EP0721760A1

EP0721760A1 - Cleaning material

Info

Publication number: EP0721760A1
Application number: EP96100419A
Authority: EP
Inventors: Masanobu Mizoguchi; Toshiki Iijima; Noboru Tanaka; Toshiaki Koyousokushinjutaku 1-304 Takase
Original assignee: Japan Vilene Co Ltd
Current assignee: Japan Vilene Co Ltd
Priority date: 1995-01-13
Filing date: 1996-01-12
Publication date: 1996-07-17
Anticipated expiration: 2016-01-12
Also published as: KR0172583B1; EP0721760B1; DE69603510D1; KR960029502A; DE69603510T2; CN1139165A; CN1077183C

Abstract

The present invention relates to a cleaning material comprising a fiber sheet which comprises conductive fibers coated with an electron conjugated polymer, wherein the adhesion ratio of the electron conjugated polymer to the fiber sheet is 0.05 to 3 weight %. The relationship between the adhesion ratio X (weight %) and the surface resistance Y (Ω/□) of the fiber sheet which comprises conductive fibers coated with an electron conjugated polymer satisfies the following formula (P) : log Y ≦ -0.8X + 5 ...... (P).

The average diameter of the fiber comprised in the fiber sheet is 10 µm or less. The present cleaning materials are suitable for cleaning objects which are liable to generate static electricity by the friction with a cleaning material, such as automobile bodies before coating, furniture including tables, desks, chests of drawers, cabinets and chairs, plastic moldings, windows, doors and floors.

