JP7265332B2 - touch panel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a writing feeling improving sheet capable of improving the writing feeling with a touch pen on a touch panel or the like.

2. Description of the Related Art In recent years, image display devices (touch panels) with a position detection function, which serve as display devices and input means, have been widely used in various electronic devices. In such a touch panel, there is a type in which input is performed using a touch pen as well as a type in which input is performed using a finger. The touch pen enables finer and more accurate input work than a finger. However, the display module of the touch panel is usually rigid. Therefore, the feeling of writing with a touch pen is different from the feeling of writing on paper with a pen such as a ballpoint pen or a fountain pen, and it is difficult to say that it is good.

In order to solve the problem of writing comfort with a touch pen on a touch panel, a film that improves writing comfort (hereinafter sometimes referred to as "writing comfort improving film" or "writing comfort improving sheet") is placed on the outermost surface of the touch panel. Affixing is being considered. As such a writing comfort improving film, for example, Patent Document 1 includes a transparent base film and linear protrusions forming a network structure on at least one surface of the transparent base film, and the network structure is regular. Disclosed is a tactile film having a plurality of sections arranged in a regular pattern, and linear protrusions occupying an area of 5 to 80% of the entire surface of the tactile film.

JP 2015-054417 A

However, in the invention disclosed in Patent Document 1, the pen tip feels stuck or slippery, and the sound and vibration during writing are different from when writing with the pen on paper. However, it was not possible to sufficiently obtain the feeling of writing when writing on. In addition, conventional films for improving the writing feel tend to be whitish, that is, so-called "discoloration" occurs, which may reduce the visibility of the displayed image or deteriorate the appearance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet for improving the writing feel that is excellent in writing feel with a touch pen and suppresses the occurrence of discoloration.

To achieve the above object, the present invention provides a base material, a writing quality improving layer provided on one side of the base material, and a writing quality improving layer provided on the side opposite to the base material in the writing quality improving layer. wherein the refractive index of the optical adjustment layer is less than the refractive index of the writing comfort improvement layer, and the surface of the writing comfort improvement sheet on the optical adjustment layer side , the pen tip of a hard felt core touch pen with a pen tip diameter of 0.5 mm is brought into contact in the vertical direction under a pressure condition of a load of 3.92 N, and is moved at a speed of 100 mm in any one direction parallel to the surface of the optical adjustment layer. The initial movement value (A) and the sliding value (B) of the pen tip resistance force (mN) when moving at /min satisfy the relationship of the following formulas (a) and (b) 0 < initial movement value (A ) - Sliding value (B) … (a)
350 ≤ initial value (A) … (b)
(Invention 1).

In the writing feeling improving sheet according to the above invention (invention 1), by having the above configuration and physical properties, the writing feeling with a touch pen is excellent, and the occurrence of discoloration caused by the writing feeling improving sheet is suppressed.

In the above invention (invention 1), the optical adjustment layer preferably has a refractive index of 1.2 or more and 1.5 or less (invention 2).

In the above inventions (inventions 1 and 2), the total haze of the writing comfort improving sheet is preferably 5% or more and 40% or less (invention 3).

In the above inventions (inventions 1 to 3), the optical adjustment layer is preferably a layer obtained by curing a coating composition containing a curable component and fine particles (invention 4).

In the above inventions (inventions 1 to 4), the writing feel improving layer is preferably a layer formed by curing a coating composition containing a curable component and fine particles (invention 5).

According to the writing comfort improving sheet of the present invention, the writing comfort with a touch pen is excellent, and the occurrence of discoloration is suppressed.

1 is a cross-sectional view of a writing comfort improving sheet according to an embodiment of the present invention; FIG. 4 is a graph showing an example of measurement results of pen tip resistance (an example relating to the writing comfort improvement sheet according to the present embodiment). FIG. 10 is a graph showing another example of pen tip resistance measurement results (an example relating to a general writing comfort improvement sheet). FIG.

Embodiments of the present invention will be described below.
The writing comfort improving sheet according to the present embodiment is a sheet that constitutes the outermost layer of a touch panel in which a touch pen is used. an optical adjustment layer provided on a side of the enhancement layer opposite the substrate. Preferably, as shown in FIG. 1, the writing feeling improving sheet 1 according to the present embodiment is formed by laminating a substrate 11, a writing feeling improving layer 12, and an optical adjustment layer 13 in that order.

In the writing feeling improving sheet 1 , the refractive index of the optical adjustment layer 13 is less than the refractive index of the writing feeling improving layer 12 . In addition, in the writing quality improving sheet 1, a load of 3.92 N was applied to the surface of the writing quality improving sheet 1 on the optical adjustment layer 13 side by applying a pen tip of a hard felt core touch pen with a pen tip diameter of 0.5 mm. Initial movement value (A) and sliding value of pen tip resistance (mN) when contact is made in the vertical direction under a pressure condition and moved at a speed of 100 mm/min in an arbitrary direction parallel to the surface of the optical adjustment layer 13 (B) satisfies the relationship of the following formulas (a) and (b) (hereinafter sometimes referred to as "writing taste property").
0 < initial value (A) - sliding value (B) (a)
350 ≤ initial value (A) … (b)

The writing quality improving sheet 1 having the above configuration and physical properties has excellent writing quality with a touch pen, and suppresses discoloration caused by the writing quality improving sheet 1 . Therefore, according to the writing feeling improving sheet 1 according to the present embodiment, it is possible to maintain good visibility and appearance of the displayed image while having excellent writing feeling.

In the writing feeling improving sheet 1 according to the present embodiment, the value (refractive index difference) obtained by subtracting the refractive index of the optical adjustment layer 13 from the refractive index of the writing feeling improving layer 12 is a value larger than 0, preferably 0.5. 01 or more, particularly preferably 0.05 or more, and more preferably 0.10 or more. By setting the refractive index difference to such a value, the occurrence of white discoloration in the writing quality improving sheet 1 is effectively suppressed. On the other hand, the upper limit of the refractive index difference is preferably 0.30 or less, particularly preferably 0.25 or less, and further preferably 0.20 or less. When the upper limit value of the refractive index difference is such a value, it becomes easy to suppress the occurrence of discoloration and the occurrence of glare in the writing quality improving sheet 1, and the visibility and appearance of the displayed image are improved. can be maintained.

The upper limit of the refractive index of the optical adjustment layer 13 is preferably 1.50 or less, particularly preferably 1.45 or less, and further preferably 1.40 or less. When the upper limit value of the refractive index of the optical adjustment layer 13 is above, the refractive index difference described above is easily satisfied. The lower limit of the refractive index of the optical adjustment layer 13 is preferably 1.20 or more, particularly preferably 1.25 or more, and further preferably 1.30 or more. When the lower limit value of the refractive index of the optical adjustment layer 13 is above, the upper limit value of the refractive index difference can be easily adjusted to a desired value.

The refractive index of the writing comfort improving layer 12 is preferably 1.40 or more, particularly preferably 1.45 or more, and further preferably 1.50 or more. The refractive index of the writing comfort improving layer 12 is preferably 1.70 or less, particularly preferably 1.60 or less, and further preferably 1.55 or less. When the refractive index of the writing feeling improving layer 12 is within the above range, excellent writing feeling can be achieved, and the refractive index difference described above can be easily satisfied.

