Writing feeling improvement tablets

Abstract

The present invention provides a writing feel improving sheet that can well reproduce the writing feel when writing on paper with a writing tool. The writing feel improving sheet has a stylus contact surface that is contacted by a stylus, and the kinetic friction coefficient measured when the stylus is linearly slid on the stylus contact surface at a predetermined sliding speed is 0.13 or more and 0.35 or less when the sliding speed is 1.5 mm / s, 0.15 or more and 0.40 or less when the sliding speed is 20 mm / s, 0.18 or more and 0.45 or less when the sliding speed is 50 mm / s, and 0.18 or more and 0.47 or less when the sliding speed is 80 mm / s.

Description

Technical Field

[0001] The present invention relates to a writing feel improving sheet capable of improving the writing feel of a touch pen on a touch panel or the like. Background Art

[0002] In recent years, in various electronic devices, image display devices (touch panels) with position detection functions that serve as both display devices and input means have been widely used. In such a touch panel, in addition to using fingers for input, a stylus can also be used for input. If a stylus is used, more delicate and high-precision input operations can be performed than with fingers. However, the display module of the touch panel is usually hard. Therefore, the writing feel of using a stylus is different from the writing feel of using a writing tool on paper, and it is difficult to call it good.

[0003] In order to solve the problem of writing feel caused by using a stylus on a touch panel, a sheet for improving the writing feel (hereinafter sometimes referred to as a "writing feel improving sheet") is being studied by attaching it to the outermost surface of the touch panel. For example, Patent Documents 1 and 2 disclose a writing feel improving sheet that is adjusted in such a way that the friction coefficient when writing on the surface of the film using a stylus is within a specified range. In particular, Patent Document 1 discloses and specifies the correlation between the static friction coefficient and the dynamic friction coefficient when the stylus is moved at a speed of 5 cm / second. In addition, Patent Document 2 discloses and specifies the correlation between the static friction coefficient and the dynamic friction coefficient when the stylus is moved at a speed of 100 mm / second.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6156647

[0007] Patent Document 2: Japanese Patent No. 5774954 Summary of the invention

[0008] Technical Problems to be Solved by the Invention

[0009] However, the inventions disclosed in Patent Documents 1 and 2 do not fully achieve the writing feel when writing on paper using a writing tool (especially a ballpoint pen). Therefore, a writing feel improving sheet that can better reproduce the writing feel when writing on paper using a writing tool is sought to be developed.

[0010] The present invention has been made in view of such actual circumstances, and an object of the present invention is to provide a writing feel-improving sheet that can well reproduce the writing feel when writing on paper using a writing instrument.

[0011] Technical means to solve technical problems

[0012] In order to achieve the above-mentioned object, first, the present invention provides a writing feel improving sheet, which is a writing feel improving sheet having a stylus pen contact surface with which a stylus pen contacts, characterized in that, after the tip of a stylus pen having a tip with a diameter of 0.5 mm is brought into contact with the stylus pen contact surface, a load of 200 g is applied to the stylus pen, and while the angle between the stylus pen and the stylus pen contact surface is maintained at 45°, the stylus pen is linearly slid at a specified sliding speed, and the dynamic friction coefficient measured at this time is 0.13 or more and 0.35 or less when the sliding speed is 1.5 mm / s, 0.15 or more and 0.40 or less when the sliding speed is 20 mm / s, 0.18 or more and 0.45 or less when the sliding speed is 50 mm / s, and 0.18 or more and 0.47 or less when the sliding speed is 80 mm / s (Invention 1).

[0013] By making the dynamic friction coefficient of the writing feel improving sheet of the above-mentioned invention (Invention 1) measured at the four sliding speeds as mentioned above fall within the above-mentioned ranges, the vibration feeling of the writing tool when writing on paper with a writing tool (especially a ballpoint pen) at various writing speeds can be well reproduced, thereby well reproducing the writing feel when writing on paper with a writing tool.

[0014] Second, the present invention provides a writing feel improving sheet, which is a writing feel improving sheet having a stylus contact surface with which a stylus pen contacts, characterized in that, after the tip of a stylus pen having a tip with a diameter of 0.5 mm is brought into contact with the stylus contact surface, a load of 200 g is applied to the stylus pen, and while the angle between the stylus pen and the stylus contact surface is maintained at 45°, the stylus pen is linearly slid at a specified sliding speed. For the dynamic friction coefficient measured at this time, when the measurement result is plotted on a coordinate plane with the sliding speed as the horizontal axis (unit: mm / second) and the dynamic friction coefficient as the vertical axis, the slope of the line segment connecting the coordinate with the sliding speed of 1.5 mm / second and the coordinate with the sliding speed of 50 mm / second is greater than 0.0006 and less than 0.0072 (Invention 2).

[0015] By making the above-mentioned slope of the writing feel improving sheet of the above-mentioned invention (Invention 2) fall within the above-mentioned range, the vibration feeling of the writing tool when writing on paper with a writing tool (especially a ballpoint pen) at various writing speeds can be well reproduced, thereby well reproducing the writing feel when writing on paper with a writing tool.

[0016] Third, the present invention provides a writing feel improving sheet having a stylus contact surface with which a stylus pen contacts, characterized in that after the tip of a stylus pen having a tip of 0.5 mm in diameter is brought into contact with the stylus contact surface, a load of 200 g is applied to the stylus pen, and while the angle between the stylus pen and the stylus contact surface is maintained at 45°, the stylus pen is linearly slid at a prescribed sliding speed. For the dynamic friction coefficient measured at this time, when the measurement result is plotted on a coordinate plane with the sliding speed as the horizontal axis (X axis) (unit: mm / second) and the dynamic friction coefficient as the vertical axis (Y axis), the coordinates of the four points of the sliding speed of 1.5 mm / s, the sliding speed of 20 mm / s, the sliding speed of 50 mm / s, and the sliding speed of 80 mm / s are polynomially approximated to obtain an approximate curve that satisfies the following equations (1) to (4):

[0017] Y=aX 2 +bX+c···(1);

[0018] -5×10 -5 ≤a≤-5×10 -6 ···(2);

[0019] 0.0001≤b≤0.008···(3);

[0020] 0.11≤c≤0.31···(4)(Invention 3).

[0021] By making the writing feel improving sheet of the above-mentioned invention (Invention 3) display the above-mentioned approximate curve, the vibration feeling of the writing tool when writing on paper with a writing tool (especially a ballpoint pen) at various writing speeds can be well reproduced, thereby well reproducing the writing feel when writing on paper with a writing tool.

[0022] In the above inventions (Inventions 1 to 3), it is preferred that: there is a writing feel improving layer and a substrate provided on one surface side of the writing feel improving layer, and the surface of the writing feel improving layer opposite to the substrate is the stylus pen contact surface (Invention 4).

