TWI694096B - Front panel of flexible device - Google Patents

Abstract

This invention provides a resin film 10 containing polyimides polymer, while conducting an light exposing test for exposing a predetermined light from a main surface 10a to the resin film 10, the resin film satisfies the following conditions of: (i) the resin film after light exposing test has a transparency of 85% or more to a light with a wavelength of 550nm; and (ii) the resin film before light exposing test has a yellowness of 5 or less, and the difference of yellowness of the resin film before and after the light exposing test is less than 2.5.

Description

Front panel of flexible device

The present invention relates to a resin film, a laminate, an optical member, a display member, and a front panel.

Conventionally, glass has been used as a base material for a display member, an optical member base material, and a front panel constituting various display devices such as solar cells and displays. However, the glass system has the disadvantages of being easy to crack and being heavy. In addition, in recent years, when the display is thinner, lighter, and more flexible, the glass substrate or the glass front panel does not have sufficient material properties. For this reason, acrylic resins and laminates that impart scratch resistance to resins have been studied as materials or base materials for replacing glass. Composite materials of organic materials and inorganic materials such as mixed films containing polyimide and silicon oxide have also been studied (for example, refer to Patent Documents 1 and 2).

Prior technical literature Patent Literature

[Patent Document 1] Japanese Patent Laid-Open No. 2008-163309

[Patent Document 2] Specification of US Patent No. 8207256

According to the findings of the inventors of the present application, a resin film containing a polyimide-based polymer has high transparency and can achieve excellent flexibility. However, the resin film containing a polyimide-based polymer may sometimes change in contrast and hue during bending, and in this regard, it must be further improved. The resin film used for the substrate of the display device of the flexible device, the substrate of the optical member, and/or the front panel is required to have good visibility when bent.

Therefore, the main object of the present invention is to improve the visibility during bending of a resin film containing a polyimide-based polymer and having high transparency.

The resin film of one aspect of the present invention contains a polyimide-based polymer. With a light source installed at a distance of 5 cm from the resin film and having an output power of 40 W, the resin film was irradiated with 313 nm light from one side of the resin film for 24 hours, and the resin film satisfies the following conditions .

(i) The resin film after the light irradiation test has a transmittance of 85% or more to light at 550 nm; and (ii) The resin film before the light irradiation test has a yellowness of 5 or less, and the resin film The difference in yellowness before and after the light irradiation test was less than 2.5.

When the resin film that satisfies these conditions (i) and (ii) is bent, Contrast or hue is not easy to change, but can maintain good visibility.

The present invention provides a laminate including the above-mentioned resin film and a functional layer provided on at least one surface side of the resin film. The functional layer may be a layer having at least one function selected from the group consisting of the functions of ultraviolet absorption, adhesion, and high hardness on the surface.

The above laminate may further have an undercoat layer provided between the resin film and the functional layer.

The substrate of the optical member or the display member and the front panel according to an aspect of the present invention include the above-mentioned resin film or laminate. When these are applied to flexible devices, they can contribute to excellent visibility during bending.

According to the present invention, regarding a resin film containing a polyimide-based polymer, the visibility during bending can be improved.

10‧‧‧Resin film

10a, 10b‧‧‧Main

20‧‧‧Functional layer

25‧‧‧ Primer coating

25a‧‧‧Main

30‧‧‧Layered body (Layered body)

50‧‧‧ organic EL device

51‧‧‧ organic EL element

52‧‧‧First electrode

53‧‧‧Second electrode

54‧‧‧luminous layer

55‧‧‧ First substrate

56‧‧‧Second substrate

59‧‧‧Sealing material

70‧‧‧Touch sensor

71‧‧‧Touch sensor substrate

72‧‧‧Element layer

90‧‧‧Front panel

100‧‧‧Display device

Fig. 1 is a cross-sectional view showing an embodiment of a resin film.

Fig. 2 is a cross-sectional view showing an embodiment of the laminate.

Fig. 3 is a cross-sectional view showing an embodiment of the laminate.

FIG. 4 is a schematic cross-sectional view showing an embodiment of a display device.

(Form for carrying out the invention)

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In each figure, the same Or the corresponding element may be attached with the same symbol, omitting the repeated description.

[Resin Film]

Fig. 1 is a cross-sectional view showing an embodiment of a resin film. The resin film 10 shown in FIG. 1 contains a polyimide-based polymer and has a pair of opposed main surfaces 10a and 10b.

With a light source with a power output of 40 W installed at a distance of 5 cm from the resin film 10, the resin film 10 was irradiated with light of 313 nm for 24 hours from the main surface 10a side. The resin film 10 satisfies the following conditions: (i) The resin film after the light irradiation test has a transmittance of 85% or more to light at 550 nm; and (ii) The resin 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 this resin film was less than 2.5. The resin film that satisfies these conditions (i) and (ii) does not easily change in contrast or hue during bending, and can maintain good visibility.

The resin film that satisfies the conditions (i) and (ii) can be easily obtained, for example, by using a polyimide-based polymer having high transparency and including an ultraviolet absorber in the resin film. Specific examples of polyimide-based polymers and ultraviolet absorbers with high transparency will be described later.

After the light irradiation test, the transmittance of the resin film 10 to light of 550 nm is preferably 90% or more, and usually 100% or less. Below 95%. The haze of the resin film 10 after the light irradiation test is preferably 0.9 or less, and may also be 0.1 or more. The resin film 10 before the light irradiation test may have a transmittance of more than 85% to 550 nm light. The transmittance of the resin film to light of a predetermined wavelength means the ratio of the light intensity of the same wavelength after transmitting the resin film with respect to the light intensity of the predetermined wavelength of the incident resin film. The haze system can be measured in accordance with JIS K 7105:1981. The detailed measurement method of transmittance and haze will be described in Examples described later.

The yellowness of the resin film 10 before the light irradiation test is preferably 4 or less, preferably 3 or less, or may be 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 between the yellowness before and after the light irradiation test of the resin film △YI is based on the formula "△YI=YI ₁ -YI ₀ ". The △YI system is preferably 2.3 or less, preferably 2.0 or less, and may also be 0.1 or more. The detailed measurement method of the yellowness will be described in Examples described later.

The resin film 10 contains a polyimide polymer. In this specification, a polyimide-based polymer means a polymer having at least one or more repeating structural units represented by formula (PI), formula (a), formula (a'), or formula (b) . From the viewpoint of the strength and transparency of the film, the main structure of the repeating structural unit system polyimide-based polymer represented by the formula (PI) is preferable in a single case. With respect to the total repeating structural units of the polyimide-based polymer, the repeating structural unit represented by the formula (PI) is preferably 40 mol% or more, preferably 50 mol% or more, and more preferably 70 mol More than 90%, more preferably 90 mole%, more preferably 98 mole%.

