KR102077639B1 - Optical film - Google Patents

Abstract

Provided is an optical film capable of achieving low yellowness (YI value) and high elastic modulus.
Including a polyamide-imide-based resin, when the film cross section is measured by the time-of-flight secondary ion mass spectrometry, the intensity ratio (A / B) of methoxy ionic strength (A) and silicon ionic strength (B) is 0.02 or more. , Optical film.

Description

Optical film {OPTICAL FILM}

This invention relates to the optical film used as a front plate etc. of an image display apparatus, its manufacturing method, and the flexible image display apparatus provided with the said optical film.

Image display apparatuses, such as a liquid crystal display device and an organic electroluminescence display, are widely utilized for various uses, such as a mobile telephone and a smart watch. Although glass has been used as the front plate of such an image display device, since glass is very rigid and brittle, it is difficult to use it as a front plate material, such as a flexible display, for example. As one of the materials replacing the glass, there is a polyimide resin, and an optical film using such a resin is studied (for example, Patent Document 1).

International Publication No. 2017/119450

The optical film used for the front plate of such an image display apparatus requires a high elastic modulus in addition to the outstanding optical characteristics, such as low yellowness (YI value). However, according to the examination by the present inventors, it turned out that the optical film containing a polyimide resin may not be compatible with low yellowness (YI value) and high elastic modulus.

Therefore, the objective of this invention is providing the optical film which can make low yellowness (YI value) and high elastic modulus compatible, its manufacturing method, and the flexible image display apparatus provided with the said optical film.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, when an optical film contains a polyamide-imide-type resin and measured the said film cross section by time-of-flight type | mold secondary ion mass spectrometry, a methoxy ion intensity (A When the ratio (A / B) of the (I) and the silicon ionic strength (B) is 0.02 or more, it was found that the above object is achieved and the present invention has been completed. That is, the following aspects are included in the present invention.

[1] An optical film containing a polyamideimide-based resin, wherein when the film cross section is measured by a time-of-flight secondary ion mass spectrometry, an intensity ratio between methoxy ionic strength (A) and silicon ionic strength (B) ( A / B) is 0.02 or more, an optical film.

[2] The optical film according to [1], wherein the silica particles are contained and the content of the silica particles is 45% by mass or less with respect to the mass of the optical film.

[3] The optical film according to [1] or [2], wherein the film thickness is 20 µm or more.

[4] The optical film according to any one of [1] to [3], wherein the weight average molecular weight of the polyamide-imide resin is 100,000 to 500,000.

[5] The method for producing the optical film according to any one of [1] to [4], including a step of solvent-substituting a methanol-dispersed silica sol.

[6] The method according to [5], further comprising a step of preparing a varnish by mixing a solvent-substituted silica sol with a polyamideimide-based resin.

[7] The method of [6], further comprising the step of applying the varnish to the substrate to form a coating film.

[8] The method of [7], further comprising a step of drying the coating film to form an optical film.

[9] A flexible image display device comprising the optical film according to any one of [1] to [4].

[10] The flexible image display device according to [9], further comprising a polarizing plate.

[11] The flexible image display device according to [9] or [10], further comprising a touch sensor.

Since the low yellowness (YI value) and a high elastic modulus are compatible, the optical film of this invention can be used as a front plate material of an image display apparatus.

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 embodiment described here, A various change is possible in the range which does not deviate from the meaning of this invention.

[Optical film]

The optical film of this invention contains a polyamide-imide-type resin, and when the said film cross section is measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS) method, The intensity ratio (A / B) of oxy (MeOH) ionic strength (A) and silicon (Si) ionic strength (B) is 0.02 or more.

In order to calculate the said intensity ratio A / B, the cross section of an optical film is measured using TOF-SIMS. It does not specifically limit as a method of manufacturing the cross section of an optical film, For example, even if it uses the ion milling method which irradiates an ion beam to an optical film and produces a smooth cross section along the edge part of the shielding plate provided directly on the optical film. Alternatively, processing by precision mechanical polishing or cutting by microtome may be used. From the viewpoint of low damage to the resin film, cross-sectional production using cutting with a microtome is preferable.

The TOF-SIMS method is a kind of mass spectrometry. According to TOF-SIMS, an element or molecule which exists on the outermost surface of a sample can be obtained with a very high detection sensitivity, and an element or molecule that exists on the outermost surface of the sample. The distribution of species can also be investigated.

TOF-SIMS method is a method of irradiating an ion beam (primary ion) to a sample in high vacuum, and mass-separating the ion emitted from the surface using the time-of-flight difference. When irradiated with primary ions, positive or negatively charged ions (secondary ions) are released from the surface of the sample, but lighter ones are faster and heavier ones fly later, until secondary ions are detected. By measuring the time (flight time), the mass of the generated secondary ion can be calculated.

In the measurement in the TOF-SIMS method, methoxy (CH ₃ O) ions are detected near 31.02 u in mass and silicon (Si) ions near 27.98 u in mass. The intensity ratio (A / B) can be calculated by setting the integral value of the peak of the methoxy ion as the (detection) intensity A of the CH ₃ O ion and the integral value of the peak of the silicon ion as the (detection) intensity B of the Si ion. Can be. Moreover, these ions are ions detected in either positive (positive) analysis or negative (negative) analysis. The intensity ratio (A / B) in the present invention may be an intensity ratio (A / B) detected by positive ion analysis, or an intensity ratio (A / B) detected by negative ion analysis, or at least one of If the intensity ratio (A / B) is 0.02 or more, the requirement that the intensity ratio (A / B) of methoxy ionic strength (A) and silicon ionic strength (B) in the present invention is 0.02 or more is satisfied.

The measurement according to the TOF-SIMS method was carried out using a TOF-SIMS apparatus under the conditions that the primary ions were Bi ³⁺ , the acceleration voltage of the primary ions was 25 kV, the irradiation ion current was 0.23 pA, and the measurement range was 200 μm × 200 μm. And positive ion analysis or negative ion analysis. The measurement by TOF-SIMS method can be performed by the method as described in an Example, for example.

In the optical film containing polyamide-imide-based resin, an optical film is surprisingly provided that the intensity ratio (A / B) of MeOH ion intensity (A) and Si ion intensity (B) measured by TOF-SIMS method is 0.02 or more. The yellowness (YI value) of is effectively reduced. For this reason, the optical film of the present invention may have a low yellowness (YI value). On the other hand, when the intensity ratio A / B is less than 0.02, yellowness (YI value) tends to be not effectively reduced, and low yellowness (YI value) and high modulus of elasticity tend not to be compatible. .

In the optical film of the present invention, the intensity ratio (A / B) is preferably 0.03 or more, more preferably 0.04 or more, and still more preferably 0.05 or more. When the said intensity ratio (A / B) is more than the said minimum, the yellowness (YI value) of an optical film can be reduced more effectively, and the optical film which has a lower yellowness (YI value) can be obtained. The upper limit of the said strength ratio A / B is 1.

Yellowness (YI value) of the optical film of this invention becomes like this. Preferably it is 3.0 or less, More preferably, it is 2.5 or less, More preferably, it is 2.2 or less. If yellowness of an optical film is below the said upper limit, transparency will become favorable, and when used for the front plate of an image display apparatus, it can contribute to high visibility. Moreover, yellowness is -5 or more normally, Preferably it is -2 or more. In addition, the yellowness (YI value) is measured using a UV-visible near-infrared spectrophotometer to measure the transmittance for light of 300 to 800 nm, to obtain tristimulus values (X, Y, Z), and YI = 100 × (1.2769X). Can be calculated based on the formula -1.0592Z) / Y. Yellowness can be measured by the method as described in an Example, for example.

Since the optical film of this invention contains predetermined polyamide-imide-type resin, it can have high elasticity modulus. The tensile modulus of the optical film of the present invention is preferably 5.5 GPa or more, more preferably 6.0 GPa or more, still more preferably 6.3 GPa or more. Tensile modulus is usually 100 GPa or less. In addition, an elasticity modulus can be measured using a tensile tester (500 mm between spine distance, 20 mm / min of tensile velocity), and can be measured by the method as described in an Example, for example.

The optical film of this invention is also excellent in optical characteristics other than low yellowness (YI value). In this specification, an optical characteristic shows the optically evaluable characteristics, such as yellowness (YI value), all-light transmittance, and haze, for example, Haze (Haze) The yellowness (YI value) is low, the total light transmittance is high, etc. are shown.

In the optical film of the present invention, the total light transmittance at a thickness of 50 μm is preferably 80% or more, more preferably 85% or more, still more preferably 88% or more, even more preferably 89% or more, particularly Preferably it is 90% or more. If total light transmittance is more than the said minimum, transparency will become favorable, and when used for the front plate of an image display apparatus, it can contribute to high visibility. In addition, the upper limit of total light transmittance is 100% or less normally. In addition, total light transmittance can be measured using a haze computer based on JISK7361-1: 1997, For example, it can measure by the method as described in an Example. In addition, since the optical film of the present invention exhibits high total light transmittance, for example, in the flexible device, when the same brightness is obtained, the light emission intensity such as a backlight can be lowered, it can contribute to energy saving. .

Haze of the optical film of this invention becomes like this. Preferably it is 1% or less, More preferably, it is 0.5% or less, More preferably, it is 0.2% or less. If the haze of an optical film is below the said upper limit, transparency will become favorable, and when used for the front plate of an image display apparatus, it can contribute to high visibility. Moreover, the lower limit of haze is 0.01% or more normally. In addition, a haze can be measured using a haze computer based on JISK7136: 2000, For example, it can measure by the method as described in an Example.

The film thickness of the optical film of the present invention is preferably 20 μm or more, more preferably 25 μm or more, even more preferably 30 μm or more, preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less. May be a combination of these upper and lower limits. It is easy to improve the elasticity modulus of an optical film as the thickness of an optical film is the said range. In addition, the film thickness of an optical film can be measured using a micrometer, for example, can be measured by the method as described in an Example.

The optical film of this invention has the outstanding bending resistance. In the optical film of the present invention, the number of times of bending (bending radius R = 1mm) in the bending resistance test is preferably 150,000 times or more, more preferably 180,000 times or more, further preferably 200,000 times or more. If the number of times of bending is more than the above lower limit, it has sufficient bending resistance as a front plate material such as a flexible display. In addition, the frequency | count of bending in a bending resistance test is repeated using the bending test machine on condition that bending radius (curvature radius) R is 1 mm, and repeating bending of an optical film, and the reciprocation to the time point which a crack generate | occur | produces in the said film The number of bendings (one reciprocation is performed once) can be measured and measured by, for example, the method described in Examples.

<Resin>

The optical film of this invention contains polyamide-imide-type resin. When polyamide-imide resin is included, elastic modulus and flex resistance can be improved.

The polyamide-imide resin refers to a polymer containing a repeating structural unit containing an imide group and a repeating structural unit containing an amide group. In addition, in this specification, a repeating structural unit may be called a structural unit.

It is preferable that polyamide-imide-type resin contains the repeating structural unit represented by Formula (10) and the repeating structural unit represented by Formula (13). Herein, G is a tetravalent organic group, G ³ is a divalent organic group, and A and A ³ are each a divalent organic group. The polyamideimide-based resin is a repeating structural unit represented by two or more kinds of formulas (10) in which G and / or A is different, or a repeating structure represented by two or more kinds of formulas (13) in which G ³ and / or A ³ are different. It may contain a unit. Polyamide-imide-based resin may contain one or more selected from the group consisting of a repeating structural unit represented by formula (11) and a repeating structural unit represented by formula (12) within a range that does not impair various physical properties of the optical film. do.

