201012834 九、發明說明 【發明所屬之技術領域】 本發明係關於一種可低成本製造之光學上均質性優異 的光學薄膜。 【先前技術】 手機、液晶電視等所使用的液晶顯示裝置，爲了補償 φ 起因於液晶的光學異向性之光學歪斜、顯示色依賴視覺方 向的性質，而使用相位差薄膜等光學薄膜。 於此等光學薄膜的材料，使用例如聚碳酸酯樹脂、環 狀烯烴聚合物等的合成樹脂，但此等合成樹脂的價格高。 作爲低價的樹脂所成的光學薄膜，例如特開昭60-24502 號公報的記載，已知丙烯-乙烯共聚物製薄膜所成的相位 差板。 但是’如特開昭60-24502號公報所記載之丙烯-乙烯 φ 共聚物製薄膜，相位差的不均勻大，有光學的均質性差之 問題，需要更進一步改良。 【發明內容】 本發明的目的在於提供可低價製造、光學的均質性佳 之光學薄膜。 本發明，其係具有來自1-丁烯的單體單位與來自丙 烯的單體單位之丙烯系共聚物’至少含有1層的藉由廣角 X射線繞射測定所求得之結晶晶格常數的a軸長度大於 -5- 201012834 6.70A，b軸長度大於21.5A之丙烯系共聚物爲主成份的 層。 【實施方式】 作爲本發明的光學薄膜之主成份所使用的樹脂，係具 有來自1-丁烯的單體單位與來自丙烯的單體單位之丙烯 系共聚物’藉由廣角X射線繞射測定所求得之結晶晶格 常數的a軸長度大於6.7〇A，b軸長度大於21.5A之丙烯 系共聚物。結晶晶格常數滿足前述條件之丙烯系共聚物爲 主成份之薄膜，變成光學的均質性佳者。 丙烯系共聚物的結晶晶格常數，係使用丙烯系共聚物 之壓膜，藉由廣角X射線繞射測定而可求得。具體地， 使用如以下的方法。 (1 )壓膜的製作 寬度lOOmmx長度lOOmmx厚度1mm的金屬框中，放 入9_0〜9.5g的丙烯系共聚物，23(TC下5分鐘預熱後，以 5分鐘從常壓升壓至 5. OMP a，保壓5分鐘。然後，於 3 〇°C冷卻5分鐘，製成厚度1mm的樣品。 (2)廣角X射線繞射測定 對以前述（1 )的方法所得之樣品，以下述的條件 測定廣角X射線繞射。 機種 理學（Rigaku)製 RINT2000 201012834 管球 Cu 電壓 50KV 電流 1 00mA 發散狹縫 (divergence slit) 1.0。 散射狹縫 (scatter slit) 1.0。 接收狹縫 (receiving slit ) 0.15 測定範圍 2 Θ ： 5 〜3 5 ° (3)結晶晶格常數的算出 所得的廣角X射線繞射光譜中，在繞射角20爲丨6. 〇 〜17.0°的區域，繞射峰強度顯示極大値之繞射角爲 20(。4〇)、在繞射角20爲12.5~15.〇。的區域，繞射峰強 度顯示極大値之繞射角爲20(11())。將0(。4())、θ(ΐΐβ)代入 下式d = i^/2Sin0 ( η=1，λ=1.54Α)的0，求得各結晶晶 格面間隔以下述式求得結晶晶格常數之^ φ 軸、a軸長度。 b軸長度=4d(〇4〇) a軸長度=b軸長度xd(11G)/(b軸長度2_d 2 1/2 • ^ ( 1 1 0)) 丙嫌系共聚物的結晶晶格常數’主要藉由與丙稀共聚 合之1-丁烯的共聚合比例而控制。通常隨含於丙烯系共 聚物之來自1-丁烯的單體單位的量變多，a軸長度 長度也變大。 本發明的丙烯系共聚物，係具有來自h 丁烯與丙烯 201012834 的單體單位之丙烯系共聚物。 作爲藉由廣角X射線繞射測定所求得之結晶晶格常 數的a軸長度大於6 7〇a，b軸長度大於21.5A之丙烯系 共聚物’例如由70〜97.5莫耳％之來自丙烯的單體單位 與2.5〜30莫耳％之來自丨_ 丁烯的單體單位所成之丙烯_ 1-丁嫌無規共聚物（但該丙烯-1-丁烯無規共聚物所含之 來自丙稀的單體單位與來自1-丁烯的單體單位之合計爲 0 100 莫耳％ )。 丙稀-1-丁烯無規共聚物中來自丨_ 丁烯的單體單位之 含量’從使用該共聚物所得之光學的均質性的觀點，較理 想爲2.5莫耳％以上，更理想爲1〇莫耳％以上，更加理 想爲18莫耳％以上。而且，於丨_丁烯的含量多的情況， 因容易產生顆粒的互相黏著’從操作的觀點，較理想爲 3〇莫耳％以下’更理想爲25莫耳％以下，更加理想爲22 莫耳％以下。 ® 本發明之丙烯系共聚物，也可含有來自丙烯與1-丁 嫌以外的單體之單體單位。作爲如此的單體，例如乙烯、 . 碳原子數5〜10的烯烴、聚烯化合物、環狀烯烴、乙 煉基芳香族化合物等。作爲前述烯烴例如1-戊烯、1_ 己烯、1-庚烯、1-辛烯、丨·壬烯、癸烯等直鏈狀α •烯烴 、3-甲基_1_ 丁烯、3_甲基_丨·戊烯、4_甲基_丨戊烯、2乙 基1-己稀、2,2,4 -二甲基_1_戊嫌等分支狀α_烯烴等。丙 烯系共聚物之來自丙烯與丁烯以外的單體之單體單位 的含量，通常爲20莫耳％以下，較理想爲1〇莫耳％以下 -8 - 201012834 本發明之丙烯系共聚物，根據ns Κ 7122之差示掃 描熱量測定中，具有於-50〜200°C被觀察之結晶的熔解熱 量爲IJ/g以上的結晶熔解峰，或結晶化熱量爲lJ/g以上 的結晶化峰之聚合物較理想，更理想爲具有30 J/g以上的 結晶溶解峰與30J/g以上的結晶化峰的兩波峰之共聚物。 於顯示如此的熱反應之共聚物的情況，即使於液晶電視等 φ 長時間加溫的條件下使用，成爲不易收縮、光學品質不易 降低之薄膜。 作爲本發明的光學薄膜之主成份所使用的丙烯系共聚 物之立體規則性，較理想爲具有整規（isotactic )構造或 間規（syndiotactic )構造爲主之聚合物。 本發明所使用的丙烯系共聚物之MFR，從加工性的 觀點，以0.1〜20g/10分較理想，更理想爲2〜20。而且 ，MFR係根據JIS K7210，於溫度230°C，負載21.18N下 @ 測定。 本發明的光學薄膜之主成份所使用的丙烯系共聚物， 例如使用戚格勒-納他（Ziegler-Natta )型觸媒、含有週 期表第4族〜第6族之過渡金屬化合物之觸媒或二茂金屬 (metallocene)觸媒，使丙烯與1-丁烯及依需要再追加 使用的單體共聚合之方法而製造。作爲戚格勒-納他（ Ziegler-Natta)型觸媒，例如含有鈦之固體狀過渡金屬成 份與含有有機金屬成份之觸媒等，作爲二茂金屬（ metallocene )觸媒，例如具有至少1個之環戊二烯形陰離 201012834 子骨架之含有週期表第4族〜第6族之過渡金屬化合物之 觸媒等。 作爲聚合方法’例如漿體聚合法、氣相聚合法、整體 聚合法、溶液聚合法等。此等聚合方法，可適用單獨使用 之一段聚合法或組合此等聚合法之多段聚合法。 本發明的光學薄膜’至少含有1層的前述丙烯系共聚 物爲主成份的層。此處，前述丙烯系共聚物爲主成份的層 ’係丙烯系共聚物的含量超過50重量％，70重量％以上 較理想’ 90重量％以上更理想，95重量％以上更加理想 ’ 1〇〇重量％最理想。 於本發明的光學薄膜’前述丙烯系共聚物爲主成份的 層’在無損本發明的效果之範圍，依據需要，也可含有前 述丙烯系共聚物以外的聚烯烴系樹脂、改性聚烯烴系樹脂 、松香系樹脂、聚萜烯（terpene )系樹脂、合成石油樹脂 、香豆酮（coumarone )系樹脂、酚系樹脂、二甲苯系樹 φ 脂 '異戊二烯系樹脂等其他樹脂。 作爲丙烯系共聚物以外的聚烯烴系樹脂，例如丙烯單 獨聚合物、丙烯與乙烯及選自碳原子數5〜20的α-烯烴 所成群之1種以上的烯烴之共聚物、乙烯單獨聚合物、乙 稀與碳原子數3〜20的烯烴之共聚物等。 作爲改性聚烯烴系樹脂，例如以順丁烯二酸酐、順丁 燃二酸二甲酯、順丁烯二酸二乙酯、丙烯酸、甲基丙烯酸 ' 23ft酞酸、甲基丙烯酸縮水甘油酯、甲基丙烯酸羥基乙 等改性劑改性之聚烯烴系樹脂。此處，在改性使用的聚 201012834 烯烴系樹脂，可爲習知的聚烯烴，例如乙烯系樹脂、整規 聚丙烯、間規聚丙烯、含共單體之無規型聚丙稀、藉由多 段聚合之嵌段型聚丙烯、聚（4-甲基-戊烯）、聚（1_丁 烯）等。 作爲松香系樹脂，例如天然松香、聚合松香、部份氮 化松香、完全氫化松香、此等松香的酯化物（例如甘油酯 、季戊四醇酯、乙二醇酯、甲酯）、松香衍生物（例如不 φ 均化松香、酞酸化松香、石灰化松香）。 作爲聚萜烯系樹脂’例如α -薇烯、$ -蒎綠、二戊嫌 等環狀萜烯的單獨聚合物、環狀萜烯的共聚物、環狀萌烯 與酚、雙酚等酚系化合物的共聚物（例如α-璇烯-酚樹脂 、二戊烯-酚樹脂、萜烯-雙酚樹脂等的萜烯-雙酚系樹脂 )、環狀萜烯與芳香族單體的共聚物之芳香族改性萜烯樹 脂。 作爲合成石油樹脂，例如石腦油分解油的c5餾分、 Φ (^〜（：^餾分及其他烯烴系餾分的單獨聚合物、共聚物、 此等單獨聚合物、共聚物的氫化物之脂肪族系石油樹脂、 芳香族系石油樹脂、脂環式系石油樹脂、脂肪族·脂環式 共聚物。作爲合成石油樹脂，又例如上述石腦油分解油與 上述萜烯之共聚物、該共聚物的氫化物之共聚合系石油樹 脂。 作爲石腦油分解油的較理想C5餾分，例如異戊二嫌 、環戊二烯、1，3-戊二烯、2-甲基-卜丁烯、2-甲基-2-丁烯 等甲基丁烯類、卜戊烯、2-戊烯等戊烯類、二環戊二烯。 -11 - 201012834 作爲c6〜Cu餾分，較理想爲茚（indene)、苯乙烯、鄰-乙烯基甲苯、間-乙烯基甲苯、對-乙烯基甲苯、Ct -甲基 苯乙烯、甲基苯乙烯等甲基苯乙烯類、甲基茚、乙基 茚、乙烯基二甲苯、丙烯基苯。作爲其他烯烴系餾分，較 理想爲丁烯、己烯、庚烯、辛烯、丁二烯、辛二烯。 作爲香豆酮系樹脂，例如香豆酮的單獨聚合物或香豆 酮與茚的共聚物等。 φ 作爲酚系樹脂，例如烷基酚樹脂、藉由烷基酚與乙炔 的縮合之烷基酚-乙炔樹脂以及此等樹脂的改性物。此處 ，作爲此等酚系樹脂，可爲酚以酸觸媒而羥甲基化之酚醛 樹脂型樹脂、以鹼觸媒而羥甲基化之甲酚型樹脂的任一者 〇 作爲二甲苯系樹脂，例如間-二甲苯與甲醛所成的二 甲苯-甲醛樹脂、使其與第3成份反應所得之改性樹脂。 作爲異戊二烯系樹脂，例如異戊二烯的二聚物之C10 φ 脂環式化合物與C1()鏈狀化合物共聚合所得的樹脂。 於丙烯系共聚物與其他樹脂混合的情況，與前述丙烯 系共聚物混練時’使用不使該丙烯系共聚物的結晶晶格常 數改變之樹脂較理想。亦即，相溶於丙烯系共聚物的非結 晶部份之樹脂較理想。 本發明的光學薄膜’在無損發明的效果之範圍，可添 加抗氧化劑、造核劑、潤滑劑、帶電防止劑等的添加劑。 作爲本發明的光學薄膜之製造方法，例如溶劑鑄膜法 、擠出成形法。前者的方法，係將熱塑性樹脂溶解於有機 -12- 201012834 溶劑之溶液，在具有離型性之二軸延伸聚酯薄膜等的基材 上’藉由模具塗佈法澆鑄後，進行乾燥，除去有機溶劑而 在基材上形成薄膜之方法。以如此的方法在基材上形成之 薄膜，從基材剝離後使用。作爲擠出成形法，例如吹塑法 、T模頭法、壓延法等。從製造成本的觀點，擠出成形法 較理想，特別從光學的均質性的觀點，T模頭法較理想。 本發明的光學薄膜可以T模頭擠出成形法製造，作爲 φ 使從T模頭擠出之熔融體冷卻固化之方法，例如使用澆鑄 輥與空氣腔而冷卻之方法、藉由澆鑄輥與接觸輥之挾壓的 方法、澆鑄輥與使該澆鑄輥沿其圓周方向壓接而設置之金 屬製無接縫皮帶間挾壓之方法、使用澆鑄輥與靜電釘扎之 冷卻方法等。於冷卻使用澆鑄輥的情況，爲了得到透明性 更佳的相位差薄膜，所使用的澆鑄輥之表面溫度爲-10〜 3 0 °C較理想。 於藉由澆鑄輥與接觸輥之挾壓的方法製造薄膜的情況 φ ，作爲接觸輥，使用橡膠輥或具有可彈性變形之金屬製無 接縫皮帶所成的外筒與該外筒的內部是由可彈性變形之彈 性體所成的輥且前述外筒與彈性體輥間充滿溫度調節用媒 體所成的構造之輥，由於可得配向小、光學的均質性佳之 薄膜，所以較理想。 於使用橡膠輥作爲接觸輥的情況，爲了得到具有鏡面 狀的光學薄膜，由T模頭擠出的熔融體，在澆鑄輥與橡膠 輥間與支持體一起挾壓較理想。作爲支持體，以厚度5〜 50 /z m的熱塑性樹脂所成的二軸延伸薄膜較理想。 -13- 201012834 於澆鑄輥與使該澆鑄輥沿其圓周方向壓接而設置之金 屬製無接縫皮帶間挾壓之方法使薄膜成形的情況，前述無 接縫皮帶，於澆鑄輥的圓周方向上，藉由平行該澆鑄輥而 配置之複數輥保持較理想。更理想爲無接縫皮帶以直徑 100〜30〇mm的二個輥保持，無接縫皮帶的厚度爲100〜 500 ju m。 以前述的方法所得之本發明的光學薄膜，因配向極小 φ 、光學的均質性佳，適合於例如偏光子保護薄膜等。而且 ，如此的薄膜藉由在至少一方向延伸，可適合使用作爲相 位差薄膜。以下，製造相位差薄膜時所使用的延伸前薄膜 ，稱爲原料薄膜。作爲原料薄膜，使用面內相位差爲 50nm以下的薄膜較理想。爲了使所得的薄膜之面內相位 差爲5 Onm以下，於使由T模頭擠出之熔融狀薄片冷卻固 化之步驟，必須不使儲存所（bank )(樹脂積存）生成。 儲存所（bank )係指熔融狀薄片在澆鑄輥與接觸輥間、澆 © 鑄輥與金屬製無接縫皮帶間挾壓時，挾壓力太高的情況下 發生。爲了防止儲存所（bank )的發生，挾壓力爲 20N/mm以下較理想，更理想爲ΙΟΝ/mm以下。而且，由 T模頭擠出之熔融狀薄片使用澆鑄輥與空氣腔而冷卻之方 法、熔融狀薄片使用澆鑄輥與靜電釘扎之冷卻方法，因沒 有在輥間挾壓熔融狀薄片，不會發生儲存所（bank)，因 此，因面內相位差的減少而有利。 而且，以前述的方法所得之本發明的光學薄膜，使用 作爲偏光子保護薄膜、相位差用原料薄膜的情況下，構成 -14- 201012834 本發明的薄膜之丙烯系共聚物具有含蝶形（smectic )晶 之結晶’該丙烯系共聚物之全部結晶中佔有蝶形晶的比例 爲90%以上較理想。該丙烯系共聚物的主要結晶構造有 α晶與蝶形晶，前述偏光子保護薄膜、相位差用原料薄膜 ’其丙烯系共聚物之全部結晶中佔有蝶形晶的比例爲90 %以上較理想。於本發明，所謂全部結晶佔有蝶形晶的比 例’係指以廣角X射線繞射測定之X射線繞射輪廓之全 Φ 部面積中’來自蝶形晶之輪廓面積的比例。繞射輪廓中大 部分爲來自蝶形晶之輪廓較理想。而且，即使存在α晶的 情況下’該α晶不是球晶構造較理想。 所謂來自α晶之繞射輪廓，係指繞射角（20)爲10 〜30度的範圍之廣角X射線繞射測定下觀察的14.2度附 近、16.7度附近、18.5度附近及21.4度附近之4個尖峰 所成者，所謂來自蝶形晶之繞射輪廓，係指1 4.6度附近 、21.2度附近之2個寬峰所成者。 ® 繞射輪廓中大部分是否係來自蝶形晶之輪廓，可由繞 射角爲13〜15度範圍所示的峰是否寬闊而判定，該峰爲 寬闊時，繞射輪廓中大部分係來自蝶形晶之輪廓。具體地 ，如以下判定。於X射線繞射輪廓，在繞射角爲13〜15 度範圍，繞射強度最高之峰的強度爲C時，該峰的CxO.8 程度之峰寬度D爲1度以上的情況，判定繞射輪廓中大 部分係來自蝶形晶之輪廓。（參照圖1) 廣角X射線繞射輪廓的全部面積中佔有來自蝶形晶 之輪廓面積的比例係由下述式算出。 -15- 201012834 (1) 繞射輪廓的大部分是否係來自蝶形晶之輪廓， 以上述方法判定。 (2) 判定繞射輪廓的大部分係來自蝶形晶之輪廓時 ’由以下的順序算出來自蝶形晶之輪廓面積的比例。 (3) 繞射輪廓以峰分離軟體處理，使蝶形晶之輪廓 與晶之輪廓分離。 (4) 於繞射角爲1〇〜30度範圍，求出繞射輪廓的全 0 部面積與來自蝶形晶之繞射輪廓的面積，算出相對前者之 後者的比例。 全部結晶中佔有蝶形晶之比例爲9 0 %以上之本發明 的薄膜，係使用丙烯系共聚物，例如冷卻輥的表面溫度爲 2(TC以下而可製作。例如，於由Τ模頭擠出之熔融狀薄片 在2個輥間挾壓的方法之情況，只要至少一個輥的表面溫 度爲20°C以下。而且，減少全部結晶中佔有α晶的比例上 有利的點，以藉由澆鑄輥與接觸輥之挾壓的方法、澆鑄輥 ❹ 與使該澆鑄輥沿其圓周方向壓接而設置之金屬製無接縫皮 帶間挾壓之方法較理想。而且，熔融體冷卻固化時，爲使 熔融體全體可快速冷卻，薄膜的厚度爲30〜200 yin較理 想。 爲了得到光學的均勻性更佳之相位差薄膜，於延伸所 供應的原料薄膜之厚度不均勻小較理想。原料薄膜之厚度 的最大値與最小値之差爲l〇"m以下較理想，更理想爲4 y m以下。 藉由延伸原料薄膜，可得相位差薄膜。作爲原料薄膜 -16- 201012834 的延伸方法，例如縱延伸、橫延伸、逐次二軸延伸、同時 二軸延伸。相位差薄膜係根據組裝的液晶顯示裝置之種類 ，而製作該相位差薄膜之延伸方法有不同’有只進行縱延 伸的情況、有只進行橫延伸的情況，也有二軸延伸的情況 。使用於垂直配向模式液晶顯示器的情況下’藉由二軸延 伸製作相位差薄膜。於逐次二軸延伸的情況，以先進行縱 延伸後進行橫延伸的方法與先進行橫延伸後進行縱延伸的 _ 方法中的任一種方法進行皆可。 作爲縱延伸的方法，例如藉由2個以上輥之旋轉速度 差而延伸原料薄膜之方法、長跨距延伸法。所謂長跨距延 伸法，係指使用2對壓送輥（nip roll)與其間具有烤箱 之縱延伸機，在該烤箱中，一邊加熱原料薄膜一邊藉由前 述2對壓送輥的旋轉速度差而延伸之方法。爲了得到光學 的均勻性更佳之相位差薄膜，以長跨距延伸法較理想。特 別是使用氣流方式的烤箱較理想。所謂氣流方式的烤箱， 〇 係指該烤箱中導入原料薄膜時，於該原料薄膜的兩面，從 上部噴嘴與下部噴嘴可吹出熱風之構造。複數的上部噴嘴 與下部噴嘴係於薄膜的流動方向交互設置。該烤箱中，一 邊使原料薄膜不接觸上部噴嘴與下部噴嘴的任一者，一邊 進行延伸。於該情況的延伸溫度（亦即烤箱中的環境溫度 )，在所使用的丙烯系共聚物的熔點低9(TC之溫度（Tm_ 90°C )以上’所使用的丙烯系共聚物的熔點以下較理想。 於烤箱分爲2區的情況，各區的溫度可設定成相同，可爲 相異。縱延伸倍率無特別限制，通常爲i.Oi〜5倍，爲了 -17- 201012834 得到光學的均勻性更佳之相位差薄膜’以1.05〜3倍較理 想。 作爲橫延伸的方法，例如以夾頭等固定兩端之原料薄 膜，在烤箱中擴大夾頭的間隔而延伸之拉幅法。橫延伸倍 率，通常爲2〜10倍，從所得之相位差薄膜的光學的均勻 性高之觀點，4〜7倍較理想。特別是依序經下述步驟進 行橫延伸更理想。 φ 將原料薄膜或縱延伸的薄膜，以前述薄膜所使用的丙 烯系共聚物的（Tm-30°C )以上、（Tm+10°C )以下的預 熱溫度進行預熱步驟； 將預熱的前述薄膜，以比前述預熱溫度低的延伸溫度 ，於橫方向進行延伸的步驟； 將橫方向延伸的前述薄膜進行熱固定的步驟。 以拉幅法進行橫延伸的情況下，使用進行預熱步驟的 區、進行延伸步驟的區、進行熱固定步驟的區之烤箱溫度 ❹ 可獨立溫度調節之裝置。藉由前述條件下進行橫延伸，可 得軸精度佳且具有均勻的相位差之相位差薄膜。 橫延伸的預熱步驟，係薄膜在寬度方向延伸步驟前所 設置的步驟，爲了延伸薄膜，加熱該薄膜至充分高的溫度 之步驟。此處，預熱步驟的預熱溫度，係指烤箱的進行預 熱步驟的區內的環境溫度，含於延伸薄膜之丙烯系共聚物 的熔點以上之溫度。預熱溫度對所得的相位差薄膜之軸精 度有大的影響，於比熔點低的預熱溫度，所得的相位差薄 膜，無法達成均勻的相位差。延伸的薄膜之預熱步驟滯留 -18- 201012834 時間爲30〜120秒較理想。在該預熱步驟之滯留時間未達 30秒的情況，在延伸步驟使薄膜延伸時，應力分散，作 爲相位差薄膜的軸、相位差的均勻性可能受到不利的影響 ，而且，於滯留時間超過1 20秒的情況，受到需要以上的 熱，薄膜部分溶解，可能下引（向下垂）。預熱步驟之滯 留時間爲3 0〜60秒更理想。 橫延伸之延伸步驟，係將薄膜於寬度方向延伸的步驟 φ 。在該延伸步驟的延伸溫度（此係指烤箱的進行延伸步驟 的區內的環境溫度）係比預熱溫度低的溫度。已預熱的薄 膜，藉由比預熱步驟低的溫度進行延伸，該薄膜可均勻地 延伸，結果，可得光軸及相位差均勻性佳之相位差薄膜》 延伸溫度係比預熱步驟之預熱溫度低3〜20 °C較理想，低 5〜1 5 °C更理想。 所謂橫延伸的熱固定步驟，係指延伸步驟結束時在保 持薄膜寬度的狀態下使該薄膜通過烤箱內的既定溫度的環 φ 境內之步驟。爲了有效地提高薄膜的相位差、光軸等光學 特性的安定性，熱固定溫度，在比延伸步驟之延伸溫度低 20°C的溫度至比延伸步驟之延伸溫度高30°C的溫度之範圍 內較理想。 橫延伸的步驟，進而可具有熱緩和步驟。該步驟，於 拉幅法中，設置於延伸區與熱固定區之間，從其他區獨立 ，在可溫度設定之熱緩和區進行。具體地，熱緩和係於延 伸步驟延伸薄膜至既定的寬度後’使夾頭間隔只縮減數％ (通常0.1〜10%) ’除去無益的歪斜而進行。 201012834 延伸係在原料薄膜的蝶形晶的比例爲90%以上的狀 態下進行，因可使相位差的均勻性高的相位差薄膜生成， 所以較理想。即使原料薄膜剛製造後蝶形晶的比例爲90 %以上，隨時間的經過蝶形晶的比例下降，有蝶形晶的比 例變成未達90%的情形。因此，製造原料薄膜後，168小 時內進行延伸較理想，72小時內進行延伸更理想。而且 ，製造的原料薄膜不捲取、依原樣進行延伸之方法，因蝶 φ 形晶的比例高的狀態下進行延伸，所以較理想。爲了保持 原料薄膜之蝶形晶的比例爲90%以上的狀態，製造原料 薄膜後至延伸之間，儘可能將原料薄膜保管於低溫較理想 。原料薄膜的保管溫度，具體地30°C以下較理想，20°C以 下更理想，l〇°C以下特別理想。原料薄膜的保管溫度之下 限無特別限制，保管溫度通常在-10°c以上。 相位差薄膜所要求的相位差，隨該相位差薄膜組裝的 液晶顯示裝置的種類而異，通常面內相位差R〇爲30〜 φ 300nm。使用於後述的垂直配向模式液晶顯示器的情況下 ，從視角特性佳的觀點，面內相位差R〇爲40〜70nm，厚 度方向相位差Rth爲90〜23 Onm較理想。藉由控制相位差 薄膜製造時的延伸倍率與所製造之相位差薄膜的厚度，可 得具有所期望的相位差之相位差薄膜。 本發明的相位差薄膜，其薄膜面內（500mm寬度 x500mm長度面內）之相位差的最大値與最小値之差爲 10nm以下，於測定薄膜的寬度方向5 0 0mm之光軸的情況 ，光軸爲-1°以上+1°以下，係光學均勻性高的相位差薄膜 -20- 201012834 本發明的光學薄膜之厚度無特別限制，依據所設計的 相位差値等適當設定，通常爲5〜500以〇1，較理想爲1〇 〜100"m，更理想爲10〜60/zm。 本發明的光學薄膜之內部霧度爲1.0 %以下較理想， 更理想爲0.5%以下。內部霧度小，非常透明時，使用本 發明的光學薄膜之液晶顯示裝置的正面對比變高。霧度係 φ 表示薄膜的透明性之指標，霧度越小，薄膜越透明。霧度 係根據Jis K-7 136可測定之物性値。