The G system in the formula (PI) represents a tetravalent organic group, and the A system represents a divalent organic group. The G ² series in formula (a) represents a trivalent organic group, and the A ² series represents a divalent organic group. The G ³ series in formula (a′) represents a tetravalent organic group, and the A ³ series represents a divalent organic group. G ⁴ and A ⁴ in formula (b) each represent a divalent organic group.

In formula (PI), the organic as tetravalent organic group represented by G The group (hereinafter referred to as an organic group called G) may be a group selected from the group consisting of acyclic aliphatic groups, cyclic aliphatic groups, and aromatic groups. From the viewpoint of transparency and flexibility of the resin film 10, the organic group of G is preferably a tetravalent cyclic aliphatic group or a tetravalent aromatic group. Examples of the aromatic group include a monocyclic aromatic group, a condensed polycyclic aromatic group, and two or more aromatic rings, and these are non-condensed groups which are directly or mutually connected by a bonding group Polycyclic aromatic groups. From the viewpoints of transparency of the resin film and suppression of coloring, the organic group of G is a cycloaliphatic group, a cyclic aliphatic group having a fluorine-based substituent, and a monocyclic aromatic group having a fluorine-based substituent 2. A condensed polycyclic aromatic group having a fluorine-based substituent or a non-condensed polycyclic aromatic group having a fluorine-based substituent is preferred. In this specification, the fluorine-based substituent means a group containing a fluorine atom. The fluorine-based substituent system is preferably a fluorine group (fluorine atom, -F) and a perfluoroalkyl group, more preferably a fluorine group and a trifluoromethyl group.

More specifically, the organic group of G can be selected from, for example, saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl, aryl, heteroaryl, arylalkyl, alkylaryl, heteroalkane A aryl group, and any two of these groups (which may also be the same) and these are groups that are directly or mutually connected by a bonding group. Examples of the bonding group include -O-, alkylene having 1 to 10 carbon atoms, -SO ₂ -, -CO-, or -CO-NR- (R represents methyl, ethyl, propyl, etc. (C1-C3 alkyl group or hydrogen atom).

The carbon number of the tetravalent organic group represented by G is usually 2 to 32, preferably 4 to 15, preferably 5 to 10, and more preferably 6 to 8. When the organic group of G is a cyclic aliphatic group or an aromatic group, the carbon atoms constituting these groups At least one of them may be replaced by a hetero atom. Examples of heteroatoms include O, N, and S.

Specific examples of G include the groups represented by the following formula (20), formula (21), formula (22), formula (23), formula (24), formula (25), or formula (26). The * in the formula represents the dangling bond. Z in formula (26) represents 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-. Ar represents an aryl group having 6 to 20 carbon atoms, and may also be an alkylene group, for example. At least one of the hydrogen atoms of these groups may be substituted with a fluorine-based substituent.

In the formula (PI), the organic group of a divalent organic group represented by A (hereinafter sometimes referred to as an organic group of A) may be selected from the group consisting of acyclic aliphatic groups, cycloaliphatic groups, and aromatic groups. The basis of the group formed by the basis. The divalent organic group represented by A is preferably selected from a divalent cyclic aliphatic group and a divalent aromatic group. As the aromatic group, a monocyclic aromatic group, a condensed polycyclic aromatic group, and two or more aromatic rings are mentioned and these are straight A non-condensed polycyclic aromatic group formed by connecting or connecting to each other by a bonding group. From the viewpoint of transparency of the resin film and suppression of coloration, the organic group of A is preferably introduced with a fluorine-based substituent.

More specifically, the organic group of A is, for example, selected from saturated or unsaturated cycloalkyl, saturated or unsaturated heterocycloalkyl, aryl, heteroaryl, arylalkyl, alkylaryl, heteroalkyl An aryl group, and any two of these groups (which may be the same) and these are groups that are directly or mutually connected by a bonding group. Examples of the hetero atom include O, N or S, and examples of the bonding group include -O-, an alkylene group having 1 to 10 carbon atoms, -SO ₂ -, -CO- or -CO-NR-( R series contains a C1-C3 alkyl group or hydrogen atom, such as a methyl group, an ethyl group, a propyl group, etc.).

The carbon number of the divalent organic group represented by A is usually 2 to 40, preferably 5 to 32, preferably 12 to 28, and more preferably 24 to 27.

Specific examples of A include the groups represented by the following formula (30), formula (31), formula (32), formula (33), or formula (34). The * in the formula represents the dangling bond. Z ¹ to Z ³ are each independent and represent a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO-, or -CO-NR- (R is methyl , Ethyl, propyl and other alkyl groups having 1 to 3 carbon atoms or hydrogen atoms). In the following groups, Z ¹ and Z ² and Z ² and Z ³ are preferably meta or para to each ring. 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 preferably meta or para. In an example of A, Z ¹ and Z ³ are -O-, and Z ² is -CH ₂ -, -C(CH ₃ ) ₂ -, or -SO ₂ -. One or more hydrogen atoms of these groups may also be substituted with fluorine-based substituents.

At least one hydrogen atom among the hydrogen atoms constituting at least one of A and G may also be selected from the group consisting of a fluorine-based substituent, a hydroxyl group, a sulfonic acid group, and a C 1-10 alkyl group, etc. At least one functional group is substituted. When the organic group of A and the organic group of G are each a cycloaliphatic group or an aromatic group, it is preferred that at least one of A and G has a fluorine-based substituent, and that both A and G have a fluorine-based substitution The base is better.

G ² in formula (a) is a trivalent organic group. This organic group can be selected from the same groups as the organic group of G in the formula (PI) except for the trivalent group. As an example of G ² , among the four dangling bonds of the groups represented by Formula (20) to Formula (26) that have been given as specific examples of G, any one of them may be replaced with a hydrogen atom. The A ² system 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 the organic group of G in formula (PI). The A ³ system in formula (a′) can be selected from the same groups as A in formula (PI).

G ⁴ in formula (b) is a divalent organic group. This organic group can be selected from the same groups as the organic group of G in the formula (PI) except for the point of the divalent group. As an example of G ⁴ , among the four dangling bonds of the groups represented by Formula (20) to Formula (26) that have been given as specific examples of G, any two of them may be replaced by hydrogen atoms. The A ⁴ series in formula (b) can be selected from the same groups as A in formula (PI).

The polyimide-based polymer contained in the resin film 10 may be a tetracarboxylic acid compound analog made by using diamines and a tetracarboxylic acid compound (including an acetyl chloride compound and a tetracarboxylic dianhydride) ) Or at least one type of tricarboxylic acid compound (tricarboxylic acid compound analogs including an acetyl chloride compound and tricarboxylic anhydride) is a condensation-type polymer obtained by polycondensation. Furthermore, polycondensation can also be performed on dicarboxylic acid compounds (including analogues such as acetyl chloride compounds). The repeating structural unit represented by formula (PI) or formula (a') is usually derived from diamines and tetracarboxylic acid compounds. The repeating structural unit represented by formula (a) is usually derived from diamines and tricarboxylic acid compounds. The repeating structural unit represented by formula (b) is usually derived from diamines and dicarboxylic acid compounds.

