KR102475748B1 - An optical member comprising a polyamideimide resin and the polyamideimide resin - Google Patents

Abstract

A polyamideimide resin for an optical member having both high flexibility and bending resistance, particularly a polyamideimide resin for a front plate of an image display device, and an optical member such as a front plate containing the polyamideimide resin are provided. Polyamide-imide resin which has structural units represented by following formula (1) and following formula (2); [In Formula (1) and Formula (2), X and Z each independently represent a divalent organic group, Y represents a tetravalent organic group, and at least a part of Z is Formula (3): (Formula (3) ), R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atom contained in R ¹ to R ⁸ is each independently a halogen atom. may be substituted with an atom, A represents -O-, -S-, -CO- or -NR ⁹ -, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom, and m is 1 to 12 It is an integer of 4, and * represents a bond) is a constituent unit represented by].

Description

An optical member comprising a polyamideimide resin and the polyamideimide resin

The present invention relates to a polyamide-imide resin and an optical member comprising the polyamide-imide resin.

Currently, image display devices such as liquid crystal display devices and organic EL display devices are widely used not only for televisions but also for various applications such as mobile phones and smart watches. Along with the expansion of these uses, an image display device (flexible display) having flexible characteristics is in demand.

BACKGROUND ART An image display device is composed of display elements such as a liquid crystal display element or an organic EL display element, as well as structural members such as a polarizing plate, a retardation plate, and a front plate. In order to achieve a flexible display, all of these constituent members need to have flexibility.

Until now, glass has been used as the front plate. While glass has high transparency and can exhibit high hardness depending on the type of glass, it is very rigid and brittle, so it is difficult to use it as a front plate material for flexible displays.

For this reason, utilization of a polymeric material as a material in place of glass is being studied. Since the front plate made of a polymer material tends to exhibit flexible characteristics, it can be expected to be used for various purposes. A variety of resins having flexibility can be cited, but polyamideimide resin is one of them. Polyamide-imide resins are used in various applications from the viewpoint of transparency and heat resistance (Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-150552

When the flexible display is bent, all constituent members are bent. If the flexibility of each constituent member is insufficient, other constituent members may be damaged. For this reason, high flexibility is also required for the front plate, which is one of the constituent members. At the same time, the front plate needs to have high resistance to bending, since a problem in the visibility of the display will occur if creases remain on the surface after the front plate is bent.

Therefore, the present invention is a polyamide-imide resin for an optical member having both high flexibility and bending resistance, particularly a polyamide-imide resin for a front plate of an image display device, and a front plate comprising the polyamide-imide resin. It aims to provide members.

The present inventors came to complete this invention, as a result of earnestly examining in order to solve the said subject.

That is, the present invention provides the following preferred aspects.

[1] Equation (1) and Equation (2):

[In Formula (1) and Formula (2), X and Z each independently represent a divalent organic group,

Y represents a tetravalent organic group,

At least part of Z is Equation (3):

[In Formula (3), R ¹ to ^{R 8} each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹ to R ⁸ are each Independently, it may be substituted with a halogen atom,

A represents -O-, -S-, -CO- or NR ⁹ -, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,

m is an integer from 1 to 4;

* represents a binding hand]

It is a constituent unit represented by]

A polyamideimide resin having a structural unit represented by

[2] The polyamideimide resin according to [1] above, wherein the content of the structural unit represented by formula (3) is 3 mol% or more and 90 mol% or less with respect to the total of Y and Z.

[3] The polyamideimide resin described in [1] above, wherein 5 mol% or more and 100 mol% or less of Z are represented by formula (3).

[4] The above [1] in which the ratio of the structural unit represented by formula (3) to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2) is 3 mol% or more and 90 mol% or less. The polyamideimide resin described in.

[5] The content rate of the structural unit represented by formula (1) is 10 mol% or more and 90 mol% or less with respect to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2), the above [1] The polyamide-imide resin described in any of [4].

[6] At least part of X is expressed in equation (4):

[In Formula (4), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁰ to R ¹⁷ are each Independently, it may be substituted with a halogen atom,

* represents a bonding hand]

The polyamideimide resin according to any one of [1] to [5] above, which is a structural unit represented by

[7] At least part of Y is Equation (5):

[In Formula (5), R ¹⁸ to R ²⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁸ to R ²⁵ are each Independently, it may be substituted with a halogen atom,

* represents a bonding hand]

The polyamideimide resin according to any one of [1] to [6] above, which is a structural unit represented by

[8] The polyamideimide resin according to any one of [1] to [7] above, wherein the glass transition temperature Tg calculated by tan δ in DMA measurement is less than 380°C.

[9] An optical member comprising the polyamideimide resin according to any one of [1] to [8] above.

[10] An image display device provided with the optical member described in [9] above.

According to the present invention, a polyamide-imide resin for an optical member having both high flexibility and bending resistance, particularly a polyamide-imide resin for a front plate of an image display device, and a front plate containing the polyamide-imide resin are used for optics. member can be provided. In addition, according to the present invention, an optical member having excellent surface hardness can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. In addition, the scope of the present invention is not limited to the embodiments described here, and various changes can be made within a range not impairing the gist of the present invention.

The polyamide-imide resin, which is an embodiment of the present invention, has a structural unit represented by Formula (1) and a structural unit represented by Formula (2).

In Formula (2), Z each independently represents a divalent organic group. The polyamide-imide resin, which is an embodiment of the present invention, may contain plural types of Z, and the plural types of Z may be the same as or different from each other. At least one part of Z is a structural unit represented by Formula (3).

[In Formula (3), R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atom contained in R ¹ to R ⁸ is each Independently, it may be substituted with a halogen atom,

A represents -O-, -S-, -CO- or NR ⁹ -, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,

m is an integer from 1 to 4;

* represents a binding hand.]

In Formula (3), A each independently represents -O-, -S-, -CO- or NR ⁹ -, and from the viewpoint of flexibility of the optical member made of the polyamideimide resin, it is preferable Preferably -O- or S-, more preferably -O-. R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and from the viewpoint of flexibility and surface hardness of an optical member made of the polyamideimide resin, Preferably, it represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and still more preferably represents a hydrogen atom. Here, the hydrogen atoms contained in R ¹ to R ⁸ may each independently be substituted with a halogen atom. R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom.

In formula (3), m is an integer in the range of 1 to 4, and when m is within this range, the flexibility of the optical member is good. In formula (3), m is preferably an integer in the range of 1 to 3, more preferably 1 or 2, still more preferably 1, and when m is within this range, the flexibility of the optical member increases. While being good, the availability of raw materials is relatively good.

In a preferred embodiment of the present invention, formula (3) is a structural unit represented by formula (3'), that is, at least a part of a plurality of Z is a structural unit represented by formula (3'). In this case, the optical member made of the polyamide-imide resin exhibits high surface hardness, has a low modulus of elasticity, and can have high flexibility.

In a preferred embodiment of the present invention, the content of the structural unit represented by formula (3) with respect to the total of Y and Z in the polyamideimide resin is preferably 3 mol% or more, more preferably 5 mol% or more, more preferably 7 mol% or more, even more preferably 9 mol% or more, particularly preferably 15 mol% or more, very preferably 30 mol% or more, preferably 90 mol% or less, more preferably It is preferably 87 mol% or less, more preferably 85 mol% or less, particularly preferably 83 mol% or less, and very preferably 80 mol% or less. When the content of the structural unit represented by formula (3) with respect to the sum of Y and Z in the polyamideimide resin is equal to or greater than the lower limit, the optical member made of the polyamideimide resin has a low modulus of elasticity and excellent flexibility, At the same time, high surface hardness can be expressed. When the content of the structural unit represented by formula (3) with respect to the total of Y and Z in the polyamideimide resin is equal to or less than the above upper limit, by suppressing the thickening due to hydrogen bonds between amide bonds derived from formula (3), the polyamide-imide resin described later The viscosity of the amide-imide varnish can be suppressed, and processing of optical members can be facilitated. In addition, the content rate of the structural unit represented by Formula (3) can be measured using ¹ H-NMR, for example, or it can also be calculated from the introduction ratio of raw materials.

In a preferred embodiment of the present invention, Z in the polyamideimide resin is preferably 5 mol% or more, more preferably 7 mol% or more, still more preferably 9 mol% or more, particularly preferably 11 mol% % or more is represented by formula (3). When the above lower limit value or more of Z in the polyamideimide resin is represented by formula (3), the optical member made of the polyamideimide resin exhibits high surface hardness, has a low elastic modulus, and can have high flexibility. . Moreover, it is preferable that 100 mol% or less of Z in the said polyamideimide resin is represented by Formula (3). In addition, the content rate of the structural unit represented by Formula (3) in the said polyamideimide resin can be measured using ^<1> H-NMR, for example, or it can also be computed from the introduction ratio of a raw material.

