TWI390296B - Light-diffusion plate - Google Patents
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Description
本發明係有關於一種可供用於液晶顯示器(LCD)背光單元或一照明裝置的光擴散板。The present invention relates to a light diffusing plate that can be used in a liquid crystal display (LCD) backlight unit or a lighting device.
習用光擴散板曾揭示(1)一種經由物理過程而具有表面凸部的光擴散板(日本昭和4－275501號專利公開公報)，(2)一種在一聚酯樹脂的透明基板上塗布一道含有透明樹脂粒子之光擴散層而獲得的光擴散板(日本昭和6－59108號專利公開公報)，(3)一種使珠粒與透明樹脂進行熔融混合，再對珠粒與樹脂混合物予以壓出成形而獲得的光擴散板(日本昭和6－123802號專利公開公報)，和(4)對至少二種透明熱塑性樹脂予以熔融揉合而形成一種具有海島狀結構的光擴散板(日本昭和9－311205號專利公開公報)。A conventional light diffusing plate has disclosed (1) a light diffusing plate having a surface convex portion via a physical process (Japanese Patent Publication No. Hei 4-275501), and (2) a coating on a transparent substrate of a polyester resin. A light-diffusing sheet obtained by a light-diffusion layer of a transparent resin particle (Japanese Patent Publication No. Hei 6-59108), (3) a method in which a bead is melt-mixed with a transparent resin, and the bead and the resin mixture are extruded. And the obtained light diffusing plate (Japanese Patent Publication No. Hei 6-123802), and (4) melt-kneading at least two kinds of transparent thermoplastic resins to form a light diffusing plate having an island-like structure (Showa 9-311205, Japan) No. Patent Publication).
前述(1)和(2)項的光擴散板屬於可利用表面凸部或光擴散塗層而展現出光擴散效果的表面光擴散板。此外，前述(3)和(4)項的光擴散板則為即使在基板亦含有光擴散組分的光擴散板。The light diffusing plate of the above items (1) and (2) belongs to a surface light diffusing plate which can exhibit a light diffusing effect by using a surface convex portion or a light diffusing coating. Further, the light diffusing plate of the above items (3) and (4) is a light diffusing plate containing a light diffusing component even on the substrate.
通常，以甲基丙烯酸甲酯樹脂為主而製備的光擴散板，其優點在於具有諸如總透光率之類的優越光性質。然而，由於這種光擴散板的形穩性低，因而在與冷陰極螢光燈或LED(發光二極體)之類的光源合用時，且在打開或關掉光源而引起溫度的變化時，光擴散板的吸水率易於改變，以致造成包括形變在內的問題，從而導致彎折、折皺或龜裂。也就是說，在高溫和高濕條件下，很可能發生諸如彎折現象之類的形變(日本昭和07－10098和08－198976號專利公開公報)。In general, a light diffusing plate prepared mainly of a methyl methacrylate resin has an advantage in that it has superior light properties such as total light transmittance. However, since the shape of the light diffusing plate is low, when it is used together with a light source such as a cold cathode fluorescent lamp or an LED (light emitting diode), and when the light source is turned on or off to cause a temperature change. The water absorption rate of the light diffusing plate is apt to change, causing problems including deformation, resulting in bending, wrinkles or cracks. That is to say, under high temperature and high humidity conditions, deformation such as a bending phenomenon is likely to occur (Japanese Laid-Open Patent Publication No. Hei 07-10098 and No. 08-198976).
為解決這些問題，有人曾提出含有甲基丙烯酸甲酯－苯乙烯而能減低吸收力的多層板(日本第2004－37483號專利公開公報及韓國第2003－95262號專利公開公報)。然而，所用樹脂的耐光性實際上不足，因而可能引起諸如著色之類的變質情形。作為已知的一種製程，是可添加紫外線吸收劑，據以改良樹脂的耐光性。然而，在某些耐光性低的樹脂中，該等改良效果並不顯著。In order to solve these problems, a multilayer board containing methyl methacrylate-styrene and having an improved absorption has been proposed (Japanese Patent Publication No. 2004-37483 and Japanese Patent Publication No. 2003-95262). However, the light resistance of the resin used is practically insufficient, and thus may cause deterioration such as coloring. As a known process, an ultraviolet absorber can be added to improve the light resistance of the resin. However, in some resins having low light resistance, these improvement effects are not remarkable.
為免發生相關習用技術所遭遇的問題，本案發明人在對光擴散板從事密集與徹底的研究後提出本發明，據以開發一種縱然在高溫及高濕條件下仍因為具有高度耐熱性和保持低吸收性能，以致形穩性高，且因表面層的耐光性，從而縱使長期曝露於光源中亦無發黃現象的光擴散板。In order to avoid the problems encountered in the related art, the inventor of the present invention proposed the present invention after conducting intensive and thorough research on the light diffusing plate, thereby developing a high heat resistance and maintaining even under high temperature and high humidity conditions. The low-absorption property, so that the shape stability is high, and the light-diffusing property of the surface layer is long, even if it is exposed to the light source for a long period of time, there is no yellowing phenomenon.
所以，本發明之目的在於提供一種具有高度形穩性的光擴散板，因而縱然在高溫和高濕條件下也甚少造成彎折現象。SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a light diffusing plate having a high degree of dimensional stability, which causes little bending even under high temperature and high humidity conditions.
本發明的另一目的是提供一種能以較低成本製造且仍能保持高度形穩性的光擴散板。Another object of the present invention is to provide a light diffusing plate which can be manufactured at a lower cost and which still maintains a high degree of dimensional stability.
本發明的再一目的是提供一種甚少產生發黃現象的光擴散板。It is still another object of the present invention to provide a light diffusing plate which produces little yellowing.
