TW201119839A - Production method of white film - Google Patents

Production method of white film Download PDF

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TW201119839A
TW201119839A TW99133006A TW99133006A TW201119839A TW 201119839 A TW201119839 A TW 201119839A TW 99133006 A TW99133006 A TW 99133006A TW 99133006 A TW99133006 A TW 99133006A TW 201119839 A TW201119839 A TW 201119839A
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Taiwan
Prior art keywords
film
less
resin
white film
component
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TW99133006A
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Chinese (zh)
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TWI422481B (en
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Shigetoshi Maekawa
Daisuke Ogata
Masatoshi Izawa
Takayuki Ohira
Kozo Takahashi
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Toray Industries
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/08—Mirrors
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds

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  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Laminated Bodies (AREA)

Abstract

The present invention provides a production method of the white film which is characterized in that the said film having a layer comprising a main resin ingredient and an ingredient incompatible with the said resin ingredient being heated at least one surface by a thermal energy of more than 8.5 W/cm and less than 40 W/cm per single side, while being stretched to more than 3.0 and less than 4.5 times in the film length-wise direction, and followed by stretching to more than 3 and less than 4.5 times in the film width-wise direction, by mean of the difference of circumferential speed of roll. According to this invention a white film is stably produced with no contamination in the production lines and less film fractures.

