發明所欲解決之問題
本發明的目的在於提供具有高透明度和低表面電阻的聚醯胺酸組合物和聚醯亞胺薄膜。
解決問題之技術手段
聚醯亞胺樹脂在由芳族二酐與芳族二胺或芳族二異氰酸酯聚合製備聚醯胺酸衍生物後，經通過固化的醯亞胺化製備而成。
聚醯亞胺基於剛性芳香主鏈，因此具有優異的熱穩定性。但是，與芳香族主鏈所帶來的高熱穩定性相反，透明性降低很多，因此，在電子材料領域，尤其是要求高透明性的顯示領域的使用受到限制。尤其，最近進行向聚醯亞胺賦予導電性來應用於電子工業領域中的研究，但是提高添加有導電材料的聚醯亞胺的透明性更加困難。
根據本發明的聚醯胺酸組合物通過將包含二酐單體和二胺單體作為聚合單元的聚合物和相容性優異的共軛導電高分子包括在聚醯胺酸組合物中，可以提供在具有高透射率的同時具有優異導電性的聚醯亞胺。
另外，在根據本發明的聚醯胺酸組合物中，共軛導電高分子與溶劑的作用效果優異，因此共軛導電高分子的分散性優異，通過將該共軛導電高分子固化而製備的聚醯亞胺包含少含量的共軛導電高分子並具有優異的導電性。
尤其，根據本發明的聚醯胺酸組合物具有如上所述的高透明度和導電性，還保持聚醯亞胺特有的優異的熱特性和機械特性。
本發明涉及一種聚醯胺酸組合物。上述聚醯胺酸組合物包含具有衍生自二酐單體和二胺單體的聚合物單元的聚合物和共軛導電高分子。
上述共軛導電高分子統稱具有以一個單鍵為中心由原子價電子形成多鍵的結構的高分子。具體而言，上述共軛導電高分子可以是具有雙鍵和單鍵或三鍵和單鍵交替連接的化學結構的高分子。
根據本發明的共軛導電高分子的實例可以包括聚芴(polyfluorene)、聚苯(polyphenylene)、聚芘(polypyrene)、聚薁(polyazulene)、聚萘(polynaphthalene)、聚乙炔(polyacetylene)、聚噻吩(polythiophene)、聚(3,4-乙烯二氧噻吩)(PEDOT)、聚(對苯硫醚)(poly(p-phenylene sulfide)、聚吡咯(polypyrrole)、聚咔唑(polycarbazole)、聚吲哚(polyindole)、聚氮雜卓(polyazepine)或聚苯胺(polyaniline)。
當構成根據本發明的聚醯胺酸組合物的聚合物的聚合單元的二酐單體和二胺單體包括芳族二酐單體和/或芳族二胺單體時，從相容性的觀點來看，共軛導電高分子可以包括芳環或雜原子。上述共軛導電高分子的實例包括選自由聚噻吩(polythiophene)、聚(3,4-乙烯二氧噻吩)(PEDOT)、聚(對苯硫醚)(poly(p-phenylene sulfide)、聚吡咯(polypyrrole)、聚咔唑(polycarbazole)、聚吲哚(polyindole)、聚氮雜卓(polyazepine)及聚苯胺(polyaniline)組成的組中的至少一種。
另外，根據本發明的聚醯胺酸組合物的包括二酐單體和二胺單體的聚合物包括氮原子，因此從分散性和相容性的觀點考慮，上述共軛導電高分子的雜原子優選為氮，因此，根據本發明的共軛導電高分子可以為選自由聚吡咯(polypyrrole)、聚咔唑(polycarbazole)、聚吲哚(polyindole)、聚氮雜卓(polyazepine)及聚苯胺(polyaniline)組成的組中的至少一種。尤其，從提高固化後的聚醯亞胺的透明性的觀點出發，在芳香環中含有氮原子的低分子量的聚吡咯是優選的。
根據本發明的共軛導電高分子的膜電導率(乾燥鑄膜電導率，Dried Cast Film Conductivity)可以為0.005S/cm以上。例如，上述共軛導電高分子的膜電導率可以為0.006 S/cm以上、0.007S/cm以上、0.008S/cm以上、0.009S/cm以上、或0.01S/cm以上。當共軛導電高分子的膜電導率滿足如上所述的膜電導率時，包含上述共軛導電高分子的聚醯胺酸組合物可以具有提高的電導率。
此時，基於聚醯胺酸組合物的總重量，上述共軛導電高分子的含量可以為0.01重量%至1重量%。具體而言，上述共軛導電高分子的含量可以為0.05重量%至1重量%、0.05重量%至0.9重量%、0.1重量%至1重量%、0.1重量%至0.7重量%、0.2重量%至1重量%、0.2重量%至0.9重量%、0.2重量%至0.7重量%、0.3重量%至1重量%、0.3重量%至0.9重量%、0.3重量%至0.7重量%、0.4重量%至0.7重量%或0.4重量%至0.6重量%。當根據本發明的聚醯胺酸組合物以如上所述的含量包含共軛導電高分子時，具有優異的透明度和優異的導電性。
根據本發明的聚醯胺酸組合物在固化後按照ASTM D257測得的表面電阻可以為1.0×10
13Ω/□以下。此外，根據本發明的聚醯胺酸組合物在固化後在380nm至780nm波長下的10μm厚度的平均透光率可以為50%以上。本發明中記載的各種物理性能的具體測定方法和測定條件在下面將描述的實驗例中詳細說明。
具體而言，根據本發明的聚醯胺酸組合物在固化後在380nm至780nm波長下的10μm厚度的平均透光率可以為50%以上。例如，上述透光率可以為52%以上、54%以上、56%以上、58%以上、60%以上、62%以上、64%以上、66%以上、68%以上、70%以上、75%以上、80%以上、82%以上、84%以上、或85%以上，其上限不受特別限制，可以為90%以下。可以使用紫外/可見分光光度計(UV-Vis Spectrophotometer)來測定上述透光率。
此外，根據本發明的聚醯胺酸組合物的按照ASTM D257測得的表面電阻可以為1.0×10
13Ω/□以下。例如，上述表面電阻可以為6.0×10
12Ω/□以下、2.0×10
12Ω/□以下、5.0×10
11Ω/□以下或2.0×10
11Ω/□以下，具體而言，上述表面電阻可以為1.0×10
11至1.0×10
13Ω/□、1.0×10
11至6.0×10
12Ω/□、1.0×10
11至2.0×10
12Ω/□或1.0×10
11至1.0×10
12Ω/□。
本發明通過同時滿足如上所述的透光率和表面電阻，可以提供具有高透明度和優異導電性的聚醯胺酸組合物。
可用於製備聚醯胺酸溶液的二酐單體可以為芳香族四羧酸二酐，上述芳香族四羧酸二酐的實例可以包括均苯四甲酸二酐(或PMDA)、3,3',4,4'-聯苯四羧酸二酐(或BPDA)、2,3,3',4'-聯苯四甲酸二酐(或a-BPDA)、氧二苯二甲酸二酐(或ODPA)、二苯碸-3,4,3',4'-四羧酸二酐(或DSDA)、雙(3,4-二羧基苯基)硫醚二酐、2,2-雙(3,4-二羧基苯基)-1,1,1,3,3,3-六氟丙烷二酐、2,3,3',4'-二苯甲酮四羧酸二酐、3,3',4,4'-二苯甲酮四羧酸二酐(或BTDA)、雙(3,4-二羧基苯基)甲烷二酐、2,2-雙(3,4-二羧基苯基)丙烷二酐、對亞苯基雙(偏苯三酸單酯酸酐)、對亞聯苯雙(偏苯三酸單酯酸酐)、間三聯苯-3,4,3',4'-四羧酸二酐、對三聯苯-3,4,3',4'-四羧酸二酐、1,3-雙(3,4-二羧基苯氧基)苯二酐、1,4-雙(3,4-二羧基苯氧基)苯二酐、1,4-雙(3,4-二羧基苯氧基)聯苯二酐、2,2-雙[(3,4-二羧基苯氧基)苯基]丙烷二酐(BPADA)、2,3,6,7-萘四甲酸二酐、1,4,5,8-萘四甲酸二酐或4,4'-(2,2-六氟異亞丙基)二鄰苯二甲酸二酐等。
根據需要，上述二酐單體可以單獨使用或兩種以上組合使用，例如，可以包括選自由均苯四酸二酐(PMDA)、3,3',4,4'-聯苯四甲酸二酐(s-BPDA)、2,3,3',4'-聯苯四甲酸二酐(a-BPDA)、3,3',4,4'-二苯甲酮四羧酸二酐(BTDA)、氧二苯二甲酸二酐(ODPA)、4,4-(六氟異亞丙基)二苯二甲酸酐(6-FDA)及對苯撐雙(偏苯三酸酐)(TAHQ)組成的組中的至少一種。
在本發明的一個實施方式中，上述二酐單體可以包括具有一個苯環的二酐單體和具有兩個或更多個苯環的二酐單體。上述具有一個苯環的二酐單體和上述具有兩個或更多個苯環的二酐單體分別可以以20摩爾%至60摩爾%和40摩爾%至90摩爾%；25摩爾%至55摩爾%和45摩爾%至80摩爾%；或35摩爾%至53摩爾%和48摩爾%至75摩爾%的摩爾比被包含。在本發明中，通過含有上述二酐單體，在具有優異的黏合力的同時，能夠實現所期望的水平的機械性能。
此外，可用於製備聚醯胺酸溶液的二胺單體為芳香族二胺，可分類如下並舉例說明。
1)作為如1,4-二氨基苯(或對苯二胺，PDA)、1,3-二氨基苯、2,4-二氨基甲苯、2,6-二氨基甲苯或3,5-二氨基苯甲酸(或DABA)等的在結構中具有一個苯核的二胺，具有相對剛性的結構的二胺；
2)如4,4'-二氨基二苯甲烷(亞甲基二胺)、3,3'-二甲基-4,4'-二氨基聯苯、2,2'-二甲基-4,4'-二氨基聯苯、2,2'-雙(三氟甲基)-4,4'-二氨基聯苯、3,3'-二甲基-4,4'-二氨基二苯甲烷、3,3'-二羧基-4,4'-二氨基二苯甲烷、3,3',5,5'-四甲基-4,4'-二氨基二苯甲烷、雙(4-氨基苯基)硫醚、4,4'-二氨基苯甲醯苯胺、3,3'-二氯聯苯胺、3,3'-二甲基聯苯胺(或鄰聯苯胺)、2,2'-二甲基聯苯胺(或間甲苯胺)、3,3'-二甲氧基聯苯胺、2,2'-二甲氧基聯苯胺、3,3'-二氨基二苯醚、3,4'-二氨基二苯醚、4,4'-二氨基二苯醚(或氧雙苯胺、ODA)、3,3'-二氨基二苯硫醚、3,4'-二氨基二苯硫醚、4,4'-二氨基二苯硫醚、3,3'-二氨基二苯碸、3,4'-二氨基二苯碸、4,4'-二氨基二苯碸、3,3'-二氨基二苯甲酮、4,4'-二氨基二苯甲酮、3,3'-二氨基-4,4'-二氯二苯甲酮、3,3'-二氨基-4,4'-二甲氧基二苯甲酮、3,3'-二氨基二苯甲烷、3,4'-二氨基二苯甲烷、4,4'-二氨基二苯基甲烷、2,2-雙(3-氨基苯基)丙烷、2,2-雙(4-氨基苯基)丙烷、2,2-雙(3-氨基苯基)-1,1,1,3,3, 3-六氟丙烷、2,2-雙(4-氨基苯基)-1,1,1,3,3,3-六氟丙烷、3,3'-二氨基二苯亞碸、3,4'-二氨基二苯亞碸或4,4'-二氨基二苯亞碸等的在結構中具有兩個苯核的二胺；
3)如1,3-雙(3-氨基苯基)苯、1,3-雙(4-氨基苯基)苯、1,4-雙(3-氨基苯基)苯、1,4-雙(4-氨基)苯基)苯、1,3-雙(4-氨基苯氧基)苯、1,4-雙(3-氨基苯氧基)苯(或TPE-Q)、1,4-雙(4-氨基苯氧基)苯(或TPE-Q)、1,3-雙(3-氨基苯氧基)-4-三氟甲基苯、3,3'-二氨基-4-(4-苯基)苯氧基二苯甲酮、3,3'-二氨基-4,4'-二(4-苯基苯氧基)二苯甲酮、1,3-雙(3-氨基苯硫醚)苯、1,3-雙(4-氨基苯硫醚)苯、1,4-雙(4-氨基苯硫醚)苯、1,3-雙(3-氨基苯碸)苯、1,3-雙(4-氨基苯碸)苯、1,4-雙(4-氨基苯碸)苯、1,3-雙[2-(4-氨基苯基)異丙基]苯、1,4-雙[2-(3-氨基苯基)異丙基]苯或1,4-雙[2-(4-氨基苯基)異丙基]苯等的在結構中具有三個苯核的二胺；
4)如3,3'-雙(3-氨基苯氧基)聯苯、3,3'-雙(4-氨基苯氧基)聯苯、4,4'-雙(3-氨基苯氧基)聯苯、4,4'-雙(4-氨基苯氧基)聯苯，雙[3-(3-氨基苯氧基)苯基]醚，雙[3-(4-氨基苯氧基)苯基]醚，雙[4-(3-氨基苯氧基)苯基]醚，雙[4-(4-氨基苯氧基)苯基]醚，雙[3-(3-氨基苯氧基)苯基]酮，雙[3-(4-氨基苯氧基)cy)苯基]酮，雙[4-(3-氨基苯氧基)苯基]酮，雙[4-(4-氨基苯氧基)苯基]酮，雙[3-(3-氨基苯氧基)苯基]硫化物，雙[3-(4-氨基苯氧基)苯基]硫化物，雙[4-(3-氨基苯氧基)苯基]硫化物，雙[4-(4-氨基苯氧基)苯基]硫化物、雙[3-(3-氨基苯氧基)苯基]碸、雙[3-(4-氨基苯氧基)苯基]碸、雙[4-(3-氨基苯氧基)苯基]碸、雙[4-(4-氨基苯氧基)cy)苯基]碸、雙[3-(3-氨基苯氧基)苯基]甲烷、雙[3-(4-氨基苯氧基)苯基]甲烷、雙[4-(3-氨基苯氧基)苯基]甲烷、雙[4-(4-氨基苯氧基)苯基]甲烷、2,2-雙[3-(3-氨基苯氧基)苯基]丙烷、2,2-雙[3-(4-氨基苯氧基)苯基]丙烷、2,2-雙[4-(3-氨基苯氧基)苯基]丙烷、2,2-雙[4-(4-氨基苯氧基)苯基]丙烷(BAPP)、2,2-雙[3-(3-氨基苯氧基)苯基]-1,1,1,3,3,3-六氟丙烷，2,2-雙[3-(4-氨基苯氧基)苯基]-1,1,1,3,3,3-六氟丙烷、2,2-雙[4-(3-氨基苯氧基)苯基]-1,1,1,3,3,3-六氟丙烷或2,2-雙[4-(4-氨基苯氧基)苯基]-1,1,1,3,3,3-六氟丙烷等的在結構中具有四個苯核的二胺。
