JP6775768B2 - Composition for forming a release layer - Google Patents

Description

The present invention relates to a composition for forming a release layer provided directly above a glass substrate.

In recent years, electronic devices are required to have a function of bending, and to be thinner and lighter. For this reason, it is required to use a lightweight flexible plastic substrate instead of the conventional heavy, fragile and inflexible glass substrate. Further, in the new generation display, development of an active full-color TFT display panel using a lightweight flexible plastic substrate is required.
Therefore, various methods for manufacturing electronic devices using a resin film as a substrate have begun to be studied, and for new-generation displays, manufacturing studies are being carried out by a process in which existing TFT equipment can be diverted.

In Patent Documents 1, 2 and 3, an amorphous silicon thin film layer is formed on a glass substrate, a plastic substrate is formed on the thin film layer, and then a laser is irradiated from the glass surface side to accompany the crystallization of amorphous silicon. A method of peeling a plastic substrate from a glass substrate by the generated hydrogen gas is disclosed.
Further, Patent Document 4 is a method of completing a liquid crystal display device by attaching a peelable layer (described as a “transfer layer” in Patent Document 4) to a plastic film using the techniques disclosed in Patent Documents 1 to 3. To disclose.

However, in the methods disclosed in Patent Documents 1 to 4, particularly in the method disclosed in Patent Document 4, it is essential to use a substrate having high translucency, and hydrogen contained in amorphous silicon is further passed through the substrate. In order to give sufficient energy to emit it, it is necessary to irradiate a relatively large laser beam, and there is a problem that the layer to be peeled is damaged. Further, since the laser treatment requires a long time and it is difficult to peel off the layer to be peeled off having a large area, there is also a problem that it is difficult to increase the productivity of device fabrication.

Japanese Unexamined Patent Publication No. 10-125929. Japanese Unexamined Patent Publication No. 10-125931. WO2005 / 050754 pamphlet. Japanese Unexamined Patent Publication No. 10-125930.

Therefore, an object of the present invention is to solve the above problems.
Specifically, an object of the present invention is to provide a composition for forming a release layer for peeling without damaging a substrate applied to a flexible electronic device.

Further, an object of the present invention is, in addition to or other than the above-mentioned object, to maintain adhesion to a glass substrate provided with a release layer and prevent peeling at an interface with the glass substrate, while being more than a release layer. It is an object of the present invention to provide a composition for forming the peeling layer, which can easily peel the layer or group formed on the upper part from the peeling layer.

The present inventor has recently found the following inventions. That is, the present inventor forms a release layer using a composition containing a polyamic acid containing 50 mol% or more of monomer units having a specific structure and a weight average molecular weight of a certain value or more, and an organic solvent. It was unexpectedly found that the layer has suitable properties that can be peeled off without damaging the substrate applied to flexible electronic devices and the like. This layer maintains adhesion to the glass substrate on which the release layer is provided and is unlikely to peel off at the interface with the glass substrate, while the layer or layer formed above the release layer on the opposite side of the glass substrate. For the group, it was possible to easily peel off from the peeling layer. The present invention is based on such findings.

［式中、Ｘ^１は、４価の有機基を表し、Ｙ^１は、下記の式（Ｐ）で表される２価の基を表す：

（式中、Ｒは、Ｆ、Ｃｌ、炭素数１〜３のアルキル基、又はフェニル基を表し、ｍは、０〜４の整数を表し、かつ、ｒは１〜４の整数を表す）］。 <1> A composition for forming a release layer, which comprises a polyamic acid having a weight average molecular weight of 10,000 or more and containing 50 mol% or more of the monomer units represented by the following formula (1), and an organic solvent.

[In the formula, X ¹ represents a tetravalent organic group, and Y ¹ represents a divalent group represented by the following formula (P):

(In the formula, R represents F, Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, m represents an integer of 0 to 4, and r represents an integer of 1 to 4)] ..

（式中、
Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６は、同一であっても異なっていてもよく、Ｆ、Ｃｌ、炭素数１〜３のアルキル基、又はフェニル基を表し、
ｍ１、ｍ２、ｍ３、ｍ４、ｍ５及びｍ６は、同一であっても異なっていてもよく、０〜４の整数を表す）。 <2> In the above <1>, the Y ¹ is preferably a divalent group represented by any of the following formulas (P1) to (P3).

(During the ceremony,
R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different, representing F, Cl, an alkyl group having 1-3 carbon atoms, or a phenyl group.
m1, m2, m3, m4, m5 and m6 may be the same or different and represent an integer of 0-4).

<3> the <2> wherein ^{Y 1} is better to include a divalent group represented by the least expression (P1).

［式中、
Ｘ^１は、前記＜１＞で定義されたとおりであり、Ｙ^２は、下記の式（Ｐ４）で表される基を表す：

（式中、
Ｒ^７、及びＲ^８は、同一であっても異なっていてもよく、Ｆ、Ｃｌ、炭素数１〜３のアルキル基、又はフェニル基を表し、
Ｒ’は、水素原子、炭素数１〜３のアルキル基、又はフェニル基を表し、 ｌは０〜４の整数を表し、かつ
ｍは、前記＜１＞で定義されたとおりである）］。 <4> In any of the above <1> to <3>, the polyamic acid may further contain a monomer unit represented by the following formula (2).

[During the ceremony,
X ¹ is as defined in <1> above, and Y ² represents a group represented by the following formula (P4):

(During the ceremony,
R ⁷ and R ⁸ may be the same or different, and represent F, Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group.
R'represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, l represents an integer of 0 to 4, and m is as defined in <1> above)].

