WO2023176411A1

WO2023176411A1 - Single-walled carbon nanotube dispersion liquid, curable resin composition, cured product and antistatic film

Info

Publication number: WO2023176411A1
Application number: PCT/JP2023/007155
Authority: WO
Inventors: 芽衣末岡; 亮介伊藤; 安史近田
Original assignee: 株式会社大阪ソーダ
Priority date: 2022-03-18
Filing date: 2023-02-27
Publication date: 2023-09-21

Abstract

The present invention provides a novel single-walled carbon nanotube dispersion liquid which exhibits good dispersibility of carbon nanotubes if mixed with a curable resin, and is capable of imparting good antistatic properties and excellent transparency to a curable resin composition.　The present invention provides a single-walled carbon nanotube dispersion liquid which contains single-walled carbon nanotubes, a conductive polymer that contains a repeating unit represented by formula (1), and a solvent. (In formula (1), a group R1 represents a linear or branched alkylene group having 3 to 5 carbon atoms; and a group R2 represents a hydrogen atom, a linear or branched alkyl group or a salt formed with a group -O-R2.)

Description

Single-walled carbon nanotube dispersion, curable resin composition, cured product, and antistatic film

The present invention relates to a single-walled carbon nanotube dispersion, a curable resin composition, a cured product, and an antistatic film.

Carbon nanotubes are used in various applications such as conductive fillers, thermally conductive materials, light emitting elements, electrode materials, electrode bonding materials, reinforcing materials, and black pigments.

Carbon nanotubes are minute structures with a diameter of nanometers, and because they are not easy to handle or process when used alone, they are produced as a carbon nanotube dispersion in a liquid medium and used for various purposes. It is common that

However, due to their high crystallinity, carbon nanotubes tend to aggregate in resins, and when a carbon nanotube dispersion is mixed with a resin and used for various purposes, the carbon nanotubes aggregate in the resin, causing problems with its properties. The problem is that they cannot fully demonstrate their abilities.

JP2019-189857A Patent No. 4635103

For example, carbon nanotubes are sometimes used in antistatic films for smartphones and the like for the purpose of imparting antistatic properties to the film. When using carbon nanotubes in an antistatic film, a pre-prepared carbon nanotube dispersion is mixed with a resin (transparent resin), and the resulting resin composition is applied onto a transparent substrate in the form of a film. Antistatic films can be produced.

In addition to antistatic properties, such antistatic films are required to have high transparency.

However, as mentioned above, carbon nanotubes are extremely prone to agglomeration, and even when carbon nanotubes are uniformly dispersed in a carbon nanotube dispersion, when the dispersion is mixed with a resin, the problem arises that the carbon nanotubes agglomerate in the resin. (For example, see Patent Document 1). When carbon nanotubes aggregate in a transparent resin, transparency decreases.

Furthermore, as another means for suppressing agglomeration of carbon nanotubes in a resin, there is also known a means of using a dispersant for carbon nanotubes. For example, butyral resin is known as a dispersant that improves the dispersibility of carbon nanotubes in resin (for example, Patent Document 2). However, because of its insulating properties, butyral resin inhibits the conductivity of carbon nanotubes. For this reason, there is a problem in that it is difficult to use insulating dispersants in applications that require electrical conductivity, such as antistatic films.

Under these circumstances, the present invention has good dispersibility of carbon nanotubes when mixed with a curable resin, and can impart good antistatic properties and excellent transparency to the curable resin composition. , the main objective is to provide a novel single-walled carbon nanotube dispersion. Another object of the present invention is to provide a curable resin composition using the single-walled carbon nanotube dispersion, a cured product of the curable resin composition, and an antistatic film using the cured product. do.

The present inventors conducted extensive studies to solve the above problems. As a result, a single-walled carbon nanotube dispersion containing single-walled carbon nanotubes, a conductive polymer containing a specific repeating unit, and a liquid medium is a dispersion of carbon nanotubes when mixed with a curable resin. It has been found that the antistatic properties and excellent transparency can be imparted to the curable resin composition.

The present invention was completed through further studies based on the above findings.

