. At least one group, provided that at least a portion of R ¹ present on the surface of the silicone resin particles is substituted with a monovalent hydrocarbon group and a methacryloyloxy group substituted with an aryl group, alkenyl group, acryloyloxy group It is preferable that it is at least one group selected from the group consisting of monovalent hydrocarbon groups.

In the above silicone resin particles, R ¹ SiO content of the _3/2 siloxane units has inde entire 70 to 100 mol% of the units constituting the silicone resin particles, and preferably 90 to 100 mol%. Likely to be to obtain spherical particles having excellent characteristics is difficult because the content is increased when the content of the siloxane units other than the less than 70 mol% when R ¹ SiO _3/2 units. For example, R ¹ ₂ SiO _2/2 units increases, to obtain particles of a spherical tends to be troubled, silicone resin particles obtained is also easier and becomes higher the cohesion, it is easy to deteriorate the dispersibility in binder resin and. When there are more SiO _4/2 units, the silicone resin particles obtained tend to have a higher refractive index and a lower light diffusivity. When the number of R ¹ ₃ SiO _1/2 units increases, the resulting silicone resin particles tend to have a low degree of polymerization and easily dissolve in an organic solvent.

In the silicone resin particles, at least one member selected from the group consisting of R ¹ ₂ SiO _2/2 units, R ¹ ₃ SiO _1/2 units, and SiO _4/2 units (wherein R ¹ is as described above) The structural unit mentioned above is an arbitrary structural unit, and its content is 0-30 mol% among all the siloxane units which comprise the said silicone resin particle, Preferably it is 0-10 mol%.

The said silicone resin particle is insoluble in the organic solvent. As described below, the light diffusing layer is formed by a method of applying a composition containing a binder resin and silicone resin particles to a transparent support. At this time, an organic solvent is usually used as the solvent for dissolving the binder resin, but the silicone resin particles need not be dissolved in the organic solvent so as to maintain the surface distribution of the organic groups and the shape and size of the particles themselves in the organic solvent. . As an organic solvent, For example, alcohol, such as methanol, ethanol, isopropyl alcohol; Aliphatic hydrocarbons such as hexane, heptane, octane, ligroin, and industrial gasoline; Aromatic hydrocarbons such as toluene, benzene and xylene; Chlorinated solvents such as trichloroethylene, carbon tetrachloride, 1,1,1-trichloroethane and perchloroethylene; Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; Esters such as ethyl acetate, butyl acetate, isobutyl acetate and ethylene glycol monoethyl ether acetate; Ethers such as methoxybutanol, methylmethoxybutanol and ethylene glycol monobutyl ether; Or a combination thereof.

The silicone resin particles need to have at least one organic group selected from the group consisting of aryl groups, alkenyl groups, acryloyloxy groups and methacryloyloxy groups on the surface. If the said silicone resin particle does not have the said organic group on the surface, it will be hard to fix to binder resin, and it will fall easily from a light-diffusing layer. But it may also be that the silicone resin particles are present in the organic group which the siloxane units having a surface, in that the said surface can be efficiently introduced into more groups of the organic, R ¹ SiO _3/2 units (wherein, R ¹ is is present in R ¹ of the same) described above are preferred. As an aryl group which the said silicone resin particle has on the surface, a phenyl group, a tolyl group, etc. are mentioned, for example, A phenyl group is preferable. Moreover, as an alkenyl group which the said silicone resin particle has on the surface, a vinyl group, an allyl group, etc. are mentioned, for example, A vinyl group is preferable.

Although the quantity of the said organic group which the said silicone resin particle has on the surface changes also with the particle diameter of the said silicone resin particle, It is preferable that it is 0.01-10 mol with respect to 100 mol of organic groups other than the said organic group in the said silicone resin particle, More preferably, Preferably from 0.1 to 5 moles. When the said amount is 0.01 mol or more, silicone resin particle | grains are easy to fix to binder resin, and are hard to fall out from a light-diffusing layer. When the amount is 10 mol or less, the adhesion of the silicone resin particles to the binder resin can be improved as the amount is increased.