薄膜的透明性係受 到起因於薄膜的表面狀態的散射影響以及起因於結晶狀態 等薄膜的內部狀態之散射影響，各散射的程度越大，薄膜 的透明性越低。起因於薄膜的表面狀態的散射影響而降低 的透明性，因使用本發明的光學薄膜之液晶顯示裝置的正 面對比不會降低，爲了正確地評價本發明的光學薄膜的性 能，以除去起因於薄膜的表面狀態的散射影響而降低的透 φ 明性之値，進行評價。該指標於本發明稱爲內部霧度。內 部霧度，係將薄膜於石英玻璃製的容器（cell )，在放入 具有幾乎與聚丙烯系樹脂相同的折射率之液體的酞酸二甲 酯與測定的薄膜的狀態下，以根據JIS K-7136的方法測 定的値。 本發明的光學薄膜，可爲只由丙烯系共聚物爲主成份 的層所成的單層薄膜，可爲含有前述層之多層薄膜》於多 層薄膜的情況，可藉由共擠出法製造，也可以由相異的薄 膜彼此貼合。而且，單層或多層薄膜，可藉由塗佈層合層 -21 - 201012834 本發明的光學薄膜’可使用於液晶顯示器等的平面面 板顯示器、偏光板保護膜、相位差薄膜、視角擴大薄膜及 亮度提高薄膜等。其中，適合於相位差薄膜。 本發明的光學薄膜，可使用作爲液晶顯示裝置的一部 份，例如貼附於液晶胞的單側或兩側的方法、不介由黏著 層而層合於液晶胞的方法。而且，於本發明的光學薄膜， 也可塗佈硬塗層、防眩層、抗反射層、保護層、黏著層、 配向膜、液晶層。 本發明的相位差薄膜，與各種偏光板、液晶層等層合 ，使用作爲手機、個人數位助理（PDA )、個人電腦、大 型電視等的液晶顯示裝置較理想。作爲層合本發明的相位 差薄膜使用的液晶顯示裝置（LCD )，例如光學補償彎曲 (OCB)式、垂直配向（VA)式、橫電場（IPS)式、薄 膜電晶體（TFT )式、扭曲向列（TN )式、超扭曲向列（ STN )式等各種模式的液晶顯示裝置。特別是使用於VA 式的液晶顯示裝置的情況，有改善視角依賴性的效果。液 晶顯示裝置，一般係於具有2片基板及夾於其間的液晶層 之液晶胞的兩側，分別配置偏光板，從配置於其一者的外 側（背面側）之背光的光中，只有平行液晶胞與背光之間 的偏光板的透過軸之直線偏光，會向液晶胞入射。背面側 偏光板與液晶胞之間及/或表面側偏光板與液晶胞之間介 由黏著層而配置。而且，偏光板通常係由保護聚乙烯醇所 成的偏光薄膜用2片三乙醯基纖維素（TAC )薄膜等保護 -22- 201012834 薄膜介由黏著劑夾持所構成，本發明的相位差薄膜，係取 代表面側偏光板及/或背面側偏光板的液晶胞側之保護薄 膜’將其以黏著劑與偏光薄膜貼合，可達到光學補償薄膜 (相位差薄膜）與保護薄膜兩者的作用。 [實施例] 以下’藉由實施例，更具體地說明本發明。 Φ 物性測定係如下述進行。 (ο結晶熔解熱量及結晶化熱量及熔點 根據JIS K 7122，藉由差示掃描熱量計（精工電子工 業（股）公司製DSC220C:輸入補償DSC)進行測定。 具體地，作爲狀態調整，將樣品聚合物以30 T：/分從室溫 升溫至200°C爲止’於20CTC保持5分鐘。然後，以i(TC/ 分降溫至-50 °C爲止（步驟1)，於-501保持5分鐘後， ❹ 以10 °C/分從-50 °C升溫至200 °C爲止（步驟2)，進行熱量 測定。由步驟1的DSC曲線的結晶化峰求得結晶化熱量 ’由步驟2的DSC曲線的結晶熔解峰求得結晶熔解熱量 。而且，該熔解峰的頂點之溫度爲熔點（Tm)。 (2)丙烯系共聚物中來自1-丁烯的單體單位的含量（莫 耳％ ) 來自1-丁烯的單體單位的含量係由IR光譜的測定進 行’根據「高分子手冊」（1995年、紀伊國屋書店發行 -23- 201012834 )的第619頁記載的方法求得。 (3) 丙烯系共聚物中來自乙烯的單體單位的含量（莫耳 % ) 來自乙烯的單體單位的含量係進行IR光譜的測定， 根據「高分子手冊」（1 995年、紀伊國屋書店發行）的 第616頁記載的有關（i)無規共聚物之方法求得。 β (4) 熔融指數（MFR) 根據JIS Κ7210，於溫度230°C，負載21.18Ν下測定 (5)丙烯系共聚物的結晶晶格常數 將丙烯系共聚物，使用神藤金屬工業製壓縮成形機 AYSR-10型，於23 0°C下5分鐘預熱後，以5分鐘升壓至 5.0MPa，保壓5分鐘。然後，於30°C冷卻5分鐘，製成 厚度1 mm的樣品，廣角X射線繞射以下述條件進行測定 〇 機種 理學（Rigaku)製 RINT2000 管球 Cu[Technical Field] The present invention relates to an optical film excellent in optical homogeneity which can be produced at low cost. [Prior Art] A liquid crystal display device used in a mobile phone, a liquid crystal television or the like uses an optical film such as a retardation film in order to compensate for the optical distortion caused by the optical anisotropy of the liquid crystal and the visual color depending on the visual direction. As the material of the optical film, a synthetic resin such as a polycarbonate resin or a cyclic olefin polymer is used, but the price of such a synthetic resin is high. An optical film formed of a low-cost resin is known as a phase difference plate made of a film made of a propylene-ethylene copolymer, as described in JP-A-60-24502. However, the film of the propylene-ethylene φ copolymer described in JP-A-60-24502 has a large difference in phase difference and has a problem of poor optical homogeneity, and further improvement is required. SUMMARY OF THE INVENTION An object of the present invention is to provide an optical film which can be produced at a low cost and which is excellent in optical homogeneity. The present invention has a crystal lattice constant obtained by wide-angle X-ray diffraction measurement of a monomer unit derived from 1-butene and a propylene-based copolymer of monomer units derived from propylene. The length of the a-axis is greater than -5 - 201012834 6.70A, the layer of the propylene-based copolymer having a b-axis length greater than 21.5 A as a main component. [Embodiment] A resin used as a main component of the optical film of the present invention has a propylene-based copolymer of a monomer unit derived from 1-butene and a monomer unit derived from propylene by wide-angle X-ray diffraction. The obtained crystal lattice constant has an a-axis length of more than 6.7 A and a b-axis length of more than 21.5 A. A film in which a propylene-based copolymer having a crystal lattice constant satisfying the above conditions is a main component is excellent in optical homogeneity. The crystal lattice constant of the propylene-based copolymer can be determined by a wide-angle X-ray diffraction measurement using a laminated film of a propylene-based copolymer. Specifically, the following method is used. (1) The production width of the film is 100 mm×100 mm×1 mm in a metal frame, and 9 to 9.5 g of a propylene-based copolymer is placed, and 23 (after preheating for 5 minutes at TC, the pressure is raised from normal pressure to 5 in 5 minutes. OMP a, holding pressure for 5 minutes, and then cooling at 3 ° C for 5 minutes to prepare a sample having a thickness of 1 mm. (2) Wide-angle X-ray diffraction measurement of the sample obtained by the method of the above (1), The condition is measured by wide-angle X-ray diffraction. Rigaku RINT2000 201012834 Ball Cu voltage 50KV Current 100 div Divergence slit 1.0. Scatter slit 1.0. Receiving slit 0.15 Measurement range 2 Θ : 5 to 3 5 ° (3) In the wide-angle X-ray diffraction spectrum obtained by calculation of the crystal lattice constant, the diffraction peak intensity is in a region where the diffraction angle 20 is 丨6. 〇17.0°. The diffraction angle of the maximum 値 is 20 (. 4 〇), and in the region where the diffraction angle 20 is 12.5~15.〇, the diffraction peak intensity shows a maximum 绕 diffraction angle of 20 (11()). 0(.4()) and θ(ΐΐβ) are substituted into 0 of the following formula d = i^/2Sin0 (η=1, λ=1.54Α), and each crystal lattice plane is obtained. The φ axis and the a-axis length of the crystal lattice constant are obtained by the following equation: b-axis length = 4d (〇4〇) a-axis length = b-axis length xd (11G) / (b-axis length 2_d 2 1/2 • ^ ( 1 1 0)) The crystal lattice constant of the propylene copolymer is controlled mainly by the copolymerization ratio of 1-butene copolymerized with propylene. Usually it is derived from the propylene-based copolymer. - the amount of the monomer unit of butene is increased, and the length of the a-axis length is also increased. The propylene-based copolymer of the present invention is a propylene-based copolymer having a monomer unit derived from h-butene and propylene 201012834. The propylene-based copolymer having a crystal lattice constant of greater than 6 7 〇a and a b-axis length greater than 21.5 A as determined by X-ray diffraction measurement, for example, from 70 to 97.5 mol% of monomer units derived from propylene a propylene _ 1-butylene random copolymer with 2.5 to 30 mole % of monomer units derived from oxime - butene (but the propylene-1-butene random copolymer contains propylene) The sum of the monomer unit and the monomer unit derived from 1-butene is 0 100 mol %). The monomer sheet derived from 丨_butene in the propylene-1-butene random copolymer The content 'from the viewpoint of the optical use of the resulting copolymer homogeneity, more ideal than 2.5 mole%, more preferably less than 1〇 mole%, more ideally less than 18 mole%. Further, in the case where the content of bismuth-butene is large, adhesion of particles is likely to occur. From the viewpoint of handling, it is preferably 3 〇 mol% or less, more preferably 25 mol% or less, and even more preferably 22 mol. Less than the ear. The propylene-based copolymer of the present invention may contain a monomer unit derived from a monomer other than propylene and 1-butyl. Examples of such a monomer include ethylene, an olefin having 5 to 10 carbon atoms, a polyolefin compound, a cyclic olefin, and an ethylenic aromatic compound. As the above-mentioned olefin, such as 1-pentene, 1-hexene, 1-heptene, 1-octene, decene, decene, etc., linear α olefin, 3-methyl-1-butene, 3-methyl A group of α-olefins such as quinone-pentene, 4-methyl-p-pentene, 2-ethyl-1-hexene, 2,2,4-dimethyl-1-indene. The content of the monomer unit derived from the monomer other than propylene and butene of the propylene-based copolymer is usually 20 mol% or less, preferably 1 mol% or less -8 - 201012834, the propylene-based copolymer of the present invention, According to the differential scanning calorimetry of ns Κ 7122, the melting heat of the crystal observed at -50 to 200 ° C is a crystal melting peak of IJ/g or more, or a crystallization peak having a crystallization heat of 1 J/g or more. The polymer is preferably a copolymer of a two-peak peak having a crystal dissolution peak of 30 J/g or more and a crystallization peak of 30 J/g or more. In the case of exhibiting such a thermally reacted copolymer, even when it is used under conditions of φ for a long period of time, such as a liquid crystal television, it becomes a film which is hard to shrink and whose optical quality is not easily lowered. The stereoregularity of the propylene-based copolymer used as the main component of the optical film of the present invention is preferably a polymer having an isotactic structure or a syndiotactic structure. The MFR of the propylene-based copolymer used in the present invention is preferably from 0.1 to 20 g/10 minutes, more preferably from 2 to 20, from the viewpoint of workability. Further, MFR is measured according to JIS K7210 at a temperature of 230 ° C and a load of 21.18 N @. The propylene-based copolymer used in the main component of the optical film of the present invention, for example, a Ziegler-Natta type catalyst, a catalyst containing a transition metal compound of Groups 4 to 6 of the periodic table. Or a metallocene catalyst, which is produced by copolymerizing propylene with 1-butene and a monomer which is additionally used as needed. As a Ziegler-Natta