在一個示例中，根據本發明的二胺單體可以包括選自由1,4-二氨基苯(PPD)、1,3-二氨基苯(MPD)、2,4-二氨基甲苯、2,6-二氨基甲苯、4,4'-二氨基二苯醚(ODA)、4,4'-亞甲基二胺(MDA)、4,4-二氨基苯醯替苯胺(4,4-DABA)、N,N-雙(4-氨基苯基)苯-1,4-二甲醯胺(BPTPA)、2,2-二甲基聯苯胺(M-TOLIDINE)、2,2-雙(三氟甲基)聯苯胺(TFDB)、1,4-雙氨基苯氧基苯(TPE-Q)、雙氨基苯氧基苯(TPE-R)、2,2-雙氨基苯氧基苯基丙烷(BAPP)及2,2-雙氨基苯氧基苯基六氟丙烷(HFBAPP)組成的組中的至少一種。
根據本發明的聚醯胺酸組合物包括溶劑，上述溶劑可以是有機溶劑。與上述聚醯亞胺前體相容性好的溶劑可以為選自由N,N-二乙基乙醯胺(DEAC)、N,N-二甲基丙醯胺(DMPA)、3-甲氧基-N,N-二甲基丙醯胺(KJCMPA)、N-甲基-2吡咯烷酮(NMP)、γ-丁內酯(GBL)及二甘醇二甲醚(Diglyme)組成的組中的至少一種。
具體而言，從根據本發明的共軛導電高分子的分散性的觀點來看，優選為選自由N,N-二乙基乙醯胺(DEAC)、N,N-二甲基丙醯胺(DMPA)及N-甲基-2吡咯烷酮(NMP)組成的組中的至少一種。N,N-二乙基乙醯胺(DEAC)或N,N-二甲基丙醯胺(DMPA)極性較弱，因此，當單獨使用這些中的任何一種或增加其混合量時，可以提高共軛導電高分子的分散性。尤其，當混合具有環的N-甲基-2吡咯烷酮(NMP)和極性相對較弱的N,N-二乙基乙醯胺(DEAC)或N,N-二甲基丙醯胺(DMPA)時，共軛導電高分子的分散性得到提高，從而可以提高導電性和透明度。此時，相對於總溶劑的N-甲基-2吡咯烷酮(NMP)和N,N-二乙基乙醯胺(DEAC)或N,N-二甲基丙醯胺(DMPA)的摩爾比可以為3:7至7:3，例如，上述N-甲基-2吡咯烷酮(NMP)和N,N-二乙基乙醯胺(DEAC)或N,N-二甲基丙醯胺(DMPA)的摩爾比可以為6:4至4:6或4.5:5.5至5.5:4.5。
另外，本發明的聚醯胺酸組合物的溶劑的沸點可以為150℃以上。例如，聚醯胺酸組合物的溶劑的沸點可以為160℃以上或170℃以上。具體而言，上述溶劑的沸點的下限例如可以為155℃、160℃、165℃、170℃、175℃、180℃、185℃、190℃、195℃、200℃或201℃以上，上限例如可以為500℃、450℃、300℃、280℃、270℃、250℃、240℃、230℃、220℃、210℃或205℃以下。通過具有如上所述的沸點，在固化時可以容易地分離水和溶劑。
另一方面，為了提高滑動性、導熱性、導電性、耐電暈性、環硬度等薄膜的各種特性，本發明的聚醯胺酸組合物可以包括填料。添加的填料不受特別限制，例如可以舉出二氧化硅、氧化鈦、氧化鋁、氮化硅、氮化硼、磷酸氫鈣、磷酸鈣、雲母等。
上述填料的粒徑不受特別限制，可以取決於被改性膜的特性和添加的填料的種類。上述平均粒徑可為0.05μm至20μm、0.1μm至10μm、0.1μm至5μm或0.1μm至3μm。在本說明書中，除非另有說明，平均粒徑可以是根據D50粒度分析測定的平均粒徑。在本發明中，通過調節上述粒徑範圍，可以充分地保持改性效果，而不損害表面特性且不降低機械特性。
另外，在本發明中填料的添加量也不受特別限制，可以取決於被改性的膜特性、填料粒徑等。在本發明中，基於100重量份的組合物，上述填料的添加量可以為0.01重量份至10重量份、0.01重量份至5重量份或0.02重量份至1重量份。在本發明中，通過調節上述含量，可以充分地保持改性效果，而不降低薄膜的機械特性。添加上述填料的方法不受特別限制，而可以使用本領域公知的方法。
根據本發明的聚醯胺酸組合物的固含量可以為5重量%至30重量%。上述固含量可以為7重量%以上、9重量%以上、10重量%以上、13重量%以上、15重量%以上、17重量%以上，上限例如可以為30重量%以下、26重量%以下、24重量%以下、20重量%以下或19重量%以下。本發明通過將上述聚醯胺酸組合物的固含量調節在較高水平，在將固化後的物理性能保持在期望水平的同時控制黏度增加，並防止在固化過程中去除大量溶劑所需的製造成本和工藝時間的增加。
此外，本發明提供一種聚醯胺酸組合物的製備方法。根據本發明的聚醯胺酸組合物的製備方法包括聚合二酐單體和二胺單體的步驟。
作為上述二酐單體和二胺單體的聚合方法，可以使用溶液聚合等現有的聚醯亞胺前體聚合方法。
例如，上述方法的實例包括：(1)將二胺單體的全部量放入溶劑中，然後以與二胺單體實質上等摩爾地添加二酐單體進行聚合的方法；
(2)將二酐單體的全部量放入溶劑中，然後以與二酐單體大致等摩爾的比例添加二胺單體進行聚合的方法；
(3)將二胺單體中的一部分成分放入溶劑中後，相對於反應成分混合二酐單體的一部分成分，然後添加剩餘的二胺單體成分，並連續添加剩餘的二酐單體成分，使二胺單體和二酐單體實質上等摩爾的聚合方法；
(4)將二酐單體放入溶劑中後，相對於反應成分混合二胺單體的一部分成分，然後添加其他二酐單體成分，並連續添加剩餘的二胺單體成分，使二胺單體和二酐單體實質上等摩爾的聚合方法等。
此外，根據本發明的聚醯胺酸組合物的製備方法可以包括如下步驟：將二胺單體與溶劑混合以製備混合物；在上述混合物中混合共軛導電高分子；及在上述混合物中混合二酐單體。
通過按上述順序混合二胺單體、共軛導電高分子和二酐單體，提高共軛導電高分子的分散性，從而提高所製備的聚醯胺酸組合物和固化其而得的聚醯亞胺的導電性和透明性。
此時，基於組合物的總重量，上述共軛導電高分子的含量可以為0.01重量%至1重量%。具體而言，上述共軛導電高分子的含量可以為0.05重量%至1重量%、0.05重量%至0.9重量%、0.1重量%至1重量%、0.1重量%至0.7重量%、0.2重量%至1重量%、0.2重量%至0.9重量%、0.2重量%至0.7重量%、0.3重量%至1重量%、0.3重量%至0.9重量%、0.3重量%至0.7重量%、0.4重量%至0.7重量%或0.4重量%至0.6重量%。當根據本發明的聚醯胺酸組合物以如上所述的含量包含共軛導電高分子時，具有優異的透明度和優異的導電性。
根據本發明的聚醯胺酸組合物在固化後的熱膨脹係數(CTE)可以為10ppm/℃以下。例如，上述CTE的上限可以為9ppm/℃、8ppm/℃、7ppm/℃、6ppm/℃、5ppm/℃或4ppm/℃以下，下限可以為0.1ppm/℃、1ppm/℃、2.0ppm/℃或3ppm/℃以上。在一個示例中，上述熱膨脹係數可以是在100℃至450℃下測定的。對於上述CTE，可以使用TA公司的熱機械分析儀(thermomechanical analyzer)Q400型號，將聚醯亞胺製成薄膜後，將其切成2mm寬度和10mm長度的尺寸，並在氮氣氣氛下施加0.05N的張力，以10℃/分鐘的速度將溫度從室溫升高到500℃，然後再次以10℃/分鐘的速度冷卻，同時可以測定在100℃至450℃區間的斜率。
在一個示例中，根據本發明的聚醯胺酸組合物在固化後的玻璃化轉變溫度可以為400℃以上，例如，上述玻璃化轉變溫度的下限可以為403℃以上、405℃以上、410℃以上、420℃以上、430℃以上、440℃以上或450℃以上。上限可以為600℃以下。對於通過固化聚醯胺酸組合物製備的聚醯亞胺，可以使用TMA以10℃/分鐘的條件測定上述玻璃化轉變溫度。
根據本發明的聚醯胺酸組合物在固化後的1重量%熱分解溫度可以為500℃以上。上述熱分解溫度可以使用TA公司的熱重分析(thermogravimetric analysis)Q50型號來測定。在一個實施方式中，將通過固化上述聚醯胺酸獲得的聚醯亞胺在氮氣氣氛中以10℃/分鐘的速度升溫至150℃，然後保持等溫30分鐘以去除水分。此後，可以以10℃/分鐘的速度將溫度升高至600℃以測定發生1%重量損失的溫度。例如，上述熱分解溫度的下限可以為505℃以上、510℃以上、520℃以上、530℃以上、540℃以上、550℃以上、560℃以上或570℃以上。例如，上限可以為800℃、750℃、700℃、650℃或630℃以下。
根據本發明的聚醯胺酸組合物在固化後的120Hz下的介電常數可以為3.8F/m以上。例如，聚醯胺酸組合物在固化後在120Hz下的介電常數可以為3.9F/m以上、4.0F/m以上、4.1F/m以上、4.2F/m以上或4.3F/m以上，上限可以為5.0以下。在本發明中通過具有上述範圍的介電常數，在電子器件或電子工業領域中使用聚醯胺酸組合物或由其製備的聚醯胺酸時，可以賦予足夠的抗靜電效果。
另外，上述聚醯胺酸組合物在固化後的伸長率(Elongation)可以為10%以上，例如，可以為11%以上、12%以上、15%以上、20%以上或25%以上。上限不受特別限制，但可以為40%以下。至於上述伸長率，可以在將聚醯胺酸組合物固化成聚醯亞胺薄膜並切割成10mm寬度和40mm長度的尺寸後，通過ASTM D-882方法使用Instron公司的Instron5564 UTM設備來測定伸長率。
另外，本發明的聚醯胺酸組合物在固化後的彈性模量可以為5.0GPa以上。上述彈性模量的下限例如可以為6.0GPa以上、7.0GPa以上、8.0GPa以上或9.0GPa以上。上限不受特別限制，可以為15GPa以下。
另外，本聚醯胺酸組合物在固化後的抗拉強度可以為180MPa以上。例如，上述抗拉強度的下限可以為190MPa以上、200MPa以上、300MPa以上、400MPa以上、410MPa以上、420MPa以上或440MPa以上，上限例如可以為550MPa以下或530MPa以下。至於上述彈性模量和抗拉強度，可以在將上述聚醯胺酸組合物固化成聚醯亞胺薄膜並切割成10mm寬度和40mm長度的尺寸後，通過ASTM D-882方法使用Instron公司的Instron5564 UTM設備來測定彈性模量和抗拉強度。此時，可以在50mm/分鐘的十字頭速度(Cross Head Speed)條件下進行測定。
上述聚醯胺酸組合物可以為具有低黏度特性的組合物。本發明的聚醯胺酸組合物在23℃溫度和1s
-1的剪切速度條件下測定的黏度可以為10,000cP以下、5,000cP以下、4,000cP以下、3,500cP以下、3,300cP以下、3,200cP以下或3,100cP以下。其下限不受特別限制，但可以為500cP以上或1,000cP以上。例如，上述黏度可以使用Haake公司的Rheostress 600型號進行測定，且可以在1/s的剪切速度、23℃的溫度及1mm的板間隙條件下進行測定。本發明可以通過調節上述黏度範圍來提供具有優異工藝性的前體組合物。
此外，本發明提供一種聚醯亞胺的製備方法，其包括在支撐體上形成根據上述聚醯胺酸組合物的製備方法製備的聚醯胺酸組合物的薄膜並進行乾燥，以製備凝膠，將上述凝膠固化的步驟。
具體而言，本發明的聚醯亞胺的製備方法可以包括在支持體上形成上述聚醯胺酸組合物的薄膜、乾燥該薄膜而製備薄膜狀凝膠、固化上述凝膠的步驟。
固化上述凝膠的步驟可以通過如下工藝執行，即，將形成在上述支撐體上的聚醯胺酸組合物在20℃至120℃的溫度下乾燥5分鐘至60分鐘以製備凝膠膜，將上述凝膠膜的溫度以1℃/分鐘至8℃/分鐘的速度升高至30℃至500℃，在450℃至500℃下熱處理5分鐘至60分鐘，以1℃/分鐘至8℃/分鐘的速度冷卻至20℃至120℃。
將上述凝膠膜固化的步驟可以在30℃至500℃下進行。例如，對上述凝膠膜進行固化的步驟可以在30℃至400℃、30℃至300℃、30℃至200℃、30℃至100℃、100℃至500℃、100℃至300℃、200℃至500℃或400℃至500℃下進行。
