JP2012168729A - Pen tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pen tip having electric conductivity used for an electronic pen, which hardly causes a stain due to friction.SOLUTION: A pen tip for electronic pen used for input to a touch panel, comprises an electric conductive elastomer containing elastomer resin and nanocarbon dispersed in the elastomer resin, in which volume resistivity of the electric conductive elastomer is 10to 10Ω cm.

Description

  The present invention relates to an electronic pen used in a device that is operated by touching a screen such as a touch panel, and particularly relates to a pen tip of the electronic pen that requires electrical conductivity.

  2. Description of the Related Art In recent years, touch panels that can be operated by touching a screen or the like have been adopted as operation means in the fields of personal computers and portable music playback devices. The touch panel functions as an operation means by detecting a touched position such as a monitor display screen or a screen projected by a projector.

  Generally, a finger and an electronic pen are used for input of these touch panels (Patent Document 1). The pen tip of an electronic pen used in some methods such as an electromagnetic induction method and a capacitance method is required to have conductivity. For the nib having conductivity, a conductive rubber, a conductive resin, a conductive sponge, or the like that is generally mixed with a conductive material such as carbon black having conductivity is used. Furthermore, indium vapor deposition can be performed on the nib to impart conductivity and slipperiness.

JP 2008-204375 A

  When carbon black is used to impart conductivity to the pen tip, there is a problem that the monitor and the screen are easily soiled by touching the screen during operation with the electronic pen. Therefore, an object of the present invention is to provide a nib having conductivity that is used for an electronic pen, and is difficult to be stained by rubbing.

The present invention (1) comprises a conductive elastomer containing an elastomer resin and nanocarbon dispersed in the elastomer resin,
An electronic pen nib used for touch panel input, wherein the conductive elastomer has a volume resistance of 10 ⁰ to 10 ² Ω · cm.

  The present invention (2) is the nib of the invention (1), wherein the nanocarbon is a carbon nanotube.

  The present invention (3) is the nib of the invention (1) or (2), wherein the conductive elastomer further contains a white pigment.

The present invention (4) includes a nib body,
A connection fixing part with an external electronic pen body provided in a part of the body;
A pen tip having a round shape provided at one end of the main body, and the pen tip according to any one of the inventions (1) to (3).

  In the present invention, by selecting nanocarbon (particularly, carbon nanotube) as a component for imparting conductivity of a conductive elastomer used for a nib, the nib is rubbed even if it has sufficient conductivity. There is an effect that the black shift due to can be remarkably reduced.

FIG. 1 is a schematic configuration diagram of a nib 1 according to the present invention. FIG. 2 is a diagram showing a schematic structure of the electronic pen 2 to which the pen tip 1 according to the present invention is attached.

The nib according to the present invention is made of a conductive elastomer containing an elastomer resin and nanocarbon dispersed in the elastomer resin. The volume resistance of the conductive elastomer according to the present invention is 10 ⁰ to 10 ² Ω · cm. By having the conductivity, it can be used as a pen tip of an electronic pen used for input of a touch panel. The “pen tip” in the present invention means a member constituting a tip portion that comes into contact with a touch panel of a touch panel input tool such as an electronic pen.

  According to the present invention, by selecting nanocarbon (particularly, carbon nanotube) as the conductive filler, it is possible to reduce black migration due to rubbing of the pen tip. Further, by selecting nanocarbon, sufficient conductivity can be imparted even with a small amount of addition. By adding the small amount, (1) the effect of reducing the above-described black shift becomes remarkable, and (2) the effect of producing a gray color can be obtained. Regarding (1), the fact that the addition amount of the conductive filler is small means that the addition amount of the black component (carbons) that causes the color migration is also reduced, so that the color migration is particularly remarkable. Preventive effect is obtained. About (2), since the addition amount of carbons which are also black components can be reduced as described above, a gray color can be obtained by adding a white pigment. Therefore, since the conductive elastomer itself is no longer black, the rubbed counterpart is less likely to be black.