Description

201119839 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種白色薄膜之製造方法。更詳而言， 關於一種適合用作爲面光源用反射構件（反射板、及反射 器）之白色薄膜，且可使反射特性及製膜性兩者並存之白 色薄膜之製造方法。 【先前技術】 近年來，利用液晶之顯不器是大量被用作爲電腦、電 視、可攜式電話等之顯示裝置。此等液晶顯示器，由於其 本身並非爲發光體，因此設置被稱爲「背光（backnght) 」之面光源以從背面側照射光。此外，背光不僅單純地用 於照射光，而且爲因應均勻地照射整個畫面之要求而採取 被稱爲「側光型（side light-type)或直下型（direct-type )」之面光源結構。在用作爲被期望薄型·小型化的筆記 型電腦等薄型液晶顯示器用途方面，則適用側光型背光。 側光型背光是一種由側面對畫面照射光的型式之背光。 「側光型背光」是以冷陰極線管作爲照明光源而使光 從導光板之端部入射，並以導光板使光均勻地傳播*擴散 而均勻地照射整個液晶顯示器。在此照明方法中，爲有效 率地利用光，則在冷陰極線管周圍設置反射器。並且’爲 將經由導光板所擴散之光有效率地反射於液晶畫面側’則 在導光板下方設置反射板。藉此可減少來自冷陰極線管的 光之損失，使得液晶畫面更爲明亮。 -4 - 201119839 在另一方面，在例如液晶電視之大畫面應用方面，則 採用「直下型光方式」。該方式是在液晶畫面下部並列設 置冷陰極線管者，且在反射板上平行排列冷陰極線管。反 射板是使用平面狀、或經將冷陰極線管之部分成型爲半圓 凹狀者。 對使用於此等液晶畫面用之面光源的反射器或反射板 (在下文中，則總稱爲「面光源反射構件（surface light source reflecting member)」），則要求必須爲薄膜同時 要求高的反射功能。使用於面光源反射構件之薄膜是已揭 述一種使微細氣泡包含在薄膜內部，以利用在氣固界面的 光反射之薄膜等，利用包含在薄膜中的微細氣泡與基質樹 脂之折射率差之薄膜（發明專利文獻1 )。 在薄膜內部形成微細氣泡之方法，已揭述一種製造方 法係包括：在加壓下使惰性氣體包含在聚酯樹脂片之步驟 、及在常壓下加熱該含有惰性氣體之聚酯樹脂片而使其發 泡之步驟（發明專利文獻2 )。 此外’已揭示一種用於製造在內部具有非相溶性之樹 脂粒子、且加以延伸以使氣泡形成於樹脂粒子周圍之白色 薄膜之方法（發明專利文獻3 )。 在另一方面，已揭示一種爲單層且同時含有非相溶性 之樹脂粒子及具有耐光性成分之薄膜之製造方法（發明專 利文獻4至6 )。 另外，已揭示一種在含有氣泡之白色薄膜之製造方法 201119839 中，在延伸時使用紅外線加熱器來加熱之方法（發明專利 文獻7 )。 〔先前技術文獻〕 (發明專利文獻） (發明專利文獻1 )日本發明專利特開第2 0 0 2 - 4 0 2 1 4 號公報 (發明專利文獻2)日本發明專利特開第2006-249158 號公報 (發明專利文獻3)日本發明專利特開第2009-98660 號公報 (發明專利文獻4)日本發明專利特開平第8 — 48792 號公報 (發明專利文獻5 )發明專利第4306294號公報 (發明專利文獻6)日本發明專利特表第2009-516049 號公報 (發明專利文獻7)日本發明專利特開第2006-24147 1 號公報 【發明內容】 〔發明所欲解決之技術問題〕 然而，發明專利文獻2至7之技術卻有如下所述問題 〇 發明專利文獻2之技術是薄膜之薄膜化困難、不適合 使用於面光源反射構件的薄膜之生產方法。 201119839 發明專利文獻3之技術是爲提高反射率、提高耐光性 及穩定的生產性，則必須將以高濃度添加用於形成氣泡之 非相溶性成分之內層、與含有具有耐光性功能的氧化鈦之 氣泡爲少的外層加以積層。由於該外層之氧化鈦會吸收光 之一部分，因此會阻礙反射率之提高。此外，爲了積層， 則需要大規模設備，因此，在成本方面爲不佳。 發明專利文獻4至6之技術是當爲形成氣泡而加以延 伸時，則在薄膜表面也產生氣泡導致非相溶性樹脂粒子脫 落而污染生產線。此外，雖然爲提高反射率而增多氣泡之 措施是有效，但是由於比重降低，容易破裂而無法穩定地 進行製膜。 發明專利文獻7之技術是紅外線加熱器之輸出能量小 ，只有輔助使用輥來加熱薄膜之程度而已，且會在薄膜表 面形成氣泡，以致非相溶性樹脂粒子會脫落而污染生產線 〇 本發明提供一種可解決此等技術問題、且並無生產線 污染、薄膜破裂少、可進行穩定地生產之白色薄膜之製造 方法。 〔解決問題之技術方法〕 本發明係一種白色薄膜之製造方法，用於製造在內部 含有氣泡、比重爲0.55以上且1.30以下之白色薄膜，其 係包括： 將具有含有主要樹脂成分、與對該樹脂成分爲非相溶 性成分的層之薄膜’一邊將其至少一表面以每單面爲8.5 201119839 W/cm以上且40 W/cm以下之熱量加熱，一邊利用輥之周 速差而在薄膜長度方向（film length-wise direction)延伸 3.0倍以上且4.5倍以下後，再在薄膜寬度方向（film width-wise direction)延伸3倍以上且5倍以下。 〔發明之功效〕 若根據本發明之白色薄膜之製造方法，則無生產線之 污染、薄膜破裂少、可穩定地生產白色薄膜。 【實施方式】 〔本發明之最佳實施方式〕 (1 )白色薄膜 (1.1)白色薄膜之構成 根據本發明所生產之白色薄膜是在內部含有氣泡、比 重爲0.55以上且1.30以下之白色薄膜。 白色薄膜是必須在在內部含有氣泡。白色薄膜較佳爲 在內部含有氣泡的單層之薄膜、或在內部含有氣泡之層至 少構成一側的最外層之薄膜。由於在薄膜之最外層存在著 含有氣泡之層，可獲得具有高反射特性之白色薄膜。如此 之積層白色薄膜之實例是可積層含有氣泡之層與未含有氣 泡之層、或也可積層氣泡量不同的兩種以上之層。 在本發明中’在薄膜內部所含有氣泡是可爲獨立氣泡 或數個連續氣泡者。此外’氣泡形狀是並無特殊限制，爲 朝薄膜厚度方向形成許多界面，則氣泡之截面形狀較佳爲 圓狀或呈對薄膜面方向伸長的橢圓狀。 201119839 此外’氣泡之形成方法較佳爲採取將含有用於構成在 內部具有氣泡之層的主要樹脂成分（a)、與對該樹脂成 分（a )爲非相溶性成分（b )之混合物加以熔融擠出後， 至少朝一方向延伸’以使氣泡形成於內部之方法。在此所 謂「主要樹脂成分（a)」是意謂相對於在內部具有氣泡 之層整體，質量比率爲超過50 %之成分。此方法可形成微 細且扁平的氣泡、可在良好的生產性下生產高反射性能之 白色薄膜。 該方法是利用在延伸中會在主要樹脂成分（a)與非 相溶性成分（b)之界面發生剝離而形成扁平狀氣泡之方 法。因此，爲增大氣泡佔有體積、增大薄膜厚度平均界面 數以提高反射性能，則雙軸向延伸是優於單軸向延伸。 在薄膜內部有無氣泡是可以下列方法加以確認。亦即 ，使用薄片切片機切出薄膜TD方向（薄膜寬度方向）與 平行方向之截面。對截面蒸鍍鉑-鈀後，以掃描型電子顯 微鏡（在下文中，則稱爲「SEM」）且以適當的倍率（ 5 00至10000倍）觀察截面。由觀察所獲得之畫像即可確 認氣泡。 白色薄膜之厚度較佳爲30/zm以上且500/zm以下。 厚度的下限更佳爲50#m以上。厚度的上限更佳爲300// m以下。若厚度爲小於30 g m時，則有可能導致無法獲得 足夠的反射性的情況。若厚度爲大於500 時，對於用 在要求薄膜化的液晶顯示器而言，則爲太厚。另外，若白 201119839 色薄膜爲積層物的情況，則厚度是意謂積層物整體之厚度 〇 白色薄膜之比重爲0.55以上且1.30以下，更佳爲 0.55以上且0.99以下，進一步更佳爲0.55以上且0.90以 下。在此所謂「比重」是意謂白色薄膜整體之比重。若比 重爲低於0.55時，則薄膜之強度降低、使得薄膜容易斷 裂而導致生產性差，因此爲不佳。此外，在液晶顯示器之 組配作業中容易發生折皺，因此爲不佳。若比重爲超過 1.30時，由於含有氣泡所獲得之反射性將變得不足夠，因 此爲不佳。 控制白色薄膜之比重爲0.55以上且1.30以下之方法 是包括：1)增加非相溶性成分（b)之含量；2)使用樹 脂粒子作爲非相溶性成分（b ) ; 3)減小非相溶性成分（ b)之體積平均粒徑Dv;及4)將延伸倍率加以高倍率化 等。 在白色薄膜表面的凹陷之存在密度較佳爲1個/100 μ m2以下。根據本發明之發明人等之檢討，生產線會受到污 染之原因是由於粒子（非相溶性成分）從凹陷脫落且該粒 子會附著於生產設備的緣故。因此，控制薄膜表面的凹陷 之存在密度爲1個/100# m2以下，則可防止生產線之污染 。存在密度的下限爲0個/100 y m2以上。此外，爲獲得本 功效，則較佳爲控制在薄膜兩表面的凹陷之存在密度各爲 1個/100# m2以下。在本發明中，所謂的「凹陷（crater) -10- 201119839 」是意謂薄膜表面之可在倍率爲25〇〇倍之SEM照片所觀 察到的長徑爲ljtzm以上之凹狀窪孔。 控制凹陷之存在密度爲1個/100 V 以下之方法是可 採用如後所述使用高輸出功率之紅外線加熱器等，一邊對 薄膜表面供應一定熱量（一邊加熱），一邊將薄膜加以延 伸之方法。 (1.2)主要樹脂成分（a) 主要樹脂成分（a)是構成含有氣泡之層的基質樹脂 成分。主要樹脂成分（a)較佳爲聚酯樹脂（al)。所謂 的「聚酯樹脂」是二醇成分與二羧酸成分經聚縮合所獲得 之高分子。「二羧酸成分」之代表性實例是包括：對苯二 甲酸、間苯二甲酸、鄰苯二甲酸、2,6 -萘二甲酸、己二酸 、癸二酸等。另外’ 「二醇成分」之代表性實例是包括： 乙二醇、三亞甲基二醇、四亞甲基二醇、環己烷二甲醇等 。「聚酯樹脂」之具體實例是可使用聚對苯二甲酸乙二醇 酯、聚2,6-萘二甲酸乙二醇酯（聚萘二甲酸乙二醇酯）、 聚對苯二甲酸丙二醇酯、聚對苯二甲酸丁二醇酯等。 不用說，此等聚酯是可爲均聚酯或共聚合聚酯。「共 聚合成分」是可使用例如二甘醇、新戊二醇、聚伸烷基二 醇等之「二醇成分」；己二酸、癸二酸、鄰苯二甲酸、間 苯二甲酸、2,6-萘二甲酸、5-磺基間苯二甲酸鈉等之「二 羧酸成分」。 使用如上所述樹脂作爲聚酯樹脂（a 1 )，則可在一邊 -11 - 201119839 維持高無著色性、一邊製成爲薄膜時賦予髙機械強度。從 價廉且耐熱性爲優異的觀點，則更佳爲聚對苯二甲酸乙二 醇酯（PET)、聚萘二甲酸乙二醇酯（PEN)。 (1.3)非相溶性成分（b) 只要與構成基質樹脂成分之主要樹脂成分（a)爲非 相溶性者時’則非相溶性成分（b )是並無特殊限制，可 使用對基質樹脂爲非相溶性之熱塑性樹脂（b 1 )與無機粒 子（b2)中任一者。此等成分是可單獨使用或兩種以上倂 用。熱塑性樹脂（bl )與無機粒子（b2 )併用作爲非相溶 性成分（b )是更佳的模式之一。 此外，白色薄膜較佳爲具有含有聚酯樹脂（al)、及 與聚酯樹脂（al)爲非相溶性成分（b)之層，且白色薄 膜之至少一側的最外層則爲此層。經構成爲如上所述，則 可有效率地獲得含有氣泡者，因此可製成爲具有高反射特 性之白色薄膜。白色薄膜更佳爲僅由含有聚酯樹脂（al) 及非相溶性成分（b)之層所構成。另外，在白色薄膜之 表層設置未含有氣泡之層時，則有可能由於紫外線造成高 分子劣化而導致泛黃的情況，因此爲不佳。 (1 _ 3 · 1 )熱塑性樹脂（b 1 ) 在非相溶性成分（b )是使用熱塑性樹脂（b 1 )的情 況，則其樹脂是可使用結晶性、非晶性中任一者。其具體 實例是包括：可使用例如聚乙烯、聚丙烯、聚丁烯、聚甲 基戊烯、環戊二烯等之直鏈狀、分枝鏈狀或環狀之聚烯烴 -12- 201119839 系樹脂；聚（甲基）丙烯酸酯等之丙烯酸系樹脂；聚苯乙 烯；氟系樹脂等。此等非相溶性樹脂是可爲均聚物或共聚 物，也可更進一步倂用兩種以上之非相溶性樹脂。在此等 之中，由於透明性優異且具有優越的耐熱性，較佳爲使用 聚烯烴。具體而言，較佳爲結晶性樹脂是使用聚丙烯或聚 甲基戊烯等，而非晶性樹脂則使用環烯烴共聚物等。 在主要樹脂成分（a)是使用聚酯樹脂（al)、而與 聚酯樹脂（a 1 )爲非相溶性成分是使用熱塑性樹脂（b 1 ) 的情況，其結晶性樹脂之具體實例，從透明性、耐熱性的 觀點來考慮，則更佳爲使用聚甲基戊烯。聚甲基戊烯較佳 爲在分子骨架中含有80莫耳％以上、更佳爲85莫耳％以 上、特佳爲90莫耳％以上之源自4-甲基戊烯-1之衍生單 元者。此外，其他衍生單元是可例示乙烯單元、丙烯單元 、丁烯-1單元、3-甲基丁烯-1、或除了 4-甲基戊烯-1以外 之碳數爲6至12之烴等。聚甲基戊烯是可爲均聚物或共 聚物。此外，可使用組成、或熔融黏度等爲不同的數種聚 甲基戊烯，或與其他烯烴系樹脂或其他樹脂倂用。 此外，在熱塑性樹脂（b 1 )是使用非晶性樹脂的情況 ，則特別適合使用環狀烯烴共聚物樹脂。所謂的「環狀烯 烴共聚物」是由選自由環烯、雙環烯、三環烯及四環烯所 組成的族群中之至少一種環狀烯烴、與乙烯、丙烯等直鏈 烯烴所構成之共聚物。 在環狀烯烴共聚物樹脂中之「環狀烯烴」的代表性實 -13- 201119839 例是包括：雙環[2,2,1]庚-2-烯、6 -甲基雙環[2,2,1]庚-2-烯 、5,6-二甲基雙環[2,2，1]庚-2-烯、1-甲基雙環[2,2，1]庚-2-烯、6-乙基雙環[2,2，1]庚-2-烯、6-正丁基雙環U，2，l]庚-2-烯、6-異丁基雙環[2,2，1]庚_2-烯、7-甲基雙環U，2，l]庚_2_ 烯、三環[4,3,0，125]-3-癸烯、2-甲基-三環[4,3,0，125]-3-癸 烯、5-甲基·三環[4,3,0，125]-3-癸烯、三環[4,4,〇，125]-3-癸 烯、10-甲基-三環[4,4,0，125]-3-癸烯等。 此外，在環狀烯烴共聚物樹脂中之「直鏈稀烴」的代 表性實是包括：乙烯、丙烯、1-丁烯、卜戊稀、^己烯 、1_辛烯、1-癸烯、1-十二烯、1-十四烯、卜十六嫌、1-十 八烯等。 熱塑性樹脂（b 1 )在如上所述者之中’特佳爲屬於非 晶性樹脂之環狀烯烴共聚物樹脂。環狀烯烴共聚物樹脂由 於與如後所述之包含在基質的脂環式二醇或脂環式二羧酸 之相互作用而更進一步微分散，其結果則可更進一步地提 高反射特性。 熱塑性樹脂（bl )較佳爲其玻璃轉移溫度Tg爲170°C 以上，更佳爲180°C以上。經控制爲170°C以上’則在捏 合時可更微細地分散於基質樹脂中、在延伸步驟中形成氣 泡、且可更進一步抑制在熱處理步驟中之氣泡消失。上限 較佳爲2 50 °C。若超過25(TC時，則製膜時之擠出溫度將 需要升高，因此有可能導致加工性變差的情況。 特別是在熱塑性樹脂（bl)是使用環狀烯烴共聚物樹 • 14- 201119839 脂的情況，若其玻璃轉移溫度Tg爲低於 予尺寸穩定性而實施薄膜之熱處理時，則 成核劑的環狀烯烴共聚物樹脂變形的情況 可能導致以其爲核所形成之氣泡會減少或 特性降低的情況。此外，若欲維持反射特 度低溫化時，則有可能會導致薄膜之尺寸 況。 在熱塑性樹脂（bl)是使用環狀烯烴 況，若欲控制玻璃轉移溫度Tg爲在170°C 下之範圔時，則例如可採取增多環狀烯烴 烯烴成分的含量、而減少乙烯等之直鏈烯 方法。具體而言，較佳爲環狀烯烴共聚物 分爲60莫耳％以上、而乙烯等之直鏈烯烴 少於40莫耳％。更佳爲環狀烯烴成分爲 而乙烯等之直鏈烯烴成分的含量則爲少於 步更佳爲環狀烯烴成分爲80莫耳％以上、 烯烴成分的含量則爲少於20莫耳％。特佳 爲90莫耳％以上、而乙烯等之直鏈烯烴成 於1 〇莫耳％。經設定爲如此範圍，則可將 之玻璃轉移溫度Tg提高至170°C。 此外，在熱塑性樹脂（bl)是使用環 脂的情況，直鏈烯烴成分是並無特殊限制 的觀點來考慮，則較佳爲乙烯成分。 170°C，在爲賦 有可能導致作爲 。其結果，則有 消失，使得反射 性而使熱處理溫 穩定性降低的情 共聚物樹脂的情 以上且250°C以 共聚物中之環狀 烴成分的含量之 中之環狀烯烴成 成分的含量則爲 70莫耳％以上、 3 0莫耳％，進一 而乙烯等之直鏈 爲環狀烯烴成分 分的含量則爲少 環狀烯烴共聚物 狀烯烴共聚物樹 ，但是從反應性 -15- 201119839 再者，環狀烯烴成分也並無特殊限制’但是從生產性 、透明性、高T g化的觀點來考慮’則較佳爲雙環[2，2，1 ] 庚-2-烯（降冰片烯）或其衍生物。 因此，白色薄膜較佳爲具有含有聚酯樹脂（al)及非 相溶性成分（b )之層，且非相溶性成分（b )是玻璃轉移 溫度爲1 7 0 °C以上且2 5 0 °C以下之熱塑性樹脂（b 1 )。進 一步更佳爲熱塑性樹脂（b 1 )是非晶性樹脂。特佳爲熱塑 性樹脂（b 1 )是非晶性之環狀烯烴共聚物樹脂。 相對於含有氣泡之層整體，熱塑性樹脂（b 1 )之含量 較佳爲3質量％以上且25質量％以下。含量的下限更佳爲 5質量％以上。含量的上限更佳爲10質量％以下。若熱塑 性樹脂（b 1 )之含量爲少於3質量％時，則在薄膜內部無 法形成足夠的氣泡，有可能造成白色性或光反射特性變差 的情況。若熱塑性樹脂（bl)之含量爲超過25質量％時， 則薄膜之強度降低、在延伸時則有可能發生容易斷裂的情 況。經控制含量爲在3質量％以上且2 5質量％以下之範圍 ’則可顯現足夠的白色性.反射性•輕量性。 (1.3.2)無機粒子（b2) 在使用「無機粒子（b2)」作爲非相溶性成分（b) 的情況’其實例是包括：玻璃、二氧化矽、硫酸鋇、氧化 鈦、硫酸鎂、碳酸鎂、碳酸鈣、滑石等。 在主要樹脂成分（a )是使用聚酯樹脂（a丨）的情況 ’特別是從氣泡形成、白色度 '光學濃度等綜合性功效的 -16- 201119839 觀點來考慮，則在此等無機粒子之中，較佳爲使用選自由 氧化鈦、碳酸鈣及硫酸鋇所組成的族群中之至少一種以上 的無機粒子（b2 )，特佳爲氧化鈦。 相對於含有氣泡之層整體，無機粒子（b2)之含量較 佳爲5質量％以上且60質量％以下。含量的下限更佳爲1〇 質量％以上。含量的上限更佳爲20質量％以下。若無機粒 子（b2 )之含量爲少於5質量％時，則在薄膜內部無法形 成足夠的氣泡，有可能造成白色性或光反射特性變差的情 況。若無機粒子（b2)之含量爲超過60質量％時，則薄膜 之強度降低，在延伸時有可能發生容易斷裂的情況。經控 制含量爲在5質量％以上且60質量％以下之範圍，則可顯 現足夠的白色性、反射性及輕量性。 熱塑性樹脂（bl )與無機粒子（b2 )併用作爲非相溶 性成分（b)是較佳的模式之一。特佳爲白色薄膜是具有 含有聚酯樹脂（al)及非相溶性成分（b)之層，且使用 玻璃轉移溫度爲170 °C以上250 °C以下之熱塑性樹脂（bl )，以及選自由氧化鈦、碳酸鈣及硫酸鋇所組成的族群中 之至少一種以上的無機粒子（b2 )作爲非相溶性成分（b )。並且，較佳爲相對於含有氣泡之層整體，則熱塑性樹 脂（bl)之含量爲質量3%以上且25質量％以下，且相對 於含有氣泡之層整體，則無機粒子（b2)之含量爲5質量 %以上60質量％以下。 (1.4)其他添加物 -17- 201119839 含有氣泡之層的基質樹脂成分，也可混合經 脂（al)導入共聚合成分所獲得之共聚合聚酯楦 。共聚合成分之量是並無特殊限制，但是從透明 性等的觀點、及在下文篇段所述非晶化的觀點來 二羧酸成分及二醇成分較佳爲相對於各成分皆爲 以上且70莫耳％以下、更佳爲10莫耳％以上且 以下。 此外’共聚合樹脂（c)較佳爲使用經共聚 非晶性之聚酯。其實例是包括：二醇成分之主成 式二醇之共聚合聚酯樹脂、或酸成分爲脂環式二 聚合聚酯樹脂等。特別是從透明性、成型性的觀 所述非相溶性樹脂之微分散化功效的觀點來考慮 用將二醇成分與脂環式二醇之一種的環己烷二甲 聚合所獲得之非晶性聚酯。此時，從非晶化的觀 ’則較佳爲設定共聚合聚酯樹脂（c)之二醇成 烷二甲醇成分爲30莫耳％以上。 經在含有氣泡之層的基質樹脂中導入共聚合 (c)，在使用作爲熱塑性樹脂（bl)的環狀烯 樹脂作爲非相溶性成分（b )的情況，由於共聚 脂（c )之環式脂肪族烴部分、與環狀烯烴共聚 環狀烯烴部分的相互作用’環狀烯烴共聚物樹脂 分散於基質樹脂中，其結果，即可達成高反射性 性、輕量性。此外，由於添加共聚合聚酯樹脂 在聚酯樹 ί 脂（c ) 性、成型 考慮，則 1莫耳％ 4 0莫耳％ 合而成爲 分爲脂環 羧酸之共 點或如後 ，則可使 醇進行共 點來考慮 分的環己 聚酯樹脂 烴共聚物 合聚酯樹 物樹脂之 則可以微 、高白色 (c )，因 -18- 201119839 此可提高延伸性或製膜性。 相對於100質量％之構成含有氣泡之層的基質之全部 樹脂，共聚合聚酯（C )之含量較佳爲1質量％以上且少於 50質量％。含量的下限更佳爲1.5質量％以上。含量的上 限更佳爲40質量％以下、特佳爲35質量％以下。若共聚 合聚酯（c )之含量爲少於1質量％時，則有可能導致將熱 塑性樹脂（bl)微分散化於基質中將會變得困難的情況。 若共聚合聚酯（c )之含量爲50質量％以上時’則耐熱性 降低，以致有可能導致爲賦予尺寸穩定性而實施薄膜之熱 處理時，基質樹脂會軟化，其結果，則有可能造成氣泡減 少或消失、反射特性降低的情況。此外，若欲維持反射特 性而將熱處理溫度加以低溫化時，則有可能導致薄膜之尺 寸穩定性降低的情況。經控制共聚合聚酯（c )之含量爲 在1質量％以上且少於50質量％之範圍，則可一邊充分地 發揮如上所述非相溶性成分之分散功效，一邊維持薄膜製 膜性或機械特性。其結果，則可使得高反射率與尺寸穩定 性兩者並存。 爲使熱塑性樹脂（bl)更微分散於含有氣泡之層的基 質樹脂中，較佳爲在基質樹脂中，除了如前所述聚酯樹脂 (al)及共聚合聚酯樹脂（c)以外，更進一步含有分散 劑（d )。若含有分散劑（d )時，則可使得熱塑性樹脂（ b 1 )之分散徑變得更小。其結果，則可將因延伸所形成的 扁平氣泡更微細化，因此，就結果而言，則可提高薄膜之 -19- 201119839 白色性、反射性及輕量性。 分散劑（d)之種類是並無特殊限制，可使用 基或環氧基等極性基、或具有與聚酯反應性之官能 烴系之聚合物或共聚物、二甘醇、聚伸烷基二醇、 性劑及熱接著性樹脂等。不用說，此等是可單獨使 或其兩種以上併用。其中’特佳爲含有聚酯成分與 基二醇成分之聚酯-聚伸烷基二醇共聚物（dl)。 在此情況下，聚酯成分較佳爲由碳數爲2以上 下之脂肪族二醇成分、與由對苯二甲酸及/或間苯 成分所構成之聚酯成分。此外’聚伸烷基二醇成分 聚乙二醇、聚丙二醇、聚四亞甲基二醇等之成分。 特佳的組合是包括：聚酯成分是使用聚對苯二 二醇酯或聚對苯二甲酸丁二醇酯’而聚伸烷基二醇 使用聚乙二醇或聚四亞甲基二醇之組合。其中’特 酯成分是使用聚對苯二甲酸丁二醇酯’而聚伸烷基 分是使用聚四亞甲基二醇之組合；或聚酯成分是使 苯二甲酸乙二醇酯，而聚伸烷基二醇成分是使用聚 之組合。 相對於100質量％構成基質之全部樹脂’分散； 之含量較佳爲0.1質量％以上且30質量％以下。含 限更佳爲1質量％以上，特佳爲1.5質量％以上。含 限更佳爲25質量％以下，特佳爲20質量％以下° 爲少於0.1重量％時，則有可能導致微細化氣泡之 具有羧 基的烯 界面活 用一種 聚伸烷 且6以 二甲酸 較佳爲 甲酸乙 成分是 佳爲聚 二醇成 用聚對 乙二醇 量的下 量的上 若含量 功效變 -20- 201119839 小的情況。若含量爲多於3 0重量％時，則耐熱性降低，有 可能導致爲賦予尺寸穩定性而實施薄膜之熱處理時，則基 質軟化，其結果，使得氣泡減少或消失、以致反射特性降 低的情況。此外，若欲維持反射特性而將熱處理溫度加以 低溫化時，則有可能導致薄膜之尺寸穩定性降低的情況。 此外，有可能造成生產穩定性降低或成本上升等問題。經 控制分散劑（d )之含量爲在〇.1質量％以上且30質量％以 下之範圍，則可在充分地發揮熱塑性樹脂（bl)之分散功 效下，維持薄膜製膜性或機械特性，結果可使得高反射率 與尺寸穩定性兩者並存。 此外，因應需要可對白色薄膜摻合不致於損及本發明 功效之適量的添加劑，例如耐熱穩定劑、抗氧化穩定劑、 紫外線吸收劑、紫外線穩定劑、有機系之潤滑劑、有機系 微粒子、塡充劑、成核劑、染料、分散劑、偶合劑等。 (2 )薄膜特性 白色薄膜之全光線透射率較佳爲1.5%以下、更佳爲 1.2%以下、進一步更佳爲1.0%以下。另外，在此所謂「全 光線透射率j是意謂根據nS-K7361-l( 1997年版）之準 則所測定之値。經控制全光線透射率爲1 · 5 %以下，則可 抑制朝背面之漏光。其結果，可製得白色性、反射特性優 異的白色薄膜。特別是在用作爲液晶顯示裝置用的情況， 則可獲得高輝度提高功效。 白色薄膜之相對反射率較佳爲100%以上、更佳爲 -21 - 201119839 100.5%以上、進一步更佳爲101 %以上。上限是並無特殊 限制者’但是在實務應用上則爲120%以下。經控制相對 反射率爲1 0 0 %以上，則可製成白色性、反射特性優異的 白色薄膜。特別是在用作爲液晶顯示裝置用的情況，則可 獲得高輝度提高功效。 爲將白色薄膜之全光線透射率或相對反射率調整爲在 如上所述之範圍，則可藉由1 )控制薄膜內部之樹脂粒子 的分散徑、密度爲在如前所述之範圍；2)增加薄膜之厚 度等措施來獲得。 (3 )製造方法 在下文中，則就本發明之白色薄膜之製造方法加以說 明，但是除了延伸方法以外，則並不受限於此等。 因應需要可將含有聚酯樹脂（al)與非相溶性成分（ b)之混合物充分地真空乾燥後，供應至配備有擠壓機（ 主擠壓機）之製膜裝置之經加熱的擠壓機》非相溶性成分 (b)之添加是可使用經預先均勻地熔融捏合而加以摻合 所獲得之母料切粒，或也可直接供應至捏合擠壓機等。由 於可促進非相溶性成分（b)的分散，較佳爲使用預先將 含有聚酯樹脂（a 1 )與非相溶性成分（b )之混合物均勻 地熔融捏合所獲得之母料切粒。201119839 VI. Description of the Invention: [Technical Field to Which the Invention Is Ascribed] The present invention relates to a method of producing a white film. More specifically, the present invention relates to a method for producing a white film which is suitable as a white film for a surface light source reflecting member (reflector and reflector) and which can coexist both in reflection property and film formability. [Prior Art] In recent years, display devices using liquid crystals have been widely used as display devices for computers, televisions, portable telephones, and the like. Since these liquid crystal displays are not illuminants themselves, a surface light source called "backnght" is provided to illuminate light from the back side. Further, the backlight is not only used for illuminating light, but also has a surface light source structure called "side light-type or direct-type" in response to the requirement of uniformly illuminating the entire screen. In the use of a thin liquid crystal display such as a notebook computer which is expected to be thin and miniaturized, a sidelight type backlight is applied. The edge-lit backlight is a type of backlight that illuminates the screen from the side. The "sidelight type backlight" uses a cold cathode tube as an illumination source to cause light to enter from the end of the light guide plate, and uniformly spreads the light by the light guide plate to uniformly illuminate the entire liquid crystal display. In this illumination method, in order to utilize light efficiently, a reflector is disposed around the cold cathode conduit. Further, in order to efficiently reflect the light diffused through the light guide plate to the liquid crystal screen side, a reflection plate is provided below the light guide plate. Thereby, the loss of light from the cold cathode conduit can be reduced, making the liquid crystal picture brighter. -4 - 201119839 On the other hand, in the case of large-screen applications such as LCD TVs, the "direct-light mode" is adopted. In this method, cold cathode conduits are arranged side by side in the lower portion of the liquid crystal screen, and cold cathode conduits are arranged in parallel on the reflector. The reflector is formed in a planar shape or formed by forming a portion of the cold cathode conduit into a semicircular concave shape. A reflector or a reflection plate (hereinafter, collectively referred to as a "surface light source reflecting member") for a surface light source for such a liquid crystal screen is required to have a high reflection function at the same time as the film. . The film used for the surface light source reflecting member has been disclosed as a film which allows fine bubbles to be contained inside the film to utilize light reflection at the gas-solid interface, and the refractive index difference between the fine bubbles contained in the film and the matrix resin. Film (Invention Patent Document 1). A method of forming fine bubbles inside a film, and a manufacturing method comprising: a step of allowing an inert gas to be contained in a polyester resin sheet under pressure, and heating the inert resin-containing polyester resin sheet under normal pressure The step of foaming it (Patent Document 2). Further, a method for producing a white film having incompatible resin particles therein and extending to form bubbles around the resin particles has been disclosed (Patent Document 3). On the other hand, a method for producing a film which is a single layer and which contains both incompatible resin particles and a light-resistant component has been disclosed (Patent Documents 4 to 6). Further, a method of heating using an infrared heater during stretching (Invention Patent Document 7) in the method of producing a white film containing bubbles is disclosed in 201119839. [PRIOR ART DOCUMENT] (Invention Patent Document) Japanese Patent Laid-Open Publication No. 2000-249158 (Japanese Patent Publication No. 2006-249158) Japanese Laid-Open Patent Publication No. 2009-98660 (Invention Patent Document 4) Japanese Laid-Open Patent Publication No. Hei 8-48792 (Invention Patent Document 5) Patent No. 4306294 (Invention Patent Japanese Patent Application Publication No. 2009-516049 (Invention Patent Document 7) Japanese Laid-Open Patent Publication No. 2006-24147 No. (Convention) [Technical Problem to be Solved by the Invention] However, the patent document of the invention The technique of 2 to 7 has the following problems. The technique of Patent Document 2 is a method for producing a film which is difficult to form a film and which is not suitable for use in a surface light source reflecting member. 201119839 The technique of the invention patent document 3 is that in order to improve reflectance, improve light resistance, and stable productivity, it is necessary to add an inner layer for forming a non-coherent component of a bubble at a high concentration, and an oxidation containing a function of light resistance. The bubbles of titanium are laminated with a small outer layer. Since the titanium oxide of the outer layer absorbs a part of the light, the increase in reflectance is hindered. In addition, in order to laminate, large-scale equipment is required, and therefore, it is not preferable in terms of cost. The techniques of Patent Documents 4 to 6 are such that when the bubbles are formed to be expanded, bubbles are also generated on the surface of the film to cause the non-compatible resin particles to fall off to contaminate the production line. Further, although the measure for increasing the bubble to increase the reflectance is effective, since the specific gravity is lowered, the film is easily broken and the film formation cannot be performed stably. The technique of the invention patent document 7 is that the output energy of the infrared heater is small, and only the extent to which the roller is used to heat the film is assisted, and bubbles are formed on the surface of the film, so that the non-compatible resin particles fall off and contaminate the production line. The present invention provides a A method for producing such a white film that can solve such technical problems and has no line contamination, thin film cracking, and stable production. [Technical method for solving the problem] The present invention relates to a method for producing a white film, which is used for producing a white film having bubbles inside and having a specific gravity of 0.55 or more and 1.30 or less, which comprises: having a main resin component, and The film of the layer in which the resin component is an incompatible component is heated at a temperature of 8.5 201119839 W/cm or more and 40 W/cm or less on at least one surface thereof, and the film length is used in the film length. After the film length-wise direction is extended by 3.0 times or more and 4.5 times or less, it is extended by 3 times or more and 5 times or less in the film width-wise direction. [Effect of the Invention] According to the method for producing a white film of the present invention, there is no contamination of the production line, and the film is less broken, and a white film can be stably produced. [Embodiment] [Best Mode for Carrying Out the Invention] (1) White film (1.1) Configuration of white film The white film produced according to the present invention is a white film containing bubbles inside and having a specific gravity of 0.55 or more and 1.30 or less. The white film must contain bubbles inside. The white film is preferably a film of a single layer containing bubbles inside, or a film containing a layer of bubbles inside at least the outermost layer constituting one side. Since a layer containing bubbles is present on the outermost layer of the film, a white film having high reflection characteristics can be obtained. Examples of such a laminated white film are two or more layers in which a layer containing bubbles and a layer not containing bubbles or a layer of bubbles may be different. In the present invention, the bubble contained inside the film may be a closed cell or a plurality of continuous cells. Further, the shape of the bubble is not particularly limited, and a plurality of interfaces are formed in the thickness direction of the film, and the cross-sectional shape of the bubble is preferably a circular shape or an elliptical shape elongated in the direction of the film surface. Further, in the method of forming a bubble, it is preferable to melt a mixture containing a main resin component (a) for constituting a layer having bubbles therein and a mixture of a non-compatible component (b) for the resin component (a). After extrusion, a method of extending at least in one direction to form bubbles inside. The term "main resin component (a)" as used herein means a component having a mass ratio of more than 50% with respect to the entire layer having bubbles inside. This method forms fine and flat bubbles, and produces a white film with high reflectivity under good productivity. This method is a method in which a flat bubble is formed by peeling off at the interface between the main resin component (a) and the incompatible component (b) during stretching. Therefore, in order to increase the bubble occupying volume and increase the average thickness of the film thickness to improve the reflection performance, the biaxial stretching is superior to the uniaxial stretching. The presence or absence of air bubbles inside the film can be confirmed by the following methods. Namely, a section of the film in the TD direction (film width direction) and the parallel direction was cut out using a microtome. After the platinum-palladium was vapor-deposited from the cross section, the cross section was observed with a scanning electron microscope (hereinafter referred to as "SEM") at an appropriate magnification (500 to 10,000 times). The bubbles are confirmed by observing the images obtained. The thickness of the white film is preferably 30/zm or more and 500/zm or less. The lower limit of the thickness is more preferably 50#m or more. The upper limit of the thickness is more preferably 300 / / m or less. If the thickness is less than 30 gm, there is a possibility that sufficient reflectivity cannot be obtained. If the thickness is more than 500, it is too thick for a liquid crystal display which is required to be thinned. Further, in the case where the white film 201119839 is a laminate, the thickness means the thickness of the entire laminate, and the specific gravity of the white film is 0.55 or more and 1.30 or less, more preferably 0.55 or more and 0.99 or less, still more preferably 0.55 or more. And below 0.90. The term "specific gravity" as used herein means the proportion of the overall white film. When the specific gravity is less than 0.55, the strength of the film is lowered, the film is easily broken, and the productivity is poor, so that it is not preferable. Further, wrinkles are liable to occur in the assembly operation of the liquid crystal display, which is not preferable. If the specific gravity is more than 1.30, the reflectance obtained by containing bubbles will become insufficient, and thus it is not preferable. The method of controlling the white film to have a specific gravity of 0.55 or more and 1.30 or less includes: 1) increasing the content of the incompatible component (b); 2) using the resin particles as the incompatible component (b); 3) reducing the incompatibility The volume average particle diameter Dv of the component (b); and 4) the magnification ratio is increased to a high magnification. The density of the depressions on the surface of the white film is preferably 1/100 μm 2 or less. According to the review by the inventors of the present invention, the reason why the production line is contaminated is that particles (incompatible components) fall off from the depressions and the particles adhere to the production equipment. Therefore, if the density of the depressions on the surface of the control film is 1/100# m2 or less, contamination of the production line can be prevented. The lower limit of the density of existence is 0/100 y m2 or more. Further, in order to obtain the present effect, it is preferable to control the density of the depressions on both surfaces of the film to be 1/100# m2 or less. In the present invention, the term "crater -10- 201119839" means a concave pupil having a long diameter of ljtzm or more as observed on an SEM photograph having a magnification of 25 薄膜 on the surface of the film. The method of controlling the presence density of the depressions to be 1/100 V or less is a method of extending the film while supplying a certain amount of heat (heating) to the surface of the film by using an infrared heater of a high output power as described later. . (1.2) Main resin component (a) The main resin component (a) is a matrix resin component constituting a layer containing bubbles. The main resin component (a) is preferably a polyester resin (al). The "polyester resin" is a polymer obtained by polycondensation of a diol component and a dicarboxylic acid component. Representative examples of the "dicarboxylic acid component" include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid and the like. Further, representative examples of the "diol component" include: ethylene glycol, trimethylene glycol, tetramethylene glycol, cyclohexane dimethanol, and the like. Specific examples of "polyester resin" are polyethylene terephthalate, polyethylene-2,6-naphthalate (polyethylene naphthalate), polytrimethylene terephthalate. Ester, polybutylene terephthalate, and the like. Needless to say, these polyesters may be homopolyester or copolymerized polyester. The "copolymerization component" is a "diol component" such as diethylene glycol, neopentyl glycol or polyalkylene glycol; adipic acid, sebacic acid, phthalic acid, isophthalic acid, A "dicarboxylic acid component" such as 2,6-naphthalenedicarboxylic acid or sodium 5-sulfoisophthalate. When the resin as described above is used as the polyester resin (a 1 ), the mechanical strength can be imparted when the film is formed into a film while maintaining high coloring resistance on one side -11 - 201119839. From the viewpoint of being inexpensive and excellent in heat resistance, polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is more preferable. (1.3) The incompatible component (b) is not particularly limited as long as it is incompatible with the main resin component (a) constituting the matrix resin component. The non-compatible component (b) is not particularly limited, and the matrix resin may be used. Any one of the incompatible thermoplastic resin (b 1 ) and the inorganic particles (b2). These components may be used singly or in combination of two or more. It is one of the more preferable modes to use the thermoplastic resin (b1) together with the inorganic particles (b2) as the incompatible component (b). Further, the white film preferably has a layer containing a polyester resin (al) and an incompatible component (b) with the polyester resin (al), and the outermost layer of at least one side of the white film is the layer. By configuring as described above, it is possible to efficiently obtain a bubble-containing one, and therefore it can be made into a white film having high reflection characteristics. More preferably, the white film is composed of a layer containing a polyester resin (al) and an incompatible component (b). Further, when a layer containing no bubbles is provided on the surface layer of the white film, yellowing may occur due to deterioration of high molecular weight due to ultraviolet rays, which is not preferable. (1 _ 3 · 1) The thermoplastic resin (b 1 ) When the non-compatible component (b) is a thermoplastic resin (b 1 ), the resin may be either crystalline or amorphous. Specific examples thereof include: a linear, branched chain or cyclic polyolefin such as polyethylene, polypropylene, polybutene, polymethylpentene, cyclopentadiene, or the like, which can be used. Resin; acrylic resin such as poly(meth)acrylate; polystyrene; fluorine-based resin. These non-compatible resins may be homopolymers or copolymers, or two or more kinds of incompatible resins may be further used. Among these, polyolefin is preferably used because it is excellent in transparency and has excellent heat resistance. Specifically, it is preferable to use polypropylene or polymethylpentene as the crystalline resin, and a cycloolefin copolymer or the like as the amorphous resin. In the case where the main resin component (a) is a polyester resin (al) and the polyester resin (a1) is a non-compatible component, a thermoplastic resin (b1) is used, and a specific example of the crystalline resin thereof is used. From the viewpoint of transparency and heat resistance, it is more preferable to use polymethylpentene. The polymethylpentene is preferably a derivative derived from 4-methylpentene-1 in a molecular skeleton of 80 mol% or more, more preferably 85 mol% or more, particularly preferably 90 mol% or more. By. Further, other derivatization units are exemplified by an ethylene unit, a propylene unit, a butene-1 unit, a 3-methylbutene-1, or a hydrocarbon having a carbon number of 6 to 12 other than 4-methylpentene-1. . Polymethylpentene can be a homopolymer or a copolymer. Further, it is possible to use a plurality of kinds of polymethylpentenes having different compositions or melt viscosities, or to use them with other olefin resins or other resins. Further, in the case where the thermoplastic resin (b 1 ) is an amorphous resin, a cyclic olefin copolymer resin is particularly preferably used. The "cyclic olefin copolymer" is a copolymer composed of at least one cyclic olefin selected from the group consisting of a cyclic olefin, a bicycloolefin, a tricycloolefin, and a tetracycloolefin, and a linear olefin such as ethylene or propylene. Things. Representative examples of "cyclic olefins" in cyclic olefin copolymer resins are: - bicyclo[2,2,1]hept-2-ene, 6-methylbicyclo[2,2, 1]hept-2-ene, 5,6-dimethylbicyclo[2,2,1]hept-2-ene, 1-methylbicyclo[2,2,1]hept-2-ene, 6-B Bicyclo[2,2,1]hept-2-ene, 6-n-butylbicyclo-U,2,l]hept-2-ene, 6-isobutylbicyclo[2,2,1]heptan-2- Alkene, 7-methylbicyclo-U, 2,l]hept-2-ene, tricyclo[4,3,0,125]-3-decene, 2-methyl-tricyclo[4,3,0,125 ]-3-decene, 5-methyl-tricyclo[4,3,0,125]-3-decene, tricyclo[4,4,fluorene,125]-3-decene, 10-methyl - Tricyclo[4,4,0,125]-3-decene, and the like. In addition, the representative of "linear aliphatic hydrocarbon" in the cyclic olefin copolymer resin includes: ethylene, propylene, 1-butene, pentylene, hexene, 1-octene, 1-decene. , 1-dodecene, 1-tetradecene, hexapod, 1-octadecene, and the like. The thermoplastic resin (b 1 ) is particularly preferably a cyclic olefin copolymer resin belonging to an amorphous resin among those described above. The cyclic olefin copolymer resin is further finely dispersed by interaction with an alicyclic diol or an alicyclic dicarboxylic acid contained in the matrix as described later, and as a result, the reflection property can be further improved. The thermoplastic resin (b1) preferably has a glass transition temperature Tg of 170 ° C or more, more preferably 180 ° C or more. When it is controlled to be 170 ° C or more, it is more finely dispersed in the matrix resin at the time of kneading, bubbles are formed in the stretching step, and the disappearance of the bubbles in the heat treatment step can be further suppressed. The upper limit is preferably 2 50 °C. If it exceeds 25 (TC), the extrusion temperature at the time of film formation will need to be increased, so that the workability may be deteriorated. Especially in the case where the thermoplastic resin (bl) is a cyclic olefin copolymer tree. 201119839 In the case of fat, if the glass transition temperature Tg is lower than the pre-size stability and the heat treatment of the film is performed, the deformation of the cyclic olefin copolymer resin of the nucleating agent may cause the bubble formed by the core to be formed. In the case of reduction or decrease in characteristics, in addition, if the temperature of the reflection is to be lowered, the film may be in a state of being used. In the case where the thermoplastic resin (bl) is a cyclic olefin, the glass transition temperature Tg is controlled. At a temperature of 170 ° C, for example, a method of increasing the content of the cyclic olefin olefin component and reducing the linear olefin such as ethylene can be employed. Specifically, the cyclic olefin copolymer is preferably divided into 60 moles. % or more, and a linear olefin such as ethylene is less than 40 mol%. More preferably, the cyclic olefin component is a content of a linear olefin component such as ethylene, and more preferably less than a step. ear% The content of the upper olefin component is less than 20 mol%, particularly preferably 90 mol% or more, and the linear olefin of ethylene or the like is 1 mol%. When set to such a range, the glass can be used. Further, in the case where the thermoplastic resin (bl) is a cycloaliphatic resin, the linear olefin component is not particularly limited, and it is preferably an ethylene component. 170 ° C, It is possible to cause a problem, and as a result, there is a ring of the copolymer resin in which the heat resistance is lowered and the temperature stability of the heat treatment is lowered, and the content of the cyclic hydrocarbon component in the copolymer at 250 ° C is included. The content of the olefin-forming component is 70 mol% or more and 30 mol%. Further, the content of the linear olefin component such as ethylene is a small cyclic olefin copolymer olefin copolymer tree, but From the reactivity -15 - 201119839 In addition, the cyclic olefin component is not particularly limited 'but from the viewpoint of productivity, transparency, and high T g ', it is preferably bicyclo [2, 2, 1 ] g 2-ene (norbornene) or its derivatives Therefore, the white film preferably has a layer containing a polyester resin (al) and an incompatible component (b), and the incompatible component (b) has a glass transition temperature of 170 ° C or more and 2 50 The thermoplastic resin (b 1 ) is at most C C. Further preferably, the thermoplastic resin ( b 1 ) is an amorphous resin. Particularly preferably, the thermoplastic resin (b 1 ) is an amorphous cyclic olefin copolymer resin. The content of the thermoplastic resin (b 1 ) is preferably 3% by mass or more and 25% by mass or less, and the lower limit of the content is more preferably 5% by mass or more. The upper limit of the content is more preferably 10% by mass or less. When the content of (b 1 ) is less than 3% by mass, sufficient bubbles cannot be formed inside the film, and whiteness or light reflection characteristics may be deteriorated. When the content of the thermoplastic resin (b1) is more than 25% by mass, the strength of the film is lowered, and when it is stretched, the film may be easily broken. When the controlled content is in the range of 3% by mass or more and 25 % by mass or less, sufficient whiteness, reflectivity, and lightness can be exhibited. (1.3.2) Inorganic particles (b2) When "inorganic particles (b2)" are used as the incompatible component (b), examples include: glass, ceria, barium sulfate, titanium oxide, magnesium sulfate, Magnesium carbonate, calcium carbonate, talc, and the like. In the case where the main resin component (a) is a polyester resin (a), in particular, from the viewpoint of the comprehensive effects such as bubble formation and whiteness 'optical density, the inorganic particles are considered. In particular, at least one or more inorganic particles (b2) selected from the group consisting of titanium oxide, calcium carbonate and barium sulfate are used, and particularly preferably titanium oxide. The content of the inorganic particles (b2) is preferably 5% by mass or more and 60% by mass or less based on the entire layer containing the bubbles. The lower limit of the content is more preferably 1% by mass or more. The upper limit of the content is more preferably 20% by mass or less. When the content of the inorganic particles (b2) is less than 5% by mass, sufficient bubbles cannot be formed inside the film, and whiteness or light reflection characteristics may be deteriorated. When the content of the inorganic particles (b2) is more than 60% by mass, the strength of the film is lowered, and the film may be easily broken during stretching. When the controlled content is in the range of 5% by mass or more and 60% by mass or less, sufficient whiteness, reflectivity, and lightness can be exhibited. It is one of preferable modes to use the thermoplastic resin (b1) together with the inorganic particles (b2) as the incompatible component (b). Particularly preferably, the white film is a layer having a layer containing a polyester resin (al) and an incompatible component (b), and a thermoplastic resin (bl) having a glass transition temperature of 170 ° C or more and 250 ° C or less, and is selected from oxidation. At least one or more inorganic particles (b2) of the group consisting of titanium, calcium carbonate and barium sulfate are used as the incompatible component (b). Further, it is preferable that the content of the thermoplastic resin (b1) is 3% or more and 25% by mass or less based on the entire layer containing the bubbles, and the content of the inorganic particles (b2) is based on the entire layer containing the bubbles. 5 mass% or more and 60 mass% or less. (1.4) Other additives -17- 201119839 The matrix resin component of the layer containing bubbles may also be a copolymerized polyester oxime obtained by introducing a copolymer (al) into a copolymerization component. The amount of the copolymerization component is not particularly limited. However, from the viewpoint of transparency and the like, and the viewpoint of amorphization described in the following paragraph, the dicarboxylic acid component and the diol component are preferably the same as each component. And 70 mol% or less, more preferably 10 mol% or more and less. Further, the copolymerized resin (c) is preferably a copolymerized amorphous polyester. Examples thereof include a copolymerized polyester resin comprising a main form of a diol component, or an alicyclic dipolymerized polyester resin. In particular, from the viewpoint of the microdispersion effect of the non-compatible resin in terms of transparency and moldability, amorphous obtained by polymerizing cyclohexane dimethyl which is a diol component and an alicyclic diol is considered. Polyester. In this case, it is preferable that the diol-forming dimethanol component of the copolymerized polyester resin (c) is 30 mol% or more from the viewpoint of amorphization. The copolymerization (c) is introduced into the matrix resin containing the layer of the bubble, and the cyclic olefin resin as the thermoplastic resin (bl) is used as the incompatible component (b), because of the cyclic form of the copolymerized lipid (c) The interaction between the aliphatic hydrocarbon moiety and the cyclic olefin copolymerized cyclic olefin moiety 'the cyclic olefin copolymer resin is dispersed in the matrix resin, and as a result, high reflectivity and light weight can be achieved. In addition, since the addition of the copolymerized polyester resin is considered to be the co-point of the alicyclic carboxylic acid or the latter, in the case of the polyester resin (c) property and molding considerations, it is 1 mol%. The cyclohexene polyester resin hydrocarbon copolymer polyester resin which allows the alcohol to be co-pointed can be slightly and highly white (c), and the elongation or film forming property can be improved by -18-201119839. The content of the copolymerized polyester (C) is preferably 1% by mass or more and less than 50% by mass based on 100% by mass of the total of the resins constituting the layer containing the bubbles. The lower limit of the content is more preferably 1.5% by mass or more. The upper limit of the content is more preferably 40% by mass or less, particularly preferably 35% by mass or less. When the content of the copolymerized polyester (c) is less than 1% by mass, there is a possibility that it may become difficult to finely disperse the thermoplastic resin (bl) in the matrix. When the content of the copolymerized polyester (c) is 50% by mass or more, the heat resistance is lowered, so that the matrix resin may be softened when the film is heat-treated for imparting dimensional stability, and as a result, it may be caused. The case where the bubble is reduced or disappeared and the reflection characteristics are lowered. Further, if the heat treatment temperature is lowered by maintaining the reflection characteristics, the dimensional stability of the film may be lowered. When the content of the control copolymerized polyester (c) is in the range of 1% by mass or more and less than 50% by mass, the film forming property can be maintained while sufficiently exhibiting the dispersion efficiency of the incompatible component as described above or Mechanical properties. As a result, both high reflectance and dimensional stability can coexist. In order to make the thermoplastic resin (b1) more slightly dispersed in the matrix resin containing the layer of the bubble, it is preferably in the matrix resin, except for the polyester resin (al) and the copolymerized polyester resin (c) as described above. Further containing a dispersing agent (d). When the dispersing agent (d) is contained, the dispersion diameter of the thermoplastic resin (b 1 ) can be made smaller. As a result, the flat bubbles formed by the stretching can be made finer, and as a result, the whiteness, reflectivity, and lightness of the film -19-201119839 can be improved. The type of the dispersing agent (d) is not particularly limited, and a polar group such as a base or an epoxy group, or a polymer or copolymer having a functional hydrocarbon group reactive with a polyester, diethylene glycol or a polyalkylene group can be used. A diol, a property agent, and a thermal adhesive resin. Needless to say, these may be used alone or in combination of two or more. Among them, a polyester-polyalkylene glycol copolymer (dl) containing a polyester component and a base diol component is particularly preferred. In this case, the polyester component is preferably an aliphatic diol component having a carbon number of 2 or more and a polyester component composed of terephthalic acid and/or an isophthalic component. Further, the polyalkylene glycol component is a component of polyethylene glycol, polypropylene glycol, polytetramethylene glycol or the like. A particularly preferred combination includes: the polyester component is a poly(p-phenylene terephthalate or polybutylene terephthalate) and the polyalkylene glycol is a polyethylene glycol or a polytetramethylene glycol. The combination. Wherein the 'polyester component is polybutylene terephthalate' and the polyalkylene group is a combination of polytetramethylene glycol; or the polyester component is ethylene phthalate. The polyalkylene glycol component is a combination of poly. The content of all the resin constituting the matrix is 100% by mass. The content of the resin is preferably 0.1% by mass or more and 30% by mass or less. The content is more preferably 1% by mass or more, and particularly preferably 1.5% by mass or more. More preferably, the content of the content is 25% by mass or less, particularly preferably 20% by mass or less. When the amount is less than 0.1% by weight, the olefin having a carboxyl group in the micronized bubbles may be a kind of polyalkylene and 6 or less. Jiawei formic acid B component is better than the amount of poly-glycol used in the amount of poly-glycol in the amount of the upper dose of -20-201119839 small. When the content is more than 30% by weight, the heat resistance is lowered, and when the heat treatment of the film is performed to impart dimensional stability, the matrix is softened, and as a result, the bubbles are reduced or disappeared, so that the reflection characteristics are lowered. . Further, if the heat treatment temperature is lowered by maintaining the reflection characteristics, the dimensional stability of the film may be lowered. In addition, there are problems such as reduced production stability or increased costs. When the content of the controlled dispersant (d) is in the range of 0.1% by mass or more and 30% by mass or less, the film forming property or mechanical properties of the film can be maintained under the effect of sufficiently exhibiting the dispersion effect of the thermoplastic resin (bl). As a result, both high reflectance and dimensional stability can coexist. In addition, suitable amounts of additives which do not impair the efficacy of the present invention, such as heat stabilizers, oxidation stabilizers, ultraviolet absorbers, ultraviolet stabilizers, organic lubricants, organic fine particles, may be blended as needed. A chelating agent, a nucleating agent, a dye, a dispersing agent, a coupling agent, and the like. (2) Film characteristics The total light transmittance of the white film is preferably 1.5% or less, more preferably 1.2% or less, still more preferably 1.0% or less. In addition, the term "total light transmittance j" means 値 measured according to the criteria of nS-K7361-l (1997 edition). The controlled total light transmittance is 1 · 5 % or less, and the back surface can be suppressed. As a result, it is possible to obtain a white film excellent in whiteness and reflection characteristics, and in particular, when used as a liquid crystal display device, a high luminance improvement effect can be obtained. The relative reflectance of the white film is preferably 100% or more. More preferably - 21 - 201119839 100.5% or more, further preferably 101% or more. The upper limit is not particularly limited 'but in practice, it is 120% or less. The controlled relative reflectance is more than 100% A white film excellent in whiteness and reflection characteristics can be obtained, and in particular, when used as a liquid crystal display device, a high luminance improvement effect can be obtained. To adjust the total light transmittance or relative reflectance of the white film to In the range as described above, it can be obtained by 1) controlling the dispersion diameter and density of the resin particles in the film to be in the range as described above, 2) increasing the thickness of the film, etc. (3) In the following, the method for producing the white film of the present invention will be described, but it is not limited thereto except for the stretching method. The polyester resin (al) and the incompatible component may be contained as needed ( b) The mixture is sufficiently vacuum dried and then supplied to a heated extruder equipped with a film forming apparatus of an extruder (main extruder). The addition of the incompatible component (b) is pre-uniformly usable. The masterbatch obtained by melt-kneading and blending may be pelletized, or may be directly supplied to a kneading extruder, etc. Since the dispersion of the incompatible component (b) may be promoted, it is preferred to use a polyester resin in advance. (a 1 ) The masterbatch obtained by uniformly melt-kneading the mixture with the incompatible component (b) is pelletized.

