WO2016076243A1 - Resin film, laminated film, optical member, display member, front plate, and method for producing laminated film - Google Patents

Abstract

　Provided is a laminated film comprising: a resin film containing a polyimide polymer; and a functional layer provided on at least one of the principal plane sides of the resin film. Also provided is a resin film containing a polyimide polymer and a silicon material containing silicon atoms, wherein on at least one of the principal planes, the Si/N ratio, which is the atomic ratio of silicon atoms to nitrogen atoms, is at least 8.

Description

Resin film, laminated film, optical member, display member, front plate, and laminated film manufacturing method

The present invention relates to a resin film, a laminated film, an optical member, a display member, a front plate, and a method for producing a laminated film.

Conventionally, glass has been used as a base material for various display members such as solar cells or displays. However, glass has drawbacks such as being easily broken and heavy, and has not always had sufficient material properties when the display is made thinner, lighter and more flexible. Therefore, as a material that can replace glass, an acrylic resin and a laminated film that imparts scratch resistance to the resin have been studied. In addition, a composite material of an organic material and an inorganic material such as a hybrid film containing polyimide and silica has been studied (for example, see Patent Documents 1 and 2).

JP 2008-163309 A US Pat. No. 8,207,256

A laminated film having a known acrylic resin as a base material and having a functional layer provided on the base material is not always sufficient in terms of flexibility to be used as a display member or a front plate of a flexible device.

Therefore, an object of one aspect of the present invention is to provide a laminated film having excellent flexibility.

Also, in order to use the laminated film as a display member or front plate of a flexible device, it is also required to have good visibility when bent. However, even a laminated film having excellent flexibility may cause changes in contrast and hue when bent.

Therefore, another aspect of the present invention aims to improve the visibility during bending of a laminated film having a functional layer.

In order to use a hybrid film containing a polyimide-based polymer and silica as a flexible member, it is generally necessary to form a functional layer having various functions such as an optical adjustment function and an adhesive function on the hybrid film. However, when the functional layer is formed on the hybrid film, the adhesion between the functional layer and the hybrid film may not always be sufficient.

Therefore, still another aspect of the present invention aims to provide a resin film excellent in adhesion to various functional layers and a laminated film using the same.

According to the present invention, an optical member using a laminated film, a display member, and a flexible device front plate are also provided.

The laminated film according to one embodiment of the present invention includes a resin film (resin base material) containing a polyimide polymer and a functional layer provided on at least one main surface side of the resin film.

In the laminated film according to one aspect of the present invention, the silicon material may be silica particles.

When a light irradiation test for irradiating the laminated film with light of 313 nm from the functional layer side for 24 hours with a light source with an output of 40 W provided at a distance of 5 cm from the laminated film according to one aspect is performed. The following conditions:
(I) The laminated film after the light irradiation test has a transmittance of 85% or more for light of 550 nm, and
(Ii) The laminated film before the light irradiation test has a yellowness of 5 or less, and the difference in yellowness before and after the light irradiation test of the laminated film is less than 2.5.
May be satisfied. The resin film after the light irradiation test may have a haze of 1.0% or less.

In the laminated film according to an aspect of the present invention, the functional layer may be a layer having at least one function selected from the group of ultraviolet absorption, surface hardness, adhesiveness, hue adjustment, and refractive index adjustment. .

In the laminated film according to one aspect of the present invention, the functional layer may be a layer having at least one function of ultraviolet absorption and surface hardness.

The resin film according to one embodiment of the present invention contains a polyimide polymer and a silicon material containing silicon atoms. 8 or more may be sufficient as Si / N which is atomic ratio of a silicon atom and a nitrogen atom in the at least one main surface of this resin fill. The silicon material may be silica particles.

The laminated film which concerns on 1 aspect of this invention is equipped with the resin film which concerns on 1 aspect of this invention, and the functional layer provided in the main surface side whose Si / N of this resin film is 8 or more.

In the laminated film according to one embodiment of the present invention, a primer layer may be provided between the resin film and the functional layer. The primer layer may contain a silane coupling agent. The silane coupling agent may have at least one substituent selected from the group consisting of a methacryl group, an acryl group, and an amino group.

The optical member according to one aspect of the present invention includes the laminated film of the present invention. The display member which concerns on 1 aspect of this invention comprises the laminated | multilayer film of this invention. The front plate according to one embodiment of the present invention includes the laminated film of the present invention.

According to the present invention, a laminated film having excellent flexibility can be provided. The laminated film of the present invention can have functions such as transparency, ultraviolet resistance, and surface hardness required when applied to an optical member, a display member, or a front plate of a flexible device. ADVANTAGE OF THE INVENTION According to this invention, the laminated | multilayer film excellent in the visibility at the time of a bending can be provided.

According to the present invention, it is possible to provide a resin film having excellent adhesion to various functional layers, a laminated film using the resin film, and a method for producing the laminated film. The present invention can further provide an optical member, a display member, and a front plate using a laminated film. The resin film obtained in the present invention can have excellent transparency and flexibility.

It is a schematic sectional drawing which shows the resin film of 1st embodiment. It is a schematic sectional drawing which shows the laminated | multilayer film of 2nd embodiment. It is a schematic sectional drawing which shows the laminated film of 3rd embodiment. It is a schematic sectional drawing which shows an example of a display apparatus.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[First embodiment]
FIG. 1 is a schematic cross-sectional view showing the resin film of the present embodiment. The resin film 10 of the present embodiment contains a polyimide-based polymer and has a pair of opposed main surfaces 10a and 10b.

The polyimide polymer contained in the resin film 10 may be polyimide. The polyimide is, for example, a condensation type polyimide obtained by polycondensation using diamines and tetracarboxylic dianhydride as starting materials. As the polyimide polymer, a polymer that is soluble in a solvent used for forming a resin film can be selected.

The diamines are not particularly limited, and aromatic diamines, alicyclic diamines, aliphatic diamines and the like that are usually used for the synthesis of polyimide can be used. Diamines may be used alone or in combination of two or more.

As tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, acyclic aliphatic tetracarboxylic dianhydride and the like can be used, and are particularly limited. There is nothing. A tetracarboxylic dianhydride may be used independently and may use 2 or more types together. Instead of tetracarboxylic dianhydride, a tetracarboxylic acid compound selected from tetracarboxylic acid compound analogs such as an acid chloride compound may be used as a starting material.

At least one of diamines and tetracarboxylic acid compounds (tetracarboxylic dianhydrides) is a fluorine-based substituent, a hydroxyl group, a sulfone group, a carbonyl group, a heterocyclic ring, or a long-chain alkyl group having 1 to 10 carbon atoms. It may have one or more at least one functional group selected from the group consisting of Among these, from the viewpoint of transparency, diamines and tetracarboxylic acid compounds (tetracarboxylic dianhydrides) may have a fluorine-based substituent introduced as a functional group. The fluorine-based substituent may be a group containing a fluorine atom, and specific examples thereof are a fluorine group (fluorine atom, -F) and a trifluoromethyl group.

From the viewpoint of solubility in a solvent, transparency when the resin film 10 is formed, and flexibility, an alicyclic tetracarboxylic acid compound (such as an alicyclic tetracarboxylic dianhydride) or aromatic is used as the tetracarboxylic acid compound. Tetracarboxylic acid compounds (such as aromatic tetracarboxylic dianhydrides) can be used. From the viewpoint of transparency of the resin film and suppression of coloring, an alicyclic tetracarboxylic acid compound or an aromatic tetracarboxylic acid compound having a fluorine-based substituent can be used as the tetracarboxylic dianhydride.

