JP2019070811A - Polyimide precursor, resin composition, and method for producing resin film - Google Patents

Abstract

To provide a flexible display that takes exceptional effect in terms of substrate warpage, a lighting test, a cloudiness test, and a heat cycle test.SOLUTION: The flexible display comprises: a polyimide film layer containing a polyimide represented by general formula (13) in the figure {where Xrepresents a C4-32 tetravalent group; R, Rand Reach independently represent a C1-20 monovalent organic group; n represents 0 or 1; and a, b and c are each an integer from 0 to 4}; and a low-temperature polysilicon TFT layer formed on the polyimide film layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of producing a polyimide precursor, a resin composition and a resin film, which are used, for example, in the production of a substrate for a flexible device.

  Generally, in applications where high heat resistance is required, a polyimide resin film is used as a resin film. A common polyimide resin is produced by solution polymerization of an aromatic carboxylic acid dianhydride and an aromatic diamine to produce a polyimide precursor, which is then thermally imidized at a high temperature, or a chemical imide using a catalyst Is a highly heat-resistant resin that is manufactured.

  The polyimide resin is an insoluble or infusible super heat-resistant resin, and has excellent properties such as thermal oxidation resistance, heat resistance, radiation resistance, low temperature resistance, chemical resistance and the like. For this reason, polyimide resins are used in a wide range of fields including electronic materials. As an application example of the polyimide resin in the electronic material field | area, an insulating coating agent, an insulating film, the protective film of a semiconductor, the electrode protective film of TFT-LCD etc. can be mentioned, for example. Recently, in place of the glass substrate conventionally used in the field of display materials, its application as a colorless and transparent flexible substrate utilizing its lightness and flexibility has been studied.

  In the case of producing a polyimide resin film as a flexible substrate, a composition containing a polyimide precursor is coated on a suitable support to form a coating, and then heat treatment is carried out to imidize the polyimide resin. Get the film. As the support, for example, glass, silicon, silicon nitride, silicon oxide, metal or the like is used. When manufacturing a laminate having a polyimide film on such a support, heat treatment at a high temperature of 250 ° C. or higher is required for drying and imidization of the polyimide precursor. This heat treatment causes residual stress in the laminate, causing serious problems such as warpage and peeling. This is because the linear thermal expansion coefficient of polyimide is larger than that of the material constituting the above-mentioned support.

As a polyimide material having a small thermal expansion coefficient, a polyimide formed from 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride and paraphenylene diamine is most well known. Although depending on film thickness and preparation conditions, it is reported that this polyimide film exhibits a very low coefficient of linear thermal expansion (Non-patent Document 1).
In addition, it is reported that a polyimide having an ester structure in a molecular chain exhibits a low linear thermal expansion coefficient because it has appropriate linearity and rigidity (Patent Document 1).

However, common polyimide resins, including the polyimides described in the above-mentioned documents, have a low light transmission in the visible light region and therefore require transparency, as they are colored brown or yellow due to high aromatic ring density It is difficult to use in the field. For example, the polyimide of the non-patent document 1 obtained from 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride and paraphenylenediamine has a yellowness (YI value) of 40 or more at a film thickness of 10 .mu.m. High and inadequate in terms of transparency.
As for the degree of yellowness of a film, for example, it is known that a polyimide using a monomer having a fluorine atom exhibits extremely low degree of yellowness (Patent Document 2).

Patent No. 4627297 specification Japanese Patent Publication No. 2010-538103 Patent No. 3079867 specification

Latest Polyimide Japan Polyimide Research Committee, edited by NTS

By the way, in order to apply a polyimide resin as a colorless and transparent flexible substrate, mechanical properties such as excellent elongation and breaking strength are also required in addition to transparency. In particular, with the recent trend that the device type of TFT is LTPS (low-temperature polysilicon TFT), a film which exhibits the above-mentioned physical properties is desired even in the thermal history more than the conventional one.
However, the physical properties of known transparent polyimides are not sufficient for use as a heat-resistant colorless transparent substrate for displays.
Furthermore, when the inventor confirmed, although the polyimide resin described in Patent Document 1 showed a low linear thermal expansion coefficient, in addition to the fact that the yellowness (YI value) of the polyimide resin film after peeling is large, It was found that there is a problem that the residual stress is high, the elongation is low, and the breaking strength is low.
With regard to yellowness, the polyimide film described in Patent Document 2 shows low yellowness in a temperature range of about 300 ° C., but it has been found that yellowness (YI value) significantly deteriorates in high temperature range of 400 ° C. The

Moreover, the polyimide which consists of a 4,4'- diamino diphenyl ether and a 4,4'- diamino diphenyl ester is disclosed as a polyimide which lowered the linear expansion coefficient (patent document 3).
However, when the present inventor confirmed, the polyimide resin described in Patent Document 3 had a very brittle film to be applied as a flexible substrate, and there was room for improvement in the degree of yellowness at high temperature.

  The present invention has been made in view of the problems described above. Therefore, an object of the present invention is to provide a polyimide resin film having low residual stress, low warpage, small yellowness (YI value), and high elongation, and a method for producing the same.

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で示される構造単位Ｌと、
下記一般式（２）：

｛式中、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｙは下記一般式（３）である。｝で示される構造単位Ｍを、
１／９９≦（構造単位Ｌのモル数／構造単位Ｍのモル数）≦９９／１
で含むことを特徴とする、ポリイミド前駆体。

｛式中、Ｒ_４〜Ｒ_５はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｅは０〜４の整数である。｝
［２］
（ａ１）下記一般式（１）：

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で示される構造単位Ｌと、
下記一般式（２）：

｛式中、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｙは下記一般式（４）である。｝で示される構造単位Ｍを、
１／９９≦（構造単位Ｌのモル数／構造単位Ｍのモル数）≦９９／１
で含むことを特徴とする、ポリイミド前駆体。

｛式中、Ｒ_６〜Ｒ_９はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｆ〜ｉは０〜４の整数である。また、Ｚは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝
［３］
前記一般式（１）におけるｎが０である、［１］または［２］に記載のポリイミド前駆体。
［４］
（ａ２）下記一般式（１０）：

で示される構造単位を有し、そして、重量平均分子量が３０，０００以上、３００，０００以下であることを特徴とするポリイミド前駆体。
｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）からなる群から選択される少なくとも１種に由来する４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
［５］
前記（ａ２）ポリイミド前駆体における、重量平均分子量１，０００未満の分子の含有量が５質量％未満である、［４］に記載のポリイミド前駆体。
［６］
一般式（１０）におけるｎが０である、［４］または［５］に記載のポリイミド前駆体。
［７］
（ａ１）下記一般式（１）：

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で示される構造単位Ｌと、
下記一般式（２）：

｛式中、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｙは下記一般式（３）、（４）および（５）からなる群から選択される少なくとも１種である。｝で示される構造単位Ｍを、
１／９９≦（構造単位Ｌのモル数／構造単位Ｍのモル数）≦９９／１
で含み、

｛式中、Ｒ_４〜Ｒ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｋは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝
前記Ｘ_１、Ｘ_２が、４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）、からなる群から選択される少なくとも１種に由来する４価の有機基であるポリイミド前駆体。
［８］
［１］〜［７］のいずれかに記載のポリイミド前駆体と、（ｂ）有機溶剤と、を含有することを特徴とする、樹脂組成物。
［９］
更に、（ｃ）界面活性剤、および（ｄ）アルコキシシラン化合物、からなる群から選択される少なくとも１種を含む、［８］に記載の樹脂組成物。
［１０］
下記一般式（１１）：

｛式中、Ｘ_１、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。Ｙは下記一般式（３）、および（４）からなる群から選択される少なくとも１種である。ｌ、ｍはそれぞれ独立に１以上の整数を表し、０．０１≦ｌ／（ｌ＋ｍ）≦０．９９を満たす。｝で表される構造単位を有することを特徴とする、ポリイミド。

｛式中、Ｒ_４〜Ｒ_９はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｉは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝
［１１］
下記一般式（１２）：

｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）からなる群から選択される少なくとも１種に由来する４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で表される構造単位を有し、伸度が１５％以上であることを特徴とする、ポリイミド。
［１２］
支持体の表面上に、［８］または［９］に記載の樹脂組成物を塗布することにより塗膜を形成する工程と、
前記支持体及び前記塗膜を加熱することにより、該塗膜に含まれるポリイミド前駆体をイミド化してポリイミド樹脂膜を形成する工程と、
前記ポリイミド樹脂膜を前記支持体から剥離する工程と、
を含むことを特徴とする、樹脂フィルムの製造方法。
［１３］
支持体の表面上に、樹脂組成物を塗布することにより塗膜を形成する工程と、
前記支持体及び前記塗膜を加熱することにより、該塗膜に含まれるポリイミド前駆体をイミド化してポリイミド樹脂膜を形成する工程と、
前記ポリイミド樹脂膜を前記支持体から剥離する工程と、を含み、
前記ポリイミド樹脂膜を前記支持体から剥離する工程に先立って、前記支持体側からレーザーを照射する工程を行う、樹脂フィルムの製造方法であって、
前記樹脂組成物が、
（ａ１）下記一般式（１）：

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で示される構造単位Ｌと、
下記一般式（２）：

｛式中、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｙは下記一般式（３）、（４）および（５）からなる群から選択される少なくとも１種である。｝で示される構造単位Ｍを、
１／９９≦（構造単位Ｌのモル数／構造単位Ｍのモル数）≦９９／１で含む、ポリイミド前駆体と、

｛式中、Ｒ_４〜Ｒ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｋは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝
（ｂ）有機溶剤と、を含有することを特徴とする、樹脂フィルムの製造方法。
［１４］
前記樹脂組成物が、更に、（ｃ）界面活性剤、および（ｄ）アルコキシシラン化合物、からなる群から選択される少なくとも１種を含む、［１３］に記載の樹脂フィルムの製造方法。
［１５］
支持体の表面上に、［８］または［９］に記載の樹脂組成物を塗布することにより塗膜を形成する工程と、
前記支持体及び前記塗膜を加熱することにより、該塗膜に含まれるポリイミド前駆体をイミド化してポリイミド樹脂膜を形成する工程と、
を含むことを特徴とする、積層体の製造方法。
［１６］
支持体の表面上に、樹脂組成物を塗布することにより塗膜を形成する工程と、
前記支持体及び前記塗膜を加熱することにより、該塗膜に含まれるポリイミド前駆体をイミド化してポリイミド樹脂膜を形成する工程と、
前記ポリイミド樹脂膜上に素子又は回路を形成する工程と、
前記素子又は回路が形成されたポリイミド樹脂膜を前記支持体から剥離する工程と、
を含む、ディスプレイ基板の製造方法であって、
前記樹脂組成物が、
（ａ１）下記一般式（１）：

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で示される構造単位Ｌと、
下記一般式（２）：

｛式中、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｙは下記一般式（３）、（４）および（５）からなる群から選択される少なくとも１種である。｝で示される構造単位Ｍを、
１／９９≦（構造単位Ｌのモル数／構造単位Ｍのモル数）≦９９／１で含む、ポリイミド前駆体と、

｛式中、Ｒ_４〜Ｒ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｋは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝
（ｂ）有機溶剤と、を含有することを特徴とする、ディスプレイ基板の製造方法。
［１７］
前記樹脂組成物が、更に、（ｃ）界面活性剤、および（ｄ）アルコキシシラン化合物、からなる群から選択される少なくとも１種を含む、［１６］に記載のディスプレイ基板の製造方法。
［１８］
下記一般式（１２）：

｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）からなる群から選択される少なくとも１種であり、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
で表されるポリイミドを含むことを特徴とする、ディスプレイ用ポリイミドフィルム。
［１９］
下記一般式（１３）：

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で表されるポリイミドを含むポリイミドフィルム層と、前記ポリイミド層上に形成された低温ポリシリコンＴＦＴ層と、を含む、フレキシブルディスプレイであって、
前記ポリイミドフィルム層は、
下記一般式（１２）：

｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）からなる群から選択される少なくとも１種であり、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
で表されるポリイミド、又は、
下記一般式（１１）：

｛式中、Ｘ_１、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。Ｙは下記一般式（３）、（４）、（５）からなる群から選択される少なくとも１種である。ｌ、ｍはそれぞれ独立に１以上の整数を表し、０．０１≦ｌ／（ｌ＋ｍ）≦０．９９を満たす。｝で表される構造単位を有するポリイミド

｛式中、Ｒ_４〜Ｒ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｋは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝から選択される少なくとも１つのポリイミドを含むことを特徴とする、フレキシブルディスプレイ。
［２０］
支持体の表面上に、樹脂組成物を塗布することにより塗膜を形成する工程と、
前記支持体及び前記塗膜を加熱することにより、該塗膜に含まれるポリイミド前駆体をイミド化してポリイミド樹脂膜を形成する工程と、
前記ポリイミド樹脂膜を前記支持体から剥離する工程と、を含み、
前記ポリイミド樹脂膜を前記支持体から剥離する工程に先立って、前記支持体側からレーザーを照射する工程を行う、樹脂フィルムの製造方法であって、
前記樹脂組成物は、
（ａ）下記一般式（１）で表されるポリイミド前駆体と、
（ｂ）有機溶剤と、
（ｃ）界面活性剤および（ｄ）アルコキシシラン化合物からなる群から選択される少なくとも１種と、
を含み、

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
前記ポリイミド樹脂膜は、
下記一般式（１２）：

｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）からなる群から選択される少なくとも１種であり、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
で表されるポリイミド、又は、
下記一般式（１１）：

｛式中、Ｘ_１、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。Ｙは下記一般式（３）、（４）からなる群から選択される少なくとも１種である。ｌ、ｍはそれぞれ独立に１以上の整数を表し、０．０１≦ｌ／（ｌ＋ｍ）≦０．９９を満たす。｝で表される構造単位を有するポリイミド

｛式中、Ｒ_４〜Ｒ_９はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｉは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝から選択される少なくとも１つのポリイミドを含むことを特徴とする、樹脂フィルムの製造方法。
［２１］
支持体の表面上に、樹脂組成物を塗布することにより塗膜を形成する工程と、
前記支持体及び前記塗膜を加熱することにより、該塗膜に含まれるポリイミド前駆体をイミド化してポリイミド樹脂膜を形成する工程と、
前記ポリイミド樹脂膜上に素子又は回路を形成する工程と、
前記素子又は回路が形成されたポリイミド樹脂膜を前記支持体から剥離する工程と、
を含む、ディスプレイ基板の製造方法であって、
前記樹脂組成物は、
（ａ）下記一般式（１）で表されるポリイミド前駆体と、
（ｂ）有機溶剤と、
（ｃ）界面活性剤および（ｄ）アルコキシシラン化合物からなる群から選択される少なくとも１種と、
を含み、

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
前記ポリイミド樹脂膜は、
下記一般式（１２）：

｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、およびビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）からなる群から選択される少なくとも１種であり、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
で表されるポリイミド、又は、
下記一般式（１１）：

｛式中、Ｘ_１、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。Ｙは下記一般式（３）、（４）、（５）からなる群から選択される少なくとも１種である。ｌ、ｍはそれぞれ独立に１以上の整数を表し、０．０１≦ｌ／（ｌ＋ｍ）≦０．９９を満たす。｝で表される構造単位を有するポリイミド

｛式中、Ｒ_４〜Ｒ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｋは０〜４の整数である。また、一般式（４）中のＺは、それぞれ独立に単結合、メチレン基、エチレン基、エーテルおよびケトンからなる群から選択される１種である。｝から選択される少なくとも１つのポリイミドを含むことを特徴とする、ディスプレイ基板の製造方法。 The present invention is as follows.
[1]
(A1) General Formula (1):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A structural unit L represented by
The following general formula (2):

In the formulae, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is the following general formula (3). The structural unit M represented by
1/99 ≦ (number of moles of structural unit L / number of moles of structural unit M) ≦ 99/1
Polyimide precursor characterized by including.

