阅读说明：本技术 用于耐热电子装置的基材 (Substrate for heat-resistant electronic device ) 是由 朴永善 白木真司 于 2020-03-30 设计创作，主要内容包括：本公开内容提出了用于电子装置的改进的耐热基材,所述用于电子装置的改进的耐热基材具有透明性、耐热性和机械强度并且还具有优异的光学特性和品质,从而能够代替透明玻璃基板。本公开内容通过包含基于聚酰亚胺的树脂和中空颗粒的用于电子装置的耐热基材来实现,其中多个中空颗粒分散并存在于基于聚酰亚胺的树脂中,并且中空颗粒的平均粒径大于或等于10nm且小于或等于300nm。(The present disclosure proposes an improved heat-resistant substrate for an electronic device, which has transparency, heat resistance and mechanical strength and also has excellent optical characteristics and quality, thereby being capable of replacing a transparent glass substrate. The present disclosure is achieved by a heat-resistant base material for an electronic device comprising a polyimide-based resin and hollow particles, wherein a plurality of the hollow particles are dispersed and present in the polyimide-based resin, and an average particle diameter of the hollow particles is greater than or equal to 10nm and less than or equal to 300 nm.)

1. A heat resistant substrate for an electronic device, the substrate comprising:

a polyimide-based resin; and

the hollow particles are formed by the reaction of a hollow particle,

wherein a plurality of the hollow particles are dispersed and present in the polyimide-based resin; and is

The hollow particles have an average particle diameter of 10nm or more and 300nm or less.

2. The heat-resistant substrate for electronic devices according to claim 1, wherein the polyimide-based resin is a modified polyimide comprising a terminal group represented by the following chemical formula 1:

[ chemical formula 1]

In the chemical formula 1, the first and second,

d is a thermally or photo curable functional group;

r is a divalent or higher organic group; and

n is an integer of 1 or more.

3. The heat resistant substrate for electronic devices according to claim 2, wherein the functional group of chemical formula 1 is a thermally or photo curable functional group derived from a reaction of an acid dianhydride terminal group of polyimide with a compound of the following chemical formula 2:

[ chemical formula 2]

4. The heat-resistant substrate for electronic devices according to claim 2, wherein the polyimide-based resin is a modified polyimide obtained from 2,2' -bis (trifluoromethyl) -4,4' -diaminobiphenyl (TFMB) and 4,4' -oxydiphthalic anhydride (ODPA).

5. The heat-resistant substrate for electronic devices according to claim 1, wherein the polyimide-based resin is a polyimide-based resin obtained from a polyimide comprising a structure of the following chemical formula a and a polyamic acid comprising a structure of the following chemical formula B:

[ chemical formula A ]

[ chemical formula B ]

In the chemical formulae a and B,

x is a tetravalent organic group from an acid dianhydride; and

y is a divalent organic group derived from a diamine.

6. The heat-resistant substrate for electronic devices according to claim 5, wherein in chemical formula A and chemical formula B,

x is formed to include a tetravalent organic group having a substituent containing a fluorine atom;

y is formed to include a divalent organic group having a substituent containing a fluorine atom; alternatively, the first and second electrodes may be,

both X and Y are formed to include an organic group having a substituent containing a fluorine atom.

7. The heat-resistant substrate for an electronic device according to claim 6, wherein the divalent organic group having a substituent containing a fluorine atom is a divalent organic group obtained from 2,2' -bis (trifluoromethyl) benzidine or 2, 2-bis [4- (-aminophenoxy) phenyl ] hexafluoropropane.

8. The heat-resistant substrate for electronic devices according to claim 6, wherein, in chemical formulas A and B, X is formed by providing a structure that is a tetravalent organic group having a substituent containing a fluorine atom or a structure that is a tetravalent organic group having no substituent containing a fluorine atom.

9. The heat-resistant substrate for electronic devices according to claim 8, wherein the tetravalent organic group having no substituent containing a fluorine atom is a compound selected from the group consisting of: 3,3',4,4' -biphenyltetracarboxylic dianhydride, 2,3,3',4' -biphenyltetracarboxylic dianhydride, pyromellitic anhydride, 1,2,4, 5-cyclohexanetetracarboxylic dianhydride, 4,4' -oxydiphthalic anhydride, 2,3,3',4' -oxydiphthalic anhydride and mixtures thereof.

10. The heat-resistant substrate for electronic devices according to any one of claims 1 to 9, wherein the hollow particles are hollow silica particles.

11. The heat-resistant substrate for electronic devices according to claim 10, wherein the average primary particle diameter of the hollow silica particles is greater than or equal to 40nm and less than or equal to 150 nm.

12. The heat-resistant base material for electronic devices according to claim 1, wherein the hollow particles are hollow silica particles, and the polyimide-based resin has a refractive index of greater than or equal to 1.40 and less than or equal to 1.55 at a wavelength of 632.8nm after curing.

13. The heat-resistant substrate for electronic devices according to claim 1, which has a light transmittance of 85% or more;

1.0% or less haze;

1.0 or less of the initial color b (CIE 1976L a b in the color space);

a difference between the initial color b of 0.5 or less and the color b after 72 hours or more of exposure to an ultraviolet lamp in the UVB wavelength region; and/or the presence of a gas in the gas,

a yellowness index value "YI value" of 5.0 or less.

14. The heat-resistant substrate for electronic devices according to claim 1, which is a substrate that is a basic structure of an electronic device.

15. The heat-resistant substrate for electronic devices according to claim 1, which is a substrate as a substrate supporting a basic structure of: a display, a lens, a Thin Film Transistor (TFT), a polarizing plate, an alignment film, a color filter, an optical compensation film, an antireflection film, an antiglare film, a surface treatment film, an antistatic film, a spacer, a capacitor, a vibration element, or an actuator.

Technical Field

The present disclosure claims priority and benefit of japanese patent application No. 2019-070515, filed on day 4/2 of 2019 to the present intellectual property office, the entire contents of which are incorporated herein by reference.

The present disclosure relates to heat resistant substrates for electronic devices and methods for making the same.

Background

In various electronic devices such as mobile tools, digital cameras, and displays, which have become highly functionalized, with advances made in high performance, miniaturization, weight reduction, and flexibility, replacement from existing glass substrates to transparent polymer substrates has been recently studied.

Meanwhile, in the study of substitution for a transparent polymer base material, transparency, heat resistance and strength (which are characteristics of existing glass substrates) are also required to be considered. In particular, in flexible devices, a heat treatment of about 300 ℃ to 400 ℃ is required in Thin Film Transistor (TFT) mounting, and a transparent polymer substrate having such excellent high heat resistance is required.

In the art, for example, transparent polyimide resins such as fluorinated polyimide resins, semi-alicyclic or full-alicyclic polyimide resins are proposed in patent document 1 (Japanese unexamined patent application publication No. H11-106508), patent document 2 (Japanese unexamined patent application publication No. 2002-146021) and patent document 3 (Japanese unexamined patent application publication No. 2002-348374).

It is apparent that the polyimide-based polymer film proposed in the prior art has excellent transparency, heat resistance and mechanical strength, but, from the general characteristics of organic polymer materials, undergoes thermal decomposition when exposed to high temperatures of 320 ℃ or more, which sometimes impairs the function as a transparent substrate, and a function such as transparency is sometimes impaired by the occurrence of discoloration (in particular, discoloration into yellow or dark brown).

BRIEF SUMMARY OF THE PRESENT DISCLOSURE

Technical problem

Therefore, there is still a need to develop an improved high heat-resistant substrate for electronic devices having transparency, heat resistance and mechanical strength and also having excellent optical characteristics and quality so as to be able to replace the transparent glass substrate.