type catalyst, for example, a solid transition metal component containing titanium and a catalyst containing an organic metal component, etc., as a metallocene catalyst, for example, at least one The cyclopentadiene form is separated from the catalyst of the transition metal compound of Group 4 to Group 6 of the periodic table of 201012834 sub-framework. As the polymerization method, for example, a slurry polymerization method, a gas phase polymerization method, a monolith polymerization method, a solution polymerization method, or the like. These polymerization methods can be applied to a one-stage polymerization method using a single-stage polymerization method or a combination of these polymerization methods. The optical film 'of the present invention' contains at least one layer of the above-mentioned propylene-based copolymer as a main component. Here, the content of the layer-based propylene-based copolymer containing the propylene-based copolymer as a main component is more than 50% by weight, more preferably 70% by weight or more, more preferably 90% by weight or more, and more preferably 95% by weight or more. The weight % is ideal. In the optical film of the present invention, the layer of the propylene-based copolymer as a main component may contain a polyolefin-based resin or a modified polyolefin-based copolymer other than the propylene-based copolymer, as long as the effect of the present invention is not impaired. Other resins such as a resin, a rosin-based resin, a terpene-based resin, a synthetic petroleum resin, a coumarone-based resin, a phenol-based resin, and a xylene-based φ lipid 'isoprene-based resin. The polyolefin-based resin other than the propylene-based copolymer is, for example, a copolymer of propylene alone, a copolymer of propylene and ethylene, and one or more kinds of olefins selected from the group consisting of α-olefins having 5 to 20 carbon atoms, and ethylene alone. A copolymer of an olefin, a mixture of ethylene and a carbon number of 3 to 20, or the like. As the modified polyolefin-based resin, for example, maleic anhydride, dimethyl phthalate, diethyl maleate, acrylic acid, methacrylic acid '23 ft citric acid, glycidyl methacrylate A polyolefin-based resin modified with a modifier such as hydroxyethyl methacrylate. Here, the poly-201012834 olefin-based resin used for the modification may be a conventional polyolefin such as a vinyl resin, a uniform polypropylene, a syndiotactic polypropylene, a comon-containing random polypropylene, or the like. Multi-stage polymerization of block type polypropylene, poly(4-methyl-pentene), poly(1-butene), and the like. As rosin-based resins, for example, natural rosin, polymerized rosin, partially nitrided rosin, fully hydrogenated rosin, esterified rosin (such as glyceride, pentaerythritol, ethylene glycol ester, methyl ester), rosin derivative (for example) Not φ homogenized rosin, citric acid rosin, calcified rosin). As a polydecene-based resin, for example, a single polymer of a cyclic terpene such as α-weirene, $-indene green, or di-pentene, a copolymer of a cyclic terpene, a cyclic ketene, a phenol such as a phenol, or a bisphenol Copolymer of a compound (for example, a terpene-bisphenol resin such as α-pinene-phenol resin, dipentene-phenol resin, terpene-bisphenol resin), copolymerization of a cyclic terpene and an aromatic monomer Aromatic modified terpene resin. As a synthetic petroleum resin, for example, a c5 fraction of a naphtha decomposition oil, a Φ (^~(:: a separate polymer of a fraction and other olefinic fractions, a copolymer, a hydride of the individual polymer, a hydride of the copolymer) a petroleum resin, an aromatic petroleum resin, an alicyclic petroleum resin, or an aliphatic alicyclic copolymer. As a synthetic petroleum resin, for example, a copolymer of the above naphtha decomposition oil and the above terpene, the copolymer Hydride copolymerization petroleum resin. Preferred C5 fraction for naphtha decomposition oil, such as isoprene, cyclopentadiene, 1,3-pentadiene, 2-methyl-butene, a methyl butylene such as 2-methyl-2-butene, a pentene such as a pentene or a 2-pentene, or a dicyclopentadiene. -11 - 201012834 As a c6-Cu fraction, it is preferably 茚 ( Indene), styrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, Ct-methylstyrene, methylstyrene, etc., methyl styrene, methyl hydrazine, ethyl hydrazine, Vinyl xylene, propylene benzene. As other olefinic fractions, it is preferably butene, hexene, Alkenes, octenes, butadienes, octadienes, as coumarone-based resins, for example, a single polymer of coumarone or a copolymer of coumarone and hydrazine, etc. φ as a phenolic resin, such as an alkylphenol resin An alkylphenol-acetylene resin which is condensed with an alkylphenol and acetylene, and a modified product of such a resin. Here, as such a phenolic resin, a phenol which is hydroxymethylated with an acid catalyst may be used. Any one of a resin type resin and a cresol type resin which is methylolated with an alkali catalyst; a xylene type resin, for example, a xylene-formaldehyde resin formed of m-xylene and formaldehyde, and the third A modified resin obtained by reacting a component. As an isoprene-based resin, for example, a resin obtained by copolymerizing a C10 φ alicyclic compound of a dimer of isoprene and a C1 () chain compound. When it is mixed with another resin, it is preferable to use a resin which does not change the crystal lattice constant of the propylene-based copolymer when it is kneaded with the above-mentioned propylene-based copolymer. That is, the phase is soluble in the amorphous portion of the propylene-based copolymer. The resin is preferred. The optical film of the present invention An additive such as an antioxidant, a nucleating agent, a lubricant, or a charge prevention agent may be added in the range of the effect of the invention. Examples of the method for producing an optical film of the present invention include a solvent casting method and an extrusion molding method. In the method, a thermoplastic resin is dissolved in a solution of an organic -12-201012834 solvent, and is cast on a substrate having a release-type biaxially stretched polyester film or the like by a die coating method, followed by drying to remove an organic solvent. A method of forming a film on a substrate, and a film formed on the substrate in such a manner is used after being peeled off from the substrate, and as an extrusion molding method, for example, a blow molding method, a T die method, a calendering method, or the like. From the viewpoint of manufacturing cost, the extrusion molding method is preferable, and the T-die method is preferable from the viewpoint of optical homogeneity. The optical film of the present invention can be produced by T-die extrusion molding as φ from the T die. a method of cooling and solidifying an extruded melt, for example, a method of cooling using a casting roll and an air chamber, a method of rolling by a casting roll and a contact roll, a casting roll, and a casting roll along the circle thereof Crimping direction is provided between the metal seamless belt system nip-pressing method, the cooling method using a casting roll and the electrostatic bar as nails. In the case of using a casting roll for cooling, in order to obtain a phase difference film having better transparency, the surface temperature of the casting roll to be used is preferably -10 to 30 °C. In the case of producing a film by a rolling method of a casting roll and a contact roll, as a contact roll, an outer cylinder formed by a rubber roller or a seamless belt made of elastically deformable metal and the inside of the outer cylinder are A roller made of an elastically deformable elastic body and having a structure in which the outer cylinder and the elastic roller are filled with a medium for temperature adjustment is preferable because a film having a small alignment and excellent optical homogeneity can be obtained. In the case where a rubber roller is used as the contact roller, in order to obtain a mirror-shaped optical film, the melt extruded from the T die is preferably pressed together with the support between the casting roller and the rubber roller. As the support, a biaxially stretched film made of a thermoplastic resin having a thickness of 5 to 50 /z m is preferable. -13- 201012834 In the case of forming a film by a method of rolling between a casting roll and a metal seamless belt which is provided by crimping the casting roll in the circumferential direction thereof, the aforementioned seamless belt is in the circumferential direction of the casting roll In the above, the plurality of rolls arranged by being parallel to the casting rolls are preferably kept. More preferably, the seamless belt is held by two rolls having a diameter of 100 to 30 mm, and the thickness of the seamless belt is 100 to 500 jum. The optical film of the present invention obtained by the above method is suitable for, for example, a polarizer protective film because of its excellent alignment φ and excellent optical homogeneity. Moreover, such a film can be suitably used as a phase difference film by extending in at least one direction. Hereinafter, the pre-stretch film used in the production of the retardation film is referred to as a raw material film. As the raw material film, a film having an in-plane retardation of 50 nm or less is preferably used. In order to reduce