{In formula, R < ₄ > -R < ₅ > represents a C1-C20 monovalent organic group each independently. d to e are integers of 0 to 4; }
[2]
(A1) General Formula (1):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A structural unit L represented by
The following general formula (2):

In the formulae, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is the following general formula (4). The structural unit M represented by
1/99 ≦ (number of moles of structural unit L / number of moles of structural unit M) ≦ 99/1
Polyimide precursor characterized by including.

In the formulae, R _{6 to} R ₉ each independently represent a monovalent organic group having 1 to 20 carbon atoms. f-i is an integer of 0-4. In addition, Z is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. }
[3]
The polyimide precursor as described in [1] or [2] whose n in the said General formula (1) is 0.
[4]
(A2) General Formula (10):

A polyimide precursor having a structural unit represented by and having a weight average molecular weight of 30,000 or more and 300,000 or less.
Wherein X ₃ is a tetravalent group derived from at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA) and biphenyltetracarboxylic acid dianhydride (BPDA) Represent. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
[5]
The polyimide precursor according to [4], wherein the content of molecules having a weight-average molecular weight of less than 1,000 in the (a2) polyimide precursor is less than 5% by mass.
[6]
The polyimide precursor as described in [4] or [5] whose n in General formula (10) is 0.
[7]
(A1) General Formula (1):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A structural unit L represented by
The following general formula (2):

In the formulae, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5). The structural unit M represented by
1/99 ≦ (number of moles of structural unit L / number of moles of structural unit M) ≦ 99/1
Included in

{In formula, R < ₄ > -R < ₁₁ > represents a C1-C20 monovalent organic group each independently. d to k are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. }
Said X _{1 and} X ₂ are tetravalent derived from at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA), and biphenyltetracarboxylic acid dianhydride (BPDA) Polyimide precursor that is an organic group.
[8]
A resin composition comprising: the polyimide precursor according to any one of [1] to [7]; and (b) an organic solvent.
[9]
Furthermore, the resin composition as described in [8] which contains at least 1 sort (s) selected from the group which consists of (c) surfactant, and (d) alkoxysilane compound.
[10]
The following general formula (11):

[Wherein, X _{1 and} X ₂ each represent a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Y is at least one selected from the group consisting of the following general formulas (3) and (4). l and m each independently represent an integer of 1 or more, and satisfy 0.01 ≦ l / (l + m) ≦ 0.99. Polyimide characterized by having a structural unit represented by}.

In the formula, R _{4 to} R ₉ each independently represent a monovalent organic group having 1 to 20 carbon atoms. d to i are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. }
[11]
The following general formula (12):

Wherein X ₃ is a tetravalent group derived from at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA) and biphenyltetracarboxylic acid dianhydride (BPDA) Represent. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Polyimide characterized by having a structural unit represented by} and elongation being 15% or more.
[12]
Forming a coated film by applying the resin composition according to [8] or [9] on the surface of a support;
Forming the polyimide resin film by imidating the polyimide precursor contained in the coating by heating the support and the coating;
Peeling the polyimide resin film from the support;
A method of producing a resin film, comprising:
[13]
Forming a coating film by applying a resin composition on the surface of a support;
Forming the polyimide resin film by imidating the polyimide precursor contained in the coating by heating the support and the coating;
And exfoliating the polyimide resin film from the support.
It is a manufacturing method of a resin film which performs the process of irradiating a laser from the said support side prior to the process of exfoliating the said polyimide resin film from the said support,
The resin composition is
(A1) General Formula (1):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A structural unit L represented by
The following general formula (2):

In the formulae, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5). The structural unit M represented by
1/99 ≦ (number of moles of structural unit L / number of moles of structural unit M) ≦ 99/1, and a polyimide precursor,

{In formula, R < ₄ > -R < ₁₁ > represents a C1-C20 monovalent organic group each independently. d to k are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. }
(B) A method for producing a resin film, comprising: an organic solvent.
[14]
The method for producing a resin film according to [13], wherein the resin composition further comprises at least one selected from the group consisting of (c) a surfactant, and (d) an alkoxysilane compound.
[15]
Forming a coated film by applying the resin composition according to [8] or [9] on the surface of a support;
Forming the polyimide resin film by imidating the polyimide precursor contained in the coating by heating the support and the coating;
A method of producing a laminate, comprising:
[16]
Forming a coating film by applying a resin composition on the surface of a support;
Forming the polyimide resin film by imidating the polyimide precursor contained in the coating by heating the support and the coating;
Forming an element or a circuit on the polyimide resin film;
Peeling the polyimide resin film on which the element or circuit is formed from the support;
A method of manufacturing a display substrate, comprising
The resin composition is
(A1) General Formula (1):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A structural unit L represented by
The following general formula (2):

In the formulae, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5). The structural unit M represented by
1/99 ≦ (number of moles of structural unit L / number of moles of structural unit M) ≦ 99/1, and a polyimide precursor,

{In formula, R < ₄ > -R < ₁₁ > represents a C1-C20 monovalent organic group each independently. d to k are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. }
(B) A method of producing a display substrate comprising: an organic solvent.
[17]
The method for producing a display substrate according to [16], wherein the resin composition further comprises at least one selected from the group consisting of (c) surfactants, and (d) alkoxysilane compounds.
[18]
The following general formula (12):

Wherein X ₃ is at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA), and biphenyltetracarboxylic acid dianhydride (BPDA), and R ₁ and R ₂ And R ₃ each independently represents a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
The polyimide film for displays characterized by including the polyimide represented by these.
[19]
The following general formula (13):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. And a low temperature polysilicon TFT layer formed on the polyimide layer.
The polyimide film layer is
The following general formula (12):

Wherein X ₃ is at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA), and biphenyltetracarboxylic acid dianhydride (BPDA), and R ₁ and R ₂ And R ₃ each independently represents a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
Or a polyimide represented by
The following general formula (11):

[Wherein, X _{1 and} X ₂ each represent a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5). l and m each independently represent an integer of 1 or more, and satisfy 0.01 ≦ l / (l + m) ≦ 0.99. Polyimide having a structural unit represented by

{In formula, R < ₄ > -R < ₁₁ > represents a C1-C20 monovalent organic group each independently. d to k are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. A flexible display comprising at least one polyimide selected from
[20]
Forming a coating film by applying a resin composition on the surface of a support;
Forming the polyimide resin film by imidating the polyimide precursor contained in the coating by heating the support and the coating;
And exfoliating the polyimide resin film from the support.
It is a manufacturing method of a resin film which performs the process of irradiating a laser from the said support side prior to the process of exfoliating the said polyimide resin film from the said support,
The resin composition is
(A) A polyimide precursor represented by the following general formula (1),
(B) organic solvent,
(C) at least one selected from the group consisting of surfactants and (d) alkoxysilane compounds,
Including

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
The polyimide resin film is
The following general formula (12):

Wherein X ₃ is at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA), and biphenyltetracarboxylic acid dianhydride (BPDA), and R ₁ and R ₂ And R ₃ each independently represents a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
Or a polyimide represented by
The following general formula (11):

[Wherein, X _{1 and} X ₂ each represent a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Y is at least one selected from the group consisting of the following general formulas (3) and (4). l and m each independently represent an integer of 1 or more, and satisfy 0.01 ≦ l / (l + m) ≦ 0.99. Polyimide having a structural unit represented by

In the formula, R _{4 to} R ₉ each independently represent a monovalent organic group having 1 to 20 carbon atoms. d to i are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. A method of producing a resin film, comprising at least one polyimide selected from
[21]
Forming a coating film by applying a resin composition on the surface of a support;
Forming the polyimide resin film by imidating the polyimide precursor contained in the coating by heating the support and the coating;
Forming an element or a circuit on the polyimide resin film;
Peeling the polyimide resin film on which the element or circuit is formed from the support;
A method of manufacturing a display substrate, comprising
The resin composition is
(A) A polyimide precursor represented by the following general formula (1),
(B) organic solvent,
(C) at least one selected from the group consisting of surfactants and (d) alkoxysilane compounds,
Including

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
The polyimide resin film is
The following general formula (12):

Wherein X ₃ is at least one selected from the group consisting of 4,4′-oxydiphthalic acid dianhydride (ODPA), and biphenyltetracarboxylic acid dianhydride (BPDA), and R ₁ and R ₂ And R ₃ each independently represents a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
Or a polyimide represented by
The following general formula (11):

[Wherein, X _{1 and} X ₂ each represent a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Y is at least one selected from the group consisting of the following general formulas (3), (4) and (5). l and m each independently represent an integer of 1 or more, and satisfy 0.01 ≦ l / (l + m) ≦ 0.99. Polyimide having a structural unit represented by

{In formula, R < ₄ > -R < ₁₁ > represents a C1-C20 monovalent organic group each independently. d to k are integers of 0 to 4; Further, Z in the general formula (4) is each independently one selected from the group consisting of a single bond, a methylene group, an ethylene group, an ether and a ketone. A method of manufacturing a display substrate, comprising at least one polyimide selected from

  The polyimide film obtained from the polyimide precursor and the resin composition according to the present invention has low residual stress, low warpage, small yellowness (YI value), and high elongation.

The figure which shows the structure of the organic electroluminescent board | substrate produced by the Example and the comparative example.

  Hereinafter, exemplary embodiments of the present invention (hereinafter abbreviated as “embodiments”) will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the invention. In addition, characteristic values described in the present disclosure are values measured by methods understood by those skilled in the art to be equivalent to the method described in the section of [Example] unless otherwise specified. Intended.

<Resin composition>
The resin composition provided by one aspect of the present invention contains (a) a polyimide precursor, and (b) an organic solvent.
Hereinafter, each component will be described in order.

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で示される構造単位Ｌと、
下記一般式（２）：

｛式中、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｙは下記一般式（３）、（４）および（５）からなる群から選択される少なくとも１種である｝で示される構造単位Ｍとを
１／９９≦（構造単位Ｌのモル数／構造単位Ｍのモル数）≦９９／１で含むことを特徴とする、ポリイミド前駆体である。

｛式中、Ｒ_４〜Ｒ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ〜ｋは０〜４の整数である。｝
本実施の第一の態様のポリイミド前駆体は、ポリイミドフィルムとしたときに残留応力が低く、反りが少なく、黄色度（ＹＩ値）が小さく、伸度が高い。また、本実施の第一の態様のポリイミド前駆体は、ポリイミドフィルムとしたときに、高温領域での黄色度（ＹＩ値）が小さい。
ここで、Ｒ_１〜Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基であれば限定されない。このような有機基として、メチル基、エチル基、プロピル基などのアルキル基、トリフルオロメチル基などのハロゲン含有基、メトキシ基、エトキシ基などのアルコキシ基、などが挙げられる。この中で、高温領域でのＹＩの観点から、メチル基が好ましい。
ここで、ａ、ｂ、ｃ、ｄは０〜４の整数であれば限定されない。この中で、ＹＩ、残留応力の観点から０〜２の整数が好ましく、高温領域でのＹＩの観点から、０が特に好ましい。
ここで、ｎは０または１である。この中で、高温領域でのＹＩの観点から、０が好ましい。 [Polyimide precursor]
The polyimide precursor as the first aspect of the present embodiment is
(A1) General Formula (1):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A structural unit L represented by
The following general formula (2):

In the formulae, X ₂ represents a tetravalent group having 4 to 32 carbon atoms. Y is at least one member selected from the group consisting of the following general formulas (3), (4) and (5) and 1/99 ≦ (the number of moles of the structural unit L / structure) It is a polyimide precursor characterized by including by the mole number of unit M) <= 99/1.

{In formula, R < ₄ > -R < ₁₁ > represents a C1-C20 monovalent organic group each independently. d to k are integers of 0 to 4; }
The polyimide precursor of the first embodiment of the present embodiment has low residual stress, low warpage, low yellowness (YI value), and high elongation when formed into a polyimide film. In addition, when the polyimide precursor of the first aspect of the present embodiment is a polyimide film, the degree of yellowness (YI value) in a high temperature region is small.
Here, R _{1 to} R ₃ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. As such an organic group, an alkyl group such as a methyl group, an ethyl group or a propyl group, a halogen-containing group such as a trifluoromethyl group, an alkoxy group such as a methoxy group or an ethoxy group, and the like can be mentioned. Among them, methyl group is preferable from the viewpoint of YI in a high temperature region.
Here, a, b, c and d are not limited as long as they are integers of 0 to 4. Among them, the integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.
Here, n is 0 or 1. Among these, 0 is preferable from the viewpoint of YI in a high temperature region.