The volume average particle diameter of the said silicone resin particle is 0.5-20 micrometers normally, Preferably it is 1-10 micrometers. When the volume average particle diameter is less than 0.5 µm or exceeds 20 µm, the light diffusion performance of the light diffusing layer obtained is likely to be lowered. In addition, in this specification, a volume average particle diameter is measured by the Coulter counter method.

The silicone resin particles are spherical particles. In the present specification, not only the shape of the spherical shape, but also the length (aspect ratio) of the longest axis / shortest axis is usually 1 to 4, preferably 1 to 2, more preferably 1 to 1.6, and more preferably Also includes the shape of a modified sphere in the range of 1 to 1.4.

The silicone resin particles, according to known methods, for example, a raw material compound such as an alkoxysilane corresponding to the siloxane units present in the silicone resin particles, of the silicone resin particles to produce R ¹ SiO _3/2 units (wherein , R ¹ is as described above, and can be produced by reacting in the presence of an alkali catalyst in an aqueous medium such as water at a molar ratio of 70 to 100 mol% in the total siloxane units. And the silicone resin particles have R ¹ SiO _3/2 units of from 70 to 100 _{^{mol%, R 1 2 SiO 2/}} 2 units, R _{¹ 3} SiO _^1/2 units and SiO _4/2 units (wherein, R ¹ has the above-described When it consists of 0-30 mol% of 1 or more types of structural units chosen from the group which consists of these, the said silicone resin particle is similarly well-known in each case, for example in each siloxane which exists in the said silicone resin particle. among alkoxy silicone resin particles to the raw material compound, such as silane, produced corresponding to the units, the content of R ¹ SiO _3/2 units and 70 to 100 mole% of all siloxane units, R ¹ ₂ SiO _2/2 units, The content of at least one structural unit selected from the group consisting of R ¹ ₃ SiO _1/2 units and SiO _4/2 units (wherein R ¹ is as described above) is 0 to 30 mol% in the total siloxane units. At the molar ratio of water, such as water From can be prepared by reacting in the presence of an alkali catalyst. Silicon resin particles are an aryl group, an alkenyl group, an organic group is at least one kind of a acryloyloxy group and a methacrylate selected from the group consisting of acryloyloxy group R ¹ SiO _3/2 units (wherein, R ¹ has the surface is the one When present in R <^1> , the manufacture of silicone resin particle can be performed according to the method disclosed by Unexamined-Japanese-Patent No. 2-163127, for example. In this method, the organotrialkoxysilane containing the said organic group is dripped at the aqueous suspension of the silicone resin particle which does not have the said organic group, and is made to react in presence of an alkali catalyst. What is necessary is just to adjust the usage-amount of a raw material compound suitably so that content of each structural unit in the silicone resin particle | grains produced may satisfy | fill said condition. Specific examples of the organotrialkoxysilane containing the organic group include phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, acryloyloxypropyltrimethoxysilane and acrylo Iloxypropyl triethoxysilane, methacryloyloxypropyl trimethoxysilane, methacryloyloxy triethoxysilane, etc. are mentioned.

[Light diffusing layer]

In the present invention, the light diffusing layer contains the binder resin and the silicone resin particles. 10-600 mass parts is preferable with respect to 100 mass parts of binder resin, and, as for the quantity of the silicone resin particle in this light-diffusion layer, More preferably, it is 20-400 mass parts. When the amount is 10 parts by mass or more, the light diffusing layer obtained tends to have sufficient light diffusing performance. When the amount is 600 parts by mass or less, the light diffusing layer obtained can be effectively avoided.

The light diffusing layer is formed by, for example, applying a composition containing a binder resin and silicone resin particles to a transparent support. Moreover, by this method, the light diffusing sheet which has a light diffusing layer and a transparent support body and this light diffusing layer is laminated | stacked on the said transparent support body can be manufactured.

In the above method, the composition can be applied by applying a coating liquid in which a binder resin is dissolved in an organic solvent and dispersing silicone resin particles to a transparent support to form a coating film, and then volatilizing the organic solvent from the coating film. . As an organic solvent, what was illustrated in the said description explaining that the silicone resin particle used by this invention is insoluble in the organic solvent is mentioned. As a coating method, well-known methods, such as the printing method, the spraying method, the dipping method, the roll coater method, the curtain flow method, and the Mayer method, can be used.