Examples of the tetracarboxylic acid compound include an aromatic tetracarboxylic acid compound, an alicyclic tetracarboxylic acid compound, and an acyclic aliphatic tetracarboxylic acid compound. Two or more of these can also be used in combination. The tetracarboxylic acid compound is preferably tetracarboxylic dianhydride. Examples of the tetracarboxylic dianhydride include aromatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and acyclic aliphatic tetracarboxylic dianhydride. anhydride.

From the viewpoints of the solubility of the polyimide-based polymer in the solvent and the transparency and flexibility after forming the resin film 10, the tetracarboxylic acid compound is selected from the group consisting of alicyclic tetracarboxylic acid compounds and aromatic tetracarboxylic acid compounds Carboxylic acid compound Good is better. From the viewpoints of transparency of the resin film and suppression of coloration, the tetracarboxylic acid compound is preferably selected from an alicyclic tetracarboxylic acid compound having a fluorine-based substituent and an aromatic tetracarboxylic acid compound having a fluorine-based substituent The alicyclic tetracarboxylic acid compound having a fluorine-based substituent is more preferable.

Examples of the tricarboxylic acid compound include aromatic tricarboxylic acids, alicyclic tricarboxylic acids, non-cyclic aliphatic tricarboxylic acids, and similar acetyl chloride compounds and acid anhydrides. The tricarboxylic acid compound is preferably selected from aromatic tricarboxylic acids, alicyclic tricarboxylic acids, non-cyclic aliphatic tricarboxylic acids, and similar acetyl chloride compounds. Two or more tricarboxylic acid compounds may be used in combination.

From the viewpoint of the solubility of the polyimide-based polymer in the solvent and the transparency and flexibility of the resin film 10, the tricarboxylic acid compound is selected from the group consisting of alicyclic tricarboxylic acid compounds and aromatic tricarboxylic acids Acid compounds are preferred. From the viewpoint of transparency of the resin film and suppression of coloration, the tricarboxylic acid compound is preferably selected from 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 acids, alicyclic dicarboxylic acids, non-cyclic aliphatic dicarboxylic acids, and similar acetyl chloride compounds and acid anhydrides. The dicarboxylic acid compound is preferably selected from aromatic dicarboxylic acids, alicyclic dicarboxylic acids, non-cyclic aliphatic dicarboxylic acids, and similar acetyl chloride compounds. Two or more dicarboxylic acid compounds may be used in combination.

From the viewpoints of the solubility of the polyimide-based polymer in the solvent and the transparency and flexibility of the resin film 10, the dicarboxylic acid compound is selected from the group consisting of alicyclic dicarboxylic acid compounds and aromatic dicarboxylic acids Carboxylic acid compounds are preferred. From the viewpoint of transparency of the resin film and suppression of coloring, two The carboxylic acid compound is preferably selected from an alicyclic dicarboxylic acid compound having a fluorine-based substituent and an aromatic dicarboxylic acid compound having a fluorine-based substituent.

Examples of the diamines include aromatic diamines, alicyclic diamines, and aliphatic diamines. Two or more of these can also be used in combination. From the viewpoint of the solubility of the polyimide-based polymer in the solvent and the transparency and flexibility of the resin film 10, the diamines are selected from those having an alicyclic diamine and having a fluorine-based substituent Aromatic diamines are preferred.

When such a polyimide-based polymer is used, it is easy to obtain particularly excellent flexibility and high light transmittance (for example, 85% or more, preferably 88% or more for 550 nm light), and low yellow Resin film with a degree (YI value of, for example, 5 or less, preferably 3 or less), and a low haze (for example, 1.5% or less, preferably 1.0% or less).

The polyimide-based polymer may also contain a plurality of different types of copolymers containing the aforementioned repeating structural units. The weight average molecular weight of the polyimide-based polymer is usually 10,000 to 500,000. The weight average molecular weight of the polyimide-based polymer is preferably 50,000 to 500,000, preferably 70,000 to 400,000. The weight average molecular weight is a standard polystyrene-equivalent molecular weight measured using gel permeation chromatography (GPC). When the weight average molecular weight of the polyimide-based polymer is large, it tends to be easily obtained with high flexibility. When the weight average molecular weight of the polyimide-based polymer is too large, the viscosity of the varnish becomes high and processing Tendency to decline.

The polyimide-based polymer may contain a halogen atom such as a fluorine atom that can be introduced through the above-mentioned fluorine-based substituent or the like. Since the polyimide-based polymer contains halogen atoms, the elastic modulus of the resin film can be made Increase and reduce the yellowness. With this, it is possible to suppress damage, wrinkles, and the like generated in the resin film, and to improve the transparency of the resin film. The halogen atom system is preferably a fluorine atom. The content of halogen atoms in the polyimide-based polymer is based on the mass of the polyimide-based polymer as a reference, preferably 1 to 40% by mass, and more preferably 1 to 30% by mass.

系化合物所組成群組之至少1種化合物。 The resin film 10 may contain one kind or two or more kinds of ultraviolet absorbers. The ultraviolet absorber system can be appropriately selected from those generally used as ultraviolet absorbers in the field of resin materials. The ultraviolet absorber may also contain a compound that absorbs light with a wavelength below 400 nm. Examples of the ultraviolet absorber that can be appropriately combined with the polyimide-based polymer include, for example, diphenyl ketone-based compounds, salicylate-based compounds, benzotriazole-based compounds, and triazoles.

It is at least one compound in the group of compounds.

In this specification, the term "system compound" refers to a derivative of the compound to which the "system compound" is added. For example, the "diphenyl ketone-based compound" refers to a compound having a diphenyl ketone as a parent skeleton and a substituent bonded to the diphenyl ketone.

The formulation amount of the ultraviolet absorber may be as long as the resin film 10 can satisfy the above conditions (i) and (ii). Specifically, with respect to the total mass of the resin film, the amount of the ultraviolet absorber is usually 1% by mass or more, preferably 2% by mass or more, preferably 3% by mass or more, usually 10% by mass or less, 8% by mass The following is preferred, and 6% by mass or less is preferred.

The resin film 10 may further contain inorganic materials such as inorganic particles. The inorganic material is preferably a silicon material containing silicon atoms. Since the resin film 10 contains an inorganic material such as silicon material, in terms of flexibility, it can be Enough to obtain particularly excellent results.

Examples of the silicon material containing silicon atoms include silicon oxide particles, silicon compounds such as quaternary alkoxysilanes such as tetraethyl orthosilicate (TEOS), and silsesquioxane derivatives. Among these silicon materials, silicon oxide particles are preferred from the viewpoint of transparency and flexibility of the resin film 10.

The average primary particle size of silicon oxide particles is usually below 100 nm. When the average primary particle size of the silicon oxide particles is 100 nm or less, the transparency tends to increase.