[0023] Effects of the Invention

[0024] The writing feeling improving sheet of the present invention can well reproduce the writing feeling when writing on paper with a writing instrument. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described.

[0026] The writing feel improving sheet of one embodiment of the present invention has a stylus contact surface that is contacted by a stylus. Both sides of the writing feel improving sheet of this embodiment can be stylus contact surfaces, but usually only one side of the writing feel improving sheet is the stylus contact surface, and the other side is a surface for bonding to a touch panel or the like.

[0027] 1. Physical properties of writing feel improving sheet

[0028] (1) Dynamic friction coefficient

[0029] For the writing feel improving sheet of the present embodiment, after the pen tip of a stylus pen having a pen tip of 0.5 mm in diameter is brought into contact with the stylus pen contact surface of the writing feel improving sheet of the present embodiment, a load of 200 g is applied to the stylus pen, and the stylus pen is linearly slid at a predetermined sliding speed while maintaining the angle between the stylus pen and the stylus pen contact surface at 45°, the dynamic friction coefficient measured at this time preferably satisfies the following conditions. That is, preferably, the dynamic friction coefficient at the sliding speed of 1.5 mm / s is 0.13 or more and 0.35 or less, the dynamic friction coefficient at the sliding speed of 20 mm / s is 0.15 or more and 0.40 or less, the dynamic friction coefficient at the sliding speed of 50 mm / s is 0.18 or more and 0.45 or less, and the dynamic friction coefficient at the sliding speed of 80 mm / s is 0.18 or more and 0.47 or less.

[0030] When studying the feeling of writing, the inventors of the present application focused on the fact that the writing speed when writing on paper with a writing implement will change depending on the writer or the content of the writing. For example, there is a tendency that the writing speed is relatively fast when simply taking notes, and on the other hand, the writing speed is relatively slow when practicing writing Chinese characters. Moreover, the inventors of the present application conducted further detailed research and found that the coefficient of kinetic friction when writing on paper with a writing implement changes depending on the writing speed. For example, it was found that when writing on paper with a ballpoint pen, there is a tendency that the slower the writing speed, the smaller the coefficient of kinetic friction, and there is a tendency that the faster the writing speed, the larger the coefficient of kinetic friction. It cannot be said that the previous writing feeling improvement sheets fully reproduce this change in the coefficient of kinetic friction that depends on the writing speed.

[0031] On the other hand, since the writing feel improving sheet of the present embodiment satisfies the above-mentioned coefficient of dynamic friction at the four sliding speeds as described above, when a stylus is used on a touch panel to which the writing feel improving sheet is attached, the vibration sense transmitted to the hand holding the stylus is very close to the vibration sense obtained when writing on paper with a writing tool (especially a ballpoint pen). In particular, the writing feel improving sheet of the present embodiment can well reproduce the change in the coefficient of dynamic friction that depends on the writing speed. As a result, the writing feel improving sheet of the present embodiment can achieve an unprecedented excellent writing feel.

[0032] From the perspective of achieving a better writing feel, the dynamic friction coefficient at a sliding speed of 1.5 mm / s is preferably 0.17 or more, particularly preferably 0.20 or more. In addition, the dynamic friction coefficient is preferably 0.30 or less, particularly preferably 0.29 or less.

[0033] In addition, from the same perspective, the dynamic friction coefficient at a sliding speed of 20 mm / s is preferably 0.20 or more, particularly preferably 0.25 or more. In addition, the dynamic friction coefficient is preferably 0.36 or less, particularly preferably 0.33 or less.

[0034] From the same perspective, the coefficient of kinetic friction at a sliding speed of 50 mm / s is preferably 0.25 or more, particularly preferably 0.30 or more. In addition, the coefficient of kinetic friction is preferably 0.40 or less, particularly preferably 0.37 or less.

[0035] From the same perspective, the dynamic friction coefficient at a sliding speed of 80 mm / s is preferably 0.25 or more, particularly preferably 0.30 or more. In addition, the dynamic friction coefficient is preferably 0.40 or less, particularly preferably 0.37 or less.

[0036] The details of the method for measuring the above-mentioned dynamic friction coefficient are shown in the description of the test examples described later.

[0037] (2) Slope of the coefficient of kinetic friction

[0038] The writing feel-improving sheet according to the present embodiment preferably satisfies the following conditions regarding the “slope” regarding the dynamic friction coefficient measured as described above.

[0039] That is, the writing feel improving sheet of the present embodiment is also preferably: after the pen tip of a stylus having a pen tip with a diameter of 0.5 mm is brought into contact with the stylus contact surface of the writing feel improving sheet of the present embodiment, a load of 200 g is applied to the stylus, and while maintaining the angle between the stylus and the stylus contact surface at 45°, the stylus is linearly slid at a specified sliding speed. For the dynamic friction coefficient measured at this time, when the measurement result is plotted on a coordinate plane with the sliding speed as the horizontal axis (unit: mm / second) and the dynamic friction coefficient as the vertical axis, the slope of the line segment connecting the coordinate with the sliding speed of 1.5 mm / second and the coordinate with the sliding speed of 50 mm / second is greater than 0.0006 and less than 0.0072.

[0040] Generally, a sliding speed of 1.5 mm / second is equivalent to a writing speed when writing quite slowly, and a sliding speed of 50 mm / second is equivalent to a writing speed when writing quickly. In the writing feeling improving sheet of the present embodiment, since the above-mentioned slope is in the above-mentioned range, the dynamic friction coefficient increases as the sliding speed increases from a low speed to a high speed. Thus, the relationship between the writing speed and the dynamic friction coefficient when writing on paper using a writing tool can be well reproduced (i.e., the dynamic friction coefficient is small when writing slowly and the dynamic friction coefficient is large when writing quickly), and an unprecedented excellent writing feeling can be achieved.

[0041] From the perspective of achieving a better writing feel, the above slope is preferably 0.0008 or more, more preferably 0.0010 or more, particularly preferably 0.0011 or more, and further preferably 0.0013 or more. In addition, from the same perspective, the above slope is preferably 0.0050 or less, more preferably 0.0030 or less, particularly preferably 0.0026 or less, and further preferably 0.0020 or less.

[0042] In addition, when a linear equation is used to represent a line segment connecting a coordinate at a sliding speed of 1.5 mm / sec and a coordinate at a sliding speed of 50 mm / sec, the intercept of the linear equation is preferably 0.10 or more, particularly preferably 0.16 or more, and further preferably 0.20 or more. In addition, the intercept is preferably 0.35 or less, particularly preferably 0.30 or less, and further preferably 0.28 or less. By making the intercept within the above range, it is easier to reproduce the vibration feeling of the writing tool when writing on paper with the writing tool.