In Formulas (10) and (11), G and G ¹ are each independently a tetravalent organic group, and preferably an organic group which may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon group. Examples G and G ^1, formula 20, formula 21, formula 22, formula 23, formula 24, formula 25, formula 26, formula 27, formula 28 Or the group represented by Formula (29) and a tetravalent hydrocarbon group of 6 or less carbon atoms are illustrated. From the viewpoint of easy to reduce the yellowness (YI value) of the optical film, among them, formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), formula Group represented by (26) or Formula (27) is preferable, and group represented by Formula (26) is preferable in order to obtain the optical film which has especially the outstanding elasticity modulus.

In formulas (20) to (29),

* Represents a bonding hand,

Z 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- is represented. Ar represents the C6-C20 arylene group which may be substituted by the fluorine atom, and a phenylene group is mentioned as a specific example.

Equation (12), G ² is a trivalent organic group, preferably an organic group which may be substituted with a hydrocarbon group or a fluorine-substituted hydrocarbon groups (fluorinated substituent). Examples of G ^2, formula 20, formula 21, formula 22, formula 23, formula 24, formula 25, formula 26, formula 27, formula 28 or formula The group by which any one of the bonds of group represented by (29) was substituted by the hydrogen atom, and the trivalent C6 or less chain hydrocarbon group are illustrated.

Expression (13) in, G ³ is a divalent organic group, preferably an organic group which may be substituted with a hydrocarbon group or a fluorinated substituent. Examples of G ^3, formula 20, formula 21, formula 22, formula 23, formula 24, formula 25, formula 26, formula 27, formula 28 or formula Among the bonds of the group represented by (29), groups in which two non-adjacent groups are substituted with hydrogen atoms and a chain hydrocarbon group having 6 or less carbon atoms are exemplified.

In Formulas (10) to (13), A, A ¹ , A ² and A ³ each independently represent a divalent organic group, and preferably an organic group which may be substituted with a hydrocarbon group or a fluorine-containing substituent. As the A, A ^1, A ² and A ^3, formula 30, formula 31, formula 32, formula 33, formula 34, formula 35, formula 36, formula (37 ) Or a group represented by formula (38); Groups in which they are substituted with a methyl group, a fluoro group, a chloro group or a trifluoromethyl group; And a C6 or less chain hydrocarbon group is illustrated.

In formula (30)-formula (38),

* Represents a bonding hand,

Z ¹ , Z ² and Z ³ are each independently a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) ₂ -,- C (CF ₃ ) _2- , -SO ₂ -or -CO-.

One example is that Z ¹ and Z ³ are -O-, and Z ² is -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) ₂ -or -SO _2- . The bonding position for each ring of Z ¹ and Z ² and the bonding position for each ring of Z ² and Z ³ are each preferably a meta position or a para position, more preferably a para position for each ring.

In one embodiment of the present invention, the polyamide-imide-based resin may include plural kinds of G ³ , and plural kinds of G ³ may be the same as or different from each other. In particular, from the viewpoint of improving the surface hardness and the flex resistance and decreasing the yellowness of the resulting optical film, at least a part of G ³ is represented by the formula (3):

Equation (3) of, R ¹ ~ R ⁸ each independently represent an aryl group of a hydrogen atom, a C 1 -C 6 alkyl group or a C 6 to 12, R ¹ ~ hydrogen atoms contained in R ⁸ is a halogen, each independently May be substituted by an atom,

B is a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) _2- , -C (CF ₃ ) ₂ -,- SO _2- , -S-, -CO- or -N (R ⁹ )-, R ⁹ represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a hydrogen atom or a halogen atom,

n is an integer of 0 to 4,

* Represents a bonding hand]

It is preferable that it is a structural unit represented by.

In formula (3), B is independently a single bond, -O-, -CH _2- , -CH ₂ -CH _2- , -CH (CH ₃ )-, -C (CH ₃ ) ₂ -,- C (CF ₃ ) _2- , -SO _2- , -S-, -CO- or -NR ^9- , and from the viewpoint of improving the bending resistance of the optical film, preferably -O- or -S-. More preferably, -O- is represented. R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and 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. Examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and 2-methyl-butyl group , 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl group and the like. Moreover, as a C6-C12 aryl group, a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group etc. are mentioned, for example. From the viewpoint of surface hardness and flexibility of the optical film, R ¹ to R ⁸ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. More preferably represents a hydrogen atom. Here, the hydrogen atoms contained in R ¹ to R ⁸ may be each independently substituted with a halogen atom.

R <^9> represents the C1-C12 hydrocarbon group which may be substituted by the hydrogen atom and the halogen atom. R <^9> represents the C1-C12 monovalent hydrocarbon group which may be substituted by the hydrogen atom and the halogen atom. Examples of the monovalent hydrocarbon group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and 2- Methyl-butyl group, 3-methylbutyl group, 2-ethyl-propyl group, n-hexyl group, n-heptyl group, n-octyl group, tert-octyl group, n-nonyl group, n-decyl group, etc. are mentioned. These may be substituted by the halogen atom. As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned.

In Formula (3), n is an integer of the range of 0-4, and if n is in this range, optical characteristics, such as the bending resistance, elastic modulus, and low yellowness of an optical film, are favorable. In formula (3), n is preferably an integer in the range of 0 to 3, more preferably an integer in the range of 0 to 2, still more preferably 0 or 1, and n is within this range. The optical properties such as bending resistance, elastic modulus and low yellowness of the optical film are good, and the availability of the raw material is relatively good. Moreover, G <^3> may include the 1 type (s) or 2 or more types of structural units represented by Formula (3), and especially n from a viewpoint of the improvement of the elasticity modulus and bending resistance of an optical film, and reduction of a yellowness (YI value), Two or more types of structural units from which the value of is different may be included, Preferably two types of structural units from which the value of n differs may be included. In that case, it is preferable that n contains both the structural units of 0 and 1 from a viewpoint that an optical film is easy to express high elastic modulus, bending resistance, and low yellowness (YI value).

In a preferred embodiment of the present invention, formula (3) is a structural unit or formula (3 ') wherein n = 0 and R ¹ to R ⁸ are hydrogen atoms:

It is a structural unit shown by these, These can also be used together. In this case, an optical film can exhibit high surface hardness, can have high bending resistance, and can make yellowness low.

In preferable embodiment of this invention, about the sum total of the structural unit represented by Formula (10) of polyamide-imide-type resin, and the structural unit represented by Formula (13), it is Formula (3) when n is 0-4. The structural unit to be represented is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, particularly preferably 50 mol% or more, most preferably 60 mol% or more, Preferably it is 90 mol% or less, More preferably, it is 85 mol% or less, More preferably, it is 80 mol% or less. About the sum total of the structural unit represented by Formula (10) in a polyamide-imide-type resin, and the structural unit represented by Formula (13), if n is 0-4, the structural unit represented by Formula (3) is more than the said minimum. The optical film can express high surface hardness and can be excellent in flex resistance and elastic modulus. About the sum total of the structural unit represented by Formula (10) in a polyamide-imide-type resin, and the structural unit represented by Formula (13), if the structural unit represented by Formula (3) when n is 0-4 is less than the said upper limit By suppressing the thickening by the hydrogen bond between the amide bonds derived from Formula (3), the viscosity of the resin varnish can be suppressed and the processing of an optical film can be made easy.

In a preferred embodiment of the present invention, n in formula (3) is represented by 1 to 4 with respect to the sum of the structural units represented by formula (10) of the polyamide-imide-based resin and the structural units represented by formula (13). The unit is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 7 mol% or more, particularly preferably 9 mol% or more, preferably 90 mol% or less, and more preferably Is 70 mol% or less, more preferably 50 mol% or less, particularly preferably 30 mol% or less. About the sum total of the structural unit represented by Formula (10) in a polyamide-imide-type resin, and the structural unit represented by Formula (13), if the structural unit represented by n of Formula (3) to 1-4 is more than the said minimum, it is optical. While a film can express high surface hardness, bending resistance improves more. About the sum total of the structural unit represented by Formula (10) in polyamide-imide-type resin, and the structural unit represented by Formula (13), if the structural unit represented by n of Formula (3) to 1-4 is below the said upper limit, a formula (3) By suppressing the thickening due to hydrogen bonding between the amide bonds derived, the viscosity of the resin varnish can be suppressed and the processing of the optical film can be facilitated. The content of the structural unit represented by the formula (3) is, for example, can be measured by using a ¹ H-NMR, or may be calculated from the raw material doipbi.

In a preferred embodiment of the present invention, G ³ of the polyamideimide-based resin, preferably 5 mol% or more, more preferably 8 mol% or more, still more preferably 10 mol% or more, particularly preferably 12 mol% or more is represented by Formula (3) when n is 1-4. When the lower limit or more of G <^3> of polyamide-imide-type resin is represented by Formula (3) when n is 1-4, an optical film may express high surface hardness and may have high bending resistance. Further, G ^{3 in} the polyamideimide-based resin is preferably 90 mol% or less, more preferably 70 mol% or less, still more preferably 50 mol% or less, particularly preferably 30 mol% or less. It is preferable to represent by Formula (3) in the case of 1-4. By a polyamide-imide-based resin of the upper limit or less of G ^3, n If the formula (3) in the case where the 1 to 4, inhibiting the viscosity by hydrogen bonding between the amide bond of the formula (3) derived from the resin varnish A viscosity can be suppressed and the process of an optical film can be made easy.

In a preferred embodiment of the present invention, G ^{3 in} the polyamideimide-based resin, preferably 30 mol% or more, more preferably 50 mol% or more, particularly preferably 70 mol% or more, n is 0 It is represented by Formula (3) when it is -4. When more than the said lower limit of G <^3> of polyamide-imide-type resin is represented by Formula (3) when n is 0-4, an optical film may express high surface hardness and may have high bending resistance. Moreover, it is preferable that 100 mol% or less of G <^3> in polyamide-imide-type resin is preferably represented by Formula (3) when n is 0-4. Poly by which the upper limit value or less of a G ^{3-imide-based} resin, n appears in equation (3) when the 0 to 4, and suppress the viscosity by hydrogen bonding between the amide bond of the formula (3) derived from a resin varnish The viscosity of can be suppressed and the processing of an optical film can be made easy. In addition, the polyamide-imide-based content of the constituent unit represented by of the formula (3) resin is, for example, can be measured by using a ¹ H-NMR, or may be calculated from the raw material doipbi.

In a preferred embodiment of the present invention, at least a part of the plurality of A and A ^{3 in} the formulas (10) and (13) is represented by the formula (4):

[In formula (4), R <^10> -R <^17> respectively independently represents a hydrogen atom, a C1-C6 alkyl group, or a C6-C12 aryl group, and the hydrogen atom contained in R <^10> -R <^17> is each independently halogen May be substituted by an atom, and * represents a bond.]

It is a structural unit represented by. If at least some of A and A <^3> in Formula (10) and (13) is group represented by Formula (4), an optical film can express high surface hardness, and can have high transparency.