As the diamines, aromatic diamines, alicyclic diamines, and aliphatic diamines may be used alone or in combination of two or more. From the viewpoint of solubility in a solvent, transparency when the resin film 10 is formed, and flexibility, an alicyclic diamine or an aromatic diamine can be used as the diamine. From the viewpoint of transparency of the resin film and suppression of coloring, alicyclic diamine or aromatic diamine having a fluorine-based substituent can be used as the diamine.

If a polyimide polymer is used, it has particularly excellent flexibility, high light transmittance (for example, 85% or more or 88% or more for 550 nm light), and low yellowness (YI value, for example, 5 or less or 3 or less), and a low haze (for example, 1.5% or less or 1.0% or less) resin film is easily obtained.

The polyimide may have a repeating structural unit represented by the following (PI) formula. Here, G is a tetravalent organic group, and A is a divalent organic group.

Examples of G include a tetravalent organic group selected from the group consisting of an acyclic aliphatic group, a cyclic aliphatic group, and an aromatic group. G may be a cyclic aliphatic group or an aromatic group. Examples of the aromatic group include a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group having two or more aromatic rings, which are connected to each other directly or by a bonding group. Family groups and the like. From the viewpoint of transparency of the resin film and suppression of coloring, G may be a cyclic aliphatic group, a cyclic aliphatic group having a fluorine-based substituent, a monocyclic aromatic group, a condensed group. It may be a polycyclic aromatic group or a non-fused polycyclic aromatic group. More specifically, a saturated or unsaturated cycloalkyl group, a saturated or unsaturated heterocycloalkyl group, an aryl group, a heteroaryl group, an arylalkyl group, an alkylaryl group, a heteroalkylaryl group, and among these Examples thereof include groups having any two groups (which may be the same), which are connected to each other directly or by a bonding group. Examples of the bonding group include —O—, an alkylene group having 1 to 10 carbon atoms, —SO ₂ —, —CO— or —CO—NR— (where R represents a methyl group, an ethyl group, a propyl group, etc. 3 represents an alkyl group or a hydrogen atom). The carbon number of G is usually 2 to 32, and may be 2 to 27, 5 to 10, 6 to 8, or 3 to 8. When G is a cycloaliphatic group or an aromatic group, some of the carbon atoms may be replaced with heteroatoms. Examples of G are saturated or unsaturated cycloalkyl groups, saturated or unsaturated heterocycloalkyl groups, which can have 3 to 8 carbon atoms. Examples of heteroatoms include O, N and S.

Specifically, G is a group represented by the following formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), or formula (26). be able to. * In the formula indicates a bond. Z is a single bond, —O—, —CH ₂ —, —C (CH ₃ ) ₂ —, —Ar—O—Ar—, —Ar—CH ₂ —Ar—, —Ar—C (CH ₃ ) ₂ —Ar— or —Ar—SO ₂ —Ar— is represented. Ar represents an aryl group having 6 to 20 carbon atoms, and an example thereof is a phenylene group (benzene ring). At least one of the hydrogen atoms of these groups may be substituted with a fluorine-based substituent.

A includes a divalent organic group selected from the group consisting of an acyclic aliphatic group, a cyclic aliphatic group, and an aromatic group. The divalent organic group represented by A may be a cyclic aliphatic group or an aromatic group. Examples of the aromatic group include a monocyclic aromatic group, a condensed polycyclic aromatic group, and a non-condensed polycyclic aromatic group having two or more aromatic rings and connected to each other directly or by a bonding group. Groups. From the viewpoints of transparency of the resin film and suppression of coloring, a fluorine-based substituent may be introduced into at least a part of A.

More specifically, A is a saturated or unsaturated cycloalkyl group, a saturated or unsaturated heterocycloalkyl group, an aryl group, a heteroaryl group, an arylalkyl group, an alkylaryl group, a heteroalkylaryl group, and these And a group having any two groups (which may be the same) in which they are connected to each other directly or by a bonding group. Heteroatoms include O, N and S. Examples of the linking group include —O—, an alkylene group having 1 to 10 carbon atoms, —SO ₂ —, —CO—, and —CO—NR— (where R represents a methyl group, an ethyl group, a propyl group, etc. 3 represents an alkyl group or a hydrogen atom).
The carbon number of the divalent organic group represented by A is usually 2 to 40, and may be 5 to 32, 12 to 28, or 24 to 27.

Specifically, A can be a group represented by the following formula (30), formula (31), formula (32), formula (33), or formula (34). * In the formula indicates a bond. Z ¹ , Z ² and Z ³ are each independently a single bond, —O—, —CH ₂ —, —C (CH ₃ ) ₂ —, —SO ₂ —, —CO— or —CO—NR—. (R represents an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, or a propyl group, or a hydrogen atom). In the following groups, Z ¹ and Z ² , and Z ² and Z ³ are each preferably in the meta position or the para position with respect to each ring. Further, it is preferable that Z ¹ and the single bond at the end, Z ² and the single bond at the end, and Z ³ and the single bond at the end are in the meta position or the para position. In one example, Z ¹ and Z ³ are —O— and Z ² is —CH ₂ —, —C (CH ₃ ) ₂ — or —SO ₂ —. At least one of the hydrogen atoms of these groups may be substituted with a fluorine-based substituent.

In at least one of A and G, at least one hydrogen atom is selected from the group consisting of fluorine-containing substituents containing fluorine atoms such as fluorine and trifluoromethyl groups, hydroxyl groups, sulfone groups, alkyl groups having 1 to 10 carbon atoms, and the like. It may be substituted with at least one functional group selected. When A and G are each a cyclic aliphatic group or an aromatic group, at least one of the above A or G may have a fluorine-based substituent, and both A and G have a fluorine-based substituent. You may have.

The polyimide polymer may be a polymer including at least one repeating structural unit represented by the formula (PI), the formula (a), the formula (a ′), or the formula (b). G ² in the formula (a) represents a trivalent organic group, and A ² represents a divalent organic group. G ³ in the formula (a ′) represents a tetravalent organic group, and A ³ represents a divalent organic group. G ⁴ and A ⁴ in the formula (b) each represent a divalent organic group.

G ² in formula (a) can be selected from the same groups as G in formula (PI) except that it is a trivalent group. For example, G ² may be a group in which any one of the four bonds in the groups represented by the formulas (20) to (26) exemplified as specific examples of G is replaced with a hydrogen atom. . A ² in formula (a) can be selected from the same groups as A in formula (PI).

G ³ in formula (a ′) can be selected from the same groups as G in formula (PI). A ³ in formula (a ′) can be selected from the same groups as A in formula (PI).

G ⁴ in formula (b) can be selected from the same groups as G in formula (PI) except that it is a divalent group. For example, G ⁴ may be a group in which any two of the four bonds in the groups represented by formulas (20) to (26) exemplified as specific examples of G are replaced with hydrogen atoms. . A ⁴ in formula (b) can be selected from the same groups as A in formula (PI).

A polyimide polymer, which is a polymer containing at least one repeating structural unit represented by formula (PI), formula (a), formula (a ′) or formula (b), is a diamine and a tetracarboxylic acid compound. Alternatively, it may be a condensed polymer obtained by polycondensation with at least one of tricarboxylic acid compounds (including tricarboxylic acid compound analogs such as acid chloride compounds and tricarboxylic acid anhydrides). In addition to these, a dicarboxylic acid compound (including analogs such as an acid chloride compound) may be used as a starting material. The repeating structural unit represented by the formula (a ′) is generally derived from a diamine and a tetracarboxylic acid compound. The repeating structural unit represented by the formula (a) is usually derived from diamines and tricarboxylic acid compounds. The repeating structural unit represented by the formula (b) is usually derived from diamines and dicarboxylic acid compounds. Specific examples of the diamines and tetracarboxylic acid compounds are as described above.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acid, alicyclic tricarboxylic acid, acyclic aliphatic tricarboxylic acid, and related acid chloride compounds, acid anhydrides and the like. The tricarboxylic acid compound may be an aromatic tricarboxylic acid, an alicyclic tricarboxylic acid, an acyclic aliphatic tricarboxylic acid, or an acid chloride compound thereof. Two or more tricarboxylic acid compounds may be used in combination.

