WO2019142866A1

WO2019142866A1 - Polyimide precursor resin composition

Info

Publication number: WO2019142866A1
Application number: PCT/JP2019/001296
Authority: WO
Inventors: 昌樹米谷; 直志篠原; 慶太小川; 隆行金田; 敏章奥田
Original assignee: 旭化成株式会社
Priority date: 2018-01-17
Filing date: 2019-01-17
Publication date: 2019-07-25
Also published as: CN111479854B; KR20200044950A; CN111479854A; JPWO2019142866A1; JP2022167930A; KR102417292B1; KR102650759B1; TWI814769B; TW201932509A; KR20220098403A

Abstract

This resin composition contains a solvent and a polyimide precursor having the structure represented by formula (1) {in the formula, R₁represents a divalent organic group and, when there is a plurality thereof, the R1's independently represent divalent organic groups; R₂ represents a tetravalent organic group and, when there is a plurality thereof, the R2's independently represent tetravalent organic groups; n is a positive integer.}, wherein the weight average molecular weight of the polyimide precursor is 110,000 to 250,000 and the solids content of the resin composition is 10-25 mass%_.

Description

Polyimide precursor resin composition

The present invention relates to a resin composition containing a polyimide precursor, and a polyimide film. The invention further relates to flexible devices (e.g. flexible displays) and laminates and methods of making them.

Polyimide resins are insoluble and infusible super heat-resistant resins, and have excellent heat resistance properties (for example, heat oxidation 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. Examples of application of the polyimide resin in the field of electronic materials include, for example, an insulating coating material, an insulating film, a semiconductor, an electrode protective film of a thin film transistor liquid crystal display (TFT-LCD), and the like. Recently, in place of the glass substrate conventionally used in the field of display materials, adoption of a flexible substrate utilizing its lightness and flexibility has been considered.

For example, Patent Document 1 discloses a resin precursor (weight-average molecular weight 30,000 to 90,000) which is polymerized from bis (diaminodiphenyl) sulfone (hereinafter also referred to as DAS) and has a siloxane unit, and the precursor is cured The polyimide obtained by this method has low residual stress generated with a support such as glass, is excellent in chemical resistance, and influences the yellowness (YI) value and the total light transmittance by the oxygen concentration at the curing step. It is stated that is small. Patent Document 2 describes a resin composition comprising a polyimide precursor of a specific absorbance and an alkoxysilane compound of a specific absorbance, which is obtained by curing the resin composition. It is described that the resin to be prepared has both sufficient adhesiveness with the support and releasability by laser exfoliation and the like.

International Publication No. 2014/148441 International Publication No. 2016/167296

When a transparent polyimide resin is to be applied to a flexible substrate, a resin composition containing a polyimide precursor is coated on a substrate such as glass to form a coating, which is then dried by heating, and further a polyimide precursor Is imidized to form a polyimide film, and if necessary, a device is formed on the film, and then the film is peeled off from a glass substrate as a support to obtain the desired product.

In recent years, with the increase in size of a display or the like, which is an application of a flexible substrate, when a composition containing a polyimide precursor is applied to a substrate such as glass, a slit coater may be used. When a composition is applied by a slit coater to form a coating film, a coater gap (a set value for defining the distance between a glass substrate and a slit nozzle) is provided as a parameter that affects the coating film. If the size is small, the nozzle may come in contact with the substrate when the flatness of the glass substrate is poor, and the slit nozzle may be broken. In particular, with the recent increase in size of displays and the like, it has become necessary to make the coater gap sufficiently large.
When a polyimide film is used as a material of a screen of a flexible display or the like, since the wavelength of visible light is about 380 nm to about 700 nm, in order to obtain good optical performance, particularly high film thickness uniformity is required. Be

When the inventors evaluated the coating of the slit coat using a polyimide precursor having a molecular weight and a skeleton similar to those described in Patent Documents 1 and 2, it was found that the above-mentioned characteristics were insufficient. I found it. Accordingly, an object of the present invention is to provide a polyimide precursor-containing resin composition which is excellent in coating properties of slit coat and also in mechanical properties and optical properties required for applications such as flexible substrates. .

As a result of intensive investigations, the present inventors have found that using a polyimide precursor having a specific structure leads to the realization of good coating properties in slit coat and good mechanical and optical properties. .
That is, the present invention includes the following aspects.
[1] The following formula (1):

In the formula, when there are a plurality of R _{1 's} each independently represent a divalent organic group, and when there are a plurality of R _{2' s} each represent a tetravalent organic group independently, n is a positive integer. A resin composition comprising a polyimide precursor having a structure represented by
The weight average molecular weight of the polyimide precursor is 110,000 to 250,000,
A resin composition, wherein the solid content of the resin composition is 10 to 25% by mass.
[2] The shear rate dependency (TI) represented by the following formula is 0.9 to 1.1 when the viscosity of the resin composition is measured at 23 ° C. with a temperature controlled viscometer The resin composition according to the above aspect 1.
TI = ηa / ηb
{Wherein ηa (mPa · s) is the viscosity at the measured rotational speed a (rpm) of the resin composition, and ηb (mPa · s) is the viscosity at the measured rotational speed b (rpm) of the resin composition, However, it is a * 10 = b. }
[3] The resin composition according to the above aspect 1 or 2, wherein the resin composition is a resin composition for slit coat.
[4] At least one of R ₁ in the formula (1) is a group represented by the following formula (2):

The resin composition according to any one of the above embodiments 1 to 3, which is a group represented by
[5] The polyimide precursor has the following formula (3):

[Wherein, each of R ₃ and R ₄ independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a monovalent aromatic group having 6 to 10 carbon atoms, when there are a plurality of each. , And m is an integer of 1 to 200. ] The resin composition according to any one of the above aspects 1 to 4, which has a structure represented by
[6] The resin composition according to any one of the above Embodiments 1 to 5, wherein the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride containing pyromellitic dianhydride and diamine.
[7] The above aspects 1 to 6, wherein the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride containing 3,3 ′, 4,4′-biphenyltetracarboxylic acid dianhydride and diamine The resin composition as described in any one.
[8] The polyimide precursor is a copolymer of tetracarboxylic dianhydride and diamine, and the tetracarboxylic dianhydride is pyromellitic dianhydride and 3,3 ′, 4,4 ′. -Biphenyltetracarboxylic acid dianhydride at a molar ratio of 20:80 to 80:20 of the pyromellitic acid dianhydride and the 3,3 ′, 4,4′-biphenyltetracarboxylic acid dianhydride, The resin composition according to any one of the above embodiments 1 to 7.
[9] The polyimide precursor is tetracarboxylic acid dianhydride, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 2,2′-bis (trifluoromethyl) benzidine and 9, 9. The resin composition according to any one of the above aspects 1 to 8, which is a copolymer with one or more diamines selected from the group consisting of 9-bis (4-aminophenyl) fluorene.
[10] The resin composition according to any one of the above embodiments 1 to 9, wherein the weight average molecular weight of the polyimide precursor is 160,000 to 220,000.
[11] The resin composition according to any one of the above embodiments, which is a resin composition for a flexible device.
[12] The resin composition according to any one of the above embodiments 1 to 11, wherein the resin composition is a resin composition for a flexible display.
[13] A polyimide film which is a cured product of the resin composition according to any one of the above embodiments 1 to 12.
[14] The polyimide film according to the above aspect 13, wherein retardation in a thickness direction (Rth) in terms of a film thickness of 10 μm is 300 or less and / or a yellowness (YI) in terms of a film thickness of 10 μm is 20 or less .
[15] A flexible device comprising the polyimide film according to the above-mentioned aspect 13 or 14.
[16] A flexible display comprising the polyimide film according to the above-mentioned aspect 13 or 14.
[17] The flexible display according to the above-mentioned aspect 16, wherein the polyimide film is disposed at a place to be viewed when the flexible display is observed from the outside.
[18] a coating step of coating the resin composition according to any one of the above embodiments 1 to 12 on the surface of a support;
A film forming step of heating the resin composition to form a polyimide film;
And a peeling step of peeling the polyimide film from the support.
[19] The method for producing a polyimide film according to the above-mentioned aspect 18, wherein the applying step comprises slit-coating the resin composition.
[20] At least one of R ₁ in the formula (1) is a group represented by the following formula (2):

The method for producing a polyimide film according to the above-mentioned aspect 19, which is a group represented by
[21] The polyimide precursor is represented by the following formula (3):

[Wherein, each of R ₃ and R ₄ independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a monovalent aromatic group having 6 to 10 carbon atoms, when there are a plurality of each. , And m is an integer of 1 to 200. ] The manufacturing method of the polyimide film of said 19 or 20 which has a structure represented by}.
[22] The method for producing a polyimide film according to any one of the above embodiments 18 to 21, further comprising an irradiation step of irradiating a laser onto the polyimide film from the support side prior to the peeling step.
[23] a coating step of coating the resin composition according to any one of the above embodiments 1 to 12 on the surface of a support;
A film forming step of heating the resin composition to form a polyimide film;
An element forming step of forming an element on the polyimide film;
And a peeling step of peeling the polyimide film on which the element is formed from the support.
[24] The method for producing a display according to the above-mentioned aspect 23, wherein the applying step comprises slit-coating the resin composition.
[25] The method for producing a display according to the above-mentioned aspect 23 or 24, wherein the polyimide film is disposed at a position which is visually recognized when the display is observed from the outside.

According to one aspect of the present invention, it is possible to provide a polyimide precursor-containing resin composition which is excellent in coating properties in slit coating and also excellent in mechanical properties and optical properties required for applications such as flexible substrates.

It is a figure which shows the structure of the polyimide substrate top of the top emission type flexible organic electroluminescent display as an example of the display provided by 1 aspect of this invention.

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.

In the present embodiment,
Following formula (1):

In the formula, when there are a plurality of R _{1 's} each independently represent a divalent organic group, and when there are a plurality of R _{2' s} each represent a tetravalent organic group independently, n is a positive integer. }
The resin composition containing the polyimide precursor which has a structure represented by these is provided. In one aspect, the resin composition comprises the polyimide precursor and a solvent.

In a preferred embodiment, at least one of R ₁ in formula (1) is a group of the following formula (2):

Is a group represented by

That at least one of R ₁ in the formula (1) is a structure represented by the formula (2) contributes to good optical properties (especially Rth) and heat resistance of the polyimide which is a cured product of the polyimide precursor . In one embodiment, all of the n R _{1 s in} Formula (1) have a structure represented by Formula (2). In one aspect, the ratio of the structure represented by Formula (2) to n R ₁ in Formula (1) may be 0% or more, 10% or more, or 20% or more. It may be 100% or less, or 90% or less.

The embodiment is also a resin composition containing a polyimide precursor having a structure represented by the above formula (1), wherein the polyimide which is a cured product of the resin composition has a thickness direction retardation (Rth) 300. Also provided is a resin composition having the following and / or a yellowness (YI) of 20 or less. The above low thickness direction retardation (Rth) indicates that the polyimide has low birefringence, and the above low yellowness (YI) indicates that the polyimide has a good color tone (that is, it is almost colorless) It represents that it is.

The resin composition of the present embodiment preferably has an excellent slit coat performance and gives a polyimide film having excellent mechanical properties and optical properties, so it is preferably for flexible devices (for example, for flexible substrates), particularly preferably It is useful for flexible displays.

