TWI735550B - Polyamide acid, polyamide acid solution, polyimide, and polyimide substrate and manufacturing method thereof - Google Patents

Abstract

The polyamide acid of the present invention contains a structural unit represented by the general formula 1 and a structural unit represented by the general formula 2. A of the general formula 1 and B of the general formula 2 are each independently a tetravalent aromatic group; R ¹ and R ^{2 of the} general formula 2 are each independently a divalent hydrocarbon group; n is an integer of 1-5. Polyimide can be obtained by imidizing polyamide acid. A polyimide substrate can be obtained by imidizing a polyimide solution containing polyimide and organic polyimide on a support such as glass.

Description

Polyamide acid, polyamide acid solution, polyimide, and polyimide substrate and manufacturing method thereof

The present invention relates to a polyimide, polyimide solution, polyimide, and polyimide substrate.

Electronic devices such as displays, touch panels, and solar cells are required to be thinner, lighter, and flexible, and research is underway to replace glass substrates with resin film substrates. In the manufacturing process of these electronic devices, electronic components such as thin-film transistors and other semiconductors or electrodes are formed on the substrate. Since the formation of these components requires a high-temperature process, the resin film substrate is required to have higher heat resistance. The components arranged on the substrate usually contain inorganic materials. If the linear thermal expansion coefficient of the substrate differs greatly from the linear thermal expansion coefficient of the inorganic material constituting the element, the substrate may be warped or the element may be destroyed due to the stress at the interface forming the element. Therefore, it is desirable that the resin film substrate has a linear thermal expansion coefficient equivalent to that of the inorganic material constituting the element. In liquid crystal displays or bottom-emission organic EL (Electroluminescence) devices, since the light from the display device is emitted through the substrate, the resin film substrate is required to be transparent, especially the visible light region has a higher light transmittance. . For the above reasons, high heat resistance, low thermal expansion, and high transparency are required for resin film substrate materials for electronic devices. The manufacturing process of electronic devices is divided into batch type and roll-to-roll type. The resin film substrate can also be applied to the roll-to-roll process, but the manufacture of electronic devices using the roll-to-roll process requires new equipment and must overcome the new problems associated with roller transport. On the other hand, in the batch process, as long as the resin solution is coated on the support and dried to form a film substrate, and elements are formed on it, the current process equipment for glass substrates can be used. There are advantages in cost. As a resin material that can achieve high heat resistance, low thermal expansion, and high transparency comparable to glass, polyimide-based materials with excellent heat resistance are being researched. It is known that a polyimide system using a rigid structure monomer or an alicyclic monomer has high transparency and low thermal expansion (Patent Document 1 and Patent Document 2). In addition, it is known that by adding polysiloxane oil to polyimide which is a precursor of polyimide, and performing imidization, the obtained polyimide film exhibits high adhesion to the substrate. (Patent Document 3). [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open No. 2012-041530 [Patent Document 2] Japanese Patent No. 5660249 [Patent Document 3] Japanese Patent Laid-Open No. 2015-229691

[化2]

本發明之聚醯亞胺含有通式I所表示之結構單元、及通式II所表示之結構單元。 [化3]

[化4]

通式1及通式I中之A、以及通式2及通式II中之B均為四價之芳香族基。於通式2及通式II中，R¹ 及R² 分別獨立地為二價之烴基，n為1～5之整數。 四價之芳香族基A及B均為芳香族四羧酸二酐之殘基，較佳為聯苯-3,3',4,4'-四基。R¹ 及R² 分別獨立地較佳為亞甲基、伸乙基或伸丙基，其中尤佳為伸丙基。n更佳為1～3，最佳為1。 即，本發明之聚醯胺酸較佳為含有下述式1A所表示之結構單元及下述式2C所表示之結構單元，本發明之聚醯亞胺較佳為含有下述式IA所表示之結構單元及下述式IIC所表示之結構單元。 [化5]

[化6]

[化7]

[化8]

本發明係關於一種含有上述聚醯亞胺之聚醯亞胺基板。例如藉由將含有上述聚醯胺酸及有機溶劑之聚醯胺酸溶液塗佈於支持體上，並進行有機溶劑之去除及聚醯胺酸之醯亞胺化，可獲得聚醯亞胺基板。該聚醯亞胺基板係作為密接積層於支持體上之聚醯亞胺膜而形成。作為塗佈聚醯胺酸溶液之支持體，例如使用玻璃。 [發明之效果] 由本發明之聚醯胺酸所獲得之聚醯亞胺除了高耐熱性、低熱膨脹性及高透明性以外，具有對玻璃等支持體之適度之密接性。因此，適合作為批次製程中要求對支持體之適度之密接性的電子器件用基板材料。[Problems to be Solved by the Invention] In order to apply polyimide substrates to batch processes, in addition to high heat resistance, low thermal expansion, and high transparency, glass is required to be displayed and used as a support in the device formation process Moderate adhesiveness, and can be easily peeled from the glass support after the device is formed. However, the polyimide materials disclosed in the above-mentioned Patent Documents 1 to 3 cannot satisfy all of these required characteristics at the same time. In view of the above, the object of the present invention is to provide a polyimide having high heat resistance, low thermal expansion and high transparency, and showing moderate adhesion with glass as a support, and a precursor thereof Polyamide acid. [Technical Means to Solve the Problem] The inventors of the present case discovered that by introducing rigid structures and alicyclic structures into the polymer backbone, and then using monomer components with siloxane bonds together, a polyamide that satisfies the above characteristics can be obtained. Amine, and polyamide acid as its precursor. The polyamide acid of the present invention contains a structural unit represented by the general formula 1 and a structural unit represented by the general formula 2. [化1]

[化2]

The polyimide of the present invention contains a structural unit represented by the general formula I and a structural unit represented by the general formula II. [化3]

[化4]

A in Formula 1 and Formula I, and B in Formula 2 and Formula II are all tetravalent aromatic groups. In Formula 2 and Formula II, R ¹ and R ² are each independently a divalent hydrocarbon group, and n is an integer of 1-5. The tetravalent aromatic groups A and B are both residues of aromatic tetracarboxylic dianhydrides, preferably biphenyl-3,3',4,4'-tetrayl. R ¹ and R ² are each independently preferably methylene, ethylene or propylene, and particularly preferably, propylene. n is more preferably 1-3, most preferably 1. That is, the polyimide of the present invention preferably contains the structural unit represented by the following formula 1A and the structural unit represented by the following formula 2C, and the polyimide of the present invention preferably contains the structural unit represented by the following formula IA The structural unit and the structural unit represented by the following formula IIC. [化5]

[化6]

[化7]

[化8]

The present invention relates to a polyimide substrate containing the above-mentioned polyimide. For example, a polyimide substrate can be obtained by coating a polyimide solution containing the above-mentioned polyimide acid and an organic solvent on the support, and then removing the organic solvent and imidizing the polyimide acid. . The polyimide substrate is formed as a polyimide film laminated on a support in close contact. As the support for coating the polyamide acid solution, for example, glass is used. [Effects of the invention] In addition to high heat resistance, low thermal expansion, and high transparency, the polyimide obtained from the polyamide acid of the present invention has moderate adhesion to supports such as glass. Therefore, it is suitable as a substrate material for electronic devices that requires proper adhesion to a support in a batch process.

[化10]

本發明之聚醯亞胺包含以下之通式I所表示之結構單元及通式II所表示之結構單元，例如可藉由將具有上述結構1及結構2之聚醯胺酸加以醯亞胺化而獲得。 [化11]

[化12]

上述通式1及上述通式I中之A、以及上述通式2及上述通式II中之B均為四價之芳香族基。芳香族基可具有單一之芳香族環，亦可為複數個芳香族環鍵結而成者，亦可為縮合多環。於上述通式2及上述通式II中，R¹ 及R² 分別獨立地為二價之烴基，n為1～5之整數。 藉由將含有上述通式1之結構單元及上述通式2之結構單元之聚醯胺酸加以醯亞胺化，可獲得含有通式I之結構單元及通式II之結構單元之聚醯亞胺。具有該結構之聚醯亞胺係與玻璃之密接性優異，故而適合用於批次製程中之樹脂膜基板之形成、及向膜基板上之元件之形成製程。 上述A及B較佳為芳香族四羧酸二酐之殘基。作為芳香族四羧酸二酐，可列舉：均苯四甲酸二酐、3,3',4,4-聯苯四羧酸二酐、3,3',4,4'-二苯甲酮四羧酸二酐、2,3,3',4'-聯苯四羧酸二酐、3,3',4,4'-二苯碸四羧酸二酐、1,4,5,8-萘四羧酸二酐、2,3,6,7-萘四羧酸二酐、1,2,5,6-萘四羧酸二酐、4,4'-氧二鄰苯二甲酸酐、9,9-雙(3,4-二羧基苯基)茀二酐、9,9'-雙[4-(3,4-二羧基苯氧基)苯基]茀二酐、3,3',4,4'-聯苯醚四羧酸二酐、2,3,5,6-吡啶四羧酸二酐、3,4,9,10-苝四羧酸二酐、4,4'-磺醯基二鄰苯二甲酸二酐、對聯三苯-3,4,3',4'-四羧酸二酐、間聯三苯-3,3',4,4'-四羧酸二酐、3,3',4,4'-二苯醚四羧酸二酐等，但並不限定於該等。通式1及通式I中之A、與通式2及通式II中之B可相同亦可不同。 就可獲得高透明性且低線膨脹係數之聚醯亞胺而言，A尤佳為3,3',4,4'-聯苯四羧酸二酐之殘基(下述化學式所表示之聯苯-3,3',4,4'-四基)。 [化13]