In addition, the refractive index of each layer in this specification is the value measured by the method shown in the test example.

Here, the initial movement value (A) of the pen tip resistance is the value of the pen tip resistance shown at the stage when the touch pen starts scanning, and is usually detected as a peak value as shown in FIGS. . On the other hand, the sliding value (B) of the pen tip resistance means the average value of the pen tip resistance in a stable scanning state after the influence of the initial motion subsides. For example, in FIG. 2, the sliding value (B) is the average value of the pen tip resistance over a scanning length of 10 to 40 mm. On the other hand, in FIG. 3, the sliding value (B) is the average value of the pen tip resistance over the scanning length of 15 to 40 mm.

As shown in the above formula (a), when the value obtained by subtracting the sliding value (B) from the initial movement value (A) (difference in pen tip resistance (A - B)) becomes a value greater than 0 mN, the writing In the taste improving sheet 1, the writing feeling of the stylus is improved by the writing feeling improving sheet itself without providing an adhesive layer or the like having a cushioning property. It is considered that this is because the relationship between the initial movement value (A) and the sliding value (B) is close to the relationship when writing with a pencil on paper. From this point of view, the lower limit of the value obtained by subtracting the sliding value (B) from the initial value (A) is preferably 10 mN or more, particularly preferably 40 mN or more, and further preferably 70 mN or more. preferable. In addition, the initial value (A) indicating the peak top is not observed in a general hard coat film having no unevenness on the surface. In addition, as shown in FIG. 3, with a general writing comfort improvement sheet, although the initial movement value (A) is observed, the pen tip resistance increases after that, and the sliding value (B) increases. The pen tip resistance difference (AB) usually shows a negative value.

If the initial movement value (A) and the sliding value (B) satisfy the above relationship, when using a touch pen with a different material and tip diameter from the hard felt core touch pen (for example, a polyacetal core touch pen). However, the effect of improving the writing comfort of the writing comfort improving sheet is confirmed.

On the other hand, if the value obtained by subtracting the sliding value (B) from the initial movement value (A) is too large, the pen tip may be easily worn, and the pen tip may feel stuck at the beginning of writing or may cause noise. There is From this point of view, the upper limit of the value obtained by subtracting the sliding value (B) from the initial value (A) is preferably 300 mN or less, particularly preferably 250 mN or less, and further preferably 200 mN or less. preferable.

Furthermore, as shown in the above formula (b), when the initial movement value (A) is 350 mN or more, the writing feeling improving sheet 1 prevents the pen tip from slipping too much at the beginning of writing, and the writing feeling of the touch pen is good. become something. From this point of view, the initial value (A) is preferably 400 mN or more, particularly preferably 500 mN or more.

On the other hand, the initial value (A) is preferably 1000 mN or less. This is because the writing feel improvement sheet 1 suppresses the feeling that the pen tip is caught at the beginning of writing and the generation of noise, and the writing feel of the touch pen is improved. From this point of view, the upper limit of the initial value (A) is preferably 900 mN or less, particularly preferably 800 mN or less, and further preferably 750 mN or less.

The lower limit of the sliding value (B) is preferably 100 mN or more, particularly preferably 250 mN or more, further preferably 400 mN or more. The upper limit of the sliding value (B) is preferably 900 mN or less, particularly preferably 750 mN or less, further preferably 600 mN or less. If the sliding value (B) is within such a range, the writing quality improving sheet 1 can effectively suppress the occurrence of a feeling of catching or slipping on the pen tip during writing. The sound and vibration of the pen are likely to be similar to those of writing on paper with a pen, and the feeling of writing is further improved.

The lower limit of the total haze of the writing feeling improving sheet 1 is preferably 5% or more, particularly preferably 8% or more, and further preferably 16% or more. When the lower limit of the total haze is above, glare caused by the writing feeling improving sheet 1 is suppressed. The upper limit of the total haze of the writing comfort improving sheet 1 is preferably 40% or less, particularly preferably 30% or less, and further preferably 21% or less. When the upper limit of the total haze is above, the occurrence of discoloration caused by the writing quality improving sheet 1 is likely to be effectively suppressed, the light transmittance is secured, and the visibility of the displayed image is better. becomes.

The lower limit of the external haze of the writing comfort improving sheet 1 is preferably 5% or more, particularly preferably 8% or more, and further preferably 15% or more. When the lower limit of the external haze is above, glare caused by the writing quality improving sheet 1 is effectively suppressed. The upper limit of the external haze of the writing comfort improving sheet 1 is preferably 40% or less, particularly preferably 30% or less, and further preferably 22% or less. When the upper limit value of the external haze is above, the occurrence of discoloration caused by the writing quality improving sheet 1 can be effectively suppressed.

The total haze of the writing comfort improving sheet 1 in this embodiment is the total haze of the entire laminate of the substrate 11, the writing comfort improving layer 12, and the optical adjustment layer 13 (total of internal haze and external haze). Further, haze in this specification is a value measured according to JIS K7136:2000. Specific methods for measuring total haze and external haze are as shown in test examples described later.

1. Each member (1) Base material The base material 11 may be appropriately selected from those suitable for a touch panel in which a stylus is used. However, the base material 11 may be glass.

Examples of such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene film and polypropylene film, cellophane, diacetylcellulose film, triacetylcellulose film, acetylcellulose butyrate film, Polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, poly Etherimide film, fluororesin film, polyamide film, acrylic resin film, polyurethane resin film, norbornene polymer film, cyclic olefin polymer film, cyclic conjugated diene polymer film, vinyl alicyclic hydrocarbon polymer film, etc. plastic films or laminated films thereof. Among them, a polyethylene terephthalate film, a polycarbonate film, a norbornene-based polymer film, or the like is preferable, and a polyethylene terephthalate film is particularly preferable, because it can maintain a good writing feel with a touch pen in combination with the above-described writing feel improving layer 12 .

In addition, in order to improve adhesion with the layers provided on the surface of the base material 11 (optical adjustment layer 13, pressure-sensitive adhesive layer described later, etc.), one or both sides of the base material 11 may optionally be subjected to a primer treatment, an oxidation method, or the like. , surface treatment can be performed by a roughening method or the like. Examples of the oxidation method include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone/ultraviolet treatment, and the like. Examples of the roughening method include sandblasting and solvent treatment. These surface treatment methods are appropriately selected according to the type of substrate 11 . As an example, a plastic film, particularly a polyethylene terephthalate film, having an easy-adhesion layer formed by primer treatment is preferably used.

The thickness of the base material 11 is preferably 15-300 μm, particularly preferably 30-200 μm, further preferably 90-150 μm.

(2) Writing feeling improving layer (2-1) Writing feeling improving layer material The writing feeling improving layer 12 of the writing feeling improving sheet 1 in this embodiment is made of a material that satisfies the above-described refractive index difference and writing feeling physical properties. , may be formed from any material, but is preferably formed by curing a coating composition C1 described below. According to the coating composition C1, it is easy to form the writing feeling improving layer 12 that satisfies the above refractive index difference and writing feeling properties.

The coating composition C1 in this embodiment preferably contains a curable component and fine particles.

(2-1-1) Curable Component The curable component is a component that is cured by triggers such as active energy rays and heat, and examples thereof include active energy ray-curable components and thermosetting components. In this embodiment, it is preferable to use an active energy ray-curable component from the viewpoint of the hardness of the formed writing comfort improving layer 12, the heat resistance of the substrate 11 (plastic film), and the like.