In a preferred embodiment of the present invention, the ratio of the structural unit represented by formula (3) to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2) in the polyamideimide resin is preferably Preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 7 mol% or more, even more preferably 9 mol% or more, particularly preferably 15 mol% or more, very preferably 30 mol% % or more, preferably 90 mol% or less, more preferably 87 mol% or less, still more preferably 85 mol% or less, particularly preferably 83 mol% or less, and very preferably 80 mol% or less. When the ratio of the structural unit represented by formula (3) to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2) in the polyamideimide resin is equal to or greater than the lower limit, the polyamideimide resin is included. The optical member made of the above has a low modulus of elasticity, excellent flexibility, and at the same time can express high surface hardness. If the ratio of the structural unit represented by formula (3) to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2) in the polyamideimide resin is equal to or less than the above upper limit, the amide derived from formula (3) By suppressing the thickening by the hydrogen bond between bonds, the viscosity of the polyamide-imide varnish described later can be suppressed, and processing of the optical member can be facilitated. In addition, the content rate of the structural unit represented by Formula (3) can be measured using ¹ H-NMR, for example, or it can also be calculated from the introduction ratio of raw materials.

In Formulas (1) and (2), X each independently represents a divalent organic group, and is preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. In addition, X in Formula (1) may be the same as or different from X in Formula (2). The polyamide-imide resin, which is an embodiment of the present invention, may contain multiple types of X, and the multiple types of X may be the same as or different from each other. As X, the following formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) or formula (18) appear; groups in which hydrogen atoms in groups represented by these formulas are substituted with methyl, fluoro, chloro or trifluoromethyl groups; and a chain hydrocarbon group having 6 or less carbon atoms.

[In Formula (10), Formula (11), Formula (12), Formula (13), Formula (14), Formula (15), Formula (16), Formula (17), or Formula (18), * is a bond represent hands,

V ¹ to V ³ are each independently a single bond, -O-, -S-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or CO-.]

The bonding position to each ring of V ¹ and V ² and the bonding position to each ring of V ² and V ³ are preferably meta-position or para-position, respectively, and para-position with respect to each ring. more preferable

Among the groups represented by formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) or formula (18), the From the viewpoint of surface hardness and flexibility of an optical member made of polyamideimide resin, a group represented by formula (13), formula (14), formula (15), formula (16) or formula (17) is preferable, and The group represented by (14), formula (15) or formula (16) is more preferable. From the viewpoint of the surface hardness and flexibility of the optical member made of the polyamideimide resin, V ¹ to V ³ are each independently preferably a single bond, -O-, or S-, and a single bond or It is more preferably O-.

In a preferred embodiment of the present invention, at least one part of a plurality of Xs in formulas (1) and (2) is a structural unit represented by formula (4). When at least a part of the plurality of Xs in formulas (1) and (2) is a group represented by formula (4), the optical member made of the polyamideimide resin expresses high transparency and has high surface hardness. can express.

[In Formula (4), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁰ to R ¹⁷ are each Independently, it may be substituted with a halogen atom,

* represents a binding hand.]

In Formula (4), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms more preferably, wherein the hydrogen atoms contained in R ¹⁰ to R ¹⁷ may each independently be substituted with a halogen atom. R ¹⁰ to R ¹⁷ are each independently a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a triglyceride group, more preferably from the viewpoint of the surface hardness, flexibility and transparency of the optical member comprising the polyamideimide resin. It is a fluoromethyl group, and a hydrogen atom or a trifluoromethyl group is particularly preferred.

In a preferred embodiment of the present invention, the structural unit represented by formula (4) is a structural unit represented by formula (4'), that is, at least a part of the plurality of X's is a structural unit represented by formula (4'). In this case, the optical member made of the polyamide-imide resin exhibits high transparency, and at the same time, the solubility of the polyamide-imide resin in a solvent is improved by the fluorine element-containing skeleton, thereby forming a polyamide-imide varnish. The viscosity of can be suppressed low, and processing of an optical member can be made easy.

[In formula (4'), * represents a bond]

In a preferred embodiment of the present invention, preferably 30 mol% or more, more preferably 50 mol% or more, still more preferably 60 mol% or more, particularly preferably 70 mol% of X in the polyamideimide resin % or more is represented by formula (4), particularly formula (4'). When X within the above range in the polyamideimide resin is represented by formula (4), particularly formula (4'), an optical member made of the polyamideimide resin exhibits high transparency and element fluorine. The solubility of the polyamide-imide resin in a solvent is improved by the skeleton containing , the viscosity of the polyamide-imide varnish can be kept low, and processing of optical members can be facilitated. Also preferably, 100 mol% or less of X in the polyamideimide resin is represented by formula (4), particularly formula (4'). Formula (4), especially Formula (4'), may be sufficient as X in the said polyamideimide resin. The content rate of the structural unit represented by formula (4) of X in the polyamideimide resin can be measured, for example, using ¹ H-NMR, or can be calculated from the introduction ratio of raw materials.

In Formula (1), Y each independently represents a tetravalent organic group, and is preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. The polyamide-imide resin, which is an embodiment of the present invention, may contain plural types of Y, and the plural types of Y may be the same as or different from each other. As Y, formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or formula ( 29); groups in which hydrogen atoms in groups represented by these formulas are substituted with methyl, fluoro, chloro or trifluoromethyl groups; and a tetravalent chain hydrocarbon group having 6 or less carbon atoms.

[In formula (20) to formula (29),

* represents a bonding hand,

W ¹ is a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -Ar-, -SO ₂ -, -CO-, -O-Ar-O-, -Ar-O-Ar-, -Ar-CH ₂ -Ar-, -Ar-C(CH ₃ ) ₂ -Ar- or Ar-SO ₂ -Ar-. Ar represents an arylene group having 6 to 20 carbon atoms in which hydrogen atoms may be substituted with fluorine atoms, and specific examples include phenylene groups.]

Equation (20), Equation (21), Equation (22), Equation (23), Equation (24), Equation (25), Equation (26), Equation (27), Equation (28) and Equation (29) Among the groups shown, from the viewpoint of the surface hardness and flexibility of the optical member comprising the polyamideimide resin, the group represented by formula (26), formula (28) or formula (29) is preferable, and represented by formula (26) Giga is more preferred. From the viewpoint of easy suppression of yellowness, preferably formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26) or formula (27) ) group represented by; and groups in which hydrogen atoms in these groups are substituted with methyl, fluoro, chloro or trifluoromethyl groups. In addition, W ¹ is each independently a single bond, -O-, -CH ₂ -, -CH ₂ -CH ₂ -, from the viewpoint of the surface hardness and flexibility of the optical member made of the polyamideimide resin. -CH(CH ₃ )-, -C(CH ₃ ) ₂ - or C(CF ₃ ) ₂ - is preferable, and a single bond, -O-, -CH ₂ -, -CH(CH ₃ )-, - It is more preferably C(CH ₃ ) ₂ - or C(CF ₃ ) ₂ -, more preferably a single bond, -O-, -C(CH ₃ ) ₂ - or C(CF ₃ ) ₂ -, -O- or C(CF ₃ ) ₂ - is particularly preferred.

In a preferred embodiment of the present invention, at least one part of a plurality of Ys in formula (1) is a structural unit represented by formula (5). When at least a part of the plurality of Ys in formula (1) is a group represented by formula (5), the optical member made of the polyamideimide resin expresses high transparency and is derived from a highly flexible skeleton, By improving the solubility of the polyamide-imide resin in a solvent, the viscosity of the polyamide-imide varnish can be kept low, and processing of optical members can be facilitated.

[In Formula (5), R ¹⁸ to R ²⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁸ to R ²⁵ are each Independently, it may be substituted with a halogen atom,

* represents a binding hand.]

In Formula (5), R ¹⁸ to R ²⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms more preferably, wherein the hydrogen atoms contained in R ¹⁸ to R ²⁵ may each independently be substituted with a halogen atom. R ¹⁸ to R ²⁵ are each independently a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoro group, more preferably from the viewpoint of the surface hardness and flexibility of the optical member comprising the polyamideimide resin. It is a methyl group, and it is a hydrogen atom or a trifluoromethyl group especially preferably.

In a preferred embodiment of the present invention, the structural unit represented by formula (5) is a group represented by formula (5'), that is, at least a part of the plurality of Y is a structural unit represented by formula (5'). In this case, the optical member made of the polyamideimide resin can have high transparency.

[In formula (5'), * represents a bond]

In a preferred embodiment of the present invention, preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more of Y in the polyamideimide resin is represented by the formula (5), particularly It is represented by formula (5'). When Y within the above range in the polyamideimide resin is represented by formula (5), particularly formula (5'), an optical member made of the polyamideimide resin can have high transparency, and further element fluorine. The solubility of the polyamide-imide resin in the solvent is improved by the skeleton containing the, the viscosity of the polyamide-imide varnish can be kept low, and the manufacture of the optical member is easy. Also preferably, 100 mol% or less of Y in the polyamideimide resin is represented by formula (5), particularly formula (5'). Y in the said polyamideimide resin may be Formula (5), especially Formula (5'). The content rate of the structural unit represented by formula (5) of Y in the polyamideimide resin can be measured, for example, using ¹ H-NMR, or can be calculated from the introduction ratio of raw materials.