Description

The present invention relates to cleaning materials suitable for cleaning objects which are liable to generate static electricity by the friction with a cloth-like cleaning material, such as automobile bodies before coating, furniture including tables, desks, chests of drawers, cabinets and chairs, plastic moldings, windows, doors and floors.
In coating an automobile body, the part to be coated should be cleaned beforehand so as to avoid inferior finishing due to the dust collected from the atmosphere and attached to the surface of the part. Although conventional cleaning sheets made of a woven fabric or a nonwoven fabric can clean the part to be coated temporarily, they are not practical since static electricity is liable to be generated by the friction between the cleaning sheets and the part to be coated, thus gathering dust from the atmosphere. Therefore an ion neutralizing device and a cloth applied with an adhesive on its surface are used together. However, the cleaning method of eliminating static electricity with an ion neutralizing device and wiping with a cloth having an adhesive property on its surface is troublesome, and besides the ion neutralizing device is expensive.
Also in cleaning furniture, plastic moldings, windows, doors or floors using conventional cleaning sheet made of a woven fabric or a nonwoven fabric, there has been the same problem that static electricity is liable to be generated and gather dust due to the friction between a cleaning sheets and the object to be cleaned and the part can be cleaned only temporarily. Thus, cleaning sheets comprising conductive fibers including carbon black or metal powders, or metal-plated conductive fibers have been used. However, there are problems in that the former is insufficient in terms of fiber strength and durability whereas the latter tends to damage the object being cleaned.
The object of the present invention is to solve the above-mentioned problems and to provide cleaning materials having excellent durability and operability without damaging the object to be cleaned nor generating static electricity.
This object has been achieved by a cleaning material comprising a fiber sheet which comprises a conductive fiber coated with an electron-conjugated polymer (a polymer having conjugated electrons), wherein the adhesion ratio of the electron-conjugated polymer to the fiber sheet is 0.05 to 3 weight %, and the relationship between the adhesion ratio X (weight %) and the surface resistance Y (Ω/□) of the fiber sheet which comprises a conductive fiber coated with an electron conjugated polymer satisfies the following formula (P) : $log Y ≦ -0.8X + 5$
and the average diameter of the fiber comprised in the fabric sheet is 10 µm or less.
The cleaning materials of the present invention comprise a conductive fiber coated with an electron conjugated polymer and the electron conjugated polymer is soft enough to avoid damaging the object to be cleaned. Also, static electricity can be eliminated by corona discharge at the time of cleaning the object to be cleaned, and cleaning can be conducted without generating static electricity on the object to be cleaned. Further, since electron conjugated polymers just cover the surface of a fiber without deteriorating the fiber strength, cleaning materials having excellent durability can be provided. Moreover, since cleaning materials of the present invention can clean and eliminate static electricity by just wiping the object to be cleaned, they provide excellent operability.
FIG. 1 is a sectional view of an embodiment of conjugated fibers capable of further generating fine fibers which are used in the present invention.
FIG. 2 is a sectional view of another embodiment of conjugated fibers capable of further generating fine fibers which are used in the present invention.
FIG. 3(a) is a sectional view of a further embodiment of conjugated fibers capable of further generating fine fibers which are used in the present invention.
FIG. 3(b) is a sectional view of another embodiment of conjugated fibers capable of further generating fine fibers which are used in the present invention.
FIG. 4 is a schematic depiction of an embodiment of an application of the cleaning materials of the present invention.
FIG. 5 is a schematic depiction of another embodiment of an application of the cleaning materials of the present invention.
FIG. 6 is a schematic depiction of a further embodiment of an application of the cleaning materials of the present invention.
Cleaning materials of the present invention comprise a fiber sheet comprising a conductive fiber coated with an electron conjugated polymer. Examples of such fibers coated with an electron conjugated polymer include natural fibers such as silk, wool, cotton and linen, regenerated fibers such as rayon fibers, semi synthetic fibers such as acetate fibers, and synthetic fibers such as polyamide fibers, polyvinyl alcohol fibers, acryl fibers, polyester fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyurethane fibers, polyethylene fibers, polypropylene fibers and aromatic polyamide fibers. Further, conjugated fibers comprising a plurality of resin components of sheath & core type or a side-by-side type can be used as well.
Cleaning materials comprising fine fibers obtained from conjugated fibers capable of further generating fine fibers having a diameter of 9 µm or less by a physical and/or a chemical treatment (hereinafter referred to as "fiber capable of further generating fine fibers") can be used preferably because such cleaning materials exhibit excellent elimination of static electricity by corona discharge, excellent cleaning of the object to be cleaned and retaining of the dust, do not tend to damage the object to be cleaned and have excellent strength. Examples of such fibers capable of further generating fine fibers include embodiments such as an island-in-sea type conjugated fiber having a section comprising a component (A) with another component (B) located therein like islands as illustrated in FIG. 1, a multiple-bimetal type conjugated fiber having a section comprising a component (A) and another component (B) laminated alternately to form layers as illustrated in FIG. 2 and an orange section-type conjugated fiber having a sectional configuration comprising a component (A) divided with another component (B) radially as illustrated in FIGs. 3(a) or 3(b). Among these embodiments, multiple-bimetal type conjugated fibers and "orange" type conjugated fibers are preferable since fine fibers yielded therefrom have a modified cross-sectional shape such as a trapezoid-like shape and a sector shape to excellently facilitate cleaning and elimination of static electricity.
Known methods can be used to yield fine fibers from such fibers capable of further generating fine fibers. Examples of common methods include physical treatment methods such as applying mechanical stress to a fiber capable of further generating fine fibers as illustrated in FIGs. 2, 3(a), 3(b) to divide components (A) and (B) at their borders to obtain fine fibers of component (A) and (B), or chemical treatment methods such as removing a component (A) with a solvent capable of dissolving only a component (A) or with a chemical capable of decomposing only a component (A) to an island-in-sea type conjugated fiber as illustrated in FIG. 1 to obtain fine fibers of the component (B). The physical treatment methods and chemical treatment methods can be used together as needed. The chemical treatment methods can be applied to fibers capable of further generating fine fibers as illustrated in FIGs. 2, 3(a), 3(b) to obtain fine fibers of one component. Also the physical treatment methods can be applied to island-in-sea type conjugated fibers as illustrated in FIG. 1 in case the sea component (A) comprises a resin component pulverizable by a mechanical stress.
Resin components of such fibers capable of further generating fine fibers may be a combination of two or more. Examples of a combination of two components include a polyamide resin and a polyester resin, a polyamide resin and a polyolefin resin, a polyester resin and a polyolefin resin, polyester resin and a polyacrylonitrile resin, a polyamide resin and a polyacrylonitrile resin, and a polyolefin resin and a polyacrylonitrile resin.