為達成前述各目的，本發明提供一種光擴散板，其包含有一以聚碳酸酯樹脂(polycarbonate resin)作為樹脂主劑(base resin)的基板層。In order to achieve the foregoing objects, the present invention provides a light diffusing plate comprising a substrate layer using a polycarbonate resin as a resin base resin.
此外，本發明也提供一種光擴散板，其包括一以聚碳酸酯樹脂及聚苯乙烯樹脂混合物作為樹脂主劑之基板層。Further, the present invention also provides a light diffusing plate comprising a substrate layer comprising a polycarbonate resin and a polystyrene resin mixture as a resin main component.
該聚碳酸酯樹脂可以是從下列構成之群組中選用者：由二羥基酚與光氣或二羥基酚與碳酸酯先質經反應作用而製備的線性及支鏈芳族聚碳酸酯均聚物。The polycarbonate resin may be selected from the group consisting of homopolymerized linear and branched aromatic polycarbonates prepared by reacting a dihydric phenol with phosgene or a dihydric phenol with a carbonate precursor. Things.
該樹脂主劑可包括一種按1：9~9：1重量比例予以混合的聚碳酸酯樹脂及聚苯乙烯樹脂混合物。The resin base agent may include a polycarbonate resin and a polystyrene resin mixture which are mixed in a weight ratio of 1:9 to 9:1.
依據ASTM D1238標準，在1.2 kg的負荷下，該聚碳酸酯樹脂於300℃時的熔融指數可為8~30 g/10分鐘。According to the ASTM D1238 standard, the polycarbonate resin may have a melt index of 8 to 30 g/10 minutes at 300 ° C under a load of 1.2 kg.
依ASTM D1238標準，在5 kg的負荷下，該聚苯乙烯酸樹脂於200℃時的熔融指數為0.5~3 g/10分鐘。According to the ASTM D1238 standard, the melt index of the polystyrene resin at 200 ° C is 0.5 to 3 g/10 minutes under a load of 5 kg.
該光擴散板可另包括在基板層的一或兩面上所形成，並含有丙烯酸樹脂或苯乙烯－丙烯酸共聚物樹脂作為樹脂主劑的表面層。The light diffusing plate may further include a surface layer formed on one or both sides of the substrate layer and containing an acrylic resin or a styrene-acrylic copolymer resin as a resin main component.
該丙烯酸樹脂可以是從下列構成之群組中選用的至少一種單體所獲得的均聚物，共聚物或其混合物：甲基丙烯酸烷基酯，丙烯酸烷基酯，甲基丙烯酸環烷基酯，丙烯酸環烷基酯，甲基丙烯酸芳基酯，以及丙烯酸芳基酯。The acrylic resin may be a homopolymer, a copolymer or a mixture thereof obtained from at least one monomer selected from the group consisting of alkyl methacrylate, alkyl acrylate, cycloalkyl methacrylate. , cycloalkyl acrylate, aryl methacrylate, and aryl acrylate.
該苯乙烯－丙烯酸共聚物樹脂，可以是從甲基丙烯酸烷基酯，丙烯酸烷基酯，甲基丙烯酸環烷基酯，丙烯酸環烷基酯，甲基丙烯酸芳基酯，以及丙烯酸芳基酯所構成之群組中所選用的至少一種丙烯酸單體，與從苯乙烯，α－甲基苯乙烯，間甲基苯乙烯，對甲基苯乙烯以及對甲氧基苯乙烯所構成之群組中所選用的至少一種苯乙烯單體，經共聚而成的共聚物。The styrene-acrylic copolymer resin may be an alkyl methacrylate, an alkyl acrylate, a cycloalkyl methacrylate, a cycloalkyl acrylate, an aryl methacrylate, and an aryl acrylate. At least one acrylic monomer selected from the group consisting of: styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, and p-methoxystyrene a copolymer obtained by copolymerizing at least one styrene monomer selected.
該苯乙烯－丙烯酸共聚物樹脂可以讓該丙烯酸單體與該苯乙烯單體按6：4~2：8的重量比例經反應作用而獲得者。The styrene-acrylic copolymer resin can be obtained by reacting the acrylic monomer with the styrene monomer in a weight ratio of 6:4 to 2:8.
該表面層可另包括一氟樹脂或氟樹脂粒子。The surface layer may further comprise a fluororesin or fluororesin particles.
該基板層或該表面層，以各自之組成的總重量為準，可分別另包括0.1~35 wt%(重量百分比)的光擴散劑。The substrate layer or the surface layer may further comprise 0.1 to 35 wt% of a light diffusing agent, respectively, based on the total weight of the respective compositions.
該光擴散劑的粒度可為0.2~50 μm。The light diffusing agent may have a particle size of 0.2 to 50 μm.
該表面層可具有因光擴散劑凸出而形成的浮凸形狀，其表面粗糙度為1~50 μm。The surface layer may have an embossed shape formed by the protrusion of the light diffusing agent, and has a surface roughness of 1 to 50 μm.
該基板層或該表面層，以各自之組成的總重量為準，可分別另包括0.01~5 wt%的光穩定劑。The substrate layer or the surface layer may further comprise 0.01 to 5 wt% of a light stabilizer, respectively, based on the total weight of the respective compositions.
茲將本發明詳予說明於後。The invention is described in detail below.
本發明的光擴散板，包含有一只含有一種聚碳酸酯樹脂或者一種包含有一聚碳酸酯樹脂及一聚苯乙烯樹脂之混合物作為一種樹脂主劑(base resin)的基板層。The light diffusing plate of the present invention comprises a substrate layer comprising a polycarbonate resin or a mixture comprising a polycarbonate resin and a polystyrene resin as a resin base resin.
該聚碳酸酯樹脂擁有優越的耐衝擊性，透光率，耐寒性及電氣性質，尤其是具有高度的耐熱性與耐吸收性，以致形穩性優異，並具有寬廣的溫度範圍。因此，這種樹脂主要是用於光學透鏡，光碟材料，頭盔，護罩，遮蓋等。The polycarbonate resin has excellent impact resistance, light transmittance, cold resistance and electrical properties, especially high heat resistance and absorption resistance, so that it has excellent dimensional stability and a wide temperature range. Therefore, this resin is mainly used for optical lenses, optical disc materials, helmets, shields, covers, and the like.
