JP5629064B2 - White film for reflector - Google Patents
White film for reflector Download PDFInfo
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- JP5629064B2 JP5629064B2 JP2009155283A JP2009155283A JP5629064B2 JP 5629064 B2 JP5629064 B2 JP 5629064B2 JP 2009155283 A JP2009155283 A JP 2009155283A JP 2009155283 A JP2009155283 A JP 2009155283A JP 5629064 B2 JP5629064 B2 JP 5629064B2
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- reflector
- impact test
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- 229920000728 polyester Polymers 0.000 claims description 24
- 238000004080 punching Methods 0.000 claims description 17
- 238000009863 impact test Methods 0.000 claims description 13
- 239000011800 void material Substances 0.000 claims description 13
- 125000003118 aryl group Chemical group 0.000 claims description 9
- 229920006267 polyester film Polymers 0.000 claims description 7
- 238000005520 cutting process Methods 0.000 claims description 6
- 238000010998 test method Methods 0.000 claims description 4
- 238000002310 reflectometry Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 description 33
- 239000010954 inorganic particle Substances 0.000 description 17
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 16
- 239000004973 liquid crystal related substance Substances 0.000 description 9
- 229920005992 thermoplastic resin Polymers 0.000 description 9
- 229920001577 copolymer Polymers 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- -1 polyethylene terephthalate Polymers 0.000 description 7
- 229920000139 polyethylene terephthalate Polymers 0.000 description 7
- 239000005020 polyethylene terephthalate Substances 0.000 description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- WOZVHXUHUFLZGK-UHFFFAOYSA-N dimethyl terephthalate Chemical compound COC(=O)C1=CC=C(C(=O)OC)C=C1 WOZVHXUHUFLZGK-UHFFFAOYSA-N 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 150000002009 diols Chemical class 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000004594 Masterbatch (MB) Substances 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 description 2
- 239000003086 colorant Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- VNGOYPQMJFJDLV-UHFFFAOYSA-N dimethyl benzene-1,3-dicarboxylate Chemical compound COC(=O)C1=CC=CC(C(=O)OC)=C1 VNGOYPQMJFJDLV-UHFFFAOYSA-N 0.000 description 2
- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 description 2
- 238000009998 heat setting Methods 0.000 description 2
- 229920001519 homopolymer Polymers 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004745 nonwoven fabric Substances 0.000 description 2
- 239000011146 organic particle Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- NEQFBGHQPUXOFH-UHFFFAOYSA-N 4-(4-carboxyphenyl)benzoic acid Chemical compound C1=CC(C(=O)O)=CC=C1C1=CC=C(C(O)=O)C=C1 NEQFBGHQPUXOFH-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- YIMQCDZDWXUDCA-UHFFFAOYSA-N [4-(hydroxymethyl)cyclohexyl]methanol Chemical compound OCC1CCC(CO)CC1 YIMQCDZDWXUDCA-UHFFFAOYSA-N 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 229940119177 germanium dioxide Drugs 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- XXMIOPMDWAUFGU-UHFFFAOYSA-N hexane-1,6-diol Chemical compound OCCCCCCO XXMIOPMDWAUFGU-UHFFFAOYSA-N 0.000 description 1
- 239000004611 light stabiliser Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229940071125 manganese acetate Drugs 0.000 description 1
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- RXOHFPCZGPKIRD-UHFFFAOYSA-N naphthalene-2,6-dicarboxylic acid Chemical compound C1=C(C(O)=O)C=CC2=CC(C(=O)O)=CC=C21 RXOHFPCZGPKIRD-UHFFFAOYSA-N 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 238000005809 transesterification reaction Methods 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- WVLBCYQITXONBZ-UHFFFAOYSA-N trimethyl phosphate Chemical compound COP(=O)(OC)OC WVLBCYQITXONBZ-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Liquid Crystal (AREA)
- Laminated Bodies (AREA)
- Optical Elements Other Than Lenses (AREA)
Description
本発明は、液晶表示装置のバックライトユニットの反射板として用いられる、反射板用白色フィルムに関する。 The present invention relates to a white film for a reflector used as a reflector of a backlight unit of a liquid crystal display device.
液晶表示装置のバックライトユニットには、光源からの光が画面の背面へ逃げるのを防ぐために、背面に反射板が設置されている。この反射板には、薄くかつ高い反射率を備えることが要求される。 In the backlight unit of the liquid crystal display device, a reflector is installed on the back surface in order to prevent light from the light source from escaping to the back surface of the screen. This reflector is required to be thin and have a high reflectance.
液晶表示装置用のバックライトユニットに用いる反射フィルムとして、フィルムの内部に微細な気泡を含有する白色ポリエステルフィルムが知られており、液晶表示装置用反射フィルムとして広く利用されている。 As a reflective film used in a backlight unit for a liquid crystal display device, a white polyester film containing fine bubbles inside the film is known and widely used as a reflective film for a liquid crystal display device.
反射板用白色フィルムは、所定の形状に加工されてバックライトユニットに組み込まれる。この加工のために反射板用白色フィルムを所定の形状に裁断する工程があるが、この工程での裁断速度は、バックライトユニットの大量生産化が進むに伴い速くなっている。従来の反射フィルムで高輝度を得られるものは、断裁時にフィルムの端面にカエリやヒゲ状物が発生し易い。このカエリやヒゲ状物は生産性を低下させる原因となる。なお、ヒゲ状物は、裁断による切断面に発生する細い突起部であり、カエリは、裁断による切断面付近に発生する部分的に盛り上がった部分である。 The white film for a reflector is processed into a predetermined shape and incorporated in the backlight unit. For this processing, there is a step of cutting the reflector white film into a predetermined shape, and the cutting speed in this step increases as mass production of backlight units proceeds. A conventional reflective film capable of obtaining high brightness tends to cause burrs and whiskers on the end face of the film during cutting. These burrs and whiskers can reduce productivity. The whiskers are thin protrusions generated on the cut surface by cutting, and the burrs are partially raised portions generated near the cut surface by cutting.
本発明は、液晶表示装置のバックライトユニットに反射板として用いたときに高い輝度を得ることができ、打ち抜き加工の際にカエリやヒゲ状物が発生し難い、打ち抜き性に優れる液晶表示装置のバックライトユニットに用いられる反射板用白色フィルムを提供することを目的とする。 The present invention is a liquid crystal display device that can obtain high luminance when used as a reflector in a backlight unit of a liquid crystal display device, is less likely to cause burrs and whiskers during punching, and has excellent punchability. It aims at providing the white film for reflectors used for a backlight unit.
