JP5852821B2 - Antistatic shoes - Google Patents

Description

  The present invention relates to an antistatic shoe for discharging static electricity accumulated in the body of an operator or the like to a floor in a factory or the like.

  For example, a clean room used in the manufacturing process of electronic components such as semiconductor elements, etc., or an environment that requires a high level of dustproof performance, or because of handling organic solvents and gases, it is required to highly prevent the occurrence of electrostatic sparks. In the environment, etc., conductivity was given to discharge static electricity accumulated in the body by the worker's work by discharging it to the floor through the outer bottom surface of the shoe sole in contact with the floor surface. An antistatic floor is used in combination with an antistatic shoe with conductivity imparted to the shoe sole.

As the antistatic shoe, the temperature between the middle bottom surface of the shoe sole (the surface where the sole contacts) and the outer bottom surface as defined in Japanese Industrial Standard JIS T8103 _{: 2010} “Static Antistatic Shoes” is 23 ±. Examples thereof include an electrostatic shoe ED having a total resistance value at 2 ° C. of 10 ⁵ Ω or more and 10 ⁸ Ω or less, or an electrostatic shoe EDX having a total resistance value of 10 ⁵ Ω or more and 10 ⁷ Ω or less. The reason why the total resistance value is 10 ⁵ Ω or more is to prevent electric shock due to electric leakage. The reason why the total resistance value is 10 ⁸ Ω or less is to discharge the static electricity accumulated in the worker's body to the floor surface through the shoe sole.

However, in recent years, the antistatic floor and the antistatic shoes are also provided with an antistatic floor and an antistatic shoe in order to prevent the electronic parts from being destroyed by static electricity generated when the worker walks or works on the floor. Therefore, it has been required to have a performance capable of suppressing the static electricity accumulated in the semiconductor to be lower than before.
For example, in a factory that handles electronic components that are destroyed by static electricity of 100 V or less, in the future, the potential of static electricity accumulated in the worker's body due to charging when walking or working on the floor, the so-called human body charging potential is set. It is expected to have a performance that can be suppressed to several tens of volts or less.

However, it is particularly difficult to combine thick anti-static floor-type antistatic floors, which are often used on the floors of factories that use automated carts and carts loaded with heavy objects, with conventional antistatic shoes. The demand cannot be fully met.
When combined with the thick-coated sink floor type antistatic floor, etc., the antistatic shoe suppresses the generated static electricity through the shoe sole as quickly as possible in order to keep the charged potential of the human body below the tens of volts. It is necessary to have the ability to discharge to the floor.

However, the resistance value of the shoe sole of the antistatic shoe is specified to be 10 ⁵ Ω or more in order to prevent an electric shock due to leakage as described above, and while maintaining the specified value in consideration of safety, the discharge performance is also maintained. It is not easy to improve.
For example, Patent Document 1 includes a shoe sole composed of three layers of an insole (insole), a midsole, and an outsole (outer sole),
The resistance value between the outer bottom surface of the outsole and the interface with the midsole (upper surface) is set to 10 ⁵ Ω to 10 ⁷ Ω, and a conductive portion is provided on the front portion of the upper surface (toe side of the arch),
The midsole is provided with a slit that penetrates the midsole in the thickness direction, and a conductive tape is inserted to form an annular conductor, and the front of the insole (toe side from the arch) touches the sole The upper surface to be formed, that is, so as to have conductivity from the inner bottom surface of the shoe sole to the interface (lower surface) with the midsole,
An antistatic shoe is described in which the conductive portion, the conductor, and the front portion of the insole are electrically connected.

Patent Document 2 discloses that
The midsole is integrally formed with foamed resin in a shape having a communicating portion that penetrates in the thickness direction at a position corresponding to the arch,
The outsole and the insole are each integrally formed into a shape having convex portions that are inserted into the communication portion and connected to each other by rubber mixed with a conductive substance, respectively.
An antistatic shoe is described in which an outsole and an insole are electrically connected by connecting the convex portions.