When UV curable resin is used as binder resin, it can also harden by giving UV irradiation to the apply | coated composition. In addition, when thermosetting resin is used as binder resin, it can also harden by apply | coating heat processing to the apply | coated composition.

The thickness of the light diffusing layer is preferably larger than the particle diameter of the silicone resin particles so that the silicone resin particles are easily fixed to the binder resin. What is necessary is just to adjust the specific value of the said thickness suitably according to the particle diameter of the silicone resin particle to be used, For example, 1-50 micrometers is preferable, More preferably, it is 2-20 micrometers.

In the light diffusing layer, for example, light diffusing agents, coloring agents, ultraviolet absorbers, dispersion aids, antioxidants, lubricants, mold release agents, nucleating agents, plasticizers, flow improving agents, flame retardants, and antistatic agents other than the silicone resin particles may be used as necessary. , A curing agent and the like can be blended.

[Transparent support]

The transparent support used in the present invention is not particularly limited as long as the material is transparent resin. As such resin, resin illustrated above about binder resin is mentioned, for example. If necessary, a light diffuser, a colorant, an ultraviolet absorber, a dispersing aid, an antioxidant, a lubricant, a mold release agent, a crystal nucleating agent, a plasticizer, a flow improving agent, a flame retardant, an antistatic agent, and the like can be added to the transparent support.

As for the thickness of a transparent support body, 20-1000 micrometers is preferable, More preferably, it is 50-800 micrometers. When the thickness is 20 µm or more, the transparent support is particularly easy to handle in the manufacturing process of the light diffusing sheet. In addition, the light diffusing sheet obtained when the said thickness is 1000 micrometers or less is especially easy to achieve | require required weight reduction and thickness reduction.

[Example]

Hereinafter, the present invention will be described in detail with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

Synthesis Example 1 Synthesis of Silicone Resin Particle-1

804 g of ion-exchange water was thrown into the 2-liter glass flask with an anchor stirring blade, and it was set as water temperature 20 degreeC. 170 g of methyltrimethoxysilane was put into this, and it stirred for 2 hours, maintaining liquid temperature at 20-30 degreeC. During this time, the hydrolysis reaction proceeded to obtain a transparent liquid. After cooling the obtained liquid to 10 degreeC, 6 g of 2.8 mass% ammonia water was thrown in, and it stirred for 1 minute. Then, stirring was stopped and the liquid was left to stand. In this liquid, the condensation reaction proceeded, and after 10 minutes, particles were formed and the liquid became cloudy. Stirring was resumed after 3 hours, and 18 g of 28 mass% ammonia water was added thereto. Subsequently, 2.5 g (methyl trimethoxysilane: phenyltrimethoxysilane (molar ratio) = 100: 1.0 amount) of phenyl trimethoxysilane was added, and it stirred for 1 hour, and condensed phenyl trimethoxysilane. The obtained liquid was heated to 80-85 degreeC, it stirred for 4 hours, and the silicone resin particle dispersion liquid was obtained. The obtained dispersion liquid was solid-liquid separated by the pressure filter, and the cake-like thing was obtained. Subsequently, this cake-like thing was dried in the hot air circulation dryer at the temperature of 105 degreeC, and the obtained dried material was disintegrated with the jet mill, and the silicone resin particle which has a phenyl group on the particle surface was obtained. The obtained silicone resin particle is called silicone resin particle-1.

The electron microscope observation confirmed that the silicone resin particle-1 had a spherical shape and had a particle size of 4 to 8 µm. Silicone resin particle-1 has a particle diameter in the same range as silicone resin particle-5 manufactured in the synthesis example 5 mentioned later, ie, the silicone resin particle which has only methyl group as an organic group, manufactured without post-adding phenyltrimethoxysilane. Was. Since the amount of the phenyltrimethoxysilane added after the addition of the phenyltrimethoxysilane is smaller than that of methyltrimethoxysilane, if the phenyltrimethoxysilane was self-condensed, particles having a particle size smaller than 4 to 8 μm are mixed. Would have been. However, since it was not so, it is suggested that phenyltrimethoxysilane was condensed on the surface of the silicone resin particles having only methyl groups as organic groups.