上述聚醯亞胺薄膜的厚度可以為5μm至20μm。例如，上述聚醯亞胺薄膜的厚度可以為5μm至18μm、6μm至16μm、7μm至14μm、8μm至12μm或9μm至11μm。
例如，上述支撐體可以是無機基板，無機基板的實例可以包括玻璃基板和金屬基板，但優選使用玻璃基板，作為上述玻璃基板可以使用鈉鈣玻璃、硼硅酸鹽玻璃、無鹼玻璃等，但不限於此。
由於根據本發明的聚醯亞胺具有優異的耐熱性、透明度和導電性，因此可以被廣泛用作需要上述特性且對靜電問題敏感的電子電氣設備、平板顯示行業、半導體、太陽能電池行業等的需要高耐熱性的高科技核心機械部件。具體而言，可有用地用於高K(High-K)晶體管、氧化物-TFT用聚醯亞胺基板、LTPS-TFT用聚醯亞胺基板。
對照先前技術之功效
根據本發明的聚醯胺酸組合物及由其製備的聚醯亞胺在具有高透明度的同時具有優異的導電性。尤其，根據本發明的聚醯胺酸組合物及由其製備的聚醯亞胺在具有如上所述的高透明度和導電性的同時，還保持聚醯亞胺特有的優異的熱特性和機械特性。
Problems to be Solved by the Invention An object of the present invention is to provide a polyamide acid composition and a polyimide film having high transparency and low surface resistance. Technical means to solve the problem Polyimide resin is prepared by curing imidization after preparing polyamic acid derivatives by polymerization of aromatic dianhydride and aromatic diamine or aromatic diisocyanate. Polyimides are based on a rigid aromatic backbone and therefore have excellent thermal stability. However, contrary to the high thermal stability brought about by the aromatic main chain, the transparency is greatly reduced, and therefore, its use in the field of electronic materials, especially in the field of display requiring high transparency is limited. In particular, studies have recently been made to impart conductivity to polyimide for use in the field of the electronics industry, but it has been difficult to improve the transparency of polyimide to which a conductive material has been added. According to the polyamic acid composition of the present invention, by including a polymer comprising a dianhydride monomer and a diamine monomer as a polymerized unit and a conjugated conductive polymer having excellent compatibility in the polyamic acid composition, it can be Provides polyimide with excellent conductivity while having high transmittance. In addition, in the polyamic acid composition according to the present invention, the effect of the interaction between the conjugated conductive polymer and the solvent is excellent, so the dispersibility of the conjugated conductive polymer is excellent, and the polyamic acid composition prepared by curing the conjugated conductive polymer Polyimide contains a small amount of conjugated conductive polymer and has excellent conductivity. In particular, the polyamic acid composition according to the present invention has high transparency and electrical conductivity as described above, and also maintains excellent thermal and mechanical characteristics specific to polyimide. The present invention relates to a polyamide acid composition. The aforementioned polyamic acid composition includes a polymer having polymer units derived from dianhydride monomers and diamine monomers and a conjugated conductive polymer. The aforementioned conjugated conductive polymers are collectively referred to as polymers having a structure in which atomic valence electrons form multiple bonds centering on a single bond. Specifically, the above-mentioned conjugated conductive polymer may be a polymer having a chemical structure in which double bonds and single bonds or triple bonds and single bonds are alternately connected. Examples of conjugated conductive polymers according to the present invention may include polyfluorene, polyphenylene, polypyrene, polyazulene, polynaphthalene, polyacetylene, poly Thiophene (polythiophene), poly (3,4-ethylenedioxythiophene) (PEDOT), poly (p-phenylene sulfide) (poly (p-phenylene sulfide), polypyrrole (polypyrrole), polycarbazole (polycarbazole), poly Indole (polyindole), polyazepine (polyazepine) or polyaniline (polyaniline).When constituting the dianhydride monomer and the diamine monomer of the polymerization unit of the polymer according to the polyamic acid composition of the present invention include aromatic When using an aromatic dianhydride monomer and/or an aromatic diamine monomer, the conjugated conductive polymer may include aromatic rings or heteroatoms from the viewpoint of compatibility. Examples of the above-mentioned conjugated conductive polymer include those selected from free polymers Thiophene (polythiophene), poly (3,4-ethylenedioxythiophene) (PEDOT), poly (p-phenylene sulfide) (poly (p-phenylene sulfide), polypyrrole (polypyrrole), polycarbazole (polycarbazole), poly At least one of the group consisting of indole (polyindole), polyazepine (polyazepine) and polyaniline (polyaniline).In addition, the polyamic acid composition according to the present invention includes dianhydride monomers and diamine monomers The polymer of the present invention includes nitrogen atoms, so from the viewpoint of dispersibility and compatibility, the heteroatoms of the above-mentioned conjugated conductive macromolecules are preferably nitrogen, therefore, the conjugated conductive macromolecules according to the present invention can be selected from polypyrrole ( polypyrrole), polycarbazole (polycarbazole), polyindole (polyindole), polyazepine (polyazepine) and polyaniline (polyaniline). From the viewpoint of transparency, the low molecular weight polypyrrole containing nitrogen atom in the aromatic ring is preferred.The film conductivity (dry cast film conductivity, Dried Cast Film Conductivity) according