That is, the present invention can be described as follows.
Item 1. A single-walled carbon nanotube dispersion liquid comprising a single-walled carbon nanotube, a conductive polymer containing a repeating unit represented by the following formula (1), and a liquid medium.
[In the above formula (1), the group R ¹ is a linear or branched alkylene group having 3 to 5 carbon atoms, and the group R ² is a hydrogen atom, a linear or branched alkyl group, or a group - OR ² forms a salt. ]
Item 2. Item 2. The single-walled carbon nanotube dispersion according to item 1, wherein the liquid medium contains at least one of water and an organic solvent.
Item 3. Item 3. The single-walled carbon nanotube dispersion according to item 1 or 2, wherein the single-walled carbon nanotubes have a sedimentation rate of 60%/h or less, as measured by a light transmission centrifugal sedimentation method under the following conditions.
(Measurement conditions for sedimentation rate)
100 parts by mass of urethane acrylate and 3 parts by mass of 1-hydroxycyclohexyl-phenyl ketone are mixed with isopropyl alcohol to prepare a resin solution having a solid concentration of urethane acrylate of 30% by mass. The resin solution and the single-walled carbon nanotube dispersion are mixed to prepare a measurement sample containing 0.015% by mass of single-walled carbon nanotubes and 29% by mass of urethane acrylate based on the solid content of urethane acrylate. The sedimentation rate of the single-walled carbon nanotubes is calculated by filling 0.4 ml of the obtained measurement sample into a sample cell, rotating it at a high speed of 4000 rpm, and analyzing the particle separation phenomenon at the center of the cell based on the elapsed time.
Item 4. Item 1, wherein the mass ratio of the content of the conductive polymer to the content of the single-walled carbon nanotubes (content of the conductive polymer/content of the single-walled carbon nanotubes) is 1 or more and 10 or less. The single-walled carbon nanotube dispersion according to any one of items 1 to 3.
Item 5. A curable resin composition comprising a single-walled carbon nanotube, a conductive polymer containing a repeating unit represented by the following formula (1), a liquid medium, and a curable resin.
[In the above formula (1), the group R ¹ is a linear or branched alkylene group having 3 to 5 carbon atoms, and the group R ² is a hydrogen atom, a linear or branched alkyl group, or a group - OR ² forms a salt. ]
Item 6. Item 6. The curable resin composition according to item 5, wherein the liquid medium contains at least one of water and an organic solvent.
Section 7. Item 7. The curable resin composition according to item 5 or 6, wherein the single-walled carbon nanotubes have a sedimentation rate of 60%/h or less, as measured by a light transmission centrifugal sedimentation method under the following conditions.
(Measurement conditions for sedimentation rate)
The sedimentation rate of the single-walled carbon nanotubes is calculated by filling a sample cell with 0.4 ml of the curable resin composition, rotating it at a high speed of 4000 rpm, and analyzing the particle separation phenomenon at the center of the cell based on the elapsed time.
Section 8. Item 5, wherein the mass ratio of the content of the conductive polymer to the content of the single-walled carbon nanotubes (content of the conductive polymer/content of the single-walled carbon nanotubes) is 1 or more and 10 or less. The curable resin composition according to any one of items 1 to 7.
Item 9. The curable resin composition according to any one of Items 5 to 8, wherein the curable resin is urethane (meth)acrylate.
Item 10. A cured product of the curable resin composition according to any one of Items 5 to 9.
Item 11. Item 11. The cured product according to item 10, which is in the form of a film.
Item 12. The surface resistance value is 10 ¹¹ Ω/sq. Item 12. The cured product according to item 10 or 11, which is as follows.
Item 13. a transparent base material; an antistatic layer formed of the cured product according to any one of items 10 to 12, laminated on the transparent base material;
An antistatic film comprising:
Section 14. Item 14. The antistatic film according to item 13, which satisfies the following conditions.
(Total light transmittance of the antistatic film/Total light transmittance of the antistatic film when the antistatic layer is formed only with the curable resin)>0.94

According to the present invention, carbon nanotubes have good dispersibility when mixed with a curable resin, and can provide a curable resin composition with good antistatic properties and excellent transparency. A layered carbon nanotube dispersion can be provided. Further, according to the present invention, it is also possible to provide a curable resin composition using the single-walled carbon nanotube dispersion, a cured product of the curable resin composition, and an antistatic film.

1. Single-walled carbon nanotube dispersion The single- walled carbon nanotube dispersion of the present invention comprises single-walled carbon nanotubes and a conductive polymer (hereinafter referred to as conductive polymer A) containing a repeating unit represented by the following formula (1). ) and a liquid medium.

By having the above structure, the single-walled carbon nanotube dispersion liquid of the present invention has good dispersibility of carbon nanotubes when mixed with a curable resin, and has good antistatic properties for the curable resin composition. It can provide excellent transparency. Hereinafter, the single-walled carbon nanotube dispersion of the present invention will be described in detail.

In the single-walled carbon nanotube dispersion of the present invention (hereinafter sometimes referred to as the CNT dispersion of the present invention), the origin (manufacturing method) of the single-walled carbon nanotubes is not limited, and the effects of the present invention can be achieved. Single-walled carbon nanotubes may be manufactured by any method within the above range. Examples of methods for producing single-walled carbon nanotubes include arc discharge, laser evaporation, and chemical vapor deposition (CVD), with chemical vapor deposition (CVD) being preferred. The number of single-walled carbon nanotubes contained in the CNT dispersion of the present invention may be one, or two or more.

In the CNT dispersion of the present invention, the average particle diameter (D50) of the single-walled carbon nanotubes (single-walled CNTs) is not particularly limited as long as it achieves the effects of the present disclosure, but is preferably 4000 nm or less, more preferably It is 2000 nm or less, more preferably 600 nm or less. The average particle diameter (D50) of the single-walled carbon nanotubes is preferably 1 nm or more, more preferably 10 nm or more, and still more preferably 100 nm or more. The average particle diameter (D50) of single-walled carbon nanotubes was measured as follows.