As the active energy ray-curable component, it is preferable to use a component that can be cured by irradiation with an active energy ray to exhibit a predetermined hardness and that can achieve the physical properties described above in relation to the fine particles.

Specific active energy ray-curable components include polyfunctional (meth)acrylate monomers, (meth)acrylate prepolymers, active energy ray-curable polymers, etc. Among them, polyfunctional (meth)acrylates It is preferably a polyfunctional monomer and/or a (meth)acrylate prepolymer, more preferably a polyfunctional (meth)acrylate monomer. A polyfunctional (meth)acrylate-based monomer and a (meth)acrylate-based prepolymer may be used alone, or both may be used in combination. In this specification, (meth)acrylate means both acrylate and methacrylate. The same applies to other similar terms.

Examples of polyfunctional (meth)acrylate monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, (Meth)acrylates, neopentylglycol hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphate di(meth)acrylate, allylated Cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate ) acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate ) acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, and other polyfunctional (meth)acrylates. These may be used individually by 1 type, and may be used in combination of 2 or more type.

On the other hand, examples of (meth)acrylate prepolymers include polyester acrylate, epoxy acrylate, urethane acrylate, and polyol acrylate prepolymers.

As the polyester acrylate prepolymer, for example, by esterifying the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyhydric carboxylic acid and a polyhydric alcohol with (meth)acrylic acid, or by esterifying a polyhydric It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a carboxylic acid with (meth)acrylic acid.

An epoxy acrylate prepolymer can be obtained, for example, by reacting (meth)acrylic acid with an oxirane ring of a relatively low-molecular-weight bisphenol-type epoxy resin or novolak-type epoxy resin to esterify it.

A urethane acrylate prepolymer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate with (meth)acrylic acid.

A polyol acrylate prepolymer can be obtained, for example, by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid.

One of the above prepolymers may be used alone, or two or more may be used in combination.

It is also preferable to use an organic-inorganic hybrid resin as the active energy ray-curable component. As the organic-inorganic hybrid resin, a substance obtained by bonding an organic compound having a polymerizable unsaturated group to inorganic fine particles such as silica via a silane coupling agent or the like is preferably exemplified. The inorganic fine particles contained in the organic-inorganic hybrid resin, which corresponds to fine particles described later, have a function as an organosol and also a function as a binder. When the organic-inorganic hybrid resin is used, the above-described writing feel physical properties can be easily obtained due to its action as an organosol, and the surface hardness of the formed writing feeling improving layer 12 can be improved.

(2-1-2) Fine Particles Fine particles are preferably those capable of achieving the physical properties described above in relation to the curable component. The fine particles may be inorganic fine particles or organic fine particles, or inorganic fine particles and organic fine particles may be used in combination. Preferably, at least inorganic fine particles are used, and particularly preferably, inorganic fine particles and organic fine particles are used in combination. By using at least the inorganic fine particles, the above-mentioned writing taste properties are easily satisfied. In addition, by using inorganic fine particles and organic fine particles in combination, it becomes easier to satisfy the refractive index difference described above.

Examples of inorganic fine particles include fine particles made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like. Among these, silica fine particles are preferred. In addition, fine particles may be used singly or in combination of two or more.

The shape of the inorganic fine particles may be a regular shape such as a sphere, but an irregular shape whose shape is not specified is preferable. According to irregular-shaped fine particles, it is easier to satisfy the relationship between the initial resistance value (A) of the pen tip and the sliding value (B) than the spherical fine particles, and the writing feeling of the touch pen is improved. Become. Therefore, it is particularly preferable that the fine particles are amorphous silica fine particles.

Silica fine particles may be modified with an organic substance for the purpose of improving dispersibility. The silica fine particles are also preferably in the form of an organosol (colloidal form) (silica sol). The silica fine particles contained in the organic-inorganic hybrid resin described above are usually in the form of an organosol. By being in the form of an organosol, the dispersibility of the silica fine particles is improved, and the homogeneity and light transmittance of the formed writing quality improving layer 12 are improved.

Modification with an organic substance can be performed by a conventional method. For example, a silane coupling agent having a structure such as CH ₂ ═C(CH ₃ )COO(CH ₂ ) ₃ Si(OCH ₃ ) ₃ is added to the silica fine particle organosol, heated to about 50° C. and stirred for several hours. By doing so, the surface of the silica fine particles can be modified. The structure and amount of the silane coupling agent to be used are appropriately selected according to the required degree of dispersibility of the silica fine particles.

As the dispersing solvent for the above-mentioned organosol, methyl ethyl ketone, methyl isobutyl ketone, and the like, which are excellent in compatibility with polyfunctional (meth)acrylates and leveling agents and in volatility during coating layer formation, are preferred.

The average particle size of inorganic fine particles that are not organosols is preferably 0.5 μm or more, particularly preferably 1.0 μm or more, and further preferably 1.5 μm or more. The average particle diameter of inorganic fine particles that are not organosols is preferably 10 µm or less, particularly preferably 4 µm or less, and more preferably 2 µm or less. When the average particle diameter of the inorganic fine particles that are not organosols is within the above range, it becomes easier to satisfy the refractive index difference and the physical properties of the writing feel described above, and it is also possible to suppress glare. Furthermore, the surface hardness of the formed writing feeling improving layer 12 can be improved.

The average particle size of the inorganic fine particles as the organosol, particularly silica sol, is preferably 1 nm or more, particularly preferably 5 nm or more, and more preferably 10 nm or more. The average particle size of the inorganic fine particles as the organosol is preferably 300 nm or less, more preferably 100 nm or less, particularly preferably 80 nm or less, and further preferably 50 nm or less. When the average particle size of the inorganic fine particles as the organosol is within the above range, it becomes easier to satisfy the refractive index difference and the physical properties of the writing feel described above, and it is also possible to suppress glare. Furthermore, the surface hardness of the formed writing feeling improving layer 12 can be improved.

On the other hand, organic fine particles include, for example, silicone fine particles, melamine resin fine particles, acrylic resin fine particles (for example, polymethyl methacrylate resin fine particles), acrylic-styrene copolymer fine particles, polycarbonate fine particles, and polyethylene fine particles. , polystyrene-based fine particles, and benzoguanamine-based resin fine particles. These resins may be crosslinked. Among these, from the viewpoint of optical properties and hardness, acrylic resin fine particles are preferred, polymethyl methacrylate resin fine particles are particularly preferred, and crosslinked polymethyl methacrylate resin fine particles are more preferred.

The shape of the organic fine particles may be a fixed shape such as a sphere, or may be an amorphous shape whose shape is not specified, but is preferably spherical. By using spherical organic fine particles together with the inorganic fine particles described above, the feeling of writing with a touch pen is given a favorable sense of resistance and friction. and become better. In addition, the effect of suppressing glare becomes more excellent.

The average particle size of the organic fine particles is preferably 1.0 μm or more, particularly preferably 1.2 μm or more, and further preferably 1.5 μm or more. The average particle diameter of the organic fine particles is preferably 15 μm or less, more preferably 10 μm or less, particularly preferably 8 μm or less, and further preferably 5 μm or less. When the average particle size of the organic fine particles is within the above range, the above-described writing feel property is easily satisfied, and the writing feel of the touch pen becomes closer to the sensation of writing on paper with a pen.