The average primary particle diameter of the silicon oxide particles in the resin film can be determined by observation through a transmission electron microscope (TEM). The primary particle size of the silicon oxide particles can be set as a fixed diameter by a transmission electron microscope (TEM). The average primary particle size can be determined by TEM observation to measure the primary particle size at 10 points and obtain the average value of these. The particle distribution of the silicon oxide particles before forming the resin film can be obtained using a commercially available laser diffraction particle size distribution meter.

In the resin film 10, the compounding ratio of the polyimide-based polymer and the inorganic material, the total of the two is set to 10, and the mass ratio is preferably 1:9 to 10:0, and 3:7 to 10:0 is better, 3:7 to 8:2 is better, and 3:7 to 7:3 is even better. The ratio of the inorganic material relative to the total mass of the polyimide-based polymer and the inorganic material is usually 20% by mass or more, preferably 30% by mass or more, usually 90% by mass or less, and preferably 70% by mass or less. When the blending ratio of the polyimide-based polymer and the inorganic material is within the above range, the transparency and mechanical strength of the resin film are improved tendency.

The resin film 10 further contains other components within a range that does not significantly impair transparency and flexibility. Examples of other components include coloring agents such as antioxidants, mold release agents, stabilizers, and blueing agents, flame retardants, slip agents, and leveling agents. The ratio of components other than the polyimide-based polymer and the inorganic material is preferably more than 0% and 20% by mass or less, and preferably more than 0% and 10% by mass or less relative to the mass of the resin film 10.

When the resin film 10 contains a polyimide-based polymer and a silicon material, the atomic ratio of silicon atoms to nitrogen atoms on at least one main surface 10a, which is Si/N, is preferably 8 or more. The atomic number ratio Si/N is a value calculated by evaluating the composition of the main surface 10a by X-ray photoelectron spectroscopy (X-ray Photoelectron Spectroscopy, XPS), and from the thus obtained amount of silicon atoms and nitrogen atoms.

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

The thickness of the resin film 10 can be appropriately adjusted according to the flexible device to which the laminate 30 is applied, preferably 10 to 500 μm, preferably 15 to 200 μm, and more preferably 20 to 100 μm. The resin film 10 having such a structure has particularly excellent flexibility.

Next, an example of a method of manufacturing the resin film 10 of this embodiment will be described. Polyimide series used in the production of resin films is high The molecular varnish can be prepared by dissolving a polyimide-based polymer which can be dissolved in a solvent by a polymerization method using a conventional polyimide-based polymer and is dissolved in a solvent. The solvent type may be a solvent that can dissolve the polyimide-based polymer, for example, dimethylacetamide (DMAC), dimethylformamide (DMF), dimethylsulfoxide (DMSO), γ -Butyrolactone (GBL), and mixed solvents of these.

When manufacturing a resin film containing an inorganic material, an inorganic material is added to the polyimide-based polymer varnish and stirred and mixed using a conventional stirring method to prepare a dispersion liquid in which the inorganic material is uniformly dispersed. When blending an ultraviolet absorber, it is possible to add an ultraviolet absorber to the dispersion.

。 The polyimide-based polymer varnish or dispersion liquid may further contain additives. Examples of the additives include coloring agents such as antioxidants, release agents, stabilizers, and blueing agents, flame retardants, slip agents, tackifiers, and leveling agents. The polyimide-based polymer varnish or dispersion may also contain compounds such as alkoxysilanes having one or more alkoxide metal groups that contribute to the bonding between inorganic particles. Examples of such compounds include alkoxysilanes having amine groups. By using a polyimide-based polymer varnish or dispersion containing such a compound, it is possible to increase the mixing ratio of inorganic particles while maintaining optical properties such as transparency of the resin film

.

The polyimide-based polymer varnish or dispersion liquid may further contain water. The water content is usually 0.1 to 10% by mass relative to the mass of the polyimide-based polymer varnish or dispersion.

The resin film system can be manufactured using an appropriate conventional method. As an example of the manufacturing method, the following method may be mentioned. The above-mentioned polyimide-based polymer varnish or dispersion liquid is applied to a substrate using a conventional winding method and batch method to form a coating film. The coating film was dried to form a thin film. Subsequently, the resin film 10 is obtained by peeling the film from the substrate. Examples of the base material include polyethylene terephthalate (PET) base materials, stainless steel (SUS) belts, and glass base materials.

For drying and/or baking of the coating film, the coating film may be heated. The heating temperature of the coating film is usually 50 to 350°C. The heating of the coating film can also be performed under an inert environment or under reduced pressure. By heating the coating film, the solvent can be evaporated and removed. The resin film can be formed by a method including the following steps: a step of drying the coating film at 50 to 150°C; and a step of baking the dried coating film at 180 to 350°C.

Secondly, surface treatment may be performed on at least one main surface of the resin film. The surface treatment system is preferably UV ozone treatment. By UV ozone treatment, Si/N can easily become 8 or more. However, the method of making Si/N 8 or more is not limited by UV ozone treatment. The main surface 10a and/or 10b of the resin film 10 may also be subjected to surface treatment such as plasma treatment or corona discharge treatment to improve adhesion to the functional layer described later.

The UV ozone treatment system can use a conventional ultraviolet light source including a wavelength of 200 nm or less. As an example of the ultraviolet light source, a low-pressure mercury lamp can be mentioned. As the ultraviolet light source, various commercially available devices equipped with an ultraviolet light source can also be used. Commercially available devices include, for example, ultraviolet (UV) ozone cleaning device UV-208 manufactured by TECHNOVISION.

The resin film 10 of the present embodiment obtained in this way has excellent flexibility. In addition, when at least one main surface 10a has an atomic ratio of silicon atoms to nitrogen atoms, that is, Si/N of 8 or more, excellent adhesion to the functional layer 20 described below can be obtained.

[Laminate]

Fig. 2 is a cross-sectional view showing an embodiment of the laminate. The laminate 30 shown in FIG. 2 is a laminate having a resin film 10 and a functional layer 20, wherein the functional layer 20 is laminated on one main surface 10a of the resin film 10.

When the laminated body 30 is used as an optical member of a flexible device, a substrate of a display member, or a front panel, the functional layer 20 can be a layer for further imparting function (performance) to the laminated body 30. Here, in this specification, the optical member means a sensor part or a signal transmission part such as a touch sensor of a display device, and the display member means an organic EL device or a liquid crystal display of the display device An image display unit such as a device.

The functional layer 20 preferably has at least one function selected from the group consisting of the function of absorbing ultraviolet rays to make the surface exhibit high hardness, adhesion, hue adjustment, and refractive index adjustment.

The layer having an ultraviolet absorbing function (ultraviolet absorbing layer) as the functional layer 20 is composed of, for example, a main material and an ultraviolet absorbing agent dispersed in the main material, wherein the main material is selected from an ultraviolet curing type transparent resin, electron beam Curable transparent resin and thermosetting transparent resin. By providing an ultraviolet absorbing layer as the functional layer 20, it is possible to easily suppress the change in yellowness caused by light irradiation.