In formula (4), R <^10> , R <^11> , R <^12> , R <^13> , R <^14> , R <^15> , R <^16> and R <^17> are respectively independently a hydrogen atom, a C1-C6 alkyl group, or a C6-C12 aryl Group. As a C1-C6 alkyl group or a C6-C12 aryl group, what was illustrated as a C1-C6 alkyl group or C6-C12 aryl group in Formula (3) is mentioned. R ¹⁰ to R ¹⁷ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, which are contained in R ¹⁰ to R ¹⁷ herein. Each hydrogen atom to be independently may be substituted with a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, for example. R ¹⁰ to R ¹⁷ are each independently from the viewpoint of surface hardness, transparency and bend resistance of the optical film, more preferably a hydrogen atom, a methyl group, a fluoro group, a chloro group or a trifluoromethyl group, and particularly preferably R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , and R ¹⁶ are hydrogen atoms, R ¹¹ and R ¹⁷ are hydrogen atoms, methyl groups, fluoro groups, chloro groups or trifluoromethyl groups, in particular R ¹¹ and R It is preferable that ¹⁷ is a methyl group or a trifluoromethyl group.

In a preferred embodiment of the present invention, the structural unit represented by formula (4) is represented by formula (4 '):

In other words, at least a part of a plurality of A and A ³ is a structural unit represented by Formula (4 '). In this case, while the optical film expresses high transparency, the solubility to the solvent of the said polyamide-imide-type resin can be improved by the frame | skeleton containing a fluorine element, the viscosity of resin varnish can be suppressed low, and the optical Processing of the film can be facilitated.

In a preferred embodiment of the present invention, A and A ^{3 in} the polyamideimide system, preferably 30 mol% or more, more preferably 50 mol% or more, still more preferably 70 mol% or more are represented by the formula (4 ), In particular formula (4 '). When A and A <^{3> in} the said range in the said polyamide-imide-type resin are represented by Formula (4), especially Formula (4 '), an optical film expresses high transparency and is made to the skeleton containing a fluorine element. As a result, the solubility of the polyamideimide resin in the solvent can be improved, the viscosity of the resin varnish can be suppressed low, and the processing of the optical film can be facilitated. Preferably, the polyamide-imide resin of not more than 100 mol% of A ³ and A is represented by formula (4), particularly formula (4 '). The polyamide-imide-based resin in the A and A ³ can be either formula (4), in particular (4 '). Of the constituent unit represented by the formula and A 4 of the A ³ of the polyamide-imide-based resin it is, for example, can be measured by using a ¹ H-NMR, or may be calculated from the raw material doipbi.

In a preferred embodiment of the present invention, at least a portion of the plurality of G in Formula (10) is represented by Formula (5):

[In formula (5), R <^18> -R <^25> respectively independently represents a hydrogen atom, a C1-C6 alkyl group, or a C6-C12 aryl group, and the hydrogen atom contained in R <^18> -R <^25> is each independently halogen May be substituted by an atom, and * represents a bond.]

It is a structural unit represented by. If at least one part of the some G in Formula (10) is group represented by Formula (5), an optical film will express high transparency, and will improve the solubility to the solvent of polyamide-imide-type resin, A viscosity can be suppressed low and the process of an optical film can be made easy.

In Formula (5), R <^18> , R <^19> , R <^20> , R <^21> , R <^22> , R <^23> , R <^24> and R <^25> are respectively independently a hydrogen atom, a C1-C6 alkyl group, or a C6-C12 aryl Group. As a C1-C6 alkyl group or a C6-C12 aryl group, what was illustrated as a C1-C6 alkyl group or C6-C12 aryl group in Formula (3) is mentioned. R ¹⁸ to R ²⁵ each independently preferably represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, which are contained in R ¹⁸ to R ²⁵ herein. Each hydrogen atom to be independently may be substituted with a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. R ¹⁸ to R ²⁵ each independently represent a hydrogen atom, a methyl group, a fluoro group, a chloro group, or a trifluoromethyl group from the viewpoint of improving the surface hardness, the flex resistance, and the transparency of the optical film, more independently. More preferably R ¹⁸ , R ¹⁹ , R ²⁰ , R ²³ , R ²⁴ , and R ²⁵ are hydrogen atoms, R ²¹ and R ²² are hydrogen atoms, methyl groups, fluoro groups, chloro groups or trifluoromethyl groups, It is particularly preferable that R ²¹ and R ²² be a methyl group or a trifluoromethyl group.

In preferable embodiment of this invention, the structural unit represented by Formula (5) is Formula (5 '):

In other words, at least a part of the plurality of G's is a structural unit represented by Formula (5 '). In this case, the optical film may have high transparency.

In a preferred embodiment of the present invention, G in the polyamideimide-based resin, preferably 50 mol% or more, more preferably 60 mol% or more, still more preferably 70 mol% or more is represented by the formula (5), In particular, it is represented by Formula (5 '). When G in the said range in the said polyamide-imide-type resin is represented by Formula (5), especially Formula (5 '), an optical film may have high transparency, and the said poly film is further made by the frame | skeleton containing a fluorine element. The solubility of the amidimide-based resin in the solvent can be improved, the viscosity of the resin varnish can be suppressed low, and the production of the optical film is easy. Moreover, Preferably, 100 mol% or less of G in the said polyamide-imide-type resin is represented by Formula (5), especially Formula (5 '). Formula (5), especially (5 ') may be sufficient as G in the said polyamide-imide-type resin. The polyamide-imide-based content of the constituent unit represented by the formula (5) the G of the resin is, for example, can be measured by using a ¹ H-NMR, or may be calculated from the raw material doipbi.

In one embodiment of the present invention, the polyamide-imide resin is a diamine, a tetracarboxylic acid compound (tetracarboxylic acid compound flexible body such as an acid chloride compound, tetracarboxylic dianhydride) and Dicarboxylic acid compounds (dicarboxylic acid compound flexible bodies such as acid chloride compounds) and, if necessary, tricarboxylic acid compounds (tricarboxylic acid compound flexible bodies such as acid chloride compounds and tricarboxylic anhydrides); It is a condensation type polymer obtained by making it react (polycondensation). The repeating structural unit represented by Formula (10) or Formula (11) is usually derived from a diamine and a tetracarboxylic acid compound. The repeating structural unit represented by Formula (12) is usually derived from a diamine and a tricarboxylic acid compound. The repeating structural unit represented by Formula (13) is usually derived from a diamine and a dicarboxylic acid compound.

As a tetracarboxylic-acid compound, Aromatic tetracarboxylic-acid compounds, such as aromatic tetracarboxylic dianhydride; And aliphatic tetracarboxylic acid compounds such as aliphatic tetracarboxylic dianhydrides. A tetracarboxylic-acid compound may be used independently and may use 2 or more types together. In addition to the dianhydride, the tetracarboxylic-acid compound may be a tetracarboxylic-acid compound flexible body, such as an acid chloride compound.

As a specific example of aromatic tetracarboxylic dianhydride, 4,4'- oxydiphthalic dianhydride, 3,3 ', 4,4'- benzophenone tetracarboxylic dianhydride, 2,2', 3,3'- Benzophenonetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (may be referred to as BPDA), 2,2', 3,3'-biphenyltetra Carboxylic dianhydride, 3,3 ', 4,4'-diphenylsulfontetracarboxylic 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 ( 6FDA), 1,2-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,2-bis (3,4-di Carboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, bis (3,4-dicarboxyphenyl) methane di Water, bis (2,3-dicarboxyphenyl) methane dianhydride and 4,4 '-(p-phenylenedioxy) diphthalic dianhydride and 4,4'-(m-phenylenedioxy) diphthalic dianhydride ( 6FDA). These can be used individually or in combination of 2 or more types.

As aliphatic tetracarboxylic dianhydride, a cyclic or acyclic aliphatic tetracarboxylic dianhydride is mentioned. A cyclic aliphatic tetracarboxylic dianhydride is tetracarboxylic dianhydride which has alicyclic hydrocarbon structure, As a specific example, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 1,2, Cycloalkanetetracarboxylic dianhydride, such as 3, 4- cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, bicyclo [2.2.2] oct-7 -En-2,3,5,6-tetracarboxylic dianhydride, dicyclohexyl 3,3'-4,4'- tetracarboxylic dianhydride, and these positional isomers are mentioned. 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, 1,2,3,4-pentanetetracarboxylic dianhydride, and the like. Silver can be used individually or in combination of 2 or more types. Moreover, you may use combining a cyclic aliphatic tetracarboxylic dianhydride and an acyclic aliphatic tetracarboxylic dianhydride.

Among the tetracarboxylic dianhydrides, 1,2,4,5-cyclohexanetetracarboxylic dianhydride and bicyclo [2.2.2] oct-7- from the viewpoint of reducing yellowness and increasing transparency. Preference is given to en-2,3,5,6-tetracarboxylic dianhydride and 4,4 '-(hexafluoroisopropylidene) diphthalic dianhydride, and mixtures thereof. Moreover, you may use the aqueous addition product of the anhydride of the said tetracarboxylic-acid compound as tetracarboxylic acid.

As a tricarboxylic acid compound, aromatic tricarboxylic acid, aliphatic tricarboxylic acid, those flexible acid chloride compounds, an acid anhydride, etc. are mentioned, You may use 2 or more types together. Specific examples include anhydrides of 1,2,4-benzenetricarboxylic acid; 2,3,6-naphthalenetricarboxylic acid-2,3- anhydride; And phthalic anhydride and benzoic acid include a single bond, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ -or a phenylene group.

As a dicarboxylic acid compound, aromatic dicarboxylic acid, aliphatic dicarboxylic acid, those flexible acid chloride compounds, an acid anhydride, etc. are mentioned, You may use together 2 or more types. Specific examples thereof include terephthalic acid dichloride; Isophthalic acid dichloride; Naphthalenedicarboxylic acid chloride; 4,4'-biphenyldicarboxylic acid chloride; 3,3'-biphenyldicarboxylic acid chloride; 4,4'-oxybis (benzoylchloride) (OBBC); Dicarboxylic acid compounds of a chain hydrocarbon having 8 or less carbon atoms and two benzoic acids are a single bond, -CH _2- , -C (CH ₃ ) _2- , -C (CF ₃ ) _2- , -SO ₂ -or phenyl The compound connected with the rene group is mentioned. Among these dicarboxylic acid compounds, terephthaloyl chloride and 4,4'-oxybis (benzoyl chloride) are more preferable. These dicarboxylic acids can be used individually or in combination of 2 or more types.

As a diamine, an aliphatic diamine, aromatic diamine, or a mixture thereof is mentioned, for example. In addition, in this embodiment, "aromatic diamine" represents the diamine which the amino group couple | bonded with the aromatic ring directly, and may contain the aliphatic group or other substituent in a part of the structure. The aromatic ring may be monocyclic or condensed, and examples thereof include, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, and the like. Among these, it is preferable that an aromatic ring is a benzene ring. Moreover, "aliphatic diamine" shows the diamine which the amino group couple | bonded with the aliphatic group directly, and may contain the aromatic ring and other substituent in a part of the 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 4,4 '. Cyclic aliphatic diamines, such as diamino dicyclohexyl methane, etc. are mentioned. These can be used individually or in combination of 2 or more types.