[0043] In addition, from the perspective of easily adjusting the slope of the line segment connecting the coordinates at a sliding speed of 1.5 mm / second and the coordinates at a sliding speed of 50 mm / second to the above range, in the coordinate plane obtained as described above, the slope of the line segment connecting the coordinates at a sliding speed of 1.5 mm / second and the coordinates at a sliding speed of 20 mm / second is preferably 0.0010 or more, particularly preferably 0.0013 or more, and further preferably 0.0018 or more. In addition, from the same perspective, the slope of the line segment connecting the coordinates at a sliding speed of 1.5 mm / second and the coordinates at a sliding speed of 20 mm / second is preferably 0.0090 or less, particularly preferably 0.0050 or less, and further preferably 0.0040 or less.

[0044] In addition, from the perspective of easily adjusting the slope of the line segment connecting the coordinates at a sliding speed of 1.5 mm / second and the coordinates at a sliding speed of 50 mm / second to the above range, in the coordinate plane obtained as described above, the slope of the line segment connecting the coordinates at a sliding speed of 1.5 mm / second and the coordinates at a sliding speed of 80 mm / second is preferably 0.0005 or more, particularly preferably 0.0007 or more, and further preferably 0.0009 or more. In addition, from the same perspective, the slope of the line segment connecting the coordinates at a sliding speed of 1.5 mm / second and the coordinates at a sliding speed of 80 mm / second is preferably 0.0030 or less, particularly preferably 0.0020 or less, and further preferably 0.0015 or less.

[0045] (3) Approximate curve of dynamic friction coefficient

[0046] In the writing feel-improving sheet of the present embodiment, it is also preferred that the dynamic friction coefficient measured as described above satisfies the following conditions regarding the “approximate curve”.

[0047] That is, the writing feel improving sheet of the present embodiment is also preferably: after the pen tip of a stylus having a pen tip with a diameter of 0.5 mm is brought into contact with the stylus contact surface of the writing feel improving sheet of the present embodiment, a load of 200 g is applied to the stylus, and while the angle between the stylus and the stylus contact surface is maintained at 45°, the stylus is linearly slid at a predetermined sliding speed. For the dynamic friction coefficient measured at this time, when the measurement result is plotted on a coordinate plane with the sliding speed as the horizontal axis (X axis) (unit: mm / sec) and the dynamic friction coefficient as the vertical axis (Y axis), the coordinates of the four points, namely, the coordinates at the sliding speed of 1.5 mm / s, the coordinates at the sliding speed of 20 mm / s, the coordinates at the sliding speed of 50 mm / s, and the coordinates at the sliding speed of 80 mm / s, are polynomially approximated to obtain an approximate curve that satisfies the following equations (1) to (4):

[0048] Y=aX 2 +bX+c···(1);

[0049] -5×10 -5 ≤a≤-5×10 -6 ···(2);

[0050] 0.0001≤b≤0.008···(3);

[0051] 0.11≤c≤0.31···(4).

[0052] Since the approximate curve of the writing feel improving sheet of this embodiment is as described above, it is easy to make the change of the dynamic friction coefficient corresponding to the change of the sliding speed consistent with the situation of writing on paper using a writing tool. As a result, the relationship between the writing speed and the dynamic friction coefficient when writing on paper using a writing tool can be well reproduced, and an unprecedented excellent writing feel can be achieved.

[0053] From this perspective, the value of a in the above formula (2) is preferably -4×10 -5 Above, especially preferably -3×10 -5 In addition, the value of a in the above formula (2) is preferably -8×10 -6 Below, particularly preferably -1×10 -5 the following.

[0054] From the same viewpoint, the value of b in the above formula (3) is preferably 0.0010 or more, and particularly preferably 0.0020 or more. The value of b in the above formula (3) is preferably 0.0050 or less, and particularly preferably 0.0035 or less.

[0055] Furthermore, from the same viewpoint, the value of c in the above formula (4) is preferably 0.16 or more, and particularly preferably 0.20 or more. In addition, the value of c in the above formula (4) is preferably 0.29 or less, and particularly preferably 0.28 or less.

[0056] (4) Optical properties

[0057] The haze value of the writing feel improving sheet of the present embodiment is not particularly limited, but is preferably 0.1% or more, more preferably 0.5% or more, and particularly preferably 10% or more from the perspective of obtaining sufficient anti-glare properties. On the other hand, the haze value is preferably 95% or less, particularly preferably 50% or less, and further preferably 20% or less. By making the haze value 95% or less, the transparency of the writing feel improving sheet of the present embodiment becomes higher. In addition, the haze value is a value measured in accordance with JIS K7136:2000, and the detailed measurement method is shown in the description of the test example described later.

[0058] The total light transmittance of the writing feel improving sheet of the present embodiment is preferably 70% or more, particularly preferably 80% or more, and further preferably 88% or more. By making the total light transmittance 70% or more, the transparency of the writing feel improving sheet of the present embodiment becomes higher. On the other hand, there is no particular restriction on the upper limit of the total light transmittance, for example, it is preferably 100% or less, particularly preferably 96% or less, and further preferably 92% or less. In addition, the total light transmittance is a value measured in accordance with JIS K7361-1:1997, and the detailed measurement method is shown in the description of the test example described later.

[0059] (5) Scratch resistance

[0060] For the writing feel improving sheet of the present embodiment, #0000 steel wool was used at 250 g / cm 2 The stylus contact surface is rubbed back and forth 10 times at a speed of 10 cm with a load of , and the number of scratches produced at this time is preferably 10 or less, particularly preferably 5 or less, and further preferably 0. Therefore, the stylus contact surface of the writing feel improvement sheet of the present embodiment can exert good hard coating properties and excellent abrasion resistance. In addition, when the writing feel improvement sheet of the present embodiment has a hard coating layer as a writing feel improvement layer as described later, it is easy to achieve abrasion resistance based on the evaluation of such steel wool hardness. In addition, the detailed determination method of the above-mentioned abrasion resistance is shown in the description of the test example described later.

[0061] 2. Layer structure of the writing feel improving sheet

[0062] The layer structure of the writing feel improving sheet of this embodiment is not particularly limited as long as the stylus pen contact surface satisfies the above-mentioned dynamic friction coefficient at each sliding speed and the stylus pen contact surface is applicable to a touch panel using a stylus pen.

[0063] From the perspective of being able to easily achieve the above-mentioned coefficient of kinetic friction at each sliding speed and being able to easily adjust other physical properties, the writing feel improving sheet of this embodiment preferably includes a writing feel improving layer and a substrate provided on one side of the writing feel improving layer. When having such a layer structure, the surface of the writing feel improving layer opposite to the substrate is preferably a stylus contact surface.