此外，在進行熔融擠出時，較佳爲經網眼40 m以下 之濾網加以過濾後，導入於T-模具內而以擠出成型獲得熔 融薄片。然後，將該熔融薄片在表面溫度經冷卻成10 °C -22- 201119839 以上且60 Ό以下之轉筒上，以靜電加以密著冷卻固化’ 以製造未延伸薄膜。 將該未延伸薄膜導入於經加熱成40°C以上且120°C以 下之溫度的輥群，並在不同周速的兩組輥間朝薄膜之進行 方向（薄膜長度方向）加以延伸。亦即，利用輥之周速差 來延伸。在該延伸中，以每單面8.5 W/cm以上且40 W/cm 以下之熱量Q加熱薄膜之至少一表面。熱量Q的下限較 佳爲10 W/cm以上。熱量Q的上限較佳爲25 W/cm以下。 所謂的「熱量Q」是意謂照射於薄膜寬度方向每1 cm薄 膜之表面的熱量。 若熱量Q爲小於8.5 W/cm時，則薄膜表面之溫度無 法充分地上升、而在表面形成凹陷、造成產生粉末等所引 起之製程污染。若熱量Q爲超過40 W/cm時，則在進行縱 向延伸時之薄膜軟化，以致無法穩定地進行製膜。 加熱用熱源是可使用紅外線加熱器或熱風。從能源效 率的觀點來考慮，則較佳爲紅外線加熱器。 紅外線加熱器之種類是並無特殊限制，可使用近紅外 線加熱器或純碳加熱器（carbon heater)等。從加熱性能 與耐用期限之均衡的觀點來考慮，則更佳爲純碳加熱器。 紅外線加熱器較佳爲在背面附有金反射膜。此外，也可使 用集光裝置。如此之加熱器是賀利氏有限公司（Heraeus Ltd.)製造之Twin Tube透明石英玻璃製之純碳加熱器。 紅外線加熱器是設置成使得加熱器之長度方向與薄膜 -23- 201119839 寬度方向成平行。紅外線加熱器之長度較佳爲比薄膜 度爲長，使其可在薄膜寬度方向均勻地加熱薄膜面。 線加熱器可爲1支，也可朝薄膜長度方向並排數支。 膜速度爲緩慢時，則可爲1支，若製膜速度爲快速時 較佳爲並排數支。上限是並無特殊限制，但是由於輥 間隙，在實務應用上是以4支爲上限。 此外，紅外線加熱器是設置於薄膜之單側或兩側 少設置於具有氣泡之層的一側。 紅外線加熱器向薄膜側之輸出功率（熱量）S較 薄膜之每單面爲35 W/cm以上且150 W/cm以下。另 在薄膜之單面設置數個紅外線加熱器的情況，則爲紅 加熱器每1支之向薄膜側之輸出功率乘以薄膜每單面 熱器支數所獲得之値。紅外線加熱器之輸出功率並非 部向薄膜側，而也包含未到達薄膜面的損失分。向薄 之輸出功率係經對紅外線加熱器之額定輸出功率（ )乘以紅外線加熱器固有之照射效率即可計算得。在 謂「紅外線加熱器向薄膜側之輸出功率」係經以下式 得之値。Further, in the case of melt extrusion, it is preferably filtered through a sieve having a mesh size of 40 m or less, and then introduced into a T-die to obtain a melted sheet by extrusion molding. Then, the molten flakes were cooled to a temperature of 10 ° C -22 - 201119839 or more and 60 Ό or less on the drum at a surface temperature to be electrostatically cooled and solidified by electrostatic ECU to produce an unstretched film. The unstretched film is introduced into a roll group heated to a temperature of 40 ° C or higher and 120 ° C or lower, and stretched in the film direction (film length direction) between the two sets of rolls at different peripheral speeds. That is, it is extended by the circumferential speed difference of the rolls. In this extension, at least one surface of the film is heated with a heat Q of 8.5 W/cm or more and 40 W/cm or less per one side. The lower limit of the heat Q is preferably 10 W/cm or more. The upper limit of the heat amount Q is preferably 25 W/cm or less. The term "heat Q" means heat applied to the surface of the film per 1 cm of the film width direction. If the amount of heat Q is less than 8.5 W/cm, the temperature of the surface of the film may not rise sufficiently, and a process may be formed such that a depression is formed on the surface, causing generation of powder or the like. When the amount of heat Q is more than 40 W/cm, the film is softened when the longitudinal direction is extended, so that film formation cannot be performed stably. The heat source for heating can use an infrared heater or hot air. From the viewpoint of energy efficiency, an infrared heater is preferred. The type of the infrared heater is not particularly limited, and a near-infrared heater or a carbon heater can be used. From the standpoint of the balance between heating performance and durability, it is more preferable to be a pure carbon heater. The infrared heater preferably has a gold reflective film attached to the back surface. In addition, a light collecting device can also be used. Such a heater is a pure carbon heater made of Twin Tube transparent quartz glass manufactured by Heraeus Ltd. The infrared heater is arranged such that the length direction of the heater is parallel to the width direction of the film -23-201119839. The length of the infrared heater is preferably longer than the film thickness, so that the film surface can be uniformly heated in the film width direction. The line heater can be one or several rows side by side in the length of the film. When the film speed is slow, it may be one, and if the film forming speed is fast, it is preferably a side by side. The upper limit is not particularly limited, but due to the roll gap, the practical application is limited to four. Further, the infrared heater is disposed on one side or both sides of the film and is disposed on one side of the layer having the bubble. The output power (heat) S of the infrared heater to the film side is 35 W/cm or more and 150 W/cm or less per one side of the film. In the case where a plurality of infrared heaters are provided on one side of the film, the output power of each of the red heaters toward the film side is multiplied by the number of heat exchangers per one side of the film. The output power of the infrared heater is not directed to the film side, but also includes loss points that do not reach the film surface. The output power to the thin is calculated by multiplying the rated output power ( ) of the infrared heater by the illumination efficiency inherent to the infrared heater. The "output power of the infrared heater to the film side" is obtained by the following formula.