<5> In any of the above <1> to <4>, X ¹ is preferably a tetravalent aromatic group.

<6> In <5>, the tetravalent aromatic group preferably has at least one selected from a benzene skeleton, a naphthalene skeleton, and a biphenyl skeleton.

（式中、Ｒ^ａ及びＲ^ｂは同一であっても異なっていてもよく、炭素数１〜４のアルキル基を表し、ｈは自然数を表す）。 <7> In any of the above <1> to <6>, the organic solvent is preferably a solvent represented by the following formula (A) or (B).

(In the formula, ^Ra and R ^b may be the same or different, and represent an alkyl group having 1 to 4 carbon atoms, and h represents a natural number).

<8> In any of the above <1> to <7>, the content of the monomer unit represented by the formula (1) in the polyamic acid is preferably 60 mol% or more.

<9> In any of the above <1> to <8>, the composition for forming a release layer according to the present invention is preferably for forming a release layer provided directly above the glass substrate.

<10> A release layer formed between a flexible substrate applied to a flexible electronic device and a base substrate, using the release layer forming composition according to any one of <1> to <9>. The peeling layer to be produced.

<11> A substrate structure applied to flexible electronic devices.
With the base board
A release layer that covers the base substrate in one or more regions and is formed by the release layer forming composition according to any one of <1> to <9>.
A flexible substrate that covers the base substrate and the release layer.
A substrate structure characterized in that the adhesion between the flexible substrate and the release layer is larger than the adhesion between the release layer and the base substrate.

<12> In the above <11>, the base substrate preferably contains glass.

<13> A method for producing a release layer, which comprises using the composition for forming a release layer according to any one of <1> to <9>. In one preferred embodiment, the method for producing the release layer includes a step of applying the resin composition for forming the release layer to a substrate and heating the substrate.

<14> A method for manufacturing a substrate structure applied to a flexible electronic device.
The process of preparing the base board,
A step of preparing a release layer covering the base substrate in one or more regions using the composition for forming a release layer according to any one of <1> to <9>.
A step of forming a flexible substrate on the base substrate and the release layer is included.
A production method, wherein the adhesion between the flexible substrate and the release layer is larger than the adhesion between the release layer and the base substrate.

According to the present invention, the above problems can be solved.
Specifically, the present invention can provide a composition for forming a release layer for peeling a substrate applied to a flexible electronic device without damaging it.
Further, according to the present invention, in addition to or other than the above effects, the adhesion to the glass substrate on which the release layer is provided is maintained and peeling does not occur at the interface with the glass substrate, while above the release layer. It is an object of the present invention to provide a composition for forming the peeling layer, which can easily peel the layer or group to be formed from the peeling layer.

Hereinafter, the present invention will be described in detail.

Composition for forming a release layer As described above, the composition for forming a release layer of the present invention is a polyamic acid containing 50 mol% or more of the monomer units represented by the formula (1), and the weight average molecular weight thereof is 10. It contains 000 or more polyamic acids and an organic solvent.

Further, as described above, in the formula (1), X ¹ represents a tetravalent organic group, and Y ¹ represents a divalent group represented by the following formula (P).

Further, in the formula (P), R represents F, Cl, or an alkyl group having 1 to 3 carbon atoms or a phenyl group, and preferably represents F, Cl. Similarly, in the above formula (P), m represents an integer of 0 to 4, preferably 0 to 2, more preferably 0 to 1, and particularly preferably 0. Further, in the above equation (P), r represents an integer of 1 to 3.
The alkyl group having 1 to 3 carbon atoms includes methyl, ethyl, n-propyl, and i-propyl, and the alkyl group having 1 to 3 carbon atoms is preferably methyl, and more preferably. It is methyl.

The weight average molecular weight of the polyamic acid having the monomer unit represented by the formula (1) used in the present invention needs to be 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and more. More preferably, it is 30,000 or more. On the other hand, the upper limit of the weight average molecular weight of the polyamic acid used in the present invention is usually 2,000,000 or less, but it is possible to prevent the viscosity of the resin composition from becoming excessively high and to have a highly flexible resin thin film. It is preferably 1,000,000 or less, more preferably 200,000 or less, in consideration of obtaining good reproducibility.

The polyamic acid used in the present invention contains the monomer unit represented by the formula (1) in an amount of 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more, and further. It is preferably contained in an amount of 90 mol% or more. By using a polyamic acid having such a monomer unit content, a resin thin film having properties suitable for a release film can be obtained with good reproducibility.

According to a preferred embodiment of the present invention, the polyamic acid contained in the composition for forming a release layer of the present invention is a polymer consisting only of a monomer unit represented by the formula (1), that is, a monomer represented by the formula (1). It is a polymer contained in 100 mol% of units. At this time, the monomer unit in such a polyamic acid may be only one specific type or two or more types as long as it is represented by the formula (1). In the latter case, the number of monomer units of the formula (1) contained in the polyamic acid is preferably 2 to 4, more preferably 2 to 3.

In the present invention, the group represented by the formula (P) preferably contains a divalent group represented by any of the formulas (P1) to (P3), and more preferably the formula (P1) or (P3). ) Is included, and even more preferably, a divalent group represented by the formula (P3) is contained.

Wherein the formula (P1), in the formula (P2) and the formula ^{(P3), R 1, R} 2, R 3, R 4, R 5 and ^{R 6,} which may be independently identical or different, F, It represents Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, and preferably F or Cl.
Similarly, in these equations, m1, m2, m3, m4, m5 and m6 may be the same or different, representing an integer of 0-4, preferably 0-2, more preferably 0. It represents ~ 1, and particularly preferably 0.