即，通式1之結構單元較佳為下述式1A所表示之醯胺酸結構單元，通式I之結構單元較佳為下述式IA所表示之醯亞胺結構單元。該等結構單元可由3,3',4,4'-聯苯四羧酸二酐與1,4-環己二胺而獲得。 [化14]

[化15]

就可獲得高透明性且低線膨脹係數之聚醯亞胺而言，B尤佳為3,3',4,4'-聯苯四羧酸二酐之殘基。即，通式2所表示之結構單元較佳為下述通式2A所表示之醯胺酸結構單元，通式II所表示之結構單元較佳為下述通式IIA所表示之醯亞胺結構單元。該等結構單元可由3,3',4,4'-聯苯四羧酸二酐與含矽氧烷結構之二胺而獲得。 [化16]

[化17]

如上所述，A與B亦可相同。就同時實現聚醯亞胺膜之高透明性與低線膨脹係數之觀點而言，A及B較佳為均為聯苯-3,3',4,4'-四基。 就聚醯胺酸之聚合時之反應性優異，且聚醯亞胺顯示出低熱膨脹性而言，上述通式2及上述通式II中之R¹ 及R² 分別獨立地較佳為亞甲基、伸乙基或伸丙基，其中尤佳為伸丙基。就聚醯胺酸顯示出較高之溶解性，且聚醯亞胺膜顯示出高透明性而言，上述通式2及上述通式II中之n較佳為1～5，更佳為1～3，最佳為1。 即，通式2之結構單元較佳為下述通式2B所表示之醯胺酸結構單元，通式II之結構單元較佳為下述通式IIB所表示之醯亞胺結構單元。該等結構單元可由芳香族四羧酸二酐與作為二胺成分之1,3-雙(3-胺基丙基)四甲基二矽氧烷而獲得。 [化18]

[化19]

如上所述，通式2及通式II中之四價之芳香族基B較佳為聯苯-3,3',4,4'-四基。因此，通式2之結構單元尤佳為下述式2C所表示之醯胺酸結構單元，通式II之結構單元尤佳為下述式IIC所表示之醯亞胺結構單元。該等結構單元可由3,3',4,4'-聯苯四羧酸二酐與1,3-雙(3-胺基丙基)四甲基二矽氧烷而獲得。 [化20]

[化21]

