JP5209283B2 - Resin composition for light diffusion plate and light diffusion plate - Google Patents
Resin composition for light diffusion plate and light diffusion plate Download PDFInfo
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- JP5209283B2 JP5209283B2 JP2007305701A JP2007305701A JP5209283B2 JP 5209283 B2 JP5209283 B2 JP 5209283B2 JP 2007305701 A JP2007305701 A JP 2007305701A JP 2007305701 A JP2007305701 A JP 2007305701A JP 5209283 B2 JP5209283 B2 JP 5209283B2
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
- C08L25/02—Homopolymers or copolymers of hydrocarbons
- C08L25/04—Homopolymers or copolymers of styrene
- C08L25/08—Copolymers of styrene
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/16—Solid spheres
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
- C08L33/04—Homopolymers or copolymers of esters
- C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
- C08L33/10—Homopolymers or copolymers of methacrylic acid esters
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/02—Diffusing elements; Afocal elements
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
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- Extrusion Moulding Of Plastics Or The Like (AREA)
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Description
本発明は、高耐光、高耐熱、低吸水、高輝度、高光拡散である光拡散板及びそれに使用される樹脂組成物に関する。 The present invention relates to a light diffusing plate having high light resistance, high heat resistance, low water absorption, high luminance, and high light diffusion, and a resin composition used therefor.
樹脂を主材料とする光拡散透過性を有する光拡散板は、均一な輝度面が得られる。このため、光拡散板は、照明カバー、内部照明式看板、透過型ディスプレイなどの用途に広く用いられている。近年では、液晶ディスプレイあるいは液晶テレビの直下型バックライト用の面光源体としての光拡散板の需要が伸びている。 A light diffusing plate having a light diffusibility and a resin as a main material can obtain a uniform luminance surface. For this reason, the light diffusing plate is widely used for applications such as an illumination cover, an internal illumination signboard, and a transmissive display. In recent years, the demand for a light diffusing plate as a surface light source body for a direct backlight of a liquid crystal display or a liquid crystal television is increasing.
光拡散板は、上記の機能を最適に発揮するために、光線をできる限り直進させることなく散乱させるとともに、できる限り散乱による光透過損失を抑えることが求められる。 The light diffusing plate is required to scatter the light ray without making it travel as straight as possible and to suppress the light transmission loss due to the scattering as much as possible in order to exhibit the above functions optimally.
このような要求特性を発現させる光拡散板を得るために、透明樹脂に炭酸カルシウム、硫酸バリウム、酸化チタン、酸化ケイ素、タルク、マイカ、水酸化アルミニウム、酸化マグネシウムなどの無機系粒子を添加する方法、スチレン系重合体粒子、アクリル系重合体粒子、シロキサン系重合体粒子などの部分的に架橋したポリマー微粒子を添加する方法、あるいはこれらを併用する方法により、添加物によって光を散乱させる手法が採用されてきた（例えば、特許文献１〜３参照）。 A method of adding inorganic particles such as calcium carbonate, barium sulfate, titanium oxide, silicon oxide, talc, mica, aluminum hydroxide, magnesium oxide to a transparent resin in order to obtain a light diffusing plate that exhibits such required characteristics Adopting a method that scatters light with additives by adding partially cross-linked polymer particles such as styrene polymer particles, acrylic polymer particles, siloxane polymer particles, or a combination of these. (For example, see Patent Documents 1 to 3).
光拡散板に用いられる透明樹脂として、アクリル樹脂、ポリカーボネート、そしてメタクリル酸メチル‐スチレン共重合樹脂等が挙げられるが、これらは、耐熱性、硬度、吸水性の面で満足する物性を有していない。また、特許文献４、５では、スチレンとメタクリル酸の共重合樹脂に拡散剤を配合する手法が開示されており、耐熱性の向上に関しては改善されてきているが、スチレン系樹脂が主成分であるため、耐光性に劣り、別途紫外線吸収層を設けるなどの手法が併用されている。 Examples of the transparent resin used for the light diffusing plate include acrylic resin, polycarbonate, and methyl methacrylate-styrene copolymer resin, which have satisfactory physical properties in terms of heat resistance, hardness, and water absorption. Absent. Further, Patent Documents 4 and 5 disclose a method of blending a diffusing agent with a copolymer resin of styrene and methacrylic acid, which has been improved in terms of improving heat resistance, but styrene resin is the main component. Therefore, it is inferior in light resistance, and a technique such as providing a separate ultraviolet absorbing layer is also used in combination.