However, any of the above antistatic shoes is insufficient in the effect of quickly discharging the static electricity accumulated in the worker's body to the floor.
For example, in the antistatic shoe disclosed in Patent Document 1, static electricity accumulated in the operator's body leaks to the outsole using the electrically conductive portion, the conductor, and the front portion of the insole as described above as a leakage path. Is done. Further, in the antistatic shoe of Patent Document 2, static electricity is leaked to the outsole using a portion where the outsole and the insole are connected as a leakage path.

However, the resistance value of the shoe sole is specified to be 10 ⁵ Ω or more in order to prevent electric shock due to electric leakage as described above, and the resistance value in the surface direction of the outer bottom surface of the shoe sole is about the same.
Therefore, any antistatic shoe selectively leaked to the outsole through the leakage path when a limited area corresponding to the leakage path (electrostatic outlet) in the outer bottom surface was in contact with the floor surface. Although static electricity can be quickly discharged to the floor, the static electricity cannot be discharged to the floor even if other areas are in contact with the floor surface.

On the other hand, in particular, there is uneven surface conductivity in the sink type antistatic floor, and the floor has a mixture of high and low conductivity areas. Only the high area functions as an entrance for static electricity to accept static electricity from antistatic shoes.
Therefore, except when the static electricity outlet of the antistatic shoe is in contact with the static electricity inlet of the floor surface, even if the antistatic shoe is in contact with the floor surface, the static electricity is promptly transferred from the antistatic shoe to the floor. It cannot be discharged. In other words, static electricity can be quickly discharged to the floor only when the static electricity exit of the antistatic shoe and the static electricity entrance of the floor come into contact with each other.

  For this reason, the antistatic shoes having any of the above structures are not effective enough to quickly discharge the static electricity accumulated in the worker's body to the floor. It cannot be kept below 10V.

JP 2008-228850 A JP 2011-83481 A

The object of the present invention is to maintain the resistance value of the shoe sole at a prescribed value of 10 ⁵ Ω or more to reliably prevent electric shock due to electric leakage, and to quickly collect static electricity accumulated in the operator's body. It is another object of the present invention to provide an antistatic shoe that can discharge to the floor and suppress the human body charging potential to several tens of volts or less.

In order to solve the above-mentioned problem, the inventor reexamined the mechanism of electrostatic discharge between the shoe sole and the floor.
As a result, the resistance value in the surface direction of the shoe sole in the vicinity of the outer bottom surface in contact with the floor surface is greatly related to the discharge of static electricity to the floor. While maintaining the total resistance value up to the bottom surface at a prescribed value of 10 ⁵ Ω or more, by selectively reducing only the resistance value in the surface direction in the vicinity of the outer bottom surface, static electricity is reduced in the surface direction. I found out that it should be easy to leak.

The inventor has further studied the specific structure of the sole for realizing the above-described configuration and the range of the resistance value in the surface direction, and as a result, the present invention has been completed.
That is, the present invention is an antistatic shoe having a bottom surface layer constituting the outer bottom surface of the shoe bottom and continuing substantially over the entire outer bottom surface, and the bottom layer itself has a temperature of 23 ± 2 ° C., Japanese Industrial Standard JIS C61340-4-1: 2008 (IEC 61340-4-1: 2003) "Static Static-Part 4-1: Standard Test Methods for Specific Applications in an Environment of Relative Humidity 50 ± 5% -The resistance value measured in accordance with the measurement method specified in "The electrical resistance of floor finish and construction floor" is 0Ω or more and 5 × 10 ³ Ω or less, and the bottom layer is formed from the middle bottom surface of the shoe sole. The total resistance value up to the outer bottom surface is 10 ⁵ Ω or more and 10 ⁸ Ω or less.

According to the present invention, the static electricity accumulated in the worker's body is quickly leaked in the surface direction through the bottom layer having a resistance value of 0Ω or more and 5 × 10 ³ Ω or less as described above, and It can be discharged from any position to the floor. That is, according to the antistatic shoe of the present invention, substantially the entire outer bottom surface can function as an outlet for static electricity.
Therefore, even if it is a non-static floor-type antistatic floor with uneven conductivity, and static electricity inlets scattered on the floor surface, the static electricity inlet and the static electricity outlet of the antistatic shoe, That is, the chance of contact with the substantially entire surface of the outer bottom surface can be greatly increased, and the static electricity can be quickly discharged from the antistatic shoe to the floor.