すなわち本発明は、芳香族ポリエステル中にボイドを形成しボイド体積率が５５〜８０％である光反射層、およびその少なくとも一方の面に設けられた二軸延伸芳香族ポリステルフィルムの支持層からなり、光反射層の厚みの合計と支持層の厚みの合計との比が９２：８〜９８：２であり、フィルムの反射率が９８.０％以上であり、かつ断裁時にカエリ及びヒゲ状物を発生し難くするために下記試験方法により求められる落下衝撃試験による打ち抜きエネルギーが０．１０〜０．３０Ｊとなるようにし、フィルム厚みが１５０〜２５０μｍであることを特徴とする、反射板用白色芳香族ポリエステルフィルムである。
［落下衝撃試験による打ち抜きエネルギーの試験方法］
デュポン式衝撃試験（ＪＩＳ Ｋ５６００−５−３、ＩＳＯ６２７２）に基づき、２５℃、５０％ＲＨ環境下で調整されたサンプルフィルム（３０ｍｍ×３０ｍｍ）を受台の上にセットし、撃芯（直径４ｍｍの円柱状、材質ＳＵＳ）をサンプルフィルムの上に設置し、おもり（荷重３００ｇｆ）を撃芯の上に落下させ、サンプルフィルム５０枚の半数に割れが生じる落下高さを求め、かかる落下高さに荷重を掛けて、落下衝撃試験による打ち抜きエネルギー（Ｊ）とした。
That is, the present invention comprises a light reflecting layer in which voids are formed in an aromatic polyester and the void volume ratio is 55 to 80%, and a biaxially stretched aromatic polyester film support layer provided on at least one surface thereof. The ratio of the total thickness of the light reflecting layer to the total thickness of the support layer is 92: 8 to 98: 2, the film reflectance is 98.0% or more, and burrs and whiskers when cut White for a reflector, wherein the punching energy by a drop impact test required by the following test method is 0.10 to 0.30 J and the film thickness is 150 to 250 μm. An aromatic polyester film.
[Test method of punching energy by drop impact test]
Based on the DuPont impact test (JIS K5600-5-3, ISO 6272), a sample film (30 mm × 30 mm) adjusted in an environment of 25 ° C. and 50% RH is set on a cradle, and a strike core (diameter 4 mm) Is placed on the sample film, the weight (load 300 gf) is dropped on the strike core, and the drop height at which half of the 50 sample films are cracked is determined. A load was applied to the punching energy (J) in the drop impact test.
本発明によれば、液晶表示装置のバックライトユニットに反射板として用いたときに高い輝度を得ることができ、打ち抜き加工の際にカエリやヒゲ状物が発生し難い、打ち抜き性に優れる、反射板用白色フィルムを提供することができる。 According to the present invention, high brightness can be obtained when used as a reflector in a backlight unit of a liquid crystal display device, and burrs and whiskers are not easily generated during punching, and the punching property is excellent. A white film for plates can be provided.
以下、本発明を詳細に説明する。
本発明の反射板用白色フィルムは、光反射層およびその少なくとも一方の面に設けられた二軸延伸ポリステルフィルムの支持層からなる。
Hereinafter, the present invention will be described in detail.
The white film for a reflector of the present invention comprises a light reflecting layer and a biaxially stretched polyester film support layer provided on at least one surface thereof.
［光反射層］
本発明における光反射層は、白色の着色剤を熱可塑性樹脂中に含有させることによって白色を呈するようにした層またはボイド形成物質を熱可塑性樹脂中に含有させて延伸することにより熱可塑性樹脂とボイド形成物質との界面にボイドを形成することで白色を呈するにようした層である。
本発明の光反射層のボイド体積率は５５〜８０％、さらに好ましくは６０〜７５％、特に好ましくは６２〜７０％である。ボイド体積率が５５％未満であると高い反射率を得ることができず、打ち抜き加工性も劣るものとなる。他方、ボイド体積率が８０％を超えると製膜が非常に困難になる。
[Light reflection layer]
The light-reflecting layer in the present invention comprises a thermoplastic resin by stretching a white-colored layer or void-forming substance contained in the thermoplastic resin by containing the white colorant in the thermoplastic resin. It is a layer that exhibits white by forming a void at the interface with the void-forming substance.
The void volume ratio of the light reflection layer of the present invention is 55 to 80%, more preferably 60 to 75%, and particularly preferably 62 to 70%. When the void volume ratio is less than 55%, a high reflectance cannot be obtained, and the punching workability is also inferior. On the other hand, when the void volume ratio exceeds 80%, film formation becomes very difficult.
［ポリエステル］
光反射層の熱可塑性樹脂としては、好ましくは熱可塑性のポリエステルを用いる。熱可塑性のポリエステルを用いる場合、ポリエステルとしては、ジカルボン酸成分とジオール成分とからなるポリエステルを用いる。このジカルボン酸としては、例えばテレフタル酸、イソフタル酸、２，６―ナフタレンジカルボン酸、４，４’―ジフェニルジカルボン酸、アジピン酸、セバシン酸を挙げることができる。ジオールとしては、例えばエチレングリコール、１，４―ブタンジオール、１，４―シクロヘキサンジメタノール、１，６―ヘキサンジオールを挙げることができる。これらのポリエステルのなかでも芳香族ポリエステルが好ましく、特に、ポリエチレンテレフタレートが好ましい。ポリエチレンテレフタレートは、ホモポリマーであってもよいが、共重合ポリマーが好ましい。共重合ポリマーである場合、共重合成分の割合は、全ジカルボン酸成分を基準として例えば１〜２０モル％、好ましくは２〜１５モル％、さらに好ましくは３〜１３モル％である。共重合成分の割合をこの範囲とすることによって、光反射層についても優れた製膜性を得ることができ、熱寸法安定性に優れたフィルムを得ることできる。
[polyester]
As the thermoplastic resin for the light reflecting layer, thermoplastic polyester is preferably used. When a thermoplastic polyester is used, a polyester composed of a dicarboxylic acid component and a diol component is used as the polyester. Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, adipic acid, and sebacic acid. Examples of the diol include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and 1,6-hexanediol. Among these polyesters, aromatic polyesters are preferable, and polyethylene terephthalate is particularly preferable. Polyethylene terephthalate may be a homopolymer, but is preferably a copolymer. In the case of a copolymer, the proportion of the copolymer component is, for example, 1 to 20 mol%, preferably 2 to 15 mol%, more preferably 3 to 13 mol%, based on the total dicarboxylic acid component. By setting the proportion of the copolymer component within this range, it is possible to obtain excellent film-forming properties for the light reflecting layer, and it is possible to obtain a film having excellent thermal dimensional stability.
