JP2023105599A - Polyamide-imide resin composition, polyamide-imide resin film, and method for controlling morphology of polyamide-imide resin composition - Google Patents

Abstract

To provide a polyamide-imide resin composition which controls compatibility, is colorless transparent, and is excellent in mechanical characteristics, and a film which is composed of the polyamide-imide resin composition.SOLUTION: A polyamide-imide resin composition contains a polyamide-imide resin having at least a structural unit derived from an acid dianhydride, a structural unit derived from a carboxylic acid compound, and a structural unit derived from diamine, wherein a ratio of a structural unit derived from a 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride to the whole structural unit derived from the acid dianhydride is more than 50 mol%, and a ratio of a structural unit derived from a carboxylic acid compound having an aromatic ring to the whole structural unit derived from the carboxylic acid compound is equal to or more than 50 mol%.SELECTED DRAWING: None

Description

The present invention relates to a polyamideimide resin composition and a polyamideimide resin film using the polyamideimide resin composition. The present invention also relates to a method of controlling the morphology of polyamideimide resin compositions.

2. Description of the Related Art Currently, image display devices such as liquid crystal display devices and organic EL display devices are widely used not only in televisions but also in various applications such as mobile phones and smart watches. With such expansion of applications, there is a demand for an image display device (flexible display) having a flexible characteristic. An image display device is composed of display elements such as a liquid crystal display element or an organic EL display element, and structural members such as a polarizing plate, a retardation plate, and a front plate. All these components need to be flexible in order to achieve a flexible display.

A thin display device is implemented in the form of a touch screen panel, and is used in various smart devices such as smart phones, tablet PCs, and various wearable devices. used for

A display device using such a touch screen panel is provided with a window cover including tempered glass or plastic film on the display panel to protect the display panel from scratches or external impacts. Transparency and hardness are required for the performance of window covers, and glass, which is an inorganic material, and polyimide resin film, which is an organic material, are mainly used as materials that satisfy these requirements.

Although glass has high transparency and can exhibit high hardness, it is not suitable for weight reduction and has the problem of being vulnerable to external impact. On the other hand, polyimide resin films are lightweight and tough against external impacts, but problems such as a decrease in transparency and a yellow coloration have been confirmed when the hardness is increased.

Polyamideimide resins are examples of resin compositions that solve these problems and have both mechanical properties such as high hardness and impact resistance and optical properties such as high transparency and colorlessness. Polyamide-imide resin, which has both properties of polyamide resin and polyimide resin, can produce a film that suppresses problems such as whitening in polyamide resin and coloring in polyimide resin, which appear when mechanical properties are improved.

As a production form of the polyamideimide resin as a raw material, a polyamideimide resin precursor containing a first block obtained by copolymerizing a tetracarboxylic dianhydride and a diamine and a second block obtained by copolymerizing a dicarboxylic acid compound and a diamine is prepared. Methods of production via are known.

As the composition of the polyamideimide resin, Patent Document 1 describes TFDB (2,2′-bistrifluoromethyl-4,4′-biphenyldiamine) as a diamine structural unit and 6FDA (a tetracarboxylic dianhydride structural unit). 4,4'-(Hexafluoroisopropylidene)diphthalic dianhydride) and TPC (tetrephthaloyl chloride; 1,4-benzenedicarbonyl chloride) as a dicarboxylic acid compound structural unit are copolymerized. , describes a copolymerized polyamideimide resin film.
Further, Patent Document 2 describes a copolymerized polyamideimide resin film further containing OBBC (4,4′-oxybis(benzoyl chloride)) as a dicarboxylic acid compound structural unit.

Japanese Patent Publication No. 2015-521686 JP 2018-119133 A

It is known that while films containing polyamide-imide resins have excellent performance, the performance varies greatly depending on the manufacturing method. This is because the inclusion of both the polyamide resin portion and the polyimide resin portion results in a wider range of possible higher-order structures than that of a single resin, which may lead to variations in quality.

The compatibility between the multiple blocks mentioned above contributes greatly to the widening of the range of higher-order structures, and controlling this compatibility enables the stable production of colorless, transparent, and excellent mechanical properties of polyamide-imide resin films. important in doing

An object of the present invention is to provide a colorless and transparent polyamide-imide resin composition with controlled compatibility and excellent mechanical properties, and a polyamide-imide resin film comprising this polyamide-imide resin composition.
Another object of the present invention is to provide a method for controlling the morphology of a polyamide-imide resin composition that is effective in realizing such a film.

As a result of intensive studies to solve the above problems, the present inventors have found that a polyamideimide resin has a structure derived from a carboxylic acid compound having a structural unit and an aromatic ring derived from a specific alicyclic tetracarboxylic dianhydride. By introducing the units in a predetermined ratio, the compatibility between the polyimide resin part of the first block and the polyamide resin part of the second block of the polyamide-imide resin, as well as the morphology that affects the mechanical and optical properties of the film can be controlled. As a result, the present inventors have found that it is possible to obtain a polyamide-imide resin composition that is colorless and transparent and has excellent mechanical properties, and a polyamide-imide resin film using this polyamide-imide resin composition, thereby completing the present invention.
That is, the gist of the present invention is as follows.

[1] A polyamideimide resin composition comprising a polyamideimide resin having at least a structural unit derived from an acid dianhydride, a structural unit derived from a carboxylic acid compound, and a structural unit derived from a diamine,
The proportion of structural units derived from 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride is more than 50 mol% with respect to the entire structural units derived from the acid dianhydride. and
A polyamide-imide resin composition, wherein the ratio of structural units derived from a carboxylic acid compound having an aromatic ring is 50 mol% or more with respect to the entire structural units derived from the carboxylic acid compound.

[2] 1,1′-bicyclohexane-3,3′,4,4′- relative to the total structural unit of the structural unit derived from the acid dianhydride and the structural unit derived from the carboxylic acid compound The polyamide-imide resin composition of [1], which contains 13 mol % or more and 30 mol % or less of structural units derived from tetracarboxylic dianhydride.

[3] Polyamideimide of [1] or [2] containing a structural unit derived from 3,3',4,4'-biphenyltetracarboxylic dianhydride as the structural unit derived from the acid dianhydride Resin composition.

[4] The polyamideimide resin composition according to any one of [1] to [3], which contains a structural unit derived from 1,4-benzenedicarbonyl chloride as the structural unit derived from the carboxylic acid compound.

[5] The polyamideimide resin of any one of [1] to [4] containing a structural unit derived from 2,2'-bistrifluoromethyl-4,4'-biphenyldiamine as the structural unit derived from the diamine Composition.

[6] A polyamideimide resin film obtained using the polyamideimide resin composition according to any one of [1] to [5].

[7] The polyamideimide resin film of [6], which has an exothermic peak area of 0.1 mJ/mg or more and 21.0 mJ/mg or less when measured by DSC.

[8] A method for controlling the morphology of a polyamideimide resin composition having at least a structural unit derived from an acid dianhydride, a structural unit derived from a carboxylic acid compound, and a structural unit derived from a diamine,
The ratio of structural units derived from 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride to the entire structural units derived from the acid dianhydride is 50 mol%. super and
50 mol% or more of structural units derived from a carboxylic acid compound having an aromatic ring relative to the entire structural units derived from the carboxylic acid compound;
A method for controlling the morphology of a polyamideimide resin composition, comprising controlling an exothermic peak area of 0.1 mJ/mg or more and 21.0 mJ/mg or less when a sample obtained by forming a film of the polyamideimide resin composition is measured by DSC.