Therefore, according to the present invention, the total resistance value between the outer bottom surface and the middle bottom surface is set to 10 ⁵ Ω or more to prevent electric shock due to electric leakage, and the total resistance value is set to 10 ⁸ Ω or less, Combined with the ability to smoothly leak the static electricity accumulated in the bottom of the shoe in the thickness direction of the shoe sole, it is possible to prevent the electric shock due to the above-mentioned electric leakage, while still ensuring that the static electricity accumulated in the operator's body is faster than before. It is possible to suppress the charging potential of the human body to several tens of volts or less by discharging to the floor.

Further, according to the present invention, the resistance value is 0Ω or more, 5 × 10 ³ Ω on the bottom layer of the conventional shoe sole in which the total resistance value in the thickness direction is in the range of 10 ⁵ Ω or more and 10 ⁸ Ω or less. The antistatic shoe of the present invention can be easily produced with high productivity without adopting a complicated structure such as the antistatic shoe described in Patent Documents 1 and 2 by simply forming the bottom layer as described below. There is also an advantage of being able to do it.
That is, a bottom layer having a resistance value of 0Ω or more and 5 × 10 ³ Ω or less is formed on the bottom layer of the shoe sole in which the total resistance value in the thickness direction is in the range of 10 ⁵ Ω or more and 10 ⁸ Ω or less. However, the total resistance value is hardly affected.

For example, when the total resistance value in the thickness direction of the shoe sole before forming the bottom layer is 1 × 10 ⁶ Ω and the resistance value of the bottom layer is 5 × 10 ³ Ω , for example, the bottom layer The total resistance value of the shoe sole after forming
1 × 10 ⁶ Ω + 5 × 10 ³ Ω≈1 × 10 ⁶ Ω
It becomes. Similarly, considering the case where the resistance value of the bottom layer is 0Ω, the total resistance value of the shoe sole after forming the bottom layer is:
1 × 10 ⁶ Ω + 0Ω ≒ 1 × 10 ⁶ Ω
It becomes.

In any case, since the resistance value of the bottom layer is remarkably smaller than the total resistance value in the thickness direction of the shoe sole, the influence of the resistance value of the bottom layer on the total resistance value in the thickness direction of the shoe sole is extremely small.
Therefore, the antistatic shoe of the present invention can be produced with high productivity by simply laminating the bottom layer on the bottom layer of the shoe sole.
Examples of the bottom layer include a coating layer of a conductive resin composition, a vulcanized rubber sheet layer of a conductive rubber composition, or a conductive metal foil layer. Each of these bottom layers can be formed by a conventional method, and is preferable for improving the productivity of antistatic shoes.

  For example, the coating layer can be formed by applying a conductive resin composition coating to the lowermost layer of the shoe sole, drying the coating layer, and curing the resin as necessary. The vulcanized rubber sheet layer can be formed by adhering a vulcanized rubber sheet of a conductive rubber composition to the lowermost layer of the shoe sole via, for example, a conductive adhesive or a conductive double-sided tape. Further, the conductive metal thin layer is formed by fixing the metal foil to the lowermost layer of the shoe sole in a state of being in direct contact with the shoe or by adhering via the conductive adhesive, the conductive double-sided tape or the like. it can.

In particular, the bottom layer is preferably a conductive resin composition layer containing urethane resin and conductive zinc oxide in an amount of 90 to 200 parts by mass per 100 parts by mass of the urethane resin.
The layer can be formed, for example, by applying a conductive resin composition coating as described above and then drying and curing the urethane resin, and has a high conductivity of 5 × 10 ³ Ω or less. And moderate strength, and excellent flexibility required for the sole.

In the present invention, the total resistance value in the thickness direction between the outer bottom surface and the middle bottom surface of the shoe sole is set in an environment of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5% under Japanese Industrial Standard JIS C61340-4. -3 _{: 2009} (IEC 61340-4-3 _{: 2001} ) "Static electricity-Part 4-3: Standard test method for specific application-Footwear" I will do it.