最近、液晶ディスプレイあるいは液晶テレビの部材特性の向上が図られている中、アクリル樹脂を用いた光拡散板は高吸水性を有するため、バックライト点灯時の反りが問題となっている。 Recently, improvement of member characteristics of a liquid crystal display or a liquid crystal television has been attempted. Since a light diffusing plate using acrylic resin has high water absorption, warpage at the time of lighting a backlight is a problem.
また、ディスプレイ使用中、バックライトが発熱するため、その直上にある光拡散板には耐熱性も求められる。しかし、従来のアクリル樹脂は、その特性を満足するものではない。 Further, since the backlight generates heat during use of the display, the light diffusion plate directly above it is also required to have heat resistance. However, conventional acrylic resins do not satisfy the characteristics.
さらには、耐熱スチレン樹脂は吸水性と耐熱性を改善するために有効であるが、耐光性が劣り、長期のバックライトの照射で着色や機械物性の低下が発生し、ディスプレイとした時の色むらやワレが発生する。 In addition, heat-resistant styrene resins are effective for improving water absorption and heat resistance, but they are inferior in light resistance, causing coloration and deterioration of mechanical properties due to long-term backlight irradiation, resulting in color when used as a display. Unevenness and cracking occur.
上記のように従来の光拡散板は、高耐光、高輝度、高光拡散、低吸水を必要とする光拡散板としての機能を十分に満足するものではない。 As described above, the conventional light diffusion plate does not sufficiently satisfy the function as a light diffusion plate requiring high light resistance, high luminance, high light diffusion, and low water absorption.
本発明は、上記の課題に鑑みてなされたものであり、高耐光、高耐熱、高低吸水、高輝度、高光拡散である光拡散板を提供することを目的とする。 The present invention has been made in view of the above problems, and an object of the present invention is to provide a light diffusing plate having high light resistance, high heat resistance, high and low water absorption, high luminance, and high light diffusion.
本発明者は、鋭意検討した結果、特定の組成を有するメタクリル酸メチル／メタクリル酸／スチレン共重合樹脂と拡散剤からなる光拡散板用樹脂組成物を用いることにより成形された光拡散板が上記目的を達成できることを見出し、本発明を完成するに至った。 As a result of intensive studies, the present inventors have found that a light diffusing plate formed by using a resin composition for a light diffusing plate comprising a methyl methacrylate / methacrylic acid / styrene copolymer resin having a specific composition and a diffusing agent is the above. The inventors have found that the object can be achieved and have completed the present invention.
本発明に係る光拡散板用樹脂組成物は、メタクリル酸メチル単位１０〜４０重量％、メタアクリル酸単位２〜２０重量％及びスチレン単位４０〜９２重量％の割合で構成され、重量平均分子量の範囲が８００００〜３０００００である共重合樹脂１００重量部に対して、光拡散剤０．１〜１０．０重量部配合してなることを特徴とする。 The resin composition for a light diffusing plate according to the present invention comprises 10 to 40% by weight of methyl methacrylate units, 2 to 20% by weight of methacrylic acid units, and 40 to 92% by weight of styrene units, and has a weight average molecular weight. It is characterized by blending 0.1 to 10.0 parts by weight of a light diffusing agent with respect to 100 parts by weight of a copolymer resin having a range of 80,000 to 300,000.
また、本発明は上記光拡散板用樹脂組成物を溶融押出成形又は射出成形により、厚さ０．５〜３ｍｍの板状に成形された光拡散板に関する。 The present invention also relates to a light diffusing plate obtained by molding the above resin composition for a light diffusing plate into a plate having a thickness of 0.5 to 3 mm by melt extrusion molding or injection molding.