It is preferable that a fiber sheet comprising a cleaning material contains 5 weight % or more of fine fibers yielded from such fibers capable of further generating fine fibers. Since the greater the content of fine fibers, the better both the static electricity elimination property and the wiping property of the cleaning material become, it is more preferable that the ratio of fine fibers yielded from the fibers capable of further generating fine fibers is 50 weight % or more, and it is most preferable that the ratio is 90 weight % or more.
As to the diameter of fibers comprising a fiber sheet used in the present invention, it is necessary to have the average fiber diameter of 10 µm or smaller. If the average fiber diameter is greater than 10 µm, it is impossible to provide sufficient static electricity elimination property or wiping property. Since good static electricity elimination property and wiping property can be provided without deterioration of mechanical strength or durability with the average fiber diameter in the range of 10 to 0.1 µm, it is preferable. When a fiber having a modified cross-sectional shape is used, the diameter of the round shape which has a sectional area the same as that of the modified cross-sectional shape is calculated, and the value is referred to as the "fiber diameter" herein.
The length of fibers which constitute a fiber sheet is, in general, 1 to 160 mm. It is particularly preferable to have the average fiber length in the range of 20 to 110 mm, since a shorter length may cause the problem of a tendency toward falloff of fibers, or a longer length may cause the problem of deterioration of property of eliminating static electricity due to a reduced number of ends of fibers in the fiber sheet.
The "average fiber diameter" and the "average fiber length" herein denote the average value of 100 fibers collected by random sampling.
A drawn fiber is used preferably as the fibers for the fiber sheets with respect to durability. As to the drawing ratio, 1.5 to 5 times is preferable.
A conductive fiber is formed by coating the above mentioned fibers with an electron conjugated polymer. If a fiber sheet is formed after coating fibers with an electron conjugated polymer, the electron conjugated polymer may be damaged at the time of the fiber sheet formation. Therefore it is preferable to coat a fiber with an electron conjugated polymer after forming a fiber sheet. In this case, a conductive fiber not completely coated with an electron conjugated polymer may be formed.
The adhesion ratio of an electron conjugated polymer to a fiber sheet needs to be 0.05 to 3 weight %. It is not preferable to have an adhesion ratio of smaller than 0.05 weight %, because the static electricity eliminating property of the obtained cleaning material may deteriorate. Further, it is not preferable to have an adhesion ratio of more than 3 weight %, because the flexibility of the obtained cleaning material may deteriorate to ruin the cleaning operability and the electron conjugated polymer becomes liable to fall off due to the friction against the object to be cleaned.
The adhesion ratio X (weight %) of the electron conjugated polymer to a fiber sheet is represented by the following formula: $Adhesion ratio X (weight %) = ((electron conjugated polymer weight)/(electron conjugated polymer weight + fiber sheet weight)) × 100.$
Hereinafter the case of producing cleaning materials of the present invention by forming a fiber sheet followed by coating with an electron conjugated polymer is described.
Examples of fiber sheets for cleaning materials of the present invention include nonwoven fabrics, woven fabrics and knit fabrics. Among these examples, nonwoven fabrics are preferable because static electricity can be well eliminated by corona discharge by increasing the number of fiber ends at the surface of the fabric by orienting the fibers in the direction of the thickness, and by holding a three-dimensional space, dust gathered from the object to be cleaned can be retained in the space. Such nonwoven fabric with the fibers oriented in the thickness direction thereof can be obtained by methods such as preparing a fiber web by a wet method and a dry method including a carding process and an air-laid process, or a direct method including a spun-bonded process and a melt-blown process, followed by an entangling treatment with a fluid flow such as water or a mechanical force such as a needle punching. Since the former fluid flow entangling treatment provides a nonwoven fabric superior with respect to uniformity and strength, it is more preferable. In preparing a fiber web by a carding process, it is more preferable to include a cross-laid web cross-layered with respect to the longitudinal direction of the fiber web so as to improve the strength in the width direction of the fiber web, and thus cleaning materials having an excellent shape stability and operability can be provided.
Since fine fibers can be both obtained and also entangled if the above mentioned mechanical force such as a fluid flow or a needle punching is applied to a fiber web containing the above mentioned multiple-bimetal type conjugated fibers or orange type fibers capable of further generating fine fibers without the need of having a further process to yield fine fibers, such method of forming a nonwoven fabric is efficient. Further, since entanglement of fine fibers provides a dense structure, dust can be retained well.
It is preferable to improve strength and wearing resistance property of a nonwoven fabric by fixing with a binder of an emulsion-type, a solution-type or a powder-type, or by heat-binding intersections of fibers of the nonwoven fabric. However, in order not to deteriorate the static electricity elimination property or wiping property, it is preferable to fix partially. In the case a nonwoven fabric is fixed partially, it is preferable that the area per one fixed part is 0.01 to 5 mm² and the total fixed area based on the total area (the area observed two-dimensionally as if the surface of the nonwoven fabric is flat) of the nonwoven fabric is 5 to 50 % with respect to the improvement of strength and wear resistance property by the fixation without deteriorating the static electricity elimination property or wiping property. Among methods of fixation, methods of partially fixing a nonwoven fabric by means of an embossing roll or an ultrasonic wave is more preferable since they do not cause falloff of a binder during the use of the cleaning material, unlike a nonwoven fabric fixed with a binder, to provide an excellent cleaning property.
Further, in order not to further deteriorate the property of eliminating static electricity, a layered fiber web having two layers or a three layers structure can be formed by a heat treatment with a fiber web containing heat-adhesive fibers on one side or as the middle layer.
In the case a nonwoven fabric is formed by entangling fibers of a fiber web by a fluid flow such as a water flow, by introducing a support such as a coarse net of ca. 0.29 mm opening (50 mesh) or larger made of metal or plastic and a corresponding porous plate, the water flow is reflected at parts where the net or porous plate exists, and since fibers are pushed aside by the reflected water flow at parts where the net or porous plate exists as well as entangle with each other, perforations are formed through the thickness direction of the fiber sheet at the parts corresponding to the parts where the net or porous plate exists. Hereinafter a nonwoven fabric formed in such manner is referred to as a "nonwoven fabric having perforations". The nonwoven fabrics having perforations have a structure that the entangled fiber bundles are crossed with each other, and fiber bundles entangle at points of intersections. Since the nonwoven fabrics having perforations collect dust from the side walls of the perforations and keep them inside of the sheet, they have an advantage of the excellent dust retention property. In the case such perforations are formed in a nonwoven fabric by a water flow, the producing conditions are not particularly limited except the support. For example, nonwoven fabrics having perforations can be formed by jetting water flow one or more times to one side or both sides of the fiber web from a nozzle plate with nozzles having a diameter of 0.05 to 0.3 mm, located with an interval of 0.2 to 3 mm aligned in a row or in a plurality of rows regularly or irregularly. The jetting pressure of the water from nozzles can be about 1 to 30 MPa (10 to 300 kg/cm²).