(Weight average molecular weight of polyimide precursor)
In one aspect, the weight average molecular weight of the polyimide precursor is 110,000 or more and 250,000 or less. The present inventor found that the weight average molecular weight of the polyimide precursor greatly affects the coating performance when using the resin composition of the present embodiment for slit coating, and has conducted intensive studies. As a result, when the weight average molecular weight of the polyimide precursor is 110,000 or more, the solid content of the resin composition can be adjusted to realize a good slit coat, while the weight average molecular weight is 250,000 or less The polyimide precursor is found to be easy to manufacture. That is, in the present embodiment, the weight average molecular weight of the polyimide precursor is 110,000 or more in terms of coating performance, and 250,000 or less in terms of ease of manufacture.

The desired weight average molecular weight of the polyimide precursor may vary depending on the desired application, the type of polyimide precursor, the solid content of the resin composition, the type of solvent that the resin composition may contain, and the like.

For example, preferable examples of the lower limit of the weight average molecular weight are 111,000, 112,000, 113,000, 114,000, 115,000, 116,000, 117,000, 118,000, 119,000, 120, 90, 120. 000, 121,000, 122,000, 123,000, 124,000, 125,000, 126,000, 127,000, 128,000, 129,000, 130,000, 131,000, 132,000, 133,000, 134,000, 135,000, 136,000, 137,000, 138,000, 139,000, 140,000, 141,000, 142,000, 143,000, 144,000, 145, 000, 146,000, 147,000, 148,000, 149,00 , 150,000, 151,000, 152,000, 153,000, 154,000, 155,000, 156,000, 157,000, 158,000, 159,000, 160,000, 161,000, 162 000, 163,000, 164,000, 165,000, 166,000, 167,000, 168,000, 169,000, 170,000, 171,000, 172,000, 173,000, 174,000 , 175,000, 176,000, 177,000, 178,000, 179,000, 180,000, 181,000, 182,000, 183,000, 184,000, 185,000, 186,000, 187 , 188,000, 189,000, 190,000, 191 000, 192,000, 193,000, 194,000, 195,000, 196,000, 197,000, 198,000, 19,000, 200,000, 201,000, 202,000, 203,000, 204,000, 205,000, 206,000, 207,000, 208,000, 209,000, 210,000, 211,000, 212,000, 213,000, 214,000, 215,000, 216, 000, 217,000, 218,000, 219,000, 220,000, 221,000, 222,000, 223,000, 224,000, 225,000, 226,000, 227,000, 228,000, 229,000, 230,000, 231,000, 232,000, 2 33,000, 234,000, 235,000, 236,000, 237,000, 238,000, 239,000, 240,000, 241,000, 242,000, 243,000, 244,000, 245, 000, 246,000, 247,000, 248,000, or 249,000.

Also, preferable examples of the upper limit of the weight average molecular weight are 249,000, 248,000, 247,000, 246,000, 245,000, 244,000, 243,000, 242,000, 241,000, 240, 240. 000, 239,000, 238,000, 237,000, 235,000, 234,000, 233,000, 232,000, 231,000, 230,000, 229,000, 228,000, 227,000, 226,000, 225,000, 224,000, 223,000, 222,000, 221,000, 220,000, 219,000, 218,000, 217,000, 216,000, 215, 000, 214,000, 213,000, 212,000, 211,000 210,000, 209,000, 208,000, 207,000, 206,000, 205,000, 204,000, 203,000, 202,000, 201,000, 200,000, 19,000, 198, 000, 197,000, 196,000, 195,000, 194,000, 193,000, 192,000, 191,000, 190,000, 189,000, 188,000, 187,000, 186,000, 185,000, 184,000, 183,000, 182,000, 181,000, 180,000, 179,000, 178,000, 177,000, 176,000, 175,000, 174,000, 173, 000, 172,000, 171,000, 170,000, 169, 00, 168,000, 167,000, 166,000, 165,000, 164,000, 163,000, 162,000, 161,000, 160,000, 159,000, 158,000, 157,000, 156,000, 155,000, 154,000, 153,000, 152,000, 151,000, 150,000, 149,000, 148,000, 147,000, 146,000, 145,000, 144, 000, 143,000, 142,000, 141,000, 140,000, 139,000, 138,000, 137,000, 136,000, 135,000, 134,000, 133,000, 132,000, 131,000, 130,000, 129,000, 128,000, 12 7,000, 126,000, 125,000, 124,000, 123,000, 122,000, 121,000, 120,000, 119,000, 118,000, 117,000, 116,000, 115, 000, 114,000, 113,000, 112,000, or 111,000.

For example, in view of elongation and yellowness (YI) of a cured product of a resin composition containing a polyimide precursor (for example, a polyimide film (also referred to as a cured film in the present disclosure)), a weight average molecular weight of 120,000 or more is preferable 130,000 or more is more preferable, and 160,000 or more is particularly preferable. Moreover, in the viewpoint of the haze of the said hardened | cured material (for example, polyimide film), 220,000 or less is preferable and 200,000 or less is more preferable. In a preferred embodiment, the weight average molecular weight of the polyimide precursor is 160,000 or more and 220,000 or less.

(Retardation in the thickness direction of polyimide film (Rth))
When a polyimide film is produced as a cured product of a polyimide precursor (that is, imidized), retardation in the thickness direction (Rth) at a film thickness of 10 μm of the polyimide film varies depending on the monomer skeleton of the polyimide precursor, but the same monomer skeleton In this case, Rth tends to be smaller as the weight average molecular weight of the polyimide precursor is larger. The use of DAS as the polymer backbone tends to lower Rth. Although the mechanism of the above-mentioned relation between the weight average molecular weight of the polyimide precursor and the Rth of the polyimide film is unknown, it is considered that the orientation and crystallinity of the molecules of the polyimide film are related.

In a specific aspect, Rth is 300 nm or less from the viewpoint of obtaining a low birefringence polyimide film. In particular, when a polyimide film is used as a display material, Rth is preferably 200 nm or less, more preferably 100 nm or less, more preferably 80 nm or less, more preferably 50 nm or less, and particularly preferably 30 nm. If Rth is 300 nm or less, it is easy to capture an image correctly, and in particular, if Rth is 200 nm or less, color reproducibility of the image is good.

In one aspect, the polyimide film has a retardation in the thickness direction (Rth) of 10 μm or less in the thickness direction of 300 nm or less and / or a yellowness (YI) of 10 μm or less in the film thickness of 20 or less. In one embodiment, the polyimide film has a thickness direction retardation (Rth) in terms of a film thickness of 10 μm of 300 nm or less, and a yellowness (YI) in terms of a film thickness of 10 μm of 20 or less.

(Yellowness of polyimide film (YI))
In a specific aspect, when a polyimide film is produced as a cured product of a polyimide precursor (that is, imidized product), the yellowness (YI) at a film thickness of 10 μm of the polyimide film is 20 or less in view of obtaining good optical characteristics. And preferably 18 or less, more preferably 16 or less, further preferably 14 or less, further preferably 13 or less, still more preferably 10 or less, particularly preferably 7 or less. The YI at a film thickness of 10 μm of the polyimide film varies depending on the monomer skeleton of the polyimide precursor, but if the monomer skeleton is the same, the larger the weight average molecular weight of the polyimide precursor, the smaller the YI tends to be.

(Other desirable characteristics of polyimide film)
When a polyimide film is produced on an inorganic supporting substrate such as a glass substrate as a cured product (i.e., imidized product) of a polyimide precursor, the residual stress generated between the polyimide film and the glass substrate at a film thickness of 10 μm is, for example, From the viewpoint of reducing the amount of warpage of a glass substrate with a polyimide, it is preferably 25 MPa or less, more preferably 23 MPa or less, still more preferably 20 MPa or less, still more preferably 18 MPa or less, particularly preferably 16 MPa or less.

Moreover, it is preferable that the tensile elongation in film thickness of 10 micrometers of the said polyimide film is 15% or more. The tensile elongation is more preferably 20% or more, still more preferably 25% or more, still more preferably 30% or more, still more preferably 35% or more, from the viewpoint of mechanical strength of the flexible display. Preferably it is 40% or more. The tensile elongation of the polyimide film varies depending on the monomer skeleton of the polyimide precursor, but if it is the same monomer skeleton, the tensile elongation tends to increase as the weight average molecular weight of the polyimide precursor increases.

The glass transition temperature Tg of the polyimide film is preferably 360 ° C. or higher, more preferably 400 ° C. or higher, from the viewpoint of being able to raise the process temperature when forming an inorganic film such as silicon nitride on polyimide in the CVD step. Preferably, 470 ° C. or higher is more preferable.

The polyimide film preferably has a uniform film thickness. In particular, when a polyimide film is used as a material of a screen of a flexible display or the like, the wavelength of visible light is about 380 nm to about 700 nm, and the film thickness is particularly high from the viewpoint of obtaining good display performance and the display manufacturing process. Uniformity is required. 10 μm or less is preferable, 8 μm or less is preferable, 5 μm or less is preferable, 3 μm or less is preferable, 2 μm or less is preferable, 1 μm or less is particularly preferable, and 500 nm is uniform The following are particularly preferable, and 300 nm or less is particularly preferable. Although the film thickness uniformity is preferably as small as possible, it may be, for example, 50 nm or more or 100 nm or more from the viewpoint of improving the yield of display production. In addition, the said film thickness uniformity means the value of 3 (sigma) calculated from the film thickness of several points which are measured by the method as described in the term of [Example] of this indication, for example.

(Shear rate dependency of resin composition)
The shear rate dependency (TI) (hereinafter, also simply referred to as TI) of the resin composition of the present embodiment is preferably 0.9 or more and 1.1 or less. In the present disclosure, TI is the viscosity ηa at a measurement rotational speed a (rpm) when the viscosity of the resin composition is measured at 23 ° C. with a temperature controlled viscometer (TVE-35H manufactured by Toki Sangyo Co., Ltd.) From (mPa · s) and viscosity η b (mPa · s) at a measured rotational speed b (rpm) (where a * 10 = b), the following formula:
TI = ηa / ηb
Is a value determined according to Details of the measurement conditions will be described in the description in the examples.

Shear rate dependency (TI) is preferably 0.9 or more, or 0.95 or more, or 1.0 or more, preferably 1.1 or less, or 1.05 or less, or 1.0 or less It is. When the TI is in this range, the resin composition is referred to as a Newtonian fluid, which is preferable because the film thickness uniformity when slit-coating the resin composition is good. A polyimide film obtained by curing a resin composition having a good film thickness uniformity has a good film thickness uniformity, and thus can be suitably used as a material of a screen of a flexible display or the like.

The detailed reason why the film thickness uniformity becomes good when the shear rate dependency of the resin composition is 0.9 or more and 1.1 or less is unclear, but it is considered as follows.
In the slit coat, the shear rate given to the resin composition immediately after the start of application is small, and the shear rate given to the resin composition when the application is continued is large. When the shear rate dependency is small (specifically, TI is 0.9 or more and 1.1 or less), the difference between the viscosity of the resin composition immediately after the start of the application and the time when the application is continued is small. (Machine direction) film thickness variation is small (ie film thickness uniformity in the coating direction is good). When the slit coat nozzle is of a specification in which the resin composition is injected from only one end in the width direction (TD (Transverse direction)), the shear rate of the resin composition is large near the injection port at the time of slit coat. The shear rate of the resin composition decreases on the side opposite to the inlet (i.e., the deadlock side of the nozzle). Even in such a case, the film thickness variation in the width direction can be reduced by the small shear rate dependency (specifically, TI of 0.9 or more and 1.1 or less). Thus, the small shear rate dependency (specifically, TI of 0.9 or more and 1.1 or less) reduces the influence of shear on viscosity, and the variation in film thickness is small in both MD and TD. It offers the advantage of (i.e., good film thickness uniformity).