The polyamic acid used in the present invention may contain other monomer units in addition to the monomer unit represented by the formula (1). The content of such other monomer units should be less than 50 mol%, preferably less than 40 mol%, more preferably less than 30 mol%, less than 20 mol%. Is even more preferable, and less than 10 mol% is further preferable.

Examples of such other monomer units include the monomer unit of the formula (2).

In the formula (2), X ¹ represents a tetravalent organic group, and Y ² represents a group represented by the above formula (P4).

In formula (P4), R ⁷ and R ⁸ may be the same or different, and represent F, Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group. R ⁷ preferably represents F or Cl. R ⁸ preferably represents F, or Cl.
R'represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, preferably a hydrogen atom, or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom.
Further, l and m may be the same or different, and represent an integer of 0 to 4, preferably 0 to 2, more preferably 0 to 1, and particularly preferably 0.

As such other monomer units, in addition to the monomer unit of the above formula (2), o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2-methyl-1,4-phenylenediamine, 5 -Methyl-1,3-phenylenediamine, 4-methyl-1,3-phenylenediamine, 2- (trifluoromethyl) -1,4-phenylenediamine, 2- (trifluoromethyl) -1,3-phenylenediamine And 4- (trifluoromethyl) -1,3-phenylenediamine, benzidine, 2,2'-dimethylbenzidine, 3,3'-dimethylbenzidine, 2,3'-dimethylbenzidine, 2,2'-bis (tri) Fluoromethyl) benzidine, 3,3'-bis (trifluoromethyl) benzidine, 2,3'-bis (trifluoromethyl) benzidine, 4,4'-diphenyl ether, 4,4'-bis (4-aminophenoxy) Diamines such as biphenyl, 4,4'-diaminobenzidine, 5-amino-2- (3-aminophenyl) -1H-benzoimidazole, 9,9-bis (4-aminophenyl) fluorene, and pyromellitic anhydride (PMDA), 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, etc. Examples include structures derived from objects.

In the formulas (1) and (2), as described above, X ¹ is a tetravalent organic group, preferably a tetravalent aromatic group.

The tetravalent aromatic group that X ¹ can take can be prepared by using the following aromatic tetracarboxylic dianhydride when preparing the polyamic acid used in the present invention.
That is, pyromellitic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, 2,3,3 ', 4'-biphenyltetracarboxylic acid dianhydride, 3,3', 4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 1, 2,5,6-naphthalenetetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 3,3', 4,4'-dimethyldiphenylsilanetetracarboxylic acid dianhydride, 3,3', 4 , 4'-Tetraphenylsilane tetracarboxylic acid dianhydride, 1,2,3,4-frantetracarboxylic acid dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride , 4,4'-Hexafluoroisopropyridendiphthalic anhydride, paraphenylenediphthalic hydride, 2,2-bis-((3,4-dicarboxyphenyl) -hexafluoropropane dianhydride, 9) , 9-bis (3,4-dicarboxyphenyl) fluorene dianhydride, 9,9'-bis [4- (3,4-dicarboxyphenoxy) phenyl] fluorene hydride, 3,3', 4, 4'-biphenyl ether tetracarboxylic acid dianhydride, 2,3,5,6-pyridinetetracarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 4,4'-sulfonyl Diphthalic acid dianhydride, paraterphenyl-3,4,3', 4'-tetracarboxylic acid dianhydride, metaterphenyl-3,3', 4,4'-tetracarboxylic acid dianhydride, 3 , 3', 4,4'-diphenyl ether tetracarboxylic acid dianhydride, 1,3-bis (3,4-dicarboxyphenyl) -1,1,3,3-tetramethyldisiloxane dianhydride, 1- (2,3-dicarboxyphenyl) -3- (3,4-dicarboxyphenyl) -1,1,3,3-tetramethyldisiloxane dianhydride, 3,3', 4,4'-hydroquinonedi Examples thereof include benzoate tetracarboxylic dianhydride, 2,2'-bis (4-hydroxyphenyl) propandibenzoate-3,3', 4,4'-tetracarboxylic acid and the like.

（式中、Ｒ_３は、芳香環を少なくとも１つ有する２価の有機基であり、好ましくは、フェニル、ビフェニル、ナフタレン骨格を有する基である）。 Preferably, the aromatic tetracarboxylic dianhydride desired here is selected from the following compound group.

(In the formula, R ₃ is a divalent organic group having at least one aromatic ring, preferably a group having a phenyl, biphenyl, naphthalene skeleton).

Therefore, according to a preferred embodiment of the present invention, the tetravalent aromatic group that X ¹ can take has any one of a benzene skeleton, a naphthalene skeleton, a biphenyl skeleton, and a terphenyl skeleton, and more preferably benzene. It has any of a skeleton, a naphthalene skeleton, and a biphenyl skeleton, and more preferably, it has any of a benzene skeleton and a biphenyl skeleton.

According to a preferred embodiment of the present invention, the polyamic acid used in the present invention includes 3,3', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) (formula (4)) as an acid dianhydride. , P-phenylenediamine (pPDA) as a diamine (formula (5)) and 4,4 "-diamino-p-terphenyl (DATP) (formula (6)), or pyromellitic acid as an acid dianhydride. It can be obtained by reacting a dianhydride (PMDA) (formula (7)) with pPDA (formula (5)) as a diamine.

In the above reaction, it consists of 3,3', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), p-phenylenediamine (pPDA) and 4,4 "-diamino-p-terphenyl (DATP). The charging ratio (molar ratio) of diamine or pyromellitic dianhydride (PMDA) and pPDA can be appropriately set in consideration of the desired molecular weight of polyamic acid, the ratio of monomer units, etc., but the amine component Generally, the acid anhydride component can be about 0.7 to 1.3, preferably about 0.8 to 1.2 with respect to 1.