［白色無機粒子］
光反射層の白色の着色剤としては、白色無機粒子を用いる。ボイド形成物質としては、白色無機粒子、有機粒子または非相溶樹脂を用いる。
白色無機粒子としては、例えば、硫酸バリウム粒子、二酸化チタン粒子、二酸化珪素粒子、炭酸カルシウム粒子を用いることができる。白色無機粒子の平均粒径は、好ましくは０．１〜３．０μｍ、さらに好ましくは０．２〜２．５μｍ、特に好ましくは０．３〜２．０μｍである。この範囲の平均粒径の白色無機粒子を用いることで、熱可塑性樹脂中に適度に分散させることができ、白色無機粒子の凝集が起こりずらく、表面に粗大突起のない光反射層を得ることができる。同時に、光反射層の表面が粗れすぎず、適切な範囲の光沢度にすることができる。白色無機粒子として最も好ましいものは、平均粒子径が０．１〜３．０μｍの硫酸バリウム粒子である。
[White inorganic particles]
White inorganic particles are used as the white colorant for the light reflecting layer. As the void forming substance, white inorganic particles, organic particles, or incompatible resins are used.
As the white inorganic particles, for example, barium sulfate particles, titanium dioxide particles, silicon dioxide particles, and calcium carbonate particles can be used. The average particle diameter of the white inorganic particles is preferably 0.1 to 3.0 μm, more preferably 0.2 to 2.5 μm, and particularly preferably 0.3 to 2.0 μm. By using white inorganic particles having an average particle diameter in this range, it is possible to appropriately disperse the particles in the thermoplastic resin, and to obtain a light reflecting layer that hardly aggregates the white inorganic particles and has no coarse protrusions on the surface. Can do. At the same time, the surface of the light reflecting layer is not too rough, and the glossiness in an appropriate range can be obtained. The most preferable white inorganic particles are barium sulfate particles having an average particle size of 0.1 to 3.0 μm.
白色無機粒子の平均粒径は、ｄ５０（メジアン径）を採用するが、粒子径の小さいものから１０％のｄ１０、小さいものから９０％のｄ９０で表した際、粒度分布のｄ９０／ｄ１０が、好ましくは１〜５００、さらに好ましくは１〜３００、さらに好ましくは１〜１００、特に好ましくは１〜５０である。５００を超える粒度分布である場合、フィルターに粗大粒子が詰まったり、微小粒子が再凝集する場合があり好ましくない。
白色無機粒子は、どのような粒子形状でもあってもよく、例えば、板状、球状であってもよい。白色無機粒子は、分散性を向上させるために表面処理を行ってあってもよい。
As the average particle diameter of the white inorganic particles, d50 (median diameter) is adopted. When expressed from 10% d10 from the smallest particle diameter to d90 from 90%, d90 / d10 of the particle size distribution is Preferably it is 1-500, More preferably, it is 1-300, More preferably, it is 1-100, Most preferably, it is 1-50. When the particle size distribution exceeds 500, coarse particles may be clogged in the filter, or fine particles may reaggregate, which is not preferable.
The white inorganic particles may have any particle shape, for example, a plate shape or a spherical shape. The white inorganic particles may be subjected to a surface treatment in order to improve dispersibility.
ボイド形成物質として有機粒子を用いる場合、例えば、架橋ポリスチレン粒子、アクリル粒子を用いることができる。
ボイド形成物質として非相溶樹脂を用いる場合、光反射層の熱可塑性樹脂に非相溶な樹脂を用いる。非相溶樹脂として、例えば、ポリオレフィン、ポリスチレンを用いることができる。
When organic particles are used as the void forming substance, for example, crosslinked polystyrene particles and acrylic particles can be used.
When an incompatible resin is used as the void-forming substance, an incompatible resin is used for the thermoplastic resin of the light reflecting layer. As the incompatible resin, for example, polyolefin and polystyrene can be used.
光反射層が白色無機粒子および熱可塑性樹脂からなる組成物から構成される場合、白色無機粒子は好ましくは５０〜６０重量％を占め、熱可塑性樹脂は好ましくは５０〜４０重量％を占める。この範囲の組成であると良好な反射率と打ち抜き加工性、安定したフィルム製膜が期待できる。
光反射層の組成物は、必要に応じて、白色無機粒子および熱可塑性樹脂以外の成分を含有してもよい。そのような成分として、例えば、紫外線吸収剤、酸化防止剤、光安定剤、難燃剤を挙げることができる。
When the light reflecting layer is composed of a composition composed of white inorganic particles and a thermoplastic resin, the white inorganic particles preferably account for 50 to 60% by weight, and the thermoplastic resin preferably accounts for 50 to 40% by weight. When the composition is in this range, good reflectance, punching workability, and stable film formation can be expected.
The composition of the light reflection layer may contain components other than the white inorganic particles and the thermoplastic resin, if necessary. Examples of such components include ultraviolet absorbers, antioxidants, light stabilizers, and flame retardants.
［支持層］
支持層は二軸延伸ポリエステルフィルムからなる。ポリエステルとしては、芳香族ジカルボン酸成分とジオール成分とからなる芳香族ポリエステルが好ましく、特に、ポリエチレンテレフタレートが好ましい。ポリエチレンテレフタレートは、ホモポリマーであってもよいが、共重合ポリマーが好ましい。共重合ポリマーである場合、共重合成分の割合は、全ジカルボン酸成分を基準として例えば１〜２０モル％、好ましくは２〜１５モル％、さらに好ましくは３〜１３モル％である。共重合成分の割合をこの範囲とすることによって、光反射層についても優れた製膜性を得ることができ、熱寸法安定性に優れたフィルムを得ることできる。
[Support layer]
The support layer is made of a biaxially stretched polyester film. As the polyester, an aromatic polyester composed of an aromatic dicarboxylic acid component and a diol component is preferable, and polyethylene terephthalate is particularly preferable. Polyethylene terephthalate may be a homopolymer, but is preferably a copolymer. In the case of a copolymer, the proportion of the copolymer component is, for example, 1 to 20 mol%, preferably 2 to 15 mol%, more preferably 3 to 13 mol%, based on the total dicarboxylic acid component. By setting the proportion of the copolymer component within this range, it is possible to obtain excellent film-forming properties for the light reflecting layer, and it is possible to obtain a film having excellent thermal dimensional stability.