本発明の光拡散板用樹脂組成物に使用する共重合樹脂は、完全混合型反応器を用いた連続塊状重合法又は連続溶液重合法を利用することが組成や分子量の均一性と良好な外観を保持する上から望ましいが、バッチ式の塊状又は溶液重合でも可能である。重合時には開始剤を存在させることが好ましく、開始剤としては、通常のラジカル重合に使用する過酸化物及び／又はアゾ化合物が使用可能である。また、分子量を調節するためにアルキルメルカプタンのような連鎖移動剤を適量添加しても差し支えない。重合終了後は、常法により脱揮、ペレット化等の処理を行って本発明の光拡散板用樹脂組成物に使用する共重合樹脂を得ることができる。 The copolymer resin used in the resin composition for a light diffusing plate of the present invention uses a continuous bulk polymerization method or a continuous solution polymerization method using a fully mixed reactor, and composition and molecular weight uniformity and good appearance Although it is desirable from the viewpoint of maintaining the viscosity, batch-type bulk or solution polymerization is also possible. An initiator is preferably present at the time of polymerization, and as the initiator, a peroxide and / or an azo compound used for normal radical polymerization can be used. Further, an appropriate amount of a chain transfer agent such as an alkyl mercaptan may be added to adjust the molecular weight. After completion of the polymerization, a copolymer resin used in the resin composition for a light diffusing plate of the present invention can be obtained by performing treatments such as devolatilization and pelletization by a conventional method.
共重合樹脂を構成する単位として、メタクリル酸メチル単位を１０〜４０重量％、好ましくは１０〜２５重量％含み、メタアクリル酸単位を２〜２０重量％、好ましくは４〜１５重量％含み、スチレン単位を４０〜８８重量％、好ましくは５５〜６０重量％含む。メタクリル酸メチル単位の割合が１０重量％未満であると耐光性能が劣り、４０重量％を超えると高吸湿性を有するため、反りが起きやすい材料となる。メタアクリル酸単位の割合が２重量％未満であると耐熱性が低すぎ、２０重量％を超えると重合時に架橋によるゲル発生量が過剰で表面にハシリのあるシートとなりやすい。また、スチレン単位の割合が４０重量％未満であると高吸湿性を有するため、反りが起こりやすい材料となり、８８重量％を越えると耐熱性が低くなる。 As a unit constituting the copolymer resin, methyl methacrylate units are contained in an amount of 10 to 40% by weight, preferably 10 to 25% by weight, methacrylic acid units are contained in an amount of 2 to 20% by weight, preferably 4 to 15% by weight, and styrene. The unit is contained in an amount of 40 to 88% by weight, preferably 55 to 60% by weight. When the proportion of the methyl methacrylate unit is less than 10% by weight, the light resistance is inferior, and when it exceeds 40% by weight, the material has a high hygroscopic property, so that the material easily warps. When the proportion of the methacrylic acid unit is less than 2% by weight, the heat resistance is too low. Further, when the proportion of styrene units is less than 40% by weight, the material has high hygroscopicity, so that the material tends to warp, and when it exceeds 88% by weight, the heat resistance is lowered.
共重合樹脂の分子量は、重量平均分子量として８００００〜３０００００の範囲とする。重量平均分子量が８００００未満であると流動性が高くなりすぎて、厚みムラのあるシートとなってしまう。また、重量平均分子量が３０００００を超えると流動性が低くすぎるため、成形困難となる。 The molecular weight of the copolymer resin is in the range of 80,000 to 300,000 as the weight average molecular weight. If the weight average molecular weight is less than 80000, the fluidity becomes too high, resulting in a sheet with uneven thickness. On the other hand, when the weight average molecular weight exceeds 300,000, the fluidity is too low, so that molding becomes difficult.
また、この共重合樹脂のメルトフローレートは、０．５〜３．０g/10minの範囲とすることがよい。好ましくは１．０〜２．５g/10minである。メルトフローレート３．０g/10minより高くなると厚みムラのあるシートとなってしまう。メルトフローレート０．５g/10min未満になると流動性が低すぎるため、成形困難となる。 The melt flow rate of this copolymer resin is preferably in the range of 0.5 to 3.0 g / 10 min. Preferably it is 1.0-2.5 g / 10min. When the melt flow rate is higher than 3.0 g / 10 min, a sheet with uneven thickness is obtained. When the melt flow rate is less than 0.5 g / 10 min, the fluidity is too low, and molding becomes difficult.
また、この共重合樹脂のビカット軟化温度は、１０３℃以上、好ましくは１０５〜１３０℃であることがよい。ビカット軟化温度１０３℃未満であるとバックライトの発熱に対する耐熱性が低いため、基材の変形等が発生しやすくなる。 The Vicat softening temperature of the copolymer resin is 103 ° C. or higher, preferably 105 to 130 ° C. If the Vicat softening temperature is less than 103 ° C., the heat resistance of the backlight against heat generation is low, so that the substrate is likely to be deformed.