<Measurement of average particle diameter (D50) of single-walled CNT>
The average particle diameter (D50) of the single-walled carbon nanotubes contained in the CNT dispersion of the present invention was measured using a dynamic light scattering particle size distribution analyzer (for example, manufactured by Otsuka Electronics, product name "ELSZ-2000ZS"). Measure the particle size distribution (scattering intensity standard) of CNTs. In the particle size distribution of single-walled CNTs, the particle size (nm) at which the cumulative volume calculated from the small diameter side is 50% is determined, and is defined as the scattering intensity average particle size D50.

In addition, from the viewpoint of achieving the effects of the present invention more preferably, in the CNT dispersion of the present invention, the single-walled carbon nanotubes have a G band and a D band in the Raman spectrum at an excitation wavelength of 532 nm measured by resonance Raman scattering method. The peak intensity ratio G/D is preferably 200 or less, more preferably 150 or less, even more preferably 100 or less, even more preferably 50 or less. The peak intensity ratio G/D is preferably 0.5 or more, more preferably 1 or more, still more preferably 2 or more. Note that "peak intensity ratio" means "height ratio".

In addition, from the viewpoint of exhibiting the effects of the present invention even more favorably, in the curable resin composition (resin solution) containing the CNT dispersion of the present invention, the The sedimentation rate of the layered carbon nanotubes is preferably 60%/h or less, more preferably 40%/h or less, still more preferably 35%/h or less, even more preferably 30%/h or less. The sedimentation rate is, for example, 0.001%/h or more, 0.01%/h or more, 0.1%/h or more.

(Measurement conditions for sedimentation rate)
100 parts by mass of urethane acrylate and 3 parts by mass of 1-hydroxycyclohexyl-phenyl ketone are mixed with isopropyl alcohol to prepare a resin solution having a solid concentration of urethane acrylate of 30% by mass. The resin solution and the single-walled carbon nanotube dispersion are mixed to prepare a measurement sample containing 0.015% by mass of single-walled carbon nanotubes and 29% by mass of urethane acrylate based on the solid content of urethane acrylate. The sedimentation rate of the single-walled carbon nanotubes is calculated by filling 0.4 ml of the obtained measurement sample into a sample cell, rotating it at a high speed of 4000 rpm, and analyzing the particle separation phenomenon at the center of the cell based on the elapsed time. As the urethane acrylate, a UV curable resin for coating is used, specifically, a product name: Beamset 575 manufactured by Arakawa Chemical Industry Co., Ltd. (70% by mass of urethane oligomer, 30% by mass of trimethyloltopropane triacrylate, number of functional groups) 3 to 6, solid content 100%, viscosity at 25° C. 12000±200 mPa·s, oligomer weight average molecular weight 1500 to 1600, monomer molecular weight approximately 300). If Beam Set 575 is not available, use DIC Corporation's product name: Luxidia V-4025 (UV curable resin for coating (urethane acrylate), number of functional groups: 6, solid content 78-82% by mass (butyl acetate), The viscosity at 25° C. is 370 to 630 mPa·s and the weight average molecular weight is about 1000).

In the CNT dispersion of the present invention, the content of single-walled carbon nanotubes is not particularly limited as long as it does not impede the effects of the present invention, and from the viewpoint of achieving the effects of the present invention more preferably, the content rate of single-walled carbon nanotubes is preferably 0. 01 to 1% by weight, more preferably 0.05 to 0.5% by weight, even more preferably 0.1 to 0.5% by weight.

The CNT dispersion of the present invention contains conductive polymer A along with single-walled carbon nanotubes. As described above, the conductive polymer A includes a repeating unit represented by the following formula (1).

In formula (1), the group R ¹ is a straight or branched alkylene group having 3 to 5 carbon atoms. Further, the group R ² is a hydrogen atom, a linear or branched alkyl group, or the group -O--R ² forms a salt.

In formula (1), when the group R ² is a hydrogen atom (H), the repeating unit represented by formula (1) above is a sulfonic acid. Further, when the group R ² is a linear or branched alkyl group, the repeating unit represented by the above formula (1) is a sulfonic acid alkyl ester, and the number of carbon atoms in the alkyl group is preferably 3 to 3. It is 5. In addition, when the group -O-R ² forms a salt, the compound represented by the above formula (1) is a sulfonic acid salt, and specific examples include lithium salt, sodium salt, and potassium salt of sulfonic acid. Examples include.

In formula (1), R ¹ is preferably a branched alkylene group having 4 or 5 carbon atoms, particularly preferably a group -CH ₂ -CH ₂ -CH(CH ₃ )-, a group -CH ₂ - CH ₂ --CH(CH ₂ CH ₃ )- or the group --CH ₂ --CH ₂ --CH ₂ --CH(CH ₃ )- is preferred. That is, the repeating unit represented by formula (1) is preferably the following formula (11), formula (12), or formula (13).

In the above formulas (1), (11), (12) and (13), R ² is H, Na, a group -CH ₂ C(CH ₃ ) ₃ , a group -CH(CH ₃ ) (CH ₂ CH ₃ ), the group -CH(CH ₃ ) ₂ and the like are preferred.

Further, in the conductive polymer A, the linker (spacer) connecting the repeating units represented by the above formula (1) is not particularly limited as long as the effect of the present invention is achieved, and for example, the number of carbon atoms is 1 to 1. 3 alkylene groups are mentioned. Further, the repeating unit represented by the above formula (1) may be directly bonded without having a linker (spacer).