On the other hand, the charging ratio of the diamines pPDA and DATP can be such that the amount of substance (m ¹ ) of pPDA is usually about 1.7 to 20 when the amount of substance (m ² ) of DATP is ^1. However, it is preferably 2.1 to 20, more preferably 2.2 to 20, even more preferably 2.3 to 19, and even more preferably 2.3 to 18. That is, m ¹ and m ² are usually m ¹ / m ² = 1.7 to 20, preferably 2.1 to 20, more preferably 2.2 to 20, and even more preferably. It is 2.3 to 19, and more preferably 2.3 to 18.

The above reaction is carried out in an organic solvent. That is, the composition for forming a release layer according to the present invention contains such an organic solvent. As the organic solvent that can be used here, various solvents can be used as long as they do not adversely affect the reaction.
Specific examples include m-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide. , 3-methoxy-N, N-dimethylpropylamide, 3-ethoxy-N, N-dimethylpropylamide, 3-propoxy-N, N-dimethylpropylamide, 3-isopropoxy-N, N-dimethylpropylamide, Protonic solvents such as 3-butoxy-N, N-dimethylpropylamide, 3-sec-butoxy-N, N-dimethylpropylamide, 3-tert-butoxy-N, N-dimethylpropylamide, γ-butyrolactone, etc. Can be mentioned. These may be used alone or in combination of two or more.

According to a preferred embodiment of the present invention, the organic solvent is a solvent represented by the formula (A) or (B).

In the formulas (A) and (B), ^Ra and R ^b may be the same or different, and represent an alkyl group having 1 to 4 carbon atoms, preferably 1 to 3 carbon atoms. Further, here, h represents a natural number, and is preferably 1 to 3.

The reaction temperature may be appropriately set in the range from the melting point to the boiling point of the solvent to be used, and is usually about 0 to 100 ° C., but imidization of the obtained polyamic acid is prevented and a high content of the polyamic acid unit is maintained. For this purpose, the temperature is preferably about 0 to 70 ° C, more preferably about 0 to 60 ° C, and even more preferably about 0 to 50 ° C.
The reaction time cannot be unconditionally defined because it depends on the reaction temperature and the reactivity of the raw material, but it is usually about 1 to 100 hours.

By the method described above, a reaction solution containing the desired polyamic acid can be obtained.

In the present invention, usually, after filtering the above reaction solution, the filtrate is used as it is, or diluted or concentrated and used as a composition for forming a release layer. By doing so, it is possible not only to reduce the mixing of impurities that may cause deterioration of the heat resistance, flexibility or linear expansion coefficient characteristics of the obtained resin thin film, but also to efficiently obtain the composition.
The solvent used for dilution or concentration is not particularly limited, and examples thereof include the same ones as the specific examples of the reaction solvent for the above reaction, and they may be used alone or in combination of two or more. ..

Among these, considering that a highly flat resin thin film can be obtained with good reproducibility, the solvents used are N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3. -Dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, γ-butyrolactone are preferred.

The concentration of the polyamic acid with respect to the total mass of the composition for forming the release layer is appropriately set in consideration of the thickness of the thin film (release layer) to be produced, the viscosity of the composition, etc., but is usually about 0.5 to 30% by mass. It is preferably about 5 to 25% by mass.

The viscosity of the composition for forming a release layer is also appropriately set in consideration of the thickness of the thin film to be produced, but the purpose is to obtain a resin thin film having a thickness of about 0.05 to 5 μm with good reproducibility. In this case, it is usually about 10 to 10,000 mPa · s at 25 ° C., preferably about 20 to 1000 mPa · s, and more preferably about 20 to 200 mPa · s.
Here, the viscosity of the release layer forming composition is determined by using a commercially available liquid viscosity measuring viscometer, for example, referring to the procedure described in JIS K7117-2, and the temperature of the release layer forming composition. It can be measured under the condition of 25 ° C. Preferably, a conical flat plate type (cone plate type) rotational viscometer is used as the viscometer, and 1 ° 34'x R24 is preferably used as the standard cone rotor in the same type of viscometer to form a release layer. It can be measured under the condition that the temperature of the object is 25 ° C. Examples of such a rotational viscometer include TVE-25H manufactured by Toki Sangyo Co., Ltd.

The composition of the present invention may contain various components in addition to the polyamic acid and the organic solvent. For example, a cross-linking agent (hereinafter, also referred to as a cross-linking compound) can be mentioned, but the present invention is not limited thereto.

Examples of the crosslinkable compound include a compound containing two or more epoxy groups, a melamine derivative, a benzoguanamine derivative or glycoluryl having a group in which the hydrogen atom of the amino group is substituted with a methylol group, an alkoxymethyl group or both. However, the present invention is not limited to these.