就使聚醯亞胺膜具有高耐熱性、低熱膨脹性、高透明性及與玻璃之適度之密接性之觀點而言，聚醯亞胺中之通式I所表示之結構單元與通式II所表示之結構單元之合計係相對於聚醯亞胺總量而較佳為80莫耳%以上，更佳為90莫耳%以上，尤佳為95莫耳%以上。為了將通式I所表示之結構單元與通式II所表示之結構單元之合計設為上述範圍，作為前驅物之聚醯胺酸中之通式1所表示之結構單元與通式2所表示之結構單元之合計係相對於聚醯胺酸總量而較佳為80莫耳%以上，更佳為90莫耳%以上，尤佳為95莫耳%以上。 所謂聚醯亞胺之莫耳數，係源自構成聚醯亞胺之所有二胺之結構單元之莫耳數。所謂聚醯胺酸之莫耳數，係源自構成聚醯胺酸之所有二胺之結構單元之莫耳數。由於聚醯亞胺及聚醯胺酸含有等莫耳之源自二胺之結構單元與源自酸二酐之結構單元，故而於聚醯亞胺及聚醯胺酸中，源自所有二胺之結構單元之莫耳數與源自所有酸二酐之結構單元之莫耳數相等。 就獲得除了高透明性及低熱膨脹性以外具有與支持體之適度之密接性的聚醯亞胺之觀點而言，聚醯亞胺中之通式I所表示之結構單元之莫耳數M_A 與通式II所表示之結構單元之莫耳數M_B 之比M_A /M_B 較佳為95.0/5.0～99.9/0.1之範圍。即，本發明之聚醯亞胺較佳為二胺成分之大部分為1,4-環己二胺，且包含少量之1,3-雙(3-胺基丙基)四甲基二矽氧烷等含矽氧烷結構之二胺。藉由在二胺成分中導入少量之矽氧烷結構，有聚醯亞胺對玻璃等支持體之密接性提高之傾向。因此，於在支持體上塗佈聚醯胺酸溶液並進行醯亞胺化時，可抑制聚醯亞胺與支持體之間之剝離或隆起。 伴隨著矽氧烷結構之含量之增大，有與玻璃等之密接性提高之傾向。另一方面，若密接性過高，則有自支持體剝離聚醯亞胺膜變得困難，於剝離時產生尺寸變化或不透明化之情況。若M_A /M_B 為95.0/5.0以上，則可無問題地實施於聚醯亞胺膜上形成電子元件等之後的自支持體之聚醯亞胺膜之剝離。又，若M_A /M_B 為95.0/5.0以上，則可維持聚醯亞胺膜之低熱膨脹特性及高透明性。 M_A /M_B 更佳為96.0/4.0～99.8/0.2，進而較佳為97.0/3.0～99.7/0.3，尤佳為98.0/2.0～99.6/0.4，最佳為99.0/1.0～99.5/0.5。 為了將聚醯亞胺中之通式I所表示之結構單元與通式II所表示之結構單元之比率設為上述範圍，作為前驅物之聚醯胺酸中的通式1所表示之結構單元之莫耳數m_A 與通式2所表示之結構單元之莫耳數m_B 之比m_A /m_B 較佳為95.0/5.0～99.9/0.1之範圍，更佳為96.0/4.0～99.8/0.2，進而較佳為97.0/3.0～99.7/0.3，尤佳為98.0/2.0～99.6/0.4，最佳為99.0/1.0～99.6/0.4。 本發明之聚醯胺酸及聚醯亞胺較佳為由凝膠滲透層析法(GPC，Gel Permeation Chromatography)所得之聚環氧乙烷換算之重量平均分子量為10,000～500,000，更佳為20,000～300,000，進而較佳為30,000～200,000。若重量平均分子量為10,000以上，則可將聚醯胺酸及聚醯亞胺製成塗膜或膜。另一方面，若重量平均分子量為500,000以下，則對溶劑顯示出充分之溶解性，因此容易獲得表面平滑且膜厚均勻之塗膜或膜。 [聚醯胺酸及聚醯亞胺之合成] 包含上述結構I及結構II之聚醯亞胺可藉由公知之方法獲得。聚醯亞胺可藉由經由聚醯胺酸或聚醯亞胺酯等前驅物之合成法、及不經由前驅物之合成法而合成。就單體之獲取性及聚合之簡便性而言，較佳為藉由作為前驅物之聚醯胺酸之醯亞胺化而合成聚醯亞胺。 包含上述結構1及結構2之聚醯胺酸可藉由使二胺與四羧酸二酐於有機溶劑中反應而獲得。例如只要使二胺溶解或漿料狀地分散於有機溶劑中，製成二胺溶液，並將四羧酸二酐以溶解或者漿料狀地分散於有機溶劑中而成之溶液或固體之狀態添加至上述二胺溶液中即可。亦可於四羧酸二酐溶液中添加二胺。二胺及四羧酸二酐之溶解及反應較佳為於氬氣、氮氣等惰性氣體環境中實施。 於聚醯胺酸之合成中，較佳為將二胺成分總量之莫耳數、與四羧酸二酐成分總量之莫耳數調整為實質上等莫耳。藉由使用複數種二胺及/或複數種四羧酸二酐，可獲得具有複數種結構之聚醯胺酸。又，亦可藉由摻合結構不同之聚醯胺酸，而獲得具有結構不同之複數種結構單元之聚醯胺酸。 藉由使用芳香族四羧酸二酐作為四羧酸二酐，且使用1,4-環己二胺及含矽氧烷結構之二胺作為二胺，可獲得含有通式1所表示之結構單元及通式2所表示之結構單元之聚醯胺酸。藉由使用3,3',4,4'-聯苯四羧酸二酐作為芳香族二胺，且使用1,3-雙(3-胺基丙基)四甲基二矽氧烷作為含矽氧烷結構之二胺，可獲得含有式1A所表示之醯胺酸結構單元及式1C所表示之醯胺酸結構單元之聚醯胺酸。藉由將1,4-環己二胺之莫耳數與含矽氧烷結構之二胺之莫耳數之比設為95.0/5.0～99.9/0.1之範圍，可獲得m_A /m_B 為95.0/5.0～99.9/0.1之範圍之聚醯胺酸。 用於聚醯胺酸之合成反應之有機溶劑並無特別限定。有機溶劑較佳為可溶解所使用之四羧酸二酐及二胺類，且可溶解藉由聚合而生成之聚醯胺酸。作為有機溶劑之具體例，可列舉：四甲基脲、N,N-二甲基乙基脲等脲系溶劑；二甲基亞碸、二苯碸、四甲基碸等亞碸或碸系溶劑；N,N-二甲基乙醯胺(DMAC)、N,N-二甲基甲醯胺(DMF)、N,N'-二乙基乙醯胺、N-甲基-2-吡咯啶酮(NMP)、γ-丁內酯等酯系溶劑；六甲基磷醯三胺等醯胺系溶劑；氯仿、二氯甲烷等鹵化烷基系溶劑；苯、甲苯等芳香族烴系溶劑；苯酚、甲酚等酚系溶劑；環戊酮等酮系溶劑；四氫呋喃、1,3-二氧戊環、1,4-二㗁烷、二甲醚、二乙醚、對甲酚甲醚等醚系溶劑。亦可視需要將2種以上之有機溶劑組合而使用。為了提高聚醯胺酸之溶解性及反應性，用於聚醯胺酸之合成之有機溶劑較佳為自醯胺系溶劑、酮系溶劑、酯系溶劑及醚系溶劑中選擇，尤其較佳為DMF、DMAC、NMP等醯胺系溶劑。 聚醯胺酸之合成反應之溫度條件並無特別限定。隨著二胺與四羧酸二酐之反應進行而生成聚醯胺酸，反應液之黏度上升。若使用1,4-環己二胺等脂環式二胺，則有形成鹽之情況，因此亦可將合成反應之溫度視需要設為50℃～150℃之範圍。鹽溶解，聚合反應開始進行之後，為了抑制因聚醯胺酸之解聚所致之分子量降低，較佳為將溫度設為80℃以下，更佳為設為0℃～50℃。反應時間只要於10分鐘～30小時之範圍內任意地設定即可。 藉由在有機溶劑中將二胺與四羧酸二酐聚合，可獲得包含聚醯胺酸及有機溶劑之聚醯胺酸溶液。該聚合溶液可直接用作聚醯胺酸溶液。又，亦可藉由自聚合溶液中去除溶劑之一部分，或添加溶劑，而調整聚醯胺酸之濃度及溶液之黏度。所添加之溶劑亦可與用於聚醯胺酸之聚合之溶劑不同。又，亦可將自聚合溶液中去除溶劑而獲得之固體之聚醯胺酸樹脂溶解於溶劑中，製備聚醯胺酸溶液。作為聚醯胺酸溶液之有機溶劑，較佳為聚醯胺酸之溶解性較高者，作為用於聚醯胺酸之合成之有機溶劑，可使用上文例示之有機溶劑。其中，較佳為DMF、DMAC、NMP等醯胺系溶劑。 藉由使聚醯胺酸脫水閉環而進行醯亞胺化。脫水閉環係藉由使用共沸溶劑之共沸法、熱方法或化學方法而進行。於以溶液之狀態進行醯亞胺化之情形時，較佳為將醯亞胺化劑及/或脫水觸媒添加至聚醯胺酸溶液中，進行化學醯亞胺化。醯亞胺化劑並無特別限定，較佳為使用三級胺，其中較佳為雜環式之三級胺。作為雜環式之三級胺，可列舉：吡啶、甲吡啶、喹啉、異喹啉、咪唑類等。作為脫水觸媒，可列舉：乙酸酐、丙酸酐、正丁酸酐、苯甲酸酐、三氟乙酸酐、γ-戊內酯等。 於自聚醯胺酸溶液中去除溶劑而進行醯亞胺化之情形時，較佳為藉由加熱進行脫水閉環之熱醯亞胺化。將聚醯胺酸加熱之方法並無特別限制，例如只要於玻璃板、金屬板、PET(聚對苯二甲酸乙二酯)等支持體上塗佈聚醯胺酸溶液之後，於80℃～500℃之範圍內進行熱處理即可。加熱時間係根據進行脫水閉環之聚醯胺酸溶液之處理量或加熱溫度而不同，一般而言較佳為處理溫度達到最高溫度之後進行1分鐘～5小時加熱。亦可於聚醯胺酸溶液中加入醯亞胺化劑及/或脫水觸媒，利用如上所述之方法進行加熱而進行醯亞胺化。 由聚醯胺酸向聚醯亞胺之醯亞胺化能以1～100%之任意比率進行，亦可合成一部分經醯亞胺化之聚醯胺酸。若進行由聚醯胺酸向聚醯亞胺之醯亞胺化，則有對有機溶劑之溶解性或溶液之黏度變化之傾向。又，以特定之醯亞胺化率停止醯亞胺化通常並不容易。於藉由溶液之塗佈及乾燥形成膜之情形時，溶液之黏度或搖變性對膜厚之均勻性產生影響。因此，若考慮到製程之穩定性，則較佳為不在聚醯胺酸中添加醯亞胺化劑及脫水觸媒，以醯亞胺化率大致為零之狀態進行向支持體上之塗佈，並藉由支持體上之加熱而進行溶劑之去除及醯亞胺化。 [聚醯胺酸及聚醯亞胺之用途] 聚醯胺酸及聚醯亞胺亦可直接用於製品或構件之製作。亦可於聚醯胺酸及聚醯亞胺中，添加熱硬化性成分、光硬化性成分、非聚合性黏合劑樹脂、染料、界面活性劑、調平劑、塑化劑、矽烷偶合劑、微粒子、增感劑等而製成組合物。該等任意成分之調配比率較佳為相對於聚醯亞胺之固形物成分總體而為0.1重量%～95重量%之範圍。再者，所謂組合物之固形物成分，係有機溶劑以外之所有成分，液狀之單體成分亦包含於固形物成分中。 本發明之聚醯亞胺由於透明性及耐熱性優異，故而可用作玻璃代替用途等之透明基板，例如可期待應用於TFT(thin film transistor，薄膜電晶體)基板、電極基板等電子器件用基板。於電子器件中，較佳為用作為液晶顯示裝置、有機EL元件、電子紙、觸控面板等必需透光性之器件用之基板。本發明之聚醯亞胺亦可用作彩色濾光片、抗反射膜、全像圖等光學構件或建築材料或構造物之材料。亦可於本發明之聚醯亞胺之表面形成金屬氧化物或透明電極等各種無機薄膜。無機薄膜例如係藉由濺鍍法、真空蒸鍍法及離子電鍍法等PVD(Physical Vapor Deposition，物理氣相沈積)法、以及CVD(Chemical Vapor Deposition，化學氣相沈積)法等乾式製程而形成。 [聚醯亞胺基板及電子器件之製作] 本發明之聚醯亞胺除了耐熱性、低熱膨脹性及透明性以外，與支持體之密接性亦良好，因此可較佳地用作利用批次製程製造之電子器件之基板。於批次製程中，於支持體上形成聚醯亞胺膜(基板)，並於其上形成元件之後，將形成有元件之聚醯亞胺基板自支持體剝離，藉此可獲得電子器件。 藉由在支持體上塗佈聚醯胺酸溶液，並進行由加熱所致之乾燥及醯亞胺化，可獲得密接積層於支持體上之聚醯亞胺膜(聚醯亞胺基板)。聚醯亞胺基板之厚度為1～200 μm左右，較佳為5～100 μm左右。 作為塗佈聚醯胺酸溶液之支持體，可列舉：玻璃基板；SUS(Steel Use Stainless，日本不鏽鋼標準)等金屬基板或金屬帶；聚對苯二甲酸乙二酯、聚碳酸酯、聚丙烯酸酯、聚萘二甲酸乙二酯、三乙醯纖維素等樹脂膜等。為適應現行之批次型之器件製造製程，較佳為使用玻璃基板作為支持體。 若於玻璃等支持體上塗佈聚醯胺酸溶液並進行加熱，則隨著溶劑之蒸發而開始聚醯胺酸之醯亞胺化，有機溶劑及因醯亞胺化(聚醯胺酸之脫水)而生成之水自聚醯胺酸溶液中揮發。此時，一部分水及/或有機溶劑並未揮發，滯留於支持體與醯亞胺化中之樹脂膜之間，成為支持體與樹脂膜之界面上之剝離之原因。滯留於支持體與樹脂膜之界面之水及/或有機溶劑係其後於以高溫進行加熱之步驟中，透射聚醯亞胺膜而排出，於產生了剝離或隆起之部分殘留氣泡。若產生此種氣泡，則於在聚醯亞胺基板上形成元件時產生異常。尤其對於薄型化或小型化之器件而言，即使微細之剝離或隆起亦對元件等之形成或安裝造成較大之影響。 具有矽氧烷結構之本發明之聚醯胺酸及聚醯亞胺由於與玻璃之密接性較高，故而於支持體上之溶劑之乾燥及醯亞胺化時，不易產生由有機溶劑或水滯留於玻璃支持體與樹脂膜之界面所致的隆起或剝離。因此，可準確地實施向密接積層於支持體上之聚醯亞胺基板上之元件之形成或安裝。又，藉由調整聚醯亞胺中之脂環式結構(通式I)與矽氧烷結構(通式II)之比率，可容易地實施形成元件後之聚醯亞胺基板的自支持體之剝離。 密接積層於支持體上之聚醯亞胺膜(聚醯亞胺基板)較佳為自支持體之90°剝離強度為0.08～5.00 N/cm，更佳為0.09～4.00 N/cm，進而較佳為0.10～3.5 N/cm。於具有上述密接性之情形時，於元件之形成及安裝製程中不易產生剝離，且元件之形成及安裝後的自支持體之剝離較容易。90°剝離強度可藉由下述實施例中記載之方法進行測定。 聚醯亞胺膜之透明性例如可根據全光線透射率及霧度進行評價。聚醯亞胺膜之全光線透射率較佳為80%以上，更佳為85%以上。霧度較佳為2.0%以下，更佳為1.0%以下。聚醯亞胺有容易吸收短波長側之光之傾向，膜本身著色為黃色之情況較多。為了製成著色較少之膜，聚醯亞胺膜之波長450 nm之光透射率較佳為70%以上，更佳為75%以上。本發明之聚醯亞胺較佳為形成膜厚10 μm之膜時之全光線透射率、霧度及波長450 nm之光透射率為上述範圍。 包含本發明之聚醯亞胺之聚醯亞胺基板係線熱膨脹較小，加熱前後之尺寸穩定性優異。聚醯亞胺膜之線熱膨脹係數較佳為30 ppm/K以下，更佳為20 ppm/K以下。線熱膨脹係數可藉由下述實施例中記載之方法進行測定。本發明之聚醯亞胺較佳為形成膜厚10 μm之膜時之線熱膨脹係數為上述範圍。 [實施例] [聚醯胺酸溶液之製備] ＜實施例1＞ 於安裝有具備不鏽鋼製攪拌翼之攪拌機及氮氣導入管之500 mL之玻璃製可分離式燒瓶中，添加反式-1,4-環己二胺(CHDA)8.38 g、及N-甲基-2-吡咯啶酮(NMP)170.0 g，並於室溫(23℃)下進行攪拌而使之溶解。以目視確認CHDA之溶解後，添加1,3-雙(3-胺基丙基)四甲基二矽氧烷(PAM-E)0.02 g，進而進行攪拌。於該溶液中，加入3,3',4,4'-聯苯四羧酸酐(BPDA)21.61 g，並於80℃下加熱1小時之後，於室溫下攪拌5小時，獲得聚醯胺酸溶液。該反應溶液中之二胺及四羧酸二酐之添加濃度係相對於反應溶液總量而為15重量%。 ＜實施例2＞ 將CHDA之添加量變更為8.37 g，將PAM-E之添加量變更為0.04 g，且將BPDA之添加量變更為21.60 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜實施例3＞ 將CHDA之添加量變更為8.36 g，將PAM-E之添加量變更為0.06 g，且將BPDA之添加量變更為21.59 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜實施例4＞ 將CHDA之添加量變更為8.33 g，將PAM-E之添加量變更為0.09 g，且將BPDA之添加量變更為21.58 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜實施例5＞ 將CHDA之添加量變更為8.30 g，將PAM-E之添加量變更為0.13 g，且將BPDA之添加量變更為21.56 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜實施例6＞ 將CHDA之添加量變更為8.28 g，將PAM-E之添加量變更為0.18 g，且將BPDA之添加量變更為21.54 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜實施例7＞ 將CHDA之添加量變更為8.06 g，將PAM-E之添加量變更為0.54 g，且將BPDA之添加量變更為21.40 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜實施例8＞ 將CHDA之添加量變更為7.84 g，將PAM-E之添加量變更為0.90 g，且將BPDA之添加量變更為21.26 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜比較例1＞ 將CHDA之添加量變更為8.39 g，不添加PAM-E而添加BPDA 21.61 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜比較例2＞ 於比較例1中合成之聚醯胺酸溶液中，添加相對於聚醯胺酸而為0.1重量%之矽烷偶合劑：γ-胺基丙基三乙氧基矽烷，並攪拌24小時，製備烷氧基矽烷改性聚醯胺酸溶液。 ＜比較例3＞ 將CHDA之添加量變更為8.36 g，不添加PAM-E，同時加入BPDA 21.31 g與9,9-雙(3,4-二羧基苯基)茀酸二酐(以下稱為BPAF)0.335 g，除此以外，藉由與實施例1相同之方式獲得聚醯胺酸溶液。 ＜比較例4＞ 於安裝有具備不鏽鋼製攪拌翼之攪拌機及氮氣導入管之500 mL之玻璃製可分離式燒瓶中，添加對苯二胺(PDA)7.98 g及NMP 170.0 g，並於室溫下進行攪拌而使之溶解。以目視確認PDA之溶解之後，添加PAM-E 0.19 g，進而進行攪拌。其後，加入BPDA 21.83 g，於50℃下進行攪拌直至溶解之後，將溶液之溫度調整為約90℃，並繼續攪拌，降低溶液之黏度，獲得23℃下之黏度為28,800 mPa・s之聚醯胺酸溶液。 ＜比較例5＞ 於安裝有具備不鏽鋼製攪拌翼之攪拌機及氮氣導入管之500 mL之玻璃製可分離式燒瓶中，添加CHDA 8.34 g及NMP 170.0 g，於室溫下進行攪拌而使之溶解。以目視確認CHDA之溶解之後，添加Shin-Etsu Silicones製造之反應性聚矽氧油：KF-8010(胺當量：430 g/mol)0.13 g，進而進行攪拌。於該溶液中，加入BPDA 21.53 g，於80℃下加熱1小時，其後進行冷卻，於室溫(23℃)下攪拌5小時，獲得聚醯胺酸溶液。 ＜比較例6＞ 將CHDA之添加量變更為8.36 g，將BPDA之添加量變更為21.50 g，作為反應性聚矽氧油，代替KF-8010而添加Shin-Etsu Silicones製造之反應性聚矽氧油：X-22-168AS(酸酐當量：500 g/mol)0.15 g。除該等變更點以外，藉由與比較例5相同之方式獲得聚醯胺酸溶液。 [聚醯胺酸之評價] ＜分子量＞ 以表1之條件求出重量平均分子量(Mw)。 [表1]

