TWI706863B - Film to improve writing feeling - Google Patents

Abstract

The subject of the present invention is to provide a film for improving the writing sensation of a stylus pen having an excellent writing sensation.

The solution of the present invention is a film 1 for improving the feeling of writing. It has a layer 12 for improving the feeling of writing. There are 8 or more and 30 or less in the area of 10925.76μm ² on the surface, and the height is 1μm or more and 3μm or less. , And the maximum cross-sectional area of the cross-section in the plane direction is 10.2 μm ² or more protrusions, and there are 20 or more protrusions with a height exceeding 0 μm and less than 1 μm.

Description

Film to improve writing feeling

The present invention relates to a film that improves the writing feeling of the outermost layer constituting a touch panel using a stylus pen.

In recent years, in various electronic devices, most of them utilize touch panels that are both a display device and an input means. In such a touch panel, in addition to those who use fingers for input, there are also those who use a stylus for input. If the stylus is used, it is possible to perform more precise and high-precision input operations than using fingers. However, usually, the display module of the touch panel is rigid. Therefore, the feeling of writing with a stylus pen is different from the feeling of writing on paper with a pencil or pen, and it is hard to say that it is good.

In order to solve the problem of the feeling of writing on the touch panel using a stylus, it has been studied to stick a film that improves the feeling of writing on the outermost surface of the touch panel (hereinafter, sometimes referred to as "the film for improving the feeling of writing"). As such a film, for example, Patent Document 1 discloses a touch-sensitive film comprising: a transparent base film; on at least one surface of the transparent base film, linear projections having a mesh structure are formed, and the mesh structure has regular A plurality of cells are arranged, and the linear convex part occupies 5 to 80% of the entire surface of the touch-sensitive film.

In addition, Patent Document 2 discloses a tactile improved film, which is a tactile improved film having a surface shape with a maximum height ripple (W _EM ) conforming to JIS B0610 of 15 μm or more. Of particles.

[Prior Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Application Publication No. 2015-054417

Patent Document 2: Japanese Patent Application Publication No. 2014-137640

However, according to the inventions disclosed in Patent Documents 1 and 2, the pen tip feels stuck or slippery, and the sound or vibration when writing is different from when writing on paper with a pencil or pen, and it is not possible to fully use a pencil or a pen. The feeling of writing with a pen, etc. when writing on paper.

The present invention is completed in view of such a solid state, and aims to provide a film for improving the writing feeling of a stylus pen with excellent writing feeling.

In order to achieve the above objectives, the first invention provides a film for improving writing feeling, which is characterized by having: a layer for improving writing feeling. There are 8 or more and 30 or less in the surface area of 10925.76 μm ² , and height There are 20 or more protrusions that are 1 μm or more and 3 μm or less, and have a maximum cross-sectional area of 10.2 μm ² or more in the plane direction, and have a height of more than 0 μm and less than 1 μm (Invention 1).

Regarding the film for improving writing feeling of the above invention (Invention 1), by having a layer for improving writing feeling on the surface (surface contacted by the stylus pen) with the above-mentioned protrusions, the feeling of writing with the stylus pen is improved. Gives a better sense of resistance and friction. The combination of these feelings makes the writing feeling of the stylus similar to the feeling when writing on paper with a pencil or pen, and becomes excellent.

In the above invention (Invention 1), the layer for improving writing feeling is preferably a layer formed by curing a coating composition containing a curable component and fine particles (Invention 2).

Regarding the film for improving the writing feeling of the present invention, the writing feeling using a stylus pen is excellent.

1‧‧‧Film to improve writing

11‧‧‧Substrate film

12‧‧‧Improve the sense of writing

Fig. 1 is a cross-sectional view of a film for improving writing feeling related to an embodiment of the present invention.

2 is an observation image (color) of an optical interference type surface shape observation device (VSI mode) on the surface of the writing-improving layer of the writing-improving film of Example 1. FIG.

The following describes embodiments of the present invention.

Regarding the writing-improving film 1 of this embodiment, it is a film that constitutes the outermost layer of a touch panel using a stylus pen. Preferably, as shown in FIG. 1, a base film 11 and a base film formed on 11 is formed by the layer 12 for improving writing feeling on one side. However, the film 1 for improving the writing feeling of this embodiment may be formed of a single layer or three or more layers.