Silicone resin particle-1 was disperse | distributed to water using surfactant, and the dispersion liquid was obtained. It was 5.6 micrometers when the obtained dispersion liquid was used as a sample and the volume average particle diameter of silicone resin particle-1 was measured by the multisizer 3 (made by Beckman Coulter Co., Ltd.).

In order to test the solubility of the silicone resin particle-1 to toluene, first, 15 g of toluene and 10 g of silicone resin particle-1 were weighed into a glass bottle, shaken for 60 minutes, and then solid-liquid separation was carried out by a pressure filter. Subsequently, 2 g of the obtained filtrate was weighed into a Petri dish, and toluene was volatilized at 105 ° C, but no residue was observed. Therefore, it was confirmed that silicone resin particle-1 was not dissolved in toluene.

Synthesis Example 2 Synthesis of Silicone Resin Particle-2

In Synthesis Example 1, 136 g of methyltrimethoxysilane and 30 g of dimethyldimethoxysilane (methyltrimethoxysilane: dimethyldimethoxysilane (molar ratio) = 80: 20) were used instead of 170 g of methyltrimethoxysilane. Instead of 2.5 g of phenyltrimethoxysilane (amount such that methyltrimethoxysilane: phenyltrimethoxysilane (molar ratio) = 100: 1.0), 1.9 g of vinyltrimethoxysilane (methyltrimethoxysilane and dimethyldimethol) The same as in Synthesis Example 1 except that vinyltrimethoxysilane was condensed instead of condensing phenyltrimethoxysilane using a total of oxysilane: amount of vinyltrimethoxysilane (molar ratio = 100: 1.0). The silicone resin particle which has a vinyl group on the particle surface was obtained. The obtained silicone resin particle is called silicone resin particle-2.

The electron microscope observation confirmed that the silicone resin particle-2 had a spherical shape and had a particle size of 4 to 8 µm. Silicone resin particle-2 had a particle size in the same range as silicone resin particle-5 similarly to silicone resin particle-1. Since the added amount of the post-added vinyltrimethoxysilane is less than the sum of methyltrimethoxysilane and dimethyldimethoxysilane, the particle size produced is 4 when the vinyltrimethoxysilane is self-condensed. It would have been mixed to less than 8 μm. However, since it was not so, it is suggested that the vinyltrimethoxysilane condensed on the surface of the silicone resin particle which has only methyl group as an organic group.

In Example 1, except having used silicone resin particle-2 instead of silicone resin particle-1, it carried out similarly to Example 1, and measured the volume average particle diameter of silicone resin particle-2, and it was 5.7 micrometers.

In Example 1, except that silicone resin particles-2 were used instead of silicone resin particles-1, the solubility of silicone resin particles-2 to toluene was tested in the same manner as in Example 1, and no residue was observed after toluene volatilization. Therefore, it was confirmed that silicone resin particle-2 was not dissolved in toluene.

Synthesis Example 3 Synthesis of Silicone Resin Particles-3

In Synthesis Example 1, 3.0 g of acryloyloxypropyltrimethoxysilane instead of 2.5 g of phenyltrimethoxysilane (the amount of methyltrimethoxysilane: phenyltrimethoxysilane (molar ratio) = 100: 1.0) Instead of condensing phenyltrimethoxysilane using methyltrimethoxysilane: acryloyloxypropyltrimethoxysilane (molar ratio = 100: 1.0), acryloyloxypropyltrimethoxysilane Except condensation, it carried out similarly to the synthesis example 1, and obtained the silicone resin particle which has acryloyloxypropyl group on the particle surface. The obtained silicone resin particle is called silicone resin particle-3.