As aromatic diamine, p-phenylenediamine, m-phenylenediamine, 2, 4-toluenediamine, m- xylylenediamine, p- xylylenediamine, 1, 5- diamino naphthalene, 2, 6, for example Aromatic diamines having one aromatic ring such as -diaminonaphthalene; 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylether, 3,4'-diaminodiphenylether, 3,3'-dia Minodiphenylether, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 1,4-bis (4-aminophenoxy) Benzene, 1,3-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 (tri Fluoromethyl) benzidine (2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (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-3-chlorophenyl) fluorene, 9, Two or more aromatic rings, such as 9-bis (4-amino-3-fluorophenyl) fluorene There may be mentioned aromatic diamine. These can be used individually or in combination of 2 or more types. Moreover, aliphatic diamine and aromatic diamine can also be combined.

It is preferable to use 1 or more types chosen from the group which consists of aromatic diamine which has a biphenyl structure from a viewpoint of reducing yellowness and improving transparency among the said diamine. Consisting of 2,2'-dimethylbenzidine, 2,2'-bis (trifluoromethyl) benzidine, 4,4'-bis (4-aminophenoxy) biphenyl and 4,4'-diaminodiphenylether It is more preferable to use at least 1 type selected from the group, and even more preferably to use 2,2'-bis (trifluoromethyl) benzidine.

The polyamideimide-based resin is a diamine, a tetracarboxylic acid compound, a dicarboxylic acid compound, and if necessary, each raw material such as a tricarboxylic acid compound by a conventional method, for example, a method such as stirring After mixing, the obtained intermediate can be obtained by imidization in the presence of an imidization catalyst and, if necessary, a dehydrating agent.

Although it does not specifically limit as an imidation catalyst used at an imidation process, For example, Aliphatic amines, such as tripropylamine, dibutylpropylamine, 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 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 3-ethylpyridine, 4-ethylpyridine, 2,4-dimethylpyridine, 2,4,6-trimethylpyridine, 3,4 Aromatic amines such as cyclopentenopyridine, 5,6,7,8-tetrahydroisoquinoline, and isoquinoline.

Examples of the dehydrating agent used in the imidation step include, but are not particularly limited to, acetic anhydride, propionic anhydride, isobutyric anhydride, pivalic anhydride, butyric anhydride, isovaleric anhydride, and the like.

Although the reaction temperature is not specifically limited in the mixing and imidation process of each raw material, For example, it is 15-350 degreeC, Preferably it is 20-100 degreeC. Although reaction time is not specifically limited, for example, It is about 10 minutes-about 10 hours. If necessary, the reaction may be performed under inert atmosphere or reduced pressure conditions. Moreover, you may perform reaction in a solvent, As a solvent, what was illustrated as a solvent used for preparation of a varnish, for example is mentioned. After the reaction, the polyamideimide resin is purified. As the purification method, for example, a poor solvent is added to the reaction solution to precipitate the resin by reprecipitation, and dried to take out the precipitate, and if necessary, the precipitate is washed with a solvent such as methanol and dried. have.

The weight average molecular weight of the polyamideimide-based resin is preferably 100,000 or more, more preferably 150,000 or more, even more preferably 210,000 or more, even more preferably 250,000 or more, particularly preferably 300,000 or more, preferably 500,000 or less, More preferably, it is 450,000 or less, More preferably, it is 400,000 or less. The larger the weight average molecular weight of the polyamideimide-based resin, the easier it is to express the elastic modulus and the flex resistance when the film is formed. For this reason, it is preferable that a weight average molecular weight is more than the said minimum from a viewpoint of easily increasing the elasticity modulus and bending resistance of an optical film. On the other hand, the smaller the weight average molecular weight of the polyamide-imide-based resin, the easier the viscosity of the varnish is to be, and the tendency is to tend to improve the workability. Moreover, there exists a tendency for the stretchability of polyamide-imide type resin to improve easily. For this reason, from a viewpoint of workability and stretchability, it is preferable that a weight average molecular weight is below the said upper limit. In addition, in this application, a weight average molecular weight can carry out gel permeation chromatography (GPC) measurement, and it can calculate | require by standard polystyrene conversion, For example, it can calculate by the method as described in an Example.

The imidation ratio of the polyamide-imide resin is preferably 95 to 100%, more preferably 97 to 100%, still more preferably 98 to 100%, particularly preferably 100%. It is preferable that the imidation ratio is more than the said minimum from a viewpoint of the stability of a varnish and the mechanical physical property of the optical film obtained. In addition, the imidation ratio can be calculated | required by IR method, NMR method, etc. From the said viewpoint, it is preferable that the imidation ratio of the polyamide-imide-type resin contained in a varnish exists in the said range.

In one preferable embodiment of the present invention, the polyamide-imide resin contained in the optical film of the present invention can be introduced by, for example, the fluorine-containing substituent described above. When the polyamide-imide resin contains a halogen atom, the elastic modulus and the flex resistance of the optical film are maintained at a high level, and yellowness (YI value) is easily reduced. When the elastic modulus and the bending resistance of the optical film are high, it is easy to suppress the occurrence of scratches and wrinkles in the film, and when the yellowness of the optical film is low, the transparency of the film is easily improved. The halogen atom is preferably a fluorine atom. As a preferable fluorine-containing substituent in order to contain a fluorine atom in polyamide-imide-type resin, a fluoro group and a trifluoromethyl group are mentioned, for example.

When the polyamideimide resin has a halogen atom, the content thereof is preferably 1 to 40% by mass, more preferably 5 to 40% by mass, and even more, based on the mass of the polyamideimide resin. Preferably it is 5-30 mass%. When content of a halogen atom is 1 mass% or more, the elasticity modulus and bending resistance at the time of film-forming are further improved, water absorption is reduced, yellowness (YI value) is further reduced, and transparency is easy to improve more. When content of a halogen atom exceeds 40 mass%, synthesis may become difficult.

In the polyamideimide-based resin in the present invention, the content of the structural unit represented by Formula (13) is preferably 0.1 mol or more, more preferably 0.5 to 1 mol of the structural unit represented by Formula (10). It is more than 1 mol, More preferably, it is 1.0 mol or more, Especially preferably, it is 1.5 mol or more, Preferably it is 6.0 mol or less, More preferably, it is 5.0 mol or less, More preferably, it is 4.5 mol or less. When content of the structural unit represented by Formula (13) is more than the said minimum, it is easy to express high surface hardness, bending resistance, and low yellowness. Moreover, when content of the structural unit represented by Formula (13) is below the said upper limit, the thickening by the hydrogen bond between the amide bonds in Formula (13) can be suppressed, and the viscosity of a resin varnish can be reduced and manufacture of an optical film It is easy.

In one Embodiment of this invention, content of the polyamide-imide-type resin in an optical film becomes like this. Preferably it is 40 mass% or more, More preferably, it is 50 mass% or more based on the total mass of an optical film. More preferably, it is 70 mass% or more. It is preferable that content of polyamide-imide resin is more than the said minimum from a viewpoint of easy to raise elasticity modulus, flex resistance, etc. In addition, content of polyamide-imide-type resin in an optical film is 100 mass% or less normally on the basis of the total mass of an optical film.

<Silica Particles>

It is preferable that the optical film of this invention contains a silica particle. It exists in the tendency for the elasticity modulus of an optical film to improve more by containing a silica particle. In addition, from the viewpoint of easily reducing the yellowness (YI) of the optical film, silica particles (may be referred to as methoxy modified silica particles) in which methoxy groups are bonded (or substituted) in whole or in part can be suitably used. . Such a methoxy-modified silica particle can be contained in an optical film by using the silica sol (it may be called methanol dispersion silica sol) which uses methanol as a dispersion medium in the solvent substitution process of the optical film mentioned later. . In addition, by using methanol-dispersed silica sol as a raw material, by containing methoxy-modified silica particles in the optical film, the intensity ratio (A / B) can be adjusted to 0.02 or more, and low yellowness (YI value) and high modulus of elasticity The optical film which has is obtained. The yellowness (YI value) of the optical film is reduced in this way because the silicon (Si) atoms of the silica particles contained in the optical film are modified by a methoxy group of a predetermined amount or more, resulting in the hydrophobicity improvement on the surface of the silica particles. And affinity of polyamide-imide-based resin increase, and it is presumably because silica particles are easily dispersed uniformly in the optical film. In addition, since the methoxy ionic strength (A) measured by the TOF-SIMS method is estimated to be derived from a methoxy group or methanol, and the silicon ionic strength (B) is derived from a silicon atom, the adjustment of the strength ratio is methanol. It is not limited to the adjustment using a dispersion silica as a raw material, You may adjust and adjust content, such as a compound containing a Si atom, a compound containing a methoxy group, methanol.

The primary particle diameter of the silica particles is preferably 5 nm or more, more preferably 7 nm or more, even more preferably 10 nm or more, preferably 30 nm or less, more preferably 27 nm or less, even more preferably 25 nm or less, and these upper limits. Combinations of and lower limits may be used. If the primary particle of a silica particle is more than the said minimum, it will tend to suppress aggregation of a silica particle, to reduce a yellowness (YI value), and to have high bending resistance. If it is below the said upper limit, it will be easy to improve transparency of a film. In addition, the primary particle diameter of a silica particle can be measured by BET method. In addition, you may measure the primary particle diameter (average primary particle diameter) of a silica particle by the image analysis of a transmission electron microscope (TEM) and a scanning electron microscope (SEM).

The content of the silica particles is preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less, particularly preferably 33% by mass or less, particularly 30, based on the mass of the optical film. It is mass% or less, Preferably it is 1 mass% or more, More preferably, it is 3 mass% or more, More preferably, it is 5 mass% or more, Especially preferably, it is 10 mass% or more, The combination of these upper limits and a minimum may be sufficient. If content of a silica particle is the said range, it will be easy to improve elasticity modulus and flex resistance, and the optical film with high elastic modulus and flex resistance will be easy to be obtained. Moreover, the addition amount of a silica particle can be adjusted suitably, and the said intensity ratio (A / B) can also be adjusted in the scope of the present invention.

The optical film of this invention may contain the filler. As a filler, organic particle | grains, an inorganic particle, etc. are mentioned, for example, Especially an inorganic particle is preferable. As inorganic particles, metal fluorides such as zirconia, alumina, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), metal oxide particles such as antimony oxide and cerium oxide, magnesium fluoride and sodium fluoride Particles etc. are mentioned, These filler can be used individually or in combination of 2 or more types.

The optical film of this invention may contain the additive other than the said polyamide-imide-type resin, the said silica particle, and the said filler. As another additive, a leveling agent, antioxidant, a ultraviolet absorber, a bluing agent, a plasticizer, surfactant, etc. are mentioned, for example. These other additives can be used individually or in combination of 2 or more types. When an optical film contains another additive, content of another additive may be 0.01-20 mass parts with respect to the mass of an optical film, for example, Preferably it is about 0.1-10 mass parts.

[Method of Manufacturing Optical Film]

One embodiment about the manufacturing method of the optical film of this invention is shown below.

The manufacturing method of the optical film of this invention can include the process (solvent substitution process) of solvent-substituting a methanol dispersion silica sol. Moreover, the process (varnish preparation process) of mixing a solvent-substituted silica sol and polyamide-imide-type resin may be included. Moreover, the process of apply | coating the said varnish obtained by the varnish preparation process to a base material, and forming a coating film can be included. It may also include a step (optical film forming step) of drying the applied liquid (the coating film) to form an optical film.