本發明所用的該聚碳酸酯樹脂，是一般的芳族聚碳酸酯樹脂，包括線性或支鏈碳酸酯均聚物，聚酯共聚物，或前述之混合物；其係由二羥基酚與光氣或二羥基酚與碳酸酯先質經反應作用而產生者。就此而論，二羥基酚的範例有2,2－雙(4－羥苯基)丙烷(雙酚A)，雙(4－羥苯基)甲烷，2,2－雙(4－羥基－3,5－二甲苯基)丙烷，和1,1－雙(4－羥苯基)環己烷。而該碳酸酯先質的範例則有碳酸二苯酯，鹵化羰，和二芳基碳酸酯。The polycarbonate resin used in the present invention is a general aromatic polycarbonate resin comprising a linear or branched carbonate homopolymer, a polyester copolymer, or a mixture thereof, which is composed of a dihydric phenol and phosgene. Or a dihydric phenol and a carbonate precursor are produced by reaction. In this connection, examples of dihydric phenols are 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3). , 5-dimethylphenyl)propane, and 1,1-bis(4-hydroxyphenyl)cyclohexane. Examples of such carbonate precursors are diphenyl carbonate, halogenated carbonyl, and diaryl carbonate.
依ASTM D1238標準，在1.2 kg的負荷下，該聚碳酸酯樹脂於300℃時的熔融指數(MI)宜為7~30 g/10分鐘。According to the ASTM D1238 standard, the melt index (MI) of the polycarbonate resin at 300 ° C is preferably 7 to 30 g/10 minutes under a load of 1.2 kg.
該聚碳酸酯樹脂雖具有優越的耐衝擊性，耐吸收性及透光率，但價格昂貴卻是其缺點。因此，可讓聚碳酸酯樹脂跟具有類似折射率和價格較廉的聚苯乙烯樹脂混合，以便強化聚碳酸酯樹脂的剛性，降低製備成本中的物料費用，和維持及增進光學和機械性質。Although the polycarbonate resin has excellent impact resistance, absorption resistance, and light transmittance, it is expensive but it is a disadvantage. Therefore, the polycarbonate resin can be mixed with a polystyrene resin having a similar refractive index and a relatively low price in order to strengthen the rigidity of the polycarbonate resin, reduce the material cost in the production cost, and maintain and enhance the optical and mechanical properties.
製備基板層之樹脂主劑所用的聚苯乙烯樹脂因為堅硬、無色、透明、價格不貴(量產的關係)，以及具有良好的電氣特性，所以已被廣泛用於諸如廚房用具、書寫材料和傢俱等之類的日用品，以及諸如大型汽車模具與電視機殼等之類的電器用品。The polystyrene resin used for preparing the resin base of the substrate layer has been widely used for such as kitchen utensils, writing materials, and the like because it is hard, colorless, transparent, inexpensive (production relationship), and has good electrical properties. Daily necessities such as furniture, and electrical appliances such as large automobile molds and TV cases.
依ASTM D1238標準，在5 kg的負荷下，本發明所用聚苯乙烯樹脂於200℃時的熔融指數(MI)為0.5~3 g/10分鐘。According to the ASTM D1238 standard, the melt index (MI) of the polystyrene resin used in the present invention at 200 ° C is 0.5 to 3 g/10 minutes under a load of 5 kg.
如欲讓聚碳酸酯樹脂跟聚苯乙烯樹脂混合時，可在200~300℃，但以250℃為宜的溫度下，使用螺桿直徑為30 mm的雙螺桿擠壓機，按250 rpm的馬達轉速對這些樹脂進行熔融揉合。If you want to mix polycarbonate resin with polystyrene resin, you can use a twin-screw extruder with a screw diameter of 30 mm and a motor with 250 rpm at 200~300 °C, but at a temperature of 250 °C. These resins are melt-kneaded at a rotational speed.
就此而論，該聚碳酸酯樹脂及該聚苯乙烯樹脂可按1：9~9：1的比例加以混合。各該樹脂的添加量至少應為10%，以便展現出聚碳酸酯樹脂的優點，例如撓性和形穩性，以及聚苯乙烯的優點，例如高度耐吸收性和強度。In this connection, the polycarbonate resin and the polystyrene resin may be mixed in a ratio of 1:9 to 9:1. Each of the resins should be added in an amount of at least 10% in order to exhibit advantages of polycarbonate resin such as flexibility and shape stability, and advantages of polystyrene such as high absorbency and strength.
本發明的光擴散板可以是只由含有前述樹脂主劑之基板層所構成的單層光擴散板，或是由該基板層與在其一邊或兩邊表面上形成之表面層共同構成的多層光擴散板。The light diffusing plate of the present invention may be a single-layer light diffusing plate composed only of a substrate layer containing the above-mentioned resin main agent, or a multilayer light composed of the substrate layer and a surface layer formed on one or both sides thereof. Diffuser plate.
以多層光擴散板來說，除了前述的基板層外，尚可在該基板層的一邊或兩邊表面上形成表面層。就此而論，表面層的樹脂主劑雖未特別限定，但可採用丙烯酸樹脂或苯乙烯－丙烯酸共聚物樹脂。In the case of the multilayer light diffusing plate, in addition to the aforementioned substrate layer, a surface layer may be formed on one or both sides of the substrate layer. In this connection, the resin main component of the surface layer is not particularly limited, but an acrylic resin or a styrene-acrylic copolymer resin may be used.