the in-plane phase difference of the obtained film to 5 Onm or less, it is necessary to prevent the formation of a bank (resin accumulation) in the step of cooling and solidifying the molten sheet extruded from the T die. A bank refers to a situation in which a molten sheet is pressed between a casting roll and a contact roll, and between a casting roll and a metal seamless belt, when the pressure is too high. In order to prevent the occurrence of a bank, the crucible pressure is preferably 20 N/mm or less, more preferably ΙΟΝ/mm or less. Further, the molten sheet extruded from the T die is cooled by a casting roll and an air chamber, and the molten sheet is cooled by a casting roll and electrostatic pinning, since the molten sheet is not pressed between the rolls, and A bank is generated, and therefore, it is advantageous because the in-plane phase difference is reduced. Further, in the case where the optical film of the present invention obtained by the above method is used as a polarizing film and a film for phase difference, the propylene-based copolymer constituting the film of the present invention has a butterfly-like shape (smectic). Crystalline crystals The ratio of the butterfly crystals in the entire crystal of the propylene-based copolymer is preferably 90% or more. The main crystal structure of the propylene-based copolymer is α-crystal and butterfly crystal, and the ratio of the butterfly crystal in the entire crystal of the acryl-based copolymer of the polarizer protective film and the phase difference raw material film is preferably 90% or more. . In the present invention, the ratio "the total crystal occupies the butterfly crystal" refers to the ratio of the area of the contour of the butterfly crystal from the total Φ area of the X-ray diffraction profile measured by the wide-angle X-ray diffraction. Most of the diffraction profile is ideal from the shape of a butterfly crystal. Moreover, even in the case where α crystal is present, the α crystal is not a spherulite structure. The diffraction profile from the α crystal refers to the vicinity of 14.2 degrees, 16.7 degrees, 18.5 degrees, and 21.4 degrees observed under wide-angle X-ray diffraction measurement in a range of 10 to 30 degrees of diffraction angle (20). The four peaks, the diffraction profile from the butterfly crystal, are the two broad peaks near 1 4.6 degrees and 21.2 degrees. ® Whether most of the diffraction profile is from the shape of a butterfly crystal, can be judged by whether the peak indicated by the diffraction angle is in the range of 13 to 15 degrees is wide. When the peak is broad, most of the diffraction profile is from the butterfly. The shape of the crystal. Specifically, it is determined as follows. In the X-ray diffraction profile, when the diffraction angle is in the range of 13 to 15 degrees and the intensity of the peak with the highest diffraction intensity is C, the peak width D of the CxO.8 degree of the peak is 1 degree or more. Most of the contours are from the contours of the butterfly crystal. (Refer to Fig. 1) The ratio of the area of the contour of the butterfly crystal from the entire area of the wide-angle X-ray diffraction profile is calculated by the following equation. -15- 201012834 (1) Whether most of the diffraction profile is derived from the contour of the butterfly crystal is determined by the above method. (2) When it is determined that most of the diffraction profile is derived from the contour of the butterfly crystal, the ratio of the contour area from the butterfly crystal is calculated by the following procedure. (3) The diffraction profile is processed by the peak separation software to separate the contour of the butterfly crystal from the contour of the crystal. (4) The area of the entire zero area of the diffraction profile and the area of the diffraction profile from the butterfly crystal are obtained in the range of the diffraction angle of 1 〇 to 30 degrees, and the ratio of the latter to the latter is calculated. The film of the present invention in which the proportion of the butterfly crystals in all the crystals is 90% or more is a propylene-based copolymer, and for example, the surface temperature of the cooling roll is 2 (TC or less). For example, it is extruded by a die. In the case of the method of rolling the molten flakes between two rolls, the surface temperature of at least one of the rolls is 20 ° C or less. Moreover, it is advantageous to reduce the proportion of the α crystals in all the crystals by casting. The method of rolling the roll and the contact roll, the method of casting the roll ❹ and the metal seamless belt which is provided by crimping the casting roll in the circumferential direction thereof are preferable, and when the melt is cooled and solidified, The entire melt can be rapidly cooled, and the thickness of the film is preferably 30 to 200 yin. In order to obtain a phase difference film having better optical uniformity, the thickness of the raw material film to be stretched is less than ideal. The difference between the maximum 値 and the minimum 为 is preferably less than or equal to m, and more preferably less than 4 ym. By extending the raw material film, a retardation film can be obtained. As a raw material film-16-201012834 The method includes, for example, longitudinal stretching, lateral stretching, sequential biaxial stretching, and simultaneous biaxial stretching. The retardation film is different according to the type of the liquid crystal display device to be assembled, and the method for forming the retardation film is different. In the case where there is only a lateral extension, there is also a case where the two-axis extension is used. When used in a vertical alignment mode liquid crystal display, a retardation film is formed by biaxial stretching. In the case of successive two-axis stretching, the longitudinal direction is performed first. The method of performing the lateral stretching after the stretching may be carried out by any one of the methods of performing the longitudinal stretching and then the longitudinal stretching. As a method of the longitudinal stretching, for example, the raw material film is extended by the difference in the rotational speed of the two or more rolls. Method, long span extension method. The so-called long span extension method refers to the use of two pairs of nip rolls and a longitudinal stretching machine with an oven therebetween, in which the raw material film is heated while the above 2 A method of extending the rotational speed difference of the nip rolls. In order to obtain a phase difference film having better optical uniformity, the long span stretching method is preferable. In particular, an air-flow type oven is preferred. The air-flow type oven refers to a structure in which hot air can be blown from the upper nozzle and the lower nozzle on both sides of the raw material film when the raw material film is introduced into the oven. The nozzle and the lower nozzle are alternately arranged in the flow direction of the film. In the oven, the raw material film is extended without contacting either the upper nozzle and the lower nozzle. The extension temperature in this case (that is, the environment in the oven) The temperature of the propylene-based copolymer to be used is preferably 9 or less (the temperature of TC (Tm_90° C.) or more and less than the melting point of the propylene-based copolymer used). The temperature of the zone can be set to be the same and can be different. The longitudinal stretch ratio is not particularly limited, and is usually i.Oi~5 times. For the -17-201012834, the optical uniformity is better. The phase difference film is 1.05~3 times. More ideal. As a method of lateral stretching, for example, a tenter method in which a raw material film at both ends is fixed by a chuck or the like, and the interval between the chucks is widened in the oven is extended. The lateral stretching ratio is usually 2 to 10 times, and 4 to 7 times is preferable from the viewpoint of high optical uniformity of the obtained retardation film. In particular, it is more desirable to carry out the lateral stretching in the following steps. φ preheating the raw material film or the longitudinally stretched film with a preheating temperature of (Tm-30 ° C) or more and (Tm + 10 ° C) or less of the propylene-based copolymer used for the film; The film is a step of extending in a lateral direction at an extension temperature lower than the preheating temperature; and a step of thermally fixing the film extending in the lateral direction. In the case of lateral stretching by the tenter method, the zone where the preheating step is performed, the zone where the stretching step is performed, the oven temperature of the zone where the heat setting step is performed, and the device capable of independent temperature adjustment are used. By performing lateral stretching under the above conditions, a retardation film having excellent axial accuracy and a uniform phase difference can be obtained. The laterally extending preheating step is a step of the film which is provided before the step of extending in the width direction, and the step of heating the film to a sufficiently high temperature for stretching the film. Here, the preheating temperature of the preheating step means the ambient temperature in the zone in which the oven is subjected to the preheating