From the viewpoint of exhibiting the effects of the present invention even more favorably, the conductive polymer A containing the repeating unit represented by the above formula (1) is preferably a self-doped conductive polymer. A self-doping conductive polymer is a conductive polymer that has a substituent (sulfo group, sulfonate group, etc.) in the main chain of the polymer, either directly or via a spacer, that provides both water solubility and a doping effect. As a self-doped conductive polymer, Tosoh Corporation's product name "SELFTRON" (registered trademark) is known. "SELFTRON" (registered trademark) corresponds to conductive polymer A containing a repeating unit represented by the above formula (1).

The number of repeating units contained in the conductive polymer A may be only one type, or two or more types. Among the repeating units (100% by mass) contained in the conductive polymer A, the proportion of the repeating units represented by the above formula (1) is not particularly limited as long as the effects of the present invention are achieved, and for example, , 5% by mass or more, 30% by mass or more, 50% by mass or more, 70% by mass or more, 90% by mass or more. When the proportion of the repeating unit represented by the above formula (1) is large, the conductive polymer A tends to become a self-doped conductive polymer.

From the viewpoint of exhibiting the effects of the present invention even more suitably, the weight average molecular weight of the conductive polymer A is preferably about 1,000 to 1,000,000, more preferably about 1,500 to 750,000. , more preferably about 2,000 to 500,000. Specifically, the weight average molecular weight of the conductive polymer A is a value measured by gel filtration chromatography (GPC).

In addition, from the viewpoint of exhibiting the effects of the present invention even more favorably, the viscosity of a 1% by mass isopropanol solution of conductive polymer A (in a 20°C environment) is, for example, 1 mPa·s or more, preferably 1 to 200 mPa·s. degree, more preferably about 1 to 100 mPa·s, still more preferably about 1 to 50 mPa·s. The method for measuring the viscosity of conductive polymer A is as follows.

<Method of measuring viscosity>
The viscosity is measured using a rheometer under the conditions of 25° C. environment, shear rate of 1.0 s ⁻¹ and cone plate: C60/2.

In addition, from the viewpoint of exhibiting the effects of the present invention even more favorably, the conductivity of a 1% by mass isopropanol solution of conductive polymer A is preferably about 10 ⁵ to 10 ¹⁰ Ω/sq., more preferably about 10 Ω/sq. It is about ⁶ to 10 ⁹ Ω/sq., more preferably about 10 ⁷ to 10 ⁹ Ω/sq. Specifically, the conductivity of the conductive polymer A is determined by applying No. ．． This is a value measured according to the method of the example after coating by a bar coating method using a No. 12 bar coater and drying by air drying.

From the viewpoint of exhibiting the effects of the present invention even more favorably, in the single-walled carbon nanotube dispersion of the present invention, the mass ratio of the content of conductive polymer A to the content of single-walled carbon nanotubes (conductive polymer A (content of single-walled carbon nanotubes) is preferably about 1 to 20, more preferably about 1 to 15, and even more preferably about 1 to 10. Considering the heat resistance of the curable resin composition using the CNT dispersion of the present invention, the mass ratio of the content of conductive polymer A to the content of single-walled carbon nanotubes is preferably 10 or less.

In the CNT dispersion of the present invention, the content of conductive polymer A is not particularly limited as long as it does not impede the effects of the present invention, and from the viewpoint of more preferably achieving the effects of the present invention, the content of conductive polymer A is preferably 0. .01 to 20% by weight, more preferably 0.05 to 10% by weight, and still more preferably 0.1 to 5% by weight.

Furthermore, in addition to the single-walled carbon nanotubes and the conductive polymer A, the CNT dispersion of the present invention further contains a liquid medium. The type of liquid medium is not particularly limited as long as it does not impede the effects of the present invention, and may be either a polar solvent or a non-polar solvent, for example. Furthermore, the CNT dispersion of the present invention may contain only one type of liquid medium, or may contain two or more types. From the viewpoint of achieving the effects of the present invention more suitably, the liquid medium is preferably a polar solvent. Preferred liquid media include, for example, water and organic solvents (preferably alcohols such as ethanol and isopropyl alcohol, and polar organic solvents such as DMF, NMP, ethyl acetate, butyl acetate, and methyl ethyl ketone). Among these, isopropyl alcohol is particularly preferred.

The proportion of the liquid medium in the CNT dispersion of the present invention is preferably 79.00 to 99.98% by mass, more preferably 84.00 to 99.98% by mass, even more preferably 89.00 to 99.98% by mass. Mass % is mentioned.

In addition to the single-walled carbon nanotubes, the conductive polymer A, and the liquid medium, the CNT dispersion of the present invention further contains additives included in known carbon nanotube dispersions, if necessary. Good too. In the CNT dispersion of the present invention, the content of the additive is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less.