In addition, the resistance value of the bottom layer itself is measured in an environment of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5% under Japanese Industrial Standard JIS C61340-4-1 _{: 2008} (IEC 61340-4-1 _{: 2003} ) 4-1: Standard test method for specific application-electrical resistance of floor finish and construction floor "shall be expressed by the value measured in accordance with the measurement method.
Furthermore, in the present invention, an antistatic shoe for comparing the human body charging potential in an environment where the human body charging potential is a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and Japanese Industrial Standard JIS T8118 _{: 2001} “Static Antistatic Workwear The test described in Japanese Industrial Standards JIS L1021-16 _{: 2007} "Fiber floor covering test method-Part 16: Chargeability-Walking test method" with the subject wearing the antistatic clothing specified in " It shall be expressed as a value measured according to the method.

According to the present invention, the resistance value of the shoe sole is maintained at a prescribed value of 10 ⁵ Ω or more to reliably prevent an electric shock due to electric leakage, and the static electricity accumulated in the worker's body can be more quickly collected than before. It is possible to provide an antistatic shoe that can be discharged to the floor to suppress the charged potential of the human body to several tens of volts or less.

It is sectional drawing which shows an example of embodiment of the antistatic shoe of this invention. It is a figure explaining the method which measured the human body electrical potential in the Example and comparative example of this invention.

FIG. 1 is a cross-sectional view showing an example of an embodiment of an antistatic shoe according to the present invention.
Referring to FIG. 1, an antistatic shoe 1 of this example includes a shoe sole 2 formed in a planar shape that can include a sole, and an upper surface of the shoe sole 2, that is, a mid-bottom surface 3 with which the sole contacts. A shoe upper body 4 formed integrally with the shoe sole 2 is provided so as to cover it.
Among the above, the shoe sole 2 has an insole 6, an insole (midsole) 7, a midsole 8, an outsole (outer sole) 9, in order from the inner bottom surface 3 to an outer bottom surface 5 that contacts a floor surface (not shown). And a bottom layer 10. Among these, the upper surface of the insole 6 is the inner bottom surface 3, and the lower surface of the bottom layer 10 is the outer bottom surface 5.

The shoe upper body 4 is formed of leather, artificial leather, synthetic resin, or the like as in the past.
The insole 6, the insole 7, the midsole 8, and the outsole 9 can be formed of the same material as the conventional one, but the total resistance value in the thickness direction from the inner bottom surface 3 to the outer bottom surface 5 is 10 ⁵ Ω as described above. As described above, the resistance value of each member is adjusted to be 10 ⁸ Ω or less.
For example, these members are formed of foamed resins such as foamed urethane resin and foamed EVA, woven fabrics and non-woven fabrics made of dedicated fibers and chemical fibers, and the foamed resins include, for example, conductive carbon black and conductive zinc oxide. Other conductive agents are blended to adjust the resistance value. In addition, the resistance value is adjusted by blending, for example, carbon fiber, metal fiber, or the like into the woven fabric or the nonwoven fabric.

The reason why the total resistance value in the thickness direction from the inner bottom surface 3 to the outer bottom surface 5 of the shoe sole 2 is limited to the above range is that if the total resistance value is less than 10 ⁵ Ω, it is impossible to prevent electric shock due to electric leakage. is there. When the total resistance value exceeds 10 ⁸ Ω, static electricity accumulated in the worker's body smoothly leaks to the bottom layer 10 in the thickness direction of the shoe sole 2 and quickly reaches the floor through the bottom layer 10. This is because it cannot be discharged.

On the other hand, if the total resistance value is in the range of 10 ⁵ Ω or more and 10 ⁸ Ω or less, the thickness of the shoe sole 2 can prevent static electricity accumulated in the worker's body while reliably preventing electric shock due to leakage. It is possible to smoothly leak to the bottom layer 10 in the direction and quickly discharge to the floor through the bottom layer 10.
In consideration of further improving these effects and providing the antistatic shoe 1 excellent in both the electrostatic discharge function and the electric shock prevention function at the time of electric leakage, the total resistance value is within the above range. However, it is preferably 10 ⁶ Ω or more, and preferably 10 ⁷ Ω or less.