[0064] (1) Base material

[0065] The substrate may be appropriately selected from substrates suitable for touch panels using a stylus pen. For example, a plastic film, a glass plate, etc. may be used as the substrate, but a plastic film is preferably used from the perspective of good affinity with the writing feel improving layer.

[0066] As the plastic film, for example, polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin films such as polyethylene film and polypropylene film; celluloid, cellulose diacetate film, cellulose triacetate film, cellulose butyl acetate film (acetyl cellulose 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, polyetherimide 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, and other plastic films, or laminated films of these films can be listed. Among them, from the perspective of easily obtaining the desired optical properties, it is preferred to use a polyester film, and it is particularly preferred to use polyethylene terephthalate.

[0067] In addition, for the purpose of improving the adhesion between the substrate and the layer (writing feeling improvement layer, adhesive layer described later, etc.) disposed on the surface thereof, an easy-adhesive layer formed by primer treatment, etc., or a surface treatment layer obtained by oxidation method, embossing method, etc., may be provided on one side or both sides of the substrate as required. Examples of the oxidation method include corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone and ultraviolet treatment, etc. In addition, examples of the embossing method include sandblasting method, solvent treatment method, etc.

[0068] In addition, in this specification, the above-mentioned easy-adhesive layer or surface-treated layer is defined as a part of the substrate. Therefore, for example, even if it is assumed that the writing feel improving layer is directly laminated on the substrate to form a writing feel improving sheet, the possibility that the above-mentioned easy-adhesive layer or surface-treated layer exists in the substrate in such a writing feel improving sheet is not excluded.

[0069] The thickness of the substrate is preferably 20 μm or more, more preferably 80 μm or more, particularly preferably 100 μm or more, and further preferably 120 μm or more. By making the lower limit of the thickness of the substrate the above range, it is easy to exert sufficient pencil hardness, and even if various layers (such as adhesive layers) are provided on the side of the substrate opposite to the writing feeling improvement layer, the writing feeling of the writing feeling improvement layer is not easily affected by such a layer. In addition, the thickness of the substrate is preferably 300 μm or less, more preferably 200 μm or less, and particularly preferably 150 μm or less. By making the upper limit of the thickness of the substrate the above range, the writing feeling improvement sheet of the present embodiment has moderate softness and is easy to operate.

[0070] (2) Writing feel improvement layer

[0071] The material used to form the writing feel improving layer is not particularly limited as long as it can achieve the above-mentioned dynamic friction coefficient at each sliding speed. In addition, the writing feel improving layer can be a hard coating layer with hard coating properties, in which case the stylus contact surface is likely to have good scratch resistance.

[0072] The writing feel-improving layer is preferably formed by curing the coating composition described below. It is particularly preferred that the coating composition contains a curable component and a surface conditioner.

[0073] (2-1) Curable Component

[0074] The curable component is a component that is cured by a trigger such as active energy rays or heat, and examples thereof include active energy ray-curable components and thermosetting components. In the present embodiment, active energy ray-curable components are preferably used from the perspective of the hardness of the writing feel improving layer formed or the heat resistance of the substrate (plastic film).

[0075] As the active energy ray-curable component, it is preferable to use a component that can be cured by irradiation with active energy rays to exhibit a predetermined hardness and achieve the above-mentioned physical properties.

[0076] As specific active energy ray-curable components, multifunctional (meth)acrylate monomers, (meth)acrylate prepolymers, active energy ray-curable polymers, etc. can be listed, among which multifunctional (meth)acrylate monomers and / or (meth)acrylate prepolymers are preferred. Multifunctional (meth)acrylate monomers and (meth)acrylate prepolymers can be used alone or both can be used at the same time. In addition, in this specification, (meth)acrylate refers to both acrylate and methacrylate. Other similar terms are also the same.

[0077] Examples of the polyfunctional (meth)acrylate monomer include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, dicyclopentyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, allylated cyclohexyl di(meth)acrylate, isocyanurate di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. The present invention also includes polyfunctional (meth)acrylates such as (meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, propionic acid-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. These polyfunctional (meth)acrylate monomers may be used alone or in combination of two or more.

[0078] On the other hand, as (meth)acrylate prepolymers, for example, urethane acrylate, polyester acrylate, epoxy acrylate, polyol acrylate, etc. can be cited. Among them, urethane acrylate prepolymers are preferably used from the perspective of easily achieving the above-mentioned dynamic friction coefficient at each sliding speed.

[0079] Examples of the urethane acrylate prepolymer include a reaction product obtained by esterifying a hydroxyl group of a polyurethane pre-oligomer obtained from a polyether polyol or a polyester polyol and a polyisocyanate using (meth)acrylic acid; a reaction product obtained by reacting a hydroxyl-containing (meth)acrylic acid with an isocyanate-terminated polyurethane oligomer obtained by reacting a polyether polyol or a polyester polyol with a polyisocyanate; and the like.

[0080] (2-2) Surface Conditioner

[0081] By making the coating composition contain a surface conditioner, it is possible to suppress the occurrence of streaky defects or unevenness in the formed writing feel improving layer. As a result, the film thickness becomes uniform, the writing feel improving sheet exhibits a more excellent appearance, and it is easy to have the desired optical properties (haze value and total light transmittance, etc.). In addition, since the surface conditioner is easily exposed on the surface of the writing feel improving layer of the writing feel improving sheet, the smoothness of the writing feel improving layer can be adjusted, and the above-mentioned dynamic friction coefficient at each sliding speed can be easily achieved.

[0082] Examples of the surface conditioner include fluorine-based, silicone-based, acrylic-based, and vinyl-based surface conditioners. Among them, from the perspective of easily adjusting the smoothness of the writing feel improving layer, it is preferred to use at least one of the fluorine-based and silicone-based surface conditioners. In addition, the surface conditioner may be used alone or in combination of two or more.

[0083] As the fluorine-based surface conditioning agent, preferably a compound having a perfluoroalkyl group or a fluorinated alkenyl group on the main chain or the side chain can be listed. As commercially available products, preferably BYK-340 manufactured by BYK Japan KK., FTERGENT 650A manufactured by Neos Corporation, Megafac RS-75 manufactured by DIC Corporation, V-8FM manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD., etc. can be listed, but it is not limited thereto. As the silicone-based surface conditioning agent, preferably polydimethylsiloxane or modified polydimethylsiloxane, particularly preferably polydimethylsiloxane.