Technical scheme

The present disclosure is based on the following findings: by being formed of a specific polyimide-based resin and hollow particles dispersed therein, an improved (highly) heat-resistant substrate for electronic devices can be proposed which has transparency, heat resistance and mechanical strength and also has excellent optical characteristics and quality, thereby being capable of replacing a transparent glass substrate.

[ one aspect of the present disclosure ]

One aspect of the disclosure is as follows.

[1] A heat resistant substrate for an electronic device, the substrate comprising:

a resin based on polyimide and hollow particles,

wherein a plurality of hollow particles are dispersed and present in the polyimide-based resin, and

the hollow particles have an average particle diameter of 10nm or more and 300nm or less.

[2] The heat-resistant substrate for an electronic device described in [1], wherein the polyimide-based resin is a modified polyimide comprising a terminal group represented by the following chemical formula 1.

< chemical formula 1> (described below)

[ in the chemical formula 1,

d is a thermally or photo-curable functional group,

r is a divalent or higher organic group, and

n is an integer of 1 or more. ]

[3] The heat-resistant substrate for electronic devices as described in [2], wherein the functional group of chemical formula 1 is a thermally or photo-curable functional group derived from the reaction of an acid dianhydride terminal group of polyimide with a compound of the following chemical formula 2.

< chemical formula 2> (described below)

[4] The heat-resistant substrate for electronic devices as described in [2] or [3], wherein the polyimide-based resin is a modified polyimide obtained from 2,2' -bis (trifluoromethyl) -4,4' -diaminobiphenyl (TFMB) and 4,4' -oxydiphthalic anhydride (ODPA).

[5] The heat-resistant substrate for electronic devices according to [1], wherein the polyimide-based resin is a polyimide-based resin obtained from a polyimide comprising a structure of the following chemical formula A and a polyamic acid comprising a structure of the following chemical formula B.

< chemical formula A > (described below)

< chemical formula B > (described below)

[ in the chemical formulas A and B,

x is a tetravalent organic group derived from an acid dianhydride, and

y is a divalent organic group derived from a diamine. ]

[6] The heat-resistant substrate for electronic devices as described in [5], wherein, in the chemical formula A and the chemical formula B,

x is formed to include a tetravalent organic group having a substituent containing a fluorine atom,

y is formed to include a divalent organic group having a substituent containing a fluorine atom, or,

both X and Y are formed to include an organic group having a substituent containing a fluorine atom.

[7] The heat-resistant substrate for an electronic device according to [6], wherein the divalent organic group having a substituent containing a fluorine atom is a divalent organic group obtained from 2,2' -bis (trifluoromethyl) benzidine or 2, 2-bis [4- (-aminophenoxy) phenyl ] hexafluoropropane.

[8] The heat-resistant substrate for an electronic device according to [6], wherein, in the chemical formulas A and B, X is formed by providing a structure that is a tetravalent organic group having a substituent containing a fluorine atom or a structure that is a tetravalent organic group having no substituent containing a fluorine atom.

[9] The heat-resistant substrate for an electronic device described in [8], wherein the tetravalent organic group having no substituent containing a fluorine atom is a compound selected from the group consisting of: 3,3',4,4' -biphenyltetracarboxylic dianhydride, 2,3,3',4' -biphenyltetracarboxylic dianhydride, pyromellitic anhydride, 1,2,4, 5-cyclohexanetetracarboxylic dianhydride, 4,4' -oxydiphthalic anhydride, 2,3,3',4' -oxydiphthalic anhydride and mixtures thereof.

[10] The heat-resistant base material for an electronic device as described in any one of [1] to [9], wherein the hollow particles are hollow silica particles.

[11] The heat-resistant base material for electronic devices described in [10], wherein the average primary particle diameter of the hollow silica particles is greater than or equal to 40nm and less than or equal to 150 nm.

[12] The heat-resistant base material for electronic devices described in any one of [1] to [11], wherein the hollow particles are hollow silica particles, and the refractive index of the polyimide-based resin after curing at a wavelength of 632.8nm is greater than or equal to 1.40 and less than or equal to 1.55.

[13] The heat-resistant substrate for electronic devices described in any one of [1] to [12], which has a light transmittance of 85% or more,

a haze of 1.0% or less,

1.0 or less of the initial color b (CIE 1976L a b in the color space),

a difference between an initial color b of 0.5 or less and a color b after 72 hours or more of exposure to an ultraviolet lamp in the UVB wavelength region, and/or

A yellowness index value "YI value" of 5.0 or less.

[14] The heat-resistant substrate for an electronic device according to any one of [1] to [13], which is a substrate as a basic structure of an electronic device.

[15] The heat-resistant substrate for electronic devices described in any one of [1] to [14], which is a substrate as a substrate supporting a basic structure of: a display, a lens, a Thin Film Transistor (TFT), a polarizing plate, an alignment film, a color filter, an optical compensation film, an antireflection film, an antiglare film, a surface treatment film, an antistatic film, a spacer, a capacitor, a vibration element, or an actuator.

Advantageous effects

The present disclosure can propose a heat-resistant substrate for electronic devices capable of sufficiently exhibiting the performance as an optical functional material, particularly an electronic device functional material, by having transparency, heat resistance, mechanical strength and flexibility and also by maintaining transparency without exhibiting discoloration even in a high-temperature region.

Detailed Description

[ Heat-resistant base Material for electronic device ]

"heat-resistant substrate for electronic device" is a substrate itself as a basic structure used in an electronic device. Therefore, the substrate itself is not a functional thin film (layer) itself exhibiting the functions of a polarizing plate, an alignment film, a color filter, an optical compensation film, an antireflection film, an antiglare film, a surface treatment material, an antistatic layer, a spacer, a capacitor, a vibration element, an actuator, and the like. The present disclosure is directed to the substrate itself supporting such an electrochemically, optically functional, electronic component-like functional film (layer).

(basic structure)

The heat-resistant base material for an electronic device of the present disclosure is formed into a structure in which hollow particles are dispersed and present in a cured polyimide-based resin matrix.

(polyimide-based resin)

In the present disclosure, a polyimide-based resin is used. Polyimide is a generic term for polymers containing imide bonds in the repeating unit, and generally means an aromatic polyimide in which aromatic compounds are directly bonded through imide bonds. Specifically, the polyimide is generally represented by the following chemical formula (X) (in the formula X, n is 1 to 100,000).

NCOCORCOCONR' (X)

Polyimide is generally prepared by preparing a polyamic acid as a precursor material from a diamine compound and a carboxylic acid anhydride (R-CO-O-CO-R'), heating, and imidizing the resultant. In the present disclosure, various polyimide-based resins may be used within the scope of the object of the present disclosure.

In the present disclosure, a modified polyimide including a terminal group represented by the following chemical formula 1 may be used as the polyimide-based resin.

[ chemical formula 1]

[ in the chemical formula 1,

d is a thermally or photo-curable functional group,

r is a divalent or higher organic group, and

n is an integer of 1 or more. ]

The functional group of chemical formula 1 is a thermally or photo curable functional group derived from the reaction of the compound of chemical formula 2 below with the terminal group of the acid dianhydride of polyimide.

[ chemical formula 2]

Here, the heat-curable or light-curable functional group represented by D is one or more functional groups selected from the group consisting of: vinyl group, alkyl group, acrylate group, carboxyl group, amide group, amino group, epoxy group, isocyanate group, cyano group, acid anhydride group, mercapto group, silanol group, alkoxysilane group, hydroxyl group andthe oxazoline group is preferably selected from the group consisting of an acrylate group, an epoxy group, an isocyanate group and a mercapto group, and more preferably an acrylate group.

More specifically, chemical formula 2 is a compound selected from the following chemical formulae 2a to 2c, preferably a compound modified with acryl and isocyanate of chemical formula 2 a.