The bottom layer 10 is formed continuously over the lowermost layer of the shoe sole 2, that is, substantially the entire lower surface of the outsole 9.
The bottom layer 10 needs to have a resistance value of 0Ω or more and 5 × 10 ³ Ω or less measured according to the measurement method .
When the resistance value of the bottom layer 10 exceeds 5 × 10 ³ Ω , the static electricity accumulated in the worker's body and leaked to the bottom layer 10 through the shoe sole 2 is promptly passed through the bottom layer 10 in the surface direction. This is because the effect of discharging to the floor surface from an arbitrary position of the outer bottom surface 5 cannot be obtained.

On the other hand, if the resistance value of the bottom surface layer 10 is 5 × 10 ³ Ω or less, the static electricity is quickly leaked in the surface direction through the bottom surface layer 10, so that the floor surface can be Can be discharged. That is, substantially the entire outer bottom surface 5 of the antistatic shoe 1 can function as an outlet for static electricity.
For example, as indicated by a bold two-dot chain line arrow in FIG. 1, static electricity leaked in the thickness direction of the shoe sole 2 from the inner bottom surface 3 toward the outer bottom surface 5 at the heel portion of the shoe sole 2. Through the bottom layer 10 as shown by broken arrows in the figure, to the tip of the toe of the outer bottom surface 5 and the tip of the heel, are quickly leaked in the surface direction, and the arbitrary position of the outer bottom surface 5 It is possible to discharge from the floor to the floor.

Therefore, even if it is a sink-floor type antistatic floor having uneven conductivity and scattered static electricity entrances on the floor surface, the static electricity entrance and the static electricity exit of the antistatic shoe 1 That is, the chance of contact with the substantially entire surface of the outer bottom surface 5 can be greatly increased, and the static electricity can be quickly discharged from the antistatic shoe 1 to the floor.
Therefore, as described above, the total resistance value in the thickness direction from the inner bottom surface 3 to the outer bottom surface 5 of the shoe sole 2 is set to 10 ⁵ Ω or more to prevent electric shock due to electric leakage, and the total resistance value is set to 10 ⁸ Ω or less. In combination with the ability to smoothly leak the static electricity accumulated in the worker's body to the bottom layer in the thickness direction of the shoe sole, it is possible to reliably prevent the electric shock caused by the leakage while still collecting the static electricity accumulated in the worker's body. It is possible to discharge to the floor more quickly than before, and to suppress the human body charging potential to several tens of volts or less, particularly for the sink-type antistatic floor.

The pre-Symbol bottom layer 10, for example, coating layer of the conductive resin composition, a vulcanized rubber sheet layer of a conductive rubber composition, the conductive metal foil layer. These bottom surface layers 10 can be formed by ordinary methods, respectively, and are preferable for improving the productivity of the antistatic shoe 1.

  For example, the coating layer can be formed by applying a conductive resin composition coating to the lowermost layer of the shoe sole 2 and then drying, and if necessary, curing the resin. The vulcanized rubber sheet layer can be formed by adhering a vulcanized rubber sheet of a conductive rubber composition to the lowermost layer of the shoe sole 2 via, for example, a conductive adhesive, a conductive double-sided tape or the like. Furthermore, the conductive thin metal layer is fixed to the lowermost layer of the shoe sole 2 in a state where a metal foil such as an aluminum foil is in direct contact, or through the conductive adhesive, conductive double-sided tape or the like. It can be formed by bonding.

Among these, when a conductive metal thin layer is employed as the bottom layer 10, the resistance value of the bottom layer 10 measured by the measurement method can be set to 0Ω.
In particular, the bottom layer 10 is preferably a layer of a conductive resin composition containing a urethane resin and conductive zinc oxide as a conductive agent in an amount of 150 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the urethane resin.