Since fiber sheets used in the present invention are porous, almost the entire region of a fiber sheet can be coated with an electron conjugated polymer. Since the electron conjugated polymers can adhere tightly to a fiber sheet, they provide excellent durability. Further since they are very flexible, wiping and static electricity elimination can be conducted without damaging the object to be cleaned.
It is preferable to have a 10 % modulus strength for the obtained cleaning materials of the present invention of 0.5 Kg/5 cm width or more in both the longitudinal direction and widthwise direction with the above mentioned various processing methods of fiber sheets to provide an excellent shape retention property and operability of the cleaning material in use. From this viewpoint, nonwoven fabrics formed by laminating a parallel web in which fibers are oriented to the longitidinal direction of the fiber web and a cross-laid web in which fibers are crossed by a cross-layer, and the above mentioned nonwoven fabrics having "perforations" are particularly preferable.
It is preferable in the present invention that the surface resistance of a cleaning material obtained by coating an electron conjugated polymer is approximately 1 × 10⁵ Ω/□ or less because a surface resistance over 1 × 10⁵ Ω/□ deteriorates the property of eliminating static electricity. It is more preferable that the surface resistance is 1 × 10⁴ Ω/□ or less.
Examples of coating methods with an electron conjugated polymer include a method of applying to a fiber sheet a solution containing an oxidant which is a polymerization catalyst such as ferric chloride (FeCl₃) and cupric chloride (CuCl₂) followed by contacting with a raw monomer for polymerization, and a method of first applying a raw monomer to a fiber sheet followed by contacting with a solution containing an oxidant which is a polymerization catalyst such as ferric chloride (FeCl₃) and cupric chloride (CuCl₂). As a method of contacting with a monomer, when the monomer is in the liquid state, the monomer can be applied to a fiber sheet by soaking, coating or spraying. When the monomer is in the gas state, a fiber sheet can be placed in a container filled with the monomer gas. Polymerization catalysts can be applied to or contacted with a fiber sheet by soaking, coating or spraying.
Examples of such monomers which can form electron conjugated polymers include acetylene, benzene, aniline, phenyl acetylene, pyrrole, furan, thiophene, indole and derivatives of these monomers having at least one substituent selected from the group consisting of allyl, aryl and alkyl. Among these examples, pyrrole is preferable since it has an excellent conductivity and polymerizing property, and an excellent static electricity eliminating property and durability.
What is important here is that the relationship between the adhesion ratio X (weight %) and the surface resistance Y (Ω/□) of the fabric sheet which comprises a conductive fiber coated with an electron conjugated polymer satisfies the following formula (P) : $log Y ≦ -0.8X + 5$
The formula (P) suggests that if too much of the electron conjugated polymer is adhered, flexibility of the obtained cleaning material deteriorates to lower the cleaning ability and further the electron conjugated polymer tends to fall off due to the friction against the object to be cleaned, which is not preferable. Thus a smaller adhesion amount is preferable, but in this case, an electron conjugated polymer having a good conductivity to satisfy the condition stipulated in the formula (P) should be used so as not to allow the surface resistance Y of the cleaning material to become too large.
In general, as the molecular weight becomes greater, in other words as the polymer chain becomes longer, surface resistance value of cleaning material becomes lower. Besides, the falloff of an electron conjugated polymer caused by the friction against the object to be cleaned during the use of the cleaning material can be prevented. In order to obtain an electron conjugated polymer having a large molecular weight, it is not preferable to immediately wash to remove the unreacted monomer or oxidant after applying to a fiber sheet a solution containing an oxidant which is a polymerization catalyst and contacting it with a monomer, or after applying a monomer to a fiber sheet and contacting it with a solution containing an oxidant which is a polymerization catalyst. But by leaving for one minute or more, preferably for two minutes or more, further preferably for five minutes or more for polymerization, a polymer having a molecular weight sufficient to satisfy the relationship defined in the above mentioned formula (P) can be obtained. As to the temperature during the polymerization for one minute or more, preferably for two minutes or more, further preferably for five minutes or more, room temperature or below is further preferable.
Although static electricity can be eliminated better by entirely coating the fiber sheet with an electron conjugated polymer, in the case when the relationship defined in the above mentioned formula (P) is satisfied and purposes of the present invention can be fulfilled, a fiber sheet can be coated partially. When a fiber sheet is partially coated, the "surface resistance" refers to the surface resistance of the part coated with an eletron conjugated polymer.
Cleaning materials of the present invention can be used in a sheet form or in other optionally formed shapes. For example, by forming a bag-like space from a sheet of a cleaning material of the present invention, a cleaning material facilitating cleaning with an excellent operability can be provided. Examples of such a bag-like space include a glove shape to which the thumb and each of the other four fingers of a person can be inserted separately as illustrated in FIG. 4, a mitten shape to which the thumb and four fingers of a person can be inserted separately as illustrated in FIG. 5, and a shape with a glove and an integral conductive fiber sheet as illustrated in FIG. 6. Further, a space can be not only a space to insert a hand but a space to insert a mop or a foot can be applied as well.
When a cleaning material of the present invention is formed in a glove shape, the above mentioned conductive fiber sheets need to be applied in at least one side of the cleaning material so that the conductive fiber sheet side comes in contact with an object to be cleaned for cleaning without generating static electricity. It is more preferable to apply the above mentioned conductive fiber sheet to both sides so that both sides of the glove can be used in cleaning for long time usage.
A bag-like space can be formed by sewing a conductive fiber sheet or by utilizing the adhesive property of the fibers comprising the conductive fiber sheet. In the former case, a conductive thread can be used for stitching to provide further improved conductivity. Further, conductivity can be provided by coating with an electron conjugated polymer after forming a bag-like space with a fiber sheet.
As heretofore mentioned, since cleaning materials of the present invention have excellent properties for cleaning and eliminating static electricity without damaging the object to be cleaned, they are suitable for cleaning objects at which static electricity tends to generate by friction, such as automobile bodies before coating, furniture including tables, desks, chests of drawers, cabinets and chairs, plastic moldings, windows, doors and floors.
Although Examples of the present invention will be described hereinafter, this invention is not limited to these embodiments. The surface resistance is a value measured by "LORESTA AP MCP-T400" commercially available from MITSUBISHI PETROCHEMICAL COMPANY, LTD.