According to the present invention, the compatibility between the polyimide resin part of the first block and the polyamide resin part of the second block of the polyamide-imide resin, and furthermore, the morphology that affects the mechanical properties and optical properties of the film can be controlled to obtain a colorless film. A polyamide-imide resin composition that is transparent and has excellent mechanical properties and a film made of this polyamide-imide resin composition can be realized.

Embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the invention.

[Polyamideimide resin composition]
The polyamideimide resin composition of the present invention includes a structural unit derived from an acid dianhydride (hereinafter sometimes referred to as "acid dianhydride unit"), a structural unit derived from a carboxylic acid compound (hereinafter referred to as "carboxylic Sometimes referred to as "acid compound unit".), a structural unit derived from diamine (hereinafter sometimes referred to as "diamine unit".) Polyamideimide resin having at least (hereinafter referred to as "polyamideimide resin in the present invention" A polyamideimide resin composition containing 1,1′-bicyclohexane-3,3′,4,4′- Tetracarboxylic dianhydride (hereinafter sometimes referred to as "H-BPDA".) Structural units derived from The ratio may be simply referred to as “H-BPDA unit ratio”) above 50 mol%, and the ratio of structural units derived from a carboxylic acid compound having an aromatic ring to the entire carboxylic acid compound units is 50 mol % or more.
That is, the polyamideimide resin in the present invention contained in the polyamideimide resin composition of the present invention is a first block of a polyimide resin portion in which an acid dianhydride and a diamine are copolymerized, and a carboxylic acid compound and a diamine are copolymerized. A polyamideimide resin containing a second block of a polyamide resin portion and a second block in the molecular structure, the first block contains a predetermined proportion of H-BPDA units having a rigid alicyclic structure, and the second By including a structural unit derived from a carboxylic acid compound having an aromatic ring in the block at a predetermined ratio, the proportion of monomers having an aromatic ring capable of interacting with the polyimide resin portion of the first block is changed, and the interaction is affected. It is possible to change the possible high-order structure between the polyimide resin portion of the second block and between the polyamide resin portions of the second block. As a result, the compatibility with the polyamide resin portion of the second block can be controlled, and a polyamide-imide resin composition that can easily obtain a suitable morphology that can achieve both mechanical properties and optical properties when processed into a film can be obtained. As a result, the film of the present invention which is colorless and transparent and has excellent mechanical properties can be obtained.

[Exothermic peak area by DSC measurement]
In DSC measurement, the exothermic peak area is originally observed as a negative value, but since the magnitude is important in the present invention, it is expressed as an absolute value after annotating exothermic.
In the polyamideimide resin film of the present invention produced by the method for producing a polyamideimide resin film of the present invention, the lower limit of the exothermic peak area in DSC (differential scanning calorimeter) measurement is preferably 0.1 mJ/mg or more, and 0.1 mJ/mg. 5 mJ/mg or more is more preferable, and 1.0 mJ/mg or more is even more preferable. Also, the upper limit is preferably 21.0 mJ/mg or less, more preferably 14.0 mJ/mg or less, and even more preferably 7.0 mJ/mg or less.
The range of the exothermic peak area is, for example, preferably 0.1 to 21.0 mJ/mg, more preferably 0.5 to 14.0 mJ/mg, still more preferably 1.0 to 7.0 mJ/mg. .

If the film has an exothermic peak area equal to or higher than the lower limit, when viewed as a resin, there is no risk that the crystal structure of the polyamide resin portion, which is a crystalline resin, will be damaged more than necessary, and it is transparent and has the expected mechanical properties. Characteristics, especially rigidity, tend to be exhibited. In addition, when viewed as a film, there is no possibility that the degree of crystallinity is increased more than necessary, and as a result, the transparency and flexibility of the film tend to be obtained.
On the other hand, in a film having an exothermic peak equal to or lower than the above upper limit, when viewed as a resin, the compatibility between the polyamide resin portion and the polyimide resin portion, which are crystalline resins, is sufficient, and the degree of crystallinity increases more than necessary. It tends to be safe and suitable for optical applications. When viewed as a film, the degree of crystallinity is reached to ensure mechanical strength, and as a result, the rigidity of the film tends to be exhibited.
A film having an exothermic peak area within the above range can be expected to achieve a balance between the crystallinity of the polyamide resin portion and the compatibility between the polyamide resin portion and the polyimide resin portion, that is, to achieve both mechanical properties and optical properties. As for the film, it can be expected that the film-forming conditions are suitable for securing an appropriate degree of crystallinity.

In order to obtain a polyamide-imide resin having moderate crystallinity and compatibility, for example, for a polyamide resin part composed mainly of structural units derived from a compound having an aromatic ring, the polyimide resin part has an aliphatic ring (hereinafter referred to as an alicyclic), and the ratio of structural units derived from a compound having an aromatic ring may be adjusted. Also, in order to obtain a film having an appropriate degree of crystallinity, the heating conditions at the time of film production may be adjusted, for example, to a temperature range that is involved in the growth of crystals.
The exothermic peak area in the DSC measurement of the polyamide-imide resin film of the present invention can be determined by the method described in the Examples section below.

[Polyamideimide resin]
<Acid dianhydride unit>
The polyamideimide resin of the present invention is characterized by containing more than 50 mol % of H-BPDA units relative to the total acid dianhydride units, that is, having a proportion of more than 50 mol % of H-BPDA units.
The H-BPDA unit ratio is preferably 66 mol % or more, more preferably 75 mol % or more, from the viewpoint of obtaining high transparency and colorlessness in the film while ensuring appropriate crystallinity and compatibility.

The polyamideimide resin in the present invention may contain an acid dianhydride unit other than the H-BPDA unit as the acid dianhydride unit, and the acid dianhydride constituting the other acid dianhydride unit includes aromatic and aliphatic tetracarboxylic dianhydrides other than H-BPDA. These compounds may be used individually by 1 type, or may be used in arbitrary ratios and combinations of 2 or more types.

The aromatic tetracarboxylic dianhydrides include tetracarboxylic dianhydrides having one aromatic ring contained in the molecule, tetracarboxylic dianhydrides having two or more independent aromatic rings in the molecule, Examples include tetracarboxylic dianhydrides having condensed aromatic rings in the molecule and aromatic tetracarboxylic dianhydrides having fluorine atoms in the molecule.

Examples of aliphatic tetracarboxylic dianhydrides include chain aliphatic tetracarboxylic dianhydrides and cyclic aliphatic tetracarboxylic dianhydrides (alicyclic tetracarboxylic dianhydrides).

When designing a resin with high mechanical properties, among tetracarboxylic dianhydrides, those with a rigid structure with little bending are preferred. A tetracarboxylic dianhydride having one ring, a tetracarboxylic dianhydride having two or more independent aromatic rings in the molecule, and an alicyclic tetracarboxylic dianhydride are preferably used.

<Aromatic tetracarboxylic dianhydride>
(Tetracarboxylic dianhydride with one aromatic ring contained in the molecule)
Examples of the tetracarboxylic dianhydride having one aromatic ring in the molecule include pyromellitic dianhydride and 1,2,3,4-benzenetetracarboxylic dianhydride. Among these, pyromellitic dianhydride is particularly preferred from the viewpoint of improving crack resistance, handleability, heat resistance and flexibility of the glass film laminate.

(Tetracarboxylic dianhydride having two or more independent aromatic rings)
Tetracarboxylic dianhydrides having two or more independent aromatic rings include, for example, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',6,6'-biphenyl Tetracarboxylic dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl) ) methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 3,3′,4 ,4′-diphenylsulfonetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, bis(2,3-dicarboxyphenyl)ether dianhydride, 3,3′,4, 4'-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 4,4-oxydiphthalic dianhydride, 4,4-(p-phenylenedioxy) diphthalic dianhydride, 4,4-(m-phenylenedioxy)diphthalic dianhydride, and the like.