The layer can be formed, for example, by applying a conductive resin composition coating as described above and then drying and curing the urethane resin, and has a high conductivity of 5 × 10 ³ Ω or less. And moderate strength and excellent flexibility required for the shoe sole 2.
In addition, it is based on the following reason that the mixture ratio of electroconductive zinc oxide shall be in the said range.
That is, when the blending ratio is less than 90 parts by mass, the effect of imparting appropriate conductivity to the bottom layer 10 by blending the conductive zinc oxide becomes insufficient, and the resistance value of the bottom layer 10 is 5 × 10 ^3. May exceed Ω .

On the other hand, when it exceeds 200 parts by mass, the proportion of the urethane resin is relatively reduced, and the strength of the bottom layer 10 may be reduced, or the flexibility may be reduced.
In consideration of imparting higher conductivity to the bottom layer 10 while maintaining good strength and flexibility, the blending ratio of the conductive zinc oxide is 100 parts by mass or more even within the above range. Is preferably 150 parts by mass or less.

As the urethane resin, a one-pack room temperature curable urethane resin that does not require the labor of blending or heating is preferable. Specific examples of such a one-part room temperature curable urethane resin include C926 manufactured by Sumitomo Rubber Industries, Ltd.
As the conductive zinc oxide, for example, any of various conductive zinc oxides widely used as a conductive agent for an antistatic floor or rubber can be used. Specific examples of such conductive zinc oxide include 23-K manufactured by Hakusui Tech Co., Ltd.

The coating material of the conductive resin composition is prepared by blending the one-component room temperature curable urethane resin and conductive zinc oxide with an organic solvent such as xylene as necessary to adjust the viscosity to a predetermined level. The
The coating agent is continuously applied over substantially the entire lower surface of the outsole 9 by a coating method such as roller coating or spray coating, and the bottom layer is obtained by curing and reacting one liquid room temperature curable urethane resin. 10 is formed.

The thickness of the bottom layer 10 is 0.5 mm or more in consideration of giving the bottom layer 10 high conductivity of 5 × 10 ³ Ω or less, good durability, strength, flexibility, and the like. It is preferable that it is 2 mm or less.
The configuration of the antistatic shoe of the present invention is not limited to the example of FIG.
For example, the shoe sole 2 is not limited to the five-layer structure in the example shown in the figure, and may be formed in a structure along any layer of 2 layers or more, 4 layers or less, or 6 layers or more having the bottom layer 10 as the bottom layer. Can do.

  In addition, various design changes can be made without changing the paper of the present invention.

<Electrostatic shoes>
Examples of electrostatic shoes used as the basis for the antistatic shoes of Examples and Comparative Examples described later are ED-P / C2 compliant electrostatic shoes defined by Japanese Industrial Standards JIS T8103 [Midori Safety Co., Ltd. CF210 was used.
The electrostatic shoes are prepared in the same number as the examples and comparative examples, and the total resistance value in the thickness direction of each shoe sole is described above in an environment of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. In accordance with the measurement method stipulated in Japanese Industrial Standards JIS C61340-4-3 _{: 2009} (IEC 61340-4-3 _{: 2001} ) "Static Statics-Part 4-3: Standard Test Methods for Specific Applications-Footwear" As a result of measurement, it was found that there are two types, 3 × 10 ⁶ Ω and 4 × 10 ⁶ Ω.

< Comparative Example 1 >
(Preparation of paint)
1 part of room temperature curable urethane resin [C926 manufactured by Sumitomo Rubber Industries, Ltd.] 100 parts by mass, 100 parts by mass of conductive zinc oxide [23-K manufactured by Hakusuitec Co., Ltd.] and 50 parts by mass of xylene Thus, a coating agent for the conductive resin composition was prepared.

(Antistatic shoes)
The coating agent is applied to the bottom layer of the shoe sole of the electrostatic shoe having a total resistance value in the thickness direction of the shoe sole of 3 × 10 ⁶ Ω by a roller brush over the entire surface and dried. The antistatic shoe of Comparative Example 1 was manufactured by curing the urethane resin to form a bottom layer having a thickness of 1 mm.
< Example 1 >
A conductive resin composition coating was prepared in the same manner as in Comparative Example 1 except that the amount of conductive zinc oxide was 150 parts by mass. The total resistance in the thickness direction of the shoe sole was 4 in the coating. A bottom surface layer having a thickness of 1 mm is formed by applying a roller brush over the substantially entire surface of the bottom of the shoe of the electrostatic shoe, which is × 10 ⁶ Ω, and drying and curing the urethane resin. An antistatic shoe of Example 1 was produced.