• S = S' X E X N S: 紅外線加熱器向薄膜側之輸出功率（W/cm) S’ ：紅外線加熱器每1支之額定輸出功率（W/cm) E：紅外線加熱器之照射效率； N: 薄膜每單面之加熱器支數。 之寬 紅外 若製 ，則 間之 。至 佳爲 外， 外線 之加 爲全 膜側 W/cm 此所 計算 -24- 201119839 向薄膜側之輸出功率的下限更佳爲40 W/cm以上、特 佳爲 50 W/cm以上。向薄膜側之輸出功率的上限更佳爲 100 W/cm以下' 特佳爲80 W/cm以下。在縱向延伸時， 若紅外線加熱器向薄膜側之輸出功率爲超過150 W/cm時 ，則在縱向延伸時有可能導致薄膜軟化的情況。其結果， 則有可能造成無法穩定地進行製膜的情況。在縱向延伸時 ，若紅外線加熱器向薄膜側之輸出功率爲少於35 W/cm時 ，則有可能薄膜表面之溫度無法充分地上升的情況。其結 果，則有可能在表面形成凹馅而發生由粉末等所引起之製 程污染的情況。 從紅外線加熱器至薄膜表面之距離較佳爲5 mm以上 且100 mm以下。距離的下限更佳爲10 mm以上。距離的 上限更佳爲50 mm以下、特佳爲20 mm以下。若從紅外 線加熱器至薄膜表面之距離爲超過100 mm時，對於如上 所述紅外線加熱器之輸出功率範圍而言，則有可能導致因 紅外線到達薄膜之前即衰減，而無法充分地提高薄膜表面 溫度的情況。若紅外線加熱器與薄膜之距離爲小於5 mm 時，則對於該紅外線加熱器之輸出功率範圍而言，則有可 能導致薄膜厚度方向整體會軟化的情況。其結果，則有可 能造成無法穩定地進行製膜的情況。另外，所謂的「從紅 外線加熱器至薄膜表面之距離」是意謂從紅外線加熱器之 加熱管中心軸至薄膜表面的距離。 薄膜通過照射區之時間較佳爲0.2秒鐘以上且短於2 -25- 201119839 秒鐘。通過時間的下限更佳爲0.4秒鐘以上。通過時間的 上限更佳爲1秒鐘以下。所謂的「照射區」是意謂每1支 加熱器以加熱管爲中心而朝薄膜長度方向爲40 mm (從加 熱管之位置向上游側爲20 mm、向下游側爲20 mm )之區 域。若在紅外線加熱器爲並排2支以上的情況，則爲除了 各加熱器所佔有照射區的重複部分以外之合計距離。若通 過時間爲短於0.2秒鐘時，則有可能導致薄膜之升溫不充 分的情況。若通過時間爲2秒鐘以上時，則有可能導致薄 膜內部之溫度變爲高溫而使得氣泡無法增大的情況。其結 果，則有可能造成反射率變小的情況。 在延伸中，經加熱薄膜表面，則在薄膜表面部之延伸 張力變小而使得氣泡之形成受到阻礙。與此同時，在薄膜 內部，熱傳導率因開始形成的氣泡而變低，使得比薄膜表 面部爲較不易加熱。其結果，在薄膜內部’因延伸引起之 延伸張力則充分發生而促進氣泡之形成。亦即’可形成薄 膜表面部是氣泡少、而薄膜內部是氣泡多之白色薄膜。 假設主要樹脂成分（a)之玻璃轉移溫度爲Tg(°C) 時，則延伸前之薄膜溫度較佳爲（Tg-20°C )以上且Tg以 下。「延伸前之薄膜溫度」是意謂通過經加熱的輥群，且 以熱量Q加熱表面前之薄膜溫度。延伸前之薄膜溫度是在 製膜時之縱向延伸倍率設定爲1·〇倍’且將以未經熱量Q 之表面加熱的狀態所通過延伸區之薄膜溫度’以放射溫度 計加以測定即可獲得。延伸前之薄膜溫度的下限更佳爲（ -26- 201119839• S = S' XEXNS: Output power of the infrared heater to the film side (W/cm) S' : rated output power per unit of the infrared heater (W/cm) E: Irradiation efficiency of the infrared heater; N: The number of heaters per side of the film. The width of the infrared if the system, then between. In addition, the outer line is added to the full film side W/cm. This calculation is -24- 201119839 The lower limit of the output power to the film side is preferably 40 W/cm or more, and particularly preferably 50 W/cm or more. The upper limit of the output power to the film side is preferably 100 W/cm or less, and particularly preferably 80 W/cm or less. When extending in the longitudinal direction, if the output power of the infrared heater to the film side is more than 150 W/cm, there is a possibility that the film is softened when it is extended in the longitudinal direction. As a result, there is a possibility that the film formation cannot be performed stably. When the output power of the infrared heater to the film side is less than 35 W/cm in the longitudinal direction, the temperature of the film surface may not be sufficiently raised. As a result, it is possible to form a concave filling on the surface to cause contamination of the process caused by powder or the like. The distance from the infrared heater to the surface of the film is preferably 5 mm or more and 100 mm or less. The lower limit of the distance is preferably 10 mm or more. The upper limit of the distance is preferably 50 mm or less, and particularly preferably 20 mm or less. If the distance from the infrared heater to the surface of the film is more than 100 mm, the output power range of the infrared heater as described above may cause attenuation due to the infrared rays before reaching the film, and the surface temperature of the film may not be sufficiently increased. Case. If the distance between the infrared heater and the film is less than 5 mm, the output power range of the infrared heater may cause the entire thickness of the film to soften. As a result, there is a possibility that the film formation cannot be performed stably. Further, the term "distance from the infrared heater to the surface of the film" means the distance from the central axis of the heating tube of the infrared heater to the surface of the film. The time during which the film passes through the irradiation zone is preferably 0.2 seconds or more and shorter than 2 - 25 - 201119839 seconds. The lower limit of the passage time is more preferably 0.4 seconds or more. The upper limit of the passage time is preferably 1 second or less. The term "irradiation zone" means a zone in which the length of the film is 40 mm (20 mm from the position of the heating pipe to the upstream side and 20 mm to the downstream side) centering on the heating pipe. In the case where the infrared heaters are arranged in two or more rows, the total distance is other than the overlapping portion of the irradiation regions occupied by the heaters. If the passage time is shorter than 0.2 seconds, there is a possibility that the temperature of the film is insufficient. When the passage time is 2 seconds or longer, there is a possibility that the temperature inside the film becomes high and the bubble cannot be increased. As a result, there is a possibility that the reflectance becomes small. In the stretching, when the surface of the film is heated, the stretching tension at the surface portion of the film becomes small, so that the formation of bubbles is hindered. At the same time, in the inside of the film, the thermal conductivity is lowered by the bubbles which are initially formed, so that it is less heated than the surface of the film. As a result, the stretching tension due to the elongation inside the film sufficiently occurs to promote the formation of bubbles. That is, the surface portion on which the film can be formed is a white film having a small number of bubbles and a large number of bubbles inside the film. When the glass transition temperature of the main resin component (a) is Tg (°C), the film temperature before stretching is preferably (Tg - 20 ° C) or more and Tg or less. The "film temperature before stretching" means the film temperature before passing through the heated roll group and heating the surface with heat Q. The film temperature before stretching is obtained by measuring the longitudinal stretching ratio at the time of film formation to 1 〇 ’ and measuring the film temperature of the extending region in a state where the surface of the heat-free Q is not heated by a radiation temperature meter. The lower limit of the film temperature before stretching is more preferable ( -26- 201119839