A solvent substitution process is a process of solvent substitution of methanol which is a dispersion medium of methanol dispersion silica sol with another solvent. As another solvent, what is necessary is just a solvent higher boiling point than methanol, For example, what was illustrated as a solvent used for preparation of the varnish mentioned later is mentioned. Among these, the solvent whose boiling point is 100 degreeC or more is preferable from a viewpoint of the ease of solvent substitution, and it is more preferable to use the same solvent as the solvent used for varnish preparation mentioned later from the viewpoint of the ease of varnish preparation. Moreover, solid content concentration of a methanol dispersion silica sol is 5-50 mass%, for example, Preferably it is 15-40 mass%.

Methanol-dispersed silica sol which is a raw material may be obtained by solvent-substituting a water-dispersed aqueous silica sol with methanol, and may use a commercial item. As a commercial item, Nissan Chemical Co., Ltd. brand name "MA-ST-S" (methanol dispersion silica sol), brand name "MT-ST" (methanol dispersion silica sol), brand name "MA-ST- UP "(methanol dispersion silica sol), brand name" MA-ST-M "(methanol dispersion silica sol), brand name" MA-ST-L "(methanol dispersion silica sol), brand name" MA-ST-G-ML1 "( Methanol dispersion silica sol), and the like. In addition, the methanol dispersion silica sol may contain solvents, such as alcohol other than methanol.

In the solvent substitution step, the other solvent is evaporated while adding or adding another solvent to the methanol dispersed silica sol. The solvent substitution may be performed under vacuum, under reduced pressure, or under normal pressure, or under normal temperature or heating, but under reduced pressure, from the viewpoint of suppressing aggregation of silica particles and easily obtaining a dispersion medium in which silica particles are uniformly dispersed, For example, it is preferable to carry out at 40-80 degreeC. In a solvent substitution process, when using methanol dispersion silica sol, the said intensity ratio (A / B) of the optical film obtained is easy to adjust to 0.02 or more, and yellowness (YI value) is easy to be reduced. Moreover, solid content concentration of a solvent-substituted silica sol is 5-50 mass%, for example, Preferably it is 15-40 mass%.

In the varnish preparation step, the varnish is dissolved by dissolving a polyamideimide resin in a solvent and stirring and mixing the polyamideimide resin dissolved in the solvent with the solvent-substituted silica sol and, if necessary, the filler or the other additives. To prepare.

The solvent used for preparation of the varnish is not particularly limited as long as the resin can be dissolved. As such a solvent, For example, 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. Among these, an amide solvent or a lactone solvent is preferable. These solvents can be used individually or in combination of 2 or more types. The varnish may include water, an alcohol solvent, a ketone solvent, an acyclic ester solvent, an ether solvent, or the like. Solid content concentration of a varnish becomes like this. Preferably it is 1-25 mass%, More preferably, it is 5-15 mass%.

In a coating process, a varnish is apply | coated on a base material by a well-known coating method, and a coating film is formed. As a well-known coating method, for example, a roll coating method such as wire bar coating method, reverse coating, gravure coating, die coating method, comma coating method, lip coating method, spin coating method, screen coating method, fountain coating method, A ping method, a spray method, the casting molding method, etc. are mentioned.

In an optical film formation process, an optical film can be formed by drying a coating film and peeling from a base material. You may perform the drying process which dries an optical film further after peeling. Drying of a coating film can be performed at the temperature of 50-350 degreeC normally. As needed, you may dry a coating film in inert atmosphere or pressure-reduced conditions.

As an example of a base material, a PET film, a PEN film, another polyimide resin, a polyamide resin film, etc. are mentioned. Especially, a PET film, a PEN film, etc. are preferable from a viewpoint of excellent heat resistance, and PET film is more preferable from a viewpoint of adhesiveness with an optical film, and cost.

The use of the optical film of this invention is not specifically limited, You may use for various uses. As demonstrated above, the optical film of this invention may be a single | mono layer, and the laminated body which laminated | stacked the some optical film of this invention may be sufficient. Moreover, you may use the optical film of this invention of a single layer as it is, and may use as a laminated body with another film. In addition, when an optical film is a laminated body, all the layers laminated | stacked on the single side | surface or both surfaces of an optical film are called an optical film.

When the optical film of this invention is a laminated body, it is preferable to have one or more functional layers in at least one surface of an optical film. As a functional layer, an ultraviolet absorber layer, a primer layer, a gas barrier layer, an adhesion layer, a color adjustment layer, a refractive index adjustment layer, a hard coat layer, etc. are mentioned, for example. A functional layer can be used individually or in combination of 2 or more types.

The ultraviolet absorbing layer is a layer having a function of absorbing ultraviolet rays, and is composed of, for example, a main material selected from an ultraviolet curable transparent resin, an electron beam curable transparent resin, and a thermosetting transparent resin, and a ultraviolet absorber dispersed in the main material. do.

An adhesive layer is a layer which has a sticky function, and has a function which adhere | attaches an optical film to another member. As a formation material of an adhesion layer, a conventionally well-known thing can be used. For example, a thermosetting resin composition or a photocurable resin composition can be used. In this case, the thermosetting resin composition or the photocurable resin composition can be polymerized and cured by supplying energy afterwards.

The pressure-sensitive adhesive layer may be a layer adhered to the object by pressure, called a pressure sensitive adhesive (PSA). The pressure-sensitive adhesive may be an adhesive which is "a substance which has adhesiveness at room temperature and adheres to the adherend at light pressure" (JIS K 6800), and "contains a specific component in a protective film (microcapsule), and adopts suitable means (pressure Or an adhesive capable of holding stability until the film is destroyed by heat, or the like '' (JIS K 6800).

A color adjustment layer is a layer which has a function of color adjustment, and is a layer which can adjust an optical film to a target color. A color adjustment layer is a layer containing resin and a coloring agent, for example. As this coloring agent, For example, inorganic pigments, such as titanium oxide, zinc oxide, a bengalah, a titanium oxide type | system | group baking pigment, ultramarine blue, cobalt aluminate, and carbon black; Organic pigments such as azo compounds, quinacridone compounds, anthraquinone compounds, perylene compounds, isoindolinone compounds, phthalocyanine compounds, quinophthalone compounds, styrene compounds, and diketopyrrolopyrrole compounds; Extender pigments such as barium sulfate and calcium carbonate; And dyes such as basic dyes, acid dyes, and mordant dyes.

A refractive index adjustment layer is a layer which has a function of refractive index adjustment, for example, is a layer which has a refractive index different from a single optical film, and can give a predetermined refractive index to an optical film. The refractive index adjusting layer may be, for example, a resin that is appropriately selected, and a resin layer further containing a pigment as the case may be, or a thin film of metal. As a pigment which adjusts a refractive index, silicon oxide, aluminum oxide, antimony oxide, tin oxide, titanium oxide, zirconium oxide, and tantalum oxide are mentioned, for example. The average primary particle diameter of the said pigment may be 0.1 micrometer or less. By making the average primary particle diameter of a pigment into 0.1 micrometer or less, the diffuse reflection of the light which permeate | transmits a refractive index adjustment layer can be prevented, and the fall of transparency can be prevented. Examples of the metal used for the refractive index adjusting layer include titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, silicon nitride, and the like. Metal oxides or metal nitrides.

The hard coating layer can be formed by curing a hard coating composition containing a reactive material capable of forming a crosslinked structure by active energy ray irradiation or thermal energy application, and preferably by active energy ray irradiation. Active energy rays are defined as energy rays capable of decomposing compounds that generate active species to generate active species, and include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays, and electron rays. And preferably ultraviolet rays. The hard coating composition contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound.

The said radically polymerizable compound is a compound which has a radically polymerizable group. As a radically polymerizable group which the said radically polymerizable compound has, what is necessary is just a functional group which can generate | occur | produce a radical polymerization reaction, The group containing a carbon-carbon unsaturated double bond, etc. are mentioned, Specifically, a vinyl group and (meth) acryl Royl group etc. are mentioned. In addition, when the said radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be same or different, respectively. The number of radically polymerizable groups which the radically polymerizable compound has in one molecule is preferably two or more in terms of improving the hardness of the hard coat layer. As said radically polymerizable compound, From the point of reactivity high, Preferably, the compound which has a (meth) acryloyl group is mentioned, Specifically, it has 2-6 (meth) acryloyl groups in 1 molecule. Oligomers having a molecular weight of several hundred to several thousand having several (meth) acryloyl groups in a compound called a functional acrylate monomer or a molecule called an epoxy (meth) acrylate, a urethane (meth) acrylate or a polyester (meth) acrylate. These are mentioned, Preferably, 1 or more types chosen from an epoxy (meth) acrylate, a urethane (meth) acrylate, and polyester (meth) acrylate is mentioned.

The said cationically polymerizable compound is a compound which has cationically polymerizable groups, such as an epoxy group, an oxetanyl group, and a vinyl ether group. The number of the cationically polymerizable groups which the cationically polymerizable compound has in one molecule is preferably 2 or more, more preferably 3 or more, from the point of improving the hardness of the hard coat layer.

Moreover, as said cationically polymerizable compound, the compound which has at least 1 sort (s) of an epoxy group and an oxetanyl group as a cationically polymerizable group is especially preferable. Cyclic ether groups, such as an epoxy group and an oxetanyl group, are preferable at the point that shrinkage accompanying a polymerization reaction is small. Moreover, the compound which has an epoxy group in a cyclic ether group is easy to acquire the compound of various structures, does not adversely affect the durability of the obtained hard coat layer, and also has the advantage that it is easy to control compatibility with a radically polymerizable compound. have. In addition, the oxetanyl group in the cyclic ether group tends to have a high degree of polymerization compared to the epoxy group, is low toxicity, and speeds up the network formation rate obtained from the cationically polymerizable compound of the obtained hard coat layer, and is unreacted even in a region mixed with the radically polymerizable compound. There is an advantage of forming an independent network without leaving the monomer in the film.

As a cationically polymerizable compound which has an epoxy group, for example, the polyglycidyl ether or cyclohexene ring of a polyhydric alcohol which has an alicyclic ring, and a cyclopentene ring containing compound are epoxidized by suitable oxidizing agents, such as hydrogen peroxide and peracid, for example. Alicyclic epoxy resin obtained by; Aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyhydric alcohols or alkylene oxide adducts thereof, polyglycidyl esters of aliphatic long-chain polybasic acids, homopolymers of glycidyl (meth) acrylates, and copolymers; Glycidyl ether produced by reaction of bisphenols, such as bisphenol A, bisphenol F, hydrogenated bisphenol A, or derivatives, such as alkylene oxide adducts and caprolactone adducts, and epichlorohydrin, and furnace And glycidyl ether type epoxy resins derived from bisphenols.

The hard coating composition may further include a polymerization initiator. As a polymerization initiator, a radical polymerization initiator, a cationic polymerization initiator, a radical and a cationic polymerization initiator, etc. are mentioned, It selects suitably and is used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to advance radical polymerization and cationic polymerization.

The radical polymerization initiator should just be able to discharge | release the substance which starts radical polymerization by at least any one of active energy ray irradiation and heating. For example, azo compounds, such as organic peroxides, such as hydrogen peroxide and a perbenzoic acid, azobisbutyronitrile, etc. are mentioned as a thermal radical polymerization initiator.