< Example 2 >
In a state where the aluminum foil is in direct contact with the bottom layer of the shoe sole of the electrostatic shoe having a total resistance value in the thickness direction of the shoe sole of 3 × 10 ⁶ Ω over substantially the entire surface thereof, the aluminum foil Was fixed to the outer peripheral surface of the shoe sole rising from the outer bottom surface using an adhesive tape to produce the antistatic shoe of Example 2 .

< Example 3 >
(Vulcanized rubber sheet)
As the vulcanized rubber sheet, the same vulcanized rubber sheet as the resistance value measurement rubber pad (thickness: 1 mm, resistance value 100Ω) defined in Japanese Industrial Standard JIS C61340-4-1 is used. What was processed into the shape was prepared.

(Antistatic shoes)
A conductive double-sided adhesive tape covering the entire bottom surface of the shoe sole of the electrostatic shoe having a total resistance value in the thickness direction of the shoe sole of 3 × 10 ⁶ Ω over the substantially entire surface thereof. The antistatic shoe of Example 3 was manufactured by fixing via a carbon double-sided tape for SEM (aluminum substrate) manufactured by Oken Shoji Co., Ltd.

< Comparative Example 2 >
The electrostatic shoe having a total resistance value in the thickness direction of the shoe sole of 4 × 10 ⁶ Ω was used as an antistatic shoe of Comparative Example 2 as it was.
< Comparative Example 3 >
A conductive resin composition coating material was prepared in the same manner as in Comparative Example 1 except that the amount of conductive zinc oxide was 85 parts by mass. The coating material had a total resistance value of 3 in the thickness direction of the shoe sole. A bottom surface layer having a thickness of 1 mm is formed by applying a roller brush over the substantially entire surface of the bottom of the shoe of the electrostatic shoe, which is × 10 ⁶ Ω, and drying and curing the urethane resin. An antistatic shoe of Comparative Example 3 was produced.

< Comparative example 4 >
In the same manner as in Comparative Example 1 except that conductive zinc oxide was not blended, a resin composition coating material having no electrical conductivity was prepared, and the coating material had a total resistance value in the thickness direction of the shoe sole. A bottom surface layer of 1 mm in thickness is formed by applying a roller brush over the entire bottom surface of the shoe sole of the electrostatic shoe, which was 3 × 10 ⁶ Ω, and drying and curing the urethane resin. Thus, an antistatic shoe of Comparative Example 4 was produced.

<Measurement of total resistance of shoe sole>
The total resistance value in the thickness direction between the outer bottom surface and the middle bottom surface of the shoe soles of the antistatic shoes produced in Examples 1 to 3 and Comparative Examples 1 to 4 is a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5. % JIS C 61340-4-3: 2009 (IEC 61340-4-3-3: 2001) "Static-Part 4-3: Standard test methods for specific applications-Footwear The measurement was performed according to the measurement method defined in “1.

<Measurement of bottom layer resistance>
The resistance value of the bottom layer itself formed in the bottom layer of the shoe sole in Examples 1 to 3 and Comparative Examples 1 , 3 , and 4 was described above in an environment of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%. Japanese Industrial Standard JIS C61340-4-1: 2008 (IEC 61340-4-1: 2003) "Static electricity-Part 4-1: Standard test method for specific application-Electrical resistance of floor finish and construction floor The measurement was performed according to the measurement method defined in “1.

Specifically, using the coating agent used for forming the bottom layer in Example 1 , Comparative Examples 1 , 3 , and 4 , the aluminum foil used in Example 2 , and the vulcanized rubber sheet used in Example 3 The test piece for measurement defined in the test method was prepared, and the vertical resistance value (leakage resistance value) of the test piece was measured to obtain the resistance value of the bottom layer itself.
<Measurement of human body charging potential>
Antistatic shoes manufactured in Examples 1 to 3 and Comparative Examples 1 to 4 in an environment of a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5%, and Japanese Industrial Standards JIS T8118: 2001 “Static Antistatic Work Clothes” The test method described in Japanese Industrial Standard JIS L1021-16: 2007 “Fiber floor covering test method-Part 16: Chargeability—Walking test method” with the subject wearing the prescribed antistatic clothing. Accordingly, the human body charging potential was measured.