(Example 1)

A fiber capable of further generating fine fibers having an "orange" type section with a polyester component (A) divided with a polyamide component (B) in eight sectors from the center of the fiber toward the fiber surface radially as illustrated in FIG. 3(a) having the drawing ratio of 3 times, the size of 2 denier and the length of 38 mm, which can generate fine fibers comprising polyester component with a diameter (i.e. the diameter of the circle having the same area of the section; the same is applied hereinafter) of 4.2 µm and fine fibers comprising polyamide component with a diameter of 3.1 µm was used as the material of a fiber web. By carding the fibers, a parallel web was prepared. And by laminating a cross-laid web comprising a web same as the parallel web oriented in the crossing direction on the parallel web by cross-layer in a weight ratio of 1 : 4, a laminated fiber web was obtained. The laminated fiber web was placed on a support comprising 0.177 mm metal net and entangled by a water jet from a nozzle plate having a diameter of 0.15 mm and an interval of 0.6 mm with a pressure of 9.3 MPa to obtain a nonwoven fabric with a weight per square meter of 85 g/m² and a thickness of 0.4 mm. The nonwoven fabric was soaked in a 30 weight % ferric chloride aqueous solution, and then contacted with a pyrrole monomer gas obtained by evaporating a pyrrole solution and left for five minutes at room temperature for polymerization. Afterwards the nonwoven fabric was washed to eliminate the unreacted pyrrole and oxidant, and dried to obtain a cleaning material having the entire region covered with 2.4 g/m² of polypyrrole with an adhesion ratio of 2.7 weight % and having a surface resistance of 200 Ω/□ (≦ 692 Ω/□). The 10 % modulus strength of the cleaning material was 5.2 kg/5 cm width in the longitudinal direction and 1.2 kg/5 cm width in the widthwise direction.