Tg-15°C )以上。延伸前之薄膜溫度的上限更佳爲（Tg_5 °C )以下。特別是在主要樹脂成分（a )爲PET的情況， 延伸前之薄膜溫度較佳爲60°C以上且80°C以下。經設定 爲（Tg-20°C )以上且Tg以下，則可使得薄膜內部之氣泡 形成變大，因此可提高反射性能。若爲低於（Tg-20t：) 時，則薄膜之伸度變小，有可能導致薄膜破裂的情況。若 高於Tg時，則薄膜所產生之延伸張力不足夠，在主要樹 脂成分（a )與非相溶性成分（b )之界面的剝離不易發生 ，因此’不易形成空隙。其結果，則有可能造成作爲反射 板的反射性能不足夠的情況。經控制延伸前之薄膜溫度之 方法則有將經加熱的輥群之輥溫度，因應薄膜之速度及輥 之材質或薄膜之材質的熱傳導係數來加以調整之方法。 一邊以如前所述方法加熱，一邊朝薄膜長度方向加以 延伸3.0倍以上且4.5倍以下，其後則以溫度爲20°C以上 且50 °C以下之輥群進行冷卻。薄膜長度方向之延伸倍率 較佳爲3.4倍以上且4.5倍以下。若延伸倍率爲少於3.0 倍時，則氣泡無法形成足夠的大小，因此無法獲得足夠的 反射率。若延伸倍率爲超過4.5倍時，則在其後續之橫向 延伸，（transverse stretching )(朝薄膜寬度方向之延伸） 中’則將導致容易破裂而使得生產性變差，因此爲不佳。 接著，一邊以鋏具夾持著薄膜之兩端，一邊導入於拉 幅機中，並在經加熱成90 °C以上且150°C以下之溫度的雰 圍氣中，朝與薄膜長度方向成直角的方向（薄膜寬度方向 -27- 201119839 )加以延伸3倍以上且5倍以下。若延伸倍率爲小於3倍 時，則氣泡尺寸小，以致無法獲得足夠的反射率。若延伸 倍率爲超過5倍時，則容易破裂而使得生產性變差，因此 爲不佳。經設定薄膜長度方向之延伸倍率及薄膜寬度方向 之延伸倍率的乘積爲大，則可更進一步地提高反射性能。 爲使所獲得之經雙軸向延伸薄膜之配向結晶化完成而 賦予平面性與尺寸穩定性，接著，即在拉幅機內在150°C 以上且240°C以下之溫度下進行1秒鐘以上且30秒鐘以下 之熱處理，然後均勻地緩慢冷卻後，冷卻至室溫。其後， 因應需要爲更進一步提高與其他素材之密著性而可施加電 暈放電處理等，然後加以捲取。在熱處理步驟中，因應需 要也可朝薄膜寬度方向或薄膜長度方向施加3%以上且 12%以下之鬆弛處理。視背光而定，在背光內部之雰圍氣 溫度有可能上升至約100 °C的情況，白色薄膜是需要具有 一定的熱尺寸穩定性。一般而言，熱處理溫度愈高，則熱 尺寸穩定性愈高，因此，較佳爲在190 °C以上之高溫進行 熱處理。Tg-15 ° C) or more. The upper limit of the film temperature before stretching is more preferably (Tg_5 °C) or less. In particular, when the main resin component (a) is PET, the film temperature before stretching is preferably 60 ° C or more and 80 ° C or less. When it is set to (Tg - 20 ° C) or more and Tg or less, the formation of bubbles inside the film can be increased, so that the reflection performance can be improved. If it is lower than (Tg-20t:), the elongation of the film becomes small, which may cause the film to rupture. When the temperature is higher than Tg, the stretching tension generated by the film is insufficient, and the peeling at the interface between the main resin component (a) and the incompatible component (b) is less likely to occur, so that it is difficult to form voids. As a result, there is a possibility that the reflection performance as the reflecting plate is insufficient. The method of controlling the film temperature before stretching has a method of adjusting the roll temperature of the heated roll group in accordance with the speed of the film and the heat transfer coefficient of the material of the roll or the material of the film. While being heated as described above, it is extended by 3.0 times or more and 4.5 times or less in the longitudinal direction of the film, and then cooled by a roll group having a temperature of 20 ° C or more and 50 ° C or less. The stretching ratio in the longitudinal direction of the film is preferably 3.4 times or more and 4.5 times or less. If the stretching ratio is less than 3.0 times, the bubbles cannot be formed in a sufficient size, so that sufficient reflectance cannot be obtained. If the stretching ratio is more than 4.5 times, it will be poor in the subsequent transverse stretching (in the direction of the film width direction), which will cause easy cracking and deteriorate productivity. Next, the both ends of the film are sandwiched by the cookware, and introduced into a tenter, and at a right angle to the length of the film, in an atmosphere heated to a temperature of 90 ° C or higher and 150 ° C or lower. The direction (film width direction -27-201119839) is extended by 3 times or more and 5 times or less. If the stretching ratio is less than 3 times, the bubble size is small, so that sufficient reflectance cannot be obtained. When the stretching ratio is more than 5 times, it is liable to be broken and the productivity is deteriorated, so that it is not preferable. When the product of the stretching ratio in the longitudinal direction of the film and the stretching ratio in the film width direction is set to be large, the reflection performance can be further improved. To impart planarity and dimensional stability in order to complete the alignment crystallization of the obtained biaxially stretched film, and then carry out at a temperature of 150 ° C or more and 240 ° C or less in a tenter for 1 second or longer. After heat treatment for 30 seconds or less, it was uniformly cooled slowly, and then cooled to room temperature. Thereafter, corona discharge treatment or the like may be applied to further improve the adhesion to other materials, and then taken up. In the heat treatment step, a relaxation treatment of 3% or more and 12% or less may be applied in the film width direction or the film length direction as needed. Depending on the backlight, the temperature of the atmosphere inside the backlight may rise to about 100 °C, and the white film needs to have a certain thermal dimensional stability. In general, the higher the heat treatment temperature, the higher the thermal dimensional stability. Therefore, it is preferred to carry out heat treatment at a high temperature of 190 °C or higher.

(4 )測定方法 A. 熱量Q(4) Measurement method A. Heat Q

到達薄膜面之熱量Q是以如下所述方式測定。將從薄 膜至熱源之距離調整成與製膜條件符合。在薄膜之兩表面 安裝熱電偶，並以兩面的溫度之平均作爲薄膜溫度。在靜 止薄膜之狀態以熱源加熱薄膜，並測定其升溫速度α ( °C -28- 201119839 /秒鐘）。以下式計算熱量Q。在第1圖是展示正在進行測 定的狀態之示意圖。The amount of heat Q reaching the film surface was measured as follows. The distance from the film to the heat source is adjusted to match the film forming conditions. A thermocouple was attached to both surfaces of the film, and the average of the temperatures on both sides was taken as the film temperature. The film was heated by a heat source in the state of the stationary film, and the temperature increase rate α (°C -28 - 201119839 / sec) was measured. The heat Q is calculated by the following formula. Fig. 1 is a schematic view showing a state in which measurement is being performed.

• Q= a xDxMxC Q ：向薄膜面到達之熱量（每單面薄膜）（W/cm)； α :升溫速度a ( °C /秒鐘）； D:薄膜表面的受熱部分之薄膜長度方向長度（cm) « Μ:薄膜面每lcm2之薄膜重量（g/cm2); C : 薄膜之比熱（J / (g * °C ))。 在使用紅外線加熱器的情況’ 「長度D ( cm )」是照 射區之長度。所謂的「照射區」是每1支加熱器以加熱管 爲中心而朝薄膜長度方向爲40 mm (從加熱管之位置向上 游側爲20 mm、向下游側爲20 mm )之區域。若在紅外線 加熱器爲並排2支以上的情況’則爲除了各加熱器所佔有 照射區的重複部分以外之合計長度。 比熱C ( J/(g · °C ))是根據〗IS K7 1 23 ( 1 987年版） 之準則來測定。在PET薄膜的情況，則爲C = 1.25 ( J/(g • 〇C ))。 此外，在使用紅外線加熱器的情況，向薄膜面到達之 熱量Q也可以下式計算得。但是，在設置數支紅外線加熱 器的情況，則從各紅外線加熱器至薄膜面之距離是可適用 於所有的情況。 • Q = S X ( 0.4 — 0.055 X ln(L)) -29- 201119839• Q= a xDxMxC Q : heat reaching the film surface (per single-sided film) (W/cm); α: heating rate a (°C / sec); D: film length direction of the heated portion of the film surface (cm) « Μ: film weight per cm2 of film surface (g/cm2); C: specific heat of film (J / (g * °C)). In the case of using an infrared heater, 'length D (cm)' is the length of the irradiation area. The "irradiation zone" is an area in which the length of the film is 40 mm (20 mm from the position of the heating pipe to the upstream side and 20 mm to the downstream side) centering on the heating tube. In the case where the infrared heater is two or more in parallel, the total length is the same as the overlapping portion of the irradiation area occupied by each heater. The specific heat C (J/(g · °C)) is determined according to the criteria of IS K7 1 23 (1998 Edition). In the case of PET film, it is C = 1.25 (J/(g • 〇C)). Further, in the case of using an infrared heater, the amount of heat Q reaching the film surface can also be calculated by the following formula. However, in the case where a plurality of infrared heaters are provided, the distance from each infrared heater to the film surface is applicable to all cases. • Q = S X ( 0.4 — 0.055 X ln(L)) -29- 201119839