［層構成］
本発明の反射板用白色フィルムは、共押出し法により製造されたものであることが好ましい。すなわち、光反射層と支持層とは、共押出し法により積層されていることが好ましい。本発明の反射板用白色フィルムは、単一もしくは複数の光反射層を含み、単一もしくは複数の支持層を含む。光反射層の厚みの合計と支持層の厚みの合計との比は８５：１５〜９８：２、好ましくは９５：５〜９８：２である。反射層の厚みの合計がフィルムの総厚みに占める割合が８５未満であると高い反射率を得ることが難しくなり、他方、９８を超えるとフィルムの破断が多くなり、安定して製膜することが難しくなる。
[Layer structure]
The white film for a reflector of the present invention is preferably manufactured by a coextrusion method. That is, the light reflecting layer and the support layer are preferably laminated by a coextrusion method. The white film for a reflector of the present invention includes a single or a plurality of light reflection layers, and includes a single or a plurality of support layers. The ratio of the total thickness of the light reflecting layer to the total thickness of the support layer is 85:15 to 98: 2, preferably 95: 5 to 98: 2. When the ratio of the total thickness of the reflective layer to the total thickness of the film is less than 85, it is difficult to obtain a high reflectivity. On the other hand, when the ratio exceeds 98, the film is frequently broken and the film is stably formed. Becomes difficult.
本発明の反射板用白色フィルムは、光反射層の少なくとも一方の面に支持層が設けられた構成であり、具体的には、例えば、光反射層／支持層の２層構成、支持層／光反射層／支持層の３層構成、光反射層／支持層／光反射層の３層構成、支持層／光反射層／支持層／光反射層の４層構成、支持層／光反射層／支持層／光反射層／支持層の５層構成をとることができる。このうち製膜安定性や製造コストの観点から、支持層／光反射層／支持層の３層構成が好ましい。 The white film for a reflector of the present invention has a configuration in which a support layer is provided on at least one surface of the light reflection layer. Specifically, for example, a two-layer configuration of a light reflection layer / support layer, a support layer / Three-layer configuration of light reflection layer / support layer, three-layer configuration of light reflection layer / support layer / light reflection layer, four-layer configuration of support layer / light reflection layer / support layer / light reflection layer, support layer / light reflection layer A five-layer structure of / support layer / light reflecting layer / support layer can be taken. Of these, a three-layer structure of support layer / light reflection layer / support layer is preferable from the viewpoint of film formation stability and production cost.
本発明の反射板用白色フィルムの総厚みは１５０〜２５０μｍ、好ましくは１７０〜２３０μｍである。この範囲の総厚みであるでことによって良好なハンドリング性および生産性を得ることができる。１５０μｍ未満であると反射率が不足する。他方、２５０μｍを超えると、十分な反射率は得られるものの、打ち抜き性が劣る。 The total thickness of the white film for a reflector of the present invention is 150 to 250 μm, preferably 170 to 230 μm. When the total thickness is within this range, good handling properties and productivity can be obtained. If it is less than 150 μm, the reflectance is insufficient. On the other hand, if it exceeds 250 μm, sufficient reflectivity can be obtained, but punchability is poor.
［落下衝撃試験、光反射率］
本発明の反射板用白色フィルムは、落下衝撃試験による打ち抜きエネルギーが０．１０〜０．３０Jであることが必要である。０．１０Ｊ未満であるとフィルム自体が割れ易く、０．３０Ｊを超えるとヒゲ状物やカエリが発生する。
本発明の反射板用白色フィルムの光反射率は、波長５５０ｎｍにおける反射率として、好ましくは９８．０％以上、さらに好ましくは９８．５％以上、特に好ましくは９９．０％以上である。反射率が９８．０％以上であることによってバックライトユニットに用いたときに高い輝度を得ることができる。
[Drop impact test, light reflectance]
The white film for a reflector of the present invention is required to have a punching energy by a drop impact test of 0.10 to 0.30 J. If it is less than 0.10 J, the film itself is easily broken, and if it exceeds 0.30 J, beard-like materials and burrs are generated.
The light reflectance of the white film for a reflector of the present invention is preferably 98.0% or more, more preferably 98.5% or more, and particularly preferably 99.0% or more as the reflectance at a wavelength of 550 nm. When the reflectance is 98.0% or more, high luminance can be obtained when used in a backlight unit.
［製造方法］
以下、本発明の反射板用白色フィルムを製造する方法の一例を説明する。以下、ポリマーのガラス転移温度をＴｇ、融点をＴｍということがある。
反射板用白色フィルムの製造に用いるポリエステルは、線径１５μｍ以下のステンレス鋼細線よりなる平均目開き１０〜１００μｍの不織布型フィルターを用いて濾過を行うことが好ましい。この濾過を行うことで、通常は凝集して粗大凝集粒子となりやすい粒子の凝集を抑え、粗大異物の少ない白色フィルムを得ることができる。なお、不織布の平均目開きは、好ましくは２０〜５０μｍ、さらに好ましくは１５〜４０μｍである。濾過したポリエステルの組成物は、溶融した状態でフィードブロックを用いた同時多層押出法により、ダイから多層状態で押出し、未延伸積層シートを製造する。
[Production method]
Hereinafter, an example of the method of manufacturing the white film for reflectors of this invention is demonstrated. Hereinafter, the glass transition temperature of the polymer may be referred to as Tg and the melting point as Tm.
The polyester used for the production of the white film for the reflector is preferably filtered using a nonwoven fabric type filter having an average opening of 10 to 100 μm made of a stainless steel fine wire having a wire diameter of 15 μm or less. By performing this filtration, it is possible to suppress agglomeration of particles that normally tend to aggregate into coarse aggregated particles, and to obtain a white film with few coarse foreign matters. In addition, the average opening of a nonwoven fabric becomes like this. Preferably it is 20-50 micrometers, More preferably, it is 15-40 micrometers. The filtered polyester composition is extruded in a multilayer state from a die by a simultaneous multilayer extrusion method using a feed block in a molten state to produce an unstretched laminated sheet.