該丙烯酸樹脂宜為從下列構成之群組中選用的至少一種單體所獲得的均聚物或共聚物：甲基丙烯酸烷基酯，例如甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯、和甲基丙烯酸－2－乙基己酯等；丙烯酸烷基酯，例如丙烯酸甲酯、丙烯酸乙酯、和丙烯酸丁酯等；甲基丙烯酸環烷基酯，例如甲基丙烯酸環己酯、甲基丙烯酸－2－甲基環己酯、和甲基丙烯酸二環戊酯等；丙烯酸環烷基酯，例如丙烯酸環己酯、和丙烯酸－2－甲基環己酯等；甲基丙烯酸芳基酯，例如甲基丙烯酸苯酯、和甲基丙烯酸苄酯等；以及丙烯酸芳基酯，例如丙烯酸苯酯、和丙烯酸苄酯等。The acrylic resin is preferably a homopolymer or a copolymer obtained from at least one monomer selected from the group consisting of alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, methyl group. Butyl acrylate, and 2-ethylhexyl methacrylate and the like; alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate; etc.; cycloalkyl methacrylates such as methacrylic acid rings Hexyl ester, 2-methylcyclohexyl methacrylate, and dicyclopentyl methacrylate; etc.; cycloalkyl acrylates such as cyclohexyl acrylate, and 2-methylcyclohexyl acrylate; Aryl acrylates such as phenyl methacrylate, and benzyl methacrylate; and the like, and aryl acrylates such as phenyl acrylate, and benzyl acrylate.
該苯乙烯－丙烯酸共聚物樹脂，係使用上述之樹脂作為丙烯酸單體，以及苯乙烯或取代苯乙烯作為苯乙烯單體而予以製備。取代苯乙烯的範例包括諸如α－甲基苯乙烯的烷基苯乙烯，諸如氯苯乙烯的鹵化苯乙烯，以及乙烯基苯乙烯。此外，必要時也可採用二種或以上的苯乙烯單體。The styrene-acrylic copolymer resin is prepared by using the above-mentioned resin as an acrylic monomer, and styrene or substituted styrene as a styrene monomer. Examples of the substituted styrene include alkylstyrene such as ?-methylstyrene, halogenated styrene such as chlorostyrene, and vinylstyrene. Further, two or more kinds of styrene monomers may be used as necessary.
尤其，在本發明所用的苯乙烯－丙烯酸共聚物樹脂中，該丙烯酸單體及該苯乙烯單體的共聚比例為9：1~1：9，但以6：4~1：9的比例較宜。考慮到對基板層的黏附性，這些單體宜以前述比例使用。In particular, in the styrene-acrylic copolymer resin used in the present invention, the copolymerization ratio of the acrylic monomer and the styrene monomer is from 9:1 to 1:9, but in a ratio of from 6:4 to 1:9. should. These monomers are preferably used in the aforementioned ratio in view of adhesion to the substrate layer.
此外，本發明的表面層可另含有一種氟樹脂或氟樹脂粒子。Further, the surface layer of the present invention may further contain a fluororesin or fluororesin particles.
該氟樹脂具有優越的熱穩定性及電氣性質，也擁有良好的耐化學性，耐候性，耐光性與耐氧力，尤其具有極低的吸水率和高度的耐熱性，所以工作溫度可高達250~300℃。另外，由於這樹脂具有優異的表面耐摩擦性，因而目前被應用到種種不同的閥件、泵浦、過濾器、管件、纜線和電腦上，也被航太工業廣泛採用。The fluororesin has excellent thermal stability and electrical properties, and also has good chemical resistance, weather resistance, light resistance and oxygen resistance, especially low water absorption and high heat resistance, so the operating temperature can be as high as 250 ~300 °C. In addition, because of its excellent surface abrasion resistance, this resin is currently used in a wide variety of valve parts, pumps, filters, fittings, cables and computers, and is widely used by the aerospace industry.
尤其，本發明所用的氟樹脂或氟樹脂粒子包括從下列選用的至少一種：四氟乙烯(TFE)均聚物，四氟乙烯與全氟丙醚共聚物(PFA)，四氟乙烯(TFE)與六氟丙烯(HFP)共聚物，四氟乙烯與乙烯共聚物(ETFE)，以及亞乙烯氟(vinylidenefluoride，VDF)與四氟乙烯(TFE)共聚物。使用氟樹脂或氟樹脂粒子後，會產生良好的拒水性。也就是說，讓表面層含有氟樹脂，據以進一步增進形穩性。結果，縱然是在高溫和高濕條件下，也不會發生彎折現象。In particular, the fluororesin or fluororesin particles used in the present invention include at least one selected from the group consisting of tetrafluoroethylene (TFE) homopolymer, tetrafluoroethylene and perfluoropropyl ether copolymer (PFA), and tetrafluoroethylene (TFE). Copolymer with hexafluoropropylene (HFP), copolymer of tetrafluoroethylene and ethylene (ETFE), and copolymer of vinylidenefluoride (VDF) and tetrafluoroethylene (TFE). When a fluororesin or a fluororesin particle is used, good water repellency is produced. That is, the surface layer is made to contain a fluororesin to further enhance the dimensional stability. As a result, even under high temperature and high humidity conditions, the bending phenomenon does not occur.
以表面層的總組成為準，表面層中的氟樹脂含量宜為0.5~35 wt%(重量百分比)，但考慮到形穩性及透光率，應以5~15 wt%較宜。The content of the fluororesin in the surface layer is preferably 0.5 to 35 wt% (weight percent) based on the total composition of the surface layer, but considering the shape stability and the light transmittance, it should be 5 to 15 wt%.