The weight average molecular weight (Mw) of the polyamideimide resin is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 50,000 or more, particularly preferably 70,000 or more, particularly preferably 100,000 or more, It is preferably 800,000 or less, more preferably 600,000 or less, still more preferably 500,000 or less, and particularly preferably 450,000 or less. When the weight average molecular weight (Mw) of the polyamideimide resin is equal to or greater than the lower limit, the optical member containing the polyamideimide resin has better bending resistance. When the weight average molecular weight (Mw) of the polyamideimide resin is equal to or less than the above upper limit, the viscosity of the polyamideimide varnish can be kept low, and the optical member, particularly the optical film, can be easily stretched, so the workability is good. In the present invention, the weight average molecular weight (Mw) can be obtained by, for example, GPC measurement and standard polystyrene conversion, and can be specifically obtained by the method described in Examples.

In the polyamideimide resin, the content of the structural unit represented by formula (1) is preferably 10 mol% or more relative to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2), More preferably 15 mol% or more, still more preferably 18 mol% or more, particularly preferably 20 mol% or more, preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 60 mol% or less, particularly preferably 50 mol% or less. In the polyamide-imide resin, when the content of the structural unit represented by formula (1) is equal to or greater than the lower limit, the thickening due to hydrogen bonds between amide bonds in formula (2) can be suppressed, and the viscosity of the polyamide-imide varnish can be reduced. Therefore, it is easy to manufacture the optical member. In the said polyamide-imide resin, if the content rate of the structural unit represented by Formula (1) is below the said upper limit, the optical member which consists of the said polyamide-imide resin will exhibit high surface hardness. In addition, the said ratio can be measured using ¹ H-NMR, for example, or it can also be calculated from the introduction ratio of a raw material.

In the polyamideimide resin, the content of the structural unit represented by formula (2) is preferably 20 mol% or more relative to the total of the structural unit represented by formula (1) and the structural unit represented by formula (2); More preferably 30 mol% or more, still more preferably 40 mol% or more, particularly preferably 50 mol% or more, preferably 80 mol% or less, more preferably 70 mol% or less, still more preferably 60 mol% mol% or less, particularly preferably 50 mol% or less. In the polyamide-imide resin, when the content of the structural unit represented by formula (1) is equal to or less than the upper limit, the thickening due to the hydrogen bond between amide bonds in formula (2) can be suppressed, and the viscosity of the polyamide-imide varnish can be reduced. Therefore, it is easy to manufacture the optical member. In the said polyamide-imide resin, when the content rate of the structural unit represented by Formula (1) is more than the said lower limit, the optical member containing the said polyamide-imide resin exhibits high surface hardness. In addition, the said ratio can be measured using ¹ H-NMR, for example, or it can also be calculated from the introduction ratio of a raw material.

The polyamideimide resin has a glass transition temperature Tg calculated by tan δ in a dynamic viscoelasticity measurement (DMA measurement) of preferably less than 380°C, more preferably 379°C or less, and still more preferably 378°C or less. , for example, 370°C or less. When the glass transition temperature Tg of the polyamideimide resin is less than (or less than) the upper limit, the optical member made of the polyamideimide resin exhibits high surface hardness, low elastic modulus, and high flexibility. can In order to control the glass transition temperature within the above range, it is preferable to include, as a monomer constituting the polyamideimide, a monomer having a divalent group capable of imparting flexibility to the polyamideimide film obtained by film formation, and imparting flexibility. Examples of divalent groups that can be specifically include -O-, -CH ₂ -, -CF ₂ -, -C(CH ₃ ) ₂ -, and -C(CF ₃ ) ₂ -, which can impart flexibility. As the monomer having a possible divalent group, it is more preferable to include a monomer having a divalent group containing -O-. Moreover, the said glass transition temperature Tg of the said polyamideimide resin is normally 300 degreeC or more. The method of calculating the glass transition temperature by tan δ in the dynamic viscoelasticity measurement (DMA measurement) can be specifically performed as in the Examples.

In addition to the structural unit represented by Formula (1) and the structural unit represented by Formula (2), the said polyamide-imide resin has the structural unit represented by Formula (10-2), and/or the structural unit represented by Formula (11-2) units may be included.

In Formula (10-2), Y ¹ is each independently a tetravalent organic group, and is preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As Y ¹ , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) or formula The group represented by (29) and a tetravalent C6 or less chain hydrocarbon group are exemplified. The polyamide-imide resin according to one embodiment of the present invention may contain plural types of Y ¹ , and the plural types of Y ¹ may be the same as or different from each other.

In the formula (11-2), Y ² is a trivalent organic group, preferably an organic group in which a hydrogen atom in the organic group may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. As Y ² , formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula (26), formula (27), formula (28) Alternatively, a group in which any one of the bonds of the group represented by Formula (29) is substituted with a hydrogen atom, and a trivalent chain hydrocarbon group having 6 or less carbon atoms are exemplified. The polyamide-imide resin according to an embodiment of the present invention may contain plural types of Y ² , and the plural types of Y ² may be the same as or different from each other.

In formulas (10-2) and (11-2), X ¹ and X ² are each independently a divalent organic group, and preferably a hydrogen atom in the organic group is substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. It is an organic group which may be. As X ¹ and X ² , formula (10), formula (11), formula (12), formula (13), formula (14), formula (15), formula (16), formula (17) or formula (18) ) group represented by; groups in which hydrogen atoms in groups represented by these formulas are substituted with methyl, fluoro, chloro or trifluoromethyl groups; and a chain hydrocarbon group having 6 or less carbon atoms.

In one embodiment of the present invention, the polyamideimide resin is a structural unit represented by formula (1) and a structural unit represented by formula (2), and in some cases, formula (10-2) and/or formula (11) It consists of the constituent units represented by -2). Further, from the viewpoint of flexibility and surface hardness of the optical member comprising the polyamideimide resin, in the polyamideimide resin, the structural unit represented by formula (1) and the structural unit represented by formula (2) are (1) and formula (2), and based on the total structural units represented by formulas (10-2) and (11-2) as the case may be, preferably 80% or more, more preferably 90% or more, More preferably, it is 95% or more. In addition, in the polyamideimide resin, the content of the structural unit represented by formula (1) and the structural unit represented by formula (2) is formula (1) or formula (2), or in some cases, formula (10-2 ) Or it is usually 100% or less based on all structural units represented by Formula (11-2). In addition, the said content rate can be measured using ^<1> H-NMR, for example, or it can also be calculated from the introduction ratio of a raw material.

The polyamide-imide resin can be produced, for example, using a tetracarboxylic acid compound, a dicarboxylic acid compound, and a diamine compound described later as main raw materials. Here, the dicarboxylic acid compound includes at least a compound represented by formula (3'').

[In formula (3''), each of R ¹ to R ⁸ independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atom contained in R ¹ to R ⁸ is , may each independently be substituted with a halogen atom,

A represents -O-, -S-, -CO- or NR ⁹ -, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,

m is an integer from 1 to 4;

R ³¹ and R ³² are each independently —OH or Cl.]

In a preferred embodiment, the dicarboxylic acid compound is a compound represented by formula (3'') wherein A is -O-. In another preferred embodiment, the dicarboxylic acid compound is a compound represented by formula (3'') in which R ³² is -Cl. Moreover, you may use a diisocyanate compound instead of a diamine compound.

Examples of the tetracarboxylic acid compound used in the synthesis of the polyamideimide resin include aromatic tetracarboxylic acid compounds such as aromatic tetracarboxylic acid and an anhydride thereof, preferably a dianhydride thereof; and aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic acid and its anhydride, preferably its dianhydride. A tetracarboxylic acid compound may be used independently, and may use 2 or more types together. The tetracarboxylic acid compound may be an analog of a tetracarboxylic acid compound such as an acid chloride compound other than a dianhydride. These can be used individually or in combination of 2 or more types.

Examples of the aromatic tetracarboxylic dianhydride include non-condensed polycyclic aromatic tetracarboxylic dianhydride, monocyclic aromatic tetracarboxylic dianhydride, and condensed polycyclic aromatic tetracarboxylic dianhydride. Specific examples of non-fused polycyclic aromatic tetracarboxylic dianhydride include 4,4'-oxydiphthalic dianhydride (sometimes described as OPDA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (sometimes described as BPDA), 2, 2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfotetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenoxyphenyl) propane dianhydride, 4,4'-(hexafluoro Isopropylidene)diphthalic dianhydride (sometimes described as 6FDA), 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl) Ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, bis(3,4-dicarboxyphenyl) Methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride, 4,4'-(m-phenylenedioxy)diphthalic acid 2 Anhydride can be mentioned. In addition, 1,2,4,5-benzenetetracarboxylic dianhydride is used as monocyclic aromatic tetracarboxylic dianhydride, and 1,2,4,5-benzenetetracarboxylic is used as condensed polycyclic aromatic tetracarboxylic dianhydride. As the aromatic tetracarboxylic dianhydride in which the main acid dianhydride is condensed polycyclic, 2,3,6,7-naphthalenetetracarboxylic dianhydride is exemplified. These can be used individually or in combination of 2 or more types.