It should be noted that the average particle diameter of fine particles in this specification is obtained by measuring the primary particle diameter by a laser diffraction method. The average particle size by the laser diffraction method was obtained by sufficiently stirring 1.2 g of fine particles and 98.8 g of isopropyl alcohol as a measurement sample, and using a laser diffraction scattering particle size distribution analyzer (manufactured by Horiba Ltd., product name "LA -920").

Regarding the particle size distribution of the fine particles, the coefficient of variation (CV value) of the particle size represented by the following formula should be 3% or more from the viewpoint of making it easier for the writing feeling improving layer 12 to obtain the aforementioned physical properties of writing feeling. It is preferably 5% or more, and more preferably 10% or more. Also, from the same viewpoint, the CV value is preferably 200% or less, more preferably 175% or less, particularly preferably 150% or less, and further preferably 30% or less. preferable.
Particle size variation coefficient (CV value) (%) = (standard deviation particle size / average particle size) x 100
The coefficient of variation (CV value) of the particle size is the value measured by a laser diffraction/scattering particle size distribution analyzer (manufactured by Horiba, Ltd., product name “LA-920”).

The content of the inorganic fine particles that are not organosols in the coating composition C1 is preferably 1% by mass or more, particularly preferably 3% by mass or more, and further preferably 5% by mass or more. Moreover, the content of the fine particles is preferably 40% by mass or less, particularly preferably 30% by mass or less, and further preferably 20% by mass or less. When the content of the non-organosol inorganic fine particles is within the above range, the above-described refractive index difference and writing feel properties can be easily obtained.

The content of inorganic fine particles as an organosol in the coating composition C1, particularly silica sol, is preferably 1% by mass or more, particularly preferably 3% by mass or more, and more preferably 5% by mass or more. is preferred. The content is preferably 40% by mass or less, particularly preferably 30% by mass or less, further preferably 20% by mass or less. When the content of the inorganic fine particles as the organosol is within the above range, the refractive index difference and the writing feel property described above can be easily obtained.

The content of the organic fine particles in the coating composition C1 is preferably 3% by mass or more, particularly preferably 7% by mass or more, and further preferably 10% by mass or more. The content of the organic fine particles is preferably 40% by mass or less, particularly preferably 30% by mass or less, and further preferably 15% by mass or less. When the content of the organic fine particles is within the above range, the aforementioned difference in refractive index and physical properties of writing feel can be easily obtained, and the effect of suppressing glare is more excellent. Furthermore, the surface hardness of the formed writing feeling improving layer 12 can be improved.

(2-1-3) Photopolymerization Initiator When ultraviolet rays are used as the active energy ray for curing the active energy ray-curable component, the coating composition C1 preferably contains a photopolymerization initiator. . By containing the photopolymerization initiator in this manner, the active energy ray-curable component can be efficiently polymerized, and the polymerization curing time and the amount of ultraviolet irradiation can be reduced.

Examples of such photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2- Phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio) Phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylaminobenzophenone, dichloro Benzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4- Diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6- and trimethylbenzoyl-diphenyl-phosphine oxide. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator in the coating composition C1 is preferably 0.01 parts by mass or more as a lower limit, particularly 0.1 parts by mass or more, relative to 100 parts by mass of the active energy ray-curable component. and more preferably 1 part by mass or more. Also, the upper limit is preferably 20 parts by mass or less, particularly preferably 10 parts by mass or less, and more preferably 5 parts by mass or less.

(2-1-4) Other Components The coating composition C1 may contain various additives in addition to the components described above. Various additives include, for example, leveling agents, dispersants, ultraviolet absorbers, antioxidants, light stabilizers, antistatic agents, silane coupling agents, anti-aging agents, thermal polymerization inhibitors, colorants, and surfactants. , storage stabilizers, plasticizers, lubricants, antifoaming agents, wettability improvers, paint surface improvers and the like. By containing a dispersant among the above, the dispersibility of the fine particles is improved, and the above-mentioned writing feeling properties are easily satisfied. In addition, by containing a leveling agent among the above, the formed writing quality improving layer 12 has a uniform film thickness without streak-like defects and unevenness, and exhibits an excellent appearance.

Examples of leveling agents include silicone leveling agents, fluorine leveling agents, acrylic leveling agents, and vinyl leveling agents. agents are preferred. In addition, a leveling agent may be used individually by 1 type, and may be used in combination of 2 or more type.

The silicone-based leveling agent is preferably polydimethylsiloxane or modified polydimethylsiloxane, particularly preferably polydimethylsiloxane. In addition, in order to easily satisfy the above-described physical properties of writing feel, the modification rate of the modified polydimethylsiloxane is preferably as low as possible.

The content of the leveling agent in the coating composition C1 is preferably 0.01% by mass or more, particularly preferably 0.05% by mass or more, and further preferably 0.10% by mass or more. preferable. The content of the leveling agent is preferably 5.0% by mass or less, particularly preferably 1.0% by mass or less, and further preferably 0.5% by mass or less. When the content of the leveling agent is within the above range, the effect of the leveling agent is likely to be exhibited.

The dispersant consists of a carboxy group, a hydroxyl group, a sulfo group, a primary amino group, a secondary amino group, a tertiary amino group, an amide group, a quaternary ammonium base, a pyridinium base, a sulfonium base and a phosphonium base in the molecule. A compound having one or more polar groups selected from the group is preferable, and a compound having one or more polar groups of a carboxy group and a hydroxyl group is particularly preferable. One or more of the above polar groups may be introduced into the molecule.

When the compound as the dispersant has a plurality of polar groups, the basic skeleton of the compound is preferably composed of an ester chain, a vinyl chain, an acrylic chain, an ether chain, a urethane chain, or the like. Specifically, acrylic resins, urethane resins, polyester resins and alkyd resins are preferred, acrylic resins, urethane resins and polyester resins are particularly preferred, and acrylic resins are more preferred.

The polar groups may be randomly arranged in the molecule, but are preferably arranged on side chains. Therefore, the compound as the dispersant is preferably an acrylic resin having a carboxyl group and/or a hydroxyl group in its side chain.

The weight average molecular weight of the compound as the dispersant is not particularly limited, but can be selected from a wide range of 100,000 to 900,000. In addition, a dispersing agent may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the dispersant in the coating composition C1 is preferably 0.01% by mass or more, particularly preferably 0.05% by mass or more, and further preferably 0.10% by mass or more. preferable. The content of the dispersant is preferably 2.0% by mass or less, particularly preferably 1.0% by mass or less, and further preferably 0.5% by mass or less. When the content of the dispersant is within the above range, the effect of the dispersant is likely to be exhibited.

(2-2) Thickness of writing feeling improving layer The lower limit of the thickness of the writing feeling improving layer 12 is preferably 0.5 μm or more, particularly preferably 1 μm or more, and further preferably 3 μm or more. Preferably. By setting the lower limit of the thickness of the writing comfort improving layer 12 to the above range, it becomes easier to satisfy the aforementioned physical properties of writing comfort and to obtain good surface hardness. The upper limit of the thickness of the writing comfort improving layer 12 is preferably 20 μm or less, particularly preferably 15 μm or less, and further preferably 10 μm or less. By setting the upper limit of the thickness of the writing quality improving layer 12 to the above range, it becomes easier to satisfy the physical properties of the writing quality described above, and it becomes easier to suppress the occurrence of discoloration and glare.