An acid can be further added to the CNT dispersion of the present invention, if necessary. The type of acid is not particularly limited as long as it does not impede the effects of the present invention, and it may be either an organic acid or an inorganic acid. Further, the CNT dispersion of the present invention may contain only one type of acid, or may contain two or more types of acids. From the viewpoint of achieving the effects of the present invention more preferably, the pKa of the acid is preferably 0 to 15, more preferably 1 to 13, and even more preferably 1.5 to 8. Preferred acids include, for example, alcohol (preferably trifluoroethanol, phenol, etc.), carboxylic acid (preferably acetic acid, benzoic acid, etc.), phosphonic acid (preferably hexylphosphonic acid, phenylphosphonic acid, etc.), phosphoric acid (preferably hexylphosphonic acid, phenylphosphonic acid, etc.), Preferred examples include dibenzyl phosphate and the like. The acid content is preferably adjusted by the pKa of the acid. For example, when using phosphonic acid, the concentration is 0.001mM to 10M, more preferably 0.01mM to 1M, and even more preferably 0.1mM to 500mM. By adding an acid, the dispersibility of carbon nanotubes when mixed with a curable resin can be improved, and furthermore, the conductivity of the curable resin composition can be increased due to the doping effect.

The method for producing the CNT dispersion of the present invention is not particularly limited, and can be produced by mixing single-walled carbon nanotubes, conductive polymer A, and a liquid medium.

The CNT dispersion of the present invention has good dispersibility of carbon nanotubes when mixed with a curable resin, and can impart good antistatic properties and excellent transparency to the curable resin composition. Therefore, the CNT dispersion of the present invention can be suitably used for manufacturing a curable resin composition, which will be described later, and for manufacturing an antistatic film using the curable resin composition.

2. Curable Resin Composition The curable resin composition of the present invention comprises a single-walled carbon nanotube, a conductive polymer A containing a repeating unit represented by the above formula (1), a liquid medium, and a curable resin. It is characterized by including. The curable resin composition of the present invention can be suitably produced by using the CNT dispersion of the present invention described above. That is, the curable resin composition of the present invention can be suitably produced by mixing the CNT dispersion of the present invention and the curable resin.

As mentioned above, the CNT dispersion of the present invention has good dispersibility of single-walled carbon nanotubes when mixed with a curable resin, and has good antistatic properties and excellent transparency for the curable resin composition. Can be given gender. Therefore, in the curable resin composition of the present invention produced using the CNT dispersion of the present invention, the single-walled carbon nanotubes are uniformly dispersed in the curable resin composition, and the composition has good antistatic properties. It can exhibit excellent transparency. Therefore, for example, by using a cured resin layer obtained by curing the curable resin composition of the present invention on a transparent substrate as an antistatic layer, an antistatic film can be suitably produced.

For details of the single-walled carbon nanotubes, the conductive polymer A containing the repeating unit represented by formula (1), and the liquid medium in the curable resin composition of the present invention, please refer to "1. This is as explained in the section "Layered Carbon Nanotube Dispersion".

In the curable resin composition of the present invention, the content of single-walled carbon nanotubes is not particularly limited as long as it does not impede the effects of the present invention, and is preferably Examples include 0.001 to 0.1% by mass, more preferably 0.005 to 0.05% by mass, and still more preferably 0.005 to 0.04% by mass.

Furthermore, in the curable resin composition of the present invention, the content of the conductive polymer A is not particularly limited as long as it does not impede the effects of the present invention, and from the viewpoint of more preferably achieving the effects of the present invention. , preferably 0.010 to 0.500% by mass, more preferably 0.015 to 0.200% by mass, and even more preferably 0.015 to 0.100% by mass.

From the viewpoint of exhibiting the effects of the present invention even more favorably, in the curable resin composition of the present invention, the mass ratio of the content of conductive polymer A to the content of single-walled carbon nanotubes (the mass ratio of the content of conductive polymer A to the content of single-walled carbon nanotubes) content/content of single-walled carbon nanotubes) is preferably about 1 to 20, more preferably about 1 to 15, and still more preferably about 1 to 10. By setting the mass ratio of the content of conductive polymer A to the content of single-walled carbon nanotubes to 10 or less, a curable resin composition with excellent heat resistance can be obtained.

The proportion of the liquid medium in the curable resin composition of the present invention is preferably 10 to 70% by mass, more preferably 20 to 60% by mass, and even more preferably 30 to 50% by mass.

The curable resin contained in the curable resin composition of the present invention is not particularly limited. Since the curable resin composition of the present invention preferably has excellent transparency, the curable resin is preferably transparent.

The type of curable resin can be appropriately selected depending on the application, and examples include ionizing radiation-curable resins and thermosetting resins.

The ionizing radiation curable resin is a resin that is crosslinked and cured by irradiation with ionizing radiation, and includes a mixture of at least one of prepolymers, oligomers, monomers, etc. as appropriate. Here, ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta that can polymerize or crosslink molecules, and ultraviolet rays (UV) or electron beams (EB) are usually used; It also includes electromagnetic waves such as rays and gamma rays, and charged particle beams such as alpha rays and ion beams. Specific examples of the ionizing radiation-curable resin include urethane (meth)acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, and the like. Among these, the curable resin is particularly preferably urethane (meth)acrylate because the curable resin composition of the present invention can exhibit good antistatic properties and excellent transparency when cured. Ionizing radiation curable resins can be used alone or in combination of two or more.