Among these, 4,4'-oxydiphthalic acid dianhydride, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride, 2,2',3,3'-benzophenone tetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfotetra Carboxylic acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4 -Dicarboxyphenoxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride, 1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1 -bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride , bis(3,4-dicarboxyphenyl)methane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, 4,4'-(p-phenylenedioxy)diphthalic dianhydride and 4,4' -(m-phenylenedioxy)diphthalic dianhydride is preferred, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'- (Hexafluoroisopropylidene)diphthalic dianhydride is more preferable.

Examples of the aliphatic tetracarboxylic dianhydride include cyclic or acyclic aliphatic tetracarboxylic dianhydride. Cyclic aliphatic tetracarboxylic dianhydride is tetracarboxylic dianhydride having an alicyclic hydrocarbon structure, and specific examples thereof include 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4- Cycloalkane tetracarboxylic dianhydride such as cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-en-2,3, 5,6-tetracarboxylic dianhydride, dicyclohexyl 3,3'-4,4'-tetracarboxylic dianhydride, and positional isomers thereof. These can be used individually or in combination of 2 or more types. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and 1,2,3,4-pentanetetracarboxylic dianhydride. or a combination of two or more may be used. Moreover, you may use combining cyclic aliphatic tetracarboxylic dianhydride and acyclic aliphatic tetracarboxylic dianhydride.

Among the tetracarboxylic dianhydrides, 4,4'-oxydiphthalic dianhydride, 3,3',4,4 from the viewpoints of high surface hardness, high flexibility, high bending resistance, high transparency, and low colorability of optical members '-benzophenonetetracarboxylic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3' ,4,4'-diphenylsulfotetracarboxylic acid dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride , and mixtures thereof are preferred, 4,4'-oxydiphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride and 4,4'-(hexafluoroisopropylidene )diphthalic dianhydride, and mixtures thereof are more preferred, and 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride is still more preferred.

As the dicarboxylic acid compound used in the synthesis of the polyamideimide resin, 4,4'-oxybisbenzoic acid and/or acid chloride compounds thereof are preferably used. Specifically, 4,4'-oxybis (benzoyl chloride) is mentioned as a preferable example. In addition to 4,4'-oxybisbenzoic acid or its acid chloride compound, other dicarboxylic acid compounds may be used. As another dicarboxylic acid compound, aromatic dicarboxylic acid, aliphatic dicarboxylic acid, and their derivative acid chloride compound, acid anhydride, etc. are mentioned, You may use 2 or more types together. As a specific example, terephthalic acid; isophthalic acid; naphthalenedicarboxylic acid; 4,4'-biphenyldicarboxylic acid; 3,3'-biphenyldicarboxylic acid; A dicarboxylic acid compound of a chain hydrocarbon having 8 or less carbon atoms and two benzoic acids connected by a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or a phenylene group. compounds and their acid chloride compounds. Specifically, terephthaloyl chloride is exemplified as a preferred example.

In addition, the polyamide-imide resin, in addition to the tetracarboxylic acid compound used in the polyamide-imide synthesis, tetracarboxylic acid and Tricarboxylic acids and their anhydrides and derivatives may be further reacted.

As tetracarboxylic acid, the water adduct of the anhydride of the said tetracarboxylic acid compound is mentioned.

As a tricarboxylic acid compound, aromatic tricarboxylic acid, aliphatic tricarboxylic acid, and their derivative acid chloride compounds, acid anhydrides, etc. are mentioned, You may use 2 or more types together.

Specific examples include anhydrides of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalene tricarboxylic acid-2,3-anhydride; and compounds in which phthalic anhydride and benzoic acid are connected by a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ - or a phenylene group.

As a diamine compound used for the synthesis|combination of polyamideimide resin, aliphatic diamine, aromatic diamine, and mixtures thereof are mentioned, for example. In the present embodiment, "aromatic diamine" refers to diamine in which an amino group is directly bonded to an aromatic ring, and may contain an aliphatic group or other substituent in a part of its structure. This aromatic ring may be a monocyclic ring or a condensed ring, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring and a fluorene ring, but are not limited thereto. Among these, a benzene ring is preferable. In addition, "aliphatic diamine" represents diamine in which an amino group is directly bonded to an aliphatic group, and may contain an aromatic ring or other substituents in a part of its structure.

Examples of the aliphatic diamine include acyclic aliphatic diamines such as hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, norbornanediamine and 4, and cyclic aliphatic diamines such as 4'-diaminodicyclohexylmethane. These can be used individually or in combination of 2 or more types.

Examples of aromatic diamine include p-phenylenediamine, m-phenylenediamine, 2,4-toluenediamine, m-xylylenediamine, p-xylylenediamine, 1,5-diaminonaphthalene, and aromatic diamines having one aromatic ring such as 2,6-diaminonaphthalene; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether (sometimes described as ODA), 3,4'-diaminodi Phenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4 -bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-diaminodiphenylsulfone, bis[4-(4-aminophenoxy)phenyl]sulfone , bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy) Phenyl] propane, 2,2'-dimethylbenzidine (sometimes written as MB), 2,2'-bis(trifluoromethyl)benzidine (sometimes written as TFMB), 4,4'-bis (4-aminophenoxy) biphenyl, 9,9-bis (4-aminophenyl) fluorene, 9,9-bis (4-amino-3-methylphenyl) fluorene, 9,9-bis (4-amino Aromatic diamines having two or more aromatic rings, such as -3-chlorophenyl)fluorene and 9,9-bis(4-amino-3-fluorophenyl)fluorene; These can be used individually or in combination of 2 or more types.

As aromatic diamine, preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether , 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl] Sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy) ) Phenyl] propane, 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl, 4,4'-bis (4-aminophenoxy) phenyl, more preferably 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone , 1,4-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2 ,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl, and 4,4'-bis(4-aminophenoxy)biphenyl. These can be used individually or in combination of 2 or more types.

Among the above diamine compounds, it is preferable to use at least one selected from the group consisting of aromatic diamines having a biphenyl structure from the viewpoint of high surface hardness, high flexibility, high bending resistance, high transparency and low colorability of the optical member. Consisting of 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)benzidine, 4,4'-bis(4-aminophenoxy)biphenyl and 4,4'-diaminodiphenyl ether It is more preferable to use at least one selected from the group, and it is even more preferable to use 2,2'-bis(trifluoromethyl)benzidine.

The polyamideimide resin, which is an embodiment of the present invention, is a diamine compound, a tetracarboxylic acid compound (an acid chloride compound, a tetracarboxylic acid compound analog such as tetracarboxylic dianhydride), and a dicarboxylic acid compound (acid chloride compound, etc.) It is a condensation-type polymer that is a polycondensation product of a dicarboxylic acid compound analogue), and in some cases a tricarboxylic acid compound (an analogue of a tricarboxylic acid compound such as an acid chloride compound or a tricarboxylic acid anhydride). Structural units represented by formula (1) and formula (10-2) are usually derived from diamines and tetracarboxylic acid compounds. The structural unit represented by Formula (2) is normally derived from a diamine and a dicarboxylic acid compound. The structural unit represented by Formula(11-2) is usually derived from a diamine and a tricarboxylic acid compound.

In a preferred embodiment of the present invention, the polyamideimide resin may contain a halogen atom as described above. Specific examples of the fluorine-containing substituent include a fluoro group and a trifluoromethyl group. By containing a halogen atom in the polyamide-imide resin, the yellowness (sometimes described as YI) of an optical member made of the polyamide-imide resin can be reduced in some cases, and further high flexibility and bending resistance can be obtained. They tend to be compatible. Further, the halogen atom is preferably a fluorine atom from the viewpoints of reducing the yellowness of the optical member (namely, improving transparency), reducing the water absorption, and bending resistance.

The content of halogen atoms in the polyamide-imide resin is preferably based on the mass of the polyamide-imide resin from the viewpoint of reducing the yellowness (improving transparency), reducing the water absorption, and suppressing deformation of the optical member. is 1 to 40% by mass, more preferably 3 to 35% by mass, and still more preferably 5 to 32% by mass.

In one embodiment of the present invention, an imidation catalyst may be present in the synthesis reaction of polyamideimide resin. Examples of the imidation catalyst include aliphatic amines such as tripropylamine, dibutylpropylamine, and ethyldibutylamine; alicyclic amines (monocyclic) such as N-ethylpiperidine, N-propylpiperidine, N-butylpyrrolidine, N-butylpiperidine, and N-propylhexahydroazepine; alicyclic amines (polycyclic) such as azabicyclo[2.2.1]heptane, azabicyclo[3.2.1]octane, azabicyclo[2.2.2]octane, and azabicyclo[3.2.2]nonane; and pyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-dimethylpyridine, 2,4,6-trimethylpyridine, 3 and aromatic amines such as ,4-cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline, and isoquinoline.