Among these, tetracarboxylic dianhydrides having two independent aromatic rings are preferable, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 2,2',3,3'-benzophenone Tetracarboxylic dianhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride are particularly preferred from the viewpoint of improving handling properties and heat resistance.

(Tetracarboxylic dianhydride having condensed aromatic ring)
Examples of the tetracarboxylic dianhydride having a condensed aromatic ring include 1,2,5,6-naphthalenedicarboxylic dianhydride, 1,4,5,8-naphthalenedicarboxylic dianhydride, 2,3, 6,7-naphthalenedicarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8 -phenanthrenetetracarboxylic dianhydride and the like.

(Aromatic tetracarboxylic dianhydride having a fluorine atom)
Examples of fluorine atom-containing aromatic tetracarboxylic dianhydrides include 4,4′-(hexafluoroisopropylidene)diphthalic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)- 1,1,1,3,3,3-hexafluoropropane dianhydride, 1,4-difluoropyromellitic dianhydride, 1,4-ditrifluoromethylpyromellitic dianhydride and the like.

<Aliphatic tetracarboxylic dianhydride>
(chain aliphatic tetracarboxylic dianhydride)
Chain aliphatic tetracarboxylic dianhydrides include, for example, ethylenetetracarboxylic dianhydride, butanetetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic dianhydride, and the like. is mentioned.

(Alicyclic tetracarboxylic dianhydride)
Alicyclic tetracarboxylic dianhydrides other than H-BPDA include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride. product, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclohexanetetracarboxylic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)- 1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, tricyclo[6.4.0.02,7]dodecane-1,8,2,7-tetra Carboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.1]heptane-2,3,5 , 6-tetracarboxylic dianhydride and the like.

<Suitable other acid dianhydride units>
Among the above-described acid dianhydrides constituting acid dianhydride units other than H-BPDA units, the present invention particularly provides 3,3′,4,4′-biphenyltetracarboxylic dianhydride (hereinafter referred to as From the viewpoint of improving physical properties such as mechanical properties and heat resistance, Preferably, when H-BPDA units and BPDA units are included as acid dianhydride units, 0 to 50 mol %, particularly 0 to 34 mol % of BPDA units are preferably included in the total of these. If the content of the BPDA unit is equal to or less than the above upper limit, the effect of the present invention by containing the H-BPDA unit can be obtained more effectively, and if it is equal to or more than the above lower limit, the above effect by containing the BPDA unit can be more effectively obtained. can be effectively obtained.
Further, in the polyamide-imide resin of the present invention, in order to exhibit the effects of H-BPDA and BPDA, the total content of H-BPDA units and BPDA units in all dianhydride units is 50 mol% or more. preferably 66 mol % or more, particularly preferably 75 mol % or more.
This is because the polyamide resin part according to the present invention has a more rigid structure than the polyimide resin part and has high mechanical properties. It is the result of adjusting as much as possible, and it can be freely changed according to the type and use of the compound unit.

Further, from the viewpoint of suppressing yellowing while maintaining mechanical properties, a structural unit derived from 4,4'-(hexafluoroisopropylidene diphthalic dianhydride) (hereinafter sometimes referred to as "6FDA") (hereinafter sometimes referred to as "6 FDA units").
The polyamideimide resin in the present invention contains H-BPDA, which is an alicyclic ring, to control the balance between crystallinity and compatibility, so the content of 6FDA units in the acid dianhydride units is 25 mol%. The following is preferable from the viewpoint of controlling the compatibility with the polyamide resin portion within a suitable range.

<Carboxylic acid compound unit>
The polyamide-imide resin in the present invention essentially has a structural unit derived from a carboxylic acid compound having an aromatic ring as a carboxylic acid compound unit.
Examples of the carboxylic acid compound constituting the carboxylic acid compound unit include compounds represented by the following formula (1). These compounds may be used individually by 1 type, or may be used in arbitrary ratios and combinations of 2 or more types.

(In Formula (1), W represents a divalent organic group, and X ¹ and X ² each independently represent OH or a halogen atom, preferably a chlorine atom.)

W in formula (1) represents a divalent 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. The divalent organic group includes groups represented by the following formulas (1a) and (1b); or a group substituted with a trifluoromethyl group; and a divalent chain hydrocarbon group having 6 or less carbon atoms.

(In formulas (1a) and (1b), * represents a bond,
Q 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—, preferably a single bond, —O—, or —Ar—O—Ar—. Ar represents an arylene group having 6 to 20 carbon atoms in which a hydrogen atom may be substituted with a fluorine atom, and specific examples thereof include a phenylene group. )

Specific examples of the carboxylic acid compound represented by formula (1) include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, acid chloride compounds thereof, acid anhydrides, and the like.
Specific examples include terephthalic acid; isophthalic acid; naphthalenedicarboxylic acid; 4,4′-biphenyldicarboxylic acid; 3,3′-biphenyldicarboxylic acid; benzoic acid is a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -SO ₂ -, -O-, -S-, -NR-, -C(= O)- or phenylene group-linked compounds; and acid chloride compounds thereof. Here, R represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom.

The carboxylic acid compound represented by formula (1) preferably contains at least one selected from terephthalic acid, 4,4'-biphenyldicarboxylic acid, 4,4'-oxybisbenzoic acid, and acid chloride compounds thereof. More preferably, 1,4-benzenedicarbonyl chloride (hereinafter sometimes referred to as "TPC") and/or 4,4'-biphenyldicarbonyl chloride is more preferably included, particularly TPC. is preferable from the viewpoint of compatibility with the polyimide resin portion.

Polyamideimide resin in the present invention, as a carboxylic acid compound unit, has a structural unit derived from a carboxylic acid compound having an aromatic ring, as the carboxylic acid compound having an aromatic ring, for example, terephthalic acid, 4,4'- Biphenyldicarboxylic acid, 4,4'-oxybisbenzoic acid, and their acid chloride compounds, preferably TPC, 4,4'-biphenyldicarbonyl chloride, from the viewpoint of compatibility with the polyimide resin portion, TPC more preferred.

The polyamideimide resin in the present invention contains 50 mol% or more structural units derived from a carboxylic acid compound having an aromatic ring with respect to the entire carboxylic acid compound unit as a carboxylic acid compound unit, and from the viewpoint of compatibility with the polyimide resin portion, 60 mol%. It is preferable to contain at least 70 to 100 mol %, and it is particularly preferable that all the carboxylic acid compound units are structural units derived from a carboxylic acid compound having an aromatic ring.

<Diamine unit>
Examples of the diamine compound that constitutes the diamine unit contained in the polyamide-imide resin in the present invention include aromatic diamine compounds and aliphatic diamine compounds. These compounds may be used individually by 1 type, or may be used in arbitrary ratios and combinations of 2 or more types.

Examples of aromatic diamine compounds include diamine compounds having one aromatic ring in the molecule, diamine compounds having two or more independent aromatic rings, diamine compounds having condensed aromatic rings, and aromatic diamines having a fluorine atom. compounds, siloxane-based aromatic diamine compounds, and the like.
Examples of the aliphatic diamine compound include linear aliphatic diamine compounds, cycloaliphatic diamine compounds (alicyclic diamine compounds), siloxane-based aliphatic diamine compounds, and the like.

Among diamine compounds, when designing resins with high mechanical properties similar to acid dianhydrides, those with aromatic rings having a rigid skeleton are preferred. Those having a polar group are preferable in terms of suppressing change, and from the viewpoint of improving handleability and heat resistance, diamine compounds containing one aromatic ring in the molecule, two or more independent rings in the molecule It is preferable to use a diamine compound having an aromatic ring, an aromatic diamine compound having a fluorine atom, a siloxane-based aromatic diamine compound, and a siloxane-based aliphatic diamine compound.