[0084] Relative to 100 parts by mass of curable components, the content of the surface conditioning agent in the coating composition is preferably 0.01 parts by mass or more, particularly preferably 0.1 parts by mass or more, and more preferably 0.2 parts by mass or more. In addition, relative to 100 parts by mass of curable components, the content of the surface conditioning agent in the coating composition is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 3 parts by mass or less, and more preferably 1 part by mass or less. By making the content of the surface conditioning agent the above range, the appearance of the writing feeling improvement sheet can be effectively improved. In addition, it is easy to adjust the optical properties (haze value and total light transmittance, etc.) to the above range. Further, the writing feeling improvement layer is easy to achieve the above-mentioned coefficient of kinetic friction at each sliding speed.

[0085] (2-3) Microparticles

[0086] By containing fine particles in the coating composition, the surface of the formed writing feel improving layer becomes a moderately rough surface, the haze value can be easily adjusted, and the desired anti-glare property can be easily exhibited.

[0087] In addition, the average particle size of the microparticles is larger than the silica nanoparticles described later. For example, the average particle size of the microparticles is preferably 1 μm or more, particularly preferably 2 μm or more, and further preferably 3 μm or more. In addition, the average particle size of the microparticles is preferably 20 μm or less, particularly preferably 14 μm or less, and further preferably 8 μm or less. By making the average particle size of the microparticles within the above range, it is easier to adjust the haze value.

[0088] In addition, the coefficient of variation (CV value) of the particle size represented by the following formula of the above-mentioned particles is preferably 3% or more, particularly preferably 8% or more. Further, the coefficient of variation (CV value) of the particle size is preferably 70% or less, particularly preferably 45% or less, and further preferably 25% or less. By making the CV value of the above-mentioned particles within the above-mentioned range, it is easier to adjust the concavo-convex shape of the surface, it is easy to achieve the above-mentioned coefficient of kinetic friction at each sliding speed, and it is easier to adjust the haze value.

[0089] Coefficient of variation of particle size (CV value) = (standard deviation particle size / average particle size) × 100

[0090] The average particle size and coefficient of variation (CV value) of the particle size of the fine particles are values ​​measured using a laser diffraction scattering particle size distribution analyzer using a few drops of a 5 mass % dispersion prepared using methyl ethyl ketone as a dispersion medium as a sample.

[0091] The above-mentioned particles can be organic particles, inorganic particles, or resin particles having both inorganic and organic properties. From the perspective of easily achieving the above-mentioned dynamic friction coefficient at each sliding speed and easier adjustment of the haze value, organic particles or resin particles having both inorganic and organic properties are preferred.

[0092] Examples of organic particles include acrylic resin particles (e.g., polymethyl methacrylate particles, etc.), silicone particles, melamine resin particles, acrylic-styrene copolymer particles, polycarbonate particles, polyethylene particles, polystyrene particles, benzoguanamine resin particles, etc. These resins may also be cross-linked. Among them, acrylic resin particles and silicone particles are preferred from the perspective of easier adjustment of the haze value.

[0093] Examples of the inorganic fine particles include fine particles made of silicon dioxide, aluminum oxide, titanium dioxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like.

[0094] As the resin fine particles having both inorganic and organic properties, silicone fine particles (for example, Tospearl series manufactured by Momentive Performance Materials Japan Inc.) are particularly preferred.

[0095] The above-mentioned fine particles may be used alone or in combination of two or more.

[0096] The above-mentioned particles can be particles that have been subjected to the desired surface modification. In addition, the shape of the particles can be a regular shape such as a sphere, or an irregular shape with no specified shape. From the perspective of being easy to achieve the above-mentioned coefficient of kinetic friction at each sliding speed and being easier to adjust the haze value, a regular shape is preferred, and a sphere is particularly preferred.

[0097] Relative to 100 parts by mass of curable components, the content of the microparticles in the coating composition is preferably more than 0.01 parts by mass, more preferably more than 0.1 parts by mass, particularly preferably more than 1 parts by mass, and further preferably more than 3 parts by mass. In addition, relative to 100 parts by mass of curable components, the content of the microparticles in the coating composition is preferably less than 50 parts by mass, particularly preferably less than 30 parts by mass, and further preferably less than 10 parts by mass. By making the content of microparticles the above-mentioned range, it is easy to play anti-glare, and it is easy to reach the dynamic friction coefficient under each sliding speed mentioned above.

[0098] (2-4) Other ingredients

[0099] In addition to the above-mentioned components, the coating composition in the present embodiment may also contain various additives. As various additives, for example, photopolymerization initiator, silicon dioxide nanoparticles, ultraviolet absorber, antioxidant, light stabilizer, antistatic agent, silane coupling agent, anti-aging agent, thermal polymerization inhibitor, colorant, surfactant, storage stabilizer, plasticizer, lubricant, defoamer, organic filling material, wettability improver, coating surface improver, etc. can be listed.

[0100] Examples of the photopolymerization initiator 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-phenylpropane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 4- (2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzil dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, etc. These photopolymerization initiators may be used alone or in combination of two or more.

[0101] The content of the photopolymerization initiator in the coating composition is preferably 1 part by mass or more, particularly preferably 2 parts by mass or more, relative to 100 parts by mass of the curable component. In addition, the content of the photopolymerization initiator in the coating composition is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, relative to 100 parts by mass of the curable component.

[0102] (2-5)Thickness

[0103] The thickness of the writing feel improving layer is preferably 0.1 μm or more, particularly preferably 1 μm or more, and further preferably 2 μm or more. In addition, the thickness of the writing feel improving layer is preferably 30 μm or less, more preferably 20 μm or less, and particularly preferably 10 μm or less. By setting the thickness of the writing feel improving layer to be within the above range, the writing feel improving sheet of the present embodiment can easily achieve the above-mentioned dynamic friction coefficient at each sliding speed.

[0104] (3) Other components

[0105] As long as the writing feel improving layer is the outermost surface, the writing feel improving sheet of this embodiment may further have other layers. For example, an adhesive layer may be formed on the surface of the substrate opposite to the writing feel improving layer, and a release sheet may be further laminated on the adhesive layer.

[0106] As the adhesive constituting the adhesive layer, adhesives commonly used for optical applications can be used, for example, acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among them, acrylic adhesives are preferred because they exhibit the desired adhesiveness, optical properties, and excellent durability.

[0107] The thickness of the adhesive layer is preferably 5 μm or more, particularly preferably 10 μm or more, and further preferably 20 μm or more. In addition, the thickness of the adhesive layer is preferably 300 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less.

[0108] As the release sheet, for example, polyethylene film, polypropylene film, polybutylene 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-(methyl) acrylic acid copolymer film, ethylene-(methyl) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, liquid crystal polymer film, etc. can be used. In addition, crosslinked films of these films can also be used. Further, laminated films of these films can also be used.

[0109] The release surface (surface in contact with the adhesive layer) of the release sheet is preferably subjected to a release treatment. Examples of release agents used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

[0110] The thickness of the release sheet is not particularly limited, but is generally about 20 to 150 μm.