The shear rate dependency of the resin composition is considered to be correlated with the method of synthesizing the resin composition.
For example, in the reaction vessel, all of acid dianhydride, diamine, and silicone oil which may be acid dianhydride or diamine depending on the structure are added and heated to react, and the diamine is dissolved in a solvent The acid dianhydride and the silicone oil dissolved in a solvent are dropped little by little at room temperature over time, and compared with the case where they are reacted little by little, in the former case, the monomer (ie, acid dianhydride) Among the diamines and silicone oils), those having higher reactivity (such as those having high acidity or basicity, those having less steric hindrance, etc.) react, and the polyimide precursor tends to be a block polymer. On the other hand, in the latter case, acid dianhydride and silicone oil are dissolved in a solvent and added dropwise little by little, so that each monomer can react regardless of the reactivity etc., and the polyimide precursor tends to be a random polymer. is there. Thus, the polymer composition of the product is considered to be different between the former and the latter. And, in the case of block polymer (the former), specific monomers are gathered in the polymer, so intermolecular interaction is likely to occur between polymer chains, and the flexibility of the polymer is impaired. It is considered to be easier. As a result, it is considered that the shear rate dependency of the resin composition is increased. On the other hand, in the case of the latter, since each monomer is bound in order and intermolecular interaction and the like are hard to occur, it is considered that the shear rate dependency is small.

In the former case, since all the monomers are added and heated, it is believed that particularly the acid dianhydride thermally opens the acid dianhydride group before reacting with the polymer chain. When the acid dianhydride group is ring-opened to form a dicarboxylic group, the reactivity is lowered as compared with the acid dianhydride group, and therefore, it is considered that the molecular weight of the polyimide precursor becomes smaller. On the other hand, in the latter case, since the acid dianhydride is dissolved in a solvent and dropped little by little at room temperature, the acid dianhydride group can be reacted with the polymer chain without ring opening. It is believed that the molecular weight increases.

(Slit coat characteristics of resin composition)
The coat characteristic (slit coat characteristic) by the slit nozzle of the resin composition containing a polyimide precursor has correlation with the weight average molecular weight of a polyimide precursor, and solid content of a resin composition. When the polyimide precursor has a low molecular weight and / or the resin composition has a low solid content, liquid leakage from the nozzle is likely to occur, while when the polyimide precursor has a high molecular weight, And / or when the resin composition has a high solid content, clogging of the varnish tends to occur at the nozzle tip. Therefore, it is preferable to control the weight average molecular weight of the polyimide precursor in such a range that the desired slit coat characteristics can be obtained by controlling the solid content.

(Edge characteristics of coating film)
When slit-coating a resin composition containing a polyimide precursor to form a dried coating, an edge is observed if the polyimide precursor has a low molecular weight and / or if the resin composition has a low solid content Edging tends to occur, while edge beads (i.e., edge build-up) tend to occur if the polyimide precursor has a high molecular weight and / or if the resin composition has a high solid content. . Therefore, it is preferable to control the weight average molecular weight of the polyimide precursor in such a range that the desired edge characteristics can be obtained by controlling the solid content.

In one embodiment, the solid content of the resin composition is 10% by mass to 25% by mass. The settable coat gap (i.e., the gap between the tip of the slit coat nozzle and the substrate) at the time of slit coating the resin composition correlates with the solid content of the resin composition, and the solid content contained in the resin composition If the type is the same, the smaller the solid content of the resin composition, the larger the coat gap tends to be. From the viewpoint of good coating, the coat gap is preferably large. For example, when the coat gap is 50 μm or more, the collision between the slit nozzle and the substrate can be avoided even when the substrate size is relatively large. When the solid content of the resin composition is 10% by mass to 25% by mass, the intended coating gap can be realized by selecting the type and molecular weight of the polyimide precursor. The preferred solids content of the resin composition may vary depending on the desired application, the type and molecular weight of the polyimide precursor, the type of solvent that the resin composition may comprise, and the like.

Preferred examples of the lower limit of the solid content are 11 mass%, 12 mass%, 13 mass%, 14 mass%, 15 mass%, 16 mass%, 17 mass%, 18 mass%, 19 mass%, 20 mass% , 21% by mass, 22% by mass, 23% by mass or 24% by mass.

Preferred examples of the upper limit of the solid content are 24 mass%, 23 mass%, 22 mass%, 21 mass%, 20 mass%, 19 mass%, 18 mass%, 17 mass%, 16 mass%, 15 mass% , 14% by mass, 13% by mass, 12% by mass or 11% by mass.

In a preferred embodiment, the solid concentration is 10 to 20% by mass, and more preferably 10 to 15% by mass.

In a preferred embodiment, the polyimide precursor has the formula (3):

[Wherein, each of R ₃ and R ₄ independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a monovalent aromatic group having 6 to 10 carbon atoms, when there are a plurality of each. , And m is an integer of 1 to 200. } Has a structure represented by
The fact that R ₃ and R _{4 each} is a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms or a monovalent aromatic group having 6 to 10 carbon atoms is due to the residual stress and Rth generated with the support. It is advantageous from the viewpoint of obtaining a polyimide that can reduce the The preferred structure of R ₃ and R _4, a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, and the like.
m is 1 to 200, preferably 1 or more, or 3 or more, or 5 or more, preferably 200 or less, from the viewpoint of obtaining a polyimide capable of reducing the residual stress and Rth generated with the support. Or 180 or less, or 160 or less.

The polyimide precursor may have the structure of the formula (3) at any site in the molecule, but the structure of the formula (3) is preferably derived from the diamine component from the viewpoint of the type of siloxane monomer and cost. . The ratio of the structural portion represented by the formula (3) to the total mass of the polyimide precursor is preferably 5% by mass or more, more preferably from the viewpoint of reducing the residual stress and Rth generated with the support. It is 6% by mass or more, more preferably 7% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less from the viewpoint of transparency of the cured product (for example, polyimide film) and heat resistance. More preferably, it is 25 mass% or less.

In a typical aspect, the polyimide precursor of the structure represented by the said Formula (1) is a polymer of the diamine component containing R ₁ group, and the acid dianhydride component containing R ₂ group.

As the acid dianhydride containing an R ₂ group, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic acid Acid dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride, 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-cyclohexene-1,2 dicarboxylic anhydride 1,2,3,4-Benzenetetracarboxylic acid dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid dianhydride, 2,2 ′, 3,3′-benzophenonetetracarboxylic acid Anhydride, 3,3 ', 4,4'-Diphenylsulfone tetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-diphthalic dianhydride , 2,2-Proprylidene-4 4'-diphthalic 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, p-phenylene bis (trimellitic acid anhydride) , 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 dianhydride, 1,2,5,6-naphthalene ether Lacarboxylic acid dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride, 2,3,6,7-anthracenetetracarboxylic acid dianhydride, 1,2,7,8-phenanthrene tetracarboxylic acid A dianhydride etc. can be illustrated.

Among them, pyromellitic dianhydride (PMDA) and biphenyl tetracarboxylic dianhydride (BPDA) are used when the solid content of the resin composition is controlled within the predetermined weight average molecular weight of the polyimide precursor. It is preferable from the viewpoint that good slit coat performance and good mechanical properties, optical properties and high glass transition temperature of a cured product (for example, a polyimide film) can be easily obtained. In one aspect, the polyimide precursor having a structure represented by Formula (1) is a copolymer of tetracarboxylic acid dianhydride and diamine. In one aspect, the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride with pyromellitic dianhydride (PMDA) and a diamine. In one embodiment, the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride containing 3,3 ', 4,4'-biphenyl tetracarboxylic acid dianhydride and a diamine.

In a particular embodiment, the total content of pyromellitic dianhydride (PMDA) and biphenyltetracarboxylic acid dianhydride (BPDA) in total acid dianhydrides has good slit coat performance and cured products ( For example, in view of obtaining good thickness direction retardation (Rth), yellowness (YI), glass transition temperature Tg and elongation of a polyimide film), it is preferably 60 mol% or more, more preferably 80 mol% or more, particularly preferably Is 100 mol%.

In a particular embodiment, the content of pyromellitic dianhydride (PMDA) in total acid dianhydride has good slit coat performance, as well as good glass transition temperature Tg of the cured product (eg polyimide film) From the viewpoint of obtaining, 0 mol% or more is preferable, 10 mol% or more is preferable, 20 mol% or more is preferable, 100 mol% or less is preferable, and 90 mol% or less is preferable.

In a particular embodiment, the content of biphenyltetracarboxylic acid dianhydride (BPDA) in the total acid dianhydride has good slit coat performance as well as good thickness direction retardation of the cured product (eg polyimide film) From the viewpoint of obtaining (Rth), yellowness (YI) and elongation, 0 mol% or more is preferable, 10 mol% or more is preferable, 20 mol% or more is preferable, 100 mol% or less is preferable, 90 mol% or less Is preferred.

In a particular embodiment, the content ratio of pyromellitic dianhydride (PMDA): biphenyltetracarboxylic dianhydride (BPDA) in the acid dianhydride is a good thickness direction retardation of a cured product (eg polyimide film) From the viewpoint of achieving both (Rth), yellowness (YI) and heat resistance represented by glass transition temperature, 20:80 to 80:20 is preferable, and 30:70 to 70:30 is more preferable. In a particular embodiment, the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride and a diamine, said tetracarboxylic acid dianhydride being pyromellitic dianhydride and 3,3 ', 4,4. The molar ratio of pyromellitic dianhydride to 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride is preferably 20:80 to 80:20, more preferably 30. : 70 to 70:30 inclusive.

Examples of the diamine containing an R ₁ group in the formula (1) include diaminodiphenyl sulfone (eg, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone), p-phenylenediamine, m-phenylenediamine, 4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4 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-aminophenoxy) 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-amino) Phenoxy) phenyl) hexafluoropropane, 1,4-bis (3-aminopropyl dimethylsilyl) benzene, and the like.

A diamine used to form a polyimide precursor having a structure represented by the formula (1) is diaminodiphenyl sulfone (eg, 4,4′-diaminodiphenyl sulfone and / or 3,3′-diaminodiphenyl sulfone) It is preferable to include.

The content of diaminodiphenyl sulfone in all diamines is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and may be 95 mol% or more. The larger the amount of diaminodiphenyl sulfone, the more preferable in view of the yellowness (YI) of the cured product (for example, polyimide film), the glass transition temperature Tg, and the retardation Rth in the thickness direction. As the diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone is particularly preferable from the viewpoint of low yellowness (YI).

In a preferred embodiment, the diamine to be copolymerized with diaminodiphenyl sulfone is preferably diamidobiphenyls, more preferably diaminobis (triol) from the viewpoint of heat resistance of the cured product (eg polyimide film) and yellowness (YI). Fluoromethyl) biphenyl (TFMB) is included. The content of diaminobis (trifluoromethyl) biphenyl (TFMB) in all diamines is preferably 20 mol% or more, more preferably 30 mol% or more from the viewpoint of the degree of yellowness (YI) of the cured product (for example, polyimide film) From the viewpoint of enabling the diamine to contain other advantageous components such as diaminodiphenyl sulfone, it is preferably at most 80 mol%, more preferably at most 70 mol%.

In a preferred embodiment, the diamine comprises a silicon containing diamine. In a more preferred embodiment, the diamine comprises a silicon-containing diamine comprising a structure represented by Formula (3) above. As the silicon-containing diamine, for example, the following formula (3a):

{Wherein R ₅ represents a divalent hydrocarbon group, which may be the same or different, and each of a plurality of R ₃ and R ₄ is the same as defined in the formula (3), and l represents an integer of 1 to 200. The diamino (poly) siloxane represented by} can be used suitably.

