JP2004251373A - Roll, sheet rolled body manufacturing method and sheet take-up device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber roll as a contact pressure roll to be used in taking up a sheet into a rolled body, having a lower friction coefficient and less aging effects. <P>SOLUTION: The rubber roll has a diamond like carbon film formed on the surface. Its surface has a static friction coefficient of 0.3 or less and a hardness of 30-70 degrees. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a roll-wound sheet (hereinafter referred to as a sheet roll body) without a winding defect such as wrinkles or a charging defect due to static electricity, and an apparatus used therefor.
[0002]
[Prior art]
When winding a sheet such as a plastic film into a roll, it is important that the sheet be wound without any winding defects such as wrinkles and charging defects due to static electricity. Generally, when a sheet is wound, in order to remove the air and wind the sheet roll body in a well-wound form, the contact pressure roll is pressed against the sheet roll body wound up to that time and wound. At this time, as the contact pressure roll, since it is necessary to remove air by following minute irregularities of the sheet roll body due to uneven thickness of the sheet, for example, silicone or urethane having a lower hardness than the metal roll is used. In many cases, a rubber roll having the above rubber wound around a core is used.
[0003]
At this time, the rubber roll is required to have a low friction rubber surface in order to suppress wrinkles and electrostatic charging of the wound sheet roll.
[0004]
On the other hand, in general, the surface of the rubber is polished and finished. For example, the surface of the rubber is treated with a chemical solution as shown in Patent Document 1, or by ultraviolet irradiation as shown in Patent Document 2. It is known to perform surface treatment.
[0005]
However, these chemical treatments and ultraviolet treatments are limited to the types of rubbers that can be treated due to the nature of chemical treatments, and are not necessarily effective for all rubbers. In general, the properties of rubber materials change over time because their surfaces are soft. For example, if a rubber material is used for a long time as a contact pressure roll, the surface treatment layer may be worn out, and the initial surface state may be reduced. There is a problem that is not maintained. In addition, additives such as softeners, plasticizers, heat stabilizers, antioxidants, conductive agents, and process oils contained in rubber, as well as unreacted monomers and oligomers, gradually seep out to the surface. In addition, there have been problems that the surface of the rubber changes, the friction coefficient and the rubber hardness change, and cracks occur.
[0006]
Preferred examples of the internal structure of the contact pressure roll used for the above purpose (particularly, the structure corresponding to the “core” of the present invention) are disclosed in Patent Documents 3 and 4.
[0007]
Patent Documents 5 to 7 disclose examples of a method for forming a “layer composed of a large number of small regions” in the present invention described later.
[0008]
[Patent Document 1]
JP-A-11-218121
[Patent Document 2]
JP 09-197801 A
[Patent Document 3]
Japanese Patent Publication No. 6-45410
[Patent Document 4]
Japanese Patent No. 2888139
[Patent Document 5]
JP 10-35418 A
[Patent Document 6]
JP-A-10-130428
[Patent Document 7]
JP-A-2002-121669
[Problems to be solved by the invention]
A first object of the present invention is to provide a roll having surface characteristics particularly suitable for manufacturing a sheet roll body and having little change over time even when used for a long time, in view of the above-mentioned problems of the prior art. It is in.
[0016]
A second object of the present invention is to provide a winding device using this roll as a contact pressure roll, and a method for manufacturing a good quality sheet roll body using such a device.
[0017]
[Means for Solving the Problems]
According to the present invention, there is provided a roll having a surface static friction coefficient of 0.3 or less and a hardness in the range of 30 to 70 degrees.
[0018]
According to a preferred embodiment of the present invention, a layer of a material softer than the material forming the core is formed on a side surface of the substantially cylindrical core, and a large number of small areas are rolled on the surface of the layer of the soft material. A roll provided with a layer formed independently in an in-plane direction is provided.
[0019]
Further, according to a preferred aspect of the present invention, there is provided a roll, wherein the plurality of small regions include a carbon film.
[0020]
Further, according to a preferred embodiment of the present invention, there is provided a roll wherein the soft material contains at least one of chloroprene-based, urethane-based, chlorosulfonated polyethylene-based, and silicone-based rubbers.
[0021]
Further, according to a preferred embodiment of the present invention, there is provided a roll, wherein the layer composed of the plurality of small regions has a thickness of 10 nm to 3 μm.