此外，基板層或表面層可另含有一種折射率與樹脂主劑不同的光擴散劑，以供增加光的擴散率。為達成此目的，可採用種種不同的有機或無機粒子。就此而論，如果這種光擴散劑的折射率與樹脂主劑有很大的差異，那麼縱然用量很少，也可展現出意欲的光擴散效果。另一方面，若是折射率的差異小，該材料的用量便應較大。Further, the substrate layer or the surface layer may further contain a light diffusing agent having a refractive index different from that of the resin main agent for increasing the diffusivity of light. Various organic or inorganic particles can be used for this purpose. In this connection, if the refractive index of the light diffusing agent is greatly different from that of the resin main agent, the intended light diffusing effect can be exhibited even if the amount is small. On the other hand, if the difference in refractive index is small, the amount of the material should be large.
通常，有機粒子的範例有丙烯酸聚合物粒子，例如甲基丙烯酸甲酯，甲基丙烯酸乙酯，甲基丙烯酸異丁酯，甲基丙烯酸正丁酯，甲基丙烯酸正丁基甲酯，丙烯酸，甲基丙烯酸，甲基丙烯酸羥基乙酯，甲基丙烯酸羥基丙酯，丙烯酸羥基乙酯，丙烯醯胺，羥甲基丙烯醯胺，甲基丙烯酸縮水甘油酯，丙烯酸乙酯，丙烯酸異丁酯，丙烯酸正丁酯，丙烯酸－2－乙基己酯聚合物，或其共聚物或三元共聚物；烯烴聚合物粒子，例如聚乙烯與聚丙烯；丙烯－烯烴共聚物粒子，先形成一道均聚物、共聚物或三元共聚物粒子層，再將另一單體層施用到前述聚合物粒子層上而獲得的多層多組分粒子，矽氧烷聚合物粒子，四氟乙烯粒子等。In general, examples of organic particles are acrylic polymer particles such as methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, n-butyl methacrylate, acrylic acid, methyl Acrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, acrylamide, methylol acrylamide, glycidyl methacrylate, ethyl acrylate, isobutyl acrylate, acrylic acid Butyl ester, 2-ethylhexyl acrylate polymer, or a copolymer or terpolymer thereof; olefin polymer particles, such as polyethylene and polypropylene; propylene-olefin copolymer particles, first forming a homopolymer, A copolymer or a terpolymer particle layer, and a multilayered multicomponent particle obtained by applying another monomer layer to the above polymer particle layer, a siloxane polymer particle, a tetrafluoroethylene particle or the like.
無機光擴散粒子的範例包括碳酸鈣，硫酸鋇，氧化矽，氫氧化鋁，氧化鈦，氧化鋯，氟化鎂，滑石，玻璃，雲母等。大體上，有機粒子的光擴散性優於無機粒子。另外，如有必要時，可讓至少兩種光擴散粒子混合。Examples of the inorganic light-diffusing particles include calcium carbonate, barium sulfate, barium oxide, aluminum hydroxide, titanium oxide, zirconium oxide, magnesium fluoride, talc, glass, mica and the like. In general, organic particles have better light diffusibility than inorganic particles. In addition, at least two kinds of light-diffusing particles may be mixed if necessary.
表面層另含有光擴散劑時，可進一步增加光擴散效果。此外，該等光擴散粒子還會從表面層的表面凸出，以致使其浮凸而展現出非光澤表面和低的反射率。就此而論，表面層的表面粗糙度宜約為0.1~50 μm。這粗糙度如超過50 μm，表面的耐衝擊強度就變得不足。反之，這粗糙度若是低於0.1 μm，就會減損非光澤的效果。When the surface layer further contains a light diffusing agent, the light diffusing effect can be further increased. In addition, the light-diffusing particles also protrude from the surface of the surface layer such that they emboss to exhibit a non-glossy surface and low reflectance. In this connection, the surface roughness of the surface layer is preferably about 0.1 to 50 μm. If the roughness exceeds 50 μm, the impact strength of the surface becomes insufficient. Conversely, if the roughness is less than 0.1 μm, the non-gloss effect will be degraded.
以本發明基板層或表面層之樹脂主劑組成的總重量為準，該基板層或表面層中的光擴散劑含量為0.01~35 wt%，並以0.5~15 wt%為宜。光擴散劑的含量低於0.01 wt%時，就難以期望達到充分的光擴散效果或遮罩效果。另一方面，如含量超過35 wt%時，透光率即變差。就此而論，光擴散劑的含量可視其與樹脂主劑的折射率差異而決定。The content of the light diffusing agent in the substrate layer or the surface layer is 0.01 to 35 wt%, and preferably 0.5 to 15 wt%, based on the total weight of the resin base agent of the substrate layer or the surface layer of the present invention. When the content of the light diffusing agent is less than 0.01% by weight, it is difficult to achieve a sufficient light diffusing effect or a masking effect. On the other hand, when the content exceeds 35 wt%, the light transmittance is deteriorated. In this connection, the content of the light diffusing agent can be determined depending on the difference in refractive index from the resin main agent.
此外，基板層或表面層可另含有一種光穩定劑。光穩定劑的範例包括一種最大吸收波長為250~380 nm的紫外線吸收劑，或諸如受阻胺(hindered amine)紫外線穩定劑之類能使光穩定效果發揮到最大程度的一種自由基清除劑。這組分應長期展現出該效果，且不得因為蒸發或萃取而與板片分離或離開。所選用的吸收劑應與基板具有高度相容性。Further, the substrate layer or the surface layer may additionally contain a light stabilizer. Examples of light stabilizers include a UV absorber having a maximum absorption wavelength of 250 to 380 nm, or a radical scavenger such as a hindered amine UV stabilizer which maximizes the photostability effect. This component should exhibit this effect for a long time and must not separate or leave the sheet due to evaporation or extraction. The absorbent selected should be highly compatible with the substrate.
該紫外線吸收劑可以是從下列構成之群組中所選用者：氰基丙烯酸(cyanoacryl)，水楊酸(salicylate)，丙二酸酯(malonic acid ester)，草酸醯基苯胺(oxalic anilide)，二酮(diketone)，羥基二苯甲酮(hydroxyl benzophenone)，羥基苯并***(hydroxy benzotriazole)，有機金屬，及其混合物。The ultraviolet absorber may be selected from the group consisting of cyanoacryl, salicylate, malonic acid ester, oxalic anilide, Diketone, hydroxyl benzophenone, hydroxy benzotriazole, organometallics, and mixtures thereof.