Specific examples of the crosslinkable compound are given below, but the present invention is not limited thereto.
Examples of the compound containing two or more epoxy groups include cyclohexene structures such as Epolide GT-401, Epolide GT-403, Epolide GT-301, Epolide GT-302, Celoxide 2021, and Celoxide 3000 (all manufactured by Daicel Co., Ltd.). Epoxy compounds possessed; Epicoat 1001, Epicoat 1002, Epicoat 1003, Epicoat 1004, Epicoat 1007, Epicoat 1009, Epicoat 1010, Epicoat 828 (above, manufactured by Japan Epoxy Resin Co., Ltd. (currently manufactured by Mitsubishi Chemical Co., Ltd., jER®) Bisphenol A type epoxy compound such as (series)); Bisphenol F type epoxy compound such as Epicoat 807 (manufactured by Japan Epoxy Resin Co., Ltd.); Epicoat 152, Epicoat 154 (all manufactured by Japan Epoxy Resin Co., Ltd. (currently: Mitsubishi Chemical Co., Ltd.) , JER (registered trademark) series)), EPPN201, EPPN202 (all manufactured by Nippon Kayaku Co., Ltd.) and other phenol novolac type epoxy compounds; ECON-102, ECON-103S, ECON-104S, ECON-1020, ECON- Cresol novolac type epoxy compounds such as 1025, ECON-1027 (all manufactured by Nippon Kayaku Co., Ltd.), Epicoat 180S75 (manufactured by Japan Epoxy Resin Co., Ltd. (currently Mitsubishi Chemical Co., Ltd., jER (registered trademark) series)); Naphthalene type epoxy compounds such as V8000-C7 (manufactured by DIC Co., Ltd.); Denacol EX-252 (manufactured by Nagase ChemteX Corporation), CY175, CY177, CY179, Araldite CY-182, Araldite CY-192, Araldite CY-184 ( Above, BASF), Epicron 200, Epicron 400 (above, DIC Co., Ltd.), Epicoat 871, Epicoat 872 (above, Japan Epoxy Resin Co., Ltd. (currently: Mitsubishi Chemical Co., Ltd., jER (registered trademark) series) )), ED-5661, ED-5662 (all manufactured by Ceranies Coating Co., Ltd.) and other alicyclic epoxy compounds; Denacol EX-611, Denacol EX-612, Denacol EX-614, Denacol EX-622, Denacol EX -411, Denacol EX-512, Denacol EX-522, Denacol EX-421, Denacol EX-313, Denacol EX-314, Denacol EX-312 (above, Nagasechem) Examples thereof include aliphatic polyglycidyl ether compounds (manufactured by TEX Co., Ltd.).

As a melamine derivative, a benzoguanamine derivative or glycoluryl having a group in which the hydrogen atom of the amino group is substituted with a methylol group, an alkoxymethyl group or both, an average of 3.7 methoxymethyl groups are substituted per triazine ring. MX-750, MW-30 in which an average of 5.8 methoxymethyl groups are substituted per triazine ring (all manufactured by Sanwa Chemical Co., Ltd.); Cymel 300, Cymel 301, Cymel 303, Cymel 350, Methyl methmethylated melamines such as Cymel 370, Cymel 771, Cymel 325, Cymel 327, Cymel 703, Cymel 712; Butoxymethylated melamines such as Cymel 506, Cymel 508; carboxy group-containing methoxymethylated isobutoxymethylated melamines such as Cymel 1141; methoxymethylated ethoxymethylated benzoguanamines such as Cymel 1123; Methyl methoxymethylated butoxymethylated benzoguanamine; butoxymethylated benzoguanamine such as Cymel 1128; carboxy group-containing methoxymethylated ethoxymethylated benzoguanamine such as Cymel 1125-80; butoxymethylated glycol uryl such as Cymel 1170; Examples thereof include methylolated glycol uryl (above, manufactured by Mitsui Sianamid Co., Ltd. (currently Nippon Cytec Industries Co., Ltd.)).

By applying the composition for forming a release layer of the present invention described above to a substrate and heating it, a thin film (release layer) made of polyimide having high heat resistance, appropriate flexibility, and an appropriate coefficient of linear expansion. Can be obtained.

Examples of the base substrate (base material) include glass, plastic (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene resin, etc.), metal (silicon wafer, etc.). , Wood, paper, slate, etc.

The method of coating is not particularly limited, but for example, a cast coating method, a spin coating method, a blade coating method, a dip coating method, a roll coating method, a bar coating method, a die coating method, an inkjet method, and a printing method (projection printing method). , Intaglio, lithographic, screen printing, etc.).

Further, as a method for imidizing the polyamic acid contained in the composition for forming a release layer of the present invention, thermal imidization in which the composition applied on the substrate is heated as it is, and heating by adding a catalyst to the composition are performed. Catalytic imidization can be mentioned.

In the catalytic imidization of polyamic acid, a catalyst is added to the composition for forming a release layer of the present invention, the catalyst-added composition is prepared by stirring, and then applied to a substrate and heated to form a resin thin film (release layer). ) Is obtained. The amount of catalyst is 0.1 to 30 mol times, preferably 1 to 20 mol times, of the amic acid group. Further, acetic anhydride or the like can be added as a dehydrating agent to the catalyst-added composition, and the amount thereof is 1 to 50 mol times, preferably 3 to 30 mol times, that of the amic acid group.

It is preferable to use a tertiary amine as the imidization catalyst. As the tertiary amine, pyridine, substituted pyridines, imidazole, substituted imidazoles, picoline, quinoline, isoquinoline and the like are preferable.

The heating temperature during thermal imidization and catalytic imidization is preferably 450 ° C. or lower. If the temperature exceeds 450 ° C., the obtained resin thin film becomes brittle, and it may not be possible to obtain a resin thin film suitable for the intended use.
Further, considering the heat resistance and the coefficient of linear expansion characteristics of the obtained resin thin film, the applied composition is heated at 50 ° C. to 100 ° C. for 5 minutes to 2 hours, and then the heating temperature is gradually increased as it is to finalize. It is desirable to heat at more than 375 ° C. to 450 ° C. for 30 minutes to 4 hours.
In particular, the applied composition is heated at 50 ° C. to 100 ° C. for 5 minutes to 2 hours, then over 100 ° C. to 200 ° C. for 5 minutes to 2 hours, and then at over 200 ° C. to 375 ° C. for 5 minutes to 2 hours. Finally, it is preferable to heat at 375 ° C. to 450 ° C. for 30 minutes to 4 hours.
Examples of the appliance used for heating include a hot plate and an oven. The heating atmosphere may be under air or an inert gas, and may be under normal pressure or reduced pressure.