to the conjugated conductive polymer of the present invention can be 0.005 S/cm or more. For example, the film conductivity of the above-mentioned conjugated conductive polymer can be 0.006 S/cm or more, 0.007 S/cm or more, 0.008 S/cm or more, 0.009 S/cm or more, or 0.01 S/cm or more When the membrane conductivity of the conjugated conductive polymer satisfies the membrane conductivity as described above, the polyamic acid composition including the above-mentioned conjugated conductive polymer may have improved electrical conductivity. At this time, based on the total weight of the polyamic acid composition, the content of the above-mentioned conjugated conductive polymer may be 0.01 wt % to 1 wt %. Specifically, the content of the above-mentioned conjugated conductive polymer can be 0.05% to 1% by weight, 0.05% to 0.9% by weight, 0.1% to 1% by weight, 0.1% to 0.7% by weight, 0.2% to 0.2% by weight. 1 wt%, 0.2 wt% to 0.9 wt%, 0.2 wt% to 0.7 wt%, 0.3 wt% to 1 wt%, 0.3 wt% to 0.9 wt%, 0.3 wt% to 0.7 wt%, 0.4 wt% to 0.7 wt% % or 0.4% to 0.6% by weight. When the polyamic acid composition according to the present invention contains the conjugated conductive polymer in the content as described above, it has excellent transparency and excellent conductivity. The surface resistance of the polyamic acid composition according to the present invention measured according to ASTM D257 after curing may be less than 1.0×10 13 Ω/□. In addition, the polyamic acid composition according to the present invention may have an average light transmittance of 10 μm thickness at a wavelength of 380 nm to 780 nm after being cured to be 50% or more. Specific measurement methods and measurement conditions for various physical properties described in the present invention are described in detail in Experimental Examples to be described below. Specifically, the polyamic acid composition according to the present invention may have an average light transmittance of 10 μm thickness at a wavelength of 380 nm to 780 nm after being cured to be 50% or more. For example, the above light transmittance can be above 52%, above 54%, above 56%, above 58%, above 60%, above 62%, above 64%, above 66%, above 68%, above 70%, or above 75%. More than, 80% or more, 82% or more, 84% or more, or 85% or more, the upper limit is not particularly limited, and may be 90% or less. The above light transmittance can be measured using a UV-Vis Spectrophotometer. In addition, the surface resistance of the polyamic acid composition according to the present invention measured according to ASTM D257 may be 1.0×10 13 Ω/□ or less. For example, the surface resistance may be 6.0×10 12 Ω/□ or less, 2.0×10 12 Ω/□ or less, 5.0×10 11 Ω/□ or less, or 2.0×10 11 Ω/□ or less. Can be 1.0×10 11 to 1.0×10 13 Ω/□, 1.0×10 11 to 6.0×10 12 Ω/□, 1.0×10 11 to 2.0×10 12 Ω/□, or 1.0×10 11 to 1.0×10 12 Ω/□. The present invention can provide a polyamic acid composition having high transparency and excellent conductivity by simultaneously satisfying the light transmittance and surface resistance as described above. The dianhydride monomer that can be used to prepare polyamic acid solution can be aromatic tetracarboxylic dianhydride, and the example of above-mentioned aromatic tetracarboxylic dianhydride can include pyromellitic dianhydride (or PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (or BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxygen diphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3',4'-tetracarboxylic dianhydride (or DSDA), bis(3,4-dicarboxyphenyl)sulfide dianhydride, 2,2-bis(3 ,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 3,3 ',4,4'-benzophenone tetracarboxylic dianhydride (or BTDA), bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl ) propane dianhydride, p-phenylene bis(trimellitic monoester anhydride), p-bisphenylene bis(trimellitic monoester anhydride), m-terphenyl-3,4,3',4'-tetraphenylene Carboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis (3,4-dicarboxyphenoxy)phthalic anhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyldianhydride, 2,2-bis[(3,4-dicarboxybenzene oxy)phenyl]propane dianhydride (BPADA), 2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride or 4,4'-(2,2 - Hexafluoroisopropylidene) diphthalic dianhydride and the like. The above-mentioned dianhydride monomers may be used alone or in combination of two or more as required, for example, may include pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) , oxydiphthalic dianhydride (ODPA), 4,4-(hexafluoroisopropylidene) diphthalic anhydride (6-FDA) and terephenylene bis(trimellitic anhydride) (TAHQ) at least one. In one embodiment of the present invention, the above-mentioned dianhydride monomer may include a dianhydride monomer having one benzene ring and a dianhydride monomer having two or more benzene rings. The above-mentioned dianhydride monomers having one benzene ring and the above-mentioned dianhydride monomers having two or more benzene rings can be used at 20 mol % to 60 mol % and 40 mol % to 90 mol %; 25 mol % to 55 mol %, respectively. mol % and 45 mol % to 80 mol %; or 35 mol % to 53 mol % and a molar ratio of 48 mol % to 75 mol % is comprised. In the present invention, by containing the above-mentioned dianhydride monomer, it is possible to achieve a desired level of mechanical performance while having excellent adhesive force. In addition, the diamine monomers that can be used to prepare the polyamic acid solution are aromatic diamines, which can be classified and illustrated as follows. 