step, and the temperature in the range of the melting point of the propylene-based copolymer of the stretched film. The preheating temperature has a large influence on the axial precision of the obtained retardation film, and the resulting retardation film cannot achieve a uniform phase difference at a preheating temperature lower than the melting point. The preheating step of the extended film is retained. -18- 201012834 The time is preferably 30 to 120 seconds. In the case where the residence time of the preheating step is less than 30 seconds, stress is dispersed when the film is extended in the stretching step, and the uniformity of the axis and the phase difference as the retardation film may be adversely affected, and the residence time is exceeded. In the case of 1 20 seconds, the heat above is required, and the film is partially dissolved, which may be sag (downward). The residence time of the preheating step is preferably 30 to 60 seconds. The step of extending the lateral extension is a step φ of extending the film in the width direction. The extension temperature at the extending step (this refers to the ambient temperature in the region where the oven is subjected to the stretching step) is a temperature lower than the preheating temperature. The preheated film is extended by a temperature lower than the preheating step, and the film can be uniformly extended. As a result, a retardation film having an excellent optical axis and phase difference uniformity can be obtained. The extension temperature is preheated by the preheating step. The temperature is lower than 3~20 °C, and the lower 5~1 5 °C is more ideal. The horizontally extending heat-fixing step is a step of passing the film through a ring φ of a predetermined temperature in the oven while maintaining the film width at the end of the stretching step. In order to effectively improve the phase difference of the film and the stability of optical characteristics such as the optical axis, the heat setting temperature is in a range of 20 ° C lower than the extension temperature of the stretching step to a temperature 30 ° C higher than the stretching temperature of the stretching step. Ideal inside. The step of lateral extension, in turn, may have a thermal mitigation step. In the tentering method, the step is disposed between the extension zone and the heat fixing zone, and is independent from the other zones, and is carried out in a temperature-settable heat relaxation zone. Specifically, the heat relaxation is carried out by stretching the film to a predetermined width after the stretching step, and reducing the chuck interval by only a few % (usually 0.1 to 10%) to remove the undesired skew. In the case where the ratio of the butterfly crystals of the raw material film is 90% or more, the elongation of the film is preferably made possible by the formation of a retardation film having high uniformity of phase difference. Even if the ratio of the butterfly crystals after the production of the raw material film is 90% or more, the proportion of the butterfly crystals decreases with time, and the ratio of the butterfly crystals becomes less than 90%. Therefore, after the raw material film is produced, it is preferable to carry out the stretching within 168 hours, and it is more preferable to carry out the stretching within 72 hours. Further, it is preferable that the raw material film to be produced is not wound up and stretched as it is, and is stretched in a state where the ratio of the butterfly φ crystal is high. In order to maintain the ratio of the butterfly crystals of the raw material film to 90% or more, it is preferable to store the raw material film at a low temperature as much as possible between the production of the raw material film and the stretching. The storage temperature of the raw material film is preferably 30 ° C or less, more preferably 20 ° C or less, and particularly preferably 10 ° C or less. The storage temperature of the raw material film is not particularly limited, and the storage temperature is usually -10 ° C or more. The phase difference required for the retardation film varies depending on the type of the liquid crystal display device to which the retardation film is assembled, and the in-plane retardation R 通常 is usually 30 to φ 300 nm. In the case of the vertical alignment mode liquid crystal display to be described later, the in-plane retardation R 〇 is 40 to 70 nm from the viewpoint of excellent viewing angle characteristics, and the thickness direction retardation Rth is preferably 90 to 23 Onm. By controlling the stretching ratio at the time of production of the retardation film and the thickness of the phase difference film produced, a retardation film having a desired phase difference can be obtained. In the retardation film of the present invention, the difference between the maximum 値 and the minimum 相位 of the phase difference in the film plane (500 mm width x 500 mm length plane) is 10 nm or less, and in the case of measuring the optical axis of the film width direction of 50,000 mm, the light The axis is −1° or more and +1° or less, and is a retardation film having high optical uniformity. 20-201012834 The thickness of the optical film of the present invention is not particularly limited, and is appropriately set according to the designed phase difference ,, etc., usually 5~ 500 is 〇1, more preferably 1〇~100"m, more preferably 10~60/zm. The optical film of the present invention has an internal haze of preferably 1.0% or less, more preferably 0.5% or less. When the internal haze is small and is very transparent, the front surface contrast of the liquid crystal display device using the optical film of the present invention becomes high. The haze system φ indicates an index of transparency of the film, and the smaller the haze, the more transparent the film. Haze is a physical property measurable according to Jis K-7 136. The transparency of the film is affected by the scattering effect on the surface state of the film and the scattering effect due to the internal state of the film such as the crystalline state, and the greater the degree of scattering, the lower the transparency of the film. The transparency due to the scattering effect of the surface state of the film is lowered, and the front surface contrast of the liquid crystal display device using the optical film of the present invention is not lowered, in order to properly evaluate the performance of the optical film of the present invention, the film is removed by the film. The effect of the scattering of the surface state is reduced and the transparency is evaluated. This indicator is referred to as internal haze in the present invention. The internal haze is a film made of quartz glass in a state in which a dimethyl phthalate having a liquid having a refractive index almost the same as that of the polypropylene resin and a film to be measured are placed, in accordance with JIS. The enthalpy of the method of K-7136. The optical film of the present invention may be a single-layer film formed of a layer containing only a propylene-based copolymer as a main component, and may be a multilayer film containing the above-mentioned layer. In the case of a multilayer film, it may be produced by a co-extrusion method. It is also possible to apply a different film to each other. Further, the single-layer or multi-layer film can be applied to a flat panel display, a polarizing plate protective film, a retardation film, a viewing angle expansion film, and the like for a liquid crystal display or the like by applying the laminated layer - 21 to 201012834. Brightness enhances the film and the like. Among them, it is suitable for a retardation film. The optical film of the present invention can be used as a part of a liquid crystal display device, for example, a method of attaching to one side or both sides of a liquid crystal cell, or a method of laminating a liquid crystal cell without an adhesive layer. Further, in the optical film of the present invention, a hard coat layer, an antiglare layer, an antireflection layer, a protective layer, an adhesive layer, an alignment film, and a liquid crystal layer may be applied. The retardation film of the present invention is laminated with various polarizing plates, liquid crystal layers, etc., and is preferably used as a liquid crystal display device such as a mobile phone, a personal digital assistant (PDA), a personal computer, or a large-sized television. As a liquid crystal display device (LCD) used for laminating the retardation film of the present invention, for example, optical compensation bending (OCB) type, vertical alignment (VA) type, transverse electric field (IPS) type, thin film transistor (TFT) type, distortion Various modes of liquid crystal display devices such as a nematic (TN) type and a super twisted nematic (STN) type. In particular, when it is used in a VA type liquid crystal display device, there is an effect of improving viewing angle dependence. The liquid crystal display device is generally disposed on both sides of a liquid crystal cell having two substrates and a liquid crystal layer interposed therebetween, and is disposed with a polarizing plate, and only the light of the backlight disposed on the outer side (back side) of one of them is parallel. The linear polarization of the transmission axis of the polarizing plate between the liquid crystal cell and