The lower limit of the molar ratio of structural unit L to structural unit M (number of moles of structural unit L / number of moles of structural unit M) may be 5/95, 10/90, 20/80, 30 It may be / 70 or 40/60. The upper limit of the molar ratio of structural unit L to structural unit M (number of moles of structural unit L / number of moles of structural unit M) may be 95/5, 90/10, 80/20, 70/30. But it may be 60/40.
X ₁ and X ₂ each independently represent a tetravalent group having 4 to 32 carbon atoms, and may be the same or different. The following tetravalent organic group derived from tetracarboxylic acid dianhydride is illustrated.
Specific examples of the tetracarboxylic acid dianhydride include aromatic tetracarboxylic acid dianhydride having 8 to 36 carbon atoms, aliphatic tetracarboxylic acid dianhydride having 6 to 36 carbon atoms, and carbon atoms Can be exemplified by compounds selected from alicyclic tetracarboxylic acid dianhydrides of 6 to 36. Among them, aromatic tetracarboxylic dianhydrides having 8 to 36 carbon atoms are preferable from the viewpoint of yellowness in a high temperature range. The number of carbons referred to herein includes the number of carbons contained in the carboxyl group.

  More specifically, examples of the aromatic tetracarboxylic acid dianhydride having 8 to 36 carbon atoms include 4,4 ′-(hexafluoroisopropylidene) diphthalic anhydride (hereinafter also referred to as 6FDA), 2,5-Dioxotetrahydro-3-furanyl) -3-methyl-cyclohexene-1,2 dicarboxylic anhydride, pyromellitic dianhydride (hereinafter also referred to as PMDA), 1,2,3,4-benzene Tetracarboxylic acid dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid dianhydride, 2,2 ′, 3,3′-benzophenonetetracarboxylic acid dianhydride, 3,3 ′, 4, 4'-biphenyltetracarboxylic acid dianhydride (hereinafter also referred to as BPDA), 3,3 ', 4,4'-diphenyl sulfone tetracarboxylic acid dianhydride, 2,2', 3,3'-bif Niltetracarboxylic acid dianhydride, methylene-4,4'-diphthalic acid dianhydride, 1,1-ethylidene-4,4'-diphthalic acid dianhydride, 2,2-propylidene-4,4'-diphthalic acid Acid dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4 ' -Diphthalic acid dianhydride, 1,5-pentamethylene-4,4'-diphthalic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride (hereinafter also referred to as ODPA), p-phenylene bis (trimellitic acid) Anhydride (hereinafter referred to as TAHQ) thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride, 1,3-bis (3,4-dicarboxyphenyl) Benzene dianhydride, 1,3-bis 3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,3-bis [2- (3,4-dicarboxyphenyl)- 2-propyl] benzene dianhydride, 1,4-bis [2- (3,4-dicarboxyphenyl) -2-propyl] benzene dianhydride, bis [3- (3,4-dicarboxyphenoxy) phenyl Methane dianhydride, bis [4- (3,4-dicarboxyphenoxy) phenyl] methane dianhydride, 2,2-bis [3- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, bis (3,4-dicarboxyphenoxy) dimethylsilane dianhydride, 1,3-bis (3,4-) Dicarboxyphenyl) -1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid Anhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride And 1,2,7,8-phenanthrene tetracarboxylic acid dianhydride etc. can be illustrated.

Examples of aliphatic tetracarboxylic acid dianhydrides having 6 to 50 carbon atoms include ethylene tetracarboxylic acid dianhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, etc .;
As the alicyclic tetracarboxylic acid dianhydride having 6 to 36 carbon atoms, for example, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, cyclohexane-1,2,3 3,4-tetracarboxylic acid dianhydride, cyclohexane-1,2,4,5-tetracarboxylic acid dianhydride (hereinafter referred to as CHDA), 3,3 ′, 4,4′-bicyclohexyltetracarboxylic acid Dianhydride, carbonyl-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, methylene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1, 2-ethylene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, 1,1-ethylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, , 2-Propylidene-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, thio-4 4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, sulfonyl-4,4'-bis (cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo [2,2,2] oct -7-ene-2,3,5,6-tetracarboxylic acid dianhydride, rel- [1S, 5R, 6R] -3-oxabicyclo [3,2,1] octane-2,4-dione-6 -Spiro-3 '-(tetrahydrofuran-2', 5'-dione), 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic acid Anhydride, ethylene glycol Bis - (3,4-dicarboxylic acid anhydride) ether, etc. may be mentioned, respectively.

  From the viewpoint of CTE, chemical resistance, and balance of Tg and yellowness in the high temperature region, PMDA, BPDA, TAHQ, ODPA are preferable, and BPDA, TAHQ are more preferable.

The polyimide precursor in the embodiment may be made into a polyamideimide precursor by using a dicarboxylic acid in addition to the above-mentioned tetracarboxylic acid dianhydride as long as the performance thereof is not impaired. By using such a precursor, various properties such as improvement in mechanical elongation, improvement in glass transition temperature, and reduction in yellowness can be adjusted in the obtained film. Such dicarboxylic acids include dicarboxylic acids having an aromatic ring and alicyclic dicarboxylic acids. In particular, at least one compound selected from the group consisting of aromatic dicarboxylic acids having 8 to 36 carbon atoms and alicyclic dicarboxylic acids having 6 to 34 carbon atoms is preferable. The number of carbons referred to herein includes the number of carbons contained in the carboxyl group.
Among these, dicarboxylic acids having an aromatic ring are preferred.

Specifically, for example, isophthalic acid, terephthalic acid, 4,4'-biphenyldicarboxylic acid, 3,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3 -Naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 4,4'-sulfonylbisbenzoic acid, 3,4'-sulfonylbisbenzoic acid, 3,3'-sulfonylbisbenzoic acid 4,4,4'-oxybisbenzoic acid, 3,4'-oxybisbenzoic acid, 3,3'-oxybisbenzoic acid, 2,2-bis (4-carboxyphenyl) propane, 2,2-bis (3-carboxy) Phenyl) propane, 2,2'-dimethyl-4,4'-biphenyl dicarboxylic acid, 3,3'-dimethyl-4,4'-biphenyl dicarboxylic acid, 2,2'-di 4,3'-biphenyldicarboxylic acid, 9,9-bis (4- (4-carboxyphenoxy) phenyl) fluorene, 9,9-bis (4- (3-carboxyphenoxy) phenyl) fluorene, 4,4 '-Bis (4-carboxyphenoxy) biphenyl, 4,4'-bis (3-carboxyphenoxy) biphenyl, 3,4'-bis (4-carboxyphenoxy) biphenyl, 3,4'-bis (3-carboxyphenoxy 4) biphenyl, 3,3′-bis (4-carboxyphenoxy) biphenyl, 3,3′-bis (3-carboxyphenoxy) biphenyl, 4,4′-bis (4-carboxyphenoxy) -p-terphenyl, 4 4,4'-Bis (4-carboxyphenoxy) -m-terphenyl, 3,4'-bis (4-carboxyphenoxy) -p-turf , 3,3'-bis (4-carboxyphenoxy) -p-terphenyl, 3,4'-bis (4-carboxyphenoxy) -m-terphenyl, 3,3'-bis (4-carboxyphenoxy) -M-terphenyl, 4,4'-bis (3-carboxyphenoxy) -p-terphenyl, 4,4'-bis (3-carboxyphenoxy) -m-terphenyl, 3,4'-bis (3) -Carboxyphenoxy) -p-terphenyl, 3,3'-bis (3-carboxyphenoxy) -p-terphenyl, 3,4'-bis (3-carboxyphenoxy) -m-terphenyl, 3,3 ' -Bis (3-carboxyphenoxy) -m-terphenyl, 1,1-cyclobutanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4,4 ' Benzophenone dicarboxylic acid, 1,3-phenylene diacetic acid, 1,4-phenylene diacetic acid and the like; and 5-amino isophthalic acid derivative according to and WO 2005/068535 pamphlet can be mentioned. When these dicarboxylic acids are actually copolymerized into a polymer, they may be used in the form of acid chlorides derived from thionyl chloride and the like, active esters and the like.

10,000-300,000 are preferable and, as for the weight average molecular weight (Mw) of the polyimide precursor in this Embodiment, 30,000-200,000 are especially preferable. When the weight average molecular weight is greater than 10,000, mechanical properties such as elongation and breaking strength are excellent, residual stress is low, and YI is low. When the weight average molecular weight is less than 300,000, the weight average molecular weight can be easily controlled at the time of synthesis of the polyamic acid, a resin composition having an appropriate viscosity can be obtained, and the coatability of the resin composition is improved. In the present disclosure, the weight average molecular weight is a value determined as a standard polystyrene equivalent value using gel permeation chromatography (hereinafter also referred to as GPC).
In the polyimide precursor in the present embodiment, the content of molecules having a molecular weight of less than 1,000 is preferably less than 5% by mass, further preferably less than 1% by mass, with respect to the total amount of the polyimide precursor. preferable. The polyimide film formed from the resin composition obtained using such a polyimide precursor becomes a thing with a low residual stress, and it is preferable from a viewpoint that Haze of the inorganic film formed on this polyimide film becomes low.
The content of molecules having a molecular weight of less than 1,000 based on the total amount of the polyimide precursor can be calculated from the peak area obtained by performing GPC measurement using a solution in which the polyimide precursor is dissolved.

（式中、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。）
Ｒ_１、Ｒ_２としては、メチル基、エチル基、プロピル基などのアルキル基、トリフルオロメチル基などのハロゲン含有基、メトキシ基、エトキシ基などのアルコキシ基、などが挙げられる。この中で、高温領域でのＹＩの観点から、メチル基が好ましい。
ここで、ａ、ｂは０〜４の整数であれば限定されない。この中で、ＹＩ、残留応力の観点から０〜２の整数が好ましく、高温領域でのＹＩの観点から、０が特に好ましい。
より具体的には、ｎが０の場合は、４−アミノフェニル−４−アミノベンゾエート（ＡＰＡＢ）、２−メチル−４−アミノフェニル−４−アミノベンゾエート（ＡＴＡＢ）、４−アミノフェニル−３−アミノベンゾエート（４，３−ＡＰＡＢ）などを例示することができる。
ｎが１の場合は、［４−（４−アミノベンゾイル）オキシフェニル］４−アミノベンゾエートなどを例示することができる。
本実施の形態における一般式（３）で表される構造単位に用いられるジアミンとしては、下記一般式（７）で表されるジアミンを例示することができる。

（式中、Ｒ_４、Ｒ_５はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｄ、ｅは０〜４の整数である。）
ここで、Ｒ_４、Ｒ_５はそれぞれ独立に炭素数１〜２０の１価の有機基であれば限定されない。このような有機基として、メチル基、エチル基、プロピル基などのアルキル基、トリフルオロメチル基などのハロゲン含有基、メトキシ基、エトキシ基などのアルコキシ基、などが挙げられる。この中で、高温領域でのＹＩの観点から、メチル基が好ましい。
ここで、ｃ、ｄは０〜４の整数であれば限定されない。この中で、ＹＩ、残留応力の観点から０〜２の整数が好ましく、高温領域でのＹＩの観点から、０が特に好ましい。
より具体的には、４，４’−ジアミノジフェニルスルホン、３，３’−ジアミノジフェニルスルホンを例示することができる。
本実施の形態における一般式（４）で表される構造単位に用いられるジアミンとしては、下記一般式（８）で表されるジアミンを例示することができる。

ここで、Ｒ_６及びＲ_７はそれぞれ独立に炭素数１〜２０の１価の有機基であれば限定されない。このような有機基として、例えば、メチル基、エチル基、プロピル基等のアルキル基；トリフルオロメチル基等のハロゲン含有基；メトキシ基、エトキシ基等のアルコキシ基；等が挙げられる。この中で、高温領域でのＹＩの観点から、メチル基が好ましい。
Ｒ_８とＲ_９はそれぞれ独立に炭素数１〜２０の１価の有機基、水酸基、又はハロゲン原子であれば限定されない。上記の有機基としては、例えば、メチル基、エチル基、プロピル基等のアルキル基；トリフルオロメチル基等のハロゲン含有基；メトキシ基、エトキシ基等のアルコキシ基；等が挙げられる。ハロゲン原子としては、例えば、フッ素原子、塩素原子、臭素原子、ヨウ素原子等が挙げられる。
ｆ、ｇ、ｈ、及びｉはそれぞれ独立に０〜４の整数であれば限定されない。この中で、ＹＩ、残留応力の観点から０〜２の整数が好ましく、高温領域でのＹＩの観点から、０が特に好ましい。
Ｚは単結合、メチレン基、エチレン基、エーテル、ケトンなどが例示できる。この中で、高温領域でのＹＩの観点から、単結合がより好ましい。
より具体的には、９，９−ビス（アミノフェニル）フルオレン、９，９−ビス（４−アミノ−３−メチルフェニル）フルオレン、９，９−ビス（４−アミノ−３−フルオロフェニル）フルオレン、９，９−ビス（４−ヒドロキシ−３−アミノフェニル）フルオレン、９，９−ビス［４−（４−アミノフェノキシ）フェニル］フルオレン等を例示することができ、これらのうちから選択される１種以上を使用することが好ましい。 As a diamine used for the structural unit represented by General formula (1) in this Embodiment, the diamine represented by following General formula (6) can be illustrated.

(Wherein, R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. N represents 0 or 1. and a, b and c are integers of 0 to 4) Is)
Examples of R ₁ and R ₂ include alkyl groups such as methyl, ethyl and propyl; halogen-containing groups such as trifluoromethyl; and alkoxy groups such as methoxy and ethoxy. Among them, methyl group is preferable from the viewpoint of YI in a high temperature region.
Here, a and b are not limited as long as they are integers of 0 to 4. Among them, the integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.
More specifically, when n is 0, 4-aminophenyl-4-aminobenzoate (APAB), 2-methyl-4-aminophenyl-4-aminobenzoate (ATAB), 4-aminophenyl-3- Amino benzoate (4,3-APAB) etc. can be illustrated.
When n is 1, [4- (4-aminobenzoyl) oxyphenyl] 4-aminobenzoate etc. can be illustrated.
As a diamine used for the structural unit represented by General formula (3) in this Embodiment, the diamine represented by following General formula (7) can be illustrated.

(Wherein, R _{4 and} R ₅ each independently represent a monovalent organic group having 1 to 20 carbon atoms _. D and e are integers of 0 to 4).
Here, R _{4 and} R ₅ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. As such an organic group, an alkyl group such as a methyl group, an ethyl group or a propyl group, a halogen-containing group such as a trifluoromethyl group, an alkoxy group such as a methoxy group or an ethoxy group, and the like can be mentioned. Among them, methyl group is preferable from the viewpoint of YI in a high temperature region.
Here, c and d are not limited as long as they are integers of 0 to 4. Among them, the integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.
More specifically, 4,4'-diaminodiphenyl sulfone and 3,3'-diaminodiphenyl sulfone can be exemplified.
As a diamine used for the structural unit represented by General formula (4) in this Embodiment, the diamine represented by following General formula (8) can be illustrated.