(Example 2)

A nonwoven fabric obtained by the same process as Example 1 was partially adhered by passing through embossing rolls having many protrusions, with the area per protrusion being 0.25 mm² and the total area of protrusions in the embossing roll being 16 %, at 185 °C under a linear compression of 60 kg/cm to obtain a partially adhered nonwoven fabric having a weight per square meter of 85 g/m² and a thickness for the non-adhered part of 0.4 mm. Then the entire region of the partially adhered nonwoven fabric was coated with 2.4 g/m² of polypyrrole with the adhesion ratio of 2.7 weight %, and a cleaning material having a surface resistance of 200 Ω/□ (≦ 692 Ω/□) was obtained. The 10 % modulus strength of the cleaning material was 5.6 kg/5 cm width in the longitudinal direction and 1.2 kg/5 cm width in the widthwise direction.

(Example 3)

A nonwoven fabric obtained by the same process as Example 1 was soaked in water and contacted with a pyrrole monomer gas obtained by evaporating a pyrrole solution followed by soaking in 10 weight % concentration ferric chloride (III) aqueous solution and left for five minutes at room temperature for polymerization. Afterwards the nonwoven fabric was washed to eliminate the unreacted pyrrole and oxidant, and dried to obtain a cleaning material having the entire region covered with 0.8 g/m² of polypyrrole with an adhesion ratio of 0.93 weight % and having a surface resistance of 1,000 Ω/□ (≦ 18,030 Ω/□). The 10 % modulus strength of the cleaning material was 5.2 kg/5 cm width in the longitudinal direction and 1.2 kg/5 cm width in the widthwise direction.

(Comparative Example 1)

A nonwoven fabric obtained by the same process as Example 1 was soaked in 30 weight % concentration ferric chloride aqueous solution and contacted with a pyrrole monomer gas obtained by evaporating a pyrrole solution. Then it was washed immediately to eliminate the unreacted pyrrole and oxidant followed by drying to obtain a cleaning material having the entire region covered with 2.4 g/m² of polypyrrole with an adhesion ratio of 2.7 weight % and having a surface resistance of 850 Ω/□ (≧ 692 Ω/□). The 10 % modulus strength of the cleaning material was 5.2 kg/5 cm width in the longitudinal direction and 1.2 kg/5 cm width in the widthwise direction.

(Comparative Example 2)

A nonwoven fabric having a weight per square meter of 85 g/m² and a thickness of 0.8 mm was obtained by the same process as Example 1 except that a polyester fiber having a round section diameter of 12.4 µm, a length of 38 mm and a drawing ratio of 3 times was used. Then in the same process as Example 1 the entire region of the nonwoven fabric was coated with 2.4 g/m² of polypyrrole with an adhesion ratio of 2.7 weight % and a cleaning material having a surface resistance of 410 Ω/□ (≦ 692 Ω/□) was obtained. The 10 % modulus strength of the cleaning material was 5.7 kg/5 cm width in the longitudinal direction and 0.2 kg/5 cm width in the widthwise direction.