Specific examples of thermosetting resins include epoxy resins, polyurethane resins (including two-component curable polyurethanes), unsaturated polyester resins, aminoalkyd resins, phenolic resins, urea resins, diallyl phthalate resins, and melamine resins. , guanamine resin, melamine-urea cocondensation resin, silicone resin, polysiloxane resin and the like. These thermosetting resins can be used alone or in combination of two or more.

A crosslinking agent, a curing agent such as a polymerization initiator, and a polymerization accelerator can be added to the curable resin composition. For example, as a curing agent, an organic amine or the like can be added to an epoxy resin, and an isocyanate, an organic sulfonate, or the like can be added to an unsaturated polyester resin, a polyurethane resin, or the like. Peroxides such as methyl ethyl ketone peroxide and radical initiators such as azoisobutyl nitrile can be added to the unsaturated polyester resin.

The curable resin composition of the present invention has a sedimentation rate of single-walled carbon nanotubes measured by a light transmission centrifugal sedimentation method under the following conditions, preferably 60%/h or less, more preferably 40%/h or less, More preferably, it is 35%/h or less, and even more preferably 30%/h or less. The sedimentation rate is, for example, 0.001%/h or more, 0.01%/h or more, 0.1%/h or more.

(Measurement conditions for sedimentation rate)
The sedimentation rate of the single-walled carbon nanotubes is calculated by filling a sample cell with 0.4 ml of the curable resin composition, rotating it at a high speed of 4000 rpm, and analyzing the particle separation phenomenon at the center of the cell based on the elapsed time.

The curable resin composition of the present invention becomes a cured product by being cured by irradiation with ionizing radiation or heating.

The cured product of the curable resin composition of the present invention preferably has a surface resistance value of 10 ¹¹ Ω/sq. Below, more preferably 10 ¹⁰ Ω/sq. More preferably 10 ⁹ Ω/sq. The lower limit is, for example, 10 ⁵ Ω/sq. can be mentioned. The surface resistance value was measured as described in Examples.

For example, in the curable resin composition of the present invention, when the curable resin is an ultraviolet curable resin, a cured product can be obtained by drying the curable resin composition and irradiating it with ultraviolet rays. For example, when the curable resin composition of the present invention is applied onto a transparent substrate, dried, and then cured by ultraviolet irradiation, a cured resin layer (cured product in the form of a film) is formed. A transparent film in which a cured resin layer and a transparent base material are laminated is obtained. The cured resin layer of the transparent film has antistatic properties. Therefore, by using the cured resin layer as an antistatic layer, the transparent film can be suitably used as an antistatic film in which the antistatic layer is laminated on a transparent base material.

3. Antistatic Film The antistatic film of the present invention comprises a transparent base material and an antistatic layer formed of a cured product of the curable resin composition of the present invention, which is laminated on the transparent base material. It is characterized by Since the antistatic film of the present invention includes an antistatic layer using the curable resin composition of the present invention, it has both good antistatic properties and excellent transparency.

The antistatic film of the present invention preferably satisfies the following conditions.
(Total light transmittance of the antistatic film/Total light transmittance of the antistatic film when the antistatic layer is formed only with the curable resin)>0.94

The total light transmittance of the antistatic film was measured as described in Examples.

The total light transmittance per unit thickness (5 μm) of the antistatic film of the present invention is preferably 70% or more, more preferably 75% or more, and still more preferably 81% or more.

In the antistatic film of the present invention, the transparent base material is formed of, for example, a transparent resin. The transparent resin is not particularly limited as long as it can be used as a base material for antistatic films, and includes polyesters such as polyethylene terephthalate, acrylic resins, polycarbonates, polypropylene, polystyrene, polyimides, polyamides, polysulfones, polyethersulfones, Examples include polyvinyl chloride, polyvinyl alcohol, polymethyl methacrylate, phenol resin, epoxy resin, and ABS resin.

The transparent base material is transparent. The total light transmittance per unit thickness (100 μm) of the transparent base material is preferably 70% or more, more preferably 80% or more, and still more preferably 84% or more. Measurement of total light transmittance is performed according to the description in Examples.

The thickness of the transparent base material is, for example, about 10 to 500 μm, preferably about 20 to 300 μm, and more preferably about 30 to 200 μm.

Further, the antistatic layer is formed of a cured product of the curable resin composition of the present invention. Therefore, the surface resistance value of the antistatic layer is preferably 10 ¹¹ Ω/sq. Below, more preferably 10 ¹⁰ Ω/sq. More preferably 10 ⁹ Ω/sq. The lower limit is, for example, 10 ⁵ Ω/sq. can be mentioned. The surface resistance value was measured as described in Examples.

The thickness of the antistatic layer is, for example, about 1 to 20 μm, preferably about 2 to 10 μm, and more preferably about 3 to 6 μm.

The antistatic film of the present invention can be suitably applied to, for example, interface screens of electronic devices such as smartphones.

The present invention will be explained in more detail with reference to examples below, but the following examples do not limit the scope of the present invention in any way.

The measurement methods in Examples and Comparative Examples are as follows.

(Measurement of surface resistance value)
Under standard conditions (23°C, 50% RH), the surface of the antistatic layer side of the antistatic film was measured using a high resistance resistivity meter (Hirestar-UX MCP-HT800, manufactured by Nitto Seiko Analytech). The surface resistance value was measured by applying a constant voltage/leakage current measurement method by pressing a USR probe MCP-HTP14 with a load of 2 kg.