<Aromatic diamine compound>
(Diamine compound having one aromatic ring)
Diamine compounds having one aromatic ring include, for example, 1,4-phenylenediamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 3-aminobenzylamine, 2,5-dimethyl-1,4 -phenylenediamine, p-xylylenediamine, m-xylylenediamine, 2,3,5,6-tetramethyl-1,4-phenylenediamine and the like.
Among these, 1,4-phenylenediamine and 2,5-dimethyl-1,4-phenylenediamine are particularly preferred from the viewpoint of improving handling properties, heat resistance and flexibility.

(Diamine compound having two or more independent aromatic rings)
Diamine compounds having two or more independent aromatic rings include, for example, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4 '-diamino-3,3'-dihydroxybiphenyl, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,3-bis(4-aminophenoxy)neopentane, bis(4-amino-3-carboxy phenyl)methane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, N-(4-aminophenoxy)-4-aminobenzamide, 2,7-diaminofluorene, 1,1-bis(4 -aminophenyl)cyclohexane, 3,3'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 3,3' -diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-ethylenedianiline, 4,4'-methylenebis(2,6-diethylaniline), 4,4'-methylenebis (2-ethyl-6-methylaniline), 4,4′-diamino-2,2′-dimethoxybiphenyl, 2,3′-diaminodiphenyl ether, bis(4-aminophenoxy)methane, 1,3′-bis( 4-aminophenoxy)propane, 1,4'-bis(4-aminophenoxy)butane, 1,5'-bis(4-aminophenoxy)pentane, 2,2-bis(3-amino-4-hydroxyphenyl) Diamine compounds having two independent aromatic rings such as propane, bis(3-amino-4-hydroxyphenyl)sulfone, N,N-bis(4-aminophenyl)piperazine; 1,4-bis(4-aminophenoxy) ) benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)-2,5-di-t-butylbenzene, 1,4-bis(4-aminophenoxy) -2,3,5-trimethylbenzene, N,N-bis(4-aminophenyl)terephthalamide, 1,3-bis(3-aminophenoxy)benzene, α,α'-bis(4-aminophenyl)- Diamine compounds having three independent aromatic rings such as 1,4-diisopropylbenzene, 1,3-bis[1-(4-aminophenyl)-1-methylethyl]benzene; 2,2-bis(4-( 4-aminophenoxy)phenyl)propane, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, 4,4′-bis(4-aminophenoxy)biphenyl , 4,4′-(9-fluorenylidene)dianiline, 4,4′-(biphenyl-2,5-diylbisoxy)bisaniline, 4,4′-bis(4-aminobenzamido)-3,3′-dihydroxy Diamine compounds having four independent aromatic rings such as biphenyl, 4,4'-bis(4-aminophenoxy)benzophenone, and the like.

Among these, those having 2 or more and 4 or less independent aromatic rings are preferable. In particular, 4,4′-diamino-2,2′-dimethylbiphenyl, 4,4′-diaminodiphenyl ether, N-(4-aminophenoxy)-4-aminobenzamide, 1,5′-bis(4-aminophenoxy ) pentane, 3,3′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfone, bis(4-(4-aminophenoxy)phenyl) sulfone and 2,2-bis(4-(4-aminophenoxy)phenyl ) Propane is particularly preferred from the viewpoint of improving handleability, heat resistance, flexibility and colorless transparency.

(Diamine compound having condensed aromatic ring)
Examples of the diamine compound having a condensed aromatic ring include 2-(4-aminophenyl)-6-aminobenzoxazole, 2-(4-aminophenyl)-5-aminobenzoxazole, 5-amino-2-(4 -aminophenyl)-1H-benzimidazole, 1,5-diaminonaphthalene, 3,7-diamino-2,8-dimethyldibenzothiophene 5,5-dioxide and the like.

Among these, 2-(4-aminophenyl)-6-aminobenzoxazole, 2-(4-aminophenyl)-5-aminobenzoxazole, 5-amino-2-(4-aminophenyl)-1H-benzoxazole Imidazole is particularly preferred from the viewpoint of improving handleability, heat resistance, flexibility and colorless transparency.

(Aromatic diamine compound having fluorine atom)
Examples of aromatic diamine compounds having fluorine atoms include 5-trifluoromethyl-1,3-benzenediamine, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (2,2'-bistrifluoromethyl-4,4'-biphenyldiamine),4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl ether, 2,2'-bis(4-aminophenyl)hexafluoropropane , 2,2′-bis(3-aminophenyl)hexafluoropropane, 4,4′-diaminooctafluorobiphenyl, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2- Bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 4,4'-diamino-2-(trifluoromethyl)diphenyl ether, 1,4-bis{4-amino-2-(trifluoromethyl)phenoxy} Benzene, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane, 2,2-bis[4-{4-amino-2-(trifluoromethyl)phenoxy}phenyl]hexafluoropropane, etc. is mentioned.
Among these, 2,2'-bistrifluoromethyl-4,4'-biphenyldiamine (hereinafter sometimes referred to as "TFDB") and 2,2-bis(4-(4-aminophenoxy)phenyl) Hexafluoropropane is particularly preferred from the viewpoint of improving handleability, heat resistance, flexibility and colorless transparency.

(Siloxane-based aromatic diamine compound)
The siloxane-based aromatic diamine compound includes main chain phenyl type and side chain phenyl type. Main chain phenyl types include, for example, bis(4-aminophenoxy)dimethylsilane, 1,3-bis(4-aminophenoxy)-1,1,3,3-tetramethyldisiloxane, α,ω-bis( 4-aminophenyl) polydimethylsiloxane, α, ω-bis (4-amino-3-methylphenyl) polydimethylsiloxane, Shin-Etsu Chemical Co., Ltd. both terminal amino-modified silicone (PAM-E, KF-8010, X-22- 161A, X-22-161B, KF-8012, KF-8008), both terminal amino-modified silicone manufactured by Dow Corning Toray (BY16-871, BY16-835U), both terminal amino-modified silicone manufactured by Momentive (XF42-C5379) etc. Examples of the side chain phenyl type include α,ω-bis(3-aminopropyl)polydiphenylsiloxane, both terminal amino-modified silicone (X-22-1660B-3, X-22-9409) manufactured by Shin-Etsu Chemical Co., Ltd., and the like. mentioned.

<Aliphatic diamine compound>
(Chain aliphatic diamine compound)
Chain aliphatic diamine compounds include, for example, 1,2-ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-hexamethylenediamine, 1,5 -diaminopentane, 1,10-diaminodecane, 1,2-diamino-2-methylpropane, 2,3-diamino-2,3-butanediamine, 2-methyl-1,5-diaminopentane and the like.

(Alicyclic diamine compound)
Examples of alicyclic diamine compounds include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4′-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine) and the like.

Among these, 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine) are particularly preferred from the viewpoint of improving handling properties, heat resistance, flexibility and colorless transparency.

(Siloxane-based aliphatic diamine compound)
Examples of siloxane-based aliphatic diamine compounds include 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, 1,3-bis(3-aminobutyl)-1, 1,3,3-tetramethyldisiloxane, 1,3-bis(4-aminobutyl)-1,1,3,3-tetramethyldisiloxane, α,ω-bis(2-aminoethyl)polydimethylsiloxane , α,ω-bis(3-aminopropyl)polydimethylsiloxane, α,ω-bis(4-aminobutyl)polydimethylsiloxane, and the like.

Among these, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is particularly preferred from the viewpoint of improving handling properties, heat resistance, flexibility and colorless transparency.