< chemical formula 2a >

< chemical formula 2b >

< chemical formula 2c >

O＝C＝N-R₅-SH

[ in chemical formulas 2a to 2c,

R₁、R₃and R₅Is an alkylene group having 1 to 18 carbon atoms or an arylene group having 6 to 24 carbon atoms, or a divalent organic group thereof is bonded by an ether bond, an ester bond, a urethane bond, an amide bond, a siloxane bond or a silazane bond, and

at least one hydrogen contained in the divalent organic group is unsubstituted or substituted with a substituent selected from the group consisting of: halogen atoms, alkyl groups having 1 to 10 carbon atoms, haloalkyl groups, cycloalkyl groups having 3 to 30 carbon atoms, aryl groups having 6 to 30 carbon atoms, hydroxyl groups, alkoxy groups having 1 to 10 carbon atoms, carboxylic acid groups, aldehyde groups, epoxy groups, cyano groups, nitro groups, amino groups, sulfonic acid groups and derivatives thereof, preferably substituted by halogen atoms, alkyl groups having 1 to 10 carbon atoms or haloalkyl groups, and R₂And R₄Is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms.]

In accordance with the present disclosure, the modified polyimide is prepared using the following method: reacting tetracarboxylic dianhydride and diamine in a polymerization solvent to polymerize polyamic acid,

imidizing the polyamic acid to prepare a polyimide of chemical formula 3 having an acid dianhydride group at the end, and

the polyimide of chemical formula 3 is reacted with the compound of chemical formula 2 below to prepare a polyimide compound of chemical formula 4 including a curable functional group at a terminal.

< chemical formula 2>

< chemical formula 3>

< chemical formula 4>

[ in the chemical formulae 2 to 4,

d is a thermally or photo-curable functional group,

r is a divalent or higher organic group,

n is an integer of 1 or more,

X₁、X₂、X₃and X₄Each independently a tetravalent organic group derived from a tetracarboxylic dianhydride,

Y₁、Y₂and Y₃Each independently a divalent organic group derived from a diamine,

w and z are each independently an integer of 1 or more,

p, q, r and v are each independently an integer of 0 or more, but not simultaneously 0, and

the value of p + q + r + v is less than or equal to the value of w + z.

In chemical formula 4, p + q + r + v is an integer of 2 to 100. ]

In other words, the isocyanate group of chemical formula 2 reacts not only with the dianhydride group at the terminal of the polyimide but also with the imide group contained in the main chain of the polyimide, which causes the imide group in the main chain to be opened, and thus, an organic group having a curable functional group bonded at the terminal may be bonded to the side chain of the opened polyimide.

In addition, the polyimide of the present disclosure further includes a repeating structure represented by the following chemical formulae 5a to 5c in the main chain.

< chemical formula 5a >

< chemical formula 5b >

< chemical formula 5c >

In chemical formulas 5a to 5c, R_a、R_b、R_c、R_d、R_eAnd R_fEach selected from aromatic, alicyclic and aliphatic divalent organic groups, specifically selected from divalent aromatic organic groups of the following chemical formulae 9a to 9d, and more specifically selected from divalent aromatic organic groups of the following chemical formulae 10a to 10 p.

X₁、X₂、X₃And X₄Is a tetravalent organic group derived from a dianhydride, and more preferably a tetracarboxylic dianhydride comprising an aromatic tetravalent organic group.

The tetracarboxylic dianhydride which can be used to prepare the polyimide of chemical formula 3 is a tetracarboxylic dianhydride comprising the functional group X of chemical formula 3₁、X₂、X₃And X₄For example, a tetracarboxylic dianhydride comprising a tetravalent organic group in which a monocyclic aromatic group, a polycyclic aromatic group or a combination thereof group in the molecule is linked to each other through a crosslinking structure.

Specifically, X₁、X₂、X₃And X₄An aromatic tetravalent organic group selected from the following chemical formulas 7a to 7 d.

< chemical formula 7a >

< chemical formula 7b >

< chemical formula 7c >

< chemical formula 7d >

In the chemical formulae 7a to 7d,

R₁₁to R₁₅Each independently an alkyl group having 1 to 10 carbon atoms or a fluoroalkyl group having 1 to 10 carbon atoms,

a2 is an integer of 0 or 2, b2 is an integer of 0 to 4, c2 is an integer of 0 to 8, d2 and e2 are each independently an integer of 0 to 3 and f2 is an integer of 0 to 3, A₁₁Selected from single bonds, -O-, -CR₁₈R₁₉-、-C(＝O)-、-C(＝O)NH-、-S-、-SO₂-, phenylene, and combinations thereof. Herein, R is₁₈And R₁₉Each independently selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms.

More specifically, X₁、X₂、X₃And X₄Is a tetravalent organic group selected from the following chemical formulas 8a to 8l, but is not limited thereto.

< chemical formula 8a >

< chemical formula 8b >

< chemical formula 8c >

< chemical formula 8d >

< chemical formula 8e >

< chemical formula 8f >

< chemical formula 8g >

< chemical formula 8h >

< chemical formula 8i >

< chemical formula 8j >

< chemical formula 8k >

< chemical formula 8l >

In chemical formula 8l, A₂Selected from the group consisting of a single bond, -O-, -C (═ O) -, -C (═ O) NH-, -S-, -SO₂-, phenylene, and combinations thereof, and v is an integer of 0 or 1.

Further, in the aromatic tetravalent organic groups of chemical formulae 8a to 8l, one or more hydrogen atoms present in the tetravalent organic group may be substituted with a substituent such as: an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, etc.) or a fluoroalkyl group having 1 to 10 carbon atoms (e.g., fluoromethyl, perfluoroethyl, trifluoromethyl, etc.).

At the same time, Y₁、Y₂And Y₃Is a diamine-based compound comprising a divalent organic group.

Specifically, Y₁、Y₂And Y₃May be an aromatic divalent organic group derived from an aromatic diamine-based compound; or divalent organic groups in which aliphatic, alicyclic, or aromatic divalent organic groups are bonded directly or to each other through a crosslinking structure as a combined group. More specifically, Y₁、Y₂And Y₃A functional group selected from the following chemical formulae 9a to 9d, and a combination thereof.

< chemical formula 9a >

< chemical formula 9b >

< chemical formula 9c >

< chemical formula 9d >

In the chemical formulae 9a to 9d,

R₅₁to R₅₅Each independently selected from the group consisting of an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, t-butyl, pentyl, hexyl, etc.), a fluoroalkyl group having 1 to 10 carbon atoms (e.g., fluoromethyl, perfluoroethyl, trifluoromethyl, etc.), an aryl group having 6 to 12 carbon atoms (e.g., phenyl, naphthyl, etc.), a sulfonic acid group and a carboxylic acid group,

a3, d3 and e3 are each independently an integer from 0 to 4, b3 is an integer from 0 to 6, and c3 is an integer from 0 to 3, and

A₂₁selected from single bonds, -O-, -CR₅₆R₅₇-、-C(＝O)-、-C(＝O)NH-、-S-、-SO₂-, phenylene, and combinations thereof. Herein, R is₅₆And R₅₇Each independently selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, etc.), and a fluoroalkyl group having 1 to 10 carbon atoms (e.g., fluoromethyl, perfluoroethyl, trifluoromethyl, etc.).

Here, the inclusion of the amino group at the para-position is not limited to the inclusion of the amino group at the first and fourth positions in one benzene ring, and also means a structure in which the amino groups are substituted at the positions farthest from each other even when the benzene rings are fused or connected through a linking group.