(Total light transmittance)
The total light transmittance of the antistatic film was measured using an ultraviolet/visible/near-infrared spectrophotometer (UV 3600i, manufactured by Shimadzu Corporation) in accordance with JIS K7361-1.

(Dispersion stability (sedimentation rate))
The dispersion stability (sedimentation rate) of the curable resin composition was evaluated by the following procedure. Dispersion stability was evaluated using a method called light transmission centrifugal sedimentation using a dispersibility evaluation/particle size distribution device LS-610 manufactured by LUM Japan, using the sedimentation rate of carbon nanotubes in a solution measured. Specifically, a sample cell containing 0.4 ml of the curable resin composition as a measurement sample was rotated at a high speed of 4000 rpm at 25°C, and the particle separation phenomenon at the center of the cell was analyzed based on the elapsed time. , the sedimentation rate of carbon nanotubes was calculated. The above measurement device is equipped with data analysis software, and by automatically analyzing the measurement data, the sedimentation rate can be calculated.

Details of the raw materials used in the Examples and Comparative Examples are as follows.

(carbon nanotube)
Single-walled CNT1: Single-walled carbon nanotube manufactured by Osaka Soda Co., Ltd. (product name: OStube) Outer diameter: 2.0-3.0 nm, carbon purity: 99.7%, GD ratio: 90
Single-walled CNT2: Single-walled carbon nanotube manufactured by Zeon Nano Technology Co., Ltd. (product name: ZEONANO SG101) Outer diameter: 4.0 nm, carbon purity: 99.2%, GD ratio: 8
Multi-walled CNT1: Multi-walled carbon nanotube manufactured by Nanocyl (product name: NC7000)
Outer diameter: 9.5 nm, carbon purity: 90%, GD ratio: 1

(dispersant)
Dispersant 1: SELFTRON (registered trademark) organic solvent grade (manufactured by Tosoh Corporation, viscosity 4-6 mPa·s (1% by mass solution @ 25°C)), surface resistance 5.1×10 ⁸ Ω/sq. (1% by mass solution). A conductive polymer (self-doped conductive material) containing a repeating unit represented by the above general formula (1).
Dispersant 2: S-LEC BL-10 (manufactured by Sekisui Chemical Co., Ltd.) A polymer dispersant containing no repeating unit represented by the above general formula (1).

(transparent base material)
Polyethylene terephthalate film: Lumirror (registered trademark) #100-S10 (manufactured by Toray Industries, Inc.)

(Curable resin solution (binder resin solution))
100 parts by mass of urethane acrylate (manufactured by Arakawa Chemical Industries, Ltd., trade name: Beam Set 575) as a curable resin (transparent), and 3 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name: Irgacure 184). A liquid curable resin solution (binder resin solution (solid content concentration: 30% by mass)) was prepared using 10% and isopropanol.

(Manufacture of CNT dispersion liquid 1)
In a cylindrical glass tube with a diameter of 20 mm, 0.2 parts by mass of "OStube" as single-walled CNT1, 0.2 parts by mass of "SELFTRON" as a dispersant (conductive polymer), and 100 parts by mass of isopropanol as a solvent. added. The mixture was treated for 10 minutes using an ultrasonic homogenizer (UX-300, manufactured by Mitsui Electric Seiki Co., Ltd.) to obtain CNT dispersion 1 with a carbon nanotube concentration of 0.2% by mass.

Based on the formulations shown in the upper row of Table 1, CNT dispersions 2 to 8 were prepared in the same manner as CNT dispersion 1.

(Measurement of sedimentation rate of curable resin composition containing CNT dispersion 1)
225 mg of the obtained CNT dispersion 1 and 10 g of the above-mentioned curable resin solution (binder resin solution) were mixed, and the carbon nanotubes were 0.015% by mass and the urethane acrylate was 29% by mass based on the solid content of the urethane acrylate. A sample for measurement was prepared. The sedimentation rate of the obtained measurement sample was measured by the method described above and was found to be 29.8%/h.

(Measurement of sedimentation rate of curable resin composition containing CNT dispersion 2 and CNT dispersions 4 to 8)
Based on the same formulation as CNT dispersion 1, each measurement sample including CNT dispersion 2 and CNT dispersions 4 to 8 was prepared, and the sedimentation rate of the obtained solution for sedimentation rate measurement was measured. It became the street at the bottom of 1.

(Measurement of sedimentation rate of curable resin composition containing CNT dispersion 3)
450 mg of the obtained CNT dispersion 3 and 10 g of the above-mentioned curable resin solution (binder resin solution) were mixed, and the carbon nanotubes were 0.015% by mass and the urethane acrylate was 29% by mass based on the solid content of the urethane acrylate. A sample for measurement was prepared. The sedimentation rate of the obtained measurement sample was measured by the method described above and was found to be 0.6%/h.

(Manufacture of curable resin composition 1)
<Example 1>
Curable resin composition 1 was produced by mixing 225 mg of the obtained CNT dispersion 1 and 10 g of the above-mentioned curable resin solution (binder resin solution). In the curable resin composition, the amount of carbon nanotubes was 0.015 parts by mass and the amount of SELFTRON was 0.015 parts by mass with respect to 100 parts by mass of urethane acrylate.