また、この共重合樹脂は、吸水率０．３０％以下、好ましくは０．２５％以下であることがよい。吸水率０．３０％を超えると吸水による反りの問題が発生しやすくなる。 The copolymer resin has a water absorption of 0.30% or less, preferably 0.25% or less. If the water absorption exceeds 0.30%, the problem of warpage due to water absorption tends to occur.
原料モノマーとしては、メタクリル酸メチル、メタクリル酸及びスチレンを含む原料が使用される。これらの使用割合は、メタクリル酸メチル単位、メタクリル酸単位及びスチレン単位が上記割合となる共重合樹脂が得られるように重合性を考慮しながら使用する。なお、共重合樹脂は透明度を高くするように製造する。この原料モノマーの使用割合と共重合樹脂中の各構成単位の割合はほぼ対応する。 As the raw material monomer, a raw material containing methyl methacrylate, methacrylic acid and styrene is used. These usage ratios are used in consideration of polymerizability so as to obtain a copolymer resin in which methyl methacrylate units, methacrylic acid units and styrene units have the above ratios. The copolymer resin is manufactured so as to increase transparency. The ratio of the raw material monomer used corresponds substantially to the ratio of each structural unit in the copolymer resin.
また、この共重合樹脂には、本発明の目的を外れない範囲で、少量の他の構成単位を存在させることができる。このような構成単位を与える単量体として、スチレンの他、置換スチレン類の１種以上を組み合わせて用いることもできる。該置換スチレン類としては、例えばクロロスチレン、ブロモスチレンのようなハロゲン化スチレン類、ビニルトルエン、α−メチルスチレンのようなアルキルスチレン類などが挙げられる。更に、メタクリル酸メチル以外の（メタ）アクリル酸エステル類の１種以上を組み合わせて用いることもできる。（メタ）アクリル酸エステル類としては、メタクリル酸エチル、メタクリル酸ブチル、メタクリル酸シクロヘキシル、メタクリル酸オクタデシル、メタクリル酸フェニル、メタクリル酸ベンジル、メタクリル酸オクタデシル、メタクリル酸２−エチルヘキシルなどのようなメタクリル酸エステル類、アクリル酸メチル、アクリル酸エチル、アクリル酸ブチル、アクリル酸シクロヘキシル、アクリル酸フェニル、アクリル酸ベンジル、アクリル酸２−エチルヘキシルなどのようなアクリル酸エステル類などが挙げられる。 The copolymer resin may contain a small amount of other structural units within the range not departing from the object of the present invention. In addition to styrene, one or more substituted styrenes may be used in combination as the monomer that provides such a structural unit. Examples of the substituted styrenes include halogenated styrenes such as chlorostyrene and bromostyrene, and alkyl styrenes such as vinyltoluene and α-methylstyrene. Further, one or more (meth) acrylic acid esters other than methyl methacrylate can be used in combination. (Meth) acrylic acid esters such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, octadecyl methacrylate, phenyl methacrylate, benzyl methacrylate, octadecyl methacrylate, 2-ethylhexyl methacrylate, etc. Acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and the like.
本発明に係る光拡散板用樹脂組成物は、共重合樹脂１００部（重量部）に対して光拡散剤を０．１〜１０．０部、好ましくは０．２〜５．０部存在させるように配合して得られる。配合量が０．１部未満であると光源の隠蔽性に欠けるため、バックライト光源のイメージに起因する輝度ムラの目立つ光拡散板となる。１０．０部を超えると透過光量が不十分なため、明るさの不足した光拡散板となる。 The resin composition for a light diffusing plate according to the present invention contains 0.1 to 10.0 parts, preferably 0.2 to 5.0 parts of a light diffusing agent with respect to 100 parts (parts by weight) of a copolymer resin. It is obtained by blending as follows. If the blending amount is less than 0.1 part, the light source is not concealed, so that a light diffusion plate with noticeable luminance unevenness due to the image of the backlight light source is obtained. If the amount exceeds 10.0 parts, the amount of transmitted light is insufficient, resulting in a light diffusing plate with insufficient brightness.