[0022]
According to a preferred embodiment of the present invention, there is provided a roll wherein the core is made of a material containing FRP using carbon fiber as a reinforcing material.
[0023]
According to another aspect of the present invention, there is provided a sheet winding device comprising the above-mentioned roll as a contact pressure roll.
[0024]
Further, according to a preferred embodiment of the present invention, there is provided a method of manufacturing a sheet roll body, which winds a sheet using a winding device and forms a sheet roll body.
[0025]
In the present invention, examples of the sheet include a web such as a plastic film, a cloth, and paper. In particular, plastic films such as polyethylene terephthalate film, polyethylene naphthalate film, polypropylene film, polystyrene film, polycarbonate film, polyimide film, polyphenylene sulfide film, nylon film, aramid film, and polyethylene film have high insulation properties and suppress charging defects. From the aspect, it is also suitable as an object of the present invention.
[0026]
In the present invention, the "static coefficient of friction" of the roll is determined by using a Hayden (HEIDON) type friction measurement method with a polyethylene terephthalate film "Lumirror" manufactured by Toray Co., Ltd. having a thickness of 6 μm and a center line average surface roughness SRa of 20 nm. The value measured by friction. The center line average roughness SRa value of the film is a value corresponding to Ra defined in JIS B0601, and a light stylus type three-dimensional roughness meter (ET-30HK) manufactured by Kosaka Laboratories is used. The measurement direction is the width direction, the cutoff value is 0.08 mm, the measurement length is 0.1 to 0.25 mm, the feed pitch is 0.2 μm, the measurement speed is 20 μm / s, and the number of measurement lines is 100. In addition, as a device for measuring the coefficient of static friction, a tribo gear TYPE 94i manufactured by HEIDON is used. The polyethylene terephthalate film is attached to the measuring slider of the measuring instrument, and the measuring instrument is pressed against the side surface of the roll (the part used for the purpose of the roll) where the axial direction is set to be horizontal. Is performed five times, and the average value of the displayed static friction coefficient is obtained.
[0027]
In the present invention, the “substantially cylindrical core” refers to a core material in which the inner shape on which a layer of a soft material is formed has a substantially cylindrical surface shape. The inside of the core material may be hollow or solid. Examples of the case where the inside is hollow are the cases described in Patent Documents 3 and 4. In particular, in the case of Patent Document 4, the main material is FRP (fiber reinforced plastic) using carbon fiber as a reinforcing material, and has a configuration suitable as a contact pressure roll. Here, the “substantially cylindrical” means a cylindrical shape or a substantially cylindrical shape as a whole, but a shape whose diameter slightly changes depending on an axial portion. This includes a crown shape in which the diameter in the axial center is larger than both ends, and an inverted crown shape in which the diameter in the axial center is smaller than both ends. The core may have a multilayer structure laminated in a radial direction. The surface may be smooth, but may not be so, and grooves and irregularities may be formed.
[0028]
In the present invention, the “material forming the core” refers to a material forming the surface of the core. Preferably, metals such as iron, SUS, and aluminum, and FRP using carbon fiber as a reinforcing member are preferably used.
[0029]
In the present invention, “soft material” refers to a material that is softer than “material forming a core”. Preferably, a rubber-based material containing at least one of chloroprene-based, urethane-based, chlorosulfonated polyethylene-based, and silicone-based rubbers is used, but any material having an appropriate hardness may be used. Note that the soft material layer may be a layer in which a plurality of material layers are laminated in the radial direction. The surface of this layer also preferably has a substantially cylindrical shape. Like the “core”, a crown shape, an inverted crown shape, or the like is used depending on the purpose. Further, the surface does not necessarily have to be smooth, and grooves and irregularities may be formed. The comparison of the softness with the material forming the core is performed by a measuring method specified in JIS K6253 type A. A JIS spring-type hardness tester stipulated in this standard is placed horizontally on the side of a "core-forming material" or "soft material" that is placed so that the axial direction is horizontal, and a load of 1 kg weight is applied. Read the hardness display when applying. The value is measured at any five points in the portion used according to the purpose of the roll, and the average value is used.