More specifically, the divalent organic group containing an amino group at the para-position is selected from the following chemical formulae 10a to 10 p:

< chemical formula 10a >

< chemical formula 10b >

< chemical formula 10c >

< chemical formula 10d >

< chemical formula 10e >

< chemical formula 10f >

< chemical formula 10g >

< chemical formula 10h >

< chemical formula 10i >

< chemical formula 10j >

< chemical formula 10k >

< chemical formula 10l >

< chemical formula 10m >

< chemical formula 10n >

< chemical formula 10o >

< chemical formula 10p >

Selected from the group consisting of CR₅₆R₅₇-、-C(＝O)-、-C(＝O)NH-、-S-、-SO₂-, phenylene, and combinations thereof. In this case, the amount of the solvent to be used,R₅₆and R₅₇Each independently selected from a hydrogen atom, an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, etc.), and a fluoroalkyl group having 1 to 10 carbon atoms (e.g., fluoromethyl, perfluoroethyl, trifluoromethyl, etc.). v is an integer of 0 or 1.

Further, one or more hydrogen atoms in the divalent functional groups of chemical formulas 10a to 10p may be substituted with a substituent selected from the group consisting of: an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, t-butyl, pentyl, hexyl, etc.), a fluoroalkyl group having 1 to 10 carbon atoms (e.g., fluoromethyl, perfluoroethyl, trifluoromethyl, etc.), an aryl group having 6 to 12 carbon atoms (e.g., phenyl, naphthyl, etc.), a sulfonic acid group, and a carboxylic acid group.

The polyimide of chemical formula 3 of the present disclosure is prepared using a polymerization reaction of the above tetracarboxylic dianhydride and a diamine-based compound, and is prepared using a common polymerization reaction such as solution polymerization of the polyimide or a precursor thereof.

Specifically, when solution polymerization is used, a diamine-based compound is dissolved in the above-mentioned polymerization solvent, then acid dianhydride is added thereto, and the mixture is reacted.

The above acid dianhydride and diamine-based compound are preferably used in an appropriate reaction ratio in consideration of physical properties of the finally prepared polyimide. Specifically, the acid dianhydride is reacted in a molar ratio of 1 to 1.8, preferably used in a molar ratio of 1:1.1 to 1:1.5, and more preferably used in a molar ratio of 1:1.1 to 1:1.3, relative to 1mol of the diamine-based compound. In the present disclosure, the polyimide having a dianhydride group at the end is obtained by adding an acid dianhydride in an excess molar ratio compared to a diamine and reacting it.

(preferred aspects)

In the present disclosure, a polymer of 2,2' -bis (trifluoromethyl) -4,4' -diaminobiphenyl (TFMB) and 4,4' -oxydiphthalic anhydride (ODPA) is preferably used as the modified polyimide-based resin.

(on the other hand)

In the present disclosure, a polyimide-based resin obtained from a polyimide comprising the structure of the following chemical formula a and a polyamic acid comprising the structure of the following chemical formula B is preferably used.

< chemical formula A >

< chemical formula B >

[ in the chemical formulas A and B,

x is a tetravalent organic group derived from an acid dianhydride, and

y is a divalent organic group derived from a diamine. ]

In the present disclosure, in chemical formulas a and B, such polyimide-based resins are preferably used: wherein

X is formed to include a tetravalent organic group having a substituent containing a fluorine atom,

y is formed to include a divalent organic group having a substituent containing a fluorine atom, or,

both X and Y are formed to include an organic group having a substituent containing a fluorine atom.

The divalent organic group having a substituent containing a fluorine atom is preferably a divalent organic group obtained from 2,2' -bis (trifluoromethyl) benzidine or 2, 2-bis [4- (-aminophenoxy) phenyl ] hexafluoropropane.

Further, in chemical formulae a and B of a preferred aspect of the present disclosure, X is formed preferably including a structure of a tetravalent organic group having a substituent having a fluorine atom or a structure of a tetravalent organic group having no substituent having a fluorine atom.

The tetravalent organic group having no substituent containing a fluorine atom may be a compound selected from the group consisting of: 3,3',4,4' -biphenyltetracarboxylic dianhydride, 2,3,3',4' -biphenyltetracarboxylic dianhydride, pyromellitic anhydride, 1,2,4, 5-cyclohexanetetracarboxylic dianhydride, 4,4' -oxydiphthalic anhydride, 2,3,3',4' -oxydiphthalic anhydride and mixtures thereof.

(content)

The polyimide-based resin is contained in greater than or equal to 20 wt% and less than or equal to 90 wt%, preferably in greater than or equal to 30 wt% and less than or equal to 80 wt%, and more preferably in greater than or equal to 40 wt% and less than or equal to 70 wt%, relative to the total mass (100 wt%) of the heat-resistant base material for electronic devices. When the polyimide-based resin is included at a lower limit value of 20 wt% or more with respect to the total weight, mechanical strength such as flexibility and bending resistance of the base material can be sufficiently ensured, and when the upper limit value is 90 wt% or less, transparency can be sufficiently maintained even at high temperatures (e.g., 320 ℃ or more).

(preparation)

According to the present disclosure, the objective polyimide is prepared by preparing a polyamic acid as a precursor material from a diamine compound and a carboxylic acid anhydride (R-CO-O-CO-R'), heating, and imidizing the resultant. Modification may also be performed by modification, substitution, addition, or the like during or after polymerization. Here, a solvent, an additive such as a polymerization initiator may be used for adjustment.

< polymerization solvent >

As the polymerization solvent, those selected from the following can be specifically used as the organic solvent: ketones, such as methyl ethyl ketone or cyclohexanone; aromatic hydrocarbons such as toluene, xylene or tetramethylbenzene; glycol ethers (cellosolves) such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol diethyl ether or triethylene glycol monoethyl ether; ethyl acetate; butyl acetate; ethylene glycol monoethyl ether acetate; ethylene glycol monobutyl ether acetate; diethylene glycol monoethyl ether acetate; dipropylene glycol monomethyl ether acetate; ethanol; propanol; ethylene glycol; propylene glycol; carbitol; dimethylacetamide (DMAc); n, N-diethylacetamide; dimethylformamide (DMF)(ii) a Diethylformamide (DEF); n, N-dimethylacetamide (DMAc); n-methylpyrrolidone (NMP); n-ethyl pyrrolidone (NEP); 1, 3-dimethyl-2-imidazolidinone; n, N-dimethylmethoxyacetamide; dimethyl sulfoxide; pyridine; dimethyl sulfone; hexamethylphosphoramide; tetramethylurea; n-methyl caprolactam; tetrahydrofuran; intermediate twoAn alkane; to twoAn alkane; 1, 2-dimethoxyethane; bis (2-methoxyethyl) ether; 1, 2-bis (2-methoxyethoxy) ethane; bis [2- (2-methoxyethoxy)]An ether; and mixtures thereof, preferably comprising N, N-diethylacetamide, N-diethylformamide, N-ethylpyrrolidone or mixtures thereof.

< polymerization reaction >

Further, the polymerization reaction is preferably carried out at a temperature of 10 ℃ to 30 ℃, a temperature of 15 ℃ to 25 ℃, or stirring at room temperature for 0.5 hour to 5 hours, or 1 hour to 3 hours, followed by a temperature of 30 ℃ to 65 ℃, or a temperature of 40 ℃ to 60 ℃ for 5 hours to 50 hours, 10 hours to 40 hours, or 20 hours to 30 hours.

< end sealing agent >

When the polyamic acid or polyimide of the present disclosure is synthesized, a terminal sealant for sealing the ends of the polyimide by reacting a dicarboxylic anhydride or a monoamine at the ends of the molecule may also be added to inactivate an excess of the polyamino group or the anhydride group, preferably, the ends are sealed using a dicarboxylic anhydride.