(3) Optical adjustment layer (3-1) Material of optical adjustment layer The optical adjustment layer 13 of the writing quality improvement sheet 1 in the present embodiment is any material as long as it is made of a material that satisfies the above-described refractive index difference and writing quality. but is preferably formed by curing a coating composition C2 described below. According to the coating composition C2, it is easy to form the optical adjustment layer 13 that satisfies the above refractive index difference and writing feel properties. Moreover, according to the coating composition C2, the surface hardness of the obtained writing feeling improving sheet 1 is increased, and the writing feeling improving sheet 1 has excellent scratch resistance.

The coating composition C2 in this embodiment preferably contains a curable component and fine particles.

(3-1-1) Curable Component As the curable component in the coating composition C2, the same curable component as in the coating composition C1 described above can be used. Among them, it is preferable to use an organic-inorganic hybrid resin from the viewpoint of refractive index and hardness. Inorganic fine particles contained in the organic-inorganic hybrid resin correspond to fine particles described later.

(3-1-2) Fine Particles Any fine particles may be used as long as they satisfy the above-described refractive index difference and physical properties of writing feel. As such fine particles, for example, an organosol of silica fine particles (silica sol) can be preferably used.

As the silica sol, the same organosol of fine silica particles that can be used in the writing comfort improving layer 12 can be used. Such silica sol can also be used as one contained in an organic-inorganic hybrid resin.

The silica fine particles contained in the silica sol are preferably normal colloidal silica particles without voids. As a result, the writing quality improving sheet 1 tends to have excellent scratch resistance.

On the other hand, the silica fine particles contained in the silica sol may be hollow silica fine particles or porous silica fine particles. Hollow silica fine particles and porous silica fine particles have fine voids in the fine particles in an open or closed state. The voids may be closed cells or continuous cells. Since the voids are filled with gas, for example, air with a refractive index of 1, the fine particles themselves have a low refractive index. When the fine particles are uniformly dispersed in the coating film without forming aggregates, the effect of lowering the refractive index of the coating film is high, and at the same time, the transparency is excellent. Hollow silica fine particles and porous silica fine particles having voids have a lower refractive index than ordinary colloidal silica particles having no voids (refractive index n=1.46). Therefore, by using hollow silica fine particles or porous silica fine particles, the refractive index difference described above can be easily satisfied.

The refractive index of the hollow silica fine particles and the porous silica fine particles is preferably 1.10 to 1.65, particularly preferably 1.20 to 1.55, further preferably 1.30 to 1.45. Preferably.

A polymerizable unsaturated group-containing organic compound may be bound to the hollow silica fine particles and the porous silica fine particles. The silica fine particles to which the polymerizable unsaturated group-containing organic compound is bound are obtained by reacting the silanol groups on the surface of the silica fine particles with a polymerizable unsaturated group-containing organic compound having a functional group capable of reacting with the silanol group. be able to. Examples of polymerizable unsaturated groups include radically polymerizable acryloyl groups and methacryloyl groups.

The average particle size of the hollow silica fine particles and the porous silica fine particles is preferably 5 nm or more, particularly preferably 10 nm or more, further preferably 20 nm or more. Further, the average particle diameter of the hollow silica fine particles and the porous silica fine particles is preferably 100 nm or less, particularly preferably 80 nm or less, further preferably 60 nm or less. When the average particle size of the hollow silica fine particles and the porous silica fine particles is within the above range, it becomes easier to satisfy the refractive index difference and the physical properties of the writing feel described above.

Regarding the particle size distribution of the hollow silica fine particles and the porous silica fine particles, the coefficient of variation (CV value) of the particle size is preferably 3% or more, particularly preferably 5% or more, from the viewpoint of the physical properties of writing. , and more preferably 10% or more. Also, from the same viewpoint, the CV value is preferably 200% or less, more preferably 150% or less, particularly preferably 100% or less, and further preferably 75% or less. preferable.

The content of fine particles (especially silica sol) in coating composition C2 is preferably 1% by mass or more, particularly preferably 2% by mass or more, and further preferably 4% by mass or more. Moreover, the content of the fine particles is preferably 40% by mass or less, particularly preferably 30% by mass or less, and further preferably 20% by mass or less. When the content of the fine particles is within the above range, the refractive index difference and the physical properties of the writing feel described above are easily obtained, the surface hardness of the obtained writing feeling improving sheet 1 increases, and the writing feeling improving sheet 1 has scratch resistance. Excellent for

(3-1-3) Photopolymerization Initiator When ultraviolet rays are used as the active energy ray for curing the active energy ray-curable component, the coating composition C2 preferably contains a photopolymerization initiator. . As the photopolymerization initiator, the same photopolymerization initiator as in the coating composition C1 described above can be used. Moreover, the preferable content is also the same as that of the coating composition C1.

(3-1-4) Other Components Coating composition C2 may contain various additives in addition to the components described above. Various additives include, for example, leveling agents, dispersants, ultraviolet absorbers, antioxidants, light stabilizers, antistatic agents, silane coupling agents, anti-aging agents, thermal polymerization inhibitors, colorants, and surfactants. , storage stabilizers, plasticizers, lubricants, antifoaming agents, wettability improvers, paint surface improvers and the like.

Coating composition C2 preferably contains a leveling agent among the above. The preferred type and content of the leveling agent are the same as those of the coating composition C1.

(3-2) Thickness of Optical Adjustment Layer The thickness of the optical adjustment layer 13 is preferably 50 nm or more, more preferably 100 nm or more, particularly preferably 150 nm or more, further preferably 200 nm or more. is preferably The thickness of the optical adjustment layer 13 is preferably 1000 nm or less, particularly preferably 750 nm or less, and more preferably 500 nm or less. When the thickness of the optical adjustment layer 13 is within the above range, the aforementioned difference in refractive index and physical properties of writing feel are easily obtained, and the writing feeling improving sheet 1 tends to be excellent in scratch resistance.

2. Manufacturing Method of Writing Feel-Enhancing Sheet The writing-feel improving sheet 1 according to the present embodiment is preferably manufactured as follows. That is, a coating composition for forming the writing comfort improving layer 12, preferably a coating composition C1, and optionally a solvent, is applied to the base material 11 and cured to form the writing comfort improving layer 12. to form Thereafter, a coating composition for forming the optical adjustment layer 13, preferably coating composition C2, and a coating liquid containing a solvent if desired is applied to the writing comfort improving layer 12 and cured to form the optical adjustment layer. form 13.

Solvents can be used to improve coatability, adjust viscosity, adjust solid content concentration, etc., and can be used without particular limitation as long as it dissolves curable components and the like and disperses fine particles and the like. .

Specific examples of solvents include alcohols such as methanol, ethanol, isopropanol, butanol and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, ethyl lactate and γ-butyrolactone. Ethers such as ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), diethylene glycol monobutyl ether (butyl cellosolve), propylene glycol monomethyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; dimethylformamide , dimethylacetamide, and amides such as N-methylpyrrolidone.

Application of the coating liquid of the coating composition may be carried out by a conventional method such as bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating. After applying the coating liquid of the coating composition, the coating film is preferably dried at 40 to 120° C. for about 30 seconds to 5 minutes.