In particular, the polyamide-imide resin in the present invention contains a structural unit derived from TFDB as a diamine unit (hereinafter sometimes referred to as "TFDB unit"). It is preferable from the viewpoint of productivity to ensure the reactivity that can be obtained, and from the viewpoint of the composition to ensure the aromatic polyamide resin part and the polyimide resin part to ensure mechanical properties, and the TFDB unit is preferable with respect to all the diamine units. It preferably contains 50 mol % or more, particularly 70 mol % or more, especially 80 to 100 mol %.

<Content ratio of each structural unit>
In the polyamideimide resin in the present invention, the lower limit of the ratio of H-BPDA units to the total of acid dianhydride units and carboxylic acid compound units is preferably 1 mol% or more, more preferably 5 mol% or more, and 13 mol% or more. More preferred. Moreover, the upper limit is preferably 50 mol % or less, more preferably 40 mol % or less, and even more preferably 30 mol % or less.
The range of the H-BPDA unit is, for example, preferably 1 to 50 mol%, more preferably 5 to 40 mol%, still more preferably 13 to 30 mol%.
If it is at least the above lower limit, there is a tendency that the effect of the present invention by introducing the H-BPDA unit can be sufficiently obtained. Further, when the content is equal to or less than the above upper limit, there is a tendency that performance such as mechanical properties and heat resistance of the film can be secured.

The polyamideimide resin in the present invention preferably contains 50 mol% or more carboxylic acid compound units, more preferably 60 mol% or more, and 70 mol% or more with respect to the total of acid dianhydride units and carboxylic acid compound units. More preferably, it contains If the ratio of the carboxylic acid compound units is at least the above lower limit, high mechanical properties and heat resistance derived from the polyamide resin portion can be exhibited. On the other hand, the content of carboxylic acid compound units is preferably 99 mol% or less, more preferably 90 mol% or less, and even more preferably 75 mol% or less, relative to the total of acid dianhydride units and carboxylic acid compound units. If the ratio of the carboxylic acid compound unit is equal to or less than the above upper limit, deterioration of optical properties due to whitening caused by crystallization of the polyamide resin portion can be suppressed.

In addition, the sum of the acid dianhydride units and the carboxylic acid compound units and the diamine units is usually 1:1 in molar ratio.

[Method for producing polyamideimide resin]
The method for producing the polyamideimide resin in the present invention is not particularly limited, but for example,
(1) a diamine compound constituting the aforementioned diamine unit, an acid dianhydride comprising H-BPDA constituting the aforementioned acid dianhydride unit as an essential component, and a carboxylic acid compound constituting the aforementioned carboxylic acid compound unit in a solvent to obtain a polyamideimide resin precursor, and
(2) It can be produced by a method including at least a step of imidizing (dehydration ring-opening) a polyamide-imide resin precursor.

In step (1), first, an acid dianhydride and a diamine compound are used to produce a first block, which is a polyimide resin portion, and then the carboxylic acid compound and the diamine compound are produced in the same reaction system. is used to form the second block, which is the polyamide resin portion, to obtain a polyamideimide resin precursor containing the first block and the second block in the molecular structure.

The reaction for forming the first block and the second block is preferably solution polymerization using a solvent.
The solvent is not particularly limited as long as it is a known reaction solvent, but preferably m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide ( DMSO), acetone, ethyl acetate, etc., can be used. Alternatively, low boiling point solutions such as tetrahydrofuran (THF), chloroform, or low absorption solvents such as γ-butyrolactone can be used.

The amount of the solvent used is not particularly limited, but in order to obtain an appropriate polyamideimide resin precursor solution, the amount of the solvent used is preferably 50 to 95% by mass of the polyamideimide resin precursor solution, and 70 to 90% by mass. is more preferable.

The polymerization reaction conditions for producing the polyamideimide resin precursor are not particularly limited, but the polymerization reaction is preferably carried out at -10 to 80°C for 2 to 48 hours in an inert gas atmosphere such as nitrogen or argon.

In step (2), a dehydrating agent and an imidization catalyst are added to the polyamide-imide resin precursor solution obtained in step (1), and the mixture is heated at a temperature of 70 to 120°C. In this step, the imidization of the polyamide-imide resin precursor proceeds. The heating time in this step may be appropriately selected according to the scale of the reaction and the type and amount of reagents used, but is usually 1 to 48 hours.

The dehydrating agent used in step (2) is a substance capable of promoting polycondensation reactions involving dehydration. Examples of dehydrating agents include acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride and isovaleric anhydride. The dehydrating agent is preferably selected from the group consisting of acetic anhydride and propionic anhydride, more preferably acetic anhydride.

Examples of imidization catalysts include aliphatic amines such as tripropylamine, dibutylpropylamine, ethyldibutylamine; N-ethylpiperidine, N-propylpiperidine, N-butylpyrrolidine, N-butylpiperidine, and N-propylhexahydro Alicyclic amines (monocyclic) such as azepine; azabicyclo[2.2.1]heptane, azabicyclo[3.2.1]octane, azabicyclo[2.2.2]octane, and azabicyclo[3.2. 2] Alicyclic amines (polycyclic) such as nonane; Tertiary ball amines such as aromatic amines such as 4-dimethylpyridine, 2,4,6-trimethylpyridine, 3,4-cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline, and isoquinoline .
Among these, triethylamine, tripropylamine, N-ethylpiperidine, N-propylpiperidine, pyridine, methylpyridine, ethylpyridine, dimethylpyridine and isoquinoline are preferred.

[Other ingredients]
The polyamideimide resin composition of the present invention may contain components other than the polyamideimide resin of the present invention.

For example, the polyamideimide resin composition of the present invention may contain an additive having a light absorbing function in addition to the polyamideimide resin of the present invention from the viewpoint of improving the visibility and quality of the resulting film. Additives having a light absorption function include, for example, ultraviolet absorbers, bluing agents, and the like. The additive having a light absorption function is preferably selected from the group consisting of ultraviolet absorbers and bluing agents, since this facilitates improving the visibility and quality of the film of the present invention. The polyamide-imide resin composition of the present invention may contain one type of additive having a light absorbing function, or may contain two or more types of additives having a light absorbing function.

As the ultraviolet absorber, it may be used by appropriately selecting from those commonly used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may contain a compound that absorbs light with 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. When the polyamide-imide resin composition of the present invention contains an ultraviolet absorber, deterioration of the polyamide-imide resin is suppressed, so that the visibility of the film can be enhanced. In addition, in this specification, a "system compound" refers to the derivative of the compound to which the said "system compound" is attached. For example, a "benzophenone-based compound" refers to a compound having benzophenone as a parent skeleton and a substituent attached to the benzophenone.

When the polyamideimide resin composition of the present invention contains an ultraviolet absorber, the amount of the ultraviolet absorber to be added may be appropriately selected depending on the type of ultraviolet absorber used. Based on the total mass of solids excluding, preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 3% by mass or more, preferably 10% by mass or less, more preferably 8% by mass or less, More preferably, it is 6% by mass or less. A suitable addition amount varies depending on the ultraviolet absorber used, but adjusting the addition amount so that the transmittance of light at 400 nm is about 20 to 60% makes it easy to increase the light resistance of the film of the present invention, and transparency. It is preferable because it is easy to obtain a film having a high

The bluing agent may be appropriately selected from those commonly used as bluing agents in the field of resin materials. A bluing agent is an additive (dye, pigment) that absorbs light in a wavelength region such as orange to yellow in the visible light region and adjusts the hue. inorganic dyes and pigments, and organic dyes and pigments such as phthalocyanine bluing agents and condensed polycyclic bluing agents. The bluing agent is not particularly limited, but from the viewpoint of heat resistance, light resistance and solubility, a condensed polycyclic bluing agent is preferable, and an anthraquinone bluing agent is more preferable. From the viewpoint of heat resistance, the bluing agent preferably has a thermal decomposition temperature of 200°C or higher. Examples of condensed polycyclic bluing agents include anthraquinone bluing agents, indigo bluing agents, and phthalocyanine bluing agents.