1) As such as 1,4-diaminobenzene (or p-phenylenediamine, PDA), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene or 3,5-diaminotoluene Diamines with a benzene nucleus in the structure such as aminobenzoic acid (or DABA), diamines with a relatively rigid structure; 2) such as 4,4'-diaminodiphenylmethane (methylenediamine), 3,3'-Dimethyl-4,4'-diaminobiphenyl, 2,2'-Dimethyl-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane, 3,3',5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis(4-aminophenyl)sulfide, 4,4'-diaminobenzamide, 3, 3'-dichlorobenzidine, 3,3'-dimethylbenzidine (or o-benzidine), 2,2'-dimethylbenzidine (or m-toluidine), 3,3'-dimethoxy benzidine, 2,2'-dimethoxybenzidine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (or Oxydianiline, ODA), 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diamino Diphenylphenone, 3,4'-diaminodiphenylphenone, 4,4'-diaminodiphenylphenone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodi Benzene, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminobenzene base) propane, 2,2-bis(3-aminophenyl)-1,1,1,3,3, 3-hexafluoropropane, 2,2-bis(4-aminophenyl)-1,1, In the Diamines with two benzene nuclei in the structure; 3) Such as 1,3-bis(3-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(3- Aminophenyl)benzene, 1,4-bis(4-amino)phenyl)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(3-aminophenoxy)benzene (or TPE-Q), 1,4-bis(4-aminophenoxy)benzene (or TPE-Q), 1,3-bis(3-aminophenoxy)-4-trifluoromethylbenzene, 3,3'-diamino-4-(4-phenyl)phenoxybenzophenone, 3,3'-diamino-4,4'-bis(4-phenylphenoxy)benzophenone Ketone, 1,3-bis(3-aminophenylsulfide)benzene, 1,3-bis(4-aminophenylsulfide)benzene, 1,4-bis(4-aminophenylsulfide)benzene, 1,3 -Bis(3-aminophenylene)benzene, 1,3-bis(4-aminophenylene)benzene, 1,4-bis(4-aminophenylene)benzene, 1,3-bis[2-(4- Aminophenyl)isopropyl]benzene, 1,4-bis[2-(3-aminophenyl)isopropyl]benzene or 1,4-bis[2-(4-aminophenyl)isopropyl] Benzene and other diamines with three benzene nuclei in the structure; 4) such as 3,3'-bis(3-aminophenoxy)biphenyl, 3,3'-bis(4-aminophenoxy)biphenyl Benzene, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, bis[3-(3-aminophenoxy)phenyl ]ether, bis[3-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl base] ether, bis[3-(3-aminophenoxy)phenyl]ketone, bis[3-(4-aminophenoxy)cy)phenyl]ketone, bis[4-(3-aminophenoxy Base) phenyl] ketone, bis [4-(4-aminophenoxy) phenyl] ketone, bis [3-(3-aminophenoxy) phenyl] sulfide, bis [3-(4-amino Phenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[3- (3-aminophenoxy)phenyl]pyridine, bis[3-(4-aminophenoxy)phenyl]pyridine, bis[4-(3-aminophenoxy)phenyl]pyridine, bis[4 -(4-aminophenoxy)cy)phenyl]pyridine, bis[3-(3-aminophenoxy)phenyl]methane, bis[3-(4-aminophenoxy)phenyl]methane, Bis[4-(3-aminophenoxy)phenyl]methane, bis[4-(4-aminophenoxy)phenyl]methane, 2,2-bis[3-(3-aminophenoxy) Phenyl]propane, 2,2-bis[3-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2 -Bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3 ,3-Hexafluoropropane, 2,2-bis[3-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4 -(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane or 2,2-bis[4-(4-aminophenoxy)phenyl]-1 , 1,1,3,3,3-hexafluoropropane and other diamines having four benzene nuclei in the structure. In one example, the diamine monomer according to the present invention may include 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6 -Diaminotoluene, 4,4'-diaminodiphenyl ether (ODA), 4,4'-methylenediamine (MDA), 4,4-diaminobenzoylaniline (4,4-DABA) , N,N-bis(4-aminophenyl)benzene-1,4-dimethylamide (BPTPA), 2,2-dimethylbenzidine (M-TOLIDINE), 2,2-bis(trifluoro Methyl)benzidine (TFDB), 1,4-bisaminophenoxybenzene (TPE-Q), bisaminophenoxybenzene (TPE-R), 2,2-bisaminophenoxyphenylpropane ( BAPP) and at least one of the group consisting of 2,2-bisaminophenoxyphenyl hexafluoropropane (HFBAPP). The polyamic acid composition according to the present invention includes a solvent, and the solvent may be an organic solvent. The solvent with good compatibility with the above-mentioned polyimide precursor can be selected from N,N-diethylacetamide (DEAC), N,N-dimethylacrylamide (DMPA), 3-methoxy In the group consisting of N,N-dimethylacrylamide (KJCMPA), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL) and diglyme (Diglyme) at least one. Specifically, from the viewpoint of the dispersibility of the conjugated conductive polymer according to the present invention, it is preferably selected from N,N-diethylacetamide (DEAC), N,N-dimethylacrylamide (DMPA) and at least one of the group consisting of N-methyl-2-pyrrolidone (NMP). N,N-diethylacetamide (DEAC) or N,N-dimethylacrylamide (DMPA) are less polar, so when either of these is used alone or in increasing amounts in combination, it can