光拡散剤としては、公知の微粒子を使用することができるが、好ましくは粒径１〜１０μｍの部分的に架橋したシロキサン系重合体粒子、アクリル系重合体粒子又は炭酸カルシウムである。これらの拡散剤は１種のみを使用しても、数種を使用してもよい。また、その他の拡散剤として、硫酸バリウム、酸化チタン、酸化ケイ素、タルク、マイカ、水酸化アルミニウム、酸化マグネシウムなどの無機系粒子やスチレン系重合体粒子を併用することもできるが、光拡散剤の５０重量％未満にとどめることがよい。 As the light diffusing agent, known fine particles can be used, and preferably, partially crosslinked siloxane polymer particles, acrylic polymer particles or calcium carbonate having a particle diameter of 1 to 10 μm. These diffusing agents may be used alone or in combination. In addition, as other diffusing agents, inorganic particles such as barium sulfate, titanium oxide, silicon oxide, talc, mica, aluminum hydroxide, magnesium oxide and styrene polymer particles can be used in combination. It is better to keep it below 50% by weight.
共重合樹脂と光拡散剤の混合は公知の方法で均一混合物となるように行うことができる。このようにして得られる光拡散板用樹脂組成物は、有利には押出成形又は射出成形して厚さ０．５〜３mmの板状に成形する。厚さが０．５mm未満であると、バックライト用拡散板としての強度の確保が困難となり、厚さが３mmを越えると、拡散板重量が大きくなるため、大型化、薄型化への対応が困難となる。これを、そのまま又は所定サイズに切断又は表面処理等をして、本発明に係る光拡散板とする。しかし、その製造方法は、本発明の目的を満足できれば、特に限定されるものではない。 The copolymer resin and the light diffusing agent can be mixed by a known method so as to form a uniform mixture. The resin composition for a light diffusing plate thus obtained is preferably formed into a plate having a thickness of 0.5 to 3 mm by extrusion molding or injection molding. If the thickness is less than 0.5 mm, it will be difficult to ensure the strength as a diffusion plate for backlights. If the thickness exceeds 3 mm, the weight of the diffusion plate will increase. It becomes difficult. This is cut or surface-treated as it is or with a predetermined size to obtain a light diffusing plate according to the present invention. However, the production method is not particularly limited as long as the object of the present invention can be satisfied.
本発明の光拡散板は、上記光拡散板用樹脂組成物から構成されていれば、単一の層で構成されてもよいし、二層以上の多層で構成されてもよい。 As long as the light diffusing plate of the present invention is composed of the above resin composition for light diffusing plate, it may be composed of a single layer or may be composed of two or more layers.
本発明の光拡散板は、メタクリル酸メチル／メタクリル酸／スチレンの三元系共重合樹脂と拡散剤を使用することで、高耐光、高耐熱、高低吸水、高輝度、高光拡散等の物性を実現するものであるが、この目的を著しく阻害しない範囲であれば、必要に応じて、帯電防止剤、酸化防止剤、難燃剤、光安定剤、紫外線吸収剤、蛍光増白剤などの種々の添加剤を使用することもできる。 The light diffusion plate of the present invention has physical properties such as high light resistance, high heat resistance, high and low water absorption, high brightness, and high light diffusion by using a terpolymer copolymer of methyl methacrylate / methacrylic acid / styrene and a diffusing agent. As long as this objective is not significantly impaired, various kinds of antistatic agents, antioxidants, flame retardants, light stabilizers, ultraviolet absorbers, fluorescent brighteners, etc. Additives can also be used.
本発明の光拡散板は、光拡散性と光透過性のバランスが要求される用途、主として液晶ディスプレイあるいは液晶テレビの直下型バックライト用拡散板として用いられ、特に、大型、薄型化に伴い、高耐光、耐熱性、高硬度を要求される用途に好適である。そして、本発明に係る光拡散板用樹脂組成物から得られる光拡散板は、高耐熱、低吸水であり、耐光性に優れる。 The light diffusing plate of the present invention is used as a diffusing plate for a direct backlight of a liquid crystal display or a liquid crystal television, mainly used in applications where a balance between light diffusibility and light transmittance is required. Suitable for applications requiring high light resistance, heat resistance, and high hardness. And the light diffusing plate obtained from the resin composition for light diffusing plates which concerns on this invention is high heat resistance, low water absorption, and is excellent in light resistance.