該紫外線穩定劑可以是從下列構成之群組中所選用者：哌啶基酯(piperidinyl ester)，噁唑烷(oxazolidine)與哌啶基噁唑(piperidino－oxazolidine)，哌啶基螺縮醛(piperidispiroacetal)，二氮雜環烷酮(diazacycloalkanone)，及其混合物。The UV stabilizer may be selected from the group consisting of: piperidinyl ester, oxazolidine and piperidino-oxazolidine, piperidinyl acetal (piperidispiroacetal), diazacycloalkanone, and mixtures thereof.
以基板層或表面層之樹脂組成的總重量為準，光穩定劑的用量可以是0.01~5 wt%，並以0.1~2 wt%為宜。尤其，表面層如含有這種組分時，就可在基板層之總透光率或物理性質不受減損的情況下達到光穩定效果。The light stabilizer may be used in an amount of 0.01 to 5 wt%, and preferably 0.1 to 2 wt%, based on the total weight of the resin composition of the substrate layer or the surface layer. In particular, when the surface layer contains such a component, the light stabilizing effect can be achieved without degrading the total light transmittance or physical properties of the substrate layer.
本發明的光擴散板可供用於種種的室內及室外用途。也就是說，此種光擴散板可應用到招牌，發光告示牌，發光罩，玻璃展示箱等，但以作為顯示器的光擴散板為宜。顯示器用光擴散板的範例通常是LCD(液晶顯示器)背光單元或端面照光式(edge－light－type)背光單元用的光擴散板。The light diffusing plate of the present invention can be used for a variety of indoor and outdoor applications. That is to say, the light diffusing plate can be applied to a signboard, a light-emitting signboard, a light-emitting cover, a glass display case, etc., but it is preferable to use a light diffusing plate as a display. An example of a light diffusing plate for a display is usually an LCD (liquid crystal display) backlight unit or a light diffusing plate for an edge-light-type backlight unit.
藉由以下所列舉的若干實施例，可更加瞭解本發明，惟該等實施例僅為說明之目的而列舉，不得解釋成據以限制本發明。The invention may be further understood by the following examples of the invention, which are not to be construed as limiting the invention.
所舉範例中係以PC和PS作為基板層的樹脂主劑，它們係以表1所示的組成比例予以均勻添加，再使用雙螺桿擠壓機，於250℃溫度條件下進行熔融揉合。In the example, PC and PS were used as the resin main components of the substrate layer, and they were uniformly added in the composition ratio shown in Table 1, and then melt-kneaded at a temperature of 250 ° C using a twin-screw extruder.
就此而論，依ASTM D1238標準，在1.2 kg的負荷下，該聚碳酸酯樹脂於300℃時的熔融指數為22 g/10分鐘。另外，依ASTM D1238標準，在5 kg的負荷下，聚苯乙烯樹脂於200℃時的熔融指數則為1.5 g/10分鐘。In this connection, according to the ASTM D1238 standard, the polycarbonate resin has a melt index of 22 g/10 minutes at 300 ° C under a load of 1.2 kg. In addition, according to the ASTM D1238 standard, the melt index of the polystyrene resin at 200 ° C is 1.5 g/10 min under a load of 5 kg.
此外，表面層的樹脂主劑，是採用聚甲基丙烯酸甲酯，聚苯乙烯，或以丙烯酸單體與苯乙烯單體依一般製程共聚而得苯乙烯－丙烯酸共聚物樹脂。Further, the resin base agent of the surface layer is a polystyrene-acrylic copolymer resin obtained by polymethyl methacrylate, polystyrene, or copolymerization of an acrylic monomer and a styrene monomer according to a general process.
光擴散板是採用螺桿直徑為135 mm和60 mm的擠壓機，經由共擠壓製程而在250℃的溫度條件下形成。在光擴散板只由一基板層所構成之情況時，該基板層的厚度為2.0 mm。然而，光擴散若另設有表面層時，即在基板層的一側表面上形成這表面層，就此而言，該基板層的厚度為1.0 mm，而表面層的厚度則為0.1 mm。The light diffusing plate was formed by a co-extrusion process at a temperature of 250 ° C using an extruder having a screw diameter of 135 mm and 60 mm. In the case where the light diffusing plate is composed of only one substrate layer, the thickness of the substrate layer is 2.0 mm. However, when the light diffusion is additionally provided with the surface layer, that is, the surface layer is formed on one side surface of the substrate layer, the substrate layer has a thickness of 1.0 mm and the surface layer has a thickness of 0.1 mm.
在前述各範例及比較範例之光擴散板的組成中，基板層是將表1所示的樹脂主劑與0.2重量份作為光擴散劑的矽樹脂珠粒(beads)(平均粒度：2 μm)與0.05重量份在光穩定劑中作為紫外線吸收劑的B－cap(四乙基－2,2’－(1,4－苯撐－二亞甲基)－雙丙二酸)(tetra－ethyl－2,2’－(1,4－phenylene－dimethylidene)－bismalonate)混合而構成，表面層則由表面層所用的樹脂主劑構成，或將該樹脂主劑與前述表中所載的氟樹脂或氟樹脂粒子，2重量份作為光擴散劑的矽樹脂珠粒(平均粒度：2 μm)與0.5重量份在光穩定劑中作為紫外線吸收劑的B－cap(四乙基－2,2’－(1,4－苯撐－二亞甲基)－雙丙二酸)混合而構成。In the composition of the light diffusing plate of each of the foregoing examples and comparative examples, the substrate layer is a resin main component shown in Table 1 and 0.2 part by weight of a beryllium resin (average particle size: 2 μm) as a light diffusing agent. B-cap (tetraethyl-2,2'-(1,4-phenylene-dimethylene)-bismalonic acid) as a UV absorber in 0.05 parts by weight in a light stabilizer (tetra-ethyl) -2,2'-(1,4-phenylene-dimethylidene)-bismalonate), the surface layer is composed of a resin base agent used for the surface layer, or the resin base agent and the fluororesin contained in the above table Or fluororesin particles, 2 parts by weight of ruthenium resin beads (average particle size: 2 μm) as a light diffusing agent and 0.5 parts by weight of B-cap (tetraethyl-2, 2' as a UV absorber in a light stabilizer -(1,4-Benzene-dimethylene)-bismalonic acid) is mixed and formed.