increase Dispersion of Conjugated Conductive Polymers. Especially, when mixing N-methyl-2-pyrrolidone (NMP) with a ring and relatively weak polarity N,N-diethylacetamide (DEAC) or N,N-dimethylacrylamide (DMPA) When , the dispersibility of the conjugated conductive polymer is improved, so that the conductivity and transparency can be improved. At this time, the molar ratio of N-methyl-2-pyrrolidone (NMP) and N,N-diethylacetamide (DEAC) or N,N-dimethylacrylamide (DMPA) relative to the total solvent can be 3:7 to 7:3, e.g., the aforementioned N-methyl-2-pyrrolidone (NMP) and N,N-diethylacetamide (DEAC) or N,N-dimethylacrylamide (DMPA) The molar ratio of may be from 6:4 to 4:6 or from 4.5:5.5 to 5.5:4.5. In addition, the boiling point of the solvent of the polyamic acid composition of this invention may be 150 degreeC or more. For example, the boiling point of the solvent of the polyamic acid composition may be 160°C or higher or 170°C or higher. Specifically, the lower limit of the boiling point of the above-mentioned solvent can be, for example, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C or 201°C, and the upper limit can be, for example, 500°C, 450°C, 300°C, 280°C, 270°C, 250°C, 240°C, 230°C, 220°C, 210°C or 205°C or less. By having a boiling point as described above, water and a solvent can be easily separated at the time of solidification. On the other hand, the polyamic acid composition of the present invention may contain fillers in order to improve various properties of the film such as slidability, thermal conductivity, electrical conductivity, corona resistance, and ring hardness. The filler to be added is not particularly limited, and examples thereof include silicon dioxide, titanium oxide, aluminum oxide, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica, and the like. The particle size of the above-mentioned fillers is not particularly limited, and may depend on the properties of the membrane to be modified and the type of fillers added. The above average particle size may be 0.05 μm to 20 μm, 0.1 μm to 10 μm, 0.1 μm to 5 μm, or 0.1 μm to 3 μm. In this specification, unless otherwise stated, the average particle diameter may be the average particle diameter measured according to D50 particle size analysis. In the present invention, by adjusting the above particle size range, the modification effect can be sufficiently maintained without impairing the surface properties and without reducing the mechanical properties. In addition, the amount of filler added in the present invention is not particularly limited, and may depend on the properties of the membrane to be modified, the particle size of the filler, and the like. In the present invention, based on 100 parts by weight of the composition, the amount of the above-mentioned fillers may be 0.01 to 10 parts by weight, 0.01 to 5 parts by weight or 0.02 to 1 part by weight. In the present invention, by adjusting the above content, the modifying effect can be sufficiently maintained without reducing the mechanical properties of the film. The method of adding the above-mentioned filler is not particularly limited, and a method known in the art may be used. The solid content of the polyamic acid composition according to the present invention may be 5% by weight to 30% by weight. The above-mentioned solid content can be 7% by weight or more, 9% by weight or more, 10% by weight or more, 13% by weight or more, 15% by weight or more, or 17% by weight or more. The upper limit can be, for example, 30% by weight or less, 26% by weight or less, 24% by weight or less. % by weight or less, 20% by weight or less, or 19% by weight or less. The present invention controls the viscosity increase while maintaining the physical properties after curing at the desired level by adjusting the solid content of the above-mentioned polyamic acid composition at a higher level, and prevents the manufacturing process required to remove a large amount of solvent during the curing process. Increased cost and process time. In addition, the present invention provides a preparation method of the polyamic acid composition. The preparation method of the polyamic acid composition according to the present invention includes the steps of polymerizing dianhydride monomers and diamine monomers. As the polymerization method of the above-mentioned dianhydride monomer and diamine monomer, a conventional polyimide precursor polymerization method such as solution polymerization can be used. For example, examples of the above methods include: (1) a method in which the entire amount of the diamine monomer is put into a solvent, and then the dianhydride monomer is added substantially equimolarly with the diamine monomer to carry out polymerization; (2) Put the whole amount of the dianhydride monomer into the solvent, and then add the diamine monomer in a roughly equimolar ratio to the dianhydride monomer to polymerize; (3) put a part of the diamine monomer into the solvent Finally, mix a part of the dianhydride monomer with respect to the reaction component, then add the remaining diamine monomer component, and continuously add the remaining dianhydride monomer