From the viewpoint of solubility in a solvent, transparency when the resin film 10 is formed, and flexibility, the tricarboxylic acid compound can be selected from alicyclic tricarboxylic acid compounds and aromatic tricarboxylic acid compounds. From the viewpoint of transparency of the resin film and suppression of coloring, the tricarboxylic acid compound may include an alicyclic tricarboxylic acid compound having a fluorine-based substituent and an aromatic tricarboxylic acid compound having a fluorine-based substituent.

Examples of the dicarboxylic acid compound include aromatic dicarboxylic acid, alicyclic dicarboxylic acid, acyclic aliphatic dicarboxylic acid, and related acid chloride compounds, acid anhydrides and the like. The dicarboxylic acid compound may be an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, an acyclic aliphatic dicarboxylic acid, or an acid chloride compound thereof. Two or more dicarboxylic acid compounds may be used in combination.

From the viewpoint of solubility in a solvent, transparency when the resin film 10 is formed, and flexibility, the dicarboxylic acid compound can be selected from an alicyclic dicarboxylic acid compound and an aromatic dicarboxylic acid compound. From the viewpoint of transparency of the resin film and suppression of coloring, the dicarboxylic acid compound can be selected from an alicyclic dicarboxylic acid compound having a fluorine-based substituent and an aromatic dicarboxylic acid compound having a fluorine-based substituent.

The polyimide polymer may be a copolymer containing a plurality of different types of repeating units. The weight average molecular weight of the polyimide polymer is usually 10,000 to 500,000. The weight average molecular weight of the polyimide polymer may be 50,000 to 500,000, 100,000 to 500,000, or 70,000 to 400,000. The weight average molecular weight is a standard polystyrene equivalent molecular weight measured by GPC. When the weight average molecular weight of the polyimide-based polymer is large, there is a tendency that high flexibility is easily obtained. When the weight-average molecular weight of the polyimide-based polymer is too large, the viscosity of the varnish increases and the workability tends to decrease. is there.

The polyimide-based polymer may contain a halogen atom such as a fluorine atom that can be introduced by the above-described fluorine-based substituent. When the polyimide polymer contains a halogen atom, the elastic modulus of the resin film can be improved and the yellowness can be reduced. Thereby, it can suppress that a crack, wrinkles, etc. generate | occur | produce in a resin film, and can improve the transparency of a resin film. For example, the fluorine atom is a polyimide (polyimide polymer) molecule by using a compound having a fluorine substituent such as a fluorine group or a trifluoromethyl group as at least one of diamines or tetracarboxylic dianhydrides. Can be introduced. The content of halogen atoms (or fluorine atoms) in the polyimide may be 1% by mass to 40% by mass, or 1% by mass to 30% by mass based on the mass of the polyimide polymer.

The resin film 10 may further contain an inorganic material such as inorganic particles. The inorganic material may be a silicon material containing silicon atoms. When the resin film 10 contains an inorganic material such as a silicon material, a particularly excellent effect can be obtained in terms of flexibility.

Examples of the silicon material containing silicon atoms include silica compounds and silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate (TEOS). The silicon material may be silica particles from the viewpoint of the transparency and flexibility of the resin film 10.

The average primary particle diameter of the silica particles may be 10 nm to 100 nm, or 20 nm to 80 nm. When the average primary particle diameter of the silica particles is 100 nm or less, the transparency tends to be improved. When the average primary particle diameter of the silica particles is 10 nm or more, the strength of the resin film tends to be improved, and the cohesive force of the silica particles tends to be weakened, so that the handling tends to be easy.

The (average) primary particle diameter of the silica particles in the resin film can be determined by observation with a transmission electron microscope (TEM). The particle distribution of the silica particles before forming the resin film can be determined by a commercially available laser diffraction particle size distribution meter.

In the resin film 10, the compounding ratio of the polyimide and the inorganic material (silicon material) may be 1: 9 to 10: 0 or 1: 9 to 9: 1 by mass ratio, and may be 3: 7 to 10: 0. Alternatively, it may be 3: 7 to 8: 2. This blending ratio may be 3: 7 to 8: 2, or 3: 7 to 7: 3. The ratio of the inorganic material to the total mass of the polyimide and the inorganic material is usually 20% by mass or more, and may be 30% by mass or more. This ratio is usually 90% by mass or less and may be 70% by mass or less. There exists a tendency for the transparency and mechanical strength of a resin film to improve that the compounding ratio of a polyimide and an inorganic material (silicon material) exists in said range.

Resin film 10 may further contain components other than polyimide and inorganic material (silicon material) as long as transparency and flexibility are not significantly impaired. Examples of components other than polyimide and inorganic materials (silicon materials) include antioxidants, mold release agents, stabilizers, bluing agents, flame retardants, lubricants, and leveling agents. The total ratio of the polyimide and the inorganic material may be greater than 0% and not greater than 20% by mass, and may be greater than 0% and not greater than 10% by mass with respect to the mass of the resin film 10.

When the resin film 10 contains a polyimide and a silicon material, Si / N that is the atomic ratio of silicon atoms to nitrogen atoms in at least one main surface 10a may be 8 or more. This atomic ratio Si / N is determined by evaluating the composition of the main surface 10a by X-ray photoelectron spectroscopy (XPS) and calculating the amount of silicon atoms and the amount of nitrogen atoms present. This is a calculated value.

When Si / N in the main surface 10a of the resin film 10 is 8 or more, sufficient adhesion with the functional layer 20 described later is obtained. From the viewpoint of adhesion, Si / N may be 9 or more, or 10 or more. , Si / N is usually 50 or less and may be 40 or less.

The thickness of the resin film 10 is appropriately adjusted according to the flexible device to which the laminated film 30 is applied, but may be 10 μm to 500 μm, 15 μm to 200 μm, or 20 μm to 100 μm. The resin film 10 having such a configuration can have particularly excellent flexibility.

Next, an example of the manufacturing method of the resin film 10 of this embodiment is demonstrated.
Solvent-soluble polyimide polymerized using a known polyimide synthesis method is dissolved in a solvent to prepare a polyimide varnish. The solvent may be any solvent that dissolves polyimide. For example, N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), or those (A mixed solvent).

When producing a resin film containing an inorganic material (silicon material), the inorganic material was then added to the polyimide polymer varnish and stirred and mixed by a known stirring method to uniformly disperse the silicon material. Prepare a dispersion.

The compounding ratio of the polyimide and the inorganic material in the polyimide-based polymer varnish or dispersion may be 1: 9 to 9: 1 or 3: 7 to 8: 2 by mass ratio.

The polyimide polymer varnish or dispersion may further contain an additive. Additives are selected from, for example, antioxidants, mold release agents, stabilizers, bluing agents, flame retardants, lubricants, and leveling agents. The polyimide-based polymer varnish or dispersion may contain a compound such as alkoxysilane having one or more metal alkoxide groups that contributes to bond formation between inorganic particles (silica particles and the like). By using a dispersion containing such a compound, the blending ratio of the inorganic particles can be increased while maintaining optical properties such as transparency of the resin film. An example of such a compound is an alkoxysilane having an amino group.