The preferred structure of R ₅ in the general formula (3a), a methylene group, an ethylene group, a propylene group, a butylene group, a phenylene group, and the like. Moreover, as a preferable structure of R < ₃ > and R < ₄ > in Formula (3a), a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group etc. are mentioned.

The number average molecular weight of the compound represented by the above formula (3a) is preferably 500 or more, more preferably from the viewpoint of reduction of residual stress generated between a cured product (for example, a polyimide film) to be obtained and a support. Is preferably 1,000 or more, more preferably 2,000 or more, and preferably 12,000 or less, more preferably 10,000, from the viewpoint of the transparency (particularly low haze) of the resulting cured product (eg, polyimide film). The following is more preferably 8,000 or less.

Specific examples of the compound represented by the above formula (3a) include both terminal amine-modified methylphenylsilicone oil (manufactured by Shin-Etsu Chemical Co., Ltd .: X22-1660B-3 (number average molecular weight 4400), X22-9409 (number average) Molecular weight 1300)) Both terminal amino modified dimethyl silicone (Shin-Etsu Chemical Co., Ltd .: X22-161A (number average molecular weight 1600), X22-161B (number average molecular weight 3000), KF 8012 (number average molecular weight 4400), Toray Dow Corning: BY16-835U (number average molecular weight 900) manufactured by Chisso Corporation: Silaprene FM 3311 (number average molecular weight 1000) and the like. Among these, a both-end amine modified methylphenyl silicone oil is preferable from the viewpoint of chemical resistance improvement and Tg improvement.

The copolymerization ratio of the silicon-containing diamine is preferably in the range of 0.5 to 30% by mass, more preferably 1.0% to 25% by mass, still more preferably 1.5% by mass with respect to the mass of all the polyimide precursors. It is mass% to 20 mass%. When the content is 0.5% by mass or more, the effect of reducing the stress generated with the support is good. When the content is 30% by mass or less, the transparency (particularly low haze) of the cured product (for example, a polyimide film) obtained is good, which is preferable in terms of realization of high total light transmittance and prevention of lowering of Tg.

As an acid component for forming a polyimide precursor in this embodiment, in addition to an acid dianhydride (for example, the tetracarboxylic acid dianhydride exemplified above), a dicarboxylic acid can be added within a range that does not impair its performance. You may use it. That is, the polyimide precursor of the present disclosure may be a polyamideimide precursor. A film obtained from such a polyimide precursor can have good properties such as mechanical elongation, glass transition temperature Tg, yellowness (YI) and the like. Examples of the dicarboxylic acid to be used include dicarboxylic acids having an aromatic ring and alicyclic dicarboxylic acids. Particularly preferred is 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. 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 -Naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-sulfonylbisbenzoic acid, 3,4'-sulfonylbisbenzoic acid, 3,3'-sulfonylbisbenzoic acid 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'-biphenyldicarboxylic acid, 3,3'-dimethyl-4,4'-biphenyl dical Acid, 2,2'-dimethyl-3,3'-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) biphenyl, 3,3'-bis (4-carboxyphenoxy) biphenyl, 3,3'-bis (3-carboxyphenoxy) biphenyl, 4,4'-bis (4-carboxyphenoxy) ) -P-terphenyl, 4,4'-bis (4-carboxyphenoxy) -m-terphenyl, 3,4'-bis (4-) Ruboxyphenoxy) -p-terphenyl, 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'-benzophenonedicarboxylic acid, 1,3-phenylenediacetic acid, 1,4-phenylenediacetic acid, etc .; and 5-amino described in WO 2005/068535. Isophthalic acid derivatives and the like 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.

In a preferred embodiment, the polyimide precursor comprises tetracarboxylic acid dianhydride, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 2,2'-bis (trifluoromethyl) benzidine and 9 , 9-bis (4-aminophenyl) fluorene and copolymers with one or more diamines selected from the group consisting of

As a particularly preferred polyimide precursor, the following may be mentioned.
(1) Polycondensate of material components in which the acid dianhydride component is pyromellitic dianhydride (PMDA) and biphenyltetracarboxylic acid dianhydride (BPDA), and the diamine component is diaminodiphenyl sulfone (DAS) (more preferable Is a weight average molecular weight of 110,000 to 130,000, solid content 12 to 25 mass%)
(2) Polycondensation of material components in which the acid dianhydride component is pyromellitic dianhydride (PMDA) and biphenyltetracarboxylic dianhydride (BPDA), and the diamine component is diaminodiphenyl sulfone (DAS) and a silicon-containing diamine (More preferably, weight average molecular weight 110,000 to 210,000, solid content 10 to 25 mass%)
(3) The acid dianhydride component is pyromellitic dianhydride (PMDA) and biphenyltetracarboxylic acid dianhydride (BPDA), and the diamine component is diaminodiphenylsulfone (DAS), diaminobis (trifluoromethyl) biphenyl (TFMB) And polycondensates of material components that are silicon-containing diamines (more preferably, weight average molecular weight 110,000 to 250,000, solid content 10 to 25 mass%)

(4) Polycondensate of material components wherein the acid dianhydride component is pyromellitic dianhydride (PMDA) and the diamine component is diaminodiphenyl sulfone (DAS) (more preferably, weight average molecular weight 110,000 to 140, 000, solid content 10 to 25 mass%)
(5) Polycondensate of material components wherein the acid dianhydride component is pyromellitic dianhydride (PMDA), the diamine component is diaminodiphenyl sulfone (DAS) and a silicon-containing diamine (more preferably, weight average molecular weight 110, 000 to 230,000, solid content 10 to 25% by mass)
(6) Polycondensation of material components in which the acid dianhydride component is pyromellitic dianhydride (PMDA) and the diamine component is diaminodiphenyl sulfone (DAS), diaminobis (trifluoromethyl) biphenyl (TFMB) and silicon-containing diamine (More preferably, weight average molecular weight 110,000 to 250,000, solid content 10 to 25 mass%)

(7) Polycondensate of material components wherein the acid dianhydride component is biphenyltetracarboxylic acid dianhydride (BPDA) and the diamine component is diaminodiphenyl sulfone (DAS) (more preferably, weight average molecular weight 110,000 to 120) , Solid content 20 to 25 mass%)
(8) A polycondensate of material components in which the acid dianhydride component is biphenyltetracarboxylic acid dianhydride (BPDA) and the diamine component is diaminodiphenylsulfone (DAS) and a silicon-containing diamine (more preferably, weight average molecular weight 110) 1,000 to 160,000, solid content 10 to 25% by mass)
(9) The weight of the material component in which the acid dianhydride component is biphenyltetracarboxylic acid dianhydride (BPDA), and the diamine component is diaminodiphenylsulfone (DAS), diaminobis (trifluoromethyl) biphenyl (TFMB) and a silicon-containing diamine Condensate (more preferably, weight average molecular weight 110,000 to 240,000, solid content 10 to 25% by mass)

In the material component of the polycondensate of the above (1) to (9), the silicon-containing diamine is preferably a diamino (poly) siloxane represented by the above-mentioned formula (3a) (preferably a number average molecular weight of 500 to 12,000). And, more preferably, both terminal amine-modified methylphenylsilicone oils.

[Production of Polyimide Precursor]
The polyimide precursor of the present embodiment can be synthesized by subjecting a polycondensation component including an acid dianhydride component and a diamine component to a polycondensation reaction. In a preferred embodiment, the polycondensation component comprises an acid dianhydride component and a diamine component. The polycondensation reaction is preferably carried out in a suitable solvent. Specifically, for example, there is a method of dissolving a predetermined amount of diamine component in a solvent, adding a predetermined amount of acid dianhydride to the obtained diamine solution, and stirring.

The molar ratio between the acid dianhydride component and the diamine component when synthesizing the polyimide precursor is from the viewpoint of the polymerization of the polyimide precursor resin and the slit coating characteristics of the resin composition, acid dianhydride: diamine = 100 It is preferable to make the range of 90: 100: 110 (the diamine 0.90 to 1.10 mole parts with respect to 1 mole part of the acid dianhydride), and 100: 95 to 100: 105 (one mole of the acid dianhydride) It is further preferable to set the range of 0.95 to 1.05 mole parts of diamine) with respect to part.

The molecular weight of the polyimide precursor can be controlled by adjusting the type of acid dianhydride component and diamine component, adjusting the ratio of acid dianhydride component and diamine component, adding an end capping agent, adjusting the reaction conditions, etc. It is. The polyimide precursor can be made higher in molecular weight 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 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. Moreover, it can also be highly purified by reducing the water content in an acid dianhydride component and a diamine component. 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.

The solvent for the reaction is not particularly limited as long as it can dissolve the acid dianhydride component and the diamine component, and the resulting polyimide precursor, and a polymer of high molecular weight can be obtained. Examples of such solvents include, for example, aprotic solvents, phenolic solvents, ethers and glycol solvents. Specific examples thereof include, as the aprotic solvent, for example, N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N-methyl Caprolactam, 1,3-dimethylimidazolidinone, tetramethyl urea, the following general formula (4):

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 dimethylsulfone, dimethylsulfoxide and sulfolane Solvents: Ketone solvents such as cyclohexanone and methylcyclohexanone; Tertiary amine solvents such as picoline and pyridine; Ester solvents such as acetic acid (2-methoxy-1-methylethyl) and the like: As the phenol solvents, For example, phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2, —Xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol etc. as said ether and glycol solvents, for example, 1,2-dimethoxyethane, bis (2- Examples thereof include methoxyethyl) ether, 1,2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethyl] ether, tetrahydrofuran, 1,4-dioxane and the like. These solvents may be used alone or in combination of two or more.

The boiling point at normal pressure of the solvent used for the synthesis of the polyimide precursor is preferably 60 to 300 ° C., more preferably 140 to 280 ° C., and particularly preferably 170 to 270 ° C. 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., the surface of the resin film may be roughened, air bubbles may be mixed into the resin film, and the like during the drying process, and a uniform film may not be obtained. In particular, it is preferable to use a solvent having a boiling point of 170 to 270 ° C. and / or a vapor pressure of 250 Pa or less at 20 ° C. in view of solubility and edge repelling during coating. More specifically, one or more selected from the group consisting of N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), and a compound represented by the above general formula (4) is preferable.

The water content in the solvent is preferably, for example, 3,000 ppm by mass or less from the viewpoint of the progress of a good polycondensation reaction. Moreover, in the resin composition in the present embodiment, the content of molecules having a molecular weight of less than 1,000 is preferably less than 5% by mass. The presence of molecules having a molecular weight of less than 1,000 in the resin composition is considered to be due to the water content of the solvent used during synthesis and the raw materials (acid dianhydride, diamine). 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 smaller the water content of the solvent used for the polycondensation reaction, the better. 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. Similarly, the amount of water contained in the raw material is also 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, when synthesizing the polyimide precursor, it is recommended to use a high purity product as a raw material and use a solvent with a small amount of water, and to take measures so that water from the environment does not enter the system before and during the reaction. Be done.

When dissolving each polycondensation component in a solvent, it may be heated if necessary. From the viewpoint of obtaining a polyimide precursor having a high degree of polymerization, preferred reaction temperatures at the time of polyimide precursor synthesis include 0 ° C. to 120 ° C., 40 ° C. to 100 ° C., or 60 to 100 ° C. The time may be, for example, 1 to 100 hours, or 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.