[0111] 3. Method for producing writing feel improving sheet

[0112] As long as the writing feel improving sheet can achieve the above-mentioned dynamic friction coefficient at each sliding speed, the method for producing the writing feel improving sheet of the present embodiment is not particularly limited. For example, the writing feel improving sheet is preferably produced by applying a coating liquid containing the above-mentioned coating composition and a desired solvent on a substrate and curing the coating liquid to form a writing feel improving layer.

[0113] The solvent can be used for improving coating properties, adjusting viscosity, adjusting solid content concentration, and the like, and any solvent can be used without particular limitation as long as it can dissolve curable components and the like and disperse fine particles and the like.

[0114] Specific examples of the solvent 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), and propylene glycol monomethyl ether; aromatic hydrocarbons such as benzene, toluene, and xylene; amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone, and the like.

[0115] The coating liquid of the coating composition can be applied by any conventional method, such as rod coating, knife coating, roll coating, blade coating, die coating, or 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.

[0116] When the coating composition has active energy ray curing properties, the coating composition is cured by irradiating the coating film of the coating composition with active energy rays such as ultraviolet rays, electron beams, etc. The ultraviolet irradiation can be performed by a high-pressure mercury lamp, a fusion H lamp (FUSION H LAMP), a xenon lamp, etc. The irradiation amount of ultraviolet rays is preferably 50 to 1000 mW / cm 2 , light intensity is 50~1000mJ / cm 2 The illumination is preferably 100 to 500 mW / cm 2, light intensity is 100~500mJ / cm 2 On the other hand, electron beam irradiation can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

[0117] 4. Use of writing feeling improvement tablets

[0118] The writing feel improving sheet of this embodiment can be used as the outermost sheet constituting a touch panel (image display device with position detection function) using a stylus pen. Specifically, it is preferably laminated on a covering material of a touch panel having a display module such as a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescent (organic EL) module, or a contact sensor. It is preferably attached via the above-mentioned adhesive layer, thereby laminating the writing feel improving sheet on the covering material.

[0119] In addition, the stylus pen used for the writing feel improving sheet of this embodiment is not particularly limited, and a conventionally known stylus pen can be used. For example, a stylus pen having a polyacetal pen tip, a stylus pen having a hard felt pen tip, a stylus pen having an elastic pen tip, etc. can be used as the stylus pen. Among them, from the perspective of easily satisfying the above-mentioned dynamic friction coefficient at each sliding speed, it is preferable to use a stylus pen having an elastic pen tip.

[0120] In addition, the shape of the pen tip of the stylus pen used for the writing feel improving sheet of this embodiment is not particularly limited, and can be appropriately selected from a disc-shaped pen tip, a round pen tip, a polygonal pen tip, etc. From the perspective of obtaining a vibration feeling when writing with a ballpoint pen, a round pen tip is preferred. When the shape of the pen tip of the stylus pen is round, the diameter of the pen tip is preferably 0.1 mm or more, particularly preferably 0.2 mm or more, and more preferably 0.3 mm or more. In addition, the above diameter is preferably 5 mm or less, particularly preferably 2 mm or less, and more preferably 1 mm or less.

[0121] By making the writing feel improving sheet of this embodiment satisfy the above-mentioned dynamic friction coefficient at each sliding speed, the vibration feeling of the writing tool (especially a ballpoint pen) when writing on paper can be well reproduced. Thus, the writing feeling when writing on paper with a writing tool can be well reproduced.

[0122] 5. Another Implementation Method

[0123] The writing feeling improving sheet according to the present embodiment described above may constitute another embodiment of the present invention together with other elements.

[0124] For example, another embodiment of the present invention may be a set of the above-mentioned writing feel improving sheet and a stylus pen used for the writing feel improving sheet. Examples of the stylus pen in the set include a stylus pen having a polyacetal nib, a stylus pen having a hard felt nib, a stylus pen having an elastic nib, etc. However, from the perspective of easily achieving an excellent writing feel, a stylus pen having an elastic nib is preferably used.

[0125] Another embodiment of the present invention may be an image display device (especially a touch panel) having the above-mentioned writing feel improving sheet on its outermost surface.

[0126] 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 also covers all design changes and equivalents within the technical scope of the present invention.

[0127] For example, another layer may be present between the base material and the writing feel improving layer of the writing feel improving sheet according to the present embodiment.

[0128] Example

[0129] Hereinafter, 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.

[0130] [Preparation Example]

[0131] The materials described in Table 1 were mixed in the composition shown in Table 2 to obtain coating compositions C1 to C7. The blending ratios shown in Table 2 are ratios based on solid content conversion values. Furthermore, the obtained coating compositions were diluted with propylene glycol monomethyl ether to obtain coating solutions of coating compositions C1 to C7.

[0132] [Example 1]

[0133] (1) Formation of a writing feel improving layer

[0134] The coating liquid of the coating composition C1 obtained in the above preparation example was applied to one side of a polyethylene terephthalate (PET) film (manufactured by Toray Industries, Inc., product name "LUMIRROR U48", thickness 125 μm) having an adhesive layer on both sides as a substrate using a Myler rod to form a coating film, which was then heated in an oven at 70° C. for 1 minute to dry the coating film.

[0135] Next, in a nitrogen atmosphere, ultraviolet rays were irradiated using an ultraviolet irradiation device (manufactured by GS Yuasa International Ltd., product name "Nitrogen-purged small conveyor-type UV irradiation device (Nitrogen Purge Small Conveyor-type UV irradiation device) CSN2-40") under the following conditions to cure the above-mentioned coating film and form a writing feel improvement layer with a thickness of 10 μm.

[0136] [Ultraviolet irradiation conditions]

[0137] Light source: high pressure mercury lamp

[0138] Lamp power: 1.4kW

[0139] Conveyor belt speed: 1.2m / min

[0140] Illuminance: 100mW / cm 2

[0141] Light intensity: 240mJ / cm 2

[0142] Oxygen concentration: less than 1%

[0143] (2) Formation of Adhesive Layer

[0144] A (meth)acrylate copolymer was prepared by copolymerizing 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid by solution polymerization. The molecular weight of the (meth)acrylate copolymer was measured by the method described below, and the weight average molecular weight (Mw) was 1.5 million.

[0145] 99.8 parts by mass (solid content conversion value; the same applies hereinafter) of the obtained (meth)acrylate copolymer and 0.2 parts by mass of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane as a crosslinking agent were mixed and stirred thoroughly, and diluted with toluene to obtain a coating liquid of an adhesive composition.

[0146] Next, the coating liquid of the adhesive composition obtained as described above was applied onto a release sheet (manufactured by LINTEC CORPORATION, product name) using an applicator.