Here, R ₆ and R ₇ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl and propyl; halogen-containing groups such as trifluoromethyl; and alkoxy groups such as methoxy and ethoxy. Among them, methyl group is preferable from the viewpoint of YI in a high temperature region.
R ₈ and R ₉ are not limited as long as they are each independently a C 1-20 monovalent organic group, a hydroxyl group or a halogen atom. Examples of the organic group include alkyl groups such as methyl, ethyl and propyl; halogen-containing groups such as trifluoromethyl; and alkoxy groups such as methoxy and ethoxy. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example.
There are no limitations on f, g, h, and i as long as they are each independently an integer of 0 to 4. Among them, the integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.
Z can be exemplified by a single bond, a methylene group, an ethylene group, an ether, a ketone and the like. Among these, a single bond is more preferable from the viewpoint of YI in a high temperature region.
More specifically, 9,9-bis (aminophenyl) fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene, 9,9-bis (4-amino-3-fluorophenyl) fluorene And 9,9-bis (4-hydroxy-3-aminophenyl) fluorene, 9,9-bis [4- (4-aminophenoxy) phenyl] fluorene and the like can be exemplified, and it is selected from these It is preferable to use one or more.

ここで、Ｒ_１０及びＲ_１１はそれぞれ独立に炭素数１〜２０の１価の有機基であれば限定されない。このような有機基として、例えば、メチル基、エチル基、プロピル基等のアルキル基；トリフルオロメチル基等のハロゲン含有基；メトキシ基、エトキシ基等のアルコキシ基；等が挙げられる。この中で、高温領域でのＹＩの観点から、メチル基が好ましい。
また、ｊ、ｋはそれぞれ独立に０〜４の整数であれば限定されない。この中で、ＹＩ、残留応力の観点から０〜２の整数が好ましく、高温領域でのＹＩの観点から、０が特に好ましい。
より具体的には、２、２’−ビス（トリフルオロメチル）ベンジジンなどを例示することができる。
本実施の第一の態様のポリイミド前駆体から形成されるポリイミドフィルムは、残留応力が低く、反りが少なく、高温領域での黄色度（ＹＩ値）が小さく、伸度が高い。 As a diamine used for the structural unit represented by General formula (5) in this Embodiment, the diamine represented by following General formula (9) can be illustrated.

Here, R ₁₀ and R ₁₁ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. Examples of such organic groups include alkyl groups such as methyl, ethyl and propyl; halogen-containing groups such as trifluoromethyl; and alkoxy groups such as methoxy and ethoxy. Among them, methyl group is preferable from the viewpoint of YI in a high temperature region.
In addition, j and k are not limited as long as they are each independently an integer of 0 to 4. Among them, the integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.
More specifically, 2, 2'-bis (trifluoromethyl) benzidine etc. can be illustrated.
The polyimide film formed from the polyimide precursor of the first embodiment of the present embodiment has low residual stress, low warpage, low yellowness (YI value) in a high temperature region, and high elongation.

で示される構造単位を有し、そして、重量平均分子量が３０，０００以上、３００，０００以下であるポリイミド前駆体を提供することができる。
｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、ビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）、及び４，４’−ビフェニルビス（トリメリット酸モノエステル酸無水物）（ＴＡＨＱ）、から選択される少なくとも１種に由来する４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
ここでＸ_３はＯＤＰＡ，ＢＰＤＡ、ＴＡＨＱから選択される少なくとも１種に由来する４価の有機基であれば限定されないが、ＣＴＥおよびＴｇの観点から、ＢＰＤＡ、ＴＡＨＱが好ましい。
ここで、Ｒ_１〜Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基であれば限定されない。このような有機基として、メチル基、エチル基、プロピル基などのアルキル基、トリフルオロメチル基などのハロゲン含有基、メトキシ基、エトキシ基などのアルコキシ基、などが挙げられる。この中で、高温領域でのＹＩの観点から、メチル基が好ましい。
ここで、ａ、ｂ、ｃ、ｄは０〜４の整数であれば限定されない。この中で、ＹＩ、残留応力の観点から０〜２の整数が好ましく、高温領域でのＹＩの観点から、０が特に好ましい。
ここで、ｎは０または１である。この中で、高温領域でのＹＩの観点から、０が好ましい。 As a second aspect of the present embodiment,
(A2) General Formula (10):

It is possible to provide a polyimide precursor having a structural unit represented by and having a weight average molecular weight of 30,000 or more and 300,000 or less.
Wherein X ₃ is 4,4′-oxydiphthalic acid dianhydride (ODPA), biphenyltetracarboxylic acid dianhydride (BPDA), and 4,4′-biphenyl bis (trimellitic acid monoester acid anhydride) (TAHQ) represents a tetravalent group derived from at least one selected from R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
Here, X ₃ is not limited as long as it is a tetravalent organic group derived from at least one selected from ODPA, BPDA, and TAHQ, but BPDA and TAHQ are preferable from the viewpoint of CTE and Tg.
Here, R _{1 to} R ₃ are not limited as long as they are each independently a monovalent organic group having 1 to 20 carbon atoms. As such an organic group, an alkyl group such as a methyl group, an ethyl group or a propyl group, a halogen-containing group such as a trifluoromethyl group, an alkoxy group such as a methoxy group or an ethoxy group, and the like can be mentioned. Among them, methyl group is preferable from the viewpoint of YI in a high temperature region.
Here, a, b, c and d are not limited as long as they are integers of 0 to 4. Among them, the integer of 0 to 2 is preferable from the viewpoint of YI and residual stress, and 0 is particularly preferable from the viewpoint of YI in a high temperature region.
Here, n is 0 or 1. Among these, 0 is preferable from the viewpoint of YI in a high temperature region.

As a diamine for the structure represented by above-mentioned General formula (10), the diamine used by above-mentioned General formula (6) can be used.
The weight average molecular weight (Mw) of the polyimide precursor in the second embodiment is 30,000 to 300,000. When the weight average molecular weight is more than 30,000, mechanical properties such as elongation and breaking strength are excellent, residual stress is low, and YI is low. When the weight average molecular weight is less than 300,000, the weight average molecular weight can be easily controlled at the time of synthesis of the polyamic acid, a resin composition having an appropriate viscosity can be obtained, and the coatability of the resin composition is improved. Among these, the weight average molecular weight (Mw) is more preferably 35,000 or more and 250,000 or less, and particularly preferably 40000 or more and 230000 or less.

In the polyimide precursor in the second embodiment of the present invention, the content of molecules having a molecular weight of less than 1,000 is preferably less than 5% by mass, and less than 1% by mass with respect to the total amount of the polyimide precursor. Is more preferred. The polyimide film formed from the resin composition obtained using such a polyimide precursor becomes a thing with a low residual stress, and it is preferable from a viewpoint that Haze of the inorganic film formed on this polyimide film becomes low.
The content of molecules having a molecular weight of less than 1,000 based on the total amount of the polyimide precursor can be calculated from the peak area obtained by performing GPC measurement using a solution in which the polyimide precursor is dissolved.
The polyimide precursor of the second aspect of the present embodiment is excellent in storage stability and excellent in coatability. In addition, the polyimide film formed from the polyimide precursor of the second embodiment of the present embodiment has low residual stress, low warpage, small yellowness (YI value), high elongation, and high breaking strength.

In the polyimide precursor in the first aspect and the second aspect, the diamine represented by the general formulas (6) to (9) described above, as long as the elongation, strength, stress, yellowness and the like are not impaired. Besides, other diamines can be used.
As other diamines, for example, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 4,4′- Diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3) -Aminophenoxy) benzene, bis [4- (4-aminophenoxy) phenyl Sulfone, 4,4-bis (4-aminophenoxy) biphenyl, 4,4-bis (3-aminophenoxy) biphenyl, bis [4- (4-aminophenoxy) phenyl] ether, bis [4- (3-amino) Phenoxy) phenyl] ether, 1,4-bis (4-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 9,10-bis (4-aminophenyl) anthracene, 2,2-bis (4-aminophenyl) propane, 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl) propane, 2,2-bis [4- ( 4-aminophenoxy) phenyl) hexafluoropropane, 1,4-bis (3-aminopropyldimethylsilyl) benzene, etc. Can, it is preferable to use one or more selected from these.
20 mol% or less is preferable and, as for content of the said other diamine in all the diamine, 10 mol% or less is especially preferable.

[Production of Polyimide Precursor]
The polyimide precursor (polyamic acid) of the present invention comprises tetracarboxylic acid dianhydride, a diamine (for example, APAB) used for the structural unit represented by the above general formula (1), and the above general formula (2) It can synthesize | combine by carrying out the polycondensation reaction with the diamine (for example, 4, 4'-DAS) used for the structural unit represented by these. The reaction is preferably carried out in a suitable solvent. Specifically, for example, after dissolving predetermined amounts of APAB and 4,4'-DAS in a solvent, a predetermined amount of tetracarboxylic acid dianhydride is added to the obtained diamine solution and stirred. Be
In the diamine component, the molar ratio of the diamine used for the structural unit represented by the general formula (1) to the diamine used for the structural unit represented by the general formula (2) is 99/1 to 1/99 For example, it is not limited. If the diamine used for the structural unit represented by the general formula (2) in the diamine component is 1 mol% or more, the yellowness tends to be good, and it is used for the structural unit represented by the general formula (1) If the diamine to be added is 1 mol% or more, the warp after forming the inorganic film on the obtained polyimide film tends to be good. The molar ratio of the diamine used for the structural unit represented by the general formula (1) to the diamine used for the structural unit represented by the general formula (2) is preferably 95/5 to 50/50, 90/10 50 to 50 is more preferable. The molar ratio of the diamine used for the structural unit represented by the general formula (1) to the diamine used for the structural unit represented by the general formula (2) may be 80/20 to 50/50, 70 / 30 to 50/50 may be sufficient. It is preferable to make the molar ratio of the diamine used for the structural unit represented by General formula (1) more than the molar ratio with the diamine used for the structural unit represented by General formula (2).
In addition, the polyimide precursor of the second embodiment of the present embodiment includes tetracarboxylic acid dianhydride (for example, TAHQ) and diamine (for example, APAB) used for the structural unit represented by the above-mentioned general formula (6). It can be synthesized by polycondensation reaction. The reaction is preferably carried out in a suitable solvent. Specifically, for example, a method of dissolving a predetermined amount of APAB in a solvent, adding a predetermined amount of TAHQ to the obtained diamine solution, and stirring it may be mentioned.

When synthesizing the polyimide precursor, the ratio (molar ratio) of the tetracarboxylic acid dianhydride component to the diamine component is the coefficient of thermal expansion, residual stress, elongation, and yellowness (hereinafter referred to as YI) of the obtained resin film. Tetracarboxylic acid dianhydride: diamine = 100: 90 to 100: 110 (based on 1 mol part of tetracarboxylic acid dianhydride) from 0.90 to 1.1. It is preferable to set it as the range of 10 mol part, and it is further more preferable to set it as the range of 100: 95-100: 105 (0.95 to 1.05 mol part of diamine with respect to 1 mol part of acid dianhydride).
In this embodiment, when synthesizing a polyamic acid which is a preferable polyimide precursor, the molecular weight is controlled by adjusting the ratio of the tetracarboxylic acid dianhydride component to the diamine component, and by adding an end capping agent. It is possible. The molecular weight of the polyamic acid can be increased as the ratio of the acid dianhydride component to the diamine component is closer to 1: 1 and as the amount of the end capping agent used is smaller.
It is recommended to use high purity products as the tetracarboxylic acid dianhydride component and the diamine component. The purity thereof is preferably 98% by mass or more, more preferably 99% by mass or more, and still more preferably 99.5% by mass or more. When a plurality of acid dianhydride components or diamine components are used in combination, it is sufficient if the acid dianhydride component or diamine component as a whole has the above purity, but all types of acid dianhydrides used It is preferable that the component and the diamine component each have the above-mentioned purity.

式中、Ｒ_１２＝メチル基で表されるエクアミドＭ１００（商品名：出光興産社製）、及び、Ｒ_１２＝ｎ−ブチル基で表されるエクアミドＢ１００（商品名：出光興産社製）等のアミド系溶媒；
γ−ブチロラクトン、γ−バレロラクトン等のラクトン系溶媒；
ヘキサメチルホスホリックアミド、ヘキサメチルホスフィントリアミド等の含りん系アミド系溶媒；
ジメチルスルホン、ジメチルスルホキシド、スルホラン等の含硫黄系溶媒；
シクロヘキサノン、メチルシクロヘキサノン等のケトン系溶媒；
ピコリン、ピリジン等の３級アミン系溶媒；
酢酸（２−メトキシ−１−メチルエチル）等のエステル系溶媒
等が：
前記フェノ−ル系溶媒として、例えば、フェノ−ル、ｏ−クレゾ−ル、ｍ−クレゾ−ル、ｐ−クレゾ−ル、２，３−キシレノ−ル、２，４−キシレノ−ル、２，５−キシレノ−ル、２，６−キシレノ−ル、３，４−キシレノ−ル、３，５−キシレノ−ル等が：
前記エ−テル及びグリコ−ル系溶媒として、例えば、１，２−ジメトキシエタン、ビス（２−メトキシエチル）エ−テル、１，２−ビス（２−メトキシエトキシ）エタン、ビス［２− （２−メトキシエトキシ）エチル］エ−テル、テトラヒドロフラン、１，４−ジオキサン等が、
それぞれ挙げられる。 The solvent for the reaction is not particularly limited as long as it is a solvent capable of dissolving the tetracarboxylic acid dianhydride component and the diamine component, and the generated polyamic acid and obtaining a polymer of high molecular weight. Specific examples of such solvents include, for example, aprotic solvents, phenol solvents, ethers, glycol solvents and the like. Examples of these are
As the aprotic solvent, for example, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methylcaprolactam, 1,3-dimethyl Imidazolidinone, tetramethyl urea, the following general formula (13):

In the formula, Equamide M100 represented by R ₁₂ = methyl group (trade name: manufactured by Idemitsu Kosan Co., Ltd.), and Equamide B 100 represented by R ₁₂ = n-butyl group (trade name: manufactured by Idemitsu Kosan Co., Ltd.) Amide solvents;
Lactone solvents such as γ-butyrolactone and γ-valerolactone;
Phosphorus-containing amide solvents such as hexamethylphosphoric amide and hexamethylphosphine triamide;
Sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, sulfolane and the like;
Ketone solvents such as cyclohexanone and methyl cyclohexanone;
Tertiary amine solvents such as picolin and pyridine;
Ester solvents such as acetic acid (2-methoxy-1-methylethyl) etc.
Examples of the phenol solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, and 2, 5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol etc.
As the ether and glycol solvents, for example, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- 2-Methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,4-dioxane etc.
Each one is listed.