1. Physical properties

Regarding the surface of the writing-improving layer 12 of the writing-improving film 1 of this embodiment (the surface touched by the stylus; hereinafter sometimes referred to as "the surface of the writing-improving film 1"), on the surface Within the area of 10925.76μm ² , there are 8 or more and 30 or less protrusions with a height of 1 μm or more and 3 μm or less, and the maximum cross-sectional area of the cross section in the plane direction is 10.2 μm ² or more (hereinafter sometimes referred to as " Large protrusions".) At the same time, there are 20 or more protrusions with a height of more than 0 μm and less than 1 μm (hereinafter, sometimes referred to as "small protrusions"). In addition, the "maximum cross-sectional area of the cross-section in the plane direction of the film for improving writing feeling" refers to the area of the smallest shape that can surround the protrusion in a plan view.

As described above, if the large protrusions and small protrusions are present at the above-mentioned density on the surface of the film 1 for improving the writing feeling, the small protrusions are usually located in the valleys of the large protrusions. If the shape of the surface of the film 1 for improving the writing feeling has this shape, the writing with the stylus can be given a better sense of resistance and friction. The combination of these feelings makes the writing feeling of the stylus similar to the feeling when writing on paper with a pencil or pen, and becomes excellent.

Furthermore, as a stylus, for example, in addition to a stylus with a hard felt core with a tip diameter of 0.1~5mm, a stylus with a polyacetal core can also be used, no matter what kind of touch pen is used. , Can obtain the above effects. In addition, in this specification, the "pen" used as a reference for the sense of writing includes a ball pen, a felt pen, a fountain pen, etc., and a fountain pen is preferred.

From the viewpoint of the above-mentioned effects, in the range of the area of 10925.76 μm ² of the surface of the film 1 for improving writing feeling, there are preferably 8 or more large protrusions, and particularly preferably 9 or more. In particular, from the viewpoint of obtaining the writing feeling of a pencil on paper, it is preferable that there are 11 or more. On the other hand, the above-mentioned large protrusions are preferably 30 or less, and more preferably 20 or less. In addition, as described above, protrusions having a maximum cross-sectional area of 10.2 μm ² or more are classified as large protrusions, but the upper limit of the maximum cross-sectional area of existing protrusions is not particularly limited. However, the maximum cross-sectional area of the above-mentioned large protrusions is preferably 400 μm ² or less, particularly preferably 300 μm ² or less, and more preferably 100 μm ² or less from the viewpoint of eliminating variations in writing feeling.

From the viewpoint of obtaining the same excellent writing feeling, in the area of 10925.76 μm ² on the surface of the film 1 for improving writing feeling, there are preferably 15 or more small protrusions, especially 20 or more. More preferably, there are more than 35. In particular, from the viewpoint of obtaining the writing feeling of a fountain pen on paper, it is preferable to have 50 or more. In addition, the above-mentioned small protrusions are preferably 100 or less, particularly preferably 75 or less. The maximum cross-sectional area of the small protrusions is preferably 0.03 μm ² or more, especially 0.3 μm ² or more, and more preferably 0.5 μm ² or more. On the other hand, the maximum cross-sectional area of the small protrusions is preferably 11 μm ² or less, particularly preferably 10 μm ² or less, and more preferably 8 μm ² or less.

The above-mentioned large protrusions and small protrusions are preferably the protrusions obtained by observing the image in the range of 91.2μm×119.8μm using the vertical scanning interferometry method of the optical interference type surface profile observation device on the surface of the film 1 for improving the writing feeling . That is, the height, maximum cross-sectional area, and number of the above-mentioned large protrusions and small protrusions are preferably those measured by a vertical scanning interferometry using an optical interference type surface profile observation device in an observation image in the range of 91.2 μm×119.8 μm. The specific device and measurement method are as shown in the test example described later.

In addition, the height is 1 μm or more and 3 μm or less, and the maximum cross-sectional area of the cross-section in the plane direction of the film 1 for improving writing feeling is less than 10.2 μm ² and it is preferable that there is no protrusion. This is because when writing, the protrusion may peel off and the writing feeling may change.

Regarding the writing feeling-improving film 1 of the present embodiment, the predetermined characteristics in the pen sliding test are preferably within a predetermined range. Specifically, for the surface of the writing-improving layer 12 of the writing-improving film 1, the stylus tip of a stylus with a stylus core with a pen tip diameter of 0.5 mm is used in the vertical direction under a pressure condition of a load of 3.92N The contact is moved in any direction parallel to the surface of the writing-improving layer 12 at a speed of 100 mm/min, and the pen tip resistance (mN) is measured, and a graph of movement distance (mm)-pen tip resistance (mN) is obtained. The obtained movement distance (mm)-pen tip resistance (mN) graph was Fourier transformed using Excel (registered trademark; software made by Microsoft Corporation) to obtain a frequency (Hz)-amplitude (-) graph. From the obtained frequency (Hz)-amplitude (-) graph, the average value, maximum value, and number of peaks of the amplitude in the frequency range of 1 to 2 Hz are obtained. If each is in the range shown below, the writing feeling of the film 1 for improving writing feeling can be made more excellent.