component so that the diamine monomer and the dianhydride monomer are substantially equimolar (4) After putting the dianhydride monomer into the solvent, mix a part of the diamine monomer with respect to the reaction components, then add other dianhydride monomer components, and continuously add the remaining diamine monomer components , a polymerization method in which a diamine monomer and a dianhydride monomer are substantially equimolar, and the like. In addition, the preparation method of the polyamic acid composition according to the present invention may include the following steps: mixing a diamine monomer with a solvent to prepare a mixture; mixing a conjugated conductive polymer in the above mixture; and mixing two diamine monomers in the above mixture. anhydride monomer. By mixing the diamine monomer, the conjugated conductive polymer and the dianhydride monomer in the above order, the dispersibility of the conjugated conductive polymer is improved, thereby improving the prepared polyamic acid composition and the polyamide obtained by curing it. Conductivity and transparency of imines. At this time, based on the total weight of the composition, the content of the above-mentioned conjugated conductive polymer may be 0.01% by weight to 1% by weight. Specifically, the content of the above-mentioned conjugated conductive polymer can be 0.05% to 1% by weight, 0.05% to 0.9% by weight, 0.1% to 1% by weight, 0.1% to 0.7% by weight, 0.2% to 0.2% by weight. 1 wt%, 0.2 wt% to 0.9 wt%, 0.2 wt% to 0.7 wt%, 0.3 wt% to 1 wt%, 0.3 wt% to 0.9 wt%, 0.3 wt% to 0.7 wt%, 0.4 wt% to 0.7 wt% % or 0.4% to 0.6% by weight. When the polyamic acid composition according to the present invention contains the conjugated conductive polymer in the content as described above, it has excellent transparency and excellent conductivity. The polyamic acid composition according to the present invention may have a coefficient of thermal expansion (CTE) of 10 ppm/° C. or less after curing. For example, the upper limit of the above CTE can be 9ppm/°C, 8ppm/°C, 7ppm/°C, 6ppm/°C, 5ppm/°C or 4ppm/°C, and the lower limit can be 0.1ppm/°C, 1ppm/°C, 2.0ppm/°C or Above 3ppm/℃. In one example, the above coefficient of thermal expansion may be measured at 100°C to 450°C. For the above CTE, you can use TA's thermomechanical analyzer (thermomechanical analyzer) Q400 model, after polyimide is made into a film, cut it into a size of 2mm width and 10mm length, and apply 0.05N under nitrogen atmosphere The tension is raised from room temperature to 500°C at a rate of 10°C/min, and then cooled again at a rate of 10°C/min, and the slope in the range of 100°C to 450°C can be measured at the same time. In one example, the glass transition temperature of the polyamic acid composition according to the present invention after curing may be above 400°C. For example, the lower limit of the above glass transition temperature may be above 403°C, above 405°C, or above 410°C. above, above 420°C, above 430°C, above 440°C or above 450°C. The upper limit may be 600°C or less. For a polyimide prepared by curing a polyamic acid composition, the above-mentioned glass transition temperature can be measured using TMA at a condition of 10° C./min. The 1% by weight thermal decomposition temperature of the polyamic acid composition according to the present invention after curing may be 500° C. or higher. The above-mentioned thermal decomposition temperature can be measured using a thermogravimetric analysis (thermogravimetric analysis) Q50 model of TA Company. In one embodiment, the temperature of the polyimide obtained by curing the above polyamic acid is raised to 150° C. at a rate of 10° C./min in a nitrogen atmosphere, and then kept isothermally for 30 minutes to remove moisture. Thereafter, the temperature may be raised to 600°C at a rate of 10°C/minute to measure the temperature at which 1% weight loss occurs. For example, the lower limit of the thermal decomposition temperature may be 505°C or higher, 510°C or higher, 520°C or higher, 530°C or higher, 540°C or higher, 550°C or higher, 560°C or higher, or 570°C or higher. For example, the upper limit may be 800°C, 750°C, 700°C, 650°C, or 630°C or less. The polyamic acid composition according to the present invention may have a dielectric constant of 3.8 F/m or more at 120 Hz after curing. For example, the dielectric constant of the polyamic acid composition at 120 Hz after curing may be more than 3.9 F/m, more than 4.0 F/m, more than 4.1 F/m, more than 4.2 F/m or more than 4.3 F/m, The upper limit may be 5.0 or less. In the present invention, by having a dielectric constant within the above range, a sufficient antistatic effect can be imparted when the polyamic acid composition or the polyamic acid prepared therefrom is used in the field of electronic devices or electronics industry. In addition, the elongation of the polyamic acid composition after curing may be 10% or more, for example, 11% or more, 12% or more, 15% or more, 20% or more or 25% or more. The upper limit is not particularly limited, but may be 40% or less. As for the elongation mentioned above, the elongation can be measured by ASTM D-882 