Examples of the dicarboxylic anhydride used for sealing the end of the polyimide or polyamic acid may include phthalic anhydride, 2, 3-benzophenone dicarboxylic anhydride, 3, 4-benzophenone dicarboxylic anhydride, 2, 3-dicarboxyphenyl phenyl ether anhydride, 2, 3-biphenyl dicarboxylic anhydride, 3, 4-biphenyl dicarboxylic anhydride, 2, 3-dicarboxyphenyl phenyl sulfone anhydride, 3, 4-dicarboxyphenyl phenyl sulfone anhydride, 2, 3-dicarboxyphenyl phenyl sulfide anhydride, 1, 2-naphthalene dicarboxylic anhydride, 2, 3-naphthalene dicarboxylic anhydride, 1, 8-naphthalene dicarboxylic anhydride, 1, 2-anthracene dicarboxylic anhydride, 2, 3-anthracene dicarboxylic anhydride, 1, 9-anthracene dicarboxylic anhydride, and the like. These dicarboxylic anhydrides may have groups in the molecule which do not react with the amine or dicarboxylic anhydride.

Further, examples of the monoamine may include aniline, o-toluidine, m-toluidine, p-toluidine, 2, 3-xylidine, 2, 4-xylidine, 2, 5-xylidine, 2, 6-xylidine, 3, 4-xylidine, 3, 5-xylidine, o-chloroaniline, m-chloroaniline, p-chloroaniline, o-nitroaniline, o-bromoaniline, m-bromoaniline, o-nitroaniline, m-nitroaniline, p-nitroaniline, o-aminophenol, m-aminophenol, p-aminophenol, o-anisidine (o-anilidine), m-anisidine, p-anisidine, o-phenetole, m-phenetole, p-phenetole, o-aminobenzaldehyde, m-aminobenzaldehyde, p-aminobenzaldehyde, o-aminobenzonitrile, m-aminobenzonitrile, p-aminobenzonitrile, 2-aminobiphenyl, o-aminobenzene, o-phenetole, m-aminobenzophenone, p-phenetole, o-aminobenzonitrile, m-aminobenzonitrile, p-aminobenzonitrile, o-aminobenzene, o-aniline, 3-aminobiphenyl, 4-aminobiphenyl, 2-aminophenolphenyl ether, 3-aminophenolphenyl ether, 4-aminophenolphenyl ether, 2-aminobenzophenone, 3-aminobenzophenone, 4-aminobenzophenone, 2-aminophenolphenyl sulfide, 3-aminophenolphenyl sulfide, 4-aminophenolphenyl sulfide, 2-aminophenophenylsulfone, 3-aminophenophenylsulfone, 4-aminophenophenylsulfone, alpha-naphthylamine, beta-naphthylamine, 1-amino-2-naphthol, 2-amino-1-naphthol, 4-amino-1-naphthol, 5-amino-1-naphthol, 3-aminophenol phenylsulfenyl ether, 3-aminobenzophenone, 4-aminophenols, 3-naphthylamine, 1-amino-2-naphthol, 2-amino-1-naphthol, 4-amino-1-naphthol, 5-amino-1-naphthol, 3-naphthol, and 4-amino-1-naphthol, 5-amino-2-naphthol, 7-amino-2-naphthol, 8-amino-2-naphthol, 1-aminoanthracene, 2-aminoanthracene, 9-aminoanthracene, etc. These monoamines may have a group that does not react with the amine or dicarboxylic anhydride in the molecule.

The terminal sealant is contained at 20 parts by weight or less, preferably at 1 to 10 parts by weight, and more preferably at 1 to 5 parts by weight, relative to 100 parts by weight of the tetracarboxylic dianhydride and the diamine in total.

< imidization >

For the polyamic acid obtained as a result of the polymerization reaction, an imidization process is performed. Here, the imidization is specifically performed by chemical imidization or thermal imidization, and is preferably performed by thermal imidization.

Specifically, chemical imidization is performed while removing water using a dehydrating agent such as: acid anhydrides (e.g., acetic anhydride, propionic anhydride, or benzoic anhydride) or acid chlorides thereof; or a carbodiimide compound such as dicyclohexylcarbodiimide. Here, the dehydrating agent is preferably used in a content of 0.1 to 10mol with respect to 1mol of the above-mentioned acid dianhydride. In addition, in the chemical imidization, a heating process at a temperature of 60 ℃ to 120 ℃ may also be simultaneously performed.

Further, thermal imidization is performed by heat treatment at a temperature of 80 ℃ to 400 ℃, and here, it is more preferable to simultaneously perform a process of azeotropically removing water generated due to a dehydration reaction using benzene, toluene, xylene, or the like.

Meanwhile, the chemical imidization or thermal imidization process is performed under a basic catalyst such as pyridine, isoquinoline, trimethylamine, triethylamine, N-dimethylaminopyridine, imidazole, 1-methylpiperidine or 1-methylpiperazine. Here, the basic catalyst is used in a content of 0.1 to 5mol with respect to 1mol of the above acid dianhydride.

Using such imidization process, H of-CO-NH-and OH of-CO-OH in the polyamic acid molecule are dehydrated to prepare polyimide (-CO-N-CO-) having a cyclic chemical structure.

< separation and drying >

The prepared polyimide was separated from the polymerization solvent and dried to be used. The separation process is carried out by: to the thus obtained solution, a solvent poor for polyimide, such as methanol or isopropyl ether, is added to precipitate the polyimide, and then processes such as filtration, washing and drying are used. Thereafter, as the redissolving solvent, a solvent such as an organic solvent used in the polymerization reaction can be used.

< molecular weight >

The polyimide prepared as above has a number average molecular weight of 500g/mol to 80,000 g/mol. Furthermore, the functional group-modified polyimide has a number average molecular weight of 500g/mol to 80,000g/mol, preferably 500g/mol to 50,000g/mol or 500g/mol to 30,000 g/mol. Further, the ratio of the weight average molecular weight to the number average molecular weight (Mw/Mn) is greater than or equal to 1 and less than or equal to 3, preferably greater than or equal to 1 and less than or equal to 2.

When the number average molecular weight of the polyimide and the modified polyimide is 500 or more, the prepared film has improved mechanical characteristics, while when the number average molecular weight is 80,000 or less, good fluidity and the effect of allowing the ease of the preparation process of uniform coating during coating are obtained.

When the polyimide includes a relatively low molecular weight oligomer form, many reaction points capable of reacting with the curable reactive groups can be secured, and in addition, since the transmittance is increased due to the low molecular weight, an effect of reducing the Yellowness Index (YI) phenomenon is obtained.

< repeating Unit >

According to one embodiment of the present disclosure, the polyimide comprising the repeating unit of chemical formula 1 may be prepared by: the polyimide prepared by the separation and drying is dissolved in a solvent, and then the resultant is reacted with the curable functional group-containing compound represented by chemical formula 2 at a temperature of room temperature to 80 ℃ for 5 hours to 30 hours, preferably 10 hours to 30 hours. When the reaction temperature and the reaction time are within the above ranges, gelation of the polyimide solution is significantly suppressed, and the coating solution can be uniformly applied.

< solvent >

As the solvent used in the reaction of the polyimide and the compound of chemical formula 2, all solvents may be used as long as they dissolve the polyimide according to one embodiment of the present disclosure. Examples of the solvent may include aprotic solvents such as N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), γ -butyrolactone (GBL), Dimethylformamide (DMF), Diethylformamide (DEF), dimethylacetamide (DMAc), diethylacetamide (DEAc), Tetrahydrofuran (THF), or 2-butylcellosolve; or m-cresol, phenol, halophenol; and so on.

Further, the polyimide and the compound of chemical formula 2 are reacted in a ratio of 1:2 to 1:8, preferably 1:2 to 1: 6.