The ultraviolet curing type, electron beam curing type, or thermosetting type transparent resin system that is the main material of the ultraviolet absorption layer is not particularly limited, and for example, it may be poly(meth)acrylate. The ultraviolet absorber system can be selected from compounds similar to those exemplified as ultraviolet absorbers that can be contained in the resin film 10.

The ultraviolet absorption layer may be a layer that absorbs light of a wavelength of 400 nm or less (for example, light of a wavelength of 313 nm) by 95% or more. In other words, the ultraviolet absorbing layer may be a layer having a transmittance of less than 5% for light with a wavelength of 400 nm or less (for example, light with a wavelength of 313 nm). The ultraviolet absorbing layer can contain an ultraviolet absorber in a concentration that can achieve such transmittance. From the viewpoint of suppressing the increase in the yellowness of the laminate due to light irradiation, the content ratio of the ultraviolet absorber in the ultraviolet absorption layer (functional layer 20) is based on the mass of the ultraviolet absorption layer, and is usually 1% by mass or more It is preferably 3% by mass or more, usually 10% by mass or less, and preferably 8% by mass or less.

As the functional layer 20, a layer (a hard coat layer) having a function for rendering the surface high in hardness is, for example, a layer provided with a surface having a pencil hardness higher than that of the resin film surface to the laminate. The hard coat system is not particularly limited, and includes ultraviolet (curable), electron beam curable, or thermosetting resins represented by poly(meth)acrylates. The hard coat layer may also contain a photopolymerization initiator and an organic solvent. Poly(meth)acrylates are, for example, one or more selected from polyurethane (meth)acrylate, epoxy (meth)acrylate, and other multifunctional poly(meth)acrylates Poly(meth)acrylates formed from (meth)acrylates. The hard coat system may contain silicon oxide, aluminum oxide, polyorganosiloxane, etc. in addition to the above components Of inorganic oxides.

The layer having an adhesive function (adhesive layer) as the functional layer 20 has a function of making the laminated body 30 continue to other members. As a material for forming the adhesive layer, for example, a thermosetting resin composition or a photocurable resin composition can be mentioned.

The adhesive layer may also be composed of a resin composition containing a component having a polymerizable functional group. At this time, after adhering the laminate 30 to other members, by further polymerizing the resin composition constituting the adhesive layer, a strong bond can be achieved. The adhesive strength between the resin film 10 and the adhesive layer is preferably 0.1 N/cm or more, and more preferably 0.5 N/cm or more.

The adhesive layer may also contain a thermosetting resin composition or a photocurable resin composition as a material. At this time, by supplying energy afterwards, the resin composition can be polymerized and hardened.

The adhesive layer may also be a layer called pressure sensitive adhesive (Pressure Sensitive Adhesive, PSA) attached to the object by pressing. The pressure-sensitive adhesive can be "adhesive at room temperature and adhere to the adherend with lighter pressure" (JIS K6800), or "contain specific components in a protective film (micro (Capsule), and can maintain stability until the adhesive is destroyed by appropriate means (pressure, heat, etc.) (JIS K6800) capsule type adhesive.

As the functional layer 20 having a hue adjustment function (hue adjustment layer), the layered body 30 can be adjusted to a target hue layer. The hue adjustment layer may be, for example, a layer containing resin and coloring agent. Examples of the colorant include titanium oxide, zinc oxide, iron oxide red, and titanium oxide Inorganic pigments such as calcined pigments, ultramarine blue, cobalt aluminate and carbon black; azo compounds, quinacridone compounds, anthraquinone compounds, perylene compounds, isoindolinone compounds , Organic pigments such as phthalocyanine compounds, quinophthalone compounds, threne compounds and diketopyrrolopyrrole compounds; physical pigments such as barium sulfate and calcium carbonate; basic dyes, Dyes such as acid dyes and mordant dyes.

The layer having a refractive index adjustment function (refractive index adjustment layer) as the functional layer 20 is a layer having a different refractive index from the resin film 10 and capable of imparting a predetermined refractive index to the laminate. The refractive index adjustment layer may be, for example, a resin layer containing a suitably selected resin and, if necessary, a pigment, or 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 size of the pigment is preferably 0.1 μm or less. By setting the average particle diameter of the pigment to 0.1 μm or less, it is possible to prevent the light transmitted through the refractive index adjustment layer from being diffusely reflected and to prevent the transparency from being lowered.

Examples of the metal used in the refractive index adjustment layer include titanium oxide, tantalum oxide, zirconium oxide, zinc oxide, tin oxide, silicon oxide, indium oxide, titanium oxynitride, titanium nitride, silicon oxynitride, and nitrogen Metal oxides or metal nitrides such as silicon.

The functional layer 20 suitably has the above-mentioned functions according to the application of the laminate 30. The functional layer 20 may be a single layer or a plurality of layers. Each layer can have one function or more than two functions.

The functional layer 20 preferably has a function to make the surface have high hardness and an ultraviolet absorption function. In this case, the functional layer 20 is preferably composed of the following: "a single layer having a function of showing high hardness on the surface and ultraviolet absorbing function", "a layer having a function of showing high hardness on the surface and a layer having ultraviolet absorption "Multilayers of layers", or "multilayers including a single layer having a function of showing high hardness on the surface and a function of absorbing ultraviolet rays and a layer having a function of showing high hardness on the surface".

The thickness of the functional layer 20 can be adjusted appropriately according to the flexible device to which the laminate 30 is applied, preferably 1 to 100 μm, more preferably 2 to 80 μm. Typically, the functional layer 20 is thinner than the resin film 10.

The laminate 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 using conventional winding and batch methods.

As the ultraviolet absorbing layer of the functional layer 20, for example, a coating film can be formed by applying a dispersion liquid of a main material containing an ultraviolet absorber and a resin dispersing the ultraviolet absorber on the main surface 10a of the resin film 10, and This coating film is formed by drying and hardening.

The hard coat layer of the functional layer 20 can be formed by, for example, applying a solution containing a resin for forming a hard coat layer to the main surface 10a of the resin film 10, and drying and hardening the coat film.

The adhesive layer as the functional layer 20 can be formed, for example, by applying a solution containing an adhesive that forms the adhesive layer on the main surface 10a of the resin film 10, and drying and hardening the coating film.

The hue adjustment layer of the functional layer 20 can be formed by, for example, coating the main surface 10a of the resin film 10 with a dispersion liquid containing a main material such as a pigment that forms a hue adjustment layer, and a resin that disperses the pigment or the like. Film, and the coating film is dried and hardened to form.

The refractive index adjustment layer of the functional layer 20 can be dispersed, for example, by coating the main surface 10a of the resin film 10 with a main material containing inorganic particles and the like forming the refractive index adjustment layer, and a resin and the like dispersing the inorganic particles and the like Liquid to form a coating film, and the coating film is dried and hardened to form.