  The conductive elastomer of the nib according to the present invention contains nanocarbon as a conductive filler. “Nanocarbon” means carbon having a size of at least one side of 1000 nm or less (preferably 500 nm or less) in the shape of the material. For example, carbon nanotube (single-walled / double-walled / multi-layered type, cup Stack type), carbon nanofiber, carbon nanohorn or fullerene. Among these nanocarbons, carbon nanotubes are preferable. By selecting the carbon nanotube, it is particularly difficult to get dirt, and in addition, since a pen tip with a small amount of the component added is obtained, it is particularly difficult to get dirt. The carbon nanotube may be a single wall carbon nanotube (SWCNT) or a multi-wall carbon nanotube (MWCNT). The length of the carbon nanotube is preferably from 0.1 to 100 μm, more preferably from 0.1 to 50 μm, and further preferably from 0.1 to 20 μm. The diameter of the carbon nanotube is preferably 5 to 200 nm, more preferably 8 to 160 nm, and still more preferably 9 to 120 nm. The aspect ratio ([length] / [diameter]) of the carbon nanotube is preferably 20 to 3000, more preferably 40 to 2000, and still more preferably 100 to 1200. By selecting carbon nanotubes having an aspect ratio within the above range, the carbon nanotubes can be easily entangled with each other, and high conductivity can be obtained. In addition, the length and diameter of the tube are measured with respect to 100 or more structures existing within a predetermined range using an AFM (atomic force microscope), and set to a range in which 90% or more are included. In addition, the content of nanocarbon in the conductive elastomer is preferably 1 to 10% by mass, more preferably 2 to 8% by mass, and further 3 to 5% by mass with respect to the entire conductive elastomer. Is preferred. By setting the addition amount within the range, a nib having a gray color can be obtained.

  As the conductive filler, the above-mentioned nanocarbon may be used alone, or two or more kinds may be used in combination. Furthermore, in combination with nanocarbon, one or more other conductive fillers such as carbon black, metal filler, and metal oxide filler can be used in combination.

  In the conductive elastomer of the nib according to the present invention, an elastomer resin is used. By selecting an elastomer resin as the nib material, the touch panel is hardly damaged. In relation to the selection of the nanocarbon, the invention can obtain the required conductivity by adding a small amount of a conductive filler, so that the physical properties of the base material hardly change due to the conductive filler. In other words, the characteristics of the resin serving as the base material can be maintained by the selection. In connection with the property, by using an elastomer (elastic body) as a nib material, it becomes difficult to damage the surface of the touch panel when the input pen is used.

  As the elastomer resin, various elastomer resins can be used. For example, an elastomer resin such as a rubber elastomer resin, a polyurethane elastomer, a polyolefin elastomer, or the like can be used. A rubber-based elastomer resin is preferred.

  The rubber-based elastomer resin includes natural rubber, ethylene / propylene rubber (EPR), ethylene / propylene / diene monomer rubber (EPDM), styrene block copolymer rubber (SEBS, SI, SIS, SB, SBS, SIBS, etc.) S is styrene, EB is random ethylene + butene, I is isobutylene, and B is butadiene), butyl rubber, halobutyl rubber, isobutylene / para-alkylstyrene copolymer, isobutylene / para-alkylstyrene copolymer, isobutylene / para -Alkylstyrene halogenated copolymer, polyisobutylene, acrylonitrile / butadiene copolymer, polychloroprene, alkyl acrylate rubber, chlorinated isobutylene rubber, acrylonitrile isobutylene chloride Beam, and a polybutadiene rubber. Among these elastomers, ethylene / α-olefin / diene terpolymers such as ethylene / propylene / diene monomer rubber (EPDM) are preferred.

  Examples of the thermoplastic elastomer resin include styrene elastomers, olefin elastomers, vinyl chloride elastomers, urethane elastomers, ester elastomers, and amide elastomers. Of these thermoplastic elastomers, styrene elastomers and olefin elastomers are suitable. Examples of the styrene elastomer include a polystyrene-polyolefin block copolymer. More specifically, polystyrene-poly (ethylene / propylene) block (SEP), polystyrene-poly (ethylene / propylene) block-polystyrene (SEPS), polystyrene-poly (ethylene / butylene) block-polystyrene (SEBS), polystyrene -Poly (ethylene-ethylene / propylene) block-polystyrene (SEEPS). Examples of the olefin-based elastomer include olefin-based thermoplastic elastomer (TPO) and dynamically cross-linked olefin-based thermoplastic elastomer (TPV).

  Examples of polyurethane-based elastomer resins include polyaddition of adipate-type polyester polyols having hydroxyl groups at both ends by condensation of 1,4-butanediol and adipic acid and hexamethylene diisocyanate (HDI), which is a short-chain diisocyanate. The thermoplastic polyurethane etc. which are produced | generated by reaction (urethanization reaction) etc. are mentioned.