< curing >

The prepared modified polyimide is mixed with a photopolymerization initiator or a thermal polymerization initiator and a solvent to prepare the curable resin composition of the present disclosure.

Solvents

The solvent is not particularly limited as long as it uniformly dissolves the components and is chemically stable and thus non-reactive with the components of the composition. Examples of the solvent may include aprotic solvents such as N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), γ -butyrolactone (GBL), Dimethylformamide (DMF), Diethylformamide (DEF), dimethylacetamide (DMAc), diethylacetamide (DEAc), Tetrahydrofuran (THF), or 2-butylcellosolve; or m-cresol, phenol, halophenol; and so on.

Photopolymerization initiator

The photopolymerization initiator functions, for example, to initiate radical photocuring in the exposed portions of the resin composition. As the photopolymerization initiator, those known in the art may be used, and: materials formed from benzoin and its alkyl ethers (e.g., benzoin methyl ether or benzoin ethyl ether), such as benzoin-based compounds; acetophenone-based compounds, such as acetophenone, 2-dimethoxy-2-phenylacetophenone, 1-dichloroacetophenone or 4- (1-tert-butyldioxy-1-methylethyl) acetophenone; anthraquinone-based compounds such as 2-methylanthraquinone, 2-amylanthraquinone, 2-tert-butylanthraquinone or 1-chloroanthraquinone; thioxanthone compounds, such as 2, 4-dimethylthioxanthone, 2, 4-diisopropylthioxanthone or 2-chlorothioxanthone; ketal compounds, such as acetophenone dimethyl ketal or benzyl dimethyl ketal; and benzophenone-based compounds such as benzophenone, 4- (1-tert-butyldioxy-1-methylethyl) benzophenone or 3,3',4,4' -tetrakis (tert-butyldioxycarbonyl) benzophenone.

In addition, the following can also be used as stable photoinitiators: α -aminoacetophenone compounds such as 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropanone-1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholinyl) phenyl ] -1-butanone, N-dimethylaminoacetophenone (as a commercially available product, Irgacure (registered trademark) 907, Irgacure 369, Irgacure 379 and the like manufactured by Ciba Specialty Chemicals Inc (currently Ciba Japan)); and acylphosphine oxide compounds such as 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide, bis (2, 6-dimethoxybenzoyl) -2,4, 4-trimethyl-pentylphosphine oxide (as a commercially available product, Lucirin (registered trademark) TPO manufactured by BASF Corporation, Irgacure 819 manufactured by Ciba Specialty Chemicals inc., and the like). Examples of additional suitable photoinitiators may include oxime ester compounds. Specific examples of the oxime ester compound may include 2- (acetyloxyiminomethyl) thioxanthen-9-one, (1, 2-octanedione, 1- [4- (phenylthio) phenyl ] -,2- (O-benzoyloxime)), (ethanone, 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -,1- (O-acetyloxime)), and the like. As commercially available products, GGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by Ciba Specialty Chemicals Inc.; n-1919 manufactured by ADEKA Corporation; darocur TPO manufactured by Ciba Specialty Chemicals Inc.; and so on. Further, a bisimidazole-based compound, a triazine-based compound, or the like may also be used as a suitable photoinitiator.

The photopolymerization initiator may be contained in an amount of 0.5 to 20 wt%, 1 to 10 wt%, or 1 to 5 wt% relative to the total weight of the resin composition. When the photoinitiator content is within the above range, photocuring can be performed well.

Thermal polymerization initiator

As the thermal polymerization initiator, those generally called radical polymerization initiators can be used. For example, azo compounds such as 2,2' -azobisisobutyronitrile, 2' -azobis- (2, 4-dimethylvaleronitrile) or 2,2' -azobis- (4-methoxy-2, 4-dimethylvaleronitrile); organic peroxides, such as benzoyl peroxide, t-butyl peroxypivalate, or 1,1' -bis- (t-butylperoxy) cyclohexane; and hydrogen peroxide. When a peroxide is used as the radical polymerization initiator, the peroxide may be used together with a reducing agent to serve as a redox initiator. Preferably, azo compounds may be used.

The content of the thermal polymerization initiator is 0.5 to 20 wt%, 1 to 15 wt%, or 5 to 10 wt% with respect to the total weight of the resin composition. When the photoinitiator content is within the above range, photocuring can be sufficiently performed.

Polymerizable Compound

According to one embodiment, the curable resin composition further comprises a urethane (meth) acrylate-based compound and/or a polymerizable compound having an ethylenically unsaturated bond.

The polymerizable compound having an ethylenically unsaturated bond can improve the heat resistance and surface hardness of a polyimide protective film obtained later.

The polymerizable compound having an ethylenically unsaturated bond is selected from monofunctional, bifunctional or trifunctional or higher-functional (meth) acrylates, and the monofunctional (meth) acrylate may be selected from, for example, 2-hydroxyethyl (meth) acrylate, carbitol (meth) acrylate, isobornyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, and the like.

The difunctional (meth) acrylate may be selected from, for example, ethylene glycol (meth) acrylate, 1, 6-hexanediol (meth) acrylate, 1, 9-nonanediol (meth) acrylate, propylene glycol (meth) acrylate, tetraethylene glycol (meth) acrylate, bisphenoxyethanolfluorene diacrylate, and the like.

The trifunctional or higher-functional (meth) acrylate may be selected from, for example, trishydroxyethyl isocyanurate tri (meth) acrylate, trimethylpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

Alternatively, one type selected from monofunctional, bifunctional, or trifunctional or higher-functional (meth) acrylates may be used alone or as a combination of two or more types.

The polymerizable compound is contained in an amount of 20 to 100 parts by weight or 20 to 70 parts by weight, preferably 20 to 50 parts by weight, relative to 100 parts by weight of the modified polyimide of chemical formula 4. When the polymerizable compound content is 20 parts by weight or more relative to 100 parts by weight of the modified polyimide, the degree of curing can be improved, and when the content is 100 parts by weight or less, the adhesiveness of the obtained coating film can be improved.

The urethane (meth) acrylate-based compound is selected from, for example, a hydroxy (meth) acrylate compound such as hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate or tetramethylolethane tri (meth) acrylate; urethane (meth) acrylates containing allophanate-modified polyisocyanurates; and urethane (meth) acrylates containing allophanate-modified polyisocyanurates.

The urethane (meth) acrylate-based compound is included in an amount of 20 to 100 parts by weight or 30 to 80 parts by weight, preferably 40 to 60 parts by weight, relative to 100 parts by weight of the modified polyimide of chemical formula 4. When the polymerizable compound content is 20 parts by weight or more relative to 100 parts by weight of the modified polyimide, the degree of curing can be improved, and when the content is 100 parts by weight or less, the adhesiveness of the obtained coating film can be improved.

According to one embodiment, the weight average molecular weight of the urethane resin is 1,000 to 20,000, and when the weight average molecular weight of the urethane resin is within the above range, the efficiency of processability can be improved by adjusting the viscosity.

Further, as other additives, the present disclosure may further include one or more types selected from a surfactant, an adhesion promoter, a thermal radical polymerization initiator, and an antioxidant.

[ hollow particles ]

The present disclosure uses hollow particles. The outer layer of the hollow particles may be an inorganic material or an organic material. For example, inorganic materials formed of metal, metal oxide, resin, silica, aluminum oxide, titanium oxide, zinc oxide particles, or the like may be preferably included, and in particular, hollow silica particles having a silica outer layer are preferable.