前述範例及比較範例所製成的光擴散劑，均對其進行吸水率，彎折，總透光率，霧度，發黃指數以及熱形變溫度的測量。表5到8所示者即為其結果。The light diffusing agents prepared in the foregoing examples and comparative examples were subjected to measurement of water absorption, bending, total light transmittance, haze, yellowing index, and heat deformation temperature. The results shown in Tables 5 to 8 are the results.
吸水率的測量方法是先將光擴散板裁切成10公分見方大小，接著將其在25℃的水中浸24小時。彎折的測定方式是把光擴散板安裝到20英吋大小的背光單元上，再於60℃的溫度和75%相對濕度的條件下使其靜置96小時，然後測量光擴散板向上翹曲之四個角隅與背光單元表面之間相距的距離。熱形變溫度則是依照ASTM D648標準予以測量。The water absorption rate was measured by first cutting the light diffusing plate to a size of 10 cm square, and then immersing it in water at 25 ° C for 24 hours. The bending method is performed by mounting the light diffusing plate on a 20-inch-sized backlight unit, allowing it to stand at a temperature of 60 ° C and a relative humidity of 75% for 96 hours, and then measuring the upward warpage of the light diffusing plate. The distance between the four corners and the surface of the backlight unit. The heat distortion temperature is measured in accordance with ASTM D648.
發黃指數(yellowing index)係在ASTM D1925標準所規定的條件下，採用配備FS－40 313/280螢光燈的Q－UV測試儀，於40℃的溫度照射240小時後，依ASTM D1003標準進行測量。總透光率及霧度也是依ASTM D1003標準予以測量。The yellowing index is based on the ASTM D1925 standard, using a Q-UV tester equipped with FS-40 313/280 fluorescent lamp, after 240 hours of exposure at 40 ° C, according to ASTM D1003 standard Make measurements. The total light transmittance and haze are also measured in accordance with ASTM D1003.
從前述各性質的結果可知，僅具有以聚碳酸酯樹脂及聚苯乙烯樹脂混合物作為樹脂主劑所構成之基板層的光擴散板縱然是在高溫和高濕的條件下，均可確認擁有較高的形穩性，唯一的例外是發黃指數高。As is apparent from the results of the above respective properties, the light-diffusing sheet having only the substrate layer composed of the polycarbonate resin and the polystyrene resin mixture as the resin main component can be confirmed to have a higher temperature and high humidity. High shape stability, the only exception is the high yellowing index.
從前述各性質的結果可知，具有以聚碳酸酯樹脂作為樹脂主劑所構成之基板層和在該基板層的一表面上形成表面層，或該表面層另含有氟樹脂或氟樹脂粒子的光擴散板，可確認擁有高度的形穩性。From the results of the above properties, it is understood that the substrate layer composed of a polycarbonate resin as a resin main component and a surface layer formed on one surface of the substrate layer, or the surface layer further containing a fluororesin or a fluororesin particle The diffuser plate confirms the high dimensional stability.
是以，若用聚碳酸酯樹脂作為基板層的樹脂主劑時，不論表面層所用樹脂主劑的種類，均可看出包括形穩性在內的各種光性質甚為優越。Therefore, when a polycarbonate resin is used as the resin base agent of the substrate layer, various light properties including shape stability can be seen, regardless of the type of the resin base agent used for the surface layer.
從前述各性質的結果可知，具有以聚碳酸酯樹脂及聚苯乙烯樹脂混合物作為樹脂主劑所構成之基板層和在該基板層的一表面上以PMMA樹脂作為樹脂主劑而形成表面層的光擴散板，可確認擁有優越的形穩性與抗發黃性。From the results of the above-mentioned properties, it is known that a substrate layer composed of a polycarbonate resin and a polystyrene resin mixture as a resin main component and a PMMA resin as a resin main agent on one surface of the substrate layer form a surface layer. The light diffusing plate can be confirmed to have superior shape stability and yellowing resistance.
此外，光擴散板的表面層若另含有氟樹脂或氟樹脂粒子，則與未含有氟樹脂或氟樹脂粒子的光擴散板相比，其形穩性較優。再者，增加氟樹脂或氟樹脂粒子的用量時，形穩性會變得越來越佳。Further, when the surface layer of the light diffusing plate further contains a fluororesin or a fluororesin particle, the shape stability is superior to that of a light diffusing plate which does not contain a fluororesin or a fluororesin particle. Further, when the amount of the fluororesin or the fluororesin particles is increased, the dimensional stability becomes better.
因此，如以聚碳酸酯樹脂和價格較廉的聚苯乙烯混合物作為基板層的樹脂主劑時，其形穩性相當於或優於只用聚碳酸酯樹脂作為基板層樹脂主劑者，所以，製備成本可隨之降低。Therefore, when a polycarbonate resin and a relatively inexpensive polystyrene mixture are used as the resin base agent of the substrate layer, the dimensional stability is equivalent to or superior to that of the polycarbonate resin alone as the base resin of the substrate layer. The preparation cost can be reduced accordingly.