Next, the above dispersion is applied to the substrate by, for example, a known roll-to-roll or batch method to form a coating film. The coating is dried to form a film. Then, the resin film 10 is obtained by peeling a film from a base material. The substrate may be, for example, a polyethylene terephthalate (PET) substrate, a SUS belt, or a glass substrate.

The coating film may be heated for drying and / or baking the coating film. The coating film can be appropriately heated at a temperature of 50 ° C. to 350 ° C. under an inert atmosphere or under reduced pressure. The solvent can be evaporated by heating the coating film. The resin film may be formed by a method including drying the coating film at 50 to 150 ° C. and baking the dried coating film at 180 to 350 ° C.

Next, surface treatment may be performed on at least one main surface of the resin film. The surface treatment may be UV ozone treatment. By UV ozone treatment, Si / N can be easily increased to 8 or more. However, the method of setting Si / N to 8 or more is not limited to UV ozone treatment. The main surface 10a and / or 10b of the resin film 10 may be subjected to a surface treatment such as a plasma treatment or a corona discharge treatment in order to improve adhesion with a functional layer described later.

UV ozone treatment can be performed using a known ultraviolet light source including a wavelength of 200 nm or less. An example of an ultraviolet light source is a low-pressure mercury lamp. As the ultraviolet light source, various commercially available devices equipped with an ultraviolet light source may be used. Examples of the commercially available apparatus include an ultraviolet (UV) ozone cleaning apparatus UV-208 manufactured by Technovision.

The resin film 10 of the present embodiment thus obtained is excellent in flexibility. Moreover, when at least one principal surface 10a has Si / N, which is the atomic ratio of silicon atoms and nitrogen atoms, of 8 or more, excellent adhesion to the functional layer 20 described later can be obtained.

[Second Embodiment]
Hereinafter, with reference to FIG. 2, the laminated film which concerns on 2nd embodiment is demonstrated.
FIG. 2 is a schematic cross-sectional view showing the laminated film of the present embodiment. In FIG. 2, the same components as those of the resin film of the first embodiment shown in FIG.
The laminated film 30 of the present embodiment is roughly configured from a resin film 10 and a functional layer 20 laminated on one main surface 10 a of the resin film 10.

The functional layer 20 may be a layer for further imparting a function (performance) to the laminated film 30 when the laminated film 30 is used as an optical member, a display member, or a front plate of a flexible device. The functional layer 20 may be a layer having at least one function selected from the group consisting of ultraviolet absorption, surface hardness, adhesiveness, hue adjustment, and refractive index adjustment.

As the functional layer 20, the layer having an ultraviolet absorption function (ultraviolet absorption layer) is, for example, a main material selected from an ultraviolet curable transparent resin, an electron beam curable transparent resin, and a thermosetting transparent resin. And an ultraviolet absorber dispersed in the main material. By providing an ultraviolet absorbing layer as the functional layer 20, it is possible to easily suppress a change in yellowness due to light irradiation.

The ultraviolet curable, electron beam curable, or thermosetting transparent resin as the main material of the ultraviolet absorbing layer is not particularly limited, and may be, for example, poly (meth) acrylate.
The ultraviolet absorber may contain, for example, at least one compound selected from the group consisting of benzophenone compounds, salicylate compounds, benzotriazole compounds, and triazine compounds.
In the present specification, the “system compound” refers to a derivative of the compound to which the “system compound” is attached. For example, a “benzophenone compound” refers to a compound having benzophenone as a host skeleton and a substituent bonded to benzophenone. The same applies to other “system compounds”.

The ultraviolet absorbing layer may be a layer that absorbs 95% or more of light having a wavelength of 400 nm or less (for example, light having a wavelength of 313 nm). In other words, the ultraviolet absorbing layer may be a layer having a transmittance of light having a wavelength of 400 nm or less (for example, light having a wavelength of 313 nm) of less than 5%. The ultraviolet absorbing layer can contain an ultraviolet absorber having a concentration such that such transmittance can be obtained. From the viewpoint of suppressing an increase in yellowness of the laminated film due to light irradiation, the proportion of the ultraviolet absorber in the ultraviolet absorbing layer (functional layer 20) is usually 1% by mass or more based on the mass of the ultraviolet absorbing layer. It may be greater than or equal to mass%. This ratio is usually 10% by mass or less and may be 8% by mass or less.

The layer (hard coat layer) having the function of surface hardness (function of expressing high hardness on the surface) as the functional layer 20 is, for example, a laminated film having a surface having a pencil hardness higher than the pencil hardness of the surface of the resin film. It is a layer to give to. The pencil hardness of the surface of the hard coat layer may be 2H or more, for example. The hard coat layer is not particularly limited, but includes an ultraviolet curable resin, an electron beam curable resin, or a thermosetting resin typified by poly (meth) acrylates. The hard coat layer may contain a photopolymerization initiator and an organic solvent. Poly (meth) acrylates are formed from, for example, one or more (meth) acrylates selected from polyurethane (meth) acrylate, epoxy (meth) acrylate, and other polyfunctional poly (meth) acrylates. It is a poly (meth) acrylate containing a monomer unit derived therefrom. The hard coat layer may contain inorganic oxides such as silica, alumina and polyorganosiloxane in addition to the above components.

The layer having the adhesive function (adhesive layer) as the functional layer 20 has a function of bonding the laminated film 30 to another member. As the material for forming the adhesive layer, a conventionally known material can be used. For example, a thermosetting resin composition or a photocurable resin composition can be used.

The adhesive layer may be composed of a resin composition containing a component having a polymerizable functional group. In this case, strong adhesion can be realized by further polymerizing the resin composition constituting the adhesive layer after the laminated film 30 is adhered to another member. The adhesive strength between the resin film 10 and the adhesive layer may be 0.1 N / cm or more, or 0.5 N / cm or more.

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

The pressure-sensitive adhesive layer may be a layer called a pressure-sensitive adhesive (Pressure Sensitive Adhesive, PSA) that is stuck to an object by pressing. The pressure-sensitive adhesive may be a pressure-sensitive adhesive that is “a substance that is sticky at normal temperature and adheres to an adherend with light pressure” (JIS K6800). And an adhesive that can maintain stability until the coating is broken by appropriate means (pressure, heat, etc.) (JIS K6800).

The layer having a function of adjusting the hue (hue adjusting layer) as the functional layer 20 is a layer capable of adjusting the laminated film 30 to a target hue. A hue adjustment layer is a layer containing resin and a coloring agent, for example. Examples of the colorant include inorganic pigments such as titanium oxide, zinc oxide, dial, titanium oxide-based fired pigment, ultramarine, cobalt aluminate, and carbon black; azo-based compounds, quinacridone-based compounds, anthraquinone-based compounds, Organic pigments such as perylene compounds, isoindolinone compounds, phthalocyanine compounds, quinophthalone compounds, selenium compounds, and diketopyrrolopyrrole compounds; body pigments such as barium sulfate and calcium carbonate; basic dyes, acid dyes and There may be mentioned dyes such as mordant dyes.

The layer having a function of adjusting the refractive index (refractive index adjusting layer) as the functional layer 20 is a layer that has a refractive index different from that of the resin film 10 and can impart a predetermined refractive index to the laminated film. . The refractive index adjustment layer may be, for example, an appropriately selected resin, and optionally a resin layer further containing a pigment, or may be a metal thin film.

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

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

The functional layer 20 appropriately has the above function according to the use of the laminated film 30. The functional layer 20 may be a single layer or a plurality of layers. Each layer may have one function or two or more functions.

The functional layer 20 may have a function of surface hardness and ultraviolet absorption. The functional layer 20 in this case is “a single layer having a function of surface hardness and UV absorption”, “a multilayer including a layer having a surface hardness and a layer having UV absorption”, or “a function of surface hardness and UV absorption” And a multilayer including a layer having a surface hardness ”.