[聚醯亞胺膜之製作] 利用NMP將上述實施例及比較例中獲得之聚醯胺酸溶液以固形物成分濃度成為10%之方式稀釋。使用棒式塗佈機，將經稀釋之溶液以乾燥後之厚度成為10 μm之方式流延至150 mm×150 mm之無鹼玻璃板(Corning公司製造之 Eagle XG，厚度0.7 mm)上，並於熱風烘箱內於80℃下乾燥30分鐘，於玻璃板上形成聚醯胺酸之塗膜。將玻璃板與聚醯胺酸塗膜之積層體於氮氣環境下以5℃/分鐘自20℃升溫至350℃之後，於350℃下加熱1小時，進行塗膜之醯亞胺化，獲得聚醯亞胺膜與玻璃之積層體。僅比較例4中，以乾燥後之厚度成為20 μm之方式進行聚醯胺酸溶液之流延，並將熱風烘箱內之乾燥溫度設為120℃，於氮氣環境下以升溫速度7℃/分鐘進行升溫直至450℃之後，於450℃下加熱10分鐘，實施醯亞胺化。 於比較例1中，確認到於玻璃與聚醯亞胺膜之間有較多氣泡。除了比較例1以外，未確認到由聚醯亞胺膜之剝離所引起之氣泡。另一方面，於實施例8中，玻璃與聚醯亞胺膜之密接性較高，無法自玻璃剝離，因此不實施下述物性評價。 [聚醯亞胺膜之評價] ＜剝離強度＞ 將玻璃板與聚醯亞胺膜之積層體於23℃55%RH之環境下靜置24小時而進行調濕後，依據ASTM D1876-01標準測定90°剝離強度。利用截切刀於聚醯亞胺膜中切入10 mm寬之切口，使用東洋精機製造之拉伸試驗機(Strograph VES1D)，於23℃55%RH條件下以拉伸速度50 mm/分鐘、剝離長度50 mm實施90°剝離試驗，將剝離強度之平均值作為剝離強度。於實施例6及實施例7中，剝離強度超過荷重元之最大荷重(5.0 N)。 ＜線熱膨脹係數(CTE)＞ 線熱膨脹係數之測定係使用Hitachi High-Tech Science公司製造之TMA/SS7100(試樣尺寸：寬度3 mm×長度10 mm；測定膜厚，算出膜之剖面積)，設為荷重29.4 mN，以10℃/分鐘自10℃暫時升溫至350℃之後，以40℃/分鐘降溫，根據降溫時之100～300℃下之每單位溫度之試樣之應變之變化量求出線膨脹係數。 ＜光透射率＞ 使用日本分光公司製造之紫外可見近紅外分光光度計(V-650)，測定200～800 nm之光透射率，將450 nm之波長之光透射率作為聚醯亞胺膜之透射率。 ＜聚醯亞胺膜之全光線透射率(TT)及霧度＞ 藉由日本電色工業製造之積分球式霧度計300A，利用JIS K7105-1981記載之方法進行測定。 將實施例及比較例之聚醯胺酸聚合時之單體添加量(酸二酐及二胺各自之莫耳比)、聚醯胺酸之重量平均分子量及改性之有無、聚醯亞胺膜之膜厚、醯亞胺化時之自玻璃板之剝離之有無、聚醯亞胺膜之自玻璃板之剝離強度、以及聚醯亞胺膜之特性之評價結果示於表2。 [表2]