The resin composition of the present embodiment may be a combination of a polyimide precursor having a structure represented by Formula (1) and another additional polyimide precursor, but the mass ratio of the additional polyimide precursor Is 30% by mass or less based on the total amount of the polyimide precursor in the resin composition from the viewpoint of reducing the degree of yellowness (YI) of the cured product (for example, polyimide film) and the oxygen dependency of the total light transmittance. Is preferable, and 10% by mass or less is more preferable.

In a preferred aspect of the present embodiment, a part of the polyimide precursor may be imidized. The partially imidized polyimide precursor can improve the viscosity stability of the resin composition when stored at room temperature. The imidation ratio in this case is preferably 5% or more, more preferably 8% or more, from the viewpoint of balancing the solubility of the polyimide precursor in the resin composition with the storage stability of the solution, and is preferably Is 80% or less, more preferably 70% or less, and still more preferably 50% or less. This partial imidization is obtained by heating and dehydrating the ring closure of the polyimide precursor. This heating can be carried out preferably at a temperature of 120 to 200 ° C., more preferably 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 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.

In one aspect, the resin composition comprises a solvent. As the solvent, one having good solubility of the polyimide precursor and capable of appropriately controlling the solution viscosity of the resin composition is preferable, and the reaction solvent of the polyimide precursor can be used as a solvent of the composition. Among them, N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), a compound represented by the above general formula (4), and the like are preferable. Specific examples of the solvent composition include N-methyl-2-pyrrolidone (NMP) alone or a mixed solvent of N-methyl-2-pyrrolidone (NMP) and γ-butyrolactone (GBL) (for example, NMP: GBL (mass) Ratio) = 10: 90 to 90:10) and the like.

[Additional ingredient]
The resin composition of the present embodiment may contain additional components in addition to (a) a polyimide precursor and (b) a solvent. Examples of additional components include (c) surfactants, (d) alkoxysilane compounds, and the like.

((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 include silicone surfactants such as organosiloxane polymers KF-640, 642, 643, KP 341, X-70-092, X-70-093 (all trade names, Shin-Etsu Chemical Co., Ltd.) ), SH-28PA, 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 (all trade names, manufactured by Nippon Unicar Co., Ltd.), DBE-814, DBE-224, DBE- 621, CMS-626, CMS-222, KF-352A, KF-354L, KF-355A, KF-6020, DB E-821, DBE-712 (Gelest), BYK-307, BYK-310, BYK-378, BYK-333 (all trade names, manufactured by BIC Chemie Japan), Granol (trade names, manufactured by Kyoeisha Chemical Co., Ltd.), etc. As fluorinated surfactants, for example, Megafac F171, F173, R-08 (Dainippon Ink and Chemicals, Inc., trade name), Florard FC4430, FC4432 (Sumitomo 3M Ltd., trade name), etc .; As a nonionic surfactant other than, for example, polyoxyethylene uralyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether and the like can be mentioned, respectively.

Among these surfactants, silicone surfactants and fluorosurfactants are preferable from the viewpoint of the coating property (stripping suppression) of the resin composition, and the yellowness (YI) value due to the oxygen concentration at the curing step is preferable. In view of the influence on the total light transmittance and the silicone resin, silicone surfactants are preferred. When a surfactant (c) is used, the amount thereof is preferably 0.001 to 5 parts by mass, and 0.01 to 3 parts by mass with respect to 100 parts by mass of (a) polyimide precursor in the resin composition. Is more preferred.

(D) Alkoxysilane Compound When the polyimide film obtained from the resin composition according to the present embodiment is used for a flexible substrate or the like, the resin composition from the viewpoint of obtaining good adhesion between the support and the polyimide film in the manufacturing process. The substance may contain 0.01 to 20 parts by mass of the alkoxysilane compound with respect to 100 parts by mass of the (a) polyimide precursor. When the content of the alkoxysilane compound is 0.01 parts by mass or more based on 100 parts by mass of the polyimide precursor, good adhesion can be obtained between the support and the polyimide film. Moreover, it is preferable from a viewpoint of the storage stability of a resin composition that content of an alkoxysilane compound is 20 mass parts or less. The content of the alkoxysilane compound is more preferably 0.02 to 15 parts by mass, still more preferably 0.05 to 10 parts by mass, with respect to 100 parts by mass of the polyimide precursor. Particularly preferred is 8 parts by mass.
Further, by using an alkoxysilane compound as an additive of the resin composition according to the present embodiment, in addition to the improvement of the above-mentioned adhesion, the improvement of the coating property (suppression of uneven streaks) of the resin composition, and It is also possible to reduce the oxygen concentration dependence during curing of the yellowness (YI) value of the cured film.

Examples of the alkoxysilane compound include 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, diphenylsilane And dimethoxydiphenylsilane, diethoxydiphenylsilane, dimethoxydi-p-tolylsilane, triphenylsilanol and alkoxysilane compounds represented by the following structures, respectively, and one or more selected from these can be used. It is preferable to do.

The manufacturing method of the resin composition in this Embodiment is not specifically limited, For example, it can be based on the following method.

When the solvent used when synthesizing (a) the polyimide precursor and the solvent to be contained in (b) the resin composition are the same, the synthesized polyimide precursor solution can be used as it is as the resin composition. . Also, if necessary, one or more of (b) a solvent and one or more additional components are added to (a) a polyimide precursor in a temperature range of room temperature (25 ° C.) to 80 ° C. and stirred and mixed. And may be used as a resin composition. 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. Further, heat of 40 to 100 ° C. may be added if necessary.

On the other hand, when the solvent used when synthesizing the (a) polyimide precursor and the solvent to be contained in the (b) resin composition are different, the solvent in the synthesized polyimide precursor solution is, for example, reprecipitated, After removing by a suitable method such as evaporation of solvent and isolating (a) the polyimide precursor, (b) a solvent and, if necessary, additional components are added in a temperature range of room temperature to 80 ° C. The resin composition may be prepared by stirring and mixing.

After preparing the resin composition as described above, the composition is heated, for example, at 130 to 200 ° C., for example, for 5 minutes to 2 hours to dehydrate a portion of the polyimide precursor to such an extent that the polymer does not precipitate. May be Here, the imidization rate can be controlled by controlling the heating temperature and the heating time. As described above, the partially imidized polyimide precursor can improve the viscosity stability of the resin composition when stored at room temperature.

From the viewpoint of slit coat performance, the solution viscosity of the resin composition is preferably 500 to 100,000 mPa · s, more preferably 1,000 to 50,000 mPa · s, and particularly preferably 3,000 to 20,000 mPa · s. preferable. Specifically, the viscosity is preferably 500 mPa · s or more, more preferably 1,000 mPa · s or more, and still more preferably 3,000 mPa · s or more, in terms of preventing liquid leakage from the slit nozzle. Further, it is preferably 100,000 mPa · s or less, more preferably 50,000 mPa · s or less, and still more preferably 20,000 mPa · s or less, from the viewpoint that the slit nozzle is not easily clogged. In addition, from the viewpoint of viscosity at the time of synthesis, when the solution viscosity of the resin composition is higher than 200,000 mPa · s, there may be a problem that stirring at the time of synthesis becomes difficult. However, even when the solution has a high viscosity at the time of synthesis, it is possible to obtain a resin composition having a manageable viscosity by adding a solvent and stirring after completion of the reaction. The solution viscosity of the resin composition in the present disclosure is a value measured at 23 ° C. using an E-type viscometer (for example, VISCONICEHD, manufactured by Toki Sangyo Co., Ltd.).

The water content of the resin composition according to the present embodiment is preferably 3,000 ppm by mass or less. The water content of the resin composition is preferably 2,500 mass ppm or less, preferably 2,000 mass ppm or less, and preferably 1,500 mass ppm or less from the viewpoint of viscosity stability when storing the resin composition. The amount is preferably 1,000 ppm by mass or less, more preferably 500 ppm by mass or less, preferably 300 ppm by mass or less, and preferably 100 ppm by mass or less.

<Method for producing polyimide film>
In the present embodiment,
Applying the resin composition of the present embodiment on the surface of the support;
A film forming step of heating the resin composition to form a polyimide film;
And R. a peeling step of peeling the polyimide film from the support.

[Coating process]
In the coating step, the resin composition is coated on the surface of the support. The support is not particularly limited as long as it has heat resistance at the heating temperature of the subsequent film forming step (heating step), and further, if the peelability in the peeling step is good. For example, glass (for example, alkali-free glass) substrate; silicon wafer; PET (polyethylene terephthalate), OPP (oriented polypropylene), polyethylene glycol terephthalate, polyethylene glycol naphthalate, polycarbonate, polyimide, polyamide imide, polyether imide, polyether ether Resin substrates such as ketone, polyether sulfone, polyphenylene sulfone and polyphenylene sulfide; metal substrates such as stainless steel, alumina, copper, nickel and the like are used.

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

Coating methods generally include doctor blade knife coater, air knife coater, roll coater, rotary coater, flow coater, die coater, bar coater and other coating methods, spin coating, spray coating, dip coating and other coating methods; screen printing And printing techniques represented by gravure printing etc., and the resin composition of the present embodiment is particularly useful for slit coating (that is, coating with a slit coater). The coating thickness should be appropriately adjusted in accordance with the desired thickness of the polyimide film and the content of the polyimide precursor in the resin composition, and is preferably about 1 to 1,000 μm. Although the application step is sufficient at room temperature, the resin composition may be heated, for example, in the range of 40 to 80 ° C. for the purpose of lowering the viscosity to improve the workability.

[Optional drying process]
Subsequent to 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 film forming step (heating step). The drying step is performed for the purpose of removing the organic solvent in the resin composition. 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 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.

[Film formation process]
Subsequently, a film forming step (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 polyimide film. 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 in an air atmosphere, but from the viewpoint of safety, good transparency of the obtained polyimide film, low thickness direction retardation (Rth) and low yellowness (YI), inert gas It is recommended to do under the atmosphere. Examples of the inert gas include nitrogen, argon and the like. The heating temperature may be appropriately set depending on the type of polyimide precursor and the type of solvent in the resin composition, but is preferably 250 ° C. to 550 ° C., and more preferably 300 to 450 ° C. If the temperature is 250 ° C. or higher, the imidization proceeds well, and if the temperature is 550 ° C. or lower, disadvantages such as a decrease in transparency of the obtained polyimide film and a deterioration in heat resistance can be avoided. The heating time is preferably about 0.1 to 10 hours.

In the present embodiment, the oxygen concentration in the ambient atmosphere in the above heating step is preferably 2,000 ppm by mass or less, and 100 mass ppm or less from the viewpoint of the transparency and yellowness (YI) value of the polyimide film obtained. More preferably, 10 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 yellowness (YI) value of the obtained polyimide film can be made to be 30 or less.

[Peeling process]
Next, in the peeling step, the polyimide film on the support is peeled, for example, after cooling to about room temperature to about 50 ° C. Examples of this peeling step include the following embodiments (1) to (4).

(1) A polyimide film / substrate comprising a polyimide film / support is produced by the above method, and then the laser is irradiated from the substrate side of the structure to ablate the interface between the substrate and the polyimide film. How to peel off the 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 coating the resin composition on the support, thereafter obtaining a structure including a polyimide film / release layer / support, and releasing the polyimide film. Examples of the peeling layer include a method using Parylene (registered trademark, manufactured by Japan Parylene Joint Company) and tungsten oxide; a method using a releasing agent such as vegetable oil type, silicone type, fluorine type and alkyd type (JP-A-2010) -67957, JP-A-2013-179306 etc.).
This method (2) may be used in combination with the laser irradiation of the above (1).