Specifically, as shown in FIG. 2, first, a conductive sink floor material (EX-300S manufactured by Sumitomo Rubber Industries, Ltd.) is applied on a grounded metal plate 11 to form a sink floor type. An antistatic floor 12 is formed. In addition, an electrometer 14 having one electrode connected to the probe 13 and the other electrode grounded is prepared.
Then, on the antistatic floor 12, the antistatic shoes manufactured in Examples 1 to 3 and Comparative Examples 1 to 4 and the antistatic clothes were worn, and the subject 15 who held the probe 13 in one hand walked. The change in potential generated at that time is recorded by the recorder 16 connected to the electrometer 14.

The walking conditions were as follows.
Walk for more than 30 seconds on a regular foot.
Walk with the thigh and floor at 45 °.
Walk at a tempo of about 100 steps / minute.
Don't slip.

As the electrometer 14, a human body electrometer MODEL KSD-4000 manufactured by Kasuga Denki Co., Ltd., to which the probe 13 is attached, was used. As the recorder 16, Memory HiCorder 8870E manufactured by Hioki Electric Co., Ltd. was used.
Those measured body charging potential is less than 20V discharge performance very good (◎), was evaluated as was the 20V than the discharge performance failure (×).

  The results are shown in Table 1.

From the results of Comparative Example 2 in Table 1, it was found that when the bottom layer was not formed in the lowermost layer of the conventional electrostatic shoe, the human body charging potential was 20 V or more, and the static electricity could not be discharged quickly. Further, from the results of Comparative Examples 1 , 3 , and 4 , even when the bottom layer is formed in the lowermost layer, when the resistance value of the bottom layer itself exceeds 5 × 10 ³ Ω , the human body charging potential is 20 V or more. After all, it was found that static electricity could not be discharged quickly.

On the other hand, from the results of Examples 1 to 3 , when a bottom layer having a resistance value of 0Ω or more and 5 × 10 ³ Ω or less is formed on the lowermost layer of the electrostatic shoe, It was found that the static charge can be discharged quickly while maintaining the total resistance value in the thickness direction of the bottom within the range of 10 ⁵ Ω or more and 10 ⁸ Ω or less while the human body charging potential is less than 20V .

DESCRIPTION OF SYMBOLS 1 Antistatic shoe 2 Shoe sole 3 Middle bottom surface 4 Upper shoe body 5 Outer bottom surface 6 Insole 7 Insole 8 Mid sole 9 Outsole 10 Bottom layer 11 Metal plate 12 Antistatic floor 13 Probe 14 Electrometer 15 Subject 16 Record meter

Claims (3)

An antistatic shoe comprising a bottom surface layer constituting the outer bottom surface of the shoe sole and extending substantially over the entire outer bottom surface , and a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 5 of the bottom surface layer itself. % JIS C 61340-4-1: 2008 (IEC 61340-4-1: 2003) "Static Static-Part 4-1: Standard Test Methods for Specific Applications-Floor Finishing Materials and The resistance measured in accordance with the measurement method specified in “Electric resistance of construction floor” is 0Ω or more and 5 × 10 ³ Ω or less, and from the inner bottom surface of the shoe sole to the outer bottom surface constituted by the bottom layer. An antistatic shoe characterized by having a total resistance value between 10 ⁵ Ω and 10 ⁸ Ω.   The said bottom layer is a coating layer of a conductive resin composition, a vulcanized rubber sheet layer of a conductive rubber composition, or a conductive metal foil layer formed in the lowermost layer of a shoe sole. Antistatic shoes.   The charging according to claim 1, wherein the bottom layer is a layer of a conductive resin composition containing a urethane resin and a conductive zinc oxide of 90 parts by mass or more and 200 parts by mass or less per 100 parts by mass of the urethane resin. Prevention shoes.

Images