[0030]
In the present invention, "a large number of small areas are formed independently in the in-plane direction of the roll surface" means that the roll surface is divided into a large number of small areas, and a hard material integrated into each of the small areas. When a soft material is deformed by applying pressure in the normal direction of the surface from the outside, each small area follows the deformation of the soft material independently of the adjacent small area. It means that it is formed so that it can move. Patent Documents 3 and 4 disclose examples of this structure in which an amorphous carbon film treatment is applied to a rubber surface.
[0031]
In the present invention, the “thickness of a layer composed of a large number of small areas” refers to an average thickness in an area used by a method suitable for the purpose of a roll of a hard material surface layer. This thickness was determined by observing a cross section (a plane including the radial direction of the roll) of the “soft material layer” including the “layer composed of many small regions” cut out from the roll with a microscope. When the thickness of the "layer composed of a large number of small regions" is large, it may be observed with an optical microscope, and when the thickness is small, it may be observed with a scanning electron microscope (SEM). Five samples are cut out from arbitrary positions in the rotation direction and the axial direction of the roll, and the average value is used as a measured value. However, in the case of a grooved roll, the measurement is performed at a portion having no groove.
[0032]
In the present invention, “carbon film treatment” refers to a treatment for forming a hard carbon film on the surface of a flexible material. For example, by using plasma CVD (chemical vapor deposition) using a hydrocarbon gas such as methane, acetylene, and ethylene, a hard film can be formed on a layer of a soft material such as rubber. it can. This coating is often amorphous. In addition, in the present invention, since it is formed on the surface of a relatively soft material, it is preferable to have a structure that can follow the deformation of the surface of the soft material. In addition, as a means for forming such a film, a method such as a sputtering method, an ion beam method, or an ion plating method can be used in addition to the above-described plasma CVD method. This film may be called a “diamond-like carbon film (DLC film)”. Such a carbon film has a feature that the coefficient of static friction on the surface is much smaller than that of rubber and the like, and that it has high durability because it is strong against abrasion.
[0033]
In the present invention, “hardness” is measured by a measurement method specified in JIS K6253 type A. A JIS spring-type hardness tester specified by this standard is placed horizontally on a roll in which the axial direction is left horizontally, and a hardness display when a load of 1 kg weight is applied is read. The value is measured at any five points, and the average value is used. However, in the case of a grooved roll, the measurement is performed at a portion having no groove.
[0034]
FIG. 2 is an example schematically showing the configuration of a film forming apparatus for performing a carbon film treatment on the surface of a roll having a layer of a flexible material such as rubber by a plasma CVD method. In FIG. 2, the vacuum container 10 is depressurized by a vacuum exhaust mechanism 11. A rubber roll 12 for performing surface treatment is set inside the vacuum vessel 10 together with a rotation driving unit 13. Electric power is supplied from a power supply 15 to the plasma generating electrode 14 to convert the hydrocarbon-based gas supplied from the gas introduction pipe 16 into plasma. While rotating the roll at a speed of 1 to 10 rpm, a carbon film having a predetermined thickness is formed on the rubber roll surface. At this time, the core of the rubber roll 12 uses iron, is electrically grounded, and the AC power from the power supply 15 generates plasma between the rubber roll 12 and the plasma generating electrode 14 through the rubber layer. A counter electrode may be provided, and plasma generation by DC power is also possible. In forming the carbon film, it is not always necessary to rotate the roll continuously. For example, the carbon film can be formed by dividing the roll several times in the circumferential direction.
[0035]
As a method of forming a carbon film on a rubber roll, other than the method of forming a carbon film directly on a rubber roll as described above, after forming a carbon film on a sheet-like or ribbon-like rubber, Alternatively, it is also possible to form a carbon film rubber roll by winding a rubber ribbon around a rubber roll having a core or a base rubber layer. In this case, the film forming apparatus is preferable because a roll rotating mechanism is not required and the film forming apparatus can be downsized.
[0036]
If the thickness of the layer composed of a large number of small regions is too small, it is difficult to form a film having a uniform thickness, resulting in an island-like film. On the other hand, if the film is too thick, the thermal load on the rubber at the time of film formation becomes large, causing deterioration of the rubber, or the flexibility of the layer composed of a large number of small regions is inferior, so that 10 nm to 3 μm is desirable. More preferably, it is 100 nm to 1 μm.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a rubber roll using rubber as a “soft material” as an example. Note that the present invention is not limited to this.