Here, the "pen tip resistance" refers to the resistance applied to the pen tip when the stylus pen is moved under the above conditions. In addition, the above-mentioned "average value of amplitude" refers to the sum of the maximum value and the minimum value of the peaks in the frequency range of 1 to 2 Hz, divided by these numbers. In addition, the aforementioned "number of crests" refers to the number of crests having an amplitude of 1.5 or more in the frequency range of 1 to 2 Hz.

The average value of the aforementioned amplitude is preferably 1.2 or more, particularly preferably 1.3 or more. In particular, from the viewpoint of obtaining the writing feeling of a pencil on paper, 1.5 or more is preferable. In addition, the average value of the aforementioned amplitude is preferably 10 or less, particularly preferably 8 or less, and more preferably 4 or less. The maximum value (maximum amplitude value) of the above-mentioned amplitude is preferably 1.0 or more, especially 2.0 or more, and more preferably 2.6 or more. In particular, from the viewpoint of obtaining the writing feeling of a pen on paper, 3.0 or more is preferable. In addition, the maximum value of the aforementioned amplitude is preferably 10 or less, particularly preferably 8 or less, and more preferably 5 or less. The number of peaks (amplitude number) of the above amplitude is preferably 3 or more, particularly preferably 5 or more, and more preferably 7 or more. In addition, the number of crests of the above amplitude is preferably 30 or less, particularly preferably 25 or less, and more preferably 15 or less.

The specific method of obtaining the above-mentioned moving distance (mm)-pen tip resistance (mN) graph is as shown in the test example described later.

2. Each component

(1) The layer to improve the sense of writing

(1-1) Materials to improve the sense of writing

In the writing-improving film 1 of the present embodiment, the writing-improving layer 12 can be formed of any material as long as it has the above-mentioned physical properties, that is, the surface shape formed by the above-mentioned large and small protrusions. It is formed by hardening the coating composition C described below. If the coating composition C is used, the writing-improving layer 12 satisfying the above physical properties can be easily formed.

The coating composition C of the present embodiment preferably contains a curable component and fine particles.

(1-1-1) Hardening ingredients

The curable component is a component that is hardened by a trigger of active energy rays or heat, and examples thereof include active energy ray hardenable 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 layer 12 for improving writing feeling formed or the heat resistance of the base film 11, etc.

As the active energy ray curable component, it is preferable to exhibit a predetermined hardness by irradiation with active energy rays, and to achieve the above-mentioned physical properties in relation to fine particles.

Specific active energy ray curable components include polyfunctional (meth)acrylate monomers, (meth)acrylate prepolymers, active energy ray curable polymers, etc., among which polyfunctional A (meth)acrylate-based monomer and/or a (meth)acrylate-based prepolymer is preferable, and a polyfunctional (meth)acrylate-based monomer is more preferable. The polyfunctional (meth)acrylate-based monomer and the (meth)acrylate-based prepolymer may be used alone, respectively, or both may be used in combination. In addition, in this specification, the term "(meth)acrylate" means both acrylate and methacrylate. Other similar terms are also the same.

Examples of polyfunctional (meth)acrylate monomers include, for example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and new Pentylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxytrimethyl acetate neopentyl glycol di(meth)acrylate, dicyclopentane di(meth) Acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate phosphate, allylcyclohexyl 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, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol Multifunctionality of acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide modified dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. (Meth)acrylate. These can be used individually by 1 type, and can also be used in combination of 2 or more types.

On the other hand, examples of (meth)acrylate-based prepolymers include, for example, polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, and polyol acrylate-based prepolymers. And other prepolymers.

The polyester acrylate-based prepolymer can be esterified with (meth)acrylic acid, for example, by condensing a polycarboxylic acid with a polyol, and the hydroxyl groups of a polyester oligomer having hydroxyl groups at both ends can be esterified. Or it can be obtained by esterifying the terminal hydroxyl group of the oligomer obtained by adding alkylene oxide to a polycarboxylic acid with (meth)acrylic acid.