(3) A method of obtaining a polyimide film by etching a metal with an etchant after obtaining a structure including a polyimide 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 composition including a polyimide film / support by the above method, an adhesive film is attached to the surface of the polyimide film, the adhesive film / polyimide film is separated from the support, and then the polyimide film is removed from the adhesive film How to separate.

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 obtained polyimide film, the yellowness (YI) value, and the elongation, From the viewpoint of the difference in refractive index between the front and back, it is more appropriate to carry out method (1), that is, an irradiation step of irradiating the laser from the support side prior to the peeling step.
In addition, in the method (3), when copper is used as a support body, the yellowness (YI) value of the polyimide film obtained becomes large, and the tendency for elongation to become small is seen. This is considered to be the effect of copper ions.

The thickness of the polyimide film obtained by the above method is not particularly limited, but is preferably in the range of 1 to 200 μm, more preferably 5 to 100 μm.

<Use of polyimide film>
The polyimide film obtained from the polyimide precursor according to the present embodiment can be applied as, for example, a semiconductor insulating film, a TFT-LCD insulating film, an electrode protective film, etc. In addition, in the manufacture of flexible devices, particularly a TFT substrate or a color filter substrate And can be suitably used as a touch panel substrate. Here, as a flexible device to which the polyimide film according to the present embodiment can be applied, for example, a TFT device for a flexible display, a flexible solar cell, a flexible touch panel, a flexible illumination, a flexible battery, a flexible printed circuit, a flexible color filter, a smartphone Facing surface cover lens etc. can be mentioned.

The process of forming a TFT on a flexible substrate using a polyimide film is typically performed at a wide range of temperatures from 150 to 650.degree. Specifically, when manufacturing a TFT device using amorphous silicon, a process temperature of 250 ° C. to 350 ° C. is generally required, and the polyimide film of this embodiment needs to be able to withstand that temperature. Specifically, it is necessary to appropriately select a polymer structure having a glass transition temperature higher than the process temperature and a thermal decomposition start temperature.

When manufacturing a TFT device using a metal oxide semiconductor (such as IGZO), a process temperature of 320 ° C. to 400 ° C. is generally required, and the polyimide film of this embodiment needs to be able to withstand that temperature. Therefore, it is necessary to appropriately select a polymer structure having a glass transition temperature higher than the TFT manufacturing process maximum temperature and a thermal decomposition start temperature.

When manufacturing a TFT device using low temperature polysilicon (LTPS), a process temperature of 380 ° C. to 520 ° C. is generally required, and the polyimide film of the present embodiment needs to be able to withstand that temperature. It is necessary to appropriately select a glass transition temperature higher than the TFT manufacturing process maximum temperature and a thermal decomposition start temperature.
On the other hand, due to these heat histories, the optical properties of the polyimide film (particularly, light transmittance, retardation properties and yellowness) tend to decrease as they are exposed to high temperature processes. However, the polyimide obtained from the polyimide precursor of the present embodiment has good optical properties even after thermal history.

Below, a display, a laminated body, and the manufacturing method of these are demonstrated as an application example of the resin composition of this Embodiment, and a polyimide film.

[Display and Method of Manufacturing the Same]
The present embodiment also provides a flexible device including a polyimide film which is a cured product of the resin composition of the present embodiment. A preferred example of the flexible device is a flexible display. In one aspect, the polyimide film is excellent in optical properties (eg, Rth and / or yellowness). Therefore, in a preferred embodiment, the polyimide film is disposed at a location (specifically, the screen portion of the flexible display) to be viewed when the display is observed from the outside.

In the present embodiment,
Applying (preferably slit coating) the resin composition of the present embodiment on the surface of a support such as a glass substrate;
A film forming step of heating the resin composition to form a polyimide film;
An element forming step of forming an element on a polyimide film;
And a peeling step of peeling the polyimide film on which the element is formed from the support.

[Method of manufacturing flexible organic EL display]
FIG. 1 is a view showing a structure of a top emission type flexible organic EL display as an example of a display provided in one embodiment of the present invention above a polyimide substrate. The organic EL structure 25 shown in FIG. 1 is, for example, an organic EL element 250a emitting red light, an organic EL element 250b emitting green light, and an organic EL element 250c emitting blue light, each forming a matrix. The light emitting area of each organic EL element is defined by the barrier rib (bank) 251. Each organic EL element is composed of a lower electrode (anode) 252, a hole transport layer 253, a light emitting layer 254, and an upper electrode (cathode) 255. In addition, on the lower layer 2a showing a CVD multilayer film (multi-barrier layer) made of silicon nitride (SiN) or silicon oxide (SiO), a TFT 256 (low temperature polysilicon (LTPS), A plurality of interlayer insulating films 258 provided with contact holes 257 and lower electrodes 259 are provided, which are selected from metal oxide semiconductors (such as IGZO). The organic EL element is sealed by a sealing substrate 2b, and a hollow portion 261 is formed between each organic EL element and the sealing substrate 2b.

In the flexible organic EL display manufacturing process, a polyimide film is prepared on a glass substrate support, and the process of manufacturing the organic EL substrate shown in FIG. 1 above, the sealing substrate manufacturing process, and assembly of bonding both substrates The process and the peeling process of peeling the organic electroluminescent display produced on the polyimide film from the glass substrate support are included.
A well-known manufacturing process can be applied to the organic EL substrate manufacturing process, the sealing substrate manufacturing process, and the assembling process. Although the example is given below, it is not limited to this. Moreover, the peeling process may be the same as the peeling process of the polyimide film mentioned above.

Referring to FIG. 1, for example, first, the polyimide film of the present disclosure is produced on a glass substrate support by the method described above, and silicon nitride (SiN) and silicon oxide (SiO) are formed thereon by CVD or sputtering. A multi-barrier layer (lower substrate 2a in FIG. 1) having a multi-layered structure is produced, and a metal wiring layer for driving the TFT is produced thereon using a photoresist or the like. An active buffer layer of SiO or the like is formed thereon by the CVD method, and a TFT device (TFT 256 in FIG. 1) such as metal oxide semiconductor (IGZO) or low temperature polysilicon (LTPS) is formed thereon. After manufacturing a flexible display TFT substrate, an interlayer insulating film 258 provided with a contact hole 257 is formed of a photosensitive acrylic resin or the like. An ITO film is formed by sputtering or the like, and the lower electrode 259 is formed to be paired with the TFT.

Next, after a partition (bank) 251 is formed of photosensitive polyimide or the like, a hole transport layer 253 and a light emitting layer 254 are formed in each space partitioned by the partition. Further, the upper electrode (cathode) 255 is formed so as to cover the light emitting layer 254 and the partition (bank) 251. Thereafter, using a fine metal mask or the like as a mask, an organic EL material (corresponding to the organic EL element 250a emitting red light in FIG. 1) emitting red light, an organic EL material emitting green light (FIG. 1) (Corresponding to the organic EL element 250b emitting green light) and the organic EL material emitting blue light (corresponding to the organic EL element 250c emitting blue light in FIG. 1) by a known method Then, after the organic EL substrate is manufactured and sealed with a sealing film or the like (the sealing substrate 2b in FIG. 1), the device above the polyimide substrate is peeled from the glass substrate support by a known peeling method such as laser peeling. As a result, a top emission type flexible organic EL display is manufactured. When the polyimide of the present embodiment is used, a see-through flexible organic EL display is manufactured. Further, a bottom emission type flexible organic EL display may be manufactured by a known method.

[Method of manufacturing flexible liquid crystal display]
A flexible liquid crystal display can be manufactured using the polyimide film of the present embodiment. As a specific preparation method, a polyimide film according to the present invention is prepared on a glass substrate support by the above-mentioned method, and amorphous silicon, metal oxide semiconductor (IGZO etc.), or A TFT substrate made of low temperature polysilicon is manufactured. Separately, according to the coating step and the film forming step of the present embodiment, a polyimide film is prepared on a glass substrate support, and a color filter glass substrate provided with a polyimide film using a color resist or the like according to a known method Create a CF substrate). A sealing material composed of a thermosetting epoxy resin or the like is applied to one of a TFT substrate and a CF substrate by screen printing in a frame-like pattern lacking a liquid crystal injection port, and the other substrate is a liquid crystal layer Spray a spherical spacer of plastic or silica with a diameter corresponding to the thickness.

Then, the TFT substrate and the CF substrate are bonded to each other, and the sealing material is cured.
Finally, a liquid crystal material is injected into the space surrounded by the TFT substrate, the CF substrate, and the seal material by a pressure reduction method, a thermosetting resin is applied to the liquid crystal injection port, and the liquid crystal material is sealed by heating. Form Finally, the flexible liquid crystal display can be manufactured by peeling the glass substrate on the CF side and the glass substrate on the TFT side at the interface between the polyimide film and the glass substrate by a laser peeling method or the like.

[Method of manufacturing laminate]
In the present embodiment,
Applying the resin composition of the present embodiment on the surface of the support;
A film forming step of heating the resin composition to form a polyimide film;
And a device forming step of forming a device on a polyimide film.

As an element in a laminated body, what was illustrated as said flexible device (for example, flexible display) is mentioned. For example, a glass substrate is used as the support. Preferred specific procedures of the coating step and the film forming step are the same as those described above for the method for producing the polyimide film. In the element formation step, the above-described element is formed on a polyimide film as a flexible substrate, which is formed on a support. Thereafter, the polyimide film and the device may optionally be peeled off from the support in the peeling step.

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.

<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, NMP (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 99.5%) just before measurement and 63 A 2 mmol / L phosphoric acid (manufactured by Wako Pure Chemical Industries, Ltd., for high performance liquid chromatograph) was added and dissolved. A calibration curve for calculating 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)

<Shear rate dependency (TI) evaluation>
The viscosity of the resin composition to be measured using the temperature controller-equipped viscometer (TVE-35H manufactured by Toki Sangyo K. K.) at 23 ° C. It measured using a measurable rotational speed and a cone rotor, and performed shear rate dependence evaluation.
Specifically, the viscosity ηa (mPa · s) at the measurement rotation speed a (rpm) and the viscosity ηb (mPa · s) at the measurement rotation speed b (rpm) are measured (where a * 10 = b There was a) TI, which is represented by the following equation.
TI = ηa / ηb
Specific examples of measurable rotational speeds are, for example, 0.5, 1, 2.5, 5, 10, 20, 50, and 100 rpm.
Specific examples of measurable cone rotors are, for example, 1 ° 34 ′ (corn rotor angle) × R 24 (corn rotor diameter), 1 ° 34 ′ × R 12, 0.8 ° × R 24, 0.8 ° × R12, 3 ° × R24, 3 ° × R12, 3 ° × R17.65, 3 ° × R14, 3 ° × R12, 3 ° × R9.7.

<Coating evaluation>
The resin composition prepared in Examples and Comparative Examples was applied to a glass substrate of 300 mm * 300 mm with a coating area of 295 mm * 295 mm using a slit coater (made by SCREEN Finetech Solutions Co., Ltd.), and coating evaluation was performed. .

(Slit nozzle evaluation)
The resin composition (varnish) prepared in Examples and Comparative Examples was filled into the nozzle of a slit coater, evaluated according to the following criteria, and listed in the table.
After the discharge of the varnish from the nozzle is started and the discharge is stopped, the varnish drips down from the slit nozzle: the varnish is not discharged from the liquid leakage nozzle: clogging liquid leakage, can be coated without clogging: no problem

(Coat gap)
The film thickness of the resin composition (varnish) prepared in Examples and Comparative Examples is 10 μm after imidization (heating at 100 ° C. for 1 hour and heating at 400 ° C. for 30 minutes at an oxygen concentration of 10 mass ppm or less) The glass substrate was coated (coating speed 100 mm / sec) so as to be The coating gap set value of the slit coater at that time was described in the table.