60-300 degreeC is preferable, as for the boiling point in the normal pressure of the solvent used for the synthesis | combination of a polyamic acid, 140-280 degreeC is more preferable, and its 170-270 degreeC is especially preferable. When the boiling point of the solvent is higher than 300 ° C., a drying step is required for a long time. On the other hand, if the boiling point of the solvent is lower than 60 ° C., roughening on the surface of the resin film, mixing of air bubbles into the resin film, etc. may occur during the drying step, and a uniform film may not be obtained.
Thus, using a solvent having a boiling point of preferably 170 to 270 ° C., and more preferably a vapor pressure of 250 Pa or less at 20 ° C. is preferable from the viewpoint of solubility and edge repelling during coating. More specifically, it is preferable to use one or more selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, and a compound represented by the above general formula (11).
The water content in the solvent is preferably 3,000 ppm by mass or less.
These solvents may be used alone or in combination of two or more.

The (a) polyimide precursor in this embodiment preferably has a content of molecules having a molecular weight of less than 1,000 is less than 5% by mass.
The presence of the molecule having a molecular weight of less than 1,000 in the polyimide precursor (a) is considered to be due to the water content of the solvent used in the synthesis. That is, it is considered that the acid anhydride group of some of the acid dianhydride monomers is hydrolyzed by water to be a carboxyl group, and remains in a low molecular state without high molecular weight formation. Therefore, the water content of the solvent used for the above-mentioned polymerization reaction should be as small as possible. The water content of the solvent is preferably 3,000 ppm by mass or less, and more preferably 1,000 ppm by mass or less.

  The water content of the solvent is the grade of solvent used (dehydration grade, general purpose grade, etc.), solvent container (bottle, 18 L can, canister can etc.), storage condition of solvent (presence or absence of rare gas inclusion etc.), from opening to use It may be considered that the time period of use (whether used immediately after opening or used after aging after opening etc.) is involved. In addition, it is considered that the noble gas substitution of the reactor before synthesis, the presence or absence of the rare gas circulation during synthesis, and the like are also involved. Therefore, at the time of synthesis of the (a) polyimide precursor, a high purity product is used as a raw material, a solvent with a small amount of water is used, and measures are taken so that water from the environment does not enter the system before and during the reaction. Is recommended.

When dissolving each monomer component in a solvent, it may be heated if necessary.
The reaction temperature at the time of (a) polyimide precursor synthesis is preferably 0 ° C to 120 ° C, more preferably 40 ° C to 100 ° C, and still more preferably 60 to 100 ° C. By conducting the polymerization reaction at this temperature, a polyimide precursor having a high degree of polymerization can be obtained. The polymerization time is preferably 1 to 100 hours, and more preferably 2 to 10 hours. By setting the polymerization time to 1 hour or more, a polyimide precursor having a uniform polymerization degree can be obtained, and by setting the polymerization time to 100 hours or less, a polyimide precursor having a high polymerization degree can be obtained.

In a preferred aspect of the present embodiment, (a1) polyimide precursor and (a2) polyimide precursor have the following characteristics.
(A) A solution obtained by dissolving a polyimide precursor in a solvent (for example, N-methyl-2-pyrrolidone) is applied to the surface of a support, and then the solution is subjected to a nitrogen atmosphere (for example, having an oxygen concentration of 2,000 ppm or less) In a resin obtained by imidizing the polyimide precursor by heating (for example, 1 hour) at 300 to 550 ° C. (eg, 430 ° C.) in nitrogen, the yellowness at a film thickness of 10 μm is 30 or less.
(A) A solution obtained by dissolving a polyimide precursor in a solvent (for example, N-methyl-2-pyrrolidone) is applied to the surface of a support, and then the solution is subjected to a nitrogen atmosphere (for example, having an oxygen concentration of 2,000 ppm or less) In a resin obtained by imidizing the polyimide precursor by heating (for example, 1 hour) at 300 to 550 ° C. (for example, 430 ° C.) in nitrogen, the residual stress is 25 MPa or less.

｛一般式（１４）中、複数存在するＲ_１３は、それぞれ独立に、水素原子、炭素数１〜２０の一価の脂肪族炭化水素、又は一価の芳香族基であり、
Ｘ_４は炭素数４〜３２の四価の有機基であり、
Ｙは炭素数４〜３２の二価の有機基である。ただし、
前記一般式（１）および前記一般式（６）に相当する構造単位を除く。｝で表される構造を有するポリイミド前駆体を更に含有してもよい。 The polyimide precursor according to the present embodiment may, if necessary, have the following general formula (14), as long as the desired performance of the present invention is not impaired:

In the general formula (14), a plurality of R _{13 's} each independently represent a hydrogen atom, a monovalent aliphatic hydrocarbon having 1 to 20 carbon atoms, or a monovalent aromatic group,
X ₄ is a tetravalent organic group having 4 to 32 carbon atoms,
Y is a C4-C32 divalent organic group. However,
The structural units corresponding to the general formula (1) and the general formula (6) are excluded. You may further contain the polyimide precursor which has a structure represented by}.

In the general formula (14), R ₁₃ is preferably a hydrogen atom. Further, X ₃ is preferably a tetravalent aromatic group from the viewpoint of heat resistance, reduction of YI value, and total light transmittance. Y is preferably a divalent aromatic group or an alicyclic group from the viewpoint of heat resistance, reduction in YI value, and total light transmittance.

  The proportion by mass of the polyimide precursor having the structural unit represented by the general formula (14) in the (a) polyimide precursor according to the present embodiment is 80% by mass or less with respect to all of the (a) polyimide precursor. It is more preferable that it is 70 mass% or less from the viewpoint of a reduction in oxygen dependence of YI value and total light transmittance.

In a preferable aspect of the present embodiment, a part of the (a1) polyimide precursor and the (a2) polyimide precursor may be imidized. The imidation ratio in this case is preferably 80% or less, more preferably 50% or less. This partial imidization is obtained by heating and dehydrating ring closure of the (a) polyimide precursor described above. This heating can be performed preferably at a temperature of 120 to 200 ° C., more preferably at a temperature of 150 to 180 ° C., preferably for 15 minutes to 20 hours, more preferably for 30 minutes to 10 hours.
Further, N, N-dimethylformamide dimethyl acetal or N, N-dimethylformamide diethyl acetal is added to the polyamic acid obtained by the above reaction and heated to esterify part or all of the carboxylic acid, By using as a (a) polyimide precursor in this Embodiment, the resin composition in which the viscosity stability at the time of room temperature storage was improved can also be obtained. In addition, these ester-modified polyamic acids are obtained by sequentially reacting the above-mentioned acid dianhydride component with one equivalent of a monohydric alcohol with respect to an acid anhydride group, and a dehydration condensation agent such as thionyl chloride or dicyclohexylcarbodiimide. It can also be obtained by a method of condensation reaction with a diamine component.

  The proportion of the (a) polyimide precursor (preferably polyamic acid) in the resin composition of the present embodiment is preferably 3 to 50% by mass, more preferably 5 to 40% by mass, from the viewpoint of film formation. 30% by weight is particularly preferred.

<Resin composition>
Another aspect of the present invention provides a resin composition containing (a) a polyimide precursor and (b) an organic solvent as described above. The resin composition is typically a varnish.

[(B) Organic solvent]
The (b) organic solvent in the present embodiment is not particularly limited as long as it can dissolve the (a) polyimide precursor described above and other components which are optionally used. As such a (b) organic solvent, those described above as the solvent which can be used at the time of the synthesis of the (a) polyimide precursor can be used. Preferred organic solvents are also as described above. The (b) organic solvent in the resin composition of the present embodiment may be the same as or different from the solvent used for the synthesis of the (a) polyimide precursor.
The organic solvent (b) is preferably used in such an amount that the solid content concentration of the resin composition is 3 to 50% by mass. Moreover, it is preferable to add after adjusting the structure and quantity of (b) organic solvent so that the viscosity (25 degreeC) of a resin composition may be 500 mPa * s-100,000 mPa * s.

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝ [Other ingredients]
The resin composition of the present embodiment may further contain (c) a surfactant, (d) an alkoxysilane compound and the like in addition to the components (a) and (b).
The resin composition according to the present embodiment comprises (a) a polyimide precursor, (b) an organic solvent, and (c) at least one selected from the group consisting of a surfactant and (d) an alkoxysilane compound. including.
The skeleton of the polyimide precursor is not limited to the skeleton described above in the first aspect and the second aspect. That is, the skeleton of the polyimide precursor is not particularly limited as long as it is a skeleton represented by the following general formula (1).

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }

((C) surfactant)
The coatability of the resin composition can be improved by adding a surfactant to the resin composition of the present embodiment. Specifically, the generation of streaks in the coated film can be prevented.
Examples of such surfactants include silicone surfactants, fluorine surfactants, and nonionic surfactants other than these. Examples of these are
As silicone type surfactant, for example, organosiloxane polymers KF-640, 642, 643, KP 341, X-70-092, X-70-093, (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), SH-28 PA , SH-190, SH-193, SZ-6032, SF-8428, DC-57, DC-190 (trade names, manufactured by Toray Dow Corning Silicone Co., Ltd.), SILWET L-77, L-7001, FZ -2105, FZ-2120, FZ-2154, FZ-2164, FZ-2166, L-7604 (above, trade name, manufactured by Nippon Unicar Co., Ltd.), DBE-814, DBE-224, DBE-621, CMS-626, CMS-222, KF-352A, KF-354L, KF-355A, KF-6020, DBE-821, DBE- 712 (Gelest), BYK-307, BYK-310, BYK-378, BYK-333 (above, trade name, manufactured by BIC Chemie Japan), Granol (trade name, manufactured by Kyoeisha Chemical Co., Ltd.), etc .;
As fluorinated surfactants, for example, Megafac F171, F173, R-08 (Dainippon Ink & Chemicals, Inc., trade name), Florard FC 4430, FC 4432 (Sumitomo 3M Ltd., trade name), etc .;
As nonionic surfactants other than these, polyoxyethylene uralyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether etc. are mentioned, for example.

Among these surfactants, silicone surfactants and fluorine surfactants are preferable from the viewpoint of coating property (sludge suppression) of the resin composition, and YI value and total light transmittance according to oxygen concentration at the curing step are preferable. From the viewpoint of the influence on the rate, silicone surfactants are preferred.
When using surfactant (c), 0.001-5 mass parts are preferable with respect to 100 mass parts of (a) polyimide precursors in a resin composition, and the compounding quantity is 0.01-3 mass parts. Is more preferred.

(D) Alkoxysilane Compound In order to make the resin film obtained from the resin composition according to the present embodiment exhibit sufficient adhesion to a support in the manufacturing process of a flexible device etc., the resin composition The substance may contain the alkoxysilane compound in an amount of 0.01 to 20% by mass with respect to 100% by mass of the (a) polyimide precursor. When the content of the alkoxysilane compound is 0.01% by mass or more based on 100% by mass of the polyimide precursor, good adhesion to the support can be obtained. Further, the content of the alkoxysilane compound is preferably 20% by mass or less from the viewpoint of storage stability of the resin composition. The content of the alkoxysilane compound is more preferably 0.02 to 15% by mass, further preferably 0.05 to 10% by mass, based on 100 parts by mass of the polyimide precursor. Particularly preferred is 8% by mass.
By using an alkoxysilane compound as an additive of the resin composition according to the present embodiment, in addition to the above-mentioned improvement of the adhesion, the coatability (suppression of uneven streaks) of the resin composition can be further improved and obtained. It is possible to reduce the oxygen concentration dependency during curing of the YI value of the cured film.

  As the alkoxysilane compound, for example, 3-ureidopropyltriethoxysilane, bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltripropoxysilane, γ-aminopropyltributoxysilane, γ-aminoethyltriethoxysilane, γ-aminoethyltripropoxysilane, γ-aminoethyltributoxysilane, γ-aminobutyltriethoxysilane, γ- Aminobutyltrimethoxysilane, γ-aminobutyltripropoxysilane, γ-aminobutyltributoxysilane, phenylsilanetriol, trimethoxyphenylsilane, trimethoxy (p-tolyl) silane, diphenylsilanediol And dimethoxydiphenylsilane, diethoxydiphenylsilane, dimethoxydi-p-tolylsilane, triphenylsilanol, and alkoxysilane compounds represented by each of the following structures, and the like, and one or more selected from these can be used. Is preferred.

The method for producing the resin composition in the present embodiment is not particularly limited. For example, the following method can be used.
When the solvent used when synthesizing the polyimide precursor (a) and the organic solvent (b) are the same, the synthesized polyimide precursor solution can be used as it is as a resin composition. In addition, if necessary, at least one of (b) an organic solvent and other components is added to the polyimide precursor in a temperature range of room temperature (25 ° C.) to 80 ° C., and after stirring and mixing, the resin composition You may use as a thing. For this stirring and mixing, appropriate devices such as a three-one motor (manufactured by Shinto Kagaku Co., Ltd.) equipped with stirring blades, a rotation and revolution mixer, and the like can be used. Moreover, you may add a heat | fever of 40-100 degreeC as needed.

  On the other hand, when the solvent used when synthesizing (a) the polyimide precursor is different from (b) the organic solvent, the solvent in the synthesized polyimide precursor solution is, for example, reprecipitated, evaporated, etc. (A) After removing the polyimide precursor by an appropriate method and isolating the polyimide precursor, add (b) the organic solvent and, if necessary, other components in a temperature range of room temperature to 80 ° C., and stir and mix. The resin composition may be prepared by

  After preparing the resin composition as described above, the composition solution is heated, for example, at 130 to 200 ° C., for example, for 5 minutes to 2 hours to dehydrate part of the polyimide precursor to such an extent that the polymer does not precipitate. It may be imidized. Here, the imidization rate can be controlled by controlling the heating temperature and the heating time. By partially imidizing the polyimide precursor, the viscosity stability of the resin composition during storage at room temperature can be improved. The imidization ratio is preferably in the range of 5% to 70% from the viewpoint of balance between the solubility of the polyimide precursor in the resin composition solution and the storage stability of the solution.