  As the polyolefin-based thermoplastic elastomer resin, an elastomer resin having a sea-island structure typified by Santoprene can be used as a commercially available product.

  In addition, as for content of the elastomer resin in a conductive elastomer, 20-80 mass% is suitable with respect to the whole conductive elastomer, 30-70 mass% is more suitable, and 40-65 mass% is further. Is preferred.

  The conductive elastomer according to the present invention preferably contains a white pigment. By containing a white pigment, the color of the nib can be made gray, so that color transfer is difficult. Although it does not specifically limit as a white pigment, For example, inorganic white pigments, such as a titanium oxide, are suitable, and since it has little influence on the mechanical physical property of an electroconductive elastomer, a titanium oxide is especially suitable. As for content of a white pigment, 1-40 are suitable for mass ratio (white pigment / nanocarbon) with respect to nanocarbon, and 3-20 are more suitable.

  It is particularly preferable to add a softening agent to the conductive elastomer used in the present invention. By adding a softening agent, the surface of a display or the like is hardly damaged by making the pen tip moderately hard. Examples of the softening agent include oil. The oil of the softening agent is not particularly limited, and various oils such as mineral oil, vegetable oil, and synthetic oil can be used. Examples of the mineral oil-based oil include naphthenic and paraffinic process oils. Examples of vegetable oils include castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, and the like. The content of these softeners is preferably 1 to 150 parts by weight with respect to 100 parts by weight of the elastomer resin.

  The conductive elastomer according to the present invention can contain, as an optional component, fillers other than the conductive filler, such as glass fibers, and other inorganic and organic fillers. Various additives generally used in the resin / rubber industry can be used. For example, a vulcanizing agent, a reinforcing agent, an antioxidant / anti-aging agent, a colorant and the like can be mentioned. 1-30 mass% is suitable for these arbitrary components with respect to the whole conductive elastomer, 3-20 mass% is suitable, and 4-15 mass% is still more suitable.

The volume resistance of the conductive elastomer according to the present invention is 10 ⁰ to 10 ² Ω · cm. Further, the surface resistance of the nib according to the present invention is not particularly limited, but is preferably 10 ⁰ to 10 ³ Ω / □, and more preferably 10 ¹ to 10 ³ Ω / □. The hardness of the conductive elastomer is preferably 40 to 80, more preferably 45 to 70, and still more preferably 45 to 65. Here, the hardness is a value obtained by measurement of a durometer hardness test (type A) based on JISK 6253.

  The conductive elastomer according to the present invention can be produced by a known method. For example, the elastomer and nanocarbon can be kneaded by kneading. Here, the kneading can be performed using a known kneading apparatus such as a kneader, a lab plast mill, or a roll. Although the nib which concerns on this invention can be manufactured by a well-known method, it can be manufactured by compression molding or injection molding, for example.

  Next, the structure of the pen tip according to the present invention will be described. FIG. 1 is a schematic configuration diagram of a nib 1 according to the present invention. 1A is a bottom view of the nib according to the present invention, FIG. 1B is a side view of the nib according to the present invention, and FIG. 1C is an AA cross-sectional view of the nib. .

  The nib 1 includes a nib body 10 having a cylindrical shape, a tip part 11 having a round shape formed at one end of the nib body, and a connection fixing part 13 for connecting an electronic pen body formed in the nib body. Have The connection fixing portion 13 is not particularly limited as long as it can be connected to an external electronic pen main body, and may have a body portion that is long enough to hold the electronic pen main body. In addition, the fitting hole 15 may be provided in the edge part opposite to the front-end | tip part of a nib main body as a part of connection fixed part. In addition to the fitting hole 15, a fixing groove or a fixing protrusion may be formed on the side surface of the nib body as a part of the connection fixing portion. Here, the nib according to the present invention is the conductive elastomer according to the present invention.

  FIG. 2 is a diagram showing a schematic structure of an electronic pen on which a pen tip according to the present invention is mounted. 2A is a side view of the electronic pen, FIG. 2B is a cross-sectional view of the electronic pen, and FIG. 2C shows an attaching / detaching mechanism of the electronic pen body and the pen tip constituting the electronic pen. FIG. Here, an example of an electronic pen used in an electrostatic touch panel is shown.