As active energy ray radical polymerization initiators, there are Type 1 type radical polymerization initiators in which radicals are generated by the decomposition of molecules, and Type 2 type radical polymerization initiators which coexist with tertiary amines to generate radicals by hydrogen drawing reactions. Or in combination.

The cationic polymerization initiator may be capable of releasing a substance for initiating cationic polymerization by at least one of active energy ray irradiation and heating. As a cationic polymerization initiator, an aromatic iodonium salt, an aromatic sulfonium salt, a cyclopentadienyl iron (II) complex, etc. can be used. These can start cationic polymerization by active energy ray irradiation, heating, or both according to a difference in structure.

Content of the said polymerization initiator becomes like this. Preferably it is 0.1-10 mass% with respect to 100 mass% of whole said hard coat compositions. When content of the said polymerization initiator exists in the said range, hardening can fully advance and the mechanical property and adhesive force of the coating film finally obtained can be made into a favorable range, and the adhesive force defect, a crack phenomenon, and a curl phenomenon by hardening shrinkage can be made. This tends to be difficult to occur.

The hard coating composition may further include one or more selected from the group consisting of a solvent and an additive.

The said solvent can melt | dissolve or disperse the said polymeric compound and a polymerization initiator, and if it is a solvent known as a solvent of the hard-coating composition of this art, it can be used in the range which does not impair the effect of this invention.

The additive may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents and the like.

The thickness of a hard coat layer is not specifically limited, For example, 2-100 micrometers may be sufficient. When the thickness of the hard coat layer is in the above range, sufficient scratch resistance can be ensured, and the flex resistance is hardly lowered, and the problem of curl generation due to curing shrinkage tends to be less likely to occur.

The optical film may further contain the protective film. The protective film may be laminated on one side or both sides of the optical film. When having a functional layer in the single side | surface of an optical film, a protective film may be laminated | stacked on the surface of the optical film side, or the surface of the functional layer side, and may be laminated | stacked on both the optical film side and the functional layer side. When it has a functional layer on both surfaces of an optical film, a protective film may be laminated | stacked on the surface of one functional layer side, and may be laminated | stacked on the surface of both functional layer sides. A protective film is a film for temporarily protecting the surface of an optical film or a functional layer, and it is not specifically limited as long as it is a peelable film which can protect the surface of an optical film or a functional layer. As a protective film, For example, Polyester-based resin films, such as polyethylene terephthalate, a polybutylene terephthalate, a polyethylene naphthalate; Polyolefin resin films, such as polyethylene and a polypropylene film, an acrylic resin film, etc. are mentioned, It is preferable to select from the group which consists of a polyolefin resin film, a polyethylene terephthalate resin film, and an acrylic resin film. When an optical film has two protective films, each protective film may be same or different.

Although the thickness of a protective film is not specifically limited, Usually, 10-100 micrometers, Preferably it is 10-80 micrometers, More preferably, it is 10-50 micrometers. When an optical film has two protective films, the thickness of each protective film may be same or different.

Since the optical film of this invention contains the said polyamide-imide-type resin and the said intensity | strength ratio (A / B) is 0.02 or more, low yellowness and high elastic modulus can be compatible. For this reason, it can use suitably as an optical film in an image display apparatus etc. The optical film of the present invention is preferably useful as a front plate of an image display device, particularly as a front plate (window film) of a flexible image display device (flexible display). The flexible display has, for example, a flexible functional layer and an optical film laminated on the flexible functional layer to function as a front plate. That is, the front panel of the flexible display is arranged on the viewer side on the flexible functional layer. This front plate has a function of protecting the flexible functional layer.

Examples of the image display apparatus include wearable devices such as televisions, smartphones, cellular phones, car navigation systems, tablet PCs, portable game machines, electronic papers, indicators, bulletin boards, watches, and smart watches. As a flexible display, it is a general image display apparatus which has a flexible characteristic.

[Flexible Image Display]

This invention includes the flexible image display apparatus provided with the optical film of this invention. As mentioned above, the optical film of this invention is preferably used as a front plate in a flexible image display apparatus, and the said front plate may be called a window film. The flexible image display device consists of a laminated body for flexible image display apparatuses, and an organic electroluminescent display panel, The flexible image display apparatus laminated body is arrange | positioned at the visual recognition side with respect to an organic electroluminescent display panel, and is comprised so that it is bendable. As a laminated body for flexible image display apparatuses, you may contain the window film, a polarizing plate, and a touch sensor, and the lamination order is arbitrary, but the order of a window film, a polarizing plate, a touch sensor or a window film, a touch sensor, and a polarizing plate from the visual recognition side. It is preferable that it is laminated | stacked. When a polarizing plate exists in the visual recognition side of a touch sensor, since the pattern of a touch sensor becomes difficult to see and the visibility of a display image becomes favorable, it is preferable. Each member can be laminated | stacked using an adhesive agent, an adhesive, etc. The light shielding pattern may be provided on at least one surface of any one of the window film, the polarizing plate, and the touch sensor.

[Polarizing Plate]

The flexible image display device of the present invention contains a polarizing plate, preferably a circular polarizing plate, as described above. The circularly polarizing plate is a functional layer having a function of transmitting only right circularly polarized light or left circularly polarized light component by laminating a? / 4 phase difference plate on a linear polarizing plate. For example, it is used to convert external light into right circularly polarized light to block external light reflected by the organic EL panel and become left circularly polarized light, and to transmit only the light emitting components of the organic EL to suppress the influence of the reflected light to make the image easier to see. In order to achieve the circularly polarized light function, the absorption axis of the linear polarizing plate and the slow axis of the λ / 4 phase difference plate need to be 45 ° in theory, but are practically 45 ± 10 °. The linear polarizer and the λ / 4 retardation plate do not necessarily have to be stacked adjacent to each other, and the relationship between the absorption axis and the slow axis may satisfy the range described above. Although it is preferable to achieve complete circularly polarized light in the electric wave field, the circularly polarized plate in the present invention also includes an elliptical polarizing plate because it is not necessarily necessary. It is also preferable to improve the visibility in the state over polarized sunglasses by laminating | stacking (lambda) / 4 phase (s) difference film further on the visual recognition side of a linear polarizing plate, and making outgoing light circularly polarized.

The linear polarizer is a functional layer having a function of passing light that vibrates in the transmission axis direction but blocking polarization of a vibration component perpendicular to the linear polarizer. The linear polarizing plate may be a structure including a linear polarizer alone or a linear polarizer and a protective film attached to at least one surface thereof. The thickness of the linear polarizing plate may be 200 μm or less, and preferably 0.5 to 100 μm. When thickness exists in the said range, it exists in the tendency for flexibility to fall easily.

The linear polarizer may be a film polarizer manufactured by dyeing and stretching a polyvinyl alcohol (PVA) film. A dichroic dye is orientated and exhibits polarization performance by extending | stretching in the state which the dichroic dye, such as iodine, adsorbed or adsorb | sucked to PVA to the PVA system film oriented by extending | stretching. In manufacture of the said film polarizer, you may have other processes, such as swelling, bridge | crosslinking by boric acid, washing | cleaning by aqueous solution, and drying. The stretching or dyeing step may be performed by a PVA film alone, or may be performed in a state of being laminated with other films such as polyethylene terephthalate. Preferably the thickness of the PVA system film used is 10-100 micrometers, and draw ratio is 2-10 times preferably.

Moreover, as another example of the said polarizer, the liquid crystal coating type polarizer formed by apply | coating and forming a liquid crystal polarizing composition may be sufficient. The liquid crystal polarizing composition may include a liquid crystal compound and a dichroic dye compound. The said liquid crystalline compound should just have the property to show a liquid crystal state, and especially since it can exhibit high polarization performance, if it has high order orientation states, such as a smectic phase, it is preferable. Moreover, it is also preferable that a liquid crystalline compound has a polymeric functional group.

The said dichroic dye is a pigment | dye which orientates together with the said liquid crystal compound, and shows dichroism, The dichroic dye itself may have liquid crystallinity, and may have a polymeric functional group. Certain compounds in the liquid crystal polarizing composition have a polymerizable functional group.

The liquid crystal polarizing composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like.

The said liquid crystal polarizing layer is manufactured by apply | coating a liquid crystal polarizing composition on an oriented film, and forming a liquid crystal polarizing layer.

The liquid crystal polarizing layer can be formed thinner than the film type polarizer. Preferably the thickness of the said liquid crystal polarizing layer may be 0.5-10 micrometers, More preferably, 1-5 micrometers may be sufficient.

The said orientation film can be manufactured by apply | coating an orientation film formation composition on a base material, for example, and providing orientation by rubbing, polarized light irradiation, etc. The alignment film forming composition may contain a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, or the like in addition to the alignment agent. As said aligning agent, polyvinyl alcohol, polyacrylates, polyamic acid, polyimide can be used, for example. When applying photo-alignment, it is preferable to use the aligning agent containing a cinnamate group. The weight average molecular weight of the polymer used as the aligning agent may be about 10,000 to 1,000,000. The thickness of the alignment film is preferably 5 to 10,000 nm, more preferably 10 to 500 nm from the viewpoint of the orientation regulation force. The liquid crystal polarizing layer may be peeled off from the substrate, transferred and laminated, or the substrate may be laminated as it is. It is also preferable that the said base material plays a role as a transparent base material of a protective film, a retardation plate, and a window.

As said protective film, what is necessary is just a transparent polymer film, and the material and additive used for the said transparent base material can be used. Cellulose films, olefin films, acrylic films and polyester films are preferred. The coating type protective film obtained by apply | coating and hardening radical hardening compositions, such as a cation hardening composition, such as an epoxy resin, and an acrylate, may be sufficient. If necessary, plasticizers, ultraviolet absorbers, infrared absorbers, coloring agents such as pigments and dyes, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, lubricants, solvents, and the like may be included. The thickness of the said protective film may be 200 micrometers or less, Preferably it is 1-100 micrometers. When the thickness of the said protective film exists in said range, the flexibility of a protective film will not fall easily. A protective film can also serve as the transparent base material of a window.

The said (lambda) / 4 phase (s) difference plate is a film which gives the phase difference of (lambda) / 4 in the direction orthogonal to the advancing direction of incident light (in-plane direction of a film). The lambda / 4 retardation plate may be a stretchable retardation plate produced by stretching a polymer film such as a cellulose film, an olefin film, a polycarbonate film or the like. If necessary, a phase difference regulator, a plasticizer, an ultraviolet absorber, an infrared absorber, a coloring agent such as a pigment or a dye, a fluorescent brightener, a dispersant, a thermal stabilizer, a light stabilizer, an antistatic agent, an antioxidant, a lubricant, a solvent, and the like may be included. The thickness of the said stretchable phase difference plate may be 200 micrometers or less, Preferably it is 1-100 micrometers. When thickness exists in the said range, there exists a tendency for the flexibility of a film to fall easily.