the backlight is incident on the liquid crystal cell. The back side polarizing plate and the liquid crystal cell and/or the surface side polarizing plate and the liquid crystal cell are disposed via an adhesive layer. Further, the polarizing plate is usually formed by protecting a polarizing film made of polyvinyl alcohol with two sheets of a triacetyl phthalocyanine (TAC) film or the like, and the film is sandwiched by an adhesive, and the phase difference of the present invention is The film is a protective film that replaces the liquid crystal cell side of the front side polarizing plate and/or the back side polarizing plate. The adhesive film is bonded to the polarizing film to achieve both an optical compensation film (phase difference film) and a protective film. effect. [Examples] Hereinafter, the present invention will be more specifically described by way of examples. Φ Physical property measurement was carried out as follows. (The crystal heat of fusion, the heat of crystallization, and the melting point are measured by a differential scanning calorimeter (DSC220C: input compensation DSC manufactured by Seiko Instruments Inc.) according to JIS K 7122. Specifically, as a state adjustment, the sample is sampled. The polymer was heated at room temperature from 30 ° C to 200 ° C for 5 minutes at 20 CTC. Then, i (TC / min was cooled to -50 ° C (step 1), and kept at -501 for 5 minutes. Thereafter, 升温 is heated from -50 °C to 200 °C at 10 °C/min (step 2), and calorimetry is performed. The crystallization peak is obtained from the crystallization peak of the DSC curve of step 1' by the DSC of step 2. The crystal melting peak of the curve is used to determine the heat of crystal melting. Moreover, the temperature at the apex of the melting peak is the melting point (Tm). (2) The content of the monomer unit derived from 1-butene in the propylene-based copolymer (% by mole) The content of the monomer unit derived from 1-butene is determined by the method described in the "Handbook of Polymers" (1995, Kiyoshiya Shoten, -23-201012834) on page 619. (3) The content of monomer units derived from ethylene in the propylene-based copolymer (% by mole) The content of the monomer unit derived from ethylene was measured by IR spectroscopy, and it was obtained by the method of (i) random copolymer described on page 616 of the "Handbook of Polymers" (published by Kiyoshiya Shoten). (4) Melt index (MFR) Measured according to JIS Κ7210 at a temperature of 230 ° C and a load of 21.18 (. (5) Crystalline lattice constant of the propylene-based copolymer, propylene-based copolymer, and a compression molding machine AYSR manufactured by Shinto Metal Industry Co., Ltd. Model -10, after preheating at 23 ° C for 5 minutes, pressurize to 5.0 MPa for 5 minutes, hold for 5 minutes, then cool at 30 ° C for 5 minutes to make a sample with a thickness of 1 mm, wide angle X Radiation diffraction was measured under the following conditions: Rigaku RINT2000 Tube Cu
電壓 50KVVoltage 50KV
電流 10 0mA 發散狹縫（divergence slit ) 1.0° 散射狹縫（scatter slit) 1.0° -24- 201012834 接收狹縫（receiving slit ) 0.15° 測定範圍 2 0 : 5〜3 5 ° 所得的廣角X射線繞射光譜中，在繞射角2 0爲16.0 〜17.0°的區域，繞射峰強度顯示極大値之繞射角爲 2 Θ (wo)、在繞射角2 0爲12.5〜15.0°的區域，繞射峰強 度顯示極大値之繞射角爲20(11Q)。將0 (040) 、 0 (110 )代入 ❿ 下式d = nX/2sin0 (η=1，λ=1.54Α)的Θ ，求得各結晶晶 格面間隔（1(040) 'duiO：)，以下述式求得結晶晶格常數之b 軸、a軸長度。 b軸長度=4d(〇4〇) a軸長度=b軸長度xd(ii〇)/( b軸長度2-d(ii〇)2)1/2 (6 )面內相位差Ro、厚度方向相位差Rth 薄膜的面內延遲相軸方向的折射率爲nx，面內前進 〇 相軸方向（在面內與延遲相軸垂直的方向）的折射率爲 ny，厚度方向的折射率爲nz，測定厚度d，面內相位差（ R〇 )及厚度方向相位差（Rth) ，分別由下式（I)及（II )定義。 R〇=(nx-ny)xd (I) Rth = [(nx + ny)/2-nz] xd (II) 各折射率係使用相位差測定裝置（王子計測機器（股 )製、KOBRA-WPR)，對藉由縱1 .5倍、橫4倍的逐次 -25- 201012834 一軸延伸法所得之薄膜，寬度300mm之相位差以16個樣 品進行測定，算出其平均。 (7 )光學的均質性 以前述（4 )測定的RQ的最大値與最小値之差，作爲 表不光學的均質性之指標。該差越小，光學的均質性越高 ，較理想。 e (8)廣角X射線繞射 原料薄膜的廣角X射線繞射係在繞射角（20)爲5〜 35度範圍進行測定。所得的繞射輪廓係以下述的順序解 析。 首先，判定繞射輪廓的大部分是否係來自蝶形晶。具 體地，於繞射輪廓，在繞射角爲13〜15度範圍，繞射強 度最高之峰的強度爲C時，該峰的Cx〇.8程度之峰寬度D φ 爲1度以上的情況，判定該繞射輪廓的大部分係來自蝶形 晶之輪廓。 廣角X射線繞射輪廓的全部面積中佔有來自蝶形晶 之輪廓面積的比例係由下述式算出。 (i)繞射輪廓的大部分是否係來自蝶形晶之輪廓， 以上述方法判定。 (Π)判定繞射輪廓的大部分係來自蝶形晶之輪廓時 ，由以下的順序算出來自蝶形晶之輪廓面積的比例。 (iii)繞射輪廓以峰分離軟體處理，使蝶形晶之輪廓 -26- 201012834 與α晶之輪廓分離。作爲解析的軟體，使用理學（Rigaku )公司製JADE ( Ver· 5)軟體。從軟體所附之峰分離註 釋’繞射輪廓的峰分離所需要的輪廓特性，係pearson_ VI 1 = 1 .5。 (iv )爲了精密化，於實施例以及比較例，在峰分離 使用的繞射角度，係來自蝶形晶之14.6度與21.2度，以 及來自α晶之14.2度與16.7度與18_5度與21.4度，此 等爲固定値。 (ν)再者，作爲精密化的變數，選擇高度、半値寬 、計常數、非對稱，實施最佳化，算出在來自蝶形晶之 14.6度與21.2度具有峰之繞射輪廓之面積，藉由將其除 以繞射輪廓的總面積，求出來自蝶形晶之繞射輪廓的面積 比例。 (9)內部霧度 φ 內部霧度係將薄膜於石英玻璃製的容器（cell )，在 放入具有幾乎與聚丙烯系樹脂相同的折射率之液體的酞酸 二甲酯與測定的薄膜的狀態下，以根據JIS K-7136的方 法測定。 實施例1 [丙烯-1· 丁烯無規共聚物的製造] [預備聚合-1 ] 於內容積3L的附有攪拌機之SUS製高壓釜，添加充 -27- 201012834 分脫水、脫氣處理過之正己烷1.5L、三乙基鋁25毫莫耳 、第3 丁基正丙基二甲氧基矽烷2.5毫莫耳以及上述固體 觸媒成份15g，一邊保持高壓釜內的溫度約10 °C，一邊以 約30分鐘連續供應丙烯35g，進行預備聚合後，將預備 聚合漿體移至內容積150L的附有攪拌機之SUS製高壓釜 ，加入液狀丁烷100L，作爲預備聚合觸媒成份的漿體。 0 [聚合步驟-1] 於內容積144 0L的附有攪拌機之流動床反應器，連續 供給丙烯、1· 丁烯、氫氣、三乙基鋁、環己基乙基二甲氧 基矽烷及預備聚合觸媒成份的漿體，以聚合溫度65 °C、聚 合壓力l.IMPa、循環氣體風量150m3/小時、反應器內丙 烯濃度68.7莫耳％、1-丁烯濃度23.1莫耳％、氫氣濃度 8.16莫耳％、三乙基鋁的供應量31.6毫莫耳/小時、第3 丁基正丙基二甲氧基矽烷的供應量3.17毫莫耳/小時、預 © 備聚合觸媒成份的漿體之供應量依固體觸媒成份換算爲 0· 78 g/小時的條件，進行連續聚合。所得的聚合物（A·1 )以14.5公斤/小時從內容積325L的反應器取出，以甲 醇0.3L使固體觸媒失去活性後，在回收圓桶，60°C下進 行2小時的氮氣乾燥，回收丙烯-1-丁烯無規共聚物（1) 。共聚物（1)的物性表示於表1。共聚物（1)的來自0 烯的單體單位的含量爲80莫耳％，來自1-丁烯的單體單 位的含量爲20莫耳％。MFR爲8g/l〇分。 -28- 201012834 [光學薄膜的製作] 事先，將二軸延伸聚酯薄膜（東洋紡績（股）公司製 ’· 25 gm)由紡出機紡出，經由金屬製冷卻輥與矽製橡膠 輥所成挾壓部份，以捲取機捲取，以一般的擠出層合法的 通紙線進行通紙。在金屬製冷卻輥與矽製橡膠輥所成挾壓 部份正上方，配置450mm寬的T模頭的狀態下，將上述 所得的聚合物（1)使用5 0ιηιηφ擠出機以240°C熔融混練 φ ，使從T模頭的唇部擠出之熔融狀薄片層合於二軸延伸聚 酯薄膜上，以調溫成l〇°C之金屬製冷卻輥與調溫成10°c 之矽製橡膠輥挾壓，以線速度5m/分，使其冷卻固化後， 以捲取機捲取，得到厚度80 之原料薄膜。此時，在 冷卻輥與橡膠輥之間，沒有發生儲存所（bank)。原料薄 膜之大部份來自蝶形晶，X射線繞射輪廓的全部面積中， 來自蝶形晶的輪廓之面積比例爲95%。而且，於該原料 薄膜，球晶沒有發生。原料薄膜的面內相位差爲30nm， ® 內部HAZE (霧度）爲0.4%。 前述原料薄膜，製造結束後於23 °C保管20小時後， 該原料薄膜導入2組壓送輥間具有烤箱之長跨距縱延伸機 ，進行縱延伸。烤箱分爲2區’各區的長度爲lm。縱延 伸的條件爲第1區的溫度=90°C、第2區的溫度=94°C、 入口速度=5m/分、延伸倍率=1.5倍。縱延伸薄膜的厚度 爲73 μ m，面內相位差R〇爲630nm，厚度方向相位差Rth 爲 3 5 Onm。 進一步，將該縱延伸薄膜以拉幅法進行橫延伸’得到 -29- 201012834 光學薄膜。橫延伸的條件爲預熱區的溫度=125。(：、延伸 區的溫度=120°C、熱固定區的溫度=12(TC、延伸倍率= 4倍、橫延伸機的入口之夾頭間距離=150mm、出口之夾 頭間距離=600mm、線速度=lm/分。所得的光學薄膜的 厚度爲15#m，內部HAZE (霧度）爲0.2%，面內相位 差R〇爲ll〇nm，厚度方向相位差Rth爲100nm，光學的均 質性爲8nm。光學的均質性高，適合使用作爲相位差薄膜 實施例2 使用與實施例1相同之共聚物（1)，根據以下的方 法，製作（6)評價用光學薄膜。 [光學薄膜的製作] 將共聚物（1)投入汽缸溫度爲250°C之50ιηιηφ擠出 〇 機，進行熔融混練，以13kg/小時的擠出量，從附於前述 擠出機450 mm寬度的T模頭擠出。使被擠出的薄膜狀熔 融共聚物，藉由調溫成13°C之250 ιηιηφ冷卻輥與調溫成 13 °C之金屬套筒所成的外筒及其內部之彈性體輥所構成接 觸輥挾壓，使其冷卻，得到厚度1〇〇//m的原料薄膜。T 模頭的吐出口與輥之距離（空氣間隙）爲20mm，在冷卻 輥與接觸輥之間挾壓熔融狀薄片的距離爲l〇mm。此時， 在冷卻輥與接觸輥之間，沒有發生儲存所（bank)。原料 薄膜之大部份來自蝶形晶，X射線繞射輪廓的全部面積中 -30- 201012834 ，來自蝶形晶的輪廓之面積比例爲95%。而且，於該原 料薄膜，球晶沒有發生。原料薄膜的面內相位差爲30nm ，內部HAZE (霧度）爲0.4%。 前述原料薄膜，製造結束後於23 °C保管20小時後， 該薄膜（原料薄膜）導入2組壓送輥間具有烤箱之長跨距 縱延伸機，進行縱延伸。烤箱分爲2區，各區的長度爲 lm。縱延伸的條件爲第【區的溫度=90 °C、第2區的溫度 φ = 94°C、入口速度=5m/分、延伸倍率=1.5倍。縱延伸薄 膜的厚度爲90/zm，面內相位差R〇爲800nm，厚度方向 相位差Rth爲450nm。 進一步，將該縱延伸薄膜以拉幅法進行橫延伸，得到 光學薄膜。橫延伸的條件爲預熱區的溫度=128 °C、延伸 區的溫度=120°C、熱固定區的溫度=120t、延伸倍率= 4倍 '橫延伸機的入口之夾頭間距離=150mm、出口之夾 頭間距離=600mm、線速度=lm/分。所得的光學薄膜的 〇 厚度爲19 μιη，內部HAZE (霧度）爲0.2%，面內相位 差R〇爲90nm，厚度方向相位差Rth爲140nm，光學的均 質性爲l〇nm。光學的均質性高，適合使用作爲相位差薄 膜。 比較例1 [丙烯-1-丁烯無規共聚物的製造] 以與實施例1的「預備聚合-1」記載之相同方法實施 預備聚合。 -31 - 201012834Current 10 0mA Divergence slit 1.0° Scatter slit 1.0° -24- 201012834 Receiving slit 0.15° Measuring range 2 0 : 5~3 5 ° Wide-angle X-ray winding In the emission spectrum, in the region where the diffraction angle 20 is 16.0 to 17.0°, the diffraction peak intensity shows a maximum diffraction angle of 2 Θ (wo), and the diffraction angle 20 is 12.5 to 15.0°. The diffraction peak intensity shows a very large diffraction angle of 20 (11Q). Substituting 0 (040) and 0 (110) into Θ of the following formula d = nX/2sin0 (η = 1, λ = 1.54 Α), and obtaining the lattice spacing of each crystal lattice (1 (040) 'duiO:), The b-axis and the a-axis length of the crystal lattice constant were obtained by the following formula. B-axis length=4d(〇4〇) a-axis length=b-axis length xd(ii〇)/(b-axis length 2-d(ii〇)2)1/2 (6) in-plane phase difference Ro, thickness direction The phase difference Rth film has an in-plane retardation in the axial direction of the film having a refractive index of nx, and the in-plane forward 〇 phase axis direction (in the plane perpendicular to the retardation phase axis) has a refractive index of ny, and the thickness direction has a refractive index of nz. The thickness d, the in-plane phase difference (R〇), and the thickness direction phase difference (Rth) were measured and defined by the following formulas (I) and (II), respectively. R〇=(nx-ny)xd (I) Rth = [(nx + ny)/2-nz] xd (II) Using a phase difference measuring device (Oji Scientific Instruments Co., Ltd., KOBRA-WPR) The film obtained by the one-to-one extension of the -25-201012834 one-axis stretching method of 1.5 times and four times of the horizontal direction was measured for 16 times with a phase difference of 300 mm, and the average was calculated. (7) Optical homogeneity The difference between the maximum 値 and the minimum R of RQ measured in the above (4) is used as an indicator of optical homogeneity. The smaller the difference, the higher the optical homogeneity and the better. e (8) Wide-angle X-ray diffraction The wide-angle X-ray diffraction system of the raw material film is measured at a diffraction angle (20) of 5 to 35 degrees. The resulting diffraction profile was analyzed in the following order. First, it is determined whether most of the diffraction profile is from a butterfly crystal. Specifically, in the diffraction profile, when the diffraction angle is in the range of 13 to 15 degrees and the intensity of the peak having the highest diffraction intensity is C, the peak