由作為酸二酐之BPDA與作為二胺之CHDA獲得的比較例1之聚醯胺酸溶液係於塗佈於玻璃板上之後之熱醯亞胺化時，於玻璃板與聚醯亞胺膜之間產生較多氣泡，塗佈面積之25%以上自玻璃板剝離。於藉由矽烷偶合劑將比較例1之聚醯胺酸改性之比較例2中，若與比較例1相比，則與玻璃板之密接性提高，但剝離強度較小，密接性不可謂充分。於作為酸二酐而於BPDA中添加1莫耳%之BPAF的比較例3中亦相同。 於在單體成分中添加反應性聚矽氧油之比較例5及比較例6中，若與比較例1相比，則與玻璃板之密接性提高，但剝離強度較小，密接性不充分。又，於比較例5及比較例6中，所獲得之聚醯亞胺膜之線熱膨脹係數(CTE)較高，尺寸穩定性較差，透明性降低。 除了CHDA以外使用具有矽氧烷結構之PAM-E作為二胺成分之實施例1～8均對玻璃顯示出良好之密接性。CHDA/PAM-E之莫耳數之比m_A /m_B 為97/3～99.0/0.1之實施例1～7均維持了與比較例1同等之低CTE及高透明性。於CHDA/PAM-E之莫耳數之比m_A /m_B 為95/5之實施例8，未進行聚醯亞胺膜之特性評價，但於形成於玻璃板上之聚醯亞胺膜之目視時，具有與實施例1～7相同之透明性。又，實施例8係聚醯胺酸及聚醯亞胺之組成與實施例7類似，因此推測維持與實施例7相同之低CTE及高透明性。於使用PDA代替CHDA之比較例4中，顯示出與實施例1、2等同等之剝離強度，但透明性(尤其是可見光短波長側)大幅度地降低，可見著色。 於實施例1～8中，可見伴隨PAM-E之添加量之增加而剝離強度增加，與玻璃之密接性提高之傾向。若考慮到於玻璃板上形成聚醯亞胺膜，視需要進行向聚醯亞胺膜上之元件之形成或安裝之後，自玻璃板剝離聚醯亞胺膜時之剝離之容易性，則可認為含矽氧烷結構之二胺之使用量係相對於二胺總量而較佳為5莫耳%以下，尤佳為1莫耳%以下。 如根據上述實施例與比較例之對比可理解般，本發明之聚醯胺酸係向玻璃支持體上之膜形成及加熱醯亞胺化時之加工性良好，與玻璃支持體之密接性優異。藉由本發明之聚醯胺酸之醯亞胺化所獲得之聚醯亞胺膜於100～300℃之高溫區域中亦具有低熱膨脹性，且具有高透明性，因此可期待作為代替玻璃之透明基板材料之應用。[Structures of polyamide acid and polyimide] The polyamide acid of the present invention includes a structural unit represented by general formula 1 and a structural unit represented by general formula 2 below. [化9]

[化10]

The polyimide of the present invention includes the structural unit represented by the following general formula I and the structural unit represented by the general formula II. For example, the polyimide having the above-mentioned structure 1 and structure 2 can be imidized And get. [化11]

[化12]

The A in the general formula 1 and the general formula I, and the B in the general formula 2 and the general formula II are all tetravalent aromatic groups. The aromatic group may have a single aromatic ring, may be formed by bonding a plurality of aromatic rings, or may be a condensed polycyclic ring. In the above general formula 2 and the above general formula II, R ¹ and R ² are each independently a divalent hydrocarbon group, and n is an integer of 1-5. By imidizing the polyamide containing the structural unit of the above general formula 1 and the structural unit of the above general formula 2, the polyamide containing the structural unit of the general formula I and the structural unit of the general formula II can be obtained. amine. The polyimide system with this structure has excellent adhesion to glass, so it is suitable for the formation of resin film substrates in a batch process and the process of forming components on the film substrate. The above A and B are preferably residues of aromatic tetracarboxylic dianhydride. Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3',4,4-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-benzophenone Tetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenyltetracarboxylic dianhydride, 1,4,5,8 -Naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride , 9,9-bis(3,4-dicarboxyphenyl) dianhydride, 9,9'-bis[4-(3,4-dicarboxyphenoxy)phenyl] dianhydride, 3,3 ',4,4'-Diphenyl ether tetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 4,4' -Sulfonyl diphthalic dianhydride, terphenyl-3,4,3',4'-tetracarboxylic dianhydride, m-triphenyl-3,3',4,4'-tetracarboxylic acid Although dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, etc. are not limited to these. A in general formula 1 and general formula I and B in general formula 2 and general formula II may be the same or different. For polyimides with high transparency and low linear expansion coefficient, A is particularly preferably the residue of 3,3',4,4'-biphenyltetracarboxylic dianhydride (as represented by the following chemical formula Biphenyl-3,3',4,4'-tetrakis). [化13]

That is, the structural unit of the general formula 1 is preferably the amide structural unit represented by the following formula 1A, and the structural unit of the general formula I is preferably the imine structural unit represented by the following formula IA. These structural units can be obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride and 1,4-cyclohexanediamine. [化14]

[化15]

In terms of obtaining polyimide with high transparency and low linear expansion coefficient, B is particularly preferably a residue of 3,3',4,4'-biphenyltetracarboxylic dianhydride. That is, the structural unit represented by the general formula 2 is preferably the amide structural unit represented by the following general formula 2A, and the structural unit represented by the general formula II is preferably the imine structure represented by the following general formula IIA unit. These structural units can be obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride and diamine containing siloxane structure. [化16]

[化17]

As mentioned above, A and B can also be the same. From the viewpoint of simultaneously achieving high transparency and low linear expansion coefficient of the polyimide film, both A and B are preferably biphenyl-3,3',4,4'-tetrayl. As far as the reactivity of polyamide acid during polymerization is excellent, and the polyimide shows low thermal expansion, R ¹ and R ² in the above general formula 2 and the above general formula II are each independently preferably methylene Ethylene group, ethylene group or propylene group, of which propylene group is particularly preferred. In terms of polyamide acid showing high solubility and polyimide film showing high transparency, n in the above general formula 2 and the above general formula II is preferably 1 to 5, more preferably 1 ~3, the best is 1. That is, the structural unit of the general formula 2 is preferably the amide structural unit represented by the following general formula 2B, and the structural unit of the general formula II is preferably the imine structural unit represented by the following general formula IIB. These structural units can be obtained from aromatic tetracarboxylic dianhydride and 1,3-bis(3-aminopropyl)tetramethyldisiloxane as the diamine component. [化18]

[化19]

As described above, the tetravalent aromatic group B in Formula 2 and Formula II is preferably biphenyl-3,3',4,4'-tetrayl. Therefore, the structural unit of the general formula 2 is particularly preferably the amide structural unit represented by the following formula 2C, and the structural unit of the general formula II is particularly preferably the imine structural unit represented by the following formula IIC. These structural units can be obtained from 3,3',4,4'-biphenyltetracarboxylic dianhydride and 1,3-bis(3-aminopropyl)tetramethyldisiloxane. [化20]

[化21]