[0038]
FIG. 1 is a cross-sectional view schematically showing a configuration of the rubber roll of the present embodiment in a plane orthogonal to the roll axis direction. In FIG. 1, a rubber roll 1 has a rubber layer 3 wound around a core 2 and an amorphous carbon film (hereinafter abbreviated as diamond-like carbon film, DLC film) 4 formed on the surface of the rubber layer 3. is there. Further, the surface of the rubber layer 3 is surface-treated by physical means such as polishing, chemical means using a chemical solution, optical means using ultraviolet rays or the like, and electrical means using discharge or plasma. Is also good. The DLC film 4 uses a method disclosed in Patent Document 5 or Patent Document 6, and in particular, since the rubber as the base material has flexibility, the DLC film 4 is formed so as to follow the flexibility of the rubber. The film is formed in a form divided into a number of small regions by cracks.
[0039]
FIG. 2 is a side view schematically showing a configuration used in an embodiment in which a rubber roll is used as a contact pressure roll for winding a sheet. In FIG. 2, the take-up core 10 is taken up by being rotated by a driving unit (not shown) to form a sheet roll body 21. The rubber roll 1 described with reference to FIG. 1 is rotatably supported below the swing arm 22 as a contact pressure roll, and the swing arm 22 is pivotally supported at its upper end by a pivot shaft 23 so as to be swingable. . A hydraulic cylinder 24 is connected to an intermediate portion of the swing arm 22. The hydraulic cylinder 24 is urged toward the sheet roll body 21 by the action of the hydraulic cylinder 24, and presses the lower rubber roll (contact pressure roll) 1 against the sheet roll body 21. ing. Since the rubber roll (contact pressure roll) 1 according to the present invention has a small coefficient of friction with the sheet 25, wrinkles can be prevented and triboelectric charging can be reduced, so that a high-quality sheet roll body 21 can be wound up. .
[0040]
The reason why a roll body 21 free of wrinkles and charging defects can be obtained by using a low-friction rubber roll for the contact pressure roll 1 will be described below.
[0041]
Generally, in order to wind up the sheet 25 without wrinkles, it is necessary that there is no wrinkle when the sheet 25 enters the contact pressure point with the contact pressure roll 1. At this time, if the rubber roll 1 holding the sheet 25 and the sheet 25 are slippery, wrinkles are hardly formed due to the inherent rigidity of the sheet, and the wrinkles can be extended. In general, when the sheet roll body 21 is pressed by the contact pressure roll 1, the rubber is deformed, so that the surface speed of the rubber does not coincide with the surface speed of the sheet roll body 21, and friction always occurs due to the speed difference. Since the frictional charging is a cause of the charging defect that degrades the quality of the sheet roll body 21, the friction can be reduced by lowering the friction coefficient of the rubber surface, and as a result, the frictional charging can be reduced. It is.
[0042]
Further, as the rubber roll 1 for contact pressure, in order to remove air by following minute irregularities of the roll body 21 due to uneven thickness of the sheet 25 or the like, a rubber having a surface hardness softer than the winding hardness of the roll body 21 is used. Preferably it is. The winding hardness is measured by the same method as the rubber hardness. Further, if the hardness of the rubber roll 1 is too low, the amount of deformation at the time of contact pressure becomes large and the fatigue of the rubber is accelerated, and the layer composed of a large number of small regions may not be able to follow the amount of deformation of the rubber. Therefore, the rubber hardness is desirably 30 to 70 degrees.
[0043]
【Example】
Next, embodiments of the present invention will be described in detail with reference to the drawings. An iron core was used for the core 2 of the rubber roll 1 shown in FIG. 1, and chloroprene rubber having a hardness of 40 degrees was used for the rubber layer 3. The carbon film 4 was formed to a thickness of 1.0 μm by a plasma CVD method shown in FIG. 2 using a molecular gas containing carbon, oxygen, and hydrogen as shown in Patent Document 7.
(Example 1)
The dynamic and static friction coefficient of the rubber roll having the DLC film 4 formed as shown in FIG. 1 was 0.28.