The thickness of the functional layer 20 is appropriately adjusted according to the flexible device to which the laminated film 30 is applied, and may be, for example, 1 μm to 100 μm, or 2 μm to 80 μm. The functional layer 20 is typically thinner than the resin film 10.

The laminated film 30 can be obtained by forming the functional layer 20 on the main surface 10 a of the resin film 10. The functional layer 20 can be formed by a known roll-to-roll or batch method.

The ultraviolet absorbing layer as the functional layer 20 is formed by, for example, applying a dispersion liquid containing an ultraviolet absorbent and a main material such as a resin in which the ultraviolet absorbent is dispersed to the main surface 10a of the resin film 10. It can be formed by a method of forming and drying and curing the coating film.

The hard coat layer as the functional layer 20 is, for example, a method in which a solution containing a resin for forming the hard coat layer is applied to the main surface 10a of the resin film 10 to form a coating film, and the coating film is dried and cured. Can be formed.

The pressure-sensitive adhesive layer as the functional layer 20 is formed by, for example, applying a solution containing a pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer to the main surface 10a of the resin film 10 to form a coating film, and drying and curing the coating film. Can be formed.

The hue adjustment layer as the functional layer 20 is, for example, applied to the main surface 10a of the resin film 10 with a dispersion liquid containing a pigment or the like that forms the hue adjustment layer and a main material such as a resin in which the pigment or the like is dispersed. The coating film can be formed by a method of forming a coating film and drying and curing the coating film.

The refractive index adjusting layer as the functional layer 20 is a dispersion containing, for example, inorganic particles that form the refractive index adjusting layer on the main surface 10a of the resin film 10 and a main material such as a resin in which the inorganic particles are dispersed. It can be formed by applying a liquid to form a coating film, and drying and curing the coating film.

As the functional layer 20, a single layer having a function of surface hardness and ultraviolet absorption includes an ultraviolet absorber, a main material such as a resin in which the ultraviolet absorber is dispersed, and a hard coat layer on the main surface 10a of the resin film 10. It can form by the method of apply | coating the dispersion liquid containing resin which forms, forming a coating film, and drying and hardening the coating film. The resin of the main material and the resin forming the hard coat layer may be the same.

Applying a dispersion liquid containing a UV absorber and a main material such as a resin in which the UV absorber is dispersed to the main surface 10a of the resin film 10 to form a coating film, and drying and curing the coating film By forming a UV-absorbing layer, and then applying a solution containing a resin that forms the hard-coat layer to the UV-absorbing layer to form a coating film, and then drying and curing the coating film, A layer may be formed. By this method, a multilayer functional layer including a layer having surface hardness and a layer having ultraviolet absorption is formed.

A coating film is formed on the main surface 10a of the resin film 10 by applying a dispersion containing an ultraviolet absorbent, a main material such as a resin in which the ultraviolet absorbent is dispersed, and a resin that forms a hard coat layer, The coating film is dried and cured to form a single layer having a function of surface hardness and ultraviolet absorption, and further, a solution containing a resin for forming a hard coat layer is applied onto the single layer to form a coating film. The hard coat layer may be formed by forming and drying and curing the coating film. By this method, a multilayer functional layer including a layer having a function of surface hardness and ultraviolet absorption and a layer having a surface hardness is formed.

The thus obtained laminated film 30 of this embodiment is excellent in flexibility. The laminated film 30 can have functionality such as transparency, ultraviolet resistance, and surface hardness required when applied to an optical member, a display member, or a front plate of a flexible device. When Si / N in the main surface 10a of the resin film 10 is 8 or more, the adhesion between the resin film 10 and the functional layer 20 is also excellent.

When a light irradiation test for irradiating the laminated film 30 with light of 313 nm from the functional layer 20 side for 24 hours by a light source with an output of 40 W provided at a distance of 5 cm from the laminated film 30, the laminated film 30 is as follows. conditions:
(I) The laminated film after the light irradiation test has a transmittance of 85% or more with respect to light of 550 nm, and a haze of 1.0% or less, and
(Ii) The laminated film before the light irradiation test has a yellowness (YI value) of 5 or less, and the difference in yellowness before and after the light irradiation test of the laminated film is less than 2.5.
May be satisfied. A laminated film satisfying these conditions (i) and (ii) is unlikely to cause a change in contrast or hue when bent, and can maintain good visibility.

For example, a layer having an ultraviolet absorption function is provided as the functional layer 20, and the resin film 10 and the functional layer 20 have a transmittance of 85% or more with respect to light of 550 nm and a haze of 1.0% or less. If it is used, a laminated film satisfying the conditions (i) and (ii) can be easily obtained.

90% or more may be sufficient as the transmittance | permeability with respect to 550 nm light of the laminated | multilayer film after a light irradiation test, and it may be 100% or less or 95% or less. The haze of the laminated film after the light irradiation test may be 0.9 or less, or 0.1 or more. The laminated film before the light irradiation test may have a transmittance of 85% or more with respect to light of 550 nm and a haze value of 1.0 or less. Details of the transmittance and haze measurement method will be described in Examples described later.

The yellowness of the laminated film before the light irradiation test may be 4 or less, 3 or less, or 0.5 or more. When the yellowness before the light irradiation test is YI ₀ and the yellowness after the light irradiation is YI ₁ , the difference in yellowness ΔYI before and after the light irradiation test of the laminated film is expressed by the formula: ΔYI = YI ₁ −YI ₀ Calculated by ΔYI is preferably 2.2 or less, may be 2.0 or less, and may be 0.1 or more. Details of the yellowness measurement method will be described in the examples described later.

In the present embodiment, the configuration in which the functional layer 20 is laminated on one main surface 10a of the resin film 10 is illustrated, but the present invention is not limited to this. For example, functional layers may be laminated on both surfaces of the resin film.

The laminated film 30 of this embodiment is used as, for example, an optical member, a display member, or a front plate of a flexible device.

[Third embodiment]
Hereinafter, with reference to FIG. 3, the laminated film which concerns on 3rd embodiment is demonstrated.
FIG. 3 is a schematic cross-sectional view showing the laminated film of the present embodiment. 3, the same code | symbol is attached | subjected to the component which is the same as or respond | corresponds to the laminated film of 2nd embodiment shown in FIG. 2, and the description is abbreviate | omitted. The laminated film 30 of this embodiment includes a resin film 10, a functional layer 20 provided on one main surface 10 a side of the resin film 10, and a primer layer 25 provided between the resin film 10 and the functional layer 20. It is roughly composed of The primer layer 25 is laminated on one main surface 10 a of the resin film 10. The functional layer 20 is laminated on a main surface (hereinafter sometimes referred to as “one main surface”) 25 a opposite to the main surface in contact with the resin film 10 of the primer layer 25.

The primer layer 25 is a layer formed from a primer agent, and preferably contains a material that can enhance adhesion between the resin film 10 and the functional layer 20. The compound contained in the primer layer 25 may be chemically bonded to the polyimide polymer or silicon material contained in the resin film 10 at the interface.

Examples of the primer agent include a primer agent of an epoxy compound of an ultraviolet curing type, a thermosetting type, or a two-component curing type. The primer agent may be a polyamic acid. These are suitable for enhancing the adhesion between the resin film 10 and the functional layer 20.

The primer agent may contain a silane coupling agent. The silane coupling agent may be chemically bonded to the silicon material contained in the resin film 10 by a condensation reaction. The silane coupling agent is particularly useful when the compounding ratio of the silicon material contained in the resin film 10 is high.