When the outer layer is silica, the corresponding silica may be in any state of crystalline, sol-phase and gel-phase. The shape of the hollow particles may be any of true spheres, nearly spheres (e.g., ellipsoids and polyhedral shapes that may be more nearly spherical), polyhedral shapes, chains, needles, plates, chips, rods, fibers, and the like. Among them, true spherical, approximately spherical and polyhedral shapes are preferable, and ellipsoidal, true spherical or cubic shapes are particularly preferable.

With respect to the particle size of the hollow particles, the average particle diameter (d50 median diameter), defined as 50% of the particle size when the particle size distribution measured using a dynamic light scattering method is expressed as a volume cumulative distribution (hereinafter, sometimes simply referred to as "average particle diameter (d 50)"), is greater than or equal to 10nm and less than or equal to 300nm, preferably greater than or equal to 30nm and less than or equal to 200nm, and particularly preferably greater than or equal to 40nm and less than or equal to 150 nm.

When the average particle diameter (d50) of the hollow particles is within the corresponding range, excellent transparency can be ensured. In other words, when the lower limit value of the average particle diameter (d50) of the hollow particles is 10nm or more, since the volume of the hollow portion with respect to the thickness of the outer layer increases, the porosity increases, and when the upper limit value is 300nm or less, the visibility of the particles may decrease (the transparency increases), which may improve the transmittance of the substrate.

The average particle diameter (d50) can be measured according to the Dynamic Light Scattering (DLS) method using, for example, a Microtrac particle size analyzer or a Nanotrac particle size analyzer manufactured by Nikkiso co.

As such hollow silica particles, suitable materials can be selected from commercially available products. Examples of specific products may include SiliNax (cubic, average primary particle diameter 80nm to 130nm) manufactured by nitttsu Mining co., ltd and as a product of dispersing hollow silica particles into a solvent; thruya 1110 (spherical, average primary particle diameter 50nm), thruya 2320 (spherical, average primary particle diameter 50nm), thruya 4110 (spherical, average primary particle diameter 60nm), thruya 4320 (spherical, average primary particle diameter 60nm) manufactured by Nikki Chemical co., ltd.; and hollow silica (spherical, average primary particle diameter 80nm to 150nm) manufactured by Fuso Chemical co., ltd.; and so on.

Further, as the hollow particles (particularly, silica), particles whose surfaces are treated with a fluorine-based compound may be mixed thereto and used. In other words, when the hollow particles are surface-treated with the fluorine-based compound, the particle surface energy can be further reduced, which makes the distribution in the composition more uniform, and thus, a more uniform scratch resistance-improving effect can be induced. As a method of introducing the fluorine-based compound to the surface of the hollow silica particles, a method of hydrolyzing and condensing the hollow particles and the fluorine-based compound using a sol-gel reaction in the presence of water and a catalyst may be performed. Further, as the hollow particles, those dispersed in an organic solvent may be used, and the content of the solid (hollow particles) in the dispersion liquid may be determined in consideration of the above-described hollow particle content range and viscosity range suitable for coating of the composition.

In the present disclosure, when hollow silica particles are used as the hollow particles, the refractive index of the polyimide-based resin after curing at a wavelength of 632.8nm is preferably greater than or equal to 1.40 and less than or equal to 1.55. When the refractive index of the polyimide-based resin after curing is within the above range, the difference in refractive index from the hollow silica particles decreases, and when the hollow silica particles are dispersed, the occurrence of haze is suppressed, and thus, the transmittance of the base material may be increased.

< dispersant >

According to an aspect of the present disclosure, a polyether-modified silicone oil may also be included as a dispersant. By further containing the polyether-modified silicone oil, the dispersibility of the hollow particles can be improved.

The polyether-modified silicone oil is a silicone-based polymer surfactant that introduces a hydrophilic polyoxyalkylene into a hydrophobic dimethylsilicone and has a number average molecular weight of, for example, 1,000 to 100,000, preferably 2,000 to 50,000. The polyether-modified silicone oil may be included at about 0.001 wt% to 1 wt% with respect to the total weight (100 wt%) of the heat-resistant substrate for an electronic device.

Examples of specific products may include L-45, L-9300, FZ-3704, FZ-3703, FZ-3720, FZ-3786, FZ-3501, FZ-3504, FZ-3508, FZ-3705, FZ-3707, FZ-3710, FZ-3750, FZ-3760, FZ-3785, and Y-7499 manufactured by Nippon Unicar Co., Ltd.; and KF96L, KF96, KF96H, KF99, KF54, KF965, KF968, KF56, KF995, KF351, KF352, KF353, KF354, KF355, KF615, KF618, KF945, KF6004, and FL100, manufactured by Shin-Etsu Chemical co. And so on.

< surfactant >

According to an aspect of the present disclosure, as the surfactant, the surfactant may further include a monofunctional to bifunctional fluorine-based acrylate or fluorine-based surfactant. By using the fluorine-based surfactant, uniform dispersion of the hollow particles can be achieved.

As such a fluorine-based surfactant, those commonly used in the art may be used, and the composition thereof is not particularly limited. However, according to one embodiment of the present disclosure, commercially available products of fluorine-based surfactants include magace F-444, magace F-445, magace F-470, magace F-477, magace MCF-350SF, etc. from DIC Corporation.

The fluorine-based surfactant may be included at about 0.001 wt% to 1 wt% with respect to the total weight (100 wt%) of the heat-resistant substrate for an electronic device.

< content >

The hollow particles are contained in more than 10% by weight and less than 80% by weight, preferably in more than 20% by weight and less than 70% by weight, and more preferably in more than 30% by weight and less than 60% by weight, relative to the total weight (100% by weight) of the heat-resistant substrate for electronic devices. When the amount of the hollow particles is more than 10% by weight with respect to the total weight, the transparency at a high temperature of 320 ℃ or more can be improved, and when the amount is less than 80% by weight, the mechanical strength such as flexibility or bending resistance of the substrate can be improved.

[ method for producing Heat-resistant base Material for electronic device ]

(adjustment of liquid composition)

In the heat-resistant base material for electronic devices, a polyimide-based resin, hollow particles, and, as necessary, a dispersant, a surfactant, a photoinitiator, a polymerization initiator, a solvent, and the like are mixed and stirred to adjust a liquid composition. Mixing and stirring can be performed using a common stirrer and mixer.

As the solvent, those commonly used in the art may be used within a range that does not affect the characteristics of the composition. The solvent may be of one or more types selected from: ketones, alcohols, acetates and ethers, more specifically, ketones including methyl ethyl ketone, methyl isobutyl ketone, acetylacetone and isobutyl ketone; alcohols including methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and tert-butanol; acetates, including ethyl acetate, isopropyl acetate and polyethylene glycol monomethyl ether acetate; ethers, including tetrahydrofuran and propylene glycol monomethyl ether; aprotic solvents such as N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), γ -butyrolactone (GBL), Dimethylformamide (DMF), Diethylformamide (DEF), dimethylacetamide (DMAc), diethylacetamide (DEAc), Tetrahydrofuran (THF) or 2-butylcellosolve; or m-cresol, phenol, halophenol; or mixtures thereof.

The solvent may be added in the form of a dispersion liquid in which the hollow particles are dispersed. The solvent content may be appropriately determined, but may include: so that the concentration of solids contained in the heat-resistant base material for electronic devices becomes 1 to 60 wt%, and more preferably 3 to 50 wt%.

(preparation of the substrate)

The liquid composition adjusted above was coated on a substrate (easy to peel) and cured.

As the coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a micro-gravure coating method, a comma coating method, a slit die coating method, a lip coating method, a solution casting method, or the like can be used.

As for the polymerization method, various methods such as ultraviolet irradiation, radical polymerization, and polymerization by heating may be used to perform the objective curing.

(peeling)

The cured polymer structure (film, etc.) is peeled off (easily peeled) from the substrate, and molding is performed to obtain a heat-resistant base material for electronic devices.