<Examples 2 to 6, Comparative Examples 1 to 5>
Curable resin compositions 2 to 11 were each produced in the same manner as curable composition 1 based on the formulations shown in the upper row of Table 2.

(Production of antistatic films 1 to 11)
No. 1 on one side of the transparent base material. Each of the curable resin compositions 1 to 11 obtained above was applied to each base material by the bar coating method using a bar coater No. 12, and after air drying, a UV irradiation machine (light source: metal halide, integrated The film was cured at a light intensity of 600 mJ/cm ² ) to obtain antistatic films 1 to 11 in which an antistatic layer with a thickness of 5 μm was laminated on one side of a transparent substrate. When the surface resistance of the antistatic film 1 was measured, it was found to be 10 ⁷ Ω/sq. The total light transmittance was 84.7%. Further, the total light transmittance of antistatic film 7 (ie, Comparative Example 1) when the antistatic layer was formed only from the curable resin (urethane acrylate) was 85.9%. From this, in the antistatic film 1 of Example 1, the total light transmittance (84.7%) of the antistatic film 1 of Example 1/the charge when the antistatic layer is formed only with a curable resin The total light transmittance (85.9%) of the protective film 7 was 0.99.
The surface resistivity values of antistatic films 2 to 11 and the total light transmittance of antistatic films 2 to 11 were measured, and the results are summarized in the lower part of Table 2.

Claims

A single-walled carbon nanotube dispersion liquid comprising a single-walled carbon nanotube, a conductive polymer containing a repeating unit represented by the following formula (1), and a liquid medium.
[In the above formula (1), the group R 1 is a linear or branched alkylene group having 3 to 5 carbon atoms, and the group R 2 is a hydrogen atom, a linear or branched alkyl group, or a group - OR 2 forms a salt. ]
The single-walled carbon nanotube dispersion liquid according to claim 1, wherein the liquid medium contains at least one of water and an organic solvent.
The single-walled carbon nanotube dispersion according to claim 1 or 2, wherein the single-walled carbon nanotubes have a sedimentation rate of 60%/h or less, as measured by a light transmission centrifugal sedimentation method under the following conditions.
(Measurement conditions for sedimentation rate)
100 parts by mass of urethane acrylate and 3 parts by mass of 1-hydroxycyclohexyl-phenyl ketone are mixed with isopropyl alcohol to prepare a resin solution having a solid concentration of urethane acrylate of 30% by mass. The resin solution and the single-walled carbon nanotube dispersion are mixed to prepare a measurement sample containing 0.015% by mass of single-walled carbon nanotubes and 29% by mass of urethane acrylate based on the solid content of urethane acrylate. The sedimentation rate of the single-walled carbon nanotubes is calculated by filling 0.4 ml of the obtained measurement sample into a sample cell, rotating it at a high speed of 4000 rpm, and analyzing the particle separation phenomenon at the center of the cell based on the elapsed time.
A mass ratio of the content of the conductive polymer to the content of the single-walled carbon nanotubes (content of the conductive polymer/content of the single-walled carbon nanotubes) is 1 or more and 10 or less. Single-walled carbon nanotube dispersion liquid according to 1 or 2.
A curable resin composition comprising a single-walled carbon nanotube, a conductive polymer containing a repeating unit represented by the following formula (1), a liquid medium, and a curable resin.
[In the above formula (1), the group R 1 is a linear or branched alkylene group having 3 to 5 carbon atoms, and the group R 2 is a hydrogen atom, a linear or branched alkyl group, or a group - OR 2 forms a salt. ]
The curable resin composition according to claim 5, wherein the liquid medium contains at least one of water and an organic solvent.
The curable resin composition according to claim 5 or 6, wherein the single-walled carbon nanotubes have a sedimentation rate of 60%/h or less, as measured by a light transmission centrifugal sedimentation method under the following conditions.
(Measurement conditions for sedimentation rate)
The sedimentation rate of the single-walled carbon nanotubes is calculated by filling a sample cell with 0.4 ml of the curable resin composition, rotating it at a high speed of 4000 rpm, and analyzing the particle separation phenomenon at the center of the cell based on the elapsed time.
A mass ratio of the content of the conductive polymer to the content of the single-walled carbon nanotubes (content of the conductive polymer/content of the single-walled carbon nanotubes) is 1 or more and 10 or less. 6. The curable resin composition according to 5 or 6.
The curable resin composition according to claim 5 or 6, wherein the curable resin is urethane (meth)acrylate.
A cured product of the curable resin composition according to claim 5 or 6.
The cured product according to claim 10, which is in the form of a film.
The surface resistance value is 10 11 Ω/sq. The cured product according to claim 10, which is as follows.
a transparent base material; an antistatic layer formed of the cured product according to claim 10, laminated on the transparent base material;
An antistatic film comprising:
The antistatic film according to claim 13, which satisfies the following conditions.
(Total light transmittance of the antistatic film/Total light transmittance of the antistatic film when the antistatic layer is formed only with the curable resin)>0.94