The electron microscope observation confirmed that silicone resin particle-3 was spherical and had a particle diameter of 4-8 micrometers. Silicone resin particle-3 had a particle size in the same range as silicone resin particle-5 similarly to silicone resin particle-1. Since the amount of the post-added acryloyloxypropyltrimethoxysilane is less than methyltrimethoxysilane, the particle size is different in the resulting particles when the acryloyloxypropyltrimethoxysilane is self-condensed. Smaller than 4-8 μm may have been mixed. However, since it was not so, it is suggested that acryloyloxypropyltrimethoxysilane was condensed on the surface of the silicone resin particles having only methyl groups as organic groups.

In Example 1, except having used silicone resin particle-3 instead of silicone resin particle-1, it carried out similarly to Example 1, and measured the volume average particle diameter of silicone resin particle-3, and it was 5.7 micrometers.

In Example 1, except that silicone resin particle-3 was used instead of silicone resin particle-1, the solubility of silicone resin particle-3 in toluene was tested in the same manner as in Example 1, and no residue was observed after toluene volatilization. Therefore, it was confirmed that silicone resin particle-3 was not dissolved in toluene.

Synthesis Example 4 Synthesis of Silicone Resin Particles-4

15.5 g of methacryloyloxypropyltrimethoxysilane instead of 2.5 g of phenyltrimethoxysilane (amount such that methyltrimethoxysilane: phenyltrimethoxysilane (molar ratio) = 100: 1.0) in Synthesis Example 1 (Methyltrimethoxysilane: methacryloyloxypropyltrimethoxysilane (molar ratio) = 100: 5.0), instead of condensing phenyltrimethoxysilane, methacryloyloxypropyltrimeth A silicone resin particle having methacryloyloxypropyl group on the particle surface was obtained in the same manner as in Synthesis example 1 except that the oxysilane was condensed. The obtained silicone resin particle is called silicone resin particle-4.

The electron microscope observation confirmed that silicone resin particle-4 was spherical and had a particle diameter of 4-8 micrometers. Silicone resin particle-4 had the particle diameter of the same range as silicone resin particle-5 similarly to silicone resin particle-1. Since the added amount of methacryloyloxypropyltrimethoxysilane is less than methyltrimethoxysilane in the post-added methacryloyloxypropyltrimethoxysilane, the resulting particles are self-condensed. Particles smaller than 4 to 8 μm may have been mixed. However, since it was not so, it is suggested that the methacryloyloxypropyl trimethoxysilane condensed on the surface of the silicone resin particle which has only methyl group as an organic group.

In Example 1, except having used silicone resin particle-4 instead of silicone resin particle-1, it carried out similarly to Example 1, and measured the volume average particle diameter of silicone resin particle-4, and it was 5.7 micrometers.

In Example 1, except that silicone resin particles-4 were used instead of silicone resin particles-1, the solubility of silicone resin particles-4 in toluene was tested in the same manner as in Example 1, and no residue was observed after toluene volatilization. Therefore, it was confirmed that silicone resin particle-4 was not dissolved in toluene.

Synthesis Example 5 Synthesis of Silicone Resin Particles-5

In Synthesis Example 1, 2.5 g of phenyltrimethoxysilane (amount such that methyltrimethoxysilane: phenyltrimethoxysilane (molar ratio) = 100: 1.0) was added thereto, stirred for 1 hour, and phenyltrimethoxysilane A silicone resin particle having only a methyl group as an organic group was obtained in the same manner as in Synthesis example 1, except that the operation of condensing the polymer was omitted. The obtained silicone resin particle is called silicone resin particle-5.

The electron microscope observation confirmed that silicone resin particle-5 was spherical and had a particle diameter of 4-8 micrometers.

In Example 1, except having used silicone resin particle-5 instead of silicone resin particle-1, it carried out similarly to Example 1, and measured the volume average particle diameter of silicone resin particle-5, and it was 5.6 micrometers.

In Example 1, except that silicone resin particles-5 were used instead of silicone resin particles-1, the solubility of the silicone resin particles-5 to toluene was tested in the same manner as in Example 1, and no residue was observed after toluene volatilization. Therefore, it was confirmed that silicone resin particle-2 was not dissolved in toluene.