ダイより押出された未延伸積層シートは、キャスティングドラムで冷却固化され、未延伸積層フィルムとなる。この未延伸積層フィルムをロール加熱、赤外線加熱等で加熱し、縦方向に延伸して縦延伸積層フィルムを得る。この延伸は２個以上のロールの周速差を利用して行うのが好ましい。延伸は、ポリエステルのＴｇ以上の温度で行うことが好ましい。延伸倍率は、縦方向、縦方向と直交する方向（以降、横方向と呼ぶ）ともに、好ましくは２．５〜４．３倍、さらに好ましくは２．７〜４．２倍である。２．５倍未満とするとフィルムの厚み斑が悪くなり良好なフィルムが得られず、４．３倍を超えると製膜中に破断が発生し易くなり好ましくない。 The unstretched laminated sheet extruded from the die is cooled and solidified by a casting drum to form an unstretched laminated film. This unstretched laminated film is heated by roll heating, infrared heating or the like, and stretched in the longitudinal direction to obtain a longitudinally stretched laminated film. This stretching is preferably performed by utilizing the difference in peripheral speed between two or more rolls. The stretching is preferably performed at a temperature equal to or higher than the Tg of the polyester. The draw ratio is preferably 2.5 to 4.3 times, more preferably 2.7 to 4.2 times in both the longitudinal direction and the direction orthogonal to the longitudinal direction (hereinafter referred to as the transverse direction). If it is less than 2.5 times, uneven thickness of the film is deteriorated and a good film cannot be obtained, and if it exceeds 4.3 times, breakage tends to occur during film formation, which is not preferable.
縦延伸後の積層フィルムは、続いて、横延伸、熱固定、熱弛緩の処理を順次施して積層二軸配向フィルムとするが、これらの処理は、フィルムを走行させながら行う。横延伸の予熱処理はポリエステルのＴｇより高い温度から始める。横延伸過程での昇温は連続的でも段階的（逐次的）でもよいが通常逐次的に昇温する。例えばテンターの横延伸ゾーンをフィルム走行方向に沿って複数に分け、ゾーン毎に所定温度の加熱媒体を流すことで昇温する。横延伸後のフィルムは、両端を把持したまま（Ｔｍ−２０℃）〜（Ｔｍ−１００℃）で定幅または１０％以下の幅減少下で熱処理して熱収縮率を低下させるのがよい。熱処理温度が（Ｔｍ−２０℃）より高いとフィルムの平面性が悪くなり、厚み斑が大きくなり好ましくない。（Ｔｍ−１００℃）より低いと熱収縮率が大きくなることがあり好ましくない。また、熱収縮量を調整するために、把持しているフィルムの両端を切り落し、フィルム縦方向の引き取り速度を調整し、縦方向に弛緩させることができる。弛緩させる手段としてはテンター出側のロール群の速度を調整する。弛緩させる割合として、テンターのフィルムライン速度に対してロール群の速度ダウンを行い、好ましくは０．１〜２．５％、さらに好ましくは０．２〜２．３％、特に好ましくは０．３〜２．０％の速度ダウンを実施してフィルムを弛緩（この値を「弛緩率」という）して、弛緩率をコントロールすることによって縦方向の熱収縮率を調整する。また、フィルム横方向は両端を切り落すまでの過程で幅減少させて、所望の熱収縮率を得ることができる。 The laminated film after longitudinal stretching is subsequently subjected to lateral stretching, heat setting, and thermal relaxation to form a laminated biaxially oriented film. These treatments are performed while the film is running. The pre-heat treatment for transverse stretching starts from a temperature higher than the Tg of the polyester. Although the temperature rise in the transverse stretching process may be continuous or stepwise (sequential), the temperature is usually raised sequentially. For example, the transverse stretching zone of the tenter is divided into a plurality along the film running direction, and the temperature is raised by flowing a heating medium having a predetermined temperature for each zone. The film after transverse stretching is preferably heat-treated with a constant width or a decrease in width of 10% or less while holding both ends (Tm−20 ° C.) to (Tm−100 ° C.) to reduce the thermal shrinkage rate. When the heat treatment temperature is higher than (Tm−20 ° C.), the flatness of the film is deteriorated and the thickness unevenness is increased, which is not preferable. If it is lower than (Tm-100 ° C.), the heat shrinkage rate may increase, which is not preferable. Further, in order to adjust the heat shrinkage, both ends of the film being held can be cut off, the take-up speed in the film vertical direction can be adjusted, and the film can be relaxed in the vertical direction. As a means for relaxing, the speed of the roll group on the tenter exit side is adjusted. As the rate of relaxation, the speed of the roll group is reduced with respect to the film line speed of the tenter, preferably 0.1 to 2.5%, more preferably 0.2 to 2.3%, particularly preferably 0.3. The film is relaxed by performing a speed reduction of ˜2.0% (this value is referred to as “relaxation rate”), and the longitudinal heat shrinkage rate is adjusted by controlling the relaxation rate. Further, the width of the film in the horizontal direction can be reduced in the process until both ends are cut off, and a desired heat shrinkage rate can be obtained.
また、本発明の積層フィルムは逐次二軸延伸法以外にも同時二軸延伸法を用いて製膜することができる。延伸倍率は、縦方向、横方向ともに例えば２．７〜４．３倍、好ましくは２．８〜４．２倍である。 The laminated film of the present invention can be formed using a simultaneous biaxial stretching method in addition to the sequential biaxial stretching method. The draw ratio is, for example, 2.7 to 4.3 times, preferably 2.8 to 4.2 times in both the longitudinal direction and the transverse direction.
以下、実施例により本発明を詳述する。なお、各特性値は以下の方法で測定した。
なお、ＰＥＴはポリエチレンテレフタレート、ＩＰＡはイソフタル酸を意味する。
Hereinafter, the present invention will be described in detail by way of examples. Each characteristic value was measured by the following method.
Incidentally, PET means polyethylene terephthalate, and IPA means isophthalic acid.
（１）反射率
分光光度計（島津製作所製ＵＶ−３１０１ＰＣ）に積分球を取り付け、ＢａＳＯ４白板を１００％としたときのサンプルフィルムの反射率を波長５５０ｎｍで測定した。
(1) Reflectance An integrating sphere was attached to a spectrophotometer (Shimadzu UV-3101PC), and the reflectance of the sample film was measured at a wavelength of 550 nm when the BaSO 4 white plate was taken as 100%.
（２）輝度
液晶表示装置に反射板として用いたときの表示装置の輝度を評価した。ソニー（株）製３２インチテレビ（ブラビアＫＤＬ−３２Ｖ２５００）のバックライトの反射フィルムを取り外し、かわりに評価対象のサンプルフィルムを設置し、輝度計（大塚電子製Ｍｏｄｅｌ ＭＣ−９４０）を用いて、バックライトの中心を真正面より測定距離５００ｍｍで輝度を測定した。
(2) Luminance The luminance of the display device when used as a reflector in a liquid crystal display device was evaluated. Remove the reflective film from the backlight of Sony Corporation's 32-inch TV (BRAVIA KDL-32V2500), install the sample film to be evaluated instead, and use the luminance meter (Model MC-940, manufactured by Otsuka Electronics) The luminance was measured at a measuring distance of 500 mm from the front of the light.