Moreover, as another example of the said (lambda) / 4 phase (s) difference plate, the liquid crystal coating type phase difference plate formed by apply | coating and forming a liquid crystal composition may be sufficient. The said liquid crystal composition contains the liquid crystalline compound which has the property to show liquid crystal states, such as nematic, cholesteric, and smectic. Certain compounds containing the liquid crystalline compound in the liquid crystal composition have a polymerizable functional group. The liquid crystal coating type retardation plate may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The said liquid crystal coating type phase difference plate can be manufactured by apply | coating and hardening a liquid crystal composition on an orientation film similarly to the base material in the said liquid crystal polarizing layer, and forming a liquid crystal phase difference layer. The liquid crystal coating retardation plate can be formed thinner than the stretchable retardation plate. The thickness of the liquid crystal polarizing layer is usually 0.5 to 10 m, preferably 1 to 5 m. The liquid crystal coating type retardation plate may be peeled off from the substrate, transferred and laminated, or the substrate may be laminated as it is. It is also preferable that the base material serves as a transparent base material of a protective film, a retardation plate, and a window.

In general, the shorter the wavelength, the larger the birefringence, and the longer the wavelength, the more material exhibits the small birefringence. In this case, since the phase difference of λ / 4 cannot be achieved in the full visible region, it is often designed to have an in-plane phase difference of 100 to 180 nm, preferably 130 to 150 nm, which is λ / 4 around 560 nm with high visibility. . It is preferable to use a reverse dispersion lambda / 4 retardation plate using a material having a birefringence wavelength dispersion characteristic opposite to that of normal, since the visibility can be improved. As such a material, it is also preferable to use what is described in Unexamined-Japanese-Patent No. 2010-30979, such as Unexamined-Japanese-Patent No. 2007-232873 in the case of a stretchable retardation plate.

As another method, a technique for obtaining a wideband [lambda] / 4 phase difference plate by combining with a [lambda] / 2 phase difference plate is also known (Japanese Patent Laid-Open No. H10-90521). The lambda / 2 phase difference plate is also manufactured by the same material method as the lambda / 4 phase difference plate. Although the combination of an extending | stretching retardation plate and a liquid crystal coating type retardation plate is arbitrary, it is preferable to use a liquid crystal coating type retardation plate since both can make thickness thin.

A method of laminating a positive C plate is also known in the circular polarizing plate in order to increase visibility in an oblique direction (Japanese Patent Laid-Open No. 2014-224837). The positive C plate may be a liquid crystal coating type retardation plate or a stretched retardation plate. The phase difference in the thickness direction is -200 to -20 nm, preferably -140 to -40 nm.

[Touch sensor]

The flexible image display device of the present invention contains a touch sensor as described above. The touch sensor is used as an input means. As a touch sensor, various forms, such as a resistive film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitive type, are proposed, and what kind of method may be used. Especially, the capacitive system is preferable. The capacitive touch sensor is divided into an active region and an inactive region positioned at an outer portion of the active region. The active area is an area corresponding to an area (display) where a screen is displayed on the display panel. The active area is an area where a user's touch is detected. The inactive area is an area corresponding to an area (non-display area) where a screen is not displayed on the display device. . The touch sensor includes a substrate having a flexible characteristic; A sensing pattern formed in an active region of the substrate; Each sensing line may be formed in an inactive region of the substrate and connected to an external driving circuit through the sensing pattern and the pad unit. As a board | substrate which has a flexible characteristic, the material similar to the transparent substrate of the said window can be used. The toughness of the substrate of the touch sensor is preferably 2,000 MPa% or more in view of crack suppression of the touch sensor. More preferably, the toughness may be 2,000 to 30,000 MPa%. Here, toughness is defined as the lower area of the curve from the stress (MPa) -strain (%) curve to the break point obtained through the tensile test of the polymer material.

The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer, and each pattern must be electrically connected to sense a touched point. The first pattern is a form in which each unit pattern is connected to each other through a seam, but the second pattern has a structure in which each unit pattern is separated from each other in an island form. Thus, in order to electrically connect the second pattern, a separate bridge electrode is provided. need. The sensing pattern may apply a well-known transparent electrode material. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), indium gallium zinc oxide (IGZO), cadmium tin oxide (CTO), PEDOT (poly (3,4-ethylenedioxythiophene)), a carbon nanotube (CNT), graphene, a metal wire, etc. can be mentioned, These can be used individually or in mixture of 2 or more types. Preferably ITO can be used. The metal used for a metal wire is not specifically limited, For example, silver, gold, aluminum, copper, iron, nickel, titanium, selenium, chromium, etc. are mentioned. These can be used individually or in mixture of 2 or more types.

The bridge electrode may be formed on the insulating layer through the insulating layer on the sensing pattern, the bridge electrode is formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrode may be formed of a material such as a sensing pattern, or may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more thereof. have. Since the first pattern and the second pattern must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint of the first pattern and the bridge electrode, or may be formed in a structure of a layer covering the sensing pattern. In the latter case, the bridge electrode can connect the second pattern through the contact hole formed in the insulating layer. The touch sensor is suitable for properly compensating for the difference in light transmittance caused by the difference in transmittance between the patterned pattern region and the non-patterned region in which the pattern is not formed, specifically, the refractive index difference in these regions. An optical control layer may be further included between the substrate and the electrode as a means, and the optical control layer may include an inorganic insulating material or an organic insulating material. The optical control layer may be formed by coating a photocurable composition including a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The inorganic particles may increase the refractive index of the optical control layer.

The photocurable organic binder may include, for example, a copolymer of each monomer such as an acrylate monomer, a styrene monomer, a carboxylic acid monomer, and the like. The said photocurable organic binder may be a copolymer containing each different repeating unit, such as an epoxy group containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit, for example.

The inorganic particles may include, for example, zirconia particles, titania particles, alumina particles, and the like. The said photocuring composition may further contain each additive, such as a photoinitiator, a polymerizable monomer, and a hardening adjuvant.

[Adhesive layer]

Each layer (window, circular polarizing plate, touch sensor) which forms the said laminated body for flexible image display apparatuses, and the film member (linear polarizing plate, (lambda) / 4 phase (s) difference plate, etc.) which comprise each layer can be formed with an adhesive agent. Examples of the adhesive include an aqueous adhesive, an aqueous solvent volatilized adhesive, an organic solvent, a solventless adhesive, a solid adhesive, a solvent volatilized adhesive, a moisture curable adhesive, a heat curable adhesive, an anaerobic curable, an active energy ray curable adhesive, a curing agent mixed adhesive, and a heat. What is used universally can be used, such as a melt adhesive, a pressure-sensitive adhesive (adhesive), and a re-wetting adhesive. Among them, an aqueous solvent volatilized adhesive, an active energy ray curable adhesive, and an adhesive are used well. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive force and the like, and is 0.01 to 500 μm, preferably 0.1 to 300 μm. Although a plurality exists in the laminate for the flexible image display device, the thickness and the type of the adhesive used are It can be the same or different.

As the aqueous solvent volatilized adhesive, a polymer in an aqueous dispersion state such as a polyvinyl alcohol polymer, a water-soluble polymer such as starch, an ethylene-vinyl acetate emulsion, or a styrene-butadiene emulsion can be used as the main polymer. In addition to water and the said main polymer, you may mix | blend a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, antioxidant, dye, a pigment, an inorganic filler, an organic solvent, etc. In the case of adhering with the aqueous solvent volatilized adhesive, the aqueous solvent volatilized adhesive may be injected between the layers to be bonded and bonded to each other, and then the adhesiveness can be imparted by drying. The thickness of the adhesive layer in the case of using the said aqueous solvent volatilization type adhesive agent may be 0.01-10 micrometers, Preferably 0.1-1 micrometer may be sufficient. When using the aqueous solvent volatilized adhesive for forming a plurality of layers, the thickness of each layer and the kind of the adhesive may be the same or different.

The said active energy ray hardening-type adhesive agent can be formed by hardening of the active energy ray hardening composition containing the reactive material which irradiates an active energy ray and forms an adhesive bond layer. The active energy ray-curing composition may contain at least one polymer of a radically polymerizable compound and a cationically polymerizable compound similar to the hard coating composition. The said radically polymerizable compound is the same as that of a hard coating composition, The thing of the same kind as a hard coating composition can be used. As a radically polymerizable compound used for an adhesive layer, the compound which has an acryloyl group is preferable. It is also preferable to include a monofunctional compound in order to lower the viscosity as an adhesive composition.

The said cationically polymerizable compound is the same as that of a hard coat composition, The thing of the same kind as a hard coat composition can be used. As a cationically polymerizable compound used for an active energy ray hardening composition, an epoxy compound is especially preferable. It is also preferable to include a monofunctional compound as the reactive diluent in order to lower the viscosity as the adhesive composition.

The active energy ray composition may further include a polymerization initiator. As a polymerization initiator, it is a radical polymerization initiator, a cationic polymerization initiator, a radical, and a cationic polymerization initiator, etc., and can select suitably and can use. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations to advance radical polymerization and cationic polymerization. In the substrate of the hard coating composition, an initiator capable of initiating at least one of radical polymerization or cationic polymerization by active energy ray irradiation can be used.

The active energy ray curing composition may further include an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion agent, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, an antifoaming agent, an additive, and a solvent. In the case of adhering with the active energy ray-curable adhesive, the active energy ray-curing composition is applied to any one or both of the adherend layers and then bonded, and irradiated with an active energy ray through any one or both adherend layers to cure. It can bond by making it. The thickness of the adhesive layer in the case of using the said active energy ray hardening-type adhesive agent may be 0.01-20 micrometers, Preferably 0.1-10 micrometers may be sufficient. When using the said active energy ray hardening-type adhesive agent for formation of multiple layers, the thickness of each layer and the kind of adhesive agent used may be same or different.

As the pressure-sensitive adhesive, depending on the main polymer, it can be classified into acrylic pressure-sensitive adhesives, urethane pressure-sensitive adhesives, rubber pressure-sensitive adhesives, silicone pressure-sensitive adhesives and the like, and any of them can be used. In addition to a main polymer, you may mix | blend a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, antioxidant, a tackifier, a plasticizer, dye, a pigment, an inorganic filler, etc. to an adhesive. The adhesive layer adhesive layer is formed by melt | dissolving and disperse | distributing each component which comprises the said adhesive in a solvent, obtaining an adhesive composition, and apply | coating this adhesive composition on a base material, and drying. The pressure-sensitive adhesive layer may be directly formed or may be transferred to what is formed on a separate substrate. In order to cover the adhesive surface before adhesion, it is also preferable to use a release film. The thickness of the adhesive layer in the case of using the said adhesive is 1-500 micrometers, Preferably it may be 2-300 micrometers. When using the said adhesive for formation of multiple layers, the thickness of each layer and the kind of adhesive used may be same or different.

[Shading Pattern]

The light shielding pattern may be applied as at least part of a bezel or a housing of the flexible image display device. The visibility of an image improves by blocking the wiring arrange | positioned at the margin part of the said flexible image display apparatus by a light shielding pattern, and making it hard to see. The light shielding pattern may be in the form of a single layer or a multilayer. The color of the light shielding pattern is not particularly limited and may have various colors such as black, white, and metal color. The light shielding pattern may be formed of a pigment for realizing color and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, and silicone. You may use these individually or in mixture of 2 or more types. The light shielding pattern can be formed by various methods such as printing, lithography, inkjet, and the like. The thickness of a light shielding pattern is 1-100 micrometers normally, Preferably it is 2-50 micrometers. Moreover, it is also preferable to provide shapes, such as an inclination, in the thickness direction of an optical pattern.

Example

Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example. "%" And "part" in an example mean a mass% and a mass part unless there is particular notice. First, the measurement and evaluation method will be described.