method using Instron 5564 UTM equipment of Instron Corporation after curing the polyamic acid composition into a polyimide film and cutting into dimensions of 10 mm width and 40 mm length . In addition, the elastic modulus after curing of the polyamic acid composition of the present invention may be 5.0 GPa or more. The lower limit of the elastic modulus may be, for example, 6.0 GPa or more, 7.0 GPa or more, 8.0 GPa or more, or 9.0 GPa or more. The upper limit is not particularly limited, and may be 15 GPa or less. In addition, the tensile strength of the polyamic acid composition after curing may be 180 MPa or more. For example, the lower limit of the tensile strength may be 190 MPa or more, 200 MPa or more, 300 MPa or more, 400 MPa or more, 410 MPa or more, 420 MPa or more, or 440 MPa or more, and the upper limit may be, for example, 550 MPa or less or 530 MPa or less. As for the above-mentioned modulus of elasticity and tensile strength, Instron 5564 of Instron Corporation can be used by the method of ASTM D-882 after curing the above-mentioned polyamic acid composition into a polyimide film and cutting it into a size of 10mm width and 40mm length. UTM equipment to determine elastic modulus and tensile strength. In this case, the measurement can be performed under the condition of a cross head speed (Cross Head Speed) of 50 mm/min. The above-mentioned polyamic acid composition may be a composition having low viscosity properties. The viscosity of the polyamic acid composition of the present invention measured under the conditions of a temperature of 23°C and a shear rate of 1 s -1 may be 10,000 cP or less, 5,000 cP or less, 4,000 cP or less, 3,500 cP or less, 3,300 cP or less, or 3,200 cP Below or below 3,100cP. The lower limit thereof is not particularly limited, but may be 500 cP or more or 1,000 cP or more. For example, the above-mentioned viscosity can be measured using a Rheostress 600 model of Haake Corporation, and can be measured under the conditions of a shear rate of 1/s, a temperature of 23° C., and a plate gap of 1 mm. The present invention can provide a precursor composition with excellent manufacturability by adjusting the above viscosity range. In addition, the present invention provides a method for preparing polyimide, which includes forming a film of the polyamic acid composition prepared according to the above method for preparing the polyamic acid composition on a support and drying it to prepare a gel , the step of solidifying the above-mentioned gel. Specifically, the method for producing polyimide of the present invention may include the steps of forming a film of the above-mentioned polyamic acid composition on a support, drying the film to prepare a film-like gel, and curing the above-mentioned gel. The step of curing the above-mentioned gel may be performed by the following process, that is, drying the polyamic acid composition formed on the above-mentioned support at a temperature of 20° C. to 120° C. for 5 minutes to 60 minutes to prepare a gel film, and The temperature of the above-mentioned gel film is raised to 30°C to 500°C at a rate of 1°C/min to 8°C/min, heat-treated at 450°C to 500°C for 5 minutes to 60 minutes, and at a rate of 1°C/min to 8°C/min Minute speed cooling to 20°C to 120°C. The step of curing the above gel film may be performed at 30°C to 500°C. For example, the step of curing the above-mentioned gel film can be carried out at 30°C to 400°C, 30°C to 300°C, 30°C to 200°C, 30°C to 100°C, 100°C to 500°C, 100°C to 300°C, 200°C °C to 500°C or 400°C to 500°C. The above polyimide film may have a thickness of 5 μm to 20 μm. For example, the polyimide film may have a thickness of 5 μm to 18 μm, 6 μm to 16 μm, 7 μm to 14 μm, 8 μm to 12 μm, or 9 μm to 11 μm. For example, the above-mentioned support body may be an inorganic substrate. Examples of the inorganic substrate may include a glass substrate and a metal substrate, but a glass substrate is preferably used. As the above-mentioned glass substrate, soda-lime glass, borosilicate glass, alkali-free glass, etc. may be used, but Not limited to this. Since the polyimide according to the present invention has excellent heat resistance, transparency and electrical conductivity, it can be widely used as a material for electronic and electrical equipment, flat panel display industry, semiconductor, solar cell industry, etc., which require the above characteristics and are sensitive to static electricity problems. High-tech core mechanical components that require high heat resistance. Specifically, it can be usefully used for high-K (High-K) transistors, polyimide substrates for oxide-TFTs, and polyimide substrates for LTPS-TFTs. Efficacy compared to the prior art The polyamic acid composition according to the present invention and the polyimide prepared therefrom have excellent electrical conductivity while having high transparency. In particular, the polyamic acid composition according to the present invention and the polyimide prepared therefrom maintain the excellent thermal and mechanical properties specific to polyimide while having high transparency and electrical conductivity as described above .