width D φ of the peak of Cx 〇.8 is 1 degree or more. It is determined that most of the diffraction profile is from the contour of the butterfly crystal. The ratio of the area of the contour of the butterfly crystal occupied by the entire area of the wide-angle X-ray diffraction profile is calculated by the following equation. (i) Whether most of the diffraction profile is derived from the contour of the butterfly crystal, as determined by the above method. (Π) When it is determined that most of the diffraction profile is derived from the contour of the butterfly crystal, the ratio of the contour area from the butterfly crystal is calculated in the following order. (iii) The diffraction profile is treated with a peak separation software to separate the contour of the butterfly crystal -26-201012834 from the contour of the alpha crystal. As the software to be analyzed, JADE (Ver. 5) software manufactured by Rigaku Co., Ltd. was used. From the peak attached to the software, the contour characteristics required for the peak separation of the diffraction profile are: pearson_ VI 1 = 1.5. (iv) For the sake of precision, in the examples and comparative examples, the diffraction angle used in peak separation is from 14.6 degrees and 21.2 degrees of the butterfly crystal, and 14.2 degrees and 16.7 degrees and 18_5 degrees and 21.4 from the alpha crystal. Degree, this is fixed. (v) In addition, as a precision variable, the height, the half width, the gauge constant, and the asymmetry are selected, and optimization is performed, and the area of the diffraction profile having peaks at 14.6 degrees and 21.2 degrees from the butterfly crystal is calculated. The area ratio from the diffraction profile of the butterfly crystal is determined by dividing it by the total area of the diffraction profile. (9) Internal haze φ Internal haze is a film made of quartz glass in a container made of quartz glass, and a dimethyl phthalate having a liquid having a refractive index almost the same as that of the polypropylene resin and a measured film. In the state, it was measured by the method according to JIS K-7136. Example 1 [Production of Propylene-1·Butylene Random Copolymer] [Preparation Polymerization-1] In an autoclave made of SUS with a stirrer with an internal volume of 3 L, a dehydration and degassing treatment was carried out by adding -27-201012834. 1.5 L of n-hexane, 25 mmol of triethylaluminum, 2.5 mmol of 3 butyl-n-propyldimethoxydecane and 15 g of the above solid catalyst component while maintaining the temperature in the autoclave at about 10 ° C While continuously supplying 35 g of propylene for about 30 minutes and performing preliminary polymerization, the prepolymerized slurry was transferred to a SUS autoclave equipped with a stirrer having an internal volume of 150 L, and 100 L of liquid butane was added as a preliminary polymerization catalyst component. Slurry. 0 [Polymerization step-1] Continuously supply propylene, 1·butene, hydrogen, triethylaluminum, cyclohexylethyldimethoxydecane and preliminary polymerization in a fluidized bed reactor with a mixer of 144 0L. The slurry of the catalyst component has a polymerization temperature of 65 ° C, a polymerization pressure of 1. IMPa, a circulating gas volume of 150 m 3 /hr, a propylene concentration of 68.7 mol% in the reactor, a 1-butene concentration of 23.1 mol%, and a hydrogen concentration of 8.16. Moir%, triethylaluminum supply 31.6 mmol/hr, 3 butyl-n-propyldimethoxydecane supply 3.17 mmol/hr, pre-polymerized catalyst mixture The supply amount was continued by converting the solid catalyst component to 0·78 g/hr. The obtained polymer (A·1) was taken out from a reactor having an internal volume of 325 L at 14.5 kg/hr, and the solid catalyst was deactivated with 0.3 L of methanol, and then subjected to nitrogen drying at 60 ° C for 2 hours in a recovery drum. , recovery of propylene-1-butene random copolymer (1). The physical properties of the copolymer (1) are shown in Table 1. The content of the monomer unit derived from the olefin of the copolymer (1) was 80 mol%, and the content of the monomer unit derived from 1-butene was 20 mol%. The MFR is 8 g/l. -28- 201012834 [Production of optical film] A biaxially stretched polyester film (25 gm manufactured by Toyobo Co., Ltd.) was spun from a spinning machine, and a metal cooling roll and a rubber roller were used. The rolled portion is taken up by a coiler, and the paper is passed through a normal extruded layer of paper. The polymer (1) obtained above was melted at 240 ° C using a 50 mm ηηηφ extruder in a state where a 450 mm wide T die was placed directly above the rolled portion of the metal cooling roll and the tantalum rubber roll. Kneading φ so that the molten sheet extruded from the lip of the T die is laminated on the biaxially stretched polyester film, and the metal cooling roll adjusted to a temperature of 10 ° C is adjusted to 10 ° C. The rubber roller was pressed and cooled at a linear velocity of 5 m/min, and then taken up by a coiler to obtain a raw material film having a thickness of 80. At this time, no bank occurred between the cooling roller and the rubber roller. Most of the raw film is from a butterfly crystal, and the area ratio of the contour of the butterfly crystal is 95% in the entire area of the X-ray diffraction profile. Further, in the raw material film, spherulites did not occur. The in-plane phase difference of the raw material film was 30 nm, and the internal HAZE (haze) was 0.4%. After the completion of the production, the raw material film was stored at 23 ° C for 20 hours, and then the raw material film was introduced into a long-span longitudinal stretching machine having an oven between two sets of nip rolls to perform longitudinal stretching. The oven is divided into 2 zones' each zone has a length of lm. The conditions for the longitudinal stretching were the temperature of the first zone = 90 ° C, the temperature of the second zone = 94 ° C, the inlet velocity = 5 m / min, and the stretching ratio = 1.5 times. The longitudinally stretched film had a thickness of 73 μm, an in-plane retardation R〇 of 630 nm, and a thickness direction retardation Rth of 3 5 Onm. Further, the longitudinally stretched film was laterally stretched by a tenter method to obtain an optical film of -29 to 201012834. The condition of the transverse extension is the temperature of the preheating zone = 125. (:, the temperature of the extension zone = 120 ° C, the temperature of the heat-fixing zone = 12 (TC, extension ratio = 4 times, the distance between the chucks of the entrance of the horizontal extension machine = 150 mm, the distance between the chucks of the outlet = 600 mm, Linear velocity = lm / min. The obtained optical film has a thickness of 15 #m, an internal HAZE (haze) of 0.2%, an in-plane retardation R〇 of ll 〇 nm, and a thickness direction retardation Rth of 100 nm, optical homogenization. The optical property is 8 nm. The optical homogeneity is high, and it is suitable to use as the retardation film. Example 2 Using the same copolymer (1) as in Example 1, (6) an optical film for evaluation was produced by the following method. Manufacture] The copolymer (1) was placed in a 50 ηηηηφ extruder with a cylinder temperature of 250 ° C, and melt-kneaded, and extruded at a rate of 13 kg/hr from a T die attached to the 450 mm width of the aforementioned extruder. The outer tube of the extruded film-like molten copolymer, which is tempered to a temperature of 13 ° C and a metal sleeve adjusted to a temperature of 13 ° C, and an elastomer roll thereof The contact roller is pressed and cooled to obtain a raw material film having a thickness of 1 〇〇//m. The spit of the T die The distance between the mouth and the roller (air gap) is 20 mm, and the distance between the cooling roller and the contact roller to roll the molten sheet is 10 mm. At this time, no storage place occurs between the cooling roller and the contact roller (bank The majority of the raw material film is from the butterfly crystal, the entire area of the X-ray diffraction profile is -30-201012834, and the area ratio of the contour from the butterfly crystal is 95%. Moreover, in the raw material film, the spherulites are not The in-plane phase difference of the raw material film was 30 nm, and the internal HAZE (haze) was 0.4%. After the raw material film was stored at 23 ° C for 20 hours after the completion of the production, the film (raw material film) was introduced into two sets of nip rolls. Long-span longitudinal extension machine with oven for longitudinal extension. The oven is divided into 2 zones, each zone has a length of lm. The condition of longitudinal extension is the temperature of zone [90 °C, the temperature of zone 2 φ = 94 ° C, inlet speed = 5 m / min, and stretching ratio = 1.5 times. The thickness of the longitudinally stretched film was 90 / zm, the in-plane retardation R 〇 was 800 nm, and the thickness direction retardation Rth was 450 nm. Further, the longitudinal extension The film was stretched laterally by a tenter method to obtain an optical film. The conditions for stretching are: temperature of preheating zone = 128 °C, temperature of extension zone = 120 °C, temperature of heat-fixing zone = 120 t, extension ratio = 4 times 'the distance between the ends of the cross-extension machine = 150 mm, The distance between the chucks at the exit is 600 mm, and the linear velocity is lm/min. The obtained optical film has a crucible thickness of 19 μm, an internal HAZE (haze) of 0.2%, an in-plane retardation R〇 of 90 nm, and a thickness direction retardation. Rth is 140 nm and optical homogeneity is l〇nm. High optical homogeneity, suitable for use as a retardation film. Comparative Example 1 [Production of propylene-1-butene random copolymer] The preliminary polymerization was carried out in the same manner as described in "Preparation polymerization-1" of Example 1. -31 - 201012834