從前述各性質的結果可知，具有以聚碳酸酯樹脂及聚苯乙烯樹脂混合物作為樹脂主劑所構成之基板層和在該基板層的一表面上以MS樹脂作為樹脂主劑而形成表面層的光擴散板，可確認擁有優越的形穩性。From the results of the above properties, it is known that a substrate layer composed of a polycarbonate resin and a polystyrene resin mixture as a resin main component and a surface layer formed by using an MS resin as a resin main component on one surface of the substrate layer The light diffusing plate can be confirmed to have superior shape stability.
因此，縱然以價格較廉的聚苯乙烯樹脂跟聚碳酸酯樹脂混合，並作為基板層的樹脂主劑，仍能展現出優越的形穩性，從而降低製備成本。Therefore, even if a relatively inexpensive polystyrene resin is mixed with a polycarbonate resin and used as a resin main component of the substrate layer, excellent shape stability can be exhibited, thereby reducing the production cost.
從前述各性質的結果可知，光擴散板的基板層如未含聚碳酸酯樹脂或聚碳酸酯樹脂及聚苯乙烯樹脂的混合物，就可確認其所有性質，包括形穩性及抗發黃性在內，均會減低。It can be seen from the results of the foregoing properties that the substrate layer of the light diffusing plate can be confirmed to have all properties including shape stability and yellowing resistance without containing a polycarbonate resin or a mixture of a polycarbonate resin and a polystyrene resin. Within, it will be reduced.
因此，由於本發明的光擴散板包括以聚碳酸酯樹脂或聚碳酸酯樹脂及聚苯乙烯樹脂混合物形成的基板層，所以具有優越的總透光率和光擴散性，尤其具有高度的耐熱性與耐吸收性，以致形穩性良好。另外，也採用在價格上比聚碳酸酯樹脂便宜的聚苯乙烯樹脂，以致降低製備成本。Therefore, since the light diffusing plate of the present invention comprises a substrate layer formed of a polycarbonate resin or a mixture of a polycarbonate resin and a polystyrene resin, it has superior total light transmittance and light diffusibility, particularly high heat resistance and Resistant to absorption, so that the shape stability is good. In addition, a polystyrene resin which is cheaper than polycarbonate resin is also used, so that the production cost is lowered.
此外，本發明的光擴散板另包括表面層，以致在長期遭光源照射時，可發揮抗發黃效果。Further, the light diffusing plate of the present invention further includes a surface layer so that an anti-yellowing effect can be exerted when it is irradiated with a light source for a long period of time.
再者，本發明的光擴散板表面層還含有氟樹脂或氟樹脂粒子，以致進一步增進形穩性，和在長期遭光源照射時可進一步減低發黃指數，從而產生性質改良的光擴散板。Further, the surface layer of the light-diffusing sheet of the present invention further contains a fluororesin or a fluororesin particle so as to further improve the shape stability, and further reduce the yellowing index when irradiated with a light source for a long period of time, thereby producing a light-diffusing sheet having improved properties.
如前所述，本發明提供一種光擴散板。由於本發明的光擴散板包括一道以聚碳酸酯樹脂作為樹脂主劑的基板層，所以因為高度的耐吸收性而具有高度的形穩性，縱然是在高溫和高濕條件下也可減低發生彎折的現象。此外，可進一步設置一表面層，或這表面層另含有氟樹脂或氟樹脂粒子，致使光擴散板具有進一步增進的形穩性，和縱然長期遭光源照射時，仍可使發黃性進一步減低。As described above, the present invention provides a light diffusing plate. Since the light diffusing plate of the present invention comprises a substrate layer using a polycarbonate resin as a main component of the resin, it has a high dimensional stability due to high absorption resistance, and can be reduced even under high temperature and high humidity conditions. The phenomenon of bending. In addition, a surface layer may be further provided, or the surface layer further contains a fluororesin or a fluororesin particle, so that the light diffusing plate has further improved shape stability, and the yellowing property is further reduced even when irradiated by the light source for a long time. .
所舉實施例僅用以例舉說明本發明而已，並非用以限制本發明，舉凡不違本發明精神所從事的種種修改、增減或取代，俱屬本發明申請專利範圍。The embodiments are intended to be illustrative only and not to limit the invention, and all modifications, additions and substitutions or substitutions may be made without departing from the spirit of the invention.
Claims (15)
Applications Claiming Priority (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020050006560A KR100635152B1 (en) | 2005-01-25 | 2005-01-25 | Light-diffusion plate |
| KR1020050106266A KR100635154B1 (en) | 2005-11-08 | 2005-11-08 | Light-diffusion plate |
| KR1020050106268A KR100750592B1 (en) | 2005-11-08 | 2005-11-08 | Light-diffusion plate |
| KR1020050121504A KR100781686B1 (en) | 2005-12-12 | 2005-12-12 | Light-diffusion plate |
| KR1020050121507A KR100781687B1 (en) | 2005-12-12 | 2005-12-12 | Light-diffusion plate |
| KR1020050121505A KR100754412B1 (en) | 2005-12-12 | 2005-12-12 | Light-diffusion plate |
| KR1020050121509A KR100765893B1 (en) | 2005-12-12 | 2005-12-12 | Light-diffusion plate |
| KR1020050121508A KR100676774B1 (en) | 2005-12-12 | 2005-12-12 | Light-diffusion plate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| TW200639519A TW200639519A (en) | 2006-11-16 |
| TWI390296B true TWI390296B (en) | 2013-03-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| TW95102897A TWI390296B (en) | 2005-01-25 | 2006-01-25 | Light-diffusion plate |
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| TW (1) | TWI390296B (en) |
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| CN109116451A (en) * | 2018-09-26 | 2019-01-01 | 张家港康得新光电材料有限公司 | A kind of diffusion barrier and preparation method |
| CN113291024A (en) * | 2021-05-19 | 2021-08-24 | 杭州赛宁板材有限公司 | Multilayer co-extrusion composite light diffusion plate and preparation method thereof |
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