When the polyamideimide resin composition of the present invention contains a bluing agent, the addition amount of the bluing agent may be appropriately selected depending on the type of bluing agent used. Based on the total mass of solids excluding, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, still more preferably 0.03% by mass or more, preferably 1.0% by mass or less, It is more preferably 0.5% by mass or less, still more preferably 0.2% by mass or less.

The polyamideimide resin composition of the present invention may further contain an inorganic material such as inorganic particles in addition to the polyamideimide resin of the present invention. Examples of inorganic materials 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 polyamide-imide varnish, the inorganic material is preferably inorganic particles, particularly silica particles. The inorganic particles may be bonded together by molecules having siloxane bonds.

The average primary particle size of the inorganic particles is preferably 10 to 100 nm, more preferably 20 to 80 nm, from the viewpoints of film transparency, mechanical properties, and inhibition of aggregation of the inorganic particles. Here, the average primary particle diameter can be determined by measuring 10 directional diameters with a transmission electron microscope (TEM) and calculating their average value.

When the polyamideimide resin composition of the present invention contains an inorganic material, the content of the inorganic material in the polyamideimide resin composition is preferably 0 based on the total mass of the solid content excluding the solvent of the polyamideimide resin composition. ~90% by mass, more preferably 0 to 60% by mass, still more preferably 0 to 40% by mass. 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 film.

The polyamideimide resin composition of the present invention may contain other additives. Other additives include, for example, antioxidants, release agents, stabilizers, flame retardants, pH adjusters, silica dispersants, lubricants, thickeners and leveling agents. When the polyamideimide resin composition of the present invention contains other additives, the content of the other additives is preferably 0 based on the mass of the solid content excluding the solvent of the polyamideimide resin composition of the present invention. % by mass or more and 20% by mass or less, more preferably 0% by mass or more and 10% by mass or less.

Including the case where the polyamideimide resin composition of the present invention contains other components as described above, based on the total mass of the solid content excluding the solvent of the polyamideimide resin composition of the present invention, the polyamideimide resin in the present invention is preferably contained in an amount of 40% by mass or more from the viewpoint of ensuring the flexibility derived from the resin.

Also, the polyamide-imide resin composition of the present invention is used as a polyimide varnish containing a solvent, which will be described later, for the production of the film of the present invention.

〔the film〕
The film of the present invention produced using the polyamide-imide resin composition of the present invention is described below.

[Film manufacturing method]
In order to produce the film of the present invention using the polyamideimide resin composition of the present invention, first, a polyamideimide resin composition containing the polyamideimide resin of the present invention and other optional components and a solvent ( Hereinafter, it may be referred to as “polyamideimide varnish”.), and using this polyamideimide varnish, the following steps (3) and (4) can be performed.

Polyamideimide varnish may be produced by adding a solvent and optionally other components to the solution containing the polyamideimide resin obtained in the above steps (1) and (2) and stirring. Then, a poor solvent is added to the solution containing the polyamideimide resin obtained in steps (1) and (2) to precipitate the polyamideimide resin by a reprecipitation method, dried and taken out as a precipitate, and the taken out polyamideimide resin precipitate. It may be manufactured by dissolving the substance in a solvent.

As the solvent used for the polyamideimide varnish, the same solvent as that used in the polymerization of the polyamideimide resin precursor solution can be used. As the poor solvent, one or more selected from solvents having a lower polarity than this solvent, that is, water, alcohols, ethers and ketones can be used. The amount of the poor solvent used is not particularly limited, but it is preferably 5 to 20 times the mass of the polyamideimide resin solution.

The film of the present invention is, for example, (3) a step of applying the polyamideimide varnish obtained as described above to a support, and
(4) A step of obtaining a film by the following (4-1) or (4-2) (4-1) A step of peeling off the coating film of the composition from the support after drying, or
(4-2) It can be produced through a step of drying a coating film of the composition and then peeling it from a support, and a step of heating the peeled film.

For example, by a known roll-to-roll or batch method, a coating film of polyamideimide varnish is formed by applying polyamideimide varnish on a support such as a resin substrate, SUS belt, or glass substrate. can be done. Examples of the support include PET film, PEN film, polyimide resin film, polyamideimide resin film, SUS belt, and glass substrate. Among them, PET films, polyimide resin films, SUS belts, and glass substrates are preferable because of their ease of handling. From the viewpoints of adhesion with the film of the present invention and cost, a PET film is more preferable in roll-to-roll, and a glass substrate is more preferable in batch method.

Next, in step (4-1) or step (4-2), the coating film of polyamide-imide varnish is dried and peeled off from the support after drying. Drying of the coating film can be carried out at a temperature of preferably 150 to 400°C, more preferably 200 to 350°C. Drying of the coating may be carried out under conditions of an inert atmosphere or reduced pressure, if desired. The film of the present invention can be obtained by peeling the coating from the support after drying. In addition, as described in step (4-2), for example, a step of further heating the peeled film may be performed for the purpose of further increasing the surface hardness of the film of the present invention. The heating temperature is preferably below the glass transition point.

At least one surface of the film produced as described above may be subjected to a surface treatment step. Surface treatments include, for example, UV ozone treatment, plasma treatment, and corona discharge treatment.

[Film thickness]
The thickness of the film of the present invention varies depending on its use, but is usually 5 to 200 μm, preferably 10 to 100 μm, more preferably 30 to 70 μm. If the thickness of the film is at least the above lower limit, durability required for use as a cover film can be ensured, and if the thickness is below the above upper limit, flexibility at the time of bending can be ensured.

[Other layers]
The film of the present invention may further have a functional layer laminated thereon. Examples of functional layers include layers having various functions such as a hard coat layer, an ultraviolet absorbing layer, an adhesive layer, a refractive index adjusting layer, and a primer layer. The films of the invention may comprise one or more functional layers. Also, one functional layer may have multiple functions.

The hard coat layer is preferably arranged on the viewer side surface of the film. The hard coat layer may have a single layer structure or a multilayer structure. The hard coat layer comprises a hard coat layer resin. Examples of the hard coat layer resin include acrylic resins, epoxy resins, urethane resins, benzyl chloride resins, vinyl resins, silicone resins, or mixtures thereof. UV curable, electron beam curable, or thermosetting resins such as resins may be used. In particular, the hard coat layer preferably contains an acrylic resin from the viewpoint of mechanical properties such as surface hardness and from an industrial point of view. In a preferred embodiment of the present invention, since the film of the present invention has a high surface hardness, it has sufficient surface hardness to be used in image display devices and the like even without a hard coat layer. Therefore, when the film of the present invention further has a hard coat layer, it is possible to further increase the surface hardness of the film.

The ultraviolet absorbing layer is a layer having a function of absorbing ultraviolet rays. It is composed of dispersed ultraviolet absorbers. By providing an ultraviolet absorbing layer as a functional layer, it is possible to easily suppress a change in yellowness due to light irradiation.

The adhesive layer is a layer having an adhesive function, and has a function of adhering the film of the present invention to another member. Commonly known materials can be used as the material for forming the adhesive layer. 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 that constitutes the adhesive layer after the film is adhered to another member. The adhesive strength between the film of the present invention and the adhesive layer is 0.1 N/cm or more, preferably 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 afterward.