S = S’ X E X N Q:向薄膜面到達之熱量（每單面薄膜）（W/cm)； S: 紅外線加熱器向薄膜側之輸出功率（每單面薄膜 )(W/cm )； L: 從紅外線加熱器至薄膜表面的距離（mm)； S’ ：紅外線加熱器每1支之額定輸出功率（W/cm ) > E： 照射效率； N： 薄膜每單面之加熱器支數。 B. 在薄膜表面的凹陷之存在密度 在薄膜表面蒸鏟鉑-鈀後，以場發射掃描式電子顯微 鏡(field emission scanning electron microscope )放大 2 5 00倍以獲得放大畫像。由放大畫像將在10 // m見方內 的長徑爲1/im以上之凹狀凹陷之個數加以計數。就不同 的1 0個視野進行相同操作，並以其平均値作爲凹陷之存 在密度。就薄膜之兩面進行如上所述測定，然後採用較高 者之値。場發射掃描式電子顯微鏡是使用日本電子股份有 限公司（JEOLLtd.)製造之 JSM-6700F。 C.相對反射率 以將0 60積分球及1〇°傾斜定位具安裝於分光光度計 之狀態測定560 nm之光反射率。另外’光反射率是對於 白色薄膜之兩面進行測定’而以較高者之數値作爲白色薄 膜之反射率。分光光度計是使用日立製作所股份有限公司 -30- 201119839 (Hitachi，Ltd.)製造之U-3410，0 60積分球是使用日立 製作所股份有限公司製造之130-0632 (內面爲硫酸鋇製） ’標準白色板是日立計測器服務股份有限公司（HUacln Instruments Service Co.，Ltd.)製造之 2 1 0-0740 (氧化鋁 )。相對反射率是以下列等級進行判定。若判定結果爲S 、A或B時，則爲合格。若爲S或A時，則爲較佳。 •相對反射率爲101 %以上且低於120%的情況：S ; •相對反射率爲100%以上且低於101%的情況：A ; •相對反射率爲9 9钇以上且低於1 0 0 %的情況：B ; •相對反射率爲低於9 9 %的情況：C * D. 比重 將白色薄膜切成5 cmx5 cm之大小，然後根據JIS K7 1 1 2 ( 1 980年版）之準則使用電子比重計進行測定。此 外，就各白色薄膜準備5片分別測定，並以其平均値作爲 白色薄膜之比重。電子比重計是使用Mirage Co.，Ltd.製造 之SD-1 20L。比重是以下列等級進行判定。若判定結果爲 S、A或B時，則爲合格。 •比重爲〇. 5 5以上且〇. 9以下的情況：S ; •比重爲大於0.9且1.0以下的情況：A ; •比重爲大於1 · 0且1.3以下的情況：B ; •比重爲大於1.3的情況：C。 E. 製膜性 由製膜時的薄膜破裂之頻率，以下列等級進行製膜性 -31 - 201119839 評估。對於大量生產則需要S、A或B之製膜性。若爲S 或A時’則有進一步降低成本之功效。 . 薄膜破裂在一個星期有1次以下的情況：S; •薄膜破裂在一個星期有2次以上且5次以下的情 況：A ; • 薄膜破裂在一個星期有6次或7次的情況： •薄膜破裂在一個星期有8次以上的情況：C。 F. 製膜生產線之污染評估 在製膜中之縱向延伸的冷卻輥群中，以究竟有多少薄 膜通過後，在其任一輥之表面的薄膜所通過之面整體或端 部觀察到污染來評估製膜生產線污染。在觀察到污染附著 的情況，則需要清掃，且在清掃中無法進行生產，因此從 生產性的觀點來考慮，若爲S或A時則爲合格，更佳爲S 〇 •通過5萬公尺後也觀察不到污染：S; •通過1萬公尺後雖然觀察不到污染，但是通過5萬 公尺後則觀察到污染：A ; •通過2000公尺後雖然觀察不到污染，但是通過1 萬公尺後則觀察到污染：B ; •通過2000公尺後觀察到污染：C» G. 非相溶性成分（b )之玻璃轉移溫度 在可以單獨獲得非相溶性成分（b )的情況，則將經 將5毫克之非相溶性成分（b )加以熔解及驟冷所獲得之 -32- 201119839 試樣’使用示差掃描熱量測定計從25 °C以2(TC /分鐘之升 溫速度加以升溫，並將〗IS K7121C 1987年版）準則之中 間點玻璃轉移溫度視爲玻璃轉移溫度來測定。示差掃描熱 量測定計是使用博精儀器公司（Perkin Elmer, Inc.)製造 之DSC-2型。 此外’在無法以單獨獲得非相溶性成分（b )的情況 ，則經由白色薄膜單離非相溶性成分（b)後，使用示差 掃描熱量測定計測定玻璃轉移溫度。例如，在由聚酯樹脂 (a 1 )、作爲非相溶性之熱塑性樹脂（b 1 )的環狀烯烴共 聚物、及無機粒子（b2 )所構成之白色薄膜的情況，則將 白色薄膜溶解於體積分率爲1:1之甲醇與氯仿混合溶液的 未溶解物加以過濾取出。將該未溶解物再溶解於氯仿後取 出未溶解物，並溶解於由體積分率爲1:1之六氟異丙醇與 氯仿之混合溶液。將其溶液以離心分離器加以離心分離後 ，採取浮游物即可獲得環狀烯烴共聚物。將5毫克如上所 述所獲得之環狀烯烴共聚物加以熔解及驟冷所獲得之試樣 ，使用示差掃描熱量測定計從25 °C以20 °C/分鐘之升溫速 度加以升溫，並將JIS K7 1 2 1 ( 1 987年版）準則之中間點 玻璃轉移溫度視爲玻璃轉移溫度即可測定。示差掃描熱量 測定計是使用例如博精儀器公司製造之D S C - 2型。 H. 延伸前之薄膜溫度 設定製膜條件中之縱向延伸倍率爲1.0倍，且停止使 用紅外線加熱器之加熱。使用放射溫度計量測5次的通過 -33- 201119839 縱向延伸之延伸區的薄膜溫度’而以其平均値作爲延伸即 之薄膜溫度。此時，預先實施對象的薄膜之放射率補正。 放射溫度計是使用 Keyence公司（Keyence Corporation) 製造之IT2-80R。 《實施例》 在下文中，則配合實施例等更具體地說明本發明，但 是本發明並不受限於此等者。 (原料） • 聚酯樹脂（al-Ι ) 酸成分是使用對苯二甲酸、二醇成分是使用乙二醇' 且將三氧化銻（聚合觸媒）添加成相對於所獲得之聚酯九 粒以銻原子換算計爲300 ppm，進行聚縮合反應以獲得極 限黏度爲0.63 dl/g、羧基末端基量爲40當量/噸之聚對苯 二甲酸乙二醇酯九粒（PET )。經使用示差熱分析計測定 結晶熔解熱量（crystal melting heat)結果，則爲1 cal/g 以上，此爲結晶性之聚酯樹脂。測定該樹脂之熔點Tm結 果爲25 0°C。 • 環狀烯烴共聚物樹脂（bl-1) 使用玻璃轉移溫度爲178°C、MVR(260°C/2.16 kg) 爲 4.5 ml/10 min 之環狀烯烴樹脂「TOPAS」 （Polyplastics 公司製造）。另外，經使用示差熱分析計測定結晶熔解熱 量結果，則爲少於1 cal/g，此爲非晶性樹脂。 . 環狀烯烴共聚物樹脂（bl-2) -34- 201119839 使用玻璃轉移溫度爲 158°C、MVR( 260°C/2.16 kg) 爲 4.5 ml/10 min 之環狀烯烴樹脂「TOPAS」（Polyplastics 公司製造）。另外，經使用示差熱分析計測定結晶熔解熱 量結果，則爲少於1 cal/g，此爲非晶性樹脂。 • 烯烴樹脂（bl-3) 使用玻璃轉移溫度爲25°C、熔點爲235 °C ' MFR ( 260 °C/5 kg)爲8 g/10 min之烯烴樹脂PMP (聚甲基戊烯）「 TPX」（三井化學股份有限公司（Mitsui Chemicals, Inc,) 製造）。 • 共聚合聚酯樹脂（c-1 ) 使用CHDM (環己烷二甲醇）共聚合PET。該樹脂是 在共聚合二醇成分將30 mol %之環己院二甲醇加以共聚合 所獲得之PET。經使用示差熱分析計測定結晶熔解熱量結 果，則爲少於1 cal/g，此爲非晶性樹脂。 • 共聚合聚酯樹脂（c-2) 使用CHDM (環己烷二甲醇）共聚合PET。該樹脂是 在共聚合二醇成分將60 mol %之環己烷二甲醇加以共聚合 所獲得之PET。經使用示差熱分析計測定結晶熔解熱量結 果，則爲少於1 cal/g，此爲非晶性樹脂。 • 共聚合聚酯樹脂（c-3 ) 使用間苯二甲酸共聚合PET。該樹脂是在共聚合二竣 酸成分將17·5 mol%之間苯二甲酸加以共聚合所獲得之 PET。經使用示差熱分析計測定結晶熔解熱量結果，則爲 -35- 201119839 少於1 cal/g，此爲非晶性樹脂。 • 分散劑（d-1 ) 使用PBT-PAG (聚伸院基二醇）共聚物。該樹脂是 PBT (聚對苯二甲酸丁二醇酯）與PAG (主要爲聚四亞甲 基二醇）之嵌段共聚物。經使用示差熱分析計測定結晶熔 解熱量結果，則爲1 cal/g以上，此爲結晶性樹脂。 〔實施例1〕 將如表1所示原料之混合物在180°C之溫度真空乾燥 3小時後供應至擠壓機。在280 °C之溫度下加以熔融擠出 後，以30 /Z m截止濾網加以過濾，然後導入於T-模具。 其次，從T-模具內擠出成薄片狀作爲熔融單層薄片。 將熔融單層薄片在表面溫度保持在25 °C之轉筒上，以施 加靜電法使其貼緊冷卻固化，以獲得未延伸單層薄膜。此 時，假設接於轉筒的薄膜面爲背面’而接於空氣的面爲正 面。其次，將未延伸單層薄膜以加熱成85 °C溫度之輥群 預熱後，一邊以如表4所示紅外線加熱器之條件從薄膜之 兩面照射，一邊利用輥之周速差而朝薄膜長度方向進行 3.6倍之延伸，然後以溫度爲25°C之輥群加以冷卻，以獲 得單軸向延伸薄膜。紅外線加熱器是使用賀利氏有限公司 製造之純碳加熱器「CZB8000/1000G」且以單側爲2支而 佈置於兩側。加熱器是長度爲1m、每1支之額定輸出功 率爲80 W/cm之加熱器。並且，將供應至加熱器之電力調 整成符合如表4所示紅外線加熱器之條件。另外，如表中 -36- 201119839 所示之有關加熱條件之數値等是每單面之數値。 一邊以鋏具夾持著所獲得單軸向延伸薄膜之兩端，一 邊導入於拉幅機內溫度爲95 °C之預熱區，其次，連續地 在105 °C溫度之加熱區朝與薄膜長度方向成正交的方向（ 薄膜寬度方向）加以延伸3.6倍。並且，接著在拉幅機內 之熱處理區在190°C下施加20秒鐘之熱處理，更進一步在 180°C溫度下朝6%寬度方向施加鬆弛處理後，再在140°C 溫度下朝1 %寬度方向施加鬆弛處理。其次，均句地緩慢 冷卻後加以捲取。經如上所述可獲得厚度爲1 88 β m之單 層白色薄膜。經觀察該白色薄膜之截面結果，在內部含有 許多微細的氣泡。此外，薄膜表面之凹陷個數少，又無輥 污染且製膜性也優異。薄膜之各種特性如表7所示。 〔實施例2至7〕 除了分別設定爲如表4所示紅外線加熱器之條件以外 ，其餘則以與實施例1相同的方式進行製膜，以獲得厚度 爲188/zm之單層白色薄膜。經觀察該白色薄膜之截面結 果’在內部含有許多微細的氣泡。此外，薄膜表面之凹陷 個數少’又無輥污染且製膜性也優異。薄膜之各種特性如 表7所示。 〔實施例8至15、17、22至24〕 除了分別設定爲如表1、2所示原料組成等以外，其 餘則以與實施例1相同的方式進行製膜，以獲得厚度爲 1 88//m之單層白色薄膜。經觀察該白色薄膜之截面結果 -37- 201119839 ’在內部含有許多微細的氣泡。此外，薄膜表面之凹陷個 數少，輥污染少且製膜性也優異。薄膜之各種特性如表7 、8所示。 〔實施例1 6〕 將如表2所示原料之混合物在180°C之溫度真空乾燥 3小時後供應至擠壓機（A )。此外，將聚酯樹脂（a 1 -1 ) 另外在180°C之溫度下乾燥3小時後供應至擠壓機（B) 。將供應至擠壓機（A)之原料及供應至擠壓機（B)之 原料分別在28(TC之溫度加以熔融、供應至進料分流套管 (feed block )。在進料分流套管則朝厚度方向將由供應 至擠壓機（A)之原料所構成之層（A層）、與由供應至 擠壓機（B).之原料所構成之層（B層）積層成A層“層 之二層積層後導入於T-模具。 其次，從T-模具內擠出成薄片狀，作爲由A層/B層 所構成之熔融二層積層未延伸薄片。將熔融積層薄片在保 持於表面溫度25 °C之轉筒上，以施加靜電法使其貼緊冷 卻固化，以獲得未延伸積層薄膜。此時，B層表面是接於 轉筒而A層表面是接於空氣。亦即，B層表面是成爲背面 ’而A層表面則成爲正面。 接著，以加熱成85 °C溫度之輥群預熱未延伸積層薄 膜後，一邊以如表5所示紅外線加熱器之條件僅由A層表 面側（正面）照射，一邊利用輥之周速差而朝薄膜長度方 向進行3.6倍之延伸，並以溫度爲2 5 °C之輥群加以冷卻， -38- 201119839 以獲得單軸向延伸薄膜。 一邊以鋏具夾持著所獲得單軸向延伸薄膜之兩端，一 邊導入於拉幅機內溫度爲95 °C之預熱區，接著，連續地 在105 °C溫度之加熱區朝與薄膜長度方向成正交的方向（ 薄膜寬度方向）加以延伸3.6倍。並且’接著在拉幅機內 之熱處理區在190°C下施加20秒鐘之熱處理，更進一步在 180 °C溫度下朝6%寬度方向施加鬆弛處理後，再在140 °C 溫度下朝1 %寬度方向施加鬆弛處理。其次，均勻地緩慢 冷卻後加以捲取。經如上所述可獲得厚度爲1 8 8 // m之積 層白色薄膜。經觀察該白色薄膜之截面結果，在A層內部 含有許多微細的氣泡。此外，正面、背面皆爲在薄膜表面 之凹陷個數少，又無輥污染且製膜性也優異。薄膜之各種 特性如表8所示。 〔實施例18至21、27〕 除了分別設定爲如表5所示延伸倍率等以外，其餘則 以與實施例1相同的方式進行製膜，以獲得厚度爲1 8 8 " m之單層白色薄膜。經觀察該白色薄膜之截面結果，在內 部含有許多微細的氣泡。此外·，薄膜表面之凹陷個數少， 輥污染少且製膜性也優異。薄膜之各種特性如表8所示。 〔實施例25、26〕 除了分別設定爲如表5所示預熱輥溫度、紅外線加熱 器條件以外’其餘則以與實施例1相同的方式進行製膜， 以獲得厚度爲188#m之單層白色薄膜。經觀察該白色薄 -39- 201119839 膜之截面結果’在內部含有許多微細的氣泡。此外，薄膜 表面之凹陷個數少’輥污染少且製膜性也優異。薄膜之各 種特性如表8所示。 〔比較例1、2、4〕 除了分別設定爲如表6所示紅外線加熱器之條件等以 外，其餘則以與實施例1相同的方式進行製膜，以獲得厚 度爲188/zm之單層白色薄膜。製膜性是比實施例1爲差 者。經觀察該白色薄膜之截面結果，在內部含有微細的氣 泡。由於熱量Q爲少於8.5 W/cm，薄膜表面之溫度無法充 分地上升，以致薄膜表面之凹陷個數增多。因此，輥污染 也多’結果導致需要頻繁的清掃。薄膜之各種特性如表9 所示。 〔比較例3〕 除了設定爲如表6所示紅外線加熱器之條件等以外， 其餘則以與實施例1相同的方式進行製膜。由於熱量Q超 過40 W/cm ’在進行長度方向（縱向）延伸時，薄膜會軟 化、薄膜發生熱垂現象，結果導致無法製膜。 〔比較例5〕 # 7設定爲如表6所示紅外線加熱器之條件以外，其 # M U胃實施例1 6相同的方式進行製膜，以獲得厚度爲 1 88 之積層白色薄膜。製膜性是屢次發生破裂而比實 施例16爲差者。經觀察該白色薄膜之截面結果，在如表3 所τκ由混合原料構成之層的內部含有微細的氣泡。由於熱 -40- 201119839 量Q爲少於8.5 W/cm’薄膜表面之溫度無法充分地上升， 以致薄膜表面之凹陷個數增多。因此，輥污染也多，結果 導致需要頻繁的清掃。薄膜之各種特性如表9所示。 〔比較例6〕 除了設定爲如表3所示原料組成等以外，其餘則以與 實施例1相同的方式進行製膜，以獲得厚度爲188#m之 單層透明薄膜。在縱向延伸時，邊緣部會發生熱垂，使得 縱向延伸後之薄膜寬度會變動，因此獲得厚度不均勻性爲 大的薄膜。由於未含有非相溶性成分，因此並無輥污染。 然而，由於薄膜內部並無氣泡而反射率小，因此其係不適 合用作爲反射薄膜之薄膜。薄膜之各種特性如表9所示。 〔比較例7、1 2〕 除了分別設定爲如表3所示原料組成等以外，其餘則 以與實施例1相同的方式進行製膜，以獲得厚度爲丨88 # m之單層白色薄膜。比較例7是經觀察白色薄膜之截面結 果’空隙連結形成大空隙。製膜性是不穩定且屢次發生破 裂。 比較例12是經觀察白色薄膜之截面結果，在內部含 有微細的氣泡。由於熱量Q爲少於8.5 W/cm，薄膜表面之 溫度無法充分地上升’以致薄膜表面之凹陷個數增多。因 此，輥污染也多’結果導致需要頻繁的清掃。 薄膜之各種特性如表9所示。 〔比較例9至1 1、1 3〕 -41 - 201119839 除了分別設定爲如表6所示延伸倍率等以外，其餘則 以與實施例1相同的方式進行製膜，以獲得厚度爲1 8 8 # m之單層白色薄膜。經觀察該白色薄膜之截面結果，在內 部含有許多微細的氣泡。 比較例9是薄膜長度方向之延伸倍率爲大於4.5倍， 比較例11是薄膜寬度方向之延伸倍率爲大於5倍，因此 薄膜表面之凹陷個數增多。因此，輥污染也多，結果導致 需要頻繁的清掃。 比較例1 0是薄膜寬度方向之延伸倍率爲小於3倍， 比較例13是薄膜寬度方向之延伸倍率爲小於2.9倍，因 此，薄膜表面之凹陷個數少、輥之污染少。但是，反射率 卻小，因此其係不適合用作爲反射薄膜之薄膜。此外，比 較例13是在橫向延伸時容易發生破裂。 薄膜之各種特性如表9所示。 -42- 201119839 ι撇 4 i i ϋ 其他成分 /-S ^1¾ 'Sw〆 to VO P /"s 承— Ο ώ 祐 Xm ul /-N ^ CN Ο ώ 〇H v〇pg l/~j CJ ΜΪ 1 /-~N p si /―s Φ 班 /-N 2 'w rfJ Μ 每 壊 (ff%) m JO <n 〇 un Ό & Ρ 氧化欽 氧化鈦 氧化鈦 氧化鈦 _1 氧化鈦 氧化駄 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化欽 氧化駄 氧化鈦 氧化欽 氧化欽 /-Ν I-1 Μ ¢1 劉 銳 /-Ν Η§ ^1¾ yn W-) v〇 m cn o IT) m in Sec) 00 1 i oo 〇〇 1 1 〇〇 OO oo H 00 1 < oo OO oo ( oo oo r—< 00 1 1 oo 00 1 Ή 騷 tisIS ι1πΠΐ P ^Sffbl-1) /~s I 1 1 勁5 爱am 1蠢 嵌 N ®5 輕flm 心an i| /•~N »-Η 1 翅5 ll m ίΚ /-N i 1 翅5 囊flm: a>c〇3 il m H 1 製5 餐舰 il m « 1 翅5 爱iJm n m 味 共聚 iSffbl-1) <-1 1 «5 裝am 心tCQ _ 1 共聚 S1fEl-l) r-\ 1 < 1 勁5 遲inn 4^tu3 is 跋 甲( /—N 翅5 爱am J>C〇3 il 齡 1 1 1 a5 輕am iL^〇33 11 齡 se 爱am A-^noa 11 m 抹 聚酯樹脂U1) 含量 (質量％) g g § JO VQ to 種類 PET PET PET PET PET PET PET PET PET ! PET PET PET PET PET PET 實施例1 實施例2 實施例3 實施例4 實施例5 實施例6 實施例7 實施例8 實施例9 實施例10 實施例11 實施例12 實施例13 實施例14 實施例15 _ ε寸— 201119839 1 薄膜組成 其他成分 会畺 (質量％) cn 1 間苯二甲酸17.5 mol% 共聚合PET (c-3) 非相溶性成分⑻ 無機粒子（b2) 含量 (質量％) VO Ο VO 種類 硫酸鋇 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 ^—1 m Π35 m ψί 会暑 (質量％) cn cs in <Γ) i/Ί ο tn m 玻璃轉移溫度 rc) oo 〇〇 r Η oo oo 00 1 ' < 〇〇 F Η OO 1—^ <Ν oo 00 1 < oo 劉 & irk m ^Is w 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-1) 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-2) 烯烴樹脂（bl-3.) 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-l) 環狀烯烴 共聚物樹脂（bl-l) 聚酯樹脂⑷ 含量 (質量％) o § § § 騷 t1nn< P PET PET PET PET PET PET PET PET I PET I PET 1 i PET PET 實施例16 實施例17 實施例18 實施例19 實施例20 實施例21 實施例22 實施例23 |實施例24 實施例25 實施例26 實施例27 -寸寸- 201119839 e嗽 1 薄膜組成 其他成分 含量 (質量％) CO P 間苯二甲酸17.5 mol% 共聚合PET (c-3) 非相溶性成分⑻ 無機粒子（b2) 含量 (質量％) VO to ο υ-1 騷 >1mi1 w 氧化鈦 氧化鈦 氧化鈦 氧化鈦 硫酸鋇 氧化敍 氧化鈦 氧化鈦 氧化鈦 氧化鈦 氧化鈦 熱塑性樹脂（bl) 含量 (質量％) VO un VO CN to VO ο 玻璃轉移溫度 rc) 〇〇 oo 1 oo »—H 00 1 1 OO oo oo OO wn CN 00 1 < 種類 環狀烯烴 共聚物樹脂（bl-1) 職烯烴 共聚物樹脂（bl-1) 環狀烯烴 共聚物樹脂（bl-1) 環狀烯烴 共聚物樹脂（bl-1) 環狀烯烴 共聚物樹脂（bl-1) 環狀烯烴 共聚物樹脂（bl-1) 環狀烯烴 共聚物樹脂（bl-1) 職烯烴 共聚物樹脂（bl-1) 烯烴樹脂（bl-3) 環狀烯烴 共聚物樹脂（bl-1) 聚酯樹脂⑷ 会畺 (質量％) g 〇 o § 種類 PET PET PET PET PET I PET I PET PET PET PET PET PET 比較例1 1 比較例2 比較例3 比較例4 比較例5 |比較例6 比較例7 比較例9 比較例10 比較例11 |比較例12 I 比較例13 201119839 寸« 製法 橫延伸 倍率 (倍） \〇 ν〇 ν〇 CO CT； ν〇 CO VD cn Ό VO Ό cn νο Μ V〇 Μ cn 延伸溫度 (0〇 s *—Η S Η S r—^ S S -Η S s ι—Η S S S S 1—^ S S _ι 縱延伸 倍率 (倍） VD ν〇 cn <τί ν〇 4 ν〇 (ΤΪ Ό cn \ο CO CO ν〇 ΓΟ Ό CO ν〇 CO νο Μ 紅外線加熱器 時間 (秒鐘） 0.72 0.72 0.72 0.72 1 0.72 0.72 0.72 0.72 '0.72 0.72 0.72 0.72 0.72 0.72 0.72 距離 (mm) ιη ο VO 輸出功率 (W/cm) ΙΟ m δ S 这 熱量Q (W/cm ) 12.6 οο οό 18.8 37.7 οο οο I-Η ι- 12.6 12.6 \〇 ι _ i 12.6 12.6 12.6 VD 1 1 ( 12.6 延伸前薄膜溫度 (°C) όο οο ν〇 οο ν〇 00 νο ΟΟ νο οο Ό οο νο οο VD οο ν〇 ΟΟ \D οο Ό οο ν〇 οο \〇 οο οο \ο 預熱輥溫度 (°C) Ο Ο ο ο ο ο ο ο Ο Ο Ο Ο Ο ο ο 實施例1 實施例2 實施例3 實施例4 實施例5 實施例6 實施例7 實施例8 實施例9 實施例10 實施例11 實施例12 實施例13 實施例14 實施例15 -9寸- 201119839 製法 橫延伸 倍率 (倍） VD v〇 CO v〇 v〇 oS v〇 CO Ό VD cn \D 延伸雛 (°C) s S s r—H s 1 ^ s s i 1 s * 1 H s S s S s 縱延伸 倍率 (倍） \〇 vo 3 V〇 Ό v〇 CO \D CO v〇 oS CO oS 紅外線加熱器 時間 (秒鐘） 0.72 0.72 0.72 , 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 距離 (mm) vn VO w-1 v〇 wo 輸出功率 (W/cm) 泛 w*> m 熱量Q (W/cm ) Η 12.6 V〇 c4 1 1 VO o4 VO o4 12.6 12.6 cs 12.6 37.7 oo od 12.6 延伸前薄膜溫度 (°C) 〇〇 〇〇 VO oo VO oo v〇 oo oo v〇 oo VD oo v〇 oo \〇 s On oo \〇 預熱輥溫度 (°C) Ο o o 〇 o o o o o s g o 實施例16 實施例17 實施例18 實施例19 實施例20 實施例21 實施例22 實施例23 實施例24 實施例25 實施例26 實施例27 _ Z,寸. 201119839 9« 製法 橫延伸 倍率 (倍） Μ cn cn VO <ri v〇 oS OO CN v〇 CO VO cn 延伸溫度 rc) s 1-Η S ^ Ή s t < s f _< s s l 1 s < »-H s s s s l 1 縱延伸 倍率 (倍） Ό \D Ό ΓΟ v〇 v〇 〇0 Ό oS Ό CO \D 〇\ CS [外線加熱器 時間 (秒鐘） 0.72 0.72 j 0.72 0.72 0.72 0.72 ! 0.72 0.72 0.72 0.72 0.72 0.72 距離 (mm) un 1-H Vi-l wn 輸出功率 (W/cm ) Ο un s i 1 s R R s 熱量Q (W/cm) Ο 00 40.2 CS 〇6 VO 12.6 12.6 1 12.6 12.6 CN CN od 12.6 延伸前薄膜猶 rc) οο ν〇 οο co \D oo 00 oo v〇 oo VO oo 00 Ό oo v〇 oo \o oo \〇 預熱輥溫度 (0〇 Ο ο 〇 〇 o o o o 〇 〇 o o 比較例1 比較例2 比較例3 比較例4 比較例5 比較例6 比較例7 比較例9 比較例10 比較例11 比較例12 比較例13 _oo寸— 201119839 表7 薄膜厚度 (βτη) 相對反射率 (%) 比重 凹陷之個數 (正面/背面） (個/100_2) 輥污染 製膜性 實施例1 188 100.8 A 0.90 S 0.2/0.2 S s 實施例2 188 100.7 A 0.89 S 0.8/0.8 A s 實施例3 188 100.9 A 0.91 A 0.0/0.0 S s 實施例4 188 100.1 A 0.99 A 0.0/0.0 S s 實施例5 188 100.3 A 0.97 A 0.0/0,0 S s 實施例6 188 101.1 S 0.84 S 0.6/0.6 A s 實施例7 188 101.0 S 0.90 s 0.3/0.3 A s 實施例8 188 100.5 A 1.00 A 0.1/0.1 S s 實施例9 188 101.0 S 0.82 S 0.3/0.3 A A 實施例10 188 100.5 A 0.85 S 0.2/0.2 S s 實施例11 188 100.4 B 1.00 A 0.1/0.1 S A 實施例12 188 101.0 S 0.85 S 0.3/0.3 s S 實施例13 188 100.8 S 0.88 s 0.2/0.2 s s 實施例14 188 101.2 s 0.81 s 0.2/0.2 s s 實施例15 188 101.1 S 0.83 s 0.3/0.3 s s -49- 201119839S = S' XEXNQ: heat reaching the film surface (per single-sided film) (W/cm); S: output power of the infrared heater to the film side (per single-sided film) (W/cm); L: from Distance from the infrared heater to the surface of the film (mm); S': rated output power per watt of infrared heater (W/cm) > E: irradiation efficiency; N: number of heaters per side of the film. B. Density in the presence of a depression on the surface of the film After the platinum-palladium was steamed on the surface of the film, it was enlarged by a field emission scanning electron microscope by 2,500 times to obtain a magnified image. The number of concave depressions having a length of 1/im or more in a 10 // m square is counted by the enlarged image. The same operation was performed for different 10 fields of view, and the average enthalpy was used as the existence density of the dent. The two sides of the film were measured as described above, and then the higher ones were used. The field emission scanning electron microscope was JSM-6700F manufactured by JEOL Ltd. C. Relative reflectance The light reflectance at 560 nm was measured by attaching a 0 60 integrating sphere and a 1° tilting locator to a spectrophotometer. Further, the 'light reflectance is measured on both sides of the white film', and the higher the number is used as the reflectance of the white film. The spectrophotometer is U-3410 manufactured by Hitachi, Ltd., 30-201119839 (Hitachi, Ltd.), and the 0 60 integrating sphere is 130-0632 manufactured by Hitachi, Ltd. (the inner surface is made of barium sulfate) 'Standard white plate is 2 1 0-0740 (aluminum oxide) manufactured by HUAcln Instruments Service Co., Ltd. The relative reflectance is judged at the following levels. If the result of the determination is S, A or B, it is qualified. If it is S or A, it is preferable. • The case where the relative reflectance is 101% or more and less than 120%: S; • The case where the relative reflectance is 100% or more and less than 101%: A; • The relative reflectance is 9 9 钇 or more and less than 1 0 0% of cases: B; • Relative reflectance is less than 99%: C * D. Specific gravity cuts the white film into 5 cm x 5 cm, and then according to the guidelines of JIS K7 1 1 2 (1 980 edition) The measurement was carried out using an electronic hydrometer. Further, five sheets of each of the white films were separately measured, and the average enthalpy was used as the specific gravity of the white film. The electronic hydrometer was SD-1 20L manufactured by Mirage Co., Ltd. The specific gravity is determined by the following levels. If the result of the determination is S, A or B, it is qualified. • The specific gravity is 〇. 5 5 or more and 〇. 9 or less: S; • The specific gravity is greater than 0.9 and 1.0 or less: A; • The specific gravity is greater than 1 · 0 and 1.3 or less: B; • The specific gravity is greater than 1.3 situation: C. E. Film-forming property Film-forming property was evaluated at the following grades by the frequency of film breakage during film formation -31 - 201119839. For mass production, the film forming properties of S, A or B are required. If it is S or A, there is a further cost reduction effect. Film ruptures are less than once a week: S; • Film ruptures are more than 2 times and less than 5 times a week: A; • Film ruptures 6 or 7 times a week: • The film ruptures more than 8 times a week: C. F. Contamination evaluation of the film production line In the longitudinally extending chill roll group in the film formation, after the film passes, the contamination is observed at the whole or the end of the film passing through the surface of any of the rolls. Evaluate the pollution of the film production line. When the contamination is observed, cleaning is required, and production cannot be performed during cleaning. Therefore, from the viewpoint of productivity, it is acceptable if it is S or A, and more preferably S 〇 • passes 50,000 meters. No pollution was observed afterwards: S; • Although no pollution was observed after passing 10,000 meters, pollution was observed after passing 50,000 meters: A; • After passing 2000 meters, although no pollution was observed, Contamination was observed after 10,000 m: B; • Contamination was observed after 2000 m: C» G. The glass transition temperature of the incompatible component (b) was obtained by separately obtaining the incompatible component (b) , which was obtained by melting and quenching 5 mg of the incompatible component (b) -32-201119839 Sample 'using a differential scanning calorimeter from 25 ° C at a rate of 2 (TC / min) The temperature is raised and the intermediate point glass transition temperature of the IST IS 7112C 1987 edition is taken as the glass transition temperature. The differential scanning calorimeter was a DSC-2 type manufactured by Perkin Elmer, Inc. Further, in the case where the incompatible component (b) cannot be obtained alone, the glass transition temperature is measured using a differential scanning calorimeter after the incompatible component (b) is separated from the white film. For example, in the case of a white film composed of a polyester resin (a1), a cyclic olefin copolymer which is an incompatible thermoplastic resin (b1), and inorganic particles (b2), a white film is dissolved in The undissolved matter of a mixed solution of methanol and chloroform having a volume fraction of 1:1 was filtered and taken out. The undissolved matter was redissolved in chloroform, and the undissolved matter was taken out and dissolved in a mixed solution of hexafluoroisopropanol and chloroform having a volume fraction of 1:1. After the solution is centrifuged in a centrifugal separator, a cyclic olefin copolymer can be obtained by taking a float. A sample obtained by melting and quenching 5 mg of the cyclic olefin copolymer obtained as described above was heated from 25 ° C at a temperature increase rate of 20 ° C / min using a differential scanning calorimeter, and JIS was added. The intermediate point glass transition temperature of the K7 1 2 1 (1 987 edition) guideline can be determined as the glass transition temperature. The differential scanning calorimeter is, for example, a D S C - 2 type manufactured by Bojing Instruments. H. Film temperature before stretching The longitudinal stretching ratio in the film forming conditions was set to 1.0 times, and the heating using the infrared heater was stopped. The film temperature of the extension of the longitudinal extension was measured using a radiation temperature measurement of -33 - 201119839, and the film temperature of the film was extended by the average enthalpy. At this time, the emissivity correction of the film of the target is performed in advance. The radiation thermometer is an IT2-80R manufactured by Keyence Corporation. [Embodiment] Hereinafter, the present invention will be more specifically described with reference to the embodiments, but the present invention is not limited thereto. (Materials) • Polyester resin (al-Ι) The acid component is terephthalic acid, the glycol component is ethylene glycol', and antimony trioxide (polymerization catalyst) is added to the obtained polyester. The pellet was subjected to a polycondensation reaction in a molar ratio of 300 ppm to obtain a polyethylene terephthalate (PET) having an ultimate viscosity of 0.63 dl/g and a carboxyl terminal group of 40 equivalent/ton. When the crystal melting heat was measured by using a differential thermal analyzer, it was 1 cal/g or more, which is a crystalline polyester resin. The melting point Tm of the resin was measured and found to be 25 °C. • The cyclic olefin copolymer resin (bl-1) was a cyclic olefin resin "TOPAS" (manufactured by Polyplastics Co., Ltd.) having a glass transition temperature of 178 ° C and an MVR (260 ° C / 2.16 kg) of 4.5 ml / 10 min. Further, when the heat of crystal fusion was measured by using a differential thermal analyzer, it was less than 1 cal/g, which was an amorphous resin. Cyclic olefin copolymer resin (bl-2) -34- 201119839 A cyclic olefin resin "TOPAS" (Polyplastics) with a glass transition temperature of 158 ° C and an MVR (260 ° C / 2.16 kg) of 4.5 ml / 10 min Made by the company). Further, when the heat of crystal fusion was measured by using a differential thermal analyzer, it was less than 1 cal/g, which was an amorphous resin. • Olefin resin (bl-3) olefin resin PMP (polymethylpentene) with a glass transition temperature of 25 ° C and a melting point of 235 ° C ' MFR ( 260 ° C/5 kg) of 8 g/10 min TPX" (manufactured by Mitsui Chemicals, Inc.). • Copolymerized polyester resin (c-1) Copolymerized PET using CHDM (cyclohexanedimethanol). The resin is a PET obtained by copolymerizing 30 mol% of cycloheximide dimethanol in a copolymerized diol component. The result of measuring the heat of crystal melting using a differential thermal analyzer is less than 1 cal/g, which is an amorphous resin. • Copolymerized polyester resin (c-2) Copolymerized PET using CHDM (cyclohexanedimethanol). The resin is a PET obtained by copolymerizing a copolymerized diol component with 60 mol% of cyclohexanedimethanol. The result of measuring the heat of crystal melting using a differential thermal analyzer is less than 1 cal/g, which is an amorphous resin. • Copolymerized polyester resin (c-3) Copolymerized PET with isophthalic acid. The resin is PET obtained by copolymerizing a copolymerized dicarboxylic acid component with 17·5 mol% of phthalic acid. The result of measuring the heat of crystal melting by using a differential thermal analyzer is -35 - 201119839 and less than 1 cal/g, which is an amorphous resin. • Dispersant (d-1) uses a PBT-PAG (poly-extension-based diol) copolymer. The resin is a block copolymer of PBT (polybutylene terephthalate) and PAG (mainly polytetramethylene glycol). When the calorific value of the crystal was measured by a differential thermal analyzer, it was 1 cal/g or more, which is a crystalline resin. [Example 1] A mixture of the raw materials as shown in Table 1 was vacuum dried at 180 ° C for 3 hours and then supplied to an extruder. After melt extrusion at a temperature of 280 ° C, it was filtered through a 30 /Z m cut filter and then introduced into a T-die. Next, it was extruded into a sheet shape from a T-die as a molten single layer sheet. The molten single-layer sheet was held on a drum at a surface temperature of 25 ° C, and electrostatically applied to adhere to a cooling and solidification to obtain an unstretched single-layer film. At this time, it is assumed that the film surface attached to the drum is the back surface and the surface connected to the air is the front surface. Next, the unstretched single-layer film was preheated by a roll group heated to a temperature of 85 ° C, and then irradiated from both sides of the film under the conditions of an infrared heater as shown in Table 4, while using the peripheral speed difference of the roll toward the film. The length direction was extended by 3.6 times, and then cooled by a roll group having a temperature of 25 ° C to obtain a uniaxially stretched film. The infrared heater is a pure carbon heater "CZB8000/1000G" manufactured by Heraeus Co., Ltd. and is arranged on both sides with two sides on one side. The heater is a heater with a length of 1 m and a rated output power of 80 W/cm per one. Further, the power supplied to the heater was adjusted to meet the conditions of the infrared heater shown in Table 4. In addition, the number of heating conditions, such as the one shown in the table -36-201119839, is the number per one side. While holding both ends of the obtained uniaxially stretched film with a cooker, the film is introduced into a preheating zone at a tenter temperature of 95 ° C, and secondly, continuously heated at a temperature of 105 ° C toward the film. The direction in which the longitudinal directions are orthogonal (film width direction) is extended by 3.6 times. Then, heat treatment is applied to the heat treatment zone in the tenter at 190 ° C for 20 seconds, and further, after the relaxation treatment is applied to the 6% width direction at a temperature of 180 ° C, and then at a temperature of 140 ° C toward 1 The relaxation treatment is applied in the % width direction. Secondly, the sentence is slowly cooled and then taken up. A single-layer white film having a thickness of 1 88 β m can be obtained as described above. As a result of observing the cross section of the white film, many fine bubbles were contained inside. Further, the number of depressions on the surface of the film is small, and there is no roll contamination and excellent film formability. The various characteristics of the film are shown in Table 7. [Examples 2 to 7] Film formation was carried out in the same manner as in Example 1 except that the conditions of the infrared heaters shown in Table 4 were respectively set to obtain a single-layer white film having a thickness of 188 / zm. It was observed that the cross-sectional result of the white film contained many fine bubbles inside. Further, the number of depressions on the surface of the film is small, and there is no roll contamination and the film formability is also excellent. The various characteristics of the film are shown in Table 7. [Examples 8 to 15, 17, 22 to 24] Film formation was carried out in the same manner as in Example 1 except that the raw material compositions shown in Tables 1 and 2 were respectively set to obtain a thickness of 1 88 / /m single layer white film. It was observed that the cross-section result of the white film -37-201119839 ' contained a lot of fine bubbles inside. Further, the number of depressions on the surface of the film is small, the roll contamination is small, and the film formability is also excellent. The various characteristics of the film are shown in Tables 7 and 8. [Example 1 6] A mixture of the raw materials as shown in Table 2 was vacuum dried at 180 ° C for 3 hours and then supplied to an extruder (A). Further, the polyester resin (a 1 -1 ) was additionally dried at a temperature of 180 ° C for 3 hours and then supplied to an extruder (B). The raw material supplied to the extruder (A) and the raw material supplied to the extruder (B) are separately melted at a temperature of 28 (TC) and supplied to a feed tap block. Then, the layer (layer A) composed of the raw material supplied to the extruder (A) and the layer (layer B) composed of the raw material supplied to the extruder (B) are laminated in the thickness direction to form the layer A. The second layer of the layer is laminated and then introduced into the T-die. Next, it is extruded into a sheet shape from the T-die to form a molten two-layer laminated unstretched sheet composed of the A layer/B layer. The molten laminated sheet is held in On the drum with a surface temperature of 25 °C, it is electrostatically fixed to be cooled and solidified to obtain an unstretched laminated film. At this time, the surface of the layer B is connected to the drum and the surface of the layer A is connected to the air. The surface of the layer B is the front surface and the surface of the layer A is the front surface. Next, after the unrolled film is preheated by a roll group heated to a temperature of 85 ° C, the conditions of the infrared heater as shown in Table 5 are only Irradiation on the surface side (front side) of layer A, while proceeding toward the length of the film by the circumferential speed difference of the rolls 3.6 times extension, and cooled by a roll group at a temperature of 25 ° C, -38- 201119839 to obtain a uniaxially stretched film. One side of the obtained uniaxially stretched film is held by a cooker, one side It is introduced into a preheating zone at a tenter temperature of 95 ° C, and then continuously extended in a direction orthogonal to the longitudinal direction of the film (film width direction) by 3.6 times in a heating zone at a temperature of 105 ° C. Then, heat treatment is applied in the heat treatment zone in the tenter at 190 ° C for 20 seconds, and further, at 180 ° C, the relaxation treatment is applied to the 6% width direction, and then at 140 ° C to the 1 % width. The direction is applied with a relaxation treatment. Secondly, it is uniformly cooled slowly and then taken up. A laminated white film having a thickness of 1 8 8 // m can be obtained as described above. The cross-sectional result of the white film is observed to have many inside the layer A. Further, the front and back surfaces have a small number of depressions on the surface of the film, no roll contamination, and excellent film formability. Various characteristics of the film are shown in Table 8. [Examples 18 to 21, 27] Except as set separately as shown in Table 5 Other than the stretching ratio, etc., the film formation was carried out in the same manner as in Example 1 to obtain a single-layer white film having a thickness of 1 8 8 " m. The cross-section of the white film was observed to have many fine contents inside. In addition, the number of depressions on the surface of the film is small, the roll contamination is small, and the film formation property is also excellent. The various characteristics of the film are shown in Table 8. [Examples 25 and 26] are set as shown in Table 5, respectively. The preheating roll temperature and the infrared heater conditions were the same, and the rest was formed in the same manner as in Example 1 to obtain a single-layer white film having a thickness of 188 #m. It was observed that the white thin-39-201119839 film cross section was observed. The result 'has a lot of fine bubbles inside. Further, the number of depressions on the surface of the film is small, and the roll contamination is small and the film formability is also excellent. The various characteristics of the film are shown in Table 8. [Comparative Examples 1, 2, and 4] Film formation was carried out in the same manner as in Example 1 except that the conditions of the infrared heater shown in Table 6 were respectively set to obtain a single layer having a thickness of 188/zm. White film. The film forming property was inferior to that of Example 1. As a result of observing the cross section of the white film, fine bubbles were contained inside. Since the heat Q is less than 8.5 W/cm, the temperature of the surface of the film cannot be sufficiently increased, so that the number of depressions on the surface of the film is increased. Therefore, there is also a lot of roller contamination. As a result, frequent cleaning is required. The various properties of the film are shown in Table 9. [Comparative Example 3] Film formation was carried out in the same manner as in Example 1 except that the conditions of the infrared heater shown in Table 6 were set. Since the heat Q exceeds 40 W/cm ', when the longitudinal direction (longitudinal direction) is extended, the film is softened and the film is thermally sag, resulting in failure to form a film. [Comparative Example 5] #7 The film was formed in the same manner as in the case of the infrared heater shown in Table 6, in the same manner as in the #M U stomach Example 166, to obtain a laminated white film having a thickness of 1 88. The film forming property was repeatedly broken and was inferior to that of Example 16. As a result of observing the cross section of the white film, fine bubbles were contained inside the layer composed of the mixed raw materials as shown in Table 3. Since the temperature of the film surface of Q-2011-19839 is less than 8.5 W/cm', the temperature of the film surface cannot be sufficiently increased, so that the number of depressions on the surface of the film is increased. Therefore, the roll is contaminated, resulting in frequent cleaning. The various characteristics of the film are shown in Table 9. [Comparative Example 6] A film was formed in the same manner as in Example 1 except that the raw material composition was as shown in Table 3, and a single-layer transparent film having a thickness of 188 #m was obtained. When extending in the longitudinal direction, the edge portion is thermally swelled, so that the width of the film after the longitudinal stretching is varied, so that a film having a large thickness unevenness is obtained. Since there is no incompatible component, there is no roll contamination. However, since there is no air bubble inside the film and the reflectance is small, it is not suitable as a film of a reflective film. The various characteristics of the film are shown in Table 9. [Comparative Examples 7 and 1 2] Film formation was carried out in the same manner as in Example 1 except that the raw material composition was as shown in Table 3, respectively, to obtain a single-layer white film having a thickness of 丨88 #m. Comparative Example 7 is a cross-sectional result of observing a white film. Film formation is unstable and cracks occur repeatedly. Comparative Example 12 is a cross-sectional result of observing a white film, and contained fine bubbles inside. Since the heat Q is less than 8.5 W/cm, the temperature of the surface of the film cannot be sufficiently raised, so that the number of depressions on the surface of the film is increased. As a result, the roll is also contaminated. As a result, frequent cleaning is required. The various characteristics of the film are shown in Table 9. [Comparative Examples 9 to 1 1 and 1 3] -41 - 201119839 Film formation was carried out in the same manner as in Example 1 except that the stretching ratios as shown in Table 6 were respectively set to obtain a thickness of 1 8 8 # m single layer white film. As a result of observing the cross section of the white film, many fine bubbles were contained inside. In Comparative Example 9, the stretching ratio in the longitudinal direction of the film was more than 4.5 times, and in Comparative Example 11, the stretching ratio in the film width direction was more than 5 times, so that the number of depressions on the surface of the film was increased. Therefore, the roll is contaminated, resulting in frequent cleaning. In Comparative Example 10, the stretching ratio in the film width direction was less than 3 times, and in Comparative Example 13, the stretching ratio in the film width direction was less than 2.9 times, so that the number of depressions on the surface of the film was small and the contamination of the roll was small. However, the reflectance is small, so it is not suitable for use as a film of a reflective film. Further, Comparative Example 13 is prone to cracking when it is laterally extended. The various characteristics of the film are shown in Table 9. -42- 201119839 ι撇4 ii ϋ Other Ingredients/-S ^13⁄4 'Sw〆to VO P /"s 承 — Ο ώ X Xm ul /-N ^ CN Ο ώ 〇H v〇pg l/~j CJ ΜΪ 1 /-~N p si /―s Φ 班 /-N 2 'w rfJ Μ per 壊 (ff%) m JO <n 〇un Ό & 氧化 Oxidation of titanium oxide titanium oxide titanium oxide _1 titanium oxide駄 駄 駄 駄 氧化钛 氧化钛 氧化钛 氧化钛 氧化钛 氧化钛 氧化钛 / Ν Ν Ν Ν Ν Ν -1 -1 -1 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘 刘In Sec) 00 1 i oo 〇〇1 1 〇〇OO oo H 00 1 < oo OO oo ( oo oo r—< 00 1 1 oo 00 1 Ή 骚 tisIS ι1πΠΐ P ^Sffbl-1) /~s I 1 1 劲 5 love am 1 stupid N +5 light flm heart an i| /•~N »-Η 1 wing 5 ll m ίΚ /-N i 1 wing 5 sac flm: a>c〇3 il m H 1 System 5 meal ship il m « 1 wing 5 love iJm nm taste copolymer iSffbl-1) <-1 1 «5 install am heart tCQ _ 1 copolymer S1fEl-l) r-\ 1 < 1 Jin 5 late inn 4^ Tu3 is armor ( /—N wing 5 love am J> C〇3 il age 1 1 1 a5 light am iL^〇33 11 age se love am A-^noa 11 m wipe polyester resin U1) Quantity (% by mass) gg § JO VQ to type PET PET PET PET PET PET PET PET PET PET PET PET PET PET PET Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 _ ε inch — 201119839 1 Film composition Other components 畺 (% by mass) cn 1 Isophthalic acid 17.5 mol% Copolymerized PET (c-3) Incompatible components (8) Inorganic particles (b2) Content (% by mass) VO Ο VO Type barium sulfate titanium oxide titanium oxide titanium oxide titanium oxide titanium oxide titanium oxide titanium oxide titanium oxide ^1 m Π35 m ψί 暑 ( 质量 质量 s 玻璃 玻璃 玻璃 玻璃 玻璃 玻璃 玻璃 玻璃Oo 00 1 < oo Liu & irk m ^Is w cyclic olefin copolymer resin (bl-l) cyclic olefin copolymer resin (bl-l) cyclic olefin copolymer resin (bl-l) cyclic olefin Copolymer resin (bl-1) cyclic olefin copolymer tree (bl-l) cyclic olefin copolymer resin (bl-1) cyclic olefin copolymer resin (bl-2) olefin resin (bl-3.) cyclic olefin copolymer resin (bl-1) cyclic olefin copolymerization Resin (bl-l) cyclic olefin copolymer resin (bl-l) polyester resin (4) content (% by mass) o § § § s t1nn<P PET PET PET PET PET PET PET PET I PET I PET 1 i PET PET Example 16 Example 17 Example 18 Example 19 Example 20 Example 21 Example 22 Example 23 | Example 24 Example 25 Example 26 Example 27 - inch inch - 201119839 e嗽1 film composition of other components (% by mass) CO P isophthalic acid 17.5 mol% Copolymerized PET (c-3) Incompatible component (8) Inorganic particles (b2) Content (% by mass) VO to ο υ-1 Sao>1mi1 w Oxidation of titanium oxide Titanium titanium oxide, titanium oxide, barium sulfate, titanium oxide, titanium oxide, titanium oxide, titanium oxide, titanium oxide, thermoplastic resin (bl), content (% by mass) VO un VO CN to VO ο glass transition temperature rc) 〇〇oo 1 oo »—H 00 1 1 OO oo oo OO wn CN 00 1 < species Cyclic olefin copolymer resin (bl-1) Olefin copolymer resin (bl-1) Cyclic olefin copolymer resin (bl-1) Cyclic olefin copolymer resin (bl-1) Cyclic olefin copolymer resin (bl-1) cyclic olefin copolymer resin (bl-1) cyclic olefin copolymer resin (bl-1) olefin copolymer resin (bl-1) olefin resin (bl-3) cyclic olefin copolymer resin (bl-1) Polyester Resin (4) Meeting (% by mass) g 〇o § Type PET PET PET PET PET I PET I PET PET PET PET PET Comparative Example 1 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 |Comparative Example 6 Comparative Example 7 Comparative Example 9 Comparative Example 10 Comparative Example 11 | Comparative Example 12 I Comparative Example 13 201119839 Inch « Manufacturing method Horizontal stretching ratio (times) \〇ν〇ν〇CO CT; ν〇CO VD cn Ό VO Ό cn νο Μ V〇Μ cn Extension temperature (0〇s *—Η S Η S r—^ SS -Η S s ι—Η SSSS 1—^ SS _ι Longitudinal extension ratio (times) VD ν〇cn <τί 〇〇4 ν〇(ΤΪ cn cn \ο CO CO ν〇ΓΟ Ό CO ν〇CO νο Μ Infrared heater time (seconds) 0.72 0.72 0.72 0. 72 1 0.72 0.72 0.72 0.72 '0.72 0.72 0.72 0.72 0.72 0.72 0.72 Distance (mm) ιη ο VO Output power (W/cm) ΙΟ m δ S This heat Q (W/cm) 12.6 οο οό 18.8 37.7 οο οο I-Η Ι- 12.6 12.6 \〇ι _ i 12.6 12.6 12.6 VD 1 1 ( 12.6 film temperature before extension (°C) όο οο ν〇οο ν〇00 νο ΟΟ νο οο Ό οο νο οο VD οο ν〇ΟΟ \D οο Ό Οο ν〇οο \〇οο οο ο Preheating roll temperature (°C) Ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο ο 6 Embodiment 7 Embodiment 8 Embodiment 9 Embodiment 10 Embodiment 11 Embodiment 12 Embodiment 13 Embodiment 14 Example 15 -9 inch - 201119839 Method horizontal extension magnification (times) VD v〇CO v〇v〇oS v 〇CO Ό VD cn \D extension chick (°C) s S sr—H s 1 ^ ssi 1 s * 1 H s S s S s Longitudinal extension ratio (times) \〇vo 3 V〇Ό v〇CO \D CO v〇oS CO oS Infrared heater time (seconds) 0.72 0.72 0.72 , 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 0.72 Distance (mm) vn VO w-1 v〇wo Output power (W/cm) Pan w*> m Heat Q (W/cm) Η 12.6 V〇c4 1 1 VO o4 VO o4 12.6 12.6 cs 12.6 37.7 oo od 12.6 Pre-stretch film temperature (°C) 〇〇〇〇VO oo VO oo v〇oo oo v〇oo VD oo v〇oo \〇s On oo \〇Preheat roll temperature (°C) Ο oo 〇ooooosgo Example 16 Example 17 Example 18 Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 _ Z, inch. 201119839 9« Process transverse extension ratio (times) Μ cn Cn VO <ri v〇oS OO CN v〇CO VO cn Extension temperature rc) s 1-Η S ^ Ή st < sf _< ssl 1 s < »-H ssssl 1 Longitudinal extension ratio (times) Ό \ D Ό ΓΟ v〇v〇〇0 Ό oS Ό CO \D 〇\ CS [External heater time (seconds) 0.72 0.72 j 0.72 0.72 0.72 0.72 ! 0.72 0.72 0.72 0.72 0.72 0.72 Distance (mm) un 1-H Vi -l wn Output power (W/cm) Ο un si 1 s RR s Heat Q (W/cm) Ο 00 40.2 CS 〇6 VO 12.6 12.6 1 12.6 12.6 CN CN od 12.6 Film before extension犹 rc) οο ν〇οο co \D oo 00 oo v〇oo VO oo 00 Ό oo v〇oo \o oo \〇Preheating roll temperature (0〇Ο ο 〇〇oooo 〇〇oo Comparative example 1 Comparative example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 _oo inch - 201119839 Table 7 Film thickness (βτη) Relative reflectance (%) Specific gravity Number (front/back) (one/100_2) Roll contamination film forming Example 1 188 100.8 A 0.90 S 0.2/0.2 S s Example 2 188 100.7 A 0.89 S 0.8/0.8 A s Example 3 188 100.9 A 0.91 A 0.0/0.0 S s Example 4 188 100.1 A 0.99 A 0.0/0.0 S s Example 5 188 100.3 A 0.97 A 0.0/0,0 S s Example 6 188 101.1 S 0.84 S 0.6/0.6 A s Example 7 188 101.0 S 0.90 s 0.3/0.3 A s Example 8 188 100.5 A 1.00 A 0.1/0.1 S s Example 9 188 101.0 S 0.82 S 0.3/0.3 AA Example 10 188 100.5 A 0.85 S 0.2/0.2 S s Example 11 188 100.4 B 1.00 A 0.1/0.1 SA Example 12 188 101.0 S 0.85 S 0.3/0.3 s S Example 13 188 100.8 S 0.88 s 0.2/0.2 ss Example 14 188 101. 2 s 0.81 s 0.2/0.2 s s Example 15 188 101.1 S 0.83 s 0.3/0.3 s s -49- 201119839