The silane coupling agent is a compound having an alkoxysilyl group having a silicon atom and 1 to 3 alkoxy groups covalently bonded to the silicon atom. The silane coupling agent may be a compound including a structure in which two or more alkoxy groups are covalently bonded to a silicon atom, or a compound including a structure in which three alkoxy groups are covalently bonded to a silicon atom. Examples of the alkoxy group include a methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, and a t-butoxy group. Among these, the methoxy group and the ethoxy group can increase the reactivity with the silicon material.

The silane coupling agent can have a substituent having high affinity with the resin film 10 and the functional layer 20. From the viewpoint of affinity with the polyimide polymer contained in the resin film 10, the substituent of the silane coupling agent may be an epoxy group, an amino group, a ureido group, or an isocyanate group. When the functional layer 20 contains (meth) acrylates, if the silane coupling agent used for the primer layer 25 has an epoxy group, a methacryl group, an acrylic group, an amino group, or a styryl group, the affinity tends to increase. There is. Among these, the silane coupling agent having a substituent selected from a methacryl group, an acryl group, and an amino group tends to be excellent in affinity with the resin film 10 and the functional layer 20.

The thickness of the primer layer 25 is appropriately adjusted according to the functional layer 20, but may be 0.01 nm to 20 μm. When an epoxy compound primer is used, the primer layer 25 may have a thickness of 0.01 μm to 20 μm, or 0.1 μm to 10 μm. When a silane coupling agent is used, the primer layer 25 may have a thickness of 0.1 nm to 1 μm, or 0.5 nm to 0.1 μm.

Next, the manufacturing method of the laminated film 30 of FIG. 3 of this embodiment is demonstrated.
First, the resin film 10 is produced similarly to 1st embodiment. Subsequently, the solution which melt | dissolved the primer agent is apply | coated to one main surface 10a of the resin film 10 by a well-known roll-to-roll or batch system, and a 1st coating film is formed. The first coating film may be slightly cured as necessary.

Next, in the same manner as in the first embodiment, the material for the functional layer 20 is applied on the first coating film to form a second coating film. By curing the first coating film and the second coating film simultaneously or individually, the primer layer 25 and the functional layer 20 are formed, and the laminated film 30 is obtained.

The thus obtained laminated film 30 of this embodiment is excellent in flexibility. Since the primer layer 25 is provided between the resin film 10 and the functional layer 20, the adhesiveness between the resin film 10 and the functional layer 20 is high. The laminated film 30 can have functionality such as transparency, ultraviolet resistance, and surface hardness required when applied to an optical member, a display member, and a front plate of a flexible device.

In this embodiment, although the functional layer 20 was provided in the one main surface 10a side of the resin film 10 and the primer layer 25 was provided between the resin film 10 and the functional layer 20, this invention was illustrated. It is not limited to this. A functional layer may be laminated on both sides of the resin film via a primer layer.

[Fourth embodiment]
Hereinafter, the display device according to the fourth embodiment will be described with reference to FIG.
FIG. 4 is a schematic cross-sectional view showing an example of a display device that is an application example of the laminated film of the present embodiment. The display device 100 of this embodiment includes an organic EL device 50, a touch sensor 70, and a front plate 90. These are usually housed in a housing. The organic EL device 50 and the touch sensor 70 and the touch sensor 70 and the front plate 90 are bonded with, for example, an optical adhesive (Optical Clear Adhesive, OCA).

The organic EL device 50 includes an organic EL element 51, a first substrate 55, a second substrate 56, and a sealing material 59.

The organic EL element 51 has a pair of electrodes (first electrode 52 and second electrode 53) and a light emitting layer 54. The light emitting layer 54 is disposed between the first electrode 52 and the second electrode 53.

The first electrode 52 is made of a light-transmitting conductive material. The second electrode 53 may also have optical transparency. As the first electrode 52 and the second electrode 53, a known material can be employed.

The light emitting layer 54 can be formed of a known light emitting material constituting the organic EL element. The light emitting material may be either a low molecular compound or a high molecular compound.

When electric power is supplied between the first electrode 52 and the second electrode 53, carriers (electrons and holes) are supplied to the light emitting layer 54, and light is generated in the light emitting layer 54. The light generated in the light emitting layer 54 is emitted to the outside of the organic EL device 50 through the first electrode 52 and the first substrate 55.

The first substrate 55 is made of a light transmissive material. The second substrate 56 may be light transmissive. The 1st board | substrate 55 and the 2nd board | substrate 56 are bonded together by the sealing material 59 arrange | positioned so that the circumference | surroundings of an organic EL element may be enclosed. The first substrate 55, the second substrate 56, and the sealing material 59 form a sealing structure that seals the organic EL element inside. The first substrate 55 and / or the second substrate 56 is often a gas barrier material.

As a material for forming one or both of the first substrate 55 and the second substrate 56, an inorganic material such as glass or a known transparent resin such as an acrylic resin can be used. As these members, the laminated film according to this embodiment described above can also be employed.

The first substrate 55 and the second substrate 56 that can employ the laminated film according to the present embodiment correspond to the display member or the gas barrier material in the present embodiment. The organic EL device 50 having such a first substrate 55 and a second substrate 56 employs the laminated film according to this embodiment, and thus has excellent flexibility.

The touch sensor 70 includes a substrate 71 (touch sensor base material) and an element layer 72 having a detection element formed on the substrate 71.

The substrate 71 is made of a light transmissive material. As the substrate 71, an inorganic material such as glass or a known transparent resin such as an acrylic resin can be used. As the substrate 71, the above-described laminated film according to this embodiment can also be employed.

In the element layer 72, a known detection element composed of a semiconductor element, a wiring, a resistor, and the like is formed. As a configuration of the detection element, a configuration that realizes a known detection method such as a matrix switch, a resistance film method, or a capacitance method can be adopted.

The substrate 71 that can employ the laminated film according to the present embodiment corresponds to the optical member in the present embodiment. Since the touch sensor 70 having such a substrate 71 employs the laminated film according to this embodiment, the touch sensor 70 has excellent flexibility.

The front plate 90 is made of a light transmissive material. The front plate 90 is located on the outermost layer on the display screen side of the display device and functions as a protective member that protects the display device. The front plate may be referred to as a window film. As the front plate 90, an inorganic material such as glass or a known transparent resin such as an acrylic resin can be used. As the front plate 90, the laminated film according to the present embodiment described above can also be employed. When a laminated film is employed as the front plate 90, the laminated film is usually arranged in such a direction that the functional layer is located outside the display device.

The front plate 90 that can employ the laminated film according to the present embodiment corresponds to the optical member in the present embodiment. Since such a front plate 90 employs the laminated film according to the present embodiment, it has excellent flexibility.

When the display device 100 employs the laminated film according to this embodiment as one or more constituent members selected from the organic EL device 50, the touch sensor 70, and the front plate 90, the display device 100 may have excellent flexibility as a whole. it can. That is, the display device 100 can be a flexible device.

The device (flexible device) to which the laminated film according to the present embodiment can be applied is not limited to the display device. For example, it is also applicable to a solar cell having a substrate on which a photoelectric conversion element is formed and a front plate provided on the substrate surface. In this case, when the laminated film according to the present embodiment is adopted as the substrate or front plate of the solar cell, the solar cell can have excellent flexibility as a whole.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

-Study 1
Example 1
A resin film (silica particle content 60 mass%) containing polyimide and silica particles was prepared as follows based on known literature (for example, United States Patent; Patent No. US8,207,256B2).
An acid anhydride of formula (1), a diamine of formulas (2) and (3), a catalyst, and a solvent (γ-butyrolactone and dimethylacetamide) were charged into a nitrogen-substituted polymerization tank. Charge amount is 75.0 g of acid anhydride of formula (1), 36.5 g of diamine of formula (2), 76.4 g of diamine of formula (3), 1.5 g of catalyst, 438.4 g of γ-butyrolactone, dimethylacetamide 313 0.1 g. The molar ratio of the diamine of the formula (2) and the diamine of the formula (3) was 3: 7, and the molar ratio of the total diamine to the acid anhydride was 1.00: 1.02.