（３）無機粒子の平均粒径
粒度分布計（堀場製作所製ＬＡ−９５０）にて、粒子の粒度分布を求め、ｄ５０での粒子径を平均粒径とした。
(3) Average particle size of inorganic particles The particle size distribution of the particles was obtained with a particle size distribution meter (LA-950, manufactured by Horiba Ltd.), and the particle size at d50 was defined as the average particle size.
（４）落下衝撃試験による打ち抜きエネルギー
デュポン式衝撃試験（ＪＩＳ Ｋ５６００−５−３、ＩＳＯ６２７２）に基づき実施した。２５℃、５０％ＲＨ環境下で調整されたサンプルフィルム（３０ｍｍ×３０ｍｍ）を受台の上にセットし、撃芯（直径４ｍｍの円柱状、材質ＳＵＳ）をサンプルフィルムの上に設置した。おもり（荷重３００ｇ）を適当な位置より撃芯の上に落下させ、撃芯の下のサンプルフィルムに割れが生じたかどうかを観察した。割れの有無の判定では、サンプルフィルムの伸びにより円状に抜けきれたものは割れがあるとは判定せず、サンプルフィルムにヒビ割れの生じたもののみを割れがあると判定した。
サンプルフィルムの割れが発生するまで落下高さを１ｃｍ刻みで高くして、サンプルフィルムに割れが生じるまで予備テストを行った。サンプルフィルムに割れが発生した場合には落下高さを１ｃｍ低くし、割れが発生しない場合には落下高さを１ｃｍ高くすることを繰り返した。サンプルフィルム５０枚についてこのテスト行い、サンプルフィルムの半数に割れが生じる落下高さを求めた。落下高さに荷重を掛けて、落下衝撃試験による打ち抜きエネルギー（Ｊ）とした。
(4) Punching energy by drop impact test It was carried out based on the DuPont impact test (JIS K5600-5-3, ISO6272). A sample film (30 mm × 30 mm) adjusted in an environment of 25 ° C. and 50% RH was set on a cradle, and an impact core (cylindrical shape with a diameter of 4 mm, material SUS) was placed on the sample film. A weight (a load of 300 g) was dropped on the strike core from an appropriate position, and it was observed whether or not the sample film under the strike core was cracked. In the determination of the presence or absence of cracks, it was not determined that there were cracks in the sample film that had been pulled out in a circular shape, but only those samples that had cracks were determined to have cracks.
The drop height was increased in 1 cm increments until the sample film was cracked, and a preliminary test was performed until the sample film was cracked. When cracks occurred in the sample film, the drop height was reduced by 1 cm, and when no cracks occurred, the drop height was increased by 1 cm. This test was conducted on 50 sample films, and the drop height at which half of the sample films were cracked was determined. A load was applied to the drop height to obtain a punching energy (J) by a drop impact test.
（５）ボイド体積率
光反射層のポリマーの密度および無機粒子の密度と、光拡散層におけるこれらの配合比率から、光拡散層にボイドがない場合の光拡散層の計算上の密度を求めた。この計算で用いた密度は、ポリエチレンテレフタレートが１．３９ｇ／ｃｍ３、硫酸バリウム粒子が４．５ｇ／ｃｍ３である。他方、積層フィルムから光反射層のみを分離し、単位体積当たりの重量を計り、光反射層の実密度を求めた。ボイド体積率を下記式で算出した。
ボイド体積率（％）＝（１−実密度／ボイドがない場合の計算上の密度）×１００
(5) Void volume ratio From the density of the polymer of the light reflection layer and the density of the inorganic particles and the blending ratio in the light diffusion layer, the calculated density of the light diffusion layer when no void is present in the light diffusion layer was obtained. . The density used in this calculation is 1.39 g / cm 3 for polyethylene terephthalate and 4.5 g / cm 3 for barium sulfate particles. On the other hand, only the light reflecting layer was separated from the laminated film, and the weight per unit volume was measured to determine the actual density of the light reflecting layer. The void volume ratio was calculated by the following formula.
Void volume fraction (%) = (1−actual density / calculated density without void) × 100
（６）各層の厚み比
日立製作所製Ｓ−４７００形電界放出形走査電子顕微鏡を用い、倍率５００倍にて、フィルムの断面を観察し、測定数５点の平均にてフィルムの各層の厚み比を求めた。
(6) Thickness ratio of each layer Using an S-4700 field emission scanning electron microscope manufactured by Hitachi, Ltd., the cross section of the film was observed at a magnification of 500 times, and the thickness ratio of each layer of the film was an average of 5 points measured. Asked.
（７）フィルムの厚み
接触式厚み計（アンリツ製 Ｋ−４０２Ｂ）を用いてフィルム厚みを測定した。
(7) Film thickness The film thickness was measured using a contact-type thickness meter (K-402B manufactured by Anritsu).
（８）打ち抜き性
穴あけ治具ＣＡＲＬ ＣＰ−５を用いて、フィルムを５０回打ち抜き（円形状の穴の直径は６ｍｍ、打ち抜く速度は５０回／１分間とした）、打ち抜いた端部を光学顕微鏡にて倍率２５倍にて観察しヒゲ状物の発生の有無とカエリの発生の有無を観察した。
ヒゲ状物については、打ち抜き部分から長さ１ｍｍ以上飛び出しているヒゲ状物がある打ち抜き穴を「発生有」とし、カエリについては、打ち抜き部分の一部または全部がフィルム平面を基準として０．５ｍｍ以上盛り上がっている打ち抜き穴を「発生有」とした。
ヒゲ状物およびカエリのそれぞれについて、下記式で発生割合を算出した。
発生割合（％）＝「発生有」の個数／５０個
(8) Punching property Using a hole punching tool CARL CP-5, the film was punched 50 times (the diameter of the circular hole was 6 mm, and the punching speed was 50 times / minute), and the punched end was optical microscope Was observed at a magnification of 25 times, and the presence or absence of whiskers and the occurrence of burrs were observed.
For whisker-like objects, a punched hole with a whisker-like object protruding 1 mm or more from the punched part is defined as “occurring”, and for burrs, a part or all of the punched part is 0.5 mm on the basis of the film plane. The punched holes that are raised above are defined as “occurring”.