表8 薄膜厚度 (Mm) 相對反射率 (%) 比重 凹陷之個數 (正面/背面） (個/100//m2) 輥污染 製膜性 實施例16 188 101.0 S 1.20 B 0.7/0.0 S S 實施例17 188 100.8 A 0.57 S 0.9/0.9 A B 實施例18 188 100.1 A 0.97 A 0.2/0.2 S S 實施例19 188 101.5 S 0.79 S 0.8/0,8 A B 實施例20 188 100.1 A 0.92 A 0.1/0.1 S S 實施例21 188 101.3 S 0.82 S 0,9/0.9 A B 實施例22 188 101.2 s 0,55 s 0.9/0.9 A B 實施例23 188 100.0 A 0.98 A 0.7/0.7 A A 實施例24 188 100.2 A 1,05 B 0.9/0.9 A A 實施例25 188 100.3 A 0.97 A 0.0/0.0 S B 實施例26 188 100.6 A 0.88 S 0.8/0.8 A A 實施例27 188 98.9 C 1.03 B 0.2/0.2 S B -50- 201119839 表9 薄膜厚度 (Aim) 相對反射率 (%) 比重 凹陷之個數 (正面僧面） (個/100 μ m2) 輥污染 製膜性 fch較例1 188 100.3 A 0.86 S 5.7/5.5 C B 比較例2 188 100.4 A 0.87 s 4.8/4.3 c B 比較例3 延fE 崎發生熱垂 ，無法製膜 C 比較例4 188 100.4 A 0.89 s 1.2/1.2 c A 比較例5 188 101.2 S 1.19 B 14.8/0.0 B C 比較例ό 188 9.2 C 1.35 C 0.0/0.0 ,S A 比較例7 188 100.8 A 0.50 1.5/1.5 B C 比較例9 188 100.9 A 0.75 s 1.3/13 C C t卜，較例1〇 188 98.7 c 1.02 B 0.2/0.2 s A 比較例η 188 100.9 A 0.80 s 1.2/1.2 C c 比較例口 188 100.3 A 1.01 B 9.7/8.5 c A 比較例13 188 97.5 c 1.10 B 0.2/0.2 s c 在表4至6中之項目「熱量Q(W/cm)」ΐ系薄膜每 單面之到達薄膜面的熱量° 在表4至6中之項目「紅外線加熱器/輸出功率（ W/cm )」係薄膜每單面之紅外線加熱器向薄膜側之輸出 功率。 在表4至6中之項目「紅外線加熱器/距離（mm ) 」係從紅外線加熱器至薄膜面之距離。 在表4至6中之項目「紅外線加熱器/時間（秒鐘） -51- .201119839 」係薄膜通過照射區所需要之時間。 〔產業上之利用可能性〕 根據本發明之白色薄膜之製造方法，則可提供一種 製膜性、白色性、反射性爲優異之白色薄膜。此外’藉 由使用本發明之白色薄膜，則可提供一種輝度特性優異 之面光源。 【圖式簡單說明】 第1圖是展示從薄膜寬度方向所觀察之熱量Q測定 方法示意圖。 【主要元件符號說明】 1 薄膜 2 熱電偶 3 熱源（紅外線加熱器） D 薄膜表面的受熱部分之薄膜長度方向長度（照 射區之薄膜長度方向長度）.. L 從熱源（紅外線加熱器）至薄膜表面之距離 -52-Table 8 Film Thickness (Mm) Relative Reflectance (%) Number of Specific Gravities (Front/Back) (1/100//m2) Roll Contamination Film Formation Example 16 188 101.0 S 1.20 B 0.7/0.0 SS Example 17 188 100.8 A 0.57 S 0.9/0.9 AB Example 18 188 100.1 A 0.97 A 0.2/0.2 SS Example 19 188 101.5 S 0.79 S 0.8/0,8 AB Example 20 188 100.1 A 0.92 A 0.1/0.1 SS Example 21 188 101.3 S 0.82 S 0,9/0.9 AB Example 22 188 101.2 s 0,55 s 0.9/0.9 AB Example 23 188 100.0 A 0.98 A 0.7/0.7 AA Example 24 188 100.2 A 1,05 B 0.9/ 0.9 AA Example 25 188 100.3 A 0.97 A 0.0/0.0 SB Example 26 188 100.6 A 0.88 S 0.8/0.8 AA Example 27 188 98.9 C 1.03 B 0.2/0.2 SB -50- 201119839 Table 9 Film Thickness (Aim) Relative Reflectance (%) Number of specific gravity depressions (front surface) (one/100 μ m2) Roller film-forming property fch Comparative Example 1 188 100.3 A 0.86 S 5.7/5.5 CB Comparative Example 2 188 100.4 A 0.87 s 4.8/ 4.3 c B Comparative Example 3 Delayed fE Stagnation occurs, film formation is not possible C Comparative Example 4 188 100.4 A 0.89 s 1.2/1.2 c A Comparative Example 5 188 101.2 S 1.19 B 14.8 /0.0 BC Comparative Example 188 9.2 C 1.35 C 0.0/0.0 ,SA Comparative Example 7 188 100.8 A 0.50 1.5/1.5 BC Comparative Example 9 188 100.9 A 0.75 s 1.3/13 CC t, Comparative Example 1〇188 98.7 c 1.02 B 0.2/0.2 s A Comparative Example η 188 100.9 A 0.80 s 1.2/1.2 C c Comparative Example Port 188 100.3 A 1.01 B 9.7/8.5 c A Comparative Example 13 188 97.5 c 1.10 B 0.2/0.2 sc In Tables 4 to 6 The item "heat Q (W/cm)" is the heat of the film on each side of the film. The items in "Infrared Heater / Output Power (W/cm)" are listed on each side of Tables 4 to 6. The output power of the infrared heater to the film side. The items "infrared heater / distance (mm)" in Tables 4 to 6 are the distance from the infrared heater to the film surface. In the items in Tables 4 to 6, "infrared heater / time (seconds) -51 - .201119839" is the time required for the film to pass through the irradiation zone. [Industrial Applicability] According to the method for producing a white film of the present invention, a white film excellent in film formability, whiteness, and reflectivity can be provided. Further, by using the white film of the present invention, it is possible to provide a surface light source excellent in luminance characteristics. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a method of measuring the amount of heat Q observed from the width direction of a film. [Description of main components] 1 Film 2 Thermocouple 3 Heat source (infrared heater) D Length of film length in the heated portion of the film surface (length of film length in the irradiation zone): L From heat source (infrared heater) to film Surface distance -52-