When the coating composition is active energy ray-curable like the coating compositions C1 and C2, the coating composition is cured by irradiating the coating film of the coating composition with an active energy ray such as an ultraviolet ray or an electron beam. by Ultraviolet irradiation can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation dose of ultraviolet rays is preferably about 50 to 1000 mW/cm ² and a light intensity of about 50 to 1000 mJ/cm ² . On the other hand, the electron beam irradiation can be performed by an electron beam accelerator or the like, and the irradiation dose of the electron beam is preferably about 10 to 1000 krad.

3. Physical Properties The pencil hardness of the writing feeling improving layer 12 and the optical adjustment layer 13 in the writing feeling improving sheet 1 according to the present embodiment is preferably 3H or more. As a result, the writing feeling improving sheet 1 has excellent scratch resistance. In addition, let pencil hardness be the value measured based on JISK5600.

4. Other Configurations The writing feeling improving sheet 1 according to the present embodiment further has other layers as long as it has the substrate 11, the writing feeling improving layer 12, and the optical adjustment layer 13 in that order. good too. For example, an adhesive layer may be formed on the surface of the substrate 11 opposite to the writing comfort improving layer 12, and a release sheet may be laminated on the adhesive layer.

As the adhesive constituting the adhesive layer, those commonly used for optical applications can be used. Adhesives, polyvinyl ether-based adhesives, and the like can be mentioned. Among these, an acrylic pressure-sensitive adhesive that exhibits desired adhesiveness and is excellent in optical properties and durability is preferable.

The thickness of the pressure-sensitive adhesive layer is preferably 5-1000 μm, particularly preferably 7-500 μm, further preferably 10-250 μm.

Examples of release sheets include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, Polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine resin film, etc. is used. Crosslinked films of these are also used. Furthermore, a laminated film of these may be used.

The release surface of the release sheet (especially the surface in contact with the pressure-sensitive adhesive layer) is preferably subjected to a release treatment. Examples of release agents used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 μm.

5. Use of Writing Feel-Enhancing Sheet The writing-feel improving sheet 1 according to the present embodiment is a sheet forming the outermost layer of a touch panel (image display device with a position detection function) in which a touch pen is used. Specifically, it is used by being laminated on a cover material in a touch panel having a display module such as a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence (organic EL) module, or a touch sensor. is preferred. Lamination of the writing comfort improving sheet 1 on the cover material is preferably carried out by adhering via the pressure-sensitive adhesive layer as described above.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, another layer may be interposed between the base material 11 and the writing feeling improving layer 12 in the writing feeling improving sheet 1 and between the writing feeling improving layer 12 and the optical adjustment layer 13 .

EXAMPLES The present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
(1) Formation of writing feeling improving layer An organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530”, silica fine particles with an average particle size of 50 nm (CV value: 28%) as a curable component is added with an acryloyl group. 100 parts by mass of a mixture of a substance to be bound and a polyfunctional (meth)acrylate-based monomer), and 12 of a polyester resin having no polymerizable unsaturated group (manufactured by Toyobo Co., Ltd., product name “Vylon 20SS”) .5 parts by mass and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") as a silicone-based leveling agent were mixed to prepare a coating composition C1 for a writing comfort improving layer. Obtained. The coating composition C1 was diluted with toluene and cyclohexanone to prepare a coating solution.

A polyester film with an easy-adhesion layer (manufactured by Mitsubishi Plastics, Inc., product name: "PET125O300", thickness: 125 μm) as a substrate was coated with the above-obtained coating liquid for a writing comfort improving layer on the side of the easy-adhesion layer. was applied and dried at 70°C for 1 minute. Next, in the atmosphere, an ultraviolet irradiation device (manufactured by GS Yuasa Corporation, product name “Nitrogen purge small conveyor type UV irradiation device CSN2-40”) is irradiated with ultraviolet rays under the following conditions to form a thickness on the substrate. A 3 μm-thick writing comfort improving layer was formed.
[Ultraviolet irradiation conditions]
・Light source: high pressure mercury lamp ・Lamp power: 1.4 kW
・Conveyor speed: 1.2m/min
・Illuminance: 100mW/ ^cm2
・Light intensity: 240 mJ/cm ²

The thickness of the writing comfort improving layer was determined by measuring the total thickness of the substrate and the writing comfort improving layer using a constant pressure thickness gauge (manufactured by Nikon Corporation, product name “MH-15M”). It was calculated by subtracting the thickness of the substrate from the thickness.

(2) Formation of optical adjustment layer An organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530”, silica fine particles with an average particle size of 50 nm (CV value: 28%) as a curable component is combined with an acryloyl group. 100 parts by mass of a mixture of a substance and a polyfunctional (meth)acrylate monomer), and 5 parts by mass of hollow silica sol (manufactured by Nikki Shokubai Kasei Co., Ltd., product name “Sururia 4320”, average particle size: 60 nm) , and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") as a silicone-based leveling agent, to obtain a coating composition C2 for an optical adjustment layer. The coating composition C2 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

The coating liquid for the optical adjustment layer obtained above was applied to the exposed surface of the writing comfort improving layer formed on the substrate, and dried at 70° C. for 1 minute. Next, ultraviolet rays were irradiated under the same conditions as the formation of the writing feeling improving layer to form an optical adjustment layer having a thickness of 250 nm, thereby obtaining a writing feeling improving sheet.

The thickness of the optical adjustment layer in the writing comfort improving sheet was determined by measuring the total thickness of the writing comfort improving sheet using a constant pressure thickness gauge (manufactured by Nikon Corporation, product name “MH-15M”). It was calculated by subtracting the thickness of the substrate and the writing comfort improving layer from the total thickness.

[Example 2]
(1) Formation of writing feeling improving layer An organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530”, silica fine particles with an average particle size of 50 nm (CV value: 28%) as a curable component is added with an acryloyl group. 100 parts by mass of a mixture of a substance to be bound and a polyfunctional (meth)acrylate monomer), crosslinked acrylic polymer resin spherical fine particles (manufactured by Sekisui Plastics Co., Ltd., product name "Techpolymer XX-27LA", 25 parts by mass of average particle size: 1.5 μm, CV value: 23%) and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name “SH28”) as a silicone-based leveling agent. Then, a coating composition C1 for a writing comfort improving layer was obtained. The coating composition C1 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

Using the coating liquid for the writing comfort improving layer obtained above, in the same manner as in Example 1, a writing comfort improving layer having a thickness of 4.5 μm was formed on the substrate.

(2) Formation of optical adjustment layer An organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR TU2362”) as a curable component, a substance obtained by binding an acryloyl group to hollow silica fine particles having an average particle diameter of 60 nm. 100 parts by mass of a mixture with a functional (meth)acrylate monomer) and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") as a silicone leveling agent were mixed. , to obtain a coating composition C2 for the optical adjustment layer. The coating composition C2 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

Using the coating liquid for the optical adjustment layer obtained above, an optical adjustment layer having a thickness of 250 nm was formed on the writing comfort improving layer in the same manner as in Example 1 to obtain a writing comfort improving sheet.

[Example 3]
(1) Formation of writing feeling improving layer In the same manner as in Example 2, a writing feeling improving layer having a thickness of 4.5 µm was formed on the substrate.