Epoxy acrylate-based prepolymers, for example, can be combined with the oxirane ring of a bisphenol-type epoxy resin or novolac-type epoxy resin with a relatively low molecular weight, and (methyl) Acrylic acid is obtained by reaction and esterification.

Urethane acrylate-based prepolymers, for example, polyurethane oligomers obtained by reacting polyether polyols or polyester polyols with polyisocyanate (meth)acrylic acid Obtained by esterification.

The polyol acrylate-based prepolymer can be obtained, for example, by esterifying the hydroxyl group of a polyether polyol with (meth)acrylic acid.

The above prepolymers may be used singly or in combination of two or more kinds.

In addition, it is preferable to use an organic-inorganic hybrid resin as the active energy ray curable component. As the organic-inorganic hybrid resin, preferably, silica particles are bonded to an organic compound having a polymerizable unsaturated group via a silane coupling agent or the like. In addition, the silica microparticles contained in the organic-inorganic hybrid resin function as a binder (binder) as a silica sol, and are not included in the microparticles described later.

When an organic-inorganic hybrid resin is used, the surface shape formed by the above-mentioned large and small protrusions can be easily obtained by the action of silica sol. Therefore, even if spherical organic fine particles are used for the fine particles to be described later, the surface shape can be easily obtained, and thereby, the optical characteristics of the formed layer 12 for improving writing feeling can be improved.

(1-1-2) Fine particles

The fine particles may be any one of inorganic fine particles and organic fine particles. For example, from the viewpoint of imparting high surface hardness to the layer 12 for improving the writing feeling, inorganic fine particles are preferred, and from the viewpoint of making the optical properties of the layer 12 for improving writing feeling higher, organic fine particles are preferred. In addition, the shape of the fine particles may be spherical or non-spherical. If it is non-spherical, it may have an indefinite shape, or may have a shape with a high aspect ratio such as a needle shape or a scale shape. Here, the "indefinite shape" refers to a shape that is not a regular shape such as a spherical shape or an elliptical shape, but has a large number of irregular corners or faces. In addition, the fine particles may be used singly or in combination of two or more kinds.

In this embodiment, in order to achieve the surface shape formed by the above-mentioned large protrusions and small protrusions, amorphous fine particles with an average particle diameter of 0.5 μm or more and 15 μm or less, or an average particle diameter of 1.7 μm or more and 15 μm or less are used. Of spherical particles. Amorphous fine particles are usually inorganic fine particles. The spherical fine particles may be either inorganic fine particles or organic fine particles, but from the viewpoint of optical properties, organic fine particles are preferred. In addition, from the viewpoint of obtaining the writing feeling of a pencil, amorphous fine particles are preferable, and from the viewpoint of obtaining the writing feeling of a pen, spherical fine particles are preferable.

Examples of inorganic fine particles include, for example, silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, cerium oxide, etc. Metal oxides; fine particles formed by metal fluorides such as magnesium fluoride and sodium fluoride. Among the above, in terms of less influence on the optical characteristics, silica and alumina are preferred, especially silica is preferred, and amorphous silica is further preferred. Furthermore, the surface of the inorganic fine particles may be chemically modified with organic compounds or the like.

Examples of organic microparticles include, for example, silicone microparticles, melamine resin microparticles, acrylic resin microparticles (for example, polymethyl methacrylate resin microparticles, etc.), acrylic-styrene copolymer microparticles, and polycarbonate Microparticles, polyethylene microparticles, polystyrene microparticles, benzoguanamine resin microparticles, etc. These resins can also be bridged. Among the above, from the viewpoint of optical characteristics and hardness, acrylic resin particles are preferred, especially polymethyl methacrylate resin particles are preferred, and spherical polymethyl methacrylate resin particles are more preferred. , It is best to bridge polymethyl methacrylate resin particles with true spherical shape.

The average particle diameter of the amorphous fine particles is preferably 0.5 μm or more, particularly preferably 0.75 μm or more, and more preferably 1.0 μm or more. In addition, the average particle diameter of the amorphous fine particles is preferably 15 µm or less, more preferably 10 µm or less, particularly preferably 8 µm or less, and more preferably 4.0 µm or less. By setting the average particle diameter of the amorphous fine particles within the above-mentioned range, the surface shape formed by the above-mentioned large protrusions and small protrusions can be easily obtained. In addition, the average particle diameter of the fine particles in this specification is the primary particle diameter measured by the Zeta potential measurement method.