Claims (1)

.201119839 七、申請專利範圍： 1. 一種白色薄膜之製造方法，用於製造在內部具有氣泡 、比重爲0.55以上且1.30以下之白色薄膜，其係將具 有含有主要樹脂成分、與對該樹脂成分爲非相溶性成 分的層之薄膜，一邊將其至少一表面以每單面爲8.5 W/cm以上且40 W/cm以下之熱量加熱，一邊利用輥之 周速差而在薄膜長度方向延伸3.0倍以上且4.5倍以下 後，再在薄膜寬度方向延伸3倍以上且5倍以下。 2. 如申請專利範圍第1項之白色薄膜之製造方法，其中 該薄膜長度方向之延伸倍率爲3.4倍以上且4.5倍以下 〇 3. 如申請專利範圍第1或2項之白色薄膜之製造方法， 其中該主要樹脂成分之玻璃轉移溫度爲Tg(t)時， 施加預熱使得在薄膜長度方向延伸前之薄膜溫度爲在 Tg-20 ( °C )以上且 Tg (。(：）以下。 4. 如申請專利範圍第1至3項中任一項之白色薄膜之製 造方法’其中在該薄膜之至少一表面側設置紅外線加 熱器，且 設定由該薄膜表面至該紅外線加熱器之距離爲5 mm 以上且100 mm以下、 設定該薄膜每單面之該紅外線加熱器朝薄膜側之輸 出功率爲35 W/cm以上且150 W/cm以下，而 將該薄膜之表面以每單面爲8.5 W/cm以上且40 -53- 201119839 W/cm以下之熱量進行加熱。 5. 如申請專利範圍第1至4項中任一項之白色薄膜之製 造方法，其中該白色薄膜係具有含有聚酯樹脂、與對 該聚酯樹脂爲非相溶性成分之層，且該白色薄膜之至 少一側的最外層則爲該層， 該非相溶性成分是玻璃轉移溫度爲17〇°C以上且250 °C以下之熱塑性樹脂、及/或選自由氧化鈦、碳酸鈣及 硫酸鋇所組成的族群中之至少一種以上的無機粒子。 6. 如申請專利範圍第5項之白色薄膜之製造方法，其中 該非相溶性成分是玻璃轉移溫度爲170°C以上且25 0°C 以下之熱塑性樹脂、及選自由氧化鈦、碳酸鈣及硫酸 鋇所組成的族群中之至少一種以上的無機粒子。 7. 如申請專利範圍第5或6項之白色薄膜之製造方法， 其中相對於含有該聚酯樹脂與該非相溶性成分之層， 該無機粒子之含量爲5質量％以上且60質量％以下。 8. 如申請專利範圍第1至7項中任一項之白色薄膜之製 造方法，其中在該白色薄膜表面的凹陷之存在密度胃 1個/100y m2以下。 9. 如申請專利範圍第1至8項中任一項之白色薄膜之製 造方法，其中該白色薄膜之相對反射率爲1〇〇 %以上且 120%以下。 -54-.201119839 VII. Patent application scope: 1. A method for producing a white film for producing a white film having bubbles inside and having a specific gravity of 0.55 or more and 1.30 or less, which will have a main resin component and a resin component. The film of the layer of the incompatible component is heated at a distance of 8.5 W/cm or more and 40 W/cm or less per one surface of at least one surface thereof, and extends in the film length direction by the circumferential speed difference of the roll. After the ratio is more than 4.5 times or less, it is extended by 3 times or more and 5 times or less in the film width direction. 2. The method for producing a white film according to the first aspect of the invention, wherein the stretching ratio of the film in the longitudinal direction is 3.4 times or more and 4.5 times or less 〇 3. The method for producing a white film according to claim 1 or 2 When the glass transition temperature of the main resin component is Tg(t), preheating is applied so that the film temperature before extending in the longitudinal direction of the film is above Tg-20 (°C) and Tg (. (:) or less. 4 The method for producing a white film according to any one of claims 1 to 3, wherein an infrared heater is disposed on at least one surface side of the film, and a distance from the surface of the film to the infrared heater is set to 5 The output power of the infrared heater to the film side of each side of the film is 35 W/cm or more and 150 W/cm or less, and the surface of the film is 8.5 W per one side. The method for producing a white film according to any one of the above claims, wherein the white film has a polyester resin. ,versus The polyester resin is a layer of an incompatible component, and the outermost layer of at least one side of the white film is the layer, and the incompatible component is a thermoplastic having a glass transition temperature of 17 ° C or more and 250 ° C or less. a resin, and/or at least one or more inorganic particles selected from the group consisting of titanium oxide, calcium carbonate, and barium sulfate. 6. The method for producing a white film according to claim 5, wherein the incompatible component is The glass transition temperature is 170 ° C or more and 25 ° C or less of the thermoplastic resin, and at least one or more inorganic particles selected from the group consisting of titanium oxide, calcium carbonate, and barium sulfate. Or a method of producing a white film of the sixth aspect, wherein the content of the inorganic particles is 5% by mass or more and 60% by mass or less based on the layer containing the polyester resin and the incompatible component. The method for producing a white film according to any one of the items 7, wherein the depression of the surface of the white film is present in a density of 1/100 y m 2 or less. 9. If the application is in the range of items 1 to 8 The white film according to any one of the manufacturing method, wherein the relative reflectance of the white film 1〇〇% or more and 120% or less. -54-
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