The adhesive layer may be a layer composed of an adhesive called Pressure Sensitive Adhesive (PSA), which is adhered to an object by pressing. The pressure-sensitive adhesive may be a pressure-sensitive adhesive that is "a substance that has adhesiveness at room temperature and adheres to the adherend with light pressure" (JIS K6800), and "a specific component is a protective coating (microcapsule) It may be a capsule-type adhesive that is "adhesive that can maintain stability until the coating is destroyed by appropriate means (pressure, heat, etc.)" (JIS K6800).

The hue-adjusting layer is a layer having a hue-adjusting function and capable of adjusting the hue of the film of the present invention to a desired hue. A hue adjustment 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, red iron oxide, titanium oxide-based calcined pigments, ultramarine blue, cobalt aluminate, and carbon black; azo-based compounds, quinacridone-based compounds, anthraquinone-based compounds, Organic pigments such as perylene compounds, isoindolinone compounds, phthalocyanine compounds, quinophthalone compounds, threne compounds, and diketopyrrolopyrrole compounds; extender pigments such as barium sulfate and calcium carbonate; and basic dyes, Dyes such as acid dyes and mordant dyes can be mentioned.

The refractive index adjusting layer is a layer having a function of adjusting the refractive index, has a different refractive index from the layer containing the polyamideimide resin A in the film of the present invention, and imparts a predetermined refractive index to the film of the present invention. It is a layer that can The refractive index adjusting layer may be, for example, a resin layer containing an appropriately selected resin and optionally a pigment, or may be a metal thin film.

Pigments that adjust the refractive index include, for example, silicon oxide, aluminum oxide, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide. The average primary particle size of the pigment may be 0.1 μm or less. By setting the average primary particle size of the pigment to 0.1 μm or less, it is possible to prevent diffused reflection of light passing through the refractive index adjusting layer and to prevent a decrease in transparency.

Examples of metals used for the refractive index adjusting layer include metals such as titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, and silicon nitride. Oxides or metal nitrides may be mentioned.

[Use]
The film of the present invention is useful, for example, as a front panel of an image display device, particularly a front panel (window film) of a flexible display. The film of the present invention can be arranged as a front plate on the viewing side surface of an image display device, particularly a flexible display. This front panel has a function of protecting the image display element in the flexible display.

Image display devices include televisions, smartphones, mobile phones, car navigation systems, tablet PCs, portable game machines, electronic paper, indicators, bulletin boards, watches, and wearable devices such as smart watches. Flexible displays include image display devices such as those described above that have flexible characteristics.

[Method for controlling morphology of polyamideimide resin]
A method for controlling the morphology of a polyamideimide resin composition of the present invention comprises a polyamideimide resin having at least a structural unit derived from an acid dianhydride, a structural unit derived from a carboxylic acid compound, and a structural unit derived from a diamine. A method for controlling the morphology of an imide resin composition, wherein 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride is added to the entire structural unit derived from the acid dianhydride. The ratio of structural units derived from a substance, the ratio of structural units derived from a carboxylic acid compound having an aromatic ring with respect to the entire structural units derived from the carboxylic acid compound, and the heat generation in DSC measurement of the polyamideimide resin composition The morphology of the polyamide-imide resin composition is controlled based on the peak area.

More specifically, the method for controlling the morphology of the polyamideimide resin composition of the present invention is 1,1′-bicyclohexane-3,3′,4 for the entire structural unit derived from the acid dianhydride. ,4'-Tetracarboxylic dianhydride-derived structural units account for more than 50 mol%, and structural units derived from a carboxylic acid compound having an aromatic ring are included in all structural units derived from the carboxylic acid compound. 50 mol% or more, and by adjusting the exothermic peak area of 0.1 mJ / mg or more and 21.0 mJ / mg or less when a sample obtained by forming a film of the polyamideimide resin composition is measured by DSC, the polyamideimide resin composition is The film is controlled so as to maintain the mechanical properties derived from the polyamide resin portion while ensuring proper compatibility that does not deteriorate the optical properties, thereby realizing a film that is colorless and transparent and has excellent mechanical properties.

EXAMPLES The present invention will be described more specifically with reference to examples below.

[Measurement evaluation method]
<Film thickness>
The thickness of the film was measured using a Mitutoyo micrometer.

<Appearance>
The film was visually observed to confirm whether it was transparent or whitened.

<Haze>
In accordance with JIS K 7136:2000, the film was cut into a size of 30 mm x 30 mm, and HAZE (%) was measured using a haze computer (manufactured by Suga Test Instruments Co., Ltd., "HGM-2DP").
HAZE is preferably 3% or less, more preferably 1% or less.

<Yellowness (YI value)>
The yellowness (Yellow Index: YI value) of the film was measured using an ultraviolet-visible-near-infrared spectrophotometer "V-670" manufactured by JASCO Corporation. After performing background measurement without a sample, set the film on the sample holder, measure the transmittance for light of 300 to 800 nm, obtain the tristimulus values (X, Y, Z), and use the following formula. Based on the YI value was calculated.
YI value = 100 x (1.2769X-1.0592Z)/Y
The YI value is preferably 5 or less, more preferably 2 or less.

<Total light transmittance (Tt)>
In accordance with JIS K 7361-1: 1997, the film was cut into a size of 30 mm × 30 mm, and the thickness of the optical film was measured using a haze computer (manufactured by Suga Test Instruments Co., Ltd., "HGM-2DP"). Total light transmittance (%) at 50 μm was measured.
The total light transmittance is preferably 85% or more, more preferably 88% or more.

<Exothermic peak area (DSC measurement)>
It was measured using a differential scanning calorimeter "DSC7200" manufactured by Hitachi High-Tech Science. A 10 mg piece of film was used as a sample, and the temperature range was 25 to 400° C. with a temperature increase rate of 10° C./min, a hold time of 30 minutes, a temperature decrease rate of 10° C./min, and two cycles. Regarding the exothermic peak confirmed at the first temperature rise, only the endothermic peak due to melting was observed at the second temperature rise after slow cooling, so it was confirmed to be derived from crystallization. Also, the area surrounded by the exothermic peak and the base line was defined as the exothermic peak area. Although the area of the exothermic peak of the DSC curve is generally calculated as a negative value, it is treated as an absolute value here.
A crystalline polymer is defined as having an exothermic peak area value of 0.1 mJ/mg or more as confirmed by the above DSC measurement.

<Glass transition temperature (Tg)>
In the DSC measurement, the peak top value of the endothermic peak observed at the first temperature rise was read and taken as the glass transition temperature (Tg).

<Young's modulus>
A film cut out with a width of 15 mm and a length of 170 mm was measured using a tabletop tester "STB-1225L" manufactured by A&D. A tensile test was performed under the conditions of a distance between chucks of 120 mm, a tensile speed of 10 mm/min, a temperature of 23° C. and a relative humidity of 50%. .
Young's modulus is preferably 3.5 GPa or more, more preferably 5.0 GPa or more. The upper limit of Young's modulus is about 10 GPa reported for polyamide resin.

<Elongation rate>
In the measurement of Young's modulus, the elongation at break with the largest value among N=3 was taken as the elongation.
The elongation rate is preferably 3% or more, more preferably 5% or more. Incidentally, the upper limit of the elongation rate is usually about 7%.