The thickness of the resin thin film is usually about 0.01 to 10 μm, preferably about 0.05 to 5 μm, particularly when used as a release layer, and the thickness of the coating film before heating is adjusted to obtain a desired thickness. Form a resin thin film.

The thin film described above is most suitable for use as a release layer for peeling a substrate applied to a flexible electronic device without damaging it.

The composition of the present application can form a release layer provided between a flexible substrate applied to a flexible electronic device and a base substrate. The base substrate preferably contains glass or a silicon wafer, and more preferably contains glass.

For example, a release layer can be formed by applying the composition of the present application to a glass substrate by a conventionally known method and heating the obtained coating film at a predetermined temperature.
In addition, the body layer to be peeled can be formed on the peeled layer. The peeled body layer may be one layer or a plurality of layers. In order to fabricate various devices, it is realistic to have a plurality of layers.
Of the layers to be peeled, the layer directly above the peeling layer depends on the peeling layer to be used, but it is preferable to use one having good peelability with the peeling layer, in other words, one having poor adhesion with the peeling layer to be used. Good.

As another aspect of the present application, a method for producing a material to be peeled is provided.
The method is
a) A step of forming a release layer after applying the composition of the present application on a glass substrate;
b) A step of forming a body to be peeled on the peeled layer; and c) A step of peeling the body to be peeled at the interface between the peeled layer and the body to be peeled;
By having the above, a stripped body can be obtained.
b) In the step, the "exfoliated body" may be one layer or a plurality of layers. The layer immediately above the peeling layer of the "exfoliated body" depends on the peeling layer used, but has good peelability with the peeling layer, in other words, has poor adhesion with the peeling layer used. It is good to have it.

According to another preferred embodiment of the present invention, the substrate structure is applied to a flexible electronic device.
With the base board
A release layer that covers the base substrate in one or more regions and is formed by the release layer forming composition according to the present invention.
A flexible substrate that covers the base substrate and the release layer.
Provided is a substrate structure characterized in that the adhesion between the flexible substrate and the release layer is larger than the adhesion between the release layer and the base substrate. The magnitude of the adhesion force referred to here can be confirmed by, for example, the cross-cut test shown in the examples of the present application.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

The abbreviations used in this embodiment are listed and described below.
<Solvent>
NMP: N-methylpyrrolidone.
<Amines>
p-PDA: p-phenylenediamine.
APAB: 2- (3-aminophenyl) -5-aminobenzimidazole.
DATP: 4,4'-diamino-p-terphenyl.
6FAP: 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane.

<Acid dianhydride>
BPDA: 3,3'-4,4'-biphenyltetracarboxylic dianhydride.
BA-TME: 4,4-biphenylene bis (trimellitic acid monoesteric anhydride).
PMDA: Pyromellitic acid dianhydride.
<Aldehyde>
IPHA: Isophthalaldehyde.

[Measurement of number average molecular weight and weight average molecular weight]
The weight average molecular weight (hereinafter abbreviated as "Mw") and the molecular weight distribution of the polymer were determined by using a GPC apparatus (Shodex (registered trademark) columns KF803L and KF805L) manufactured by Nippon Kogaku Co., Ltd. The measurement was carried out under the condition of a temperature of 50 ° C. In addition, Mw was a polystyrene conversion value.

<Synthesis example>
<Synthesis Example 1 Synthesis of Polyimide Precursor P1>
BPDA (98) // p-PDA (90) / DATP (10)
17.8 g (0.164 mol) of p-PDA, 2.38 g (0.009 mol) of DATP, and 2.05 g (0.009 mol) of APAB were dissolved in 425 g of NMP, and 52.8 g (0.179 mol) of BPDA. After adding moles) at the same time, 7.4 g of NMP was added again, and the mixture was reacted at 23 ° C. for 24 hours in a nitrogen atmosphere. The Mw of the obtained polyimide precursor P1 was 63000 and the molecular weight distribution was 9.9.

<Synthesis Example 2 Synthesis of Polyimide Precursor P2>
BPDA (98) / DATP (100)
30.8 g (0.118 mol) of DATP was dissolved in 425 g of NMP, 34.1 g (0.116 mol) of BPDA was added at the same time, 10 g of NMP was added again, and the reaction was carried out in a nitrogen atmosphere at 23 ° C. for 24 hours. I let you. The Mw of the obtained polyimide precursor P2 was 70,700 and the molecular weight distribution was 9.7.

<Synthesis Example 3 Synthesis of Polyimide Precursor P3>
PMDA (98) / p-PDA (80) / DATP (20)
20.261 g (0.1875 mol) of p-PDA and 12.206 g (0.0469 mol) of TPDA were dissolved in 617.4 g of NMP, cooled to 15 ° C., and then 50.112 g (0.2298 mol) of PMDA was added. Then, the reaction was carried out at 50 ° C. for 48 hours in a nitrogen atmosphere. The Mw of the obtained polyimide precursor P3 was 82,100, and the molecular weight distribution was 2.7.