After stirring the mixture in the polymerization tank and dissolving the raw materials in the solvent, the temperature of the mixture was raised to 100 ° C., and then the temperature was raised to 200 ° C. and kept for 4 hours to polymerize the polyimide. During this heating, water in the liquid was removed. Then, the polyimide was obtained by refinement | purification and drying.

Next, a polyimide γ-butyrolactone solution adjusted to a concentration of 20% by mass, a dispersion in which silica particles having a solid content concentration of 30% by mass are dispersed in γ-butyrolactone, and a dimethylacetamide solution of an alkoxysilane having an amino group are mixed, Stir for 30 minutes.

Here, the mass ratio of silica particles to polyimide was 60:40, and the amount of alkoxysilane having an amino group was 1.67 parts by mass with respect to 100 parts by mass in total of silica particles and polyimide.

The mixed solution was applied to a glass substrate and heated at 50 ° C. for 30 minutes and at 140 ° C. for 10 minutes to dry the solvent. Then, the film was peeled from the glass substrate, a metal frame was attached, and the resin film having a thickness of 80 μm was obtained by heating at 210 ° C. for 1 hour.

On one side of the obtained resin film, a two-component curable primer (trade name: Aracoat AP2510, manufactured by Arakawa Chemical Industries, Ltd.) is applied to form a coating film, and the coating film is dried and cured, A primer layer having a thickness of 1 μm was formed.
Next, a functional layer forming solution is applied on the primer layer to form a coating film, and the coating film is dried and cured to have a functional layer having a thickness of 10 μm (having a surface hardness and an ultraviolet absorption function). Layer) to form a laminated film of Example 1. The functional layer-forming solution is 47.5 parts by mass of a tetrafunctional acrylate (trade name: A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.) and a trifunctional acrylate (trade name: A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.) 5 parts by mass, reactive urethane polymer (trade name: 8BR-600, manufactured by Taisei Fine Chemical Co., Ltd., 40% by mass), 12.5 parts by mass, triazine-based ultraviolet absorber (TINUVIN (registered trademark) 479, manufactured by BASF) 3 Parts by mass, photopolymerization initiator (IRGACURE (registered trademark) 184, manufactured by Ciba Specialty Chemicals), 8 parts by mass, leveling agent (trade name: BYK-350, manufactured by Big Chemie Japan), 0.6 parts by mass, and methyl ethyl ketone It prepared by mixing 107 mass parts and stirring.

Comparative Example 1
A functional layer having a thickness of 10 μm was formed on one main surface of a base material (PMMA film) made of polymethyl methacrylate (PMMA) having a thickness of 120 μm in the same manner as in Example 1, and a laminated film of Comparative Example 1 Got.

(Evaluation) Measurement of pencil hardness The pencil hardness of the surface on the functional layer side of the laminated film of Example 1 and Comparative Example 1 was measured according to JIS K5600-5-4. The load for measuring the pencil hardness was 1 kg. The results are shown in Table 1.

Evaluation of Flexibility The laminated films of Example 1 and Comparative Example 1 were cut into a size of 1 cm × 8 cm. The functional layer of the laminated film after cutting was wound on a roll having a radius of r = 1 mm with the surface of the functional layer inside, and the presence or absence of cracks in the laminated film was confirmed. Flexibility was determined according to the following criteria. The results are shown in Table 1.
A: A crack was not cracked and a good appearance was maintained.
C: Five or more cracks occurred.

Optical properties Yellowness (YI value)
The yellowness (Yellow Index: YI value) of the laminated films of Example 1 and Comparative Example 1 was measured with an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation. After measuring the background in the absence of a sample, the laminated film was set in a sample holder, the transmittance was measured for light of 300 nm to 800 nm, and tristimulus values (X, Y, Z) were obtained. The YI value was calculated based on the following formula.
YI value = 100 × (1.28X−1.06Z) / Y
The optical characteristics were determined according to the following criteria. The results are shown in Table 1.
A: YI value is less than 3 C: YI value is 3 or more

Transmittance The transmittance for light of 300 nm to 800 nm was measured using an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation. The transmittance was determined according to the following criteria. The results are shown in Table 1.
A: The transmittance for light having a wavelength of 550 nm is 90% or more. C: The transmittance for light having a wavelength of 550 nm is less than 90%.

Using a fully automatic direct reading haze computer HGM-2DP manufactured by Haze Suga Test Instruments Co., Ltd., the laminated film was set in a sample holder, and the haze of the laminated film was measured. Haze was determined according to the following criteria. The results are shown in Table 1.
A: Haze (%) is less than 1.0% C: Haze (%) is 1.0% or more

Ultraviolet degradation test (QUV test, light irradiation test)
The laminated film was subjected to a QUV test using UVCON manufactured by Atras. The light source was UV-B 313 nm, the output was 40 W, and the distance between the sample (laminated film) and the light source was set to 5 cm. The laminated film was irradiated with ultraviolet rays for 24 hours from the functional layer side.
After the ultraviolet irradiation, the optical characteristics (YI value, transmittance) were evaluated as described above. The results are shown in Table 1.

From the results shown in Table 1, the laminated film of Example 1 is excellent in flexibility. In addition, it was found that the laminated film of Example 1 has functionality such as ultraviolet resistance and surface hardness, and can be used for optical members, display members, and front plates of flexible devices.

-Study 2-
Example 2
Using a polyimide similar to that in Example 1, a γ-butyrolactone solution of polyimide adjusted to a concentration of 20% by mass was prepared. This solution, a solution obtained by dispersing silica particles having a solid content concentration of 30% by mass in γ-butyrolactone, a dimethylacetamide solution of an alkoxysilane having an amino group, and water were mixed and stirred for 30 minutes.

Here, the mass ratio of silica particles and polyimide is 60:40, the amount of alkoxysilane having an amino group is 1.67 parts by mass with respect to 100 parts by mass of silica particles and polyimide, and the amount of water is silica and polyimide. The amount was 10 parts by mass with respect to 100 parts by mass in total.

Using the obtained mixed solution, a laminated film having a resin film, a primer layer, and a functional layer, which were laminated in this order, was obtained in the same manner as in Example 1. However, the thickness of the functional layer was changed to 6 μm.

Example 3
A polyimide having a glass transition temperature of 390 ° C. (“Neoprim” manufactured by Mitsubishi Gas Chemical Company) was prepared. This polyimide γ-butyrolactone solution having a concentration of 20% by mass, a dispersion in which silica particles having a solid content concentration of 30% by mass are dispersed in γ-butyrolactone, a dimethylacetamide solution of alkoxysilane having an amino group, and water are mixed for 30 minutes. A mixed solution was obtained by stirring. The mass ratio of silica particles to polyimide is 55:45, the amount of aminosilane-containing alkoxysilane is 1.67 parts by mass with respect to the total of 100 parts by mass of silica particles and polyimide, and the amount of water is between silica particles and polyimide. It was 10 mass parts with respect to a total of 100 mass parts. Using this mixed solution, a laminated film of Example 3 having a resin film, a primer layer, and a functional layer (thickness: 10 μm) was laminated in this order in the same manner as in Example 1.

Comparative Example 2
The resin film of Example 2 before forming the primer layer and the functional layer was evaluated as a film of Comparative Example 2.