The average particle diameter of the spherical fine particles is preferably 1.7 μm or more, particularly preferably 2.0 μm or more, and more preferably 2.5 μm or more. In addition, the average particle diameter of the spherical fine particles is preferably 15 μm or less, more preferably 10 μm or less, particularly preferably 8 μm or less, and more preferably 5 μm or less. By setting the average particle diameter of the spherical fine particles within the above range, the surface shape formed by the above-mentioned large protrusions and small protrusions can be easily obtained.

Regarding the particle size distribution of the above-mentioned fine particles, from the viewpoint of forming the surface shape of the layer 12 for improving writing feeling, the coefficient of variation (CV value) of the particle diameter expressed by the following formula is preferably 20% or more, especially 40% or more Preferably, it is more preferably more than 70%. In addition, from the same viewpoint, the aforementioned CV value is preferably 200% or less, particularly preferably 175% or less, and more preferably 100% or less.

Coefficient of variation of particle size (CV value) (%)=(standard deviation particle size/average particle size)×100

In addition, the coefficient of variation (CV value) of the particle size is a value measured by a laser diffraction scattering particle size distribution measuring device (manufactured by Horiba Manufacturing Co., Ltd., product name "LA-920").

The content of the microparticles in the coating composition C is preferably 3% by mass or more, particularly preferably 7% by mass or more, and more preferably 10% by mass or more. In addition, the content of the above-mentioned fine particles is preferably 40% by mass or less, particularly preferably 30% by mass or less, and more preferably 15% by mass or less. By setting the content of the fine particles within the above range, the surface shape formed by the above-mentioned large protrusions and small protrusions can be easily obtained.

(1-1-3) Photopolymerization initiator

When using ultraviolet rays as the active energy ray for curing the active energy ray curable component, the coating composition C preferably contains a photopolymerization initiator. By containing the photopolymerization initiator in this way, the active energy ray curable component can be efficiently polymerized, and the polymerization curing time and the amount of ultraviolet radiation can be reduced.

As such a photopolymerization initiator, for example, 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-phenylpropane- 1-ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propan-1-one, 4-(2-hydroxyl Ethoxy) phenyl-2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichloro Benzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methyl thioxanthone, 2 -Ethylthioxanthone (2-ethylthioxanthone), 2-chlorothioxanthone (2-chlorothioxanthone), 2,4-dimethylthioxanthone (2,4-dimethylthioxanthone), 2,4-diethylthioxanthone Xanthone (2,4-diethylthioxanthone), benzyl dimethyl ketal (benzyl dimethyl ketal), acetophenone dimethyl ketal (acetophenone dimethyl ketal), p-dimethylaminobenzoic acid ester (p- dimethylaminobenzoic acid ester), oligomeric [2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzyl diphenyl Phosphine oxides, etc. These can be used individually by 1 type, and can also be used in combination of 2 or more types.

The content of the photopolymerization initiator in the coating composition C, relative to 100 parts by mass of the active energy ray curable component, the lower limit is preferably 0.01 parts by mass or more, especially 0.1 parts by mass or more, and further 1 part by mass or more is more preferable. In addition, 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.

(1-1-4) Other ingredients

The coating composition C may contain various additives in addition to the above-mentioned components. Examples of various additives include, for example, leveling agents, ultraviolet absorbers, oxidation inhibitors, light stabilizers, electrification inhibitors, silane coupling agents, aging inhibitors, thermal polymerization inhibitors, colorants, interfacial activity Agents, preservation stabilizers, plasticizers, lubricants, defoamers, wettability modifiers, coating modifiers, etc.

(1-2) The thickness of the layer that improves the writing feeling

The lower limit of the thickness of the layer 12 for improving writing sensation is preferably 0.5 μm or more, particularly preferably 0.7 μm or more, and more preferably 1.0 μm or more. By setting the lower limit of the thickness of the writing feeling-improving layer 12 to the above, it is easy to satisfy the above-mentioned physical properties, and good scratch resistance can be obtained. In addition, the upper limit of the thickness of the layer 12 for improving the writing feeling is preferably 20 μm or less, particularly preferably 15 μm or less, and more preferably 10 μm or less. By setting the upper limit of the thickness of the writing feeling-improving layer 12 to the above, it is easy to satisfy the above physical properties.

(2) Substrate film

The base film 11 may be appropriately selected from a panel user suitable for using a stylus pen, and it is preferable to select a plastic film having good affinity with the layer 12 for improving the writing feeling.