As a single layer of the functional layer 20 which has a function of showing high hardness on the surface and has an ultraviolet absorbing function, it can coat the main surface 10a of the resin film 10 with a main material containing an ultraviolet absorber, a resin dispersing the ultraviolet absorber, etc. And a dispersion of resin forming a hard coat layer to form a coating film, and the coating film is dried and hardened to form. The resin used as the main material and the resin forming the hard coat layer can also be the same.

A multi-layer functional layer including a layer having a function to make the surface have high hardness and a layer having an ultraviolet absorption layer can be formed using the following method.

On the main surface 10a of the resin film 10, a dispersion liquid containing a main material such as an ultraviolet absorber and a resin dispersing the ultraviolet absorber is applied to form a coating film, and the ultraviolet absorption layer is formed by drying and curing the coating film. Next, a solution containing the resin forming the hard coat layer is applied to the ultraviolet absorbing layer to form a coating film, and the hard coat layer is formed by drying and hardening the coating film. Using this method, it is possible to form a multi-layer functional layer including a layer having a function of rendering the surface high in hardness and a layer having an ultraviolet absorption layer.

A multi-layer including a single layer having a function of showing high hardness on the surface and a layer having a function of absorbing ultraviolet rays and a layer having a function of showing high hardness on the surface can be formed using the following method.

The main film 10a of the resin film 10 may be coated with a dispersion of a main material containing an ultraviolet absorber, a resin dispersing the ultraviolet absorber, etc., and a resin forming a hard coat layer to form a coating film, and the coating film may be dried And hardening to form a single layer having the function of showing high hardness on the surface and ultraviolet absorption function, and coating the single layer with a solution containing a resin forming a hard coat layer to form a coating film by drying the coating film And hardened to form a hard coating. Using this method, it is possible to form a multi-layered functional layer including a layer having a function to show high hardness on the surface and a layer having a function to absorb ultraviolet rays and a layer having a function to show high hardness on the surface.

The laminate 30 of the present embodiment obtained in this way has excellent flexibility. The laminate 30 can have functions such as transparency, ultraviolet resistance, and the function of exhibiting high hardness on the surface, which are required when applied to the optical member of the flexible device or the base material of the display member, or the front panel, and the function of showing high hardness on the surface . When the laminate 30 has a Si/N of 8 or more on the main surface 10a of the resin film 10, the adhesion between the resin film 10 and the functional layer 20 is also excellent.

Fig. 3 is a cross-sectional view showing an embodiment of the laminate. The laminate 30 shown in FIG. 3 has an undercoat layer 25 provided between the resin film 10 and the functional layer 20 in addition to the resin film 10 and the functional layer 20 similar to the laminate in FIG. 2. The undercoat layer 25 is laminated on one main surface 10 a of the resin film 10. The functional layer 20 is layered on The main surface of the undercoat layer 25 in contact with the resin film 10 is the main surface 25a on the opposite side.

The undercoat layer 25 is a layer made of a primer, and it is preferable to contain a material that can improve the adhesion with the resin film 10 and the functional layer 20. The compound contained in the undercoat layer 25 may be chemically bonded at the interface with the polyimide-based polymer or silicon material contained in the resin film 10.

Examples of the primer agent include an ultraviolet curing type, thermosetting type, or two-component curing type epoxy compound primer. The primer can also be polyamide. These primers are suitable because they can improve the adhesion to the resin film 10 and the functional layer 20.

The primer may also contain a silane coupling agent. The silane coupling agent can also be chemically bonded to the silicon material contained in the resin film 10 through a condensation reaction. In particular, the silane coupling agent can be used when the compounding ratio of the silicon material contained in the resin film 10 is high.

Examples of the silane coupling agent include compounds having an alkoxysilyl group. The alkoxysilyl group has a silicon atom and 1 to 3 alkoxy groups covalently bonded to the silicon atom. A compound having a structure containing two or more alkoxy groups covalently bonded to silicon atoms is preferable, and a compound containing a structure containing three or more alkoxy groups covalently bonded to silicon atoms is preferable. Examples of the alkoxy group include methoxy, ethoxy, isopropoxy, n-butoxy, and third butoxy. Especially because it can improve the reactivity with silicon materials, methoxy and ethoxy are preferred.

The silane coupling agent preferably has a substituent having a high affinity with the resin film 10 and the functional layer 20. From and contained in the resin film 10 In view of the affinity of some polyimide-based polymers, the substituent of the silane coupling agent is preferably an epoxy group, an amine group, a urea group or an isocyanate group. When the functional layer 20 contains (meth)acrylates, the silane coupling agent used in the undercoat layer 25 has an epoxy group, a methacryloyl group, an acryloyl group, an amine group, or benzene because the affinity is improved. Vinyl is preferred. Among these, the silane coupling agent having a substituent selected from methacryloyl, acryloyl, and amine groups tends to have excellent affinity with the resin film 10 and the functional layer 20, which is good.

The thickness of the undercoat layer 25 can be adjusted appropriately according to the functional layer 20, and is preferably 0.01 nm to 20 μm. When an epoxy-based compound primer is used, the thickness of the primer layer 25 is preferably 0.01 μm to 20 μm, and more preferably 0.1 μm to 10 μm. When a silane coupling agent is used, the thickness of the undercoat layer 25 is preferably 0.1 nm to 1 μm, preferably 0.5 nm to 0.1 μm.

The laminate 30 in FIG. 3 can be formed, for example, by applying a solution containing a primer dissolved on the main surface 10a of the resin film 10, and drying and hardening the formed coating film to form an undercoat layer. Method to manufacture. The method of forming other members is the same as that of the laminate 30 in FIG. 2. The undercoat layer 25 and the functional layer 20 may be hardened at the same time, or they may be additionally hardened before the functional layer 20 is formed.

The resin film and the laminated system of the present embodiment have high transparency and can maintain excellent visibility during bending. In addition, the resin film and the laminate also have excellent flexibility. When an undercoat layer is provided between the resin film and the functional layer, the adhesion between the resin film and the functional layer becomes high. When the resin film and the lamination system are applied to the optical member of the flexible device, the base material of the display member, or the front panel, they can have the required transparency, ultraviolet resistance, and the function of making the surface have high hardness. Functionality.

The structure of the resin film and the laminate can be appropriately deformed. For example, functional layers can be provided on both sides of the resin film. At this time, an undercoat layer may be provided between the respective functional layers and the resin film.

[Display device (flexible device)]

Fig. 4 is a cross-sectional view showing an embodiment of a display device. The display device 100 shown in FIG. 4 includes an organic EL device 50, a touch sensor 70, and a front panel 90. These systems are usually housed in housings. Between the organic EL device 50 and the touch sensor 70, and between the touch sensor 70 and the front panel 90, for example, an optical clear adhesive (not shown) is used for bonding.

The organic EL device 50 is a display member provided with an organic EL element 51, a first substrate 55, a second substrate 56, and a sealing material 59.

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

The first electrode 52 is formed using a light-transmitting conductive material. The second electrode 53 may have light transmissivity. As the first electrode 52 and the second electrode 53, conventional materials can be used.