From the viewpoint of making the polyimide film have high heat resistance, low thermal expansion, high transparency, and moderate adhesion to glass, the structural unit represented by the general formula I in the polyimide is the same as the general formula II The total of the structural units shown is preferably 80 mol% or more, more preferably 90 mol% or more, and particularly preferably 95 mol% or more with respect to the total amount of polyimide. In order to set the total of the structural unit represented by the general formula I and the structural unit represented by the general formula II within the above range, the structural unit represented by the general formula 1 in the polyamide acid as the precursor is represented by the general formula 2 The total of the structural units is preferably 80 mol% or more, more preferably 90 mol% or more, and particularly preferably 95 mol% or more with respect to the total amount of polyamide acid. The so-called molar number of polyimine is derived from the molar number of the structural units of all diamines constituting the polyimine. The so-called molar number of polyamide acid is derived from the molar number of the structural units of all diamines constituting the polyamide acid. Since polyimines and polyamide acids contain equal-molar structural units derived from diamines and structural units derived from acid dianhydrides, they are derived from all diamines in polyimines and polyamides. The molar number of the structural unit is equal to the molar number of the structural unit derived from all acid dianhydrides. From the viewpoint of obtaining a polyimide having moderate adhesion to the support in addition to high transparency and low thermal expansion, the molar number M _{A of the structural unit represented by the general formula I in the polyimide} The ratio M _A /M _{B to the molar number M B} of the structural unit represented by the general formula II is preferably in the range of 95.0/5.0 to 99.9/0.1. That is, the polyimide of the present invention is preferably that most of the diamine component is 1,4-cyclohexanediamine and contains a small amount of 1,3-bis(3-aminopropyl)tetramethyldisilica Diamines containing siloxane structures such as oxanes. By introducing a small amount of silicone structure into the diamine component, there is a tendency for the adhesion of polyimine to support such as glass to be improved. Therefore, when the polyimide solution is applied to the support and the imidization is performed, peeling or swelling between the polyimide and the support can be suppressed. As the content of the siloxane structure increases, there is a tendency for the adhesion to glass and the like to improve. On the other hand, if the adhesiveness is too high, it may become difficult to peel the polyimide film from the support, resulting in a dimensional change or opacity during peeling. If M _A /M _B is 95.0/5.0 or more, peeling of the polyimide film from the support after the formation of electronic components and the like on the polyimide film can be carried out without any problems. In addition, if M _A /M _B is 95.0/5.0 or more, the low thermal expansion characteristics and high transparency of the polyimide film can be maintained. M _A /M _{B is more} preferably 96.0/4.0 to 99.8/0.2, still more preferably 97.0/3.0 to 99.7/0.3, particularly preferably 98.0/2.0 to 99.6/0.4, most preferably 99.0/1.0 to 99.5/0.5. In order to set the ratio of the structural unit represented by the general formula I in the polyimine to the structural unit represented by the general formula II in the above range, the structural unit represented by the general formula 1 in the polyimide as the precursor The ratio of the molar number m _{A to the molar number m B} of the structural unit represented by the general formula 2, _{m A} /m _{B is} preferably in the range of 95.0/5.0 to 99.9/0.1, more preferably 96.0/4.0 to 99.8/ 0.2, more preferably 97.0/3.0 to 99.7/0.3, particularly preferably 98.0/2.0 to 99.6/0.4, most preferably 99.0/1.0 to 99.6/0.4. The polyamide acid and polyimine of the present invention are preferably obtained by gel permeation chromatography (GPC, Gel Permeation Chromatography) with a weight average molecular weight of 10,000 to 500,000 in terms of polyethylene oxide, more preferably 20,000 ~300,000, more preferably 30,000~200,000. If the weight average molecular weight is 10,000 or more, polyamide acid and polyimide can be made into a coating or film. On the other hand, if the weight average molecular weight is 500,000 or less, it exhibits sufficient solubility in solvents, and therefore it is easy to obtain a coating film or film with a smooth surface and a uniform film thickness. [Synthesis of polyimide and polyimide] The polyimide containing the above-mentioned structure I and structure II can be obtained by a known method. Polyimine can be synthesized by a synthesis method using a precursor such as polyamide acid or polyimide ester, and a synthesis method without using a precursor. In terms of monomer availability and ease of polymerization, it is preferable to synthesize polyimide by imidization of polyamide as a precursor. The polyamide acid containing the above structure 1 and structure 2 can be obtained by reacting diamine and tetracarboxylic dianhydride in an organic solvent. For example, as long as the diamine is dissolved or dispersed in the organic solvent in the form of a slurry, the diamine solution is made, and the tetracarboxylic dianhydride is dissolved or dispersed in the organic solvent in the form of a slurry. The state of the solution or solid Just add it to the above diamine solution. Diamine can also be added to the tetracarboxylic dianhydride solution. The dissolution and reaction of diamine and tetracarboxylic dianhydride are preferably carried out in an inert gas environment such as argon and nitrogen. In the synthesis of polyamide acid, it is preferable to adjust the molar number of the total amount of the diamine component and the molar number of the total amount of the tetracarboxylic dianhydride component to substantially equal molar. By using plural kinds of diamines and/or plural kinds of tetracarboxylic dianhydrides, polyamide acids having plural kinds of structures can be obtained. In addition, by blending polyamides with different structures, polyamides with multiple structural units with different structures can be obtained. By using aromatic tetracarboxylic dianhydride as the tetracarboxylic dianhydride, and using 1,4-cyclohexanediamine and a siloxane-containing diamine as the diamine, a structure containing general formula 1 can be obtained The unit and the polyamide acid of the structural unit represented by the general formula 2. By using 3,3',4,4'-biphenyltetracarboxylic dianhydride as the aromatic diamine, and 1,3-bis(3-aminopropyl)tetramethyldisiloxane as the containing The diamine of the siloxane structure can obtain the polyamide containing the amic acid structural unit represented by formula 1A and the amic acid structural unit represented by formula 1C. By setting the ratio of the number of moles of 1,4-cyclohexanediamine to the number of moles of siloxane-containing diamine in the range of 95.0/5.0 to 99.9/0.1, m _A /m _B can be obtained as Polyamide acid in the range of 95.0/5.0 to 99.9/0.1. The organic solvent used in the synthesis reaction of polyamide acid is not particularly limited. Preferably, the organic solvent can dissolve the tetracarboxylic dianhydride and diamines used, and can dissolve the polyamide acid produced by polymerization. Specific examples of organic solvents include: urea-based solvents such as tetramethylurea and N,N-dimethylethylurea; Solvent; N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), N,N'-diethylacetamide, N-methyl-2-pyrrole Ester solvents such as pyridone (NMP) and γ-butyrolactone; amide solvents such as hexamethylphosphatidylamine; halogenated alkyl solvents such as chloroform and dichloromethane; aromatic hydrocarbon solvents such as benzene and toluene ; Phenolic solvents such as phenol and cresol; ketone solvents such as cyclopentanone; tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, dimethyl ether, diethyl ether, p-cresol methyl ether, etc. Ether solvent. It can also be used in combination with two or more organic solvents as needed. In order to improve the solubility and reactivity of polyamide acid, the organic solvent used in the synthesis of polyamide acid is preferably selected from amide solvents, ketone solvents, ester solvents and ether solvents, especially preferred It is an amide-based solvent such as DMF, DMAC, and NMP. The temperature conditions for the synthesis reaction of polyamide acid are not particularly limited. As the reaction of diamine and tetracarboxylic dianhydride proceeds to produce polyamide acid, the viscosity of the reaction liquid increases. If an alicyclic diamine such as 1,4-cyclohexanediamine is used, a salt may be formed. Therefore, the temperature of the synthesis reaction may be set in the range of 50°C to 150°C as necessary. After the salt is dissolved and the polymerization reaction starts, in order to suppress the decrease in molecular weight due to the depolymerization of the polyamide acid, the temperature is preferably set to 80°C or lower, more preferably 0°C to 50°C. The reaction time may be arbitrarily set within the range of 10 minutes to 30 hours. By polymerizing diamine and tetracarboxylic dianhydride in an organic solvent, a polyamic acid solution containing polyamic acid and an organic solvent can be obtained. The polymerization solution can be directly used as a polyamide acid solution. In addition, it is also possible to adjust the concentration of polyamide acid and the viscosity of the solution by removing part of the solvent from the polymerization solution or adding a solvent. The added solvent may also be different from the solvent used for the polymerization of polyamide acid. In addition, the solid polyamide resin obtained by removing the solvent from the polymerization solution may be dissolved in the solvent to prepare a polyamide acid solution. The organic solvent of the polyamide acid solution is preferably one with higher solubility of polyamide acid. As the organic solvent used in the synthesis of polyamide acid, the organic solvents exemplified above can be used. Among them, amide-based solvents such as DMF, DMAC, and NMP are preferred. The imidization is carried out by dehydrating and ring-closing the polyamide acid. The dehydration ring-closure system is performed by azeotropic, thermal, or chemical methods using azeotropic solvents. In the case of performing the imidization in the state of a solution, it is preferable to add an imidization agent and/or a dehydration catalyst to the polyamide acid solution for chemical imidization. The imidinating agent is not particularly limited, and it is preferable to use a tertiary amine, and among them, a heterocyclic tertiary amine is preferable. Examples of tertiary amines of the heterocyclic ring include pyridine, picoline, quinoline, isoquinoline, imidazoles, and the like. Examples of the dehydration catalyst include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride, and γ-valerolactone. In the case of removing the solvent from the polyamic acid solution to perform the imidization, it is preferable to perform the thermal imidization of dehydration and ring closure by heating. The method of heating the polyamide acid is not particularly limited. For example, as long as the polyamide acid solution is coated on a support such as a glass plate, a metal plate, and PET (polyethylene terephthalate), the temperature is 80°C~ The heat treatment can be performed within the range of 500°C. The heating time varies according to the processing amount or heating temperature of the polyamide acid solution for dehydration and ring closure. Generally, it is preferable to perform heating for 1 minute to 5 hours after the processing temperature reaches the maximum temperature. It is also possible to add an imidization agent and/or a dehydration catalyst to the polyamide acid solution, and heat the polyamide solution to perform the imidization using the method described above. The imidization of polyamide to polyimid can be carried out at any ratio of 1-100%, and a part of polyimidized polyimid can also be synthesized. If the imidization of polyamide acid to polyimide is carried out, the solubility to the organic solvent or the viscosity of the solution tends to change. In addition, it is usually not easy to stop the imidization with a specific imidization rate. When a film is formed by coating and drying the solution, the viscosity or thixotropy of the solution affects the uniformity of the film thickness. Therefore, if the stability of the process is taken into consideration, it is better not to add an imidizing agent and dehydrating catalyst to the polyamide, and to coat the support with the imidization rate of approximately zero. , And the solvent is removed and imidized by heating on the support. [Uses of polyamide acid and polyimide] Polyamide acid and polyimide can also be directly used in the production of products or components. It is also possible to add thermosetting components, light curing components, non-polymerizable binder resins, dyes, surfactants, leveling agents, plasticizers, silane coupling agents, to polyamide acids and polyimides, Fine particles, sensitizer, etc. are made into a composition. The blending ratio of these optional components is preferably in the range of 0.1% by weight to 95% by weight with respect to the total solid components of the polyimide. Furthermore, the so-called solid component of the composition refers to all components other than the organic solvent, and the liquid monomer component is also included in the solid component. Since the polyimide of the present invention is excellent in transparency and heat resistance, it can be used as a transparent substrate for glass replacement applications. For example, it is expected to be applied to electronic devices such as TFT (thin film transistor) substrates and electrode substrates. Substrate. Among electronic devices, it is preferably used as a substrate for devices that require light permeability, such as liquid crystal display devices, organic EL elements, electronic paper, and touch panels. The polyimide of the present invention can also be used as a color filter, anti-reflection film, holographic image and other optical components or building materials or structural materials. Various inorganic thin films such as metal oxides or transparent electrodes can also be formed on the surface of the polyimide of the present invention. Inorganic thin films are formed by, for example, PVD (Physical Vapor Deposition) methods such as sputtering, vacuum evaporation, and ion plating, and dry processes such as CVD (Chemical Vapor Deposition) methods. . [Production of polyimide substrates and electronic devices] In addition to heat resistance, low thermal expansion, and transparency, the polyimide of the present invention also has good adhesion to the support, so it can be preferably used as a batch The substrate of electronic devices manufactured by the process. In the batch process, a polyimide film (substrate) is formed on a support, and after forming elements on it, the polyimide substrate on which the elements are formed is peeled from the support, thereby obtaining electronic devices. By coating a polyimide solution on the support, and performing drying and imidization by heating, a polyimide film (polyimide substrate) that is closely laminated on the support can be obtained. The thickness of the polyimide substrate is about 1 to 200 μm, preferably about 5 to 100 μm. Examples of the support for coating the polyamide acid solution include: glass substrates; metal substrates or metal tapes such as SUS (Steel Use Stainless, Japanese stainless steel standards); polyethylene terephthalate, polycarbonate, and polyacrylic acid Resin films such as esters, polyethylene naphthalate, triacetyl cellulose, etc. In order to adapt to the current batch-type device manufacturing process, it is preferable to use a glass substrate as a support. If the polyamide acid solution is coated on a support such as glass and heated, as the solvent evaporates, the imidization of the polyamide starts, and the organic solvent and the imidization of the polyamide (polyamide Dehydration) and the resulting water volatilizes from the polyamide acid solution. At this time, part of the water and/or organic solvent did not volatilize, and stayed between the support and the resin film in the imidization process, which became the cause of peeling at the interface between the support and the resin film. The water and/or organic solvent remaining at the interface between the support and the resin film are subsequently passed through the polyimide film and discharged in the step of heating at a high temperature, leaving air bubbles in the part where peeling or bulging has occurred. If such bubbles are generated, an abnormality occurs when the device is formed on the polyimide substrate. Especially for thinner or miniaturized devices, even fine peeling or swelling will have a greater impact on the formation or mounting of components, etc. The polyamide acid and polyimide of the present invention having a siloxane structure have higher adhesion to glass, so when the solvent on the support is dried and imidized, it is difficult to produce organic solvents or water. Swelling or peeling caused by staying at the interface between the glass support and the resin film. Therefore, it is possible to accurately perform the formation or mounting of the device on the polyimide substrate laminated on the support in close contact. In addition, by adjusting the ratio of the alicyclic structure (general formula I) and the silicone structure (general formula II) in the polyimide, the self-supporting body of the polyimide substrate after forming the device can be easily implemented之 stripping. The polyimide film (polyimide substrate) closely laminated on the support preferably has a 90° peel strength from the support of 0.08 to 5.00 N/cm, more preferably 0.09 to 4.00 N/cm, and more Preferably, it is 0.10～3.5 N/cm. In the case of the above-mentioned adhesiveness, it is not easy to peel off during the formation and mounting process of the element, and the formation of the element and the peeling of the self-supporting body after mounting are easier. The 90° peel strength can be measured by the method described in the following examples. The transparency of the polyimide film can be evaluated based on, for example, total light transmittance and haze. The total light transmittance of the polyimide film is preferably 80% or more, more preferably 85% or more. The haze is preferably 2.0% or less, more preferably 1.0% or less. Polyimide tends to easily absorb light on the short-wavelength side, and the film itself is often colored yellow. In order to form a film with less coloration, the light transmittance of the polyimide film at a wavelength of 450 nm is preferably 70% or more, and more preferably 75% or more. The polyimide of the present invention preferably has a total light transmittance, haze, and light transmittance at a wavelength of 450 nm when a film with a thickness of 10 μm is formed in the above-mentioned range. The polyimide substrate containing the polyimide of the present invention has low linear thermal expansion and excellent dimensional stability before and after heating. The coefficient of linear thermal expansion of the polyimide film is preferably 30 ppm/K or less, more preferably 20 ppm/K or less. The coefficient of linear thermal expansion can be measured by the method described in the following Examples. The polyimide of the present invention preferably has a linear thermal expansion coefficient in the above-mentioned range when a film with a film thickness of 10 μm is formed. [Example] [Preparation of polyamide acid solution] <Example 1> In a 500 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring blade and a nitrogen introduction tube, trans-1, 8.38 g of 4-cyclohexanediamine (CHDA) and 170.0 g of N-methyl-2-pyrrolidone (NMP) were stirred and dissolved at room temperature (23°C). After visually confirming the dissolution of CHDA, 0.02 g of 1,3-bis(3-aminopropyl)tetramethyldisiloxane (PAM-E) was added, followed by stirring. To this solution, 21.61 g of 3,3',4,4'-biphenyltetracarboxylic anhydride (BPDA) was added and heated at 80°C for 1 hour, and then stirred at room temperature for 5 hours to obtain polyamide acid Solution. The added concentration of diamine and tetracarboxylic dianhydride in the reaction solution is 15% by weight with respect to the total amount of the reaction solution. <Example 2> The addition amount of CHDA was changed to 8.37 g, the addition amount of PAM-E was changed to 0.04 g, and the addition amount of BPDA was changed to 21.60 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Example 3> The addition amount of CHDA was changed to 8.36 g, the addition amount of PAM-E was changed to 0.06 g, and the addition amount of BPDA was changed to 21.59 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Example 4> The addition amount of CHDA was changed to 8.33 g, the addition amount of PAM-E was changed to 0.09 g, and the addition amount of BPDA was changed to 21.58 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Example 5> The addition amount of CHDA was changed to 8.30 g, the addition amount of PAM-E was changed to 0.13 g, and the addition amount of BPDA was changed to 21.56 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Example 6> The addition amount of CHDA was changed to 8.28 g, the addition amount of PAM-E was changed to 0.18 g, and the addition amount of BPDA was changed to 21.54 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Example 7> The addition amount of CHDA was changed to 8.06 g, the addition amount of PAM-E was changed to 0.54 g, and the addition amount of BPDA was changed to 21.40 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Example 8> The addition amount of CHDA was changed to 7.84 g, the addition amount of PAM-E was changed to 0.90 g, and the addition amount of BPDA was changed to 21.26 g, except that the same as in Example 1 Way to obtain a polyamide acid solution. <Comparative Example 1> The addition amount of CHDA was changed to 8.39 g, and PAM-E was not added, but 21.61 g of BPDA was added. In the same manner as in Example 1, a polyamide acid solution was obtained. <Comparative Example 2> In the polyamide acid solution synthesized in Comparative Example 1, 0.1% by weight of silane coupling agent: γ-aminopropyltriethoxysilane was added to the polyamide acid solution, and stirred For 24 hours, prepare the alkoxysilane modified polyamide acid solution. <Comparative Example 3> The addition amount of CHDA was changed to 8.36 g, PAM-E was not added, and 21.31 g of BPDA and 9,9-bis(3,4-dicarboxyphenyl) dianhydride (hereinafter referred to as BPAF) 0.335 g, except for this, a polyamide acid solution was obtained in the same manner as in Example 1. <Comparative Example 4> In a 500 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring blade and a nitrogen inlet tube, 7.98 g of p-phenylenediamine (PDA) and 170.0 g of NMP were added, and kept at room temperature Stir it down to dissolve it. After visually confirming the dissolution of PDA, 0.19 g of PAM-E was added, followed by stirring. After that, 21.83 g of BPDA was added and stirred at 50°C until it was dissolved. After that, the temperature of the solution was adjusted to about 90°C, and the stirring was continued to reduce the viscosity of the solution to obtain a polymer with a viscosity of 28,800 mPa·s at 23°C. Amino acid solution. <Comparative Example 5> In a 500 mL glass separable flask equipped with a stirrer equipped with a stainless steel stirring blade and a nitrogen inlet tube, add 8.34 g of CHDA and 170.0 g of NMP, and stir at room temperature to dissolve it . After visually confirming the dissolution of CHDA, 0.13 g of reactive silicone oil manufactured by Shin-Etsu Silicones: KF-8010 (amine equivalent: 430 g/mol) was added, and then stirred. To this solution, 21.53 g of BPDA was added, heated at 80°C for 1 hour, then cooled, and stirred at room temperature (23°C) for 5 hours to obtain a polyamide acid solution. <Comparative Example 6> The addition amount of CHDA was changed to 8.36 g, and the addition amount of BPDA was changed to 21.50 g. As a reactive silicone oil, instead of KF-8010, a reactive silicone made by Shin-Etsu Silicones was added. Oil: X-22-168AS (anhydride equivalent: 500 g/mol) 0.15 g. Except for these changes, a polyamide acid solution was obtained in the same manner as in Comparative Example 5. [Evaluation of polyamide acid] <Molecular weight> The weight average molecular weight (Mw) was determined under the conditions of Table 1. [Table 1]