Examples of the plastic film include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, and polyethylene film. , Polyolefin film such as polypropylene film, cellophane, cellulose diacetate film, cellulose triacetate film, cellulose acetate butyl film, polyvinyl chloride film, polyvinylidene chloride film, Polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polyether ketone film, polyether ether ketone film, polyether turpentine film, polyether ether Amine film, fluororesin film, polyamide film, acrylic resin film, polyurethane resin film, norbornene polymer film, cyclic olefin polymer film, cyclic conjugated diene polymer film, vinyl resin Plastic films such as cyclic hydrocarbon polymer films or laminated films of these. Among them, in combination with the above-mentioned layer 12 for improving the writing feeling, polyethylene terephthalate film, polycarbonate film, norbornene-based polymerizers that can maintain the writing feeling of the stylus well are preferred. Film, etc., especially polyethylene terephthalate film is preferred.

In addition, in the base film 11, the purpose is to improve the adhesion with the layers provided on the surface thereof (the layer 12 for improving the writing feeling, the adhesive layer described later, etc.), and it can be used on one or both sides as needed, by Surface treatment is performed by primer treatment, oxidation method, and unevenness method. Examples of the oxidation method include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone-ultraviolet treatment, etc., and examples of the roughening method include sandblasting, solvent treatment, and the like. These surface treatment methods can be appropriately selected according to the type of base film 11. As an example, a plastic film with an easy-adhesion layer formed by primer treatment is particularly preferably a polyethylene terephthalate film.

The thickness of the substrate film 11 is preferably 15 to 300 μm, particularly preferably 30 to 200 μm, and more preferably 90 to 150 μm.

3. Manufacturing method of film to improve writing feeling

Regarding the writing-improving film 1 of this embodiment, a coating composition containing a layer 12 for improving writing-sensation, a coating liquid containing a preferable coating composition C and a solvent as necessary, is applied to the substrate film 11 It is manufactured by coating and hardening to form the layer 12 for improving writing feeling.

The solvent can be used to improve the coating properties, adjust the viscosity, and adjust the solid content concentration. As long as it can dissolve the curable component, etc., disperse fine particles, etc., it can be used without particular limitation.

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; ethyl acetate, Esters such as butyl acetate, ethyl lactate, and gamma-butyrolactone; ethylene glycol monomethyl ether (methyl serosol), ethylene glycol monoethyl ether (ethyl serosol), diethylene glycol monobutyl Ether (butyl serosol), propylene glycol monomethyl ether and other ethers; benzene, toluene, xylene and other aromatic hydrocarbons; dimethylformamide, dimethylacetamide, N-methylpyrrolidone (N-methylpyrrolidone) and other amides.

The application of the coating liquid of the coating composition may be carried out by a conventional method, for example, bar coating method, knife coating method, roll coating method, blade coating method, die coating method, The gravure coating method is performed. Preferably, after coating the coating liquid of the coating composition, the coating film is dried at about 40 to 120°C for 30 seconds to 5 minutes.

For example, when the coating composition of the coating composition C is curable with active energy rays, curing of the coating composition can be performed by irradiating the coating film of the coating composition with active energy rays such as ultraviolet rays and electron rays. Ultraviolet irradiation, high pressure mercury lamp may be used, melted H lamp, a xenon lamp or the like, the irradiation amount of ultraviolet rays, illuminance 50 ~ 1000mW / cm ^2, light quantity of 50 ~ 1000mJ / cm ² preferably about. On the other hand, electron beam irradiation can be carried out using an electron beam accelerator, etc. The amount of electron beam irradiation is preferably about 10~1000krad.

4. Other

Regarding the writing-improving film 1 of this embodiment, it is preferable to have the writing-improving layer 12 as the outermost surface, and having the base film 11 and the writing-improving layer 12, but it can also be used to improve writing Between the layer 12 and the base film 11, or on the side of the base film 11 that is not in contact with the writing-improving layer 12, there are further other layers. For example, an adhesive layer may be formed on the surface of the base film 11 that is not in contact with the writing-improving layer 12, or a release sheet may be further laminated on the adhesive layer.

The adhesive constituting the adhesive layer is not particularly limited, and conventional adhesives such as acrylic adhesives, rubber-based adhesives, and silicone-based adhesives can be used.

In addition, as for the writing-improving film 1 of this embodiment, as long as the surface shape satisfies the above requirements, it may be formed of a single layer, for example, a film (resin film) formed of a single layer, a glass film, or the like.