[Examples 1 to 4 and Comparative Example 1]

The coating liquid for following light diffusable layers was manufactured using what was shown in Table 1 as silicone resin particle, and the one side of the transparent support body which consists of a polyester film (brand name: Lumirror T60, thickness 100 micrometers, Toray Corporation make) The coating liquid for light diffusing layer was apply | coated so that it might become set to dry film thickness of 10 micrometers, and the light diffusing sheet which consists of a transparent support body and a light diffusing layer was obtained.

Coating liquid for light diffusing layer (uniform mixture of the following components)

Acryl polyol (acrylic resin, trade name: Acridict A-801P, manufactured by Dainippon Ink Chemical Industries, Ltd.): 14 parts by mass

Isocyanate prepolymer (curing agent, brand name: Takenate D110N, manufactured by Takeda Yakching Kogyo Co., Ltd.): 6 parts by mass

Silicone resin particles: 14 parts by mass

Methyl ethyl ketone: 14 parts by mass

Toluene: 14 parts by mass

Butyl acetate: 7 parts by mass

Measurement of total light transmittance and light diffusion transmittance

The total light transmittance and the light diffusivity of the obtained light diffusing sheet were measured by a turbidimeter (trade name: NDH2000, manufactured by Nippon Denshoku Kogyo Co., Ltd.). The measurement results are shown in Table 1.

Dropout test

By using a friction shoulder tester (brand name: AB-301 COLOR FASTNESS RUBBING TESTER, tester Sangyo Co., Ltd.) at 200 g load with steel wool (brand name: Bonstar No.0000, Nippon Steel Wool Co., Ltd.) After rubbing the surface on the side where the light diffusing layer of the light diffusing layer was formed for 10 round trips, the surface was observed with an optical microscope to confirm whether the silicone resin particles were dropped off.

[evaluation]

The silicone resin particles used in Examples 1 to 4 had a phenyl group, vinyl group, acryloyloxy group or methacryloyloxy group on the particle surface and did not drop off from the light diffusing layer, whereas the silicone resin used in Comparative Example 1 The particles did not have the organic group such as a phenyl group on the particle surface and were dropped from the light diffusing layer.

Claims (7)

In the light diffusing layer containing the binder resin and the silicone resin particles,
The silicone resin particles contain R ¹ SiO _3/2 units (wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 20 carbon atoms) of 70 to 100 mol% of all siloxane units, and an organic solvent Is insoluble in the surface, and has at least one organic group selected from the group consisting of an aryl group, an alkenyl group, an acryloyloxy group and a methacryloyloxy group on the surface, and has a light diffusivity which is a spherical particle having a volume average particle diameter of 0.5 to 20 μm. layer. The method of claim 1, wherein the silicone resin particles have R ¹ SiO _3/2 units of from 70 to 100 _{^{mol%, R 1 2 SiO 2/}} 2 units, R _{¹ 3} SiO _^1/2 units and SiO _4/2 units (wherein And R ¹ is as described above. The light diffusing layer comprising 0 to 30 mol% of at least one structural unit selected from the group consisting of: The monovalent substituted according to claim 1 or 2, wherein R ¹ in the silicone resin particles is independently substituted with a monovalent hydrocarbon group and a methacryloyloxy group substituted with a methyl group or an aryl group, an alkenyl group, and an acryloyloxy group. At least one group selected from the group consisting of hydrocarbon groups, provided that at least part of R ¹ present on the surface of the silicone resin particles is a monovalent hydrocarbon group and a meta substituted with an aryl group, alkenyl group, acryloyloxy group, and meta The light diffusing layer which is at least 1 sort (s) of group chosen from the group which consists of monovalent hydrocarbon group substituted by the cycloyloxy group. The light diffusing layer according to claim 1 or 2, wherein the aryl group is a phenyl group and the alkenyl group is a vinyl group. According to claim 1 or 2, wherein the light-diffusing group is the organic wherein the silicone resin particles have a surface R ¹ SiO _3/2 units being present in the R ¹ (where, R ¹ are as described above) castle layer. The light diffusing layer according to claim 1 or 2, wherein the binder resin is an acrylic resin. The light diffusing sheet which has the light-diffusion layer and transparent support of Claim 1 or 2, and this light-diffusion layer is laminated | stacked on the said transparent support body.