  The electronic pen 2 includes an electronic pen main body 3 that imitates the shape of a writing instrument, and a pen tip 1 that is attached to the tip of the main body. The electronic pen body 3 includes a case 31 having a hollow cylindrical shape and a tip portion 34 to which a pen tip is attached. The electronic pen body is formed of a conductive material such as a conductive resin or metal. The distal end portion 34 is electrically connected to the case 31 and is formed in contact with the case 31 or formed integrally therewith. Moreover, the front-end | tip part 34 has a taper shape, and the pen tip mounting hole 35 is formed in the said taper-shaped edge part. Further, the pen tip mounting hole 35 is provided with a fitting protrusion 37 to be inserted into the fitting hole 15 of the pen tip.

  As described above, the electronic pen body 3 and the pen tip 1 are configured to be detachable, and it is preferable that the electronic pen body 3 and the pen tip 1 be exchangeable when the pen tip 1 deteriorates due to use. Specifically, the pen nib 1 is inserted into the pen nib mounting hole 35 of the electronic pen body 3, and the connection fixing part 13 is gripped by the inner wall surface of the pen nib mounting hole 35. Further, since the fitting projection 37 of the electronic pen body is inserted into the fitting hole 15 of the pen tip 1, the connection between the electronic pen body and the pen tip becomes more stable. In addition, since the nib 1 and the electronic pen main body 3 have conductivity, they are electrically connected.

  When the user holds the electronic pen 2 in his hand and touches the touch panel with the pen tip 1, the capacitance of the detection electrode corresponding to that portion changes, so that the touched position can be detected. In addition, although the example of the electronic pen used with an electrostatic touch panel is shown here, the said electronic pen may be provided with the coil inside as an electronic pen for electromagnetic induction systems.

  Note that a metal layer may be deposited on the surface of the nib according to the present invention. As a metal layer, an indium vapor deposition layer, a tin vapor deposition layer, chromium vapor deposition, and aluminum vapor deposition are mentioned.

Examples 1-6
Each material was mix | blended with the following composition ratio of Table 1, and the conductive elastomer was adjusted. The composition of the CNT master batch used for the conductive elastomer is shown in Table 2. “FloTube 9000” had a diameter of 11 nm, a length of 11 μm, and an aspect ratio of 1000.

  In Examples 1 to 6, EPT-3045 and CNT master batch were kneaded at 120 ° C. for 3 minutes with a kneader, and then Tronox R-FD-1, two types of zinc oxide and stearic acid were added and kneaded for 5 minutes. The kneaded product was discharged. Renogran ZDBC-80, Renogran CBS-80, Sunmix TT-75E, Sunmix TRA-70E and Renogran S-80 were added to the kneaded product by a roll and kneaded to obtain a kneaded product. The kneaded product was vulcanized at 170 ° C. for 10 minutes by a hot press using a 2 mm spacer to obtain a conductive elastomer for measuring physical properties. The conductive elastomer was gray. In addition, when the test body was rubbed with the said conductive elastomer and the test of a color transfer damage | wound was done, the color transfer and damage to a test body did not generate | occur | produce.

  The following physical property test was done about the conductive elastomer which concerns on Examples 1-6. The values obtained from the tests are shown in Table 1.

Hardness (A type): Measured with a durometer (type A) in accordance with JIS K6253.
Volume resistance and surface resistance: Resistance measuring device (Mitsubishi Chemical, Loresta GP
MCP-T610) was measured by a four-probe method.

(Example 7)
Instead of “NC7000” (manufactured by Nanosil Co., Ltd., multiwall carbon nanotube (tube diameter: 8 to 10 nm, length: about 1.5 μm, aspect ratio: 188 to 150)), Created. A kneaded product was obtained in the same formulation as in Example 3. The volume resistivity (Ω · cm) was 3.98E + 00, and the surface resistivity (Ω / □) was 2.15E + 01, which was almost equivalent to that of Example 3.

DESCRIPTION OF SYMBOLS 1 Pen tip 10 Pen tip main body 11 Tip part 13 Connection fixing part 2 Electronic pen 3 Electronic pen main body

Claims (4)

It consists of a conductive elastomer containing an elastomer resin and nanocarbon dispersed in the elastomer resin,
An electronic pen nib used for touch panel input, wherein the conductive elastomer has a volume resistance of 10 ⁰ to 10 ² Ω · cm.   The nib according to claim 1, wherein the nanocarbon is a carbon nanotube.   The nib according to claim 1, wherein the conductive elastomer further contains a white pigment. The nib body,
A connection fixing part with an external electronic pen body provided in a part of the body;
The pen tip according to any one of claims 1 to 3, comprising a pen tip portion having a round shape provided at one end of the main body.

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