The light-emitting layer 54 can be used as a conventional organic EL device Luminescent material to form. The light-emitting material may be either a low-molecular compound or a high-molecular compound.

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

The first substrate 55 is formed of a material having light transmittance. The second substrate 56 may have light transmissivity. The first substrate 55 and the second substrate 56 are bonded together by a sealing material 59 arranged to surround the organic EL element. 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 are mostly gas barrier materials.

As a forming material for either or both of the first substrate 55 and the second substrate 56, an inorganic material such as glass or a conventional transparent resin such as acrylic resin can be used. As these members, the resin film or the laminate of the present embodiment described above can also be used.

The first substrate 55 and the second substrate 56 of the laminate of this embodiment can be used as the base material or gas barrier material of the display member of this embodiment. The organic EL device 50 having such a first substrate 55 and a second substrate 56 uses the resin film or laminate of this embodiment, and therefore has excellent flexibility.

The touch sensor 70 is an optical member having a touch sensor substrate 71 and an element layer 72, wherein the element layer 72 has a detection element formed on the touch sensor substrate 71.

The touch sensor substrate 71 is formed using a material having light transmittance. As the touch sensor substrate 71, an inorganic material such as glass or a conventional transparent resin such as acrylic resin can be used. As the touch sensor substrate 71, the above-mentioned resin film or laminate can also be used.

The element layer 72 is formed with a conventional detection element composed of semiconductor elements, wiring, resistors, and the like. As the configuration of the detection element, a configuration that realizes a conventional detection method such as a matrix switch, a resistive film method, or a capacitive method can be adopted.

The touch sensor substrate 71 that can employ the laminate of this embodiment corresponds to the optical member of this embodiment. The touch sensor 70 having such a touch sensor substrate 71 uses the resin film or laminate of this embodiment, and therefore has excellent flexibility.

The front panel 90 is formed of a material having light transmission. The front panel 90 is the outermost layer on the display screen side of the display device, and functions as a protection member for protecting the display device. The front panel is also called window film. As the front panel 90, an inorganic material such as glass or a conventional transparent resin such as acrylic resin can be used. As the front panel 90, the above-mentioned resin film or laminate can also be used. When a laminate is used as the front panel 90, generally, the functional layer is arranged in a direction located outside the display device.

The resin film or laminate front panel 90 of this embodiment can be used. Since the resin film or laminate of this embodiment is used, it has excellent flexibility.

When the display device 100 adopts the resin film or laminate of the present embodiment as one or more types of constituent members selected from the organic EL device 50, the touch sensor 70, and the front panel 90, the whole can have excellent flexibility. That is, the display device 100 can be a flexible device.

The device (flexible device) to which the resin film and the laminate of this embodiment can be applied is not limited to the above-mentioned display device. For example, a solar cell having a substrate on which a photoelectric conversion element is formed and a front panel provided on the surface of the substrate can also be used. In this case, when the resin film or laminate of this embodiment is used as the substrate or front panel of the solar cell, the entire solar cell can have excellent flexibility.

[Example]

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

[Example 1]

In the polymerization tank after nitrogen substitution, add the compound represented by formula (1), the compound represented by formula (2), the compound represented by formula (3), catalyst and solvent (γ butyrolactone and dimethylacetamide) . The addition amount is set to 75.0 g of the compound represented by formula (1), 36.5 g of the compound represented by formula (2), 76.4 g of the compound represented by formula (3), 1.5 g of catalyst, 438.4 g of γ-butyrolactone, and dimethyl 313.1g of acetamide. The molar ratio of the compound represented by formula (2) to the compound represented by formula (3) is 3:7, the total of the compound represented by formula (2) and the compound represented by formula (3) and the compound represented by formula (1) The molar ratio is 1.00: 1.02.

After stirring the mixture in the polymerization tank to dissolve the raw materials in the solvent, the mixture was heated up to 100°C, and then heated up to 200°C and held for 4 hours to polymerize to form polyimide. During this heating, the water in the liquid is removed. Subsequently, polyimide is obtained by purification and drying.

系紫外線吸收劑(TINUVIN(註冊商標)479、BASF公司製)、及水混合且攪拌30分鐘。該等攪拌係依據美國專利號碼US8,207,256B2所記載的方法進行。 Next, a γ-butyrolactone solution adjusted to a polyimide concentration of 20% by mass, a dispersion liquid obtained by dispersing silica particles with a solid content concentration of 30% by mass in γ-butyrolactone, and an alkane having an amino group Dimethyl acetamide solution of oxysilane, three

The ultraviolet absorber (TINUVIN (registered trademark) 479, manufactured by BASF) and water were mixed and stirred for 30 minutes. Such stirring is performed according to the method described in US Patent No. US 8,207,256 B2.

系紫外線吸收劑量設為3質量份，將相對於氧化矽粒子及聚醯亞胺的合計100質量份，水量設為10質量份。 Here, the mass ratio of the silicon oxide particles to the polyimide is set to 60:40; the amount of alkoxysilane having an amine group is 1.67 with respect to the total of 100 parts by mass of the silicon oxide particles and the polyimide. Parts by mass; 100 parts by mass relative to the total of silica particles and polyimide, three

The ultraviolet-ray absorbed dose was 3 parts by mass, and the amount of water was 10 parts by mass relative to 100 parts by mass of the total of silicon oxide particles and polyimide.

Apply the mixed solution to the glass substrate and heat at 50°C for 30 Minutes, heating at 140°C for 10 minutes and drying. Subsequently, by peeling the film from the glass substrate, mounting a metal frame and heating at 210° C. for 1 hour, a resin film with a thickness of 80 μm was obtained. The content of silicon oxide particles in the resin film is 60% by mass.

[Example 2 (Laminate)]

On one surface of the resin film produced in Example 1, a two-liquid curing type primer (trade name: ARACOAT AP2510, manufactured by Arakawa Chemical Industries, Ltd.) was applied to form a coating film as an undercoat layer, and the coating film was dried and cured An undercoat layer with a thickness of 1 μm was formed.

系紫外線吸收劑(TINUVIN(註冊商標)479、BASF公司製)3質量份、光聚合起始劑(IRGACURE(註冊商標)184、CIBA．SPECIALTY．CHEMICALS公司製)8質量份、調平劑(商品名：BYK-350、BYK-Chemie Japan公司製)0.6質量份、及甲基乙基酮107質量份混合而調製的溶液，塗布在底塗層上而形成塗膜。使該塗膜乾燥及硬化而形成厚度10μm之作為「具有使表面顯現高硬度的機能及具有紫外線吸收機能之機能層」的機能層，來得到實施例2的積層體。 Next, 47.5 parts by mass of 4-functional acrylate (trade name: A-TMMT, manufactured by Shin Nakamura Chemical Company), 47.5 parts by mass of 3-functional acrylate (trade name: A-TMPT, manufactured by Shin Nakamura Chemical Company), and reactive amine Formate polymer (trade name: 8BR-600, manufactured by Dacheng Fine Chemical Co., Ltd., 40% by mass) 12.5 parts by mass, three

3 parts by mass of ultraviolet absorber (TINUVIN (registered trademark) 479, manufactured by BASF), 8 parts by mass of photopolymerization initiator (IRGACURE (registered trademark) 184, manufactured by CIBA. SPECIALTY. CHEMICALS), leveling agent (commodity Name: BYK-350, manufactured by BYK-Chemie Japan Co., Ltd.) A solution prepared by mixing 0.6 parts by mass and 107 parts by mass of methyl ethyl ketone is coated on the undercoat layer to form a coating film. This coating film was dried and hardened to form a functional layer having a thickness of 10 μm as a “functional layer having a function to show high hardness on the surface and a functional layer having an ultraviolet absorbing function” to obtain a laminate of Example 2.