[Example 1]
4.80 g (0.0150 mol) of 2,2′-bistrifluoromethyl-4,4′-biphenyldiamine (TFDB) and 16.0 g (0.0150 mol) of N,N-dimethylacetamide (DMAc) were placed in a 300 mL reaction vessel replaced with a nitrogen gas atmosphere. 6 g was added and dissolved by stirring at room temperature. To this, 1.30 g (0.00420 mol) of 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride (H-BPDA) and 41.6 g of DMAc were added and Stirred for an hour.
Next, this solution was cooled in an ice bath, and 2.22 g (0.0109 mol) of 1,4-benzenedicarbonyl chloride (TPC) was divided into 5 portions so that the internal temperature was 5° C. or less. added over time. 25.0 g of DMAc was then added and the solution was heated to 70° C. and stirred for 1 hour.
After the solution was once cooled to room temperature, 3.74 g (0.0473 mol) of pyridine and 4.83 g (0.0473 mol) of acetic anhydride were added, heated to 70° C. and stirred for 1 hour.

After the resulting polyamideimide solution was cooled to room temperature, water was added to precipitate the resin, and the resin was collected by suction filtration and washed with water. The recovered resin was dried under reduced pressure until there was no change in weight to obtain a polyamideimide resin (H-BPDA/TPC/TFDB=28:72:100 mol ratio).
A DMAc solution of 16% by mass was prepared from the obtained polyamide-imide resin, applied onto a glass substrate with an applicator, heated from room temperature to 300°C at a constant rate over 60 minutes in an inert oven, and then heated to 300°C. After reaching and holding for 60 minutes, the heating was stopped and the temperature was cooled. The coating film thus obtained was peeled off from the glass substrate to obtain a polyamideimide resin film having a thickness shown in Table 1.
Table 1 shows the measurement results of the physical properties of the obtained polyamide-imide resin film.

[Example 2]
320 g (1.00 mol) of 2,2′-bistrifluoromethyl-4,4′-biphenyldiamine (TFDB) and 1110 g of N,N-dimethylacetamide (DMAc) were added to a 10 L reaction vessel replaced with a nitrogen gas atmosphere, Dissolved by stirring at room temperature. To this, 65.0 g (0.212 mol) of 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride (H-BPDA), 3,3',4,4' 20.8 g (0.0707 mol) of -biphenyltetracarboxylic dianhydride (BPDA) and 2770 g of DMAc were added and stirred at 70°C for 1 hour.
Next, this solution was cooled in an ice bath, and 148 g (0.727 mol) of 1,4-benzenedicarbonyl chloride (TPC) and 1,670 g of DMAc were each divided into 5 equal portions, and the internal temperature was maintained at 5°C or less. , TPC and DMAc were added alternately over 90 minutes. 600 g of DMAc was then added and the solution was heated to 70° C. and stirred for 2 hours.
Then, after cooling the solution once to room temperature, the solution was heated again to 50°C, then 250 g (3.15 mol) of pyridine and 322 g (3.15 mol) of acetic anhydride were added and further heated to 70°C. and stirred for 1 hour.

After cooling the solution to room temperature, the solution was diluted with DMAc and poured into a large amount of water, and the deposited precipitate was removed by suction filtration and washed with water. Then, the resulting precipitate was dried under reduced pressure at 120° C. until no weight change was observed, to obtain a polyamideimide resin (BPDA/H-BPDA/TPC/TFDB=7:21:72:100 mol ratio). .
The obtained polyamideimide resin was prepared with DMAc so as to form a uniform solution of 14% by mass, and film formation was carried out in the same manner as in Example 1 to obtain a polyamideimide resin film having a thickness shown in Table 1.
Table 1 shows the measurement results of the physical properties of the obtained polyamide-imide resin film.

[Comparative Example 1]
30.0 g (0.094 mol) of 2,2′-bistrifluoromethyl-4,4′-biphenyldiamine (TFDB) and 150 g of N,N-dimethylacetamide (DMAc) were placed in a 1 L reaction vessel replaced with a nitrogen gas atmosphere. was added and dissolved by stirring at room temperature. To this, 3.92 g (0.013 mol) of 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride (H-BPDA), 3,3',4,4' 3.765 g (0.013 mol) of -biphenyltetracarboxylic dianhydride (BPDA) and 150 g of DMAC were added and stirred at 70° C. for 1 hour.
Next, this solution was cooled in an ice bath, and 13.4 g (0.069 mol) of 1,4-benzenedicarbonyl chloride (TPC) was divided into 5 portions so that the internal temperature was 5° C. or less. added over time. 400 g of DMAc was then added and the solution was heated to 70° C. and stirred for 1 hour.

After the solution was once cooled to room temperature, 22.6 g (0.286 mol) of pyridine and 29.4 g (0.288 mol) of acetic anhydride were added, heated to 70° C. and stirred for 1 hour.
Then, reprecipitation purification and drying under reduced pressure were carried out in the same manner as in Example 1 to obtain a polyamideimide resin (BPDA/H-BPDA/TPC/TFDB=14:14:72:100 mol ratio).
The obtained polyamideimide resin was prepared with DMAc so as to form a uniform solution of 16% by mass, and film formation was carried out in the same manner as in Example 1 to obtain a polyamideimide resin film having a thickness shown in Table 1.
Table 1 shows the measurement results of the physical properties of the obtained polyamide-imide resin film.

From Table 1, the proportion of H-BPDA units is more than 50 mol%, and the proportion of structural units derived from a carboxylic acid compound having an aromatic ring with respect to the entire structural units derived from a carboxylic acid compound is 50 mol% or more polyamideimide resin. It can be seen that the film obtained from the polyamideimide resin composition containing is colorless and transparent and has excellent mechanical properties.

Claims (8)

A polyamideimide resin composition comprising a polyamideimide resin having at least a structural unit derived from an acid dianhydride, a structural unit derived from a carboxylic acid compound, and a structural unit derived from a diamine,
The proportion of structural units derived from 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride is more than 50 mol% with respect to the entire structural units derived from the acid dianhydride. and
A polyamide-imide resin composition, wherein the ratio of structural units derived from a carboxylic acid compound having an aromatic ring is 50 mol% or more with respect to the entire structural units derived from the carboxylic acid compound. 1,1′-bicyclohexane-3,3′,4,4′-tetracarboxylic acid relative to the total structural unit of the structural unit derived from the acid dianhydride and the structural unit derived from the carboxylic acid compound The polyamide-imide resin composition according to claim 1, containing 13 mol% or more and 30 mol% or less of structural units derived from a dianhydride. Polyamideimide resin composition according to claim 1 or 2 containing a structural unit derived from 3,3',4,4'-biphenyltetracarboxylic dianhydride as the structural unit derived from the acid dianhydride . 4. The polyamideimide resin composition according to any one of claims 1 to 3, wherein the structural unit derived from the carboxylic acid compound comprises a structural unit derived from 1,4-benzenedicarbonyl chloride. 5. The polyamide-imide resin composition according to any one of claims 1 to 4, which contains a structural unit derived from 2,2'-bistrifluoromethyl-4,4'-biphenyldiamine as the structural unit derived from diamine. A polyamideimide resin film obtained using the polyamideimide resin composition according to any one of claims 1 to 5. 7. The polyamide-imide resin film according to claim 6, which has an exothermic peak area of 0.1 mJ/mg or more and 21.0 mJ/mg or less when measured by DSC. A method for controlling the morphology of a polyamideimide resin composition having at least a structural unit derived from an acid dianhydride, a structural unit derived from a carboxylic acid compound, and a structural unit derived from a diamine,
The ratio of structural units derived from 1,1'-bicyclohexane-3,3',4,4'-tetracarboxylic dianhydride to the entire structural units derived from the acid dianhydride is 50 mol%. super and
50 mol% or more of structural units derived from a carboxylic acid compound having an aromatic ring relative to the entire structural units derived from the carboxylic acid compound;
A method for controlling the morphology of a polyamideimide resin composition, comprising controlling an exothermic peak area of 0.1 mJ/mg or more and 21.0 mJ/mg or less when a sample obtained by forming a film of the polyamideimide resin composition is measured by DSC.