The resin composition according to the present embodiment preferably has a water content of 3,000 mass ppm or less.
The water content of the resin composition is more preferably 1,000 mass ppm or less, and still more preferably 500 mass ppm or less, from the viewpoint of viscosity stability when the resin composition is stored.

The solution viscosity of the resin composition according to the present embodiment is preferably 500 to 200,000 mPa · s at 25 ° C., more preferably 2,000 to 100,000 mPa · s, and 3,000 to 30,000 mPa · s. Is particularly preferred. The solution viscosity can be measured using an E-type viscometer (VISCONICEHD, manufactured by Toki Sangyo Co., Ltd.). If the solution viscosity is less than 300 mPa · s, coating during film formation is difficult, and if it is more than 200,000 mPa · s, there may be a problem that stirring during synthesis becomes difficult.
(A) When synthesizing a polyimide precursor, even if the solution has a high viscosity, it is possible to obtain a resin composition with a manageable viscosity by adding a solvent after the completion of the reaction and stirring. is there.

The resin composition of the present embodiment has the following characteristics in a preferred embodiment.
After the resin composition is applied to the surface of a support to form a coating, the coating is heated at 300 ° C. to 550 ° C. under a nitrogen atmosphere (for example, in nitrogen with an oxygen concentration of 2,000 ppm or less). The resin film obtained by imidizing the polyimide precursor contained in the coating film has a yellowness YI of 30 or less at a film thickness of 10 μm.

  After the resin composition is applied to the surface of a support to form a coating, the coating is heated at 300 ° C. to 550 ° C. under a nitrogen atmosphere (for example, in nitrogen with an oxygen concentration of 2,000 ppm or less). The resin film obtained by imidizing the polyimide precursor contained in the coating film has a residual stress of 25 MPa or less.

The resin composition according to the present embodiment can be suitably used, for example, to form a transparent substrate of a display device such as a liquid crystal display, an organic electroluminescence display, a field emission display, and an electronic paper. Specifically, it can be used to form a thin film transistor (TFT) substrate, a color filter substrate, a transparent conductive film (ITO, indium thin oxide) substrate, and the like.
The resin precursor of the present embodiment can form a polyimide film having a residual stress of 25 MPa or less, and thus can be easily applied to a display manufacturing process in which a TFT element device is provided on a colorless and transparent polyimide substrate.

<Resin film>
Another aspect of the present invention provides a resin film formed from the aforementioned resin precursor.
Yet another aspect of the present invention provides a method of producing a resin film from the above-described resin composition.
The resin film in the present embodiment is
Forming a coating film by applying the above-described resin composition on the surface of a support (coating step);
Heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film (heating step);
Peeling the polyimide resin film from the support (peeling step);
It is characterized by including.

Here, the support is not particularly limited as long as it has heat resistance at the heating temperature of the subsequent step and the peelability is good. For example, glass (eg, alkali-free glass) substrate;
Silicon wafer;
Resin substrates of PET (polyethylene terephthalate), OPP (oriented polypropylene), polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamide imide, polyether imide, polyether ether ketone, polyether sulfone, polyphenylene sulfone, polyphenylene sulfide, etc. ;
A metal substrate of stainless steel, alumina, copper, nickel or the like is used.

  When forming a film-like polyimide molded body, for example, a glass substrate, a silicon wafer or the like is preferable, and when forming a film-like or sheet-like polyimide molded body, for example, PET (polyethylene terephthalate), OPP A support made of (oriented polypropylene) or the like is preferred.

Coating methods include, for example, doctor blade knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, coating method such as bar coater, spin coating, spray coating, dip coating, etc .; screen printing A printing technique typified by gravure printing can be applied.
Although the application thickness should be suitably adjusted according to the thickness of the desired resin film and the content of the polyimide precursor in a resin composition, Preferably it is about 1-1,000 micrometers. Although the application step is sufficient at room temperature, the resin composition may be heated in the range of 40 to 80 ° C. for the purpose of lowering the viscosity to improve the workability.

  Following the coating step, a drying step may be performed, or the drying step may be omitted and the process may proceed directly to the next heating step. This drying step is performed for the purpose of removing the organic solvent. When the drying step is performed, appropriate devices such as a hot plate, a box dryer, a conveyor dryer and the like can be used, for example. The drying step is preferably performed at 80 to 200 ° C., and more preferably at 100 to 150 ° C. The implementation time of the drying step is preferably 1 minute to 10 hours, and more preferably 3 minutes to 1 hour.

As described above, the coating film containing the polyimide precursor is formed on the support.
Subsequently, a heating step is performed. The heating step is a step of removing the organic solvent remaining in the coating film in the above-described drying step and advancing the imidization reaction of the polyimide precursor in the coating film to obtain a film made of polyimide.
This heating step can be performed using an apparatus such as, for example, an inert gas oven, a hot plate, a box dryer, a conveyor dryer, and the like. This step may be performed simultaneously with the drying step or both steps may be performed sequentially.

The heating step may be carried out under an air atmosphere, but it is recommended to carry out under an inert gas atmosphere from the viewpoint of safety and the transparency and YI value of the resulting polyimide film. Examples of the inert gas include nitrogen, argon and the like.
Although heating temperature may be suitably set according to the kind of organic solvent, 250 ° C-550 ° C is preferred, and 300-450 ° C is more preferred. If the temperature is 250 ° C. or higher, imidization is sufficient, and if the temperature is 550 ° C. or lower, there is no disadvantage such as a decrease in transparency of the obtained polyimide film and a deterioration in heat resistance. The heating time is preferably about 0.5 to 3 hours.
In the present embodiment, the oxygen concentration in the ambient atmosphere in the above heating step is preferably 2,000 mass ppm or less, more preferably 100 mass ppm or less, from the viewpoint of the transparency of the polyimide film to be obtained and the YI value. The mass ppm or less is more preferable. By heating in an atmosphere having an oxygen concentration of 2,000 ppm by mass or less, the YI value of the obtained polyimide film can be made to be 30 or less.

Depending on the use and purpose of the polyimide resin film, after the heating step, a peeling step of peeling the resin film from the support is required. The peeling step is preferably performed after cooling the resin film on the support to about room temperature to about 50 ° C.
As this peeling process, the aspect of following (1)-(4) is mentioned, for example.

(1) By preparing a structure including a polyimide resin film / support by the above method, a laser is irradiated from the support side of the structure to ablate the interface between the support and the polyimide resin film. , A method of peeling polyimide resin. The type of laser includes a solid (YAG) laser, a gas (UV excimer) laser and the like. It is preferable to use a spectrum such as a wavelength of 308 nm (see, for example, JP-A-2007-512568, JP-A-2012-511173, etc.).
(2) A method of forming a release layer on a support before applying the resin composition to the support, and thereafter obtaining a structure including a polyimide resin film / release layer / support and peeling the polyimide resin film . As a peeling layer, a method using Parylene (registered trademark, manufactured by Japan Parylene Joint Company), tungsten oxide; (Refer Unexamined-Japanese-Patent No. 2010-67957, Unexamined-Japanese-Patent No. 2013-179306 etc.).
This method (2) may be used in combination with the laser irradiation of the above (1).

(3) A method for obtaining a polyimide resin film by etching a metal with an etchant after obtaining a structure including a polyimide resin film / support using a metal substrate which can be etched as a support. As the metal, for example, copper (as a specific example, electrolytic copper foil “DFF” manufactured by Mitsui Mining & Smelting Co., Ltd.), aluminum or the like can be used. As an etchant, ferric chloride or the like can be used for copper, and dilute hydrochloric acid or the like can be used for aluminum.
(4) After obtaining a structure including a polyimide resin film / support by the above method, an adhesive film is attached to the surface of the polyimide resin film, and the adhesive film / polyimide resin film is separated from the support, and then the adhesive film Of separating polyimide resin film from water.

Among these peeling methods, the method (1) or (2) is appropriate from the viewpoint of the refractive index difference between the front and back of the polyimide resin film to be obtained, the YI value, and the elongation. Method (1) is more appropriate in terms of refractive index difference.
In addition, in the method (3), when copper is used as a support, the YI value of the obtained polyimide resin film tends to be large and the elongation tends to be small. This is considered to be the effect of copper ions.

  Although the thickness of the resin film obtained by said method is not specifically limited, It is preferable that it is the range of 1-200 micrometers, More preferably, it is 5-100 micrometers.

The resin film according to this embodiment can have a yellowness YI of 30 or less at a film thickness of 10 μm. In addition, the residual stress can be 25 MPa or less. In particular, the yellowness YI at a film thickness of 10 μm can be 30 or less, and the residual stress can be 25 MPa or less. Such properties can be obtained, for example, by using the resin precursor of the present disclosure under a nitrogen atmosphere (for example, in nitrogen with an oxygen concentration of 2,000 ppm or less), preferably 300.degree. C. to 550.degree. C., more preferably 350.degree. Can be realized well.
The resin film according to the present embodiment can further have a tensile elongation of 15% or more. The tensile elongation of the resin film can be further 20% or more, in particular 30% or more. This tensile elongation can be measured using a commercially available tensile tester using a 10 μm thick resin film as a sample.

｛式中、Ｘ_１、Ｘ_２は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。Ｙは前記一般式（３）、（４）および（５）からなる群から選択される少なくとも１種である。ｌ、ｍはそれぞれ独立に１以上の整数を表し、０．０１≦ｌ／（ｌ＋ｍ）≦０．９９を満たす。｝で表される構造単位を有する。
ｌ／（ｌ＋ｍ）の下限は、０．０５でもよく、０．１０でもよく、０．２０でもよく、０．３０でもよく、０．４０でもよい。
ｌ／（ｌ＋ｍ）の上限は、０．９５でもよく、０．９０でもよく、０．８０でもよく、０．７０でもよく、０．６０でもよい。
前述のように、好ましくは、残留応力が２５ＭＰａ以下であり、ＹＩが３０以下であり、ガラス転移温度が４００℃以上であり、伸度が１５％以上であり、そして破断強度が２５０ＭＰａ以上である。 The resin film concerning this Embodiment is a film which consists of a polyimide by which the polyimide precursor contained in the above-mentioned resin composition was heat-imidized. Therefore, the following general formula (11):

[Wherein, X _{1 and} X ₂ each represent a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Y is at least one selected from the group consisting of the general formulas (3), (4) and (5). l and m each independently represent an integer of 1 or more, and satisfy 0.01 ≦ l / (l + m) ≦ 0.99. Having a structural unit represented by
The lower limit of l / (l + m) may be 0.05, 0.10, 0.20, 0.30 or 0.40.
The upper limit of l / (l + m) may be 0.95, 0.90, 0.80, 0.70 or 0.60.
As mentioned above, preferably, the residual stress is 25 MPa or less, YI is 30 or less, the glass transition temperature is 400 ° C. or more, the elongation is 15% or more, and the breaking strength is 250 MPa or more .

｛式中、Ｘ_３は４，４’−オキシジフタル酸二無水物（ＯＤＰＡ）、ビフェニルテトラカルボン酸二無水物（ＢＰＤＡ）、及び４，４’−ビフェニルビス（トリメリット酸モノエステル酸無水物）（ＴＡＨＱ）、から選択される少なくとも１種に由来する４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝で表される構造単位を有し、伸度が１５％以上である、樹脂フィルムであり、好ましくは残留応力が２５ＭＰａ以下であり、ＹＩが３０以下であり、ガラス転移温度が４００℃以上であり、そして破断強度が２５０ＭＰａ以上である。 Moreover, as a 2nd aspect, it is a film which the polyimide precursor contained in the above-mentioned resin composition consists of the polyimide by which heat | fever imidation was carried out. Therefore, the following general formula (12):

Wherein X ₃ is 4,4′-oxydiphthalic acid dianhydride (ODPA), biphenyltetracarboxylic acid dianhydride (BPDA), and 4,4′-biphenyl bis (trimellitic acid monoester acid anhydride) (TAHQ) represents a tetravalent group derived from at least one selected from R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A resin film having a structural unit represented by} and having an elongation of 15% or more, preferably a residual stress of 25 MPa or less, a YI of 30 or less, and a glass transition temperature of 400 ° C. or more And the breaking strength is 250 MPa or more.

<Laminate>
Another aspect of the present invention provides a laminate comprising a support and a polyimide resin film formed from the above-described resin composition on the surface of the support.
Moreover, another aspect of this invention provides the manufacturing method of the said laminated body.
The laminate in the present embodiment is
Forming a coating film by applying the above-described resin composition on the surface of a support (coating step);
Heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film (heating step);
Can be obtained by the method for producing a laminate.
The method for producing a laminate described above can be carried out, for example, in the same manner as the method for producing a resin film described above, except that the peeling step is not performed.

This laminate can be suitably used, for example, in the manufacture of flexible devices.
Further detailed description is as follows.
In the case of forming a flexible display, a glass substrate is used as a support, a flexible substrate is formed thereon, and a TFT or the like is further formed thereon. The process of forming a TFT or the like on a flexible substrate is typically performed at a wide temperature range of 150 to 650 ° C. However, in order to realize the actually desired performance, TFT-IGZO (InGaZnO) oxide semiconductor or TFT (a-Si-TFT, poly) using an inorganic material at high temperature around 250 ° C. to 450 ° C. It is necessary to form (Si-TFT).
On the other hand, various physical properties (in particular, the yellowness and elongation) of the polyimide film tend to decrease due to these heat histories, and when the temperature exceeds 400 ° C., the yellowness and elongation particularly decrease. However, the polyimide film obtained from the polyimide precursor according to the present invention has a very low decrease in yellowness and elongation even in a high temperature region of 400 ° C. or higher, and can be favorably used in the region.

｛式中、Ｘ_１は炭素数４〜３２の４価の基を表す。Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立に炭素数１〜２０の１価の有機基を表す。ｎは０または１を表す。そしてａとｂとｃは０〜４の整数である。｝
当該積層体の製造方法としては前述の支持体と、該支持体の表面上に前述の樹脂組成物から形成されたポリイミド樹脂膜とを含む、積層体を製造した後に、アモルファスＳｉ層を形成し、４００〜４５０℃で０．５〜３時間程度脱水素アニールを行った後に、エキシマレーザー等で結晶化することによりＬＴＰＳ層を形成することができる。その後、レーザー剥離などでガラスとポリイミドフィルムを剥離することによって、上記積層体を得ることができる。 Furthermore, in the present embodiment, a laminate including a polyimide film layer containing a polyimide represented by the following general formula (13) and an LTPS (low temperature polysilicon TFT) layer can be provided.