The reaction temperature of the diamine compound, the tetracarboxylic acid compound, and the dicarboxylic acid compound is not particularly limited, but is, for example, 50 to 350°C. The reaction time is also not particularly limited, but is, for example, about 30 minutes to 10 hours. If necessary, the reaction may be performed under an inert atmosphere or reduced pressure. In addition, the reaction may be performed in a solvent, and examples of the solvent include solvents described below used for preparation of polyamideimide varnish.

(optical member)

In another embodiment of the present invention, an optical member that is a polyamideimide film containing the polyamideimide resin is also provided. As an optical member, an optical film is mentioned, for example. Since the said optical member is excellent in flexibility, bending resistance, and surface hardness, it is suitable as the front plate of an image display apparatus, especially the front plate (window film) of a flexible display. A single layer or a multi-layer may be sufficient as an optical member. When the optical member is a multilayer, each layer may have the same composition or a different composition.

In one embodiment of the present invention, the content of the polyamideimide resin in the optical member is preferably 40% by mass or more, more preferably 50% by mass or more, based on the total mass of the optical member. It is preferably 70% by mass or more, particularly preferably 80% by mass or more, and very preferably 90% by mass or more. When the content of the polyamide-imide resin is equal to or greater than the lower limit, the bending resistance of the optical member is good. Moreover, the content rate of polyamide-imide resin in an optical member is 100 mass % or less normally on the basis of the total mass of an optical member.

(inorganic material)

The optical member may further contain inorganic materials such as inorganic particles in addition to polyamideimide resin. Examples of the inorganic material include inorganic particles such as titania particles, alumina particles, zirconia particles, and silica particles, and silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate. From the viewpoint of the stability of the polyamideimide varnish for producing an optical member, the inorganic material is preferably inorganic particles, particularly silica particles. The inorganic particles may be bonded to each other by a molecule having a siloxane bond (ie, -SiOSi-).

The average primary particle diameter of the inorganic particles is preferably 10 to 100 nm, more preferably 20 to 80 nm, from the viewpoints of transparency of the optical member, mechanical properties, and suppression of aggregation of the inorganic particles. In the present invention, the average primary particle size can be determined by measuring the 10-point average value of the positive direction diameters using a transmission electron microscope.

The content of the inorganic material in the optical member is preferably 0% by mass or more and 90% by mass or less, more preferably 0.01% by mass or more and 60% by mass or less, still more preferably 5% by mass, based on the total mass of the optical member. % or more and 40 mass % or less. When the content of the inorganic material is within the above range, it tends to be easy to achieve both transparency and mechanical properties of the optical member.

(ultraviolet ray absorbent)

The optical member may contain 1 type, or 2 or more types of ultraviolet absorbers. The ultraviolet absorber can be appropriately selected from those commonly used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light having a wavelength of 400 nm or less. Examples of the ultraviolet absorber include at least one compound selected from the group consisting of benzophenone-based compounds, salicylate-based compounds, benzotriazole-based compounds, and triazine-based compounds. Since deterioration of polyamide-imide resin is suppressed when an optical member contains a ultraviolet absorber, the visibility of an optical member can be improved.

In the present specification, a "system compound" refers to a derivative of a compound to which the "system compound" is given. For example, "benzophenone compound" refers to a compound having benzophenone as a parent skeleton and a substituent bonded to benzophenone.

When the optical member contains a UV absorber, the content of the UV absorber is preferably 1% by mass or more, more preferably 2% by mass or more, and still more preferably 3% by mass or more with respect to the total mass of the optical member. , Preferably it is 10 mass % or less, More preferably, it is 8 mass % or less, More preferably, it is 6 mass % or less. Although the preferable content rate varies depending on the ultraviolet absorber used, adjusting the content rate of the ultraviolet absorber so that the light transmittance of 400 nm is about 20 to 60% can improve the light resistance of the optical member and obtain an optical member with high transparency. can

(other additives)

The optical member may also contain other additives. Examples of other components include antioxidants, release agents, stabilizers, bluing agents, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners, and leveling agents.

The content of the other additives is preferably 0% by mass or more and 20% by mass or less, more preferably 0% by mass or more and 10% by mass or less, based on the mass of the optical member.

The thickness of the optical member, particularly the optical film, is appropriately adjusted depending on the application, but is usually 10 to 1000 µm, preferably 15 to 500 µm, more preferably 20 to 400 µm, and still more preferably 25 to 300 µm. Further, in the present invention, the thickness can be measured by a contact type digimatic indicator.

The optical member WHEREIN: The total light transmittance Tt based on JIS K 7105:1981 is preferably 70% or more, more preferably 80% or more, still more preferably 85% or more, and particularly preferably 90% or more. When the total light transmittance Tt of an optical member is more than the said lower limit, when an optical member is incorporated in an image display apparatus, sufficient visibility is securable. Moreover, the upper limit of the total light transmittance Tt of an optical member is 100% or less normally.

(Method of manufacturing optical member)

The method for manufacturing the optical member, particularly the optical film, is not particularly limited as long as the optical member contains the polyamideimide resin. In one embodiment of the present invention, the optical member, particularly the optical film, is, for example, the following steps:

(a) a step of applying a liquid containing polyamideimide resin (polyamideimide varnish) to a substrate to form a coating film (application step), and

(b) It can be manufactured by a manufacturing method including a step of drying the applied liquid (polyamideimide varnish) to form an optical member, particularly an optical film (polyamideimide film) (formation step). Steps (a) and (b) can usually be performed in this order.

In the application step, first, a liquid containing polyamide-imide resin (polyamide-imide varnish) is prepared. For the preparation of the polyamideimide varnish, the diamine compound, the tetracarboxylic acid compound, the dicarboxylic acid compound, and other components such as a tertiary amine acting as an imidation catalyst, a dehydrating agent, and the like are mixed as necessary, and the reaction to prepare a polyamideimide mixture. As a tertiary amine, the above-mentioned aromatic amine, aliphatic amine, etc. are mentioned. Examples of the dehydrating agent include acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride, and isovaleric anhydride. A poor solvent is added to this polyamide-imide mixture, the polyamide-imide resin is precipitated by a reprecipitation method, dried, and taken out as a precipitate.

The polyamide-imide resin precipitate taken out is dissolved in a solvent, and a liquid containing polyamide-imide resin (polyamide-imide varnish) is prepared by adding and stirring the ultraviolet absorber and other additives as necessary.

The solvent used for preparing the polyamideimide varnish is not particularly limited as long as it can dissolve the polyamideimide resin. Examples of such a solvent include amide solvents such as N,N-dimethylacetamide and N,N-dimethylformamide; lactone solvents such as γ-butyrolactone and γ-valerolactone; sulfur-containing solvents such as dimethyl sulfone, dimethyl sulfoxide, and sulfolane; carbonate solvents such as ethylene carbonate and propylene carbonate; and combinations thereof (mixed solvents). Among these solvents, amide-based solvents or lactone-based solvents are preferred. Further, the polyamideimide varnish may contain water, an alcohol solvent, a ketone solvent, an acyclic ester solvent, an ether solvent, or the like.

Subsequently, a coating film is formed by casting or the like using a polyamideimide varnish on a substrate such as a resin substrate, a SUS belt, or a glass substrate by a known roll-to-roll or batch method, for example. can form

In the forming step, the optical member can be formed by drying the coating film and peeling it from the base material. You may perform the drying process of drying an optical member further after peeling. Drying of the coating film can be normally performed at a temperature of 50 to 350°C. If necessary, the coating film may be dried in an inert atmosphere or under reduced pressure.

You may perform the surface treatment process of giving surface treatment to the surface of at least one side of an optical member. As surface treatment, UV ozone treatment, plasma treatment, and corona discharge treatment are mentioned, for example.

Examples of the resin substrate include PET film, PEN film, polyimide film, and polyamideimide film. Among them, from the viewpoint of excellent heat resistance, a PET film, a PEN film, a polyimide film, and other polyamideimide films are preferable. Further, from the viewpoints of adhesiveness with optical members and cost, a PET film is more preferred.

[functional layer]

An optical member according to an embodiment of the present invention may include a functional layer. Examples of the functional layer include layers having various functions such as a UV absorbing layer, an adhesive layer, a color adjusting layer, and a refractive index adjusting layer. The optical member may be provided with one or a plurality of functional layers. Also, one functional layer may have a plurality of functions.

The ultraviolet absorbing layer is a layer having a function of absorbing ultraviolet rays, and includes, for example, a main material selected from ultraviolet curable transparent resins, electron beam curable transparent resins, and thermosetting transparent resins, and dispersed in the main material. Composed of UV absorbers. By providing an ultraviolet ray absorbing layer as a functional layer, a change in yellowness due to light irradiation can be easily suppressed.

The adhesive layer is a layer having an adhesive function, and has a function of adhering an optical member to another member. As the material for forming the adhesive layer, a commonly known material can be used. For example, a thermosetting resin composition or a photocurable resin composition can be used.