[ Properties ]

The heat resistant substrate for electronic devices preferably has a light transmittance of 85% or more measured using a spectrophotometer and may have a haze of 1.0% or less, 0.5% or less, or 0.4% or less. The measurement can be performed using a transmissometer, a haze meter, or the like according to, for example, JIS Z8722, JIS K7361-1, JIS K7136, and JIS K7105.

Further, the Yellowness Index (YI) value of the heat-resistant substrate for electronic devices may be measured using a spectrophotometer according to JIS K7373 and JIS-Z8729. The determination criterion of YI also depends on the use or thickness of the substrate, however, as a value at which the yellow color caused by visual appearance is not disturbed when used as a heat-resistant substrate for electronic devices (for example, thickness of 20 μm), the YI value is preferably 5.0 or less, particularly preferably 3.0 or less. When the upper limit value of YI is 5.0 or less, the substrate may be suitably used as an optical film for a display requiring high visibility.

The heat resistant substrate for an electronic device may have an initial color b (CIE 1976L a b in color space) of 1.0 or less. Further, the difference between the initial color b and the color b after 72 hours or more of exposure to the uv lamps in the UVB wavelength region may be 0.5 or less, or 0.4 or less.

The thickness of the heat-resistant substrate for electronic devices is greater than or equal to 5 μm and less than or equal to 400 μm, preferably greater than or equal to 10 μm and less than or equal to 150 μm. The hardness of the heat-resistant base material for electronic devices may be, for example, 6H or more, 7H or more, or 8H or more pencil hardness (JIS K5600) under a load of 1 kg.

[ application ]

A heat-resistant substrate for electronic devices can replace a glass substrate because it has transparency, heat resistance and mechanical strength, and is also improved in excellent optical characteristics and quality. Specifically, the heat-resistant substrate for electronic devices can be used as the substrate itself of a basic structure used in electronic devices (optical substrates, electronic components, devices). Therefore, the heat-resistant substrate for electronic devices is used as a substrate for supporting basic structures in electronic devices, such as displays, lenses, Thin Film Transistors (TFTs), polarizing plates, alignment films, color filters, optical compensation films, antireflection films, antiglare films, surface treatment films, antistatic films, spacers, capacitors, vibration elements, or actuators.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

[ examples ]

Hereinafter, the present disclosure will be described in detail by describing operations and effects thereof through the following specific embodiments. The respective embodiments form one example of the present disclosure, and technical ideas covered by the scope of the present disclosure can be easily implemented by the respective embodiments. Meanwhile, the embodiment presents only one aspect of the present disclosure, and the scope of rights of the present disclosure is not limited and specified by the existence of the corresponding embodiment.

[ example 1]

< preparation of modified polyimide resin A1 >

After 2,2' -bis (trifluoromethyl) -4,4' -diaminobiphenyl (TFMB) (1mol) was dissolved in DEF (80g), 4' -oxydiphthalic anhydride (ODPA) (1.1mol) was added thereto, and the mixture was introduced into N, N-Diethylformamide (DEF) (50 g). The resultant was polymerized at 50 ℃ for 24 hours to obtain a solution containing polyamic acid.

Toluene (40g) was introduced into the solution, and after a Dean-Stark distillation apparatus was installed to remove water, the resultant was refluxed at 180 ℃ for 12 hours to obtain a polyimide solution. In the polyimide solution, a precipitate was produced using a methanol solvent, followed by drying, and after the dried polyimide was dissolved in DEF (50g), 2-methacryloyloxyethyl isocyanate (MOI) (3 moles) was added thereto, followed by introducing DEF (30g) thereto, and the resultant was reacted at room temperature for 24 hours. A precipitate was generated using methanol, and then dried to obtain a modified polyimide resin a 1.

< preparation of Heat-curable coating composition a 1>

To a modified polyimide resin a1(10g), urethane acrylic oligomer (acryl oligomer) SP260 (manufactured by Soltech ltd.) (5g) was introduced, and after dipentaerythritol hexaacrylate (DPHA) (4g) was introduced thereto, DEF was introduced into a thermal initiator (2,2' -azobis (2, 4-dimethylvaleronitrile), V65 (manufactured by Wako Pure Chemical Industries ltd.) (1g) for 10 hours with a half-life temperature of 50 ℃) so that the solid content became 30% by weight, and the resultant was mixed to obtain a heat-curable coating composition a 1.

< preparation of hollow particle silica particle-dispersed liquid b 1>

The surface of the hollow silica particles B1 having an average primary particle diameter of 80nm was treated with a fluorine-based compound using a sol-gel reaction to obtain 20% by weight of the hollow silica particle dispersion liquid B1 in methyl isobutyl ketone (MIBK).

< preparation of base Material >

The heat-curable coating composition a1 and the hollow silica particle dispersion liquid b1 were mixed so that the weight ratio of solids of the heat-curable coating composition a1 and the hollow silica particle dispersion liquid b1 was 70:30, and stirred to obtain a composition. The composition was coated on a glass substrate coated with a release agent using spin coating. Thereafter, the resultant was dried in an oven at 100 ℃ for 10 minutes under a nitrogen atmosphere, and heat-treated for 30 minutes after raising the temperature to 350 ℃ at a temperature raising rate of 5 ℃/minute. After being taken out of the oven, the resultant was peeled off from the glass substrate to obtain a single-layer polymer film substrate having a thickness of 20 μm.

[ example 2]

< preparation of Heat-curable coating composition a 2>

To a modified polyimide resin a1(10g), a urethane acrylic oligomer SU5260 (manufactured by Soltech ltd.) (5g) was introduced, and after dipentaerythritol hexaacrylate (DPHA) (4g) was introduced thereto, DEF was introduced into a thermal initiator (2,2' -azobis (2, 4-dimethylvaleronitrile), V65 (manufactured by Wako Pure Chemical Industries ltd.), 10 hours, half-life temperature 50 ℃) (1g) so that the solid content became 30% by weight, and the resultant was mixed to obtain a heat-curable coating composition a 2.

< preparation of base Material >

The heat-curable coating composition a2 and the hollow silica particle dispersion liquid b1 were mixed so that the weight ratio of solids of the heat-curable coating composition a2 and the hollow silica particle dispersion liquid b1 was 60:40, and stirred to obtain a composition. Using this composition, a single-layer polymer film substrate having a thickness of 20 μm was prepared in the same manner as in example 1.

Comparative example 1

A single-layer polymer film substrate having a thickness of 20 μm was prepared in the same manner as in example 1, except that the curable coating composition was coated only on the glass substrate without mixing the hollow silica particles.

Comparative example 2

A single-layer polymer film substrate having a thickness of 20 μm was prepared in the same manner as in example 2, except that the curable coating composition was coated only on the glass substrate without mixing the hollow silica particles.

[ evaluation test: evaluation test of optical Properties

For each of the polymer film substrates obtained in examples 1 and 2 and comparative examples 1 and 2, the optical characteristics of the film, such as transmittance and yellowness index, were measured using the following methods.

The transmittance was measured using a spectrophotometer (manufactured by JASCO, model V-770). In addition, the yellowness index ("YI") is measured by installing an integrating sphere unit in a spectrophotometer and using the color evaluation (color diagnosis) program VWCD-960. These results are shown in table 1.

[ results ]

As described below [ table 1], in example 1 and comparative example 1 and in example 2 and comparative example 2 having the same substrate thickness, the transmittance (at 550 nm) (%) and the transmittance (at 460 nm) (%) were excellent in example 1 in terms of transparency, and it is understood that, with respect to "YI", examples 1 and 2 clearly had lower coloring degrees than comparative examples 1 and 2.

[ Table 1]