(2) Formation of optical adjustment layer An organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR TU2360”) as a curable component, a substance obtained by binding acryloyl groups to hollow silica fine particles having an average particle diameter of 60 nm. 100 parts by mass of a mixture with a functional (meth)acrylate monomer) and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") as a silicone leveling agent were mixed. , to obtain a coating composition C2 for the optical adjustment layer. The coating composition C2 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

Using the coating liquid for the optical adjustment layer obtained above, an optical adjustment layer having a thickness of 250 nm was formed on the writing comfort improving layer in the same manner as in Example 1 to obtain a writing comfort improving sheet.

[Comparative Example 1]
Organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530” as a curable component, a substance obtained by binding acryloyl groups to silica fine particles with an average particle size of 50 nm (CV value: 28%) and polyfunctionality (Meth) acrylate-based monomer) 100 parts by mass, a polyester resin having no polymerizable unsaturated group (manufactured by Toyobo Co., Ltd., product name "Vylon 20SS") 8 parts by mass, and a silicone-based leveling agent was mixed with 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") to obtain a coating composition C1 for a writing comfort improving layer. The coating composition C1 was diluted with toluene and cyclohexanone to prepare a coating solution.

Using the coating liquid for the writing feeling improving layer obtained above, in the same manner as in Example 1, a writing feeling improving layer having a thickness of 4.5 μm was formed on the substrate, and this was used as a writing feeling improving sheet. and

[Comparative Example 2]
Organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530” as a curable component, a substance obtained by binding acryloyl groups to silica fine particles with an average particle size of 50 nm (CV value: 28%) and polyfunctionality Mixture with (meth)acrylate monomer) 100 parts by mass, crosslinked acrylic polymer resin spherical fine particles (manufactured by Sekisui Plastics Co., Ltd., product name “Techpolymer XX-27LA”, volume average particle diameter: 1.5 μm, CV value: 23%) and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") as a silicone-based leveling agent were mixed to form a layer for improving the writing feel. A coating composition C1 was obtained. The coating composition C1 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

Using the coating liquid for the writing feeling improving layer obtained above, in the same manner as in Example 1, a writing feeling improving layer having a thickness of 4.5 μm was formed on the substrate, and this was used as a writing feeling improving sheet. and

[Comparative Example 3]
(1) Formation of writing feeling improving layer In the same manner as in Example 2, a writing feeling improving layer having a thickness of 4.5 µm was formed on the substrate.

(2) Formation of optical adjustment layer An organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530”, silica fine particles with an average particle size of 50 nm (CV value: 28%) as a curable component is combined with an acryloyl group. 100 parts by mass of a mixture of a substance and a polyfunctional (meth)acrylate monomer) and 7 parts by mass of zirconia fine particles (manufactured by Solar Co., product name “NANON5 ZR-020”, average particle size: 10 to 20 nm) and 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name “SH28”) as a silicone-based leveling agent, to obtain a coating composition C2 for an optical adjustment layer. The coating composition C2 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

Using the coating liquid for the optical adjustment layer obtained above, an optical adjustment layer having a thickness of 250 nm was formed on the writing comfort improving layer in the same manner as in Example 1 to obtain a writing comfort improving sheet.

[Comparative Example 4]
Organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industries, Ltd., product name “OPSTAR Z7530” as a curable component, a substance obtained by binding acryloyl groups to silica fine particles with an average particle size of 50 nm (CV value: 28%) and polyfunctionality Mixture with (meth)acrylate monomer) 100 parts by mass, crosslinked acrylic polymer resin spherical fine particles (manufactured by Sekisui Plastics Co., Ltd., product name “Techpolymer XX-27LA”, volume average particle diameter: 1.5 μm, CV value: 23%) was mixed with 0.2 parts by mass of polydimethylsiloxane (manufactured by Dow Corning Toray Co., Ltd., product name "SH28") as a silicone-based leveling agent. A coating composition C1 was obtained. The coating composition C1 was diluted with propylene glycol monomethyl ether and isobutyl alcohol to prepare a coating solution.

Using the coating liquid for the writing feeling improving layer obtained above, in the same manner as in Example 1, a writing feeling improving layer having a thickness of 4.5 μm was formed on the substrate, and this was used as a writing feeling improving sheet. and

[Test Example 1] (Measurement of refractive index)
A polyethylene terephthalate (PET) film having an easy-adhesion layer on one side (manufactured by Toyobo Co., Ltd., product (named "Cosmoshine A4100", thickness 50 μm) on the side opposite to the easy-adhesion layer to form a writing comfort improving layer and an optical adjustment layer under the same conditions as in Examples and Comparative Examples.

Next, the easy-adhesion layer surface of the PET film was rubbed with sandpaper, and painted black with an oil-based pen (manufactured by Zebra Co., product name: "Mackie Black"). Thereafter, the refractive indices of the writing comfort improving layer and the optical adjustment layer obtained by the above method were measured using an Abbe refractometer (Atago Co. , product name “multi-wavelength Abbe refractometer DR-M2”). For Examples 1 to 3 and Comparative Example 3, a value (refractive index difference) was calculated by subtracting the refractive index of the optical adjustment layer from the refractive index of the writing comfort improving layer. Each result is shown in Table 1.

[Test Example 2] (Haze measurement)
The total haze (%) of the writing-improving sheets produced in Examples and Comparative Examples was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with JIS K7136:2000. bottom. Table 1 shows the results.

In addition, one of the release films of an optical adhesive sheet having a release film on both sides of the transparent adhesive layer (manufactured by Lintec, product name “OPTERIA MO-T015”) was peeled off, and the exposed adhesive layer was treated with the adhesive layer in the examples and comparison. It was pasted on the sheet for improving writing comfort produced in Example. Next, the other release film of the optical adhesive sheet was peeled off, and the haze of the resulting laminate was measured in the same manner as described above to obtain the internal haze of the laminate. Then, the external haze (%) of the outermost layer (optical adjustment layer or writing comfort improving layer) opposite to the substrate was calculated by subtracting the internal haze of the laminate from the total haze of the writing comfort improving sheet. Table 1 shows the results.

[Test Example 3] (Measurement of pen tip resistance)
The writing comfort improving sheets produced in Examples and Comparative Examples were placed on a glass substrate with the substrate side down. A touch pen with a hard felt core with a nib diameter of 0.5 mm (manufactured by Wacom, product name " ACK-2003”) is in contact with the pen tip in the vertical direction (the direction in which the axis of the pen tip is perpendicular to the surface of the writing performance improving layer) under a load of 3.92 N to improve the writing performance. It was moved in any one direction parallel to the surface of the sheet at a speed of 100 mm/min. The stylus was attached to a dedicated carriage for measurement, and the carriage was moved to allow the stylus to slide on the writing feeling improving layer.

The pen tip resistance during movement was measured using a universal tester (manufactured by Orientec, product name "Tensilon") to obtain a chart of movement distance (mm) - pen tip resistance (mN). From the obtained measurement chart, the initial movement value (A) and the sliding value (B) of the pen tip resistance were determined. Also, a value was calculated by subtracting the sliding value (B) from the initial movement value (A) of the pen tip resistance. Table 1 shows the results.