The adhesive layer may be composed of a resin composition containing a component having a polymerizable functional group. In this case, strong adhesion can be realized by further polymerizing the resin composition constituting the adhesive layer after the optical member is brought into close contact with the other member. The adhesive strength between the optical member and the pressure-sensitive adhesive layer may be 0.1 N/cm or more or 0.5 N/cm or more.

The adhesive layer may contain a thermosetting resin composition or a photocurable resin composition as a material. In this case, the resin composition can be polymerized and cured by supplying energy ex post facto.

The pressure-sensitive adhesive layer may be a layer composed of an adhesive called a pressure sensitive adhesive (PSA) that adheres to an object by pressure. The pressure-sensitive adhesive may be an adhesive that is “a substance that has adhesiveness at room temperature and adheres to adherends with light pressure” (JIS K6800), or “a specific component is incorporated into a protective film (microcapsule) and suitable means An adhesive capable of maintaining stability until the film is destroyed by (pressure, heat, etc.)” (JIS K6800) may be a capsule type adhesive.

A color adjustment layer is a layer which has a function of color adjustment, and is a layer which can adjust an optical member to a target color. A color adjusting layer is a layer containing resin and a coloring agent, for example. Examples of the coloring agent include inorganic pigments such as titanium oxide, zinc oxide, bengala, titanium oxide-based fired pigments, ultramarine blue, cobalt aluminate, and carbon black; organic pigments such as azo-based compounds, quinacridone-based compounds, anthraquinone-based compounds, perylene-based compounds, isoindolinone-based compounds, phthalocyanine-based compounds, quinophthalone-based compounds, threnic compounds, and diketopyrrolopyrrole-based compounds; extender pigments such as barium sulfate and calcium carbonate; and dyes such as basic dyes, acid dyes, and mordant dyes.

The refractive index adjustment layer is a layer having a refractive index adjustment function, has a refractive index different from that of the optical member, and is a layer capable of imparting a predetermined refractive index to the optical member. The refractive index adjusting layer may be, for example, a resin layer containing an appropriately selected resin and, in some cases, a pigment, or may be a metal thin film.

As a pigment for adjusting the refractive index, silicon oxide, aluminum oxide, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide are exemplified. The average primary particle diameter of the pigment may be 0.1 μm or less. By setting the average primary particle diameter of the pigment to 0.1 μm or less, irregular reflection of light passing through the refractive index adjusting layer can be prevented, and a decrease in transparency can be prevented.

As a metal used for a refractive index adjustment layer, metals, such as titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, silicon nitride, for example oxides or metal nitrides.

Moreover, the optical member may be provided with a hard coat layer. As the hard coating layer, well-known hard coatings such as acrylic, epoxy, urethane, benzyl chloride, and vinyl are exemplified. Further, in a preferred embodiment of the present invention, the optical member can develop high surface hardness even without a hard coat layer. For this reason, the hard coat layer laminate containing the optical member made of the polyamide-imide resin can express higher surface hardness than the hard coat laminate containing the optical member which cannot express high surface hardness alone.

The said optical member can express high surface hardness. In a preferred embodiment of the present invention, the surface hardness of the optical member is preferably 2B or more, more preferably B or more, still more preferably HB or more, particularly preferably H or more, very preferably 2H or more to be. If the surface hardness of the optical member is equal to or greater than the lower limit, it is possible to advantageously suppress scratches on the surface of the image display device when used as a front plate (window film) of the image display device, and also contribute to preventing shrinkage and expansion of the optical member. can Moreover, the surface hardness of an optical member is 9H or less normally. Further, in the present invention, the surface hardness can be measured according to JIS K5600-5-4: 1999, for example, the load is 100 g, the scanning speed is 60 mm / min, and the presence or absence of scratches in an environment of 4000 lux evaluation can be made. Using the flexibility of the flexible display, the image display device can be made into various shapes as well as the flat shape. opportunities increase. For this reason, the optical member of one embodiment of the present invention is very useful as a front plate of a flexible display.

The said optical member can express high flexibility. In a preferred embodiment of the present invention, the modulus of elasticity of the optical member is preferably 5.9 GPa or less, more preferably 5.5 GPa or less, still more preferably 5.2 GPa or less, particularly preferably 5.0 GPa or less, very preferably is less than 4.5 GPa. If the modulus of elasticity of the optical member is equal to or less than the above upper limit value, when the flexible display is bent, damage to other members by the optical member can be suppressed. Moreover, the elasticity modulus of an optical member is 2.0 GPa or more normally. The modulus of elasticity is determined by measuring the S-S curve of a test piece having a width of 10 mm under conditions of a distance between chucks of 500 mm and a tensile speed of 20 mm/min using, for example, Autograph AG-IS manufactured by Shimadzu Corporation. can be measured

The said optical member, especially an optical film, can express excellent bending resistance. In a preferred embodiment of the present invention, the number of reciprocating bends until breakage of the optical member is preferably 10,000 times as measured by R = 1 mm, 135 °, weight 0.75 kgf, and speed 175 cpm. or more, more preferably 20,000 or more, still more preferably 30,000 or more, particularly preferably 40,000 or more, and very preferably 50,000 or more. If the number of times of reciprocating bending of the optical member is equal to or greater than the above lower limit, wrinkles that may occur when the optical member is bent can be further suppressed. In addition, although the number of reciprocal bending of the optical member is not limited, it is usually sufficiently practical if it can be bent 1,000,000 times. The number of reciprocating bends can be determined using a test piece (optical member) with a thickness of 50 μm and a width of 10 mm, for example, with an MIT internal bending fatigue tester (model 0530) manufactured by Toyo Seiki Seisakusho Co., Ltd.

The said optical member can express excellent transparency. For this reason, the said optical member is very useful as a front plate (window film) of an image display apparatus, especially a flexible display. In a preferred embodiment of the present invention, the yellowness YI of the optical member in accordance with JIS K 7373:2006 is preferably 5 or less, more preferably 3 or less, still more preferably 2.5 or less. An optical member whose yellowness YI is equal to or less than the above upper limit can contribute to high visibility of a display device or the like. Further, the yellowness of the optical member is preferably 0 or more.

An optical member, particularly an optical film, which is an embodiment of the present invention is useful as a front plate of an image display device, particularly a front plate (window film) of a flexible display. The optical member can be disposed as a front plate on the viewer-side surface of an image display device, particularly a flexible display. This front plate has a function of protecting the image display elements in the flexible display. Since the image display device including the optical member has high flexibility and bending resistance and high surface hardness, when bent, other members are not damaged, and creases are not easily generated in the optical member itself, Additionally, scratches on the surface can be advantageously suppressed.

Examples of image display devices include televisions, smart phones, mobile phones, car navigation systems, tablet PCs, portable game consoles, electronic paper, indicators, bulletin boards, watches, and wearable devices such as smart watches. Examples of flexible displays include image display devices having flexible characteristics, such as televisions, smart phones, mobile phones, car navigation systems, tablet PCs, portable game machines, electronic papers, indicators, bulletin boards, watches, and wearable devices.

Example

Hereinafter, the present invention will be described in more detail by examples. "%" and "part" in the examples mean mass % and mass part unless otherwise specified. First, the evaluation method will be described.

<Measurement of modulus of elasticity>

The elastic modulus of the polyamideimide films obtained in Examples was measured using Autograph AG-IS manufactured by Shimadzu Corporation. A film with a width of 10 mm was produced, the S-S curve was measured under conditions of a distance between chucks of 500 mm and a tensile speed of 20 mm/min, and the modulus of elasticity was calculated from the inclination.

<Surface hardness measurement>

As the surface hardness of the polyamide-imide film obtained in the examples, the pencil hardness of the film surface was adopted based on JIS K5600-5-4:1999. The load was 100 g and the scanning speed was 60 mm/min, and the presence or absence of scratches was evaluated in an environment of 4000 lux.

<Measurement of bending tolerance>

The bending resistance of the polyamideimide film obtained in the examples was measured using an MIT bending fatigue tester (model 0530) manufactured by Toyo Seiki Seisakusho Co., Ltd. A film having a thickness of 50 μm and a width of 10 mm was produced, and the number of reciprocal bending until breaking was evaluated when measured at 135° at R = 1 mm, at a weight of 0.75 kgf, and at a speed of 175 cpm.

<Measurement of weight average molecular weight (Mw)>

Gel permeation chromatography (GPC) measurements

(1) Pretreatment method

A DMF eluent (10 mM lithium bromide solution) was added to the sample so as to have a concentration of 2 mg/mL, heated while stirring at 80°C for 30 minutes, cooled, and filtered through a 0.45 µm membrane filter to obtain a measurement solution.

(2) Measurement conditions

Column: TSKgel SuperAWM-H × 2 + SuperAW2500 × 1 (6.0 mm I.D. × 150 mm × 3) (all manufactured by Tosoh Corporation)

Eluent: DMF (added 10 mM lithium bromide)

Flow rate: 1.0 mL/min.