<Synthesis Example 4 Synthesis of Polyimide Precursor P4>
BP-TME (98) // p-PDA (95) / APAB (5)
9.66 g (0.089 mol) of p-PDA and 1.05 g (0.005 mol) of APAB were dissolved in 440 g of NMP, 49.2 g (0.092 mol) of BP-TME was added, and under a nitrogen atmosphere, The reaction was carried out at room temperature for 24 hours. The Mw of the obtained polyimide precursor P4 was 57,000, and the molecular weight distribution was 9.3.

<Synthesis Example 5 Synthesis of Polyimide Precursor P5>
BPDA (98) // p-PDA (100)
3.176 g (0.02937 mol) of p-PDA was dissolved in 88.2 g of NMP, 8.624 g (0.02931 mol) of BPDA was added, and the mixture was reacted at 23 ° C. for 24 hours under a nitrogen atmosphere. The Mw of the obtained polyimide precursor P5 was 107,300 and the molecular weight distribution was 4.6.

<Synthesis Example 6 Synthesis of Polybenzoxazole Precursor (P6)>
IHPA (98) // 6FAP (100)
3.18 g (0.059 mol) of 6FAP was dissolved in 70 g of NMP, 7.92 g (0.060 mol) of IPHA was added, and the mixture was reacted at 23 ° C. for 24 hours under a nitrogen atmosphere. The Mw of the obtained polymer was 107,300 and the molecular weight distribution was 4.6.

<Synthesis Example 7 Synthesis of Polyimide Precursor P7>
PMDA (98) // p-PDA (100)
10.078 g (93 mmol) of p-PDA was dissolved in 220.0 g of NMP. To the obtained solution, 19.922 g (91 mmol) of PMDA was added, and the mixture was reacted at 23 ° C. for 24 hours under a nitrogen atmosphere. The Mw of the obtained polymer was 55,900 and the molecular weight distribution was 3.1.

<Preparation of release layer substrate>
P1 to P7 obtained in Synthesis Examples 1 to 7 above are diluted to 4 wt% with NMP, applied on a 100 mm × 100 mm glass substrate (OA-10G non-alkali glass) or a silicon wafer using a spin coater, and then cured. Under conditions A to C, a release layer was prepared by firing in an oven.
Cure condition A : Maintain at 120 ° C for 30 minutes → temperature rise → maintain at 300 ° C for 60 minutes → temperature rise → maintain at 400 ° C for 60 minutes. The rate of temperature rise was 10 ° C./min.
Cure condition B : Maintain at 120 ° C for 30 minutes → Temperature rise → Maintain at 180 ° C for 20 minutes → Temperature rise → Maintain at 240 ° C for 20 minutes → Temperature rise → Maintain at 300 ° C for 20 minutes → Temperature rise → Maintain at 400 ° C for 20 minutes → Temperature rise → Maintain at 450 ° C for 60 minutes. The rate of temperature rise was 10 ° C./min.
Cure condition C : Maintain at 80 ° C for 10 minutes → Temperature rise → Maintain at 300 ° C for 30 minutes → Temperature temperature → Maintain at 400 ° C for 30 minutes. The rate of temperature rise was 10 ° C./min.

The film thickness of the obtained coating film was measured using a contact-type film thickness measuring device (Dektak 3ST manufactured by ULVAC, Inc.).
Table 1 shows the precursors of P1 to P7 used, the coating substrate, the curing conditions, and the film thickness of the prepared release layer.

<Crosscut test I>
With respect to the substrates provided with the release layers of Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1, the adhesion of the substrate (glass or silicon wafer) / release layer was confirmed by the cross-cut test I.
The cross-cut test I was performed as follows.
(1) 100 1 mm square squares were prepared on the film.
(2) After that, the above square was attached with an adhesive tape (cellotape (registered trademark)), and a peeling step was performed.
(3) The above squares remaining on the substrate after the peeling step were counted.

<Indicator of the result of cross-cut test I>
As a result of the cross-cut test, the degree of peeling is shown by the following index.
5B: No peeling.
4B: Peeling of 5% or less.
3B: 5 to 15% peeling.
2B: 15-35% peeling.
1B: 35-65% peeling.
0B: 65% to 80% peeling.
B: 80% to 95% peeling.
A: 95% to less than 100% peeling.
AA: 100% peeling.

Apart from the cross-cut test I, with respect to the substrates provided with the release layer of Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1, the characteristics of the components constituting the release layer, that is, (1) when heated. The temperature showing a 1% weight loss in the weight change, (2) the refractive index at a wavelength of 1000 nm, (3) birefringence at a wavelength of 1000 nm, and (4) surface energy were measured. The measurement conditions for each characteristic are shown below.

<(1) Temperature showing 1% weight loss due to weight change during heating>
Thermogravimetric (TG) measurement was performed in a nitrogen atmosphere using a TD-DTA2000ST manufactured by Bruker Co., Ltd. to determine a temperature at which the weight was reduced by 1%.

<(2) Refractive index at wavelength 1000 nm and (3) Birefringence>
The refractive index and birefringence were measured using a high-speed spectroscopic ellipsometer M-2000 (manufactured by JA Woolam Japan Co., Ltd.). The refractive index was defined as an in-plane refractive index with a value of 1000 nm, and the birefringence was defined as the difference between the in-plane refractive index and the out-of-plane refractive index.

<(4) Surface energy>
The surface energy of each member was measured using a fully automatic contact angle meter DM-701 (manufactured by Kyowa Interface Science Co., Ltd.). The solvents used for the measurement were water and methylene iodide, which were calculated from the contact angles of these solvents.

<Formation of the material to be peeled and its peeling test (cross-cut test II)>
The material to be peeled was formed on the substrate provided with the peeling layer of Examples 1 to 5 and Comparative Examples 1 to 3, and the degree of peeling was confirmed by the cross-cut test II.