[Test Example 4] (Sensory Evaluation of Writing Feel)
The writing comfort improving sheets produced in Examples and Comparative Examples were placed on a glass substrate with the substrate side facing down. Using the same touch pen as in Test Example 3, the writing feeling was evaluated on the surface of the outermost layer (optical adjustment layer or writing feeling improving layer) on the side opposite to the substrate in the writing feeling improving sheet. In the evaluation, a pencil (manufactured by Mitsubishi Pencil Co., Ltd., Mitsubishi Pencil Uni B) was used on a five-ply paper (manufactured by Kokuyo S&T Co., Campus Note A Ruled No-201A) with a writing pressure of about 400 g. A writing feeling close to that was rated as good, and a writing feeling far from that was rated as poor. The evaluation was made by 5 panelists, with ◎ indicating that all 5 felt good, O indicating that 3 or 4 people felt good, and 0 if 1 or 2 felt good. The sample was rated as Δ, and the sample that all five panelists felt was defective was rated as x. Table 1 shows the results.

[Test Example 5] (Screen evaluation-Evaluation of discoloration)
A tablet terminal (manufactured by Apple Inc.) in which the writing comfort improving sheets produced in Examples and Comparative Examples are placed with the substrate side facing down and the entire surface is displayed in green (RGB values (R, G, B) = 0, 255, 0) , product name “iPad (registered trademark)”, resolution: 264 ppi), and the discoloration was visually evaluated according to the following criteria. Table 1 shows the results.
⊚: Discoloration due to the sheet for improving writing comfort was not observed.
◯: Slight discoloration caused by the sheet for improving writing comfort was observed.
x: Discoloration caused by the sheet for improving writing comfort was confirmed.

[Test Example 6] (Screen Evaluation-Glitter Evaluation)
A tablet terminal (manufactured by Apple Inc.) in which the writing comfort improving sheets produced in Examples and Comparative Examples are placed with the substrate side facing down and the entire surface is displayed in green (RGB values (R, G, B) = 0, 255, 0) , product name “iPad (registered trademark)”, resolution: 264 ppi), and the glare was visually evaluated according to the following criteria. Table 2 shows the results.
⊚: No glare caused by the sheet for improving writing comfort was observed.
◯: Slight glare caused by the sheet for improving the writing feel was observed.
x: Glare caused by the sheet for improving writing comfort was confirmed.

[Test Example 7] (Measurement of pencil hardness)
The pencil hardness of the surface on the side of the writing comfort improving layer (the surface of the writing comfort improving layer) in the laminates of the base material and the writing comfort improving layer produced in Examples and Comparative Examples was measured using an electric pencil scratch hardness tester (Yasuda Seiki Seisakusho Co., Ltd.). 553-M1 (product name)), and measured according to JIS K5600. In addition, the pencil hardness of the surface on the optical adjustment layer side (the surface of the optical adjustment layer) of the writing comfort improving sheets produced in Examples and Comparative Example 3 was measured in the same manner. Table 2 shows the results.

[Test Example 8] (Scratch resistance test)
The surface of the writing-improving layer side (the surface of the writing-improving layer) in the laminates of the base material and the writing-improving layer produced in Examples and Comparative Examples was treated with #0000 steel wool at a weight of 250 g/cm ² . A load of 10 cm was rubbed back and forth 10 times. The surface of the writing comfort improving layer was visually observed under a three-wavelength fluorescent lamp, and the scratch resistance was evaluated according to the following criteria. The surface of the optical adjustment layer side (the surface of the optical adjustment layer) of the writing comfort improving sheets produced in Examples and Comparative Example 3 was similarly evaluated for scratch resistance. Table 2 shows the results.
O: No damage was observed.
x: Scratches were confirmed.

As is clear from Table 1, the writing-feel improving sheets produced in Examples had excellent writing feel with a touch pen, and the generation of discoloration due to the writing-feel improving sheet was suppressed. In addition, the writing comfort improving sheets produced in the examples were suppressed in glare and had high surface hardness (abrasion resistance).

The writing comfort improving sheet of the present invention is suitably used as the outermost layer of a touch panel in which a touch pen is used.

DESCRIPTION OF SYMBOLS 1... Writing feeling improvement sheet 11... Base material 12... Writing feeling improving layer 13... Optical adjustment layer

Claims (7)

A touch panel equipped with a touch pen, comprising a writing comfort improving sheet on the outermost layer of the touch panel,
The writing quality improving sheet comprises a base material, a writing quality improving layer provided on one side of the base material, and an optical adjustment layer provided on the opposite side of the writing quality improving layer to the base material. with
The total haze of the writing comfort improving sheet is 5% or more and 40% or less,
the refractive index of the optical adjustment layer is less than the refractive index of the writing comfort improving layer;
The surface of the optical adjustment layer side of the writing comfort improvement sheet is vertically contacted with a pen tip of a touch pen with a hard felt core and a pen tip diameter of 0.5 mm under a load of 3.92 N, and the optical adjustment is performed. The initial movement value (A) and the sliding value (B) of the pen tip resistance force (mN) when moved in any direction parallel to the surface of the layer at a speed of 100 mm / min are obtained by the following formula (a) and formula Satisfying the relationship of (b) 0 < initial value (A) - sliding value (B) ... (a)
350 ≤ initial value (A) … (b)
A touch panel characterized by: 2. The touch panel according to claim 1, wherein the writing comfort improving layer is a layer obtained by curing a coating composition containing a curable component and fine particles. A touch panel equipped with a touch pen, comprising a writing comfort improving sheet on the outermost layer of the touch panel,
The writing quality improving sheet comprises a base material, a writing quality improving layer provided on one side of the base material, and an optical adjustment layer provided on the opposite side of the writing quality improving layer to the base material. with
The writing comfort improving layer is a layer obtained by curing a coating composition containing a curable component and fine particles,
The thickness of the writing comfort improving layer is 3 μm or more and 20 μm or less,
The fine particles are inorganic fine particles that are not organosols with an average particle size of 0.5 μm or more and 2 μm or less, inorganic fine particles as organosols with an average particle size of 1 nm or more and 300 nm or less, and an average particle size of 1.0 μm or more. , one or more organic fine particles of 1.5 μm or less ,
the refractive index of the optical adjustment layer is less than the refractive index of the writing comfort improving layer;
A pen tip of a touch pen with a hard felt core and a pen tip diameter of 0.5 mm is brought into vertical contact with the surface of the optical adjustment layer side of the writing quality improving sheet under a pressure condition of a load of 3.92 N, and the optical adjustment is performed. The initial movement value (A) and the sliding value (B) of the pen tip resistance force (mN) when moved in any direction parallel to the surface of the layer at a speed of 100 mm / min are obtained by the following formula (a) and formula Satisfying the relationship of (b) 0 < initial value (A) - sliding value (B) ... (a)
350 ≤ initial value (A) … (b)
A touch panel characterized by: 4. The touch panel according to claim 3, wherein the coating composition contains 10% by mass or more and 40% by mass or less of the organic fine particles as the fine particles. Any one of claims 2 to 4, wherein the coating composition contains, as the fine particles, inorganic fine particles having a polymerizable unsaturated group on the surface, which are inorganic fine particles as an organosol. Described touch panel. 6. The touch panel according to any one of claims 1 to 5, wherein the optical adjustment layer has a refractive index of 1.2 or more and 1.5 or less. The touch panel according to any one of claims 1 to 6, wherein the optical adjustment layer is a layer obtained by curing a coating composition containing a curable component and fine particles.

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