以下、実施例により本発明を具体的に説明するが、本発明はこれら実施例に限定されるものではない。 EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
光拡散板用樹脂組成物に使用される共重合樹脂の物性の測定は、以下の方法により行なった。
（１）分子量
ゲルパーミエーションクロマトグラフィーを使用しポリスチレン換算の重量平均分子量を測定した。
（２）共重合体中の各単位組成
共重合体のメタクリル酸メチル単位とスチレン単位組成は熱分解型ガスクロマトグラフィーのモノマーの面積比より、また、メタクリル酸単位は電位差自動滴定装置で滴定し、各モノマー単位組成を算出した。
（３）メルトフローレート（ＭＦＲ）
ＪＩＳ Ｋ‐７２１０に準拠して２００℃、5ｋｇ荷重で行なった。
（４）ビカット軟化温度（ＶＳＴ）
ＪＩＳ Ｋ‐７２０６に準拠して行なった。
（５）吸水率
ＪＩＳ Ｋ−７２０９に準拠して測定した。
The physical properties of the copolymer resin used in the light diffusion plate resin composition were measured by the following method.
(1) Molecular weight Gel permeation chromatography was used to measure the polystyrene-reduced weight average molecular weight.
(2) Each unit composition in the copolymer The methyl methacrylate unit and styrene unit composition of the copolymer is determined from the area ratio of the monomer of pyrolysis gas chromatography, and the methacrylic acid unit is titrated with a potentiometric automatic titrator. Each monomer unit composition was calculated.
(3) Melt flow rate (MFR)
According to JIS K-7210, it was performed at 200 ° C. and 5 kg load.
(4) Vicat softening temperature (VST)
This was performed in accordance with JIS K-7206.
(5) Water absorption Measured according to JIS K-7209.
光拡散板の物性評価は、以下の方法により行なった。
（１）全光線透過率
ＪＩＳ Ｋ７１０５のＢ法に準拠して行なった。
（２）光拡散性
２ｃｍ間隔に冷陰極管４本を並べ、１０ｍｍ上に光拡散板サンプルを平行に固定し、目視により、光源である冷陰極管が透けていないものを○、透けているものを×で示した。
（３）輝度ムラ
２ｃｍ間隔に冷陰極管４本を並べ、１０ｍｍ上に光拡散板サンプルを平行に固定し、目視により、画面上で輝度が均一であるものは○、輝度ムラがあるものは×で示した。
（４）耐光性
メタルハライドランプを光源とした促進耐光性試験機を使用しフィルター：KF-1(透過波長領域；２９５~７８０nm) 、運転モード：連続照射、UV照度：７５mW/cm2、BP温度：
８０℃ 、槽内湿度：５０%RH 、スプレー：無い 、試験時間：２４時間、サンプル厚みは２ｍｍシートを使用した。耐光試験後のサンプルを分光型測色計を使用し透過光のΔEで評価した。
The physical properties of the light diffusing plate were evaluated by the following methods.
(1) Total light transmittance It carried out based on B method of JISK7105.
(2) Light diffusivity Four cold cathode tubes are arranged at intervals of 2 cm, a light diffusing plate sample is fixed in parallel on 10 mm, and the cold cathode tube, which is a light source, is visually transparent when it is transparent. The thing was shown by x.
(3) Luminance unevenness 4 cold-cathode tubes are arranged at intervals of 2 cm, a light diffusion plate sample is fixed in parallel on 10 mm, and visually, the brightness is uniform on the screen, ○, the brightness unevenness is Indicated by ×.
(4) Light resistance Using an accelerated light resistance tester with a metal halide lamp as the light source, filter: KF-1 (transmission wavelength region; 295 to 780 nm), operation mode: continuous irradiation, UV illuminance: 75 mW / cm 2 , BP temperature :
80 ° C., humidity in tank: 50% RH, spray: none, test time: 24 hours, sample thickness was 2 mm. The sample after the light resistance test was evaluated by ΔE of transmitted light using a spectroscopic colorimeter.
また、実施例及び比較例中で使用する略号は次の意味を有する。
ＭＭＡ：メタクリル酸メチル
ＭＡＡ：メタクリル酸
Ｓｔ：スチレン
開始剤：パーカドックス１２‐ＥＢ２０
Moreover, the symbol used in an Example and a comparative example has the following meaning.