(Edge evaluation)
The resin composition prepared in Examples and Comparative Examples is coated on a glass substrate, moved to a drying furnace and heated at 100 ° C. for 1 hour, and then the edge of the coating is observed at 10 × using an optical microscope, The following criteria were evaluated.
Further, using a stylus type profilometer (P-15: manufactured by KLA Tencor), the edge bead (the rise of the edge portion) of the coating film was measured and evaluated according to the following criteria.
Dripping with a width of 0.5 mm or more is observed by microscopic observation of the edge portion: The thickness of the bead is 30% or more of the coating film thickness in the film thickness measurement of the sag edge portion: Bead sag, edge abnormality None: No problem

(Slit coat possible)
The above-mentioned (slit nozzle evaluation), (coat gap), and (edge evaluation) were evaluated according to the following criteria and described in the table.
In the composition using the polyimide precursor of the predetermined weight average molecular weight of each example and comparative example, all the following evaluation results are satisfied with a solid content in the range of 7 to 28% by mass: In the composition using the polyimide precursor of the predetermined polymerization average molecular weight of each example and comparative example, in the range of solid content 7 to 28% by mass, all the following evaluation results can not be obtained: not possible Slit nozzle Evaluation: No problem Coat gap: 50 μm or more Edge evaluation: No problem

<Cured film thickness uniformity (standard deviation)>
The above-mentioned <coating evaluation> (coat gap) The polyimide film concerning the example and comparative example which were produced on a glass substrate (namely, the polyimide film formed 295 mm * 295 mm in a 300 mm * 300 mm glass substrate) was used. Using a glass substrate on which a polyimide film is formed, the film thickness at a distance of 20 mm from the center of the coated surface toward the end faces of MD (that is, slit coat direction) and TD (direction perpendicular to MD) (Therefore, the end is located 7.5 mm from the end face) (a total of 30 points at 15 points of MD and 15 points of TD). The film thickness was measured using a contact-type step gauge. From the results, the film thickness uniformity of the polyimide film (the standard deviation of the film thickness at 30 points) was calculated and evaluated according to the following criteria.
Good: In-plane film thickness uniformity (3 sigma) is 1.0 μm or less Possible: In-plane film thickness uniformity (3 sigma) is more than 1.0 μm 2.0 μm or less Defect: In-plane film thickness uniformity (3 sigma) Exceeds 2.0 μm

<Hardened film elongation>
The resin compositions prepared in Examples and Comparative Examples were spin-coated on a 6-inch silicon wafer substrate provided with an aluminum deposition layer on the surface to a thickness of 10 μm after curing and prebaked at 100 ° C. for 6 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 the heat curing treatment is performed at 400 ° C. for 30 minutes. Then, a wafer on which a polyimide film was formed was produced. Next, 3 mm wide cuts were made in the polyimide film of the wafer using a dicing saw (DAD 3350 manufactured by Disco Co., Ltd.), and then soaked in dilute hydrochloric acid aqueous solution overnight to peel off the film pieces and dried. This was cut into a length of 50 mm and used as a sample.

The elongation of the above sample was 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.). The following criteria were evaluated and listed in the table.
Excellent: 40% or more Good: 20% or more, less than 40% Acceptable: less than 20%

Hardened film (Haze)
The polyimide films according to the examples and comparative examples produced on the glass substrate in the above <coating evaluation> (coat gap) were used.

About the obtained sample, the measurement of the haze (10 micrometers of film thickness conversion) was performed according to JISK7105 transparency test method using SC-3H type haze meter by Suga Test Instruments Co., Ltd. product. The measurement results were evaluated according to the following criteria and listed in the table.
Excellent: Haze 0.5 or less Good: Haze greater than 0.5 and 1.5 or less acceptable: Haze greater than 1.5

<Cured film yellowness (YI)>
The polyimide films according to the examples and comparative examples produced on the glass substrate in the above <coating evaluation> (coat gap) were used. The yellowness (YI) value (film thickness converted to 10 μm) of the obtained sample was measured using a D65 light source by Nippon Denshoku Kogyo Co., Ltd. (Spectrophotometer: SE600). The results are listed in the table.

<Cured film Rth (retardation, retardation in the thickness direction)>
The polyimide films according to the examples and comparative examples produced on the glass substrate in the above <coating evaluation> (coat gap) were used. The Rth (film thickness converted to 10 μm) of the obtained sample was measured using a retardation birefringence measurement apparatus (KOBRA-WR manufactured by Oji Scientific Instruments). The wavelength of the measurement light was 589 nm. The results are listed in the table.

Comparative Example 1-1
NMP (812 g) is added to a 3 L separable flask with a stirring rod while introducing nitrogen gas, and 4,4'-DAS (4,4'-diaminodiphenyl sulfone) (14.2 g) as a diamine, TFMB (12. 2 g), both terminal amine modified methyl phenyl silicone oil (10.56 g) was added with stirring, followed by PMDA (15.3 g), BPDA (8.8 g) as an acid dianhydride (acid dianhydride , Molar ratio of diamine (100: 98)). Next, the temperature was raised to 80 ° C. using an oil bath, and after stirring for 4 hours, the oil bath was removed and the temperature was returned to room temperature to obtain an NMP solution of transparent polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer (setting −20 ° C., the same applies hereinafter), and was thawed and used for evaluation.

<Comparative Examples 1-2 to 1-6>
The same procedure as in Comparative Example 1-1 was repeated except that the solid content in Table 1 was changed by changing the amount of NMP.

Example 1-1
In a 3 L separable flask with stir bar, while introducing nitrogen gas, as diamine, 4,4'-DAS (15.3 g) and TFMB (12.4 g), and twice the mass of the total mass of these diamines The polymerization solvent (NMP) was added.
Next, the dropping funnel was set in the above separable flask, and while introducing nitrogen gas into the dropping funnel, PMDA (15.3 g) and BPDA (8.8 g) as acid dianhydride, and these acid dianhydrides were prepared. Two times the mass of polymerization solvent (NMP) was added. And it stirred with the small stirring blade at room temperature.
Subsequently, another dropping funnel is set in the above separable flask, and while introducing nitrogen gas into the dropping funnel, the both terminal amine modified methylphenyl silicone oil X-22-1660B-3 (10.56 g) as the diamine and the said Two times the weight of the silicone oil polymerization solvent (NMP) was added. And it stirred with the small stirring blade at room temperature.
Then, while stirring the diamine solution in the separable flask, while the small stirring blade of the dropping funnel was being stirred at room temperature, dropping of the acid dianhydride solution and the silicone oil was simultaneously started. The dropping was all performed at low speed, and was dropped over 30 minutes. After the dropwise addition, the resultant was washed with a washing solvent (NMP), and the residue was dropped (molar ratio of acid dianhydride to diamine (100: 99)).
Thereafter, additional solvent (NMP) was added to make the final solid content shown in Table 1. Subsequently, the mixture was stirred at room temperature for 30 minutes and then heated to 70 ° C. using an oil bath and stirred for 4 hours. Thereafter, the oil bath was removed, and the temperature was returned to room temperature to obtain a transparent polyamic acid in NMP solution (hereinafter also referred to as a varnish). The obtained varnish was stored in a freezer (setting −20 ° C., the same applies hereinafter), and was thawed and used for evaluation.

Examples 1-2 to 1-17, 2-1 to 2-14, 3-1 to 3-16, 4-1 to 4-12>
The combinations of acid dianhydride and diamine are as shown in Tables 1 to 4, and accordingly, the amount of polymerization solvent used is changed (that is, adjusted to be twice the mass of acid dianhydride or diamine). Further, for Examples 1-5 to 1-8, 2-5 to 2-14, 3-3 to 3-16, and 4-5 to 4-12, “heat to 70 ° C. and stir for 4 hours” Change the temperature to 40 ° C and stir for 12 hours. For Examples 1-9, 2-9, 3-9, and 4-9, add the additional solvent (NMP) to the additional solvent (NMP and GBL). The conditions were the same as in Example 1-1, except that the NMP / GBL after addition was adjusted to be 100/100 (w / w). The solid contents shown in Tables 1 to 4 were adjusted to the values shown in the table by changing the amount of the additional solvent. In Examples 1-16, 2-12, 2-13, 3-14, 3-15, 4-10, and 4-11, the weight average molecular weight was measured after "stirring for 12 hours" and further extending the reaction time. As a result, it did not become larger than after stirring for 12 hours.

<Comparative Examples 2-1 to 2-6, 3-1 to 3-6, 4-1 to 4-7>
In Comparative Examples 2-1, 3-1, and 4-1, the amount of NMP of Comparative Example 1-1 is 745 g (Comparative Example 2-1), 799 g (Comparative Example 3-1), and 850 g (Comparative Example 4-1). The reaction was conducted in the same manner as in Comparative Example 1-1 except that the acid dianhydride and the diamine were blended as shown in Table 2, respectively. In addition, Comparative Examples 2-2 to 2-6 are Comparative Example 2-1 and Comparative Examples 3-2 to 3-6 except that the NMP amount is changed to obtain the solid contents in Tables 2 to 4. Comparative Example 3-1 and Comparative Examples 4-2 to 4-7 were respectively performed in the same manner as Comparative Example 4-1.

Comparative Example 5-1
NMP (620 g) is added to a 3 L separable flask with stir bar while introducing nitrogen gas, 4,4'-DAS (24.8 g) as a diamine is added with stirring, followed by PMDA (acid dianhydride). 21.8 g) were added (molar ratio of acid dianhydride to diamine (100: 100)). Next, the temperature was raised to 80 ° C. using an oil bath, and after stirring for 4 hours, the oil bath was removed and the temperature was returned to room temperature to obtain an NMP solution of transparent polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and thawed for evaluation.

<Comparative Examples 5-2 to 5-6>
The same procedure as in Comparative Example 5-1 was repeated except that the solid content in Table 5 was changed by changing the amount of NMP.

Example 5-1
In a 3 L separable flask equipped with a stir bar, while introducing nitrogen gas, 4,4′-DAS (24.3 g) as diamine and 2 times the mass of NMP of the total mass of diamine were added.
Next, the dropping funnel was set in the above separable flask, and while introducing nitrogen gas into the dropping funnel, PMDA (10.9 g) and BPDA (14.7 g) as acid dianhydrides, and 2 of these acid dianhydrides Double mass of NMP was added. And it stirred with the small stirring blade at room temperature.
Then, while stirring the diamine solution in the separable flask, dropping of the acid dianhydride solution was started while stirring the small stirring blade of the dropping funnel at room temperature. The dropping was performed at a low speed, and was dropped over 30 minutes. After the dropwise addition, the residue was washed with a washing solvent (NMP), and the residue was dropped (molar ratio of acid dianhydride to diamine (100: 98)).
Thereafter, additional solvent (NMP) was added to make the solid content in Table 5 finally. Subsequently, the mixture was stirred at room temperature for 30 minutes and then heated to 70 ° C. using an oil bath and stirred for 4 hours. Thereafter, the oil bath was removed, and the temperature was returned to room temperature to obtain a transparent polyamic acid in NMP solution (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer (setting −20 ° C., the same applies hereinafter), and was thawed and used for evaluation.