The generation ratio was calculated by the following formula for each of the mustaches and burrs.
Occurrence rate (%) = number of occurrences / 50
［実施例１］
テレフタル酸ジメチル１３２重量部、イソフタル酸ジメチル１８重量部（ポリエステルの全ジカルボン酸成分を基準に１２モル％）、エチレングリコール９８重量部、ジエチレングリコール１．０重量部、酢酸マンガン０．０５重量部、酢酸リチウム０．０１２重量部を精留塔、留出コンデンサを備えたフラスコに仕込み、撹拌しながら１５０〜２３５℃に加熱しメタノールを留出させエステル交換反応を行った。メタノールが留出した後、リン酸トリメチル０．０３重量部、二酸化ゲルマニウム０．０４重量部を添加し、反応物を反応器に移した。ついで撹拌しながら反応器内を徐々に０．５ｍｍＨｇまで減圧するとともに２９０℃まで昇温し、重縮合反応を行い、ポリエステルを得た。得られたポリエステルを支持層および光反射層のポリエステルとして用い、平均粒径１．２μｍの硫酸バリウムのマスターバッチを作製し、支持層のポリエステル組成物には４重量％、光反射層のポリエステル組成物には５５重量％の含有量になるように添加量を調整した。
[Example 1]
132 parts by weight of dimethyl terephthalate, 18 parts by weight of dimethyl isophthalate (12 mol% based on the total dicarboxylic acid component of the polyester), 98 parts by weight of ethylene glycol, 1.0 part by weight of diethylene glycol, 0.05 part by weight of manganese acetate, acetic acid 0.012 parts by weight of lithium was charged into a rectification column and a flask equipped with a distillation condenser, and heated to 150 to 235 ° C. with stirring to distill methanol to conduct a transesterification reaction. After the methanol was distilled off, 0.03 part by weight of trimethyl phosphate and 0.04 part by weight of germanium dioxide were added, and the reaction product was transferred to the reactor. Next, while stirring, the pressure in the reactor was gradually reduced to 0.5 mmHg and the temperature was raised to 290 ° C. to conduct a polycondensation reaction, thereby obtaining a polyester. Using the obtained polyester as a polyester for the support layer and the light reflection layer, a master batch of barium sulfate having an average particle diameter of 1.2 μm was prepared. The polyester composition of the support layer was 4% by weight, and the polyester composition of the light reflection layer The amount added was adjusted to 55% by weight.
これらの原料を用い、それぞれ２７５℃に加熱された２台の押出機に供給し、支持層のポリエステル組成物と光反射層のポリエステル組成物とを、支持層／光反射層／支持層となるような３層フィードブロック装置を使用して合流させ、その積層状態を保持したままダイスよりシート状に成形した。支持層／光反射層／支持層の厚み比が二軸延伸後に４／９２／４となるように各押出機の吐出量で調整した。さらにこのシートを表面温度２３℃の冷却ドラムで冷却固化した未延伸フィルムを、表１に記載された予熱１（７３℃）および予熱２（７７℃）の温度にて加熱し、長手方向（縦方向）に延伸速度１０００％／秒にて９２℃にて３．０倍の倍率で延伸し、２５℃のロール群で冷却した。続いて、縦延伸したフィルムの両端をクリップで保持しながらテンターに導き、１１５℃にて予熱し、１２５℃に加熱された雰囲気中で長手に垂直な方向（横方向）に、５秒間で３．７倍の倍率で延伸した。その後テンター内で１９５℃の温度で熱固定を行い、テンター内で弛緩率２％で縦方向に弛緩し、１４５℃の温度にて幅入れ率２％で横方向に幅入れを行い、室温まで冷やして白色フィルムを得た。得られた白色フィルムは厚み２２５μｍ、反射率は９８．７％であった。評価結果を表３にまとめる。 These raw materials are used and supplied to two extruders each heated to 275 ° C., and the polyester composition of the support layer and the polyester composition of the light reflection layer become support layer / light reflection layer / support layer. Such a three-layer feed block device was used for merging, and the laminated state was maintained to form a sheet from a die. The thickness ratio of the support layer / light reflection layer / support layer was adjusted by the discharge amount of each extruder so that it became 4/92/4 after biaxial stretching. Further, an unstretched film obtained by cooling and solidifying the sheet with a cooling drum having a surface temperature of 23 ° C. is heated at a temperature of preheating 1 (73 ° C.) and preheating 2 (77 ° C.) shown in Table 1, and the longitudinal direction (longitudinal direction) Direction) at a stretching rate of 1000% / sec at a rate of 3.0 times at 92 ° C. and cooled by a roll group at 25 ° C. Subsequently, the both ends of the longitudinally stretched film are guided to a tenter while being held by clips, preheated at 115 ° C., and in an atmosphere heated to 125 ° C. in a direction perpendicular to the longitudinal direction (lateral direction) for 3 seconds in 5 seconds. The film was stretched at a magnification of 7 times. Then, heat setting is performed in the tenter at a temperature of 195 ° C., and in the tenter, the film is relaxed in the vertical direction with a relaxation rate of 2%. A white film was obtained after cooling. The obtained white film had a thickness of 225 μm and a reflectance of 98.7%. The evaluation results are summarized in Table 3.
［実施例２］
実施例１において支持層および光反射層の硫酸バリウム粒子の添加量をそれぞれ６重量％と６０重量％に変更し、硫酸バリウム粒子の平均粒径（ｄ５０）を表１記載のとおり変更した以外は実施例１同様にして白色フィルムを作成した。評価結果を表３にまとめる。
[Example 2]
In Example 1, the addition amount of the barium sulfate particles in the support layer and the light reflecting layer was changed to 6% by weight and 60% by weight, respectively, and the average particle diameter (d50) of the barium sulfate particles was changed as shown in Table 1. A white film was prepared in the same manner as in Example 1. The evaluation results are summarized in Table 3.
［実施例３］
実施例１において支持層のポリエステルを重合の段階でジカルボン酸成分としてイソフタル酸ジメチルを用いず、テレフタル酸ジメチルのみを用いて重合を行い、これの硫酸バリウムのマスターバッチを作成して、表１に記載の割合になるようにし、表２記載の延伸条件にて白色フィルムを作成した。評価結果を表３にまとめる。
[Example 3]
In Example 1, the support layer polyester was polymerized using only dimethyl terephthalate instead of dimethyl isophthalate as the dicarboxylic acid component in the polymerization stage, and a master batch of this barium sulfate was prepared. A white film was prepared under the stretching conditions shown in Table 2 so that the ratios were as described. The evaluation results are summarized in Table 3.