MMA: Methyl methacrylate MAA: Methacrylic acid St: Styrene Initiator: Parkardox 12-EB20
参考例１〜9
原料モノマー及び重合開始剤を表１のポリマー組成になるように仕込み、反応温度１２０℃、５時間滞留条件下で、一槽型完全混合反応器と脱揮槽を連結した設備を用いて連続塊状重合、脱揮、ペレット化し、目的とする透明な共重合樹脂を得た。該樹脂を７５ｔ成形機（三菱重工製）により、樹脂温度２４０℃にて射出成形を行い、縦５０×横７５ｍｍ×厚さ４ｍｍの吸水率測定用プレート、縦１０×横１０ｍｍ×厚さ４ｍｍのＶＳＴ測定用試験片を得た。得られた共重合樹脂の組成を表１に記載する。表１において、共重合樹脂組成は、ＭＭＡ単位／ＭＡＡ単位／Ｓｔ単位である。
Reference Examples 1-9
The raw material monomer and the polymerization initiator were charged so as to have the polymer composition shown in Table 1, and the reaction temperature was 120 ° C. and the residence condition was 5 hours. Polymerization, devolatilization, and pelletization were performed to obtain a desired transparent copolymer resin. The resin was injection-molded at a resin temperature of 240 ° C. with a 75 t molding machine (Mitsubishi Heavy Industries), and a water absorption measurement plate having a length of 50 × width of 75 mm × thickness of 4 mm, length of 10 × width of 10 mm × thickness of 4 mm. A test piece for VST measurement was obtained. The composition of the obtained copolymer resin is shown in Table 1. In Table 1, the copolymer resin composition is MMA unit / MAA unit / St unit.
得られた樹脂の分子量並びに各種の物性について測定した結果を表１に示す。 Table 1 shows the measurement results of the molecular weight and various physical properties of the obtained resin.
実施例１〜３及び比較例１〜３
参考例にて作製した共重合樹脂と表２に示す拡散剤を二軸押出機にて混練、ペレット化した樹脂組成物とした。この樹脂組成物を、樹脂温度２２０℃にて押出成形して厚さ２ｍｍの光拡散板を作製した。得られた光拡散板の全光線透過率、光拡散性、輝度ムラについて表２に記載する。ここで使用したシロキサン系重合体粒子は平均粒径２μｍ、アクリル系重合体粒子は平均粒径１０μｍ、炭酸カルシウムは平均粒径１．８μｍである。なお、表２において、シロキサン系重合体粒子、アクリル系重合体粒子及び炭酸カルシウムは、それぞれシロキサン系、アクリル系及び炭カルと略記する。
Examples 1-3 and Comparative Examples 1-3
A copolymer composition prepared in Reference Example and a diffusing agent shown in Table 2 were kneaded and pelletized with a twin screw extruder. This resin composition was extruded at a resin temperature of 220 ° C. to produce a light diffusion plate having a thickness of 2 mm. Table 2 shows the total light transmittance, light diffusibility, and luminance unevenness of the obtained light diffusing plate. The siloxane polymer particles used here have an average particle size of 2 μm, the acrylic polymer particles have an average particle size of 10 μm, and the calcium carbonate has an average particle size of 1.8 μm. In Table 2, siloxane polymer particles, acrylic polymer particles, and calcium carbonate are abbreviated as siloxane, acrylic, and charcoal, respectively.
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| KR1020080117848A KR20090054913A (en) | 2007-11-27 | 2008-11-26 | Resin composition for light diffusing plate and light diffusing plate |
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| JP6039907B2 (en) * | 2012-02-17 | 2016-12-07 | 東洋スチレン株式会社 | Styrenic resin plate-shaped molded article and light guide plate |
| CN105419207B (en) * | 2014-09-12 | 2020-01-17 | 住友化学株式会社 | Thermoplastic resin film |
| US10633528B2 (en) | 2014-12-19 | 2020-04-28 | Ineos Styrolution Group Gmbh | Light diffusing styrene copolymer compositions |
| CN106398014A (en) * | 2016-11-09 | 2017-02-15 | 安徽新胜塑料科技有限公司 | Method for processing acrylic diffusion plates |
| FR3087776B1 (en) * | 2018-10-26 | 2021-07-30 | Arkema France | POLYMER COMPOSITION COMPRISING PARTICLES AND A COLORANT, ITS PREPARATION PROCESS AND ITS USE |
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