[Production of polyimide film] The polyimide acid solution obtained in the above examples and comparative examples was diluted with NMP so that the solid content concentration became 10%. Using a bar coater, cast the diluted solution onto a 150 mm×150 mm alkali-free glass plate (Eagle XG manufactured by Corning, thickness 0.7 mm) in such a way that the thickness after drying becomes 10 μm. Dry in a hot air oven at 80°C for 30 minutes to form a polyamide coating film on the glass plate. The laminate of the glass plate and the polyamide coating film was heated from 20°C to 350°C at 5°C/min in a nitrogen atmosphere, and then heated at 350°C for 1 hour to perform imidization of the coating film to obtain poly Laminated body of imine film and glass. In Comparative Example 4 only, the polyamide acid solution was cast so that the thickness after drying became 20 μm, and the drying temperature in the hot-air oven was set to 120°C, and the heating rate was 7°C/min in a nitrogen environment After raising the temperature to 450°C, it was heated at 450°C for 10 minutes to implement imidization. In Comparative Example 1, it was confirmed that there were many bubbles between the glass and the polyimide film. Except for Comparative Example 1, no bubbles caused by peeling of the polyimide film were confirmed. On the other hand, in Example 8, the adhesiveness between the glass and the polyimide film was high, and the glass could not be peeled off, so the following physical property evaluation was not performed. [Evaluation of polyimide film] <Peeling strength> The laminated body of the glass plate and polyimide film is placed in an environment of 23°C and 55%RH for 24 hours to adjust the humidity, according to ASTM D1876-01 standard The 90° peel strength was measured. Use a cutting knife to cut a 10 mm wide incision in the polyimide film. Use a tensile testing machine (Strograph VES1D) manufactured by Toyo Seiki to peel off at a tensile speed of 50 mm/min at 23°C and 55% RH. A 90° peel test was performed for a length of 50 mm, and the average value of the peel strength was taken as the peel strength. In Example 6 and Example 7, the peel strength exceeded the maximum load (5.0 N) of the load cell. <Coefficient of Linear Thermal Expansion (CTE)> The measurement of the coefficient of linear thermal expansion uses Hitachi High-Tech Science's TMA/SS7100 (sample size: width 3 mm × length 10 mm; measure the film thickness and calculate the cross-sectional area of the film), Set the load to 29.4 mN, and after temporarily raising the temperature from 10°C to 350°C at 10°C/min, the temperature will be lowered at 40°C/min. Determine the amount of change in the strain per unit temperature of the sample at 100-300°C during the temperature drop. Outlet expansion coefficient. <Light transmittance> Use the UV-visible near-infrared spectrophotometer (V-650) manufactured by JASCO Corporation to measure the light transmittance of 200～800 nm, and use the light transmittance of the wavelength of 450 nm as the polyimide film Transmittance. <Total light transmittance (TT) and haze of polyimide film> Measured by the method described in JIS K7105-1981 by integrating sphere haze meter 300A manufactured by Nippon Denshoku Industries. The monomer addition amount (molar ratio of acid dianhydride and diamine respectively) when polymerizing the polyamide acid of the embodiment and the comparative example, the weight average molecular weight of the polyamide acid and the presence or absence of modification, polyimide The evaluation results of the film thickness of the film, the presence or absence of peeling from the glass plate during imidization, the peeling strength of the polyimide film from the glass plate, and the properties of the polyimide film are shown in Table 2. [Table 2]