(Static electricity elimination test)

A polyimide film was wiped back and forth for five times with a cleaning material of Examples 1 to 3 and Comparative Examples 1 to 2 respectively, and the static voltage of the polyimide film was measured in accordance with the JIS Standard, L1092 reference method, with a friction static voltage testing device "EST-7" commercially available from Kanebo Engineering, Ltd. The measurement was conducted under a temperature of 20 °C and humidity of 50 %. The results are as follows.

Example 1 : 0.3 KV

Example 2 : 0.5 KV

Example 3 : 1.2 KV

Comparative Example 1 : 1.2 KV

Comparative Example 2 : 1.5 KV

(Wearing resistance test)

Cleaning materials of Examples 1 to 3 and Comparative Examples 1 to 2 were rubbed for 200 times respectively with a 20 g/cm² load with an appearance-retention type tester according to the C method complying with JIS-L-1076, and the wearing resistance property was evaluated by visual inspection. After the wearing resistance test, the static electricity elimination properties of these cleaning materials were also evaluated in the same manner as the above mentioned. ("JIS" is the abbreviated name for the Japanese Industrial Standard.)
According to the standard stipulted in the JIS-L-1076 (C method), superiority of the wearing resistance is in the order of N > L > M > H.
Since cleaning materials of the present invention comprise a fiber sheet having an average fiber diameter of 10 µm or smaller containing conductive fibers coated with an electron conjugated polymer, they can clean and eliminate static electricity of the objects to be cleaned without damaging the objects. Cleaning materials of the present invention also have an excellent durability. Further, since cleaning materials of the present invention enable cleaning and eliminating static electricity at the same time by only wiping, they provide an excellent operability.
With a fiber sheet comprising conductive fine fibers obtained from conjugated fibers capable of further generating fine fibers coated with an electron conjugated polymer, cleaning materials having better cleaning property, static electricity eliminating property and dust retention property can be provided, and if the fine fibers have a modified cross-sectional shape, a further improved cleaning property and static electricity eliminating property can be provided.
Therefore cleaning materials of the present invention are highly effective for cleaning objects which are liable to generate static electricity by the friction with a cleaning material, such as automobile bodies before coating, furniture including tables, desks, chests of drawers, cabinets and chairs, plastic moldings, windows, doors and floors.

Claims

A cleaning material comprising a fiber sheet which comprises conductive fibers coated with an electron conjugated polymer, wherein the adhesion ratio of the electron conjugated polymer to the fiber sheet is 0.05 to 3 weight %, and the relationship between the adhesion ratio X (weight %) and the surface resistance Y (Ω/□) of the fiber sheet which comprises conductive fibers coated with an electron conjugated polymer satisfies the following formula (P) : $log Y ≦ -0.8X + 5$
and the average diameter of the conductive fibers is 10 µm or less.
The cleaning material according to claim 1, wherein the conductive fiber coated with an electron conjugated polymer is a conductive fiber prepared by coating a fine fiber that was obtained from a fiber capable of further generating fine fibers with an electron conjugated polymer.
The cleaning material according to claim 2, wherein the fine fiber obtained from a fiber capable of further generating fine fibers has a modified cross-sectional shape.
The cleaning material according to any of claims 1 to 3, wherein the fiber sheet is a nonwoven fabric comprising fibers having an average fiber length of 20 to 110 mm.
The cleaning material according to any of claims 1 to 4, wherein the fibers which comprise the fiber sheet are drawn fibers.
The cleaning material according to any of claims 1 to 5, wherein the 10 % modulus strength is 0.5 Kg/5 cm width or more in both longitudinal direction and widthwise direction.
The cleaning material according to any of claims 1 to 6, wherein the fiber sheet is a laminated nonwoven fabric comprising laminated parallel web and a cross-laid web.
The cleaning material according to any of claims 4 to 7, wherein the nonwoven fabric has partially fixed portions.
The cleaning material according to any of claims 1 to 8, wherein the electron conjugated polymer is selected from polymers of acetylene, benzene, aniline, phenylacetylene, pyrrole, furan, thiophene and derivatives thereof.