Detector: RI detector

Column temperature: 40°C

Injection volume: 100 μL

Molecular Weight Standard: Standard Polystyrene

<Measurement of total light transmittance (Tt)>

The total light transmittance Tt of the polyamideimide films obtained in Examples was measured by a fully automatic direct reading haze computer HGM-2DP manufactured by Suga Test Instruments Co., Ltd. in accordance with JIS K7105:1981.

<Measurement of Yellowness Index (YI)>

The yellowness (Yellow Index: YI) of the polyamideimide films obtained in Examples was measured in accordance with JIS K 7373: 2006 using an ultraviolet-visible and near-infrared spectrophotometer V-670 manufactured by Nippon Spectrosco. did. After performing the background measurement in the absence of the film, the film was set in the sample holder, and the transmittance to light of 300 to 800 nm was measured to obtain tristimulus values (X, Y, Z). YI was computed based on the following formula.

YI=100×(1.2769X-1.0592Z)/Y

<Measurement of glass transition temperature (Tg)>

Using a DMA Q800 manufactured by TA Instruments, the polyamideimide film obtained in the examples was used as the following sample and measured under the following conditions to obtain a tan δ curve representing the ratio of the loss elastic modulus to the storage elastic modulus. Tg was calculated from the peak of the tan-delta curve.

-Sample: length 5-15 mm, width 5 mm

-Experiment Mode: DMA Multi-Frequency-Strain

-Experimental mode detailed conditions:

(1) Clamp:Tension:Film

(2) Amplitude: 5㎛

(3) Frequncy: 10Hz (no change in the entire temperature range)

(4) Preload Force: 0.01N

(5) Force Track: 125N

-Temperature conditions: (1) Temperature increase range: room temperature ~ 400℃, (2) temperature increase rate: 5℃/min

-Main collected data: (1) Storage modulus (E'), (2) Loss modulus (E''), (3) tanδ (E''/E')

Example 1

[Preparation of polyamideimide resin (1)]

In a nitrogen atmosphere, in a 1 L separable flask equipped with a stirring blade, 2,2'-bis (trifluoromethyl) benzidine (TFMB) 52 g (162.38 mmol) and N, N-dimethylacetamide (DMAc) 734.10 g was added, and TFMB was dissolved in DMAc with stirring at room temperature. Then, 28.90 g (65.05 mmol) of 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA) was added to the flask, and the mixture was stirred at room temperature for 3 hours. Thereafter, 28.80 g (97.57 mmol) of 4,4'-oxybis(benzoyl chloride) (OBBC) was added to the flask, and the mixture was stirred at room temperature for 1 hour. Then, 7.49 g (94.65 mmol) of pyridine and 26.56 g (260.20 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C. using an oil bath, and stirred for further 3 hours. , to obtain a reaction solution.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a thread shape, and the precipitate was taken out and washed with methanol after being immersed in methanol for 6 hours. Subsequently, the precipitate was dried under reduced pressure at 100°C to obtain polyamideimide resin (1).

[Formation of polyamideimide film (1)]

To the obtained polyamide-imide resin (1), DMAc was added to a concentration of 15% by mass to prepare a polyamide-imide varnish (1). The obtained polyamideimide varnish (1) was applied on a smooth surface of a polyester base material (manufactured by Toyobo Co., Ltd., trade name "A4100") using an applicator so that the film thickness of a self-supporting film was 55 µm. , 50°C for 30 minutes and then dried at 140°C for 15 minutes to obtain a self-supporting film. The self-supporting film was fixed to a metal frame and further dried at 300°C for 30 minutes in a nitrogen atmosphere to obtain a polyamideimide film (1) having a thickness of 50 µm. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (1) were measured. Mw was 120,000, Tt was 91%, YI was 2.2, Tg was 345°C. In addition, the molar ratio of each component is shown in Table 1.

Example 2

[Preparation of polyamideimide resin (2)]

The amount of DMAc was 701.64g, the amount of 6FDA was 14.45g (32.52mmol), the amount of OBBC was 38.39g (130.10mmol), the amount of pyridine was 9.98g (126.20mmol), and the amount of acetic anhydride was 13.28g. Polyamide-imide resin (2) was obtained in the same manner as in Example 1 [Preparation of polyamide-imide resin (1)] except for changing to (130.10 mmol). In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (2)]

Polyamideimide having a film thickness of 50 μm was prepared in the same manner as in Example 1 [Film formation of polyamideimide film (1)] except that polyamideimide resin (2) was used instead of polyamideimide resin (1). Film (2) was obtained. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI and glass transition temperature Tg of the polyamideimide film (2) were measured. Mw was 150,000, Tt was 91%, YI was 2.5, Tg was 345°C.

Example 3

[Preparation of polyamideimide resin (3)]

In a nitrogen gas atmosphere, TFMB 52g (162.38mmol) and DMAc 697.82g were added to a 1L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc with stirring at room temperature. Then, 6FDA 21.67g (48.79mmol) was added to the flask, and it stirred at room temperature for 3 hours. After that, 24.00 g (81.31 mmol) of OBBC and then 6.60 g (32.52 mmol) of terephthaloyl chloride (TPC) were added to the flask, and the mixture was stirred at room temperature for 1 hour. Then, 8.73 g (110.42 mmol) of pyridine and 19.92 g (195.15 mmol) of acetic anhydride were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C. using an oil bath, and further stirred for 3 hours, A reaction solution was obtained.

The obtained reaction liquid was cooled to room temperature, put into a large amount of methanol in a thread shape, and the precipitate was taken out and washed with methanol after being immersed in methanol for 6 hours. Subsequently, the precipitate was dried under reduced pressure at 100°C to obtain polyamideimide resin (3). In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (3)]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as [Film formation of polyamide-imide film (1)] in Example 1, except that polyamide-imide resin (3) was used instead of polyamide-imide resin (1). Film (3) was obtained. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (3) were measured. Mw was 100,000, Tt was 91%, YI was 2.3, Tg was 340°C.

Example 4

[Preparation of polyamideimide resin (4)]

The amount of DMAc was 667.75g, the amount of 6FDA was 21.67g (162.38mmol), the amount of OBBC was 9.60g (48.79mmol), the amount of TPC was 16.51g (81.31mmol), and the amount of pyridine was 8.73g ( 110.42 mmol) and polyamide-imide resin (4) in the same manner as [Preparation of polyamide-imide resin (3)] in Example 3, except that the amount of acetic anhydride was changed to 19.92 g (195.15 mmol). got In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (4)]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as [Film formation of polyamide-imide film (1)] in Example 1, except that polyamide-imide resin (4) was used instead of polyamide-imide resin (1). Film (4) was obtained. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (4) were measured. Mw was 230,000, Tt was 91%, YI was 2.3, Tg was 369°C.

Example 5

[Preparation of polyamideimide resin (5)]

The amount of DMAc was 884.53g, the amount of 6FDA was 21.67g (38.79mmol), the amount of OBBC was 4.80g (16.26mmol), the amount of TPC was 19.81g (97.57mmol), and the amount of pyridine was 8.73g ( 110.42 mmol) and polyamide-imide resin (5) in the same manner as [Preparation of polyamide-imide resin (3)] in Example 3, except that the amount of acetic anhydride was changed to 19.92 g (195.15 mmol). got In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (5)]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as [Formation of polyamide-imide film (1)] in Example 1, except that polyamide-imide resin (5) was used instead of polyamide-imide resin (1). A film (5) was obtained. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (5) were measured. Mw was 345,000, Tt was 91%, YI was 2.2, Tg was 377°C.

Example 6

[Preparation of polyamideimide resin (6)]

The amount of DMAc was 849.23g, the amount of 6FDA was 14.45g (32.52mmol), the amount of OBBC was 4.80g (16.26mmol), the amount of TPC was 23.11g (113.84mmol), and the amount of pyridine was 9.98g ( 126.20 mmol) and polyamide-imide resin (6) in the same manner as [Preparation of polyamide-imide resin (3)] in Example 3, except that the amount of acetic anhydride was changed to 13.28 g (130.10 mmol). got In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (6)]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as [Film formation of polyamide-imide film (1)] in Example 1, except that polyamide-imide resin (6) was used instead of polyamide-imide resin (1). A film (6) was obtained. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (6) were measured. Mw was 341,000, Tt was 91%, YI was 2.4, Tg was 378°C.

Comparative Example 1

[Preparation of polyamideimide resin (7)]

The amount of DMAc was 647.70g, the amount of 6FDA was 21.67g (48.79mmol), the amount of TPC was 23.11g (113.84mmol), the amount of pyridine was 8.73g (110.42mmol), and the amount of acetic anhydride was 19.92g. A polyamide-imide resin (7) was obtained in the same manner as in [Preparation of polyamide-imide resin (3)] in Example 3, except for changing to (195.15 mmol) and not adding OBBC. In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (7)]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as in Example 1 [Formation of polyamide-imide film (1)] except that polyamide-imide resin (7) was used instead of polyamide-imide resin (1). Film (7) was obtained. According to the above measurement method, the weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (7) were measured. Mw was 80,000, Tt was 90%, YI was 2.4, Tg was 380°C.