(Evaluation) Optical Properties The films of Example 2 and Comparative Example 2 were subjected to the same QUV test (light irradiation test) as in Study 1. For the film before and after the test, the transmittance, YI value, and haze were measured in the same manner as in Study 1. The difference ΔYI between the YI values before and after the test was also determined. The results are shown in Table 2.

Visibility The film before the light irradiation test was bent, and the appearance such as contrast and hue at that time was confirmed, and the visibility was determined according to the following criteria. The results are shown in Table 2.
A: Contrast and hue change are not recognized.
C: Appearance changes such as changes in contrast and hue were observed.

As shown in Table 2, the laminated film of Example 2 subjected to the light irradiation test satisfies the above-mentioned conditions (i) and (ii), and this laminated film has high visibility when bent. It was confirmed.

－Examination 3-
Example 4
In the same manner as in Example 1, a 75 μm thick resin film (silica particle content 60 mass%) containing polyimide and silica particles was produced.
One main surface of the resin film was subjected to UV ozone treatment. The UV ozone treatment was carried out for 15 minutes using an ultraviolet (UV) ozone cleaning device UV-208 manufactured by Technovision.
Next, an amino group-containing silane coupling agent (3-aminopropyltriethoxysilane, trade name: Z6011, manufactured by Toray Dow Corning Co., Ltd.) is applied to the main surface of the resin film that has been subjected to UV ozone treatment. A primer layer was formed.
Next, a functional layer forming solution is applied onto the primer layer to form a coating film, and the coating film is dried and cured to have a functional layer having a thickness of 5 μm (having surface hardness and ultraviolet absorption function). Layer) to form a laminated film of Example 3. The functional layer-forming solution is 47.5 parts by mass of a tetrafunctional acrylate (trade name: A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.) and a trifunctional acrylate (trade name: A-TMPT, manufactured by Shin-Nakamura Chemical Co., Ltd.) 5 parts by mass, reactive urethane polymer (trade name: 8BR-600, manufactured by Taisei Fine Chemical Co., Ltd., 40% by mass), 12.5 parts by mass, triazine-based ultraviolet absorber (TINUVIN (registered trademark) 479, manufactured by BASF) 3 Parts by mass, photopolymerization initiator (IRGACURE (registered trademark) 184, manufactured by Ciba Specialty Chemicals), 8 parts by mass, leveling agent (trade name: BYK-350, manufactured by Big Chemie Japan), 0.6 parts by mass, and methyl ethyl ketone 107 A mass part was mixed and prepared by stirring.

Reference Example In the same manner as in Example 1, a 75 μm-thick resin film (silica particle content 60 mass%) containing polyimide and silica particles was produced.
Next, a silane coupling agent having an amino group (3-aminopropyltriethoxysilane, trade name: Z6011, manufactured by Toray Dow Corning) was applied to one main surface of the resin film to form a primer layer. .
Subsequently, the functional layer similar to Example 3 was formed on the primer layer, and the laminated film of the reference example was obtained.

Evaluation of Surface Composition of Resin Film The surface subjected to UV ozone treatment in the resin film of Example 3 and one main surface of the resin film of Reference Example were evaluated by an X-ray photoelectron spectroscopy (XPS) method.
For the X-ray photoelectron spectroscopy, an X-ray photoelectron spectrometer (trade name: Quantera SXM, manufactured by ULVAC PHI) was used. X-rays were AlKa (1486.6 eV) and 100 μm in diameter. An electron gun 1 eV and an Ar ion gun 10 eV were used for charging correction. The photoelectron take-off angle was 75 °.
Using the analysis software attached to the apparatus: Multipak V8.2C, the peak area of each element was determined from the obtained XPS spectrum, and the amount of each element on the film surface was calculated in atom% units from the peak area. Furthermore, the atomic ratio (Si / N) of silicon atoms to nitrogen atoms was calculated from the Si2p peak and the N1s peak. The results are shown in Table 3.

Haze The haze (%) of the laminated film was evaluated by the same method as in Study 1. The results are shown in Table 4.

As shown in Table 3, on the surface subjected to the UV ozone treatment in the resin film of Example 4, Si / N, which is the ratio of silicon atoms to nitrogen atoms, was 8.3. On the other hand, it was found that Si / N was 6.5 on one surface of the resin film of the reference example.

Evaluation of Adhesion of Functional Layer The adhesion of the functional layer in the laminated films of Examples and Reference Examples was evaluated by a cross hatch test in accordance with JIS-K5600-5-6. The number of base meshes remaining after peeling the cello tape in a direction of 60 ° with respect to the surface is made by scratching the 10 × 10 base grids at intervals of 2 mm, applying cello tape (registered trademark, manufactured by Nichiban). I counted. Adhesion was determined according to the following criteria. The results are shown in Table 3.
A: The number of remaining grids is 100
C: The number of remaining grids is 99 or less

From the results shown in Table 5, it was found that the laminated film of Example 4 had high adhesion of the functional layer, and the laminated film of Reference Example had low adhesion of the functional layer.

DESCRIPTION OF SYMBOLS 10 ... Resin film, 20 ... Functional layer, 25 ... Primer layer, 30 ... Laminated film, 50 ... Organic EL apparatus, 70 ... Touch sensor, 90 ... Front plate, 100 ... Display apparatus.

Claims (17)

A resin film containing a polyimide polymer;
A functional layer provided on at least one main surface of the resin film;
A laminated film comprising: The laminated film according to claim 1, wherein the resin film further contains a silicon material containing a silicon atom. The laminated film according to claim 2, wherein the silicon material is silica particles. When a light irradiation test for irradiating the laminated film with light of 313 nm from the functional layer side for 24 hours by a light source with an output of 40 W provided at a distance of 5 cm from the laminated film, the laminated film is as follows. conditions:
(I) The laminated film after the light irradiation test has a transmittance of 85% or more for light of 550 nm, and
(Ii) The laminated film before the light irradiation test has a yellowness of 5 or less, and the difference in yellowness before and after the light irradiation test of the laminated film is less than 2.5.
The laminated film according to any one of claims 1 to 3, which satisfies the following conditions. The laminated film according to claim 4, wherein the laminated film after light irradiation has a haze of 1.0% or less. A resin film containing a polyimide-based polymer and a silicon material containing silicon atoms, wherein Si / N, which is the atomic ratio of silicon atoms to nitrogen atoms on at least one main surface, is 8 or more. The resin film according to claim 6, wherein the silicon material is silica particles. The resin film according to claim 6 or 7,
A functional layer provided on the main surface side of the resin film having Si / N of 8 or more;
A laminated film comprising: 9. The layer according to claim 1, wherein the functional layer is a layer having at least one function selected from the group consisting of ultraviolet absorption, surface hardness, adhesiveness, hue adjustment, and refractive index adjustment. A laminated film according to 1. The laminated film according to any one of claims 1 to 5 and 8, wherein the functional layer is a layer having a function of at least one of ultraviolet absorption and surface hardness. The laminated film according to any one of claims 1 to 5 and 8 to 10, further comprising a primer layer provided between the resin film and the functional layer. The laminated film according to claim 11, wherein the primer layer contains a silane coupling agent. The laminated film according to claim 12, wherein the silane coupling agent has at least one substituent selected from the group consisting of a methacryl group, an acryl group, and an amino group. A step of performing UV ozone treatment on at least one principal surface of a resin film containing a polyimide-based polymer and a silicon material containing a silicon atom;
Providing a functional layer on the main surface side of the resin film that has been subjected to the UV ozone treatment;
A method for producing a laminated film. An optical member comprising the laminated film according to any one of claims 1 to 5 and 8 to 13. A display member comprising the laminated film according to any one of claims 1 to 5 and 8 to 13. A front plate comprising the laminated film according to any one of claims 1 to 5 and 8 to 13.

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