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. }
As a method of producing the laminate, an amorphous Si layer is formed after producing a laminate including the above-described support and a polyimide resin film formed from the above-described resin composition on the surface of the support. After dehydrogenation annealing is performed at 400 to 450 ° C. for about 0.5 to 3 hours, the LTPS layer can be formed by crystallization using an excimer laser or the like. Then, the said laminated body can be obtained by peeling glass and a polyimide film by laser peeling etc.

The laminate including the polyimide film layer containing polyimide represented by the general formula (13) and the LTPS (low temperature polysilicon TFT) layer has less peeling and swelling after the heat cycle test and less substrate warpage.
Further, if residual stress generated in the flexible substrate and the polyimide resin film is high, the laminate comprising the both expands in the high temperature TFT process and then shrinks at room temperature cooling when warping and breakage of the glass substrate, glass of the flexible substrate Problems such as peeling from the substrate may occur. In general, since the thermal expansion coefficient of a glass substrate is smaller than that of a resin, residual stress occurs between the glass substrate and the flexible substrate. Since the resin film concerning this embodiment can make the residual stress which arises with a glass substrate 25 micrometers or less as above-mentioned, it can be used conveniently for formation of a flexible display.

  Furthermore, in the polyimide film according to the present embodiment, the yellowness YI at a film thickness of 10 μm can be 30 or less, and the tensile elongation can be 15% or more. By this, the resin film concerning this embodiment is excellent in the breaking strength at the time of handling a flexible substrate, and can therefore improve the yield at the time of manufacturing a flexible display.

In another embodiment, the yellowness at a film thickness of 10 microns after heating at 400 ° C. or higher is 20 or less, and the absorbance at 308 nm at a film thickness of 0.1 micron is 0.6 to 2.0. It is possible to provide a polyimide film which has an elongation of 15% or more.
By setting YI to 20 or less, a flexible substrate can be manufactured without degrading the image quality when used as a display.
More preferably, it is 18 or less, and particularly preferably 16 or less.
By setting the absorbance at 308 nm to 0.6 to 2.0 and the elongation to 15% or more when the film thickness is 0.1 micron, for example, the polyimide film can be easily peeled off from the glass substrate by a laser. From the viewpoint of suppressing ash after laser peeling, 0.6 or more and 1.5 or less and elongation 20% or more are preferable, for example, from the viewpoint not to degrade the performance of the organic EL element 20% or more is especially preferable.
The upper limit of the elongation is not particularly limited, but may be 80% or less, 70% or less, 60% or less, 50% or less, or 40% or less.
In addition, a polyimide film may burn with a laser beam at the time of laser peeling, and the embers are ash.

Thus, another aspect of the present invention provides a display substrate.
Yet another aspect of the present invention provides a method of manufacturing the display substrate.
The method of manufacturing a display substrate in the present embodiment is
Forming a coating film by applying the above-described resin composition on the surface of a support (coating step);
Heating the support and the coating film to imidize the polyimide precursor contained in the coating film to form a polyimide resin film (heating step);
Forming an element or circuit on the polyimide resin film (element / circuit forming process);
And peeling the polyimide resin film on which the element or circuit is formed from the support (peeling step).

In the above method, the coating step, the heating step, and the peeling step can be performed in the same manner as the method for producing the resin film described above.
The device / circuit formation process can be performed by methods known to those skilled in the art.

  The resin film according to the present embodiment satisfying the above-mentioned physical properties is suitably used for applications in which the use is restricted by the yellow possessed by existing polyimide films, in particular for colorless transparent substrates for flexible displays, protective films for color filters, etc. Ru. Furthermore, for example, a protective film, a light-diffusing sheet and a coating film in a TFT-LCD, etc. (for example, an interlayer of a TFT-LCD, a gate insulating film, a liquid crystal alignment film, etc.) It can also be used in fields where colorless transparency and low birefringence are required, such as, etc. When the polyimide according to the present embodiment is applied as a liquid crystal alignment film, it becomes possible to manufacture a TFT-LCD having a high aperture ratio and a high contrast ratio.

  The polyimide precursor according to the present embodiment, and the resin film and the laminate produced using the resin precursor can be applied as, for example, a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, etc. In manufacture, it can be suitably used particularly as a substrate. Here, as a flexible device which can apply the resin film and laminate concerning this embodiment, a flexible display, a flexible solar cell, a flexible touch panel electrode substrate, a flexible lighting, a flexible battery etc. can be mentioned, for example.

Hereinafter, the present invention will be described in more detail based on examples, but these are described for the purpose of explanation, and the scope of the present invention is not limited to the following examples.
Various evaluations in Examples and Comparative Examples were performed as follows.

<Measurement of weight average molecular weight>
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) under the following conditions.
As a solvent, N, N-dimethylformamide (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph, lithium bromide monohydrate of 24.8 mmol / L (manufactured by Wako Pure Chemical Industries, purity 99.2 just before measurement). 5%) and 63.2 mmol / L of phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph) were added and dissolved. The calibration curve for calculating the weight average molecular weight was prepared using standard polystyrene (manufactured by Tosoh Corporation).

Column: Shodex KD-806M (made by Showa Denko)
Flow rate: 1.0 mL / min Column temperature: 40 ° C.
Pump: PU-2080 Plus (manufactured by JASCO)
Detector: RI-2031 Plus (RI: differential refractometer, manufactured by JASCO) and UV-2075 Plus (UV-VIS: ultraviolet-visible spectrophotometer, manufactured by JASCO)

<Evaluation of the content of molecules having a molecular weight of less than 1,000 (content of low molecular weight monomers)>
The content of the molecule having a molecular weight of less than 1,000 in the resin is the ratio of the peak area occupied by the component having a molecular weight of less than 1,000 to the peak area of the entire molecular weight distribution using the GPC measurement results obtained above Calculated as).

<Evaluation of water content>
The moisture content of the synthetic solvent and the resin composition (varnish) was measured using a Karl-Fisher moisture measuring device (trace moisture measuring device AQ-300, manufactured by Hiranuma Sangyo Co., Ltd.).

<Evaluation of viscosity stability of resin composition>
Regarding the resin composition prepared in each of the examples and the comparative examples,
Perform viscosity measurement at 23 ° C as a sample after preparation, leaving a sample left to stand at room temperature for 3 days after preparation;
After that, a sample left to stand at room temperature for 2 weeks was used as a sample after 2 weeks, and viscosity measurement at 23 ° C. was performed again. These viscosity measurements were performed using a temperature controlled viscometer (TV-22 manufactured by Toki Sangyo Co., Ltd.).
Using the above measured values, the rate of change in viscosity for two weeks at room temperature was calculated according to the following formula.
Room temperature two week viscosity change rate (%) = [(viscosity of sample after two weeks)-(viscosity of sample after preparation)] / (viscosity of sample after preparation) × 100
The viscosity change rate at room temperature for 2 weeks was evaluated based on the following criteria.
◎: The viscosity change rate is 5% or less (storage stability "excellent")
○: The viscosity change rate is more than 5 and 10% or less (storage stability "good")
X: Viscosity change rate is over 10% (storage stability "defect")

<Evaluation of varnish coatability>
The resin composition prepared in each of the examples and comparative examples was applied on an alkali-free glass substrate (size 37 × 47 mm, thickness 0.7 mm) using a bar coater to a cured film thickness of 15 μm. Thereafter, it was prebaked at 140 ° C. for 60 minutes.
The coatability of the varnish was evaluated by measuring the level difference on the coating film surface using a level difference meter (manufactured by Tencor, model name P-15).
:: The surface level difference is 0.1 um or less (applicability "excellent")
○: The surface level difference is more than 0.1 and 0.5 um or less (applicability "good")
X: The surface level difference is over 0.5 um (applicability "defect")

<Evaluation of residual stress>
Each resin composition was applied by a spin coater on a 6-inch silicon wafer with a thickness of 625 μm ± 25 μm, for which “the amount of warpage” was previously measured, and prebaked at 100 ° C. for 7 minutes. Thereafter, using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B), the oxygen concentration in the chamber is adjusted to 10 mass ppm or less, and heat curing treatment at 430 ° C. for 1 hour ( A curing process was performed to obtain a silicon wafer having a polyimide resin film having a thickness of 10 μm after curing.
The amount of warpage of the wafer was measured using a residual stress measuring apparatus (manufactured by Tencor, model name FLX-2320) to evaluate the residual stress generated between the silicon wafer and the resin film.
◎: Residual stress is more than -5-15 MPa or less (Evaluation of residual stress "excellent")
○: Residual stress is more than 15 and 25 MPa or less (Evaluation of residual stress "Good")
X: Residual stress is over 25 MPa (Evaluation of residual stress "Defect")

<Curve evaluation of polyimide resin film on which inorganic film is formed>
The resin composition prepared in each of the examples and comparative examples is spin-coated on a 6-inch silicon wafer substrate provided with an aluminum deposition layer on the surface so that the film thickness becomes 10 μm after curing, and 100 ° C. for 7 minutes Prebaked. After that, using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B), the oxygen concentration in the chamber is adjusted to 10 mass ppm or less, and heat curing treatment is performed at 430 ° C. for 1 hour Then, a wafer having a polyimide resin film formed was produced. Using this wafer, a silicon nitride (SiNx) film, which is an inorganic film, is formed on a polyimide resin film by CVD at a temperature of 350 ° C. to a thickness of 100 nm to form an inorganic film / polyimide resin. I got

The laminate wafer obtained above was immersed in a dilute hydrochloric acid aqueous solution, and the inorganic film and the two layers of the polyimide film were integrally peeled off from the wafer to obtain a sample of a polyimide film having an inorganic film formed on the surface. The warp of the polyimide resin film was evaluated using this sample.
◎: There is no warp (warp "excellent")
○: A little warpage (warp "good")
X: film curled up due to warpage (warped "defect")

<Evaluation of yellowness (YI value)>
A wafer (in which an inorganic film was not formed) was produced in the same manner as in the above <Evaluation of Warpage of Polyimide Resin Film Having Inorganic Film Formed>. The wafer was immersed in dilute aqueous hydrochloric acid solution, and the polyimide resin film was peeled off to obtain a resin film.
About the obtained polyimide resin film, YI value (film thickness 10micrometer conversion) was measured using Nippon Denshoku Kogyo Co., Ltd. product (Spectrophotometer: SE600) using D65 light source.

<Evaluation of elongation and breaking strength>
A wafer (in which an inorganic film was not formed) was produced in the same manner as in the above <Evaluation of Warpage of Polyimide Resin Film Having Inorganic Film Formed>. After a 3 mm wide cut was made in the polyimide resin film of the wafer using a dicing saw (DAD 3350, manufactured by Disco Corporation), the resin film pieces were peeled off by dipping in a dilute aqueous hydrochloric acid solution overnight and dried. This was cut into a length of 50 mm and used as a sample.
The elongation and breaking strength of the above samples were measured at a test speed of 40 mm / min and an initial load of 0.5 fs using TENSILON (UTM-II-20 manufactured by Orientec Co., Ltd.).
<Absorbance measurement at 308 nm of polyimide resin film>
The varnish was spin-coated on a quartz glass substrate, and heated at 430 ° C. for 1 hour in a nitrogen atmosphere to obtain a polyimide resin film having a thickness of 0.1 μm. The absorbance at 308 nm of these polyimide films was measured using UV-1600 (manufactured by Shimadzu Corporation).

Example 1
In a nitrogen-substituted 500 ml separable flask, 96 g of N-methyl-2-pyrrolidone (NMP) is placed, 17.71 g (77.6 mmol) of 4-aminophenyl-4-aminobenzoate (APAB) and 4,4'- 4.82 g (19.4 mmol) of diaminodiphenyl sulfone (DAS) was charged and stirred to dissolve APAB and DAS. Thereafter, 29.42 g (100 mmol) of biphenyl-3,3 ′, 4,4′-tetracarboxylic acid dianhydride (BPDA) was added, and a polymerization reaction was carried out under nitrogen flow at 80 ° C. for 3 hours with stirring. Then, it cooled to room temperature and the said NMP was added and it adjusted so that solution viscosity might be 51,000 mPa * s, and obtained the NMP solution (it is also called the varnish hereafter) P-1 of a polyamic acid. The weight average molecular weight (Mw) of the obtained polyamic acid was 65,000.

[Examples 2 to 21 and Comparative Examples 1 to 5]
The same procedure as in Example 1 was repeated except that the feed amounts (molar ratio) of the raw materials, the type of solvent used, the polymerization temperature and the polymerization time were changed as described in Table 1, respectively. And varnishes P-2 to P-26.
The weight average molecular weight (Mw) of the polyamic acid contained in each varnish is shown together in Table 1.

The abbreviation of each component in Table 1 has the following meaning, respectively.
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic acid dianhydride PMDA: pyromellitic acid dianhydride TAHQ: p-phenylene bis (trimellitic anhydride)
APAB: 4-aminophenyl-4-aminobenzoate ATAB: 2-methyl-4-aminophenyl-4-aminobenzoate BABB: [4- (4-aminobenzoyl) oxyphenyl] 4-aminobenzoate BAFL: 9, 9- Bis (aminophenyl) fluorene BFAF: 9,9-bis (4-amino-3-fluorophenyl) fluorene TFMB: 2, 2′-bis (trifluoromethyl) benzidine DAS: 4,4′-diaminodiphenyl sulfone NMP: N-methyl-2-pyrrolidone DMF: N, N-dimethylformamide DMAc: N, N-dimethylacetamide

  The varnishes P-1 to P-26 obtained in the above-mentioned Examples and Comparative Examples were used as they were as resin compositions, and were evaluated according to the above-mentioned method. The evaluation results are shown in Table 2.

As is clear from Tables 1 and 2, the polyimide films obtained in Comparative Examples 1 and 2 containing only the structural unit represented by the general formula (1) are fragile in the film, and physical properties such as elongation can be evaluated. It was not. Also, the residual stress was high. In addition, the polyimide film obtained in Comparative Example 3 containing only the structural unit represented by the general formula (2) had high residual stress, and after forming the inorganic film, warpage occurred and the elongation was also low.
On the other hand, a polyimide film obtained from Examples 1 to 21 containing the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) in a molar ratio of 99/1 to 1/99. The result was that the yellowness was as low as 20 or less, the residual stress was as low as 25 MPa or less, and the elongation was as high as 20% or more. In addition, no warping occurred after forming the inorganic film, or only slight if any.
From the results of Table 2 above, it was confirmed that the polyimide resin film obtained from the resin composition according to the present invention is a resin film having a low degree of yellowness, low residual stress, and excellent mechanical properties.
Specifically, in the present invention, a resin film having a residual stress of 25 MPa or less, a yellowness degree YI of 30 or less, and an elongation of 15% or more is obtained.