<< Preparation of layer to be peeled >>
A polyimide layer was formed as a material to be peeled off on the peeled layer of the substrate provided with the peeled layer.
Specifically, the precursor P5 obtained in the above Synthesis Example 5 or Synthesis Example 1 is placed on the release layer of the substrate provided with the release layer of Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1. Alternatively, P1 was applied with a bar coater. After that, maintain at 120 ° C for 30 minutes in the oven → temperature rise → maintain at 180 ° C for 20 minutes → temperature rise → maintain at 240 ° C / 20 minutes → temperature rise → maintain at 300 ° C for 20 minutes → temperature rise → maintain at 400 ° C for 20 minutes Curing was performed at maintenance → temperature rise → maintenance at 450 ° C. for 60 minutes (the rate was 10 ° C./min at any temperature rise) to prepare a body layer to be peeled with a thickness of 15 μm made of polyimide.

<< Crosscut Test II >>
With respect to the substrate provided with the peeled body layer and the peeled layer obtained above, the adhesion between the peeled body layer / the peeled layer was confirmed by the cross-cut test II.
The cross-cut test II was performed in the same manner as the cross-cut test I.
Table 2 shows (1) a temperature indicating a 1% weight loss due to a weight change during heating (indicated by "(1)" in Table 2), and (2) a refractive index at a wavelength of 1000 nm (in Table 2, " (2) ”), (3) Difference between the refractive index and birefringence of (2) (indicated by“ (3) ”in Table 2), (4) Surface energy (in Table 2, It is expressed by "(4)". However, the unit is dyne / cm), the polyimide precursor used in the layer to be stripped, and the results of the cross-cut tests I and II are shown.

*: The birefringence of Comparative Example 2 could not be measured.
**: The cross-cut test II of Comparative Example 1 and Comparative Example 3 could not be measured because the adhesion between the release layer and the substrate was low.

The following can be seen from Table 2. In the peeling layers of Examples 1 to 5, since the result of Test I was 5B, the peeling layer did not peel off from the substrate, while the result of Test II was AA, so that the peeling layer was separated from the peeled body layer. It can be seen that only peels off. In short, it can be seen that the release layer formed from the release layer composition of the present invention provides the desired release result.
On the other hand, in Comparative Example 1 and Comparative Example 3, since the result of Test I is AA, it can be seen that the peeling layer is peeled from the substrate. In short, it can be seen that Comparative Example 1 and Comparative Example 3 cannot obtain the desired peeling result. Further, in Comparative Example 2, since both Test I and Test II were 5B, the peeling did not occur at the interface between the peeling layer and the substrate and at the interface between the peeling layer and the material layer to be peeled, and the desired peeling result was obtained. It turns out that you cannot get.

Claims (11)

A composition for forming a release layer, which comprises a polyamic acid having a weight average molecular weight of 10,000 or more and a monomer unit represented by the following formula (1) in an amount of 50 mol% or more and an organic solvent.
A composition for forming a release layer, wherein the polyamic acid further contains a monomer unit represented by the following formula (2).

[In the formula, X ¹ represents a tetravalent organic group, and Y ¹ represents a divalent group represented by the following formula (P):

(In the formula, R represents F, Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group, m represents an integer of 0 to 4, and r represents an integer of 1 to 4)]

[During the ceremony,
X ¹ is as defined above and Y ² represents the group represented by the following equation (P4):

(During the ceremony,
R ⁷ and R ⁸ may be the same or different, and represent F, Cl, an alkyl group having 1 to 3 carbon atoms, or a phenyl group.
R'represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a phenyl group.
l represents an integer from 0 to 4, and m is as defined above)]. The composition for forming a release layer according to claim 1 , wherein X ¹ is a tetravalent aromatic group. The composition according to claim 2 , wherein the tetravalent aromatic group has at least one selected from a benzene skeleton, a naphthalene skeleton and a biphenyl skeleton. The composition according to any one of claims 1 to 3 , wherein the organic solvent is a solvent represented by the following formula (A) or (B).

(In the formula, ^Ra and R ^b may be the same or different, and represent an alkyl group having 1 to 4 carbon atoms, and h represents a natural number). The composition for forming a release layer according to any one of claims 1 to 4 , wherein the content of the monomer unit represented by the formula (1) in the polyamic acid is 60 mol% or more. The composition for forming a release layer according to any one of claims 1 to 5 , in order to form a release layer provided directly above the glass substrate. A release layer formed between a flexible substrate applied to a flexible electronic device and a base substrate.
A release layer prepared by using the composition for forming a release layer according to any one of claims 1 to 6 . A board structure applied to flexible electronic devices.
With the base board
A release layer that covers the base substrate in one or more regions and is formed by the release layer forming composition according to any one of claims 1 to 6 .
A flexible substrate that covers the base substrate and the release layer.
A substrate structure characterized in that the adhesion between the release layer and the base substrate is larger than the adhesion between the flexible substrate and the release layer. The substrate structure according to claim 8 , wherein the base substrate includes glass. A method for producing a release layer, which comprises using the composition for forming a release layer according to any one of claims 1 to 6 . A method for manufacturing a substrate structure applied to flexible electronic devices.
The process of preparing the base board,
A step of producing a release layer covering the base substrate in one or more regions using the release layer forming composition according to any one of claims 1 to 6 .
A step of forming a flexible substrate on the base substrate and the release layer is included.
A manufacturing method, characterized in that the adhesion between the release layer and the base substrate is greater than the adhesion between the flexible substrate and the release layer.