[0147] The coating film was formed on the release surface of a polyethylene terephthalate film (SP-PET381031) having a thickness of 38 μm and a silicone release agent layer formed on one side of the release sheet. The coating film was then dried by heating at 100° C. for 3 minutes in an oven and aged at 23° C. and 50% RH for 7 days to form a 25 μm thick adhesive layer on the release sheet.

[0148] Here, the weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

[0149] <Measurement conditions>

[0150] ·GPC measuring apparatus: manufactured by TOSOH CORPORATION, HLC-8320

[0151] ·GPC columns (passed in the following order): manufactured by TOSOH CORPORATION

[0152] TSK gel superH-H

[0153] TSK gel superHM-H

[0154] TSK gel superH2000

[0155] ·Test solvent: tetrahydrofuran

[0156] ·Measurement temperature: 40℃

[0157] (3) Formation of a writing feel improving sheet

[0158] The surface on the substrate side of the laminate of the substrate and the writing feel improving layer obtained in the above step (1) is bonded to the surface on the adhesive layer side of the laminate of the release sheet and the adhesive layer obtained in the above step (2), thereby obtaining a writing feel improving sheet in which the writing feel improving layer, the substrate, the adhesive layer and the release sheet are laminated in this order.

[0159] [Examples 2 to 5, Comparative Examples 1 to 2]

[0160] A writing feel-improving sheet was prepared in the same manner as in Example 1 except that the type of coating composition used and the thickness of the writing feel-improving layer were changed as shown in Table 3.

[0161] [Test Example 1] (Measurement of optical properties)

[0162] The release sheet was peeled off from the writing feel improving sheet produced in Examples and Comparative Examples, and the exposed surface (adhesive surface) of the exposed adhesive layer was bonded to a glass plate (thickness: 1.2 mm) to prepare a measurement sample.

[0163] Then, after background measurement was performed on the glass plate alone, the haze value (%) of the writing feel improving sheet was measured for the measurement sample using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with JIS K7136:2000, and the total light transmittance (%) of the writing feel improving sheet was measured in accordance with JIS Z 8741:1997. These results are shown in Table 3.

[0164] [Test Example 2] (Measurement of pencil hardness)

[0165] The release sheet was peeled off from the writing feel improving sheet produced in Examples and Comparative Examples, and the exposed surface (adhesive surface) of the exposed adhesive layer was bonded to a glass plate (thickness: 1.2 mm) to prepare a measurement sample.

[0166] The writing feel improving layer side surface (stylus pen contact surface) of the above-mentioned sample for measurement was measured for scratch hardness by a pencil scratch coating hardness tester (manufactured by Toyo Seiki Seisaku-sho, Ltd., product name "NP") under the conditions of a load of 750 g and a speed of 1.0 mm / s according to JIS K5600-5-4:1999. The results are shown in Table 3.

[0167] [Test Example 3] (Evaluation of scratch resistance)

[0168] The release sheet was peeled off from the writing feel improving sheet produced in Examples and Comparative Examples, and the exposed surface (adhesive surface) of the exposed adhesive layer was bonded to a glass plate (thickness: 1.2 mm) to prepare a measurement sample.

[0169] Use #0000 steel wool at 125g / cm 2 The writing feel improving layer side of the measurement sample (stylus pen contact surface) was rubbed back and forth 10 times at a speed of 10 cm with a load of . The surface of the writing feel improving layer was visually confirmed under a three-wavelength fluorescent lamp, and the scratch resistance was evaluated using the following criteria. The results are shown in Table 3.

[0170] A: No injuries were found.

[0171] B: Less than 10 scars were confirmed.

[0172] C: 11 or more scars were confirmed.

[0173] [Test Example 3] (Friction Measurement)

[0174] Peel off the release sheet from the writing feeling improvement sheets produced in the examples and comparative examples, and bond the exposed surface (adhesive surface) of the exposed adhesive layer to a glass plate (thickness: 1.2 mm), and use this as a measurement sample.

[0175] Place the above measurement sample on the dedicated measurement bogie of a static and kinetic friction measuring instrument (manufactured by Trinity-Lab inc., product name "Tribomaster TL201Ts") with the surface on the side of the writing feeling improvement layer (the contact surface of the stylus) facing upward. In addition, as the static and kinetic friction measuring instrument is used, the dedicated measurement bogie reciprocates in a specified direction while keeping the setting surface of the measurement sample horizontal.

[0176] Next, fix a stylus (test stylus) to the above static and kinetic friction measuring instrument in such a way that the tip of the stylus contacts the contact surface of the stylus. At this time, tilt the stylus at an angle of 45° with respect to the contact surface of the stylus and fix it. In addition, set the tilt direction at this time to tilt toward the traveling direction side of the dedicated measurement bogie and parallel to the traveling direction. As the above stylus, use a stylus (manufactured by WACOM Co., product name "ACK-20004", diameter of the tip: 0.5 mm) having a tip made of an elastic body.

[0177] Next, apply a load of 200 g to the stylus under a pressing condition, and in this state, move the dedicated measurement bogie at four speeds (sliding speeds) of 1.5 mm / s, 20 mm / s, 50 mm / s, and 80 mm / s, thereby causing the stylus to slide on the contact surface of the stylus (sliding distance: 100 mm), and calculate the coefficient of kinetic friction at each sliding speed based on the friction force measured at this time.

[0178] Show these results in Table 3.

[0179] In addition, for reference, in the same manner as above, measure the coefficient of kinetic friction when writing on paper with a writing tool. Specifically, commercially available paper (manufactured by KOKUYO Co., Ltd., product name "Campus loose-leaf しっかり書ける", product model

[0180] After 20 sheets of paper (No. S836BT, size: B5, line spacing: B type) were stacked and placed on the measurement-dedicated truck of the static and dynamic friction measuring instrument, the writing tool was fixed to the static and dynamic friction measuring instrument in such a way that the pen tip was in contact with the outermost surface of the stacked paper. Here, as writing tools, ballpoint pen A (Bic Japan. manufactured, product name "Orange EG 0.7", oil-based ballpoint pen, pen tip diameter: 0.7 mm) and ballpoint pen B (Bic Japan. manufactured, product name

[0181] "Orange EG 1.0", oil-based ballpoint pen, pen tip diameter: 1.0 mm) and pencil (manufactured by MITSUBISHI PENCIL CO., LTD., product name "Mitsubishi Pencil Uni B", core hardness: B). Then, the writing tool was slid on the surface of the paper at the four sliding speeds as described above, and the dynamic friction coefficient was calculated based on the friction force measured at this time. These results are also shown in Table 3.