<Primary particle diameter of silica particle>

The primary particle diameter of the silica particle in an Example and a comparative example was measured and evaluated by the BET method.

Haze

In accordance with JIS K 7136: 2000, the optical film obtained by the Example and the comparative example is cut | disconnected to the magnitude | size of 30 mm x 30 mm, and it is made by Haze Computer (Suga Test Instruments Co., Ltd., "HGM -2DP ') and the haze (%) was measured.

Yellow (YI value)

The yellowness (Yellow Index: YI value) of the optical film obtained by the Example and the comparative example was measured using the ultraviolet visible near-infrared spectrophotometer "V-670" by the Japan spectrometer. After background measurement in the absence of a sample, the optical film is set in a sample holder, the transmittance measurement for light of 300 to 800 nm is performed, and tristimulus values (X, Y, Z) are obtained. The YI value was calculated.

YI = 100 × (1.2769X-1.0592Z) / Y

<Light transmittance>

In accordance with JIS K7361-1: 1997, the optical film obtained by the Example and the comparative example was cut | disconnected to the magnitude | size of 30 mm x 30 mm, and it used the haze computer (made by Suga Tester Co., Ltd., "HGM-2DP") The total light transmittance (%) in 50 micrometers in thickness of the film was measured.

<Elastic rate>

The optical film obtained by the Example and the comparative example was cut | disconnected to 10 mm x 100 mm single-sheet shape using the dumbbell cutter, and the sample was obtained. The elasticity modulus of this sample was measured by the Autograph AG-IS by Shimadzu Corporation, and SS curve was measured on condition of the distance between the chuck to 500 mm and the tensile speed 20 mm / min, and the elastic modulus (GPa) of the optical film was calculated from the inclination. did.

<Flexibility Evaluation>

Using a bending tester DLDM111LH manufactured by Yuasa System Co., Ltd., a repeated bending test was performed under conditions of a bending radius (curvature radius) R = 1 mm and 1 Hz. The number of reciprocation bends until a crack generate | occur | produced in an optical film was measured, and the said number of bending was made into the number of bendings. If it was not cracked by 200,000 bendings, it was set as 200,000 times or more.

<Measurement by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)>

The cross section of the optical film was produced using "ultra microtome EM UC6" by Leica Microsystems.

The cross section of the produced resin film was analyzed by TOF-SIMS. The TOF-SIMS apparatus and measurement conditions used for the analysis are as follows.

(1) Apparatus: `` TOF-SIMS V '' manufactured by ION-TOF,

(2) Primary ion: Bi ³⁺

(3) acceleration voltage of primary ion: 25kV

(4) irradiation ion current: 0.23pA

(5) Measurement conditions: Positive and negative ions are measured in bunching (high mass resolution) mode.

(6) Measurement range: 200 μm × 200 μm.

SurfaceLab used TOF-SIMS data analysis. Mass calibration of the measurement data was performed, and the integral value of the peak was computed about each peak which belongs to a methoxy (MeOH) ion and a silicon (Si) ion. To the integral of the CH ₃ O ion peak of the integral of the peak of the detected intensity A, Si ions of CH ₃ O ion in detection strength B of the Si ions, and the strength was calculated a ratio A / B.

<Weight average molecular weight (Mw)>

Gel Permeation Chromatography (GPC) Measurement

Pretreatment method

To the polyamideimide obtained in the Examples and Comparative Examples, DMF eluent (10 mM lithium bromide solution) was added to a concentration of 2 mg / mL, heated at 80 ° C. for 30 minutes with stirring, cooled, and filtered with a 0.45 μm membrane filter. The measurement solution.

·Measuring conditions

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

Eluent: DMF (with 10 mM lithium bromide)

Flow rate: 1.0 mL / min.

Detector: RI Detector

Column temperature: 40 ℃

Injection volume: 100 μL

Molecular Weight Standard: Standard Polystyrene

<Thickness of Optical Film>

The thickness of the optical film was measured for the optical film obtained by the Example and the comparative example using ABS digital indicator ("ID-C112BS" by Mitutoyo Corporation).

Example 1

(Preparation of Silica Sol)

517.2 g of methanol-dispersed silica sol ("MA-ST-M" manufactured by Nissan Chemical Corporation), primary particle size 23 nm, silica particle solid content 40.6%) in a 1000 mL flask and γ-butyrolactone (GBL) ) 490.9 g was added, and methanol was evaporated for 1 hour at 400 hPa and 250 hPa for 1 hour under a hot water bath at 45 ° C with a vacuum evaporator. Furthermore, it heated up to 70 degreeC under 250 hPa, and heated for 30 minutes, and obtained (gamma) -butyrolactone dispersion silica sol 1 (GBL dispersion silica sol 1). Solid content concentration of obtained GBL dispersion silica sol 1 was 29.8%.

(Preparation of polyamideimide)

45 g (140.52 mmol) of 2,2'-bis (trifluoromethyl) -4,4'-diaminodiphenyl (TFMB) and N, N in a 1 L separable flask with a stirring blade under a nitrogen gas atmosphere 768.55 g of dimethylacetamide (DMAc) was added and TFMB dissolved in DMAc with stirring at room temperature. Next, 18.92 g (42.58 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, 4.19 g (14.19 mmol) of 4,4'-oxybis (benzoyl chloride) (OBBC) was added to the flask, followed by 17.29 g (85.16 mmol) of terephthaloyl chloride (TPC), followed by stirring at room temperature for 1 hour. Subsequently, 4.63 g (49.68 mmol) of 4-methylpyridine and 13.04 g (127.75 mmol) of acetic anhydride were added to the flask, and the mixture was stirred at room temperature for 30 minutes, then heated 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, poured into a large amount of methanol at a temperature, and the precipitate which precipitated was taken out, and after immersing in methanol for 6 hours, it wash | cleaned with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain polyamideimide 1. The weight average molecular weight of the obtained polyamideimide 1 was 400,000.

(Manufacture of optical film)

Polyamideimide 1 was dissolved in GBL, the GBL dispersed silica sol 1 was added, and the mixture was sufficiently mixed to obtain a polyamideimide 1 / silica particle mixed varnish. The ratio of polyamideimide 1 and silica particles was 70:30. Moreover, it prepared so that polyamideimide 1 / silica particle concentration (total mass of resin and a silica particle with respect to the mass of a varnish) may be 10 mass%.

After filtering the obtained mixed varnish with the filter of 10 micrometers of the body size, the film thickness of a self-supporting film | membrane is 55 micrometers on the smooth surface of a polyester base material (Toyobo Co., Ltd. brand name "A4100"). It coated using the applicator so that it might become, and it dried for 30 minutes at 50 degreeC, then 15 minutes at 140 degreeC, and peeled the polyester base material, and obtained the self-supporting film. The self-supporting film was fixed to a metal frame and dried at 200 ° C. to obtain an optical film 1 having a film thickness of 50 μm.

Example 2

Except for using methanol dispersion silica sol (MA-ST-G-ML1, primary particle size 27nm) instead of methanol dispersion silica sol "MA-ST-M" In the same manner, an optical film was obtained.

Example 3

(Preparation of polyamideimide)

In a nitrogen gas atmosphere, TFMB 53.05 g (165.66 mmol) and 670.91 g of DMAc were added to a 1 L separable flask equipped with stirring blades, and TFMB was dissolved in DMAc while stirring at room temperature. Next, 22.11 g (49.77 mmol) of 6FDA, 4.88 g (16.59 mmol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA) were added to the flask, followed by 20.21 g of TPC. (99.54 mmol) was added and the mixture was stirred at room temperature for 1 hour. Subsequently, 10.53 g (133.08 mmol) of pyridine and 13.77 g (134.83 mmol) of acetic anhydride were added to the flask, and the mixture was stirred at room temperature for 30 minutes, then heated to 70 ° C. using an oil bath, and further stirred for 3 hours. Got it.

The obtained reaction liquid was cooled to room temperature, poured into a large amount of methanol in filament, and the precipitate which precipitated was taken out, and after immersing in methanol for 6 hours, it wash | cleaned with methanol. Next, the precipitate was dried under reduced pressure at 100 ° C to obtain polyamideimide 2. The weight average molecular weight of the obtained polyamideimide 2 was 190,000.

(Manufacture of optical film)

The optical film was obtained like Example 1 except having used the said polyamideimide 2 as polyamideimide, and using methanol dispersion silica sol "MA-ST-G-ML1" as a GBL dispersion silica sol.

Comparative Example 1

An optical film was obtained in the same manner as in Example 1 except that a water-dispersed silica sol (manufactured by Nissan Chemical Co., Ltd., “ST-O-40, primary particle diameter 23 nm)) was used instead of the methanol dispersed silica sol.

Comparative Example 2

An optical film was obtained in the same manner as in Example 1 except that polyimide (manufactured by Kawamura Sangyo Co., Ltd., “KPI-MX300F”) was used instead of the polyamideimide.

Reference Example 1

An optical film was obtained in the same manner as in Example 1 except that the ratio of polyamide-imide and silica particles was 50:50. The optical film had an elasticity modulus of 7.5 and a bending frequency in the bending resistance test was 140,000 times.

In the optical films obtained in Examples 1 to 3 and Comparative Examples 1 and 2, the type of resin, the silica raw material, the silica content, the silica particle diameter, and the time-of-flight type secondary ion mass spectrometry (TOF-SIMS) were measured. , Table 1 shows the intensity ratio (A / B), total light transmittance, yellowness, haze, and elastic modulus of methoxy ionic strength (A) and silicon ionic strength (B). In Table 1, PAI (1) shows polyamideimide 1, PAI (2) shows polyamideimide 2, PI shows polyamide, and silica content is the mass of an optical film (total of resin and a silica particle). Mass of silica particles).

As shown in Table 1, since the optical film of Comparative Example 1 had a high yellowness, it was confirmed that low yellowness and high elastic modulus were not compatible. Moreover, since the optical film of the comparative example 2 has a low elasticity modulus, it was confirmed that low yellowness and high elastic modulus are incompatible. On the other hand, it was confirmed that the optical films of Examples 1-3 have low yellowness and high elasticity modulus, and are compatible with low yellowness and high elastic modulus.

Claims (11)

An optical film comprising a polyamideimide-based resin and silica particles, wherein when the film cross section is measured by a time-of-flight secondary ion mass spectrometry, an intensity ratio between methoxy ionic strength (A) and silicon ionic strength (B) ( A / B) is at least 0.02,
Content of the said silica particle is 1 mass% or more and 45 mass% or less with respect to the mass of an optical film. The method of claim 1,
The film thickness is 20 micrometers or more. The method of claim 1,
The optical film whose weight average molecular weights of polyamide-imide resin are 100,000-500,000. The method of manufacturing the optical film according to any one of claims 1 to 3, including the step of solvent-substituting a methanol-dispersed silica sol. The method of claim 4, wherein
The method further includes mixing the solvent-substituted silica sol with the polyamideimide-based resin to prepare a varnish. The method of claim 5,
Further comprising applying the varnish to the substrate to form a coating film. The method of claim 6,
And drying the coating film to form an optical film. The flexible image display apparatus provided with the optical film as described in any one of Claims 1-3. The method of claim 8,
A flexible image display device further comprising a polarizing plate. The method of claim 8,
A flexible image display device further comprising a touch sensor. delete