The embodiments described above are described for easy understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment includes all design changes or equivalents belonging to the technical scope of the present invention.

For example, another layer may be interposed between the base film 11 of the film 1 for improving writing feeling and the layer 12 for improving writing feeling.

[Example]

Hereinafter, the present invention will be explained more specifically with examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

Polyfunctional urethane acrylate (manufactured by Arakawa Chemical Industry Co., Ltd., product name "BEAMSET 575CB"), 15 mass parts as a curable component, 100 parts by mass (represents the converted value of solid content. The other components are the same below.) One part of amorphous silica fine particles (CV value 88%) having an average particle diameter of 1.5 μm and 5 parts by mass of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator were mixed to obtain a coating composition. This coating composition was diluted with propylene glycol monomethyl ether to prepare a coating liquid.

A polyester film with an easy-adhesion layer (manufactured by Toyobo Co., Ltd., product name "Cosmoshine A4300", thickness: 125μm) of a polyester film with an easy-adhesion layer as a base film is coated with the coating solution obtained above to Dry at 70°C for 1 minute. Next, in the atmosphere, an ultraviolet irradiation device (manufactured by GS Yuasa, product name "Nitrogen-filled Small Conveyor Type UV Irradiation Device CSN2-40") is irradiated with ultraviolet rays under the following conditions to form a layer with a thickness of 5μm to improve writing feeling. And a film that improves writing feeling is obtained.

[Ultraviolet radiation conditions]

‧Light source: high pressure mercury lamp

‧Light power: 1.4kW

‧Conveyor belt speed: 1.2m/min

‧Illuminance: 100mW/cm ²

‧Light quantity: 240mJ/cm ²

Furthermore, the thickness of the writing-improving layer of the above-mentioned writing-improving film is measured by using a constant pressure gauge (manufactured by Nikon, product name "MH-15M") to measure the total thickness of the writing-improving film. The total thickness is calculated by subtracting the thickness of the base film.

[Examples 2 to 4, Comparative Examples 1 to 3]

As shown in Table 1, except that the material and the blending ratio of the coating composition, and the thickness of the layer for improving the feeling of writing were changed, a film for improving writing feeling was produced in the same manner as in Example 1.

Here, the details of the abbreviation described in Table 1 are as follows.

A: Multifunctional urethane acrylate (manufactured by Arakawa Chemical Industry Co., Ltd., product name "BEAMSET 575CB")

B: Organic-inorganic hybrid resin (manufactured by Arakawa Chemical Industry Co., Ltd., product name "OPSTER Z7530", mixed with polyfunctional (meth)acrylate monomers) made by bonding acryl groups to silica particles )

C: Amorphous silica particles with an average particle size of 1.5μm (CV value: 88%)

D: Amorphous silica particles with an average particle size of 3μm (CV value: 45%)

E: Amorphous silica particles with an average particle size of 4.5μm (CV value: 35%)

F: True spherical cross-linked polymethyl methacrylate with an average particle diameter of 3μm (CV value: 32%)

G: Real spherical cross-linked polymethyl methacrylate with an average particle size of 1.5 μm (CV value: 23%)

H: 1-hydroxycyclohexyl phenyl ketone

[Test Example 1] (Measurement of Surface Shape)

For the surface of the writing-improving layer of the writing-improving films produced in the Examples and Comparative Examples, the optical interference type surface shape observation device (manufactured by Veeco, product name "WYKO-1100") was used for vertical scanning interferometric measurement Method (VSI mode), observe the observation image in the range of 91.2 μm×119.8 μm at 10 magnification. Then, the number of protrusions (large protrusions) with a height of 1 μm or more and 3 μm or less, and a maximum cross-sectional area of 10.2 μm ² or more, and a height of more than 0 μm (concavities and convexities of the noise level are excluded, specifically 0.2 μm or more) ), the number of protrusions (small protrusions) less than 1 μm are counted separately. The results are shown in Table 2. Furthermore, for reference, FIG. 2 shows an observation image of the surface of the writing-improving layer of the writing-improving film obtained in Example 1.

[Test Example 2] (Pen Sliding Test)

The writing-improving films produced in the examples and comparative examples were placed on a glass substrate with the writing-improving layer side facing upward. On the surface of the layer for improving writing feeling, use the stylus of a stylus pen (made by WACOM Corporation, product name "ACK-2003") with a tip diameter of 0.5mm with a hard felt core, under a pressure condition of 3.92N in the vertical The direction (the axis of the pen tip is perpendicular to the surface of the writing-improving layer) is to make contact, and move at a speed of 100mm/min in any direction parallel to the surface of the writing-improving film. Furthermore, the above-mentioned stylus is installed on a trolley dedicated to measurement, and by moving the trolley, the stylus is slid on the layer that improves the writing feeling.