Examples 5-2 to 5-9, 6-1 to 6-9, 7-1 to 7-4, 8-1, 8-2>
The formulations of acid dianhydride and diamine were as shown in Tables 5 to 9, and accordingly, the amount of polymerization solvent used was changed (that is, adjusted to be twice the mass of acid dianhydride or diamine). Further, for Examples 5-3 to 5-9, 6-5 to 6-9, 7-4, 8-1, and 8-2, "the temperature is raised to 70 ° C. and stirring for 4 hours" The temperature was changed to “12 ° C and stirring for 12 hours”, and the “additional solvent (NMP)” was added to “additional solvent (NMP and GBL)” (NMP / GBL after addition for Examples 5-7, 6-4 and 7-4) Was adjusted to 100/100 (w / w) in the same manner as in Example 5-1 except that it was changed to 100/100 (w / w). The solid contents shown in Tables 5 to 9 were adjusted to the values shown in the table by changing the amount of the additional solvent. In Examples 5-8, 5-9, and 6-6 to 6-9, when the reaction time was extended after “stirring for 12 hours”, the weight average molecular weight was measured, which was larger than after stirring for 12 hours. It never happened.

<Comparative Examples 6-1 to 6-6, 7-1 to 7-8, 8-1 to 8-2>
In Comparative Examples 6-1, 7-1, and 8-1 to 8-2, the amount of NMP of Comparative Example 5-1 was 664 g (Comparative Example 6-1), 718 g (Comparative Example 7-1), and 401 g (Comparative Example). 8-1) Changed to 344 g (Comparative Example 8-2) respectively, and carried out in the same manner as Comparative Example 5-1 except that the blending of the acid dianhydride and the diamine was as shown in Tables 6 to 8 . Comparative Examples 6-2 to 6-6 are performed in the same manner as Comparative Example 6-1 except that the solid content in Table 6 is changed by changing the amount of NMP, and Comparative Examples 7-2 to 7-6 are NMP. The procedure of Comparative Example 7-1 was repeated except that the amount was changed to obtain the solid content in Table 7. In Comparative Examples 7-7 and 7-8, the amount of NMP was changed from 718 g to 215 g (Comparative Example 7-7) and 163 g (Comparative Example 7-8), respectively, and the composition of acid dianhydride and diamine was as shown in Table 7. As shown, the same procedure as in Comparative Example 7-1 was performed except that “stirring for 4 hours” was changed to “stirring for 3 hours”.

<Comparative Example 9-1>
NMP (495 g) is added to a 3 L separable flask with a stir bar while introducing nitrogen gas, TFMB (30.9 g) as a diamine is added with stirring, and then BPAF (9, 9-bis as acid dianhydride is added (3,4-Dicarboxyphenyl) fluorene dianhydride (45.8 g), both terminal amine modified methyl phenyl silicone oil was added X-22-1660 B-3 (10.56 g) (acid dianhydride, Molar ratio of diamine (100: 99)). Next, the temperature was raised to 80 ° C. using an oil bath, and after stirring for 4 hours, the oil bath was removed and the temperature was returned to room temperature to obtain an NMP solution of transparent polyamic acid (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer and thawed for evaluation.

Comparative Examples 9-2 to 9-3
Comparative Example except that the amount of NMP was changed from 495 g to 438 g (Comparative Example 9-2) and 374 g (Comparative Example 9-3), respectively, and the composition of the acid dianhydride and the diamine was as shown in Table 9. It went in the same way as 9-1.

Example 9-1
In a 3 L separable flask with a stirring rod, TFMB (31.3 g) as a diamine and NMP (63 g) twice as much as the total mass of the diamine were added while introducing nitrogen gas.
Next, the dropping funnel was set in the above separable flask, and while introducing nitrogen gas into the dropping funnel, BPAF (45.8 g) as acid dianhydride and NMP (92 g) twice the mass of this acid dianhydride were added. Was added. And it stirred with the small stirring blade at room temperature.
Subsequently, another dropping funnel is set in the separable flask, and while introducing nitrogen gas into the dropping funnel, the both terminal amine modified methylphenyl silicone oil X-22-1660B-3 (10.56 g) and the silicone oil Two times the mass of NMP (21 g) was added. And it stirred with the small stirring blade at room temperature.
Then, while stirring the diamine solution in the separable flask, dropping of the acid dianhydride solution was started while stirring the small stirring blade of the dropping funnel at room temperature. The dropping was performed at a low speed, and was dropped over 30 minutes. After dropping, the residue was washed with a washing solvent (NMP), and the residue was dropped (molar ratio of acid dianhydride to diamine (100: 100)).
Thereafter, additional solvent (NMP) was added to make the solid content of Table 9 finally.
Subsequently, the mixture was stirred at room temperature for 30 minutes and then heated to 40 ° C. using an oil bath and stirred for 12 hours. Thereafter, the oil bath was removed, and the temperature was returned to room temperature to obtain a transparent polyamic acid in NMP solution (hereinafter also referred to as varnish). The obtained varnish was stored in a freezer (setting −20 ° C., the same applies hereinafter), and was thawed and used for evaluation.

Examples 9-2 and 9-3
The composition of acid dianhydride and diamine was as shown in Table 9, and the amount of polymerization solvent used was changed accordingly (ie, adjusted to be twice the mass of acid dianhydride or diamine) Others were performed in the same manner as in Example 9-1. The solid content shown in Table 9 was adjusted to the values shown in the table by changing the amount of the additional solvent.

Example 10-1
NMP (246 g) is added to a 3 L separable flask with a stirring rod while introducing nitrogen gas, and 4,4'-DAS (14.4 g) and TFMB (12.4 g) as diamines are modified with amine-modified methyl phenyl silicone Oil (10.56 g) was added with stirring, followed by PMDA (15.3 g) and BPDA (8.8 g) as acid dianhydride (molar ratio of acid dianhydride and diamine (100: 99) ). Next, the temperature was raised to 70 ° C. using an oil bath, and after stirring for 8 hours, the oil bath was removed and the temperature was returned to room temperature to obtain an NMP solution of transparent polyamic acid. The obtained varnish was stored in a freezer (setting −20 ° C., the same applies hereinafter), and was thawed and used for evaluation.

Examples 10-2 to 10-5
The amount of NMP was changed from 246 g to 225 g (Example 10-2), 242 g (Example 10-3), 185 g (Example 10-4), 201 g (Example 10-5), respectively, and acid dianhydride and The procedure of Example 10-1 was repeated except that the diamine composition was as shown in Table 10.
The results of the evaluation are shown in Table 10.

The resin composition of the present disclosure can be suitably applied to applications such as flexible devices (for example, flexible substrates), particularly flexible displays. For example, the resin composition of the present disclosure can be suitably used to form a transparent substrate of a display device such as a liquid crystal display, an organic electroluminescence display, a field emission display, an electronic paper and the like. More specifically, the resin composition of the present disclosure 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.

2a lower substrate 2b sealing substrate 25 organic EL structure 250a organic EL element 250b emitting red light organic EL element 250c emitting green light organic EL element emitting blue light 251 partition wall (bank)
252 Lower electrode (anode)
253 hole transport layer 254 light emitting layer 255 top electrode (cathode)
256 TFT
257 contact hole 258 interlayer insulating film 259 lower electrode 261 hollow portion

Claims

Following formula (1):

In the formula, when there are a plurality of R 1 's each independently represent a divalent organic group, and when there are a plurality of R 2' s each represent a tetravalent organic group independently, n is a positive integer. A resin composition comprising a polyimide precursor having a structure represented by
The weight average molecular weight of the polyimide precursor is 110,000 to 250,000,
A resin composition, wherein the solid content of the resin composition is 10 to 25% by mass.
The shear rate dependency (TI) represented by the following equation is 0.9 to 1.1 when the viscosity of the resin composition is measured at 23 ° C. with a thermostat and viscometer. The resin composition as described in 1.
TI = ηa / ηb
{Wherein ηa (mPa · s) is the viscosity at the measured rotational speed a (rpm) of the resin composition, and ηb (mPa · s) is the viscosity at the measured rotational speed b (rpm) of the resin composition, However, it is a * 10 = b. }
The resin composition according to claim 1, wherein the resin composition is a resin composition for slit coat.
At least one of R 1 in the formula (1) is represented by the following formula (2):

The resin composition according to any one of claims 1 to 3, which is a group represented by
The polyimide precursor is represented by the following formula (3):

[Wherein, each of R 3 and R 4 independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a monovalent aromatic group having 6 to 10 carbon atoms, when there are a plurality of each. , And m is an integer of 1 to 200. The resin composition according to any one of claims 1 to 4, which has a structure represented by
The resin composition according to any one of claims 1 to 5, wherein the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride containing pyromellitic dianhydride and diamine.
The copolymer according to any one of claims 1 to 6, wherein the polyimide precursor is a copolymer of tetracarboxylic acid dianhydride containing 3,3 ', 4,4'-biphenyltetracarboxylic acid dianhydride and diamine. The resin composition as described in a term.
The polyimide precursor is a copolymer of tetracarboxylic dianhydride and diamine, and the tetracarboxylic dianhydride is pyromellitic dianhydride and 3,3 ', 4,4'-biphenyltetra The carboxylic acid dianhydride is contained at a molar ratio of 20:80 to 80:20 of the pyromellitic dianhydride and the 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. The resin composition according to any one of to 7.
The polyimide precursor includes tetracarboxylic acid dianhydride, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 2,2′-bis (trifluoromethyl) benzidine and 9,9-bis The resin composition according to any one of claims 1 to 8, which is a copolymer with one or more diamines selected from the group consisting of (4-aminophenyl) fluorene.
The resin composition according to any one of claims 1 to 9, wherein the weight average molecular weight of the polyimide precursor is 160,000 to 220,000.
The resin composition according to any one of claims 1 to 10, wherein the resin composition is a resin composition for a flexible device.
The resin composition according to any one of claims 1 to 11, wherein the resin composition is a resin composition for a flexible display.
A polyimide film which is a cured product of the resin composition according to any one of claims 1 to 12.
The polyimide film according to claim 13, wherein retardation in a thickness direction (Rth) in terms of a film thickness of 10 μm is 300 or less and / or a yellowness (YI) in terms of a film thickness of 10 μm is 20 or less.
A flexible device comprising the polyimide film according to claim 13 or 14.
A flexible display comprising the polyimide film according to claim 13 or 14.
The flexible display according to claim 16, wherein the polyimide film is disposed at a location that is viewed when the flexible display is observed from the outside.
An applying step of applying the resin composition according to any one of claims 1 to 12 on the surface of a support;
A film forming step of heating the resin composition to form a polyimide film;
And a peeling step of peeling the polyimide film from the support.
The method for producing a polyimide film according to claim 18, wherein the applying step includes slit coating the resin composition.
At least one of R 1 in the formula (1) is represented by the following formula (2):

The manufacturing method of the polyimide film of Claim 19 which is group represented by these.
The polyimide precursor is represented by the following formula (3):

[Wherein, each of R 3 and R 4 independently represents a monovalent aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a monovalent aromatic group having 6 to 10 carbon atoms, when there are a plurality of each. , And m is an integer of 1 to 200. The manufacturing method of the polyimide film of Claim 19 or 20 which has a structure represented by}.
The method for producing a polyimide film according to any one of claims 18 to 21, further comprising an irradiation step of irradiating a laser onto the polyimide film from the support side prior to the peeling step.
An applying step of applying the resin composition according to any one of claims 1 to 12 on the surface of a support;
A film forming step of heating the resin composition to form a polyimide film;
An element forming step of forming an element on the polyimide film;
And a peeling step of peeling the polyimide film on which the element is formed from the support.
The method for manufacturing a display according to claim 23, wherein the applying step comprises slit coating the resin composition.
The method for manufacturing a display according to claim 23, wherein the polyimide film is disposed at a position where the display is viewed when the display is observed from the outside.