[0182] Then, the kinetic friction coefficients at four sliding speeds of the examples, comparative examples and reference examples obtained as described above are plotted on a coordinate plane with the sliding speed as the horizontal axis (X axis) (unit: mm / sec) and the kinetic friction coefficient as the vertical axis (Y axis).

[0183] Then, in the above-mentioned coordinate plane, the slope of the line segment connecting the coordinate at a sliding speed of 1.5 mm / second and the coordinate at a sliding speed of 20 mm / second (the slope marked as "for 20 mm / second" in Table 3), the slope of the line segment connecting the coordinate at a sliding speed of 1.5 mm / second and the coordinate at a sliding speed of 50 mm / second (the slope marked as "for 50 mm / second" in Table 3) and the intercept (the intercept marked as "for 50 mm / second" in Table 3), and the slope of the line segment connecting the coordinate at a sliding speed of 1.5 mm / second and the coordinate at a sliding speed of 80 mm / second (the slope marked as "for 80 mm / second" in Table 3) were calculated. These results are also shown in Table 3.

[0184] In addition, in the above coordinate plane, the coordinates of the four points with sliding speeds of 1.5 mm / s, 20 mm / s, 50 mm / s and 80 mm / s are approximated by polynomials to obtain an expression of an approximate curve. Then, the values ​​of coefficients a, b and c when this expression is recorded as the following formula (1) are shown in Table 3.

[0185] Y=aX 2 +bX+c···(1)

[0186] [Test Example 4] (Evaluation of writing feeling)

[0187] The release sheet was peeled off from the writing feel improving sheet produced in Examples and Comparative Examples, and the exposed surface (adhesive surface) of the exposed adhesive layer was bonded to a glass plate (thickness: 1.2 mm) to prepare a measurement sample.

[0188] The evaluator used the same stylus pen as used in the friction measurement of Test Example 3 to simulate a predetermined writing operation on the writing feel improving layer side surface (stylus pen contact surface) of the measurement sample and evaluated the writing feel based on the following criteria. The results are shown in Table 3.

[0189] ◎: Excellent writing feel was obtained.

[0190] ○: Although not good enough to be called "excellent writing feel", a good writing feel within the allowable range was obtained.

[0191] ×: The writing feeling is poor.

[0192] [Table 1]

[0193]

[0194] [Table 2]

[0195]

[0196]

[0197] As shown in Table 3, the writing feel improving sheet produced in the examples can well reproduce the writing feel when writing on paper with a writing instrument, and can achieve excellent writing feel. In addition, the writing feel improving sheet produced in the examples also obtained good results in the evaluation of various optical properties.

[0198] Industrial Applicability

[0199] The writing feel improving sheet of the present invention can be suitably used as the outermost layer of a touch panel using a stylus pen.

Claims

1. A writing feel improving sheet, which is a writing feel improving sheet having a stylus pen contact surface to be contacted by a stylus pen, characterized in that: The writing feel improving sheet comprises a writing feel improving layer and a substrate provided on one side of the writing feel improving layer. The surface of the writing feel improving layer opposite to the substrate is the stylus pen contact surface. The writing feel improving layer is formed by curing a coating composition containing a curable component and fine particles. The average particle size of the microparticles is 1 μm or more and 8 μm or less. The content of the fine particles is 0.01 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the curable component. After the tip of a stylus having a tip of 0.5 mm in diameter is brought into contact with the stylus contact surface, a load of 200 g is applied to the stylus, and the stylus is linearly slid at a predetermined sliding speed while maintaining the angle between the stylus and the stylus contact surface at 45°. The dynamic friction coefficient measured at this time is: The dynamic friction coefficient when the sliding speed is 1.5 mm / s is 0.13 or more and 0.35 or less, The dynamic friction coefficient when the sliding speed is 20 mm / s is 0.15 or more and 0.40 or less, The dynamic friction coefficient when the sliding speed is 50 mm / s is 0.18 or more and 0.45 or less, and The dynamic friction coefficient when the sliding speed is 80 mm / s is 0.18 or more and 0.47 or less.

2. A writing feel improving sheet having a stylus contact surface to be contacted by a stylus, characterized in that: The writing feel improving sheet comprises a writing feel improving layer and a substrate provided on one side of the writing feel improving layer. The surface of the writing feel improving layer opposite to the substrate is the stylus pen contact surface. The writing feel improving layer is formed by curing a coating composition containing a curable component and fine particles. The average particle size of the microparticles is 1 μm or more and 8 μm or less. The content of the fine particles is 0.01 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the curable component. After the tip of a stylus having a tip of 0.5 mm in diameter is brought into contact with the stylus contact surface, a load of 200 g is applied to the stylus, and the stylus is linearly slid at a predetermined sliding speed while maintaining the angle between the stylus and the stylus contact surface at 45°. The dynamic friction coefficient measured at this time is: When the measurement results are plotted on a coordinate plane with the sliding speed as the horizontal axis (unit: mm / second) and the dynamic friction coefficient as the vertical axis, The slope of a line segment connecting the coordinate at the sliding speed of 1.5 mm / sec and the coordinate at the sliding speed of 50 mm / sec is greater than 0.0006 and less than 0.0072.

3. A writing feel improving sheet, which is a writing feel improving sheet having a stylus pen contact surface to be contacted by a stylus pen, characterized in that: The writing feel improving sheet comprises a writing feel improving layer and a substrate provided on one side of the writing feel improving layer. The surface of the writing feel improving layer opposite to the substrate is the stylus pen contact surface. The writing feel improving layer is formed by curing a coating composition containing a curable component and fine particles. The average particle size of the microparticles is 1 μm or more and 8 μm or less. The content of the fine particles is 0.01 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the curable component. After the tip of a stylus having a tip of 0.5 mm in diameter is brought into contact with the stylus contact surface, a load of 200 g is applied to the stylus, and the stylus is linearly slid at a predetermined sliding speed while maintaining the angle between the stylus and the stylus contact surface at 45°. The dynamic friction coefficient measured at this time is: When the measurement results are plotted on a coordinate plane with the sliding speed as the horizontal axis (X axis) (unit: mm / sec) and the dynamic friction coefficient as the vertical axis (Y axis), The approximate curve obtained by performing polynomial approximation on the coordinates of the four points of the sliding speed of 1.5 mm / s, the sliding speed of 20 mm / s, the sliding speed of 50 mm / s, and the sliding speed of 80 mm / s satisfies the following equations (1) to (4): Y=aX 2 +bX+c···(1); -5×10 -5 ≤a≤-5×10 -6 ···(2)； 0.0001≤b≤0.008···(3)； 0.11≤c≤0.31···(4)。 4. The writing feeling improving sheet according to any one of claims 1 to 3, characterized in that The coating composition contains a reactive fluorine-based oligomer.

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