The pen tip resistance during movement was measured using a universal testing machine (manufactured by Orientec, product name "Tensilon") to obtain a graph of movement distance (mm)-pen tip resistance (mN). Then, the obtained movement distance (mm)-pen tip resistance (mN) graph was Fourier transformed using software (manufactured by Microsoft Corporation, product name "Excel") to obtain a frequency (Hz)-amplitude (-) graph. From the frequency (Hz)-amplitude (-) graph, the average value, maximum value (maximum amplitude value), and number of crests (number of amplitudes) of the amplitude in the frequency range of 1 to 2 Hz are obtained. The results are shown in Table 2.

[Test Example 3] (Sensory Evaluation of Writing Feel)

The writing-improving films produced in the examples and comparative examples were placed on a glass substrate with the writing-improving layer side facing upward. For the surface of the layer that improves the writing feeling, the judges used a stylus pen (made by WACOM Corporation, product name "ACK-2003") with a hard felt core with a tip diameter of 0.5 mm to simulate a predetermined writing operation and evaluate the following writing feeling. The results are shown in Table 1. In addition, the evaluation of the writing feeling is based on five overlapping papers (manufactured by Kokuyo S&T, product name "CAMPUS NOTE ALINE, No-201A"), using a pencil (manufactured by Mitsubishi Pencil Co., product name "Mitsubishi Pencil Uni B" ") or pen (manufactured by ST DuPont, product name "LINE D 410674 Black lacquer & Palladium") as a reference.

(1) Floating pen tip

The drift of the pen tip, which is a feeling of writing, was evaluated based on the following criteria.

◎: The nib will not drift

○: The pen tip drifts slightly

×: The pen tip drifts excessively

(2) The card feel of the pen tip

The grip feeling of the pen tip, which is a writing feeling, was evaluated based on the following criteria.

◎: Will not notice the stickiness of the pen tip

○: There is a slight grip of the pen tip

×: The pen tip has excessive stickiness

(3) Vibration

The vibration as a feeling of writing was evaluated based on the following criteria.

◎: Appropriate vibration is transmitted to the hand

○: Vibration is transmitted to the hand but not enough

×: The vibration transmitted to the hand is too small or too large

(4) Scratching sound

The scratching sound, which is a feeling of writing, was evaluated based on the following criteria.

◎: A full rustling sound can be heard

○: A rustling sound can be heard, but it is a little small

△: A rustling sound can be heard vaguely

×: Can't hear the rustle

In addition, regarding the film for improving writing feeling of Example 4, the writing feeling as a pen is not good, but as a pen. Since it is a fountain pen, there is almost no writing sound. Therefore, in Example 4 in Table 2, the scratching sound is "-".

[Test Example 4] (Haze value‧Measurement of total light transmittance)

Using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product name "NDH-2000"), in compliance with JIS K7136: 2000, the haze value (%) and total value of the writing-improving films produced in the examples and comparative examples were measured Light transmittance (%). In addition, from the viewpoint of obtaining a suitable writing feeling, the haze value is preferably 7.5% or more, more preferably 9% or more, and particularly preferably 15% or more. In addition, from the viewpoint of not obtaining pen nib stickiness, etc., the haze value is preferably 30% or less. On the other hand, the total light transmittance is preferably over 80%. The results are shown in Table 1.

It can be seen from Table 2 that the film for improving writing feeling produced in the examples has excellent writing feeling using a stylus pen, and also excellent optical properties.

[Industrial availability]

The film for improving the writing feeling of the present invention can be used well as the outermost layer of a touch panel using a stylus pen.

1‧‧‧Film to improve writing

11‧‧‧Substrate film

12‧‧‧Improve the sense of writing

Claims (2)

A film for improving writing feeling, characterized in that it has: a layer for improving writing feeling. There are 8 or more and 30 or less in the area of 10925.76μm ² on the surface, the height is 1μm or more, 3μm or less, and the plane direction While the maximum cross-sectional area of the cross-section is 10.2 μm ² or more protrusions, there are 20 or more protrusions with a height exceeding 0 μm and less than 1 μm. In the writing-improving film described in the first item of the patent application, the writing-improving layer is a layer formed by curing a coating composition containing a curable component and fine particles.

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