The polyamide acid solution of Comparative Example 1 obtained from BPDA as the acid dianhydride and CHDA as the diamine was applied to the glass plate and the polyimide film during the thermal imidization after coating on the glass plate. More air bubbles are generated between them, and more than 25% of the coated area is peeled off from the glass plate. In Comparative Example 2 in which the polyamide acid of Comparative Example 1 was modified with a silane coupling agent, compared with Comparative Example 1, the adhesion to the glass plate was improved, but the peeling strength was low, and the adhesion was not full. The same is true in Comparative Example 3 in which 1 mol% of BPAF is added to BPDA as the acid dianhydride. In Comparative Example 5 and Comparative Example 6 in which reactive silicone oil was added to the monomer component, compared with Comparative Example 1, the adhesion to the glass plate was improved, but the peeling strength was low and the adhesion was insufficient . In addition, in Comparative Example 5 and Comparative Example 6, the obtained polyimide film has a high coefficient of linear thermal expansion (CTE), poor dimensional stability, and reduced transparency. In addition to CHDA, all of Examples 1 to 8 in which PAM-E having a silicone structure was used as the diamine component showed good adhesion to glass. _{Examples 1 to 7 in which the molar ratio m A} /m _B of CHDA/PAM-E was 97/3 to 99.0/0.1 all maintained the same low CTE and high transparency as Comparative Example 1. _{In Example 8 where the molar ratio m A} /m _B of CHDA/PAM-E is 95/5, the characteristics of the polyimide film have not been evaluated, but the polyimide film formed on the glass plate When visually inspected, it has the same transparency as in Examples 1-7. In addition, the composition of the polyamide acid and polyimide of Example 8 is similar to that of Example 7, so it is assumed that the same low CTE and high transparency as Example 7 are maintained. In Comparative Example 4 in which PDA was used instead of CHDA, the peel strength was equivalent to that of Examples 1 and 2, but the transparency (especially on the short-wavelength side of visible light) was greatly reduced, and coloration was visible. In Examples 1 to 8, it can be seen that with the increase in the amount of PAM-E added, the peel strength increases and the adhesion to glass tends to increase. If the polyimide film is formed on the glass plate, the ease of peeling when the polyimide film is peeled from the glass plate after the formation or installation of the components on the polyimide film as necessary is considered, then It is considered that the usage amount of the diamine containing the siloxane structure is preferably 5 mol% or less, and particularly preferably 1 mol% or less, relative to the total amount of diamine. As can be understood from the comparison of the above-mentioned examples and comparative examples, the film formation of the polyamide acid system of the present invention on the glass support and the processability during heating imidization are good, and the adhesion to the glass support is excellent. . The polyimide film obtained by the imidization of the polyimide acid of the present invention has low thermal expansion and high transparency in the high temperature range of 100-300°C, so it can be expected as a transparent substitute for glass Application of substrate materials.

Claims (4)

A method for manufacturing an electronic device, which is to coat a polyamide solution containing polyamide acid and an organic solvent on a support, and perform the removal of the aforementioned organic solvent and the imidization of the aforementioned polyamide, A polyimide film that is closely bonded and laminated on the support is formed, and after elements are formed on the polyimide film, the polyimide film on which the elements are formed is peeled from the support, and the polyimide film contains The structural unit represented by the general formula 1 and the structural unit represented by the general formula 2, and the molar number m _{A of the structural unit represented by the general formula 1 and the molar number m B} of the structural unit represented by the general formula 2 Ratio m _A /m _B is in the range of 97.0/3.0~99.9/0.1,

A of Formula 1 and B of Formula 2 are each independently a tetravalent aromatic group; R ¹ and R ^{2 of} Formula 2 are each independently a divalent hydrocarbon group; n is an integer of 1-5. According to claim 1, the method of manufacturing an electronic device, wherein the above-mentioned support is glass. The method of manufacturing an electronic device of claim 1 or 2, wherein the structural unit represented by the above general formula 2 is the structural unit represented by the formula 2B,

The method for manufacturing an electronic device according to claim 1 or 2, wherein the structural unit represented by the above general formula 1 is a structural unit represented by formula 1A, and the structural unit represented by the above general formula 2 is a structural unit represented by formula 2C,