Comparative Example 2

[Preparation of polyimide resin (8)]

The amount of DMAc was changed to 831.46 g, the amount of 6FDA was changed to 72.24 g (162.62 mmol), the amount of pyridine was changed to 18.72 g (236.62 mmol), and the amount of acetic anhydride was changed to 66.41 g (650.49 mmol), and OBBC A polyimide resin (8) was obtained in the same manner as in Example 1 [Preparation of polyamideimide resin (1)] except that no was added. In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyimide film (8)]

A polyimide film having a film thickness of 50 μm ( 8) was obtained. The weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyimide film (8) were measured according to the above measurement method. Mw was 268,000, Tt was 92%, YI was 2.0, Tg was 361 °C.

Comparative Example 3

[Preparation of polyimide resin (9)]

The amount of DMAc was changed to 732.20 g, the amount of 6FDA was changed to 28.9 g (65.05 mmol), the amount of pyridine was changed to 18.72 g (236.62 mmol), and the amount of acetic anhydride was changed to 66.41 g (650.49 mmol), and OBBC [Polyamideimide resin (1) Preparation], polyimide resin (9) was obtained. In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyimide film (9)]

A polyimide film having a film thickness of 50 μm ( 9) was obtained. The weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyimide film (9) were measured according to the above measurement method. Mw was 276,000, Tt was 85%, YI was 5.8, Tg was 365 ° C.

Example 7

[Preparation of polyamideimide resin (10)]

45.00 g (140.5 mmol) of TFMB and 600.9 g of DMAc were added to a 1 L separable flask equipped with a stirring blade under a nitrogen gas atmosphere, and TFMB was dissolved in DMAc while stirring at room temperature. Subsequently, after adding 4.14 g (14.1 mmol) of BPDA to the flask and stirring at room temperature for 2.5 hours, 25.01 g (56.3 mmol) of 6FDA was added and the mixture was stirred at room temperature for 15 hours. Further, 4.15 g (14.1 mmol) of OBBC and 11.43 g (56.3 mmol) of TPC were added to the flask and stirred at room temperature for 1 hour. Next, 21.55 g (211.1 mmol) of acetic anhydride and 3.28 g (35.2 mmol) of 4-picoline were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C. using an oil bath, and further 3 hours. By stirring, a reaction solution was obtained.

After cooling the obtained reaction solution to room temperature, 647 g of methanol and 180 g of ion-exchanged water were added to precipitate polyamideimide. It was immersed in methanol for 12 hours, collected by filtration, and washed with methanol. Subsequently, the precipitate was dried under reduced pressure at 100°C to obtain a polyamideimide resin (10). In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (10)]

Examples except that polyamide-imide resin (10) was used instead of polyamide-imide resin (1), and drying was performed at 200 ° C. for 30 minutes in the atmosphere instead of drying at 300 ° C. for 30 minutes in a nitrogen atmosphere. A polyamideimide film (10) having a film thickness of 50 µm was obtained in the same manner as in [Formation of polyamideimide film (1)] in 1. The weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (10) were measured according to the above measurement method, and Mw was 208,000, Tt was 91.8%, YI was 1.8, Tg was 373°C.

Example 8

[Preparation of polyamideimide resin (11)]

In a nitrogen gas atmosphere, 14.67 g (45.8 mmol) of TFMB and 233.3 g of DMAc were added to a 1 L separable flask equipped with a stirring blade, and TFMB was dissolved in DMAc with stirring at room temperature. Next, 4.283 g (13.8 mmol) of 4,4'-oxydiphthalic dianhydride (OPDA) was added to the flask, and the mixture was stirred at room temperature for 16.5 hours. After that, 1.359 g (4.61 mmol) of OBBC and 5.609 g (27.6 mmol) of TPC were added to the flask and stirred at room temperature for 1 hour. Next, 4.937 g (48.35 mmol) of acetic anhydride and 1.501 g (16.12 mmol) of 4-picoline were added to the flask, and after stirring at room temperature for 30 minutes, the temperature was raised to 70 ° C. using an oil bath, and further 3 hours. By stirring, a reaction solution was obtained.

After cooling the obtained reaction solution to room temperature, 360 g of methanol and 170 g of ion-exchanged water were added to precipitate polyamideimide. It was immersed in methanol for 12 hours, collected by filtration, and washed with methanol. Subsequently, the precipitate was dried under reduced pressure at 100°C to obtain a polyamideimide resin (11). In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (11)]

Polyamideimide having a film thickness of 50 μm was prepared in the same manner as in Example 7 [Film formation of polyamideimide film 10], except that polyamideimide resin 11 was used instead of polyamideimide resin 10. A film (11) was obtained. The weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film (11) were measured according to the above measurement method, and Mw was 259,000, Tt was 91.0%, YI was 1.9, Tg was 362°C.

Example 9

[Preparation of polyamideimide resin (12)]

6.140 g of 6FDA instead of 4.283 g of 4,4'-oxydiphthalic dianhydride (OPDA), 8.809 g (27.5 mmol) of TFMB instead of 14.67 g (45.8 mmol) of TFMB and 2,2'-dimethylbenzidine (MB ) Polyamide-imide resin (12) was obtained in the same manner as in Example 8 [Preparation of polyamide-imide resin (11)] except that 3.889 g (18.3 mmol) was used. In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film 12]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as [Formation of polyamide-imide film 11] in Example 8, except that polyamide-imide resin 12 was used instead of polyamide-imide resin 11. A film (12) was obtained. The weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film 12 were measured according to the above measurement method, and the Mw was 189,000, the Tt was 91.1%, and the Tg was 393°C. was

Example 10

[Preparation of polyamideimide resin (13)]

Except for using 3.670 g (18.3 mmol) of 4,4'-diaminodiphenyl ether (ODA) instead of 3.889 g of MB, in the same manner as in [Preparation of polyamideimide resin (12)] in Example 9, A polyamideimide resin (13) was obtained. In addition, the molar ratio of each component is shown in Table 1.

[Formation of polyamideimide film (13)]

A polyamide-imide film having a film thickness of 50 μm was prepared in the same manner as [Formation of polyamide-imide film 12] in Example 9, except that polyamide-imide resin 13 was used instead of polyamide-imide resin 12. A film (13) was obtained. The weight average molecular weight (Mw), total light transmittance Tt, yellowness YI, and glass transition temperature Tg of the polyamideimide film 13 were measured according to the above measurement method, and the Mw was 166,000, the Tt was 91.3%, and the Tg was 350°C. was

The molar ratio of each component in the above Examples and Comparative Examples is shown in Table 1 below.

About the obtained polyamide films (1)-(9), the elasticity modulus, surface hardness, and bending resistance were measured according to the said measuring method. The results are shown in Table 2.

From the above, it can be seen that the polyamideimide film (optical member) made of the polyamideimide resin related to the present invention has a low elastic modulus, excellent flexibility and high bending resistance. At the same time, it has been shown to have high surface hardness, and surface scratches can be suppressed.

Claims (10)

Equation (1) and Equation (2):
[Formula 1]

[In Formula (1) and Formula (2), X and Z each independently represent a divalent organic group,
Y represents a tetravalent organic group,
At least part of Z is Equation (3):
[Formula 2]

[In Formula (3), R ¹ to R ⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹ to R ⁸ are each Independently, it may be substituted with a halogen atom,
A represents -O-, -S-, -CO- or -NR ⁹ -, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom,
m is an integer from 1 to 4;
* represents a binding hand]
It is a constituent unit represented by]
A polyamideimide resin having a structural unit represented by and having a content rate of 3 mol% or more and 90 mol% or less of the structural unit represented by formula (3) with respect to the total of Y and Z. delete According to claim 1,
5 mol% or more and 100 mol% or less of Z is a polyamideimide resin represented by formula (3). According to claim 1,
A polyamideimide resin in which the ratio of the structural unit represented by Formula (3) to the total of the structural unit represented by Formula (1) and the structural unit represented by Formula (2) is 3 mol% or more and 90 mol% or less. According to claim 1,
The content rate of the structural unit represented by Formula (1) is 10 mol% or more and 90 mol% or less with respect to the total of the structural unit represented by Formula (1) and the structural unit represented by Formula (2), Polyamide-imide resin. According to claim 1,
At least part of X is in equation (4):
[Formula 3]

[In Formula (4), R ¹⁰ to R ¹⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁰ to R ¹⁷ are each Independently, it may be substituted with a halogen atom,
* represents a bonding hand]
Polyamide-imide resin, which is a structural unit represented by According to claim 1,
At least part of Y is expressed in equation (5):
[Formula 4]

[In Formula (5), R ¹⁸ to R ²⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the hydrogen atoms contained in R ¹⁸ to R ²⁵ are each Independently, it may be substituted with a halogen atom,
* represents a bonding hand]
Polyamide-imide resin, which is a structural unit represented by According to claim 1,
A polyamideimide resin having a glass transition temperature Tg calculated by tan δ in DMA measurement of less than 380°C. An optical member comprising the polyamide-imide resin according to any one of claims 1 and 3 to 8. An image display device provided with the optical member according to claim 9.