［実施例４］
実施例３において、支持層の無機粒子を平均粒子径（ｄ５０）０．２μｍのルチル型二酸化チタン粒子に変更し、光反射層の硫酸バリウム粒子として平均粒径（ｄ５０）１．２μｍのものを用いた他は、実施例３と同様にして白色フィルムを作成した。評価結果を表３にまとめる。
[Example 4]
In Example 3, the inorganic particles in the support layer were changed to rutile titanium dioxide particles having an average particle size (d50) of 0.2 μm, and the barium sulfate particles in the light reflecting layer had an average particle size (d50) of 1.2 μm. A white film was prepared in the same manner as in Example 3 except that it was used. The evaluation results are summarized in Table 3.
［実施例６，８，９、参考例１，２］
表１に記載された条件に変更する他は実施例１と同様にして白色フィルムを得た。なお実施例９は２層積層フィルムを作成したが、全て光反射層側から評価を行った。評価結果を表３にまとめる。
[Examples 6, 8, and 9, Reference Examples 1 and 2 ]
A white film was obtained in the same manner as in Example 1 except that the conditions were changed to those described in Table 1. In Example 9, a two-layer laminated film was prepared, but all were evaluated from the light reflecting layer side. The evaluation results are summarized in Table 3.
［比較例１〜７］
表１に記載された条件に変更する他は実施例１と同様にして白色フィルムを得た。なお比較例５は製膜性が非常に悪くフィルム破断のためサンプルが得られなかった。評価結果を表３にまとめる。
[Comparative Examples 1 to 7]
A white film was obtained in the same manner as in Example 1 except that the conditions were changed to those described in Table 1. In Comparative Example 5, no sample was obtained because the film-forming property was very poor and the film was broken. The evaluation results are summarized in Table 3.
本発明の反射板用白色フィルムは、液晶表示装置の反射フィルムとして好適に用いることができる。 The white film for a reflector of the present invention can be suitably used as a reflective film for a liquid crystal display device.
Claims (1)
［落下衝撃試験による打ち抜きエネルギーの試験方法］
デュポン式衝撃試験（ＪＩＳ Ｋ５６００−５−３、ＩＳＯ６２７２）に基づき、２５℃、５０％ＲＨ環境下で調整されたサンプルフィルム（３０ｍｍ×３０ｍｍ）を受台の上にセットし、撃芯（直径４ｍｍの円柱状、材質ＳＵＳ）をサンプルフィルムの上に設置し、おもり（荷重３００ｇｆ）を撃芯の上に落下させ、サンプルフィルム５０枚の半数に割れが生じる落下高さを求め、かかる落下高さに荷重を掛けて、落下衝撃試験による打ち抜きエネルギー（Ｊ）とした。 A light reflecting layer in which voids are formed in an aromatic polyester and the void volume ratio is 55 to 80%, and a biaxially stretched aromatic polyester film supporting layer provided on at least one surface thereof. The ratio of the total thickness to the total thickness of the support layer is 92: 8 to 98: 2, the reflectivity of the film is 98.0% or more, and burrs and whiskers are less likely to occur during cutting. Therefore, the white aromatic polyester film for a reflector is characterized in that the punching energy by a drop impact test required by the following test method is 0.10 to 0.30 J, and the film thickness is 150 to 250 μm.
[Test method of punching energy by drop impact test]
Based on the DuPont impact test (JIS K5600-5-3, ISO 6272), a sample film (30 mm × 30 mm) adjusted in an environment of 25 ° C. and 50% RH is set on a cradle, and a strike core (diameter 4 mm) Is placed on the sample film, the weight (load 300 gf) is dropped on the strike core, and the drop height at which half of the 50 sample films are cracked is determined. A load was applied to the punching energy (J) in the drop impact test.
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| JP2009155283A JP5629064B2 (en) | 2009-06-30 | 2009-06-30 | White film for reflector |
| PCT/JP2010/054820 WO2010110211A1 (en) | 2009-03-25 | 2010-03-19 | White film for reflector |
| CN201080013427.5A CN102362217B (en) | 2009-03-25 | 2010-03-19 | White film for reflector |
| KR1020117020486A KR101640273B1 (en) | 2009-03-25 | 2010-03-19 | White film for reflector |
| TW099108704A TWI488743B (en) | 2009-03-25 | 2010-03-24 | Reflector with white film |
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| JP5985808B2 (en) * | 2011-10-20 | 2016-09-06 | 帝人デュポンフィルム株式会社 | Polyester film for reflector |
| JP6356447B2 (en) * | 2014-03-17 | 2018-07-11 | 帝人フィルムソリューション株式会社 | White polyester film |
| JP2017195352A (en) * | 2016-04-14 | 2017-10-26 | 大日本印刷株式会社 | Light emitting diode mounting module |
| JP2017198752A (en) * | 2016-04-25 | 2017-11-02 | 大日本印刷株式会社 | Light reflection sheet |
| JP2017199737A (en) * | 2016-04-25 | 2017-11-02 | 大日本印刷株式会社 | Light emitting diode-mounted module, and light reflective member for light emitting diode-mounted module |
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| JP4577540B2 (en) * | 2000-06-06 | 2010-11-10 | 東洋紡績株式会社 | Cavity-containing polyester release film |
| JP2006274254A (en) * | 2005-03-02 | 2006-10-12 | Daicel Chem Ind Ltd | Aliphatic polyester having low branching degree and high molecular weight, method for producing the same, molded article and film |
| JPWO2007069541A1 (en) * | 2005-12-12 | 2009-05-21 | 三菱樹脂株式会社 | Reflective film |
| JP5098337B2 (en) * | 2006-02-03 | 2012-12-12 | 東レ株式会社 | Light reflecting sheet made of ultrafine fibers and liquid crystal display provided with the same |
| JP4548430B2 (en) * | 2006-03-02 | 2010-09-22 | 東レ株式会社 | White laminated polyester film for reflector |
| JP2007298963A (en) * | 2006-04-07 | 2007-11-15 | Toray Ind Inc | White polyester film for liquid crystal reflector, and surface light source using the film |
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| JP2008065142A (en) * | 2006-09-08 | 2008-03-21 | Denki Kagaku Kogyo Kk | Light diffusion sheet |
| JP2008088207A (en) * | 2006-09-29 | 2008-04-17 | Asahi Kasei Chemicals Corp | Polytrimethylene terephthalate resin composition foam sheet and method for producing the same |
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