[Comparative Example 1]

系紫外線吸收劑以外，係與實施例1同樣地進行而得到厚度80μm的樹脂薄膜。 In addition to adding three in the mixed solution used to form the resin film

Except for the ultraviolet absorber, a resin film having a thickness of 80 μm was obtained in the same manner as in Example 1.

[Comparative Example 2]

Polyimide ("Neopulim" manufactured by Mitsubishi Gas Chemical Co., Ltd.) having a glass transition temperature of 390°C was prepared. A dispersion of γ-butyrolactone solution containing 20% by mass of polyimide, 30% by mass of solid oxide silica particles dispersed in γ-butyrolactone, and an alkoxysilane having an amine group The dimethylacetamide solution and water were mixed and stirred for 30 minutes to obtain a mixed solution. The mass ratio of silicon oxide particles to polyimide is 55:45 and is 100 parts by mass relative to the total amount of silicon oxide particles and polyimide. The amount of alkoxysilane having an amine group is 1.67 parts by mass and is relative to oxidation The total amount of silicon particles and polyimide is 100 parts by mass, and the amount of water is 10 parts by mass. Using this mixed solution and in the same manner as in Example 1, a resin film having a thickness of 80 μm was obtained.

(Evaluation) 1) Optical characteristics (yellowness (YI value))

The yellowness (Yellow Index: YI value) of each of the resin films of Examples and Comparative Examples was measured using an ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by Japan Spectroscopy Corporation. After measuring the background without a sample, the resin film is attached to the sample holder to measure For the transmittance of light from 300nm to 800nm, 3 stimulus values (X, Y, Z) are obtained. The YI value is calculated based on the following formula.

YI=100×(1.2769X-1.0592Z)/Y

2) Transmittance

The ultraviolet-visible-near-infrared spectrophotometer V-670 manufactured by Japan Spectroscopy Co., Ltd. was used to measure the transmittance of light from 300 nm to 800 nm to calculate the transmittance of light of 550 nm wavelength.

3) Haze

Using the fully automatic direct-reading haze computer HGM-2DP manufactured by SUGA Testing Machine Co., Ltd., the resin films of Examples and Comparative Examples were mounted on a sample holder, and the haze of the resin film was measured.

4) Light irradiation test

The resin films of the examples and comparative examples were subjected to a light irradiation test using UVCON manufactured by Atras Corporation. The light source is set to UV-B 313nm, the output power is set to 40W, and the distance between the resin film and the light source is set to 5cm.

The resin film was irradiated with ultraviolet rays for 24 hours. After ultraviolet irradiation, the optical characteristics (YI value, transmittance) as described above were evaluated.

5) Visibility

Bend the film before the light irradiation test to confirm the contrast and hue at this time The visual appearance is determined based on the following criteria.

A: No change in contrast and hue can be observed.

C: Changes in appearance such as contrast and changes in hue can be observed.

The evaluation results are shown in Table 1. The resin film of the example provided with the light irradiation test satisfies the above conditions (i) and (ii), and it can be confirmed that the resin film and the laminate system having the resin film have high visibility when bent.

10‧‧‧Resin film

10a, 10b‧‧‧Main

Claims (8)

A flexible device front panel is a flexible device front panel having a resin film of a polyimide-based polymer, wherein the polyimide-based polymer is a repeating structural unit represented by at least formula (PI) The polymer has a repeating structural unit represented by the aforementioned formula (PI) of 40 mole% or more relative to the total repeating structural units of the polyimide-based polymer;

In formula (PI), G represents a base selected from formula (20), formula (21), formula (22), formula (23), formula (24), formula (25) and formula (26) respectively At least one group that forms a group, * in formula (20) to formula (26) represents a dangling bond, and Z in formula (26) represents 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-, Ar is a C-based 6 to 20 aryl groups, at least one of the hydrogen atoms of these groups may be substituted by a fluorine-based substituent;

A represents any group selected from the group consisting of the groups represented by the following formula (30), formula (31), formula (32), formula (33) and formula (34); formula (30) to formula ( 34) * represents a dangling bond; in formulas (30), (31), (32) and (33), Z ¹ and Z ² are each independent and represent a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO- or -CO-NR-, wherein R is an alkyl group having 1 to 3 carbon atoms or a hydrogen atom, and the aforementioned formula (30) and formula (31), the groups represented by formula (32) and formula (33) may be introduced with a fluorine-based substituent; in formula (34), Z ¹ and Z ³ each independently represent a single bond, -O-, -CH ₂ -, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO- or -CO-NR-, wherein R is an alkyl group having 1 to 3 carbon atoms or a hydrogen atom, and Z ² represents a single bond, -CH ₂ -, -C(CH ₃ ) ₂ -, -SO ₂ -, -CO-, or -CO-NR-, wherein R is an alkyl group having 1 to 3 carbon atoms or a hydrogen atom;

With a light source installed at a distance of 5 cm from the resin film and having an output power of 40 W, the resin film was irradiated with 313 nm light from one side of the resin film for 24 hours, and the resin film satisfies the following conditions , (I) the resin film after the light irradiation test has a transmittance of 85% or more to light at 550 nm; and (ii) the resin 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 resin film was less than 2.5. The front panel of the flexible device as described in item 1 of the patent application scope, wherein the resin film after the light irradiation test has a haze of 1.0% or less. The front panel of a flexible device as described in item 1 of the patent application range, wherein the resin film further contains an ultraviolet absorber. The front panel of the flexible device as described in item 2 of the patent application scope, wherein the resin film further contains an ultraviolet absorber. The front panel of a flexible device according to any one of claims 1 to 4, wherein the front panel has the aforementioned resin film and a functional layer provided on at least one side of the resin film. The front panel of a flexible device as described in item 5 of the patent application range, wherein the functional layer is a layer having at least one function selected from the group consisting of ultraviolet absorption, adhesion, and functions that exhibit high hardness on the surface . The front panel of a flexible device as described in item 5 of the patent application range, wherein the front panel further has an undercoat layer disposed between the resin film and the functional layer. The front panel of a flexible device as described in item 6 of the patent application range, wherein the front panel further has an undercoat layer disposed between the resin film and the functional layer.

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