Example 22
In a nitrogen-substituted 500 ml separable flask, add N-methyl-2-pyrrolidone (NMP) (water content 250 mass ppm) immediately after opening the 18 L can to a quantity corresponding to a solid content of 17 wt%, 4-aminophenyl 5.71 g (25.0 mmol) of -4-aminobenzoate (APAB, purity 99.5%, manufactured by Nihon Junryo Pharmaceutical Co., Ltd.) was added and stirred to dissolve APAB. After that, 7.36 g (25.0 mmol) of biphenyl-3,3 ', 4,4'-tetracarboxylic acid dianhydride (BPDA, purity 99.5%, manufactured by Manac Corporation) is added, and 80 under nitrogen flow The polymerization reaction was carried out with stirring for 3 hours at ° C. Thereafter, the solution was cooled to room temperature, and the NMP was added thereto to adjust the solution viscosity to 51,000 mPa · s, thereby obtaining an NMP solution of polyamic acid (hereinafter, also referred to as a varnish) P-27. The weight average molecular weight (Mw) of the obtained polyamic acid was 128,000, and the content of molecules having a molecular weight of less than 1,000 was 0.01% by mass.

[Examples 23 to 33 and Comparative Examples 6 to 11]
Example 22 is the same as Synthesis Example 1 except that the kind of raw material, the preparation amount of the raw material, the kind of solvent used, the polymerization temperature, and the polymerization time are changed as described in Table 3, respectively. Varnishes P-28 to P-44 were obtained.
The weight average molecular weight (Mw) of the polyamic acid contained in each varnish is shown together in Table 3.

The abbreviation of each component in Table 3 has the following meaning, respectively.
BPDA: biphenyl tetracarboxylic acid dianhydride, purity 99.5%, Mitsubishi Chemical Co., Ltd. TAHQ: p-phenylene bis (trimellitate acid anhydride), purity 99.5%, Manac Corporation PMDA: pyromellitic acid 2 Anhydride APAB: 4-aminophenyl-4-aminobenzoate, 99.5% purity
4, 3-APAB: 4-aminophenyl-3-aminobenzoate, 99.5% purity
ATAB: 2-methyl-4-aminophenyl-4-aminobenzoate BABB: [4- (4-aminobenzoyl) oxyphenyl] 4-aminobenzoate NMP 1:18 L cans immediately after opening, water content 250 ppm
NMP 2: 500 ml bottled product left for 1 month after opening, water content 3,070 ppm
DMF: 500 ml bottle after opening, water content 3510 ppm
DMAc: 500 ml bottle after opening, water content 3430 ppm

[Examples 22 to 33 and Comparative Examples 6 to 11]
Evaluation was performed according to the above-mentioned method, using varnish P-27-P-44 obtained by the said Example and comparative example as a resin composition as it was. The evaluation results are shown in Table 4.

As apparent from Tables 3 and 4, Comparative Example 6 (P-39), Comparative Example 7 (P-40) and Comparative Example 8 (P In -41), the comparative example 10 (P-43) and the comparative example 11 (P-44), the residual stress was large and the warpage was also large. Moreover, yellowness was large and elongation and breaking strength were also small. In particular, in Comparative Examples 10 and 11 in which the water content was high, the film was very brittle.
On the other hand, in Comparative Example 9 (P-42) in which the weight average molecular weight of the polyimide precursor is 30,000 or more, the residual stress and warpage were small, the yellowness was also low, and the elongation and breaking strength were also large. It got worse.
On the other hand, in Examples 22 to 33 using polyimide precursors P-27 to P-38 having a weight average molecular weight of 30,000 or more and 300,000 or less, residual stress is low and warpage is also small, and yellow Excellent results were obtained with any of the properties, which are low in degree and high in elongation and breaking strength.

From the results of Table 4 above, it was confirmed that the polyimide resin film obtained from the resin composition according to the present invention is a resin film having a low degree of yellowness, low residual stress, and excellent mechanical properties.
Specifically, in the present invention, the residual stress is 25 MPa or less, the yellowness YI is 20 or less, the glass transition temperature is 400 ° C. or more, the elongation is 15% or more, and the breaking strength is 250 MPa. The resin film which is the above is obtained.

In Examples 34 to 45 shown below, experiments were conducted on the effect of adding at least one selected from the group consisting of a surfactant and an alkoxysilane compound to the resin composition.
[Example 34]
First, using the varnish P-27 obtained in Example 22 as a resin composition as it was, evaluation of coating streaks was performed according to the following procedure.
<Evaluation of coating streaks (coating property)>
The above resin composition was coated on an alkali-free glass substrate (size 37 × 47 mm, thickness 0.7 mm) using a bar coater so as to have a film thickness of 15 μm after curing. After coating, the film was allowed to stand at room temperature for 10 minutes, and it was visually confirmed whether a coating streak occurred in the obtained coating film. Coating was performed three times using the same resin composition, the number of coating streaks was checked for each coating film, and the evaluation was made according to the following criteria using the average value.
◎: 0 continuous coating streaks with a width of 1 mm or more and a length of 1 mm or more (evaluation of coating streaks “excellent”)
:: 1 or 2 coating streaks described above (evaluation of coating streaks “good”)
:: 3 to 5 of the above coating streaks (Evaluation of coating streaks "OK")
The evaluation results are shown in Table 5.

[Examples 35 to 45]
A surfactant or an alkoxysilane compound of the type and amount shown in Table 5 is added to the varnish P-27 obtained in Example 22 as an additional additive, and then filtered with a 0.1 μm filter. , A resin composition was prepared.
The coating streaks were evaluated in the same manner as in Example 34 using the above resin composition. The results are shown in Table 5.

The abbreviation of each component in Table 5 has the following meanings. The amounts used of these components in Table 5 are the amounts (amounts used) with respect to 100 parts by mass of the polyimide precursor contained in the varnish. In Examples 39 and 45, surfactant 1 and alkoxysilane compound 1 were used in combination.
Surfactant 1: DBE-821, product name, silicone surfactant, manufactured by Gelest Surfactant 2: Megafac F171, product name, fluorosurfactant, manufactured by DIC alkoxysilane compound 1: General formula (AS below) Compound Represented by -1) Alkoxysilane Compound 2: Compound Represented by General Formula (AS-2)

  As apparent from Table 5, in Examples 35 to 39 and Examples 41 to 45, which contained a surfactant or an alkoxysilane compound, generation of coating streaks was observed as compared with Examples 34 and 40, which did not contain a surfactant or an alkoxysilane compound. It was found that a polyimide resin film excellent in surface smoothness can be obtained.

[Example 46]
Varnish P-27 was coated on an alkali free glass substrate (size 37 × 47 mm, thickness 0.7 mm) using a bar coater to a cured film thickness of 10 μm, and then prebaked at 140 ° C. for 60 minutes. Subsequently, using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B), the oxygen concentration in the chamber is adjusted to 10 mass ppm or less, and heat curing treatment is performed at 430 ° C. for 1 hour Then, a glass substrate on which a polyimide resin film was formed was produced. An amorphous silicon layer was formed on this polyimide film, dehydrogenation annealing was performed at 430 ° C. for one hour, and then an excimer laser was irradiated to form an LTPS layer. The glass substrate was peeled off by an excimer laser (wavelength 308 nm, repetition frequency 300 Hz) to obtain a laminate including a polyimide film and an LTPS layer.
This laminate did not warp and had a yellowness of 20 or less.

[Example 47]
A laminate was obtained in the same manner as in Example 46 except that the varnish P-1 was used. This laminate did not warp and had a yellowness of 20 or less.

Comparative Example 12
A laminate was obtained in the same manner as in Example 46 except that Varnish P-24 was used. This laminate had a large amount of warpage, and a part of the polyimide film was cracked.

[Composition example]
Under a nitrogen atmosphere, 2.24 g (9.8 mmol) of APAB, 16.14 g of NMP and 50 g of toluene were charged into a separable flask equipped with a Dean-Stark apparatus and a reflux condenser, and APAB was dissolved under stirring. To this, 2.24 g (10.0 mmol) of H-PMDA was added, and after refluxing at 180 ° C. for 2 hours, toluene which is an azeotropic solvent was removed over 3 hours. The contents of the flask were cooled to 40 ° C., and it was confirmed by IR that the absorption (C = O) in the vicinity of 1,650 cm ⁻¹ derived from the amide bond had disappeared. Then add 8.95 g (39.2 mmol) of APAB, 121.6 g of NMP, 6.54 g (30.0 mmol) of PMDA and 4.44 g (10.0 mmol) of 6FDA and stir at 80 ° C. for 4 hours Thus, a varnish of polyimide-polyamic acid polymer was obtained (P-45). The weight average molecular weight (Mw) of the obtained polyimide-polyamic acid polymer was 82,000.

[Examples 48 to 53, Comparative Example 13]
An organic EL substrate as shown in FIG. 1 was produced.
Polyimide precursor varnish (P-1, P-11, P-20, P-22, P-27, P-33, P-45) using a bar coater on a mother glass substrate (0.7 mm thick) The composition was applied to a film thickness of 10 μm after curing, and then prebaked at 140 ° C. for 60 minutes. Subsequently, using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B), the oxygen concentration in the chamber is adjusted to 10 mass ppm or less, and heat curing treatment is performed at 430 ° C. for 1 hour Then, a glass substrate on which a polyimide resin film was formed was produced.
Subsequently, a SiN layer was formed to a thickness of 100 nm by a CVD (Chemical Vapor Deposition) method.

Subsequently, titanium was formed into a film by sputtering, and then patterning was performed by photolithography to form a scanning signal line.
Next, a SiN layer was formed to a thickness of 100 nm by the CVD method on the entire glass substrate on which the scanning signal lines were formed. (This is the lower substrate 2a.)
Subsequently, an amorphous silicon layer 256 was formed on the lower substrate 2 a, dehydrogenation annealing was performed at 430 ° C. for 1 hour, and then an excimer laser was irradiated to form an LTPS layer.
Thereafter, a photosensitive acrylic resin is coated on the entire surface of the lower substrate 2a by spin coating, and exposure and development are performed by photolithography to form a plurality of contact holes 257. A portion of each LTPS 256 was exposed by the contact hole 257.
Next, an ITO film is formed on the entire surface of lower substrate 2a on which interlayer insulating film 258 is formed by sputtering, exposed and developed by photolithography, and patterned by etching to form a pair with each LTPS. The lower electrode 259 was formed as follows.
In each contact hole 257, the lower electrode 252 penetrating the interlayer insulating film 258 and the LTPS 256 are electrically connected.
Next, after the partition wall 251 was formed, in each space partitioned by the partition wall 251, the hole transport layer 253 and the light emitting layer 254 were formed. Further, the upper electrode 255 was formed so as to cover the light emitting layer 254 and the partition wall 251. The organic EL substrate 25 was produced by the above steps.
Next, a UV curable resin is coated on the periphery of the sealing substrate 2b on which the glass substrate, the polyimide film of the present embodiment and the SiN layer are formed in this order, and the sealing substrate 2b and the organic EL substrate are By bonding, the organic EL element was enclosed. Thus, hollow portions 261 were formed between the organic EL elements and the sealing substrate 2b.

Excimer laser (wavelength 308 nm, repetition frequency 300 Hz) was irradiated from the lower substrate 2 a side and the sealing substrate 2 b side of the laminate formed in this way, and peeling was performed with the minimum energy necessary to peel the entire surface. .
With respect to the laminate of the above, the evaluation of the presence or absence of the substrate warpage after peeling, the lighting test, and the white turbidity evaluation of the laminate was performed. In addition, the heat cycle test was also conducted. The results are shown in Table 6.
<Board warpage>
:: not warped ○: slightly warped △: curled due to warp <lighting test>
○: lighted ×: not lighted <layer whitening evaluation>
After the formation of the laminate, the transparent device was rated as 、, the one with a slight cloudiness as △, and the one with a cloudiness as ×.
<Heat cycle test>
The appearance observation after conducting 1000 cycles of test at -5 ° C. and 60 ° C. for 30 minutes (moving time of the tank 1 minute) was performed using a heat cycle tester manufactured by ESPEC.
Those with no peeling or swelling were marked with ○, those with peeling or swelling observed in part after the test were marked Δ, and those with peeling or swelling observed after the test were marked ×.

[Examples 54 to 58, Comparative Example 14]
Except that, when using the polyimide precursor varnish (P-1, P-11, P-20, P-22, P-27, P-33, P-45), LTPS was changed to IGZO during the production of the above laminate. Carried out laminate production and conducted the above test. The results are shown in Table 7.

[Examples 59 to 63, Comparative Example 15]
Polyimide precursor varnish (P-1, P-11, etc.) giving an absorbance of 0.6 to 2.0 and an elongation of 15% or more at an YI of 20 or less and a film thickness of 0.1 micron. As for P-20, P-27, P-33, and P-45, ash when irradiated with the minimum energy required for laser peeling at the time of laser peeling described above, and the energy obtained by adding 10 mJ / cm ² to the minimum energy ( The ash content was evaluated. A sample in which no ash was generated was evaluated as も の, a sample in which a small amount of ash was observed in the pot was △, and a sample in which ash was observed in the entire surface was ×. The results are shown in Table 8.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  The resin film formed from the polyimide precursor of the present invention can be applied to, for example, a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, etc. It can be suitably used as

Claims (6)

The following general formula (13):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. A polyimide film layer containing a polyimide represented by
A low temperature polysilicon TFT layer formed on the polyimide film layer.   The flexible display according to claim 1, wherein a yellowness YI at a film thickness of 10 μm of the polyimide film layer is 30 or less.   The flexible display according to claim 1, wherein a tensile elongation of the polyimide film layer is 15% or more. The following general formula (13):

Wherein X ₁ represents a tetravalent group having 4 to 32 carbon atoms. R ₁ , R ₂ and R ₃ each independently represent a monovalent organic group having 1 to 20 carbon atoms. n represents 0 or 1; And a, b and c are integers of 0-4. Forming a polyimide film layer containing a polyimide represented by
Forming a low temperature polysilicon TFT layer on the polyimide film layer;
A method of manufacturing a flexible display, including: Forming the polyimide film layer on a support;
Peeling the polyimide film layer from the support;
The method of manufacturing a flexible display according to claim 4, comprising: Peeling the polyimide film layer from the support by laser peeling;
A method of manufacturing a flexible display according to claim 5, comprising:

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