[0044]
Further, using a polyethylene terephthalate film “Lumirror” manufactured by Toray Co., Ltd., having a thickness of 6 μm and a center line average surface roughness SRa = 20 nm cut out into a 200 mm × 300 mm sheet as a sheet, using a rubber roll having a surface length of 200 mm and a diameter of 100 mm. When the triboelectric charge was determined, the potential of the film was -0.5 kV. As shown in FIG. 4, the triboelectric charge amount was determined by rolling the rubber roll 1 on the sheet 33 by hand at a speed of 50 mm / sec by hand so as not to slide the rubber roll 1, then gripping the sheet 33 in the air, and setting the potential of the sheet 33 with respect to the ground. Was measured at a distance of 40 mm at 5 points using an electrometer (Model-523, manufactured by Trek) and expressed as an average value. At this time, in order to suppress the influence of the triboelectric charging on the back surface of the sheet 33 to be measured, a sheet 32 of the same kind and the same size is used as an underlay, and further below it, a 500 mm square metal plate connected to a smooth ground on the surface is provided. 31 is used. In addition, this measurement was implemented in the room of the environment of temperature 25 degreeC and humidity 60% RH.
(Example 2)
As shown in FIG. 3, a chloroprene rubber roll having a DLC film formed thereon was used as a contact pressure roll, and the polyethylene terephthalate film of Example 1 was wound. When a polyethylene terephthalate film having a thickness of 6 μm, a width of 200 mm and a length of 2000 m was wound up at a speed of 300 m / min, a sheet roll 21 of good quality was obtained.
(Comparative Example 1)
The same evaluation as in Example 1 above was performed using a chloroprene rubber roll having a hardness of 40 degrees without forming a DLC film. As a result, the dynamic friction coefficient was 1.0, and the charge of the polyethylene terephthalate film was -1.5 kV.
(Comparative Example 2)
The same evaluation as in Example 2 above was performed using a chloroprene rubber roll having a hardness of 40 degrees without forming a DLC film. The conditions such as the type of the film, the winding speed, the winding tension, and the contact pressure are the same as those in the second embodiment. As a result, two to three wrinkles were generated in the circumferential direction, and the quality of the roll of the sheet roll body was not good.
[0045]
【The invention's effect】
As apparent from the above description, according to the present invention, it is possible to provide a roll having a small frictional resistance and being sufficiently flexible for practical use, and to improve the durability. In addition, by using this rubber roll, a sheet roll having good winding appearance quality can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a rubber roll according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of a DLC film forming apparatus according to an embodiment of the present invention.
FIG. 3 is a configuration diagram of a winding device using a contact pressure rubber roll according to an embodiment of the present invention.
FIG. 4 is a diagram showing a charging evaluation method used in Examples and Comparative Examples.
[Explanation of symbols]
1: Rubber roll 2: Core 3: Rubber layer 4: DLC film 10: Vacuum container 11: Exhaust device 12: Rubber roll 13 to be processed: Roll rotation driving device 14: Discharge electrode 15: Power supply 16: Gas introducing means 20: Winding Core 21: Sheet roll 22: Swing arm 23: Pivot shaft 24: Hydraulic cylinder 25: Sheet 31: Metal plate 32: Underlay sheet 33: Sheet to be charged

Claims (8)

A roll having a surface static friction coefficient of 0.3 or less and a hardness in the range of 30 to 70 degrees. A layer of a material softer than the material forming the core is formed on the side surface of the roughly cylindrical core, and a number of small regions are independently formed in the roll plane direction on the surface of the layer of the soft material. The roll according to claim 1, wherein a layer is formed. The roll according to claim 1, wherein the plurality of small areas include a carbon film. The roll according to any one of claims 2 to 3, wherein the soft material contains at least one of a chloroprene rubber, a urethane rubber, a chlorosulfonated polyethylene rubber, and a silicone rubber. The roll according to any one of claims 2 to 4, wherein the layer composed of the plurality of small regions has a thickness of 10 nm to 3 µm. The roll according to any one of claims 2 to 5, wherein the core is made of a material containing FRP using carbon fiber as a reinforcing material. A sheet winding device comprising the roll according to claim 1 as a contact pressure roll. A method for manufacturing a sheet roll, which winds a sheet using the winding device according to claim 7 to form a sheet roll.

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