除聚合溫度80°C、聚合壓力1.8MPa、反應器 濃度97.3莫耳％、1-丁烯濃度1.1莫耳％、氫氣潘 莫耳％、三乙基鋁的供應量48毫莫耳/小時、第3 丙基二甲氧基矽烷的供應量6毫莫耳/小時以外， 行與實施例1相同的聚合，回收丙烯-1-丁烯無規 • (2)。共聚物（2)中來自丙烯的單體單位的含J 莫耳％，來自1-丁烯的單體單位的含量爲2莫 ❿ Tm=158°C，a 軸長度= 6.64A，b 軸長度= 21.28A， 2g/10 分。 [光學薄膜的製作] 除使用丙烯-1-丁烯無規共聚物（2)取代共赛 )，以擠出機進行熔融混練的溫度爲300°C以外， 施例1相同方式製作原料薄膜。原料薄膜之大部份 形晶，X射線繞射輪廓的全部面積中，來自蝶形晶 Q 之面積比例爲97 %。而且，於該原料薄膜，球晶 生。原料薄膜的面內相位差爲30nm，內部HAZE )爲 0.4%。 前述原料薄膜，製造結束後於23 °C保管20小 該原料薄膜導入2組壓送輥間具有烤箱之長跨距縱 ，進行縱延伸。烤箱分爲2區，各區的長度爲lm 伸的條件爲第1區的溫度=142 °C、第2區的溫度： 、入口速度=5m/分、延伸倍率=1.5倍。縱延伸薄 度爲68 /z m，面內相位差R〇爲700nm，厚度方向 內丙烯 【度1.6 丁基正 藉由進 共聚物 t爲98 耳％。 MFR = 【物（1 以與實 來自蝶 的輪廓 沒有發 (霧度 時後， 延伸機 。縱延 =146〇C 膜的厚 相位差 -32- 201012834In addition to the polymerization temperature of 80 ° C, the polymerization pressure of 1.8 MPa, the reactor concentration of 97.3 mol%, the 1-butene concentration of 1.1 mol%, the hydrogen panmole%, the supply of triethylaluminum of 48 mmol / h, The same polymerization as in Example 1 was carried out except that the supply amount of the third propyl dimethoxydecane was 6 mmol/hr, and the propylene-1-butene was recovered randomly (2). In the copolymer (2), the monomer unit derived from propylene contains J mole %, the monomer unit content derived from 1-butene is 2 ❿ Tm = 158 ° C, the length of the a-axis is 6.64 A, and the length of the b-axis = 21.28A, 2g/10 points. [Production of Optical Film] A raw material film was produced in the same manner as in Example 1 except that the propylene-1-butene random copolymer (2) was used in place of the co-race), and the temperature at which the melt-kneading was carried out in an extruder was 300 °C. Most of the raw material film is shaped, and the area ratio of the butterfly crystal Q is 97% in the entire area of the X-ray diffraction profile. Further, in the raw material film, spherulites are formed. The in-plane phase difference of the raw material film was 30 nm, and the internal HAZE was 0.4%. After the completion of the production, the raw material film was stored at 23 ° C for 20 hours. The raw material film was introduced into the two sets of nip rolls to have a long span of the oven and longitudinally extended. The oven is divided into 2 zones, and the length of each zone is lm. The temperature of the first zone is 142 °C, the temperature of the second zone: inlet velocity = 5 m/min, and the extension ratio = 1.5 times. The longitudinal elongation was 68 / z m, the in-plane retardation R 〇 was 700 nm, and the propylene in the thickness direction was 1.6 butyl by the copolymer t. MFR = [object (1) and the actual contour from the butterfly is not emitted (after the haze, the extension machine. The delay = 146 〇 C film thickness phase difference -32- 201012834
Rth 爲 4 1 Onm ° 進一步，將該縱延伸薄膜以拉幅法進行橫延伸，得到 光學薄膜。橫延伸的條件爲預熱區的溫度=158 °C、延伸 區的溫度=148°C、熱固定區的溫度=148°C、延伸倍率= 4倍、橫延伸機的入口之夾頭間距離=150mm、出口之夾 頭間距離=600mm、線速度=lm/分。所得的光學薄膜的 厚度爲17#ιη，內部HAZE (霧度）爲0.1%，面內相位 差R〇爲130nm，厚度方向相位差Rth爲130nm，光學的均 質性爲5 4nm，光學的均質性低。 比較例2 [丙烯-1· 丁烯無規共聚物的製造] 以與實施例1的「預備聚合-1」記載之相同方法實施 預備聚合。 除於內容積1440L的附有攪拌機之流動床反應器，連 φ 續供給丙烯、乙烯、氫氣、三乙基鋁、環己基乙基二甲氧 基矽烷及預備聚合觸媒成份的漿體，以聚合溫度80 °C、聚 合壓力l.OMPa、反應器內丙烯濃度98.5莫耳％、乙烯濃 度1.2 5莫耳％、氫氣濃度0.25莫耳％、三乙基鋁的供應 量50毫莫耳/小時、第3 丁基正丙基二甲氧基矽烷的供應 量5毫莫耳/小時以外，藉由進行與實施例1相同的聚合 ，回收丙烯·乙烯無規共聚物（3)。共聚物（3)中來自 丙烯的單體單位的含量爲99.3莫耳％，來自乙烯的單體 單位的含量爲0.7莫耳％。Tm=159°C，結晶熔解熱量 -33- 201012834 9 0 J / g，a 軸長度=6.6 4 A ’ b 軸長度=2 1.1 2 A，M F R = 2g/10 分。 [光學薄膜的製作] 除使用丙烯-乙烯無規共聚物（3)取代共聚物（1) ，以擠出機進行熔融混練的溫度爲3 00 °C以外，以與實施 例1相同方式製作原料薄膜。原料薄膜之大部份來自蝶形 φ 晶，X射線繞射輪廓的全部面積中，來自蝶形晶的輪廓之 面積比例爲94%。而且，於該原料薄膜，球晶沒有發生 。原料薄膜的面內相位差爲30nm，內部HAZE (霧度） 爲 0.5 %。 前述原料薄膜，製造結束後於23 °C保管20小時後， 該原料薄膜導入2組壓送輥間具有烤箱之長跨距縱延伸機 ，進行縱延伸。烤箱分爲2區，各區的長度爲lm。縱延 伸的條件爲第1區的溫度=142°C、第2區的溫度=146°C 〇 、入口速度=5m/分、延伸倍率=1.5倍。縱延伸薄膜的厚 度爲69#m，面內相位差R〇爲800nm，厚度方向相位差 Rth 爲 4 1 Onm。 進一步，將該縱延伸薄膜以拉幅法進行橫延伸，得到 光學薄膜。橫延伸的條件爲預熱區的溫度=158 °C、延伸 區的溫度=148°C、熱固定區的溫度=148°C、延伸倍率= 4倍、橫延伸機的入口之夾頭間距離=150mm、出口之夾 頭間距離= 600mm、線速度=lm/分。所得的光學薄膜的 厚度爲17μπι，內部HAZE (霧度）爲0.2%，面內相位 -34- 201012834 差R〇爲180nm，厚度方向相位差Rth爲150nm，光學的均 質性爲75nm，光學的均質性低。 [表1] 熔解峰溫度 ro 結晶化熱量 (J/g) 結晶晶格常數(A) a軸長度 b軸長度 共聚物⑴ 128 54 6.77 22.08 共聚物⑵ 158 120 6.64 21.28 共聚物（3) 159 90 6.64 21.12 _ 產業上的利用可能性 根據本發明，提供可以低成本製造之光學的均質性佳 之光學薄膜。 【圖式簡單說明】 圖1係說明廣角X射線繞射輪廓的解析方法之圖， 圖中符號1表示CxO.8程度之峰寬（度）。 ❿ 【主要元件符號說明】 1: CxO.8程度之峰寬（度） -35-Rth was 4 1 Onm ° Further, the longitudinally stretched film was laterally stretched by a tenter method to obtain an optical film. The conditions of the lateral extension are the temperature of the preheating zone = 158 ° C, the temperature of the extension zone = 148 ° C, the temperature of the heat fixing zone = 148 ° C, the stretching ratio = 4 times, the distance between the chucks of the entrance of the transverse stretching machine =150mm, the distance between the chucks of the outlet = 600mm, the line speed = lm / min. The obtained optical film had a thickness of 17# ηη, an internal HAZE (haze) of 0.1%, an in-plane retardation R〇 of 130 nm, a thickness direction phase difference Rth of 130 nm, an optical homogeneity of 54 nm, and optical homogeneity. low. Comparative Example 2 [Production of propylene-1·butene random copolymer] The preliminary polymerization was carried out in the same manner as described in "Preparation polymerization-1" of Example 1. In addition to a 1440 L inner volume flow reactor equipped with a stirrer, a slurry of propylene, ethylene, hydrogen, triethylaluminum, cyclohexylethyldimethoxydecane, and a prepolymerized catalyst component is continuously supplied. The polymerization temperature was 80 °C, the polymerization pressure was 1.0 MPa, the propylene concentration in the reactor was 98.5 mol%, the ethylene concentration was 1.2 5 mol%, the hydrogen concentration was 0.25 mol%, and the supply amount of triethylaluminum was 50 mmol/hr. The propylene/ethylene random copolymer (3) was recovered by carrying out the same polymerization as in Example 1 except that the supply amount of the third butyl-n-propyldimethoxydecane was 5 mmol/hr. The content of the monomer unit derived from propylene in the copolymer (3) was 99.3 mol%, and the content of the monomer unit derived from ethylene was 0.7 mol%. Tm = 159 ° C, heat of crystal melting -33 - 201012834 9 0 J / g, a shaft length = 6.6 4 A 'b shaft length = 2 1.1 2 A, M F R = 2g/10 minutes. [Production of Optical Film] A raw material was produced in the same manner as in Example 1 except that the propylene-ethylene random copolymer (3) was used in place of the copolymer (1) and the temperature at which the melt-kneading was carried out in an extruder was 300 °C. film. Most of the raw material film is derived from butterfly φ crystal, and the area ratio of the outline of the butterfly crystal is 94% in the entire area of the X-ray diffraction profile. Further, in the raw material film, spherulites did not occur. The in-plane phase difference of the raw material film was 30 nm, and the internal HAZE (haze) was 0.5%. After the completion of the production, the raw material film was stored at 23 ° C for 20 hours, and then the raw material film was introduced into a long-span longitudinal stretching machine having an oven between two sets of nip rolls to perform longitudinal stretching. The oven is divided into 2 zones, each zone having a length of lm. The conditions for the longitudinal extension were the temperature of the first zone = 142 ° C, the temperature of the second zone = 146 ° C 〇 , the inlet velocity = 5 m / min, and the stretching ratio = 1.5 times. The longitudinally stretched film had a thickness of 69 #m, an in-plane retardation R〇 of 800 nm, and a thickness direction phase difference Rth of 4 1 Onm. Further, the longitudinally stretched film was laterally stretched by a tenter method to obtain an optical film. The conditions of the lateral extension are the temperature of the preheating zone = 158 ° C, the temperature of the extension zone = 148 ° C, the temperature of the heat fixing zone = 148 ° C, the stretching ratio = 4 times, the distance between the chucks of the entrance of the transverse stretching machine =150mm, the distance between the outlets of the outlet = 600mm, the line speed = lm / min. The obtained optical film had a thickness of 17 μm, an internal HAZE (haze) of 0.2%, an in-plane phase of -34 to 201012834, a difference R 〇 of 180 nm, a thickness direction phase difference Rth of 150 nm, and an optical homogeneity of 75 nm, optical homogenization. Low sex. [Table 1] Melting peak temperature ro Crystallizing heat (J/g) Crystal lattice constant (A) a-axis length b-axis length copolymer (1) 128 54 6.77 22.08 Copolymer (2) 158 120 6.64 21.28 Copolymer (3) 159 90 6.64 21.12 _ Industrial Applicability According to the present invention, an optical homogenization optical film which can be manufactured at low cost is provided. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a method of analyzing a wide-angle X-ray diffraction profile, in which the symbol 1 indicates the peak width (degree) of CxO.8. ❿ [Main component symbol description] 1: CxO.8 degree peak width (degrees) -35-